Consistent with our results, recent studies indicate that mTOR signaling is important not only for glucose and lipid metabolism25 but also for the regulation of gut barrier function26 and immune homeostasis via its effects on immune cell profiles27 and cytokine production28, both of which may play an essential role in controlling gut microbiota and affect the pathogenesis of obesity and diabetes. Here, MTOR is linked to obesity due to melanocortin 4 receptor deficiency.