Fig. 2

Schematic of 20S proteasome inhibitors and their targets. Most proteasome inhibitors (in red boxes) target the common β5 chymotrypsin-like site of the 20S CP as it is the most important active site for protein breakdown. MG132 is the first proteasome inhibitor developed. The first-in-class proteasome inhibitor bortezomib and other second-generation proteasome inhibitors were later developed with enhanced potency and specificity for more active sites. Functional inhibition of the proteasome results in activation of pro-apoptotic and suppression of oncogenic pathways