1. Department of Cancer Biology
2. Department of Neuroscience, Max-Delbrück-Center for Molecular Medicine, 13125 Berlin, Germany
3. Department of Cell Biology, Helmholtz Centre for Infection Research, D-38124 Braunschweig, Germany
4. Institute of Physiology, Charité-Medical University Berlin, 14195 Berlin, Germany
5. Institute of Cell Biology, ETH Zürich, Hönggerberg, CH-8093 Zürich, Switzerland