Structures of Class II MHC Molecules and Accessory Proteins During Trafficking in Subcellular Compartments
Synthetic rates of class II major histocompatibility complex (MHC) and associated molecules increased appreciably after 4 to 8 hours of polyclonal activation without any perceptible change in forms of those molecules. Ii was cleaved in intracellular vesicles to release a COOH-terminal p25 fragment at 20 to 40 minutes after [35S] methionine labeling. The association of Ii to class II MHC antigen could protect the desetope of class II MHC molecules from ambient peptides until reaching a foreign peptide containing endosome, there catalyzing the charging of digested foreign peptides onto the desetope in a concerted mechanism of Ii release and association of the foreign peptide. Ii could also retain class II MHC antigens in an endosome until charged for transport to the cell surface.
KeywordsPolyclonal Activation Foreign Peptide Percoll Density Gradient Centrifuga Imperial Cancer Research Fund Methionine Label
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