1. Institute of Cell Biology and Immunology, University of Stuttgart, Allmandring 31, 70569 Stuttgart, Germany
2. These authors contributed equally to this work
3. National Institute for Medical Research, Division of Membrane Biology, The Ridgeway, Mill Hill, London NW7 1AA, UK
4. Institut für Gefäβbiologie und Thromboseforschung, University of Vienna, 1235 Vienna, Austria