Interaction of Amyloidogenic Proteins with Asymmetric Membranes

许多重要的生物过程都涉及到蛋白质与细胞膜的相互作用。据认为，这种相互作用在某些抗菌蛋白杀死细菌中起作用。它们也可能在淀粉样蛋白疾病（如阿尔茨海默病）期间人类细胞的死亡中发挥重要作用。膜蛋白相互作用的重要性超越了生物学，通过与膜的相互作用来制作特定结构的模板在生物启发材料中有应用。蛋白质与膜相互作用的高分辨率分子水平研究可能导致更好的抗菌药物的设计和新材料的开发。不幸的是，研究人员被迫使用相对粗糙的生物膜模拟，不能捕捉到天然细胞膜的关键方面。特别是，天然细胞膜是不对称的，即膜的内层与外层的组成不同。这种影响对他们的行为有重要的影响。该项目将利用最近的技术突破来研究一类重要的人类蛋白质的代表成员与现实的不对称模型膜的相互作用。这项研究将为蛋白质如何与生物膜相互作用并诱导细胞死亡提供前所未有的高分辨率视图。该项目包括致力于培养下一代STEM学生的重大努力，包括旨在增加本科生参与研究和促进女性参与STEM学科的举措。该项目将定义利用生物相关的不对称膜催化内在无序多肽（IDPs）聚集的原理，重点是淀粉样蛋白多肽IAPP。多肽在膜上的聚集是淀粉样纤维形成的一个普遍特征，可能在某些抗微生物多肽的功能中起作用。不幸的是，现有的模型膜对相关的质膜的模拟非常差。这阻碍了膜诱导自组装和膜活性的生物物理研究，使得将高分辨率生物物理研究与体内情况联系起来非常具有挑战性。该项目将使用具有生理相关脂质组成和胆固醇的不对称膜，以及高分辨率探测蛋白质聚集的新方法。之所以选择IAPP作为模型系统，是因为它广泛代表了IDPs的淀粉样蛋白形成，并且因为该系统具有丰富的生化、生物物理和生物学数据。从研究中产生的原理将适用于广泛的系统，包括其他淀粉样蛋白和抗微生物肽。该项目得到了生物科学理事会分子和细胞生物科学部分子生物物理集群的支持。

Many important biological processes involved the interaction of proteins with cell membranes. It is thought that such interactions have a role in the killing of bacteria by certain anti-bacterial proteins. They may also play an important role in the death of human cells during amyloid diseases such as Alzheimer's disease. The importance of membrane protein interactions extends beyond biology and the templating of specific structures via interactions with membranes has applications in bio-inspired materials. High resolution molecular level studies of the interactions of proteins with membranes could lead to the design of better anti-bacterial agents and the development of novel materials. Unfortunately, investigators have been forced to use relatively crude mimics of biological membranes that do not capture critical aspects of natural cell membranes. In particular, natural cell membranes are asymmetric in the sense that the inside layer of the membrane has a different composition than the outside layer. This effect has important consequences for their behavior. This project will exploit recent technical breakthroughs to study the interactions of a representative member of an important class of human proteins with realistic asymmetric model membranes. The research will provide an unprecedented high resolution view of how proteins interact with biological membranes and induce cell death. The project includes significant efforts devoted to training the next generation of STEM students including initiatives designed to increase undergraduate participation in research and to promote women in the STEM disciplines. The project will define the principles of membrane-catalyzed aggregation of intrinsically disordered polypeptides (IDPs) using biologically relevant asymmetric membranes with a focus on the amyloidogenic polypeptide IAPP. The aggregation of polypeptides on membranes is a general feature of amyloid fiber formation and likely plays a role in the function of certain anti-microbial polypeptides. Unfortunately, existing model membranes are very poor mimics of the relevant plasma membranes. This has hindered biophysical studies of membrane induced self-assembly and membrane activity, making it exceptionally challenging to connect high resolution biophysical studies with the situation in vivo. This project will use asymmetric membranes with physiologically relevant lipid composition and cholesterol together with new methods to probe protein aggregation at high resolution. IAPP is chosen as a model system because it is broadly representative of amyloid formation by IDPs and because of the wealth of biochemical, biophysical and biological data available for this system. The principles that emerge from the research will be applicable to a wide range of systems including other amyloidogenic proteins and anti-microbial peptides. This project is supported by the Molecular Biophysics Cluster of the Division of Molecular and Cellular Biosciences Division in the Biological Sciences Directorate.