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Plant Aquaporin Gating Is Reversed by Phosphorylation on Intracellular Loop D—Evidence from Molecular Dynamics Simulations

Aquaporins (AQPs) constitute a wide and ancient protein family of transmembrane channels dedicated to the regulation of water exchange across biological membranes. In plants, higher numbers of AQP homologues have been conserved compared to other kingdoms of life such as in animals or in bacteria. As...

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Autores principales: Mom, Robin, Réty, Stéphane, Mocquet, Vincent, Auguin, Daniel
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10531447/
https://www.ncbi.nlm.nih.gov/pubmed/37762101
http://dx.doi.org/10.3390/ijms241813798
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author Mom, Robin
Réty, Stéphane
Mocquet, Vincent
Auguin, Daniel
author_facet Mom, Robin
Réty, Stéphane
Mocquet, Vincent
Auguin, Daniel
author_sort Mom, Robin
collection PubMed
description Aquaporins (AQPs) constitute a wide and ancient protein family of transmembrane channels dedicated to the regulation of water exchange across biological membranes. In plants, higher numbers of AQP homologues have been conserved compared to other kingdoms of life such as in animals or in bacteria. As an illustration of this plant-specific functional diversity, plasma membrane intrinsic proteins (PIPs, i.e., a subfamily of plant AQPs) possess a long intracellular loop D, which can gate the channel by changing conformation as a function of the cellular environment. However, even though the closure of the AQP by loop D conformational changes is well described, the opening of the channel, on the other hand, is still misunderstood. Several studies have pointed to phosphorylation events as the trigger for the transition from closed- to open-channel states. Nonetheless, no clear answer has been obtained yet. Hence, in order to gain a more complete grasp of plant AQP regulation through this intracellular loop D gating, we investigated the opening of the channel in silico through molecular dynamics simulations of the crystallographic structure of Spinacia oleracea PIP2;1 (SoPIP2;1). Through this technique, we addressed the mechanistic details of these conformational changes, which eventually allowed us to propose a molecular mechanism for PIP functional regulation by loop D phosphorylation. More precisely, our results highlight the phosphorylation of loop D serine 188 as a trigger of SoPIP2;1 water channel opening. Finally, we discuss the significance of this result for the study of plant AQP functional diversity.
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spelling pubmed-105314472023-09-28 Plant Aquaporin Gating Is Reversed by Phosphorylation on Intracellular Loop D—Evidence from Molecular Dynamics Simulations Mom, Robin Réty, Stéphane Mocquet, Vincent Auguin, Daniel Int J Mol Sci Article Aquaporins (AQPs) constitute a wide and ancient protein family of transmembrane channels dedicated to the regulation of water exchange across biological membranes. In plants, higher numbers of AQP homologues have been conserved compared to other kingdoms of life such as in animals or in bacteria. As an illustration of this plant-specific functional diversity, plasma membrane intrinsic proteins (PIPs, i.e., a subfamily of plant AQPs) possess a long intracellular loop D, which can gate the channel by changing conformation as a function of the cellular environment. However, even though the closure of the AQP by loop D conformational changes is well described, the opening of the channel, on the other hand, is still misunderstood. Several studies have pointed to phosphorylation events as the trigger for the transition from closed- to open-channel states. Nonetheless, no clear answer has been obtained yet. Hence, in order to gain a more complete grasp of plant AQP regulation through this intracellular loop D gating, we investigated the opening of the channel in silico through molecular dynamics simulations of the crystallographic structure of Spinacia oleracea PIP2;1 (SoPIP2;1). Through this technique, we addressed the mechanistic details of these conformational changes, which eventually allowed us to propose a molecular mechanism for PIP functional regulation by loop D phosphorylation. More precisely, our results highlight the phosphorylation of loop D serine 188 as a trigger of SoPIP2;1 water channel opening. Finally, we discuss the significance of this result for the study of plant AQP functional diversity. MDPI 2023-09-07 /pmc/articles/PMC10531447/ /pubmed/37762101 http://dx.doi.org/10.3390/ijms241813798 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Mom, Robin
Réty, Stéphane
Mocquet, Vincent
Auguin, Daniel
Plant Aquaporin Gating Is Reversed by Phosphorylation on Intracellular Loop D—Evidence from Molecular Dynamics Simulations
title Plant Aquaporin Gating Is Reversed by Phosphorylation on Intracellular Loop D—Evidence from Molecular Dynamics Simulations
title_full Plant Aquaporin Gating Is Reversed by Phosphorylation on Intracellular Loop D—Evidence from Molecular Dynamics Simulations
title_fullStr Plant Aquaporin Gating Is Reversed by Phosphorylation on Intracellular Loop D—Evidence from Molecular Dynamics Simulations
title_full_unstemmed Plant Aquaporin Gating Is Reversed by Phosphorylation on Intracellular Loop D—Evidence from Molecular Dynamics Simulations
title_short Plant Aquaporin Gating Is Reversed by Phosphorylation on Intracellular Loop D—Evidence from Molecular Dynamics Simulations
title_sort plant aquaporin gating is reversed by phosphorylation on intracellular loop d—evidence from molecular dynamics simulations
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10531447/
https://www.ncbi.nlm.nih.gov/pubmed/37762101
http://dx.doi.org/10.3390/ijms241813798
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AT mocquetvincent plantaquaporingatingisreversedbyphosphorylationonintracellularloopdevidencefrommoleculardynamicssimulations
AT auguindaniel plantaquaporingatingisreversedbyphosphorylationonintracellularloopdevidencefrommoleculardynamicssimulations