Protein kinase CK2 modulates developmental functions of the abscisic acid responsive protein Rab17 from maize
AUTOR(ES)
Riera, Marta
FONTE
National Academy of Sciences
RESUMO
The maize abscisic acid responsive protein Rab17 is a highly phosphorylated late embryogenesis abundant protein involved in plant responses to stress. In this study, we provide evidence of the importance of Rab17 phosphorylation by protein kinase CK2 in growth-related processes under stress conditions. We show the specific interaction of Rab17 with the CK2 regulatory subunits CK2β-1 and CK2β-3, and that these interactions do not depend on the phosphorylation state of Rab17. Live-cell fluorescence imaging of both CK2 and Rab17 indicates that the intracellular dynamics of Rab17 are regulated by CK2 phosphorylation. We found both CK2β subunits and Rab17 distributed over the cytoplasm and nucleus. By contrast, catalytic CK2α subunits and a Rab17 mutant protein (mRab17) that is not a substrate for CK2 phosphorylation remain accumulated in the nucleoli. A dual-color image shows that the CK2 holoenzyme accumulates mainly in the nucleus. The importance of Rab17 phosphorylation in vivo was assessed in transgenic plants. The overexpression of Rab17, but not mRab17, arrests the process of seed germination under osmotic stress conditions. Thus, the role of Rab17 in growth processes is mediated through its phosphorylation by protein kinase CK2.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=470767Documentos Relacionados
- The maize abscisic acid-responsive protein Rab17 is located in the nucleus and interacts with nuclear localization signals.
- Crystal structure of human protein kinase CK2: insights into basic properties of the CK2 holoenzyme
- Protein kinase CK2 and protein kinase D are associated with the COP9 signalosome
- Structural basis of regulation and substrate specificity of protein kinase CK2 deduced from the modeling of protein-protein interactions
- Live-Cell Fluorescence Imaging Reveals the Dynamics of Protein Kinase CK2 Individual Subunits