For life to function, cell membranes must remain intact. When these fragile barriers are damaged—for instance by heat or viral attack—specialized proteins come to the rescue. Researchers at Forschungszentrum Jülich, Heinrich Heine University Düsseldorf and the University of Mainz have now, for the first time, uncovered the mechanism of action of one such protective protein, PspA, which belongs to the ESCRT-III superfamily.