This episode features Dr. McWilliam, who discusses the intricate microbial immune-detection system in mammals revolving around MR1, a highly conserved protein. MR1 plays a crucial role in capturing vitamin B-related metabolite antigens from various microbes and displaying them at the cell surface to stimulate MR1-restricted lymphocytes, including mucosal-associated invariant T (MAIT) cells.

This process of MR1 presentation and MAIT cell recognition aids in maintaining homeostasis through host defense and tissue repair mechanisms. However, the cellular mechanisms that regulate MR1 cell surface expression, which are critical for its function and MAIT cell recognition, remain largely unexplored.

Dr. McWilliam and his team report that human MR1 is equipped with a tyrosine-based motif in its cytoplasmic domain that facilitates low-affinity ...