RUNX1 and myocardial infarction: Our previous results at the later time point of 2 weeks post-MI demonstrated a role for Runx1 in determining SERCA-mediated calcium uptake, SR calcium content, and calcium transient amplitude.21 The current study provides new insight in that this function of RUNX1 is evident in BZ cardiomyocytes as early as 1-day post-MI.