Priming for destruction: septins at the crossroads of mitochondrial fission and bacterial autophagy

Mitochondria are essential organelles for cell survival, programmed cell death, and autophagy. They undergo cycles of fission and fusion, which are subverted by infectious pathogens and altered in many human diseases. Mitochondrial fission is mediated by the dynamin‐related protein Drp1, but the precise mechanism of its action is not well understood. In the last and current issues of EMBO Reports , two new studies [1], [2] reveal that the filamentous septin GTPases interact directly with Drp1, promoting mitochondrial fission. Moreover, mitochondria were found to promote the assembly of septin filaments into cages around cytosolic Shigella flexneri bacteria [2], which are targeted for autophagy. Thus, septins emerge as integral components of the machinery of mitochondrial fission and may pose a novel link between mitochondria and autophagy.