Heterotrimeric G Protein Signaling in Arabidopsis

描述（由申请人提供）：在大多数后生动物中， 异源三聚体G蛋白复合物偶联许多不同的上游信号， 不同的下游效应物，如腺苷酸环化酶、离子通道和 磷脂酶然而，在拟南芥中， 异源三聚体G蛋白复合物，尽管如此，它控制不同植物 应答我们不知道这是如何实现的，也不知道这是什么。 受体激活这种G蛋白复合物。我的最新技术进展 使用功能获得和功能丧失方法来理解 拟南芥G蛋白亚基的功能将使我们能够确定 这种G蛋白复合物在各种信号通路中的分子作用。那里 是这个项目的三个重点领域：生长素控制根的发育， 下胚轴发育和种子萌发的多信号控制。 具体来说，我们将：1。测定G蛋白突变体的生长素反应性 和过表达器并检查信号串扰控制种子 发芽，2.确定和表征遗传和物理相互作用， 使用包括激活的基因外抑制筛选的G α和G β 诱变和使用胞质蛋白质-蛋白质相互作用测定，和3.测试 使用反向遗传学的一小组候选GPCR的推定功能 接近。总之，目标是检验生长素利用 异源三聚体G蛋白在信号转导中的作用。这项工作还解决了一个 信号串扰机理的长期问题。因为， 拟南芥异源三聚体G蛋白似乎是多重信号的中心 利用拟南芥进行的遗传研究可能揭示了 信号集成，这可能是普遍共享的。

DESCRIPTION (provided by applicant): In most metazoans, different heterotrimeric G protein complexes couple many different upstream signals to different downstream effectors such as adenyl cyclase, ion channels, and phospholipases. However, in Arabidopsis, there is only a single canonical heterotrimeric G protein complex that nonetheless controls different plant responses. We do not know how this is accomplished nor do we know what receptors activate this G protein complex. Recent technical advances from my group using both gain- and loss-of-function approaches to understand the function of Arabidopsis G protein subunits will enable us to determine the molecular role of this G protein complex in various signaling pathways. There are three focus areas for this project: auxin control of root development, hypocotyl development; and multi-signal control of seed germination. Specifically, we will: 1. determine auxin responsiveness of G protein mutants and overexpressors and examine the signal cross-talk controlling seed germination, 2. identify and characterize genetic and physical interactors of Galpha and Gbeta using extragenic suppressor screens including activation mutagenesis and using cytosolic protein-protein interaction assays, and 3. test putative functions of a small set of candidate GPCRs using reverse genetic approaches. In summary, the goal is to test the hypothesis that auxin utilizes heterotrimeric G proteins in signal transduction. This work also addresses a longstanding problem on the mechanism of signal cross-talk. Because, the single Arabidopsis heterotrimeric G protein appears to be central to multiple signal pathways, genetic studies using Arabidopsis may reveal the core mechanism of signal integration, which is likely to be shared universally.