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Proteasome (prosome, macropain) 26S subunit, ATPase, 3
Symbols PSMC3 ; TBP1
External IDs OMIM186852 MGI1098754 HomoloGene2097 GeneCards: PSMC3 Gene
RNA expression pattern
PBB GE PSMC3 201267 s at tn.png
More reference expression data
Species Human Mouse
Entrez 5702 19182
Ensembl ENSG00000165916 ENSMUSG00000002102
UniProt P17980 O88685
RefSeq (mRNA) NM_002804 NM_008948
RefSeq (protein) NP_002795 NP_032974
Location (UCSC) Chr 11:
47.44 – 47.45 Mb
Chr 2:
91.05 – 91.07 Mb
PubMed search [1] [2]

26S protease regulatory subunit 6A is an enzyme that in humans is encoded by the PSMC3 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. This gene encodes one of the ATPase subunits, a member of the triple-A family of ATPases that have chaperone-like activity. This subunit may compete with PSMC2 for binding to the HIV tat protein to regulate the interaction between the viral protein and the transcription complex. A pseudogene has been identified on chromosome 9.[3]


PSMC3 has been shown to interact with PSMC5[4] and Von Hippel-Lindau tumor suppressor.[5]


  1. ^ Hoyle J, Tan KH, Fisher EM (Mar 1997). "Localization of genes encoding two human one-domain members of the AAA family: PSMC5 (the thyroid hormone receptor-interacting protein, TRIP1) and PSMC3 (the Tat-binding protein, TBP1)". Hum Genet 99 (2): 285–8. doi:10.1007/s004390050356. PMID 9048938. 
  2. ^ Tanahashi N, Suzuki M, Fujiwara T, Takahashi E, Shimbara N, Chung CH et al. (Mar 1998). "Chromosomal localization and immunological analysis of a family of human 26S proteasomal ATPases". Biochem Biophys Res Commun 243 (1): 229–32. doi:10.1006/bbrc.1997.7892. PMID 9473509. 
  3. ^ "Entrez Gene: PSMC3 proteasome (prosome, macropain) 26S subunit, ATPase, 3". 
  4. ^ Ishizuka T, Satoh T, Monden T, Shibusawa N, Hashida T, Yamada M et al. (Aug 2001). "Human immunodeficiency virus type 1 Tat binding protein-1 is a transcriptional coactivator specific for TR". Mol. Endocrinol. 15 (8): 1329–43. doi:10.1210/mend.15.8.0680. PMID 11463857. 
  5. ^ Corn PG, McDonald ER, Herman JG, El-Deiry WS (Nov 2003). "Tat-binding protein-1, a component of the 26S proteasome, contributes to the E3 ubiquitin ligase function of the von Hippel-Lindau protein". Nat. Genet. 35 (3): 229–37. doi:10.1038/ng1254. PMID 14556007. 

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