1. Metabolic Biology Graduate Program, University of California, Berkeley, Berkeley, CA 94720–3104, USA.
2. Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA 94720–3104, USA.
3. Endocrinology Graduate Program, University of California, Berkeley, Berkeley, CA 94720–3104, USA.
4. Departments of Chemistry and Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720–3104, USA.