Structural and Mechanistic Studies of the Mitochondrial Protein Folding Machinery

 描述(申请人提供)：线粒体退化和功能障碍是衰老和与衰老相关的人类疾病的标志，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，线粒体演变了几种监视策略来保护细胞器免受损害。与此同时，以线粒体蛋白为靶点并选择性地诱导细胞凋亡的因子，例如癌细胞，正受到积极追捧。线粒体提供了一个范例来阐明分子伴侣和能量依赖的蛋白酶网络，它们协同作用维持线粒体基质中的蛋白质动态平衡。人们普遍认识到，分子伴侣通过促进折叠，防止异常折叠和蛋白质聚集，为蛋白质错误折叠疾病提供了第一道防线。除了在蛋白质折叠中的作用外，线粒体伴侣蛋白，如Mortalin(MtHsp70)和TRAP1(MtHsp90)也广泛表达于大多数肿瘤细胞类型，包括结直肠癌、乳腺癌、前列腺癌和卵巢癌，这些肿瘤细胞的死亡率最高，但令人惊讶的是，在高增殖的非肿瘤细胞中不表达。值得注意的是，TRAP1的下调取消了骨肉瘤、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。一直以来，抑制TRAP1诱导前列腺癌细胞凋亡，强调了线粒体伴侣作为有希望的新药靶点的重要性。其广泛和长期的研究目标是提供对体外和体内线粒体蛋白质质量控制系统的分子理解，确定线粒体蛋白质折叠机制在正常和病理状态下的潜在合作机制和功能，以及如何利用小分子来调节线粒体伴侣功能。本研究的目标包括：1)研究正常和疾病状态下线粒体蛋白质折叠机制；2)利用小分子化合物靶向TRAP1的结构以调节其伴侣功能；3)确定TRAP1-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，我们将使用体外和体内多管齐下的方法，这种方法跨越不同的分辨率尺度，增加了拟议研究的创新性。

 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.