1Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
2Department of Biomolecular Chemistry, University of Wisconsin, Madison, WI, USA
3Department of Genetics, Yale University, New Haven, CT, USA
4Physiological Chemistry Institute, University of Munich, Munich, Germany
5GSF Clinical Hematology Institute, Munich, Germany
6Department of Pharmacology, University of Nebraska Medical Center, Omaha, NE, USA
7Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA