REGγ, also named Ki antigen, PSME3, PA28γ, or 11Sγ, was first found in the serum of patients with systemic lupus erythematosus and could regulate proteolysis in a ubiquitin-independent pathway by activating the 20S proteasome (30, 31). This evidence concerns the gene PSME3 and systemic lupus erythematosus.