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An extracellular hollow tubular archaeal cell projection, characterized in Pyrodictium species, that extends from the cell envelope as a proteinaceous filament and forms networks between cells.

A non-membrane-bounded motility organelle, also called the archaellum, characterized in Archaea and in the bacterium Litorilinea aerophila; a membrane-associated motor drives swimming through rotation of extracellular type-IV-pilin-like archaellin filaments.

An extracellular helical archaellum filament assembled from glycosylated type-IV-pilin-like archaellin subunits and rotated by the archaeal-type flagellum motor for swimming; characterized in Archaea and in the bacterium Litorilinea aerophila.

A membrane-associated ATP-powered motor complex of the archaeal-type flagellum that assembles and rotates the external archaellin filament.

A membrane-bounded polar cell extension in Mycoplasma species that concentrates cytadherence and cytoskeletal proteins for host-cell attachment, gliding motility, and organelle-linked cell division.

The membrane surrounding the attachment organelle.

The rotary motility organelle of bacteria: a long helical filament of flagellin joined by a flexible hook to a basal body that spans the cell envelope. The basal body houses a rotor (MS and C rings) driven by membrane-embedded stator units that convert ion flow (H+ or Na+) into torque; the flagellar type III export apparatus at its base secretes the axial subunits. Not homologous to the archaeal archaellum or the eukaryotic cilium.

The basal cell-envelope substructure of a bacterial flagellum, consisting of a rod, a series of rings, Mot stator proteins, the switch complex, and the proximal flagellum-specific type III export apparatus.

The cytoplasmic FliG/FliM/FliN switch ring of the bacterial flagellar basal body, assembled on the MS ring to form the rotor face that receives torque from Mot/Pom stator units and changes rotational bias in response to phosphorylated CheY.

The portion of the central rod of the bacterial-type flagellar basal body that is distal to the cell membrane; spans most of the distance between the inner and outer membranes.

One of the rings of the bacterial-type flagellar basal body; anchors the basal body to the outer membrane.

One of the rings of the bacterial-type flagellar basal body; anchors the basal body to the peptidoglycan layer.

One of the rings of the bacterial-type flagellar basal body; a double-flanged ring that anchors the basal body to the cytoplasmic membrane.

The portion of the central rod of the bacterial-type flagellar basal body that is proximal to the cell membrane; the proximal rod connects the distal rod to the flagellar motor.

The central portion of the bacterial-type flagellar basal body, which spans the periplasm and threads through the rings.

The long, thin external propeller of the bacterial-type flagellum, formed by polymerized flagellin.

The proteinaceous structure at the distal tip of the bacterial-type flagellar filament.

The portion of the bacterial-type flagellum that connects the filament to the basal body.

The FlgK/FlgL hook-associated protein junction at the distal end of the bacterial-type flagellar hook that couples the flexible hook to the flagellin filament and buffers mechanical stress while initiating filament assembly.

A bacterial flagellar basal-body motor composed of an MS-ring/C-ring rotor complex and one or more Mot/Pom-family stator complexes in the cytoplasmic membrane that convert ion flow into rotary torque and bias clockwise or counterclockwise output.

The bacterial flagellar basal-body rotor built from the membrane-anchored FliF MS ring and the cytoplasmic FliG/FliM/FliN C ring, which together receive torque from stator units, rotate the axial rod, and bias clockwise or counterclockwise motor output.

A flagellum-specific type III export apparatus at the bacterial basal body, comprising a membrane-associated FlhA/FlhB/FliP/FliQ/FliR export gate and a cytoplasmic FliH/FliI/FliJ ATPase complex that support export of rod, hook, and filament subunits through the growing flagellum.

An ion-driven membrane complex in the bacterial flagellar motor, typically with five A subunits surrounding two B subunits, that transduces proton or sodium flow into torque on the flagellar rotor and anchors to the cell wall through the B subunits.

The portion of the plasma membrane surrounding a cilium.

A nine-bladed, propeller-like protein complex that links the distal end of the basal body and the cilium to the plasma membrane. Functions in protein sorting and gating (i.e. active and passive transport of proteins in and out of the cilium).

A region of the cilium between the basal body and proximal segment that is characterized by Y-shaped assemblages that connect axonemal microtubules to the ciliary membrane. The ciliary transition zone appears to function as a gate that controls ciliary membrane composition and separates the cytosol from the ciliary plasm.

A specialized eukaryotic organelle that consists of a filiform extrusion of the cell surface and of some cytoplasmic parts; it is largely bounded by an extrusion of the plasma membrane, contains a longitudinal microtubule array, and is anchored to a basal body.

Extracellular amyloid fibers assembled from CsgA by the Csg secretion and nucleation machinery that form a pilus subtype in enteric biofilm matrices.

A small, flexible, finger-like projection of cytoplasm containing an array of microtubles and located near the flagellar pores in some photosynthetic as well as nonphotosynthetic dinoflagellate species. Its functions are not fully understood, but it has been associated with feeding behavior (phagotrophy).

A mobile transmembrane junction at the tip of the flagellum of some kinetoplastid species linking the tip of a new growing flagellum to an older flagellum.

An archaeal cell-surface appendage composed of proteinaceous helical filaments with periodic prickles and a terminal grappling hook, used by Candidatus Altarchaeum hamiconexum cells to attach to biotic and abiotic surfaces.

An elongated, plasma-membrane-bounded, microtubule-supported appendage of haptophyte algae that emerges from the flagellar pole and can coil rapidly during haptonemal motility or participate in particle capture.

Non-membrane-bounded protein particle complex that carries cargo along axonemal microtubules during intraflagellar transport in eukaryotic cilia and flagella.

A hair-like structure covering the flagella found in some algae (heterokonts and cryptophytes). It is approximately 15 nm in diameter, and usually consist of a tubular shaft that itself terminates in smaller hairs. It is composed of glycoproteins and, likely, carbohydrates. Mastigonemes may assist in locomotion by increasing the surface area of a flagellum.

The projection formed by unicellular fungi in response to mating pheromone.

The region where the mating projection meets the bulk of the cell, in unicellular fungi exposed to mating pheromone.

The portion of the plasma membrane surrounding the mating projection.

The portion of the plasma membrane surrounding the mating projection tip.

An extracellular Geobacter sulfurreducens cytochrome nanowire assembled from OmcE tetraheme c-type cytochrome subunits and resolved by cryo-EM as a helical filament whose hemes pack within the filament core.

An extracellular electrically conductive Geobacter sulfurreducens PCA filament assembled as a helical array of OmcS six-heme c-type cytochrome monomers whose stacked hemes provide a path for long-range electron transport.

An extracellular electrically conductive Geobacter sulfurreducens filament assembled from the octaheme c-type cytochrome OmcZ; each subunit contributes a branched heme arrangement with a surface-exposed heme site to the cytochrome polymer.

A chaperone-usher adhesive pilus of uropathogenic Escherichia coli built from a PapA helical rod, a PapG-PapF-PapE tip fibrillum, a PapK adaptor that bridges the fibrillum to the rod, and a basal PapH terminator. The PapD chaperone delivers subunits to the PapC usher, which assembles the pilus, and the distal PapG adhesin binds host glycolipid receptors.

A large lattice-like axial structure found in some flagellated protists which extends alongside the axoneme. Protein components of the paraflagellar rod are likely implicated, among other, in adenine nucleotide signaling and metabolism, and in calcium signaling.

A bacterial-type flagellar appendage of spirochetes whose filaments reside in the periplasmic space between the cytoplasmic and outer membranes, attach near the cell poles, and rotate to deform the cell cylinder for motility.

A proteinaceous hair-like appendage on the surface of bacteria ranging from 2-8 nm in diameter.

A tubular projection of the bacterial cell envelope and cytoplasm that extends away from the main cell body in prosthecate bacteria. In stalked Caulobacter cells, the prostheca contains the inner membrane, peptidoglycan and outer membrane layers of the Gram-negative envelope and supports stalk-specific protein localization.

A disk-like multiprotein diffusion barrier that spans the Caulobacter stalk cross-section. StpABCD-containing stalk crossbands partition the prostheca into compartments by limiting exchange of soluble and membrane proteins between the cell body and stalk segments.

A tubular cell projection of suctorian ciliates that captures prey at its tip and conveys prey cytoplasm into the cell body.

A tight-adherence (Tad/Flp) subtype of type IV pilus involved in bacterial adhesion and colonization. In the Caulobacter vibrioides model, polar PilA filaments extend and retract during surface exploration and promote holdfast-dependent permanent attachment; this dynamic behavior is not asserted for every Tad system.

A mannose-sensitive adhesive bacterial pilus assembled by the chaperone-usher pathway. In the Escherichia coli model, a helical FimA rod carries an ordered FimH-FimG-FimF tip, is polymerized through the FimD usher, and ends in a basal FimI terminator. Other type I systems, including Salmonella, have different subunit inventories.

A dynamic bacterial surface filament assembled from type IV pilins by an inner-membrane ATPase machinery. Reversible extension and retraction can generate force for twitching motility, adhesion, surface sensing, and DNA uptake.

A Y-shaped protein complex in the ciliary transition zone that connects the cilium axoneme to the ciliary necklace. Both protein sorting and protein gating occur at this point in the cilium allowing some, but not all proteins to enter the cilium.

The complete 13-protofilament A tubule of the axonemal doublet microtubule.

An amorphous cytoplasmic assembly of actin filaments and selected actin-binding proteins in growth-arrested yeast cells, distinct from cortical actin patches and actin cables.

An endocytic patch formed from branched actin filaments just beneath the plasma membrane that assembles, moves, and disassembles rapidly.

A cytokinetic cytoskeletal ring composed of actin filaments, myosin, and accessory proteins that assembles beneath the plasma membrane and constricts during cell division.

A plasmid-encoded bacterial actin-like cytoskeletal filament assembled from AlfA ATPases that supports segregation of pLS32-family plasmids in Bacillus subtilis.

The microtubule-inner-protein network inside the lumen of the A tubule of the axonemal doublet microtubule.

The microtubule-inner-protein network inside the lumen of the B tubule of the axonemal doublet microtubule.

A 9+2 axonemal subassembly of the central microtubule pair, its projections, its tubule-bridging structures, and caps on the microtubule plus ends.

A bridge network that connects the C1 and C2 singlet microtubules of the 9+2 axonemal central apparatus.

A pair of asymmetric C1 and C2 singlet microtubules at the center of the 9+2 axonemal central apparatus.

A projection structure that extends from the C1 or C2 singlet microtubule of the 9+2 axonemal central apparatus.

A cellular anatomical entity that is part of an axoneme consisting of a doublet microtubule.

A dynein complex found in eukaryotic cilia and flagella; the motor domain heads interact with adjacent microtubules to generate a sliding force which is converted to a bending motion.

A microtubule in the axoneme of a eukaryotic cilium or flagellum; an axoneme contains nine modified doublet microtubules, which may or may not surround a pair of single microtubules.

A structure that joins the B10 protofilament of the B tubule to the A1 protofilament of the A tubule within an axonemal microtubule doublet.

A structural network of microtubule inner proteins located inside the lumens of the A and B tubules of the axonemal microtubule doublet that helps stabilize the doublet microtubule.

A junctional axonemal doublet substructure that links the B-tubule B1 protofilament to A-tubule protofilaments A10 and A11.

A three-protofilament ribbon formed by A-tubule protofilaments A11, A12 and A13 plus associated microtubule inner proteins that separates the A- and B-tubule lumens within an axonemal doublet microtubule.

A protein complex in ciliary and flagellar axonemes that interconnects neighboring outer doublet microtubules.

A microtubule-based bundle with associated proteins that forms the core of a eukaryotic cilium or flagellum.

The incomplete 10-protofilament B tubule of the axonemal doublet microtubule.

A cytoskeletal filament assembled from beta-helical bactofilin proteins. In bacteria, these filaments provide scaffolds for species-specific cellular organization, including polar stalk biogenesis in Caulobacter vibrioides.

A protein network at the lumen-facing interface between the A- and B-tubules of a basal-body triplet microtubule, forming connections between the two tubules with region-specific composition.

A proteinaceous intertriplet linkage connecting the A-microtubule of one triplet to the C-microtubule of the neighboring triplet in the wall of a ciliary basal body.

A microtubule-associated subassembly in the proximal region of a ciliary basal body, identified in Paramecium tetraurelia as a protruding density between A-microtubule protofilaments A8 and A9, adjacent to but distinguishable from the A-C linker.

A proteinaceous junction network at the lumen-facing interface between the B- and C-tubules of a basal-body triplet microtubule, connecting the two tubules with region-dependent composition.

A hook-shaped proteinaceous linker at the external B-C interface of a basal-body microtubule triplet. In the distal half of isolated Chlamydomonas reinhardtii basal bodies, hook densities occupy the C1 position, extend across the outer surfaces of C2-C4, and recur along the triplet axis.

A crescent-shaped proteinaceous filament inside the lumen of a basal-body C-tubule, spanning from protofilament C3 to the C6-C7 junction and occurring in a longitudinally repeated array in the distal half of isolated Chlamydomonas reinhardtii basal bodies.

A proteinaceous hub-and-spoke assembly at the proximal region of a microbial ciliary basal body or pro-basal body. Its central hub bears nine radially arranged spokes that connect toward the surrounding microtubules; the hub and spokes extend longitudinally as a stacked scaffold.

A morphologically distinct subassembly within the lumen of a microbial basal-body cartwheel hub, observed as a central electron-dense unit separate from the surrounding hub rings and radial spokes. Such units can repeat along the cartwheel axis, with nonuniform occupancy.

A longitudinal subassembly at the periphery of a microbial ciliary basal-body or pro-basal-body cartwheel, linking the outer radial-spoke ends along the cartwheel axis. In characterized Chlamydomonas and Paramecium regions it is distinguishable from the pinhead and extends into the proximal cartwheel segment beyond the microtubule wall.

An apparently continuous filamentous subassembly extending longitudinally within the lumen of a microbial basal-body cartwheel hub. It is morphologically distinguishable from the surrounding hub rings and spokes and from discontinuous cartwheel inner-density units.

A proteinaceous meshwork lining the lumen-facing surface of the central basal-body wall and interconnecting neighboring triplet microtubules through multiple attachment sites.

A proteinaceous subassembly on the luminal face of the A-tubule in the proximal region of a microbial ciliary basal body or pro-basal body, forming the peripheral connection toward the cartwheel spokes. In Chlamydomonas reinhardtii it has a bent pinbody and two pinfeet attached to protofilament A3.

A linker in the proximal region of a microbial ciliary basal body that connects the pinhead to the A-C linker. In Paramecium tetraurelia reconstructions it extends to the ArmB region of the A-C linker.

An electron dense ring at the most posterior position of the apical complex, from which the subpellicular microtubules originate; formed during an invasive life cycle stage of an apicomplexan parasite.

A cytoskeletal structure in some kinetoplastid species linking the structures of the ciliary pocket collar and the flagellum attachment zone.

A bacterial cytoskeletal microtubule assembled from BtubA and BtubB tubulin homologs that form tube-like filaments in Prosthecobacter cells and in purified BtubA/B reactions.

The asymmetric C1 singlet microtubule of the axonemal central pair.

The asymmetric C2 singlet microtubule of the axonemal central pair.

A contractile ring, i.e. a cytoskeletal structure composed of actin filaments and myosin, that forms beneath the plasma membrane at the mother-bud neck in mitotic cells that divide by budding in preparation for completing cytokinesis. An example of this structure is found in Saccharomyces cerevisiae.

A tubular structure with flared ends, shaped like an hourglass and composed of highly ordered arrays of septin filaments, that forms at the bud neck of a dividing cell. In S. cerevisiae, this structure is located at the bud neck throughout most of the cell cycle and the septins are fixed within the structure, not exchanging with soluble septins. This septin structure acts as a scaffold for other proteins that function at the bud neck.

A ring-shaped structure that forms at the site of cytokinesis in the bud neck of a budding cell; composed of members of the conserved family of filament forming proteins called septins as well as septin-associated proteins. In S. cerevisiae, this structure forms at the time of bud emergence and the septins show a high rate of exchange.

Two separate septin rings that are formed from the septin collar at the time of cytokinesis in cells that divide by budding. These two rings are thought to delineate a special compartment in which factors involved in cytokinesis are concentrated.

One of three laminate structures that form the mitotic spindle pole body; the central plaque is embedded in the nuclear envelope.

One of three laminate structures that form the spindle pole body; the central plaque is embedded in the nuclear envelope.

An archaeal tubulin-like cytoskeletal filament assembled from CetZ proteins that forms dynamic envelope-associated structures and supports cell-shape remodeling such as rod development in Haloferax volcanii.

Arrays of septin filaments, or bars, found in a series of filamentous structures. Observed in the chlamydospore membrane during chlamydospore formation.

A membrane-tethered, short cylindrical array of microtubules and associated proteins found at the base of a eukaryotic cilium or flagellum that derives from a centriole, anchors the cilium and nucleates axonemal microtubule growth.

A rod-shaped protein complex containing Centrin4 protein that flanks the flagellum attachment zone (FAZ) filament and the quartet microtubules.

A constriction site at the junction of the plasma, flagellar and flagellar pocket membranes where the flagellum emerges from the cell body. Observed in some unicellular eukaryotic species such as Chlamydomonas, Giardia and Trypanosoma.

A cytoskeleton-like structure, originating from the basal body at the proximal end of a cilium, and extending proximally toward the cell nucleus. Rootlets are typically 80-100 nm in diameter and contain cross striae distributed at regular intervals of approximately 55-70 nm.

Any of a series of structures composed of septins and septin-associated proteins localized to the cleavage plane which are involved in cytokinesis.

A spiral cytoskeletal structure located at the apical end of the apical complex in some apicomplexan parasites. Fibers form a left-handed spiral, and are comprised of tubulin protofilaments organized in a ribbon-like structure that differs from the conventional tubular structure characteristic of microtubules.

A bacterial intermediate filament-like cytoskeletal filament assembled from crescentin that localizes along the inner curvature of Caulobacter vibrioides cells and helps maintain their curved cell shape.

A peripheral centrin-positive cytoskeletal network observed in cryptophyte cells by ultrastructure expansion microscopy. It forms a regular hexagonal mesh in Rhinomonas nottbeckii and shows variable network patterns among Rhodomonas isolates. The assembly is distinct from basal-body-associated centrin structures and from the periplast itself.

A filamentous, membrane-less subcellular structure composed primarily of polymerized metabolic enzymes, most notably cytidine triphosphate synthase (CTPS). Cytoophidia are evolutionarily conserved structures found across archaea, bacteria, and eukaryotes.

Any microtubule in the cytoplasm of a cell.

A largely unbranched, centrin-containing extension of the infraciliary lattice associated with the cytostome-cytopharynx region, characterized in Paramecium. It is a named fibrillar substructure, not the entire lattice or the adjacent cytopharyngeal microtubular ribbons.

Inward projections of the cytoskeletal structures of the oral apparatus, which form a fiber that extends past the cytostome into the cytoplasm.

A centrin-containing fibrous bridge connecting the distal regions of paired flagellar basal bodies in green algae. It is distinct from proximal connecting fibers and nucleus-directed rootlets; cross-striation differs between the documented examples.

A filamentous cortical structure formed, in S. pombe, by the eisosome component Pil1.

A system of calmyonemin-containing contractile filament bundles associated with the bases of retractile apical ciliature in entodiniomorphid ciliates, characterized in Eudiplodinium maggii and Entodinium bursa. This record denotes the subkinetal bundles, not all other calmyonemin-positive arrays or the cilia themselves.

A microtubule organizing center formed by a band of gamma-tubulin that is recruited to a circumferential band of F-actin at the midpoint of a cell and which nucleates microtubules from the cell division site at the end of mitosis.

A network of cytoskeletal and membranous connections responsible for the lateral attachment of the cilium to the cell body in some trypanosomatid species.

A Giardia trophozoite cytoskeletal structure composed of short microtubule arrays that emanate from the caudal flagellar axonemes, anchor to dense rods running parallel to the posterior-lateral flagella, and after posterior-lateral flagellar emergence anchor to the epiplasm beneath the contractile tail membrane.

A faint structure formed of septins found at the leading edge of growth in germ tubes of fungal cells growing filamentously. This cap of septins colocalizes with a region of the plasma membrane that is rich in ergosterol.

