The regulatory function of the plant cysteine synthase protein complex for cellular cysteine homeostasis

植物半胱氨酸合酶蛋白复合物对细胞半胱氨酸稳态的调节功能

基本信息

批准号：
115487487
负责人：
Professor Dr. Rüdiger Hell
金额：
--
依托单位：
Centre for Organismal Studies (COS)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2009
资助国家：
德国
起止时间：
2008-12-31 至 2014-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/115487487?language=en
关键词：
regulatory function plant cysteine synthase

项目摘要

Cysteine synthesis provides the only entry of assimilated sulfur into plant metabolism and forms one essential step for human and animal nutrition. Biochemical evidence suggests that cellular homeostasis of cysteine in plants is controlled by a unique sensing mechanism and subcellular organisation. The hetero-oligomeric cysteine synthase protein complex is located in cytosol, plastids and mitochondria. Its reversible activation/inactivation depends on whether its subunits are inside or outside the complex and this equilibrium is determined by the inverse effects of the pathway intermediates sulfide and O-acetylserine. The central function of the cysteine synthase complex will be addressed in two independent approaches. One, the reversible association of the complex and its response to changes in homeostasis will be investigated in vivo using fluorescence resonance energy transfer (FRET). Two, artificial microRNA interference and T-DNA mutants will be used to evaluate the hypothesis that mitochondria, and not plastids, are most important for the rate of cysteine synthesis. The results will clarify the current hypothesis of dynamic flux control by the cysteine synthase complex and unravel the role of cellular compartments in cysteine homeostasis. They will be significant for understanding of regulatory protein interactions in metabolism in general.

半胱氨酸合成提供了同化硫的唯一进入植物代谢，并构成了人类和动物营养的重要步骤。生化证据表明，植物中半胱氨酸的细胞稳态受到独特的感应机制和亚细胞组织的控制。杂聚糖半胱氨酸合酶蛋白复合物位于细胞质，质体和线粒体中。它的可逆激活/灭活取决于其亚基是在复合物内还是外部，并且该平衡取决于途径中间体硫化物和o-乙酰基丝氨酸的反反应。半胱氨酸合酶络合物的中心功能将以两种独立的方法来解决。第一，将使用荧光共振能量转移（FRET）研究该复合物的可逆关联及其对体内平衡变化的反应。二，人工microRNA干扰和T-DNA突变体将用于评估线粒体而非质体的假设对于半胱氨酸合成速率最为重要。结果将阐明半胱氨酸合酶复合物对动态通量控制的当前假设，并揭示细胞隔室在半胱氨酸稳态中的作用。它们对于一般的代谢中的调节蛋白相互作用将非常重要。