Structural and Mechanistic Studies of the Mitochondrial Protein Folding Machinery

 描述（由申请人提供）：线粒体变性和功能障碍是衰老和衰老相关人类疾病的标志，包括阿尔茨海默病、帕金森病、亨廷顿病、癌症、2型糖尿病、动脉粥样硬化和心血管疾病。因此，线粒体已经进化出几种监视策略来保护细胞器免受损害。与此同时，靶向线粒体蛋白并选择性诱导细胞凋亡（例如癌细胞的细胞凋亡）的因子正在积极寻求。线粒体提供了一个范例来阐明分子伴侣和能量依赖性蛋白酶的网络，其协同作用以维持线粒体基质中的蛋白质稳态。人们广泛认识到，分子伴侣通过促进折叠和防止异常折叠和蛋白质聚集来提供针对蛋白质错误折叠疾病的第一道防线。除了它们在蛋白质折叠中的作用之外，线粒体伴侣蛋白，如Mortalin（mtHsp 70）和TRAP 1（mtHsp 90）也在大多数肿瘤细胞类型中广泛表达，包括结直肠癌、乳腺癌、前列腺癌和卵巢癌，这些肿瘤细胞具有最高的死亡率，但惊人的是不在高度增殖的非肿瘤细胞中。值得注意的是，TRAP 1的下调消除了骨肉瘤、结肠癌和宫颈癌细胞的转化潜力，支持了线粒体伴侣在癌细胞永生化中的新作用。因此，TRAP 1的抑制诱导前列腺癌细胞凋亡，强调线粒体伴侣作为有前途的新药物靶点的重要性。广泛和长期的研究目标是提供体外和体内线粒体蛋白质质量控制系统的分子理解，以确定正常和病理状态下线粒体蛋白质折叠机制的潜在合作机制和功能，以及如何使用小分子来调节线粒体伴侣功能。本研究的目标将通过以下具体目标来实现：1）表征正常和疾病状态下的线粒体蛋白质折叠机制; 2）用小分子化合物靶向TRAP 1的结构以调节其伴侣蛋白功能; 3）确定TRAP 1-底物相互作用的结构和分子基础。为了实现我们的研究目标，我们将使用多管齐下的体外和体内方法，该方法跨越不同的分辨率尺度，并增加了拟议研究的创新。

 DESCRIPTION (provided by applicant): Mitochondrial degeneration and dysfunction are a hallmark of aging and aging-related human diseases, including Alzheimer disease, Parkinson disease, Huntington disease, cancer, type 2 diabetes, atherosclerosis, and cardiovascular diseases. Consequently, mitochondria have evolved several surveillance strategies to protect the organelle from damage. At the same time, factors that target mitochondrial proteins and selectively induce apoptosis, for instance of cancer cells, are actively sought after. The mitochondria provide a paradigm to elucidate the network of molecular chaperones and energy-dependent proteases, which function synergistically to maintain protein homeostasis in the mitochondrial matrix. It is widely appreciated that molecular chaperones provide the first line of defense against protein misfolding diseases by promoting folding and preventing aberrant folding and protein aggregation. In addition to their role in protein folding, mitochondrial chaperones, such as Mortalin (mtHsp70) and TRAP1 (mtHsp90) are also widely expressed in most tumor cell types, including colorectal, breast, prostate, and ovarian cancer, which have the highest mortality rates, but strikingly not in highly proliferating, non-tumor cells. Remarkably, down- regulation of TRAP1 abrogates the transforming potential of osteosarcoma, colon carcinoma, and cervix carcinoma cells, supporting a new role of mitochondrial chaperones in the immortalization of cancer cells. Consistently, inhibition of TRAP1 induces apoptosis in prostate cancer cells, underscoring the significance of mitochondrial chaperones as promising new drug targets. The broad and long-term research objective is to provide a molecular understanding of the mitochondrial protein quality control system in vitro and in vivo, to determine the underlying cooperative mechanism and function of the mitochondrial protein folding machinery in normal and pathological states, and how small molecules can be used to modulate mitochondrial chaperone function. The goals of this research will be pursued through the following specific aims: 1) to characterize the mitochondrial protein folding machinery in normal and disease states; 2) to target the structure of TRAP1 with small molecule compounds to modulate its chaperone function; and 3) to determine the structural and molecular basis of TRAP1-substrate interaction. To accomplish our research objective, we will use a multi-pronged in vitro and in vivo approach, which spans different resolution scales and adds to the innovation of the proposed research.