PSMA11

PSMA11, or proteasome subunit alpha type-11, is a protein encoded by the PSMA11 gene. It is a member of the proteasome alpha family, a group of subunits that form the outer rings of the 20S proteasome core particle, a central component of the ubiquitin-proteasome system.

Function: As part of the 20S core, PSMA11 contributes to the assembly and structural stability of the proteasome and helps form the open gate that regulates substrate entry into the proteolytic chamber. The proteolytic activity is carried out by the beta subunits, while the alpha subunits primarily control access and gating.

Structure and evolution: PSMA11 is a conserved eukaryotic proteasome alpha subunit. It participates in the formation of the heptameric rings that comprise the proteasome core and interacts with neighboring alpha subunits during assembly.

Expression and localization: PSMA11 is expressed in many tissues as part of the constitutively active proteasome. Proteasome components are essential for regular protein turnover and cellular homeostasis.

Interactions and complexes: During assembly, PSMA11 associates with other proteasome alpha subunits (such as PSMA1–PSMA7) to form the 20S core, which can associate with regulatory particles like the 19S to form the 26S proteasome under certain cellular conditions.

Clinical significance: Alterations in proteasome subunits can impact proteostasis and are studied in relation to cancer, neurodegeneration, and immune function. Specific contributions of PSMA11 are the subject of ongoing research.

See also: Proteasome, Proteasome subunit alpha type family, Ubiquitin-proteasome system.