Allosteric Regulation of Human G Protein-Coupled Receptors by Membrane Lipids

项目摘要/摘要 我们研究计划的长期目标是在原子水平上理解 脂类调节人G蛋白偶联受体(GPCR)活性的机制 了解GPCRs如何影响其周围的膜环境。GPCR推动了许多 并代表最大的“可用药”蛋白质靶标家族。药物结合 和gpr信号都受周围细胞环境的变构调节，通过 受体-脂质相互作用。这种膜-蛋白质相互作用在细胞内普遍存在， 在生理学中的作用有很好的文献记载，然而，对结构机制知之甚少 膜通过它调节gpr的功能。解决这一知识差距的需要是 最近的研究将gpr-脂质相互作用与细胞特异性药物联系起来，这一点得到了加强 反应和揭示gpr-脂质相互作用在广泛的疾病中的关键作用， 包括阿尔茨海默氏症、癌症和心脏病。我们的研究将捕捉到不同 脂类调节gpr功能的作用，既作为特定的化学伙伴，也通过整体 脂类的物理和化学性质，通过整合独特的溶液和固体能力 核磁共振(核磁共振)与其他生物物理工具和相关功能 化验。最初的努力针对两条线进行调查，旨在解决大多数 关于受体-脂质相互作用的直接和重要的问题。首先，我们将确定 脂质如何调节A2A腺苷受体(A2AAR)的药物结合和信号转导 具有代表性的GPCR型，具有许多共同的结构和功能特征 视紫红质样受体。这些研究将揭示脂类如何影响蛋白质动力学，改变激活 “热点”，并调节信号复合体的形成。将这些新数据与可用的 药理学和晶体结构将为解释细胞- 特定的药物反应。在第二个方向，我们将通过以下方式确定结构机制 哪些膜脂变构地调节平滑受体(SMO)的信号，a 刺猬信号蛋白和有效的癌症靶点。SMO在初级纤毛中的功能，专门化 细胞器充满了感觉蛋白质，起到了细胞“天线”的作用。一个新兴的概念是 睫状膜的组成是微调的受体功能，但实际上知之甚少 睫状膜中受体-脂质相互作用的特性。我们的工作将首次揭示 特定的脂类和整体脂类如何调节SMO信号复合体。加在一起，这些 研究路线将揭示脂质介导的变构的基本原理，并为长期 将这些原则应用于设计针对特定受体-脂质相互作用的药物的学期努力。

PROJECT SUMMARY/ABSTRACT The long term goal of our research program is to understand at an atomic level the mechanisms by which lipids regulate human G protein-coupled receptor (GPCR) activity, and in turn learn how GPCRs influence their surrounding membrane environment. GPCRs drive many physiological processes and represent the largest family of “druggable” protein targets. Drug binding and GPCR signaling are both allosterically regulated by the surrounding cellular environment through receptor-lipid interactions. Such membrane-protein interactions are ubiquitous within the cell and have well documented roles in physiology, however, little is known about the structural mechanisms by which membranes regulate GPCR function. The need to address this gap in knowledge is heightened by more recent studies associating GPCR-lipid interactions with cell-specific drug responses and revealing critical roles of GPCR-lipid interactions in a wide range of diseases, including Alzheimers’ disease, cancers, and heart disease. Our research will capture the different roles by which lipids regulate GPCR function, both as specific chemical partners and through the bulk physical and chemical properties of lipids, by integrating unique capabilities of solution and solid state nuclear magnetic resonance (NMR) with additional biophysical tools and correlative functional assays. Initial efforts are directed at two lines of investigation aimed at addressing the most immediate and important questions regarding receptor-lipid interactions. In the first, we will determine how lipids modulate drug binding and signal transduction for the A2A adenosine receptor (A2AAR), a representative model GPCR that shares structural and functional characteristics with many rhodopsin-like receptors. These studies will reveal how lipids impact protein dynamics, alter activation “hotspots”, and regulate formation of signaling complexes. Integrating this new data with available pharmacology and crystal structures will provide a new conceptual framework for interpreting cell- specific drug responses. In the second direction, we will determine the structural mechanisms by which membrane lipids allosterically modulate signaling of the smoothened receptor (SMO), a hedgehog signaling protein and validated cancer target. SMO functions in primary cilia, specialized organelles packed with sensory proteins that act as cellular “antenna”. An emerging concept is that ciliary membrane composition is fine-tuned for receptor function, yet little is actually known about the properties of receptor-lipid interactions in ciliary membranes. Our work will reveal for the first time how both specific lipids and bulk lipid properties regulate SMO signaling complexes. Together, these lines of investigation will reveal basic principles of lipid-mediated allostery and set the stage for long term efforts to apply these principles to design drugs targeting specific receptor-lipid interactions.