G PROTEIN BETA GAMMA SIGNALING SYSTEMS IN VIVO

描述（研究者摘要）;在大多数情况下， 受体激活哪些G蛋白来调节体内的哪些效应物。 重组方法已开始提供宝贵的信息， 特异性G蛋白α或β-γ亚基相互作用的潜力 与特定的受体或效应器进行体外实验。 然而，很明显， 有一个更广泛的潜在的相互作用发生在 比在天然膜或细胞中实际发生的更容易重构的系统 系统. β-肾上腺素能受体 在重组系统中激活Gs和Gi，而这 受体仅在完整的心脏细胞系统中激活Gs。 从 这些研究和其他研究，越来越清楚地表明，虽然 受体在体外可以激活几种类型的G蛋白， 受体在体内调节的途径受到更多的限制。 这 表明信号传导组分和/或人工合成的蛋白质之间的同源性， 已经在体外使用的测定系统不能提供 有必要区分什么可能是微妙的，但重要的，机械的， 在体内运作的信号成分之间的差异。 有 越来越多的证据表明，这些机制上的差异不仅反映了 生物化学，而且空间差异之间的信号组件。 因此，将G蛋白α和β-γ的功能作用归因于 亚基在体内仍然是一个关键和艰巨的任务。 的重点 应用是关于新方法的开发和应用， 特异性β-γ二聚体在特定受体效应物中的作用 在体内确定的途径。 多种方法，包括反向 将采取遗传学、生物化学和免疫学策略。 所有这些方法的结果验证将提供强有力的 支持特定受体中特定β-γ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.