PSMB8
PSMB8 (proteasome 20S subunit beta 8, also known as LMP7, beta5i, PSMB5i and RING10) is a catalytic beta subunit of the immunoproteasome. It takes part in antigen processing to generate peptides that bind MHC class I molecules. Browse Assay Genie's current range of PSMB8 research reagents below, or read on for the biology behind the target.
The proteasome is a multicatalytic proteinase complex that cleaves peptides with Arg, Phe, Tyr, Leu and Glu adjacent to the leaving group at neutral or slightly basic pH. PSMB8 is a subunit of the immunoproteasome, a modified proteasome whose essential function is the processing of class I MHC peptides. It replaces PSMB5 (catalytic subunit 3, beta 5), and this replacement increases the capacity of the immunoproteasome to cleave model peptides after hydrophobic and basic residues. PSMB8 also contributes to the generation of spliced peptides, formed by ligating two separate proteasomal cleavage products that are not contiguous in the parental protein.
The 20S core has a ring-shaped structure of four stacked rings: two rings of seven alpha subunits and two rings of seven beta subunits. The PSMB8 gene encodes a member of the proteasome B-type (T1B) family, and the protein is a 20S core beta subunit. Proteolytic processing is needed to generate the mature subunit. Two alternative transcripts encode two isoforms, and both are processed to the same mature subunit. In cancer cells, substitution of isoform 1 (E2) by isoform 2 (E1) results in immunoproteasome deficiency. The gene lies in the class II region of the MHC, and its expression is induced by gamma interferon. The PSMB8 protein is a major component of interferon gamma-induced sensitivity.
Beyond antigen processing, PSMB8 plays a key role in apoptosis through degradation of the apoptotic inhibitor MCL1. It may be involved in the inflammatory response pathway and is required for the differentiation of preadipocytes into adipocytes. Earlier names include large multifunctional peptidase 7 (LMP7) and proteasome (prosome, macropain) subunit, beta type, 8.
PSMB8 is involved in generating class I binding peptides, making it central to studies of MHC class I antigen presentation.
PSMB8 is a major component of interferon gamma-induced sensitivity, and its expression is induced by gamma interferon.
PSMB8 promotes apoptosis by degrading MCL1, and isoform switching in cancer cells results in immunoproteasome deficiency.
PSMB8 may be involved in the inflammatory response pathway and is required for preadipocyte differentiation into adipocytes.
PSMB8 is a catalytic beta subunit of the immunoproteasome. It helps generate peptides that bind MHC class I molecules, contributes to spliced peptide formation, and plays a role in apoptosis by degrading MCL1. It also replaces PSMB5 in the immunoproteasome.
PSMB8 is also called LMP7, beta5i, PSMB5i, RING10 and D6S216E. Earlier names include large multifunctional peptidase 7 and proteasome subunit beta 8. Two alternative transcripts encode two isoforms, and both are processed to the same mature subunit.
Orthologues exist in mouse and rat, both named Psmb8. In humans, the gene sits in the MHC class II region and is induced by gamma interferon. Check the datasheet of any product for its validated reactivity.
Other proteasome beta subunits and immunoproteasome components that work alongside PSMB8.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P28062; product specifications from Assay Genie datasheets.