title: Characterization of histidine-aspartate kinase HK1 and identification of histidine phosphotransfer proteins as potential partners in a Populus multistep phosphorelay.
abstract: In poplar, we identified proteins homologous to yeast proteins involved in osmosensing multistep phosphorelay Sln1p-Ypd1p-Ssk1p. This finding led us to speculate that Populus cells could sense osmotic stress by a similar mechanism. This study focuses on first and second protagonists of this possible pathway: a histidine-aspartate kinase (HK1), putative osmosensor and histidine phosphotransfer proteins (HPt1 to 10), potential partners of this HK. Characterization of HK1 showed its ability to homodimerize in two-hybrid tests and to act as an osmosensor with a kinase activity in yeast, by functional complementation of sln1Δ sho1Δ strain. Moreover, in plant cells, plasma membrane localization of HK1 is shown. Further analysis on HPts allowed us to isolate seven new cDNAs, leading to a total of 10 different HPts identified in poplar. Interaction tests showed that almost all HPts can interact with HK1, but two of them exhibit stronger interactions, suggesting a preferential partnership in poplar. The importance of the phosphorylation status in these interactions has been investigated with two-hybrid tests carried out with mutated HK1 forms. Finally, in planta co-expression analysis of genes encoding these potential partners revealed that only three HPts are co-expressed with HK1 in different poplar organs. This result reinforces the hypothesis of a partnership between HK1 and these three preferential HPts in planta. Taken together, these results shed some light on proteins partnerships that could be involved in the osmosensing pathway in Populus.
authors: Université d'Orléans, UPRES EA 1207, Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), 45067, Orléans Cedex 2, France; INRA, USC1328, Arbres et Réponses aux Contraintes Hydriques et Environnementales (ARCHE), 45067, Orléans Cedex 2, France.
authors: François
authors: F
authors: Héricourt
authors: Françoise
authors: F
authors: Chefdor
authors: Lucie
authors: L
authors: Bertheau
authors: Mirai
authors: M
authors: Tanigawa
authors: Tatsuya
authors: T
authors: Maeda
authors: Grégory
authors: G
authors: Guirimand
authors: Vincent
authors: V
authors: Courdavault
authors: Mélanie
authors: M
authors: Larcher
authors: Christiane
authors: C
authors: Depierreux
authors: Hélène
authors: H
authors: Bénédetti
authors: Domenico
authors: D
authors: Morabito
authors: Franck
authors: F
authors: Brignolas
authors: Sabine
authors: S
authors: Carpin
mesh_terms: D000595:Amino Acid Sequence; D001222:Aspartate Kinase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D005816:Genetic Complementation Test; D006639:Histidine / Q000235:genetics / Q000378:metabolism*; D000071677:Histidine Kinase; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D010766:Phosphorylation; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D032107:Populus / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D011494:Protein Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D055503:Protein Multimerization; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D020798:Two-Hybrid System Techniques
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D010940:Plant Proteins; C459787:SHO1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D006639:Histidine; D011494:Protein Kinases; C102035:YPD1 protein, S cerevisiae; D000071677:Histidine Kinase; C083749:SLN1 protein, S cerevisiae; D001222:Aspartate Kinase