STK11 and obesity due to melanocortin 4 receptor deficiency: PUN also suppresses various signaling pathways, including NF-kB, MAPK, Bcl-XL and LKB1-AMPK-p27, suggesting that PUN could have potential for therapeutics of various immune diseases, including cancer, atherosclerosis, hyperlipidemia, myocardial ischemia, diabetes, inflammation and infections, male infertility, brain damage, obesity and Alzheimer’s disease (Figure 1).