MAPK8 and cardiac hypertrophy: To further illuminate whether the activation of TAK1–JNK1/2/p38 signalling is required for TRAF6-mediated cardiac hypertrophy, we co-transfected NRCMs with AdTraf6 and AddnTak1, which carries a dominant-negative Tak1 mutant, or co-transfected NRCMs with AdshTraf6 and AdcaTak1, which carries a constitutively activating Tak1 mutant.