Functional Analysis of the Tip60 Complex

Tip60 复合物的功能分析

• 批准号: 8268531
• 负责人: Brendan D Price
• 金额: $ 28.65万
• 依托单位: DANA-FARBER CANCER INST
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-01 至 2014-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8268531
• 关键词: ATM Signaling Pathway; ATP phosphohydrolase; Binding; Bleomycin; Carcinogens; Cell Line; Cells; Chromatin; Chromatin Remodeling Factor; Chromatin Structure; Complex; DNA; DNA Damage; DNA Double Strand Break; DNA Repair; DNA Repair Pathway; DNA lesion; DNA strand break; Detection; Double Strand Break Repair; Environmental Carcinogens; Epigenetic Process; Event; Exposure to; Generations; Genotoxic Stress; Health; Heavy Metals; Higher Order Chromatin Structure; Histone Acetylation; Histones; Indium; Intervention; Link; Lysine; Malignant Neoplasms; Mediating; Mediator of activation protein; Methylation; Mutagens; Mutation; Normal Cell; Phosphotransferases; Process; Production; Property; Protein Acetylation; Proteins; Public Health; Recruitment Activity; Relaxation; Research; Risk; Role; Scaffolding Protein; Signal Transduction; Signal Transduction Pathway; Site; Specificity; Testing; Therapeutic Agents; Tobacco smoke; Ultraviolet Rays; cancer risk; cancer therapy; carcinogenesis; chromatin remodeling; cytotoxicity; design; environmental agent; genetic regulatory protein; histone acetyltransferase; histone methyltransferase; improved; innovation; insight; neoplastic cell; novel; novel therapeutics; programs; repaired; response; stem

DESCRIPTION (provided by applicant): Cancer arises during the process of carcinogenesis, in which the exposure of cells to genotoxic insults leads to the introduction of permanent genetic changes. The ability of cells to detect this DNA damage and to activate appropriate repair mechanisms is crucial for the cell to suppress carcinogenic events. The Tip60 histone acetyltransferase is a key mediator of the cells ability to detect and repair these DNA lesions. Tip60 is a key component of the NuA4-Tip60 chromatin remodeling complex. Chromatin remodeling is utilized to unpack higher ordered chromatin structures and alter histone-DNA interactions to facilitate access of the DNA repair machinery to DNA lesions. Our results demonstrate that chromatin remodeling by the NuA4-Tip60 complex requires Tip60's HAT activity. Further, Tip60 contains a chromodomain, a conserved domain with the potential to interact with methylated lysine residues on histones, and this domain is required for the activation of Tip60's HAT activity and NuA4-dependent chromatin remodeling. The long term aims are to test the hypothesis that Tip60 is a key component of a novel signal transduction pathway which links the detection of DNA damage to alterations in chromatin structure. We will test the hypothesis that the catalytic components of NuA4, including the p400 ATPase activity and Tip60's HAT activity, are required for chromatin remodeling following DNA damage. Further, we propose that interactions between the chromodomain of Tip60 and exposed methyl-lysine residues on histones at sites of DNA damage mediate this activation of Tip60's HAT activity. Tip60 exists as a trimeric complex containing the Tip60, epc1 and ING3 proteins. In specific aim 1, the role of the ING3 regulatory protein in controlling Tip60's HAT activity will be defined, and the mechanism by which NuA4 is recruited to DNA breaks will be determined. In specific aim 2, the function of the ATPase activity of the p400 sub- unit of NuA4 in chromatin unwinding will be determined, and the contribution of histone acetylation by Tip60 at sites of DNA damage identified. In specific aim 3, the specificity of interaction between the chromodomain of Tip60 and methylated lysine residues on histones will be determined, and the role of histone methylation in the DNA-damage dependent activation of Tip60 examined. An understanding of the signal transduction pathway by which Tip60 detects DNA strand breaks caused by bleomycin and related agents will provide crucial insights into the cytotoxicity and mutagenic properties of these agents. A more complete understanding of how Tip60 regulates the DNA damage response may allow new therapies, including the rational design of novel therapeutic compounds, to be applied to cancer therapy and to clinically beneficial interventions for reducing the risk from genotoxic stress. Finally, Tip60 and its associated proteins are potential targets for developing therapeutic agents which can modify the DNA damage response of tumor cells.

描述（由申请人提供）：癌症是在癌变过程中产生的，其中细胞暴露于基因毒性损伤导致引入永久性基因变化。细胞检测这种 DNA 损伤并激活适当修复机制的能力对于细胞抑制致癌事件至关重要。 Tip60 组蛋白乙酰转移酶是细胞检测和修复这些 DNA 损伤能力的关键介质。 Tip60 是 NuA4-Tip60 染色质重塑复合物的关键成分。染色质重塑用于解开更有序的染色质结构并改变组蛋白-DNA 相互作用，以促进 DNA 修复机制接近 DNA 损伤。我们的结果表明，NuA4-Tip60 复合物进行的染色质重塑需要 Tip60 的 HAT 活性。此外，Tip60 包含一个染色质结构域，这是一个保守结构域，有可能与组蛋白上的甲基化赖氨酸残基相互作用，并且该结构域是激活 Tip60 的 HAT 活性和 NuA4 依赖性染色质重塑所必需的。长期目标是检验这样的假设：Tip60 是一种新型信号转导途径的关键组成部分，该途径将 DNA 损伤的检测与染色质结构的改变联系起来。我们将测试这样的假设：NuA4 的催化成分（包括 p400 ATP 酶活性和 Tip60 的 HAT 活性）是 DNA 损伤后染色质重塑所必需的。此外，我们提出 Tip60 的染色质结构域与 DNA 损伤位点组蛋白上暴露的甲基赖氨酸残基之间的相互作用介导了 Tip60 的 HAT 活性的激活。 Tip60 作为包含 Tip60、epc1 和 ING3 蛋白的三聚体复合物存在。在具体目标1中，将定义ING3调节蛋白在控制Tip60的HAT活性中的作用，并且将确定NuA4被募集到DNA断裂的机制。在具体目标 2 中，将确定 NuA4 p400 亚基的 ATP 酶活性在染色质解旋中的功能，并确定 Tip60 在 DNA 损伤位点对组蛋白乙酰化的贡献。在具体目标 3 中，将确定 Tip60 的染色质结构域与组蛋白上甲基化赖氨酸残基之间相互作用的特异性，并检查组蛋白甲基化在 Tip60 的 DNA 损伤依赖性激活中的作用。了解 Tip60 检测博来霉素和相关药物引起的 DNA 链断裂的信号转导途径，将为了解这些药物的细胞毒性和诱变特性提供重要的见解。更全面地了解 Tip60 如何调节 DNA 损伤反应可能会允许新疗法（包括新型治疗化合物的合理设计）应用于癌症治疗和临床有益的干预措施，以降低基因毒性应激的风险。最后，Tip60 及其相关蛋白是开发可改变肿瘤细胞 DNA 损伤反应的治疗剂的潜在靶标。