plastid inner membrane

GO:0009528 · Membrane organelle · Membrane · Proposed

The inner, i.e. lumen-facing, lipid bilayer of the plastid envelope; also faces the plastid stroma. [GO:0009528]

Synonyms: Inner plastidic membrane; Inner plastid membrane; Plastidic inner membrane

Part of: plastid envelope (GO:0009526)

Xrefs: uniprot.location:SL-0211 — Plastid inner membrane

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
plastid inner lipid bilayer	Lipid	part of	Reviewed label only (reviewed name; no accession asserted)			ESSENTIAL	Stroma-facing lipid bilayer that separates the plastid stroma from the intermembrane space. `GO:0009528` GO:0009528 defines plastid inner membrane as the inner lipid bilayer of the plastid envelope that also faces the plastid stroma. `uniprot.location:SL-0211` — Plastid inner membrane UniProt SL-0211 identifies plastid inner membrane as separating the plastid stroma from the intermembrane space.

NCBITaxon:33090 Viridiplantae — COMMON: Green algae and land plants carry primary plastids bounded by double envelopes with stroma-facing inner plastid membranes. [DOI:10.1098/rstb.2009.0103]
NCBITaxon:3055 Chlamydomonas reinhardtii — COMMON: The Chlamydomonas reinhardtii chloroplast inner membrane forms the stroma-facing side of the chloroplast envelope and carries the Tic side of the TOC-TIC protein-import supercomplex. [DOI:10.1016/j.cell.2022.10.030]

NCBITaxon:3055 Chlamydomonas reinhardtii — Green-algal model used for structural analysis of a TOC-TIC supercomplex spanning the chloroplast outer and inner envelope membranes. [DOI:10.1016/j.cell.2022.10.030]

The plastid inner membrane is the stroma-facing lipid bilayer of the plastid envelope and delimits the plastid intermembrane space.

Subject	Predicate	Object	Evidence
plastid inner membrane	is part of	plastid envelope	`GO:0009528` GO:0009528 defines this inner membrane as a lipid bilayer of the plastid envelope.
plastid inner membrane	bounds	plastid stroma	`GO:0009528` GO:0009528 identifies the inner plastid membrane as the bilayer that also faces the plastid stroma. `GO:0009532` GO:0009532 identifies the plastid stroma as the ground substance of plastids. `uniprot.location:SL-0211` — Plastid inner membrane UniProt SL-0211 describes the plastid inner membrane as separating the plastid stroma from the intermembrane space.
plastid inner membrane	delimits	plastid intermembrane space	`GO:0009529` GO:0009529 defines the plastid intermembrane space as the region between the inner and outer plastid envelope lipid bilayers. `uniprot.location:SL-0211` — Plastid inner membrane UniProt SL-0211 describes the plastid inner membrane as separating the plastid stroma from the intermembrane space.

CURATION_TODO (OPEN): Resolve an exact source-neutral grounding for the lipid constituent of the plastid inner membrane. The record is exactly grounded to GO:0009528 and UniProt SL-0211, but the lipid bilayer constituent is intentionally left as a reviewed-label-only component until an exact source-neutral lipid or membrane-constituent CURIE is curated.

GO:0009528 Gene Ontology cellular-component term for plastid inner membrane.
GO:0042170 Gene Ontology cellular-component term for generic plastid membranes.
GO:0009526 Gene Ontology cellular-component term for plastid envelope.
GO:0009529 Gene Ontology cellular-component term for plastid intermembrane space.
GO:0009532 Gene Ontology cellular-component term for plastid stroma.
uniprot.location:SL-0211 — Plastid inner membrane UniProt Subcellular Location entry SL-0211 maps Plastid inner membrane to GO:0009528.
DOI:10.1098/rstb.2009.0103 Keeling 2010, The endosymbiotic origin, diversification and fate of plastids, Philosophical Transactions of the Royal Society B.
DOI:10.1016/j.cell.2022.10.030 Jin et al. 2022, Structure of a TOC-TIC supercomplex spanning two chloroplast envelope membranes, Cell.

2026-09-13T21:25:42Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-13T21:26:07Z codex · EXPANDED_RECORD — Added plastid-membrane parentage, plastid-envelope parthood, the UniProt SL-0211 xref and exact synonyms, a reviewed-label-only inner lipid bilayer component, Viridiplantae/Chlamydomonas scope, GO/UniProt/DOI evidence, a nonmechanistic topology graph, and a lipid-bilayer grounding TODO.