1. Department of Molecular Biology, Universitätsmedizin Göttingen, Humboldtallee 23, Göttingen 37073, Germany
2. Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Hermann-Rein Str. 3, Göttingen 37075, Germany
3. MPI-EM Light Microscopy Facility, Max Planck Institute of Experimental Medicine, Hermann-Rein Str. 3, Göttingen 37075, Germany