MAPK8 and Insulin resistance: In order to unravel the mechanism by which the insulin resistance occurs in the TLR2 KO mice, we studied important pathways involved in this phenomenon: phosphorylation of JNK, activation of ER stress, serine phosphorylation of the insulin receptor substrate (IRS)-1, and expression of IκB-α, which is involved in the inhibition of the IKK/NFκB pathway activation.