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. The 26S proteasome consists of a 20S proteasome core and two 19S regulatory subunits. The 20S proteasome core is composed of 28 subunits that are arranged in four stacked rings, resulting in a barrel-shaped structure. The two end rings are each formed by seven alpha subunits, and the two central rings are each formed by seven beta subunits. The catalytic chamber with the active sites is on the inside of the barrel. PSMA5 interacts directly with the PSMG1-PSMG2 heterodimer which promotes 20S proteasome assembly. Up-regulated in colon cancer cell lines. Up-regulated in fetal Down syndrome (DS) brain. May be the target of the transcriptional activator NFE2L2. Expressed in fetal brain. Belongs to the peptidase T1A family. Note: This description may include information from UniProtKB.
Protein type: EC 18.104.22.168; Proteasome complex; Protease
Molecular Function: threonine endopeptidase activity; protein binding
Biological Process: positive regulation of ubiquitin-protein ligase activity during mitotic cell cycle; negative regulation of ubiquitin-protein ligase activity during mitotic cell cycle; protein polyubiquitination; viral reproduction; apoptosis; M/G1 transition of mitotic cell cycle; antigen processing and presentation of exogenous peptide antigen via MHC class I, TAP-dependent; DNA damage response, signal transduction by p53 class mediator resulting in cell cycle arrest; mRNA metabolic process; regulation of apoptosis; antigen processing and presentation of peptide antigen via MHC class I; regulation of ubiquitin-protein ligase activity during mitotic cell cycle; anaphase-promoting complex-dependent proteasomal ubiquitin-dependent protein catabolic process; RNA metabolic process; antigen processing and presentation of exogenous peptide antigen via MHC class I; gene expression; mitotic cell cycle; S phase of mitotic cell cycle; regulation of amino acid metabolic process; cell cycle checkpoint; G1/S transition of mitotic cell cycle
SS: The number of records in which this modification site was determined using site-specific methods. SS methods include amino acid sequencing, site-directed mutagenesis, modification site-specific antibodies, specific MS strategies, etc.