MAPK8 and obesity due to melanocortin 4 receptor deficiency: Based on the inverse correlation between the levels of DNAJB3 and activated JNK (Fig. 3B and 3C) and given the importance of stress kinases such as JNK, IKKβ in obesity and insulin resistance, we initially sought to determine if there is an interaction between DNAJB3 and these stress kinases.