Genetic Biochemical Studies of Plant Steroid Signaling

修改后的项目摘要/摘要部分 该项目的长期目标是了解激素、环境因素和营养物质共同控制植物生长和发育的分子网络。植物已经进化出强大的细胞信号系统，根据内部状态和环境条件调节生长和新陈代谢。剖析这些植物调控系统不仅对食品安全和环境可持续性很重要，而且对理解细胞调控也很重要，因为许多机制在动植物中高度保守。这项研究计划集中在类固醇激素油菜素类固醇(BR)影响的细胞信号和调控网络，BR是一种主要的促进生长的激素，影响广泛的发育和生理过程。在拟南芥模型系统中，我们结合遗传、基因组、生化和蛋白质组的方法，阐明了BR与受体激酶BRI1结合导致转录因子BZR1激活的分子机制，该机制通过进化上保守的BSU1磷酸酶和GSK3样激酶家族来实现。此外，我们还在分子水平上揭示了BR信号通路如何与许多其他信号通路整合成调控网络，这些网络控制着驱动细胞伸长的基因转录程序和各种特定的发育程序。我们正在进行的研究揭示了许多翻译后机制，通过这些机制，BR信号通过直接的蛋白质-蛋白质相互作用和翻译后修饰直接调节细胞重组和代谢程序。我们建议将重点放在这些将信号通路与主要的细胞活动联系起来的机制上，如膜运输、细胞分裂和碳代谢。此外，我们将研究BR信号如何与其他信号途径相互作用，以平衡新陈代谢和生长需求，并在植物发育过程中规划细胞分化。这项提案中概述的研究将继续使用遗传学和蛋白质组学方法的组合，并将极大地促进我们对细胞信号整合和信息处理的分子机制的理解。

Modified Project Summary/Abstract Section The long-term goal of this project is to understand the molecular networks through which hormones, environmental factors, and nutrients together control plant growth and development. Plants have evolved robust cellular signaling systems to regulate growth and metabolism according to internal status and environmental conditions. Dissecting these plant regulatory systems is important not only for food security and environmental sustainability, but also for understanding cellular regulation in general, as many mechanisms are highly conserved in animals and plants. This research program focuses on the cellular signaling and regulatory network impinged upon by the steroid hormone brassinosteroid (BR), a major growth-promoting hormone that impact a wide range of developmental and physiological processes. Using a combination of genetic, genomic, biochemical, and proteomic approaches in the Arabidopsis model system, we have elucidated molecular mechanisms by which BR binding to receptor kinase BRI1 leads to activation of transcription factor BZR1 through the evolutionarily conserved BSU1 family of phosphatases and GSK3-like kinases. Furthermore, we have revealed at molecular level how the BR signaling pathway is integrated with many other signaling pathways into regulatory networks that control gene transcription program driving cell elongation and various specific developmental programs. Our ongoing research has uncovered many posttranslational mechanisms by which BR signaling directly modulates cellular reorganization and metabolic programs through direct protein-protein interactions and posttranslational modifications. We proposed to focus on these mechanisms that link signaling pathways with major cellular activities such as membrane trafficking, cell division, and carbon metabolism. In addition, we will investigate how BR signaling cross talks with other signaling pathways to balance metabolism with growth demand and to program cellular differentiation in plant development. The research outlined in this proposal will continue to use combinations of genetic and proteomic approaches and will significantly advance our understanding of the molecular mechanisms of cellular signal integration and information processing.