prospore membrane leading edge

GO:0070056 · Spore · Subcellular region · Proposed

The region of the prospore membrane that extends to surround the spore nucleus; coated with specific proteins that are thought to play a role in prospore membrane organization. [GO:0070056]

Synonyms: forespore membrane leading edge

Part of: prospore membrane (GO:0005628)

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
prospore membrane leading edge protein coat	Protein complex	part of	Reviewed label only (reviewed name; no accession asserted)	SSP1, ADY3, DON1		UNKNOWN	Protein coat at the lip of the growing prospore membrane that marks the leading edge before membrane closure. `GO:0070056` GO:0070056 defines the prospore membrane leading edge as a protein-coated region of the prospore membrane. `DOI:10.1093/emboj/20.24.6946` Moreno-Borchart et al. 2001 linked formation of the Saccharomyces prospore membrane to leading-edge protein coat assembly.

Taxonomic distribution

NCBITaxon:4932 Saccharomyces cerevisiae — COMMON: Budding yeast builds a prospore membrane leading edge at the protein-coated rim of each extending prospore membrane during sporulation. [DOI:10.1093/emboj/20.24.6946]

Canonical examples

NCBITaxon:4932 Saccharomyces cerevisiae — Budding-yeast model in which Ssp1, Ady3 and Don1 were used to define the leading-edge protein coat on growing prospore membranes. [DOI:10.1093/emboj/20.24.6946]

Functions

prospore membrane rim organization — In budding yeast, leading-edge proteins assemble at the open lip of the growing prospore membrane and mark the membrane rim before closure.
- GO:0070056 GO:0070056 identifies the protein-coated leading edge region of the extending prospore membrane.
- DOI:10.1093/emboj/20.24.6946 Moreno-Borchart et al. 2001 connected leading-edge protein coat assembly to Saccharomyces prospore membrane formation.

Mechanism graphs

Leading-edge coat proteins mark the open prospore membrane rim (ASSEMBLY)

The leading-edge protein coat localizes to the protein-coated region at the open lip of the extending prospore membrane in budding yeast.

Subject	Predicate	Object	Evidence
prospore membrane leading edge protein coat	localizes to	prospore membrane leading edge	`DOI:10.1093/emboj/20.24.6946` Moreno-Borchart et al. 2001 tied LEP coat assembly to formation of the growing prospore membrane. `GO:0070056` GO:0070056 describes a protein-coated leading-edge region on the prospore membrane.
prospore membrane leading edge	is part of	prospore membrane	`GO:0070056` GO:0070056 identifies the prospore membrane leading edge. `GO:0005628` GO:0005628 identifies the parent prospore membrane.
prospore membrane leading edge	extends around	haploid meiotic nucleus	`GO:0070056` GO:0070056 defines the leading edge as the region of the prospore membrane that extends to surround the spore nucleus.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral groundings and component boundaries for the prospore membrane leading-edge coat subunits. This first leading-edge record treats the coat as one reviewed-label-only constituent and records Saccharomyces SSP1, ADY3 and DON1 as gene-symbol metadata. Exact family groundings for individual Ssp1, Ady3, Don1 and Irc10 components, and the boundary between stable coat proteins and Spo20/Sso1 fusion machinery, need a focused curation pass.

Evidence

GO:0070056 Gene Ontology cellular-component term for the prospore membrane leading edge.
GO:0005628 Gene Ontology cellular-component term for the prospore membrane that contains the leading edge.
GO:0016020 Gene Ontology cellular-component parent term for membrane.
DOI:10.1093/emboj/20.24.6946 Moreno-Borchart et al. 2001, Prospore membrane formation linked to the leading edge protein (LEP) coat assembly, The EMBO Journal.

Curation history

2026-09-15T08:20:56Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-15T08:21:35Z codex · EXPANDED_RECORD — Added membrane parentage, prospore-membrane parthood, a reviewed-label-only leading-edge-coat component, Saccharomyces scope, rim-organization function, GO/DOI evidence, a nonmechanistic topology graph, and a leading-edge-coat grounding TODO.
2026-09-15T08:22:08Z codex · FIXED_CURATION_METADATA — Marked the scaffold curation event as LLM-assisted.
2026-09-15T08:35:43Z codex · ADDRESSED_REVIEW — Resolved review issues #952 and #953 by adding the GO exact synonym and representing the spore-nucleus spatial relation in the graph.
2026-09-20T21:51:50Z codex · ADDRESSED_REVIEW — Retyped the leading-edge protein coat graph node as STRUCTURE.

Source: data/structures/spore/prospore_membrane_leading_edge.yaml