Every cell is enclosed by a thin double layer of lipids that separates the distinct internal environment of the cell from the extracellular space. Damage to this lipid bilayer, also referred to as plasma membrane, disturbs the cellular functions and may lead to the death of the cell. For example, downhill walking tears many little holes into the plasma membranes of the muscle cells in our legs. To prevent irreparable damage, muscle cells have efficient systems to seal these holes again. Researchers at Karlsruhe Institute of Technology (KIT) and Heidelberg University have succeeded for the first time in observing membrane repair in real-time in a living organism.