ARC and obesity due to melanocortin 4 receptor deficiency: In response to a high-fat diet, the absence of JNK3 signal in Arc NPY neurons will increase the electrical excitability of neurons, which increases food intake and causes obesity, suggesting that the Arc NPY neuron JNK3 signaling pathway plays an important role in maintaining metabolic homeostasis under conditions of metabolic stress such as that of a high-fat diet (Vernia et al., 2016).