Mechanosensitive pore opening of a prokaryotic voltage-gated sodium channel

Peter R Strege; Luke M Cowan; Constanza Alcaino; Amelia Mazzone; Christopher A Ahern; Lorin S Milescu; Gianrico Farrugia; Arthur Beyder

doi:10.7554/eLife.79271

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Mechanosensitive pore opening of a prokaryotic voltage-gated sodium channel

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Mechanosensitive pore opening of a prokaryotic voltage-gated sodium channel

Peter R Strege, Luke M Cowan, Constanza Alcaino, Amelia Mazzone, Christopher A Ahern, Lorin S Milescu, Gianrico Farrugia and Arthur Beyder

eLife, Vol.12, e79271

2023

DOI: 10.7554/eLife.79271

PMCID: PMC10038658

PMID: 36912788

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Abstract

Voltage-gated ion channels orchestrate electrical activities that drive mechanical functions in contractile tissues such as the heart and gut. In turn, contractions change membrane tension and impact ion channels. Voltage-gated ion channels are mechanosensitive, but the mechanisms of mechanosensitivity remain poorly understood. Here, we leverage the relative simplicity of NaChBac, a prokaryotic voltage-gated sodium channel from , to investigate mechanosensitivity. In whole-cell experiments on heterologously transfected HEK293 cells, shear stress reversibly altered the kinetic properties of NaChBac and increased its maximum current, comparably to the mechanosensitive eukaryotic sodium channel Na 1.5. In single-channel experiments, patch suction reversibly increased the open probability of a NaChBac mutant with inactivation removed. A simple kinetic mechanism featuring a mechanosensitive pore opening transition explained the overall response to force, whereas an alternative model with mechanosensitive voltage sensor activation diverged from the data. Structural analysis of NaChBac identified a large displacement of the hinged intracellular gate, and mutagenesis near the hinge diminished NaChBac mechanosensitivity, further supporting the proposed mechanism. Our results suggest that NaChBac is overall mechanosensitive due to the mechanosensitivity of a voltage-insensitive gating step associated with the pore opening. This mechanism may apply to eukaryotic voltage-gated ion channels, including Na 1.5.

Cell Biology

Structural Biology

molecular biophysics

Details

Title: Subtitle: Mechanosensitive pore opening of a prokaryotic voltage-gated sodium channel
Creators: Peter R Strege - Mayo Clinic
Luke M Cowan - Mayo Clinic
Constanza Alcaino - Mayo Clinic
Amelia Mazzone - Mayo Clinic
Christopher A Ahern - University of Iowa
Lorin S Milescu - University of Maryland, College Park
Gianrico Farrugia - Mayo Clinic
Arthur Beyder - Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, United States.
Resource Type: Journal article
Publication Details: eLife, Vol.12, e79271
DOI: 10.7554/eLife.79271
PMID: 36912788
PMCID: PMC10038658
NLM abbreviation: Elife
ISSN: 2050-084X
eISSN: 2050-084X
Grant note: DK052766 / NIDDK NIH HHS AT010875 / NIH HHS DK123549 / NIDDK NIH HHS
Language: English
Date published: 2023
Academic Unit: Molecular Physiology and Biophysics; Iowa Neuroscience Institute
Record Identifier: 9984378110302771

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