1. Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA.
2. Cell Design Institute, University of California, San Francisco, San Francisco, CA 94158, USA.
3. Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA.
4. Department of Medicine, University of California, San Francisco, San Francisco, CA 94158, USA.
5. Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
6. Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94158, USA.