MAPK8 and obesity due to melanocortin 4 receptor deficiency: Many of these inflammatory proteins work to activate serine kinases, such as JNK, which directly blocks insulin action in muscle, liver and adipose tissue (Solinas & Becattini, 2016); conversely, selective inhibition of JNK in adipose tissue has been demonstrated to protect against diet‐induced obesity, improving insulin sensitivity in rodent liver and skeletal muscle (Zhang et al., 2011).