Proteasome assembly chaperone 2 （PSMG2） stimulates assembly of the 20S proteasome as part of a heterodimer with PSMG1. The PSMG1-PSMG2 heterodimer binds to the PSMA5 and PSMA7 proteasome subunits and promotes compilation of the proteasome alpha subunits into the heteroheptameric alpha ring and prevents alpha ring dimerization. PSMG2 is widely expressed with highest levels in the lung， brain and colon. It is moderately expressed in the muscle， stomach， spleen and heart， and weakly expressed in the small intestine， pancreas and liver. It is also highly expressed in hepatocellular carcinomas with low levels in surrounding liver tissue.
