Projects per year
Abstract
The antigen-presenting molecule MR1 (MHC class I-related protein 1) presents metabolite antigens derived from microbial vitamin B2 synthesis to activate mucosal-associated invariant T (MAIT) cells. Key aspects of this evolutionarily conserved pathway remain uncharacterized, including where MR1 acquires ligands and what accessory proteins assist ligand binding. We answer these questions by using a fluorophore-labeled stable MR1 antigen analog, a conformation-specific MR1 mAb, proteomic analysis, and a genome-wide CRISPR/Cas9 library screen. We show that the endoplasmic reticulum (ER) contains a pool of two unliganded MR1 conformers stabilized via interactions with chaperones tapasin and tapasin-related protein. This pool is the primary source of MR1 molecules for the presentation of exogenous metabolite antigens to MAIT cells. Deletion of these chaperones reduces the ERresident MR1 pool and hampers antigen presentation and MAIT cell activation. The MR1 antigen-presentation pathway thus co-opts ER chaperones to fulfill its unique ability to present exogenous metabolite antigens captured within the ER.
Original language | English |
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Pages (from-to) | 24974-24985 |
Number of pages | 12 |
Journal | Proceedings of the National Academy of Sciences of the United States of America |
Volume | 117 |
Issue number | 40 |
DOIs | |
Publication status | Published - 6 Oct 2020 |
Keywords
- Fluorescent probe
- MAIT cells
- MHC class I-related protein 1 (MR1)
- Protein trafficking
- Vitamin B
Projects
- 1 Finished
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ARC Centre of Excellence in Advanced Molecular Imaging
Whisstock, J. (Primary Chief Investigator (PCI)), Abbey, B. (Chief Investigator (CI)), Nugent, K. A. (Chief Investigator (CI)), Quiney, H. M. (Chief Investigator (CI)), Godfrey, D. I. (Chief Investigator (CI)), Heath, W. (Chief Investigator (CI)), Fairlie, D. P. (Chief Investigator (CI)), Chapman, H. (Partner Investigator (PI)), Peele, A. (Partner Investigator (PI)), Davey, J. (Partner Investigator (PI)) & Wittmann, A. (Project Manager)
30/06/14 → 31/03/21
Project: Research