IARS1 and Insulin resistance: A number of signaling molecules, such as IκB kinase (IKK) [31], mammalian target of rapamycin (mTOR) [32], PKCζ [33], S6 Kinase 1 (S6K1) [34], ERK [35] and JNK [36], [37] have been shown to function as IRS serine kinases that induce insulin resistance by promoting the inhibitory phosphorylation of IRS (reviewed in [26], [38]).