MAPK3 and Insulin resistance: We previously demonstrated that deletion of CL synthase (CLS) (Fig. 2A) driven by adiponectin-Cre, tamoxifen-inducible Rosa26-Cre, and tamoxifen-inducible UCP1-Cre (UCP1 Cre-ERT2) impairs thermogenesis and leads to insulin resistance (15).