†These authors contributed equally to this work.
Protein phosphorylation is a prerequisite for intracellular Ca2+ release and ion channel control by nitric oxide and abscisic acid in guard cells
Article first published online: 20 JUL 2005
The Plant Journal
Volume 43, Issue 4, pages 520–529, August 2005
How to Cite
Sokolovski, S., Hills, A., Gay, R., Garcia-Mata, C., Lamattina, L. and Blatt, M. R. (2005), Protein phosphorylation is a prerequisite for intracellular Ca2+ release and ion channel control by nitric oxide and abscisic acid in guard cells. The Plant Journal, 43: 520–529. doi: 10.1111/j.1365-313X.2005.02471.x
- Issue published online: 20 JUL 2005
- Article first published online: 20 JUL 2005
- Received 2 April 2005; revised 17 May 2005; accepted 24 May 2005.
- K+ channel;
- Cl− channel;
- Vicia faba stomatal guard cell;
- oxidative stress;
- protein kinase;
- cytosolic-free Ca2+ concentration
Recent work has indicated that nitric oxide (NO) and its synthesis are important elements of signal cascades in plant–pathogen defence, and are a prerequisite for drought and abscisic acid (ABA) responses in Arabidopsis thaliana and Vicia faba guard cells. NO regulates inward-rectifying K+ channels and Cl− channels of Vicia guard cells via intracellular Ca2+ release. However, its integration with related signals, including the actions of serine–threonine protein kinases, is less well defined. We report here that the elevation of cytosolic-free [Ca2+] ([Ca2+]i) mediated by NO in guard cells is reversibly inhibited by the broad-range protein kinase antagonists staurosporine and K252A, but not by the tyrosine kinase antagonist genistein. The effects of kinase antagonism translate directly to a loss of NO-sensitivity of the inward-rectifying K+ channels and background (Cl− channel) current, and to a parallel loss in sensitivity of the K+ channels to ABA. These results demonstrate that NO-dependent signals can be modulated through protein phosphorylation upstream of intracellular Ca2+ release, and they implicate a target for protein kinase control in ABA signalling that feeds into NO-dependent Ca2+ release.