Characterizing the specificity and cooperation of aminopeptidases in the cytosol and endoplasmic reticulum during MHC class I antigen presentation.

ABSTRACT: Many MHC class I-binding peptides are generated as N-extended precursors during protein degradation by the proteasome. These peptides can subsequently be trimmed by aminopeptidases in the cytosol and/or the endoplasmic reticulum (ER) to produce mature epitope. However, the contribution and specificity of each of these subcellular compartments in removing N-terminal amino acids for Ag presentation is not well defined. In this study, we investigated this issue for antigenic precursors that are expressed in the cytosol. By systematically varying the N-terminal flanking sequences of peptides, we show that the amino acids upstream of an epitope precursor are a major determinant of the amount of Ag presentation. In many cases, MHC class I-binding peptides are produced through sequential trimming

SUBMITTER: Hearn A 

PROVIDER: S-EPMC2858786 | biostudies-literature | 2010 May

REPOSITORIES: biostudies-literature