Novel roles of IKK complex to program gene expression

IKK 复合物在基因表达编程中的新作用

• 批准号: 6940725
• 负责人: KENNETH B MARCU
• 金额: $ 32.14万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6940725
• 关键词: DNA binding protein; I kappa B beta; biological signal transduction; cell cycle; cell growth regulation; chromosomes; cytokine; gene expression; gene induction /repression; laboratory mouse; microarray technology; mutant; nuclear factor kappa beta; polymerase chain reaction; protein structure function; stress; transcription factor

The NF-KappaB inducing IKK signalsome complex is the final receiver and integrator of a host of extracellular stress-like and inflammatory response stimuli. The IKK complex consists of two serinelthreonine kinases (IKKalpha and IKKbeta) and a con-catalytic regulatory/docking protein (NEMO/IKKy). IKK(3 and NEMO/IKKgamma are essential for inducing NF-KB nuclear translocation and DNA binding activity in response to mediators of inflammatory responses like TNFalpha and IL-1, while IKKalpha is largely believed to be dispensible for activating NF-KappaB by these stimuli. Surprisingly, we have recently found that IKKalpha is essential for inducing the transcriptional competence of nuclear NF-KappaB subunits in response to inflammatory cytokines, implying that it plays a critical role in activating NF-KB independent of its DNA binding activity. Consequently, one aim of this proposal will be to elaborate the molecular requirements and mechanisms of action of IKKalpha as a co-global mediator (along with IKKbeta and NEMO/IKKgamma) of stress-like responses culminating in NF-kappaB activation. We have also discovered that the IKK signalsome simultaneously co-ordinates the global induction and repression of cellular gene expression. In a second aim we will elaborate the mechanisms of action of the IKK signalsome as a mediator of NF-KappaB dependent gene repression. We have hypothesized that IKK mediated NF-KappaB activation operates like a co-ordinately controlled on/off switch that alters physiological responses in vivo. Interestingly a subset of the genes, which are repressed in response to extracellular stimulus dependent and IKK mediated NF-KB activation, are also induced targets of the E2F-I. E2F-1 is capable of inducing cell cycle arrest, apoptosis and cell cycle progression depending on its degree of activation and the physiological state of the cell. Experimental conditions in primary and established cells will be established, which lead to interference between NF-KB and E2F on specific genomic targets. The physiological effects of IKK/NF-KappaB mediated repression of cell cycle regulated, E2F target genes will also be evaluated.

NF-KappaB 诱导 IKK 信号复合体是许多细胞外应激样和炎症反应刺激的最终接收者和整合者。 IKK 复合物由两种丝氨酸和苏氨酸激酶（IKKalpha 和 IKKbeta）和一个共催化调节/对接蛋白 (NEMO/IKKy) 组成。 IKK(3 和 NEMO/IKKgamma 对于诱导 NF-KB 核易位和 DNA 结合活性以响应 TNFα 和 IL-1 等炎症反应介质至关重要，而 IKKα 在很大程度上被认为对于通过这些刺激激活 NF-KappaB 来说是可有可无的。令人惊讶的是，我们最近发现 IKKalpha 对于诱导 NF-κB 核易位和 DNA 结合活性至关重要。 核 NF-KappaB 亚基响应炎症细胞因子的转录能力，这意味着它在激活 NF-KB 中发挥着关键作用，独立于其 DNA 结合活性。因此，该提案的一个目的是详细阐述 IKKalpha 作为最终导致 NF-kappaB 激活的应激样反应的共同全局调节剂（与 IKKbeta 和 NEMO/IKKgamma 一起）的分子要求和作用机制。 我们还发现 IKK 信号小体同时协调细胞基因表达的整体诱导和抑制。第二个目标是阐述 IKK 信号小体作为 NF-KappaB 依赖性基因抑制介质的作用机制。我们假设 IKK 介导的 NF-KappaB 激活就像一个协调控制的开关，改变体内的生理反应。有趣的是，这些基因的一个子集（它们因细胞外刺激依赖性和 IKK 介导的 NF-KB 激活而受到抑制）也是 E2F-I 的诱导靶点。 E2F-1 能够诱导细胞周期停滞、细胞凋亡和细胞周期进展，具体取决于其程度 细胞的激活和生理状态。将建立原代细胞和已建立细胞的实验条件，这会导致 NF-KB 和 E2F 对特定基因组靶点的干扰。还将评估 IKK/NF-KappaB 介导的细胞周期调节 E2F 靶基因抑制的生理效应。