Component of the 20S core proteasome complex involved in the proteolytic degradation of most intracellular proteins. This complex plays numerous essential roles within the cell by associating with different regulatory particles. Associated with two 19S regulatory particles, forms the 26S proteasome and thus participates in the ATP-dependent degradation of ubiquitinated proteins. The 26S proteasome plays a key role in the maintenance of protein homeostasis by removing misfolded or damaged proteins that could impair cellular functions, and by removing proteins whose functions are no longer required. Associated with the PA200 or PA28, the 20S proteasome mediates ubiquitin-independent protein degradation. This type of proteolysis is required in several pathways including spermatogenesis (20S-PA200 complex) or generation of a subset of MHC class I-presented antigenic peptides (20S-PA28 complex). Inhibits the transactivation function of HIF-1A under both normoxic and hypoxia-mimicking conditions. The interaction with EMAP2 increases the proteasome-mediated HIF-1A degradation under the hypoxic conditions. Plays a role in hepatitis C virus internal ribosome entry site-mediated translation. Mediates nuclear translocation of the androgen receptor (AR) and thereby enhances androgen-mediated transactivation. Promotes MAVS degradation and thereby negatively regulates MAVS-mediated innate immune response. The 26S proteasome consists of a 20S proteasome core and two 19S regulatory subunits. The 20S proteasome core is a barrel-shaped complex made of 28 subunits that are arranged in four stacked rings. The two outer rings are each formed by seven alpha subunits, and the two inner rings are formed by seven beta subunits. The proteolytic activity is exerted by three beta-subunits PSMB5, PSMB6 and PSMB7. PSMA7 interacts directly with the PSMG1-PSMG2 heterodimer which promotes 20S proteasome assembly. Interacts with HIF1A. Interacts with RAB7A. Interacts with PRKN. Interacts with ABL1 and ABL2. Interacts with EMAP2. Interacts with MAVS. Belongs to the peptidase T1A family.