A Novel Cytosolic Dual Specificity Phosphatase, Interacting with Glucokinase, Increases Glucose Phosphorylation Rate - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Biological Chemistry Année : 2000

A Novel Cytosolic Dual Specificity Phosphatase, Interacting with Glucokinase, Increases Glucose Phosphorylation Rate

Maria Muñoz-Alonso
  • Fonction : Auteur
Nadim Kassis
  • Fonction : Auteur
Jean Girard
  • Fonction : Auteur
Anne-Françoise Burnol
  • Fonction : Auteur
Armelle Leturque
  • Fonction : Auteur

Résumé

A novel protein was cloned from a rat liver cDNA library by interaction with the liver glucokinase. This protein contained 339 residues and possessed a canonical consensus sequence for a dual specificity phosphatase. The recombinant protein was able to dephosphorylate phosphotyrosyl and phosphoseryl/threonyl substrates. We called this protein the glucokinase-associated phosphatase (GKAP). The GKAP partially dephosphorylated the recombinant glucokinase previously phosphorylated, in vitro, by protein kinase A. The GKAP fused with green fluorescent protein was located in the cytosol, where glucokinase phosphorylates glucose, and not in the nucleus where the glucokinase is retained inactive by the glucokinase regulatory protein. More importantly, the GKAP accelerated the glucokinase activity in a dose-dependent manner and with a stoichiometry compatible with a physiological mechanism. This strongly suggested that the interaction between GKAP and glucokinase had a functional significance. The cloning of this novel protein with a dual specificity phosphatase activity allows the description of a possible new regulatory step in controlling the glycolysis flux.

Dates et versions

hal-03990170 , version 1 (15-02-2023)

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Citer

Maria Muñoz-Alonso, Ghislaine Guillemain, Nadim Kassis, Jean Girard, Anne-Françoise Burnol, et al.. A Novel Cytosolic Dual Specificity Phosphatase, Interacting with Glucokinase, Increases Glucose Phosphorylation Rate. Journal of Biological Chemistry, 2000, 275 (42), pp.32406-32412. ⟨10.1074/jbc.M000841200⟩. ⟨hal-03990170⟩
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