High-affinity binding sites for abscisic acid on the plasmalemma of Vicia faba guard cells

Hornberg, Claudia; Weiler, Elmar W.

doi:10.1038/310321a0

Cited by 233 publications

(94 citation statements)

References 20 publications

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“…There are reports of plasma membrane-associated glycoproteins (9,29) and an ABAbinding protein (18). However, the significance of research for the structure and function of the plasma membrane to identify Ca-binding proteins (9), auxin receptors (19), or proteins phosphorylated in response to auxin, Ca, and calmodulin (26,39) is diminished by the use of uncharacterized microsomal membranes.…”

Section: Discussionmentioning

confidence: 99%

Electrophoretic Characterization of a Detergent-Treated Plasma Membrane Fraction from Corn Roots

Gallagher

Leonard²

1987

Plant Physiol.

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Experiments were conducted to determine conditions essential for electrophoretic characterization of a detergent-extracted plasma membrane fraction from corn (Zea mays L.) roots. Sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) initially gave poor resolution of polypeptides in the plasma membrane fraction and, upon detergent treatment for purification of the proton-pumping adenosine triphosphatase (ATPase), showed no enrichment for a 100 kilodalton catalytic subunit characteristic of the ATPase. In contrast to SDS-PAGE, phenol urea acetic acid (PAU)-PAGE clearly resolved two polypeptides in the 100 kilodalton region that were enriched during detergent treatment and indicated at least one polypeptide forms a phosphorylated intermediate characteristic of the ATPase. Problems with SDS-PAGE were found to be caused, in part, by a combination of endogenous proteases and heat-induced aggregation of high molecular weight proteins. The usually standard procedure of boiling the sample prior to SDS-PAGE caused the aggregation of the 100 kilodalton polypeptides. By controlling for proteases using chymostatin and/or phenylmethane sulfonyl floride, and not boiling the sample prior to electrophoresis, two polypeptides were clearly resolved by SDS-PAGE in the 100 kilodalton region of Triton X-l 14-extracted membranes from corn, oat, barley, and tomato.The transport of most of the essential mineral nutrients into root cells involves ion carriers in the plasma membrane which are most likely integral proteins or protein complexes which span the membrane (23). Purification and characterization of carrier proteins requires the ability to extract plasma membrane vesicles with detergents without significant denaturation of integral proteins and the ability to follow purification of plasma membrane polypeptides by electrophoresis (17,24,35).The selection ofdetergents and the determination ofextraction conditions for purification of integral proteins cannot be based strictly on theoretical grounds, but must be determined empirically (16, 17). There are many detergents available for use in removing proteins from the membrane, and there are several types of strategies which can be used to purify integral membrane proteins (17,35,36). The two approaches most often used involve removal of peripheral proteins by treatment with low concentrations of detergent followed by recovery of the integral protein still associated with the extracted membrane (negative purification) and/or solubilization of the membrane at a detergent concentration near its critical micelle concentration and ' Supported in part by National Science Foundation grant PCM 8025004.2 Present address: Biological Sciences Department, Stanford University, Stanford, CA 94305. separation of integral proteins by, for example, rate zonal centrifugation or affinity chromatography (positive purification). The success of these approaches is greatly influenced by the initial proportion of the protein of interest in the membrane and the extent of purification...

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Section: Discussionmentioning

confidence: 99%

Electrophoretic Characterization of a Detergent-Treated Plasma Membrane Fraction from Corn Roots

Gallagher

Leonard²

1987

Plant Physiol.

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“…With the exception of an unconfirmed report in 1984 (75), no ABA receptors have been described. Using surface plasmon resonance in conjunction with flow cytometry, Desikan et al (60) provided indirect evidence for a putative ABA-receptor complex that interacts with a cell-surface glycoprotein.…”

Section: La 3ϩ and Pld Interaction With Aba Effectors Vp1 And Abi1mentioning

confidence: 99%

Functional Interactions of Lanthanum and Phospholipase D with the Abscisic Acid Signaling Effectors VP1 and ABI1-1 in Rice Protoplasts

