Triacylglycerol Storage in Lipid Droplets in Procyclic Trypanosoma brucei.
Triacylglycerol Storage in Lipid Droplets in Procyclic Trypanosoma brucei.
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布鲁氏锥虫中的脂质液滴中的三酰基甘油储存。
DOI：
10.1371/journal.pone.0114628
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
Boshart M
中科院分区：
文献类型：
--
作者：
Allmann S;Mazet M;Ziebart N;Bouyssou G;Fouillen L;Dupuy JW;Bonneu M;Moreau P;Bringaud F;Boshart M
碳储存可能使锥虫能够适应采采蝇阶段发育和迁徙期间的营养挑战或瓶颈。脂滴是这种功能的候选者。该报告显示，通过共聚焦荧光显微镜和 BODIPY 493/503 染色细胞的流式细胞术进行定量，用油酸喂养布氏锥虫会导致脂滴数量增加 4-5 倍。三酰甘油（TAG）含量也增加了4-5倍，并且标记的油酸酯被掺入TAG中。因此，在原环T. brucei的生理生长条件下，脂肪酸碳可以作为TAG储存在脂滴中。 β-氧化被认为是布氏锥虫中脂质可能的分解代谢途径。鉴定出具有三功能酶复合物亚基编码能力的单个候选基因 TFEα1。 TFEα1 在原环布氏锥虫中表达，并存在于糖体蛋白质组中。出乎意料的是，TFEα1 基因敲除突变体仍然表达野生型水平的先前报道的 NADP 依赖性 3-羟酰基辅酶 A 脱氢酶活性，因此，另一个基因编码这种酶活性。纯合 Δtfeα1/Δtfeα1 无效突变细胞在原环布氏锥虫中显示出正常的生长速率和未改变的糖体蛋白质组。油酸撤出后积累的脂滴的衰减动力学可以完全通过野生型和 Δtfeα1/Δtfeα1 细胞中细胞分裂的稀释效应来解释。即使在严格无葡萄糖的条件下，前环T. brucei中储存的TAG也不存在净分解代谢，这并不正式排除通过TAG的通量，其中生物合成等于分解代谢。此外，TAG 分解代谢仍然有可能被培养基中的其他碳源完全抑制，或者在采采蝇的后循环阶段发育激活。
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.
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影响因子：
7.4
作者：
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通讯作者：
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影响因子：
2.4
作者：
Ebikeme, C. E.;Peacock, L.;Barrett, M. P.
通讯作者：
Barrett, M. P.