Cell biology: Double agents for mitochondrial division.

Abstract

Mitochondrial organelles — the energy powerhouses of the cell — must divide and fuse dynamically to function. It emerges that two distinct dynamin enzymes enable mitochondrial division. See Letter p.139 Mitochondria—the cellular organelles responsible for respiration and energy production—are dynamic systems that continuously undergo fission and fusion. It has been assumed that mitochondrial division, which involves remodelling of the mitochondrial membranes and constriction from about 500 nanometres down to 10 nanometres, is performed entirely by Drp1 (mitochondrial dynamin-related protein 1). Gia Voeltz and colleagues now report that, in addition to Drp1, mammalian cells use the classical dynamin-2 (Dyn2) to further constrict and divide mitochondria. In a sequential process, just prior to division Dyn2 seems to localize to mitochondrial constriction sites that have already been remodelled by Drp1.