MR1

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Description

The MR1 (major histocompatibility complex, class I-related) is a protein-coding gene located on chromosome 1.

MR1 or MR-1 may refer to:

MR1 is an antigen-presenting molecule that specializes in displaying microbial pyrimidine-based metabolites to alpha-beta T cell receptors (TCR) on innate-type mucosal-associated invariant T (MAIT) cells. In complex with B2M, MR1 preferentially presents riboflavin-derived metabolites to semi-invariant TRAV1-2 TCRs on MAIT cells, guiding immune surveillance of the microbial metabolome at mucosal epithelial barriers. Signature pyrimidine-based microbial antigens are generated via non-enzymatic condensation of metabolite intermediates of the riboflavin pathway with by-products arising from other metabolic pathways such as glycolysis. Typical potent antigenic metabolites are 5-(2-oxoethylideneamino)-6-D-ribitylaminouracil (5-OE-RU) and 5-(2- oxopropylideneamino)-6-D-ribitylaminouracil (5-OP-RU), products of condensation of 5-amino-6-D-ribitylaminouracil (5-A-RU) with glyoxal or methylglyoxal by-products, respectively. MR1 may present microbial antigens to various TRAV1-2-negative MAIT cell subsets, providing for unique recognition of diverse microbes, including pathogens that do not synthesize riboflavin. Upon antigen recognition, MR1 elicits rapid innate-type MAIT cell activation to eliminate pathogenic microbes by directly killing infected cells. During T cell development, MR1 drives thymic selection and post-thymic terminal differentiation of MAIT cells in a process dependent on commensal microflora. MR1 acts as an immune sensor of cancer cell metabolome. MR1 may present a tumor-specific or -associated metabolite essential for cancer cell survival to a pan-cancer TCR consisting of TRAV38.2-DV8TRAJ31 alpha chain paired with a TRBV25.1TRBJ2.3 beta chain on a non-MAIT CD8- positive T cell clone (MC.7.G5), triggering T cell-mediated killing of a wide range of cancer cell types.

MR1 is also known as HLALS.

Associated Diseases

• progressive supranuclear palsy
• C1 inhibitor deficiency
• immunodeficiency 28
• varicella, severe recurrent
• recurrent Neisseria infections due to factor D deficiency