Molecular mechanisms for customizing peptides presented by MHC class I molecules

The end result of the antigen processing pathway is the display of peptide-bound MHC I molecules (pMHCI). The pMHC I are expressed on the cell surface where they can be surveyed by CD8 T cells for abnormal proteins. MHC I molecules present a large repertoire of peptides that fit perfectly in their binding grooves and represent the otherwise hidden intracellular contents. Here we will describe the findings from our laboratory that show how the antigen processing pathway generates and protects the proteolytic intermediates until they yield the final peptides that can fit the MHC I in the endoplasmic reticulum.