溶酶体蛋白LAPTM4B通过与Xc-系统相互作用调控谷胱甘肽代谢的机制研究

谷胱甘肽具有调控氧化应激的重要生理功能，其代谢主要发生于细胞膜、线粒体和细胞质内，最新研究报道谷胱甘肽在溶酶体内也有分布，但其代谢调控不详。我们前期工作通过代谢组学策略发现溶酶体蛋白LAPTM4B可特异性调控谷胱甘肽代谢；同时，我们也发现LAPTM4B与谷胱甘肽合成限速元件Xc-系统相互作用于溶酶体，提示LAPTM4B可能通过与Xc-系统蛋白互作，调控其亚细胞定位和氨基酸转运，从而介导谷胱甘肽代谢和细胞氧化应激。本项目拟：（1）确认LAPTM4B是否通过蛋白互作招募并稳定Xc-系统于溶酶体，调控Xc-系统的氨基酸转运能力；（2）探究LAPTM4B调控谷胱甘肽代谢的生理意义；（3）明确LAPTM4B抑制药物是否可精确调节谷胱甘肽代谢。我们的工作将深入解析LAPTM4B调控谷胱甘肽代谢的分子机制，丰富对溶酶体参与谷胱甘肽代谢途径的认知，并初步探讨小分子抑制药物的潜在应用价值。

Glutathione displays vital roles in oxidative stress, its metabolism research focuses on the plasma membrane, mitochondrial, and cytoplasm, however, it is unclear how it metabolizes in lysosomes, even though lysosome functions as the hub of cell metabolism. In this project, we have discovered the lysosomal protein LAPTM4B regulating glutathione metabolism from a metabonomics analysis; meanwhile by utilizing proteomics screening, immunoprecipitation and microscopy, we have identified that LAPTM4B interacts with Xc- system (the key component in glutathione metabolism) on lysosome. We further hypothesized “LAPTM4B regulates the subcellular localization and amino acid transporting capability of Xc- system by protein-protein interaction, thus affecting cellular glutathione metabolism and oxidative stress”. In this project, we focus on the molecular mechanism of LAPTM4B regulating glutathione metabolism, mainly studying: (1) The subcellular distribution and transportation ability of Xc- system; (2) Whether LAPTM4B mediated glutathione metabolism further affect cellular oxidative stress; (3) The effect of LAPTM4B inhibitors on glutathione metabolism. This project will resolve the molecular mechanism of LAPTM4B regulation in glutathione metabolism, enrich the knowledge of lysosome function in glutathione metabolism, and explore the potential usage of LAPTM4B inhibitors.