These authors equally contributed to this work.
Characterization of histidine-aspartate kinase HK1 and identification of histidine phosphotransfer proteins as potential partners in a Populus multistep phosphorelay
Version of Record online: 23 FEB 2013
© 2013 Scandinavian Plant Physiology Society
Volume 149, Issue 2, pages 188–199, October 2013
How to Cite
Héricourt, F., Chefdor, F., Bertheau, L., Tanigawa, M., Maeda, T., Guirimand, G., Courdavault, V., Larcher, M., Depierreux, C., Bénédetti, H., Morabito, D., Brignolas, F. and Carpin, S. (2013), Characterization of histidine-aspartate kinase HK1 and identification of histidine phosphotransfer proteins as potential partners in a Populus multistep phosphorelay. Physiologia Plantarum, 149: 188–199. doi: 10.1111/ppl.12024
- Issue online: 12 SEP 2013
- Version of Record online: 23 FEB 2013
- Accepted manuscript online: 18 JAN 2013 10:21AM EST
- Manuscript Accepted: 21 DEC 2012
- Manuscript Revised: 18 DEC 2012
- Manuscript Received: 2 OCT 2012
- The Conseil Régional Région Centre
- Conseil Général du Loiret and the Conseil Régional du Centre
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.