Mitochondrial double membrane fission: A mystery solved?

It has long been an unresolved question whether the division machineries that assemble on the mitochondrial surface cooperate with factors inside the organelle. Now, two studies by Connor et al. (2023. J. Cell Biol.https://doi.org/10.1083/jcb.202303147) and Fukuda et al. (2023. Mol. Cell.https://doi.org/10.1016/j.molcel.2023.04.022) have identified an intermembrane space protein that is crucial for mitochondrial double membrane division.