title: The calcium-dependent protein kinase CPK7 acts on root hydraulic conductivity.
abstract: The hydraulic conductivity of plant roots (Lp(r)) is determined in large part by the activity of aquaporins. Mechanisms occurring at the post-translational level, in particular phosphorylation of aquaporins of the plasma membrane intrinsic protein 2 (PIP2) subfamily, are thought to be of critical importance for regulating root water transport. However, knowledge of protein kinases and phosphatases acting on aquaporin function is still scarce. In the present work, we investigated the Lp(r) of knockout Arabidopsis plants for four Ca(2+)-dependent protein kinases. cpk7 plants showed a 30% increase in Lp(r) because of a higher aquaporin activity. A quantitative proteomic analysis of wild-type and cpk7 plants revealed that PIP gene expression and PIP protein quantity were not correlated and that CPK7 has no effect on PIP2 phosphorylation. In contrast, CPK7 exerts a negative control on the cellular abundance of PIP1s, which likely accounts for the higher Lp(r) of cpk7. In addition, this study revealed that the cellular amount of a few additional proteins including membrane transporters is controlled by CPK7. The overall work provides evidence for CPK7-dependent stability of specific membrane proteins.
authors.affiliation: Biochimie et Physiologie Moléculaire des Plantes, INRA/CNRS/SupAgro/UM2, UMR 5004, 2 Place Viala, Montpellier Cedex 1, 34060, France.
authors.forename: Guowei
authors.initials: G
authors.lastname: Li
authors.affiliation: Saclay Plant Sciences, Institut des Sciences du Végétal, UPR2355, 1 Avenue de la Terrasse, Gif-sur-Yvette Cedex, 91198, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Boudsocq
authors.affiliation: Laboratoire de Protéomique Fonctionnelle, UR1199, 1 Place Viala, Montpellier Cedex 1, 34060, France.
authors.forename: Sonia
authors.initials: S
authors.lastname: Hem
authors.affiliation: Laboratoire de Protéomique Fonctionnelle, UR1199, 1 Place Viala, Montpellier Cedex 1, 34060, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Vialaret
authors.affiliation: Laboratoire de Protéomique Fonctionnelle, UR1199, 1 Place Viala, Montpellier Cedex 1, 34060, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Rossignol
authors.affiliation: Biochimie et Physiologie Moléculaire des Plantes, INRA/CNRS/SupAgro/UM2, UMR 5004, 2 Place Viala, Montpellier Cedex 1, 34060, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Maurel
authors.affiliation: Biochimie et Physiologie Moléculaire des Plantes, INRA/CNRS/SupAgro/UM2, UMR 5004, 2 Place Viala, Montpellier Cedex 1, 34060, France.
authors.forename: Véronique
authors.initials: V
authors.lastname: Santoni
mesh_terms: D020346:Aquaporins / Q000235:genetics / Q000378:metabolism*; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport; D018506:Gene Expression Regulation, Plant; D055786:Gene Knockout Techniques; D016254:Mutagenesis, Insertional; D010766:Phosphorylation; D018517:Plant Roots / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D018526:Plant Transpiration / Q000502:physiology; D030821:Plants, Genetically Modified; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D040901:Proteomics; D014867:Water / Q000502:physiology; D017871:Calcium-Calmodulin-Dependent Protein Kinases
chemical_list: D020346:Aquaporins; D029681:Arabidopsis Proteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D014867:Water; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C000607901:CPK7 protein, Arabidopsis
keywords: CDPK; PIP; aquaporin; phosphorylation; quantitative proteomics; root water transport