A tight ring-shaped structure that forms in the division plane within the germ tube of filamentous fungi at sites where a septum will form; composed of septins as well as septin-associated proteins.

A protein complex involved in septin ring formation during mitosis. In Saccharomyces cerevisiae it consists of BNI5, CDC3, CDC10, CDC11, CDC12, GIN4, NAP1 and SHS1. At least 2 GIN4 molecules are involved.

Structure adjacent to the plaques of the mitotic spindle pole body.

Structure adjacent to the plaques of the spindle pole body.

An array of astral microtubules that emanates from the spindle pole body during meiosis and facilitates horsetail nuclear movement.

A septin collar in pathogenic fungi involved in the constriction of hyphae at the plant plasmodesma enabling penetration of an adjacent cell.

A septin band, i.e. a diffuse ring composed of a series of septin bars running parallel to the long axis of the cell, located at the junction between the mother cell and the germ tube (hypha) of a fungal cell growing filamentously.

A faint structure formed of septins found at the leading edge of growth in hyphae of fungal cells growing filamentously. This cap of septins colocalizes with a region of the plasma membrane that is rich in ergosterol.

A tight ring-shaped structure that forms in the division plane within hyphae of filamentous fungi at sites where a septum will form; composed of septins as well as septin-associated proteins.

A basal-body-associated centrin assembly described in Paramecium tetraurelia as a functional complex of ICL1e-subfamily proteins. It appears as a discrete ICL1e-positive dot and persists in cells lacking the extended infraciliary lattice; it is distinct from the whole lattice and from the complete infraciliary-lattice organizing-centre remnant.

A subcortical, calcium-responsive contractile network of centrin-containing filaments in Paramecium, assembled with Sfi1-like centrin-binding proteins. The mesh extends beneath the cell surface and is distinct from the basal-body-associated organizing centres and ICL1e complex that can persist when the extended lattice is lost.

An axonemal dynein complex that forms an inner dynein arm on ciliary and flagellar outer doublet microtubules.

One of three laminate structures that form the mitotic spindle pole body; the inner plaque is in the nucleus.

One of three laminate structures that form the spindle pole body; the inner plaque is in the nucleus.

The layer of the mitotic spindle pole body between the central plaque and the outer plaque.

The layer of the spindle pole body between the central plaque and the outer plaque.

A microtubule organizing center found in interphase cells, which organize a longitudinal array of three to five MT bundles from the nuclear envelope during interphase. Each MT bundle is composed of two to seven MTs arranged in an antiparallel configuration, with the dynamic MT plus ends extending toward the cell tips and stable minus ends near the nucleus.

A SIN signaling complex associated with the old spindle pole body during interphase in an inhibitory configuration. In Schizosaccharomyces pombe, the Byr4-Cdc16 GAP inhibits the Spg1 GTPase. Dma1-dependent ubiquitination of the Sid4 scaffold antagonizes Plo1 recruitment in G2 and during a mitotic checkpoint arrest.

A microtubule located such that it threads through the conoid and projects through the polar ring.

An actin-like bacterial cytoskeletal filament assembled from MamK proteins that runs alongside magnetosomes in magnetotactic bacteria and helps organize the organelles into chains.

A focus at the mating projection tip where the cell wall is degraded during cytogamy. Actin filaments form an aster-like structure from this location.

A septin band, i.e. a diffuse ring composed of a series of septin bars running parallel to the long axis of the cell, located at the neck of a shmoo (mating projection).

A septin ring, i.e. a ring-shaped structure composed of septins and septin-associated proteins, located at the neck of a shmoo (mating projection). The septin ring in the neck of a shmoo may act as a barrier to localize mating factors in the shmoo tip.

A ring-shaped structure that forms at the medial cortex of a symmetrically dividing cell at the onset of cytokinesis; composed of members of the conserved family of filament forming proteins called septins as well as septin-associated proteins.

A non-membrane bound, semi-organized microtubule array of unknown function found in Giardia species (trophozoite stage). It is located on the dorsal side of the trophozoite, slightly posterior to the ventral disc.

A cytoskeletal structure composed of actin filaments, myosin, and myosin-associated proteins that forms beneath the plasma membrane of many cells, including animal cells and yeast cells, in a plane perpendicular to the axis of the meiotic spindle, i.e. the cell division plane. Ring contraction is associated with centripetal growth of the membrane that divides the cytoplasm of the two future daughter cells. In animal cells, the meiotic contractile ring is located inside the plasma membrane at the location of the cleavage furrow. In fungal cells, the meiotic contractile ring forms beneath the plasma membrane of the prospore envelope in preparation for completing cytokinesis.

A sporulation-specific cytoplasmic plaque that forms on meiosis II spindle pole bodies in budding yeast after outer-plaque remodeling and nucleates prospore membrane assembly.

A heterooligomeric septin complex that acts during meiotic cell division.

The microtubule organizing center that forms as part of the meiotic cell cycle; functionally homologous to the animal cell centrosome.

Any of the long, generally straight, hollow tubes of internal diameter 12-15 nm and external diameter 24 nm found in a wide variety of eukaryotic cells; each consists (usually) of 13 protofilaments of polymeric tubulin, staggered in such a manner that the tubulin monomers are arranged in a helical pattern on the microtubular surface, and with the alpha/beta axes of the tubulin subunits parallel to the long axis of the tubule; exist in equilibrium with pool of tubulin monomers and can be rapidly assembled or disassembled in response to physiological stimuli; concerned with force generation, e.g. in the spindle.

A cytoskeletal structure composed of actin filaments, myosin, and myosin-associated proteins that forms beneath the plasma membrane of many cells, including animal cells and yeast cells, in a plane perpendicular to the axis of the mitotic spindle, i.e. the cell division plane. Ring contraction is associated with centripetal growth of the membrane that divides the cytoplasm of the two future daughter cells. In animal cells, the mitotic contractile ring is located inside the plasma membrane at the location of the cleavage furrow. In Saccharomyces cerevisiae, Myo1 localizes to a ring at the future bud site before bud emergence; actin joins this ring at the mother-bud neck near the end of anaphase to form the cytokinetic actomyosin ring.

A heterooligomeric septin complex that acts during mitotic cell division.

A spindle that forms as part of mitosis. Mitotic and meiotic spindles contain distinctive complements of proteins associated with microtubules.

The microtubule organizing center that forms as part of the mitotic cell cycle; functionally homologous to the animal cell centrosome.

The actin-like cytoskeletal filament of rod-shaped bacteria. MreB polymerises into short membrane-associated filaments that circle the cell at an angle to its long axis and move processively around it, carrying the elongasome — the peptidoglycan synthases that widen the sidewall — so that new wall material is inserted where the filaments travel. It is a homologue of eukaryotic actin by fold, not by sequence identity.

The spindle pole body that is formed by spindle pole body duplication, and to which proteins involved in mitotic exit signaling (for example, the septation initiation network in fission yeast) localize.

A SIN signaling complex associated with the new mitotic spindle pole body during anaphase and characterized by the presence activated (GTP bound) GTPase (Spg1 in fission yeast) to activate SIN signaling.

Any microtubule in the nucleus of a cell.

A centrin-containing fibrous root system that links flagellar basal bodies to the nuclear surface. It is a specialized nucleus-associated rootlet system, not the entire basal apparatus or the fibers connecting basal bodies to one another.

The spindle pole body that existed before the most recent spindle pole body duplication. In unperturbed Schizosaccharomyces pombe mitosis, septation initiation network activity becomes restricted to the new pole in late anaphase B, after activity at both poles earlier in mitosis.

An axonemal dynein complex that forms the outer dynein arm on ciliary and flagellar outer doublet microtubules and contains dynein heavy, intermediate and light chains.

One of three laminate structures that form the mitotic spindle pole body; the outer plaque is in the cytoplasm.

One of three laminate structures that form the spindle pole body; the outer plaque is in the cytoplasm.

A plasmid-encoded bacterial actin-like cytoskeletal filament assembled from ParM that is captured and stabilized by ParR-parC plasmid-centromere complexes to support active segregation of low-copy-number plasmids such as Escherichia coli R1.

An interconnected contractile fiber system in the cell body of peritrich ciliates, comprising longitudinal and peristomial fibers. In Vorticella, body myonemes converge aborally into the distinct stalk spasmoneme. This record denotes the body network, not the stalk organelle, ciliary apparatus or an individual protein.

A phage-encoded tubulin-like cytoskeletal spindle assembled from PhuZ polymers that positions the jumbo-phage nucleus in infected bacterial cells.

An electron dense ring at the most anterior position of the apical complex, from which the conoid fibers originate; formed during an invasive life cycle stage of an apicomplexan parasite.

A cytoskeletal part that consists of an array of microtubules and associated molecules that forms at the end of anaphase, and in which microtubules are nucleated from an equatorial microtubule organizing center.

A contractile ring composed of actin filaments and myosin that forms beneath the plasma membrane of the prospore envelope in meiotic cells in preparation for completing cytokinesis.

Arrays of septin filaments, or bars, found in a series of filamentous structures; observed in the prospore membrane during spore formation.

A tight ring-shaped structure that forms in the division plane at the site of cytokinesis in a prospore; composed of septins as well as septin-associated proteins.

A tight ring-shaped structure that forms in the division plane at the junction between the mother cell and a pseudohyphal projection; composed of septins as well as septin-associated proteins.

A stable antiparallel cytoplasmic microtubule bundle assembled during nutrient-exhaustion-induced quiescence in fission yeast, characterized in Schizosaccharomyces pombe. It contains closely packed microtubules, is usually associated with the spindle pole body, and is distinct from the nuclear microtubule array of quiescent budding yeast.

A stable monopolar bundle of parallel nuclear microtubules formed during glucose-exhaustion-induced quiescence, characterized in Saccharomyces cerevisiae. The bundle extends from the nuclear face of the spindle pole body and reorganizes kinetochore and centromere distribution; it is distinct from the antiparallel cytoplasmic quiescent-cell bundle of fission yeast.

A transient, Hrs1/Mcp6-dependent, gamma-tubulin-enriched amorphous microtubule-organizing assembly at the cytoplasmic side of the spindle pole body during Schizosaccharomyces pombe meiotic prophase, distinct from the spindle pole body core, that organizes the radial microtubule array used in horsetail nuclear movement.

A ciliary and flagellar axonemal protein complex with a stalk attached to each outer-doublet A-tubule and a head that projects toward the central-pair microtubule sheath.

Protein complex forming portion of the radial spoke that is orthogonal to the elongated stalk and which projects towards the central pair of microtubules within the ciliary or flagellum axoneme.

The radial spoke neck is a complex that connects the spoke stalk to the head.

Protein complex forming the elongated portion of the radial spoke between the base which binds to the A-tubule of each microtubule outer doublet and the neck which connects to the spoke head within the ciliary or flagellum axoneme.

A diffuse ring composed of a series of septin bars that run parallel to the long axis of the cell. This type of septin structure has been observed in a number of locations associated with polarized growth and/or deposition of new membrane, but not with cytokinesis, such as at the shmoo (mating projection) neck, at the junction between the mother cell and the germ tube (hypha) of a fungal cell growing filamentously.

A faint structure formed of septins found at the leading edge of growth in germ tubes and hyphae in fungal cells growing filamentously. This cap of septins colocalizes with a region of the plasma membrane that is rich in ergosterol.

A tubular, hourglass-shaped structure composed of highly ordered arrays of septin filaments; in budding yeast cells, the septin collar forms from the initial septin ring by expanding into the daughter cell.

A protein complex containing septins. Typically, these complexes contain multiple septins and are oligomeric.

Arrays of septin filaments, or bars, found in a series of filamentous structures. Such structures have been observed in the prospore membrane during spore formation in S. cerevisiae and in the chlamydospore membrane during chlamydospore formation in C. albicans.

A tight ring-shaped septin-based cytoskeletal structure that forms at the cell cortex in the division plane, including the bud-neck septin ring of budding yeast and related fungal septin rings at septation sites.

A protein complex associated with the mitotic spindle pole body during interphase and mitosis and comprises of the proteins of the septation initiation signaling network (SIN) of fission yeast or mitotic exit network (MEN) of budding yeast, organized by two scaffold/adaptor proteins.

A protein complex that acts as a two-component GTPase-activating protein for the Tem1/Spg1 GTPase, thus regulating a signal transduction cascade (the mitotic exit network, MEN, in budding yeast; the septation initiation network, SIN, in fission yeast), which is required for mitotic exit and cytokinesis. The complex keeps the GTPase inactive until the spindle is properly oriented, thus inhibiting MEN/SIN activation.

A striated, wedge-shaped fibrous linker connecting a flagellar basal body to a five-microtubule s-type root in Spermatozopsis similis. Its BAp95-containing assembly is distinct from the root microtubules, SF-assemblin fibers, centrin fibers and proximal interbasal plates.

Any microtubule that is part of a mitotic or meiotic spindle; anchored at one spindle pole.

The microtubule-organizing center in fungi, functionally homologous to the animal centrosome.

A transient cytoplasmic plaque intermediate formed after spindle pole body satellite expansion during daughter spindle pole body assembly in budding yeast.

A transient cytoplasmic precursor of the daughter spindle pole body that forms at the distal tip of the half bridge during spindle pole body duplication in budding yeast.

A mesh-like cortical myoneme characterized in Spirostomum, containing intersecting centrin/spasmin-rich fibrillar bundles and giant Sfi1-like scaffold proteins. The extended network shortens during calcium-triggered cell contraction and is distinct from adjacent microtubule bundles and from an isolated scaffold-centrin protein complex.

A pair of rings that flank the site of cell division, formed by splitting of the septin ring (or collar) prior to cytokinesis; this double ring structure is thought to trap proteins needed for cytokinesis or the formation of the new membrane or cell wall between the two septin rings. Split septin rings are known to occur in budding yeast cells and probably occur in other cell types as well.

An intracellular contractile fibrillar organelle within the stalk of contractile-stalk peritrich ciliates. A spasmin-rich fibrillar mass is interspersed with membrane-bounded tubules. Shortening deforms the surrounding stalk; the organelle is distinct from the extracellular sheath and from the continuous body myoneme network.

A longitudinal cortical bundle of overlapping microtubule ribbons in Stentor, characterized ultrastructurally in S. coeruleus. Ribbons originate beside successive basal-body pairs and overlap alongside a ciliary row; the bundle is distinct from the deeper contractile myonemes.

The cortical system of longitudinal contractile filament bundles, historically termed M bands, characterized in Stentor coeruleus. Its prominent posterior myonemes are distinct from the adjacent microtubular Km fibers; this record does not denote every centrin-containing cortical assembly.

An irregular cortical microtubule meshwork characterized in Stentor pyriformis, with gaps occupied by algal endosymbionts in perialgal vacuoles. The named basket system denotes host cytoskeletal architecture, not regular cages, the symbionts themselves, their vacuole membranes, or the longitudinal Km-fiber bundles.

A singlet microtubule that lies underneath the inner membrane pellicle complex and emanates from the basal ring of the conoid.

A protein complex that contains the transforming acidic coiled coil (TACC) protein and the TOG protein (Mia1p/Alp7p and Alp14, respectively, in fission yeast), and is involved in microtubule array remodeling as cells progress through the cell cycle. The TACC/TOG complex is conserved in eukaryotes, associates with microtubules, and shuttles between the nucleus and the cytoplasm during interphase.

A telomere-associated microtubule organizing assembly formed at the nuclear envelope during meiotic entry in Schizosaccharomyces pombe. It recruits a gamma-tubulin nucleation complex to SUN/KASH-linked telomeres and generates cytoplasmic microtubules that support their clustering at the spindle pole body; it is distinct from the spindle pole body and the completed telomere bouquet.

A centrin-containing system of luminal fibers forming a nine-pointed stellate array attached to the outer microtubule doublets of the Chlamydomonas ciliary transition zone. It is distinct from the peripheral Y-links and from the central cylinder around which the fibers extend.

A three-part cytoskeletal structure in kinetoplastid species linking mitochondrial DNA organised in a kinetoplast through the mitochondrial membranes to the basal body.

A compact spool-like tubulin-positive cytoskeletal structure observed in kareniacean dinoflagellates. In Takayama helix, ultrastructure expansion microscopy resolves perinuclear and posterior spools that appear continuous with microtubules. The name denotes the assembled structure, not a tubulin protein or the entire cortical microtubule array.

A plasmid-encoded bacterial tubulin-like cytoskeletal filament assembled from TubZ GTPase subunits that supports pBtoxis plasmid partitioning in Bacillus thuringiensis.

A specialized organelle in Giardia trophozoites that supports attachment to host intestinal epithelium. Its spiral microtubule array bears dorsal microribbons linked by crossbridges, and a lateral crest surrounds the disc edge.

A fibrous structure that horizontally links adjacent dorsal microribbons in the ventral disc of Giardia species trophozoites.

Trilaminar structure extending perpendicularly into the cytoplasm along the length of ventral disc microtubules in Giardia species (trophozoite stage). Constituents of dorsal microribbons (also called dorsal ribbons or microribbons) include alpha-coiled-helix proteins approximately 29 to 38 kDa in size. These proteins line the edges of the microribbons but are not found in microtubules. Tubulins are not found in microribbons.

A fibrillar repetitive structure that surrounds the edge of the ventral disc in Giardia species trophozoites.

A part of the ventral disc of Giardia species (trophozoite stage) consisting of a spiral array of microtubules linked to the ventral membrane. These microtubules form the base of the ventral disc dorsal microribbons that extend nearly perpendicular from the membrane.

A region of the ventral disc of Giardia species (trophozoite stage) where two portions of the same array of microtubules overlap (the microtubule array makes a complete circle and overlaps on itself).

A partial spiral microtubule array associated with the Giardia trophozoite ventral disc and distinct from its main microtubule array. Schwartz et al. 2012 reconstructed a short right-handed fragment lying ventral to the main array.

The membrane-associated protein machine that builds the peptidoglycan division septum in FtsZ-dependent bacterial cytokinesis. Membrane-tethered FtsZ filaments organize the division site and help distribute septal synthases; movement during active synthesis is not universally driven by FtsZ treadmilling.

The membrane-associated Rod complex that synthesizes lateral peptidoglycan during rod-shaped growth in model bacteria such as Escherichia coli and Bacillus subtilis. Its SEDS-family RodA polymerase works with an elongation-specific class B penicillin-binding transpeptidase, PBP2 in E. coli. Associated MreB filaments orient synthesis, while wall synthesis and filament motion are coupled; this is not a universal mechanism of rod shape in all bacteria.

A bacteriochlorophyll a-CsmA light-harvesting protein-pigment array on one face of green bacterial chlorosomes that accepts excitation energy from chlorosome bacteriochlorophyll aggregates and couples it toward membrane reaction-center complexes.

A purple-bacterial chromatophore membrane cytochrome bc1 protein complex that oxidizes quinol from the chromatophore quinone pool and returns electrons toward reaction-center antenna cores through soluble cytochrome c2 during cyclic photosynthetic electron transport.

A thylakoid membrane protein complex that oxidizes plastoquinol, reduces a downstream soluble electron carrier for photosystem I, and contributes to proton translocation during oxygenic photosynthetic electron transport.

Cytochrome bd-I ubiquinol oxidase complex is a membrane-bound CydAB respiratory terminal oxidase with small bd-I accessory subunits that oxidizes ubiquinol, reduces molecular oxygen to water, and contributes to the respiratory proton motive force.

A four-polypeptide respiratory-chain protein complex that possesses cytochrome o ubiquinol oxidase activity and contains associated prosthetic groups.

A membrane-bound anaerobic dimethyl sulfoxide reductase complex that catalyzes the reduction of dimethyl sulfoxide to dimethyl sulfide during respiratory electron transport.

A nitrate-inducible, membrane-bound formate:quinone oxidoreductase complex whose FdnG, FdnH, and FdnI subunits oxidize formate and pass electrons to a membrane quinone during anaerobic respiration.

A membrane-bound Escherichia coli formate hydrogenlyase complex in which FdhF and HycB-HycG subunits couple formate oxidation to proton reduction, yielding carbon dioxide and hydrogen gas.

A membrane-bound four-subunit respiratory quinol:fumarate reductase complex whose extrinsic catalytic module and membrane-anchor module couple fumarate reduction to quinol oxidation.

