1. Department of Cell Biology and The CBR Institute for Biomedical Research, Harvard Medical School Boston Massachusetts 02115 USA
2. Department of Physiology of Animals and Developmental Biology, Charles University Prague 2 Czech Republic
3. Institute of Chemistry and Cell Biology, ICCB, Harvard Medical School Boston Massachusetts 02115 USA
4. Department of Cellular Biology and Anatomy and Institute of Molecular Medicine and Genetics, Medical College of Georgia Augusta Georgia 30912 USA
5. Department of Neuroscience, DIBIT, Vita‐Salute San Raffaele University and San Raffaele Institute Via Olgettina 58 20132 Milano Italy
6. Department of Cell Biology, University Medical Centre and Institute for Biomembranes Heidelberglaan 100 3584 Utrecht The Netherlands