PSMF1
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 2VT8, 4OUH
Identifiers
Aliases	PSMF1, PI31, proteasome inhibitor subunit 1
External IDs	OMIM: 617858; MGI: 1346072; HomoloGene: 38231; GeneCards: PSMF1; OMA:PSMF1 - orthologs
Gene location (Human) Chr. Chromosome 20 (human)[1] Band 20p13 Start 1,113,240 bp[1] End 1,189,415 bp[1]
Gene location (Mouse) Chr. Chromosome 2 (mouse)[2] Band 2|2 G3 Start 151,557,732 bp[2] End 151,586,106 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in sperm left testis right testis muscle of thigh blood gastrocnemius muscle popliteal artery tibial arteries monocyte islet of Langerhans Top expressed in seminiferous tubule spermatid secondary oocyte zygote primary oocyte blood sciatic nerve interventricular septum fetal liver hematopoietic progenitor cell spermatocyte More reference expression data BioGPS More reference expression data
Gene ontology Molecular function proteasome binding protein binding endopeptidase inhibitor activity protein homodimerization activity protein heterodimerization activity Cellular component cytoplasm cytosol membrane nucleoplasm endoplasmic reticulum proteasome complex proteasome core complex perinuclear region of cytoplasm Biological process regulation of cellular amino acid metabolic process antigen processing and presentation of exogenous peptide antigen via MHC class I, TAP-dependent ubiquitin-dependent protein catabolic process regulation of mRNA stability positive regulation of canonical Wnt signaling pathway protein polyubiquitination stimulatory C-type lectin receptor signaling pathway tumor necrosis factor-mediated signaling pathway MAPK cascade Fc-epsilon receptor signaling pathway NIK/NF-kappaB signaling negative regulation of proteasomal protein catabolic process anaphase-promoting complex-dependent catabolic process T cell receptor signaling pathway negative regulation of canonical Wnt signaling pathway proteasome-mediated ubiquitin-dependent protein catabolic process Wnt signaling pathway, planar cell polarity pathway negative regulation of endopeptidase activity negative regulation of G2/M transition of mitotic cell cycle protein deubiquitination SCF-dependent proteasomal ubiquitin-dependent protein catabolic process transmembrane transport regulation of transcription from RNA polymerase II promoter in response to hypoxia post-translational protein modification regulation of hematopoietic stem cell differentiation interleukin-1-mediated signaling pathway regulation of mitotic cell cycle phase transition Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 9491 228769 Ensembl ENSG00000125818 ENSMUSG00000032869 UniProt Q92530 Q5QPM9 Q8BHL8 RefSeq (mRNA) NM_006814 NM_178578 NM_178579 NM_001323407 NM_001323408 NM_001323409 NM_001323410 NM_144889 NM_212446 NM_001305244 RefSeq (protein) NP_001310336 NP_001310337 NP_001310338 NP_001310339 NP_006805 NP_848693 NP_001292173 NP_997611 Location (UCSC) Chr 20: 1.11 – 1.19 Mb Chr 2: 151.56 – 151.59 Mb PubMed search [3] [4]
Wikidata
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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. PSMF1 encodes a protein termed PI31 that binds to both 20S and 26S proteasomes. PI31 was originally identified by its ability to inhibit the hydrolysis of small synthetic peptides in a cell free assay, but it stimulates 26S proteasome activity both in vitro and in vivo^[7][8]. PI31 can promote the assembly of 26S proteasomes from 19S and 20S sub-particles, and it also serves as an adapter to couple proteasomes with motor proteins to mediate fast axonal transport in neurons^[9]. Inactivation of PMSF1 in yeast, plants, fruit flies and mice attenuates protein degradation and stimulates accumulation of ubiquitinated protein aggregates. Furthermore, loss of PSMF1 function in mice causes progressive neuronal dysfunction, synaptic degeneration and eventually neuronal cell death^[10]. Alternative transcript variants have been identified for this gene.^[6]