endosome

GO:0005768 · Membrane organelle · Membrane bounded organelle · Proposed

A vacuole to which materials ingested by endocytosis are delivered. [GO:0005768]

Has part: endosome membrane (GO:0010008); endosome lumen (GO:0031904)

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
endosome membrane	Lipid	part of	`GO:0010008`			ESSENTIAL	Lipid bilayer that encloses the endosome lumen and carries sorting machinery and membrane cargo. `GO:0010008` GO:0010008 defines the endosome membrane as the lipid bilayer surrounding an endosome. `DOI:10.1083/jcb.200302136` Katzmann et al. 2003 localized yeast Vps27 and ESCRT-I recruitment to endosomal membranes during MVB sorting.

Taxonomic distribution

NCBITaxon:4932 Saccharomyces cerevisiae — COMMON: Budding yeast uses endosomes for endocytic and vacuolar protein sorting, including ESCRT-dependent multivesicular-body traffic. [PMID:11511343]

Canonical examples

NCBITaxon:4932 Saccharomyces cerevisiae — Genetic model in which Vps27 and ESCRT-I, ESCRT-II and ESCRT-III were tied to endosomal multivesicular-body cargo sorting. [DOI:10.1083/jcb.200302136]

Functions

endosomal transport GO:0016197 — Endosomes move internalized and biosynthetic membrane cargo through the yeast endomembrane system toward the vacuole.
- GO:0016197 GO:0016197 defines endosomal transport as directed movement of lumenal or membrane substances mediated by an endosome.
- DOI:10.1016/j.devcel.2011.05.015 Henne, Buchkovich and Emr 2011 reviewed the ESCRT pathway as a conserved route for endosomal cargo sorting.
multivesicular body sorting — Endosomal sorting machinery recognizes ubiquitinated membrane cargo and packages it into intraluminal vesicles of multivesicular bodies.
- PMID:11511343 Katzmann, Babst and Emr 2001 identified ESCRT-I as a conserved endosomal protein-sorting complex needed for yeast MVB sorting.
- DOI:10.1016/j.devcel.2004.09.003 Teo et al. 2004 described ESCRT-II as part of the sequentially recruited endosomal ESCRT machinery and mapped direct ESCRT-II binding to the Vps20 subunit of ESCRT-III.

Mechanism graphs

ESCRT machinery sorts endosomal cargo into multivesicular bodies (FUNCTION)

In Saccharomyces cerevisiae, Vps27 and ESCRT complexes are recruited to endosomal membranes to sort ubiquitinated membrane cargo and package it into multivesicular-body intraluminal vesicles.

Subject	Predicate	Object	Evidence
endosome membrane	bounds	endosome lumen	`GO:0031904` GO:0031904 defines the endosome lumen as the volume enclosed by the membrane of an endosome.
Vps27 endosomal ESCRT-I recruiter	recruits	ESCRT I complex	`DOI:10.1083/jcb.200302136` Katzmann et al. 2003 found that yeast Vps27 recruits ESCRT-I to endosomal membranes.
ESCRT I complex	sorts	ubiquitinated membrane cargo	`PMID:11511343` Katzmann, Babst and Emr 2001 showed ESCRT-I is needed for ubiquitin-dependent MVB cargo sorting.
ESCRT II complex	recruits	ESCRT III complex	`DOI:10.1016/j.devcel.2004.09.003` Teo et al. 2004 described ESCRT-II as part of the sequentially recruited endosomal ESCRT machinery and mapped direct ESCRT-II binding to the Vps20 subunit of ESCRT-III.
ESCRT III complex	remodels	endosome membrane	`PMID:12194857` Babst et al. 2002 characterized yeast ESCRT-III as an endosome-associated hetero-oligomeric protein complex required for MVB sorting.
endosome membrane	forms	multivesicular body intraluminal vesicle	`GO:0005771` GO:0005771 defines multivesicular bodies as endosomes with internal vesicles formed by invagination of the limiting endosomal membrane.
multivesicular body intraluminal vesicle	is contained in	multivesicular body	`GO:0005771` GO:0005771 defines multivesicular bodies as endosomes with internal vesicles formed by limiting-membrane invagination.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral groundings and separate record boundaries for Vps27 cargo-recognition machinery, ESCRT-I, ESCRT-II, ESCRT-III, Doa4 and Vps4 before adding a more detailed MVB-sorting machinery model. This first endosome record grounds the membrane boundary and uses GO-grounded ESCRT complexes as graph nodes, but keeps transient cargo-recognition, deubiquitination and recycling machinery out of the endosome component table until exact complex boundaries or dedicated subcomplex records are reviewed.

