Promotion of cation transport across phospholipid vesicular membranes by the plant hormone indole-3-acetic acid as studied by 1H-NMR

Jones, Graham P.; Starr, R.; Paleg, L. G.

doi:10.1016/0005-2736(85)90523-1

Cited by 8 publications

(2 citation statements)

References 17 publications

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“…the regulation of ionic fluxes. The passive permeability to cations is enhanced on artificial lipid vesicles (15). An H+-excretion, probably linked to the plasmalemma proton pump is stimulated in several tissues, including pea stem segments or maize coleoptiles (20), oat coleoptile sections (7) or rape leaf protoplasts (28).…”

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confidence: 99%

Auxin Effect on the Transmembrane Potential Difference of Wild-Type and Mutant Tobacco Protoplasts Exhibiting a Differential Sensitiity to Auxin

Ephritikhine¹,

Barbier‐Brygoo²,

Müller³

et al. 1987

Plant Physiol.

100

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The effects of 1-naphthaleneacetic acid (NAA) and other auxin analogs on the transmembrane potential difference (Em) were compared on tobacco protoplasts isolated from two genotypes differing in their sensitivity to auxins. For both types, NAA modifies Em by inducing at low doses a hyperpolarization, the amplitude of which increased with auxin concentration. Above an optimal concentration this hyperpolarization was reduced and even nullified. However, for the mutant type, this electrical response was shifted toward higher NAA concentrations, as its growth response. In the presence of structural analogs of auxin which have been showed to modify the dose-response curve for growth, the Em was altered: the growth-stimulatory molecule (picloram) initiated hyperpolarization, whereas the growth-inhibitory substance (4-bromophenylacetic acid) caused depolarization. These results provide evidence for a specific action of auxin at the membrane level related to its biological activity.There is considerable evidence for interactions between auxin and membranes. Ultrastructural alterations were induced by auxin in isolated and in situ soybean plasma membranes (22). Modifications of the physical properties of membranes after auxin treatment have been reported. These include an increase in the microviscosity of lipid bilayers (17) or plasma membrane vesicles (13) and changes in electrostatic surface properties of protoplasts (29). Finally, a specific binding of auxin to membranes isolated from maize coleoptiles (9) and tobacco cell suspensions (30) tiles (24).Causal links between these effects of auxin on membrane properties and the biological activity of auxin are difficult to establish. Very recently, binding of auxin at the plasmalemma of epidermal cells has been reported to be related to the elongation and the curling of corn coleoptiles (18). In other studies, the auxin-induced proton extrusion has been correlated to the elongation rate of shoots (12, 14, 25) and the control of root growth (10, 21) on the basis of similarities between the timing of the responses, the dependency upon auxin concentration, and the specificity of the response to auxin analogs. Such results provide evidence for the existence of a relationship between the action of auxin on membranes and the overall activity of this hormone on cell enlargement. Up to now, the involvement of hormoneinduced modifications of membranes into the control of cell division and differentiation has not been directly demonstrated.A novel opportunity to study the basis ofthe biological activity ofauxins at the cellular level was recently offered by the selection of a NAA-tolerant mutant from tobacco mesophyll protoplasts (5, 23). The wild-type (clone D8) and the mutant (clone 36) differ in their sensitivity to auxins as measured by the ability of the cells derived from protoplasts to proliferate in the presence of NAA. In this paper we test the hypothesis that the wild-type and mutant protoplasts differ in their membrane properties. A comparative study of the effe...

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confidence: 99%

Auxin Effect on the Transmembrane Potential Difference of Wild-Type and Mutant Tobacco Protoplasts Exhibiting a Differential Sensitiity to Auxin

Ephritikhine¹,

Barbier‐Brygoo²,

Müller³

et al. 1987

Plant Physiol.

100

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“…Modulation ofthe ATPase by this toxin appears to be complex and indirect since the reputed fusicoccin binding protein was purified away from plasma membrane ATPase activity (27). Cytokinins, auxins, and ABA alter membrane fluidity and permeability (8,13,26), which may indirectly effect ATPase activity. It is clear that modulation of vanadate-sensitive ATPase activity probably proceeds via numerous responses to environmental and developmental changes.…”

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confidence: 99%

Phospholipid Requirement of the Vanadate-Sensitive ATPase from Maize Roots Evaluated by Two Methods

Bräuer¹,

Tu²

1989

Plant Physiol.

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The activation of the vanadate-sensitive ATPase from maize (Zea mays L.) root microsomes by phospholipids was assessed by two different methods. First, the vanadate-sensitive ATPase was partially purified and substantially delipidated by treating microsomes with 0.6% deoxycholate (DOC) at a protein concentration of 1 milligram per milliliter. Vanadate-sensitive ATP hydrolysis by the DOC-extracted microsomes was stimulated up to 100% by the addition of asolectin. Of the individual phospholipids tested, phosphatidylserine and phosphafidylglycerol stimulated activity as much as asolectin, whereas phosphatidylcholine did not. Second, phospholipid dependence of the ATPase was also assessed by reconstituting the enzyme into proteoliposomes of differing phospholipid composition. In these experiments, the rate of proton transport and ATP hydrolysis was only slightly affected by phospholipid composition. DOC-extracted microsomes reconstituted with dioleoylphosphatidylcholine had rates of proton transport similar to those found with microsomes reconstituted with asolectin. The difference between the two types of assays is discussed in terms of factors contributing to the interaction between proteins and lipids.

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Proton NMR Studies of Transmembrane Solute Transport

King

Boyd

1991

Cell Membrane Transport

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Promotion of cation transport across phospholipid vesicular membranes by the plant hormone indole-3-acetic acid as studied by 1H-NMR

Cited by 8 publications

References 17 publications

Auxin Effect on the Transmembrane Potential Difference of Wild-Type and Mutant Tobacco Protoplasts Exhibiting a Differential Sensitiity to Auxin

Auxin Effect on the Transmembrane Potential Difference of Wild-Type and Mutant Tobacco Protoplasts Exhibiting a Differential Sensitiity to Auxin

Phospholipid Requirement of the Vanadate-Sensitive ATPase from Maize Roots Evaluated by Two Methods

Proton NMR Studies of Transmembrane Solute Transport

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