FBXO2识别并调控糖基化c-Met蛋白在肿瘤发生与转移中的作用及其分子机制

FBXO2 is the substrate recognizing component of the SKP1-Cullin1-F-box (SCF) ubiquitin E3 ligase complexes, which recruiting and promoting glycosylated substrates for ubiquitin-mediated degradation to exhibit its biological function. Recently, by utilizing protein purification approach combined with LC−MS, we for the first time have systematically identified 528 glycoproteins that specially interacted with FBXO2. Furthermore, we have demonstrated the molecular mechanism of how FBXO2 recognizes and targets glycosylated insulin receptor (IR) for destruction. Moreover, we have also found that FBXO2 specifically interacts and regulates the protein level of glycosylated c-Met. Based on these original discoveries, this project will continue to investigate the following items: 1. to understand the molecular basis of the interaction between FBXO2 and glycosylated c-Met. 2. to demonstrate the molecular mechanism that how FBXO2 regulated the protein homeostasis of glycosylated c-Met. 3. To investigate the biological significances of FBXO2 in the regulation of glycosylated c-Met during the development and invasion stages of colon cancer. If funded, our project will not only help to identify the novel regulation mechanism of protein homeostasis of glycosylated c-Met, the novel biological function of FBXO2, but also critical to discover the pathology process of cancer with c-Met deregulation, and identify potential drug targets, which have critical scientific and social significances.

FBXO2是泛素蛋白连接酶复合物SCF的底物识别组分，通过募集并促进特异性糖基化底物蛋白的泛素化降解来发挥其生物学功能。最近，申请人采用蛋白质免疫沉淀结合液相质谱技术，首次系统性鉴定了528个FBXO2特异识别糖蛋白，阐明了FBXO2对糖基化胰岛素受体的识别与降解的分子机制。申请人还发现了FBXO2能特异性识别糖基化肝细胞生长因子受体(c-Met)并调控其蛋白水平。本项目将在这些重要的原创性发现的基础上，开展以下研究：(1)明确FBXO2和糖基化c-Met蛋白相互作用的分子基础。(2)阐明FBXO2对糖基化c-Met蛋白稳态调控的分子机制。(3)探讨FBXO2调控c-Met蛋白在肿癌发生以及转移过程中的生物学意义。本研究将不仅有益于发现调控c-Met蛋白稳态的新机制，探索FBXO2的新功能，对揭示以c-Met持续激活为诱因的肿瘤病理过程，乃至药物靶点的发现都有重要科学意义和社会意义。

F-box 蛋白是泛素 E3蛋白连接酶复合物 SCF中的底物识别组分，其家族成员能够通过蛋白-蛋白相互作用识别并募集底物，并促进其发生泛素化降解来发挥其生物学功能。F-box蛋白往往通过识别蛋白质的磷酸化或者糖基化修饰来结合并介导底物的降解。申请人发现F-box家族蛋白成员FBXO2和FBXO6通过分别识别并降解糖基化修饰的抑癌蛋白SUN2和RNASET2来促进肿瘤的进展。而其同家族成员FBXO16则通过泛素化降解hnRNPL来发挥其抑癌基因的作用。此外，申请人团队采用大规模定量磷酸化蛋白质组学技术，在国际上首次系统性鉴定了整个SCF家族的磷酸化底物蛋白，阐明了这些蛋白的磷酸化与泛素化修饰之间交叉对话的分子机制。通过大规模的蛋白质组学技术，申请人团队还建立了鉴定去泛素化酶底物的新技术和新方法，发现了USP14在糖脂代谢中的功能和机制。在国家自然科学基金委员会面上项目的资助支持下，申请人顺利完成了对F-box家族成员底物的鉴定和功能的探索，并以第一作者或通讯作者身份在Nature Communications, PNAS、Cell Death Differ、Cancer Letters以及Cell Death Dis等国际权威期刊上共发表高水平SCI文章13篇，累计影响因子超过100。