PSMA7
Description
The PSMA7 (proteasome 20S subunit alpha 7) is a protein-coding gene located on chromosome 20.
PSMA7, also known as Proteasome subunit alpha type-7 or 20S proteasome subunit alpha-4, is a protein encoded by the PSMA7 gene. It is one of the 17 essential subunits that make up the 20S proteasome complex, which recognizes and degrades damaged proteins and key regulatory proteins. As a component of the alpha ring, PSMA7 contributes to the formation of the heptameric alpha rings and the substrate entrance gate. This subunit plays a critical role in the assembly of the 19S base and 20S. PSMA7 has been shown to interact with the hepatitis B virus X protein, essential for viral replication, and is involved in regulating hepatitis C virus internal ribosome entry site (IRES) activity, also vital for viral replication. PSMA7 also regulates hypoxia-inducible factor-1alpha (HIF-1alpha), a transcription factor important for cellular responses to oxygen tension. Recent studies on E3 ligase Parkin-related neurodegeneration have identified PSMA7 as a Parkin-associating partner, with interaction occurring between the C-terminal domain of Parkin and the C-terminal of PSMA7.
PSMA7 is a component of the 20S proteasome, a complex responsible for degrading most intracellular proteins. It plays essential roles by associating with different regulatory particles. With two 19S regulatory particles, PSMA7 forms the 26S proteasome, which degrades ubiquitinated proteins in an ATP-dependent manner. This process maintains protein homeostasis by removing misfolded or damaged proteins and those no longer needed. PSMA7 can also associate with PA200 or PA28, enabling ubiquitin-independent protein degradation essential for processes like spermatogenesis (20S-PA200) and MHC class I antigen presentation (20S-PA28). PSMA7 inhibits the activity of HIF-1A, a transcription factor involved in oxygen regulation, under both normal and low oxygen conditions. Its interaction with EMAP2 enhances HIF-1A degradation under low oxygen. PSMA7 also plays a role in hepatitis C virus translation and promotes nuclear translocation of the androgen receptor, enhancing androgen signaling. PSMA7 negatively regulates innate immune responses by promoting MAVS degradation.
PSMA7 is also known as C6, HEL-S-276, HSPC, RC6-1, XAPC7.
