Structural Basis for Rab and Arf GTPase Regulated Membrane Trafficking

 描述(由申请人提供)：RAB、Arf和ARL GTP酶是控制膜运输以及膜分隔细胞器的生物发生、鉴定和成熟的系统的核心调节组件。这些基本控制机制的缺陷与复杂的疾病状态和基因相关疾病有关。转运GTP酶的功能循环和输出，包括鸟核苷酸交换因子(GEF)的激活、GTP酶激活蛋白(GAP)的失活和与效应物的相互作用，也受到病毒、细菌和真核病原体的操纵，以逃避宿主反应和支持复制。了解GTP酶调控贩运的基本机制，以及这些机制如何被病原体操纵并在疾病条件下失控，是一项至关重要的挑战。GEF和GAP的膜募集和自动调节是控制贩运GTP酶功能产出的主要范例。这一应用的中心目标是通过结合多种生化、生物物理和结构方法，从宿主和病原体的角度研究分子和结构机制，以识别潜在的全球环境基金和GAP催化活性的时空控制的新原理。特别是，我们将研究以下结构机制：ARF全球环境基金膜招募和变构激活(目标1)；嗜肺军团菌的膜靶向以及与质膜合成素的相互作用(目标2)；以及GAP和病原体操纵使Rab失活。这些研究将为宿主生物体中的运输控制机制以及这些过程如何被细胞内病原体颠覆提供新的见解。这一结果可能有助于设计针对GTPase依赖的贩运过程的基于机制的治疗策略。

 DESCRIPTION (provided by applicant): Rab, Arf and Arl GTPases function as core regulatory components of systems that control membrane trafficking as well as the biogenesis, identity, and maturation of membrane delimited organelles. Defects in these fundamental control mechanisms are implicated in complex disease states and genetically-linked disorders. The functional cycle and outputs of trafficking GTPases, including activation by guanine nucleotide exchange factors (GEFs), deactivation by GTPase activating proteins (GAPs), and interactions with effectors, are also manipulated by viral, bacterial, and eukaryotic pathogens to evade host responses and support replication. Understanding the mechanisms underlying trafficking regulation by GTPases and how these mechanisms are manipulated by pathogens and dysregulated in disease conditions represents a critically important challenge. Membrane recruitment and autoregulation of GEFs and GAPs are major paradigms for controlling the functional outputs of trafficking GTPases. The central objective of this application is to discern new principles underlying spatiotemporal control of GEF and GAP catalytic activities by combining multiple biochemical, biophysical, and structural approaches to investigate the molecular and structural mechanisms from host and pathogen perspectives. Specially, we will investigate structural mechanisms for: Arf GEF membrane recruitment and allosteric activation (Aim 1); membrane targeting of the Legionella pneumophila GEF DrrA and interaction with plasma membrane syntaxins (Aim 2); and Rab deactivation by GAPs and manipulation by pathogens. These studies will provide new insights into trafficking control mechanisms in host organisms and how these processes are subverted by intracellular pathogens. The results may be useful for the design of mechanism- based therapeutic strategies targeting GTPase dependent trafficking processes.