cellular bud neck split septin rings

GO:0032177 · Cytoskeleton · Filament · Proposed

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. [GO:0032177]

Part of: cellular bud neck (GO:0005935)

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
septin proteins	Protein	part of	Reviewed label only (reviewed name; no accession asserted)			ESSENTIAL	Septin GTPases that remain in the two cytokinetic rings produced from the bud-neck septin collar. `GO:0032177` GO:0032177 defines the cellular bud neck split septin rings as two septin rings formed from the bud-neck septin collar. `GO:0032161` GO:0032161 defines cleavage-apparatus septin structures as septin- and septin-associated-protein structures localized to the cleavage plane.

Functions

cytokinetic compartment boundary — The cellular bud neck split septin rings flank the budding-cell cytokinesis site and are thought to delineate a compartment in which cytokinesis factors are concentrated.
- GO:0032177 GO:0032177 defines the bud-neck split rings as two separate septin rings formed at cytokinesis and thought to delineate a cytokinesis-factor compartment.
- GO:0032176 GO:0032176 defines split septin rings as a pair of rings flanking the division site after a septin ring or collar splits before cytokinesis.

Mechanism graphs

Bud-neck split septin-rings topology (ASSEMBLY)

At budding-cell cytokinesis, the bud-neck septin collar separates into two septin rings that are thought to delineate a cytokinesis-factor compartment.

Subject	Predicate	Object	Evidence
cellular bud neck septin collar	splits into	cellular bud neck split septin rings	`GO:0032177` GO:0032177 defines the bud-neck split septin rings as two separate septin rings formed from the septin collar at cytokinesis.
cellular bud neck split septin rings	delineates	cytokinesis-factor compartment	`GO:0032177` GO:0032177 describes the two rings as thought to delineate a cytokinesis-factor compartment.
cellular bud neck split septin rings	is part of	cellular bud neck	`GO:0032177` GO:0032177 identifies the bud-neck-localized split septin rings. `GO:0005935` GO:0005935 identifies the cellular bud neck.

Discussions

INTERPRETATION (RESOLVED): Keep the cellular bud neck split septin rings distinct from the initial bud-neck septin ring and the bud-neck septin collar. GO:0000144 denotes the dynamic initial bud-neck ring that forms at bud emergence, GO:0032174 denotes the fixed hourglass-shaped collar that persists for most of the cell cycle, and GO:0032177 denotes the two split rings formed from the collar at cytokinesis. This record models only the cytokinetic split-ring state.
CURATION_TODO (OPEN): Resolve exact source-neutral family groundings and the boundary of bud-neck split-ring septins and septin-associated proteins. The first bud-neck split-ring record keeps only the reviewed-label-only septin protein cohort rather than guessing InterPro, Pfam, or NCBIfam accessions and rather than adding septin-associated proteins before their exact constituent boundary has been reviewed.

Evidence

GO:0032177 Gene Ontology cellular-component term for the cellular bud neck split septin rings.
GO:0032176 Gene Ontology cellular-component parent term for split septin rings.
GO:0032161 Gene Ontology cellular-component parent term for cleavage apparatus septin structures.
GO:0032174 Gene Ontology cellular-component term for the cellular bud neck septin collar that gives rise to the split rings.
GO:0005935 Gene Ontology cellular-component term for the cellular bud neck.

Curation history

2026-09-28T23:33:22Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-28T23:34:27Z codex · EXPANDED_RECORD — Added split-ring parentage, bud-neck parthood, a label-only septin constituent, a cytokinetic-compartment boundary function, GO evidence, a nonmechanistic collar-to-split-ring topology graph, and split-ring boundary and component-grounding discussions.
2026-09-28T23:50:31Z codex · ADDRESSED_REVIEW — Resolved #1748 by preserving the GO uncertainty qualifier on the cytokinesis-factor compartment interpretation in the split-ring function and topology graph descriptions.

Source: data/structures/cytoskeleton/cellular_bud_neck_split_septin_rings.yaml