AP-5 adaptor complex

GO:0044599 · Other · Multiprotein complex · Proposed

An AP-type membrane coat adaptor complex that in humans consists of beta5, zeta, mu5 and sigma5 subunits and is found associated with membranes in the endosomes; it is not clear whether AP-5 forms clathrin coats in vivo. [GO:0044599]

Synonyms: adaptor protein-5 adaptor complex

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

Components

Component	Type	Part of / acts on	Grounding	Essential	Role
AP-5 beta5 subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	UNKNOWN	Large beta5 subunit of the heterotetrameric AP-5 adaptor complex. `GO:0044599` GO:0044599 defines human AP-5 as consisting of beta5, zeta, mu5 and sigma5 subunits.
AP-5 zeta subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	UNKNOWN	Large zeta subunit of the heterotetrameric AP-5 adaptor complex. `GO:0044599` GO:0044599 defines human AP-5 as consisting of beta5, zeta, mu5 and sigma5 subunits.
AP-5 mu5 subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	UNKNOWN	Medium mu5 subunit of the heterotetrameric AP-5 adaptor complex. `GO:0044599` GO:0044599 defines human AP-5 as consisting of beta5, zeta, mu5 and sigma5 subunits.
AP-5 sigma5 subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	UNKNOWN	Small sigma5 subunit of the heterotetrameric AP-5 adaptor complex. `GO:0044599` GO:0044599 defines human AP-5 as consisting of beta5, zeta, mu5 and sigma5 subunits.

Taxonomic distribution

NCBITaxon:9606 Homo sapiens — COMMON: Hirst et al. identified human AP-5 in HeLa cells, and tagged AP-5 localized to a late endosomal compartment in that system. [DOI:10.1371/journal.pbio.1001170]

Canonical examples

NCBITaxon:9606 Homo sapiens — HeLa-cell model in which AP-5 was identified as a fifth heterotetrameric adaptor complex and connected to late endosomal localization. [DOI:10.1371/journal.pbio.1001170]

Functions

AP-5-associated endosomal sorting — AP-5 is an endosome-associated adaptor complex implicated in sorting cargo through late endosomal compartments.
- DOI:10.1371/journal.pbio.1001170 Hirst et al. 2011 showed that tagged AP-5 localizes to a late endosomal compartment in HeLa cells and that AP-5 subunit knockdown perturbs cation-independent mannose 6-phosphate receptor trafficking and produces swollen endosomal structures with tubules.

Mechanism graphs

Beta5, zeta, mu5 and sigma5 subunits form AP-5 (FUNCTION)

The AP-5 adaptor complex is a heterotetramer associated with endosomal membranes and implicated in endosomal cargo sorting.

Subject	Predicate	Object	Evidence
AP-5 beta5 subunit	is part of	AP-5 adaptor complex	`GO:0044599` GO:0044599 lists beta5 as an AP-5 constituent.
AP-5 zeta subunit	is part of	AP-5 adaptor complex	`GO:0044599` GO:0044599 lists zeta as an AP-5 constituent.
AP-5 mu5 subunit	is part of	AP-5 adaptor complex	`GO:0044599` GO:0044599 lists mu5 as an AP-5 constituent.
AP-5 sigma5 subunit	is part of	AP-5 adaptor complex	`GO:0044599` GO:0044599 lists sigma5 as an AP-5 constituent.
AP-5 adaptor complex	associates with	late endosomal membrane	`GO:0044599` GO:0044599 defines human AP-5 as associated with membranes in the endosomes. `DOI:10.1371/journal.pbio.1001170` Hirst et al. 2011 localized tagged AP-5 to a late endosomal compartment in HeLa cells.
AP-5 adaptor complex	is implicated in	endosomal cargo sorting	`DOI:10.1371/journal.pbio.1001170` Hirst et al. 2011 connected AP-5 subunit knockdown to altered cation-independent mannose 6-phosphate receptor trafficking and swollen endosomal structures with tubules.

Discussions

INTERPRETATION (RESOLVED): Avoid modeling AP-5 as a constitutive clathrin-coat adaptor. GO:0044599 makes AP-5 a child of AP-type membrane coat adaptor complex but explicitly notes that it is unclear whether AP-5 forms clathrin coats in vivo. This record therefore keeps AP-5 under the AP-type parent while avoiding a universal AP-5-to-clathrin-coat edge or a clathrin-coat part_of assertion.
CURATION_TODO (OPEN): Resolve exact source-neutral groundings for the AP-5 beta5, zeta, mu5 and sigma5 subunit classes. GO gives the exact AP-5 complex identity and names its subunit classes, but exact source-neutral InterPro, Pfam or NCBIfam CURIEs for those AP-5-specific classes were not curated in this pass.

Evidence

GO:0044599 Gene Ontology cellular-component term for the AP-5 adaptor complex.
GO:0030119 Gene Ontology cellular-component parent term for AP-type membrane coat adaptor complexes.
DOI:10.1371/journal.pbio.1001170 Hirst et al. 2011, The Fifth Adaptor Protein Complex, PLoS Biology.

Curation history

2026-09-16T14:33:55Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-16T14:35:10Z codex · EXPANDED_RECORD — Added AP-type parentage, the GO exact synonym, reviewed-label-only beta5/zeta/mu5/sigma5 subunits, human HeLa-cell AP-5 distribution and function evidence, GO/DOI evidence, a nonmechanistic AP-5 topology graph, and clathrin-scope and subunit-grounding discussions.
2026-09-16T14:47:12Z codex · ADDRESSED_PR_REVIEW — Clarified the AP-5 human HeLa taxonomic note so AP-5 identification and tagged-AP-5 localization are separate Hirst et al. 2011 findings; addresses PR #1102 review issue #1103.

Source: data/structures/other/ap_5_adaptor_complex.yaml