nuclear outer membrane

GO:0005640 · Membrane organelle · Membrane · Proposed

The outer, i.e. cytoplasm-facing, lipid bilayer of the nuclear envelope. [GO:0005640]

Synonyms: outer nuclear membrane

Part of: nuclear envelope (GO:0005635)

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
nuclear outer membrane lipid bilayer	Lipid	part of	Reviewed label only (reviewed name; no accession asserted)			ESSENTIAL	Cytoplasm-facing lipid-bilayer constituent of the nuclear envelope outer membrane. `GO:0005640` GO:0005640 defines the nuclear outer membrane as the cytoplasm-facing lipid bilayer of the nuclear envelope.

NCBITaxon:4932 Saccharomyces cerevisiae — COMMON: Budding-yeast outer nuclear membrane protein Nvj1p forms nucleus-vacuole junctions by directly interacting with the vacuolar protein Vac8p. [DOI:10.1091/mbc.11.7.2445]

NCBITaxon:4932 Saccharomyces cerevisiae — Budding-yeast model in which outer-nuclear-membrane Nvj1p and vacuolar Vac8p were shown to form nucleus-vacuole junctions. [DOI:10.1091/mbc.11.7.2445]

nucleus-vacuole junction formation — The yeast nuclear outer membrane anchors Nvj1p, which interacts with Vac8p on the vacuole to form nucleus-vacuole junctions.
- DOI:10.1091/mbc.11.7.2445 Pan et al. 2000 showed that Saccharomyces cerevisiae Nvj1p and Vac8p directly interact to form nucleus-vacuole junctions.

The nuclear outer membrane is the cytoplasm-facing nuclear envelope membrane and carries Nvj1p for yeast nucleus-vacuole junction formation.

Subject	Predicate	Object	Evidence
nuclear outer membrane	is part of	nuclear envelope	`GO:0005640` GO:0005640 defines the nuclear outer membrane as the cytoplasm-facing lipid bilayer of the nuclear envelope.
nuclear envelope lumen	lies between	nuclear outer membrane	`GO:0005641` GO:0005641 defines the nuclear envelope lumen as the region between the two nuclear envelope bilayers. `GO:0005637` GO:0005637 identifies the inner nuclear envelope bilayer. `GO:0005640` GO:0005640 identifies the outer nuclear envelope bilayer.
nuclear envelope lumen	lies between	nuclear inner membrane	`GO:0005641` GO:0005641 defines the nuclear envelope lumen as the region between the two nuclear envelope bilayers. `GO:0005637` GO:0005637 identifies the inner nuclear envelope bilayer.
Nvj1p	localizes to	nuclear outer membrane	`DOI:10.1091/mbc.11.7.2445` Pan et al. 2000 identified Nvj1p as an outer nuclear membrane protein at nucleus-vacuole junctions.
Vac8p	localizes to	vacuolar membrane	`DOI:10.1091/mbc.11.7.2445` Pan et al. 2000 identified Vac8p as the vacuolar Nvj1p partner that forms nucleus-vacuole junctions.
Nvj1p	interacts with	Vac8p	`DOI:10.1091/mbc.11.7.2445` Pan et al. 2000 found that Nvj1p directly interacts with Vac8p to form nucleus-vacuole junctions.

INTERPRETATION (RESOLVED): Keep the paired nuclear inner membrane and nuclear envelope lumen as neighboring nuclear-envelope structures rather than as nuclear outer membrane components. GO:0005640 denotes the outer bilayer of the nuclear envelope, GO:0005637 denotes the distinct inner bilayer, and GO:0005641 denotes the lumen between those bilayers.
CURATION_TODO (OPEN): Resolve exact source-neutral groundings for yeast Nvj1p and Vac8p. This record uses Nvj1p and Vac8p in the functional graph to capture the cited yeast nucleus-vacuole junction example but leaves those protein nodes ungrounded until exact UniProtKB or family-level identifiers can be verified.

GO:0005640 Gene Ontology cellular-component term for nuclear outer membrane.
GO:0031090 Gene Ontology cellular-component parent term for organelle membrane.
GO:0005635 Gene Ontology cellular-component term for the containing nuclear envelope.
GO:0005637 Gene Ontology cellular-component term for the paired nuclear inner membrane.
GO:0005641 Gene Ontology cellular-component term for the nuclear envelope lumen between the inner and outer nuclear membranes.
GO:0005774 Gene Ontology cellular-component term for the vacuolar membrane contacted by yeast Nvj1p at nucleus-vacuole junctions.
DOI:10.1091/mbc.11.7.2445 Pan et al. 2000, 'Nucleus-Vacuole Junctions in Saccharomyces cerevisiae Are Formed Through the Direct Interaction of Vac8p with Nvj1p', Molecular Biology of the Cell.

2026-09-15T05:49:35Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-15T05:50:16Z codex · EXPANDED_RECORD — Added exact outer nuclear membrane synonymy, organelle-membrane parentage, nuclear-envelope parthood, a reviewed-label-only lipid-bilayer component, Saccharomyces Nvj1p/Vac8p evidence, a nonmechanistic outer-membrane contact graph, and boundary and protein-grounding discussions.
2026-09-15T06:02:32Z codex · REVIEW_FIX — Addressed review issues #938 and #939 by connecting the nuclear envelope lumen to the nuclear inner membrane and Vac8p to the vacuolar membrane in the contact graph.