A tryparedoxin-coupled biosensor reveals a mitochondrial trypanothione metabolism in trypanosomes
A tryparedoxin-coupled biosensor reveals a mitochondrial trypanothione metabolism in trypanosomes
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DOI：
10.7554/elife.53227
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发表时间：
2020-01-31
期刊：
影响因子：
7.7
通讯作者：
Krauth-Siegel, R. Luise
中科院分区：
文献类型：
--
作者：
Ebersoll, Samantha;Bogacz, Marta;Krauth-Siegel, R. Luise
锥虫具有锥虫硫酮氧化还原代谢，其为许多基本过程提供还原当量，大多数由锥虫氧还蛋白（Tpx）介导。虽然锥虫硫酮的生物合成和还原是胞质的，但这些寄生虫的单细胞中硫醇氧化还原稳态的分子基础在很大程度上仍然未知。在此，我们在布氏锥虫的胞浆或胞浆中表达了Tpx-roGFP 2、roGFP 2-hGrx 1或roGFP 2。我们表明，新的Tpx-roGFP 2是一个上级探针锥虫硫酮氧化还原对和线粒体基质窝藏锥虫硫酮系统。通过抗锥虫药物依氟鸟氨酸抑制锥虫硫酮的生物合成损害了胞质溶胶和胞内体科普外源性氧化应激的能力，表明两种巯基系统之间存在直接联系。Tpx耗竭消除了胞质，但仅部分影响线粒体传感器对H2 O2的响应。这有力地表明，该蛋白含有一些Tpx和另一种尚未鉴定的氧化还原酶。
Trypanosomes have a trypanothione redox metabolism that provides the reducing equivalents for numerous essential processes, most being mediated by tryparedoxin (Tpx). While the biosynthesis and reduction of trypanothione are cytosolic, the molecular basis of the thiol redox homeostasis in the single mitochondrion of these parasites has remained largely unknown. Here we expressed Tpx-roGFP2, roGFP2-hGrx1 or roGFP2 in either the cytosol or mitochondrion of Trypanosoma brucei. We show that the novel Tpx-roGFP2 is a superior probe for the trypanothione redox couple and that the mitochondrial matrix harbors a trypanothione system. Inhibition of trypanothione biosynthesis by the anti-trypanosomal drug Eflornithine impairs the ability of the cytosol and mitochondrion to cope with exogenous oxidative stresses, indicating a direct link between both thiol systems. Tpx depletion abolishes the cytosolic, but only partially affects the mitochondrial sensor response to H2O2. This strongly suggests that the mitochondrion harbors some Tpx and, another, as yet unidentified, oxidoreductase.