cellular bud neck septin ring

GO:0000144 · Cytoskeleton · Filament · Proposed

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. [GO:0000144]

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 assemble into the dynamic ring at the Saccharomyces future bud site. `GO:0000144` GO:0000144 defines the cellular bud neck septin ring as composed of septins and septin-associated proteins. `DOI:10.1091/mbc.E04-09-0764` Kozubowski et al. 2005 describe Saccharomyces septins forming a ring-shaped scaffold at the future budding site.

Taxonomic distribution

NCBITaxon:4932 Saccharomyces cerevisiae — COMMON: Budding-yeast septins form an initial ring at the future budding site that later rearranges into the hourglass-shaped bud-neck collar. [DOI:10.1091/mbc.E04-09-0764]

Canonical examples

NCBITaxon:4932 Saccharomyces cerevisiae — Budding-yeast model in which the initial future-bud-site septin ring gives way to a mother-bud-neck septin collar. [DOI:10.1091/mbc.E04-09-0764]

Functions

future-bud-site scaffold — The cellular bud neck septin ring is the dynamic initial septin scaffold that marks the future bud site before rearranging into the mother-bud-neck collar.
- GO:0000144 GO:0000144 defines the structure as a Saccharomyces septin ring that forms at bud emergence and shows rapid septin exchange.
- DOI:10.1091/mbc.E04-09-0764 Kozubowski et al. 2005 describe the septin scaffold as ring-shaped at the future budding site before it rearranges into the mother-bud-neck collar.

Mechanism graphs

Bud-neck septin ring topology (ASSEMBLY)

Septin proteins assemble into the exchangeable initial ring that rearranges into the hourglass-shaped collar at the Saccharomyces mother-bud neck.

Subject	Predicate	Object	Evidence
septin proteins	assemble into	cellular bud neck septin ring	`GO:0000144` GO:0000144 defines the cellular bud neck septin ring as a ring-shaped septin-containing structure.
cellular bud neck septin ring	rearranges into	cellular bud neck septin collar	`DOI:10.1091/mbc.E04-09-0764` Kozubowski et al. 2005 describe the Saccharomyces septin ring at the future budding site as rearranging into a collar at the mother-bud neck.
cellular bud neck septin ring	is part of	cellular bud neck	`GO:0000144` GO:0000144 places the septin ring in the bud neck of a budding cell. `GO:0005935` GO:0005935 identifies the cellular bud neck.

Discussions

INTERPRETATION (RESOLVED): Keep the cellular bud neck septin ring distinct from the bud-neck septin collar and split septin rings. 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 initial ring state.
CURATION_TODO (OPEN): Resolve exact source-neutral family groundings and boundary status for bud-neck septin-ring septins and septin-associated proteins. The first localized bud-neck septin-ring record keeps only the reviewed-label-only septin protein cohort rather than guessing InterPro, Pfam, or NCBIfam accessions and rather than adding the GO-defined septin-associated proteins before their exact constituent boundary has been reviewed.

Evidence

GO:0000144 Gene Ontology cellular-component term for the cellular bud neck septin ring.
GO:0005940 Gene Ontology cellular-component parent term for septin ring.
GO:0005935 Gene Ontology cellular-component term for the cellular bud neck.
DOI:10.1091/mbc.E04-09-0764 Kozubowski, Larson and Tatchell 2005, 'Role of the Septin Ring in the Asymmetric Localization of Proteins at the Mother-Bud Neck in Saccharomyces cerevisiae', Molecular Biology of the Cell.
DOI:10.1016/j.tcb.2005.06.007 Versele and Thorner 2005, 'Some assembly required: yeast septins provide the instruction manual', Trends in Cell Biology.

Curation history

2026-09-28T22:52:03Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-28T22:53:18Z codex · EXPANDED_RECORD — Added septin-ring parentage, bud-neck parthood, a reviewed-label-only septin constituent, Saccharomyces distribution and canonical example evidence, a future-bud-site scaffold function, a nonmechanistic ring-to-collar topology graph, and ring-boundary and component-grounding discussions.
2026-09-28T23:07:47Z codex · ADDRESSED_REVIEW — Resolved #1746 by attaching the bud-neck septin-ring component TODO at record scope as well as to the reviewed-label-only septin component.

Source: data/structures/cytoskeleton/cellular_bud_neck_septin_ring.yaml