Plant and Cell Physiology Advance Access published online on January 24, 2007
Plant and Cell Physiology, doi:10.1093/pcp/pcm010
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Polyamines as physiological regulators of 14-3-3 interaction with the plant plasma membrane H+-ATPase
Department of Biology, University of Rome "Tor Vergata", via della Ricerca Scientifica, 00133 Rome, Italy.
Corresponding author Patrizia Aducci, Department of Biology, University of Rome "Tor Vergata", via della Ricerca Scientifica, 00133 Rome, Italy. Tel.: +39-06-72594082; Fax: +39-06-2023500. E-mail: Aducci{at}uniroma2.it
| Abstract |
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Polyamines are abundant polycationic compounds involved in many plant physiological processes such as cell division, dormancy breaking, plant morphogenesis and response to environmental stresses.
In this study we investigated the possible role of these polycations in modulating the association of 14-3-3 proteins with the H+-ATPase. In vivo experiments demonstrate that, among the different polyamines, spermine brings about two fold stimulation of the H+-ATPase activity and this effect is due to an increasing of 14-3-3 levels associated with the enzyme. In vivo administration of polyamines synthesis inhibitors causes a small but statistically significant decrease of the H+-ATPase phosphohydrolitic activity, demonstrating a physiological role of the polyamines in regulating the enzyme activity. Spermine stimulates the activity of the H+-ATPase AHA1 expressed in yeast, in the presence of exogenous 14-3-3 proteins, with a calculated S50 of 70 µM. Moreover, spermine enhances the in vitro interaction of 14-3-3 proteins with the H+-ATPase and notably induces 14-3-3 association with the unphosphorylated C-terminal domain of the proton pump. Comparison of spermine with Mg2+, necessary for binding of 14-3-3s to different target proteins, shows that polyamine effect is stronger and additive to that of the divalent cation.
Keywords: H+-ATPase - polyamines - 14-3-3 proteins - Zea mays
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S. Visconti, L. Camoni, M. Marra, and P. Aducci Role of the 14-3-3 C-Terminal Region in the Interaction with the Plasma Membrane H+-ATPase Plant Cell Physiol., December 1, 2008; 49(12): 1887 - 1897. [Abstract] [Full Text] [PDF] |
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