A peripheral bacteriochlorophyll-containing light-harvesting antenna protein complex of purple bacterial chromatophore membranes that broadens the photosynthetic absorption cross-section and transfers excitation energy toward RC-LH1 reaction-center core complexes.

A protein-pigment complex that may be closely or peripherally associated to photosynthetic reaction centers that participate in harvesting and transferring radiant energy to the reaction center.

Methyl coenzyme M reductase complex is a hexameric alpha2 beta2 gamma2 enzyme complex that catalyzes coenzyme B-dependent reduction of methyl-coenzyme M to methane during the terminal step of methanogenesis.

A cytoplasmic membrane-bound NarGHI nitrate reductase complex with iron-sulfur, heme, and molybdenum-bis(molybdopterin guanine dinucleotide) cofactors that serves as a terminal reductase during anaerobic nitrate respiration.

A nitrogenase enzyme complex composed of tetrameric dinitrogenase and homodimeric nitrogenase reductase subcomplexes that together catalyze ATP-dependent reduction of dinitrogen to ammonia.

A photosystem that contains an iron-sulfur reaction center associated with accessory pigments and electron carriers. In cyanobacteria and chloroplasts, photosystem I functions as a light-dependent plastocyanin-ferredoxin oxidoreductase, transferring electrons from plastocyanin to ferredoxin; in photosynthetic bacteria that have only a single type I photosystem, such as the green sulfur bacteria, electrons can go either to ferredoxin (Fd) -> NAD+ or to menaquinone (MK) -> Cytb/FeS -> Cytc555 -> photosystem I (cyclic photophosphorylation).

A photosystem that contains a pheophytin-quinone reaction center with associated accessory pigments and electron carriers. In cyanobacteria and chloroplasts, in the presence of light, PSII functions as a water-plastoquinone oxidoreductase, transferring electrons from water to plastoquinone, whereas other photosynthetic bacteria carry out anoxygenic photosynthesis and oxidize other compounds to re-reduce the photoreaction center.

A membrane-associated light-harvesting pigment-protein complex of cyanobacteria and red algae, built from phycobiliprotein core and rod cylinders plus linker polypeptides, that funnels phycobilin excitation energy to photosynthetic reaction centers.

Allophycocyanin-containing central cylinder assembly of a phycobilisome that receives excitation energy from peripheral rods and routes it toward chlorophyll photosystems.

Peripheral phycobiliprotein cylinder subassembly of a phycobilisome that binds phycobilin chromophores, absorbs excitation energy, and transfers it inward to the allophycocyanin core.

A photosystem I protein complex located in the plasma membrane-derived bacterial thylakoid membrane.

A photosystem II protein complex located in the plasma membrane-derived bacterial thylakoid that contains a P680 reaction center and catalyzes the water-oxidizing, plastoquinone-reducing step of oxygenic photosynthesis.

The rotary motor enzyme that makes ATP from ADP and phosphate using the ion motive force across the membrane. It has two coupled sectors: a membrane-embedded Fo, whose c-ring turns as protons cross it, and a soluble F1 (alpha3beta3gammadeltaepsilon), whose catalytic beta subunits are driven through their conformational cycle by the rotating gamma subunit.

A purple-bacterial chromatophore membrane protein complex that contains a photochemical reaction center, LH1 antenna proteins and PufX, receives excitation from surrounding LH2 antennae, and reduces quinone during cyclic photosynthetic electron transport.

Respiratory chain complex I is an L-shaped enzyme of the respiratory chain that oxidizes NADH, routes electrons through a hydrophilic peripheral arm to quinone, and couples quinone reduction to proton translocation through a membrane arm.

Respiratory chain complex II (succinate dehydrogenase) is a respiratory-chain enzyme complex that oxidizes succinate, passes electrons through flavin and iron-sulfur centers to membrane quinone, and thereby connects tricarboxylic-acid-cycle electron flow with the respiratory quinone pool.

Respiratory chain complex III is a membrane-bound cytochrome bc1 oxidoreductase complex that uses a cytochrome b, Rieske iron-sulfur protein, and cytochrome c1 catalytic core to transfer electrons from quinol to cytochrome c while translocating protons.

Respiratory chain complex IV is a membrane-bound cytochrome c oxidase complex that transfers electrons from reduced cytochrome c to dioxygen and couples oxygen reduction to proton translocation across a respiratory membrane.

Sodium-translocating NADH:quinone reductase complex is a bacterial respiratory-chain protein complex composed of NqrA, NqrB, NqrC, NqrD, NqrE, and NqrF that transfers electrons from NADH to ubiquinone while exporting sodium ions across the cytoplasmic membrane.

A proton-transporting two-sector ATPase complex found in the vacuolar membrane, where it acts as a proton pump to mediate acidification of the vacuolar lumen.

The V0 domain of a proton-transporting V-type ATPase found in the vacuolar membrane.

The V1 domain of a proton-transporting V-type ATPase found in the vacuolar membrane.

A highly organized glycocalyx layer attached outside the cell wall of some bacteria and fungi, usually built from capsular polysaccharides and retained on the cell surface rather than released as a loose extracellular polymer.

The outermost lipid bilayer of a diderm cell envelope. In canonical Gram-negative bacteria it is asymmetric, with phospholipid enriched in the inner leaflet and lipopolysaccharide enriched in the outer leaflet, and contains beta-barrel proteins that mediate transport and assembly.

The specialized plasma-membrane region that surrounds a cellular bud.

An individual mineralized scale produced by a coccolithophore, with a characteristic arrangement of calcite crystals. Coccoliths form elements of the external cell covering, the coccosphere, and can be shed as free scales.

An external cell covering of a coccolithophore assembled from individual mineralized scales called coccoliths. Its organization varies among taxa and cell states; the covering is distinct from a single coccolith and from the intracellular vesicle in which a coccolith forms.

A cell septum which forms as part of the division site and functions in the compartmentalization of a cell into two daughter cells at division. A division septum spans a cell and does not allow exchange of organelles or cytoplasm between compartments.

A porous fungal cell septum in which the cross-wall swells around a central pore and the pore is capped on both sides by septal pore caps called parenthesomes.

A plasma membrane part that is composed of a furrow-like plasma membrane domain and associated integral transmembrane proteins.

A rigid but dynamic carbohydrate- and glycoprotein-rich wall surrounding the fungal plasma membrane, built from a variable cross-linked matrix of glucans, wall glycoproteins, and often chitin and kept distinct from fungal capsules outside the wall.

A carbohydrate rich layer at the outermost periphery of a cell.

The relatively thin peptidoglycan layer of a Gram-negative cell envelope, located in the periplasm between the cytoplasmic and outer membranes and physically connected to the outer membrane by lipoproteins.

A mycolic-acid-rich cell outer membrane in mycobacteria and related Corynebacteriales, containing a lipid bilayer and covalently linked long-chain mycolic acids attached to peptidoglycan through an arabinogalactan network.

The region between the inner (cytoplasmic or plasma) membrane and outer membrane of organisms with two membranes such as Gram negative bacteria. These periplasmic spaces are relatively thick and contain a thin peptidoglycan layer (PGL), also referred to as a thin cell wall.

A protective, load-bearing structure outside the cytoplasmic membrane, built from glycan strands of alternating N-acetylglucosamine and N-acetylmuramic acid cross-linked by short peptides. The resulting murein sacculus surrounds the cell and resists turgor pressure.

The region between the inner (cytoplasmic) and outer membrane (Gram-negative Bacteria) or cytoplasmic membrane and cell wall (Fungi and Gram-positive Bacteria).

The lipid membrane surrounding a cell that separates the cytoplasm from the external environment and houses proteins for selective transport, signaling, and envelope biogenesis.

A paracrystalline monomolecular array of one or more (glyco)protein species that self-assemble on the outermost surface of the cell envelope, with oblique, square or hexagonal lattice symmetry. S-layers are common in Archaea, where they are often the sole wall component, and widespread but patchily distributed in Bacteria.

A slime layer is an easily removed, diffuse, unorganized layer of extracellular material that surrounds a cell. Specifically this consists mostly of exopolysaccharides, glycoproteins, and glycolipids.

An aging-associated protein inclusion characterized in budding yeast that collects aggregation-prone proteins, usually persists as a single ER-associated deposit, and is preferentially retained in the mother-cell lineage.

A stress-associated, membraneless cytoplasmic inclusion in bacteria that concentrates endogenous proteins and can sequester mRNA; Escherichia coli aggresomes exhibit liquid-like dynamics and preserve selected transcripts during stress.

A bacterial storage inclusion in which insoluble cyanophycin polymer accumulates as cytoplasmic granules that store fixed nitrogen and carbon for later mobilization.

A gas-filled, non-membrane-bounded protein organelle, usually shaped as a cylindrical shell with conical end caps. Its gas-permeable, water-excluding wall lowers cell density and enables buoyancy regulation in aquatic microbes.

The proteinaceous structure surrounding a gas vesicle.

A microbial carbohydrate storage inclusion in which glycogen polymer accumulates as cytoplasmic granules that store glucose-derived carbon and energy for later mobilization.

A perivacuolar cytoplasmic protein inclusion characterized in budding yeast that accumulates poorly mobile, insoluble protein aggregates, including amyloid and prion cargo, at a site distinct from nuclear and juxtanuclear quality-control deposits.

A stress-induced membraneless nuclear inclusion characterized in budding yeast that concentrates misfolded and other conditionally recruited proteins near the nuclear envelope, distinct from the cytoplasmic juxtanuclear quality control compartment.

A cytoplasmic, perinuclear protein-quality-control inclusion characterized in budding yeast, formed by congregation of misfolded-protein deposits near the nuclear envelope and distinct from the intranuclear quality control compartment.

An intracellular non-membrane-bounded organelle comprising a matrix of coalesced lipids surrounded by a phospholipid monolayer. May include associated proteins.

A transient cytosolic protein granule characterized in budding yeast that sequesters non-imported mitochondrial precursor proteins, is enriched for presequence-containing cargo and associates with the mitochondrial surface.

The single layer of phospholipids surrounding a lipid storage body.

An intranuclear inclusion at the nucleolar periphery in which nuclear factors collect reversibly during acute heat stress or starvation.

A proteinaceous Bacillus thuringiensis inclusion body that accumulates Cry, Cyt, and related pesticidal crystal proteins as a parasporal crystalline deposit.

A lipoprotein particle present in chloroplasts.

A cytoplasmic prokaryotic inclusion body in which polyhydroxyalkanoate storage polymers condense with granule-associated proteins, including PHA synthases and phasins, to form hydrophobic carbon- and reducing-power storage granules.

A cytoplasmic, membrane-free accumulation of proteasome core and regulatory particles observed as discrete foci during cellular quiescence.

A reversible intracellular assembly of misfolded proteins and chaperones that temporarily protects heat-sensitive clients from degradation and can be disassembled when conditions permit recovery.

A bacterial proteinaceous inclusion body assembled from Reb proteins that forms a coiled ribbon and can extend into a hollow tube.

A bacterial sulfur storage inclusion that accumulates elemental sulfur from reduced sulfur compounds and packages it with sulfur-globule envelope proteins for temporary storage and later oxidation.

An acidic electron-dense membrane-bounded organelle found in diverse microbes that stores polyphosphate, pyrophosphate, calcium and other cations and uses proton pumps and cation transporters to maintain its ion-rich matrix.

The acidocalcisome compartment bounded by the acidocalcisomal membrane.

The lipid bilayer surrounding an acidocalcisome.

A secretory granule beneath the cell or axopodial surface of actinophryid protists, containing amorphous electron-dense material released during prey capture.

A ladderane-lipid-bounded intracytoplasmic organelle of anaerobic ammonium-oxidizing Planctomycetota that localizes the hydrazine-producing anammox catabolic pathway and its energy-conserving membrane reactions.

The single ladderane-lipid-containing bilayer membrane that surrounds the anammoxosome.

Electron-dense organelle with a granular internal matrix found in a apicomplexan parasite; contains proteins destined to be secreted into the parasitophorous vacuole following parasite invasion of a host cell.

The lipid bilayer surrounding a dense granule of the type found in apicomplexan parasites.

The plastid organelle found in apicomplexans.

Any of the lipid bilayers that surround an apicoplast and form the apicoplast envelope.

A double-membrane-bounded compartment that engulfs endogenous cellular material as well as invading microorganisms to target them to the lytic vacuole/lysosome for degradation as part of macroautophagy.

The volume enclosed within the autophagosome double-membrane.

The membrane surrounding the autophagosome.

A thylakoid that is derived from and attached to, but not necessarily continuous with, the plasma membrane, and is not enclosed in a plastid. It bears the photosynthetic pigments in photosynthetic cyanobacteria.

An intracellular membrane-bounded particle found in fungi and containing chitin synthase; it synthesizes chitin microfibrils. Chitin synthase activity exists in chitosomes and they are proposed to act as a reservoir for regulated transport of chitin synthase enzymes to the division septum.

A chlorophyll-containing plastid with thylakoids organized into grana and frets, or stroma thylakoids, and embedded in a stroma.

The double lipid bilayer enclosing the chloroplast and separating its contents from the rest of the cytoplasm; includes the intermembrane space.

The inner, i.e. lumen-facing, lipid bilayer of the chloroplast envelope; also faces the chloroplast stroma.

The region between the inner and outer lipid bilayers of a chloroplast envelope.

Either of the lipid bilayers that surround a chloroplast and form the chloroplast envelope.

The cytoplasm-facing lipid bilayer of the chloroplast envelope.

The internal space enclosed by the chloroplast double membrane but excluding the thylakoid space.

Sac-like membranous structures in a chloroplast combined into stacks, or grana, and present singly in the stroma as stroma thylakoids or frets that interconnect grana.

The volume enclosed by the membrane of a chloroplast thylakoid.

The pigmented membrane of a chloroplast thylakoid.

A large light-harvesting antenna organelle of green photosynthetic bacteria in which bacteriochlorophyll aggregates self-assemble inside a lipid envelope and attach to the cytoplasmic membrane through a bacteriochlorophyll a-containing CsmA baseplate.

The structure, composed of a monolayer of glycolipids with embedded proteins, that encloses the pigments and other contents of the chlorosome.

That part of the plasma membrane found in the ciliary pocket (also called flagellar pocket).

The network of interconnected tubular and cisternal structures located at the convex side of the Golgi apparatus, which abuts the endoplasmic reticulum.

The lipid bilayer surrounding any of the compartments that make up the cis-Golgi network.

A clathrin-coated, membrane-bounded intracellular vesicle formed by invagination of the plasma membrane around an extracellular substance.

The volume enclosed by the membrane of a clathrin-coated endocytic vesicle.

The lipid bilayer surrounding a clathrin-coated endocytic vesicle.

A vesicle with a coat formed of clathrin connected to the membrane via one of the clathrin adaptor complexes.

The clathrin-coated vesicle compartment bounded by the clathrin-coated vesicle membrane.

The lipid bilayer surrounding a clathrin-coated vesicle.

Small membrane-bounded organelle formed by pinching off of a coated region of membrane. Some coats are made of clathrin, whereas others are made from other proteins.

The lipid bilayer surrounding a coated vesicle.

A membrane-bounded intracellular compartment of coccolithophores that encloses a developing calcite coccolith. Its bounding membrane surrounds the site of coccolith mineralization and can change shape as the crystals grow.

The lipid bilayer surrounding the contractile vacuole.

A specialized vacuole of eukaryotic cells, especially Protozoa, that fills with water from the cytoplasm and then discharges this externally by the opening of contractile vacuole pores. One of its functions is osmoregulatory.

A non-membrane-bounded organelle of eukaryotic cells, especially Protozoa, that fills with water from the cytoplasm and then discharges this externally. One of its functions is osmoregulatory.

The contractile vacuole compartment bounded by the contractile vacuole membrane.

Stable structure that regulates the flow of liquid between the contractile vacuole and the surrounding medium.

A vesicle with a coat formed of the COPI coat complex proteins. COPI-coated vesicles are found associated with Golgi membranes at steady state, are involved in Golgi to endoplasmic reticulum (retrograde) vesicle transport, and possibly also in intra-Golgi transport.

The COPI-coated vesicle compartment bounded by the COPI-coated vesicle membrane.

The lipid bilayer surrounding a COPI-coated vesicle.

A vesicle with a coat formed of the COPII coat complex proteins. The COPII coat complex is formed by the Sec23p/Sec24p and the Sec13p/Sec31p heterodimers. COPII-associated vesicles transport proteins from the rough endoplasmic reticulum to the Golgi apparatus (anterograde transport).

The COPII-coated vesicle compartment bounded by the COPII-coated vesicle membrane.

A cytosolic vesicle that is enclosed by a double membrane and is implicated in the cytoplasm to vacuole targeting pathway. These vesicles are found in the yeast S. cerevisiae, and contain vacuolar hydrolases, aminopeptidase I (Ape1p) and alpha-mannosidase (Ams1p).

The Cvt vesicle compartment bounded by the Cvt vesicle membrane.

Either lipid bilayer membrane surrounding a Cvt vesicle, a double membrane-layered vesicle implicated in the cytoplasm to vacuole targeting pathway.

A plastid that contains unstacked, phycobilisome-bearing thylakoid membranes and is surrounded by a double membrane with a peptidoglycan layer in the intermembrane space between the two envelope membranes. Cyanelles are characteristic of algae in the class Glaucophyta, and may represent an ancestral form of plastid.

The double lipid bilayer enclosing the cyanelle and separating its contents from the rest of the cytoplasm; includes the intermembrane space.

The inner, i.e. lumen-facing, lipid bilayer of the cyanelle envelope; also faces the cyanelle stroma.

The region between the inner and outer lipid bilayers of the cyanelle envelope; includes the peptidoglycan layer.

Either of the lipid bilayers that surround a cyanelle and form the cyanelle envelope.

The outer, i.e. cytoplasm-facing, lipid bilayer of the cyanelle envelope.

The space enclosed by the double membrane of a cyanelle.

A thylakoid found in a cyanelle, which is a type of plastid found in certain algae. The cyanelle contains a photosynthetic membrane resembling that of cyanobacteria.

The cyanelle compartment bounded by the thylakoid membranes.

The lipid bilayer membrane of any thylakoid within a cyanelle, a photosynthetic organelle of glaucocystophyte algae.

A vesicle found in the cytoplasm of a cell.

The volume enclosed by a cytoplasmic vesicle.

The lipid bilayer surrounding a cytoplasmic vesicle.

An obligate, membrane-bounded nitrogen-fixing compartment of Epithemia diatoms containing a reduced, nonphotosynthetic cyanobacterial endosymbiont; a metabolically integrated proto-organelle whose genetic integration remains unresolved.

A membrane-bounded organelle that receives incoming material from primary endocytic vesicles that have been generated by clathrin-dependent and clathrin-independent endocytosis; vesicles fuse with the early endosome to deliver cargo for sorting into recycling or degradation pathways.

The volume enclosed by the membrane of an early endosome.

The lipid bilayer surrounding an early endosome.

A membrane-bounded intracellular vesicle formed by invagination of the plasma membrane around an extracellular substance. Endocytic vesicles fuse with early endosomes to deliver the cargo for further sorting.

The volume enclosed by the membrane of an endocytic vesicle.

The lipid bilayer surrounding an endocytic vesicle.

The irregular network of unit membranes, visible only by electron microscopy, that occurs in the cytoplasm of many eukaryotic cells. The membranes form a complex meshwork of tubular channels, which are often expanded into slitlike cavities called cisternae. The ER takes two forms, rough (or granular), with ribosomes adhering to the outer surface, and smooth (with no ribosomes attached).

The volume enclosed by the membranes of the endoplasmic reticulum.

The lipid bilayer surrounding the endoplasmic reticulum.

A vacuole to which materials ingested by endocytosis are delivered.

The volume enclosed by the membrane of an endosome.

The lipid bilayer surrounding an endosome.

The outermost lipid bilayer surrounding complex plastids in organisms that acquired their plastids through secondary endosymbiosis. This membrane is derived from the host cell's endomembrane system and is continuous with the rough endoplasmic reticulum and the outer nuclear envelope. In some species, the cytoplasmic face may be studded with ribosomes.

The lipid bilayer surrounding a vesicle transporting substances from the endoplasmic reticulum to the Golgi apparatus.

