PKD2 and obesity due to melanocortin 4 receptor deficiency: In order to investigate the mechanisms underlying the amelioration of obesity in mice deficient for PKD2 activity, we used integrated analyses of metabolic parameters which revealed that inactivation of PKD2 does not affect food intake, energy expenditure, or voluntary movements of mice fed HFD (Figs 1K and L, and EV1I), suggesting that reduced body weight gain of Pkd2ki/ki upon HFD feeding must be caused by misregulation of other processes.