exocyst

GO:0000145 · Other · Multiprotein complex · Proposed

A vesicle tethering complex peripherally associated with the plasma membrane that determines where vesicles dock and fuse. At least eight complex components are conserved between yeast and mammals. [GO:0000145]

Synonyms: exocyst complex; Sec6/8 complex

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Components

Component	Type	Part of / acts on	Grounding	Genes	Essential	Role
Sec3 exocyst subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	SEC3	UNKNOWN	Exocyst subunit that marks polarized exocytic sites at the yeast plasma membrane. `DOI:10.1016/S0092-8674(00)80948-4` Finger et al. 1998 characterized Sec3p as a spatial landmark for polarized secretion in budding yeast. `DOI:10.1002/j.1460-2075.1996.tb01039.x` TerBush et al. 1996 named the Sec3p/Sec5p/Sec6p/Sec8p/Sec10p/Sec15p/Exo70p complex the exocyst and showed that it is required for exocytosis in Saccharomyces cerevisiae.
Sec5 exocyst subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	SEC5	UNKNOWN	Constituent of the yeast exocyst identified when the Sec6/Sec8/Sec15 complex was expanded. `DOI:10.1002/j.1460-2075.1996.tb01039.x` TerBush et al. 1996 named the Sec3p/Sec5p/Sec6p/Sec8p/Sec10p/Sec15p/Exo70p complex the exocyst and showed that it is required for exocytosis in Saccharomyces cerevisiae.
Sec6 exocyst subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	SEC6	UNKNOWN	Constituent of the yeast exocyst and of the original Sec6/Sec8/Sec15 complex. `DOI:10.1083/jcb.130.2.299` TerBush and Novick 1995 identified Sec6p, Sec8p, and Sec15p in a multisubunit complex at small bud tips. `DOI:10.1002/j.1460-2075.1996.tb01039.x` TerBush et al. 1996 named the Sec3p/Sec5p/Sec6p/Sec8p/Sec10p/Sec15p/Exo70p complex the exocyst and showed that it is required for exocytosis in Saccharomyces cerevisiae.
Sec8 exocyst subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	SEC8	UNKNOWN	Constituent of the yeast exocyst and of the original Sec6/Sec8/Sec15 complex. `DOI:10.1083/jcb.130.2.299` TerBush and Novick 1995 identified Sec6p, Sec8p, and Sec15p in a multisubunit complex at small bud tips. `DOI:10.1002/j.1460-2075.1996.tb01039.x` TerBush et al. 1996 named the Sec3p/Sec5p/Sec6p/Sec8p/Sec10p/Sec15p/Exo70p complex the exocyst and showed that it is required for exocytosis in Saccharomyces cerevisiae.
Sec10 exocyst subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	SEC10	UNKNOWN	Constituent of the yeast exocyst identified when the Sec6/Sec8/Sec15 complex was expanded. `DOI:10.1002/j.1460-2075.1996.tb01039.x` TerBush et al. 1996 named the Sec3p/Sec5p/Sec6p/Sec8p/Sec10p/Sec15p/Exo70p complex the exocyst and showed that it is required for exocytosis in Saccharomyces cerevisiae.
Sec15 exocyst subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	SEC15	UNKNOWN	Exocyst subunit that connects the complex to Sec4p-positive secretory vesicles. `DOI:10.1083/jcb.130.2.299` TerBush and Novick 1995 identified Sec6p, Sec8p, and Sec15p in a multisubunit complex at small bud tips. `DOI:10.1093/emboj/18.4.1071` Guo et al. 1999 connected Sec15p with GTP-bound Sec4p during secretory-vesicle targeting.
Exo70 exocyst subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	EXO70	UNKNOWN	Constituent of the yeast exocyst identified when the Sec6/Sec8/Sec15 complex was expanded. `DOI:10.1002/j.1460-2075.1996.tb01039.x` TerBush et al. 1996 named the Sec3p/Sec5p/Sec6p/Sec8p/Sec10p/Sec15p/Exo70p complex the exocyst and showed that it is required for exocytosis in Saccharomyces cerevisiae.
Exo84 exocyst subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	EXO84	UNKNOWN	Exocyst protein required for secretion in Saccharomyces cerevisiae. `DOI:10.1074/jbc.274.33.23558` Guo et al. 1999 identified Exo84p as an exocyst protein essential for secretion.

