RPTOR and obesity due to melanocortin 4 receptor deficiency: Remarkably, acute increase in free Raptor levels reduced liver triglyceride and liver weight in both aged (Fig. 2c and Supplementary Fig. 2c) and DIO mice (Fig. 2d and Supplementary Fig. 2d), proving that the observed free Raptor deficit in these states has biological consequence, as replacement can ameliorate aging/obesity-induced hepatic steatosis.