1. From the Department of Medicine (F.S., Y.C., X.L., A.E.S., Y.G., N.D.D., T.Y., Y.L., K.U.K., K.L.P., J.C.), University of California-San Diego, La Jolla, Calif, and Institute of Cell Biology (A.H., J.-C.P.), ETH, Swiss Federal Institute of Technology, Zurich, Switzerland.