1. Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois 60153, United States
2. Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, United States
3. Department of Chemistry & Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37235, United States
4. Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
5. Department of Biochemistry and Molecular Biology, Life Sciences Centre, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada