The grapevine tonoplast aquaporin TIP2;1 is a pressure gated water channel
2014
Leitão, Luís | Prista, Catarina | Loureiro-Dias, Maria C. | Moura, Teresa F. | Soveral, Graça | Institut d'Ecologie et des Sciences de l'Environnement de Paris ; Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Recherche pour le Développement (IRD [France-Ouest])-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Ecole Normale Supérieure Paris-Saclay (ENS Paris Saclay) | Universidade de Lisboa = University of Lisbon = Université de Lisbonne (ULISBOA)
International audience
显示更多 [+] 显示较少 [-]英语. In plants, the vacuole is a multifunctional organelle with an important role in the maintenance of the intracellular space. Tonoplast membranes are highly permeable to water due to their content in aquaporins TIPs (Tonoplast Intrinsic Proteins) that allow the rapid water influx creating an internal turgor pressure responsible for cell expansion, elongation and shape. The aim of the present study was to evaluate if the grapevine Vitis vinifera TIP2;1 would operate as a possible volume regulator gated by membrane surface tension. For that, the wild type VvTIP2;1 and a non-functional mutated form were heterologous expressed in yeast. Using an experimental strategy in which cells are incubated in external media that induce an increase in internal hydrostatic pressure and consequently membrane surface tension, we were able to compare the osmotic permeability (P-f) and the activation energy for water transport (E-a) of yeast strains expressing the functional and a non-functional TIP2;1. We found P-f and E-a dependence on internal turgor pressure only for the strain harboring the functional aquaporin indicating that TIP2;1 activity is regulated by membrane tension changing from an open to a closed state in an internal pressure dependent manner. This turgor dependent gating of TIP2;1 might be a mechanism to regulate vacuolar size and shape in plants withstanding hostile drought conditions such as grapevine.
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