Zinc inhibits the voltage-gated proton channel HCNL1.

IF 3.2 3区 生物学 Q2 BIOPHYSICS
Biophysical journal Pub Date : 2024-12-17 Epub Date: 2024-08-28 DOI:10.1016/j.bpj.2024.08.018
Makoto F Kuwabara, Joschua Klemptner, Julia Muth, Emilia De Martino, Dominik Oliver, Thomas K Berger
{"title":"Zinc inhibits the voltage-gated proton channel HCNL1.","authors":"Makoto F Kuwabara, Joschua Klemptner, Julia Muth, Emilia De Martino, Dominik Oliver, Thomas K Berger","doi":"10.1016/j.bpj.2024.08.018","DOIUrl":null,"url":null,"abstract":"<p><p>Voltage-gated ion channels allow ion flux across biological membranes in response to changes in the membrane potential. HCNL1 is a recently discovered voltage-gated ion channel that selectively conducts protons through its voltage-sensing domain (VSD), reminiscent of the well-studied depolarization-activated Hv1 proton channel. However, HCNL1 is activated by hyperpolarization, allowing the influx of protons, which leads to an intracellular acidification in zebrafish sperm. Zinc ions (Zn<sup>2+</sup>) are important cofactors in many proteins and essential for sperm physiology. Proton channels such as Hv1 and Otopetrin1 are inhibited by Zn<sup>2+</sup>. We investigated the effect of Zn<sup>2+</sup> on heterologously expressed HCNL1 channels using electrophysiological and fluorometric techniques. Extracellular Zn<sup>2+</sup> inhibits HCNL1 currents with an apparent half-maximal inhibition (IC<sub>50</sub>) of 26 μM. Zn<sup>2+</sup> slows voltage-dependent current kinetics, shifts the voltage-dependent activation to more negative potentials, and alters hyperpolarization-induced conformational changes of the voltage sensor. Our data suggest that extracellular Zn<sup>2+</sup> inhibits HCNL1 currents by multiple mechanisms, including modulation of channel gating. Two histidine residues located at the extracellular side of the VSD might weakly contribute to Zn<sup>2+</sup> coordination: mutants with either histidine replaced with alanine show modest shifts of the IC<sub>50</sub> values to higher concentrations. Interestingly, Zn<sup>2+</sup> inhibits HCNL1 at even lower concentrations from the intracellular side (IC<sub>50</sub> ≈ 0.5 μM). A histidine residue at the intracellular end of S1 (position 50) is important for Zn<sup>2+</sup> binding: much higher Zn<sup>2+</sup> concentrations are required to inhibit the mutant HCNL1-H50A (IC<sub>50</sub> ≈ 106 μM). We anticipate that Zn<sup>2+</sup> will be a useful ion to study the structure-function relationship of HCNL1 as well as the physiological role of HCNL1 in zebrafish sperm.</p>","PeriodicalId":8922,"journal":{"name":"Biophysical journal","volume":" ","pages":"4256-4265"},"PeriodicalIF":3.2000,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Biophysical journal","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1016/j.bpj.2024.08.018","RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/8/28 0:00:00","PubModel":"Epub","JCR":"Q2","JCRName":"BIOPHYSICS","Score":null,"Total":0}
引用次数: 0

