CREB3L3 and obesity due to melanocortin 4 receptor deficiency: Given the preserved browning potential of the iWAT in response to cold (Supplemental Fig. 4) and the temperature-dependence of the obesity-promoting phenotype of the fKO mouse (Fig. 4i,j), it appears that altered brown fat metabolism is the main contributor to the obesigenic effect of adipose CREB3L3 ablation.