PSME1 cDNA Clone – Proteasome (Prosome, Macropain) Activator Subunit 1 (PA28 Alpha) (Human)

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. The immunoproteasome contains an alternate regulator, referred to as the 11S regulator or PA28, that replaces the 19S regulator. Three subunits (alpha, beta and gamma) of the 11S regulator have been identified. This gene encodes the alpha subunit of the 11S regulator, one of the two 11S subunits that is induced by gamma-interferon. Three alpha and three beta subunits combine to form a heterohexameric ring. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2013]

PSME1: Implicated in immunoproteasome assembly and required for efficient antigen processing. The PA28 activator complex enhances the generation of class I binding peptides by altering the cleavage pattern of the proteasome. Heterodimer of PSME1 and PSME2, which forms a hexadimeric ring. PSME1 can form homoheptamers. By IFNG/IFN-gamma. Belongs to the PA28 family.

Protein type: Proteasome complex

Chromosomal Location of Human Ortholog: 14q11.2

Cellular Component: cytoplasm; cytosol; nucleoplasm; proteasome complex

Biological Process: anaphase-promoting complex-dependent proteasomal ubiquitin-dependent protein catabolic process; antigen processing and presentation of exogenous peptide antigen via MHC class I, TAP-dependent; MAPKKK cascade; negative regulation of ubiquitin-protein ligase activity during mitotic cell cycle; positive regulation of ubiquitin-protein ligase activity during mitotic cell cycle; proteasomal ubiquitin-dependent protein catabolic process; protein polyubiquitination; regulation of amino acid metabolic process; regulation of mRNA stability; stimulatory C-type lectin receptor signaling pathway; T cell receptor signaling pathway; tumor necrosis factor-mediated signaling pathway; Wnt receptor signaling pathway, planar cell polarity pathway