Structural dynamics underlying GPCR-G protein selectivity

总结： 标题：GPCR-G蛋白选择性的结构动力学基础 在与具有不同功效的激动剂结合后，G蛋白偶联受体（GPCR）介导 通过与不同亚型的G蛋白偶联实现多种信号通路。某些激动剂表现出 它们对特定G蛋白信号传导途径的功效的选择性。这样的配体提供精确的 与今天的GPCR靶向药物相比，作为药物具有更少的副作用的治疗益处。那里 是非常少的选择性配体已知的特定G蛋白信号传导途径，因为设计这样的 激动剂是一个令人生畏的实验挑战。这是由于严重缺乏了解如何 当GPCR与不同类型的蛋白质结合时，GPCR调节其对其同源G蛋白的功能选择性。 激动剂和细胞中。在过去的三年里，使用多尺度分子动力学的组合， (MD)方法和基因编码的FRET传感器，我们已经表明，GPCR具有潜在的细胞内 可以重塑并与不同的G蛋白结合的空腔。通过重组G蛋白和GPCR 我们已经确定了GPCR-G-蛋白质界面中的热点残基，它们作为“QR码”， 通过GPCR的G蛋白选择性偶联。虽然很明显，来自大脑皮层的变构通讯 G蛋白偶联位点的配体结合位点在G蛋白选择性中的作用知之甚少 关于这种交流的机制以及参与这一过程的残留物。这里我们 建议（1）使用计算方法Allosteer在我们的实验室开发结合FRET 传感器、NanoBRET测定和基于细胞的下游测定，以描绘 参与调节9种不同Gs、Gi和Gq偶联A类中G蛋白选择性的GPCR残基 细胞条件下的GPCR。第二个目的是了解部分激动剂在 与完全激动剂相比，GPCR-G-蛋白选择性偶联。我们将确定热点 当与部分激动剂结合时，G蛋白和GPCR上的残基，并比较相似性， 与完全激动剂的区别。拟议工作的结果将提供变构的作用， G蛋白选择性中的残基网络以及部分激动剂如何调节受体 构象这将推动我们对GPCR如何在生物过程中发挥作用的理解。 在活细胞中识别它们的同源G蛋白。

Summary: Title: Structural dynamics underlying GPCR-G protein selectivity Upon binding to agonists with different efficacies, G protein-coupled receptors (GPCRs) mediate multiple signaling pathways by coupling to different subtypes of G proteins. Certain agonists exhibit selectivity in their efficacy to specific G-protein signaling pathways. Such ligands provide precise therapeutic benefits with fewer side effects as drugs compared to today's GPCR-targeted drugs. There are very few selective ligands known for specific G-protein signaling pathways because designing such agonists is a daunting experimental challenge. This is due to serious lack of understanding of how GPCRs modulate their functional selectivity for their cognate G-protein when bound to different type of agonists and in cells. In the past three years using a combination of multiscale molecular dynamics (MD) method and genetically coded FRET sensors we have shown that GPCRs have latent intracellular cavities that can reshape and couple to different G-proteins. By reengineering G-proteins and GPCRs we have identified the hotspot residues in the GPCR-G-protein interface that serve as the “QR code” for G-protein selective coupling by GPCRs. Although it is clear that allosteric communication from the ligand binding site to the G-protein coupling site plays a role in G-protein selectivity very little is known about the mechanism of this communication and the residues involved in this process. Here we propose to (1) use the computational method Allosteer developed in our lab in combination with FRET sensors, NanoBRET assays and cell based downstream assays to delineate the allosteric network of GPCR residues involved in regulating G-protein selectivity in 9 different Gs, Gi and Gq coupled class A GPCRs in cellular conditions. The second aim is to understand the effect of partial agonists in comparison to the full agonists, on the GPCR-G-protein selective coupling. We will identify the hotspot residues on the G-protein and GPCRs when bound to partial agonists and compare the similarities and differences with full agonists. The outcome of the proposed work will provide the role of allosteric network of residues in G-protein selectivity and how partial agonists modulate the receptor conformations. This will push forward our understanding of the biological process of how GPCRs recognize their cognate G-proteins in live cells.