An antigenic peptide produced by reverse splicing and double asparagine deamidation.

Abstract

A variety of unconventional translational and posttranslational mechanisms contribute to the production of antigenic peptides, thereby increasing the diversity of the peptide repertoire presented by MHC class I molecules. Here, we describe a class I-restricted peptide that combines several posttranslational modifications. It is derived from tyrosinase and recognized by tumor-infiltrating lymphocytes isolated from a melanoma patient. This unusual antigenic peptide is made of two noncontiguous tyrosinase fragments that are spliced together in the reverse order. In addition, it contains two aspartate residues that replace the asparagines encoded in the tyrosinase sequence. We confirmed that this peptide is naturally presented at the surface of melanoma cells, and we showed that its processing sequentially requires translation of tyrosinase into the endoplasmic reticulum and its retrotranslocation into the cytosol, where deglycosylation of the two asparagines by peptide-N-glycanase turns them into aspartates by deamidation. This process is followed by cleavage and splicing of the appropriate fragments by the standard proteasome and additional transport of the resulting peptide into the endoplasmic reticulum through the transporter associated with antigen processing (TAP).

• Authors: Alexandre Dalet, Paul F Robbins, Vincent Stroobant, Nathalie Vigneron, Yong F Li, Mona El-Gamil, Ken-ichi Hanada, James C Yang, Steven A Rosenberg, Benoît J Van den Eynde
• Journal: Proceedings of the National Academy of Sciences of the United States of America (Proc Natl Acad Sci U S A) Vol. 108 Issue 29 Pg. E323-31 (Jul 19 2011) ISSN: 1091-6490 [Electronic] United States
• PMID: 21670269 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antibodies, Monoclonal
• Histocompatibility Antigens Class I
• Peptides
• Monophenol Monooxygenase

Topics

• Antibodies, Monoclonal
• Antigen Presentation (immunology)
• Chemical Fractionation
• Chromatography, High Pressure Liquid
• Endoplasmic Reticulum (metabolism)
• Histocompatibility Antigens Class I (immunology, metabolism)
• Humans
• Lymphocytes, Tumor-Infiltrating (metabolism)
• Melanoma (immunology, metabolism)
• Monophenol Monooxygenase (genetics)
• Peptides (genetics, immunology, isolation & purification, metabolism)
• Protein Processing, Post-Translational (genetics, immunology)
• Protein Transport (immunology)