A vesicle filled with crystalline protein that shows sequence similarities with various esterases.

The volume enclosed by the esterosome membrane.

The lipid bilayer surrounding an esterosome.

A dense granule-like organelle of the apical complex of merozoites, released into the parasitophorous vacuole, mediating protease-dependent rupture and parasite exit from the infected erythrocyte.

A small pigmented organelle used in single-celled organisms to detect light.

A bacterial lipid-bounded iron-storage organelle that contains iron-, phosphorus- and oxygen-rich material and forms through Fez protein-dependent machinery.

Invagination of the plasma membrane from which a flagellum protrudes.

A vacuole within a parasite used for digestion of the host cell cytoplasm.

A vacuole that has both lytic and storage functions. The fungal vacuole is a large, membrane-bounded organelle that functions as a reservoir for small molecules and as the primary compartment for degradation.

The volume enclosed within the vacuolar membrane of the fungal-type vacuole.

The lipid bilayer surrounding the fungal-type vacuole.

A membrane-bounded organelle found in organisms from the order Kinetoplastida that houses the enzymes of glycolysis.

The volume enclosed by the glycosome membrane.

The membrane surrounding the glycosome.

The volume enclosed by the glyoxysome membrane.

The membrane surrounding the glyoxysome.

A specialized form of peroxisome that contains the enzymes of the glyoxylate pathway. The glyoxysome is found in some plant cells, notably the cells of germinating seeds.

A membrane-bound cytoplasmic organelle of the endomembrane system that further processes the core oligosaccharides (e.g. N-glycans) added to proteins in the endoplasmic reticulum and packages them into membrane-bound vesicles. The Golgi apparatus operates at the intersection of the secretory, lysosomal, and endocytic pathways.

Any vesicle associated with the Golgi complex and involved in mediating transport within the Golgi or between the Golgi and other parts of the cell.

The lipid bilayer surrounding a vesicle associated with the Golgi apparatus.

Any of the thin, flattened membrane-bounded compartments that form the central portion of the Golgi complex.

The lipid bilayer surrounding any of the thin, flattened compartments that form the central portion of the Golgi complex.

The volume enclosed by the membranes of any cisterna or subcompartment of the Golgi apparatus, including the cis- and trans-Golgi networks.

The lipid bilayer surrounding any of the compartments of the Golgi apparatus.

The lipid bilayer surrounding a hydrogenosome.

A spherical, membrane-bounded organelle found in some anaerobic protozoa, which participates in ATP and molecular hydrogen formation.

The volume enclosed by the hydrogenosome membrane.

An apicomplexan double-membrane pellicle structure formed by flattened vesicles beneath the plasma membrane.

A mitochondrial membrane-enclosed deposit compartment characterized in budding yeast that sequesters aggregated matrix proteins, often near the nucleus and separated from the remaining tubular mitochondrial network.

A prelysosomal endocytic organelle differentiated from early endosomes by lower lumenal pH and different protein composition. Late endosomes are more spherical than early endosomes and are mostly juxtanuclear, being concentrated near the microtubule organizing center.

The volume enclosed by the membrane of a late endosome.

The lipid bilayer surrounding a late endosome.

A membrane-bounded organelle of ciliated protozoan cells that contains polyploid copies of a portion of the cell's complete genome. Transcription of genes occurs in macronuclei. Some ciliate species may contain multiple macronuclei per cell.

A membrane-bounded organelle of magnetotactic bacteria enclosing a nanocrystal of a magnetic iron mineral — magnetite (Fe3O4) or greigite (Fe3S4). Magnetosomes are invaginations of the cytoplasmic membrane that are filled with iron, and are arranged into a chain along a cytoskeletal filament so that the cell behaves as a swimming compass needle.

The volume enclosed by the magnetosome membrane.

The lipid bilayer membrane surrounding a magnetosome.

A disk-like structure that appears at the periphery of a red blood cell infected by an apicomplexan parasite, characterized by a translucent lumen and an electron-dense coat of variable thickness; often appears to be tethered to the host cell membrane by fibrous connections with the erythrocyte cytoskeleton.

A cytoplasmic, membrane-bounded organelle in aerobic methanotrophic bacteria, built from intracytoplasmic membranes that house particulate methane monooxygenase and associated electron-transfer proteins for methane catabolism.

A small, elongated secretory organelle that forms part of the apical complex, located along the main axis of an apicomplexan parasite cell within the extreme apical region and at the periphery under the inner membrane complex. Of the specialized secretory compartments identified in apicomplexans, micronemes discharge their contents first, during initial contact of the parasite's apical pole with the host cell surface. Micronemal proteins function during parasite attachment and penetration into the target cell.

The volume enclosed by the microneme membrane.

The lipid bilayer surrounding a microneme.

A membrane-bounded organelle of ciliated protozoan cells that contains a diploid copy of the cell's complete genome. Sections of contiguous sequence in the macronucleus are often interrupted by internal eliminated sequences (IES), and may be permuted, in micronuclei. Genic transcription is not found in micronuclei. Some ciliate species may contain multiple micronuclei per cell.

A membrane-bounded posterior vesicle in a microsporidian spore that expands during germination and is implicated in polar-tube extrusion and sporoplasm expulsion.

Any of the inward folds of the mitochondrial inner membrane. Their number, extent, and shape differ in mitochondria from different tissues and organisms. They appear to be devices for increasing the surface area of the mitochondrial inner membrane, where the enzymes of electron transport and oxidative phosphorylation are found. Their shape can vary with the respiratory state of the mitochondria.

A tubular structure of relatively uniform size that connects a mitochondrial crista to the mitochondrial inner boundary membrane.

An inducible compartment characterized in budding yeast that remodels the outer mitochondrial membrane into multilamellar domains, selectively concentrates membrane-associated proteins, and can enclose cytosolic material.

The double lipid bilayer enclosing the mitochondrion and separating its contents from the cell cytoplasm; includes the intermembrane space.

The portion of the mitochondrial inner membrane that is not invaginated to form cristae and lies parallel to the outer membrane.

The inner, i.e. lumen-facing, lipid bilayer of the mitochondrial envelope. It is highly folded to form cristae.

The region between the inner and outer lipid bilayers of the mitochondrial envelope.

The gel-like material, with considerable fine structure, that lies in the matrix space, or lumen, of a mitochondrion. It contains the enzymes of the tricarboxylic acid cycle and, in some organisms, the enzymes concerned with fatty acid oxidation.

Either of the lipid bilayers that surround the mitochondrion and form the mitochondrial envelope.

The outer, i.e. cytoplasm-facing, lipid bilayer of the mitochondrial envelope.

A semiautonomous, self replicating organelle that occurs in varying numbers, shapes, and sizes in the cytoplasm of virtually all eukaryotic cells. It is notably the site of tissue respiration.

A double-membrane-bounded organelle that functions in iron-sulfur protein maturation; evolutionarily derived from mitochondria. The mitosome has been detected only in anaerobic or microaerophilic organisms that do not have mitochondria, such as Entamoeba histolytica, Giardia intestinalis and several species of Microsporidia. These organisms are not capable of gaining energy from oxidative phosphorylation, which is normally performed by mitochondria.

The mitosomal envelope comprises the inner and outer mitosomal membrane including the intermembrane space.

The inner membrane of a mitosome is the membrane which separates the mitosomal matrix from the intermembrane space.

The mitosomal intermembrane space is the space between inner and outer mitosomal membranes.

The matrix of a mitosome is the mitosomal internal spaces enclosed by the inner membrane.

The outer membrane of a mitosome is the mitosomal membrane facing the cytoplasm.

A small, threadlike secretory organelle that forms part of the apical complex and lies close to the subpellicular microtubules.

A small subcellular vesicle, surrounded by a membrane, in the pellicle of ciliate protozoans that discharges a mucus-like secretion.

A type of endosome in which regions of the limiting endosomal membrane invaginate to form internal vesicles; membrane proteins that enter the internal vesicles are sequestered from the cytoplasm.

A membrane-bounded vesicle inside a multivesicular body that forms when the limiting endosomal membrane buds inward and pinches into the lumen during multivesicular body sorting.

The multivesicular body compartment bounded by the multivesicular body membrane.

The lipid bilayer surrounding a multivesicular body.

A membrane-bounded nitrogen-fixing organelle derived from a UCYN-A cyanobacterium within a Braarudosphaera haptophyte; characterized in B. bigelowii by coordinated division and evidence for host-encoded protein import.

The double lipid bilayer that encloses the nucleus, separating its contents from the cytoplasm. It consists of an inner and outer nuclear membrane, with an intermembrane space (20-40 nm wide, also called the perinuclear space) between them. The envelope is supported by the nuclear lamina and contains nuclear pore complexes, which regulate molecular transport.

The region between the two lipid bilayers of the nuclear envelope.

The inner, i.e. lumen-facing, lipid bilayer of the nuclear envelope.

The volume enclosed by the nuclear inner membrane.

A reticulating double-membrane network characterized inside the nucleus of the dinoflagellate Polykrikos kofoidii. Its strands interconnect dinomitotic tunnels and the peripheral nuclear envelope, with regularly spaced swellings along the inner strands; the network is continuous with and forms part of the nuclear envelope.

The outer, i.e. cytoplasm-facing, lipid bilayer of the nuclear envelope.

A small, vestigial nucleus found in some plastids that derive from a eukaryotic endosymbiont. Observed in chlorarachniophytes and cryptomonads, which acquired their plastids from a green and red alga respectively.

A membrane-bounded organelle of eukaryotic cells in which chromosomes are housed and replicated. In most cells, the nucleus contains all of the cell's chromosomes except the organellar chromosomes, and is the site of RNA synthesis and processing.

A bacteroid-containing symbiosome in which the bacterial component is a genetically highly reduced cyanobacterium that is photosynthetically active

The inner, i.e. lumen-facing, of the two lipid bilayers surrounding an organellar chromatophore.

The region between the inner and outer lipid bilayers that surround an organellar chromatophore.

Either of the lipid bilayers that surround an organellar chromatophore.

The outer, i.e. cytoplasm-facing, of the two lipid bilayers surrounding an organellar chromatophore.

A thylakoid located in an organellar chromatophore

The volume enclosed by an organellar chromatophore thylakoid membrane.

The lipid bilayer membrane of any thylakoid within an organellar chromatophore.

A membrane-bounded vesicle found predominantly in Plasmodium female gametocytes, that becomes progressively more abundant as the gametocyte reaches full maturity. These vesicles lie beneath the subpellicular membrane of the gametocyte, and the release of their contents into the parasitophorous vacuole has been postulated to aid in the escape of gametocytes from the erythrocyte after ingestion by the mosquito.

A membrane-bounded host-cell vacuole in which an invading apicomplexan parasite resides and develops; its bounding parasitophorous vacuolar membrane is initiated during host-cell invasion and surrounds the intracellular parasite.

The parasitophorous vacuole compartment bounded by the membrane of the parasitophorous vacuole.

The membrane surrounding the parasitophorous vacuole.

The lipid bilayer that forms the second outermost membrane of complex plastids in organisms that acquired their plastids through secondary endosymbiosis. The periplastidial membrane is evolutionarily derived from the plasma membrane of the engulfed algal endosymbiont and together with the outer envelope membrane of the plastid defines the periplastidial compartment.

The volume contained within the membranes of a peroxisome; in many cells the matrix contains a crystalloid core largely composed of urate oxidase.

The lipid bilayer surrounding a peroxisome.

A small organelle enclosed by a single membrane, and found in most eukaryotic cells; it contains peroxidases and other enzymes involved in metabolic processes including free radical detoxification, lipid catabolism and biosynthesis, and hydrogen peroxide metabolism.

A membrane-bounded intracellular vesicle that arises from the ingestion of particulate material by phagocytosis.

The volume enclosed by a phagocytic vesicle membrane.

The lipid bilayer surrounding a phagocytic vesicle.

A membrane enriched in complexes formed of reaction centers, accessory pigments and electron carriers, in which photosynthetic reactions take place.

The lipid bilayer associated with a plasma membrane-derived chromatophore; surrounds chromatophores that form complete vesicles.

The internal lumen enclosed by a plasma membrane-derived bacterial thylakoid.

The pigmented membrane of a plasma membrane-derived thylakoid.

Any member of a family of organelles found in the cytoplasm of plants and some protists, which are membrane-bounded and contain DNA. Plant plastids develop from a common type, the proplastid.

The double lipid bilayer enclosing a plastid and separating its contents from the rest of the cytoplasm; includes the intermembrane space.

The inner, i.e. lumen-facing, lipid bilayer of the plastid envelope; also faces the plastid stroma.

The region between the inner and outer lipid bilayers of the plastid envelope.

Any lipid bilayer that surrounds a plastid or is part of the plastid envelope. Primary plastids (in plants, green algae, red algae, and glaucophytes) are surrounded by two membranes; complex plastids derived from secondary endosymbiosis are surrounded by three or four membranes.

The outer, i.e. cytoplasm-facing, lipid bilayer of the plastid envelope.

The ground substance of a plastid.

Any thylakoid within a plastid.

The volume enclosed by a plastid thylakoid membrane.

The lipid bilayer membrane of any thylakoid within a plastid.

A membrane-bounded organelle found in a microsporidian spore that swells with water and exerts pressure to rupture the polar cap and evert the polar tube.

A dinoflagellate membrane organelle connected to a flagellar canal, comprising sacs, tubules or collecting chambers with associated diverticula. Its wall includes an invaginated plasma membrane apposed to vacuolar membrane; the canal-connected lumen is not a sealed intracellular compartment.

A specialized membranous structure that extends from the photosynthetic thylakoid membrane into and transverses the matrix of a pyrenoid.

An organelle consisting of a network of tubules that functions in targeting molecules, such as receptors transporters and lipids, to the plasma membrane.

The volume enclosed by the membranes of a recycling endosome.

The lipid bilayer surrounding a recycling endosome.

A posterior, membrane-bounded endocytic organelle in Trypanosoma cruzi epimastigotes that receives internalized macromolecular cargo.

The volume enclosed by the membranes of a reservosome.

A matrix composed of planar membranes, vesicles and lipid inclusions within the reservosome.

A large, club-shaped secretory organelle that forms part of the apical complex of an apicomplexan parasite, and consists of a bulbous body and a narrow electron-dense neck that extends through the conoid at the apical tip of the parasite. The rhoptry necks serve as ducts through which the contents of the rhoptries are secreted after attachment to the host has been completed and at the commencement of invasion. Rhoptry proteins function in the biogenesis and host organellar association of the parasitophorous vacuole.

The volume enclosed by the rhoptry membrane.

The lipid bilayer surrounding a rhoptry.

Narrow, electron-dense part of the rhoptry that extends through the conoid at the apical tip of an apicomplexan parasite.

A cytoplasmic light-emitting compartment of certain dinoflagellates that produces bioluminescence upon acidification in the presence of oxygen.

A network of tubules and vesicles that is part of a contractile vacuole complex and participates in external water discharge during osmoregulation.

A membranous cellular structure that bears the photosynthetic pigments in photosynthetic bacteria and within chloroplasts.

The pigmented photosynthetic membrane of cyanobacteria and chloroplasts, enriched in photosystems, cytochrome b6f, ATP synthase, plastoquinone and glycolipids, where light-driven electron transport builds the proton motive force for photosynthetic ATP synthesis.

A ciliate offensive extrusome that stores toxic discharge material and ejects on prey contact to immobilize prey during raptorial feeding.

The network of interconnected tubular and cisternal structures located within the Golgi apparatus on the side distal to the endoplasmic reticulum, from which secretory vesicles emerge. The trans-Golgi network is important in the later stages of protein secretion where it is thought to play a key role in the sorting and targeting of secreted proteins to the correct destination.

The lipid bilayer surrounding any of the compartments that make up the trans-Golgi network.

The lipid bilayer surrounding a vesicle transporting substances between the trans-Golgi network and other parts of the cell.

A crystalline exocytotic organelle composed of small, acidic proteins existing primarily as disulphide-linked dimers. The trichocyst releases long filamentous proteins that capture predators in net-like structures to slow them down when the cell is disturbed.

The volume enclosed within the vacuolar membrane.

The lipid bilayer surrounding the vacuole and separating its contents from the cytoplasm of the cell.

A closed structure, found only in eukaryotic cells, that is completely surrounded by unit membrane and contains liquid material.

A peroxisome-derived dense-core vesicle of filamentous fungi that seals septal pores upon hyphal wounding.

A bacterial protein-shelled organelle in which a selectively permeable polyhedral shell encapsulates pathway enzymes to segregate segments of metabolism from the cytosol.

A bacterial microcompartment — a polyhedral, selectively permeable protein shell about 100–200 nm across — that encapsulates RuBisCO and carbonic anhydrase to concentrate CO2 around RuBisCO in cyanobacteria and many chemoautotrophs. Alpha-carboxysomes (cso genes) and beta-carboxysomes (ccm genes) evolved their shells and scaffolds independently.

The polyhedral protein coat of alpha- and beta-carboxysomes, built from BMC-H, BMC-T, and BMC-P shell proteins that enclose RuBisCO and carbonic anhydrase while controlling metabolite traffic between the lumen and cytosol.

A proteinaceous nanocompartment, 24 to 42 nm across, built from a single HK97-fold shell protein that self-assembles into an icosahedron. Cargo enzymes are packaged inside by a short targeting peptide that binds the shell interior; the commonest cargoes are ferritin-like iron-mineralising proteins and peroxidases.

An organelle found in bacteria consisting of a proteinaceous coat containing enzymes for the degradation of ethanolamine whose purpose is the protection of the rest of the cell from the toxic acetaldehyde product of the enzyme ethanolamine ammonia lyase.

An organelle found in bacteria consisting of a proteinaceous coat containing enzymes for the degradation of 1,2-propanediol whose purpose is the protection of the rest of the cell from the toxic propionaldehyde product of the enzyme diol dehydratase.

The region of a chloroplast to which the DNA is confined.

A sub-structure within the large single mitochondrion of kinetoplastid parasites and which is closely associated with the flagellar pocket and basal body of the flagellum.

The region of a mitochondrion to which the DNA is confined.

The non-membrane-bounded subcellular region in which a bacterial chromosome is compacted and organized with nucleoid-associated proteins while remaining dynamically coupled to transcription and replication.

A region of a plastid to which the DNA is confined.

A protein complex that catalyzes the transfer of a glucose group from UDP-glucose to a (1->3)-beta-D-glucan chain.

Enzyme complex consisting of four proteins: the two subunits of the hydroxylase component (hcaE and hcaF), a ferredoxin (hcaC) and a ferredoxin reductase (hcaD). Converts 3-phenylpropionic acid (PP) into cis-3-(3-carboxyethyl)-3,5-cyclohexadiene-1,2-diol (PP-dihydrodiol).

An ISWI complex that contains an ATPase subunit of the ISWI family (SNF2H in mammals, Isw2 in S. cerevisiae), an ACF1 homolog, and generally no other subunits, though Xenopus is an exception with a third non-conserved subunit. ACF plays roles in regulation of RNA polymerase II transcription and in DNA replication and repair.

An Escherichia coli tripartite multidrug efflux pump complex composed of AcrB inner-membrane RND transporters, AcrA periplasmic adaptor proteins, and the TolC outer-membrane channel that exports xenobiotics across the cell envelope.

An Escherichia coli RND-family cell-envelope efflux pump complex composed of AcrA, AcrD, and TolC subunits that exports aminoglycosides and other xenobiotic substrates across the cell envelope.

An Escherichia coli Resistance-Nodulation-Division-family cell-envelope efflux pump complex composed of AcrE, AcrF, and TolC subunits that exports acriflavines, indoles, and other xenobiotic substrates across the cell envelope.

A chromatin remodeling complex that regulates transcription via acetylation primarily of nucleosomal histones H3 and H2B. In budding yeast shares the histone acetylation (HAT) module of ADA2-GCN5-NGG1-SGF29 with the related SAGA complex.

A protein complex capable of alkanesulfonate monooxygenase activity. Involved in the utilization of alkanesulfonates as sulfur sources under conditions of sulfate or cysteine starvation, catalyzing the conversion of alkanesulfonates into aldehydes and sulfite. In E.coli the complex consists of a SsuD tetramer.

