Journal Article

Nonphosphorylating Glyceraldehyde-3-Phosphate Dehydrogenase Is Phosphorylated in Wheat Endosperm at Serine-404 by an SNF1-Related Protein Kinase Allosterically Inhibited by Ribose-5-Phosphate

Iglesias, Alberto Álvaro, Bustos, Diego Martín, Piattoni, Claudia Vanesa, Guerrero, Sergio Adrián

2011

Overview

Nonphosphorylating glyceraldehyde-3-phosphate dehydrogenase (np-Ga3PDHase) is a cytosolic unconventional glycolytic enzyme of plant cells regulated by phosphorylation in heterotrophic tissues. After interaction with 14-3-3 proteins, the phosphorylated enzyme becomes less active and more sensitive to regulation by adenylates and inorganic pyrophosphate. Here, we acknowledge that in wheat (Triticum aestivum), np-GaSPDHase is specifically phosphorylated by the SnRK (SNF1-related) protein kinase family. Interestingly, only the kinase present in heterotrophic tissues (endosperm and shoots, but not in leaves) was found active. The specific SnRK partially purified from endosperm exhibited a requirement for Mg²⁺ or Mn²⁺ (being Ca²⁺ independent), having a molecular mass of approximately 200 kD. The kinase also phosphorylated standard peptides SAMS, AMARA, and SP46, as well as endogenous sucrose synthase, results suggesting that it could be a member of the SnRKl subfamily. Concurrently, the partially purified wheat SnRK was recognized by antibodies raised against a peptide conserved between SnRKls from sorghum (Sorghum bicolor) and maize (Zea mays) developing seeds. The wheat kinase was allosterically inhibited by ribose-5-phosphate and, to a lesser extent, by fructose-1,6-bisphosphate and 3-phosphoglycerate, while glucose-6-phosphate (the main effector of spinach [Spinacia olerácea] leaves, SnRKl) and trehalose-6-phosphate produced little or no effect. Results support a distinctive allosteric regulation of SnRKl present in photosynthetic or heterotrophic plant tissues. After in silico analysis, we constructed two np-Ga3PDHase mutants, S404A and S447A, identifying serine-404 as the target of phosphorylation. Results suggest that both np-Ga3PDHase and the specific kinase could be under control, critically affecting the metabolic scenario involving carbohydrates and reducing power partition and storage in heterotrophic plant cells.

• Publisher: American Society of Plant Biologists
• Subject: Allosteric Regulation / Allosteric Regulation - drug effects / Amino Acid Sequence / antagonists & inhibitors / BIOCHEMICAL PROCESSES AND MACROMOLECULAR STRUCTURES / Biological and medical sciences / Cations, Divalent / Cations, Divalent - pharmacology / chemistry / corn / Dehydrogenases / drug effects / Endosperm / Endosperm - drug effects / Endosperm - enzymology / Enzymes / enzymology / Fructosediphosphates / Fructosediphosphates - pharmacology / Fundamental and applied biological sciences. Psychology / glucose 6-phosphate / glyceraldehyde-3-phosphate dehydrogenase / Glyceraldehyde-3-Phosphate Dehydrogenases / Glyceraldehyde-3-Phosphate Dehydrogenases - metabolism / Glyceric Acids / Glyceric Acids - pharmacology / inorganic pyrophosphatase / isolation & purification / Kinetics / leaves / metabolism / Models, Biological / Molecular Sequence Data / molecular weight / Organ Specificity / Organ Specificity - drug effects / Peptides / Peptides - metabolism / pharmacology / Phosphates / phosphorylase kinase / Phosphorylation / Phosphorylation - drug effects / Phosphoserine / Phosphoserine - metabolism / Physiological regulation / Plant cells / Plant physiology and development / plant tissues / Plants / Protein Serine-Threonine Kinases / Protein Serine-Threonine Kinases - antagonists & inhibitors / Protein Serine-Threonine Kinases - chemistry / Protein Serine-Threonine Kinases - isolation & purification / Protein Serine-Threonine Kinases - metabolism / proteins / Ribosemonophosphates / Ribosemonophosphates - pharmacology / Sequence Alignment / shoots / Sorghum bicolor / Spinach / Spinacia oleracea / sucrose synthase / Triticum / Triticum - drug effects / Triticum - enzymology / Triticum aestivum / wheat / Zea mays