Novel Regulation of Aquaporins during Osmotic Stress

Vera-Estrella, Rosario; Barkla, Bronwyn J.; Bohnert, Hans J.; Pantoja, Omar

doi:10.1104/pp.104.044891

Cited by 185 publications

(152 citation statements)

References 61 publications

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“…pollen. In animals, regulatory cycling between membranes is well documented for several aquaporins [24], whereas in plants, TIP relocalization has been proposed as a regulatory mechanism [25]. Therefore it is possible that TIP relocalization, if it occurs, would depend on specifically hydrodynamic signals that direct pollen tube growth.…”

Section: Discussionmentioning

confidence: 99%

AtTIP1;3 and AtTIP5;1, the only highly expressed Arabidopsis pollen‐specific aquaporins, transport water and urea

et al. 2008

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Pollination includes processes where water and/or solute movements must be finely regulated, suggesting participation of aquaporins. Using information available from different transcriptional profilings of Arabidopsis thaliana mature pollen, we showed that the only aquaporins that are selectively and highly expressed in mature pollen are two TIPs: AtTIP1;3 and AtTIP5;1. Pollen exhibited a lower number and more exclusive type of aquaporin expressed genes when compared to other single cell transcriptional profilings. When characterized using Xenopus oocyte swelling assays, AtTIP1;3 and AtTIP5;1 showed intermediate water permeabilities. Although they displayed neither glycerol nor boric acid permeability they both transported urea. In conclusion, these results suggest a function for AtTIP1;3 and AtTIP5;1 as specific water and urea channels in Arabidopsis pollen.

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Section: Discussionmentioning

confidence: 99%

AtTIP1;3 and AtTIP5;1, the only highly expressed Arabidopsis pollen‐specific aquaporins, transport water and urea

et al. 2008

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“…Pellets were air dried, resuspended with sample buffer (2.5% SDS), and heated at 608C for 2 min before loading (15 mg of protein per lane) onto 10% (w/v) linear acrylamide extra wide mini-gels (Scie-Plas). After electrophoresis, SDS-PAGE separated proteins were either fixed and stained with Coomassie Brilliant Blue R 250 or electrophoretically transferred onto nitrocellulose membranes (ECL; GE Lifesciences) for immunoblot analysis, as previously described (Vera-Estrella et al, 2004). Digital images were captured using a Hewlett Packard flatbed scanner (Scan Jet 8250).…”

Section: Sds-page Staining and Immunoblottingmentioning

confidence: 99%

“…In both salt-tolerant halophytes and salt-sensitive glycophytes, sodium regulates the expression at the transcript and protein levels for the tonoplast NHXs (Shi and Zhu, 2002;Yokoi et al, 2002) and different subunits of the V-ATPase Tsiantis et al, 1996;Dietz et al, 2001;Vera-Estrella et al, 2005). In addition, their transport activity has been shown to increase under salt stress (Reuveni et al, 1990;Barkla et al, 1995;Qiu et al, 2004;Vera-Estrella et al, 2004). In Arabidopsis thaliana, mutants of NHX family members displayed enhanced salt sensitivity (Shi et al, 2000;Apse et al, 2003), as do mutants in subunits of the V-ATPase.…”

Section: Introductionmentioning

confidence: 99%

Quantitative Proteomics of the Tonoplast Reveals a Role for Glycolytic Enzymes in Salt Tolerance

et al. 2009

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To examine the role of the tonoplast in plant salt tolerance and identify proteins involved in the regulation of transporters for vacuolar Na + sequestration, we exploited a targeted quantitative proteomics approach. Two-dimensional differential in-gel electrophoresis analysis of free flow zonal electrophoresis separated tonoplast fractions from control, and salt-treated Mesembryanthemum crystallinum plants revealed the membrane association of glycolytic enzymes aldolase and enolase, along with subunits of the vacuolar H + -ATPase V-ATPase. Protein blot analysis confirmed coordinated salt regulation of these proteins, and chaotrope treatment indicated a strong tonoplast association. Reciprocal coimmunoprecipitation studies revealed that the glycolytic enzymes interacted with the V-ATPase subunit B VHA-B, and aldolase was shown to stimulate V-ATPase activity in vitro by increasing the affinity for ATP. To investigate a physiological role for this association, the Arabidopsis thaliana cytoplasmic enolase mutant, los2, was characterized. These plants were salt sensitive, and there was a specific reduction in enolase abundance in the tonoplast from salt-treated plants. Moreover, tonoplast isolated from mutant plants showed an impaired ability for aldolase stimulation of V-ATPase hydrolytic activity. The association of glycolytic proteins with the tonoplast may not only channel ATP to the V-ATPase, but also directly upregulate H + -pump activity.

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“…Many studies have also noted that the regulation properties of plant aquaporins can provide useful indications about their integrated function (Vera-Estrella et al, 2004;Chaumont et al, 2005;Boursiac et al, 2008;Maurel et al, 2008). In addition to regulated opening and closing (gating), plant aquaporins were shown to undergo highly controlled subcellular trafficking as a critical point for regulating their expression and function.…”

Section: Introductionmentioning

confidence: 99%

Single-Molecule Analysis of PIP2;1 Dynamics and Partitioning Reveals Multiple Modes of Arabidopsis Plasma Membrane Aquaporin Regulation

et al. 2011

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PIP2;1 is an integral membrane protein that facilitates water transport across plasma membranes. To address the dynamics of Arabidopsis thaliana PIP2;1 at the single-molecule level as well as their role in PIP2;1 regulation, we tracked green fluorescent protein-PIP2;1 molecules by variable-angle evanescent wave microscopy and fluorescence correlation spectroscopy (FCS). Single-particle tracking analysis revealed that PIP2;1 presented four diffusion modes with large dispersion of diffusion coefficients, suggesting that partitioning and dynamics of PIP2;1 are heterogeneous and, more importantly, that PIP2;1 can move into or out of membrane microdomains. In response to salt stress, the diffusion coefficients and percentage of restricted diffusion increased, implying that PIP2;1 internalization was enhanced. This was further supported by the decrease in PIP2;1 density on plasma membranes by FCS. We additionally demonstrated that PIP2;1 internalization involves a combination of two pathways: a tyrphostin A23-sensitive clathrin-dependent pathway and a methyl-b-cyclodextrin-sensitive, membrane raft-associated pathway. The latter was efficiently stimulated under NaCl conditions. Taken together, our findings demonstrate that PIP2;1 molecules are heterogeneously distributed on the plasma membrane and that clathrin and membrane raft pathways cooperate to mediate the subcellular trafficking of PIP2;1, suggesting that the dynamic partitioning and recycling pathways might be involved in the multiple modes of regulating water permeability.

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Novel Regulation of Aquaporins during Osmotic Stress

Cited by 185 publications

References 61 publications

AtTIP1;3 and AtTIP5;1, the only highly expressed Arabidopsis pollen‐specific aquaporins, transport water and urea

AtTIP1;3 and AtTIP5;1, the only highly expressed Arabidopsis pollen‐specific aquaporins, transport water and urea

Quantitative Proteomics of the Tonoplast Reveals a Role for Glycolytic Enzymes in Salt Tolerance

Single-Molecule Analysis of PIP2;1 Dynamics and Partitioning Reveals Multiple Modes of Arabidopsis Plasma Membrane Aquaporin Regulation

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