Roles and Regulation of the bZip Transcription Factor CEBP-1 in Stress Response Pathways

项目摘要 细胞对压力的适当反应对生物体的生存至关重要。大多数细胞应激反应都涉及到 调节应激反应基因表达的转录因子的作用。确定如何转录 因素可以启动对各种压力输入的不同反应，这对于理解多个 人类疾病。这个项目的总体目标是揭示一个单一的 转录因子可以整合多种输入，并指导适当的转录反应。CCAAT 增强子结合蛋白(C/EBP)家族蛋白参与多种形式的应激反应。C/EBPS 含有一个碱性亮氨酸拉链DNA结合域，以及反式激活和调节域，它们调节 通过特定的蛋白质-蛋白质相互作用或翻译后修饰的转录活性。虽然 C/eBP蛋白已被广泛研究，但其在外界刺激下的作用机制尚不清楚。 明白了。利用秀丽线虫的研究为研究多水平的细胞和 机体对压力信号的反应。本提案着重于研究细胞的分子功能。 保守的C/EBP同源物，CEBP-1，在调节发育和神经元应激反应中。在……里面 神经元，CEBP-1在轴突损伤和细胞骨架破坏的反应中起关键作用，作用于下游 DLK-1的MAP激酶级联。在动物发育过程中，CEBP-1由Tribble家族负调控 蛋白，NIPI-3，进而激活不同的MAP激活级联反应。使用强大的正向基因筛查， 我已经在CEBP-1的N-末端确定了一个对其活性至关重要的独特的功能结构域。在这里，我 建议检验这样一种假设，即这个结构域与差异蛋白质-蛋白质相互作用一起赋予 反式激活调节以启动对不同应激输入的转录反应。这项研究的目标是 将通过以下具体目标来实现：目标1：利用IP-1鉴定CEBP-1结合蛋白 并证明N-末端区域具有反式激活活性。目标2：实现 确定NIPI-3对CEBP-1转录调控的机制；目的3：寻找新的基因 NIPI-3/Tribble和CEBP-1途径中的玩家。这项提议的完成将提供更深层次的 了解应激反应对各种外界刺激的一般过程。了解 这种控制的机制可能允许开发针对影响细胞的疾病的靶向治疗 压力反应和修复。

Project Summary Proper cellular response to stress is vital for organismal survival. Most cellular stress responses involve the action of transcription factors that regulate expression of stress response genes. Determining how transcription factors can initiate differential responses to a variety of stressful inputs is critical for understanding multiple human diseases. The overall goal of this project is to uncover the mechanisms by which a single transcription factor can integrate multiple inputs and direct proper transcriptional responses. CCAAT enhancer binding proteins (C/EBP) family proteins are involved in many forms of stress responses. C/EBPs contain a basic-leucine-zipper DNA binding domain, and transactivating and regulatory domains, which modulate transcriptional activity via specific protein-protein interactions or post-translational modifications. Although C/EBP proteins have been extensively studied, the mechanism of their action under external stimuli is still poorly understood. Studies using Caenorhabditis elegans offer great advantages to investigate multi-level cellular and organismal responses to stress signals. This proposal focuses on examining the molecular function of the conserved C/EBP homologue, CEBP-1, in mediating both development and neuronal stress responses. In neurons, CEBP-1 plays critical roles in response to axon injury and cytoskeleton disruption, acting downstream of the DLK-1 MAP kinase cascade. In animal development CEBP-1 is negatively controlled by the Tribbles family protein, NIPI-3, and in turn activates a different MAP kinase cascade. Using powerful forward genetic screening, I have identified a distinct functional domain in the N-terminus of CEBP-1 that is crucial for its activity. Here, I propose to test the hypothesis that this domain, in conjunction with differential protein-protein interaction, endows transactivating regulation to initiate transcriptional responses to different stressful inputs. The goals of this study will be accomplished through the following specific aims: Aim 1: To identify CEBP-1 binding proteins using IP- mass spectrometry and to demonstrate that the N-terminal region contains transactivating activity. Aim 2: To determine the mechanism of transcriptional regulation of CEBP-1 by NIPI-3; and Aim 3: to Identify new genetic players in NIPi-3/Tribbles and CEBP-1 pathway. The completion of this proposal will provide a deeper understanding of the general process of stress response to various external stimuli. Understanding the mechanism of this control could allow for development of targeted treatments for diseases affecting cellular stress response and repair.