Reciprocal regulation of chloroplast protein synthesis and carbon metabolism for thylakoid membrane biogenesis

类囊体膜生物发生中叶绿体蛋白质合成和碳代谢的相互调节

• 批准号: 241420340
• 负责人: Professor Dr. Jörg Nickelsen, Ph.D.
• 金额: --
• 依托单位: Arbeitsgruppe Molekulare Pflanzenwissenschaften
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2017-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/241420340?language=en
• 关键词: Reciprocal; regulation; chloroplast; protein; synthesis

Thylakoid membranes represent highly developed sites for photosynthetic energy transduction. Their biogenesis requires the synthesis of both lipids as well as proteins. However, little is known regarding if and how these two biosynthetic pathways are interconnected at the molecular level. The chloroplast pyruvate dehydrogenase complex is well-known to produce activated di-carbon precursor molecules (acetyl-CoA) for fatty acid - and as a consequence - lipid synthesis. Our prework shows that the DLA2 subunit of this enzyme is additionally a component of a ribonculeoprotein complex and as this has a function in the spatial organization of chloroplast mRNA translation in the green algal model system Chlamydomonas reinhardtii. Conversely, RNA binding affects pyruvate dehydrogenase activity. These findings provide a first clue regarding how intraplastidic metabolic signaling and chloroplast gene expression could be reciprocally connected for thylakoid membrane biogenesis. In addition, our data provide first hints that these dual roles of the protein might exist in evolutionary distant organisms ranging from cyanobacteria to humans.In this project, we aim at elucidating the precise molecular working mode of this regulatory principle involving metabolic control of gene expression. By following molecular, genetical, and biochemical approaches in C. reinhardtii, we will use in vivo and in vitro techniques to characterize both the RNA binding and the enzymatic forms of DLA2 which appears to shuttle between different protein sub-complexes. A special focus will be on the dynamics and composition of these complexes and the role of acetate/acetyl-CoA for balancing both functions of DLA2. This work will be complemented by related analyses in cyanobacteria and higher plants, to test for an evolutionary conservation of such a regulatory switch.

类囊体膜代表了高度发达的光合作用能量转换位点。它们的生物发生需要脂质和蛋白质的合成。然而，关于这两种生物合成途径是否以及如何在分子水平上相互关联，人们知之甚少。众所周知，叶绿体丙酮酸脱氢酶复合物可产生用于脂肪酸的活化二碳前体分子（乙酰辅酶A），从而合成脂质。我们的前期工作表明，该酶的 DLA2 亚基也是核糖蛋白复合物的一个组成部分，并且在绿藻模型系统莱茵衣藻中叶绿体 mRNA 翻译的空间组织中具有功能。相反，RNA 结合影响丙酮酸脱氢酶活性。这些发现提供了关于质体内代谢信号和叶绿体基因表达如何相互关联以促进类囊体膜生物发生的第一个线索。此外，我们的数据提供了第一个线索，表明该蛋白质的这些双重作用可能存在于从蓝藻到人类的进化遥远的生物体中。在这个项目中，我们的目标是阐明这种涉及基因表达代谢控制的调控原理的精确分子工作模式。通过遵循莱茵衣藻的分子、遗传学和生物化学方法，我们将使用体内和体外技术来表征 DLA2 的 RNA 结合和酶促形式，DLA2 似乎在不同的蛋白质亚复合物之间穿梭。特别关注这些复合物的动力学和组成，以及乙酸酯/乙酰辅酶A在平衡 DLA2 两种功能中的作用。这项工作将得到蓝藻和高等植物的相关分析的补充，以测试这种调节开关的进化保守性。