1. CNRS UPR3082, Laboratoire d'Enzymologie et Biochimie Structurales, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France
2. N.N. Blokhin Cancer Research Center of Russian Federation, Kashirskoe shosse, 24, 115478 Moscow, Russia
3. Institut Curie, Centre de Recherche, 26 rue d'Ulm, 75248 Paris Cedex 05, France
4. CNRS UMR144, 26 rue d'Ulm, 75248 Paris Cedex 05, France
5. Institut Pasteur, Membrane traffic and cell division laboratory and CNRS URA 2582, 25-28 rue du Dr Roux, 75724 Paris Cedex 15, France
6. MRC Laboratory for Molecular Cell Biology and Department of Cell and Developmental Biology, University College London, Gower St, London, WC1E 6BT, UK