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Elucidating structure-function relationship and signaling mechanisms of the novel group III G gamma protein AGG3 in Arabidopsis

阐明拟南芥中新型 III 族 G γ 蛋白 AGG3 的结构功能关系和信号机制

基本信息

批准号：
1557942
负责人：
Sona Pandey
金额：
$ 59.71万
依托单位：
Donald Danforth Plant Science Center
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2016
资助国家：
美国
起止时间：
2016-07-01 至 2021-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1557942&HistoricalAwards=false
关键词：
Elucidating structure function relationship signaling

项目摘要

Due to their sessile nature, plants continuously adjust their growth, development and productivity in accordance with their surroundings. They respond to environmental stresses (e.g. drought, cold temperatures), various pathogens, low or high nutrient availability, and interactions with other organisms by precise modification of underlying signaling pathways. Several proteins, many of which are present in all organisms, have evolved plant-specific structural features and functions to effectively address these challenges. One such group of proteins is the heterotrimeric G-protein family, which although present in all eukaryotes, has certain plant-specific components and features. This research seeks to discover the unique signaling pathways regulated by a novel, plant-specific G&gamma; protein, AGG3, of Arabidopsis. Results obtained from this research will help us understand how plants maintain their yield against environmental stresses. These results will have potential practical applications in the breeding or engineering of more productive crops with limited resources. The work will also involve the training of a postdoctoral researcher in a multidisciplinary field and mentoring of undergraduate students. The research will help promote an understanding of plant science to the high school students and general public thorough a series of hands on experiments and interactive presentations.Even though all eukaryotes possess heterotrimeric G-proteins and their overall signaling mechanisms are broadly conserved, plants have taken the 'core' G-protein system and rewired it to meet their needs. One novel component of the plant G-protein system is the newly discovered, higher plant-specific, type III (or Class C) G&gamma; protein, represented by AGG3 in Arabidopsis. Type III G&gamma; proteins have a modular architecture, with an N-terminal domain similar to canonical G&gamma; , fused with a large C-terminal extension (up to 3 times the length of G&gamma; domain) that contains up to 35% cysteine (Cys). The type III G&gamma; proteins are currently a focus of intense research due to their involvement in regulation of many agronomically important processes in plants, including seed yield, organ size regulation, abscisic acid (ABA)-dependent signaling and stress responses, and nitrogen use efficiency. The mode of action of these proteins remains largely unknown, and some unique mechanisms that are independent of the classic G-protein cycle are also proposed. This research therefore aims to determine the G-protein-dependent and -independent roles of AGG3, and elucidate its underlying signaling mechanisms; especially those operative during abiotic stress signaling. Genetic complementation of single and higher order mutants will be performed using specific domains of AGG3, followed by identification of its protein interaction network. These analyses will help define the role of AGG3 and its network elements in abiotic stress signaling pathways and how it is related to its ability to control yield.

由于它们的固着性，植物根据周围环境不断调整它们的生长，发育和生产力。它们对环境压力（如干旱，低温），各种病原体，低或高营养供应，以及通过精确修改潜在的信号通路与其他生物体的相互作用作出反应。几种蛋白质，其中许多存在于所有生物体中，已经进化出植物特有的结构特征和功能，以有效地应对这些挑战。其中一组蛋白质是异源三聚体G蛋白家族，虽然存在于所有真核生物中，但具有某些植物特异性组分和特征。本研究旨在发现一种新的，植物特异性的G γ蛋白，AGG 3，拟南芥的独特的信号转导途径。从这项研究中获得的结果将有助于我们了解植物如何在环境胁迫下保持产量。这些结果将有潜在的实际应用在育种或工程更生产力的作物有限的资源。这项工作还将涉及在多学科领域培训一名博士后研究员和指导本科生。这项研究将通过一系列的动手实验和互动演示，促进高中生和公众对植物科学的理解。尽管所有的真核生物都拥有异源三聚体G蛋白，而且它们的整体信号传导机制广泛保守，但植物已经采取了“核心”G蛋白系统，并将其重新连接以满足它们的需求。植物G蛋白系统的一种新组分是新发现的高等植物特异性III型（或C类）G γ蛋白，在拟南芥中以AGG 3为代表。III型G γ蛋白具有模块化结构，具有与典型G γ类似的N-末端结构域，与含有高达35%半胱氨酸（Cys）的大C-末端延伸（高达G γ结构域长度的3倍）融合。III型G& γ;由于蛋白质参与调节植物中许多农艺学上重要的过程，包括种子产量、器官大小调节、脱落酸（阿坝）依赖性信号传导和胁迫反应以及氮利用效率，因此蛋白质是当前深入研究的焦点。这些蛋白质的作用模式在很大程度上仍然未知，并且还提出了一些独立于经典G蛋白循环的独特机制。因此，本研究旨在确定AGG 3的G蛋白依赖性和非依赖性作用，并阐明其潜在的信号转导机制，特别是那些在非生物胁迫信号转导过程中起作用的机制。将使用AGG 3的特定结构域进行单个和高阶突变体的遗传互补，然后鉴定其蛋白质相互作用网络。这些分析将有助于确定AGG 3及其网络元件在非生物胁迫信号传导途径中的作用，以及它如何与其控制产量的能力相关。