Cell Growth Signaling in Cancer Development

项目摘要 mTOR通路是一种信号传导系统，其响应于细胞凋亡而调节生长和代谢。 生物体的营养状态。越来越多的证据表明，该途径通常是放松管制， 癌症、神经系统疾病和糖尿病，并且还调节衰老过程。mTOR蛋白 激酶是药物雷帕霉素的靶标和两种多蛋白复合物的催化亚基， mTOR复合物1（mTORC 1）和2（mTORC 2），使通路的不同分支成核， 响应不同的上游信号。mTORC 1对各种刺激有反应，包括不同类型的刺激。 生长因子，营养素和压力，并调节许多合成代谢和分解代谢过程， 分别包括蛋白质、核苷酸和脂质合成以及自噬。最近，我们发现 mTORC 1部分通过溶酶体感知营养物质，并确定了一个多通道溶酶体， 膜蛋白，SLC 38 A9，这是传感氨基酸精氨酸的关键。SLC 38 A9原来是 比我们最初预期的要有趣得多，因为它不仅向mTORC 1发出信号， 主要作用是将必需氨基酸从溶酶体中排出，使其可用于细胞溶质， 流程.此外，使用我们开发的一种新方法来分析 我们惊奇地发现mTORC 1本身是一个主要的调节因子， 来自溶酶体的大多数非极性必需氨基酸。因此，mTORC 1既位于下游， 上游的溶酶体功能，表明它是一个电路的一部分，调节和感觉 溶酶体响应生长信号发挥功能。我们工作的总体目标是， 了解溶酶体如何向mTORC 1发出信号，以及mTORC 1如何 调节溶酶体功能。此外，我们发现我们正在研究的机制是 对于胰腺癌细胞的增殖特别重要，因此我们打算测试它们的作用， 在小鼠胰腺肿瘤的发展中起着重要作用。 我们提出的工作的具体目标是：了解溶酶体膜蛋白如何 SLC 38 A9控制mTORC 1信号传导（目标1）;测试SLC 38 A9在发展中的重要性。 胰腺肿瘤（目标2）;并了解mTORC 1如何控制溶酶体氨基酸的流出 (Aim 3）。我们将通过多学科方法实现这些目标， 生物化学、分子生物学和小鼠工程。我们的成果将大大提高我们的 了解临床重要的mTORC 1通路，并测试SLC 38 A9是否是一种潜在的药物 胰腺癌的靶点。

Project Summary The mTOR pathway is a signaling system that regulates growth and metabolism in response to the nutritional state of organisms. Increasing evidence shows that the pathway is commonly deregulated in cancer, neurological disorders, and diabetes, and also modulates the aging process. The mTOR protein kinase is the target of the drug rapamycin and the catalytic subunit of two multi-protein complexes, mTOR Complex 1 (mTORC1) and 2 (mTORC2), that nucleate distinct branches of the pathway and respond to different upstream signals. mTORC1 responds to a variety of stimuli, including diverse types of growth factors, nutrients, and stresses, and regulates many anabolic and catabolic processes, including protein, nucleotide, and lipid synthesis and autophagy, respectively. Recently, we discovered that mTORC1 senses nutrients in part through the lysosome and identified a multi-pass lysosomal membrane protein, SLC38A9, that is key for sensing the amino acid arginine. SLC38A9 turns out to be much more interesting than we originally anticipated as not only does it signal to mTORC1 it also has a major role in effluxing an essential amino acid out of the lysosome so it can be used in cytosolic processes. In addition, using a new method we developed to profile the metabolite contents of lysosomes, we made the surprising discovering that mTORC1 itself is a major regulator of the efflux of most non-polar essential amino acids from lysosomes. Thus, mTORC1 is both downstream and upstream of lysosomal function, indicating that it is part of a circuit that modulates and senses lysosome function in response to growth signals. The broad goals of our work are to arrive at a mechanistic understanding of how the lysosome signals to mTORC1 and in turn how mTORC1 regulates lysosome function. In addition, we have found that the mechanisms we are studying are particularly important for the proliferation of pancreatic cancer cells and so we intend to test their roles in the development of pancreatic tumors in mice. The specific aims of our proposed work are to: understand how the lysosomal membrane protein SLC38A9 controls mTORC1 signaling (Aim 1); test the importance of SLC38A9 in the development of pancreatic tumors (Aim 2); and understand how mTORC1 controls the efflux of lysosomal amino acids (Aim 3). We will accomplish these goals with a multi-disciplinary approach that uses the tools of biochemistry, molecular biology, and mouse engineering. Our results will substantially increase our understanding of the clinically important mTORC1 pathway and test if SLC38A9 is a potential drug target in pancreatic cancer.