spore inner membrane

GO:0140549 · Spore · Membrane · Proposed

The membrane surrounding the spore core (endospore core) that separates it from its external environment. [GO:0140549]

Synonyms: spore membrane

Taxonomic distribution

NCBITaxon:1239 Bacillota — COMMON: Spore inner membranes surround the dormant core in endospore-forming Bacillota lineages, while many non-sporulating Bacillota lack the endospore pathway. [DOI:10.1038/nrmicro2921]

NCBITaxon:1423 Bacillus subtilis — Classical bacterial endospore model in which the mature core is surrounded by the spore inner membrane and external cortex and coat layers. [DOI:10.1038/nrmicro2921]

The spore inner membrane surrounds the endospore core and separates that dormant interior from the mature-spore exterior.

Subject	Predicate	Object	Evidence
spore inner membrane	surrounds	endospore core	`GO:0140549` GO:0140549 defines the spore inner membrane by its position around the endospore core.
spore inner membrane	separates endospore core from	mature-spore exterior	`GO:0140549` GO:0140549 defines the spore inner membrane as the membrane that separates the endospore core from its external environment.

INTERPRETATION (RESOLVED): Keep the spore inner membrane separate from the generic UniProt Spore membrane location, the forespore membrane, the outer endospore membrane, and non-bacterial prospore membranes. GO:0140549 denotes the bacterial membrane surrounding the endospore core, GO:0043594 denotes the separate outer endospore membrane between cortex and coat, GO:0005628 denotes a fungal ascospore-type prospore membrane, and UniProt SL-0363 is a broader spore membrane location without a GO mapping.

GO:0140549 Gene Ontology cellular-component term for the spore inner membrane.
GO:0016020 Gene Ontology cellular-component term for membrane parentage.
GO:0070477 Gene Ontology cellular-component term for the endospore core surrounded by the spore inner membrane.
GO:0043595 Gene Ontology cellular-component term for the surrounding endospore cortex.
uniprot.location:SL-0363 — Spore membrane UniProt Subcellular Location SL-0363 identifies a generic Spore membrane location, records spore inner membrane as an alternate name, and does not map the location to GO.
DOI:10.1038/nrmicro2921 McKenney, Driks and Eichenberger 2012, The Bacillus subtilis endospore: assembly and functions of the multilayered coat, Nature Reviews Microbiology.

2026-09-22T23:52:12Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-22T23:52:56Z codex · EXPANDED_RECORD — Added the broad GO synonym, membrane parentage, Bacillota distribution, a Bacillus subtilis example, GO/UniProt/literature evidence, a nonmechanistic mature-spore topology graph, and an inner-membrane boundary discussion.
2026-09-23T00:05:28Z codex · ADDRESS_REVIEW — Resolved #1336 by correcting the UniProt SL-0363 scope note to leave broad-synonym provenance on GO:0140549, and resolved #1337 by narrowing the causal graph to inner-membrane topology.