Mitochondrial p32 regulation of the Mdm2-p53 tumor suppression signaling and apop

描述（由申请人提供）：我们实验室最近鉴定了一种位于大肠杆菌中的蛋白质p32，作为肿瘤抑制蛋白p14 ARF的结合伴侣。初步数据表明，p32是必不可少的p14 ARF，一个关键的介质转导过度增殖，致癌应激信号的Mdm 2-p53肿瘤抑制途径，定位到线粒体和诱导p53依赖性细胞凋亡。重要的是，人类癌症来源的p14 ARF突变破坏p32结合，可以损害这两种功能。最近，我们的初步研究表明，p32实际上是必不可少的细胞凋亡诱导的广泛的凋亡刺激。这项研究背后的总体假设是，p32为监测系统指定了一个重要因素，该系统监测线粒体功能的完整性，并促进细胞凋亡以应对不可修复的线粒体损伤。该假设的基本原理基于以下观察结果。(1)p32是一种线粒体蛋白。(2)敲低p32使细胞对由广泛的凋亡刺激诱导的凋亡脱敏。(3)与细胞色素c一样，p32在细胞凋亡过程中在细胞质中积累。(4)异位表达、胞浆定位的p32诱导细胞凋亡。(5)据报道p32在氧化磷酸化中起作用。本课题的实验重点是p32定位的动力学和结果、p32在调节细胞凋亡中的功能和机制、p32在代谢调节和肿瘤发生中的遗传学和生物学。基于这些观察结果，拟议的研究将集中在表征的功能和机制的p32在调节细胞凋亡的生物化学，细胞和遗传学的方法相结合。具体的目的是评估p32的作用，在广泛的凋亡条件下调节细胞凋亡，并确定p32的亚细胞定位的动力学，调查机制，p32促进凋亡细胞死亡，并调查p32的生理功能，使用p32条件性基因敲除小鼠。如果成功，拟议的研究将赋予p32新的功能。它还将有助于我们理解凋亡细胞死亡-这是一个在发展过程中至关重要的过程，并在疾病的发病机制，如癌症，类风湿性关节炎和神经退行性疾病-并可能最终导致额外的药物靶点控制细胞凋亡在治疗这些疾病。

DESCRIPTION (provided by applicant): A mitochondria-localized protein, p32, was recently identified by our lab as a binding partner for the tumor suppressor protein p14ARF. Preliminary data indicated that p32 is essential for p14ARF, a critical mediator for transducing hyperproliferative, oncogenic stress signals to the Mdm2-p53 tumor suppression pathway, to localize to mitochondria and to induce p53-dependent apoptosis. Importantly, human cancer-derived p14ARF mutations that disrupt p32 binding can impair both of these functions. Recently, our preliminary studies have shown that p32 is in fact essential for apoptosis induced by a broad range of apoptotic stimuli. The overall hypothesis behind the proposed research is that p32 specifies an essential factor for a surveillance system that monitors the integrity of mitochondrial function and promotes apoptosis in response to irreparable mitochondrial damage. The rationale for the hypothesis is based on the following observations. (1) p32 is a mitochondrial protein. (2) Knockdown p32 desensitizes cells to apoptosis induced by a broad range of apoptotic stimuli. (3) Like cytochrome c, p32 accumulates in the cytoplasm during apoptosis. (4) Ectopically expressed, cytoplasm- localized p32 induces apoptosis. (5) p32 is reported to have a role in oxidative phosphorylation. The experimental focus of the proposal is on dynamics and outcome of p32 localization, function and mechanism of p32 in regulating apoptosis, and genetics and biology of p32 in metabolic regulation and tumorigenesis. Based on these observations, the proposed research will focus on characterizing the function and mechanism of p32 in regulating apoptosis by a combination of biochemical, cellular, and genetic approaches. The specific aims are designed to assess p32's role in regulating apoptosis under a broad range of apoptotic conditions and define the dynamics of p32 subcellular localization, to Investigate mechanisms by which p32 promotes apoptotic cell death, and to investigate p32's physiological function using p32 conditional knockout mice. If successful, the proposed study will ascribe new functions to p32. It will also aid in our understanding of apoptotic cell death - a process that is critical during development and in the pathogenesis of diseases such as cancer, rheumatoid arthritis, and neurodegenerative diseases - and may eventually lead to additional drug targets for controlling apoptosis in treatment of these diseases.