Inhibition of TOR in Chlamydomonas reinhardtii Leads to Rapid Cysteine Oxidation Reflecting Sustained Physiological Changes
Inhibition of TOR in Chlamydomonas reinhardtii Leads to Rapid Cysteine Oxidation Reflecting Sustained Physiological Changes
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DOI：
10.3390/cells8101171
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发表时间：
2019-10-01
期刊：
影响因子：
6
通讯作者：
Hicks, Leslie M.
中科院分区：
文献类型：
--
作者：
Ford, Megan M.;Smythers, Amanda L.;Hicks, Leslie M.
雷帕霉素（TOR）激酶的靶点是一种主要的代谢调节剂，在营养传感、蛋白质翻译和自噬中发挥作用。在莱茵衣藻（一种单细胞绿色真菌）中，TOR与增加的三酰甘油（TAG）积累的调节有关，表明TOR或下游靶标负责在营养限制下控制增加的TAG积累的难以捉摸的“脂质开关”。然而，虽然TOR在哺乳动物系统中已得到很好的表征，但在光合系统中仍然知之甚少，并且几乎没有工作表明氧化信号在TOR调节中的作用。在这项研究中，TOR抑制剂AZD 8055用于将可逆的巯基氧化与TOR抑制下观察到的生理变化（包括TAG含量增加）联系起来。使用氧化半胱氨酸树脂辅助捕获富集结合无标记定量蛋白质组学，确定401种蛋白质在TOR抑制后具有显著的氧化变化。这些氧化变化反映了表征的生理修饰，通过使用可逆硫醇氧化支持可逆硫醇氧化在TAG产生、蛋白质翻译、碳水化合物催化和光合作用的TOR调节中的作用。TOR抑制下氧化还原控制蛋白的描绘为进一步表征光合真核生物中TOR途径提供了框架。
The target of rapamycin (TOR) kinase is a master metabolic regulator with roles in nutritional sensing, protein translation, and autophagy. In Chlamydomonas reinhardtii, a unicellular green alga, TOR has been linked to the regulation of increased triacylglycerol (TAG) accumulation, suggesting that TOR or a downstream target(s) is responsible for the elusive "lipid switch" in control of increasing TAG accumulation under nutrient limitation. However, while TOR has been well characterized in mammalian systems, it is still poorly understood in photosynthetic systems, and little work has been done to show the role of oxidative signaling in TOR regulation. In this study, the TOR inhibitor AZD8055 was used to relate reversible thiol oxidation to the physiological changes seen under TOR inhibition, including increased TAG content. Using oxidized cysteine resin-assisted capture enrichment coupled with label-free quantitative proteomics, 401 proteins were determined to have significant changes in oxidation following TOR inhibition. These oxidative changes mirrored characterized physiological modifications, supporting the role of reversible thiol oxidation in TOR regulation of TAG production, protein translation, carbohydrate catabolism, and photosynthesis through the use of reversible thiol oxidation. The delineation of redox-controlled proteins under TOR inhibition provides a framework for further characterization of the TOR pathway in photosynthetic eukaryotes.