STK26 and obesity due to melanocortin 4 receptor deficiency: To investigate the potential functional role of MST4 on the progression of diet-induced obesity, we challenged male mice with the whole-body depletion of MST4 and their wild-type littermates with a high-fat diet (45 kcal% fat) for 18 weeks, which mimics the environment in high-risk individuals (Figure 1A).