P53 AND UV REGULATION OF P53 BINDING PROTEIN BBP/53BP2

描述（申请人描述）： 肿瘤抑制基因p53是 在超过50%的人类癌症中发生突变，并在 介导对遗传毒性应激的细胞反应。 因此有 对我们理解癌症至关重要的是研究复杂的通路， p53相互作用蛋白质。 Bbp/53 BP 2蛋白与野生型p53结合， p53-Bbp/53 BP 2复合物的晶体结构揭示了Bbp/53 BP 2结合 p53上的一个位点由进化上保守的区域组成，这些区域在p53中经常突变。 癌 Bbp/53 BP 2还在体外与细胞凋亡调节因子相互作用。 蛋白Bcl-2，增强p53介导的转录激活，并阻碍 循环进展。 然而，调控Bbp/53 BP 2的机制 表达是未知的。 候选人已经发现野生型（但不是 突变体）p53可抑制Bbp/53 BP 2蛋白表达，但Bbp/53 BP 2 蛋白质在UV照射后被诱导。 因此，野生型p53是一个关键， Bbp/53 BP 2的结合伴侣的调节，并且这种调节被调节 紫外线引起的DNA损伤这个项目的长期目标是了解 Bbp/53 BP 2的功能与癌症的关系 的目的 我们的建议是确定Bbp/53 BP 2表达是如何调节的，以及这种调节是如何进行的。 影响细胞生理学这一提议的核心假设是， 与野生型p53复合的Bbp/53 BP 2蛋白在未应激细胞中降解 但在紫外线损伤的细胞中没有，导致Bbp/53 BP 2的上调 蛋白质对紫外线辐射的响应。拟议研究的理由 一旦调控Bbp/53 BP 2表达的机制被了解， 其与p53和Bcl-2相互作用的体内结果可以是 研究了 我们将通过以下三个具体目标来检验这一假设：1）。 确定野生型p53如何下调Bbp/53 BP 2表达，2）。确定 紫外线照射如何上调Bbp/53 BP 2表达，以及3）。确定 Bbp/53 BP 2表达在细胞对紫外线照射的反应中的作用。的 这项工作是创新的，因为它利用了Bbp/53 BP 2和p53 诱导细胞系，以研究它们相互作用的功能后果 无论是否存在细胞损伤预计这一 方法将确定p53依赖性和紫外线损伤诱导机制 控制Bbp/53 BP 2。这一点很重要，因为了解Bbp/53 BP 2 受p53调控，紫外线照射将定义新的调控途径 参与细胞对DNA损伤的反应。拟议的培训计划 是在一个充满活力的研究环境与广泛的知识和技术 支持. 因此，候选人将获得技能，以确保教师 学术肿瘤学的职位。

DESCRIPTION (Applicant's Description): The tumor suppressor p53 gene is mutated in over 50 percent of human cancers and plays a pivotal role in mediating the cellular responses to genotoxic stress. Therefore, it is critical to our understanding of cancer to study the complex pathways defined by p53-interacting proteins. Bbp/53BP2 protein binds to wild-type p53; the crystal structure of the p53-Bbp/53BP2 complex reveals the Bbp/53BP2 binding site on p53 consists of evolutionarily conserved regions frequently mutated in cancer. Bbp/53BP2 also interacts in vitro with the apoptosis regulating protein Bcl-2, enhances p53-mediated transcriptional activation, and impedes c e l l cycle progression. However, the mechanisms regulating Bbp/53BP2 expression are unknown. The candidate has found that wild-type (but not mutant) p53 can suppress Bbp/53BP2 protein expression, but that Bbp/53BP2 protein is induced following UV-irradiation. Thus, wild-type p53 is a key regulator of its binding partner Bbp/53BP2, and this regulation is modulated by UV-induced DNA-damage. The long-range goal of this project is to understand how the function of Bbp/53BP2 relates to cancer. The objective of this proposal is to determine how Bbp/53BP2 expression is regulated and how this affects cellular physiology. The central hypothesis of this proposal is that Bbp/53BP2 protein complexed to wild-type p53 is degraded in unstressed cells but not in UV-damaged cells, resulting in the upregulation of Bbp/53BP2 protein in response to UV-irradiation. The rationale for the proposed research is that once the mechanisms regulating Bbp/53BP2 expression are known, then the in vivo consequences of its interactions with p53 and Bcl-2 can be studied. The hypothesis will be tested by pursuing three specific aims: 1). Determine how wild-type p53 downregulates Bbp/53BP2 expression, 2). Determine how UV-irradiation upregulates Bbp/53BP2 expression, and 3). Determine the role of Bbp/53BP2 expression in the cellular response to UV-irradiation. The proposed work is innovative because it capitalizes on Bbp/53BP2 and p53 inducible cell lines to study the functional consequences of their interaction in the presence or absence of cellular damage. It is expected that this approach will identify p53-dependent and UV-damage inducible mechanisms controlling Bbp/53BP2. This is significant because understanding how Bbp/53BP2 is modulated by p53 and UV- irradiation will define new regulatory pathways involved in the cellular response to DNA-damage. The proposed training program is in a dynamic research environment with extensive intellectual and technical support. Thus, the candidate will acquire the skills to secure a faculty position in academic medical oncology.