Collaborative Research: Function and Regulation of Thimet Oligopeptidase-Mediated Proteolytic Pathways in Plant Stress

植物是动态的生命系统，其中外部和内部信号整合以促进和维持生长和健康。本研究旨在了解植物如何利用蛋白质裂解和降解来响应胁迫信号的尚未被研究的现象。这些知识可能会提高作物的存活率，并进一步了解这些作物所利用的适应和耐受机制。研究生、本科生和高中生将接受生物化学、分析化学、系统和计算生物学等现代方法的培训。本科生将有机会参加密西西比州立大学和北卡罗来纳大学教堂山分校之间的本科生暑期交流研究经验（REU）项目，pi将为北卡罗来纳科学节开发一个针对中小学生的科学演示展览。该项目以拟南芥为模型，通过综合生化、蛋白质组学和系统生物学方法，阐明TOP1和TOP2硫寡肽酶介导的蛋白水解途径的贡献。在初步研究中采用了独特的方法来表征硫柳寡肽酶与植物胁迫激素水杨酸的相互作用。遗传和生化实验揭示了TOPs作为“氧化还原传感器”在病原体防御中的作用。TOP1和TOP2细胞功能之间的基本差异已经通过实验揭示并在细胞水平的计算模型中被捕获。该研究将在这些发现的基础上进行扩展，解决以下几个方面：(i)表征由TOP1和TOP2介导和调节的氧化还原特异性修饰，（ii）确定TOP1和TOP2的底物库，以及（iii）扩展和验证连接TOP1和TOP2分子和结构特征与全细胞反应的预测模型。一旦这项研究的成功完成，将建立一个植物TOP信号的框架，并为如何利用蛋白质水解途径和防御激素信号之间的相互作用来促进作物的适应和耐受机制提供重要的见解。该项目由分子和细胞生物科学部的系统和合成生物学项目以及NSF EPSCoR项目共同资助。

Plants are dynamic living systems in which external and internal signals are integrated to facilitate and sustain growth and health. This research is targeted toward understanding the understudied phenomena of how plants use protein cleavage and degradation in response to stress signals. This knowledge may lead to increased survival rates of crops, and a further understanding of the adaptation and tolerance mechanisms utilized by these crops. A diverse population of graduate, undergraduate and high school students will be trained in modern methods of biochemistry, analytical chemistry, and systems and computational biology. Undergraduates will have the opportunity to participate in a summer exchange Research Experience for Undergraduates (REU) program between Mississippi State University and University of North Carolina at Chapel Hill and the PIs will develop an exhibit with scientific demonstrations for the NC Science Festival targeted to elementary and middle school students. The project employs the plant Arabidopsis as a model to elucidate the contributions of the proteolytic pathways mediated by TOP1 and TOP2 thimet oligopeptidases through integrated biochemical, proteomics, and systems biology approaches. Unique methods have been utilized in the preliminary studies to characterize the interaction of thimet oligopeptidases with the plant stress hormone salicylic acid. Genetic and biochemical experiments uncovered roles for TOPs in pathogen defense as possible "redox sensors". Fundamental differences between TOP1 and TOP2 cellular functions have been revealed experimentally and captured in a cell-level computational model. The research will expand on these findings by addressing the following aspects: (i) characterize redox-specific modifications mediated by and regulating TOP1 and TOP2, (ii) identify the substrate repertoire of TOP1 and TOP2, and (iii) expand and verify predictive models bridging molecular and structural characteristics of TOP1 and TOP2 with the whole-cell response. Upon the successful completion of the proposed research, a framework for TOP signaling in plants will be established and provide critical insights into how the interplay between proteolytic pathways and defense hormone signaling can be harnessed for the benefit of adaptation and tolerance mechanisms of crops.This project is co-funded by the Systems and Synthetic Biology Program in the Division of Molecular and Cellular Biosciences and by the NSF EPSCoR Program.