Research article summary (published 21 Oct 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.

Full Abstract

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, Delta mgtA, Delta phoP and Delta phoQ 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, Delta phoP and Delta phoQ 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.

Author information

Author/s: Montero, Manuel (M); Eydallin, Gustavo (G); Viale, Alejandro M (AM); Almagro, Goizeder (G); Muñoz, Francisco J (FJ); Rahimpour, Mehdi (M); Sesma, María T (MT); Baroja-Fernández, Edurne (E); Pozueta-Romero, Javier (J);

Affiliation: Instituto de Agrobiotecnología (CSIC, UPNA, Gobierno de Navarra), Mutiloako etorbidea zenbaki gabe, 31192 Mutiloabeti, Nafarroa, Spain.

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: The Biochemical journal (Biochem J), published in England. (Language: eng)

Reference: 2009-Nov; vol 424 (issue 1) : pp 129-41

Dates: Created 2009/10/20; Completed 2009/11/03;

PMID: 19702577, status: MEDLINE (last retrieval date: 11/3/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Bacterial Proteins - genetics; metabolism Blotting, Western Escherichia coli - drug effects; genetics; metabolism Escherichia coli Proteins - genetics; metabolism; physiology

Gene Expression Regulation, Bacterial - drug effects; genetics Glycogen - genetics; metabolism Magnesium - pharmacology Operon - genetics; physiology

Associated Chemicals: Bacterial Proteins (0) ; Escherichia coli Proteins (0) ; PhoP protein, E coli (0) ; PhoQ protein, Bacteria (0) ; Magnesium (7439-95-4) ; Glycogen (9005-79-2)

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