prospore contractile ring

GO:0032157 · Cytoskeleton · Filament · Proposed

A contractile ring composed of actin filaments and myosin that forms beneath the plasma membrane of the prospore envelope in meiotic cells in preparation for completing cytokinesis. [GO:0032157]

Synonyms: actomyosin ring; cytokinetic ring; meiotic contractile ring

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
actin filaments	Protein	part of	Reviewed label only (reviewed name; no accession asserted)			UNKNOWN	Filamentous actin constituent of the actomyosin ring that forms beneath the prospore-envelope plasma membrane. `GO:0032157` GO:0032157 defines the prospore contractile ring as a cytoskeletal structure composed of actin filaments and myosin. This ontology definition supports composition and location, not a component-removal test of ring assembly. Assembly essentiality remains UNKNOWN pending organism- and component-scoped experimental evidence; membership alone does not establish a universal requirement.
myosin proteins	Protein	part of	Reviewed label only (reviewed name; no accession asserted)			UNKNOWN	Myosin constituent of the actin-containing cytokinetic ring that forms during prospore cytokinesis. `GO:0032157` GO:0032157 defines the prospore contractile ring as a cytoskeletal structure composed of actin filaments and myosin. This ontology definition supports composition and location, not a component-removal test of ring assembly. Assembly essentiality remains UNKNOWN pending organism- and component-scoped experimental evidence; membership alone does not establish a universal requirement.

Mechanism graphs

Prospore contractile-ring topology (ASSEMBLY)

Actin filaments and myosin form the contractile ring beneath the plasma membrane of the prospore envelope during meiotic cytokinesis.

Subject	Predicate	Object	Evidence
actin filaments	contributes to	prospore contractile ring	`GO:0032157` GO:0032157 defines the prospore contractile ring as composed of actin filaments and myosin.
myosin proteins	contributes to	prospore contractile ring	`GO:0032157` GO:0032157 defines the prospore contractile ring as composed of actin filaments and myosin.
prospore contractile ring	forms beneath	prospore-envelope plasma membrane	`GO:0032157` GO:0032157 localizes the ring beneath the plasma membrane of the prospore envelope.

Discussions

INTERPRETATION (RESOLVED): Keep the prospore contractile ring distinct from generic actomyosin contractile rings and from prospore septin rings. GO:0032157 denotes an actin- and myosin-containing contractile ring that forms beneath the prospore-envelope plasma membrane during meiotic cytokinesis. GO:0005826 denotes the broader actomyosin contractile ring class, GO:0110086 denotes the broader meiotic actomyosin contractile ring class, and GO:0032169 denotes a separate prospore septin ring assembled from septins and septin-associated proteins.
CURATION_TODO (OPEN): Resolve exact source-neutral family groundings and species-specific boundaries for the actin and myosin constituents of the prospore contractile ring. The first GO-backed prospore contractile ring record keeps only the broad actin and myosin constituents from the GO definition rather than guessing exact InterPro, Pfam, or NCBIfam accessions or choosing between Saccharomyces and Schizosaccharomyces meiotic actomyosin-ring component sets without a primary-literature pass.

Evidence

GO:0032157 Gene Ontology cellular-component term for the prospore contractile ring.
GO:0110086 Gene Ontology cellular-component parent term for meiotic actomyosin contractile rings.
GO:0005826 Gene Ontology cellular-component ancestor term for actomyosin contractile rings.

Curation history

2026-09-29T06:18:50Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-29T06:21:00Z codex · EXPANDED_RECORD — Added GO synonymy, actomyosin-ring parentage, reviewed-label-only actin and myosin constituents, GO evidence, a nonmechanistic topology graph, and boundary and component-grounding discussions.
2026-09-29T06:34:38Z codex · ADDRESSED_REVIEW — Resolved PR #1766 review issue #1767 by replacing the generic GO:0005826 parent with the nearer GO:0110086 meiotic actomyosin contractile ring parent.
2026-10-12T02:39:13Z codex · ADDRESS_SAVED_REVIEW — Addressed #2280: Keep ontology-defined prospore-ring membership separate from unverified assembly essentiality.

Source: data/structures/cytoskeleton/prospore_contractile_ring.yaml