[1] NICHD, ERRB SMST, NIH, Bethesda, MD USA
[2] Univ Calif San Francisco, Program Chem & Chem Biol, San Francisco, CA 94143 USA
[3] Univ Calif San Francisco, Howard Hughes Med Inst, San Francisco, CA 94143 USA
[4] Univ Calif San Francisco, Dept Cellular & Mol Pharmacol, San Francisco, CA 94143 USA