Role of p300 and hHR23 proteins in p53 regulation

p300 和 hHR23 蛋白在 p53 调节中的作用

• 批准号: 7215281
• 负责人: Steven R. Grossman
• 金额: $ 27.82万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7215281
• 关键词: Acetylesterase; Adaptor Signaling Protein; Address; Alleles; Biochemical; Cells; Colon; Complex; Condition; DNA Damage; Data; Disruption; Dominant-Negative Mutation; EP300 gene; Epithelium; Equilibrium; Face; Family member; Feedback; Gap Junctions; Genomics; Genus Cola; Homeostasis; Human; In Vitro; Ionizing radiation; Knock-in Mouse; MDM2 gene; MDM2 gene; Malignant Neoplasms; Maps; Metabolic Pathway; Metabolism; Neoplastic Processes; Nexus (resin cement); Oncogene Activation; Oncogenes; Oncogenic; Pathway interactions; Physiological; Polyubiquitination; Process; Protein Family; Proteins; Regulation; Role; Signal Transduction; Stress; Structure; Surface; System; TP53 gene; Tumor Cell Line; Tumor Suppression; Tumor Suppressor Proteins; Tumor Tissue; Ubiquitin; Ubiquitination; cell killing; histone acetyltransferase; in vivo; loss of function; malignant breast neoplasm; mouse model; multicatalytic endopeptidase complex; mutant; novel; reconstitution; research study; response; stressor; tumor; ubiquitin ligase

DESCRIPTION (provided by applicant): Experiments in this proposal will attempt to place into biologic context the contributions of p300 and hHR23 proteins to p53 homeostatic regulation by the ubiquitin/proteasome pathway. The p300 coactivator encodes both histone acetylase and ubiquitin ligase functions, and thus acts as a nexus for p53 homeostasis, encoding both positive and negative regulatory functions, p300 interacts with the p53 antagonist and ubiquitin ligase, MDM2, and the two proteins cooperate in the polyubiquitination and rapid proteasome turnover of p53. Under conditions of stress or DNA damage, p300 activates p53 functions through its intrinsic acetylase activity. hHR23 proteasome adaptor proteins also profoundly influence the metabolism and activity of p53 in human cells, hHR23-family proteins protect p53 from degradation, and may integrate ubiquitination and degradation of p53, by forming a complex with MDM2. Moreover, a novel, potentially regulatory or dominant negative third hHR23 family member has been identified which, unlike the known hHR23 family members, is not universally expressed in all cell lines, tumors and tissues. The proposed experimental aims address the specific mechanisms by which p3OO/MDM2 interaction, p300 ubiquitin ligase activity, and hHR23 proteins act as key components in the dynamic physiologic regulation of p53 response to oncogenic stressors, such as ionizing radiation. The role of p300/MDM2 interaction in determining how p300 activity as an activator or antagonist of p53 is balanced, will be examined by mapping of the interaction, and analysis of p53 regulation in cells expressing non-interacting mutant alleles. The specific role of p300 ubiquitin ligase activity in p53 homeostasis will be studied by analysis of loss of function alleles in primary human cells and a knock-in mouse model. The function of the hHR23A and hHR23B proteasome adaptor proteins, and the role of hHR23/MDM2 interaction in p53 regulation, will be analyzed by structure/function analysis of hHR23 proteins in cultured ceils and in a reconstituted in vitro p53 degradation system. A novel, potentially regulatory, hHR23 family member will also be further characterized for its role in DNA damage regulation of p53 stability.

描述（由申请人提供）： 在这个建议中的实验将试图将p300和hHR 23蛋白的贡献，p53稳态调节的泛素/蛋白酶体途径的生物背景。 p300共激活因子编码组蛋白乙酰化酶和泛素连接酶的功能，并因此作为p53稳态的联系，编码积极和消极的调节功能，p300与p53拮抗剂和泛素连接酶，MDM 2相互作用，这两种蛋白质在p53的多聚泛素化和快速蛋白酶体周转合作。 在应激或DNA损伤的条件下，p300通过其内在的乙酰化酶活性激活p53功能。 hHR 23蛋白酶体接头蛋白也深刻地影响p53在人类细胞中的代谢和活性，hHR 23家族蛋白保护p53免于降解，并且可以通过与MDM 2形成复合物来整合p53的泛素化和降解。此外，已经鉴定了一种新的、潜在的调节性或显性负性的第三hHR 23家族成员，其与已知的hHR 23家族成员不同，不是在所有细胞系、肿瘤和组织中普遍表达。 拟议的实验目的解决的具体机制，p300/MDM 2的相互作用，p300泛素连接酶的活性，和hHR 23蛋白作为关键组成部分的动态生理调节p53致癌应激，如电离辐射。p300/MDM 2相互作用在确定p300作为p53的激活剂或拮抗剂的活性如何平衡中的作用，将通过相互作用的作图和表达非相互作用突变等位基因的细胞中p53调节的分析来检查。 将通过分析原代人细胞和敲入小鼠模型中功能等位基因的丢失来研究p300泛素连接酶活性在p53稳态中的特定作用。hHR 23 A和hHR 23 B蛋白酶体衔接蛋白的功能，以及hHR 23/MDM 2相互作用在p53调节中的作用，将通过在培养的细胞中和在重建的体外p53降解系统中的hHR 23蛋白的结构/功能分析来分析。一个新的，潜在的监管，hHR 23家族成员也将进一步表征其在DNA损伤调节p53稳定性的作用。