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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Microbiol. | doi: 10.3389/fmicb.2019.01942

The tyrosine-autokinase UbK is required for proper cell growth and cell morphology of Streptococcus pneumoniae

 Anaïs Pelletier1,  Céline Freton1,  Clément Gallay2,  Jennyfer Trouvé3, Caroline Cluzel4, Mirita Franz-Watchel5,  Boris Macek6, Jean-Michel Jault7, Christophe Grangeasse7* and  Sébastien GUIRAL8*
  • 1Molecular Microbiology and Structural Biochemistry - UMR5086 , Lyon , France, Université de Lyon, France
  • 2Université de Lausanne, Switzerland
  • 3UMR5075 Institut de Biologie Structurale (IBS), France
  • 4Laboratoire de Biologie Tissulaire et d'Ingénierie Thérapeutique UMR5305, Université de Lyon, France
  • 5University of Tübingen, Germany
  • 6Center of Quantitative Proteomics, University of Tuebingen, Germany
  • 7UMR5086 Microbiologie Moléculaire et Biochimie Structurale (MMSB), France
  • 8Molecular Microbiology and Structural Biochemistry - UMR5086, Université de Lyon, France

Protein phosphorylation is a key post-translational modification required for many cellular functions of the bacterial cell. Recently, we identified a new protein-kinase, named UbK, in Bacillus subtilis that belongs to a new family of protein-kinases widespread in bacteria. In this study, we analyze the function of UbK in Streptococcus pneumoniae. We show that UbK displays a tyrosine-kinase activity and autophosphorylates on a unique tyrosine in vivo. To get insights into its cellular role, we constructed a set of pneumococcal ubk mutants. Using conventional and electron microscopy, we show that the ubk deficient strain, as well as an ubk catalytic dead mutant, display both severe cell-growth an cell-morphology defects. The same defects are observed with a mutant mimicking permanent phosphorylation of UbK whereas they are not detected for a mutant mimicking defective autophosphorylation of UbK. Moreover, we find that UbK phosphorylation promotes its ability to hydrolyze ATP. These observations show that the hydrolysis of ATP by UbK serves not only for its autophosphorylation but also for a distinct purpose essential for the optimal cell growth and cell-morphogenesis of the pneumococcus. We thus propose a model in which the autophosphorylation / dephosphorylation of UbK regulates its cellular function through a negative feedback loop.

Keywords: Protein phosphorylation, tyrosine-kinase, Streptoccus pneumoniae, cell growth, ATP hydrolysis, cell morphogenesis

Received: 07 Jun 2019; Accepted: 07 Aug 2019.

Copyright: © 2019 Pelletier, Freton, Gallay, Trouvé, Cluzel, Franz-Watchel, Macek, Jault, Grangeasse and GUIRAL. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Dr. Christophe Grangeasse, UMR5086 Microbiologie Moléculaire et Biochimie Structurale (MMSB), Lyon, 69367, Rhône-Alpes, France,
Dr. Sébastien GUIRAL, Université de Lyon, Molecular Microbiology and Structural Biochemistry - UMR5086, Lyon, France,