Phosphorylation of InhA inhibits mycolic acid biosynthesis and growth of Mycobacterium tuberculosis

Authors

  • Virginie Molle,

    Corresponding author
    1. Institut de Biologie et Chimie des Protéines (IBCP UMR 5086), CNRS, Université Lyon1, IFR128 BioSciences, Lyon-Gerland, 7 passage du Vercors, 69367 Lyon Cedex 07, France.
      E-mail vmolle@ibcp.fr; Tel. (+33) 4 72 72 26 79; Fax (+33) 4 72 72 26 41;
    Search for more papers by this author
    • Present address: Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Universités de Montpellier II et I, CNRS; UMR 5235, case 107, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France.

    • Equal contribution of the first two authors.

  • Gulcin Gulten,

    1. Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA.
    Search for more papers by this author
    • Equal contribution of the first two authors.

  • Catherine Vilchèze,

    1. Howard Hughes Medical Institute, Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA.
    Search for more papers by this author
  • Romain Veyron-Churlet,

    1. Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Universités de Montpellier II et I, CNRS; UMR 5235, case 107, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France.
    Search for more papers by this author
  • Isabelle Zanella-Cléon,

    1. Institut de Biologie et Chimie des Protéines (IBCP UMR 5086), CNRS, Université Lyon1, IFR128 BioSciences, Lyon-Gerland, 7 passage du Vercors, 69367 Lyon Cedex 07, France.
    Search for more papers by this author
  • James C. Sacchettini,

    1. Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA.
    Search for more papers by this author
  • William R. Jacobs Jr,

    1. Howard Hughes Medical Institute, Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA.
    Search for more papers by this author
  • Laurent Kremer

    Corresponding author
    1. Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, Universités de Montpellier II et I, CNRS; UMR 5235, case 107, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France.
    2. INSERM, DIMNP, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France.
      E-mail laurent.kremer@univ-montp2.fr; Tel. (+33) 4 67 14 33 81; Fax (+33) 4 67 14 42 86.
    Search for more papers by this author

E-mail vmolle@ibcp.fr; Tel. (+33) 4 72 72 26 79; Fax (+33) 4 72 72 26 41;

E-mail laurent.kremer@univ-montp2.fr; Tel. (+33) 4 67 14 33 81; Fax (+33) 4 67 14 42 86.

Summary

The remarkable survival ability of Mycobacterium tuberculosis in infected hosts is related to the presence of cell wall-associated mycolic acids. Despite their importance, the mechanisms that modulate expression of these lipids in response to environmental changes are unknown. Here we demonstrate that the enoyl-ACP reductase activity of InhA, an essential enzyme of the mycolic acid biosynthetic pathway and the primary target of the anti-tubercular drug isoniazid, is controlled via phosphorylation. Thr-266 is the unique kinase phosphoacceptor, both in vitro and in vivo. The physiological relevance of Thr-266 phosphorylation was demonstrated using inhA phosphoablative (T266A) or phosphomimetic (T266D/E) mutants. Enoyl reductase activity was severely impaired in the mimetic mutants in vitro, as a consequence of a reduced binding affinity to NADH. Importantly, introduction of inhA_T266D/E failed to complement growth and mycolic acid defects of an inhA-thermosensitive Mycobacterium smegmatis strain, in a similar manner to what is observed following isoniazid treatment. This study suggests that phosphorylation of InhA may represent an unusual mechanism that allows M. tuberculosis to regulate its mycolic acid content, thus offering a new approach to future anti-tuberculosis drug development.

Ancillary