1. European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
2. Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK.
3. Department of Systemic Cell Biology, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany.
4. Samuel Lunenfeld Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario, Canada M5G 1X5.
5. Technische Universität Dortmund, Fachbereich Chemie, 44227 Dortmund, Germany.