Two essential Thioredoxins mediate apicoplast biogenesis, protein import, and gene expression in Toxoplasma gondii.
Two essential Thioredoxins mediate apicoplast biogenesis, protein import, and gene expression in Toxoplasma gondii.
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DOI：
10.1371/journal.ppat.1006836
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发表时间：
2018-03
期刊：
影响因子：
6.7
通讯作者：
Sheiner L
中科院分区：
文献类型：
--
作者：
Biddau M;Bouchut A;Major J;Saveria T;Tottey J;Oka O;van-Lith M;Jennings KE;Ovciarikova J;DeRocher A;Striepen B;Waller RF;Parsons M;Sheiner L
顶复门寄生虫是全球杀手，是弓形虫病和疟疾等疾病的病原体。已知这些寄生虫对氧化还原失衡过敏，但对其各种氧化还原调节剂的细胞作用知之甚少。顶质体是一种重要的质体细胞器，是顶复体的药物靶点。核编码的顶质体蛋白通过内质网和多个顶质体亚区室运输到它们的功能位置。我们建议，硫氧还蛋白有助于控制蛋白质运输和蛋白质功能在这些顶质体车厢。我们研究了两个弓形虫apicoplast硫氧还蛋白（TgATdoxins）的作用，都是寄生虫生存所必需的。通过描述这些氧化还原调节酶的条件性耗竭的细胞表型，我们表明它们中的每一个都有助于不同的顶质体生物发生途径。我们提供的证据TgATrx1的参与ER顶质体贩运和TgATrx2顶质体基因表达组件的控制。底物下拉进一步识别与TgATrx2相互作用的基因表达因子。我们使用遗传互补来证明这两个TgATrxs的功能是依赖于它们的二硫化物交换活性。最后，TgATrx2与人硫氧还蛋白不同。我们证明了其在体外的活性，从而为药物筛选提供了范围。我们的研究代表了弓形虫中硫氧还蛋白的第一个功能特征，突出了顶质体功能的氧化还原调节的重要性，并提供了新的工具来研究这些寄生虫中的氧化还原生物学。为了生存，顶复门寄生虫必须适应它们所经历的氧化还原损伤。这些寄生虫经历由它们生活的宿主细胞、宿主免疫系统和它们自身的代谢活动诱导的氧化还原应激。然而，受氧化还原变化影响并可能参与维持寄生虫体内氧化还原平衡的无数细胞过程在很大程度上未得到充分研究。硫氧还蛋白是将亚细胞环境的氧化还原状态与其底物蛋白的功能状态或细胞运输联系起来的酶。在这项工作中，我们确定了两个途径，由两个硫氧还蛋白在apicomplexan弓形虫控制，并证明这两个是必不可少的寄生虫生存。我们表明，这些酶的每一个有助于顶复体的质体，顶质体，一个独特的寄生虫细胞器的功能与药物发现工作的重要性。因此，我们强调，apicomplexan的氧化还原失衡的敏感性的一部分是特别相关的apicoplast，并在介导apicoplast生物发生的重要性的硫氧还蛋白点。最后，我们的工作提高了顶质体硫氧还蛋白作为新药物靶点的潜力。
Apicomplexan parasites are global killers, being the causative agents of diseases like toxoplasmosis and malaria. These parasites are known to be hypersensitive to redox imbalance, yet little is understood about the cellular roles of their various redox regulators. The apicoplast, an essential plastid organelle, is a verified apicomplexan drug target. Nuclear-encoded apicoplast proteins traffic through the ER and multiple apicoplast sub-compartments to their place of function. We propose that thioredoxins contribute to the control of protein trafficking and of protein function within these apicoplast compartments. We studied the role of two Toxoplasma gondii apicoplast thioredoxins (TgATrx), both essential for parasite survival. By describing the cellular phenotypes of the conditional depletion of either of these redox regulated enzymes we show that each of them contributes to a different apicoplast biogenesis pathway. We provide evidence for TgATrx1’s involvement in ER to apicoplast trafficking and TgATrx2 in the control of apicoplast gene expression components. Substrate pull-down further recognizes gene expression factors that interact with TgATrx2. We use genetic complementation to demonstrate that the function of both TgATrxs is dependent on their disulphide exchange activity. Finally, TgATrx2 is divergent from human thioredoxins. We demonstrate its activity in vitro thus providing scope for drug screening. Our study represents the first functional characterization of thioredoxins in Toxoplasma, highlights the importance of redox regulation of apicoplast functions and provides new tools to study redox biology in these parasites. To survive, apicomplexan parasites must adjust to the redox insults they experience. These parasites undergo redox stresses induced by the host cell within which they live, by the host immune system, and by their own metabolic activities. Yet the myriad of cellular processes that are affected by redox changes and that may take part in maintaining the redox balance within the parasite are largely understudied. Thioredoxins are enzymes that link the redox state of subcellular environments to the functional state or the cellular trafficking of their substrate proteins. In this work, we identify two pathways that are controlled by two thioredoxins in the apicomplexan Toxoplasma gondii, and demonstrate that both are essential for parasite survival. We show that each of these enzymes contributes to the function of the apicomplexan plastid, the apicoplast, a unique parasite organelle with importance for drug discovery efforts. We thus highlight that part of the apicomplexan sensitivity to redox imbalance is specifically related to the apicoplast, and point at the importance of thioredoxins in mediating apicoplast biogenesis. Finally, our work raises the potential of apicoplast thioredoxins as new drug targets.
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影响因子：
48
作者：
Andenmatten, Nicole;Egarter, Saskia;Jackson, Allison J;Jullien, Nicolas;Herman, Jean-Paul;Meissner, Markus
通讯作者：
Meissner, Markus
影响因子：
11.4
作者：
Jessop, Catherine E.;Chakravarthi, Seema;Bulleid, Neil J.
通讯作者：
Bulleid, Neil J.
影响因子：
4.8
作者：
Hanson, GT;Aggeler, R;Remington, SJ
通讯作者：
Remington, SJ
影响因子：
4.8
作者：
Agrawal, Swati;van Dooren, Giel G.;Striepen, Boris
通讯作者：
Striepen, Boris
DOI：
10.1073/pnas.232703799
发表时间：
2003-01-07
影响因子：
11.1
作者：
Balmer, Y;Koller, A;Buchanan, BB
通讯作者：
Buchanan, BB