cyanelle outer membrane

GO:0036013 · Membrane organelle · Membrane · Proposed

The outer, i.e. cytoplasm-facing, lipid bilayer of the cyanelle envelope. [GO:0036013]

Part of: cyanelle envelope (GO:0033112)

Xrefs: uniprot.location:SL-0482 — Cyanelle outer membrane

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
cyanelle outer lipid bilayer	Lipid	part of	Reviewed label only (reviewed name; no accession asserted)			ESSENTIAL	Cytoplasm-facing lipid bilayer that forms the outer boundary of the cyanelle envelope. `GO:0036013` GO:0036013 defines the cyanelle outer membrane as the cytoplasm-facing lipid bilayer of the cyanelle envelope. `uniprot.location:SL-0482` — Cyanelle outer membrane UniProt SL-0482 maps directly to GO:0036013 and describes the same cytoplasm-facing cyanelle membrane. `DOI:10.1074/jbc.M116.746131` Kojima et al. 2016 localized Cyanophora paradoxa outer-cyanelle-membrane proteins outside the peptidoglycan layer.

NCBITaxon:38254 Glaucocystophyceae — COMMON: The cyanelle outer membrane is the cytoplasm-facing envelope boundary of glaucophyte cyanelles. [uniprot.location:SL-0482 — Cyanelle outer membrane]
NCBITaxon:2762 Cyanophora paradoxa — COMMON: Cyanophora paradoxa cyanelles have cytoplasm-facing outer membranes outside the cyanelle peptidoglycan layer. [DOI:10.1074/jbc.M116.746131]

NCBITaxon:2762 Cyanophora paradoxa — Model glaucophyte used for biochemical localization of outer cyanelle membrane proteins. [DOI:10.1074/jbc.M116.746131]

The cyanelle outer membrane is the cytoplasm-facing lipid bilayer that also bounds the intermembrane space of the cyanelle envelope.

Subject	Predicate	Object	Evidence
cyanelle outer membrane	is part of	cyanelle envelope	`GO:0036013` GO:0036013 defines this outer membrane as a lipid bilayer of the cyanelle envelope. `uniprot.location:SL-0482` — Cyanelle outer membrane UniProt SL-0482 places the cyanelle outer membrane under the cyanelle envelope.
cyanelle outer membrane	faces	cytoplasm	`GO:0036013` GO:0036013 defines this membrane by its cytoplasm-facing position in the envelope. `uniprot.location:SL-0482` — Cyanelle outer membrane UniProt SL-0482 describes the cyanelle outer membrane as facing the cytoplasm.
cyanelle outer membrane	bounds	cyanelle intermembrane space	`GO:0036014` GO:0036014 defines the cyanelle intermembrane space as the region between the inner and outer lipid bilayers of the envelope. `DOI:10.1074/jbc.M116.746131` Kojima et al. 2016 localized Cyanophora paradoxa outer-cyanelle-membrane proteins outside the peptidoglycan layer, consistent with the peptidoglycan-bearing intermembrane space inside the outer membrane.

CURATION_TODO (OPEN): Resolve an exact source-neutral grounding for the lipid constituent of the cyanelle outer membrane. The record is exactly grounded to GO:0036013 and UniProt SL-0482, 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:0036013 Gene Ontology cellular-component term for cyanelle outer membrane.
GO:0009527 Gene Ontology cellular-component term for plastid outer membrane.
GO:0033113 Gene Ontology cellular-component term for the generic cyanelle membrane parent.
GO:0033112 Gene Ontology cellular-component term for cyanelle envelope.
GO:0036014 Gene Ontology cellular-component term for the cyanelle intermembrane space.
uniprot.location:SL-0482 — Cyanelle outer membrane UniProt Subcellular Location entry SL-0482 maps Cyanelle outer membrane to GO:0036013 and places it under cyanelle membrane and plastid outer membrane.
DOI:10.1104/pp.71.2.409 Giddings, Wasmann and Staehelin 1983, Structure of the Thylakoids and Envelope Membranes of the Cyanelles of Cyanophora paradoxa, Plant Physiology.
DOI:10.1074/jbc.M116.746131 Kojima, Muramoto and Kusano 2016, Outer Membrane Proteins Derived from Non-cyanobacterial Lineage Cover the Peptidoglycan of Cyanophora paradoxa Cyanelles and Serve as a Cyanelle Diffusion Channel, Journal of Biological Chemistry.

2026-09-12T20:43:39Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-12T20:44:23Z codex · EXPANDED_RECORD — Added plastid-outer and cyanelle-membrane parentage, cyanelle-envelope parthood, the UniProt SL-0482 xref, a reviewed-label-only outer lipid bilayer component, glaucophyte distribution, a Cyanophora paradoxa canonical example, a nonmechanistic topology graph, and a lipid-bilayer grounding TODO.
2026-09-12T20:53:27Z codex · RESOLVED_REVIEW — Addressed #704 by adding GO:0036014 cyanelle intermembrane-space evidence and a bounded intermembrane-space node to the outer-membrane topology graph.
2026-09-21T10:04:10Z codex · REPLACED_UNREADABLE_EVIDENCE — Replaced unreadable Jackson et al. 2015 Glaucophyta evidence with reachable cyanelle evidence for #1231.