MAPK8 and familial dilated cardiomyopathy: Study of ERK, JNK, and p38 in the hearts of end-stage DCM patients demonstrated that the total ERK, JNK, and p38 levels did not vary from healthy hearts; however, activation of these kinases differed greatly, as ERK was upregulated, and activity of p38 decreased, while phosphorylation of JNK did not change in failing hearts [41].