1. Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520
2. Department of Cell and Developmental Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
3. Department of Cell Biology, The Scripps Research Institute, La Jolla, CA 92037
4. Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037
5. The Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037