Canonical examples

NCBITaxon:4932 Saccharomyces cerevisiae — Budding-yeast model in which the Sec6/Sec8/Sec15 complex was expanded to the named exocyst required for exocytosis. [DOI:10.1002/j.1460-2075.1996.tb01039.x]

Functions

exocytosis GO:0006887 — The exocyst targets secretory vesicles to plasma-membrane exocytic sites.
- GO:0006887 Gene Ontology biological-process term for exocytosis.
- DOI:10.1093/emboj/18.4.1071 Guo et al. 1999 studied the exocyst as a Sec4p effector for secretory-vesicle targeting.

Mechanism graphs

Sec4 and Sec15 link secretory vesicles to exocytic sites (FUNCTION)

In budding yeast, Sec4p interacts with the exocyst component Sec15p on secretory vesicles, Sec3p marks polarized plasma-membrane sites, and the exocyst targets vesicles to those sites.

Subject	Predicate	Object	Evidence
Sec4p	interacts with	Sec15 exocyst subunit	`DOI:10.1093/emboj/18.4.1071` Guo et al. 1999 tested GTP-bound Sec4p interaction with Sec15p during vesicle targeting.
Sec15 exocyst subunit	is constituent of	exocyst	`DOI:10.1083/jcb.130.2.299` TerBush and Novick 1995 identified Sec15p in the Sec6/Sec8/Sec15 complex. `DOI:10.1002/j.1460-2075.1996.tb01039.x` TerBush et al. 1996 named the Sec3p/Sec5p/Sec6p/Sec8p/Sec10p/Sec15p/Exo70p complex the exocyst and showed that it is required for exocytosis in Saccharomyces cerevisiae.
Sec3 exocyst subunit	marks	polarized exocytic sites	`DOI:10.1016/S0092-8674(00)80948-4` Finger et al. 1998 characterized Sec3p as a spatial landmark for polarized secretion.
exocyst	targets	secretory vesicles	`DOI:10.1093/emboj/18.4.1071` Guo et al. 1999 framed the exocyst as a Sec4p effector system for targeted secretion.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral family groundings for the eight S. cerevisiae exocyst subunits. This first exocyst record names experimentally defined Saccharomyces subunits but leaves InterPro/Pfam grounding unset until exact orthology and paralogy boundaries are reviewed per subunit.
CURATION_TODO (RESOLVED): Should Sec4p be curated as an exocyst component? Sec4p acts through the exocyst component Sec15p during targeting of secretory vesicles; it is not part of the stable exocyst complex defined by the Sec and Exo subunits.

Evidence

GO:0000145 Gene Ontology cellular-component term for exocyst.
GO:0006887 Gene Ontology biological-process term for exocytosis.
DOI:10.1083/jcb.130.2.299 TerBush and Novick 1995, 'Sec6, Sec8, and Sec15 are components of a multisubunit complex which localizes to small bud tips in Saccharomyces cerevisiae', Journal of Cell Biology.
DOI:10.1002/j.1460-2075.1996.tb01039.x TerBush et al. 1996, 'The Exocyst is a multiprotein complex required for exocytosis in Saccharomyces cerevisiae', The EMBO Journal.
DOI:10.1016/S0092-8674(00)80948-4 Finger et al. 1998, 'Sec3p is a spatial landmark for polarized secretion in budding yeast', Cell.
DOI:10.1093/emboj/18.4.1071 Guo et al. 1999, 'The exocyst is an effector for Sec4p, targeting secretory vesicles to sites of exocytosis', The EMBO Journal.
DOI:10.1074/jbc.274.33.23558 Guo et al. 1999, 'Exo84p is an exocyst protein essential for secretion', Journal of Biological Chemistry.

Curation history

2026-09-12T01:09:42Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-12T01:11:38Z codex · EXPANDED_RECORD — Added GO synonymy, eight reviewed label-only yeast exocyst subunits, variable eukaryotic scope, a Saccharomyces cerevisiae canonical example, exocytosis function, DOI/GO evidence, a nonmechanistic Sec4/Sec15/Sec3 targeting graph, a subunit-grounding TODO, and a resolved Sec4p boundary decision.
2026-09-12T01:19:56Z codex · ADDRESS_REVIEW — Addressed PR #561 review issues #562 and #563 by removing the unsupported Eukaryota taxonomic-distribution row and adding a secretory-vesicle node to the Sec4/Sec15 graph.

Source: data/structures/other/exocyst.yaml