The Nicotiana tabacum plasma membrane aquaporin NtAQP1 is mercury-insensitive and permeable for glycerol.
A new aquaporin from Nicotiana tabacum (cv. Samsun) was characterized. It shares sequence homology to the Arabidopsis thaliana PIP1 protein family. By two-phase partitioning and immunoblot analysis, plasma membrane localization could be demonstrated. The corresponding mRNA is highly abundant in roots and flowers, while it is rarely expressed in leaves and stems. Functional expression in Xenopus oocytes revealed that NtAQP1 can mediate glycerol transport in addition to water flow. However, NtAQP1 is impermeable for Na+, K+ and Cl- ions. The water permeability and selectivity could not be modulated by addition of mercurials or the activity of cAMP-dependent protein kinases.
Julius-von-Sachs-Institut für Biowissenschaften, Molekulare Pflanzenphysiologie und Biophysik, Universität Würzburg, Germany.
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Biela
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Grote
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Otto
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Hoth
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Hedrich
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R
Kaldenhoff
D000818:Animals; D051398:Aquaporin 1; D020346:Aquaporins / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D001692:Biological Transport; D002463:Cell Membrane Permeability; D018076:DNA, Complementary / Q000235:genetics; D004553:Electric Conductivity; D005260:Female; D015723:Gene Library; D005990:Glycerol / Q000378:metabolism*; D008628:Mercury / Q000494:pharmacology; D008969:Molecular Sequence Data; D009865:Oocytes; D009997:Osmotic Pressure; D010940:Plant Proteins / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D010947:Plants, Toxic; D017422:Sequence Analysis, DNA; D014018:Tissue Distribution; D014026:Nicotiana / Q000235:genetics*; D014867:Water / Q000378:metabolism*; D014981:Xenopus
D020346:Aquaporins; D018076:DNA, Complementary; D010940:Plant Proteins; D014867:Water; D051398:Aquaporin 1; D008628:Mercury; D005990:Glycerol