Functional Divergence of Poplar Histidine-Aspartate Kinase HK1 Paralogs in Response to Osmotic Stress

Autor: François Héricourt, Françoise Chefdor, Inès Djeghdir, Mélanie Larcher, Florent Lafontaine, Vincent Courdavault, Daniel Auguin, Franck Coste, Christiane Depierreux, Mirai Tanigawa, Tatsuya Maeda, Gaëlle Glévarec, Sabine Carpin
Jazyk: angličtina
Rok vydání: 2016
Předmět:
Zdroj: International Journal of Molecular Sciences, Vol 17, Iss 12, p 2061 (2016)
Druh dokumentu: article
ISSN: 1422-0067
DOI: 10.3390/ijms17122061
Popis: Previous works have shown the existence of protein partnerships belonging to a MultiStep Phosphorelay (MSP) in Populus putatively 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. The HK1b expression analysis in different poplar organs revealed its co-expression with three HPts, 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 of HK1 gene duplication in poplar adaptation to drought stress.
Databáze: Directory of Open Access Journals