1. Howard Hughes Medical Institute, Department of Pharmacology, and Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Box 357370, Seattle, WA 98195, USA.
2. Rosetta Inpharmatics, LLC, Merck & Co Inc., 401 Terry Avenue N, Seattle, WA 98109, USA.
3. Merck Research Labs, Department of Automated Biotechnology, North Wales, PA 19454, USA.
4. Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA 98195, USA.
5. Proteomics Resource, University of Washington, Seattle, WA 98109, USA.
6. Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada M5S 3M2.