AKT1 and obesity due to melanocortin 4 receptor deficiency: Importantly, PI3K-Akt pathway, which plays an essential role in cellular physiology by regulating growth factor signals during organismal growth and critical cellular processes (e.g., lipid metabolism, glucose homeostasis, protein synthesis, cell proliferation and survival) in normal physiology and morbid conditions (e.g., obesity and T2D) [48].