Proteasome activator PA28γ,also known as Ki antigen,REGγ or PSME3,is first found as Ki antigen in the serum of a patient with systemic lupus erythematosus,which belongs to 11S proteasome activator family together with PA28α and PA28β.In the amino acid sequence,PA28γ has 25%homology with PA28α and PA28β and its seven-subunit homomer is a 20S proteasome acti-vator,which mainly exists in the nucleus and participates in ubiquitin and ATP-dependent or independent protein degradation.More and more studies have reported the role of PA28γ in human immune-related diseases.This article reviews the function of PA28γ as a proteasome activator and its role in immune-related diseases including cancer,inflammation and virus infection-related diseases and other diseases in recent years,so as to reveal the role of PA28γ in the occurrence and development of immune-related diseases and its potential as a target for immunotherapy.