ciliary basal body

GO:0036064 · Cytoskeleton · Other · Proposed

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. [GO:0036064]

Synonyms: cilial basal body; cilium basal body; kinetosome; microtubule basal body; basal body

Part of: cilium (GO:0005929)

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
basal-body triplet microtubules	Other	part of	Reviewed label only (reviewed name; no accession asserted)			UNKNOWN	Nine triplet microtubule blades build the cylindrical basal-body wall in Chlamydomonas. `DOI:10.1186/s13630-016-0039-z` Dutcher and O'Toole 2016 review the Chlamydomonas basal body as a cylinder made from nine triplet microtubules. `DOI:10.3390/cells7070079` Wingfield and Lechtreck 2018 describe wild-type Chlamydomonas basal bodies as nine triplet microtubules around a central cartwheel. `DOI:10.1091/mbc.9.6.1293` Dutcher and Trabuco 1998 observed proximal doublets rather than triplets in uni3-1 basal bodies, with zero-, one- and two-flagellum cells in the mutant population. Their Discussion leaves a requirement for triplets in flagellar nucleation open. These observations distinguish normal triplet architecture from malformed basal-body formation but do not establish complete loss of all triplet material in every functional ciliary basal body. Assembly essentiality remains UNKNOWN, not a claim of universal dispensability.
basal-body cartwheel	Other	part of	Reviewed label only (reviewed name; no accession asserted)			UNKNOWN	Proximal ninefold-symmetric scaffold that organizes basal-body assembly and helps template the arrangement of triplet microtubules. `DOI:10.1083/jcb.200402022` Matsuura et al. 2004 localized Chlamydomonas Bld10p to the cartwheel and connected the cartwheel to the first ninefold-symmetric stage of basal-body assembly. `DOI:10.1186/s13630-016-0039-z` Dutcher and O'Toole 2016 review the cartwheel among the conserved Chlamydomonas basal-body substructures. `DOI:10.1016/j.cub.2007.11.046` The inspected Nakazawa et al. 2007 primary abstract reports that SAS-6-null bld12 lacks the central cartwheel part yet retains centrioles with variable triplet counts. Loss of the central part is not demonstrated removal of every cartwheel or spoke-tip component. These results support a role in normal organization without establishing an absolute whole-substructure formation requirement; assembly essentiality remains UNKNOWN. Full experimental text of the 2007 source was not inspected.

Taxonomic distribution

NCBITaxon:3055 Chlamydomonas reinhardtii — COMMON: Vegetative Chlamydomonas cells have two ciliary basal bodies that nucleate the paired motile flagella. [DOI:10.3390/cells7070079]

Canonical examples

NCBITaxon:3055 Chlamydomonas reinhardtii — Green-algal reference organism whose basal bodies have been used to study triplet-microtubule architecture, cartwheel assembly and flagellar nucleation. [DOI:10.1186/s13630-016-0039-z]

Functions

cilium assembly GO:0060271 — The basal body anchors the cilium and acts as the base from which axonemal microtubules are assembled.
- GO:0036064 GO defines the ciliary basal body as the ciliary assembly and remodeling site that nucleates axoneme growth.
- DOI:10.1104/pp.010807 Silflow and Lefebvre 2001 review basal bodies as centriolar organizers of Chlamydomonas flagella.

Physical properties

SUBUNIT_COUNT: 9 (triplet microtubule blades per wild-type Chlamydomonas basal body) [DOI:10.1186/s13630-016-0039-z]

Mechanism graphs

The cartwheel organizes the triplet microtubule cylinder (ASSEMBLY)

A proximal cartwheel organizes ninefold basal-body symmetry, nine triplet microtubule blades form the basal-body cylinder, and the assembled basal body anchors the cilium and nucleates axonemal microtubules. This is a nonmechanistic summary. This graph summarizes major Chlamydomonas basal-body substructures and leaves cartwheel protein stoichiometry, centriole maturation, transition fibers and rootlet attachments for later component-level curation. The graph describes normal wild-type architecture, not an absolute substructure-essentiality claim or the morphology of every mutant basal body.

Subject	Predicate	Object	Evidence
basal-body cartwheel	organizes	basal-body triplet microtubules	`DOI:10.1083/jcb.200402022` Matsuura et al. 2004 localized Bld10p to the cartwheel and proposed that it acts early in Chlamydomonas basal-body assembly.
basal-body triplet microtubules	form wall of	ciliary basal body	`DOI:10.1186/s13630-016-0039-z` Dutcher and O'Toole 2016 review the nine triplet microtubules of Chlamydomonas basal bodies.
ciliary basal body	nucleates	axoneme	`GO:0036064` GO defines the ciliary basal body as a ciliary base structure that nucleates axoneme growth.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral identifiers for the ciliary basal-body cartwheel and triplet-microtubule substructures before expanding them to individual SAS-6, Bld10/CEP135, tubulin and delta/epsilon-tubulin protein-family components. The structural cartwheel and triplet-microtubule components are conserved basal-body parts, but a first record should not guess generic InterPro, Pfam or GO terms for substructures that need exact family and boundary review.

Evidence

GO:0036064 Gene Ontology cellular-component term for the ciliary basal body.
GO:0005929 Gene Ontology cellular-component term for the cilium; the term places GO:0036064 as part of the cilium.
DOI:10.1186/s13630-016-0039-z Dutcher and O'Toole 2016, The basal bodies of Chlamydomonas reinhardtii, Cilia.
DOI:10.3390/cells7070079 Wingfield and Lechtreck 2018, Chlamydomonas Basal Bodies as Flagella Organizing Centers, Cells.
DOI:10.1083/jcb.200402022 Matsuura et al. 2004, Bld10p, a novel protein essential for basal body assembly in Chlamydomonas: localization to the cartwheel, the first ninefold symmetrical structure appearing during assembly, Journal of Cell Biology.
DOI:10.1104/pp.010807 Silflow and Lefebvre 2001, Assembly and motility of eukaryotic cilia and flagella. Lessons from Chlamydomonas reinhardtii, Plant Physiology.
GO:0005815 Gene Ontology places GO:0036064 ciliary basal body as is_a microtubule organizing center. This is a class relationship, not equivalence to the whole cytoskeleton.

Curation history

2026-09-13T09:11:04Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-13T09:12:50Z codex · EXPANDED_RECORD — Added GO synonymy, cilium parthood, label-only triplet-microtubule and cartwheel components, Chlamydomonas scope, cilium-assembly function, a triplet-count property, DOI evidence, a nonmechanistic basal-body assembly graph, and a substructure-grounding TODO.
2026-09-13T09:24:44Z codex · ADDRESS_REVIEW — #767: removed the GO-only Eukaryota VARIABLE distribution row because it was a clade-level assertion that needs direct literature support; kept the directly supported Chlamydomonas reinhardtii row.
2026-10-12T01:19:47Z codex · ADDRESS_SAVED_REVIEW — Addressed #2275, #2276: corrected the organizing-center is-a parent, set triplet/cartwheel assembly essentiality to UNKNOWN with bounded primary evidence, and made normal wild-type architecture scope explicit.
2026-10-12T01:28:50Z codex · ADDRESS_SAVED_REVIEW — Addressed #2277: exposed the existing graph scope and nonmechanistic classification in the displayed description; original scope fields and graph relations retained.

Source: data/structures/cytoskeleton/ciliary_basal_body.yaml