Escherichia coli glycogen metabolism is controlled by the PhoP-PhoQ regulatory system at submillimolar environmental Mg2+ concentrations, and is highly interconnected with a wide variety of cellular processes - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Biochemical Journal Année : 2009

Escherichia coli glycogen metabolism is controlled by the PhoP-PhoQ regulatory system at submillimolar environmental Mg2+ concentrations, and is highly interconnected with a wide variety of cellular processes

Manuel Montero
  • Fonction : Auteur
Gustavo Eydallin
  • Fonction : Auteur
Alejandro M. Viale
  • Fonction : Auteur
Goizeder Almagro
  • Fonction : Auteur
Francisco J. Muñoz
  • Fonction : Auteur
Mehdi Rahimpour
  • Fonction : Auteur
María T. Sesma
  • Fonction : Auteur
Edurne Baroja-Fernández
  • Fonction : Auteur

Résumé

Using the Keio collection of gene-disrupted mutants of Escherichia coli we have recently carried out a genome-wide screening of the genes affecting glycogen metabolism. Among the mutants identified in the study, ΔmgtA, ΔphoP and ΔphoQ cells, all lacking genes that are induced under low extracellular Mg2+ conditions, displayed glycogen-deficient phenotypes. In this work we show that these mutants accumulated normal glycogen levels when the culture medium was supplemented with submillimolar Mg2+ concentrations. Expression analyses conducted in wild type, ΔphoP and ΔphoQ cells showed that the glgCAP operon is under PhoP-PhoQ control in the submillimolar Mg2+ concentration range. Subsequent screening of the Keio collection under non-limiting Mg2+ allowed the identification of 183 knock-out mutants with altered glycogen levels. The stringent and general stress responses, end-turnover of tRNA, intracellular AMP levels, and metabolism of amino acids, iron, carbon and sulfur were major determinants of glycogen levels. glgC::lacZY expression analyses using mutants representing different functional categories revealed that the glgCAP operon belongs to the RelA regulon. We propose an integrated metabolic model wherein glycogen metabolism is (a) tightly controlled by the energy and nutritional status of the cell and (b) finely regulated by changes in environmental Mg2+ occurring at the submillimolar concentration range.

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hal-00479214 , version 1 (30-04-2010)

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Manuel Montero, Gustavo Eydallin, Alejandro M. Viale, Goizeder Almagro, Francisco J. Muñoz, et al.. Escherichia coli glycogen metabolism is controlled by the PhoP-PhoQ regulatory system at submillimolar environmental Mg2+ concentrations, and is highly interconnected with a wide variety of cellular processes. Biochemical Journal, 2009, 424 (1), pp.129-141. ⟨10.1042/BJ20090980⟩. ⟨hal-00479214⟩

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