Analysis of APP1 Regulation of Auxin and Jasmonic Acid Signalling in Arabidopsis

拟南芥中 APP1 对生长素和茉莉酸信号传导的调节分析

• 批准号: 0820648
• 负责人: Angus Murphy
• 金额: $ 25.01万
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0820648&HistoricalAwards=false
• 关键词: Analysis; APP1; Regulation; Auxin; Jasmonic

Project Abstract In plants, the TIR1/AFB receptor proteins regulate responses to the plant hormone auxin by stimulating the proteolytic degradation of AUX/IAA repressors of auxin-dependent gene transcription. Almost all auxin responses have been shown to involve specific pairings of TIR1/AFBs, AUX/IAAs, and auxin-responsive transcriptional activators. Experiments with the prolyl cis-trans isomerase (PPIase) inhibitor juglone suggest that a PPIase may control the rate of AUX/IAA degradation in an auxin-independent manner. Recently, the investigators have discovered that Arabidopsis APP1, which possesses juglone-sensitive X-prolyl aminopeptidase and PPIase activities, directly interacts with AUX/IAA proteins via their interaction domains. As compared to wild type plants, these app1 mutants exhibit reduced auxin sensitivity; they have reduced elongation growth, as well as sharply decreased expression of auxin responsive genes and synthetic reporters after auxin treatment. Increased APP1 activity results in increased auxin-responsive gene expression and growth similar to that seen in plants treated with low concentrations of auxin. The overall goal of the project is to elucidate the role of APP1 in TIR1/AFB-mediated auxin signaling. The specific objectives of the project are as follows. 1) The project will determine which enzymatic activity of APP1 regulates auxin responses. The investigators hypothesize that the PPIase activity mediatesTIR1-AUX/IAA interactions and that the proteolytic activity contributes to subsequent AUX/IAA processing. 2) The project will determine the function of APP1 in the auxin response pathway. The model underlying the work proposes that APP1 stabilizes the interaction domain of AUX/IAAs to promote TIR1 binding. This project is expected to characterize an unrecognized global component of plant hormone signaling. The project is transformative, as it will help determine whether the PPIase activity discovered in AtAPP1 is found in APP orthologs from other species and whether APPs may play a previously uncontemplated role in animal and fungal signaling mechanisms. The project will also involve students from a summer undergraduate research program run by the PI and Dr. Wendy Peer that recruits students into the life sciences from underserved populations.

在植物中，TIR 1/AFB受体蛋白通过刺激生长素依赖基因转录的AUX/IAA阻遏物的蛋白水解降解来调节对植物激素生长素的反应。几乎所有的生长素反应都涉及到TIR 1/AFB、AUX/IAAs和生长素反应性转录激活因子的特异性配对。用脯氨酰顺反异构酶（PPIase）抑制剂胡桃醌的实验表明，PPIase可以以不依赖生长素的方式控制AUX/IAA的降解速率。近年来，研究者发现拟南芥APP 1具有胡桃醌敏感的X-prolyl氨基肽酶和PPIase活性，可通过AUX/IAA蛋白的相互作用结构域直接与AUX/IAA蛋白相互作用。与野生型植物相比，这些app 1突变体表现出降低的生长素敏感性;它们具有降低的伸长生长，以及在生长素处理后生长素响应基因和合成报告基因的表达急剧降低。增加的APP 1活性导致生长素响应基因表达和生长的增加，类似于用低浓度生长素处理的植物中所见。该项目的总体目标是阐明APP 1在TIR 1/AFB介导的生长素信号转导中的作用。该项目的具体目标如下。1)该项目将确定APP 1的哪种酶活性调节生长素反应。研究人员假设PPIase活性介导TIR 1-AUX/IAA相互作用，并且蛋白水解活性有助于随后的AUX/IAA加工。2)该项目将确定APP 1在生长素反应途径中的功能。这项工作的基础模型提出，APP 1稳定了AUX/IAAs的相互作用结构域，以促进TIR 1结合。该项目预计将表征植物激素信号传导的未被识别的全球组成部分。该项目是变革性的，因为它将有助于确定在AtAPP 1中发现的PPIase活性是否存在于其他物种的APP直系同源物中，以及APP是否可能在动物和真菌信号传导机制中发挥先前未考虑的作用。该项目还将涉及PI和Wendy Peer博士开展的暑期本科研究项目的学生，该项目从服务不足的人群中招募学生进入生命科学。