Identification of plasma membrane leucine receptor and elucidation of its link to mTOR signaling pathway

通过使用质谱学的比较定量蛋白质组学，确定了质膜亮氨酸受体的几个候选者。对这些候选蛋白的功能分析表明，有一个蛋白在生长因子受体下游的mTORC1途径中发挥作用，从而与氨基酸协同调节mTORC1的活性。针对整体膜蛋白检测和鉴定普遍困难的问题，通过改进样品制备工艺和质谱分析方法，建立了一种新的适用于膜整体蛋白的质谱分析方法。此外，为了揭示亮氨酸受体下游的整体信号事件，我们建立了一种定量磷酸蛋白质组学的方法。本研究为鉴定亮氨酸受体奠定了重要的技术基础。

By comparative quantitative proteomics using mass spectrometry, several candidates for the plasma membrane leucine receptor were identified. Functional analysis of these candidates revealed that one protein plays a role in mTORC1 pathway downstream of growth factor receptors and thereby regulates the activity of mTORC1 cooperatively with amino acids. We also developed a new analytical procedure of mass spectrometry suitable for integral membrane proteins by improving the sample preparation process and mass spectrometric measurement, because the detection and identification of integral membrane proteins were difficult in general. Additionally, to reveal the overall signaling events downstream of leucine receptor, we established a method for quantitative phosphoproteomics. The technical basis fundamentally important for the identification of leucine receptor has been established in this study.