Laohavisit, A., Shang, Z., Rubio, L., Cuin, T. A., Very, A.-A., Wang, A., Mortimer, J. C., Macpherson, N., Coxon, K. M., Battey, N. H., Brownlee, C., Park, O. K., Sentenac, H., Shabala, S., Webb, A. A. R. and Davies, J. M.
Arabidopsis annexin1 mediates the radical-activated plasma membrane Ca2+ - and K+ -permeable conductance in root cells.
The Plant Cell, 24 (4).
To link to this article DOI: 10.1105/tpc.112.097881
Plant cell growth and stress signaling require Ca2+ influx through plasma membrane transport proteins that are regulated by
reactive oxygen species. In root cell growth, adaptation to salinity stress, and stomatal closure, such proteins operate
downstream of the plasma membrane NADPH oxidases that produce extracellular superoxide anion, a reactive oxygen
species that is readily converted to extracellular hydrogen peroxide and hydroxyl radicals, OH_. In root cells, extracellular OH_ activates a plasma membrane Ca2+-permeable conductance that permits Ca2+ influx. In Arabidopsis thaliana, distribution of
this conductance resembles that of annexin1 (ANN1). Annexins are membrane binding proteins that can form Ca2+-permeable
conductances in vitro. Here, the Arabidopsis loss-of-function mutant for annexin1 (Atann1) was found to lack the root hair and
epidermal OH_-activated Ca2+- and K+-permeable conductance. This manifests in both impaired root cell growth and ability to
elevate root cell cytosolic free Ca2+ in response to OH_. An OH_-activated Ca2+ conductance is reconstituted by recombinant
ANN1 in planar lipid bilayers. ANN1 therefore presents as a novel Ca2+-permeable transporter providing a molecular link
between reactive oxygen species and cytosolic Ca2+ in plants.
|Date Deposited:||02 May 2012 13:16|
|Last Modified:||24 Jun 2014 16:52|
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