Mechanosensitive pore opening of a prokaryotic voltage-gated sodium channel.

Autor: Strege PR; Enteric Neuroscience Program (ENSP), Division of Gastroenterology & Hepatology, Department of Medicine, Mayo Clinic, Rochester, United States., Cowan LM; Enteric Neuroscience Program (ENSP), Division of Gastroenterology & Hepatology, Department of Medicine, Mayo Clinic, Rochester, United States., Alcaino C; Enteric Neuroscience Program (ENSP), Division of Gastroenterology & Hepatology, Department of Medicine, Mayo Clinic, Rochester, United States., Mazzone A; Enteric Neuroscience Program (ENSP), Division of Gastroenterology & Hepatology, Department of Medicine, Mayo Clinic, Rochester, United States., Ahern CA; Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, United States., Milescu LS; Department of Biology, University of Maryland, College Park, College Park, United States., Farrugia G; Enteric Neuroscience Program (ENSP), Division of Gastroenterology & Hepatology, Department of Medicine, Mayo Clinic, Rochester, United States.; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, United States., Beyder A; Enteric Neuroscience Program (ENSP), Division of Gastroenterology & Hepatology, Department of Medicine, Mayo Clinic, Rochester, United States.; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, United States.
Jazyk: angličtina
Zdroj: ELife [Elife] 2023 Mar 13; Vol. 12. Date of Electronic Publication: 2023 Mar 13.
DOI: 10.7554/eLife.79271
Abstrakt: Voltage-gated ion channels (VGICs) 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. VGICs 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 Bacillus halodurans , 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 V 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 VGICs, including Na V 1.5.
Competing Interests: PS, LC, CA, AM, CA, LM, GF, AB No competing interests declared
(© 2023, Strege et al.)
Databáze: MEDLINE
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