Post-translational control mechanisms of the circadian clock

生物钟的翻译后控制机制

• 批准号: 8036090
• 负责人: DAVID E SOMERS
• 金额: $ 29.26万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-03-01 至 2015-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8036090
• 关键词: Address; Arabidopsis; Biological Models; Cell Cycle; Cell Nucleus; Circadian Rhythms; Client; Clock protein; Complex; Eukaryota; F-Box Proteins; Feedback; Gatekeeping; Genes; Genetic Transcription; Heat-Shock Proteins 90; Individual; Intracellular Transport; Lead; Link; Maintenance; Malignant Neoplasms; Messenger RNA; Modeling; Molecular; Nuclear; Nuclear Import; Nuclear Pore; Periodicity; Phase; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Play; Process; Proteins; Recruitment Activity; Regulation; Role; Structure; System; Time; Translations; Validation; base; chaperonin; circadian pacemaker; design; heuristics; mRNA Export; mathematical model; molecular phenotype; mutant; nectin; novel; novel strategies; nucleocytoplasmic transport; protein protein interaction; public health relevance; transcription factor

DESCRIPTION (provided by applicant): This proposal is designed to investigate three different post-translational mechanisms of circadian clock control in Arabidopsis. The first is the role of protein phosphorylation, and the effect on activity, localization and stability of key clock proteins. Robust-phase specific phosphorylation of five key proteins in the Arabidopsis clock raises the question of its significance in their activity, localization and turnover. We will focus on the first validated phosphorylation-dependent protein-protein interaction in the Arabidopsis clock to begin to understand the dynamics of TOC1 and PRR3 post-translationally. Additionally, we propose a novel approach to discovering new kinases and phosphatases that act on clock proteins. We also propose to begin modeling this portion of the circadian system to address circuitry of the clock that is not based on transcription. The second is the effect chaperonins play in the maturation of the F-box protein ZEITLUPE to its functional state, necessary to the maintenance of robust circadian amplitude and period. We have identified two components new to any circadian system which likely contribute to ZTL maturation. Through effects on ZTL, these two components indirectly regulate the circadian system. The role of these two proteins in obtaining fully active ZTL, and their potential interaction is the underlying question addressed. The third mechanism is the role of the nuclear pore in the regulation of nuclear import/export of mRNA and/or protein of clock genes. The nuclear pore acts as a gatekeeper to the nucleus and all transcription factors and other regulators of nuclear function must pass through this highly complex structure. All eukaryotic circadian systems involve nucleocytoplasmic shuttling of mRNA and protein which may contribute substantially to establishing the timing delays necessary to establishing a 24 h molecular periodicity. We have identified a nuclear pore component that slows the circadian clock when absent. Understanding the molecular basis of this delay should lead to a greater understanding of how circadian timing is tied to intracellular transport. In a related way, the TOC1/PRR5 interaction appears to facilitate TOC1 nuclear entry and may also serve to recruit a kinase to the interaction. The molecular basis of this interaction and the effect on period will lead to increased understanding of the role of regulated nuclear entry in the clock. While the early heuristic models of the clock focused on transcription/translation feedback loops, recent findings across all circadian systems have highlighted the inadequacy of this view and how post- translational mechanisms contribute substantially to sustaining circadian oscillation. The studies described below will contribute to a greater understanding of circadian clock in particular, and to oscillatory feedback systems in general. PUBLIC HEALTH RELEVANCE: Circadian rhythms control a wide variety of processes in all eukaryotes, including recent linkages to the cell cycle and cancer. The fundamental organization of the clock as consisting of two or more, linked autoregulatory feedback loops is shared among all model systems, but the individual molecular players often vary among the kingdoms. Here post-translational mechanism of circadian clock control in Arabidopsis is investigated, with potential relevance to other eukaryotic oscillatory systems.

描述（由申请人提供）：本提案旨在研究拟南芥中生物钟控制的三种不同的翻译后机制。首先是蛋白质磷酸化的作用，以及对关键时钟蛋白的活性、定位和稳定性的影响。拟南芥时钟中五种关键蛋白的强相特异性磷酸化提出了其在其活性、定位和更新中的重要性的问题。我们将重点关注拟南芥时钟中第一个经过验证的磷酸化依赖性蛋白质-蛋白质相互作用，以开始了解 TOC1 和 PRR3 翻译后的动态。此外，我们提出了一种新方法来发现作用于时钟蛋白的新激酶和磷酸酶。我们还建议开始对昼夜节律系统的这一部分进行建模，以解决不基于转录的时钟电路。 第二个是伴侣蛋白在 F-box 蛋白 ZEITLUPE 成熟到其功能状态的过程中所发挥的作用，这对于维持稳健的昼夜节律幅度和周期是必需的。我们已经确定了任何昼夜节律系统中的两个新成分，它们可能有助于 ZTL 的成熟。通过对 ZTL 的影响，这两个成分间接调节昼夜节律系统。这两种蛋白质在获得完全活性的 ZTL 中的作用以及它们潜在的相互作用是要解决的根本问题。 第三个机制是核孔在调节时钟基因的mRNA和/或蛋白质的核输入/输出中的作用。核孔充当细胞核的看门人，所有转录因子和其他核功能调节因子都必须通过这个高度复杂的结构。所有真核昼夜节律系统都涉及 mRNA 和蛋白质的核细胞质穿梭，这可能对建立建立 24 小时分子周期性所需的时间延迟做出重大贡献。我们发现了一种核孔成分，当其缺失时，它会减慢生物钟。了解这种延迟的分子基础应该有助于更好地了解昼夜节律与细胞内运输的关系。以一种相关的方式，TOC1/PRR5 相互作用似乎促进 TOC1 进入核，并且还可能有助于招募激酶参与相互作用。这种相互作用的分子基础和对周期的影响将导致人们更加了解受调节的核进入在时钟中的作用。 虽然早期的时钟启发式模型侧重于转录/翻译反馈循环，但所有昼夜节律系统的最新发现都强调了这种观点的不足，以及翻译后机制如何对维持昼夜节律振荡做出重大贡献。下面描述的研究将有助于更好地理解特别是生物钟，以及一般的振荡反馈系统。 公共卫生相关性：昼夜节律控制着所有真核生物的多种过程，包括最近与细胞周期和癌症的联系。时钟的基本组织由两个或多个相互连接的自动调节反馈回路组成，在所有模型系统之间共享，但单个分子参与者在各个王国之间通常有所不同。这里研究了拟南芥生物钟控制的翻译后机制，其与其他真核振荡系统具有潜在的相关性。