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Overlapping Peptide Library to Map Qa-1 Epitopes in a Protein
Published on: December 20, 2017
The ER aminopeptidase ERAP1 enhances or limits antigen presentation by trimming epitopes to 8-9 residues
Ian A York1, Shih-Chung Chang, Tomo Saric
1Department of Pathology, University of Massachusetts Medical Center, Worcester, MA 01655, USA. Ian.York@umassmed.edu
Abstract:
Endoplasmic reticulum (ER) aminopeptidase 1 (ERAP1) appears to be specialized to produce peptides presented on class I major histocompatibility complex molecules. We found that purified ERAP1 trimmed peptides that were ten residues or longer, but spared eight-residue peptides. In vivo, ERAP1 enhanced production of an eight-residue ovalbumin epitope from precursors extended on the NH2 terminus that were generated either in the ER or cytosol. Purified ERAP1 also trimmed nearly half the nine-residue peptides tested. By destroying such nine-residue peptides in normal human cells, ERAP1 reduced the overall supply of antigenic peptides. However, after interferon-gamma treatment, which causes proteasomes to produce more NH2-extended antigenic precursors, ERAP1 increased the supply of peptides for MHC class I antigen presentation.
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