PSMB5 polyclonal

Catalog #: AB-P243

The proteasome is a large, multimeric protease that catalyzes the final step of the ubiquitin-mediated intracellular protein degradation. The 26S proteasome is an ATP-dependent complex of two copies of the 19S regulator that cap each end of the 20S catalytic core. The 20S is arranged as four axially stacked heptameric rings with multi-catalytic centers located within the internal cavity of the ß-subunits. The 19S caps are composed of 16 different subunits ranging in size from 30 kD to 120 kD and contain ubiquitin chain receptors, ATPase activity and deubiquitinating activities. PSMB5 is a 20S core beta subunit with high similarity to PSMB8. Interferon-γ increases expression of MHC-encoded LMP2/LMP7 (PSMB8) subunits and decreases expression of PSMB5/PSMB6, which alters the proteolytic specificity of proteasomes that may be more appropriate for the immunologic processing of endogenous antigens. Bortezomib, a reversible proteasome inhibitor used in the treatment of refractory multiple myeloma, targets primarily the chymotrypsin-like activity of PSMB5.