1. From the Department of Medical Biochemistry (G.M., S.H., A.v.B., A.F.G., N.B., A.A.J.H., C.J.M.d.V., V.d.W.), Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory (M.H., J.D.v.B.), and Department of Cell Biology and Histology (J.S.), Academic Medical Center, University of Amsterdam, The Netherlands.