A recent study identified Kruppel-like zinc-finger family 10 in CD4+ T cells as an essential regulator of obesity, insulin resistance, and fatty liver, the effects of which are mediated by PI3K-AKT-mTOR signaling.121 Conversely, specific ablation of the insulin receptor in myeloid cells led to reduced obesity-associated inflammation in adipose tissue.122 These opposite results indicate the different roles of PI3K/AKT signaling in lymphoid and myeloid cells. The gene discussed is INSR; the disease is obesity due to melanocortin 4 receptor deficiency.