Proteasome subunit alpha type-5 (PSMA5)

Proteasome subunit alpha type-5 (PSMA5) is a core, non-catalytic component of the 20S proteasome complex, which is essential for ATP-dependent, ubiquitin-mediated degradation of most intracellular proteins and for protein homeostasis in all eukaryotic cells. The 20S proteasome is formed by four stacked rings of subunits; PSMA5 is one of the seven alpha subunits forming the outer rings and contributing to the gate that regulates access to the proteolytic chamber. PSMA5 is involved in critical biological functions, including regulation of the cell cycle, protein quality control, and antigen presentation via the immunoproteasome. Aberrant expression or mutation of PSMA5 is implicated in cancers (due to enhanced protein degradation and drug resistance), autoinflammatory diseases, and degenerative conditions. PSMA5 has been identified as a potential therapeutic target for proteasome inhibitors used in cancer treatment and is also emerging as a biomarker for drug resistance and prognosis in several malignancies.

Other names

Proteasome 20S subunit alpha 5alpha-5ZETAMacropain zeta chainMulticatalytic endopeptidase complex zeta chainProteasome subunit alpha-5Proteasome zeta chainPSC5epididymis tissue sperm binding protein Li 11nmacropain subunit zetaproteasome component 5

Inhibition of the proteasome core particle (e.g., by bortezomib, blocks protein degradation, induces apoptosis); Sensitization to chemotherapeutics or apoptosis upon PSMA5 knockdown