MAPK8 and Insulin resistance: Activation of JNK has been established as a stress-mediated inducer of insulin resistance in diabetic animal models via phosphorylation of IRS-1 at Ser-307, leading to inactivation of IRS-1 by interfering with the interaction of the insulin receptor and IRS-1 and promoting IRS-1 degradation (Mamay et al, 2003).