Membrane Control of Protein-Protein Contact. Simulation Based on Phase Diagrams

描述(申请人提供)：病毒侵入所有形式的生命，导致人类疾病，包括艾滋病毒-艾滋病。尽管病毒的种类令人望而生畏，但所有被包膜的病毒，包括HIV-1和劳斯肉瘤病毒(RSV)，都必须与质膜的内叶联系在一起。我们的实验室已经开展了一项大规模的工作，以表征膜组件之间的相互作用。其目的是发现哪些膜因子对膜相关病毒基质蛋白之间的相互作用起到控制作用。总体方法是将实验测量(主要是FRET和荧光显微镜)与蒙特卡罗计算机模拟相结合，以发现脂-脂、脂-蛋白质和蛋白质-蛋白质之间的所有重要相互作用能量。首先在模型脂质体中测量膜相行为和蛋白质-蛋白质相互作用，然后在活的鸡成纤维细胞中测量膜相行为和蛋白质相互作用。第一个具体目标是开发实验和蒙特卡罗模拟，以描述含有胆固醇的简单3种脂类成分混合物中的Granicidin-Granicidin相互作用。第二个目标是处理第五种成分--神经酰胺或二酰甘油--的复杂性大大增加。这一目标包括建议开发一种“脂缓冲”，以控制胆固醇、神经酰胺或二酰甘油在模型或真实生物膜中的化学势。第三个目标是在模拟动物细胞质膜内叶的脂质混合物中表征HIV-1和RSV基质蛋白质-蛋白质的相互作用，作为理解活细胞行为的基础。第四个也是最终的目标是在活细胞中使用FRET检测HIV-1和RSV基质蛋白-蛋白质在质膜内叶的相互作用，试图找到控制相互作用的因素，以及是否观察到与外叶的耦合。对病毒性疾病，特别是艾滋病毒-艾滋病的有效治疗，并不局限于“要么全部治愈，要么全部治愈”。药物组合已被证明是有效的，每一种药物都能延缓病毒生命周期的一个步骤。这项拟议的研究将导致详细了解膜成分胆固醇、神经酰胺和二酰甘油是如何控制病毒生命中的一个关键步骤--在质膜上结合/组装的，所有这些都可以被药物部分调节。

DESCRIPTION (provided by applicant): Viruses invade all forms of life, causing diseases in humans including HIV-AIDS. Although the variety of viruses is daunting, all enveloped viruses, including HIV-1 and Rous Sarcoma Virus (RSV), must associate with the inner leaflet of plasma membranes. Our laboratories have undertaken a large-scale effort to characterize interactions between membrane components. The goal is to discover which membrane factors exert control over the interactions between membrane-associated viral matrix proteins. The overall approach is to combine experimental measurements, mainly FRET and fluorescence microscopy, with Monte Carlo computer simulations in order to discover all of the significant interaction energies between lipid-lipid, lipid-protein, and protein-protein. Membrane phase behavior and protein-protein interactions are first measured in model liposomes and then in live chicken fibroblast cells. The first specific aim is to develop the experiments and Monte Carlo simulations to describe gramicidin-gramicidin interactions in a simple 3-lipid component mixture containing cholesterol. The second aim is to handle the greatly increased complexity of a fifth component, ceramide or diacylglycerol. This aim includes proposed development of a "lipid buffer" in order to control the chemical potential of cholesterol, ceramide, or diacylglycerol in model or real biomembranes. The third aim is to characterize HIV-1 and RSV matrix protein-protein interactions in a lipid mixture that models the inner leaflet of an animal cell plasma membrane, as a basis for understanding behavior in live cells. The fourth and final aim is to examine HIV-1 and RSV matrix protein-protein interactions at the inner leaflet of the plasma membrane using FRET in live cells, attempting to find the factors that control the interactions, and whether coupling to the outer leaflet is observed. Useful treatments for viral afflictions, in particular HIV-AIDS, are not limited to "all or none" cures. Combinations of drugs, each of which slows down a step of the viral life cycle, have proven useful. The proposed research will lead to detailed understanding of how the membrane components cholesterol, ceramide, and diacylglycerol, all of which can be partially regulated by drugs, control one critical step in the life of the virus - association/assembly at the plasma membrane.