A Mechanistic Basis for Inhibition of TREK-2 K2P Channels by Norfluoxetine
A Mechanistic Basis for Inhibition of TREK-2 K2P Channels by Norfluoxetine
ABSTRACT The TREK subfamily of Two-Pore Domain (K2P) K+ channels are inhibited by low micromolar concentrations of fluoxetine and its metabolite, norfluoxetine (NFx). Although not the principal target of this antidepressant, TREK channel inhibition by NFx has provided important insights into the conformational changes associated with channel gating and highlighted the role of the selectivity filter in this process. Yet despite the availability of TREK-2 crystal structures with NFx bound, the precise mechanisms which underlie NFx inhibition remain elusive. Such investigations ideally require examining the effects of the drug on single channel behavior. However, wild-type TREK channels normally exhibit a very low open probability which makes analysis of their inhibition at the single channel level extremely challenging. In this study, we show how the unique behavior of single TREK-2 channels reconstituted in lipid bilayers can be used to study NFx inhibition in detail. Our results reveal the primary mechanism of NFx inhibition is a complex allosteric process that results in both a reduced open probability and single channel conductance. Furthermore, we show the transduction mechanism involved in NFx inhibition can be disrupted by the action of ML335, and can also be subject to desensitization. We also uncover several voltage-dependent effects of NFx inhibition. In addition, we propose a gating scheme that accounts these effects and which provide important insights into the action of agonists and antagonists on K2P channel function.
Conrad Linus J.、Rao Shanlin、R?dstr?m Karin E. J.、Carpenter Elisabeth P.、Baukrowitz Thomas、Tucker Stephen J、Rathje Kristin、Proks Peter、Schewe Marcus
Clarendon Laboratory, Department of Physics, University of Oxford||OXION Initiative in Ion Channels and Disease, University of OxfordDepartment of Biochemistry, University of OxfordCentre for Medicines Discovery, University of OxfordOXION Initiative in Ion Channels and Disease, University of Oxford||Centre for Medicines Discovery, University of OxfordDepartment of Physiology, University of KielClarendon Laboratory, Department of Physics, University of Oxford||OXION Initiative in Ion Channels and Disease, University of OxfordDepartment of Physiology, University of KielClarendon Laboratory, Department of Physics, University of Oxford||OXION Initiative in Ion Channels and Disease, University of OxfordDepartment of Physiology, University of Kiel
基础医学生理学生物化学
K2P channelKCNK10TREK-2NorfluoxetineML335K+ channel gating
Conrad Linus J.,Rao Shanlin,R?dstr?m Karin E. J.,Carpenter Elisabeth P.,Baukrowitz Thomas,Tucker Stephen J,Rathje Kristin,Proks Peter,Schewe Marcus.A Mechanistic Basis for Inhibition of TREK-2 K2P Channels by Norfluoxetine[EB/OL].(2025-03-28)[2025-05-02].https://www.biorxiv.org/content/10.1101/2020.10.29.360966.点此复制
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