DNM1L and heart failure: On the other hand, a DRP1 loss-of-function mutation (Ashrafian et al., 2010; Cahill et al., 2015) or cardiac specific inactivation of DRP1 (Kageyama et al., 2014; Ikeda et al., 2015; Ishihara et al., 2015; Song et al., 2015a,b) invariably leads to heart failure, underscoring an essential role of mitochondrial fission in maintaining cardiac homeostasis.