Endosomal proteolysis and MHC class II function.
Newly synthesized MHC class II alpha and beta chains associate with a protein chaperone, the invariant chain, which promotes the proper assembly of MHC class II complexes and their trafficking through cells and prevents their untimely loading with peptides. Efficient loading of MHC class II heterodimers with antigenic peptides requires concurrent proteolytic processing of both the invariant chain and endocytosed proteins. Recent studies have elucidated the critical roles of specific cysteine proteases, especially cathepsins S and L, in degrading the invariant chain and regulating the convergence of processed antigen and MHC class II dimers competent for peptide loading.
Chapman
H A
HA
Department of Medicine, Brigham and Women's Hospital, Boston, MA, USA. hchapman@rics.bwh.harvard.edu
D000595:Amino Acid Sequence; D000818:Animals; D000938:Antigen-Presenting Cells / Q000378:metabolism; D010450:Endopeptidases / Q000378:metabolism*; D011992:Endosomes / Q000201:enzymology*; D020689:Exopeptidases; D015395:Histocompatibility Antigens Class I / Q000276:immunology; D000949:Histocompatibility Antigens Class II / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D010447:Peptide Hydrolases; D010455:Peptides / Q000276:immunology
D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D010455:Peptides; D010450:Endopeptidases; D020689:Exopeptidases; D010447:Peptide Hydrolases