MAPK3 and chronic kidney disease: In our current study, left ventricular total ERK1 and ERK2 levels, phospho-ERK1 and phospho-ERK2 levels, phospho-ERK1/total ERK1 ratio, phospho-ERK2/total ERK2 ratio, total AMPK level, phospho-AMPK level, and phospho-AMPK/total AMPK ratio failed to change significantly in CKD as compared to the sham group (Fig. 7).