1. From the Department of Physiology and Pennsylvania Muscle Institute, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania; the2Department of Anatomy and Clinical Morphology, University of Witten/Herdecke School of Medicine, Witten, Ge
2. From the Department of Physiology and Pennsylvania Muscle Institute, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania; the
3. Institute of Cell Biology, Swiss Federal Institute of Technology, ETH-Honggerberg, Zurich, Switzerland; and the4Cardiovascular Division of Surgical Research, University Hospital, Zurich, Switzerland.
4. Institute of Cell Biology, Swiss Federal Institute of Technology, ETH-Honggerberg, Zurich, Switzerland; and the