Abstract

Voltage-gated ion channels allow ion flux across biological membranes in response to changes in the membrane potential. HCNL1 is a recently discovered voltage-gated ion channel that selectively conducts protons through its voltage-sensing domain (VSD), reminiscent of the well-studied depolarization-activated Hv1 proton channel. However, HCNL1 is activated by hyperpolarization, allowing the influx of protons, which leads to an intracellular acidification in zebrafish sperm. Zinc ions (Zn2+) are important cofactors in many proteins and essential for sperm physiology. Proton channels such as Hv1 and Otopetrin1 are inhibited by Zn2+. We investigated the effect of Zn2+ on heterologously expressed HCNL1 channels using electrophysiological and fluorometric techniques. Extracellular Zn2+ inhibits HCNL1 currents with an apparent half-maximal inhibition (IC50) of 26 μM. Zn2+ slows voltage-dependent current kinetics, shifts the voltage-dependent activation to more negative potentials, and alters hyperpolarization-induced conformational changes of the voltage sensor. Our data suggest that extracellular Zn2+ inhibits HCNL1 currents by multiple mechanisms, including modulation of channel gating. Two histidine residues located at the extracellular side of the VSD might weakly contribute to Zn2+ coordination: mutants with either histidine replaced with alanine show modest shifts of the IC50 values to higher concentrations. Interestingly, Zn2+ inhibits HCNL1 at even lower concentrations from the intracellular side (IC50 ≈ 0.5 μM). A histidine residue at the intracellular end of S1 (position 50) is important for Zn2+ binding: much higher Zn2+ concentrations are required to inhibit the mutant HCNL1-H50A (IC50 ≈ 106 μM). We anticipate that Zn2+ will be a useful ion to study the structure-function relationship of HCNL1 as well as the physiological role of HCNL1 in zebrafish sperm.

锌抑制电压门控质子通道 HCNL1。
电压门控离子通道能使离子流随膜电位的变化穿过生物膜。HCNL1 是最近发现的一种电压门控离子通道,可通过其电压感应结构域(VSD)选择性地传导质子,这让人联想到研究得很透彻的去极化激活 Hv1 质子通道。然而,HCNL1 通过超极化激活,允许质子流入,从而导致斑马鱼精子细胞内酸化。锌离子(Zn2+)是许多蛋白质的重要辅助因子,对精子的生理机能至关重要。质子通道(如 Hv1 和 Otopetrin1)会受到 Zn2+ 的抑制。我们利用电生理学和荧光测定技术研究了 Zn2+ 对异源表达的 HCNL1 通道的影响。细胞外 Zn2+ 可抑制 HCNL1 电流,其表观半最大抑制作用(IC50)为 26 μM。Zn2+ 可减慢电压依赖性电流动力学,将电压依赖性激活转移到更负的电位,并改变超极化诱导的电压传感器构象变化。我们的数据表明,细胞外 Zn2+ 通过多种机制抑制 HCNL1 电流,包括调节通道门控。位于 VSD 细胞外侧的两个组氨酸残基可能对 Zn2+ 的配位有微弱的作用:用丙氨酸取代其中一个组氨酸的突变体显示 IC50s 稍微向高浓度移动。有趣的是,Zn2+ 从细胞内侧抑制 HCNL1 的浓度甚至更低(IC50 ≈ 0.5 μM)。S1 细胞内末端(第 50 位)的组氨酸残基对 Zn2+ 的结合非常重要:抑制突变体 HCNL1-H50A 需要更高浓度的 Zn2+(IC50 ≈ 106 μM)。我们预计 Zn2+ 将成为研究 HCNL1 的结构-功能关系以及 HCNL1 在斑马鱼精子中的生理作用的有用离子。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
求助全文
约1分钟内获得全文 求助全文
来源期刊
Biophysical journal
Biophysical journal 生物-生物物理
CiteScore
6.10
自引率
5.90%
发文量
3090
审稿时长
2 months
期刊介绍: BJ publishes original articles, letters, and perspectives on important problems in modern biophysics. The papers should be written so as to be of interest to a broad community of biophysicists. BJ welcomes experimental studies that employ quantitative physical approaches for the study of biological systems, including or spanning scales from molecule to whole organism. Experimental studies of a purely descriptive or phenomenological nature, with no theoretical or mechanistic underpinning, are not appropriate for publication in BJ. Theoretical studies should offer new insights into the understanding ofexperimental results or suggest new experimentally testable hypotheses. Articles reporting significant methodological or technological advances, which have potential to open new areas of biophysical investigation, are also suitable for publication in BJ. Papers describing improvements in accuracy or speed of existing methods or extra detail within methods described previously are not suitable for BJ.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
copy
已复制链接
快去分享给好友吧!
我知道了
右上角分享
点击右上角分享
0
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信