COPI vesicle coat

GO:0030126 · Other · Multiprotein complex · Proposed

A COPI membrane vesicle coat complex found associated with Golgi membranes; it forms on COPI-coated vesicles that mediate Golgi-to-endoplasmic-reticulum retrograde transport. [GO:0030126]

Synonyms: coatomer

Part of: COPI-coated vesicle (GO:0030137)

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
coatomer complex	Protein complex	part of	Reviewed label only (reviewed name; no accession asserted)			UNKNOWN	Core coatomer complex that assembles with Arf on Golgi membranes to form the COPI coat. `DOI:10.1038/349248a0` Waters, Serafini and Rothman 1991 named coatomer as a cytosolic protein complex containing non-clathrin Golgi vesicle coat subunits. `DOI:10.1091/mbc.e02-11-0736` Sandmann et al. 2003 described COPI retrograde vesicles and direct binding of a KKXX ER-retrieval motif by coatomer in Saccharomyces cerevisiae.
Arf-family COPI GTPase	Protein	part of	Reviewed label only (reviewed name; no accession asserted)			UNKNOWN	Small GTPase coat constituent that associates with Golgi-derived COP-coated vesicles and promotes coat assembly on membranes. `DOI:10.1016/j.cell.2012.01.015` Yu et al. 2012 showed that Arf1-GTP binds two coatomer subcomplexes during COPI coatomer recruitment to membranes.

Taxonomic distribution

NCBITaxon:4932 Saccharomyces cerevisiae — COMMON: Budding yeast has a COPI coatomer system that retrieves dilysine-tagged early secretory cargo to the endoplasmic reticulum. [DOI:10.1091/mbc.e02-11-0736]

Canonical examples

NCBITaxon:4932 Saccharomyces cerevisiae — Budding-yeast model in which coatomer mutants established COPI roles in Golgi-to-ER retrieval and early secretory trafficking. [DOI:10.1091/mbc.e02-11-0736]

Functions

COPI-coated vesicle budding GO:0035964 — The COPI vesicle coat forms during evagination of Golgi membranes into COPI-coated vesicles.
- GO:0035964 GO:0035964 denotes evagination of a Golgi membrane to form a COPI-coated vesicle.
- DOI:10.1016/j.cell.2012.01.015 Yu et al. 2012 analyzed Arf1-GTP binding to coatomer subcomplexes during COPI coat recruitment to membranes.
retrograde vesicle-mediated transport, Golgi to endoplasmic reticulum GO:0006890 — In budding yeast, coatomer-dependent COPI traffic returns dilysine-tagged cargo from the Golgi to the endoplasmic reticulum.
- GO:0006890 GO:0006890 denotes retrograde vesicle-mediated transport from the Golgi apparatus to the endoplasmic reticulum.
- DOI:10.1091/mbc.e02-11-0736 Sandmann et al. 2003 described COPI retrograde vesicles and direct binding of a KKXX ER-retrieval motif by coatomer in Saccharomyces cerevisiae.

Mechanism graphs

Arf and coatomer assemble COPI coats at Golgi membranes (ASSEMBLY)

Arf-family GTPases and the coatomer complex assemble on Golgi membranes into the COPI vesicle coat that forms COPI-coated vesicles for retrograde Golgi-to-ER traffic.

