MAPK1 and cardiac hypertrophy: No hypertrophy was observed in any of these mice compared to wild-type mice at baseline, suggesting that over-expression of wildtype ERK does not lead to hypertrophy, that the phosphorylation on Thr188 on ERK2 is not sufficient to induce cardiac hypertrophy, or that the Erk2T188D mutant dose not mimic the endogenous phosphorylation on Thr188.