title: Characterisation of polyglutamylases in trypanosomatids.
abstract: Microtubules are subject to post-translational modifications, which are thought to have crucial roles in the function of complex microtubule-based organelles. Among these, polyglutamylation was relatively recently discovered, and was related to centrosome stability, axonemal maintenance and mobility, and neurite outgrowth. In trypanosomatids, parasitic protozoa where microtubules constitute the essential component of the cytoskeleton, the function of polyglutamylated microtubules is unknown. Here, in order to better understand the role of this conserved but highly divergent post-translational modification, we characterised glutamylation and putative polyglutamylases in these parasites. We showed that microtubules are intensely glutamylated in all stages of the cell cycle, including interphase. Moreover, a cell cycle-dependent gradient of glutamylation was observed along the cell anteroposterior axis, which might be related to active growth of the microtubule 'corset' during the cell cycle. We also identified two putative polyglutamylase proteins (among seven analysed here) which appeared to be clearly and directly involved in microtubule polyglutamylation in in vitro activity assays. Paradoxically, in view of the importance of tubulins and of their extensive glutamylation in these organisms, RNA interference-based knockdown of all these proteins had no effect on cell growth, suggesting either functional redundancy or, more likely, subtle roles such as function modulation or interaction with protein partners.
authors.affiliation: Centre National de la Recherche Scientifique (CNRS), 5290-IRD 224-University Montpellier 1, Research Unit "MIVEGEC", Montpellier, France.
authors.forename: Magali
authors.initials: M
authors.lastname: Casanova
authors.affiliation: Centre National de la Recherche Scientifique (CNRS), 5290-IRD 224-University Montpellier 1, Research Unit "MIVEGEC", Montpellier, France.
authors.forename: Frédérique
authors.initials: F
authors.lastname: de Monbrison
authors.affiliation: CNRS UMR 5237 - University Montpellier 2 and 1, Research Unit "Centre de Recherche de Biochimie Macromoléculaire", Montpellier, France.
authors.forename: Juliette
authors.initials: J
authors.lastname: van Dijk
authors.affiliation: CNRS UMR 5237 - University Montpellier 2 and 1, Research Unit "Centre de Recherche de Biochimie Macromoléculaire", Montpellier, France.
authors.forename: Carsten
authors.initials: C
authors.lastname: Janke
authors.affiliation: Centre National de la Recherche Scientifique (CNRS), 5290-IRD 224-University Montpellier 1, Research Unit "MIVEGEC", Montpellier, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Pagès
authors.affiliation: Centre National de la Recherche Scientifique (CNRS), 5290-IRD 224-University Montpellier 1, Research Unit "MIVEGEC", Montpellier, France; CHU (Hospital University Centre) of Montpellier and University Montpellier 1 (Faculty of Medicine), Laboratoire de Parasitologie-Mycologie, Montpellier, France. Electronic address: patrick.bastien@univ-montp1.fr.
authors.forename: Patrick
authors.initials: P
authors.lastname: Bastien
mesh_terms: D002453:Cell Cycle; D002470:Cell Survival; D055785:Gene Knockdown Techniques; D008870:Microtubules / Q000502:physiology*; D010453:Peptide Synthases / Q000235:genetics / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D014345:Trypanosoma / Q000201:enzymology* / Q000378:metabolism / Q000502:physiology*; D014404:Tubulin / Q000378:metabolism*
chemical_list: D014404:Tubulin; D010453:Peptide Synthases; C112698:tubulin polyglutamylase
keywords: Glutamylation; Leishmania major; Microtubules; Polyglutamylases; Trypanosoma brucei; Tubulin Tyrosine Ligase-Like