PSMB4
Function
Non-catalytic 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). SMAD1/OAZ1/PSMB4 complex mediates the degradation of the CREBBP/EP300 repressor SNIP1.
Involvement in disease
Proteasome-associated autoinflammatory syndrome 3
PRAAS3
An autoinflammatory disorder characterized by onset in early infancy and recurrent fever, nodular dermatitis, myositis, panniculitis-induced lipodystrophy, lymphadenopathy, and immune dysregulation. Variable accompanying features may include joint contractures, hepatosplenomegaly, anemia, thrombocytopenia, recurrent infections, autoantibodies, and hypergammaglobulinemia. Some patients may have intracranial calcifications. PRAAS3 inheritance is autosomal recessive or digenic.
None
The disease is caused by variants affecting distinct genetic loci, including the gene represented in this entry.
Sequence Similarities
Belongs to the peptidase T1B family.
Cellular localization
- Cytoplasm
- Nucleus
- Translocated from the cytoplasm into the nucleus following interaction with AKIRIN2, which bridges the proteasome with the nuclear import receptor IPO9.
Alternative names
PROS26, PSMB4, Proteasome subunit beta type-4, 26 kDa prosomal protein, Macropain beta chain, Multicatalytic endopeptidase complex beta chain, Proteasome beta chain, Proteasome chain 3, Proteasome subunit beta-7, HsBPROS26, PROS-26, HsN3, beta-7