1. Endothelial Cell Biology Unit, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, U.K.
2. Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, U.K.
3. Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, U.K.
4. National Cardiovascular Center Research Institute, Osaka 565-565, Japan