1. Department of Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093, USA.
2. School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, USA.
3. Department of Chemistry and Biochemistry, University of California, San Diego, School of Medicine, La Jolla, CA 92093, USA.
4. Department of Cellular and Molecular Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093, USA.