A complex of four polypeptides, comprising large and small DNA polymerase alpha subunits and two primase subunits, which are capable of catalyzing the synthesis of an RNA primer on the lagging strand of replicating DNA and the subsequent synthesis of a small stretch of DNA.

High affinity ammonium transporter complex that enables the transfer of ammonium from one side of a membrane to the other.

A heterotetrameric AP-type membrane coat adaptor complex that consists of beta1, gamma, mu1 and sigma1 subunits and links clathrin to the membrane surface of a vesicle; vesicles with AP-1-containing coats are normally found primarily in the trans-Golgi network. In at least humans, the AP-1 complex can be heterogeneric due to the existence of multiple subunit isoforms encoded by different genes (gamma1 and gamma2, mu1A and mu1B, and sigma1A, sigma1B and sigma1C).

A heterotetrameric AP-type membrane coat adaptor complex that consists of alpha, beta2, mu2 and sigma2 subunits, and links clathrin to the membrane surface of a vesicle, and the cargo receptors during receptor/clathrin mediated endocytosis. Vesicles with AP-2-containing coats are normally found primarily near the plasma membrane, on endocytic vesicles. In at least humans, the AP-2 complex can be heterogeneric due to the existence of multiple subunit isoforms encoded by different alpha genes (alphaA and alphaC).

A heterotetrameric AP-type membrane coat adaptor complex that consists of beta3, delta, mu3 and sigma3 subunits and is found associated with endosomal membranes. AP-3 does not appear to associate with clathrin in all organisms. In at least humans, the AP-3 complex can be heterogeneric due to the existence of multiple subunit isoforms encoded by different genes (beta3A and beta3B, mu3A and mu3B, and sigma3A and sigma3B).

An AP-type membrane coat adaptor complex that consists of beta4, epsilon, mu4 and sigma4 subunits and is found associated with membranes in the trans-Golgi network; it is not clear whether AP-4 forms clathrin coats in vivo.

An AP-type membrane coat adaptor complex that in humans consists of beta5, zeta, mu5 and sigma5 subunits and is found associated with membranes in the endosomes; it is not clear whether AP-5 forms clathrin coats in vivo.

Any of several heterotetrameric complexes that link clathrin (or another coat-forming molecule, as hypothesized for AP-3 and AP-4) to a membrane surface; they are found on coated pits and coated vesicles, and mediate sorting of cargo proteins into vesicles. Each AP complex contains two large (a beta and one of either an alpha, gamma, delta, or epsilon) subunits (110-130 kDa), a medium (mu) subunit (approximately 50 kDa), and a small (sigma) subunit (15-20 kDa).

A group of cytoskeletal structures and associated membrane-bounded organelles at the anterior end of apicomplexan parasites that supports host-cell attachment, penetration, and parasite proliferation.

Small membrane vesicle (< 1 um) that buds off a prokaryotic cell plasma membrane, able to carry proteins, phospholipids, lipopolysaccharides, nucleic acids, viruses, and more. Important in intercellular communication and pathogenesis; can exist within host cells.

A spherical, bilayered proteolipid vesicle released from gram-negative bacterial outer membranes.

A protein-DNA complex that forms at the bacterial oriC during the initial step of DNA replication and allows the origin to become competent, or 'licensed', for replication.

A bacterial outer-membrane beta-barrel protein assembly machine in which the BamA beta-barrel core and associated outer-membrane lipoproteins fold and insert beta-barrel proteins into the outer membrane.

A membrane-associated protein complex found in archaea that consists of sugar binding proteins assembled via a type IV pilin-like assembly system. The complex is located at the cell surface and functions in sugar uptake by facilitating the interaction between solute binding proteins and ABC transporters. The complex forms high molecular mass structures (400-600 kDa) that are integrated within or closely associated with the S-layer.

A conserved heterotrimeric protein complex that promotes histone H3 and H4 deposition onto newly synthesized DNA during replication or DNA repair; specifically facilitates replication-dependent nucleosome assembly with the major histone H3 (H3.1). In many species the CAF-1 subunits are designated p150, p60, and p48.

A multisubunit protein complex that binds to centromeric DNA and initiates kinetochore assembly. In yeast, this complex consists of four subunits, namely Ctf13p, Skp1p, Cep3p and Cbf2p.

The core of the CCR4-NOT complex. In Saccharomyces the CCR4-NOT core complex comprises Ccr4p, Caf1p, Caf40p, Caf130p, Not1p, Not2p, Not3p, Not4p, and Not5p.

The region of a cell that lies just beneath the plasma membrane and often, but not always, contains a network of actin filaments and associated proteins.

A cellular outgrowth formed during budding reproduction that remains connected to a mother cell while it grows into a new individual.

The constricted cellular region between a mother cell and its daughter bud in budding organisms.

Protein complex that has a role in determining cell polarity, found at the neck of a fungal bud before and during cytokinesis.

The distal region of a cellular bud opposite the mother-cell attachment site.

Protein complex that has a role in determining cell polarity, found at the tip of a growing fungal bud.

An extracellular membraneless organelle built around scaffoldin and dockerin-bearing enzymes that synergistically degrade insoluble plant-cell-wall polysaccharides.

A multisubunit ring-shaped complex that mediates protein folding in the cytosol without a cofactor.

Conserved heterotrimeric complex of PCNA-like proteins that is loaded onto DNA at sites of DNA damage.

An ISWI complex that contains an ATPase subunit of the ISWI family (SNF2H in mammals, Isw2 in S. cerevisiae), an ACF1 homolog, and additional small histone fold subunits (generally two of these, but Xenopus has only one and some additional non-conserved subunits). CHRAC plays roles in the regulation of RNA polymerase II transcription and in DNA replication and repair.

A membrane coat found on coated pits and some coated vesicles; consists of polymerized clathrin triskelions, each comprising three clathrin heavy chains and three clathrin light chains, linked to the membrane via one of the AP adaptor complexes.

The coat found on coated pits and the coated vesicles derived from coated pits; comprises clathrin and the AP-2 adaptor complex.

A clathrin coat found on an endocytic vesicle.

A clathrin coat found on a vesicle of the trans-Golgi network.

A part of the endomembrane system in the form of an invagination of a membrane upon which a clathrin coat forms, and that can be converted by vesicle budding into a clathrin-coated vesicle. Coated pits form on the plasma membrane, where they are involved in receptor-mediated selective transport of many proteins and other macromolecules across the cell membrane, in the trans-Golgi network, and on some endosomes.

A membrane vesicle coat whose core lattice is built from clathrin and that coats clathrin-coated vesicles.

A nuclear body that contains proteins involved in pre-mRNA 3'-end cleavage and polyadenylation, such as DDX1, CSTF2 and CPSFs, as well as the transcription factors TFIIE and TFIIF. Cleavage bodies are localized adjacent to Cajal bodies and are involved in mRNA3'-end processing.

A protein complex that contains the GINS complex, Cdc45p, and the heterohexameric MCM complex, and that is involved in unwinding DNA during replication.

A multisubunit tethering complex of the CATCHR family (complexes associated with tethering containing helical rods) that has a role in tethering vesicles to the Golgi prior to fusion. Composed of 8 subunits COG1-8.

A kinetochore multiprotein complex that bridges the subunits that are in contact with centromeric DNA and the subunits bound to microtubules during kinetochore assembly. In yeast, consists of Ctf19p, Okp1p, Mcm21p, and Ame1p.

A COPI membrane vesicle coat complex found associated with Golgi membranes; it forms on COPI-coated vesicles that mediate Golgi-to-endoplasmic-reticulum retrograde transport.

A COPII coat protein complex that assembles on endoplasmic-reticulum membranes to bud COPII-coated ER-to-Golgi transport vesicles; in budding yeast it contains Sar1p, Sec23p, Sec24p, Sec13p, and Sec31p.

A protein-DNA complex containing at least one DNA helicase and one primase. Can also contain associated proteins. The helicase component continues to unwind the double-stranded DNA (dsDNA) and the primase component synthesizes a RNA primer during initiation or restart of replication.

The core TFIIH complex when it is part of the general transcription factor TFIIH.

The core TFIIH complex when it is part of the nucleotide-excision repair factor 3 (NEF3).

A multimeric protein complex that acts as an endosomal tethering complex (CORVET = class C core vacuole/endosome tethering) by cooperating with Rab GTPases to capture endosomal vesicles and trap them prior to the action of SNAREs; the complex is involved in endo-lysosomal biogenesis and required for transport between endosome and vacuole. The Saccharomyces cerevisiae complex contains Vps8p, Vps3p, Pep5p, Vps16p, Pep3p, and Vps33p.

A WDR1-containing Cullin4-DDB1 protein complex characterized in procyclic Trypanosoma brucei. The named CRL4WDR1 association participates in regulation of TbPLK protein turnover; its complete catalytic composition and direct ubiquitination of TbPLK have not been established.

A heptameric complex related to replication factor C, which loads the DNA polymerase processivity factor proliferating cell nuclear antigen (PCNA) onto DNA and plays a vital role in chromosome cohesion. In Saccharomyces the subunits are known as Ctf18p, Rfc2p, Rfc3p, Rfc4p, Rfc5p, Dcc1p, and Ctf8p.

A cullin-RING protein complex defined by the Cullin-E scaffold, experimentally characterized in Trypanosoma brucei by co-isolation with Rbx1, Skp1.2 and kelch-domain proteins. The associated kelch proteins are candidate client-recognition subunits; simultaneous occupancy and fixed stoichiometry have not been established.

A protein complex that is involved in the Cvt pathway. In budding yeast, the Cvt complex consists of multimers of preApe1p.

Stable, specialized structure for the ingestion of food by the cell into phagosomes.

A large protein complex, containing around 8-10 subunits in yeast, including Duo1p, Dam1p, Dad1p and Ask1p. The complex forms part of the outer kinetochore, associates with microtubules when the kinetochore attaches to the spindle, and plays a role in spindle attachment, chromosome segregation and spindle stability.

A heterodimeric protein complex required for the activation of DNA replication origins; comprises a catalytic subunit and a regulatory subunit (in Saccharomyces, Cdc7p and Dbf4p, respectively); complexes identified in other species generally contain proteins related to the Saccharomyces proteins.

A multimeric DNA polymerase enzyme complex whose subunit composition differs among species and that functions in DNA replication, mismatch repair, and excision repair; in Saccharomyces cerevisiae, DNA polymerase delta contains Pol3, Pol31, and Pol32 subunits.

A homotetrameric protein complex consisting of a symmetrical pair of DiaA homodimers. Facilitates DnaA binding to the origin of replication during replication initiation.

The anterior most point of a dinoflagellate hypocone.

A horn-shaped dinoflagellate antapex found in thecate species.

The anterior most point of a dinoflagellate epicone.

A cell surface furrow (or groove) found on a dinoflagellate apex. It typically loops around the apex.

A horn-shaped dinoflagellate apex found in thecate species.

A cell surface furrow that wraps around a dinoflagellate cell; the transverse flagellum lies in it.

The part of a dinoflagellate cell above the cingulum; also referred to as the anterior portion of a dinoflagellate cell. It is separated from the hypocone by the cingulum.

The part of a dinoflagellate cell below the cingulum; also referred to as the posterior portion of a dinoflagellate cell. It is separated from the epicone by the cingulum.

A dinoflagellate sulcus that extends all the way to the posterior end of the cell (also known as antapex). The presence of a sulcal notch makes the dinoflagellate hypocone appear bilobed.

A cell surface furrow that occurs on the ventral side of a dinoflagellate cell. It partially houses the longitudinal flagellum. The sulcus intersects with the cingulum on the ventral side of a dinoflagellate cell.

DNA gyrase complex is a bacterial GyrA2-GyrB2 type IIA topoisomerase complex that uses ATP hydrolysis to introduce negative supercoils into DNA and can also relax positive supercoils.

A subcomplex of the DNA polymerase III holoenzyme which is responsible for tethering the catalytic subunit of DNA polymerase to DNA during high-speed replication. The complex is homodimeric in prokaryotes, and homotrimeric in other species.

A dimer composed of the chi and psi subunits which is a subassembly of the DNA polymerase III clamp loader complex and serves as a bridge between the DnaX complex and the single-stranded DNA-binding protein (SSB).

A heptamer that includes the tau and gamma products of the dnaX gene and the chi/psi subcomplex. Confers structural asymmetry that allows the polymerase to replicate both leading and lagging strands.

A DNA polymerase III holoenzyme complex organized into a Pol III core, a beta sliding-clamp processivity factor, and a clamp-loader complex that together support processive DNA replication.

A DNA polymerase III core subassembly made of alpha, epsilon and theta subunits that provides polymerase and 3'-5' exonuclease proofreading activities within the DNA polymerase III holoenzyme.

A conserved heterotrimeric eukaryotic single-stranded-DNA-binding complex, also known as replication protein A, that supports DNA replication, repair and recombination.

A complex that loads the DNA polymerase processivity factor proliferating cell nuclear antigen (PCNA) onto DNA, thereby permitting processive DNA synthesis catalyzed by DNA polymerase. In eukaryotes the complex consists of five polypeptides.

A bacterial type IIA topoisomerase complex composed of ParC and ParE subunits that can relax supercoiled DNA and supports chromosome segregation.

A protein-DNA complex containing a tetramer of DiaA attached to multiple DnaA molecule bound to oriC DNA. Regulates timely initiation of chromosomal replication during the cell cycle by stimulating assembly of DnaA-oriC complexes, conformational changes in ATP-DnaA initiation complexes, and unwinding of oriC duplex DNA.

A protein-DNA complex consisting of the helicase loading complex DnaB-DnaC bound to the DNA-bound DNA replication initiation protein DnaA. Essential for DNA replication initiation.

A protein complex that negatively regulates strand-opening at the origin of replication, thereby interfering with replication initiation. This complex is thought to be involved in the regulation of replication under oxidative stress conditions. In E. coli, this complex is composed of DnaA and Dps.

A protein complex that inactivates the function of DnaA by inhibiting the phosphorylation of DnaA-ADP to DnaA-ATP and thereby preventing multiple events of replication initiation. In E. coli, this complex is composed of DnaA and Hda.

A protein-DNA complex containing DNA-bound DnaA attached to HU. HU is a dimer encoded by two closely related genes. Essential for the initiation of replication in bacteria; stimulates the DnaA-dependent unwinding of oriC.

A protein complex that inhibits unwinding of DNA at the origin of replication and assembly of the pre-primosome. In E. coli, this complex is composed of DnaA and of the ribosomal protein L2.

A protein-DNA complex containing the initiator protein DnaA bound to high-affinity recognition sites in the unique origin of replication, oriC. DnaA-oriC binding is the first step in assembly of a bacterial pre-replicative complex (pre-RC) and is responsible for the timely initiation of replication once per cell cycle.

A protein complex containing homohexameric DNA helicase DnaB, and the DNA helicase loader DnaC. The helicase loader DnaC delivers DnaB to the chromosomal origin (oriC).

A protein-DNA complex consisting of the helicase loading complex DnaB-DnaC, replication restart proteins DnaT, PriA and PriB, and associated DNA. Involved in the restart of DNA replication after a stalled replication fork has been repaired.

A protein-DNA complex consisting of the helicase loading complex DnaB-DnaC, replication restart proteins DnaT, PriA and PriC, and associated DNA. Involved in the restart of DNA replication after a stalled replication fork has been repaired.

A protein-DNA complex consisting of the helicase loading complex DnaB-DnaC, replication restart proteins Rep and PriC, and associated DNA. Involved in the restart of DNA replication after a stalled replication fork has been repaired.

A protein complex containing homohexameric DnaB helicase, and DnaG (a primase). Facilitates the unwinding of double-stranded DNA and the synthesis of RNA primer sequences during DNA replication and repair in Prokaryotes.

A homohexameric protein complex that possesses DNA helicase activity; functions during DNA replication and repair.

A multisubunit tethering complex, i.e. a protein complex involved in mediating the initial interaction between vesicles and the membranes with which they fuse, that is involved in trafficking from the Golgi apparatus to the ER. In Saccharomyces cerevisiae the Dsl1p complex contains Dsl1p, Tip20p, and Sec39p.

A protein complex that forms part of SAGA-type complexes SAGA and SLIK, and mediates deubiquitination of histone H2B. In S. cerevisiae, the DUBm consists of the proteins Ubp8p, Sgf11p, Sus1p, and Sgf73p.

A protein complex that is involved in the MEP pathway of IPP biosynthesis. It catalyzes the NADP-dependent rearrangement and reduction of 1-deoxy-D-xylulose-5-phosphate (DXP) to 2-C-methyl-D-erythritol 4-phosphate (MEP).

A cell part that is composed of the eisosome membrane or MCC domain, a furrow-like plasma membrane sub-domain and associated integral transmembrane proteins, and the proteins (eisosome filaments) that form a scaffolding lattice on the cytoplasmic face. Eisosomes broadly affect overall plasma membrane organization.

A cryptophyte extrusive organelle that discharges proteinaceous paracrystalline ribbons or filaments built in part from small ejectisin polypeptides.

A pentameric replication factor C-like complex that unloads the proliferating cell nuclear antigen DNA clamp from chromatin and supports telomere length regulation and genome stability in Saccharomyces.

A heterohexameric protein complex composed two discrete heterotrimeric subcomplexes that is involved in modification of wobble nucleosides in tRNA.

A transmembrane protein complex in the endoplasmic reticulum membrane that promotes insertion of newly synthesized proteins into the ER membrane.

An Escherichia coli MFS-family cell-envelope efflux pump complex composed of EmrA, EmrB, and TolC subunits that exports hydrophobic xenobiotics across the inner and outer membranes.

A transmembrane protein complex capable of transporting positively charged hydrophobic drugs across the plasma membrane thereby involved in conferring resistance to a wide range of toxic compounds (e.g. methyl viologen, ethidium bromide and acriflavine). It is commonly found in bacteria. In E. coli it forms a homodimer.

An Escherichia coli MFS-family cell-envelope efflux pump complex composed of EmrK, EmrY, and TolC subunits that exports xenobiotics, including antimicrobial compounds, from the cell.

An endoplasmic reticulum membrane-associated complex involved in the translocation of proteins that are targeted to the ER. In yeast, this complex consists of two subcomplexes, namely, the Sec61 complex and the Sec62/Sec63 complex.

A heterotetrameric DNA polymerase complex that catalyzes processive DNA synthesis in the absence of PCNA, but is further stimulated in the presence of PCNA. The complex contains a large catalytic subunit and three small subunits, and is best characterized in Saccharomyces, in which the subunits are named Pol2p, Dpb2p, Dpb3p, and Dpb4p. Some evidence suggests that DNA polymerase epsilon is the leading strand polymerase; it is also involved in nucleotide-excision repair and mismatch repair.

A protein complex that links the endoplasmic reticulum with mitochondria and may have a role in promoting exchange of calcium and phospholipids between the two organelles.

A protein complex required for the recycling of Golgi proteins, formation of lumenal membranes and sorting of ubiquitinated proteins into those membranes. This complex includes Vps1p and Hse1p in yeast and the Hrs and STAM proteins in mammals.

An endosomal sorting complex involved in membrane fission processes related to sorting of multivesicular bodies (MVB) in the endocytic pathway, cytokinesis and viral budding among other processes.

An endosomal sorting complex required for transport. It consists of the class E vacuolar protein sorting (Vps) proteins and interacts with ubiquitinated cargoes.

An endosomal sorting complex required for transport and functions downstream of ESCRT I complex. It consists of the class E vacuolar protein sorting (Vps) proteins and is required for the membrane recruitment of ESCRT III complex and binds to ubiquitinated cargoes.

A complex with membrane scission activity that plays a major role in many processes where membranes are remodelled - including endosomal transport (vesicle budding), nuclear envelope organisation (membrane closure, mitotic bridge cleavage), and cytokinesis (abscission).

An ESCRT complex that has AAA-ATPase activity and is involved in ESCRT-mediated intralumenal vesicle formation and the final stages of cytokinesis. The complex catalyzes disassembly of the ESCRT III filament around the neck of the budding vesicle in an ATP-driven reaction, resulting in membrane scission and recycling of the ESCRT III components back to the cytosol. In yeast, it is formed by the AAA ATPase Vps4 and its cofactor Vta1.

A vesicle tethering complex peripherally associated with the plasma membrane that determines where vesicles dock and fuse. At least eight complex components are conserved between yeast and mammals.

