The water permeability of Arabidopsis plasma membrane is regulated by divalent cations and pH

Authors

  • Patricia Gerbeau,

    1. 1 Biochimie et Physiologie Moléculaire des Plantes, Agro-M/INRA/CNRS/UM2 , 2 place Viala, F-34060 Montpellier Cedex, France.2Institut des Sciences Végétales, CNRS, F-91198 Gif-sur-Yvette Cedex, France.3Laboratorio de Biomembranas, Depto de Fisiología, Fac. de Medicina, Universidad de Buenos Aires, Paraguay 2155 Piso 7, 1121 Buenos Aires, Argentina.4Lehrstuhl für Pflanzenökologie, Universität Bayreuth, Universitätstrasse 30, D-95440 Bayreuth, Germany.5Service de Biologie Cellulaire, Département de Biologie Cellulaire et Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France.
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      † Present address: Department of Molecular Biology, University of Geneva, 30 Quai Ernest Ansermet, 1211 Geneva 4, Switzerland.
  • 1,2, Gabriela Amodeo,

    1. 1 Biochimie et Physiologie Moléculaire des Plantes, Agro-M/INRA/CNRS/UM2 , 2 place Viala, F-34060 Montpellier Cedex, France.2Institut des Sciences Végétales, CNRS, F-91198 Gif-sur-Yvette Cedex, France.3Laboratorio de Biomembranas, Depto de Fisiología, Fac. de Medicina, Universidad de Buenos Aires, Paraguay 2155 Piso 7, 1121 Buenos Aires, Argentina.4Lehrstuhl für Pflanzenökologie, Universität Bayreuth, Universitätstrasse 30, D-95440 Bayreuth, Germany.5Service de Biologie Cellulaire, Département de Biologie Cellulaire et Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France.
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  • 2,3 Tobias Henzler,

    1. 1 Biochimie et Physiologie Moléculaire des Plantes, Agro-M/INRA/CNRS/UM2 , 2 place Viala, F-34060 Montpellier Cedex, France.2Institut des Sciences Végétales, CNRS, F-91198 Gif-sur-Yvette Cedex, France.3Laboratorio de Biomembranas, Depto de Fisiología, Fac. de Medicina, Universidad de Buenos Aires, Paraguay 2155 Piso 7, 1121 Buenos Aires, Argentina.4Lehrstuhl für Pflanzenökologie, Universität Bayreuth, Universitätstrasse 30, D-95440 Bayreuth, Germany.5Service de Biologie Cellulaire, Département de Biologie Cellulaire et Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France.
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  • 4 Véronique Santoni,

    1. 1 Biochimie et Physiologie Moléculaire des Plantes, Agro-M/INRA/CNRS/UM2 , 2 place Viala, F-34060 Montpellier Cedex, France.2Institut des Sciences Végétales, CNRS, F-91198 Gif-sur-Yvette Cedex, France.3Laboratorio de Biomembranas, Depto de Fisiología, Fac. de Medicina, Universidad de Buenos Aires, Paraguay 2155 Piso 7, 1121 Buenos Aires, Argentina.4Lehrstuhl für Pflanzenökologie, Universität Bayreuth, Universitätstrasse 30, D-95440 Bayreuth, Germany.5Service de Biologie Cellulaire, Département de Biologie Cellulaire et Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France.
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  • 1 Pierre Ripoche,

    1. 1 Biochimie et Physiologie Moléculaire des Plantes, Agro-M/INRA/CNRS/UM2 , 2 place Viala, F-34060 Montpellier Cedex, France.2Institut des Sciences Végétales, CNRS, F-91198 Gif-sur-Yvette Cedex, France.3Laboratorio de Biomembranas, Depto de Fisiología, Fac. de Medicina, Universidad de Buenos Aires, Paraguay 2155 Piso 7, 1121 Buenos Aires, Argentina.4Lehrstuhl für Pflanzenökologie, Universität Bayreuth, Universitätstrasse 30, D-95440 Bayreuth, Germany.5Service de Biologie Cellulaire, Département de Biologie Cellulaire et Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France.
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  • and 5 Christophe Maurel 1,2,

    Corresponding author
    1. 1 Biochimie et Physiologie Moléculaire des Plantes, Agro-M/INRA/CNRS/UM2 , 2 place Viala, F-34060 Montpellier Cedex, France.2Institut des Sciences Végétales, CNRS, F-91198 Gif-sur-Yvette Cedex, France.3Laboratorio de Biomembranas, Depto de Fisiología, Fac. de Medicina, Universidad de Buenos Aires, Paraguay 2155 Piso 7, 1121 Buenos Aires, Argentina.4Lehrstuhl für Pflanzenökologie, Universität Bayreuth, Universitätstrasse 30, D-95440 Bayreuth, Germany.5Service de Biologie Cellulaire, Département de Biologie Cellulaire et Moléculaire, CEA/Saclay, F-91191 Gif-sur-Yvette Cedex, France.
      *For correspondence (fax + 334 6752 5737; e-mail maurel@ensam.inra.fr).
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*For correspondence (fax + 334 6752 5737; e-mail maurel@ensam.inra.fr).
† Present address: Department of Molecular Biology, University of Geneva, 30 Quai Ernest Ansermet, 1211 Geneva 4, Switzerland.

Summary

Mechanisms that regulate water channels in the plant plasma membrane (PM) were investigated in Arabidopsis suspension cells. Cell hydraulic conductivity was measured with a cell pressure probe and was reduced 4-fold as compared to control values when calcium was added in the pipette and in bathing solution. To assess the significance of these effects in vitro, PM vesicles were isolated by aqueous two-phase partitioning and their water transport properties were characterized by stopped-flow spectrophotometry. Membrane vesicles isolated in standard conditions exhibited reduced water permeability (Pf) together with a lack of active water channels. In contrast, when prepared in the presence of chelators of divalent cations, PM vesicles showed a 2.3-fold higher Pf and active water channels. Furthermore, equilibration of purified PM vesicles with divalent cations reduced their Pf and water channel activity down to the basal level of membranes isolated in standard conditions. Ca2+ was the most efficient with a half-inhibition of Pf at 50–100 µm free Ca2+. Water transport in purified PM vesicles was also reversibly blocked by H+, with a half-inhibition of Pf at pH 7.2–7.5. Thus, both Ca2+ and H+ contribute to a membrane-delimited switch from active to inactive water channels that may allow coupling of water transport to cell signalling and metabolism.

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