Molecular Interactions and Regulation of p53

应激诱导的人抑癌基因P53的定点翻译后修饰 作为一种转录因子，P53在调节细胞周期停滞、衰老或 细胞凋亡。作为PPG的一部分，这个项目2的长期目标是寻求机械性的理解 P53在人类生物学和癌症中的分子相互作用和调控。而多重乙酰化 和P53的甲基化位点已有报道，单独或联合修饰对P53的特异性影响 P53的活性仍然难以捉摸。提供了初步数据，涉及基于结构的功能分析 P53支持乙酰化诱导P53激活以响应DNA损伤的概念 靶基因转录所需的辅激活子募集和随后的组蛋白乙酰化 激活。我们的研究明确支持P53共激活因子CBP(CREB)的招募 结合蛋白)需要在乙酰化的Lys[353]上将CBP溴域与P53结合：一种分子 P53诱导细胞周期蛋白依赖性激酶抑制因子转录激活所必需的相互作用 P21，参与(31)细胞周期停滞。因此，我们假设P53的不同修改包括 赖氨酸乙酰化和酰化对细胞内P53功能有不同的影响。我们提出了一个 用多方面的方法解决p53转录激活的机制基础 强调翻译后修饰在P53激活中的作用。具体目标是(1) 阐明这些修饰介导的P53与共激活剂分子相互作用的分子基础， 并开发基于结构设计的小分子化学探针来调节P53的功能 相互作用；以及(2)确定共激活子CBP/p300和p53 C-末端之间的相互作用 用多种生化和细胞方法研究p53转录调控和肿瘤抑制的结构域 生物学方法，包括建立体内模型。来自我们的新成果 计划中的研究预计将产生对翻译后修改的新的机械理解 P53功能。鉴于P53在癌症中的核心作用，这些研究将对 人类肿瘤的预后和治疗。

Site-specific post-translational modifications of human tumor suppressor p53 induced by stress play an important role in the activity of p53 as a transcription factor that regulates cell cycle arrest, senescence or apoptosis. The Iong-term goal of this Project 2, as a part of the PPG, is to seek mechanistic understanding of the molecular interactions and regulation of p53 in human biology and cancer. While multiple acetylation and methylation sites in p53 have been reported, specific effects of individual or combined modifications on p53 activity remain elusive. Preliminary data is presented involving a structure-based functional analysis of p53 supporting the notion that acetylation-induced p53 activation in response to DNA damage is involved in co-activator recruitment and subsequent histone acetylation required for target gene transcriptional activation. Our study specifically supports the notion that p53 recruitment of the co-activator CBP (CREB binding protein) requires association of the CBP bromodomain with p53 at acetylated lys[353]: a molecular interaction that is essential for p53-induced transcriptional activation of the cyclin-dependent kinase inhibitor p21, involved in (31 cell cycle arrest. We hypothesize therefore that distinct modifications of p53 including lysine acetylation and merhylation have differential effects on p53 functions in cells. We propose a multifaceted approach to address mechanistic underpinnings of p53 transcriptional activation with the emphasis on the role of post-translational modifications in p53 activation. The specific aims are (1) to elucidate molecular basis of these modification mediated molecular interactions of p53 with co-activators, and to develop small molecule chemical probes with structure-based design to functionally modulate p53 interactions; and (2) to determine the interplay between the co-activators CBP/p300 and p53 C-terminal domain in transcriptional regulation and tumor suppression of p53 using a variety of biochemical and cell biological approaches including the establishment of an in vivo model. The emerging results from our planned studies are expected to yield new mechanistic understanding of post-translational modifications in p53 function. Given the central role of p53 in cancer, these studies will have important implications for the prognosis and treatment of human tumors.