Exodeoxyribonuclease V complex is a RecB-RecC-RecD enzyme complex that combines ATP-dependent DNA unwinding with exonucleolytic cleavage of DNA to produce 5'-phosphooligonucleotides.

A protein complex that acts as a selective cargo adaptor mediating the selective transport of specific membrane proteins from the trans-Golgi network (TGN) to the plasma membrane.

A histone chaperone complex that facilitates nucleosome disassembly and reassembly upon DNA or RNA polymerase passage.

A protein complex capable of FMN reductase activity. Reduces FMN to FMNH2 in a NAD(P)H-dependent manner. In E.coli, consists of a SsuE dimer.

A DNA polymerase complex consisting of a large subunit, responsible for the catalytic activities, and a small accessory subunit. Functions in the replication and repair of mitochondrial DNA.

A quatrefoil tethering complex required for retrograde traffic from the early endosome back to the late Golgi and biogenesis of cytoplasmic vesicles.

A GTPase-activating protein (GAP) complex that regulates TORC1 signaling by interacting with the Rag GTPase. In human, the GATOR1 complex consists of DEPDC5, NPRL2, and NPRL3. In S. cerevisiae, this complex is referred to as SEACIT and contains the Iml1p, Npr2p, and Npr3p proteins.

A multiprotein subcomplex of the GATOR complex that regulates TORC1 signaling by interacting with the Rag GTPase. In human, this complex consists of WDR24, WDR59, MIOS, SEH1L, and SEC13. In S. cerevisiae, this complex is referred to as SEACAT and contains the Sea2p, Sea3p, Sea4p, Seh1p, Sec13p proteins.

Nuclear bodies frequently found near or associated with Cajal bodies (also called coiled bodies or CBs). Gemini of coiled bodies, or 'gems', are similar in size and shape to CBs, and often indistinguishable under the microscope. Unlike CBs, gems do not contain small nuclear ribonucleoproteins (snRNPs); they contain a protein called survivor of motor neurons (SMN) whose function relates to snRNP biogenesis. Gems are believed to assist CBs in snRNP biogenesis, and to play a role in the etiology of spinal muscular atrophy (SMA).

An endoplasmic reticulum protein-containing complex that is conserved in eukaryotes and mediates the insertion of tail-anchored proteins into the ER membrane.

A heterotetrameric protein complex that associates with replication origins, where it is required for the initiation of DNA replication, and with replication forks.

A protein complex composed of at least GAP45 (gliding-associated protein), GAP50 and myosin heavy and light chains. Anchored via GAP50 to the inner membrane complex of motile and invasive forms of apicomplexan parasites and regulates parasite gliding motility and invasion of host cells.

A NADPH-dependent glutamate synthase protein complex that possesses glutamate synthase (NADPH) activity.

A glycine-cleavage multienzyme protein complex that reversibly oxidizes glycine through L-, P-, H-, and T-protein components.

A protein complex that possesses glycine reductase activity and is usually built from selenoprotein A, selenoprotein B, and protein C subunits.

A multisubunit membrane protein complex that attaches preassembled glycosylphosphatidylinositol anchors to proteins.

Bacterial chaperonin complex consisting of a heptameric 10kDa chaperonin subunit GroES and a tetradecameric (2x7) 60kDa chaperonin subunit GroEL. The 60kDa subunit possesses ATPase activity while the holo-enzyme is responsible for the correct folding of proteins.

A heterodimer GTPase complex. In S. cerevisiae, this complex contains Gtr1p and Gtr2p proteins.

A tetrameric histone deacetylase complex that contains a Class II deacetylase catalytic subunit. In S. cerevisiae it is composed of two Hda1p subunits along with Hda2p and Hda3p.

A protein complex involved in inactivating the function of DnaA and thereby preventing multiple events of replication initiation. In E. coli, this complex is composed of the beta clamp (DnaN) and Hda.

A protein complex proposed to be involved in replication-independent nucleosome assembly, by promoting histone deposition onto DNA. For example, in Saccharomyces, the complex contains Hir1p, Hir2p, Hir3p, and Hpc2p.

A polar extracellular adhesive matrix of Caulobacter vibrioides composed of secreted holdfast polysaccharide that is anchored at the old cell pole or stalk tip and enables irreversible surface attachment.

A multimeric protein complex that associates with the vacuolar membrane, late endosomal (multivesicular body) and lysosomal membranes. HOPS is a tethering complex involved in vesicle fusion.

An oligomeric mitochondrial matrix chaperone assembly built from Hsp78-type subunits and involved in ATP-dependent solubilization of aggregated proteins.

Protein complex that has a role in determining cell polarity, found at the tip of a growing fungal hypha.

Protease complex of the mitochondrial inner membrane whose catalytic residues lie on the intermembrane space side of the inner membrane; involved in mitochondrial protein turnover. Contains a subunit belonging to the AAA family of ATP-dependent metalloproteases.

A multisubunit protein complex that contains the Ino80p ATPase; exhibits chromatin remodeling activity.

An Isw1 complex that binds DNA and has nucleosome-stimulated ATPase activity. In S. cerevisiae, contains an Isw1p ATPase subunit in complex with Ioc3p.

An Isw1 complex that binds DNA and has nucleosome-stimulated ATPase activity. In S. cerevisiae, contains an Isw1p ATPase subunit in complex with Ioc2p and Ioc4p.

A multisubunit complex that is located at the centromeric region of DNA and provides an attachment point for the spindle microtubules.

Heterodimeric protein complex composed of a 70 kDa and a 80 kDa subunit, binds DNA through a channel formed by the heterodimer. Functions in DNA double stranded break repair, chromosome maintenance, transcription regulation, V(D)J recombination, and activation of DNA-PK.

A protein-containing complex that functions to transport lipopolysaccharide from its site of synthesis at the cytoplasmic membrane across the periplasm to the outer membrane in an ATP-dependent manner.

An Escherichia coli inner-membrane ABC transporter complex composed of one LolC transmembrane subunit, two LolD ATP-binding subunits, and one LolE transmembrane subunit that uses LolD ATP hydrolysis to release outer membrane-specific lipoproteins from the inner membrane for periplasmic trafficking.

A nuclear body that is enriched in the lymphoid cell-specific protein LYSp100B; LANDs are globular, electron-dense structures and are morphologically distinct from the annular structures characteristic of PML bodies.

Protease complex of the mitochondrial inner membrane that is involved in mitochondrial protein turnover and in processing of proteins imported into mitochondria.

The MacAB-TolC complex is a macrolide transporter complex found in E.coli and related gram-negative bacteria. Its transport activity is specific to macrolide compounds containing 14- and 15-membered lactones. It consists of the dimeric inner membrane ATPase MacB, the hexameric, periplasmic membrane fusion protein MacA and the trimeric outer membrane factor TolC.

The apex of the mating projection in unicellular fungi exposed to mating pheromone; site of polarized growth.

Protein complex that has a role in determining cell polarity, found at the tip of the mating projection in unicellular fungi exposed to mating pheromone.

A hexameric protein complex required for the initiation and regulation of DNA replication.

An Escherichia coli Resistance-Nodulation-Division-family cell-envelope efflux pump complex composed of MdtA, MdtB, MdtC, and TolC subunits that exports novobiocin, bile salts, quinolones, fosfomycin, detergents, myricetin, zinc, and other substrates from the cell.

A protein complex containing two transmembrane subunits; a MdtB dimer and one unit of MdtC. Capable of exporting substrates across the cell membrane. Involved in conferring antibiotic resistance of Gram-negative bacteria by transporting drugs across the membrane.

A polarized nuclear chromosome assembly in which telomeric ends and their anchoring proteins cluster within a restricted region of the nuclear envelope during meiotic prophase. Characterized in fission and budding yeast, it organizes chromosome ends while chromosome arms extend into the nucleus; its duration and tethering machinery differ between species.

Any of several different proteinaceous coats that can associate with membranes. Membrane coats include those formed by clathrin plus an adaptor complex, the COPI and COPII complexes, and possibly others. They are found associated with membranes on many vesicles as well as other membrane features such as pits and perhaps tubules.

An ATP-binding cassette (ABC) transporter complex that is capable of methionine-importing activity. An example is the bacterial MetNIQ methionine transporter, that consists of the dimeric ATPase subunit MetN located at the cytoplasmic side of the plasma membrane and the dimeric transmembrane subunit MetI. MetQ is regarded as the periplasmic methionine-binding chaperon subunit, and is capable of transporting methionine from the periplasm into the cytoplasm in an ATP-dependent manner.

The chemoreceptor array: a hexagonal lattice of trimers-of-dimers of methyl-accepting chemotaxis proteins, held at the membrane by the CheA kinase and the CheW coupling protein. The array is the cell's sensory organ, and its geometry — a 12 nm hexagonal spacing conserved across bacteria and archaea — is what gives chemotaxis its cooperativity and gain.

A mitochondrial intermembrane-space-spanning assembly that couples inner-membrane MICOS to outer-membrane SAM and includes a conserved DNAJC11-related protein and metaxin 1.

A mitochondrial inner-membrane MICOS subcomplex containing Mic10, Mic12, Mic26 and Mic27, organized around Mic10 oligomers and involved in crista architecture.

A heteromeric MICOS subcomplex composed of Mic60 and Mic19 that couples protein assembly to mitochondrial inner-membrane remodeling and crista-junction organization.

Mitochondrial inner membrane complex involved in maintenance of crista junctions, inner membrane architecture, and formation of contact sites to the outer membrane.

A protein complex located in the mitochondrial outer membrane that functions as an insertase, mediating the insertion of alpha-helical proteins from the cytosol into the outer membrane. Client proteins are usually single- and multi-span proteins that include components of the TOM complex.

A multiprotein kinetochore subcomplex that binds to centromeric chromatin and forms part of the outer kinetochore. It helps to recruit outer kinetochore subunits that will bind to microtubules. In humans, it consists of MIS12, DSN1, NSL1 and PMF1.

Protease complex of the mitochondrial inner membrane, consisting of at least two subunits, involved in processing of both nuclear- and mitochondrially-encoded proteins targeted to the intermembrane space.

An oligomeric mitochondrial matrix protease assembly built from Lon-family subunits that combine AAA+ ATPase and serine-protease domains to process protein substrates.

A biochemically isolatable protein-lipid assembly of the mitochondrial inner membrane characterized in Saccharomyces cerevisiae. MIMAS brings together metabolite carriers, dehydrogenases, respiratory-chain biogenesis factors and phospholipid enzymes, with stability dependent on phosphatidylethanolamine production.

A large complex of the mitochondrial outer membrane that mediates transport of proteins into all mitochondrial compartments.

Inner-mitochondrial-membrane macromolecular complex composed of repeating prohibitin 1 and prohibitin 2 heterodimeric subunits.

A ribonuclease P complex located in the mitochondrion of a eukaryotic cell, where it catalyzes the 5' endonucleolytic cleavage of precursor tRNAs to yield mature tRNAs. The subunit composition of mitochondrial ribonuclease P complexes varies between species. The complex contains a single RNA molecule and a single protein molecule in yeast (PMID:12045094), but comprises three proteins and lacks an RNA component in humans.

An Escherichia coli inner-membrane ABC transporter complex composed of MlaE, MlaF, MlaD, and MlaB subunits that participates in phospholipid transport during maintenance of outer-membrane lipid asymmetry.

A dimeric protein complex containing two ModE subunits. Binds directly to DNA to regulate transcription, and is involved in (positively and negatively) regulating various aspects of molybdenum metabolism.

A protein complex required for clamping microtubule binding sites, ensuring orientation of sister kinetochores to the same pole (mono-orientation) during meiosis I.

A protein complex that forms a subcomplex of the 90S preribosome. In S. cerevisiae, it is composed of Mpp10p, Imp3p and Imp4p.

Trimeric protein complex that possesses endonuclease activity; involved in meiotic recombination, DNA repair and checkpoint signaling. In Saccharomyces cerevisiae, the complex comprises Mre11p, Rad50p, and Xrs2p; complexes identified in other species generally contain proteins orthologous to the Saccharomyces cerevisiae proteins.

A protein complex that consists of an RNA 5' triphosphatase and a guanyl transferase (Cet1p and Ceg1p in S. cerevisiae; Pct1 and Ceg1 in S. pombe) and is involved in mRNA capping.

An ATP-binding cassette (ABC) transporter complex made up of a dimer of MsbA. Facilitates the export across the plasma membrane of, amongst others, lipid A and lipopolysaccharide. In contrast to most ABC transporter complexes, each chain of the homodimer contains both the transmembrane domain (TMD) and the cytoplasmic ATP-binding domain (NBD).

A protein complex that can catalyze the acetylation of lysine at position 14 in histone H3, and contains Mst2 as the catalytic subunit. In fission yeast, contains at least Mst2, Nto1, Ptf2, Ptf1 and Eaf6.

A homodimeric mismatch repair complex involved in binding to and correcting insertion/deletion mutations.

A conserved complex that catalyzes the transfer of an acetyl group to an N-terminal Ser, Ala, Gly, or Thr residue of a protein acceptor molecule. In Saccharomyces the complex includes Nat1p and Ard1p, and may contain additional proteins.

A conserved complex that catalyzes the transfer of an acetyl group to the N-terminal residue of a protein acceptor molecule that has a Met-Glu, Met-Asp, Met-Asn, or Met-Met N-terminus. In Saccharomyces the complex includes Nat3p and Mdm20p.

A conserved complex that catalyzes the transfer of an acetyl group to the N-terminal residue of a protein acceptor molecule that has a Met-Ile, Met-Leu, Met-Trp, or Met-Phe N-terminus. In Saccharomyces the complex includes Mak3p, Mak10p, and Mak31p.

A protein complex conserved among eukaryotes that forms part of the kinetochore and plays an essential role in forming stable kinetochore-microtubule attachments. The complex contains proteins known in several species, including budding and fission yeasts, as Ndc80p, Nuf2p, Spc24p, and Spc25p. In vertebrates it is part of the outer plate of the kinetochore.

A heterodimer associated with 90S and 66S preribosomes. Predominantly, but not exclusively, nucleolar; involved in ribosomal large subunit biogenesis.

A heterodimer associated with 66S preribosomes; predominantly nucleoplasmic, but also locates to the nucleolus; involved in ribosomal large subunit biogenesis.

A heterodimer associated with precursors of the eukaryotic small ribosomal subunit, including the 90S preribosome; involved in small subunit biogenesis.

A NuA3 complex that catalyzes the acetylation of Histone H3. In S. cerevisiae, this complex consists of Eaf6p, Nto1p, Sas3p, Taf14p, Yng1p and associates with H3K4me3 using Yng1p.

A NuA3 complex that catalyzes the acetylation of Histone H3. In S. cerevisiae, this complex consists of Eaf6p, Nto1p, Sas3p, Taf14p, Pdp3 and associates with H3K4me3 via Pdp3p.

A complex having histone acetylase activity on chromatin, as well as ATPase, DNA helicase and structural DNA binding activities. The complex is thought to be involved in double-strand DNA break repair. Subunits of the human complex include HTATIP/TIP60, TRRAP, RUVBL1, BUVBL2, beta-actin and BAF53/ACTL6A. In yeast, the complex has 13 subunits, including the catalytic subunit Esa1 (homologous to human Tip60).

A chromosome that encodes the nuclear genome and is found in the nucleus of a eukaryotic cell during the cell cycle phases when the nucleus is intact.

An nuclear body involved in nuclear mRNA surveilllance. Contains at least Mmi1, or an ortholog of it, and the nuclear exosome.

A multisubunit complex that is located at the replication origins of a chromosome in the nucleus.

A membrane-embedded eukaryotic protein complex that forms a discrete pore in the nuclear envelope where the inner and outer nuclear membranes join and mediates exchange between the nucleus and cytoplasm.

A central eukaryotic nuclear pore substructure composed of FG-repeat channel nucleoporins that forms the selective transport path for RNAs, proteins, and small molecules.

Filamentous extensions on the cytoplasmic face of the eukaryotic nuclear pore complex.

A ring-shaped eukaryotic nuclear pore subcomplex built from inner-ring scaffold nucleoporins around the central transport channel.

A eukaryotic nuclear pore substructure made of linker nucleoporins that connect central transport-channel FG nucleoporins with core nuclear-pore scaffold modules.

A filamentous, cage-like assembly on the nuclear face of the nuclear pore complex.

A ring-shaped eukaryotic nuclear pore subcomplex built from outer-ring coat nucleoporins on the cytoplasmic and nucleoplasmic faces of the nuclear pore scaffold.

A dense, non-membrane-bounded body in the eukaryotic nuclear lumen that concentrates ribosomal DNA transcription, pre-rRNA processing, and early ribosomal subunit assembly.

One of several protein complexes involved in nucleotide-excision repair; possesses DNA damage recognition and endodeoxynuclease activities. In S. cerevisiae, it is composed of Rad1p, Rad10p, and Rad14p; in human the subunits are ERCC4/XPF, ERCC1 and XPA, respectively.

One of several protein complexes involved in nucleotide-excision repair; possesses damaged DNA binding activity. In S. cerevisiae, it is composed of Rad4p and Rad23p.

One of several protein complexes involved in nucleotide-excision repair; possesses endodeoxynuclease and DNA helicase activities. In S. cerevisiae, it is composed of Rad2p and the core TFIIH-Ssl2p complex (core TFIIH is composed of Rad3p, Tfb1p, Tfb2p, Ssl1p, Tfb4p and Tfb5p. Note that Ssl2p is also called Rad25p).

One of several protein complexes involved in nucleotide-excision repair; possesses DNA damage recognition and DNA-dependent ATPase activities. In S. cerevisiae, it is composed of Rad7p and Rad16p.

Complex basket- or funnel-like structure used by the cell to collect food and channel it to the cytostome; includes specialized sub-structures made up of closely-spaced cilia and underlying basal bodies and fibrillar systems.

The region of a kinetochore most external to centromeric DNA; this outer region mediates kinetochore-microtubule interactions.

A mitochondrial matrix-side protein complex associated with the TIM23 inner-membrane translocase that uses ATPase motor activity to drive protein import into the mitochondrial matrix.

A complex that possesses poly(A)-specific ribonuclease activity; catalyzes the message-specific shortening of mRNA poly(A) tails. Contains at least two subunits, known as Pan2p and Pan3p in Saccharomyces.

A jumbo-bacteriophage protein-shelled compartment that assembles in infected bacterial cells, surrounds replicating phage DNA, and spatially separates phage genome replication and transcription from bacterial translation.

Punctate structures proximal to the endoplasmic reticulum which are the sites where the Atg machinery assembles upon autophagy induction.

A PaaA/PaaB/PaaC/PaaE multicomponent monooxygenase complex that catalyzes the NADPH- and oxygen-dependent epoxidation of phenylacetyl-CoA to 2-(1,2-epoxy-1,2-dihydrophenyl)acetyl-CoA.

A heterotrimeric H4/H2A histone acetyltransferase complex with a substrate preference of chromatin over free histones. It contains a subset of the proteins found in the larger NuA4 histone acetyltransferase complex; for example, the S. cerevisiae complex contains Esa1p, Yng2p, and Epl1p.

A class of nuclear body; they react against SP100 auto-antibodies (PML, promyelocytic leukemia); cells typically contain 10-30 PML bodies per nucleus; alterations in the localization of PML bodies occurs after viral infection.

A fungal cell-polarity protein complex that localizes to sites of polarized growth and directs localized actin-filament assembly, including the Saccharomyces Bni1/Spa2/Pea2/Bud6 polarisome.

A proteinaceous bacterial polar microdomain formed by PopZ polymers at Caulobacter cell poles that anchors the ParB-bound chromosomal origin and organizes pole-specific client proteins.

An Escherichia coli PotABCD ATP-binding cassette importer composed of two PotA ATP-binding subunits, one PotB permease, one PotC permease, and one PotD periplasmic substrate-binding protein that imports spermidine and can also import putrescine.

Any of the protein-DNA complexes that contain a DNA helicase and associated protein(s) at the origin of replication, and build up to assembling the core primosome. The associated protein(s) chaperone the helicase to the DNA, and assembly of the pre-primosome is essential for the initiation or restart of replication. Pre-primosome complexes lack a primase component.

