1. Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Chemin des Boveresses 155, CH 1066 Epalinges, Switzerland.
2. Cell Microscopy Center and Department of Cell Biology, University Medical Centre Utrecht, Heidelberglaan 100, 3584CX Utrecht, the Netherlands.
3. Institute of Genetics and Biophysics “A. Buzzati-Traverso,” Via P. Castellino 111, 80131 Naples, Italy.