1. Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158, United States
2. Small Molecule Discovery Center, University of California, San Francisco, California 94158, United States
3. Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109-1085, United States
4. Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, United States
5. Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115 United States