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Plasma membrane aquaporins in the motor cells of Samanea saman: diurnal and circadian regulation.

Moshelion, Menachem and Becker, Dirk and Biela, Alexander and Uehlein, Norbert and Hedrich, Rainer and Otto, Beate and Levi, Hadas and Moran, Nava and Kaldenhoff, Ralf (2002):
Plasma membrane aquaporins in the motor cells of Samanea saman: diurnal and circadian regulation.
In: The Plant cell, pp. 727-39, 14, (3), ISSN 1040-4651,
[Article]

Abstract

Leaf-moving organs, remarkable for the rhythmic volume changes of their motor cells, served as a model system in which to study the regulation of membrane water fluxes. Two plasma membrane intrinsic protein homolog genes, SsAQP1 and SsAQP2, were cloned from these organs and characterized as aquaporins in Xenopus laevis oocytes. Osmotic water permeability (P(f)) was 10 times higher in SsAQP2-expressing oocytes than in SsAQP1-expressing oocytes. SsAQP1 was found to be glycerol permeable, and SsAQP2 was inhibited by 0.5 mM HgCl(2) and by 1 mM phloretin. The aquaporin mRNA levels differed in their spatial distribution in the leaf and were regulated diurnally in phase with leaflet movements. Additionally, SsAQP2 transcription was under circadian control. The P(f) of motor cell protoplasts was regulated diurnally as well: the morning and/or evening P(f) increases were inhibited by 50 microM HgCl(2), by 2 mM cycloheximide, and by 250 microM phloretin to the noon P(f) level. Our results link SsAQP2 to the physiological function of rhythmic cell volume changes.

Item Type: Article
Erschienen: 2002
Creators: Moshelion, Menachem and Becker, Dirk and Biela, Alexander and Uehlein, Norbert and Hedrich, Rainer and Otto, Beate and Levi, Hadas and Moran, Nava and Kaldenhoff, Ralf
Title: Plasma membrane aquaporins in the motor cells of Samanea saman: diurnal and circadian regulation.
Language: English
Abstract:

Leaf-moving organs, remarkable for the rhythmic volume changes of their motor cells, served as a model system in which to study the regulation of membrane water fluxes. Two plasma membrane intrinsic protein homolog genes, SsAQP1 and SsAQP2, were cloned from these organs and characterized as aquaporins in Xenopus laevis oocytes. Osmotic water permeability (P(f)) was 10 times higher in SsAQP2-expressing oocytes than in SsAQP1-expressing oocytes. SsAQP1 was found to be glycerol permeable, and SsAQP2 was inhibited by 0.5 mM HgCl(2) and by 1 mM phloretin. The aquaporin mRNA levels differed in their spatial distribution in the leaf and were regulated diurnally in phase with leaflet movements. Additionally, SsAQP2 transcription was under circadian control. The P(f) of motor cell protoplasts was regulated diurnally as well: the morning and/or evening P(f) increases were inhibited by 50 microM HgCl(2), by 2 mM cycloheximide, and by 250 microM phloretin to the noon P(f) level. Our results link SsAQP2 to the physiological function of rhythmic cell volume changes.

Journal or Publication Title: The Plant cell
Volume: 14
Number: 3
Divisions: 10 Department of Biology > Applied Plant Sciences
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10 Department of Biology
Date Deposited: 31 Aug 2011 12:45
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