Allelic variation alters expression and antigen presentation of MR1 allomorphs

AG Nelson; V Letoga; CZQ Lee; C Samer; S Li; LJ Meehan; HEG McWilliam; NA Gherardin; A Abendroth; JA Villadangos; B Slobedman; AJ Corbett; J McCluskey; J Rossjohn; Z Chen; MNT Souter; W Awad

Journal article

Allelic variation alters expression and antigen presentation of MR1 allomorphs

AG Nelson, V Letoga, CZQ Lee, C Samer, S Li, LJ Meehan, HEG McWilliam, NA Gherardin, A Abendroth, JA Villadangos, B Slobedman, AJ Corbett, J McCluskey, J Rossjohn, Z Chen, MNT Souter, W Awad

Journal of Biological Chemistry | Elsevier BV | Published : 2026

DOI: 10.1016/j.jbc.2026.111470

Open access

Abstract

The major histocompatibility complex (MHC) class I-related protein 1 (MR1) presents vitamin B-derived metabolites to mucosal-associated invariant T (MAIT) and other T cells. There is limited polymorphism of MR1, the functional impact of which is not understood. We examined the impact of allelic variation of MR1 on the expression, structure and function of the known MR1 allomorphs. The expression and function of MR1∗02, MR1∗03, and MR1∗06 were similar to the canonical MR1∗01. Crystal structures of four MR1 allomorphs show that their polymorphisms do not impact the three-dimensional fold of MR1. Despite the binding of 5-OP-RU to MR1∗05 and its cell surface upregulation, this allomorph was seve..

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