PSMB8 - Proteasome subunit beta type-8 - human protein (Function)
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PSMB8 »  Proteasome subunit beta type-8   [ EC ]
Protein also known as:  Multicatalytic endopeptidase complex subunit C13.
Gene name:  PSMB8
Family name: Peptidase T1B
Entry whose protein(s) existence is based on evidence at protein level
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The proteasome is a multicatalytic proteinase complex which is characterized by its ability to cleave peptides with Arg, Phe, Tyr, Leu, and Glu adjacent to the leaving group at neutral or slightly basic pH. The proteasome has an ATP-dependent proteolytic activity. This subunit is involved in antigen processing to generate class I binding peptides. Replacement of PSMB5 by PSMB8 increases the capacity of the immunoproteasome to cleave model peptides after hydrophobic and basic residues. Acts as a major component of interferon gamma-induced sensitivity. Plays a key role in apoptosis via the degradation of the apoptotic inhibitor MCL1. May be involved in the inflammatory response pathway. In cancer cells, substitution of isoform 1 (E2) by isoform 2 (E1) results in immunoproteasome deficiency. Required for the differentiation of preadipocytes into adipocytes.  
  • UniProtKB
GO molecular function 
Endopeptidase activitydefinition[GO:0004175]  
  • RefGenome
Protein bindingdefinition[GO:0005515]  
  • IntAct
Threonine-type endopeptidase activitydefinition[GO:0004298]  
  • UniProtKB KW
GO biological process 
Fat cell differentiationdefinition[GO:0045444]  
  • UniProtKB
Proteasomal ubiquitin-independent protein catabolic processdefinition[GO:0010499]  
  • RefGenome
Proteasome-mediated ubiquitin-dependent protein catabolic processdefinition[GO:0043161]  
  • RefGenome
Enzymatic activity 
This protein acts as an enzyme. It is known to catalyze the following reaction
EC Cleavage of peptide bonds with very broad specificity.  
  • UniProtKB
More information is available from:
According to KEGG, this protein belongs to the following pathway:
Proteasome  hsa03050+5696  
According to Reactome, this protein belongs to the following pathways:
Activation of NF-kappaB in B cells  R-HSA-1169091  
Antigen processing: Ubiquitination & Proteasome degradation  R-HSA-983168  
APC/C:Cdc20 mediated degradation of Securin  R-HSA-174154  
APC/C:Cdh1 mediated degradation of Cdc20 and other APC/C:Cdh1 targeted proteins in late mitosis/early G1  R-HSA-174178  
Asymmetric localization of PCP proteins  R-HSA-4608870  
AUF1 (hnRNP D0) binds and destabilizes mRNA  R-HSA-450408  
Autodegradation of Cdh1 by Cdh1:APC/C  R-HSA-174084  
Autodegradation of the E3 ubiquitin ligase COP1  R-HSA-349425  
Cdc20:Phospho-APC/C mediated degradation of Cyclin A  R-HSA-174184  
CDK-mediated phosphorylation and removal of Cdc6  R-HSA-69017  
CDT1 association with the CDC6:ORC:origin complex  R-HSA-68827  
CLEC7A (Dectin-1) signaling  R-HSA-5607764  
Cross-presentation of soluble exogenous antigens (endosomes)  R-HSA-1236978  
Dectin-1 mediated noncanonical NF-kB signaling  R-HSA-5607761  
Degradation of AXIN  R-HSA-4641257  
Degradation of beta-catenin by the destruction complex  R-HSA-195253  
Degradation of DVL  R-HSA-4641258  
Degradation of GLI1 by the proteasome  R-HSA-5610780  
Degradation of GLI2 by the proteasome  R-HSA-5610783  
Downstream TCR signaling  R-HSA-202424  
ER-Phagosome pathway  R-HSA-1236974  
FCERI mediated NF-kB activation  R-HSA-2871837  
GLI3 is processed to GLI3R by the proteasome  R-HSA-5610785  
Hedgehog 'on' state  R-HSA-5632684  
Hedgehog ligand biogenesis  R-HSA-5358346  
Hh mutants that don't undergo autocatalytic processing are degraded by ERAD  R-HSA-5362768  
Interferon alpha/beta signaling  R-HSA-909733  
MAPK6/MAPK4 signaling  R-HSA-5687128  
NIK-->noncanonical NF-kB signaling  R-HSA-5676590  
Orc1 removal from chromatin  R-HSA-68949  
Regulation of activated PAK-2p34 by proteasome mediated degradation  R-HSA-211733  
Regulation of ornithine decarboxylase (ODC)  R-HSA-350562  
Regulation of RAS by GAPs  R-HSA-5658442  
SCF(Skp2)-mediated degradation of p27/p21  R-HSA-187577  
SCF-beta-TrCP mediated degradation of Emi1  R-HSA-174113  
Separation of Sister Chromatids  R-HSA-2467813  
TNFR2 non-canonical NF-kB pathway  R-HSA-5668541  
Ubiquitin Mediated Degradation of Phosphorylated Cdc25A  R-HSA-69601  
Ubiquitin-dependent degradation of Cyclin D1  R-HSA-69229  
Vif-mediated degradation of APOBEC3G  R-HSA-180585  
Vpu mediated degradation of CD4  R-HSA-180534  


Biological process 
Differentiation  definition   [KW-0221]
Host-virus interaction  definition   [KW-0945]
Immunity  definition   [KW-0391]
Molecular function 
Hydrolase  definition   [KW-0378]
Protease  definition   [KW-0645]
Threonine protease  definition   [KW-0888]
Technical term 
Reference proteome  definition   [KW-1185]

Further external links

GeneWiki: PSMB8
GenomeRNAi: 5696
PRO: PR:P28062