Role of Receptor Dimerization in G Protein Activation

描述（由申请人提供）：本提案的长期目标 是为了确定G蛋白偶联受体 将信号传递到细胞中。这些信息将是重要的， 了解细胞信号传导、发育和疾病的基本方面 机制等深入了解这个重要的受体超家族如何作为 配体激活的开关将有助于药物设计， 目前，超过一半的处方药靶向G蛋白偶联 受体。作用于这些受体的新疗法的潜力是巨大的; 估计有3%的人类基因组编码G蛋白偶联受体。 尽管它们具有广泛的重要性，但我们不知道受体是如何 实际上起着配体激活开关的作用。最近的证据表明 G蛋白偶联受体，如肾上腺素和多巴胺受体， 形成同二聚体; 8和K-阿片受体已被证明形成 具有新药理学的异二聚体。我们对受体是否 通过特定的二聚体界面或更大的寡聚体结构相互作用， 受体二聚化/寡聚化的生理意义，如果这 是其他G蛋白偶联受体的一般机制。解决这些 基本问题，该提案采用了各种技术，包括 遗传研究、荧光能量转移、生化交联，以及 计算机模拟这些研究将对人补体进行 因子5（C5 a）受体，一种介导中性粒细胞 趋化性这种受体在酵母中表达时功能良好， C5 a受体可能的高通量结构/功能研究。在 在哺乳动物细胞中的平行研究，从遗传学中获得的信息， 研究将被用于询问关于受体激活的具体问题 如果二聚化/寡聚化在受体中起作用， 功能这些研究应该增加我们对受体的理解 G蛋白信号传导的激活机制。

DESCRIPTION (provided by applicant): The long-term objectives of this proposal are to identify the molecular mechanisms by which G protein-coupled receptors transduce signals into cells. This information will be important for understanding fundamental aspects of cell signaling, development, and disease mechanisms. Insights into how this important receptor superfamily works as ligand-activated switches will aid in drug design and greatly impact medicine more than half of currently prescribed pharmaceuticals target G protein-coupled receptors. The potential for new therapies acting on these receptors is great; an estimated 3 percent of the human genome encodes G protein-coupled receptors. Despite their widespread importance, we do not understand how the receptors actually function as ligand-activated switches. Recent evidence demonstrates that G protein-coupled receptors, such as adrenergic and dopamine receptors, form homodimers; the 8 and K-opiate receptors have been shown to form heterodimers with novel pharmacology. Little is known about if the receptors interact via specific dimer interfaces or larger oligomeric structures, the physiologic significance of receptor dimerization/oligomerization, and if this is a general mechanism for other G protein-coupled receptors. To address these fundamental questions, this proposal employs a variety of techniques including genetic studies, fluorescence energy transfer, biochemical crosslinking, and computer modeling. These studies will be performed on the human complement factor 5 (C5a) receptor, a chemoattractant receptor that mediates neutrophil chemotaxis. This receptor functions well when expressed in yeast, making possible high-throughput structure/function studies on the C5a receptor. In parallel studies in mammalian cells, the information gained from the genetic studies wifl be used to ask specific questions regarding receptor activation mechanisms and if dimerization / oligomerization plays a role in receptor function. These studies should add to our understanding of the receptor activation mechanisms for G protein signaling.