Characterization of Plasma Membrane MIP Proteins in Maize

Chaumont, François; Wilder, Valérie Van; Fetter, Karolina; Barrieu, François; Chrispeels, Maarten J.

doi:10.1007/978-1-4615-1203-5_37

Cited by 4 publications

(2 citation statements)

References 5 publications

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“…Evidence suggests that this phosphorylation is due to a membrane‐associated calcium‐dependent protein kinase. Phosphorylation of Arabidopsis and maize plasma membrane aquaporins has also been detected in vivo by mass spectrometry or radioactive labelling (Chaumont et al, 2000a; Santoni et al, 2003; V. Van Wilder, H. Degand, R. Derua, E. Waelkens and F. Chaumont, unpublished data).…”

Section: Phosphorylationmentioning

confidence: 99%

Regulation of plant aquaporin activity

Chaumont

Moshelion

Daniels

2005

Biology of the Cell

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261

217

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Accumulating evidence indicates that aquaporins play a key role in plant water relations. Plant aquaporins are part of a large and highly divergent protein family that can be divided into four subfamilies according to amino acid sequence similarity. As in other organisms, plant aquaporins facilitate the transcellular movement of water, but, in some cases, also the flux of small neutral solutes across a cellular membrane. Plant cell membranes are characterized by a large range of osmotic water permeabilities, and recent data indicate that plant aquaporin activity might be regulated by gating mechanisms. The factors affecting the gating behaviour possibly involve phosphorylation, heteromerization, pH, Ca 2+ , pressure, solute gradients and temperature. Regulation of aquaporin trafficking may also represent a way to modulate membrane water permeability. The aim of this review is to integrate recent molecular and biophysical data on the mechanisms regulating aquaporin activity in plant membranes and to relate them to putative changes in protein structure.

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Section: Phosphorylationmentioning

confidence: 99%

Regulation of plant aquaporin activity

Chaumont

Moshelion

Daniels

2005

Biology of the Cell

Self Cite

261

217

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“…The results are surprising because they mean that, in the PIP1AS plants, the PIP2 aquaporins are inactive and conversely that in PIP2AS-a plants, the PIP1 aquaporins are inactive. PIP1 aquaporins are usually inactive in the Xenopus oocyte swelling assay; however, they can be activated by very small amounts of PIP2 aquaporins (Chaumont et al, 2000b), suggesting that these two classes of aquaporins may function cooperatively. (Tyree et al, 1998).…”

Section: Expression and Activity Of Aquaporinsmentioning

confidence: 99%

Plasma Membrane Aquaporins Play a Significant Role during Recovery from Water Deficit

et al. 2002

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The role of plasma membrane aquaporins (PIPs) in water relations of Arabidopsis was studied by examining plants with reduced expression of PIP1 and PIP2 aquaporins, produced by crossing two different antisense lines. Compared with controls, the double antisense (dAS) plants had reduced amounts of PIP1 and PIP2 aquaporins, and the osmotic hydraulic conductivity of isolated root and leaf protoplasts was reduced 5-to 30-fold. The dAS plants had a 3-fold decrease in the root hydraulic conductivity expressed on a root dry mass basis, but a compensating 2.5-fold increase in the root to leaf dry mass ratio. The leaf hydraulic conductance expressed on a leaf area basis was similar for the dAS compared with the control plants. As a result, the hydraulic conductance of the whole plant was unchanged. Under sufficient and under water-deficient conditions, stomatal conductance, transpiration rate, plant hydraulic conductance, leaf water potential, osmotic pressure, and turgor pressure were similar for the dAS compared with the control plants. However, after 4 d of rewatering following 8 d of drying, the control plants recovered their hydraulic conductance and their transpiration rates faster than the dAS plants. Moreover, after rewatering, the leaf water potential was significantly higher for the control than for the dAS plants.From these results, we conclude that the PIPs play an important role in the recovery of Arabidopsis from the water-deficient condition.Water transport through cellular membranes is facilitated by aquaporins, proteins that form waterselective channels. The presence of aquaporins in a membrane can increase the osmotic hydraulic conductivity of the membrane (L P , meters per second per megapascal) by 10-to 20-fold (Preston et al., 1992). In plants, the physiological importance of aquaporins is currently mainly inferred from their widespread occurrence (Johansson et al., 2000) and the use of HgCl 2 , a nonspecific inhibitor (Tyerman et al., 2002). Aquaporins, which are found in almost all types of tissues (Maurel, 1997), have changed the way we think about plant water relations (Maurel and Chrispeels, 2001).Water movement through a living organ such as a root or a leaf can take an apoplastic route, which has a low resistance to flow, or a transcellular route, which has a higher resistance because water has to move through lipid bilayer membranes . Bulk water flow associated with the transpiration stream is mostly apoplastic, except in the root exo-and endodermis (Zimmermann et al., 2000) and in the leaf bundle sheath (Koroleva et al., 2002), where apoplastic barriers (Casparian band, suberin lamellae, and secondary cell wall thickening) restrict the apoplastic path. Other important processes such as cell enlargement, refilling of embolized vessels, and movement of guard cells and pulvini may require rapid transport of water across membranes. Furthermore, the considerable growth-associated water potential difference (0.1-0.3 MPa) found in most growing organs of herbaceous plants (e.g. Nonami and Boyer, 1...

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Plant aquaporins: multifunctional water and solute channels with expanding roles

Tyerman¹,

Niemietz²,

Bramley³

2002

Plant Cell & Environment

561

360

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There is strong evidence that aquaporins are central components in plant water relations. Plant species possess more aquaporin genes than species from other kingdoms. According to sequence similarities, four major groups have been identified, which can be further divided into subgroups that may correspond to localization and transport selectivity. They may be involved in compatible solute distribution, gas-transfer (CO 2 , NH 3 ) as well as in micronutrient uptake (boric acid). Recent advances in determining the structure of some aquaporins gives further details on the mechanism of selectivity. Gating behaviour of aquaporins is poorly understood but evidence is mounting that phosphorylation, pH, pCa and osmotic gradients can affect water channel activity. Aquaporins are enriched in zones of fast cell division and expansion, or in areas where water flow or solute flux density would be expected to be high. This includes biotrophic interfaces between plants and parasites, between plants and symbiotic bacteria or fungi, and between germinating pollen and stigma. On a cellular level aquaporin clusters have been identified in some membranes. There is also a possibility that aquaporins in the endoplasmic reticulum may function in symplasmic transport if water can flow from cell to cell via the desmotubules in plasmodesmata. Functional characterization of aquaporins in the native membrane has raised doubt about the conclusiveness of expression patterns alone and need to be conducted in parallel. The challenge will be to elucidate gating on a molecular level and cellular level and to tie those findings into plant water relations on a macroscopic scale where various flow pathways need to be considered.

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Characterization of Plasma Membrane MIP Proteins in Maize

Cited by 4 publications

References 5 publications

Regulation of plant aquaporin activity

Regulation of plant aquaporin activity

Plasma Membrane Aquaporins Play a Significant Role during Recovery from Water Deficit

Plant aquaporins: multifunctional water and solute channels with expanding roles

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