Gone fission…: diverse consequences of cardiac Drp1 deficiency.

Mitochondrial fission and fusion proteins are highly expressed in myocardium. However, mitochondrial fission and fusion are rare, and mitochondrial networks are absent, in adult cardiomyocytes, obviating a need for morphometric mitochondrial remodeling. The critical role of mitochondrial dynamics factors in hearts therefore remains to be determined. In this issue of Ikeda et al describe a central function for the mitochondrial fission protein, Dynamin-related protein 1 (Drp-1), in macroautophagy and mitochondrial autophagy. Together with two other recent reports that cardiac-specific deletion of Drp1 perturbs mitophagy, these findings point to modulation of targeted mitochondrial elimination as a major quality control function for Drp1, and possible other mitochondrial dynamism factors, in the heart.