1. Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
2. Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA.
3. Department of Dermatology, University of California San Francisco, San Francisco, CA 94115, USA.
4. Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
5. Department of Biochemistry and Molecular Biology, University of Maryland Baltimore, Baltimore, MD 21201, USA.
6. Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
7. Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
8. Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.