We evaluated the effect of MKL1 deletion in resident fibroblasts on cardiac fibrosis in a classic model in which the left anterior descending artery was permanently ligated to induce myocardial infarction (MI, Figure 2A); significant cardiac fibrosis typically develops within 7 days of the surgical procedure (Cleutjens et al., 1995). Here, MRTFA is linked to myocardial infarction.