20S Immunoproteasome (human) (untagged)

The 20S immunoproteasome is structurally similar to constitutive 26S proteasome. The 20S core of immunoproteasome contains two outer rings composed of alpha-subunits, and two internal 7-subunit containing rings each possessing 3 specific subunits responsible for proteasome catalytic activity. In immunoproteasomes these subunits (ß1, ß2, ß5) are replaced by three inducible subunits: PSMB9, PSMB10 and PSMB8, (ß1i, ß2i, ß5i). These stress-induced subunits allow for the production of MHC-1 associating peptides, which are displayed as antigens on the cell surface. These displayed peptides can then be recognized by immune surveillance CD8 T cells. 20S immunoproteasome is recognized as a strong drug target for autoimmune disease and cancer.