1. Department of Neuroscience, Max‐Delbrück Center for Molecular Medicine, D 13125 Berlin, Germany
2. Electron Microscopy Core Facility, Max‐Delbrück Center for Molecular Medicine, D 13125 Berlin, Germany
3. Department of Cancer Research, Max‐Delbrück Center for Molecular Medicine, D 13125 Berlin, Germany
4. Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois 60612
5. Department of Zoology and Entomology, Mammal Research Institute, University of Pretoria, 5100 Pretoria, South Africa