Raw data for all experiments.

MR1 is a ubiquitously expressed MHC-Ib molecule that presents microbial metabolites to MR1-restricted T cells, but there are differences in the antigen presentation pathway of an intracellular microbe compared to exogenously delivered antigen. We have shown the importance of endosomal trafficking proteins in MR1-dependent presentation of Mycobacterium tuberculosis (Mtb) infection. Two pore channels (TPCs) are endosomal calcium channels that regulate endosomal trafficking. Due to their location on endosomes, we hypothesized that TPCs could be required for MR1-dependent presentation of antigens derived from the intracellular microbe Mtb. We found that TPC1 is critical for the presentation of Mtb infection by MR1; inhibition of TPCs had no effect on MR1 presentation of exogenously delivered antigens, HLA-B presentation, or HLA-II presentation. Finally, we found that the calcium-sensitive trafficking protein Synaptotagmin 7 was also key in the presentation of Mtb infection by MR1. TPC1 and Synaptotagmin 7 may be part of an endosomal pathway by which MR1 can sample intracellular mycobacterial infections.MR1是一种广泛表达的主要组织相容性复合体I类Ib（Major Histocompatibility Complex class Ib, MHC-Ib）分子，可将微生物代谢物呈递给MR1限制性T细胞，但胞内微生物的抗原呈递通路与外源性递送抗原的呈递通路存在差异。我们已证实内体转运蛋白在结核分枝杆菌（Mycobacterium tuberculosis, Mtb）感染的MR1依赖性抗原呈递过程中具有重要作用。双孔通道（Two Pore Channels, TPCs）是一类调控内体转运的内体钙通道，鉴于其定位于内体，我们推测TPCs可能是胞内微生物结核分枝杆菌来源抗原的MR1依赖性呈递所必需的因子。我们发现TPC1对于MR1呈递结核分枝杆菌感染至关重要；抑制TPCs对MR1呈递外源性递送抗原、人类白细胞抗原B（HLA-B）呈递以及人类白细胞抗原II类（HLA-II）呈递均无显著影响。此外，我们还发现钙敏感转运蛋白突触结合蛋白7（Synaptotagmin 7）同样是MR1呈递结核分枝杆菌感染的关键因子。TPC1与突触结合蛋白7可能参与构成了MR1获取胞内分枝杆菌感染相关抗原的内体通路。