PSMB8 Gene

The PSMB8 gene (PSMB8 stands for "Proteasome 20S Subunit Beta 8" also called LMP7 =low molecular mass protein 7 or beta5i) is a protein coding gene located on chromosome 6p21.32. The PSMB8 gene is located in the class II region of the MHC (Major Histocompatibility Complex). The PSMB8 gene encodes the beta8 subunit in a 20S proteasome (proteasomes expressing this subunit are called immunoproteasomes - see below.proteasome- ).

Two alternative transcripts encoding two isoforms have been identified for the PSMB8 gene; both isoforms are processed, and can generate the same mature subunit of the proteasome. Expression of the gene is induced by gamma interferon.

1. Agarwal AK et al (2010) PSMB8 encoding the beta-5i proteasome subunit is mutated in joint contractures, muscle atrophy, microcytic anemia, and panniculitis-induced lipodystrophy syndrome. Am J Hum Genet 87: 866-872.
2. Arima K et al (2011) Proteasome assembly defect due to a proteasome subunit beta type 8 (PSMB8) mutation causes the autoinflammatory disorder, Nakajo-Nishimura syndrome. Proc Nat Acad Sci 108: 14914-14919.
3. Brehm A et al (2015) Additive loss-of-function proteasome subunit mutations in CANDLE/PRAAS patients promote type I IFN production. J Clin Invest 125: 4196-4211.
4. Ebstein F et al (2019) Contribution of the unfolded protein response (UPR) to the pathogenesis of proteasome-associated autoinflammatory syndromes (PRAAS). Front Immune 10: 2756.
5. Garg A et al (2010) An autosomal recessive syndrome of joint contractures, muscular atrophy, microcytic anemia, and panniculitis-associated lipodystrophy. J Clin Endocr Metab 95: E58-63.
6. Kitamura A et al (2011) A mutation in the immunoproteasome subunit PSMB8 causes autoinflammation and lipodystrophy in humans. J Clin Invest 121: 4150-4160.