PSMC3
Description
The PSMC3 (proteasome 26S subunit, ATPase 3) is a protein-coding gene located on chromosome 11.
PSMC3, also known as 26S proteasome regulatory subunit 6A or 26S proteasome AAA-ATPase subunit Rpt5, is an enzyme encoded by the human PSMC3 gene. This protein is one of the 19 essential subunits of the complete 19S proteasome complex. Six 26S proteasome AAA-ATPase subunits, including Rpt5 (PSMC3), together with four non-ATPase subunits, form the base subcomplex of the 19S regulatory particle for the proteasome complex. The PSMC3 gene encodes an ATPase subunit, a member of the triple-A family of ATPases, known for their chaperone-like activity. This subunit may compete with PSMC2 for binding to the HIV tat protein, regulating the interaction between the viral protein and the transcription complex. A pseudogene has been identified on chromosome 9. The human PSMC3 gene has 12 exons and is located at chromosome band 11p11.2. The human protein 26S protease regulatory subunit 6A is 49kDa in size and composed of 439 amino acids. The calculated theoretical pI of this protein is 5.68. The 26S proteasome complex usually consists of a 20S core particle (CP) and one or two 19S regulatory particles (RP) on either one side or both sides of the barrel-shaped 20S. The CP and RPs have distinct structural characteristics and biological functions. The 20S subcomplex exhibits three types of proteolytic activities: caspase-like, trypsin-like, and chymotrypsin-like activities.
PSMC3 is a component of the 26S proteasome, a multiprotein complex responsible for the ATP-dependent degradation of ubiquitinated proteins. This complex maintains protein homeostasis by removing misfolded or damaged proteins, preventing cellular dysfunction, and clearing proteins with obsolete functions. The proteasome is crucial for various cellular processes, including cell cycle progression, apoptosis, and DNA damage repair. PSMC3 is part of a heterohexameric ring of AAA (ATPases associated with diverse cellular activities) proteins that unfolds ubiquitinated target proteins. These unfolded proteins are then translocated into a proteolytic chamber within the proteasome, where they are degraded into peptides.
PSMC3 is also known as DCIDP, RPT5, TBP1.
