新的泛素修饰调控蛋白质UBXN1抑制NF-kB通路激活的功能及机制研究

The abnormal activation of NF-κB signaling pathway is closely related to a variety of pathological processes, such as inflammation and tumorigenesis. It is believed that ubiquitination modification is critical for the regulation of NF-κB activation. In our previous study, we demonstrated a key negative regulatory mechanism of NF-κB pathway and function in tumorigenesis (Nat Immunol 2008，Nat Med 2011, et al). We performed RNAi-based high-throughput screening recently and identified a new ubiquitination regulatory protein UBXN1 (UBX domain-containing protein 1). We further found that knockdown of UBXN1 promoted the activation of NF-κB pathway. Notably, immunohistochemistry analysis showed that the level of UBXN1 is significantly lower in a variety of tumors. Our prelimary data suggested that UBXN1 might play an important role in the regulation of NF-κB pathway and tumorigenesis. In this proposal, we will identify UBXN1 dynamic binding proteins in the regulation of NF-κB pathway by immunoaffinity purification and mass spectrometry analysis. Using gene silencing cell models and animal models, we will reveal the functions and mechanisms of UBXN1, an ubiquitination regulatory protein, in the activation of NF-κB signaling pathway with in vitro ubiquitination detection assay. