Structure and Function of Protein Disorder in Membrane Trafficking and Organization

项目摘要/摘要 固有无序的蛋白质和蛋白质区域(IDPs和IDRs)缺乏稳定的三级结构，但保留了 生物功能。理解这种无序蛋白质区域的结构/功能关系 由于其高度可变和动态的性质，这是一个巨大的挑战。过去的几年里 结果提高了对境内流离失所者和境内流离失所者的流行率和作用的认识和认识 膜的贩运和组织。拟议研究的主要目标是推进我们的 了解IDPs的动态和高度可变的结构如何调节其膜功能 贩运和组织犯罪。IDP在膜贩运和组织方面的职能的一个关键方面包括 IdP-膜的直接相互作用，这种相互作用可以与无序到有序的转变一起发生，或者在 没有蛋白质的有序。膜结合两亲性螺旋(AHS)的形成是最常见的 前者的例子，但潜在的和调节的机制，稳定性，特异性和 这种膜相关AHS的功能仍然知之甚少。制约膜结合的因素 在束缚状态下保持无序的IDR就更不容易理解了。建议的一个主要领域 研究集中在用蛋白质描述这些类型的IDP-膜相互作用的机制上。 络合物作为体外结构和动力学表征与体内研究相结合的模型 功能分析。Idp功能的另一个新出现的方面是它们能够调节 凝结物或无膜细胞器。最近，有研究表明，含有IDR的膜- 结合蛋白可以形成胞浆凝聚体，隔离和组织细胞内的 膜泡。调节凝析油相互作用和组织能力的机制 膜性囊泡或隔室几乎没有被探索过，这是本研究的第二个主要焦点。 求婚。这些努力的主要模型系统将是由以下因素介导的膜小泡聚集 蛋白突触素，以及IDPs和IDR(如突触核蛋白和Rab)对这种聚集的调节 蛋白质。还将努力包括调查凝析油形成在小管组织中的作用。 囊泡细胞器，如内吞回收室(ERC)。这些系统将被描述为 利用结构/功能分析结合凝析油形成和囊泡的体外表征 通过原位和体内功能研究补充/释放。实现该提案的首要目标 将有助于增进我们对境内流离失所者和境内流离失所者在以下方面作用的不同机制的理解 对膜的贩运和组织的监管。通过关注具有生理功能的特定型号 意义，即控制囊泡胞吐和形成簇状囊泡结构的因素。 神经元和其他细胞类型的研究结果将对特定领域产生重大影响，并拓宽我们的 对蛋白质无序如何有助于细胞膜组织的一般理解。

Project Summary/Abstract Intrinsically disordered proteins and protein regions (IDPs and IDRs) lack stable tertiary structure but retain biological function. Understanding the structure/function relationships of such disordered protein regions presents a significant challenge because of their highly variable and dynamic nature. The past few years have resulted in an increased awareness and recognition of the prevalence and roles of IDPs and IDRs in membrane trafficking and organization. The primary goal of the proposed research is to advance our understanding of how the dynamic and highly variable structure of IDPs mediates their functions in membrane trafficking and organization. A key aspect of IDP function in membrane trafficking and organization involves direct IDP-membrane interactions, which can occur in conjunction with disorder-to-order transitions, or in the absence of protein ordering. Formation of membrane-binding amphipathic helices (AHs) is the most common example of the former, but the mechanisms underlying and regulating the formation, stability, specificity and function of such membrane-associated AHs remain poorly understood. Factors that govern membrane binding by IDRs that remain disordered in the bound state are even less well understood. A major area of proposed research centers on delineating mechanisms for these types of IDP-membrane interactions using the protein complexin as a model via a combination of in vitro characterization of structure and dynamics and in vivo functional assays. Another emerging aspect of IDP function is their ability to mediate the formation of condensates or membraneless organelles. Recently, it has been demonstrated that IDR-containing membrane- binding proteins can form cytosolic condensates that sequester and organize intracellular reservoirs of membrane vesicles. The mechanisms that regulate the ability of condensates to interact with and organize membranous vesicles or compartments have barely been explored and represent second major focus of this proposal. The primary model system for these efforts will be the clustering of membrane vesicles mediated by the protein synapsin, and the regulation of this clustering by IDPs and IDRs such as synucleins and rab proteins. Efforts will also include investigating the role of condensate formation in the organization of tubulo- vesicular organelles such as the endocytic recycling compartment (ERC). These systems will be characterized using structure/function analyses combining in vitro characterization of condensate formation and vesicle recruitment/release with in situ and in vivo functional studies. Achieving the overarching goals of this proposal will serve to advance our understanding of different mechanisms that underlie the roles of IDPs and IDRs in the regulation of membrane trafficking and organization. By focusing on specific models with physiological significance, namely factors governing vesicle exocytosis and the formation of clustered vesicular structures in neurons and other cell types, the results will make a significant impact on specific fields as well as broaden our general understanding of how protein disorder contributes to the organization of cellular membranes.