1. New Insight into HPts as Hubs in Poplar Cytokinin and Osmosensing Multistep Phosphorelays: Cytokinin Pathway Uses Specific HPts
- Author
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Mirai Tanigawa, Konstantinos Koudounas, Françoise Chefdor, Tatsuya Maeda, Gaëlle Glévarec, Christiane Depierreux, François Héricourt, Pamela Lemos Cruz, Frédéric Lamblin, Mélanie Larcher, Sabine Carpin, Vincent Courdavault, Inês Carqueijeiro, Laboratoire de Biologie des Ligneux et des Grandes Cultures (LBLGC), Institut National de la Recherche Agronomique (INRA)-Université d'Orléans (UO), Biomolécules et biotechnologies végétales (BBV EA 2106), Université de Tours (UT), Hamamatsu University School of Medicine, and Université de Tours
- Subjects
0106 biological sciences ,0301 basic medicine ,histidine-aspartate kinase ,HK ,HPt ,histidine phosphotransfer protein ,CK ,cytokinin ,OS ,osmosensing ,MSP ,multistep phosphorelay ,protéine de transfert ,[SDV]Life Sciences [q-bio] ,Plant Science ,populus ,01 natural sciences ,complex mixtures ,Article ,03 medical and health sciences ,Bimolecular fluorescence complementation ,Arabidopsis ,parasitic diseases ,cytokine ,Kinase activity ,Gene ,Transcription factor ,neoplasms ,Ecology, Evolution, Behavior and Systematics ,Vegetal Biology ,Ecology ,biology ,Kinase ,Chemistry ,fungi ,histidine kinase ,biology.organism_classification ,3. Good health ,Complementation ,030104 developmental biology ,voie de signalisation ,Biochemistry ,système phosphotransférase ,pression osmotique ,récepteur membranaire ,Signal transduction ,Biologie végétale ,010606 plant biology & botany - Abstract
We have previously identified proteins in poplar which belong to an osmosensing (OS) signaling pathway, called a multistep phosphorelay (MSP). The MSP comprises histidine-aspartate kinases (HK), which act as membrane receptors, histidine phosphotransfer (HPt) proteins, which act as phosphorelay proteins, and response regulators (RR), some of which act as transcription factors. In this study, we identified the HK proteins homologous to the Arabidopsis cytokinin (CK) receptors, which are first partners in the poplar cytokinin MSP, and focused on specificity of these two MSPs (CK and OS), which seem to share the same pool of HPt proteins. Firstly, we isolated five CK HKs from poplar which are homologous to Arabidopsis AHK2, AHK3, and AHK4, namely, HK2, HK3a, HK3b, HK4a, HK4b. These HKs were shown to be functional kinases, as observed in a functional complementation of a yeast HK deleted strain. Moreover, one of these HKs, HK4a, was shown to have kinase activity dependent on the presence of CK. Exhaustive interaction tests between these five CK HKs and the 10 HPts characterized in poplar were performed using two-hybrid and BiFC experiments. The resulting partnership was compared to that previously identified between putative osmosensors HK1a/1b and HPt proteins. Finally, in planta coexpression analysis of genes encoding these potential partners revealed that almost all HPts are coexpressed with CK HKs in four different poplar organs. Overall, these results allowed us to unravel the common and specific partnerships existing between OS and CK MSP in Populus.
- Published
- 2019