Activation pathway of the human voltage-gated proton channel
- 1University of Maryland School of Pharmacy
Abstract
Many protein functions are coupled to proton transfer, yet the underlying mechanisms remain extremely difficult to resolve by experiment or conventional molecular dynamics (MD) simulations. The human voltage-gated proton channel HV1 (hHV1) plays key roles in human physiology, but how voltage and pH together drive its activation remains unresolved. Experimental structures of hHV1 are limited to the X-ray structure of a mouse chimera and NMR models of a truncated hHV1, both representing an intermediate resting state. Here we determine the activation pathway of hHV1, together with structural models of its resting and activated states, using an approach that integrates all-atom continuous constant-pH MD (CpHMD), weighted-ensemble (WE) path sampling, and AlphaFold modeling. Starting from an AlphaFold model selected for consistency with resting-state experimental data, over 100 s of simulations reveal a mechanism in which transmembrane voltage, assisted by proton titration, drives an outward displacement of the transmembrane segment S4 accompanied by a one-click reorganization of countercharge pairings. These events are enabled by a delicately balanced electrostatic landscape and pH-modulated breathing motions in the resting state that prime the channel for protonation-state switches upon voltage sensing, a principle that may underlie other proton-coupled voltage-gating processes. The simulations also uncover lipid-binding sites at which POPG selectively stabilizes the S4-up conformation, whereas POPE can stabilize either state. These predictions are validated against extensive electrophysiology, mutagenesis data, and new smFRET experiments, which support the one-click S4 displacement and the lipid effects. WE-CpHMD, implemented in the AMBER package, is applicable to other proton-coupled processes that remain elusive.
Related
- Kinetic models of a K channel with 2 stage voltage sensor activation and an opening step
- Structural basis of voltage gating in a partially activated K+ channel
- The structural dynamics and molecular coupling in the slow inactivation of a prokaryotic voltage-gated sodium channel
- Distribution of voltage-gated sodium channel and acetylcholinesterase mutations in Bemisia tabaci species from the Democratic Republic of the Congo
- Voltage-gated sodium channel, Nav 1.8, regulates calcium dynamics in the dorsal root ganglion induced by cold nociceptive stimulus
BibTeX
@misc{shen2026activation,
title = {{Activation pathway of the human voltage-gated proton channel}},
author = {M. Shen and D. Kortzak and C. Jardin and S. Han and N. Felbinger and S. Wang and B. Pierce and B. Musset and T. E. DeCoursey and J. Shen},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.06.757015},
url = {https://www.biorxiv.org/content/10.64898/2026.10.06.757015v1},
note = {CC BY-NC},
}
RIS
TY - UNPB
TI - Activation pathway of the human voltage-gated proton channel
AU - M. Shen
AU - D. Kortzak
AU - C. Jardin
AU - S. Han
AU - N. Felbinger
AU - S. Wang
AU - B. Pierce
AU - B. Musset
AU - T. E. DeCoursey
AU - J. Shen
PY - 2026
DA - 2026/10/06
PB - bioRxiv
DO - 10.64898/2026.10.06.757015
UR - https://www.biorxiv.org/content/10.64898/2026.10.06.757015v1
AB - Many protein functions are coupled to proton transfer, yet the underlying mechanisms remain extremely difficult to resolve by experiment or conventional molecular dynamics (MD) simulations. The human voltage-gated proton channel HV1 (hHV1) plays key roles in human physiology, but how voltage and pH together drive its activation remains unresolved. Experimental structures of hHV1 are limited to the X-ray structure of a mouse chimera and NMR models of a truncated hHV1, both representing an intermediate resting state. Here we determine the activation pathway of hHV1, together with structural models of its resting and activated states, using an approach that integrates all-atom continuous constant-pH MD (CpHMD), weighted-ensemble (WE) path sampling, and AlphaFold modeling. Starting from an AlphaFold model selected for consistency with resting-state experimental data, over 100 s of simulations reveal a mechanism in which transmembrane voltage, assisted by proton titration, drives an outward displacement of the transmembrane segment S4 accompanied by a one-click reorganization of countercharge pairings. These events are enabled by a delicately balanced electrostatic landscape and pH-modulated breathing motions in the resting state that prime the channel for protonation-state switches upon voltage sensing, a principle that may underlie other proton-coupled voltage-gating processes. The simulations also uncover lipid-binding sites at which POPG selectively stabilizes the S4-up conformation, whereas POPE can stabilize either state. These predictions are validated against extensive electrophysiology, mutagenesis data, and new smFRET experiments, which support the one-click S4 displacement and the lipid effects. WE-CpHMD, implemented in the AMBER package, is applicable to other proton-coupled processes that remain elusive.
ER -