TNF receptor‐associated factor 1 (TRAF1) expressed by hepatocytes has recently shown to play an important role in regulating obesity, insulin resistance and hepatic lipid accumulation, which is largely dependent on enhancing the activation of ASK1‐mediated JNK1‐IRS1‐Akt cascades.12 This evidence concerns the gene MAPK8 and obesity due to melanocortin 4 receptor deficiency.