Multistate Structural Modeling and Voltage-Clamp Analysis of Epilepsy/Autism Mutation Kv10.2–R327H Demonstrate the Role of This Residue in Stabilizing the Channel Closed State
- Yang Yang1,2,3,*,
- Dmytro V. Vasylyev1,2,3,*,
- Fadia Dib-Hajj1,2,3,
- Krishna R. Veeramah4,
- Michael F. Hammer4,
- Sulayman D. Dib-Hajj1,2,3, and
- Stephen G. Waxman1,2,3
- 1Department of Neurology and
- 2Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut 06510,
- 3Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut 06516, and
- 4Arizona Research Laboratories Division of Biotechnology, University of Arizona, Tucson, Arizona 85721
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Author contributions: Y.Y., D.V.V., S.D.D.-H., and S.G.W. designed research; Y.Y. and D.V.V. performed research; F.D.-H., K.R.V., and M.F.H. contributed unpublished reagents/analytic tools; Y.Y., D.V.V., and S.D.D.-H. analyzed data; Y.Y., D.V.V., S.D.D.-H., and S.G.W. wrote the paper.
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↵*Y.Y. and D.V.V. contributed equally to this work.
Abstract
Voltage-gated potassium channel Kv10.2 (KCNH5) is expressed in the nervous system, but its functions and involvement in human disease are poorly understood. We studied a human Kv10.2 channel mutation (R327H) recently identified in a child with epileptic encephalopathy and autistic features. Using multistate structural modeling, we demonstrate that the Arg327 residue in the S4 helix of voltage-sensing domain has strong ionic interactions with negatively charged residues within the S1–S3 helices in the resting (closed) and early-activation state but not in the late-activation and fully-activated (open) state. The R327H mutation weakens ionic interactions between residue 327 and these negatively charged residues, thus favoring channel opening. Voltage-clamp analysis showed a strong hyperpolarizing (∼70 mV) shift of voltage dependence of activation and an acceleration of activation. Our results demonstrate the critical role of the Arg327 residue in stabilizing the channel closed state and explicate for the first time the structural and functional change of a Kv10.2 channel mutation associated with neurological disease.
- Received May 29, 2013.
- Revision received September 4, 2013.
- Accepted September 10, 2013.
- Copyright © 2013 the authors 0270-6474/13/3316586-08$15.00/0
