RPTOR and obesity due to melanocortin 4 receptor deficiency: As AMPK-dependent phosphorylation of Raptor has earlier been shown to be required for the inhibition of mTORC1 in the event of energy stress, decreased phosphorylation with increasing BMI is in line with the reported increase of mTORC1 activity in obesity (Gwinn et al., 2008; Laplante and Sabatini, 2012).