medial cortex septin ring

GO:0036391 · Cytoskeleton · Filament · Proposed

A ring-shaped structure that forms at the medial cortex of a symmetrically dividing cell at the onset of cytokinesis; composed of members of the conserved family of filament forming proteins called septins as well as septin-associated proteins. [GO:0036391]

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 ring-shaped structure at the medial cortex during the onset of cytokinesis. `GO:0036391` GO:0036391 defines the medial cortex septin ring as composed of septins and septin-associated proteins. `GO:0005940` GO:0005940 defines the broader septin ring as a septin- and septin-associated-protein structure.

Mechanism graphs

Medial-cortex septin-ring topology (ASSEMBLY)

Septin proteins form a ring-shaped structure at the medial cortex of a symmetrically dividing cell at the onset of cytokinesis.

Subject	Predicate	Object	Evidence
septin proteins	assemble into	medial cortex septin ring	`GO:0036391` GO:0036391 defines the medial cortex septin ring as composed of septins and septin-associated proteins.
medial cortex septin ring	forms at	medial cortex	`GO:0036391` GO:0036391 places the medial cortex septin ring at the medial cortex of a symmetrically dividing cell.

Discussions

INTERPRETATION (RESOLVED): Keep the medial cortex septin ring distinct from other localized septin-ring states. GO:0036391 denotes the ring that forms at the medial cortex of a symmetrically dividing cell at the onset of cytokinesis. GO:0000144 and GO:0032177 cover bud-neck septin states in budding cells, GO:0032169 covers the prospore ring, GO:0032175 covers the mating projection ring, GO:0032168 and GO:0032172 cover filamentous-fungal hyphal and germ-tube rings, GO:0032170 covers pseudohyphal-projection junctions, and GO:0005940 denotes the broader septin ring class. This record models only the medial-cortex subtype.
CURATION_TODO (OPEN): Resolve exact source-neutral family groundings and boundary status for medial-cortex septin-ring septins and septin-associated proteins. The first medial-cortex septin-ring record keeps only the reviewed-label-only septin protein cohort rather than guessing paralog family groundings or adding septin-associated proteins before their exact constituent boundary has been reviewed.

Evidence

GO:0036391 Gene Ontology cellular-component term for the medial cortex septin ring.
GO:0005940 Gene Ontology cellular-component parent term for the septin ring.

Curation history

2026-09-29T03:22:09Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-29T03:22:52Z codex · EXPANDED_RECORD — Added septin-ring parentage, a reviewed-label-only septin constituent, GO evidence, a nonmechanistic medial-cortex topology graph, and boundary and component-grounding discussions.
2026-09-29T03:37:41Z codex · ADDRESSED_REVIEW — Resolved #1759 by distinguishing the GO:0036391 medial cortex septin ring from the GO:0032175 mating projection septin ring.

Source: data/structures/cytoskeleton/medial_cortex_septin_ring.yaml