Innate immunity-associated recycling endosome in Arabidopsis and pathogen attack

 本研究的长期目标是阐明天然免疫系统的囊泡运输网络，以及病原体如何调节这一网络以引起传染病。植物和哺乳动物共享功能相似的先天免疫系统，这对对抗微生物病原体非常重要。尽管在过去的二十年里，我们对植物和哺乳动物的先天免疫系统的了解取得了许多令人振奋的进展，但在这两个系统中仍然存在着重大的知识差距。先天性免疫系统一个特别鲜为人知的方面是囊泡运输成分，它控制着免疫相关的受体、信号成分和货物。在过去的二十年里，易驯化的拟南芥-丁香假单胞菌病理系统已被用来发现和表征许多天然免疫调节因子，以及调节天然免疫反应的病原体效应物。通过对细菌效应物HopM1的研究，首席研究员的实验室发现了MIN7蛋白，这是一种拟南芥鸟苷核苷酸交换因子，属于ADP核糖化因子(ARF)家族。MIN7位于回收质膜蛋白的早期内体中，是植物天然免疫的所有主要分支所必需的，这表明它在天然免疫运输中起着关键作用。MIN7相关内小体的鉴定现在提供了一个令人兴奋的切入点，以获得全面了解在模型真核系统中免疫交通中特征不佳的循环内小体。本研究将从分子遗传学、细胞生物学、生物化学和微生物发病机制等多个角度对MIN7相关的囊泡运输进行综合研究。该项目的具体目标是：1)研究MIN7蛋白在疾病和免疫过程中的稳定性，2)鉴定和表征免疫相关的MIN7蛋白复合体和MIN7相关的循环内小体的组成，以及3)表征新发现的MIN7相关的局灶性免疫区(MAIZ)。阐明MIN7调节先天免疫流量的机制有可能阐明先天免疫反应的基本原理。加强对宿主先天免疫系统及其被微生物病原体操纵的了解，有望为开发人类和植物疾病干预的新方法提供基础知识。

 DESCRIPTION (provided by applicant): Innate immunity-associated endosomes and pathogen attack in Arabidopsis PI: HE, Sheng Yang; Michigan State University Project summary The long-term goal of this research is to elucidate the vesicle trafficking network of the innate immune system and how pathogens modulate this network to cause infectious diseases. Plants and mammals share functionally analogous innate immune systems that are important for combating microbial pathogens. Despite many exciting advances over the past two decades in our understanding of plant and mammalian innate immune systems, major knowledge gaps remain in both systems. A particularly poorly understood aspect of the innate immune system is the vesicle trafficking component that controls immunity-associated receptors, signaling components, and cargoes. For the past two decades, the tractable Arabidopsis-Pseudomonas syringae pathosystem has been used to discover and characterize many innate immune regulators, as well as pathogen effectors that modulate innate immune responses. By studying the bacterial effector HopM1, the principal investigator's laboratory discovered the MIN7 protein, an Arabidopsis guanine nucleotide exchange factor (GEF) belonging to the ADP ribosylation factor (ARF) family. MIN7 is located in early endosomes that recycle plasma membrane proteins and is required for all major branches of plant innate immunity, suggesting a key role in innate immune traffic. The identification of MIN7-associated endosomes now provides an exciting entry point for gaining a comprehensive understanding of the poorly characterized recycling endosomes in immune traffic in a model eukaryotic system. In this research, an integrative approach, involving methods in molecular genetics, cell biology, biochemistry, and microbial pathogenesis, will be taken to understand MIN7-associated vesicle traffic. The specific goals of this project are: 1) to investigate MIN7 protein stability during disease and immunity, 2) to identify and characterize the components of the immune-associated MIN7 protein complex and MIN7-associated recycling endosomes, and 3) to characterize the newly discovered MIN7-associated focal immune zones (MAIZs). Elucidating the mechanisms by which MIN7 regulates innate immune traffic has the potential to illuminate the fundamental principles underlying innate immune responses. Enhanced understanding of host innate immune systems and their manipulation by microbial pathogens promises to provide fundamental knowledge for the development of novel methods of disease intervention in humans and plants.