Arif et al. discovered that glutamyl-prolyl-tRNA synthetase (EPRS) was a downstream effector of the mTORC1 and p70 ribosomal protein S6 kinase 1 (S6K1) axis, which was involved in the biological processes of obesity and aging63 (Fig. 3b). This evidence concerns the gene EPRS1 and obesity due to melanocortin 4 receptor deficiency.