Regulation of CBP by Synaptic Activity

突触活动对 CBP 的调节

• 批准号: 6418693
• 负责人: SOREN IMPEY
• 金额: $ 12.97万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-01-07 至 2005-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6418693
• 关键词: biological signal transduction; cAMP response element binding protein; calcium flux; genetic regulation; genetic transcription; laboratory mouse; neurophysiology; phosphorylation; protein kinase A; synapses

DESCRIPTION (provided by applicant): Activity-regulated gene expression plays a fundamental role in both the remodeling of synaptic circuitry and in neuronal survival. Activity-dependent increases in intracellular Ca2+ trigger the expression of hundreds or perhaps thousands of genes. The cAMP response element (CRE) was identified as a major Ca2+ responsive element via analysis of immediate early gene (IEGs) promoters and many if not most Ca2+ responsive promoters contain CREs. The basic leucine zipper transcription factor, CREB, binds to the CRE as a dimer and can be activated by Ca2+, cAMP/PKA, and growth factor signaling pathways. The transcription factor CREB is a major target of activity-induced Ca2+ influx and is a key regulator of both neuronal survival and adaptive synaptic plasticity. Nevertheless, the mechanisms by which Ca2+ activates CREB have not been clearly elucidated. It is well established that PKA phosphorylates Ser 133 of CREB and creates a phospho-serine docking motif that recruits its coactivator CBP (or the homologue, p300). Recruitment of CBP is thought to enhance transcriptional activation either via its association with the general transcriptional machinery or via its intrinsic histone acetyltransferase activity. Although activity-induced Ca2+ influx is widely believed to regulate CREB function in an analogous manner, the signaling cascades that promote CBP recruitment and transcriptional activation have not been clearly defined. A major theme of this proposal is to determine whether the PKA-CREB-CBP paradigm also pertains to Ca2+-activated transcription. Thus, an initial goal of this study will be to determine whether neuronal activity induces the recruitment of CBP to CREB and whether CBP recruitment is required for transcriptional activation. Four specific aims are proposed. (1) Determine whether synaptic activity induces the recruitment of CBP to CREB in neurons and whether recruitment of CBP is sufficient for full transcriptional activation. (2) Decipher the activity-regulated signaling cascades that promote the phosphorylation and activation of CREB and CBP. (3) Determine how synaptic activity and Ca2+ influx regulate CBP function. (4) Analyze the regulation of CBP and CREB function in mice deficient for CaM kinase IV. This study seeks to dissect the biochemical events result in synaptic activity-mediated phosphorylation of CREB, recruitment of CBP, and "activation" of CBP-dependent transcription. Gaining insight into the mechanisms of activity-mediated transcription has relevance in the treatment of neurodegenerative pathologies that may result from excitotoxic cell death or apoptosis. Through a mentored career development plan, the Principal Investigator will gain an enhanced capacity to be productive in the field of molecular neurobiology with a focus on gene regulation. This will be accomplished by conducting the above described research, attending and presenting at local and national seminars and meetings, and participating in courses teaching molecular biology and neurophysiology techniques.

描述（由申请人提供）： 活性调节的基因表达在这两个方面都起着重要作用 突触回路的重塑和神经元的存活。活动依赖性 细胞内 Ca2+ 的增加会触发数百种或可能的表达 数千个基因。 cAMP 反应元件 (CRE) 被确定为主要的 通过立即早期基因 (IEG) 启动子分析的 Ca2+ 响应元件 许多（如果不是大多数）Ca2+ 响应启动子都含有 CRE。碱性亮氨酸 拉链转录因子 CREB ​​以二聚体形式与 CRE 结合，并且可以 由 Ca2+、cAMP/PKA 和生长因子信号通路激活。这 转录因子 CREB ​​是活动诱导的 Ca2+ 流入的主要靶标 是神经元存活和适应性突触可塑性的关键调节因子。 然而，Ca2+激活CREB的机制尚未明确。 阐明了。众所周知，PKA 磷酸化 CREB ​​的 Ser 133，并且 创建一个磷酸丝氨酸对接基序，招募其共激活剂 CBP（或 同系物，p300）。 CBP 的招募被认为可以增强转录 通过与一般转录的关联激活 机制或通过其内在的组蛋白乙酰转移酶活性。虽然 人们普遍认为，活动诱导的 Ca2+ 内流可以调节 CREB ​​功能 以类似的方式，促进 CBP 募集和的信号级联 转录激活尚未明确定义。 该提案的一个主要主题是确定 PKA-CREB-CBP 是否 该范式还涉及 Ca2+ 激活的转录。于是，最初的目标 这项研究的目的是确定神经元活动是否会诱导 向 CREB ​​招募 CBP 以及是否需要招募 CBP 转录激活。提出了四个具体目标。 (1)确定 突触活动是否会诱导神经元中 CBP 向 CREB ​​的募集以及 CBP 的募集是否足以完全转录激活。 (2) 破译促进活性调节的信号级联 CREB ​​和 CBP 的磷酸化和激活。 (3) 确定突触如何 活性和 Ca2+ 流入调节 CBP 功能。 （四）分析监管 CBP 和 CREB ​​在 CaM 激酶 IV 缺陷的小鼠中发挥作用。这项研究旨在 剖析突触活动介导的生化事件 CREB ​​的磷酸化、CBP 的募集以及 CBP 依赖性的“激活” 转录。深入了解活动介导的机制 转录与神经退行性疾病的治疗相关 这可能是由兴奋性毒性细胞死亡或细胞凋亡引起的。通过辅导 职业发展计划，首席研究员将获得增强的 重点关注分子神经生物学领域的高效能力 关于基因调控。这将通过执行上述操作来完成 研究、参加地方和国家研讨会和会议并在会上发表演讲， 并参加分子生物学和神经生理学课程的教学 技术。