A protein complex, that caps one or both ends of the proteasome core complex and regulates entry into, or exit from, the proteasome core complex.

A large multisubunit complex which catalyzes protein degradation, found in eukaryotes, archaea and some bacteria. In eukaryotes, this complex consists of the barrel shaped proteasome core complex and one or two associated proteins or complexes that act in regulating entry into or exit from the core.

A barrel-shaped self-compartmentalized protease core of proteasomes, built from stacked alpha- and beta-subunit rings that sequester threonine protease active sites in an internal chamber for protein degradation.

A protein complex which is capable of protocatechuate 3,4-dioxygenase activity. It consists of an alpha subunit (PcaG) and a beta subunit (PcaH), with the non-heme iron active site formed at the alpha-beta interface.

A protein complex that forms a subcomplex of the 90S preribosome and can interact directly with the 5' External Transcribed Spacer (ETS) of the full length pre-rRNA transcript. In S. cerevisiae, it sediments at 25-30 S and is composed of Pwp2p, Dip2p, Utp21p, Utp13p, Utp18p, and Utp6p.

A non-membrane-bounded organelle found within the chloroplasts of algae and hornworts; responsible for carbon dioxide fixation.

A nuclear assembly in which multiple chromosome ends and associated subtelomeric chromatin coalesce into fewer enlarged foci during quiescence, characterized in Saccharomyces cerevisiae and Schizosaccharomyces pombe. Nuclear position and assembly requirements depend on species, strain and starvation conditions.

A pentameric protein complex related to replication factor C that loads the checkpoint clamp onto DNA at damage sites and functions in DNA damage cell-cycle checkpoints; the large subunit is Rad17 in Schizosaccharomyces pombe and Rad24p in Saccharomyces cerevisiae.

A vacuolar membrane-anchored guanine nucleotide exchange factor (GEF) complex for the Rag GTPases (Gtr1-Gtr2 GTPase complex GO:1990131) in TORC1 signaling pathway. In human, Ragulator is comprised of the membrane anchor subunit LAMTOR1 (Meh1p in S. cerevisiae, Lam1 in S. pombe), a GEF subunit LAMTOR2 ( Slm4 in S. cerevisiae , Lam2 in S. pombe ) , LAMTOR3 (no S. cerevisiae ortholog identified, Lam3 in S. pombe) , LAMTOR4 (no S. cerevisiae ortholog identified, Lam4 in S. pombe), and LAMTOR5 (no S. cerevisiae or S. pombe ortholog identified).

A multisubunit complex that in Saccharomyces is composed of three subunits, Rav1p, Rav2p and Skp1p. Acts transiently to catalyze assembly of cytoplasmic V1 with membrane embedded V0 to form the V-ATPase holoenzyme.

The trimeric subcomplex of the retromer, believed to be closely associated with the membrane. This trimeric complex is responsible for recognizing and binding to cargo molecules. The complex comprises three Vps proteins in both yeast and mammalian cells: Vps35p, Vps29p, and Vps26p in yeast, and VPS35, VPS29 and VPS26A or VPS26B in mammals.

A conserved hetero-pentameric membrane-associated complex involved in retrograde transport from endosomes to the Golgi apparatus. The budding yeast retromer comprises Vps35p, Vps29p, Vps26p, Vps5p, and Vps17p. The mammalian complex shows slight variation in composition compared to yeast, and comprises SNX1 or SNX2, SNX5 or SNX6, VPS26A or VPS26B, VPS29, and VPS35.

The dimeric subcomplex of the retromer, believed to be peripherally associated with the membrane. This dimeric complex is responsible for remodeling endosomal membranes to form a tube-structure to which cargo molecules are selected for recycling. The budding yeast complex comprises Vps5p and Vps17p, and may contain multiple copies of a Vps5p/Vps17p dimer. The mammalian complex contains SNX1 or SNX2 dimerized with SNX5 or SNX6.

A protein complex that possesses ribonuclease H activity, in which the catalytic subunit is a member of the RNase H2 (or HII) class. For example, in Saccharomyces the complex contains Rnh201p, Rnh202p and Rnh203p.

A protein complex which is capable of ribonuclease III activity.

A histone deacetylase complex which deacetylates histones preferentially in promoter regions. Composed of a two copies of catalytic histone deacetylase subunit (S. pombe Clr6/ S. cerevisiae Rpd3p), an Sds-3 family protein (S. pombe /S. cerevisiae Sds3(p) ), two copies of SIN3 family co-repressor (S. pombe Pst1/ S. cerevisiae Sin3p, a WD repeat protein/ histone chaperone (S. pombe Prw1/ S. cerevisiae Ume1p), and a zf- PHD finger ( S. pombe Png2/ S. cerevisiae Pho23p), plus 4 additional subunits, and associated factors.

A protein complex that contains a histone deacetylase and is part of the chromatin remodeling machinery. In Saccharomyces cerevisiae this complex contains the Rpd3p, Sin3p, Ume1p, Pho23p, Sap30p, Sds3p, Cti6p, Rxt2p, Rxt3p, Dep1p, Ume6p, Ash1p, Dot6p, Snt1, Sif2p, Set3p, Hos2p, Tos4p and Tod6p proteins.

A eukaryotically conserved histone deacetylase complex which deacetylates histones across gene coding regions. Composed of a catalytic histone deacetylase subunit, a chromodomain protein, a SIN3 family co-repressor, and a WD repeat protein (Clr6p, Alp13p, Pst2p, and Prw1p respectively in Schizosaccharomyces; Rpd3p, Sin3p, Ume1p, Rco1p and Eaf3 in Saccharomyces; homologs thereof in other species).

A SWI/SNF-type complex that contains a bromodomain containing-protein, such as yeast Rsc1 or Rsc4 or mammalian PB1/BAF180. The RSC complex is generally recruited to RNA polymerase III promoters and is specifically recruited to RNA polymerase II promoters by transcriptional activators and repressors; it is also involved in non-homologous end joining.

A SAGA-type histone acetyltransferase complex that deubiquitinates H2A and/or H2B. This complex is organized into several functional submodules: a structural core including the activator binding module and consisting of ADA1 or a homolog, members of the SPT and TAF protein families as well as promotor recruitment factor TRRAP/TRA1, a histone acetyltransferase (HAT) module consisting of GCN5/KAT2A or PCAF/KAT2B, ADA2, ADA3/NGG1, and SGF29 or homologues thereof, a histone deubiquitinase (DUB) module consisting of ATXN7/SGF73, ATXN7L3/SGF11, ENY2/SUS1 and USP22/UBP8 or homologues thereof, and in some taxa a splicing module consisting of SF3B3 and SF3B5 or homologues thereof (not in fungi). In budding yeast also contains Spt8 which distinguishes it from SAGA-like (SLIK) complex (GO:0046695).

A large complex of the mitochondrial outer membrane that mediates sorting of some imported proteins to the outer membrane and their assembly in the membrane; functions after import of incoming proteins by the mitochondrial outer membrane translocase complex.

A protein complex that possesses histone acetyltransferase activity and links histone acetylation to the assembly of transcriptionally silent chromatin. In vitro, the complex acetylates lysine 16 of histone H4 and lysine 14 of histone H3, although the latter may not be relevant in vivo. The complex contains a catalytic subunit and at least two other subunits; in Saccharomyces, the catalytic subunit is Sas2p and additional subunits are Sas4p and Sas5p.

A heterotrimeric endoplasmic-reticulum membrane translocon that forms a protein-conducting channel for co- and post-translational substrate movement across or into the ER membrane.

An endoplasmic-reticulum protein complex that supports posttranslational targeting of proteins to the ER and is represented in yeast by a Sec62p, Sec63p, Sec71p, and Sec72p tetramer.

A GTPase-activating protein (GAP) complex that regulates TORC1 signaling by interacting with the Rag GTPase. In S. cerevisiae the complex contains Seh1p, Sec13p, Npr2p, Npr3p, Iml1p, Mtc5p, Rtc1p, and Sea4p.

A conserved protein complex that catalyzes methylation of histone H3. In Saccharomyces the complex contains Shg1p, Sdc1p, Swd1p, Swd2p, Swd3p, Spp1p, Bre2p, and the trithorax-related Set1p; in mammals it contains the catalytic subunit (SETD1A or SETD1B), WDR5, WDR82, RBBP5, ASH2L/ASH2, CXXC1/CFP1, HCFC1 and DPY30.

A histone deacetylase complex that is involved in transcriptional regulation. In S. cerevisiae, this complex consists of Set3p, Snt1p, Hos4p, Sif2p, Cpr1p, Hos2p, and Hst1p.

A histone deacetylase complex that contains a core of four proteins -- Clr1, Clr2, Clr3, and Mit1 in fission yeast -- and localizes to all heterochromatic regions in the genome as well as some euchromatic sites. The complex is involved in regulating nucleosome positioning to assemble higher-order chromatin structures.

A homotetrameric single-stranded DNA-binding protein assembly that binds and stabilizes single-stranded DNA during DNA replication, recombination, and repair.

A SAGA-type histone acetyltransferase complex that contains a smaller form of Spt7 (lacking the SPT8 binding region) than the fungal SAGA complex, and consequently lacks Spt8. The complex is involved in the yeast retrograde response pathway, which is important for gene expression changes during mitochondrial dysfunction.

A histone deacetylase complex that is part of the chromatin remodeling machinery. In Saccharomyces cerevisiae this complex contains Snt2p, Ecm5p and Rpd3p.

A structure within the hyphal tip of filamentous fungi that acts as an organizing center for hyphal growth.

An endoplasmic-reticulum translocon complex with a core heterotrimer of alpha, beta, and gamma subunits, represented in budding yeast by Ssh1p, Sbh2p, and Sss1p, that supports cotranslational protein transport across the ER membrane.

A protein complex containing an alkanesulfonate monooxygenase subunit (SsuD tetramer in E. coli) and a flavin oxidoreductase subunit (SsuE dimer in E. coli). Involved in the utilization of alkanesulfonates as sulfur sources under conditions of sulfate or cysteine starvation.

A bacterial cell envelope-associated multiprotein system, which binds and degrades starch.

A bacterial multiprotein regulatory assembly with an oligomeric core formed by RsbR-family and RsbS STAS domains and an associated RsbT kinase. Characterized stressosomes organize environmental-stress signaling; their subunit composition and requirement for downstream responses depend on the organism and experimental context.

A conserved DNA recombinase mediator complex that contains two Swi5 monomers and one Sfr1 monomer in Schizosaccharomyces, or orthologs thereof (e.g. Sae3p and Mei5p in Saccharomyces).

A SWI/SNF-type complex that contains 8 to 14 proteins, including both conserved (core) and nonconserved components; contains the ATPase product of the yeast SNF2 or mammalian SMARCA4/BAF190A/BRG1 gene, or an ortholog thereof.

A multisubunit INO80-type chromatin-remodeling complex that catalyzes ATP-dependent exchange of nucleosomal H2A-H2B dimers for H2AZ-H2B dimers.

A protein complex that forms a subcomplex of the 90S preribosome and is required for the subsequent assembly of the rest of the preribosome. In S. cerevisiae, it is composed of Utp5p, Utp4p, Nan1p, Utp8p, Utp9p, Utp10 and Utp15p.

A protein complex capable of catalyzing the conversion of taurine and alpha-ketoglutarate to sulfite, aminoacetaldehyde and succinate under sulfur or cysteine starvation conditions. Its expression is repressed by the presence of sulfate or cysteine. In E. coli it is a homodimer or homotetramer of the protein TauD.

A eukaryotic nuclear protein complex that promotes transcription elongation and can act as part of the transcription export complex to couple RNA polymerase II transcription with mRNA export from the nucleus.

A chloroplast inner-envelope protein translocon complex that forms the inner-membrane step of nuclear-encoded preprotein import into the chloroplast.

A multi-subunit mitochondrial inner-membrane complex that mediates insertion of multi-pass inner-membrane precursor proteins carrying internal targeting elements.

The protein transport machinery of the mitochondrial inner membrane that typically transports proteins that possess a matrix-targeting N-terminal presequence. The TIM23 complex contains three essential Tim proteins: Tim17 and Tim23 are thought to build a preprotein translocation channel while Tim44 interacts transiently with the matrix heat-shock protein Hsp70 to form an ATP-driven import motor.

A chloroplast outer-envelope protein translocon complex that forms the outer-membrane step of nuclear-encoded preprotein import into the chloroplast.

A protein complex that contains at least TOR (target of rapamycin) and Raptor (regulatory-associated protein of TOR), or orthologs of, in complex with other signaling components. Mediates the phosphorylation and activation of S6K. In Saccharomyces, the complex contains Kog1p, Lst8p, Tco89p, and either Tor1p or Tor2p.

A protein complex that contains at least TOR (target of rapamycin) and Rictor (rapamycin-insensitive companion of TOR), or orthologs of, in complex with other signaling components. Mediates the phosphorylation and activation of PKB (also called AKT). In Saccharomyces, the complex contains Avo1p, Avo2p, Tsc11p, Lst8p, Bit61p, Slm1p, Slm2p, and Tor2p.

A multiprotein complex having distributive polyadenylation activity of a variety of RNA substrates including hypomodified and incorrectly folded tRNAs, pre-snRNAs, pre-snoRNAs, incorrectly spliced or processed pre-mRNAs, cryptic unstable transcripts (CUTs), pre-rRNAs and rRNA fragments released as part of rRNA processing. In S. cerevisiae, the complex consists of either Pap2 (also known as Trf4) or Trf5, Air1 or Air2, and Mtr4, and is involved in RNA 3'-end processing and in RNA surveillance and quality control.

The 7 subunit core of TFIIH that is a part of either the general transcription factor holo-TFIIH or the nucleotide-excision repair factor 3 complex. In S. cerevisiae/humans the complex is composed of: Ssl2/XPB, Tfb1/p62, Tfb2/p52, Ssl1/p44, Tfb4/p34, Tfb5/p8 and Rad3/XPD.

A complex that is capable of kinase activity directed towards the C-terminal Domain (CTD) of the largest subunit of RNA polymerase II and is essential for initiation at RNA polymerase II promoters in vitro. It is composed of the core TFIIH complex and the TFIIK complex.

A transcription factor complex that forms part of the holo TFIIH complex. In Saccharomyces/human, TFIIK contains Ccl1p/Cyclin H, Tfb3p/MAT1 and Kin28p/CDK7.

A complex that tethers COPII vesicles at ER-Golgi intermediate compartment. Its role in this part of the vesicular transport may start at the ER exit sites. Binds to a component of the COPII coat. In yeast it includes the following subunits: Bet3 (as homodimer), Bet5, Trs20, Trs23, Trs31, Trs33 which are regarded as the core subunits of all TRAPP complexes in yeast.

A complex that mediates intra-Golgi traffic, Golgi exit, endosome-to-Golgi traffic, and the trafficking of autophagy proteins from Golgi to the phagophore assembly site. Binds to a component of the COPI coat. In yeast it includes the following subunits: Bet3 (as homodimer), Bet5, Tca17, Trs20, Trs23, Trs31, Trs33, Trs65, Trs120, Trs130. The whole complex is thought to dimerize with itself.

A complex that functions in anterograde transport at the Golgi and also regulates autophagy. In yeast it includes at least the following subunits: Bet3 (as homodimer), Bet5, Trs20, Trs23, Trs31, Trs33, Trs85. TRAPPIII may include further, as yet undescribed, proteins.

A complex consisting of two membrane proteins and one extracytoplasmic solute receptor. Such transporters transport a variety of substrates without direct ATP power, instead using energy from ion gradients.

A protein complex containing Usp7, the divergent Skp1-like protein SkpZ, and Tpr86, experimentally characterized in Trypanosoma brucei. It is distinct from cullin ubiquitin-ligase complexes and is implicated in coordinated regulation of surface-protein abundance.

A protein complex that forms a subcomplex of the 90S preribosome. In S. cerevisiae, it is composed of Rrp7p, Utp22p, Ckb1p, Cka1p, Ckb2p and Cka2p.

A membrane coat found on a coated vesicle.

A protein complex that localizes at the surface of endosomes, where it recruits and activates the Arp2/3 complex to induce actin polymerization. In human, the WASH complex is composed of F-actin-capping protein subunits alpha and beta, WASH1, FAM21, KIAA1033, KIAA0196 and CCDC53.

An error-prone eukaryotic DNA polymerase complex that carries out translesion DNA synthesis and damage-tolerance mutagenesis; in Saccharomyces cerevisiae, DNA polymerase zeta contains Rev3, Rev7, and the Pol31 and Pol32 accessory subunits shared with DNA polymerase delta.

A ribonucleoprotein complex that contains the 7SK snRNA. The 7SK snRNP plays a central role in RNA polymerase II elongation control by regulating the availability of active P-TEFb.

A large ribonucleoprotein complex considered to be the earliest preribosomal complex. In S. cerevisiae, it has a size of 90S and consists of the 35S pre-rRNA, early-associating ribosomal proteins most of which are part of the small ribosomal subunit, the U3 snoRNA and associated proteins.

The degradosome is a protein complex playing a key role in mRNA degradation and RNA processing. It includes a RNA helicase, a 3'-5' phosphate-dependent PNPase and a RNase E bound-enolase.

A class of nuclear body, first seen after silver staining by Ramon y Cajal in 1903, enriched in small nuclear ribonucleoproteins, and certain general RNA polymerase II transcription factors; ultrastructurally, they appear as a tangle of coiled, electron-dense threads roughly 0.5 micrometers in diameter; involved in aspects of snRNP biogenesis; the protein coilin serves as a marker for Cajal bodies. Some argue that Cajal bodies are the sites for preassembly of transcriptosomes, unitary particles involved in transcription and processing of RNA.

A spliceosomal complex that is formed by the displacement of the two snRNPs from the precatalytic spliceosome; three snRNPs including U5 remain associated with the mRNA. This complex, sometimes called the activated spliceosome, is the catalytically active form of the spliceosome, and includes many proteins in addition to those found in the associated snRNPs.

A spliceosomal complex that contains three snRNPs, including U5, bound to a splicing intermediate in which the first catalytic cleavage of the 5' splice site has occurred. The precise subunit composition differs significantly from that of the catalytic step 1, or activated, spliceosome, and includes many proteins in addition to those found in the associated snRNPs.

A spliceosomal complex that is formed by association of the U1 snRNP with the 5' splice site of an unspliced intron in an RNA transcript.

A ribonuclease P complex located in the cyanelle, where it catalyzes the 5' endonucleolytic cleavage of precursor tRNAs to yield mature tRNAs. The best characterized cyanelle ribonuclease P complex, from the alga Cyanophora paradoxa, contains a single RNA molecule that is necessary but not sufficient for catalysis, and several protein molecules.

A ribonuclease complex that has 3-prime to 5-prime processive hydrolytic exoribonuclease activity producing 5-prime-phosphomonoesters. Participates in a multitude of cellular RNA processing and degradation events preventing nuclear export and/or translation of aberrant RNAs. Restricted to processing linear and circular single-stranded RNAs (ssRNA) only. RNAs with complex secondary structures may have to be unwound or pre-processed by co-factors prior to entering the complex, esp if the 3-prime end is structured.

A dense aggregation in the cytosol composed of proteins and RNAs that appear when the cell is under stress.

A ribonuclease P complex that contains a single RNA molecule that is necessary and usually sufficient for catalysis, and a single protein molecule.

A ribonuclease complex with 3'-to-5' exoribonuclease activity that participates in RNA processing and degradation.

A membraneless cytoplasmic ribonucleoprotein assembly that concentrates glycolytic enzymes and associated RNAs during hypoxic growth of Saccharomyces cerevisiae.

A stress-responsive, polar, membraneless ribonucleoprotein condensate organized by Hfq in Escherichia coli, with polyphosphate-modulated assembly and enrichment of polyadenylated transcripts and RNA-processing proteins.

A nuclear body associated with the histone gene locus that is thought to contain all of the factors necessary for histone mRNA transcription and pre-mRNA processing. In Drosophila, U7 snRNP is located in the histone locus body rather than the distinct Cajal body.

A class of nuclear body measuring 20-25 nm in diameter and distributed throughout the interchromatin space, linked together by thin fibrils. They are believed to be storage centers for various snRNAs, snRNPs, serine/arginine-rich proteins and RNA polymerase II. A typical mammalian cell contains 25-50 clusters of interchromatin granules. Interchromatin granule clusters do not contain the heterogeneous nuclear RNA-binding proteins (hnRNPs).

