Proteasome subunit (None)

The proteasome is a large, multisubunit protease complex essential for regulated protein degradation in eukaryotic cells. It exists primarily as the 26S proteasome, composed of a 20S core particle and one or two 19S regulatory particles. The 20S core contains multiple alpha and beta subunits arranged in stacked rings, with three main catalytic beta subunits (β1 with caspase-like, β2 with trypsin-like, and β5 with chymotrypsin-like activity) responsible for degrading most polyubiquitinated proteins. The proteasome is a central player in protein homeostasis, cell cycle regulation, apoptosis, immune surveillance, and neural signaling. Proteasome inhibition is an established cancer therapy mechanism, but the generic term “proteasome subunit” is imprecise as there are at least fourteen core subunits, each with distinct names and functions. For drug targeting and annotation, it is important to specify the unique subunit(s) of interest. Note: The use of “Proteasome subunit” as a generic target is not recommended due to lack of specificity. Established reference requires precise names for each individual subunit involved.

Inhibition of proteolytic activity of specific catalytic subunits (primarily β5, and to a lesser extent β1 and β2), blocking degradation of polyubiquitinated proteins and thereby inducing apoptosis in rapidly dividing cells. Prevention of degradation of regulatory proteins involved in cell cycle and apoptosis (stabilizing p53, cyclins, etc.). Modulation of NF-κB pathway via stabilization of its inhibitor IκB.