1. The antiarrhythmic compound efsevin directly modulates voltage‐dependent anion channel 2 by binding to its inner wall and enhancing mitochondrial Ca2+ uptake
- Author
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Philip A. Gurnev, Ohyun Kwon, Robin Kopp, Johann Schredelseker, Annette Nicke, Nathan J. Dupper, Anna Schedel, Fabiola Wilting, and Thomas Gudermann
- Subjects
0301 basic medicine ,Voltage-dependent anion channel ,Gating ,Mitochondrion ,03 medical and health sciences ,0302 clinical medicine ,Animals ,Myocytes, Cardiac ,Binding site ,Lipid bilayer ,Zebrafish ,Pharmacology ,biology ,Chemistry ,Voltage-Dependent Anion Channel 2 ,Biological Transport ,Zebrafish Proteins ,Research Papers ,Mitochondria ,030104 developmental biology ,Docking (molecular) ,Mitochondrial Membranes ,biology.protein ,Biophysics ,Calcium ,Heterologous expression ,VDAC2 ,030217 neurology & neurosurgery ,Research Paper - Abstract
Background and Purpose The synthetic compound efsevin was recently identified to suppress arrhythmogenesis in models of cardiac arrhythmia, making it a promising candidate for antiarrhythmic therapy. Its activity was shown to be dependent on the voltage‐dependent anion channel 2 (VDAC2) in the outer mitochondrial membrane. Here, we investigated the molecular mechanism of the efsevin–VDAC2 interaction. Experimental Approach To evaluate the functional interaction of efsevin and VDAC2, we measured currents through recombinant VDAC2 in planar lipid bilayers. Using molecular ligand‐protein docking and mutational analysis, we identified the efsevin binding site on VDAC2. Finally, physiological consequences of the efsevin‐induced modulation of VDAC2 were analysed in HL‐1 cardiomyocytes. Key Results In lipid bilayers, efsevin reduced VDAC2 conductance and shifted the channel's open probability towards less anion‐selective closed states. Efsevin binds to a binding pocket formed by the inner channel wall and the pore‐lining N‐terminal α‐helix. Exchange of amino acids N207, K236 and N238 within this pocket for alanines abolished the channel's efsevin‐responsiveness. Upon heterologous expression in HL‐1 cardiomyocytes, both channels, wild‐type VDAC2 and the efsevin‐insensitive VDAC2AAA restored mitochondrial Ca2+ uptake, but only wild‐type VDAC2 was sensitive to efsevin. Conclusion and Implications In summary, our data indicate a direct interaction of efsevin with VDAC2 inside the channel pore that leads to modified gating and results in enhanced SR‐mitochondria Ca2+ transfer. This study sheds new light on the function of VDAC2 and provides a basis for structure‐aided chemical optimization of efsevin.
- Published
- 2020