Proteasome subunit beta type-1 (PSMB6) and Proteasome subunit beta type-2 (PSMB7) (PSMB6/PSMB7)

The 26S proteasome is a large, ATP-dependent multi-protein complex that serves as the primary machinery for regulated protein degradation in eukaryotic cells (UniProt P28072). The catalytic activity of the proteasome is localized within the 20S core particle, which contains three distinct pairs of active sites: the beta 1 (caspase-like), beta 2 (trypsin-like), and beta 5 (chymotrypsin-like) subunits (PMID: 29129455). While the beta 5 subunit is the primary target for most FDA-approved proteasome inhibitors, the beta 1 and beta 2 subunits (encoded by PSMB6 and PSMB7) are essential co-targets that contribute to the overall proteolytic capacity of the cell. Inhibition of these subunits disrupts the ubiquitin-proteasome system, leading to the accumulation of misfolded or regulatory proteins, which triggers the unfolded protein response and promotes apoptosis in malignant cells (PMID: 21685910). This mechanism is particularly effective in treating plasma cell dyscrasias like multiple myeloma, where high protein synthesis rates make cells hypersensitive to proteasome inhibition (StatPearls NBK542311). Additionally, these subunits play a role in the immunoproteasome, making them relevant targets for modulating immune responses and inflammation (PubMed Central PMC3544431).

Other names

26S proteasome beta 1 and beta 2 subunitsPSMB6PSMB7Proteasome catalytic subunits beta 1 and 2C7-IZ subunit20S proteasome beta 1 subunit20S proteasome beta 2 subunit

Inhibition of the threonine protease activity of the 20S proteasome core, leading to the accumulation of ubiquitinated proteins and induction of apoptosis (PMID: 29129455).