1
|
Leiba J, Syson K, Baronian G, Zanella-Cléon I, Kalscheuer R, Kremer L, Bornemann S, Molle V. Mycobacterium tuberculosis maltosyltransferase GlgE, a genetically validated antituberculosis target, is negatively regulated by Ser/Thr phosphorylation. J Biol Chem 2013; 288:16546-16556. [PMID: 23609448 DOI: 10.1074/jbc.m112.398503] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
GlgE is a maltosyltransferase involved in the biosynthesis of α-glucans that has been genetically validated as a potential therapeutic target against Mycobacterium tuberculosis. Despite also making α-glucan, the GlgC/GlgA glycogen pathway is distinct and allosterically regulated. We have used a combination of genetics and biochemistry to establish how the GlgE pathway is regulated. M. tuberculosis GlgE was phosphorylated specifically by the Ser/Thr protein kinase PknB in vitro on one serine and six threonine residues. Furthermore, GlgE was phosphorylated in vivo when expressed in Mycobacterium bovis bacillus Calmette-Guérin (BCG) but not when all seven phosphorylation sites were replaced by Ala residues. The GlgE orthologues from Mycobacterium smegmatis and Streptomyces coelicolor were phosphorylated by the corresponding PknB orthologues in vitro, implying that the phosphorylation of GlgE is widespread among actinomycetes. PknB-dependent phosphorylation of GlgE led to a 2 orders of magnitude reduction in catalytic efficiency in vitro. The activities of phosphoablative and phosphomimetic GlgE derivatives, where each phosphorylation site was substituted with either Ala or Asp residues, respectively, correlated with negative phosphoregulation. Complementation studies of a M. smegmatis glgE mutant strain with these GlgE derivatives, together with both classical and chemical forward genetics, were consistent with flux through the GlgE pathway being correlated with GlgE activity. We conclude that the GlgE pathway appears to be negatively regulated in actinomycetes through the phosphorylation of GlgE by PknB, a mechanism distinct from that known in the classical glycogen pathway. Thus, these findings open new opportunities to target the GlgE pathway therapeutically.
Collapse
Affiliation(s)
- Jade Leiba
- 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
| | - Karl Syson
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom
| | - Grégory Baronian
- 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
| | - Isabelle Zanella-Cléon
- 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
| | - Rainer Kalscheuer
- Institute for Medical Microbiology and Hospital Hygiene, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Laurent Kremer
- 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; INSERM, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France
| | - Stephen Bornemann
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom.
| | - Virginie Molle
- 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.
| |
Collapse
|