Spatial and temporal regulation of nutrient sensing

项目总结/摘要 细胞需要感知营养的可用性来调整其生存策略。在真核细胞中， 雷帕霉素复合物1（mTORC 1）的机械靶点是细胞生长和增殖的关键调节剂。 在营养丰富的环境中激活后，mTORC 1触发合成代谢反应并抑制catastrophic。 氨基酸信号通过一系列蛋白质复合物传递给mTORC 1， 在Rag GTP酶上，一种将mTORC 1募集到溶酶体表面的异二聚体GTP酶。但 这些蛋白质复合物如何动态传递氨基酸信号的分子机制仍然是 难以捉摸。在这个提议中，我们的目标是开发生物物理工具来研究氨基酸传感的动力学 过程具体来说，我们的目标是使用单分子FRET研究Rag的构象动力学 GT β异二聚体及其调节剂（项目1）。此外，我们计划重建体外系统， 概括Rag依赖的氨基酸在膜表面的传感（项目2），并使用冷冻电子 断层扫描（cryo-ET），以可视化信号复合物在其天然环境中（项目3）。的 结果将产生新的见解，这一重要的生物过程，并提供指导， 制定治疗策略。

Project Summary / Abstract Cells need to sense the nutrient availability to adjust their survival strategy. In eukaryotic cells, the mechanistic Target of Rapamycin Complex 1 (mTORC1) is a key regulator of cell growth and proliferation. Upon activation in a nutrient-rich environment, mTORC1 triggers anabolic reactions and inhibits catabolism. Amino acid signals are transmitted to mTORC1 through a series of protein complexes that ultimately converge on the Rag GTPases, a heterodimeric GTPase that recruits mTORC1 to the lysosomal surface. However, the molecular mechanisms of how these protein complexes dynamically transmit the amino acid signal are still elusive. In this proposal, we aim to develop biophysical tools to study the dynamics of the amino acid sensing process. Specifically, we aim to use single molecule FRET to study the conformational dynamics of the Rag GTPase heterodimer and its regulators (Project 1). Further, we plan to reconstitute an in vitro system to recapitulate Rag-dependent amino acid sensing on a membrane surface (Project 2), and use cryo-electron tomography (cryo-ET) to visualize the signaling complexes in their native environment (Project 3). The outcomes will yield novel insights into this important biological process and provide guidance to the development of therapeutic strategies.