RESEARCH ARTICLE Triacylglycerol Storage in Lipid Droplets in

Carbon storage is likely to enable adaptation of trypanosomes to nutritional challenges or bottlenecks during their stage development andmigration 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. b-oxidation has been suggested as a possible catabolic pathway for lipids in T. brucei. A single candidate gene, TFEa1 with coding capacity for a subunit of the trifunctional enzyme complex was identified. TFEa1 is expressed in procyclic T. brucei and present in glycosomal proteomes, Unexpectedly, a TFEa1 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 Dtfea1/Dtfea