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Available structures
PDB Ortholog search: PDBe RCSB
Aliases PSMF1, PI31, proteasome inhibitor subunit 1
External IDs MGI: 1346072 HomoloGene: 38231 GeneCards: PSMF1
Gene location (Human)
Chromosome 20 (human)
Chr. Chromosome 20 (human)[1]
Chromosome 20 (human)
Genomic location for PSMF1
Genomic location for PSMF1
Band 20p13 Start 1,113,263 bp[1]
End 1,189,415 bp[1]
RNA expression pattern
PBB GE PSMF1 201052 s at fs.png

PBB GE PSMF1 201053 s at fs.png
More reference expression data
Species Human Mouse
RefSeq (mRNA)


RefSeq (protein)


Location (UCSC) Chr 20: 1.11 – 1.19 Mb Chr 20: 151.72 – 151.74 Mb
PubMed search [3] [4]
View/Edit Human View/Edit Mouse

Proteasome inhibitor PI31 subunit is a protein that in humans is encoded by the PSMF1 gene.[5][6]


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 a protein that inhibits the activation of the proteasome by the 11S and 19S regulators. Alternative transcript variants have been identified for this gene.[6]


  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000125818 - Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000032869 - Ensembl, May 2017
  3. ^ "Human PubMed Reference:". 
  4. ^ "Mouse PubMed Reference:". 
  5. ^ Tanahashi N, Kawahara H, Murakami Y, Tanaka K (Apr 1999). "The proteasome-dependent proteolytic system". Molecular Biology Reports. 26 (1–2): 3–9. doi:10.1023/A:1006909522731. PMID 10363639. 
  6. ^ a b "Entrez Gene: PSMF1 proteasome (prosome, macropain) inhibitor subunit 1 (PI31)". 

Further reading[edit]