About the Authors
Burnham Institute for Medical Research, La Jolla, California, United States of America
Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont, United States of America
The authors have declared that no competing interests exist.
Conceived and designed the experiments: DH NV KT SL. Performed the experiments: LH. Analyzed the data: DH NV HL. Contributed reagents/materials/analysis tools: DH NV KT SL. Wrote the paper: DH NV KT SL.