In the pathway of elevation of cytosolic Ca2 + levels and platelet calcium homeostasis, a recent study indicated that inflammation, either induced by cytokine exposure in vitro or by obesity in vivo, led to increased expression and activity of IP3Rs in adipocytes in a JNK-dependent manner and then increased cytosolic Ca2 + and impaired insulin action [18]. Here, MAPK8 is linked to obesity due to melanocortin 4 receptor deficiency.