Functional interaction of the SNARE protein NtSyp121 in Ca2+ channel gating, Ca2+ transients and ABA signalling of stomatal guard cells

Sokolovski, S., Hills, A., Gay, R. A. and Blatt, M. R. (2008) Functional interaction of the SNARE protein NtSyp121 in Ca2+ channel gating, Ca2+ transients and ABA signalling of stomatal guard cells. Molecular Plant, 1(2), pp. 347-358. (doi:10.1093/mp/ssm029)

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Publisher's URL: http://dx.doi.org/10.1093/mp/ssm029

Abstract

There is now growing evidence that membrane vesicle trafficking proteins, especially of the superfamily of SNAREs, are critical for cellular signalling in plants. Work from this laboratory first demonstrated that a soluble, inhibitory (dominant-negative) fragment of the SNARE NtSyp121 blocked K+ and Cl– channel responses to the stress-related hormone abscisic acid (ABA), but left open a question about functional impacts on signal intermediates, especially on Ca2+-mediated signalling events. Here, we report one mode of action for the SNARE mediated directly through alterations in Ca2+ channel gating and its consequent effects on cytosolic-free [Ca2+] ([Ca2+]i) elevation. We find that expressing the same inhibitory fragment of NtSyp121 blocks ABA-evoked stomatal closure, but only partially suppresses stomatal closure in the presence of the NO donor, SNAP, which promotes [Ca2+]i elevation independently of the plasma membrane Ca2+ channels. Consistent with these observations, Ca2+ channel gating at the plasma membrane is altered by the SNARE fragment in a manner effective in reducing the potential for triggering a rise in [Ca2+]i, and we show directly that its expression in vivo leads to a pronounced suppression of evoked [Ca2+]i transients. These observations offer primary evidence for the functional coupling of the SNARE with Ca2+ channels at the plant cell plasma membrane and, because [Ca2+]i plays a key role in the control of K+ and Cl– channel currents in guard cells, they underscore an important mechanism for SNARE integration with ion channel regulation during stomatal closure.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Hills, Mr Adrian and Blatt, Professor Michael and Sokolovski, Dr Sergei
Authors: Sokolovski, S., Hills, A., Gay, R. A., and Blatt, M. R.
College/School:College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
Journal Name:Molecular Plant
Publisher:Oxford University Press
ISSN:1674-2052
ISSN (Online):1752-9867

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
382911Signalling in plants - a new catch for a SNAREMichael BlattLeverhulme Trust (LEVERHULME)F/00 179/TInstitute of Molecular Cell and Systems Biology
305821Plasma Membrane CA2+ channels and signalling in Guard CellsMichael BlattBiotechnology and Biological Sciences Research Council (BBSRC)32/C09640Institute of Molecular Cell and Systems Biology
403581Co-operative gating interactions in the yeast TOK1 K+ channelMichael BlattBiotechnology and Biological Sciences Research Council (BBSRC)BB/D001528/1Institute of Molecular Cell and Systems Biology
378211Signalling and functional analysis of KCO1 channel interactions in ArabidopsisMichael BlattBiotechnology and Biological Sciences Research Council (BBSRC)BB/C500595/1Institute of Molecular Cell and Systems Biology