Fatty acid metabolism and intracellular lipid trafficking in plants

植物中的脂肪酸代谢和细胞内脂质运输

• 批准号: 279044026
• 负责人: Dr. Martin Fulda
• 金额: --
• 依托单位: Abteilung Biochemie der Pflanze
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2015
• 资助国家: 德国
• 起止时间: 2014-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/279044026?language=en
• 关键词: Fatty; acid; metabolism; intracellular; lipid

IntroductionIn plants, fatty acids serve multiple functions as structural components, as storage compounds, and as signaling substances. Given the multiple roles of fatty acids a complex regulatory network is obviously essential to match supply and demand of the diverse pathways of fatty acid metabolism. The regulation involves control over fatty acid biosynthesis, the activation, and the transport of fatty acids within the cell.ObjectivesIntracellular transport and enzymatic activation of fatty acids are cornerstones of the regulatory network of plant fatty acid metabolism and both will be addressed in the proposed project. The ER and the plastid are major sites of plant lipid metabolism and substrate trafficking between both subcellular domains was shown to be essential. In one part of the proposed project we will focus on identifying new components of the lipid transport machinery which is still poorly understood. In another part, the role of free fatty acids on transcriptional control will be analyzed.The metabolic availability of fatty acids in the cytoplasm is strongly dependent on their enzymatic activation by acyl-CoA synthetases (LACS). In the third part of the project we will employ LACS mutant lines with modified fatty acid availability to gain insight into the intricate network of plant fatty acid metabolism.MethodsWe identified recently an Arabidopsis mutant line characterized by impaired lipid trafficking between ER and plastids and by elevated levels of free fatty acids. We will analyze this mutant by whole transcriptome shotgun sequencing (RNA-seq) in order to identify new components of the lipid trafficking machinery. By the same experiment we will investigate the effects of elevated levels of free fatty acids on the transcriptome. As alternative approach to further characterize the lipid transport machinery we will use immunoaffinity purification of tagged versions of proteins involved in the transport in order to co-purify associated proteins.In Arabidopsis we observed functional redundancy between activities responsible for the activation of free fatty acids. To enable a reverse-genetic approach for the gene family we generated a mutant collection comprising more than 130 multiple mutant lines. Mutant lines with concise phenotypes will be analyzed by a set of biochemical, genetic, and cell biological methods in order to understand the biological roles of specific cellular fatty acid pools.OutlookThe data obtained will reveal insight into the flux of fatty acids within the cellular metabolism and will support future efforts aiming at the modification of plant lipid metabolism. Improving the understanding on lipid trafficking between different subcellular compartments will also allow us to test for similar mechanisms in other model organisms.

在植物中，脂肪酸作为结构成分、储存化合物和信号物质具有多种功能。鉴于脂肪酸的多重作用，一个复杂的调控网络显然是必不可少的，以匹配脂肪酸代谢的不同途径的供应和需求。调节涉及控制脂肪酸的生物合成，激活，和脂肪酸在cell.ObjectivesIntracellular运输和酶激活的脂肪酸是植物脂肪酸代谢的调控网络的基石，都将在拟议的项目解决。内质网和质体是植物脂类代谢的主要场所，两个亚细胞结构域之间的底物运输是必不可少的。在拟议项目的一部分，我们将集中精力确定新的组成部分的脂质运输机制，这仍然是知之甚少。另一部分将分析游离脂肪酸在转录调控中的作用，脂肪酸在细胞质中的代谢利用强烈依赖于它们被酰基辅酶A合成酶（拉克）激活。在该项目的第三部分，我们将采用拉克突变株系与修改的脂肪酸的可用性，以深入了解植物脂肪酸metabolis.MethodsWe最近确定了一个拟南芥突变株系，其特征在于受损的ER和质体之间的脂质运输和游离脂肪酸的水平升高。我们将通过全转录组鸟枪测序（RNA-seq）分析这种突变体，以确定脂质运输机制的新组分。通过相同的实验，我们将研究游离脂肪酸水平升高对转录组的影响。作为进一步表征脂质转运机制的替代方法，我们将使用免疫亲和纯化参与转运的标记蛋白，以共纯化相关蛋白。在拟南芥中，我们观察到负责激活游离脂肪酸的活动之间的功能冗余。为了使基因家族的反向遗传方法，我们产生了一个突变体集合，包括超过130多个突变株系。通过一系列生物化学、遗传学和细胞生物学方法对具有简明表型的突变株系进行分析，以了解特定细胞脂肪酸库的生物学作用。OutlookThe获得的数据将揭示细胞代谢中脂肪酸的通量，并将支持未来旨在修饰植物脂质代谢的努力。提高对不同亚细胞区室之间脂质运输的理解也将使我们能够在其他模式生物中测试类似的机制。