The same phosphopeptide was similarly regulated infibroblasts by ECM stiffness and in hypercontractile hearts of patients withhypertrophic cardiomyopathy (Fig. 7b).Using immunoblotting, we observed an electrophoretic mobility shift of wild-type(WT) MIEF1 upon ROCK–MCLK inhibition and a similar shift was observedwith a mutated variant of MIEF1 precluding phosphorylation (S55/59A; SA variant)(Fig. 7c), consistent with reducedphosphorylation. The gene discussed is MIEF1; the disease is cardiomyopathy.