# Structural dynamics underlying voltage and pH gating of the human proton channel

> **NIH NIH R15** · UNIVERSITY OF MISSOURI KANSAS CITY · 2022 · $62,708

## Abstract

Project Summary/Abstract
Voltage-gated proton (Hv) channels carry robust proton currents across membranes and are gated by both
voltage and transmembrane pH gradient (∆pH). They normally serve as proton extruders to maintain the pH
homeostasis of metabolically active cells. In phagocytes, human Hv1 (hHv1) channels compensate for charge
and pH imbalance during the respiratory burst of NADPH oxidase to promote the production of reactive oxygen
species (ROS) for pathogen defense. The sperm hHv1 channels trigger intracellular alkylation essential for
capacitation. The hHv1 channel also highly correlates with cancer invasiveness and ischemic neuronal cell
death. Voltage and ∆pH gating are two fundamental biophysical properties determining the dynamics of proton
currents through Hv channels, which in turn underlie their physiological and pathophysiological roles in the
cells mentioned above. Funded by the parent award, we examined the conformational dynamics of the purified
hHv1 proteins in liposomes using single molecule FRET (Fluorescence Resonance Energy Transfer). We have
provided the first glimpse of real-time conformational transitions in the hHv1 voltage sensor and showed that
both voltage and pH gate the hHv1 channel by modifying the conformational landscapes of the voltage sensor.
We also generated a kinetic model to explain how voltage pH interplay determines hHv1 channel gating. To
maximize the impacts of the exciting findings that have been made, we need to obtain accurate rate constants
of conformational transitions described by the kinetic model, which can provide key mechanistic insights into
the voltage sensing and gating in other voltage-gated cation channels. The administrative supplement for the
accessory will upgrade the existing TIRF (Total Internal Reflection Fluorescence) microscope for single
molecule FRET imaging, which will provide the critical technical strength to maximize the scientific impacts of
the parent award. The accessory contains the patch-clamp module for electrophysiological recording and the
single molecule FRET imaging module containing a high-speed sCMOS (scientific Complementary Metal-
Oxide-Semiconductor) camera reaching a time resolution close to 1 millisecond. With the accessory, the
existing TIRF microscope will be upgraded to perform single molecule FRET imaging and electrophysiological
recordings simultaneously. As a result, we will be able to control the voltage and pH applied to hHv1 channels
more precisely to get accurate rate constants of the conformational transitions in the hHv1 channel induced by
pH and voltage. In addition, we will be able to examine the channel gating dynamics by patch-clamp recordings
and conformational dynamics using single molecule FRET imaging simultaneously, thus defining the structure
and function relationship directly.

## Key facts

- **NIH application ID:** 10610652
- **Project number:** 3R15GM137315-01S1
- **Recipient organization:** UNIVERSITY OF MISSOURI KANSAS CITY
- **Principal Investigator:** SHIZHEN WANG
- **Activity code:** R15 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $62,708
- **Award type:** 3
- **Project period:** 2020-05-01 → 2023-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10610652

## Citation

> US National Institutes of Health, RePORTER application 10610652, Structural dynamics underlying voltage and pH gating of the human proton channel (3R15GM137315-01S1). Retrieved via AI Analytics 2026-06-11 from https://api.ai-analytics.org/grant/nih/10610652. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*