title: Divalent cation effects on interactions between multiple Arabidopsis 14-3-3 isoforms and phosphopeptide targets.
abstract: Oscillations in cellular divalent cation concentrations are key events that can trigger signal transduction cascades. Common cellular divalent cations, such as calcium and magnesium, interact with 14-3-3 proteins. The metal ion interaction causes a conformational change in the 14-3-3 proteins, which is manifested as an increase in hydrophobicity. In this study, the effect of divalent cations on the interaction between 14-3-3 proteins and target peptides was investigated using surface plasmon resonance and isothermal titration calorimetry. The binding between ten recombinant Arabidopsis 14-3-3 isoforms and two synthetic target peptides was observed in the presence of various physiologically relevant concentrations of calcium or magnesium, from 1 microM to 1 mM or from 1 microM to 5 mM, respectively. The synthetic target peptides were based on sequences from Arabidopsis nitrate reductase (NR2) and the plasma membrane proton pump (AHA2) representing fundamentally different target classes. Isoforms representing every branch of the Arabidopsis 14-3-3 phylogenetic tree were tested. The general result for all cases is that an increased concentration of divalent cations in solution causes an increase in the concentration of 14-3-3 protein interacting with the respective phosphopeptide.
authors.affiliation: Program in Plant Molecular and Cellular Biology, Horticultural Sciences, University of Florida, 1143 Hull Road, Fifield Hall 110690, Gainesville, Florida 32611-0690, USA.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Manak
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Ferl
mesh_terms: D048948:14-3-3 Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology; D002413:Cations, Divalent / Q000494:pharmacology; D008274:Magnesium / Q000494:pharmacology; D046912:Multiprotein Complexes; D050901:Nitrate Reductase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010748:Phosphopeptides / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D048948:14-3-3 Proteins; D029681:Arabidopsis Proteins; D002413:Cations, Divalent; D046912:Multiprotein Complexes; D010748:Phosphopeptides; D020033:Protein Isoforms; D011994:Recombinant Proteins; D050901:Nitrate Reductase; D006180:Proton-Translocating ATPases; C479903:AHA2 protein, Arabidopsis; D008274:Magnesium; D002118:Calcium