First published online August 17, 2004
Journal of Cell Science 117, 1804e (2004)
© The Company of Biologists Limited
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Loading of antigenic peptides onto the MHC-II molecules that present them on the surface of antigen-presenting cells to T lymphocytes is thought to occur in endosomes. The peptides generally come from foreign proteins that enter the cell by endocytosis. However, many peptides purified from MHC-II molecules are derived from cytosolic self-proteins. To investigate how these peptides are loaded onto MHC-II molecules, a process that could be important in the regulation of immune self-tolerance, Satyajit Mayor, Satyajit Rath and co-workers have tracked a peptide-MHC-II complex (E
52-68-I-Ab) through several types of antigen-presenting cell (see p. 4219). The peptide was introduced into the cytosol of the cells by osmotic lysis of pinosomes, synthesized in the cytosole or naturally derived from the endogenous transmembrane protein. In all cases, the Ea52-68-I-Ab complex was detected first in a large perinuclear compartment containing lysosomal markers but not a late endosomal marker. Building on previous work, the authors conclude that the MHC-II pathway for presentation of endogenous and cytoplasmic proteins involves transport of peptides via lysosomes.
Related articles in JCS:
- The pathway for MHCII-mediated presentation of endogenous proteins involves peptide transport to the endo-lysosomal compartment
- Aadish Dani, Ashutosh Chaudhry, Paushali Mukherjee, Deepa Rajagopal, Sumeena Bhatia, Anna George, Vineeta Bal, Satyajit Rath, and Satyajit Mayor
JCS 2004 117: 4219-4230.
[Abstract]
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