Structural basis for CBP/p300 transcriptional regulation

描述(申请人提供)：CREB结合蛋白(CBP)和p300是真核细胞中整合多种信号转导途径的通用转录调节因子，既是基因表达的辅助激活因子，也是基因表达的抑制因子。它们对细胞的生长、分化、凋亡和胚胎发育等基本功能是必不可少的。它们还发挥肿瘤抑制因子的作用，并调节控制细胞增殖、肿瘤发生和癌症进展的关键基因。由于其在关键细胞信号网络中的作用，CBP和p300是许多细胞和病毒癌蛋白的靶标。本提案的目的是阐明CBP和p300发挥其核心调控作用以防止或促进致癌转化的结构和分子基础。这项研究将集中在阐明CBP和p300与肿瘤抑制基因P53以及人乳头瘤病毒转化癌蛋白相互作用的分子决定因素。P53被复杂的磷酸化级联反应激活，导致P53转录激活结构域和CBP/p300之间的相互作用增强。高危型人乳头瘤病毒的E6和E7癌蛋白识别和结合CBP/p300，以抑制P53介导的转录途径，防止细胞凋亡，并转化宿主细胞。将利用最先进的结构、生物物理和蛋白质组学工具来阐明关键的CBP/p300相互作用的分子基础，这些相互作用负责激活P53对DNA损伤的反应，使宿主细胞永生化和被高风险的人乳头瘤病毒株转化，以及对损伤反应基因的调节和抑制。这项研究将为以下方面提供新的见解：响应遗传毒性应激激活P53调节基因的机制；高危人乳头瘤病毒癌蛋白通过分子相互作用颠覆细胞调节机制使细胞永生和转化；以及CBP作为转录抑制因子的功能。 与公共卫生相关：拟议的研究将解决CREB结合蛋白(CBP)和p300作为肿瘤抑制因子的机制，并调控控制细胞增殖、肿瘤形成和肿瘤进展的关键基因。这项研究将从分子水平上对CBP和p300在稳定和激活抑癌基因P53中的作用，以及在高危乳头状瘤病毒引起的人类细胞癌变中的作用提供新的分子水平的理解。它将提供关于CBP和p300预防或促进癌症的关键分子相互作用的新知识，这些相互作用是设计新型治疗剂的潜在目标。

DESCRIPTION (provided by applicant): CREB binding protein (CBP) and p300 are general transcriptional regulators that integrate numerous signal transduction pathways in eukaryotic cells, functioning both as coactivators and repressors of gene expression. They are essential for such basic cellular functions as growth, differentiation, apoptosis, and embryonic development. They also function as tumor suppressors and regulate key genes that control cellular proliferation, tumorigenesis, and cancer progression. Because of their function at the nexus of critical cell signaling networks, CBP and p300 are targeted by many cellular and viral oncoproteins. The goals of the present proposal are to elucidate the structural and molecular basis by which CBP and p300 perform their central regulatory roles to protect against or promote oncogenic transformation. The research will focus on elucidation of the molecular determinants by which CBP and p300 interact with the tumor suppressor p53 and with transforming oncoproteins from human papillomavirus. p53 is activated by a complex phosphorylation cascade that results in enhanced interactions between the p53 transcriptional activation domain and CBP/p300. The E6 and E7 oncoproteins from high risk human papillomavirus recognize and bind CBP/p300 to repress p53-mediated transcriptional pathways, prevent apoptosis, and transform the host cell. State-of-the-art structural, biophysical, and proteomics tools will be utilized to elucidate the molecular basis for key CBP/p300 interactions responsible for activation of the p53 response to DNA damage, immortalization and transformation of the host cell by high risk human papillomavirus strains, and regulation and repression of damage response genes. This research will provide novel insights into the mechanism of activation of p53-regulated genes in response to genotoxic stress, into the molecular interactions through which high risk human papillomavirus oncoproteins subvert the cellular regulatory machinery to immortalize and transform the cell, and into the function of CBP as a transcriptional repressor. PUBLIC HEALTH RELEVANCE: The proposed research will address the mechanisms by which CREB binding protein (CBP) and p300 function as tumor suppressors and regulate key genes that control cell proliferation, tumor formation, and tumor progression. This research will provide new molecular level understanding of the role of CBP and p300 in stabilization and activation of the tumor suppressor p53, and in the cancerous transformation of human cells by high risk papillomaviruses. It will provide new knowledge of the key molecular interactions by which CBP and p300 guard against or promote cancer, interactions which are of direct interest as potential targets for design of novel therapeutic agents.