Protein Ubiquitination and Plant Response to Environmental Stress

蛋白质泛素化和植物对环境胁迫的反应

• 批准号: RGPIN-2018-05612
• 负责人: Stone, Sophia
• 金额: $ 3.42万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=666041
• 关键词: Protein; Ubiquitination; Plant; Response; Environmental

Ubiquitination is a prevalent post-translation modification system that is involved in almost every aspects of eukaryotic biology. It involves the attachment of ubiquitin, a small, highly conserved protein to selected substrates. The outcome of ubiquitination varies depending on the nature of the modification and can include degradation, relocalization and activation of the substrate. The versatility of the ubiquitin molecule is due to the fact that it can be attached as a single molecule (monoubiquitination) or it can be used to build chains (polyubiquitination) of varying topology on an internal lysine residue of the substrate. The most notable function of ubiquitin is the targeting of substrate proteins to the multi-proteolytic 26S proteasome complex for degradation. The ubiquitin proteasome system (UPS) controls the abundance of numerous enzymes, structural and regulatory proteins ensuring proper cellular function. Plants, as sessile organisms, utilize the UPS to facilitate cellular changes required to respond to and tolerate adverse growth conditions. Environmental stresses such as water scarcity, increase temperature, nutrient derivation and pathogen infection can limit crop productivity by negatively impacting growth and development. Recent advances have broadened our understanding of UPS function, however major knowledge gaps remain including the identity of substrates and a clear understanding of how the system regulate protein abundance to facilitate stress responses. The goal of this research program is to gain an in-depth understanding of the regulatory role of the UPS in plant biology, particularly response to environmental stresses. We will identify proteins that are regulated by the UPS to facilitate responses required for defending against pathogen attack, increasing root iron uptake when availability is reduced, and enhancing tolerance of high temperature conditions. We will define the molecular mechanisms that regulate E3-substrate engagement to ensure that the appropriate response occurs to ameliorate damage during exposure to external stressors. We will also investigate the role of the UPS in regulating calcium-mediated stress signalling by studying the ubiquitin-dependent degradation of calcium activated protein kinases. This research will give insight into how the UPS can possibly be manipulated to provide an advantage to plants growing under unfavourable environmental conditions. Information obtained will aid in understanding UPS function in higher plants and better our understanding of similar processes in crops that are of commercial significance to the Canadian economy.

泛素化是一种普遍存在的翻译后修饰系统，几乎涉及到真核生物的各个方面。它涉及到泛素的附着，泛素是一种小的、高度保守的蛋白质，被选择的底物。泛素化的结果根据修饰的性质而不同，可能包括底物的降解、重新定位和激活。泛素分子的多功能性是因为它可以作为单个分子连接(单泛素化)，或者它可以用来在底物的内部赖氨酸残基上构建不同拓扑结构的链(多泛素化)。泛素最显著的功能是将底物蛋白靶向于多蛋白水解性的26S蛋白酶体复合体进行降解。泛素蛋白酶体系统(UPS)控制着大量的酶、结构蛋白和调节蛋白的丰富，确保了细胞的正常功能。植物作为固着生物，利用UPS促进细胞变化，以响应和耐受不利的生长条件。环境胁迫，如缺水、温度升高、营养衍生和病原菌侵染等，会对作物的生长发育产生负面影响，从而限制作物的产量。最近的进展拓宽了我们对UPS功能的理解，但主要的知识空白仍然存在，包括底物的识别和对该系统如何调节蛋白质丰度以促进应激反应的清楚理解。这项研究计划的目标是深入了解UPS在植物生物学中的调节作用，特别是对环境胁迫的反应。我们将确定受UPS调控的蛋白质，以促进抵御病原体攻击所需的反应，在可利用性降低时增加根部铁摄取，以及增强对高温条件的耐受性。我们将确定调节E3底物结合的分子机制，以确保在暴露于外部应激源时发生适当的反应以减轻损伤。我们还将通过研究钙激活蛋白激酶泛素依赖的降解来研究UPS在调节钙介导的应激信号中的作用。这项研究将深入了解UPS如何可能被操纵，为在不利环境条件下生长的植物提供优势。所获得的信息将有助于了解UPS在高等植物中的功能，并有助于我们更好地了解对加拿大经济具有商业意义的作物中的类似过程。