ventral disc supernumerary microtubule array

GO:0097596 · Cytoskeleton · Filament · Proposed

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. [DOI:10.1371/journal.pone.0043783]

Part of: ventral disc (GO:0097597)

Has part: microtubule (GO:0005874)

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
alpha- and beta-tubulins	Protein	part of	Reviewed label only (reviewed name; no accession asserted)			UNKNOWN	Tubulin constituents that polymerize into the supernumerary microtubules of the Giardia ventral disc. `GO:0097596` Gene Ontology defines the ventral disc supernumerary microtubule array as an array of microtubules. `GO:0005874` Gene Ontology defines microtubules as tubes of polymeric tubulin. `DOI:10.1371/journal.pone.0043783` Schwartz et al. 2012 used electron tomography to map the Giardia ventral-disc microtubule arrays.

Taxonomic distribution

NCBITaxon:5741 Giardia intestinalis — COMMON: Giardia intestinalis is the diplomonad species in which the supernumerary microtubules associated with the ventral disc were mapped by electron tomography. [DOI:10.1371/journal.pone.0043783]

Canonical examples

NCBITaxon:5741 Giardia intestinalis — Parasitic diplomonad model used for electron-tomographic mapping of ventral-disc supernumerary microtubules. [DOI:10.1371/journal.pone.0043783]

Mechanism graphs

Supernumerary-array topology in the Schwartz 2012 reconstruction (FUNCTION)

In the Giardia reconstruction reported by Schwartz et al. 2012, the supernumerary microtubules form a short right-handed spiral fragment ventral to the main ventral-disc array.

Subject	Predicate	Object	Evidence
ventral disc supernumerary microtubule array	lies ventral to	ventral disc microtubule array	`DOI:10.1371/journal.pone.0043783` Figure 1F and its caption place the yellow supernumerary array ventral to the white main array; Results describe a short right-handed spiral fragment.
ventral disc supernumerary microtubule array	is part of	ventral disc	`GO:0097596` Gene Ontology models GO:0097596 as part of GO:0097597, the ventral disc.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral grounding for the alpha- and beta-tubulins and accessory proteins that build the Giardia ventral-disc supernumerary microtubule array. This first ventral-disc supernumerary-microtubule record keeps only a broad alpha- and beta-tubulin component because no exact source-neutral CURIE was verified for the tubulins or accessory microtubule-associated proteins specific to the supernumerary array.
INTERPRETATION (RESOLVED): Preserve conflicting source descriptions of supernumerary-array position and handedness. GO:0097596 describes a partial left-handed array generally dorsal to the main array. The cited Schwartz et al. 2012 reconstruction instead shows a ventral array in Figure 1F and describes a short right-handed fragment in Results. Hagen et al. 2011 describe a left-handed partial array with slightly dorsal or ventral localization in Figure 5.

Evidence

GO:0097596 Gene Ontology cellular-component term for the Giardia ventral-disc supernumerary microtubule array.
DOI:10.1371/journal.pone.0043783 Schwartz et al. 2012 reconstructed Giardia ventral-disc architecture. Figure 1F places the supernumerary array ventral to the main array, and Results describe a short right-handed fragment.
DOI:10.1371/journal.pntd.0001442 Hagen et al. 2011 describe a partial left-handed supernumerary array; Figure 5 reports tagged supernumerary proteins slightly dorsal or ventral to the main array. These descriptions are retained as a conflict with Schwartz et al. 2012, not combined into a universal geometry.

Curation history

2026-09-15T16:31:51Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-15T16:32:47Z codex · EXPANDED_RECORD — Added ventral-disc partonomy, a label-only tubulin component, Giardia intestinalis scope, DOI evidence, a nonmechanistic supernumerary-array topology graph, and a supernumerary microtubule component-grounding TODO.
2026-09-15T16:41:15Z codex · REVIEW_FIX — Addressed PR #999 review issue #1001 by removing the structural topology function and generic tubulin assembly edge, then retargeting the graph to the GO-backed supernumerary-array topology relation.
2026-10-11T17:03:39Z codex · ADDRESS_SAVED_REVIEW — Addressed #2229: Bound the supernumerary-array orientation to Schwartz 2012 and preserved the GO/Hagen source conflict explicitly; did not restore unsupported assembly or function.

Source: data/structures/cytoskeleton/ventral_disc_supernumerary_microtubule_array.yaml