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Presentation of Cytosolic Glycosylated Peptides by Human Class I Major Histocompatibility Complex Molecules in Vivo

Authors :
Haurum, John S.
Høier, Ingelise Bjerring
Arsequell, Gemma
Neisig, Anne
Valencia, Gregorio
Zeuthen, Jesper
Neefjes, Jacques
Elliott, Tim
Source :
The Journal of Experimental Medicine; July 1999, Vol. 190 Issue: 1 p145-150, 6p
Publication Year :
1999

Abstract

Antigens presented by class I major histocompatibility complex (MHC) molecules for recognition by cytotoxic T lymphocytes consist of 8–10-amino-acid-long cytosolic peptides. It is not known whether posttranslationally modified peptides are also presented by class I MHC molecules in vivo. Many different posttranslational modifications occur on cytoplasmic proteins, including a cytosolic O-β-linked glycosylation of serine and threonine residues with N-acetylglucosamine (GlcNAc). Using synthetic glycopeptides carrying the monosaccharide O-β-GlcNAc substitution on serine residues, we have shown that glycopeptides bind efficiently to class I MHC molecules and elicit a glycopeptide-specific cytotoxic T lymphocyte response in mice. In this study, we provide evidence that peptides presented by human class I MHC molecules in vivo encompass a small, significant amount of glycopeptides, constituting up to 0.1% of total peptide. Furthermore, we find that carbohydrate structures present on glycopeptides isolated from class I MHC molecules are dominated by the cytosolic O-β-GlcNAc substitution, and synthetic peptides carrying this substitution are efficiently transported by TAP (transporter associated with antigen presentation) into the endoplasmic reticulum. Thus, in addition to unmodified peptides, posttranslationally modified cytosolic peptides carrying O-β-linked GlcNAc can be presented by class I MHC molecules to the immune system.

Details

Language :
English
ISSN :
00221007 and 15409538
Volume :
190
Issue :
1
Database :
Supplemental Index
Journal :
The Journal of Experimental Medicine
Publication Type :
Periodical
Accession number :
ejs57368067
Full Text :
https://doi.org/10.1084/jem.190.1.145