title: Phosphorylated non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase from heterotrophic cells of wheat interacts with 14-3-3 proteins.
abstract: Glyceraldehyde-3-phosphate dehydrogenases catalyze key steps in energy and reducing power partitioning in cells of higher plants. Phosphorylated non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase (GAPN) present in heterotrophic cells of wheat (Triticum aestivum) was activated up to 3-fold by MgCl2. The effect was not observed with the non-phosphorylated enzyme found in leaves. The divalent cation also affected the response of the enzyme from endosperm and shoots to adenine nucleotides and inorganic pyrophosphate. Gel filtration chromatography, co-immunoprecipitation followed by immunostaining, and the use of a phosphopeptide containing a canonical binding motif showed that MgCl2 actually disrupted the interaction between GAPN and a 14-3-3 regulatory protein. After interaction with 14-3-3, phosphorylated GAPN exhibits a 3-fold lower Vmax and higher sensitivity to inhibition by ATP and pyrophosphate. Results suggest that GAPN is a target for regulation by phosphorylation, levels of divalent cations, and 14-3-3 proteins. The regulatory mechanism could be critical to maintain levels of energy and reductants in the cytoplasm of heterotrophic plant cells.
authors.affiliation: Instituto Tecnológico de Chascomús, Camino Circunvalación Laguna km 6, CC 164, B7130IWA Chascomús, Argentina.
authors.forename: Diego M
authors.initials: DM
authors.lastname: Bustos
authors.forename: Alberto A
authors.initials: AA
authors.lastname: Iglesias
mesh_terms: D048948:14-3-3 Proteins; D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D002413:Cations, Divalent / Q000494:pharmacology; D002478:Cells, Cultured; D002850:Chromatography, Gel; D011756:Diphosphates / Q000378:metabolism; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D010940:Plant Proteins / Q000378:metabolism; D014908:Triticum / Q000378:metabolism*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*
chemical_list: D048948:14-3-3 Proteins; D002413:Cations, Divalent; D011756:Diphosphates; D010750:Phosphoproteins; D010940:Plant Proteins; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D014446:Tyrosine 3-Monooxygenase; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases