Molecular mechanism of Zn2+ inhibition of a voltage-gated proton channel

Feng Qiu, Adam Chamberlin, Briana M. Watkins, Alina Ionescu, Marta Elena Perez, Rene Barro, Carlos González, Sergei Y. Noskov, Hans P Larsson

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Voltage-gated proton (Hv1) channels are involved in many physiological processes, such as pH homeostasis and the innate immune response. Zn2+ is an important physiological inhibitor of Hv1. Sperm cells are quiescent in the male reproductive system due to Zn2+ inhibition of Hv1 channels, but become active once introduced into the low-Zn2+-concentration environment of the female reproductive tract. How Zn2+ inhibits Hv1 is not completely understood. In this study, we use the voltage clamp fluorometry technique to identify the molecular mechanism of Zn2+ inhibition of Hv1. We find that Zn2+ binds to both the activated closed and resting closed states of the Hv1 channel, thereby inhibiting both voltage sensor motion and gate opening. Mutations of some Hv1 residues affect only Zn2+ inhibition of the voltage sensor motion, whereas mutations of other residues also affect Zn2+ inhibition of gate opening. These effects are similar in monomeric and dimeric Hv1 channels, suggesting that the Zn2+-binding sites are localized within each subunit of the dimeric Hv1. We propose that Zn2+ binding has two major effects on Hv1: (i) at low concentrations, Zn2+ binds to one site and prevents the opening conformational change of the pore of Hv1, thereby inhibiting proton conduction; and (ii) at high concentrations, Zn2+, in addition, binds to a second site and inhibits the outward movement of the voltage sensor of Hv1. Elucidating the molecular mechanism of how Zn2+ inhibits Hv1 will further our understanding of Hv1 function and might provide valuable information for future drug development for Hv1 channels.

Original languageEnglish (US)
Pages (from-to)E5962-E5971
JournalProceedings of the National Academy of Sciences of the United States of America
Volume113
Issue number40
DOIs
StatePublished - Oct 4 2016

Fingerprint

Protons
Physiological Phenomena
Fluorometry
Mutation
Patch-Clamp Techniques
Innate Immunity
Spermatozoa
Homeostasis
Binding Sites
Pharmaceutical Preparations

Keywords

  • Hv1
  • Inhibition
  • Molecular model
  • Voltage-gated proton channel
  • Zn2

ASJC Scopus subject areas

  • General

Cite this

Molecular mechanism of Zn2+ inhibition of a voltage-gated proton channel. / Qiu, Feng; Chamberlin, Adam; Watkins, Briana M.; Ionescu, Alina; Perez, Marta Elena; Barro, Rene; González, Carlos; Noskov, Sergei Y.; Larsson, Hans P.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 113, No. 40, 04.10.2016, p. E5962-E5971.

Research output: Contribution to journalArticle

Qiu, Feng ; Chamberlin, Adam ; Watkins, Briana M. ; Ionescu, Alina ; Perez, Marta Elena ; Barro, Rene ; González, Carlos ; Noskov, Sergei Y. ; Larsson, Hans P. / Molecular mechanism of Zn2+ inhibition of a voltage-gated proton channel. In: Proceedings of the National Academy of Sciences of the United States of America. 2016 ; Vol. 113, No. 40. pp. E5962-E5971.
@article{afc77e488d9444b984790d6a7353797b,
title = "Molecular mechanism of Zn2+ inhibition of a voltage-gated proton channel",
abstract = "Voltage-gated proton (Hv1) channels are involved in many physiological processes, such as pH homeostasis and the innate immune response. Zn2+ is an important physiological inhibitor of Hv1. Sperm cells are quiescent in the male reproductive system due to Zn2+ inhibition of Hv1 channels, but become active once introduced into the low-Zn2+-concentration environment of the female reproductive tract. How Zn2+ inhibits Hv1 is not completely understood. In this study, we use the voltage clamp fluorometry technique to identify the molecular mechanism of Zn2+ inhibition of Hv1. We find that Zn2+ binds to both the activated closed and resting closed states of the Hv1 channel, thereby inhibiting both voltage sensor motion and gate opening. Mutations of some Hv1 residues affect only Zn2+ inhibition of the voltage sensor motion, whereas mutations of other residues also affect Zn2+ inhibition of gate opening. These effects are similar in monomeric and dimeric Hv1 channels, suggesting that the Zn2+-binding sites are localized within each subunit of the dimeric Hv1. We propose that Zn2+ binding has two major effects on Hv1: (i) at low concentrations, Zn2+ binds to one site and prevents the opening conformational change of the pore of Hv1, thereby inhibiting proton conduction; and (ii) at high concentrations, Zn2+, in addition, binds to a second site and inhibits the outward movement of the voltage sensor of Hv1. Elucidating the molecular mechanism of how Zn2+ inhibits Hv1 will further our understanding of Hv1 function and might provide valuable information for future drug development for Hv1 channels.",
keywords = "Hv1, Inhibition, Molecular model, Voltage-gated proton channel, Zn2",
author = "Feng Qiu and Adam Chamberlin and Watkins, {Briana M.} and Alina Ionescu and Perez, {Marta Elena} and Rene Barro and Carlos Gonz{\'a}lez and Noskov, {Sergei Y.} and Larsson, {Hans P}",
year = "2016",
month = "10",
day = "4",
doi = "10.1073/pnas.1604082113",
language = "English (US)",
volume = "113",
pages = "E5962--E5971",
journal = "Proceedings of the National Academy of Sciences of the United States of America",
issn = "0027-8424",
number = "40",

