IARS1 and Insulin resistance: Insulin resistance implies changes upon insulin signaling, mainly in a transphosphorylation reaction that activates the insulin receptor substrate (IRS), an intrinsic kinase that activates the phosphatidylinositol 3-kinase- (PI3K-) AKT/protein kinase B (PKB) pathway to modulate most metabolic functions of insulin, such as glucose transport by GLUT-4 in adipocytes and myocytes.