Cells multiply by duplicating themselves: they grow, replicate their components, and finally split into two. Many diseases are related to defective cell division; cancer is one of them. Understanding mechanisms conducting this division is therefore essential in the search for cancer treatments. Researchers at the University of Geneva (UNIGE), Switzerland, in collaboration with the IMBA- Institute of Molecular Biotechnology at the Vienna BioCenter (VBC) and the Weill Cornell Medical College in New York, have turned their attention in particular to the role of ESCRT proteins, which are responsible for severing cell membranes. These proteins assemble in spirals that gradually bring about cleavage of the membrane, spirals that are constantly renewing themselves with the help of the Vps4 molecule. Without this molecule the renewal stops, eventually preventing the membrane from being severed. This research, reported in the journal Nature Cell Biology, sheds new light on the fight against cancer and HIV, both of which depend on cell division.