Proteasome Subunit Alpha Type 5 (PSMA5) Human Recombinant Protein

The proteasome is a multicatalytic proteinase complex with a highly ordered ring-shaped 20S core structure. The core structure 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. 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 member of the peptidase T1A family, that is a 20S core alpha subunit. Multiple alternatively spliced transcript variants encoding two distinct isoforms have been found for this gene. [provided by RefSeq, Dec 2010]

PSMA5: 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.

Protein type: Protease; Proteasome complex; EC 3.4.25.1

Chromosomal Location of Human Ortholog: 1p13

Cellular Component: nucleoplasm; proteasome complex; proteasome core complex; cytoplasm; nucleus; cytosol

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; 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; 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; antigen processing and presentation of exogenous peptide antigen via MHC class I; gene expression; mitotic cell cycle; regulation of amino acid metabolic process; negative regulation of apoptosis; G1/S transition of mitotic cell cycle