If you want to make a synthetic cell, you have to find a way to make it divide. Natural cells do this all the time. Nicola De Franceschi, Cees Dekker and colleagues at the Technical University of Delft have taken a step in this direction by studying how a bacterial protein, dynamin A (DynA), helps to induce half or full scission in dumbbell-shaped liposomes from the inside.

The researchers used a special method (synthetic membrane shaper) to make liposomes that are linearly attached to each other with a small open ‘neck’, which shapes the liposomes like a dumbbell. They labelled the lipids - which formed a double layer - with fluorescent compounds and monitored the processes using fluorescence microscopy and fluorescence recovery after photobleaching (FRAP). This showed that DynA accumulates in the membrane neck (inside the liposomes) and catalyses half or full division from there. This function was previously unknown.

DynA proteins appear to physically interact with the membrane neck to pull the walls of the neck together, leading initially to hemi-scission until the moment the liposomes separate and scission is complete. Dekker and colleagues see many advantages of this protein as a cell division machine (divisome). Other divisomes, such as the ESCRT-III complex, consist of several components that need to fit together correctly and are therefore more difficult to use than DynA, which consists of only one component. Another advantage of DynA is that it visualises this hemi-scission, which gives you a better idea of what these liposomes look like. In the ESCRT-III complex, this phase is probably too short to observe.

De Franceschi, N. et al. (2023) Nat. Nanotechnol., DOI: 10.1038/s41565-023-01510-3