title: Triacylglycerol Storage in Lipid Droplets in Procyclic Trypanosoma brucei.
abstract: Carbon storage is likely to enable adaptation of trypanosomes to nutritional challenges or bottlenecks during their stage development and migration in the tsetse. Lipid droplets are candidates for this function. This report shows that feeding of T. brucei with oleate results in a 4-5 fold increase in the number of lipid droplets, as quantified by confocal fluorescence microscopy and by flow cytometry of BODIPY 493/503-stained cells. The triacylglycerol (TAG) content also increased 4-5 fold, and labeled oleate is incorporated into TAG. Fatty acid carbon can thus be stored as TAG in lipid droplets under physiological growth conditions in procyclic T. brucei. β-oxidation has been suggested as a possible catabolic pathway for lipids in T. brucei. A single candidate gene, TFEα1 with coding capacity for a subunit of the trifunctional enzyme complex was identified. TFEα1 is expressed in procyclic T. brucei and present in glycosomal proteomes, Unexpectedly, a TFEα1 gene knock-out mutant still expressed wild-type levels of previously reported NADP-dependent 3-hydroxyacyl-CoA dehydrogenase activity, and therefore, another gene encodes this enzymatic activity. Homozygous Δtfeα1/Δtfeα1 null mutant cells show a normal growth rate and an unchanged glycosomal proteome in procyclic T. brucei. The decay kinetics of accumulated lipid droplets upon oleate withdrawal can be fully accounted for by the dilution effect of cell division in wild-type and Δtfeα1/Δtfeα1 cells. The absence of net catabolism of stored TAG in procyclic T. brucei, even under strictly glucose-free conditions, does not formally exclude a flux through TAG, in which biosynthesis equals catabolism. Also, the possibility remains that TAG catabolism is completely repressed by other carbon sources in culture media or developmentally activated in post-procyclic stages in the tsetse.
authors.affiliation: Fakultät für Biologie, Genetik, Ludwig-Maximilians-Universität München, Biozentrum, Martinsried, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Allmann
authors.affiliation: Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), Unité Mixte de Recherche 5536, Université de Bordeaux/Centre National de la Recherche Scientifique (CNRS), Bordeaux, France.
authors.forename: Muriel
authors.initials: M
authors.lastname: Mazet
authors.affiliation: Fakultät für Biologie, Genetik, Ludwig-Maximilians-Universität München, Biozentrum, Martinsried, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Ziebart
authors.affiliation: Laboratoire de Biogenèse Membranaire, Unité Mixte de Recherche 5200, Université de Bordeaux/Centre National de la Recherche Scientifique (CNRS), Institut National de la Recherche Agronomique (INRA) Bordeaux, Villenave d'Ornon, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Bouyssou
authors.affiliation: Laboratoire de Biogenèse Membranaire, Unité Mixte de Recherche 5200, Université de Bordeaux/Centre National de la Recherche Scientifique (CNRS), Institut National de la Recherche Agronomique (INRA) Bordeaux, Villenave d'Ornon, France.
authors.forename: Laetitia
authors.initials: L
authors.lastname: Fouillen
authors.affiliation: Centre de Génomique Fonctionnelle, Plateforme Protéome, Université de Bordeaux, Bordeaux, France.
authors.forename: Jean-William
authors.initials: JW
authors.lastname: Dupuy
authors.affiliation: Centre de Génomique Fonctionnelle, Plateforme Protéome, Université de Bordeaux, Bordeaux, France.
authors.forename: Marc
authors.initials: M
authors.lastname: Bonneu
authors.affiliation: Laboratoire de Biogenèse Membranaire, Unité Mixte de Recherche 5200, Université de Bordeaux/Centre National de la Recherche Scientifique (CNRS), Institut National de la Recherche Agronomique (INRA) Bordeaux, Villenave d'Ornon, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Moreau
authors.affiliation: Centre de Résonance Magnétique des Systèmes Biologiques (RMSB), Unité Mixte de Recherche 5536, Université de Bordeaux/Centre National de la Recherche Scientifique (CNRS), Bordeaux, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Bringaud
authors.affiliation: Fakultät für Biologie, Genetik, Ludwig-Maximilians-Universität München, Biozentrum, Martinsried, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Boshart
mesh_terms: D015139:Blotting, Southern; D005434:Flow Cytometry; D017125:Genes, Protozoan / Q000235:genetics / Q000502:physiology; D050356:Lipid Metabolism; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D019301:Oleic Acid / Q000378:metabolism; D010802:Phylogeny; D014280:Triglycerides / Q000378:metabolism*; D014346:Trypanosoma brucei brucei / Q000235:genetics / Q000378:metabolism*
chemical_list: D014280:Triglycerides; D019301:Oleic Acid