}

TY - JOUR

T1 - Molecular mechanism of Zn2+ inhibition of a voltage-gated proton channel

AU - Qiu, Feng

AU - Chamberlin, Adam

AU - Watkins, Briana M.

AU - Ionescu, Alina

AU - Perez, Marta Elena

AU - Barro, Rene

AU - González, Carlos

AU - Noskov, Sergei Y.

AU - Larsson, Hans P

PY - 2016/10/4

Y1 - 2016/10/4

N2 - Voltage-gated proton (Hv1) channels are involved in many physiological processes, such as pH homeostasis and the innate immune response. Zn2+ is an important physiological inhibitor of Hv1. Sperm cells are quiescent in the male reproductive system due to Zn2+ inhibition of Hv1 channels, but become active once introduced into the low-Zn2+-concentration environment of the female reproductive tract. How Zn2+ inhibits Hv1 is not completely understood. In this study, we use the voltage clamp fluorometry technique to identify the molecular mechanism of Zn2+ inhibition of Hv1. We find that Zn2+ binds to both the activated closed and resting closed states of the Hv1 channel, thereby inhibiting both voltage sensor motion and gate opening. Mutations of some Hv1 residues affect only Zn2+ inhibition of the voltage sensor motion, whereas mutations of other residues also affect Zn2+ inhibition of gate opening. These effects are similar in monomeric and dimeric Hv1 channels, suggesting that the Zn2+-binding sites are localized within each subunit of the dimeric Hv1. We propose that Zn2+ binding has two major effects on Hv1: (i) at low concentrations, Zn2+ binds to one site and prevents the opening conformational change of the pore of Hv1, thereby inhibiting proton conduction; and (ii) at high concentrations, Zn2+, in addition, binds to a second site and inhibits the outward movement of the voltage sensor of Hv1. Elucidating the molecular mechanism of how Zn2+ inhibits Hv1 will further our understanding of Hv1 function and might provide valuable information for future drug development for Hv1 channels.

AB - Voltage-gated proton (Hv1) channels are involved in many physiological processes, such as pH homeostasis and the innate immune response. Zn2+ is an important physiological inhibitor of Hv1. Sperm cells are quiescent in the male reproductive system due to Zn2+ inhibition of Hv1 channels, but become active once introduced into the low-Zn2+-concentration environment of the female reproductive tract. How Zn2+ inhibits Hv1 is not completely understood. In this study, we use the voltage clamp fluorometry technique to identify the molecular mechanism of Zn2+ inhibition of Hv1. We find that Zn2+ binds to both the activated closed and resting closed states of the Hv1 channel, thereby inhibiting both voltage sensor motion and gate opening. Mutations of some Hv1 residues affect only Zn2+ inhibition of the voltage sensor motion, whereas mutations of other residues also affect Zn2+ inhibition of gate opening. These effects are similar in monomeric and dimeric Hv1 channels, suggesting that the Zn2+-binding sites are localized within each subunit of the dimeric Hv1. We propose that Zn2+ binding has two major effects on Hv1: (i) at low concentrations, Zn2+ binds to one site and prevents the opening conformational change of the pore of Hv1, thereby inhibiting proton conduction; and (ii) at high concentrations, Zn2+, in addition, binds to a second site and inhibits the outward movement of the voltage sensor of Hv1. Elucidating the molecular mechanism of how Zn2+ inhibits Hv1 will further our understanding of Hv1 function and might provide valuable information for future drug development for Hv1 channels.

KW - Hv1

KW - Inhibition

KW - Molecular model

KW - Voltage-gated proton channel

KW - Zn2

UR - http://www.scopus.com/inward/record.url?scp=84989855550&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84989855550&partnerID=8YFLogxK

U2 - 10.1073/pnas.1604082113

DO - 10.1073/pnas.1604082113

M3 - Article

C2 - 27647906

AN - SCOPUS:84989855550

VL - 113

SP - E5962-E5971

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

SN - 0027-8424

IS - 40

ER -