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Title: PknG senses amino acid availability to control metabolism and virulence of Mycobacterium tuberculosis
Authors: Rieck, Barbara
Degiacomi, Giulia
Zimmermann, Michael
Cascioferro, Alessandro
Boldrin, Francesca
Lazar-Adler, Natalie R.
Bottrill, Andrew R.
le Chevalier, Fabien
Frigui, Wafa
Bellinzoni, Marco
Lisa, María-Natalia
Alzari, Pedro M.
Nguyen, Liem
Brosch, Roland
Sauer, Uwe
Manganelli, Riccardo
O’Hare, Helen M.
First Published: 17-May-2017
Publisher: Public Library of Science (PLoS)
Citation: PLoS Pathogens, 2017, 13(5): e1006399
Abstract: Sensing and response to changes in nutrient availability are essential for the lifestyle of environmental and pathogenic bacteria. Serine/threonine protein kinase G (PknG) is required for virulence of the human pathogen Mycobacterium tuberculosis, and its putative substrate GarA regulates the tricarboxylic acid cycle in M. tuberculosis and other Actinobacteria by protein-protein binding. We sought to understand the stimuli that lead to phosphorylation of GarA, and the roles of this regulatory system in pathogenic and non-pathogenic bacteria. We discovered that M. tuberculosis lacking garA was severely attenuated in mice and macrophages and furthermore that GarA lacking phosphorylation sites failed to restore the growth of garA deficient M. tuberculosis in macrophages. Additionally we examined the impact of genetic disruption of pknG or garA upon protein phosphorylation, nutrient utilization and the intracellular metabolome. We found that phosphorylation of GarA requires PknG and depends on nutrient availability, with glutamate and aspartate being the main stimuli. Disruption of pknG or garA caused opposing effects on metabolism: a defect in glutamate catabolism or depletion of intracellular glutamate, respectively. Strikingly, disruption of the phosphorylation sites of GarA was sufficient to recapitulate defects caused by pknG deletion. The results suggest that GarA is a cellular target of PknG and the metabolomics data demonstrate that the function of this signaling system is in metabolic regulation. This function in amino acid homeostasis is conserved amongst the Actinobacteria and provides an example of the close relationship between metabolism and virulence.
DOI Link: 10.1371/journal.ppat.1006399
ISSN: 1553-7366
eISSN: 1553-7374
Version: Publisher Version
Status: Peer-reviewed
Type: Journal Article
Rights: Copyright © the authors, 2017. This is an open-access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Appears in Collections:Published Articles, Dept. of Infection, Immunity and Inflammation

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