title: Novel strategies to an auxin-evoked transport control.
abstract: The auxin, indole acetic acid (IAA), was found to bring about a bimodal response in the activity of the inward K+ rectifier in intact Vicia faba guard cells: 10 microM IAA led to an increase in current through the K+ rectifier, whilst 100 microM IAA inhibited the current flow. Application of a synthetic oligopeptide (A6.1), corresponding in sequence to the C-terminal 12 residues of the major Zea mays auxin binding protein (ZmABP1), led to a reversible closure of the inward K+ channel with Ki/0.5 for peptide A6.1 of around 5 microM. In addition, peptide A6.1 and homologues corresponding to the C-terminal sequence of ZmABP1, were effective at 1 microM in stimulating binding of GTP gamma S to microsomal fraction membranes. In contrast, oligopeptides corresponding to other solvent-exposed domains of the auxin binding protein were ineffective in these assays.
authors.affiliation: Department of Biochemistry and Molecular Biology, Leeds University, UK.
authors.forename: P A
authors.initials: PA
authors.lastname: Millner
authors.forename: I R
authors.initials: IR
authors.lastname: White
authors.forename: D A
authors.initials: DA
authors.lastname: Groarke
authors.forename: G
authors.initials: G
authors.lastname: Theil
authors.forename: M R
authors.initials: MR
authors.lastname: Blatt
mesh_terms: D002462:Cell Membrane / Q000378:metabolism; D007887:Fabaceae / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism*; D010937:Plant Growth Regulators; D010940:Plant Proteins; D010946:Plants, Medicinal; D015221:Potassium Channels / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D010940:Plant Proteins; D015221:Potassium Channels; D011956:Receptors, Cell Surface; C046131:auxin receptor, plant; D019204:GTP-Binding Proteins