The larger of the two subunits of a ribosome. Two sites on the ribosomal large subunit are involved in translation, namely the aminoacyl site (A site) and peptidyl site (P site).

Heteroheptameric Sm-like protein ring complex composed of Lsm2, Lsm3, Lsm4, Lsm5, Lsm6, Lsm7 and Lsm8 or their orthologs that associates with U6-family spliceosomal snRNAs.

A ribonuclease P complex that generally contains a single RNA molecule and several protein molecules. Examples of this complex are found in Archaeal species.

A small round nuclear body, measuring 0.2-0.8 microns in diameter that is diffusely distributed throughout the nucleoplasm. Several proteins known to be involved in miRNA processing have been localized to these structures. D-bodies are thought to be involved in primary-miRNA processing and/or storage/assembly of miRNA processing complexes.

A ribonuclease complex that has 3-prime to 5-prime processive and distributive hydrolytic exoribonuclease activity and endoribonuclease activity, producing 5-prime-phosphomonoesters. Participates in a multitude of cellular RNA processing and degradation events preventing nuclear export and/or translation of aberrant RNAs. Restricted to processing linear and circular single-stranded RNAs (ssRNA) only. RNAs with complex secondary structures may have to be unwound or pre-processed by co-factors prior to entering the complex, esp if the 3-prime end is structured.

A discrete extra-nucleolar subnuclear domain, 20-50 in number, in which splicing factors are seen to be localized by immunofluorescence microscopy.

A dense aggregation in the nucleus composed of proteins and RNAs that appear when the cell is under stress.

A ribonuclease complex that has 3-prime to 5-prime distributive hydrolytic exoribonuclease activity and in some taxa (e.g. yeast) endoribonuclease activity, producing 5-prime-phosphomonoesters. Participates in a multitude of cellular RNA processing and degradation events preventing nuclear export and/or translation of aberrant RNAs. Restricted to processing linear and circular single-stranded RNAs (ssRNA) only. RNAs with complex secondary structures may have to be unwound or pre-processed by co-factors prior to entering the complex, esp if the 3-prime end is structured.

A ribonuclease P complex located in the nucleolus of a eukaryotic cell, where it catalyzes the 5' endonucleolytic cleavage of precursor tRNAs to yield mature tRNAs. Eukaryotic nucleolar ribonuclease P complexes generally contain a single RNA molecule that is necessary but not sufficient for catalysis, and several protein molecules.

A nucleoplasmic speckle distributed in the interchromatin space of cells in close proximity to chromatin. Omega speckles are distinct from interchromatin granules and contain heterogeneous nuclear RNA-binding proteins (hnRNPs).

A focus in the cytoplasm where mRNAs may become inactivated by decapping or some other mechanism. Protein and RNA localized to these foci are involved in mRNA degradation, nonsense-mediated mRNA decay (NMD), translational repression, and RNA-mediated gene silencing.

Discrete subnuclear bodies in the interchromatin nucleoplasmic space, often located adjacent to nuclear specks. 10-20 paraspeckles are typically found in human cell nuclei.

A ribonucleoprotein complex that is formed by the association of the U1, U2, U4/U6 and U5 small nuclear ribonucleoproteins.

The perinucleolar compartment (PNC) is a subnuclear structure associated with, but structurally distinct from, the nucleolus. The PNC contains large amounts of the heterogeneous nuclear ribonucleoprotein complex (hnRNP) called hnRNP I (PTB). Many RNA binding proteins as well as RNA polymerase III transcripts are highly enriched in this compartment. PTB and pol III transcripts are required for the integrity of the PNC.

A spliceosomal complex that is formed following the release of the spliced product from the post-spliceosomal complex and contains the excised intron and three snRNPs, either U2 or U12, U5, and either U6 or U6atac.

A spliceosomal complex that is formed following the second splicing event and contains the spliced product, the excised intron, and three snRNPs, including U5.

A spliceosomal complex that is formed by the recruitment of a preassembled U5-containing tri-snRNP to the prespliceosome. Although all 5 snRNPs are present, the precatalytic spliceosome is catalytically inactive. The precatalytic spliceosome includes many proteins in addition to those found in the associated snRNPs.

Any complex of pre-rRNAs, ribosomal proteins, and associated proteins formed during ribosome biogenesis.

A preribosomal complex consisting of 27SA, 27SB, and/or 7S pre-rRNA, 5S rRNA, ribosomal proteins including late-associating large subunit proteins, and associated proteins; a precursor of the eukaryotic cytoplasmic large ribosomal subunit.

A preribosomal complex consisting of 20S pre-rRNA, ribosomal proteins including late-associating small subunit proteins, and associated proteins; a precursor of the eukaryotic cytoplasmic small ribosomal subunit.

A spliceosomal complex that is formed by association of the 5' splice site and the branch point sequence with specific snRNPs. The prespliceosome includes many proteins in addition to those found in the bound snRNPs. Commitment to a given pair of 5' and 3' splice sites occurs at the time of prespliceosome formation. Prespliceosome complexes are not active for splicing, but are instead an early step in the assembly of a spliceosomal complex.

A ribonucleoprotein complex that contains an RNA molecule of the snoRNA family, and cleaves the rRNA precursor as part of rRNA transcript processing. It also has other roles: In S. cerevisiae it is involved in cell cycle-regulated degradation of daughter cell-specific mRNAs, while in mammalian cells it also enters the mitochondria and processes RNAs to create RNA primers for DNA replication.

A ribonucleoprotein complex that catalyzes cleavage of the leader sequence of precursor tRNAs (pre-tRNAs), generating the mature 5' end of tRNAs.

The ribonucleoprotein particle that translates mRNA into protein. The bacterial and archaeal 70S ribosome comprises a small (30S) subunit built on 16S rRNA, which decodes the mRNA, and a large (50S) subunit built on 23S and 5S rRNA, whose 23S rRNA catalyses peptide bond formation. This record details that 70S form and the functional core shared with the larger eukaryotic cytosolic 80S ribosome; it does not enumerate 80S-specific components.

A ribonucleoprotein granule located in the cytoplasm of bacteria, minimally containing the RNase E protein and RNA molecules. Bacterial RNP-bodies are similar to eukaryotic P-bodies and stress granules.

A complex of protein and RNA which facilitates translocation of proteins across membranes.

A ribonucleoprotein complex that contains spliced leader (SL) RNA and associated proteins.

A ribonucleoprotein complex that contains at least one small nuclear RNA (snRNA) and associated proteins. Small nuclear ribonucleoproteins are typically named for the snRNA constituents they contain, such as U1 snRNP, U4/U6 snRNP, or 7SK snRNP; many become part of spliceosomes, while others regulate transcription elongation or replication-dependent histone pre-mRNA 3'-end processing.

The smaller of the two subunits of a ribosome.

A large ribonucleoprotein complex that is an early preribosomal complex. In S. cerevisiae, it has a size of 80S and consists of the 35S pre-rRNA, early-associating ribosomal proteins most of which are part of the small ribosomal subunit, the U3 snoRNA and associated proteins.

A ribonucleoprotein complex that contains an RNA molecule of the snoRNA family and associated proteins. Many are involved in a step of processing of rRNA molecules: cleavage, 2'-O-methylation, or pseudouridylation, but other RNA types can be targets as well. The majority fall into one of two classes, box C/D type or box H/ACA type, which are conserved across eukaryotes and archaea. Other members include the telomerase RNA and the ribonuclease MRP RNA.

A nuclear body that is found in the germinal vesicles of amphibian oocytes, and consist of three major parts: a remarkably spherical body about 5-10 pm in diameter, smaller spherical or nearly spherical granules on the surface, and inclusions of various sizes that strongly resemble the surface granules. The parts of the sphere organelle have distinct compositions, including splicing snRNAs and proteins.

Any of a series of ribonucleoprotein complexes that contain snRNA(s) and small nuclear ribonucleoproteins (snRNPs), and are formed sequentially during the spliceosomal splicing of one or more substrate RNAs, and which also contain the RNA substrate(s) from the initial target RNAs of splicing, the splicing intermediate RNA(s), to the final RNA products. During cis-splicing, the initial target RNA is a single, contiguous RNA transcript, whether mRNA, snoRNA, etc., and the released products are a spliced RNA and an excised intron, generally as a lariat structure. During trans-splicing, there are two initial substrate RNAs, the spliced leader RNA and a pre-mRNA.

A small ribonucleoprotein complex involved in formation of the spliceosome.

A spliceosomal snRNP complex that is formed by the association of the U4/U6 (or U4atac/U6atac) snRNP with the U5 snRNP.

Multicomponent complex of RNA and proteins that is composed of four active spliceosomes, termed native spliceosomes, connected to each other by the pre-mRNA. The supraspliceosome is the nuclear machine where the pre-mRNA processing takes place, like the 5'-end capping, 3'-end cleavage, splicing and editing.

Telomerase is a ribonucleoprotein enzyme complex, with a minimal catalytic core composed of a catalytic reverse transcriptase subunit and an RNA subunit that provides the template for telomeric DNA addition. In vivo, the holoenzyme complex often contains additional subunits.

A polar, membraneless ribonucleoprotein condensate organized by TmaR in Escherichia coli that recruits phosphotransferase-system enzyme I and participates in spatial regulation of sugar utilization.

A spliceosomal complex that forms during the addition of a specific spliced leader (SL) sequence to the 5'-end of a messenger RNA primary transcript, a process which occurs in a number of eukaryotic organisms, including trypanosomatid protozoans, euglenoids, nematodes, trematodes, and chordates.

A ribonucleoprotein complex that contains small nuclear RNA U11, a heptameric ring of Sm proteins, as well as several proteins that are unique to the U11 snRNP, most of which remain associated with the U11 snRNA both while the U11 snRNP is free or assembled into a series of spliceosomal complexes.

A ribonucleoprotein complex that is formed by the association of the U11 and U12 small nuclear ribonucleoproteins.

A ribonucleoprotein complex that contains small nuclear RNA U12, a heptameric ring of Sm proteins, as well as several proteins that are unique to the U12 snRNP, most of which remain associated with the U12 snRNA both while the U12 snRNP is free or assembled into a series of spliceosomal complexes.

A spliceosomal complex that is formed by the displacement of the U11 and U4atac snRNPs from the precatalytic spliceosome; the U12, U5 and U6atac snRNPs remain associated with the mRNA. This complex, sometimes called the activated spliceosome, is the catalytically active form of the spliceosome, and includes many proteins in addition to those found in the U12, and U5 and U6atac snRNPs.

A spliceosomal complex that contains the U12, U5 and U6atac snRNPs bound to a splicing intermediate in which the first catalytic cleavage of the 5' splice site has occurred. The precise subunit composition differs significantly from that of the catalytic step 1, or activated, spliceosome, and includes many proteins in addition to those found in the U12, U5 and U6atac snRNPs.

A spliceosomal complex that is formed following the release of the spliced product from the post-spliceosomal complex and contains the excised intron and the U12, U5 and U6atac snRNPs.

A spliceosomal complex that is formed following the second splicing event and contains the spliced product, the excised intron, and three snRNPs, U5, U12 and U6atac.

A spliceosomal complex that is formed by the recruitment of the preassembled U4atac/U6atac.U5 tri-snRNP to the U12-type prespliceosome. Although all 5 snRNPs are present, the precatalytic spliceosome is catalytically inactive. The precatalytic spliceosome includes many proteins in addition to those found in the U11, U12 and U4atac/U6atac.U5 snRNPs.

A spliceosomal complex that is formed by the cooperative binding of the heterodimeric U11/U12 snRNP to the 5' splice site and the branch point sequence. The U12-type prespliceosome includes many proteins in addition to those found in the U11/U12 heterodimeric snRNPs. Commitment to a given pair of 5' and 3' splice sites occurs at the time of prespliceosome formation.

Any spliceosomal complex that forms during the splicing of a messenger RNA primary transcript to excise an intron; the series of U12-type spliceosomal complexes is involved in the splicing of the majority of introns that contain atypical AT-AC terminal dinucleotides, as well as other non-canonical introns. The entire splice site signal, not just the terminal dinucleotides, is involved in determining which spliceosome utilizes the site.

A ribonucleoprotein complex that contains small nuclear RNA U1, a heptameric ring of Sm proteins, as well as several proteins that are unique to the U1 snRNP, most of which remain associated with the U1 snRNA both while the U1 snRNP is free or assembled into a series of spliceosomal complexes.

A ribonucleoprotein complex that contains small nuclear RNA U2, a heptameric ring of Sm proteins, as well as several proteins that are unique to the U2 snRNP, most of which remain associated with the U2 snRNA both while the U2 snRNP is free or assembled into a series of spliceosomal complexes.

A spliceosomal complex that is formed by the displacement of the U1 and U4 snRNPs from the precatalytic spliceosome; the U2, U5 and U6 snRNPs remain associated with the mRNA. This complex, sometimes called the activated spliceosome, is the catalytically active form of the spliceosome, and includes many proteins in addition to those found in the U2, and U5 and U6 snRNPs.

A spliceosomal complex that contains the U2, U5 and U6 snRNPs bound to a splicing intermediate in which the first catalytic cleavage of the 5' splice site has occurred. The precise subunit composition differs significantly from that of the catalytic step 1, or activated, spliceosome, and includes many proteins in addition to those found in the U2, U5 and U6 snRNPs.

A spliceosomal complex that is formed following the release of the spliced product from the post-spliceosomal complex and contains the excised intron and the U2, U5 and U6 snRNPs.

A spliceosomal complex that is formed following the second splicing event and contains the spliced product, the excised intron, and three snRNPs, U5, U2 and U6.

A spliceosomal complex that is formed by the recruitment of the preassembled U4/U6.U5 tri-snRNP to the prespliceosome. Although all 5 snRNPs are present, the precatalytic spliceosome is catalytically inactive. The precatalytic spliceosome includes many proteins in addition to those found in the U1, U2 and U4/U6.U5 snRNPs.

A spliceosomal complex that is formed by association of the 5' splice site with the U1 snRNP, while the branch point sequence is recognized by the U2 snRNP. The prespliceosome includes many proteins in addition to those found in the U1 and U2 snRNPs. Commitment to a given pair of 5' and 3' splice sites occurs at the time of prespliceosome formation.

Any spliceosomal complex that forms during the splicing of a messenger RNA primary transcript to excise an intron that has canonical consensus sequences near the 5' and 3' ends.

A ribonucleoprotein complex that contains small nuclear RNA U4, a heptameric ring of Sm proteins, as well as several proteins that are unique to the U4 snRNP, most of which remain associated with the U4 snRNA both while the U4 snRNP is free or assembled into the U4/U6 snRNP or into a series of spliceosomal complexes.

A ribonucleoprotein complex that contains the extensively base paired small nuclear RNAs U4 and U6, a heptameric ring of Sm proteins associated with U4, the Lsm2-8 heptameric ring complex associated with U6, as well as several proteins that are unique to the U4 snRNP or U6 snRNPs, some of which remain associated with the U4/U6 snRNA both while the U4 snRNP is free or assembled into a series of spliceosomal complexes.

A ribonucleoprotein complex that is formed by the association of the U4/U6 and U5 snRNPs.

A ribonucleoprotein complex that contains small nuclear RNA U4atac, a heptameric ring of Sm proteins, as well as several proteins that are unique to the U4atac snRNP, most of which remain associated with the U4atac snRNA both while the U4atac snRNP is free or assembled into the U4atac/U6atac complex or into a series of spliceosomal complexes.

A ribonucleoprotein complex that contains the extensively base paired small nuclear RNAs U4atac and U6atac, a heptameric ring of Sm proteins associated with U4atac, the Lsm2-8 heptameric ring complex associated with U6atac, as well as several proteins that are unique to the U4atac snRNP or U6atac snRNPs, some of which remain associated with the U4atac/U6atac snRNA both while the U4atac snRNP is free or assembled into a series of spliceosomal complexes.

A spliceosomal snRNP complex that is formed by the association of the U4atac/U6atac and U5 snRNPs.

A ribonucleoprotein complex that contains small nuclear RNA U5, a heptameric ring of Sm proteins, as well as several proteins that are unique to the U5 snRNP, most of which remain associated with the U5 snRNA both while the U5 snRNP is free or assembled into a series of spliceosomal complexes.

A ribonucleoprotein complex that contains small nuclear RNA U6, the Lsm2-8 heptameric ring complex, as well as several proteins that are unique to the U6 snRNP, most of which remain associated with the U6 snRNA both while the U6 snRNP is free or assembled into the U4/U6 snRNP or into a series of spliceosomal complexes.

A ribonucleoprotein complex that contains small nuclear RNA U6atac, the Lsm2-8 heptameric ring complex, as well as several proteins that are unique to the U6atac snRNP, most of which remain associated with the U6atac snRNA both while the U6atac snRNP is free or assembled into the U4atac/U6atac snRNP or into a series of spliceosomal complexes.

A ribonucleoprotein complex that contains the U7 snRNA and is required for the 3'-end processing of replication-dependent histone pre-mRNAs.

A protein-containing complex that serves as a channel for the secretion of curli. Curli are a fibers that serve as a major component of the extracellular matrix of pellicle biofilms.

A Mycobacterium smegmatis ESX-3 type VII secretion inner-membrane core complex in which EccB3, EccC3, EccD3, and EccE3 assemble into a dimeric membrane-embedded secretion machine.

A mycobacterial ESX-5 type VII secretion inner-membrane complex in which EccB5, EccC5, EccD5, EccE5, and MycP5 assemble into a multi-megadalton nanomachine that exports Esx and PE/PPE-family protein substrates.

An Escherichia coli Sec-pathway plasma-membrane holo-translocon complex in which SecY, SecE, SecG, SecD, SecF, YajC, and YidC assemble as a heteroheptamer that supports protein secretion and membrane-protein insertion.

A bacterial cytoplasmic-membrane Sec-pathway protein-conducting channel built from SecY, SecE, and SecG, through which unfolded secretory proteins or nascent membrane proteins move during translocation or membrane insertion.

A heterooligomeric protein complex that spans the bacterial periplasm and enables the secretion of adhesin proteins in Gram-negative bacteria. In Citrobacter rodentium, Salmonella enterica and Escherichia coli, the TAM complex consists of an Omp85-family protein, TamA, in the outer membrane and TamB in the inner membrane.

A complex of three proteins integral to the cytoplasmic membrane of bacteria and membranes of organelles derived from bacteria (chloroplasts and mitochondria) involved in membrane transport of folded proteins.

A Gram-negative bacterial trans-envelope protein secretion complex in which an inner-membrane ABC transporter and membrane-fusion protein recruit a TolC-like outer-membrane channel for one-step export of C-terminal-signal substrates.

A Gram-negative bacterial envelope-spanning secretion complex in which an inner-membrane platform and ATPase drive pseudopilus-mediated export of folded periplasmic substrates through an outer-membrane secretin.

The injectisome: a syringe-like envelope-spanning machine that delivers effector proteins from the bacterial cytoplasm directly into a eukaryotic host cell. Rings in the inner and outer membranes surround an export apparatus; an extracellular needle carries the secretion channel to a translocon pore in the host membrane. It is evolutionarily related to the flagellar export apparatus.

A bacterial envelope-spanning secretion complex related to conjugation machines that uses VirB-family channel, pilus, ATPase and coupling-protein subassemblies to translocate DNA and protein substrates.

A Bacteroidota trans-envelope secretion nanomachine that couples an inner-membrane PorL/PorM-family motor to PorK/PorN outer-membrane rings and a SprA/Sov translocon to export folded C-terminal-domain-bearing proteins across the outer membrane.

A complex of proteins that permits the translocation of proteins across the outer membrane via a transmembrane pore, formed by a beta-barrel, into the extracellular milieu or directly into host cells; the secreted proteins contain all the information required for translocation of an effector molecule through the cell envelope. The type V secretion systems includes the autotransporters (type Va), the two-partner secretion system (type Vb) and the Oca family (type Vc).

A bacterial contractile injection machine whose envelope-spanning membrane complex anchors a baseplate and sheath-wrapped Hcp tube; sheath contraction propels the Hcp/VgrG/PAAR spike and associated effectors out of the cell into target cells.