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Reversible inactivation of K+ channels of Vicia stomatal guard cells following the photolysis of caged inositol 1,4,5-trisphosphate.

Blatt, M. R. and Thiel, Gerhard and Trentham, D. R. (1990):
Reversible inactivation of K+ channels of Vicia stomatal guard cells following the photolysis of caged inositol 1,4,5-trisphosphate.
In: Nature, 346 (6286), pp. 766-9, ISSN 0028-0836,
[Article]

Abstract

RECENT investigations suggest that cytoplasmic D-myo-inositol 1,4,5-trisphosphate (InsP3) functions as a second messenger in plants, as in animals, coupling environmental and other stimuli to intracellular Ca2+ release. Cytoplasmic levels of InsP3 and the turnover of several probable precursors in plants are affected by physiological stimuli--including light, osmotic stress and the phytohormone indoleacetic acid--and InsP3 activates Ca2+ channels and Ca2+ flux across plant vacuolar and microsomal membranes. Complementary data also link changes in cytoplasmic free Ca2+ to several physiological responses, notably in guard cells which regulate gas exchange through the stomatal pores of higher plant leaves. Recent evidence indicates that guard cell K+ channels and, hence, K+ flux for stomatal movements may be controlled by cytoplasmic Ca2+. So far, however, direct evidence of a role for InsP3 in signalling in plants has remained elusive. Here we report that InsP3 released from an inactive, photolabile precursor, the P5-1-(2-nitrophenyl)ethyl ester of InsP3 (caged InsP3) reversibly inactivates K+ channels thought to mediate K+ uptake by guard cells from Vicia faba L. while simultaneously activating an apparently time-independent, inward current to depolarize the membrane potential and promote K+ efflux through a second class of K+ channels. The data are consistent with a transient rise in cytoplasmic free Ca2+ and demonstrate that intact guard cells are competent to use InsP3 in signal cascades controlling ion flux through K+ channels.

Item Type: Article
Erschienen: 1990
Creators: Blatt, M. R. and Thiel, Gerhard and Trentham, D. R.
Title: Reversible inactivation of K+ channels of Vicia stomatal guard cells following the photolysis of caged inositol 1,4,5-trisphosphate.
Language: English
Abstract:

RECENT investigations suggest that cytoplasmic D-myo-inositol 1,4,5-trisphosphate (InsP3) functions as a second messenger in plants, as in animals, coupling environmental and other stimuli to intracellular Ca2+ release. Cytoplasmic levels of InsP3 and the turnover of several probable precursors in plants are affected by physiological stimuli--including light, osmotic stress and the phytohormone indoleacetic acid--and InsP3 activates Ca2+ channels and Ca2+ flux across plant vacuolar and microsomal membranes. Complementary data also link changes in cytoplasmic free Ca2+ to several physiological responses, notably in guard cells which regulate gas exchange through the stomatal pores of higher plant leaves. Recent evidence indicates that guard cell K+ channels and, hence, K+ flux for stomatal movements may be controlled by cytoplasmic Ca2+. So far, however, direct evidence of a role for InsP3 in signalling in plants has remained elusive. Here we report that InsP3 released from an inactive, photolabile precursor, the P5-1-(2-nitrophenyl)ethyl ester of InsP3 (caged InsP3) reversibly inactivates K+ channels thought to mediate K+ uptake by guard cells from Vicia faba L. while simultaneously activating an apparently time-independent, inward current to depolarize the membrane potential and promote K+ efflux through a second class of K+ channels. The data are consistent with a transient rise in cytoplasmic free Ca2+ and demonstrate that intact guard cells are competent to use InsP3 in signal cascades controlling ion flux through K+ channels.

Journal or Publication Title: Nature
Volume: 346
Number: 6286
Divisions: 10 Department of Biology > Plant Membrane Biophysics
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10 Department of Biology
Date Deposited: 22 Jun 2011 12:00
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