1. Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan 48104, United States
2. Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109, United States
3. Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, Michigan 48109, United States
4. Rogel Cancer Center, University of Michigan, Ann Arbor, Michigan 48109, United States
5. Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, United States