Subject	Predicate	Object	Evidence
Arf-family COPI GTPase	associates with	Golgi membrane	`DOI:10.1016/j.cell.2012.01.015` Yu et al. 2012 showed that Arf1-GTP binds coatomer and drives its recruitment to membranes.
coatomer complex	assembles with	Arf-family COPI GTPase	`DOI:10.1016/j.cell.2012.01.015` Yu et al. 2012 showed that two Arf1-GTP molecules interact with distinct coatomer subcomplexes.
coatomer complex	is part of	COPI vesicle coat	`DOI:10.1038/349248a0` Waters, Serafini and Rothman 1991 defined coatomer as a non-clathrin Golgi vesicle coat protein complex.
Arf-family COPI GTPase	is part of	COPI vesicle coat	`DOI:10.1016/j.cell.2012.01.015` Yu et al. 2012 showed that Arf1-GTP interacts with COPI coatomer during membrane recruitment.
COPI vesicle coat	assembles on	Golgi membrane	`GO:0035964` GO:0035964 defines COPI-coated vesicle budding as evagination of a Golgi membrane.
COPI vesicle coat	is part of	COPI-coated vesicle	`GO:0030137` GO:0030137 defines a COPI-coated vesicle by its COPI coat complex proteins.
COPI vesicle coat	participates in	COPI-coated vesicle budding	`GO:0035964` GO:0035964 defines COPI-coated vesicle budding as evagination of a Golgi membrane that yields a COPI-coated vesicle.
COPI vesicle coat	participates in	retrograde vesicle-mediated transport, Golgi to endoplasmic reticulum	`GO:0006890` GO:0006890 covers retrograde vesicle-mediated transport from the Golgi to the endoplasmic reticulum. `DOI:10.1091/mbc.e02-11-0736` Sandmann et al. 2003 described COPI retrograde vesicles and direct binding of a KKXX ER-retrieval motif by coatomer.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral groundings for individual coatomer subunit families and the Arf paralogues that join COPI coats. This first COPI record models the coatomer and Arf layers at coarse granularity. Individual coatomer subunit families and the Saccharomyces Arf paralogues need exact family boundaries before adding subunit-level components or protein examples.

Evidence

GO:0030126 Gene Ontology cellular-component term for the COPI vesicle coat.
GO:0030120 Gene Ontology cellular-component parent for vesicle coats.
GO:0030137 Gene Ontology cellular-component term for COPI-coated vesicles.
GO:0035964 Gene Ontology biological-process term for COPI-coated vesicle budding.
GO:0006890 Gene Ontology biological-process term for retrograde vesicle-mediated transport from the Golgi to the endoplasmic reticulum.
DOI:10.1038/349248a0 Waters, Serafini and Rothman 1991, 'Coatomer': a cytosolic protein complex containing subunits of non-clathrin-coated Golgi transport vesicles, Nature.
DOI:10.1016/j.cell.2012.01.015 Yu et al. 2012, A Structure-Based Mechanism for Arf1-Dependent Recruitment of Coatomer to Membranes, Cell.
DOI:10.1091/mbc.e02-11-0736 Sandmann et al. 2003, Suppression of Coatomer Mutants by a New Protein Family with COPI and COPII Binding Motifs in Saccharomyces cerevisiae, Molecular Biology of the Cell.

Curation history

2026-09-12T07:39:57Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-12T07:40:30Z codex · EXPANDED_RECORD — Added vesicle-coat parentage, COPI-coated vesicle parthood, exact coatomer synonymy, reviewed-label-only coatomer and Arf components, Saccharomyces scope, COPI budding and Golgi-to-ER retrieval functions, DOI/GO evidence, a nonmechanistic coat-assembly graph, and a subunit-grounding TODO.
2026-09-12T07:40:51Z codex · CURATED_PARENT_EVIDENCE — Added GO:0030120 record-level evidence for vesicle-coat parentage.
2026-09-12T07:48:20Z codex · ADDRESSED_PR_REVIEW — Resolved PR #608 review issues #609, #610, and #611 by grounding Golgi-to-ER retrograde transport to GO:0006890, adding that process to the graph, descoping the coatomer component label, and removing misplaced Sandmann cargo-motif evidence from the Arf component.
2026-09-21T11:01:21Z codex · REPLACED_UNREADABLE_EVIDENCE — Resolved #1235 by replacing unreadable Serafini and Letourneur COPI citations with reachable Yu et al. 2012 Arf1-coatomer and Sandmann et al. 2003 Golgi-to-ER retrieval evidence.

Source: data/structures/other/copi_vesicle_coat.yaml