Regulation by mTORC1 of the lysosomal efflux of essential amino acids

项目摘要/摘要 雷帕霉素复合体1的作用靶点是一种丝氨酸/苏氨酸激酶，它 通过平衡合成代谢和分解代谢过程来协调细胞生长和代谢 营养、生长因子信号和能量水平1，2。这一途径中的信号失控 与许多人类疾病有关，包括神经退行性变、糖尿病和癌症。因此， 参与mTORC1激活及其调控的生物过程的机制是 浓厚的兴趣。 溶酶体在mTORC1营养传感分支的信号转导中起着至关重要的作用 路径9.在开发一种用于快速分离纯溶酶体的新工具时，我们做出了令人惊讶的 发现mTORC1调节一组不同的非极性的溶酶体浓度，主要是必需的 氨基酸。用同样的方法，我们注意到SLC38A9的缺失，这是一种很大程度上未被研究的氨基酸 感受溶酶体精氨酸的转运体，导致同一组非极性的，主要是 必需氨基酸。尽管如此，mTORC1调节溶酶体的机制 通过SLC38A9的必需氨基酸的丰度尚不清楚。对这一机制的阐明将给出 对哺乳动物细胞如何响应营养供应的关键见解，也可能提供新的治疗方法 治疗肿瘤的靶点。 初步证据表明，RAG-Ragator复合体与SLC38A9相互作用，并传递 为了调节必需氨基酸的外流，mTORC1需要营养物质的供应 溶酶体中的酸。MTORC1调控SLC38A9的分子机制研究 关于交通功能，我们提出了以下目标： 。 1.确定mTORC1在控制SLC38A9与RAG-1相互作用中的作用 刺客。 2.了解Rag-Ragator磷酸化在运输调节中的作用 SLC38A9功能。 3.鉴定调节SLC38A9的溶酶体蛋白。

Project Summary/Abstract The mechanistic target of rapamycin complex 1 (mTORC1) is a serine/threonine kinase which coordinates cell growth and metabolism by balancing anabolic and catabolic processes in response to nutrients, growth factor signaling, and energy levels 1,2. Deregulated signaling in this pathway has been implicated in many human diseases including neurodegeneration, diabetes, and cancer3. As such, the mechanisms involved in mTORC1 activation and the biological processes under the control of mTORC1 are of significant interest. Lysosomes play a crucial role in the signal transduction of the nutrient sensing branch of the mTORC1 pathway9. While developing a novel tool for the rapid isolation of pure lysosomes, we made the surprising discovery that mTORC1 regulates the lysosomal concentration of a distinct set of non-polar, mostly essential amino acids. Using the same method, we noticed that loss of SLC38A9, a largely unstudied amino acid transporter that senses lysosomal arginine, results in the accumulation of the same set of non-polar, mostly essential amino acids. Despite this knowledge, the mechanism by which mTORC1 regulates the lysosomal abundance of essential amino acids through SLC38A9 is not known. Elucidation of this mechanism will give key insights into how mammalian cells respond to nutrient availability and may also provide novel therapeutic targets for the treatment of tumors. Preliminary evidence suggests the Rag-Ragulator complex, which interacts with SLC38A9 and conveys the availability of nutrients to mTORC1, is necessary for mTORC1 to regulate the efflux of essential amino acids from lysosomes. To characterize the molecular mechanism by which mTORC1 regulates SLC38A9 transport function, we propose the following aims: . 1. Determine the role of mTORC1 in controlling the interaction between SLC38A9 and Rag- Ragulator. 2. Understand the role of Rag-Ragulator phosphorylation on the regulation of the transport function of SLC38A9. 3. Identification of lysosomal proteins that regulate SLC38A9.