砷新靶蛋白核仁素SUMO化修饰的发现及其作用机制的研究

项目名称： 砷新靶蛋白核仁素SUMO化修饰的发现及其作用机制的研究

项目编号： No.81472945

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 医药、卫生

项目作者： 张栋芸

作者单位： 温州医科大学

项目金额： 85万元

中文摘要： 砷化物是一类致癌但同时又可治癌的特殊化合物，但目前尚不能完全解释砷的这种双重生物学功能，故发现砷化物新靶点并阐述其作用机制是当前的研究热点。核仁素是一多功能核仁蛋白，具有传统原癌基因促增殖抑凋亡的作用。但我们研究发现，核仁素对砷暴露所致细胞凋亡有显著促进作用；核仁素能被SUMO修饰，且砷化物可促进该修饰作用。因此，我们推测核仁素及其SUMO修饰可能是介导砷化物双刃剑生物学功能的主要枢纽分子。本课题在进一步明确核仁素SUMO修饰位点的基础上，拟深入探讨砷暴露下核仁素及其SUMO修饰的功能及其分子机制。此项研究不仅有助于进一步了解砷化物的致癌机理、指导砷化合物在临床上安全有效的使用,而且将为合成和寻找高效且无或少副作用的砷衍生物提供理论依据和实验基础。

中文关键词： 环境毒理学；砷；核仁素；SUMO

英文摘要： Nucleolin is a ubiquitously expressed protein and participates in many important biological processes, such as cell cycle regulation and ribosomal biogenesis. The activity of nucleolin is regulated by intracellular localization and post-translational modifications(PTMs), including phosphorylation, methylation and ADP-ribosylation. Small ubiquitin-like modifier (SUMO) is a category of lately verified forms of PTMs, and exerts various effects on the target proteins. Our preliminary studies clearly indicated that nucleolin was subjected to SUMOylational modification. More importantly, we found arsenite treatment for 24 h could obviously increase nucleolin SUMOylation. This entrigerred us to explore the promising nucleolin SUMOylation site by various molecular methods, including site-directed point mutagenesis, Western Blotting assay, and Ni2+-beads pulldown. Furthermore, we will check whether nucleolin-SUMO would affect arsenite-induced cell apoptosis and cell transfomration using both in vitro and in vivo methods. In addition, we aim to investigate the underlying molecular mechasims for the role of nucleollin-SUMO in arsenite-associated cellular functions. Collectively, our findings here not only discovered a new modification of nucleolin protein and its novel functional paradigm in mRNA biogenesis processes, but also expanded our understanding regarding the dichotomous roles of arsenite in term of cancer development dependent on multiple intracellular conditions, such as oxidative stress vs. pro-proliferative signals, which made appropriate regulations of protein modifications, including SUMOylation.

英文关键词： environmental carcinogen;arsenite;nucleolin;SUMOylation