1. From the Wellcome Trust Centre for Cell-Matrix Research (G.C., A.W., R.P.B.-H., A.E.C.), School of Biological Sciences, and the Cardiovascular Research Group (G.C., M.Y.A., V.O., J.O., A.E.C.), School of Medicine, University of Manchester, Manchester, UK; the Department of Pharmacology (B.C.V.), Amgen Inc, Thousand Oaks, Calif; and the Department of Genetics and Developmental Biology (Y.-W.F.), University of Connecticut Health Center, Farmington, Conn.