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Proteasome (prosome, macropain) activator subunit 3 (PA28 gamma; Ki)
Symbols PSME3 ; HEL-S-283; Ki; PA28-gamma; PA28G; PA28gamma; REG-GAMMA
External IDs OMIM605129 MGI1096366 HomoloGene2111 GeneCards: PSME3 Gene
RNA expression pattern
PBB GE PSME3 200988 s at tn.png
PBB GE PSME3 200987 x at tn.png
PBB GE PSME3 209852 x at tn.png
More reference expression data
Species Human Mouse
Entrez 10197 19192
Ensembl ENSG00000131467 ENSMUSG00000078652
UniProt P61289 P61290
RefSeq (mRNA) NM_001267045 NM_011192
RefSeq (protein) NP_001253974 NP_035322
Location (UCSC) Chr 17:
40.98 – 41 Mb
Chr 11:
101.32 – 101.32 Mb
PubMed search [1] [2]

Proteasome activator complex subunit 3 is a protein that in humans is encoded by the PSME3 gene.[1][2]


The 26S proteasome is a multicatalytic proteinase complex with a highly ordered structure composed of 2 complexes, a 20S core and a 19S regulator. The 20S core is composed of 4 rings of 28 non-identical subunits; 2 rings are composed of 7 alpha subunits and 2 rings are composed of 7 beta subunits. The 19S regulator is composed of a base, which contains 6 ATPase subunits and 2 non-ATPase subunits, and a lid, which contains up to 10 non-ATPase subunits. Proteasomes are distributed throughout eukaryotic cells at a high concentration and cleave peptides in an ATP/ubiquitin-dependent process in a non-lysosomal pathway. An essential function of a modified proteasome, the immunoproteasome, is the processing of class I MHC peptides. The immunoproteasome contains an alternate regulator, referred to as the 11S regulator or PA28, that replaces the 19S regulator. Three subunits (alpha, beta and gamma) of the 11S regulator have been identified. This gene encodes the gamma subunit of the 11S regulator. Six gamma subunits combine to form a homohexameric ring. Two transcript variants encoding different isoforms have been identified.[2]


PSME3 has been shown to interact with P53[3] and Mdm2.[3]


  1. ^ Albertsen HM, Smith SA, Mazoyer S, Fujimoto E, Stevens J, Williams B et al. (Dec 1994). "A physical map and candidate genes in the BRCA1 region on chromosome 17q12-21". Nat Genet 7 (4): 472–9. doi:10.1038/ng0894-472. PMID 7951316. 
  2. ^ a b "Entrez Gene: PSME3 proteasome (prosome, macropain) activator subunit 3 (PA28 gamma; Ki)". 
  3. ^ a b Zhang Z, Zhang R (Mar 2008). "Proteasome activator PA28 gamma regulates p53 by enhancing its MDM2-mediated degradation". EMBO J. 27 (6): 852–64. doi:10.1038/emboj.2008.25. PMC 2265109. PMID 18309296. 

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