MHC I-associated peptides preferentially derive from transcripts bearing miRNA response elements

Abstract

MHC I-associated peptides (MIPs) play an essential role in normal homeostasis and diverse pathologic conditions. MIPs derive mainly from defective ribosomal products (DRiPs), a subset of nascent proteins that fail to achieve a proper conformation and the physical nature of which remains elusive. In the present study, we used high-throughput proteomic and transcriptomic methods to unravel the structure and biogenesis of MIPs presented by HLA-A and HLA-B molecules on human EBV-infected B lymphocytes from 4 patients. We found that although HLA-different subjects present distinctive MIPs derived from different proteins, these MIPs originate from proteins that are functionally interconnected and implicated in similar biologic pathways. Secondly, the MIP repertoire of human B cells showed no bias toward conserved versus polymorphic genomic sequences, were derived preferentially from abundant transcripts, and conveyed to the cell surface a cell-type-specific signature. Finally, we discovered that MIPs derive preferentially from transcripts bearing miRNA response elements. Furthermore, whereas MIPs of HLA-disparate subjects are coded by different sets of transcripts, these transcripts are regulated by mostly similar miRNAs. Our data support an emerging model in which the generation of MIPs by a transcript depends on its abundance and DRiP rate, which is regulated to a large extent by miRNAs.,

Publication
Blood
Tariq Daouda
Tariq Daouda
Étudiant au doctorat en bio-informatique (2011-2018 avec Claude Perrault, IRIC)
Sébastien Lemieux
Sébastien Lemieux
Principal Investigator

Principal Investigator, Functional and Structural Bioinformatics Research Unit, IRIC | Scientific direction of the Bioinformatics platform | Associate Professor, Department of Biochemistry and Molecular Medicine, Université de Montréal