Evidence

GO:0005768 Gene Ontology cellular-component term for endosome.
GO:0010008 Gene Ontology cellular-component term for the endosome membrane.
GO:0031904 Gene Ontology cellular-component term for the endosome lumen.
GO:0005771 Gene Ontology cellular-component term for the multivesicular body.
GO:0016197 Gene Ontology biological-process term for endosomal transport.
DOI:10.1016/j.devcel.2011.05.015 Henne, Buchkovich and Emr 2011, The ESCRT Pathway, Developmental Cell.
PMID:11511343 Katzmann, Babst and Emr 2001, Ubiquitin-Dependent Sorting into the Multivesicular Body Pathway Requires the Function of a Conserved Endosomal Protein Sorting Complex, ESCRT-I, Cell.
DOI:10.1083/jcb.200302136 Katzmann, Stefan, Babst and Emr 2003, Vps27 recruits ESCRT machinery to endosomes during MVB sorting, Journal of Cell Biology.
DOI:10.1016/j.devcel.2004.09.003 Teo et al. 2004 described ESCRT-II as part of the sequentially recruited endosomal ESCRT machinery and mapped direct ESCRT-II binding to the Vps20 subunit of ESCRT-III.
PMID:12194857 Babst et al. 2002, ESCRT-III, Developmental Cell.

Curation history

2026-09-12T00:30:41Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-12T00:31:18Z codex · EXPANDED_RECORD — Added endosome membrane and lumen parthood, an endosome membrane component, Saccharomyces distribution and example curation, endosomal transport and multivesicular-body sorting functions, GO/DOI evidence, a yeast ESCRT MVB sorting graph and an ESCRT machinery boundary TODO.
2026-09-12T00:37:55Z codex · RESOLVED_REVIEW — Resolved #554 by narrowing the Vps27 graph node, resolved #556 by retargeting endosomal invagination to an intraluminal-vesicle node, and resolved #555 by keeping transient ESCRT sorting machinery out of future endosome component wording.
2026-09-21T08:16:18Z codex · REPLACED_UNREADABLE_EVIDENCE — Resolved #1222 by replacing unreadable Babst et al. 2002 ESCRT-II evidence with reachable Teo et al. 2004 support for the ESCRT-II to ESCRT-III handoff in the yeast MVB sorting pathway.
2026-09-21T08:41:49Z codex · REPLACED_UNREADABLE_EVIDENCE — Resolved #1224 by routing Katzmann, Babst and Emr 2001 ESCRT-I evidence through reachable PMID:11511343 instead of the unreadable Cell DOI.
2026-09-21T09:03:20Z codex · REPLACED_UNREADABLE_EVIDENCE — Resolved #1225 by routing Babst et al. 2002 ESCRT-III evidence through reachable PMID:12194857 instead of the unreadable Developmental Cell DOI.
2026-09-23T08:14:15Z codex · LINKED_INTRALUMINAL_VESICLE_RECORD — Grounded the multivesicular-body intraluminal vesicle graph node to cellstructuremech:multivesicular_body_intraluminal_vesicle.

Source: data/structures/membrane_organelle/endosome.yaml