MAP2K6 and obesity due to melanocortin 4 receptor deficiency: To test whether depletion of MKK6 has potential as a treatment for obesity, we fed a HFD to WT mice for 8 weeks and then injected them i.v. with lentivirus expressing a scrambled sequence or a shRNA targeting MKK6 (Fig. 6a) that we had already known that reduced MKK6 in adipose tissue (Supplementary Fig. 4a).