Proteasome 20S core particle (20S proteasome)

The proteasome 20S core particle is a highly conserved, cylindrical, multi-subunit protease complex at the center of the cellular protein degradation machinery in eukaryotes[1][2][3][4][6]. It consists of four stacked heptameric rings arranged in an α_7–β_7–β_7–α_7 configuration, creating a central proteolytic chamber where protein substrates are degraded into short peptides[1][2][3][4]. The two outer α rings form gated entry points that control substrate access, while the two inner β rings contain the proteolytic active sites. Three β subunits (β1, β2, β5) confer caspase-like, trypsin-like, and chymotrypsin-like activities, respectively[1][6][4]. The 20S core particle can act independently or as part of the larger 26S proteasome complex when capped with regulatory particles that recognize ubiquitinated substrates[2][5]. Through its central role in regulated protein degradation, the 20S proteasome core is essential for cellular homeostasis, quality control, immune surveillance (via antigen processing), cell cycle regulation, and stress responses. Inhibition of the 20S core's activity is a validated therapeutic strategy for various cancers—notably multiple myeloma—and the core is overactive or dysfunctional in many diseases involving abnormal protein homeostasis[5][6][8].

Other names

20S proteasome20S core particle20S CP20S core complex

Inhibition of proteolytic activity, leading to accumulation of polyubiquitinated proteins and induction of apoptosis in cancer cells[5][6]. Disruption of protein homeostasis and cell cycle arrest