3 years ago

PknG senses amino acid availability to control metabolism and virulence of <i>Mycobacterium tuberculosis</i>

Andrew R. Bottrill, Natalie R. Lazar-Adler, Fabien le Chevalier, Liem Nguyen, Marco Bellinzoni, Barbara Rieck, Francesca Boldrin, Wafa Frigui, Alessandro Cascioferro, Pedro M. Alzari, Helen M. O’Hare, Roland Brosch, Riccardo Manganelli, María-Natalia Lisa, Giulia Degiacomi, Michael Zimmermann, Uwe Sauer

by Barbara Rieck, Giulia Degiacomi, Michael Zimmermann, Alessandro Cascioferro, Francesca Boldrin, Natalie R. Lazar-Adler, Andrew R. Bottrill, Fabien le Chevalier, Wafa Frigui, Marco Bellinzoni, María-Natalia Lisa, Pedro M. Alzari, Liem Nguyen, Roland Brosch, Uwe Sauer, Riccardo Manganelli, Helen M. O’Hare

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.

Publisher URL: http://journals.plos.org/plosone/article

DOI: 10.1371/journal.ppat.1006399

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.