ECs can regulate systemic energy allocation through MYCT1–IFITM2/3-mTORC1. (A) Delivery of nutrients to adipose tissue requires trafficking through ECs (arrow). (B) Nutrients are endocytosed by ECs in a regulated fashion, controlled by MYCT1. Once endocytosed, MYCT1 vesicles fused with early endosomes and lysosomes, promoting activation of mTORC1. Modified nutrients are released to tissues in the abluminal side of the EC. However, levels of MYCT1 control the type of endolysosomal trafficking, resulting in more or less transfer of nutrients to adipose tissue. (C) MYCT1 levels in the endothelium functions as a metabolic rheostat by controlling levels of mTORC1. Figure generated in BioRender.