1. Inserm U770, Hôpital Bicêtre, Le Kremlin-Bicêtre, France;
2. Université Paris VII Denis Diderot, Paris, France;
3. IFR4, Laboratoire d'Hématologie, Hôpital Cardiologique, Pessac, France;
4. Institut des Vaisseaux et du Sang, Paris, France;
5. Center for Molecular and Vascular Biology, University of Leuven, Leuven, Belgium; and
6. Howard Hughes Medical Institute and Program in Molecular Medicine, Department of Biochemistry and Molecular Biology, University of Massachusetts Medical School, Worcester