Identifying Targets/Pathways of Chemical Probes for the Plant Endomembrane System

确定植物内膜系统化学探针的靶点/途径

• 批准号: 0817916
• 负责人: Natasha Raikhel
• 金额: --
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2011-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0817916&HistoricalAwards=false
• 关键词: Identifying; Targets; Pathways; Chemical; Probes

The vacuole is prominent in plant cells and is required for viability. This compartment is responsible for storing sugars, pigments, ions, proteins, and volatile compounds necessary for the flavor and nutrition of fruits and vegetables, and it maintains cellular homeostasis by regulating cytosolic pH. Plant vacuoles breakdown and recycle cellular components, and are involved in detoxification, as do yeast and mammalian lysosomes. However, plant vacuoles perform additional functions in defense. The vacuole is part of the endomembrane system, which includes the endoplasmic reticulum, the Golgi apparatus, the trans-Golgi network, pre-vacuolar compartments, endosomes and the plasma membrane. Transport between these compartments occurs via vesicle trafficking. Beyond a role in cargo delivery, the plant endomembrane system is essential for development and signal transduction. A large proportion of knockout mutations in the Arabidopsis endomembrane system are either lethal or provide no visible phenotype due to complete or partial redundancy. However, the use of diverse chemicals to interrogate molecular processes provides a novel avenue for rapid and effective dissection of mechanisms and gene networks in ways not feasible with mutation-based approaches. Three novel compounds have been identified that specifically disrupt the trafficking of membrane or soluble proteins to the vacuole. Sortin1 affects the morphology of the vacuole and the delivery of the vacuolar lumen proteins CPY and invertase. However, it does not affect the delivery of tonoplast or other membrane proteins or the morphology of Golgi, ER or endosomes. In contrast, Gravacin interferes with protein trafficking to the tonoplast (and the trafficking of at least one plasma membrane protein) but does not affect the delivery of lumen proteins. Another chemical, known as 050, affects the localization of proteins that traffic through the ER and induces the fusion of multiple compartments. This combination of pharmacological reagents is a powerful resource to discover new components of the trafficking machinery within these pathways. The challenge now is to: identify target(s) or/and pathway(s) of each compound by genetic approaches. The intellectual merit of this award is that novel components of the protein trafficking machinery will be identified using our reagents. Furthermore, this diverse set of chemical probes will permit scientists to understand the relationships between protein trafficking pathways to the vacuole and other pathways within the cell, a challenge for classical mutational approaches. More broadly, the chemical genomics approach can be easily translated to any eukaryotic system, as well as plants of economic importance and human disease and nutrition. A truly interdisciplinary approach to understand the mechanisms of endomembrane trafficking has produced a new cohort of scientists. During the last several years, students and postdocs in the Raikhel laboratory have become well-versed and experienced in cell and molecular biology, genetics, chemistry and computational sciences, all necessary to ensure the success of the proposal and to become competitive in the workforce. The broad impact of this award will continue by producing, in addition to scientific discoveries, a new generation of diverse scientists who can form complementary teams required for 21st century research and education.

液泡在植物细胞中很突出，是生存所必需的。该隔室负责储存水果和蔬菜的风味和营养所必需的糖、色素、离子、蛋白质和挥发性化合物，并且它通过调节胞质pH来维持细胞内稳态。植物液泡分解并回收细胞组分，并且参与解毒，就像酵母和哺乳动物溶酶体一样。然而，植物液泡在防御中执行额外的功能。液泡是内膜系统的一部分，内膜系统包括内质网、高尔基体、高尔基体网络、前液泡区室、内体和质膜。这些区室之间的运输通过囊泡运输发生。除了在货物运输的作用，植物内膜系统是必不可少的发展和信号转导。在拟南芥内膜系统中，大部分敲除突变要么是致死的，要么由于完全或部分冗余而不提供可见的表型。然而，使用不同的化学物质来询问分子过程提供了一个新的途径，快速和有效的解剖机制和基因网络的方式不可行的突变为基础的方法。已经鉴定了三种新的化合物，它们特异性地破坏膜或可溶性蛋白质向液泡的运输。Sortin 1影响液泡的形态和液泡腔蛋白CPY和转化酶的递送。然而，它不影响液泡膜或其他膜蛋白的递送或高尔基体、ER或内体的形态。相比之下，Gravacin干扰蛋白质运输到液泡膜（以及至少一种质膜蛋白的运输），但不影响腔蛋白的递送。另一种化学物质，称为050，影响通过ER运输的蛋白质的定位，并诱导多个隔室的融合。 这种药理试剂的组合是发现这些途径中贩运机制新组成部分的有力资源。 现在的挑战是：通过遗传方法确定每种化合物的靶点或/和途径。这个奖项的智力价值是，蛋白质运输机制的新组件将被确定使用我们的试剂。此外，这种多样化的化学探针将使科学家能够了解蛋白质运输途径与细胞内其他途径之间的关系，这对经典的突变方法是一个挑战。更广泛地说，化学基因组学方法可以很容易地转化为任何真核系统，以及具有经济重要性的植物和人类疾病和营养。一个真正的跨学科的方法来了解内膜运输的机制产生了一个新的科学家群体。在过去的几年里，Raikhel实验室的学生和博士后已经精通细胞和分子生物学，遗传学，化学和计算科学，所有这些都是确保提案成功并在劳动力中具有竞争力所必需的。该奖项的广泛影响将继续产生，除了科学发现，新一代的多样化的科学家谁可以形成互补的团队所需的21世纪的研究和教育。