G PROTEIN BETA GAMMA SIGNALING SYSTEMS IN VIVO

描述(调查人员摘要)；在大多数情况下，不知道 受体激活哪些G蛋白来调节体内的哪些效应器。 重建方法已经开始提供宝贵的信息 特定G蛋白α或β-γ亚基相互作用的可能性 在体外与特定的受体或效应器结合。然而，很明显， 有更广泛的潜在相互作用发生在 重组系统比实际发生在自然膜或细胞内的系统更多 系统。这一发现的例证是β-肾上腺素能受体 在重新构建的系统中同等地激活Gs和Gi，而此 受体只在完整的心肌细胞系统中激活Gs。从… 这些和其他研究，已经变得越来越清楚，尽管一个 受体在体外可以激活几种类型的G蛋白，信号转导 受体在体内调节的途径受到更多的限制。这 表明信号组件和/或人工的 已经在体外使用的检测系统不提供条件 有必要区分什么可能微妙，但重要，机械 在体内工作的信号组件之间的差异。的确有 越来越多的证据表明，这些机械差异不仅反映了 生物化学，但也有空间差异，信号成分之间。 因此，将功能作用归因于G蛋白α和β-伽马 体内的亚基仍然是一项关键而艰巨的任务。这件事的重点是 应用程序是关于开发和应用新的方法，以允许 特定的β-γ二聚体在特定受体-效应器中的作用 途径有待在体内确定。多种方法，包括反向 将采取遗传学、生化和免疫学策略。 使用所有这些方法验证结果将提供强有力的 支持特定受体中特定的β-伽马二聚体的作用 信号通路。

DESCRIPTION (Investigator's Abstract); In most cases, it is not known which receptors activate which G proteins to modulate which effectors in vivo. Reconstitution approaches have begun to provide invaluable information on the potential of specific G protein alpha or beta-gamma subunits to interact with particular receptors or effectors in vitro. Nevertheless, it is clear that there is a far wider range of potential interactions that occur in reconstituted systems than actually do occur in native membrane or cellular systems. This is exemplified by the finding that beta-adrenergic receptor activates both Gs and Gi equally in a reconstituted system, whereas this receptor activates Gs exclusively in an intact cardiac cell system. From these and other studies, it has become increasingly clear that although a receptor can activate several types of G proteins in vitro, the signaling pathways that the receptor regulates in vivo is much more restricted. This suggests that homology among signaling components and/or the artificial assay systems that have been employed in vitro do not provide the conditions necessary to distinguish what may be subtle, but important, mechanistic differences among signaling components that operate in vivo. There is increasing evidence that these mechanistic differences reflect not only biochemical, but also spatial differences, among signaling components. Hence, ascribing functional roles for G protein alpha and beta-gamma subunits in vivo remains a critical and formidable task. The focus of this application is on the development and application of new approaches to allow the role of the specific beta-gamma dimer in a particular receptor-effector pathway to be determined in vivo. Multiple approaches, including reverse genetics, biochemical, and immunological strategies, will be taken. Validation of results with all of these approaches will provide strong support for the role of a specific beta-gamma dimer in a particular receptor signaling pathway.