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Aquaporin tetramer composition modifies the function of tobacco aquaporins.

Otto, Beate and Uehlein, Norbert and Sdorra, Sven and Fischer, Matthias and Ayaz, Muhammad and Belastegui-Macadam, Xana and Heckwolf, Marlies and Lachnit, Magdalena and Pede, Nadine and Priem, Nadine and Reinhard, André and Siegfart, Sven and Urban, Michael and Kaldenhoff, Ralf (2010):
Aquaporin tetramer composition modifies the function of tobacco aquaporins.
In: The Journal of biological chemistry, pp. 31253-60, 285, (41), ISSN 1083-351X,
[Article]

Abstract

Heterologous expression in yeast cells revealed that NtAQP1, a member of the so-called PIP1 aquaporin subfamily, did not display increased water transport activity in comparison with controls. Instead, an increased CO(2)-triggered intracellular acidification was observed. NtPIP2;1, which belongs to the PIP2 subfamily of plant aquaporins, behaved as a true aquaporin but lacked a CO(2)-related function. Results from split YFP experiments, protein chromatography, and gel electrophoresis indicated that the proteins form heterotetramers when coexpressed in yeast. Tetramer composition had effects on transport activity as demonstrated by analysis of artificial heterotetramers with a defined proportion of NtAQP1 to NtPIP2;1. A single NtPIP2;1 aquaporin in a tetramer was sufficient to significantly increase the water permeability of the respective yeast cells. With regard to CO(2)-triggered intracellular acidification, a cooperative effect was observed, where maximum rates were measured when the tetramer consisted of NtAQP1 aquaporins only. The results confirm the model of an aquaporin monomer as a functional unit for water transport and suggest that, for CO(2)-related transport processes, a structure built up by the tetramer is the basis of this function.

Item Type: Article
Erschienen: 2010
Creators: Otto, Beate and Uehlein, Norbert and Sdorra, Sven and Fischer, Matthias and Ayaz, Muhammad and Belastegui-Macadam, Xana and Heckwolf, Marlies and Lachnit, Magdalena and Pede, Nadine and Priem, Nadine and Reinhard, André and Siegfart, Sven and Urban, Michael and Kaldenhoff, Ralf
Title: Aquaporin tetramer composition modifies the function of tobacco aquaporins.
Language: English
Abstract:

Heterologous expression in yeast cells revealed that NtAQP1, a member of the so-called PIP1 aquaporin subfamily, did not display increased water transport activity in comparison with controls. Instead, an increased CO(2)-triggered intracellular acidification was observed. NtPIP2;1, which belongs to the PIP2 subfamily of plant aquaporins, behaved as a true aquaporin but lacked a CO(2)-related function. Results from split YFP experiments, protein chromatography, and gel electrophoresis indicated that the proteins form heterotetramers when coexpressed in yeast. Tetramer composition had effects on transport activity as demonstrated by analysis of artificial heterotetramers with a defined proportion of NtAQP1 to NtPIP2;1. A single NtPIP2;1 aquaporin in a tetramer was sufficient to significantly increase the water permeability of the respective yeast cells. With regard to CO(2)-triggered intracellular acidification, a cooperative effect was observed, where maximum rates were measured when the tetramer consisted of NtAQP1 aquaporins only. The results confirm the model of an aquaporin monomer as a functional unit for water transport and suggest that, for CO(2)-related transport processes, a structure built up by the tetramer is the basis of this function.

Journal or Publication Title: The Journal of biological chemistry
Volume: 285
Number: 41
Divisions: 10 Department of Biology > Applied Plant Sciences
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10 Department of Biology
Date Deposited: 31 Aug 2011 12:00
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