TRAF2 and obesity due to melanocortin 4 receptor deficiency: Mice that are deficient in CD40-TRAF2/3/5 signaling in MHCII+ cells display a similar phenotype as CD40−/− mice under HFD, whereas mice with disrupted CD40-TRAF6 signaling in MHCII+ cells are protected against obesity-induced metabolic dysfunction (27).