p53 Stabilization and Neurodegeneration

描述（改编自申请人的摘要）：本项目的长期目标 项目是确定导致肿瘤抑制因子 p53 的分子机制 中枢神经系统中的积累和神经元变性。的 应用程序基于进行研究时获得的新发现 与我们之前的 NIH 申请相关。 p53 通路的激活 与哺乳动物中枢神经细胞凋亡密切相关 系统。在非神经细胞中，p53 丰度受到严格控制 涉及 Mdm2 癌蛋白的抑制反馈环，该蛋白结合并 靶向 p53 进行泛素介导的降解。然而，事件的责任 神经元 DNA 损伤后 p53 的稳定性尚未被描述。 我们的初步研究证明了 p53 积累的新机制 下调泛素以及 p53 蛋白在 凋亡神经元的核仁。因此，拟议的研究将使用 分子和生化方法来研究 p53 的假设 稳定性是某些类型神经元的重要组成部分 变性部分是由核仁功能受损介导的。具体 目标 1 将确定 Mdm2 结合是否调节 p53 功能，并将 在动物和细胞培养模型中采用不同的方法来确定 p53 积累是否对于神经元细胞死亡至关重要。具体目标2 将研究 p53 是否调节泛素-蛋白酶体系统。 具体目标 3 将描述 p53 对核仁功能的影响 神经元变性。最后，具体目标 4 将确定神经元是否 通过恢复脆弱神经元的 p53 降解来防止死亡。这些 研究应该会显着增加我们对分子基础的理解 某些类型的神经元细胞死亡以及新分子和新分子的开发 神经退行性疾病的药物干预。

DESCRIPTION (Adapted from applicant's abstract): The long-term goal of this project is to define the molecular mechanisms leading to tumor suppressor p53 accumulation and neuronal degeneration in the central nervous system. The application is based on novel findings obtained while conducting studies related to our previous NIH application. Activation of the p53 pathway has been strongly implicated in neuronal apoptosis in the mammalian central nervous system. In non-neural cells p53 abundance is tightly controlled by an inhibitory feedback loop involving the Mdm2 oncoprotein which binds to and targets p53 for ubiquitin-mediated degradation. However, the events responsible for p53 stabilization following DNA damage in neurons have not been delineated. Our preliminary studies demonstrate a novel mechanism of p53 accumulation due to down regulation of ubiquitin, as well as localization of p53 protein in the nucleolus of apoptotic neurons. The proposed studies will therefore use molecular and biochemical approaches to investigate the hypothesis that p53 stabilization is an essential component of certain types of neuronal degeneration mediated, in part, by impairment of nucleolar function. Specific Aim 1 will determine whether Mdm2 binding modulates p53 function, and will employ different approaches in animal and cell culture models to determine whether p53 accumulation is essential for neuronal cell death. Specific Aim 2 will investigate whether p53 regulates the ubiquitin-proteasome system. Specific Aim 3 will characterize the effect of p53 on nucleolar function in neuronal degeneration. Finally, Specific Aim 4 will determine whether neuronal death is prevented by restoring p53 degradation to vulnerable neurons. These studies should significantly add to our understanding of the molecular basis of certain types of neuronal cell death and the development of novel molecular and pharmacological interventions for neurodegenerative diseases.