Appendage

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.