Interaction of Amyloidogenic Proteins with Asymmetric Membranes

许多重要的生物过程涉及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质杀死细菌的过程中起到了作用。在阿尔茨海默病等淀粉样变性疾病中，它们也可能在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，通过与膜相互作用来模板化特定结构在生物启发材料中得到了应用。蛋白质与膜相互作用的高分辨率分子水平研究有助于设计更好的抗菌剂和开发新材料。不幸的是，研究人员被迫使用相对粗糙的生物膜模拟物，而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，因为膜的内层与外层具有不同的组成。这种影响对他们的行为有重要的影响。这个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中具有代表性的成员与真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角。该项目包括致力于培训下一代STEM学生的重大努力，包括旨在增加本科生参与研究和提高妇女在STEM学科中的地位的倡议。该项目将确定膜催化聚集固有无序多肽(IDPs)的原理，使用与生物相关的不对称膜，重点是淀粉样多肽IAPP。多肽聚集在膜上是淀粉样纤维形成的一般特征，可能在某些抗微生物多肽的功能中发挥作用。遗憾的是，现有的模型膜很难模拟相关的质膜。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格外具有挑战性。这个项目将使用具有生理上相关的脂质成分和胆固醇的不对称膜，以及新的方法来探测高分辨率的蛋白质聚集。IAPP被选为模型系统是因为它广泛代表了国内流离失所者淀粉样蛋白的形成，而且该系统拥有丰富的生化、生物物理和生物学数据。这项研究得出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多肽。该项目得到生物科学局分子和细胞生物科学司分子生物物理学组的支持。

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.