Properties and functions of plant CDP-diacylglycerol synthases

胞苷-二磷酸-二酰基甘油（CDP-DAG）合成酶催化磷脂酸活化为CDP-DAG，这是原核生物和真核生物合成甘油脂的中心中间体。它是植物细胞中磷脂酰肌醇、-丝氨酸、-甘油和心磷脂的直接前体，对各种细胞功能至关重要。对酵母和昆虫细胞的研究证明，CDP-DAG参与调节甘油脂生物合成和脂质依赖的信号转导过程。在植物中，CDP-DAG合成酶位于质体、线粒体和膜系统中，但除了它们的亚细胞定位外，对这些同工酶知之甚少。为了获得这一重要的蛋白质类别并研究其在植物中的功能，拟南芥编码cdp -二酰基甘油合成酶的基因将根据编码蛋白质的特性及其在植物细胞中的靶向性进行功能表征。在这些实验的基础上，还应开发和分析拟南芥突变体和转基因系，这些突变体和转基因系缺乏或过表达某些cdp -二酰基甘油合成酶，以研究它们的功能作用。

Cytidine-diphosphate-diacylglycerol (CDP-DAG) synthases catalyse the activation of phosphatidic acid to CDP-DAG, a central intermediate in glycerolipid biosynthesis of both prokaryotic and eukaryotic organisms. It is the direct precursor to phosphatidylinositol, -serine, -glycerol and cardiolipin in plant cells which are essential for various cellular functions. Studies with yeast and insect cells provided evidence that CDP-DAG is involved in regulating glycerolipid biosynthesis and lipid dependent signal transduction processes. In plants, CDP-DAG synthases are located in plastids, mitochondria and the endomembrane system, but apart from their subcellular localisation very little is known about these isozymes. To gain access to this important protein class and to study their functions in plants, the genes of Arabidopsis thaliana encoding CDP-diacylglycerol synthases are to be functionally characterised with regard to the properties of the encoded proteins and their targeting within plant cells. These experiments shall be complemented by the development and analysis of A. thaliana mutants and transgenic lines, deficient in certain CDP-diacylglycerol synthases or over-expressing the respective ones in order to investigate their functional roles.