Phosphatidylserine synthase 2 and phosphatidylserine decarboxylase are essential for aminophospholipid synthesis in Trypanosoma brucei.
Phosphatidylserine synthase 2 and phosphatidylserine decarboxylase are essential for aminophospholipid synthesis in Trypanosoma brucei.
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DOI：
10.1111/mmi.13637
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发表时间：
2017-05
影响因子：
3.6
通讯作者：
Bütikofer P
中科院分区：
文献类型：
--
作者：
Farine L;Jelk J;Choi JY;Voelker DR;Nunes J;Smith TK;Bütikofer P
磷脂酰乙醇胺 (PE) 和磷脂酰丝氨酸 (PS) 是真核生物和原核生物中普遍表达且代谢相互关联的甘油磷脂。在布氏锥虫中，PE 合成已被证明主要通过肯尼迪途径发生，肯尼迪途径是真核生物中 PE 合成的三种途径之一，而 PS 合成尚未经过实验研究。我们现在揭示了布氏锥虫 PS 合酶 2 (TbPSS2) 和布氏锥虫 PS 脱羧酶 (TbPSD) 这两种参与氨基磷脂合成的关键酶对于锥虫活力的重要性。通过使用四环素诱导的基因表达下调以及体内和体外代谢标记，我们发现TbPSS2（i）对于原环锥虫的正常生长是必需的，（ii）定位于内质网，并且（iii）代表了布氏锥虫中PS形成的独特途径。此外，我们将 TbPSD 鉴定为线粒体中的 I 型 PS 脱羧酶，并发现它在 WGSS 切割位点被蛋白水解加工成异二聚体。 TbPSD 表达的下调影响了原环锥虫和血流形式锥虫中的线粒体完整性，通过原环形式的氧化磷酸化减少了 ATP 的产生，并影响了寄生虫的生长。
Phosphatidylethanolamine (PE) and phosphatidylserine (PS) are ubiquitously expressed and metabolically interconnected glycerophospholipids in eukaryotes and prokaryotes. In Trypanosoma brucei, PE synthesis has been shown to occur mainly via the Kennedy pathway, one of the three routes leading to PE synthesis in eukaryotes, while PS synthesis has not been studied experimentally. We now reveal the importance of T. brucei PS synthase 2 (TbPSS2) and T. brucei PS decarboxylase (TbPSD), two key enzymes involved in aminophospholipid synthesis, for trypanosome viability. By using tetracycline‐inducible down‐regulation of gene expression and in vivo and in vitro metabolic labeling, we found that TbPSS2 (i) is necessary for normal growth of procyclic trypanosomes, (ii) localizes to the endoplasmic reticulum and (iii) represents the unique route for PS formation in T. brucei. In addition, we identified TbPSD as type I PS decarboxylase in the mitochondrion and found that it is processed proteolytically at a WGSS cleavage site into a heterodimer. Down‐regulation of TbPSD expression affected mitochondrial integrity in both procyclic and bloodstream form trypanosomes, decreased ATP production via oxidative phosphorylation in procyclic form and affected parasite growth.