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Voltage and pH sensing by the voltage-gated proton channel, H(V)1

Voltage-gated proton channels are unique ion channels, membrane proteins that allow protons but no other ions to cross cell membranes. They are found in diverse species, from unicellular marine life to humans. In all cells, their function requires that they open and conduct current only under certai...

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Detalles Bibliográficos
Autor principal: DeCoursey, Thomas E.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5938591/
https://www.ncbi.nlm.nih.gov/pubmed/29643227
http://dx.doi.org/10.1098/rsif.2018.0108
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author DeCoursey, Thomas E.
author_facet DeCoursey, Thomas E.
author_sort DeCoursey, Thomas E.
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description Voltage-gated proton channels are unique ion channels, membrane proteins that allow protons but no other ions to cross cell membranes. They are found in diverse species, from unicellular marine life to humans. In all cells, their function requires that they open and conduct current only under certain conditions, typically when the electrochemical gradient for protons is outwards. Consequently, these proteins behave like rectifiers, conducting protons out of cells. Their activity has electrical consequences and also changes the pH on both sides of the membrane. Here we summarize what is known about the way these proteins sense the membrane potential and the pH inside and outside the cell. Currently, it is hypothesized that membrane potential is sensed by permanently charged arginines (with very high pK(a)) within the protein, which results in parts of the protein moving to produce a conduction pathway. The mechanism of pH sensing appears to involve titratable side chains of particular amino acids. For this purpose their pK(a) needs to be within the operational pH range. We propose a ‘counter-charge’ model for pH sensing in which electrostatic interactions within the protein are selectively disrupted by protonation of internally or externally accessible groups.
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spelling pubmed-59385912018-05-08 Voltage and pH sensing by the voltage-gated proton channel, H(V)1 DeCoursey, Thomas E. J R Soc Interface Review Articles Voltage-gated proton channels are unique ion channels, membrane proteins that allow protons but no other ions to cross cell membranes. They are found in diverse species, from unicellular marine life to humans. In all cells, their function requires that they open and conduct current only under certain conditions, typically when the electrochemical gradient for protons is outwards. Consequently, these proteins behave like rectifiers, conducting protons out of cells. Their activity has electrical consequences and also changes the pH on both sides of the membrane. Here we summarize what is known about the way these proteins sense the membrane potential and the pH inside and outside the cell. Currently, it is hypothesized that membrane potential is sensed by permanently charged arginines (with very high pK(a)) within the protein, which results in parts of the protein moving to produce a conduction pathway. The mechanism of pH sensing appears to involve titratable side chains of particular amino acids. For this purpose their pK(a) needs to be within the operational pH range. We propose a ‘counter-charge’ model for pH sensing in which electrostatic interactions within the protein are selectively disrupted by protonation of internally or externally accessible groups. The Royal Society 2018-04 2018-04-11 /pmc/articles/PMC5938591/ /pubmed/29643227 http://dx.doi.org/10.1098/rsif.2018.0108 Text en © 2018 The Author. http://creativecommons.org/licenses/by/4.0/ Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.
spellingShingle Review Articles
DeCoursey, Thomas E.
Voltage and pH sensing by the voltage-gated proton channel, H(V)1
title Voltage and pH sensing by the voltage-gated proton channel, H(V)1
title_full Voltage and pH sensing by the voltage-gated proton channel, H(V)1
title_fullStr Voltage and pH sensing by the voltage-gated proton channel, H(V)1
title_full_unstemmed Voltage and pH sensing by the voltage-gated proton channel, H(V)1
title_short Voltage and pH sensing by the voltage-gated proton channel, H(V)1
title_sort voltage and ph sensing by the voltage-gated proton channel, h(v)1
topic Review Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5938591/
https://www.ncbi.nlm.nih.gov/pubmed/29643227
http://dx.doi.org/10.1098/rsif.2018.0108
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