title: Functional Divergence of Poplar Histidine-Aspartate Kinase HK1 Paralogs in Response to Osmotic Stress.
abstract: Previous works have shown the existence of protein partnerships belonging to a MultiStep Phosphorelay (MSP) inPopulusputatively involved in osmosensing. This study is focused on the identification of a histidine-aspartate kinase, HK1b, paralog of HK1a. The characterization of HK1b showed its ability to homo- and hetero-dimerize and to interact with a few Histidine-containing Phosphotransfer (HPt) proteins, suggesting a preferential partnership in poplar MSP linked to drought perception. Furthermore, determinants for interaction specificity between HK1a/1b and HPts were studied by mutagenesis analysis, identifying amino acids involved in this specificity. TheHK1bexpression analysis in different poplar organs revealed its co-expression with threeHPts, reinforcing the hypothesis of partnership participation in the MSP in planta. Moreover, HK1b was shown to act as an osmosensor with kinase activity in a functional complementation assay of an osmosensor deficient yeast strain. These results revealed that HK1b showed a different behaviour for canonical phosphorylation of histidine and aspartate residues. These phosphorylation modularities of canonical amino acids could explain the improved osmosensor performances observed in yeast. As conserved duplicates reflect the selective pressures imposed by the environmental requirements on the species, our results emphasize the importance ofHK1gene duplication in poplar adaptation to drought stress.
authors.affiliation: Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), Université d'Orléans, INRA, USC1328, 45067 Orléans, France. francois.hericourt@univ-orleans.fr.
authors.forename: François
authors.initials: F
authors.lastname: Héricourt
authors.affiliation: Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), Université d'Orléans, INRA, USC1328, 45067 Orléans, France. francoise.chefdor@univ-orleans.fr.
authors.forename: Françoise
authors.initials: F
authors.lastname: Chefdor
authors.affiliation: Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), Université d'Orléans, INRA, USC1328, 45067 Orléans, France. ines.djeghdir@univ-orleans.fr.
authors.forename: Inès
authors.initials: I
authors.lastname: Djeghdir
authors.affiliation: Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), Université d'Orléans, INRA, USC1328, 45067 Orléans, France. melanie.larcher@univ-orleans.fr.
authors.forename: Mélanie
authors.initials: M
authors.lastname: Larcher
authors.affiliation: Biomolécules et Biotechnologies Végétales (BBV), EA 2106, Université François Rabelais de Tours, 31 avenue Monge, 37200 Tours, France. fllafontaine@univ-tours.fr.
authors.forename: Florent
authors.initials: F
authors.lastname: Lafontaine
authors.affiliation: Biomolécules et Biotechnologies Végétales (BBV), EA 2106, Université François Rabelais de Tours, 31 avenue Monge, 37200 Tours, France. vincent.courdavault@univ-tours.fr.
authors.forename: Vincent
authors.initials: V
authors.lastname: Courdavault
authors.affiliation: Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), Université d'Orléans, INRA, USC1328, 45067 Orléans, France. daniel.auguin@univ-orleans.fr.
authors.forename: Daniel
authors.initials: D
authors.lastname: Auguin
authors.affiliation: Centre de Biophysique Moléculaire (CBM), CNRS, 45071 Orléans, France. franck.coste@cnrs-orleans.fr.
authors.forename: Franck
authors.initials: F
authors.lastname: Coste
authors.affiliation: Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), Université d'Orléans, INRA, USC1328, 45067 Orléans, France. christiane.depierreux@univ-orleans.fr.
authors.forename: Christiane
authors.initials: C
authors.lastname: Depierreux
authors.affiliation: Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan. las17mirai@yahoo.co.jp.
authors.forename: Mirai
authors.initials: M
authors.lastname: Tanigawa
authors.affiliation: Institute of Molecular and Cellular Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan. maeda@iam.u-tokyo.ac.jp.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Maeda
authors.affiliation: Biomolécules et Biotechnologies Végétales (BBV), EA 2106, Université François Rabelais de Tours, 31 avenue Monge, 37200 Tours, France. gaelle.glevarec@univ-tours.fr.
authors.forename: Gaëlle
authors.initials: G
authors.lastname: Glévarec
authors.affiliation: Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), Université d'Orléans, INRA, USC1328, 45067 Orléans, France. sabine.carpin@univ-orleans.fr.
authors.forename: Sabine
authors.initials: S
authors.lastname: Carpin
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D001224:Aspartic Acid / Q000378:metabolism*; D020440:Gene Duplication; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D000071677:Histidine Kinase; D050505:Mutant Proteins / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D009997:Osmotic Pressure; D010802:Phylogeny; D032107:Populus / Q000201:enzymology* / Q000235:genetics; D011485:Protein Binding; D055503:Protein Multimerization; D015203:Reproducibility of Results; D017386:Sequence Homology, Amino Acid; D013312:Stress, Physiological / Q000235:genetics; D013379:Substrate Specificity; D020798:Two-Hybrid System Techniques
chemical_list: D000596:Amino Acids; D050505:Mutant Proteins; D001224:Aspartic Acid; D000071677:Histidine Kinase
keywords: Populus; drought signaling; histidine-aspartate kinase (HK); histidine-containing phosphotransfer protein (HPt); multistep phosphorelay (MSP); osmosensing