Gampala

Hagenbeek

Rock

2001

Journal of Biological Chemistry

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cis,trans-Abscisic acid (ABA) plays an important role in plant growth and development, regulation of seed maturation, germination, and adaptation to environmental stresses. Knowledge of ABA mechanisms of action and the interactions of components required for ABA signal transduction is far from complete. Using transient gene expression in rice protoplasts, we observed additive and inhibitory effects between maize VP1 (Viviparous-1, a transcriptional activator) and a dominant-negative mutant protein phosphatase, ABI1-1 (ABA-insensitive-1-1), from Arabidopsis. Lanthanide ions were shown to be specific agonists of ABA-inducible gene expression and to interact synergistically with ABA and overexpressed VP1. Both VP1 and lanthanum activities could be antagonized by coexpression of ABI1-1, which demonstrates the specific ABA dependence of these effectors on ABA-regulated gene expression. We obtained pharmacological evidence that phospholipase D (PLD) functions in ABA-inducible gene expression in rice. Antagonism of ABA, VP1, and lanthanum synergy by 1-butanol, a specific inhibitor of PLD, was similar to the inhibition by coexpression of ABI1-1. These results demonstrate that ABA, VP1, lanthanum, PLD, and ABI1 are all involved in ABA-regulated gene expression and are consistent with an integrated model whereby La 3؉ acts upstream of PLD.cis,trans-Abscisic acid (ABA) 1 modulates seed development, dormancy, cell division, stomatal movements, and cellular responses to environmental stresses such as drought, cold, salt, pathogen attack, and UV light (1-3). Despite its importance in plant growth and development, the mechanisms of ABA action are largely unknown, and there may be more than one ABA signal transduction pathway leading to both fast (guard cell ion fluxes) and slow (gene regulation) cellular responses (4 -6). Transient gene expression studies with LEA (late embryogenesis abundant) and drought-inducible gene promoters have defined the cis-acting elements necessary and sufficient to confer ABA-inducible transcription (7-10). Separate ABA-responsive elements and coupling elements function cooperatively and redundantly as an ABA response complex (9,11,12).Recent insight into the mechanisms of ABA-inducible transcription have come from cloning of TRAB1 (transcription factor responsible for ABA regulation), a basic leucine zipper transcription factor that binds ABA response complex promoter elements and VP1 (Viviparous-1), a transcriptional activator required for ABA-regulated gene expression during seed maturation (13-15). Other proteins interact with ABA response complexes, VP1 orthologs, and basic leucine zipper factors, but there is no direct evidence that these factors function in ABA signaling (16 -27). Regulation by ABA of TRAB1 and VP1 transactivation of ABA response complexes is not at the level of DNA binding, based on transient gene expression and in vivo footprinting assays (13,28). Consistent with this model is the finding that the bean ortholog of VP1, PvALF, functions to remodel chromatin independent of e...

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“…The data presented here support the view that Ca and ABA do not have directly interchangeable roles. Experiments on the mode of action of ABA have suggested that guard cells respond to it on the external side of the plasmalemma (Hartung, 1983;Hornberg & Weiler, 1984) and not as postulated for Ca, within the cytoplasm.…”

Section: Discussionmentioning

confidence: 99%

Does calcium in xylem sap regulate stomatal conductance?

1990

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SUMMARYWhole plants and individual leaves of Commelina communis and Triticum aestivum were used to study the influence of changes in apoplastic Ca on the regulation of gas-exchange, in particular stomatal conductance (g) and transpiration (E). Plants grown in nutrient solution at a low concentration of Ca (1 mol m"*) were used in experiments where rapid changes in Ca concentration were induced via the rhizosphere or by direct entry into the xylem. Solutions containing Ca^"^ ions were applied directly to the leaf surface and also through the cut end of detached leaves and via a xylem feeding system to attached leaves. Putative Ca-channel blockers (lanthanum chloride and verapamil hydrochloride), which are believed to deny Ca entry into the cytoplasm, were also used to provide more information about the nature of the action of Ca on the guard cells.In all the experimental systems used, the short-term application of 8 mol m~^ Ca induced reductions in both g and E, but when longer-term changes in the calcium concentrations in the xylem sap were induced through changes in Ca supply from the rhizosphere, no change in g was apparent. These experiments raise innportant questions about how plants with an abundant supply of calcium in the rhizosphere prevent high concentrations of apoplastic calcium from interfering in the stomatal mechanism. The data presented do not preclude the possibility that a pulse of calcium ions delivered into the xylem could be used in root-shoot communication.

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High-affinity binding sites for abscisic acid on the plasmalemma of Vicia faba guard cells

Cited by 233 publications

References 20 publications

Electrophoretic Characterization of a Detergent-Treated Plasma Membrane Fraction from Corn Roots

Electrophoretic Characterization of a Detergent-Treated Plasma Membrane Fraction from Corn Roots

Functional Interactions of Lanthanum and Phospholipase D with the Abscisic Acid Signaling Effectors VP1 and ABI1-1 in Rice Protoplasts

Does calcium in xylem sap regulate stomatal conductance?

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