Metabolic coupling of plastidic and cytosolic pools of low-molecular weight thiols via members of the CRT-like transporter (CLT) family

通过类 CRT 转运蛋白 (CLT) 家族成员实现低分子量硫醇质体和胞质池的代谢耦合

• 批准号: 180855839
• 负责人: Professor Dr. Andreas Meyer
• 金额: --
• 依托单位: Arbeitsgruppe Chemical Signalling
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2013-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/180855839?language=en
• 关键词: Metabolic; coupling; plastidic; cytosolic; pools

Glutathione is the most abundant low molecular weight thiol in virtually all living organisms and has essential functions in cellular redox homeostasis and environmental signaling. In Arabidopsis thaliana, the two step biosynthetic pathway for glutathione is compartmentalized between plastids and cytosol with the first enzyme, glutamate-cysteine ligase (GSH1), being localized exclusively in the plastids and the second enzyme, glutathione synthase (GSH2), being expressed in both compartments. Coupling of the two glutathione pools is mediated by the recently identified chloroquine-resistance transporter like transporters (CLTs), which are the first functionally characterized members of the plant drug/metabolite exporter family. In this project, the protein structure and the characterization of the transport properties of all three Arabidopsis CLTs will be investigated in vivo as well as in vitro in heterologous expression systems and reconstituted liposomes. The in vivo function of CLTs for bidirectional transport between plastids and cytosol will be analyzed through compartment-specific reconstitution of the glutathione biosynthetic pathway in a mutant background. Misexpression of GSH1 in the cytosol will also provide novel information about the regulation of GSH1 activity. In vivo imaging of the glutathione redox potential with redoxsensitive GFP probes will further resolve the dynamics of the glutathione redox buffer under exposure to abiotic and biotic stress at subcellular level and help elucidating the role of glutathione in activating the immune response in plants.

谷胱甘肽是几乎所有生物体中含量最多的低分子量硫醇，在细胞氧化还原稳态和环境信号传导中具有重要作用。在拟南芥中，谷胱甘肽的两步生物合成途径被划分在质体和细胞质之间，第一种酶谷氨酸-半胱氨酸连接酶（GSH1）只定位于质体，第二种酶谷胱甘肽合成酶（GSH2）在两个区室中表达。两个谷胱甘肽库的耦合是由最近发现的抗氯喹转运蛋白样转运蛋白（CLTs）介导的，这是植物药物/代谢物出口家族中第一个功能表征的成员。在本项目中，将在体内以及体外异种表达系统和重组脂质体中研究所有三种拟南芥clt的蛋白质结构和运输特性。通过突变背景下谷胱甘肽生物合成途径的室特异性重构，将分析CLTs在质体和细胞质间双向运输的体内功能。细胞质中GSH1的错误表达也将提供关于GSH1活性调控的新信息。利用氧化还原敏感的GFP探针对谷胱甘肽氧化还原电位进行体内成像，将进一步在亚细胞水平上解决暴露于非生物和生物胁迫下谷胱甘肽氧化还原缓冲液的动力学问题，并有助于阐明谷胱甘肽在激活植物免疫应答中的作用。