NPPA and heart failure: Analysis of stress markers related to heart failure in mice by western blot revealed that expression of cardiac stress marker atrial natriuretic protein (ANP) was significantly increased in MACF1 KO hearts as compared to WT hearts exposed to TAC (Figure 3G, H), while Serca2a protein, which is often reduced in heart failure, was significantly lower in MACF1 KO hearts after TAC than in WT hearts (Figure 3G, I).