Proteasome subtypes and the processing of tumor antigens: increasing antigenic diversity.
Protein degradation by the proteasome releases peptides that can be loaded on MHC class I molecules and presented to cytolytic T lymphocytes. Several mechanisms were recently found to increase the diversity of antigenic peptides displayed at the cell surface, thereby maximizing the efficacy of immune responses. The proteasome was shown to produce spliced antigenic peptides, which are made of two fragments initially not contiguous in the parental protein. Different proteasome subtypes also produce distinct sets of antigenic peptides: the standard proteasome and the immunoproteasome, containing different catalytic subunits, have different cleavage specificities and produce different sets of peptides. Moreover, recent work confirmed the existence of two additional proteasome subtypes that are intermediate between the standard and the immunoproteasome, and each produce a unique peptide repertoire.
Ludwig Institute for Cancer Research, Brussels Branch and de Duve Institute, Université catholique de Louvain, Brussels, Belgium.
Nathalie
N
Vigneron
Benoît J
BJ
Van den Eynde
D000818:Animals; D017951:Antigen Presentation; D000940:Antigenic Variation / Q000276:immunology*; D000951:Antigens, Neoplasm / Q000276:immunology*; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D006801:Humans; D007527:Isoenzymes / Q000145:classification; D009363:Neoplasm Proteins / Q000276:immunology*; D046988:Proteasome Endopeptidase Complex / Q000145:classification*; D011499:Protein Processing, Post-Translational
D000951:Antigens, Neoplasm; D015395:Histocompatibility Antigens Class I; D007527:Isoenzymes; D009363:Neoplasm Proteins; D046988:Proteasome Endopeptidase Complex