Co-regulation and transactivation of CCAAT/enhancer-binding protein beta (C/EBPβ), Nuclear Factor-κB (NFκB) and activating protein-1 (AP-1) have been reported in the context of obesity, insulin resistance, and inflammation [16–19] as they are involved in the upregulation of inflammatory mediators [20, 21]. Here, JUN is linked to obesity due to melanocortin 4 receptor deficiency.