proteasome accessory complex

GO:0022624 · Other · Multiprotein complex · Proposed

A protein complex, that caps one or both ends of the proteasome core complex and regulates entry into, or exit from, the proteasome core complex. [GO:0022624]

Part of: proteasome complex (GO:0000502)

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

Taxonomic distribution

• NCBITaxon:2157 Archaea — COMMON: Archaeal 20S proteasome cores associate with proteasome-associated nucleotidases such as PAN to unfold and translocate substrates. [DOI:10.1042/ETLS20180025]
• NCBITaxon:201174 Actinomycetota — VARIABLE: Actinobacterial proteasome systems include 20S cores with alternative regulators such as Mpa, Bpa, or Cpa. [DOI:10.3389/fmolb.2019.00023]
• NCBITaxon:2759 Eukaryota — COMMON: Eukaryotic 26S proteasomes are built from 20S core particles capped by 19S regulatory particles. [DOI:10.1146/annurev-biochem-060410-150257]

Canonical examples

• NCBITaxon:83332 Mycobacterium tuberculosis H37Rv — Actinobacterial model in which Mpa and Bpa regulator routes connect substrate recruitment to the 20S proteasome core. [DOI:10.3389/fmolb.2019.00023]

Functions

• proteasome core access regulation — Proteasome accessory complexes cap 20S core particles and regulate substrate entry into, or product exit from, the proteolytic chamber.
  • GO:0022624 GO:0022624 defines proteasome accessory complexes as caps that regulate entry into, or exit from, the proteasome core complex.
  • DOI:10.3389/fmolb.2019.00023 Muller and Weber-Ban 2019 review bacterial regulator complexes that associate with the 20S core to recruit and internalize substrates.

Mechanism graphs

Accessory complexes cap the 20S proteasome core (FUNCTION)

Proteasome accessory complexes bind the ends of the 20S proteolytic core and control access to the gated proteolytic chamber.

Discussions

• INTERPRETATION (RESOLVED): Should 19S, PAN, PA28, Mpa, Bpa, or Cpa families be listed as components of the generic proteasome accessory complex? GO:0022624 groups alternative proteasome caps and regulators. Those eukaryotic, archaeal, and actinobacterial accessory families do not share one curated source-neutral component set.

Evidence

• GO:0022624 Gene Ontology cellular-component term for the proteasome accessory complex.
• GO:0032991 Gene Ontology cellular-component parent term for protein-containing complex.
• GO:0000502 Gene Ontology cellular-component term for the containing proteasome complex.
• GO:0005839 Gene Ontology cellular-component term for the capped proteasome core complex.
• DOI:10.1042/ETLS20180025 Maupin-Furlow 2018, Proteolytic systems of archaea: slicing, dicing, and mincing in the extreme, Emerging Topics in Life Sciences.
• DOI:10.3389/fmolb.2019.00023 Muller and Weber-Ban 2019, The bacterial proteasome at the core of diverse degradation pathways, Frontiers in Molecular Biosciences.
• DOI:10.1146/annurev-biochem-060410-150257 Tomko and Hochstrasser 2013, Molecular Architecture and Assembly of the Eukaryotic Proteasome, Annual Review of Biochemistry.

Curation history

• 2026-09-15T21:54:43Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
• 2026-09-15T21:55:34Z codex · EXPANDED_RECORD — Added GO parentage and proteasome parthood, archaeal, actinobacterial, and eukaryotic scope, an M. tuberculosis example, core-access regulation evidence, a nonmechanistic accessory-capped-core graph, and a resolved boundary interpretation for family-specific accessory subunits.
• 2026-09-15T22:06:46Z codex · REVIEW_FIXES — Addressed PR #1030 review issues #1031 and #1032 by aligning graph predicate strings with the whole-proteasome graph and removing descendant/child wording from the accessory-family boundary discussion.

Source: data/structures/other/proteasome_accessory_complex.yaml