The HCN domain couples voltage gating and cAMP response in Hyperpolarization-activated Cyclic Nucleotide-gated channels
- University of Milan, Italy
- Technische Universität Darmstadt, Germany
- Columbia University, United States
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels control spontaneous electrical activity in heart and brain. Binding of cAMP to the cyclic nucleotide-binding domain (CNBD) facilitates channel opening by relieving a tonic inhibition exerted by the CNBD. Despite high resolution structures of the HCN1 channel in the cAMP bound and unbound states, the structural mechanism coupling ligand binding to channel gating is unknown. Here we show that the recently identified helical HCN-domain (HCND) mechanically couples the CNBD and channel voltage sensing domain (VSD), possibly acting as a sliding crank that converts the planar rotational movement of the CNBD into a rotational upward displacement of the VSD. This mode of operation and its impact on channel gating are confirmed by computational and experimental data showing that disruption of critical contacts between the three domains affects cAMP- and voltage-dependent gating in three HCN isoforms.
Article and author information
Author details
Gerardo Abbandonato
Funding
Fondazione Cariplo (2014-0796)
- Anna Moroni
H2020 European Research Council (ERC-2015-AdG 695078-noMAGIC)
- Anna Moroni
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- László Csanády, Semmelweis University, Hungary
Publication history
- Received: June 25, 2019
- Accepted: November 22, 2019
- Accepted Manuscript published: November 26, 2019 (version 1)
- Version of Record published: December 5, 2019 (version 2)
Copyright
© 2019, Porro et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Further reading
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- Structural Biology and Molecular Biophysics
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- Structural Biology and Molecular Biophysics
