1. Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany.
2. Biozentrum, University of Basel, Klingelbergstrasse 50/70, CH-4056 Basel, Switzerland.
3. Trypanosome Cell Biology Unit, Institut Pasteur and CNRS URA2581, 25 Rue du Docteur Roux, 75015 Paris, France.
4. Department of Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany.