Wrestling with pathogens: host SUMOylation and bacterial interference in the plant immune system

信号处理中的一个基本“工程”问题包括将触发阈值和动态范围整合到灵敏度和特异性之间的有益平衡中。一个很好的例子是免疫系统，生物体需要仔细控制免疫系统，以便在面对威胁性病原体时能够迅速激活，但要保持控制以防止破坏性副作用。在植物中，当细胞内免疫受体检测到入侵病原体蛋白质的存在时，最强的免疫反应之一被触发，该入侵病原体蛋白质由病原体部署以操纵宿主细胞，这一过程称为效应触发免疫。该项目旨在揭示生物体校准调节免疫反应特异性和强度的复杂信号模块的原理。在实践层面上，植物免疫应答的详细知识可能导致作物植物在长期内具有改善的先天病原体抗性的持久性，对可持续农业和生物质生产以及环境具有显著益处。该项目的更广泛影响还包括培训本科生和研究生以及博士后研究员。此外，该项目还将支持学生参加一个名为“植物科学新生研究”（FRIPS）的全校范围的项目，并将通过课堂参观和在夏季为密苏里大学教师组织研究模块，进一步发展与密苏里州塞达利亚的初中和高中教师的联系，重点是植物拟南芥中的一种免疫调节剂，名为SRFR 1。目前对SRFR 1蛋白功能的理解表明，SRFR 1是一种免疫适配蛋白，在时间和空间上调节蛋白复合物的存在和稳定性，以微调免疫输出。在本项目中，将研究调节SRFR 1蛋白质-蛋白质相互作用的机制。具体而言，SRFR 1结合SUMO（一种附着于其他蛋白质以调节其在细胞中的位置的小蛋白质）的迹象表明，SRFR 1通过SUMO化调节与其他蛋白质的相互作用的机制。这将使用遗传学，细胞生物学和蛋白质组学的组合进行测试，以确定SRFR 1客户蛋白的SUMO化是否以及何时发生，以及这是否决定了蛋白质复合物的细胞位置。此外，该项目还将调查病原体是否会干扰这一过程。

A fundamental "engineering" problem in signal processing consists of integrating trigger threshold and dynamic range into a beneficial balance between sensitivity and specificity. A good example is the immune system, which organisms need to carefully control so that it can be rapidly activated when faced with a threatening pathogen, but kept in check to prevent damaging side effects. In plants, one of the strongest immune responses is triggered when intracellular immune receptors detect the presence of intruding pathogen proteins deployed by the pathogen to manipulate the host cell, a process called effector-triggered immunity. This project aims to uncover principles by which living organisms calibrate the complex signaling modules that regulate the specificity and intensity of immune responses. On a practical level, detailed knowledge of the plant immune response may lead to crop plants with improved durability of innate pathogen resistance in the long term, with significant benefits to sustainable agricultural and biomass production and the environment. This project's broader impacts also include the training of undergraduate and graduate students and of a post-doctoral researcher. In addition, the project will support students in a campus-wide program called Freshman Research in Plant Sciences (FRIPS), and will further develop connections to middle and high school teachers in Sedalia, MO, through classroom visits and the organization of research modules at MU for teachers in the summer.The focus is on an immune regulator in the plant Arabidopsis thaliana called SRFR1. Current understanding of SRFR1 protein function suggests that SRFR1 is an immune adaptor protein that temporally and spatially regulates the presence and stability of protein complexes to fine-tune immune outputs. In this project, the mechanisms that regulate SRFR1 protein-protein interactions will be investigated. Specifically, the indication that SRFR1 binds SUMO, a small protein that is attached to other proteins to regulate their location in the cell, suggests a mechanism for regulating SRFR1 interactions with other proteins by SUMOylation. This will be tested using a combination of genetics, cell biology and proteomics to establish whether and when SUMOylation of SRFR1 client proteins occurs, and whether this determines the cellular location of protein complexes. In addition, the project will investigate if pathogens interfere with this process.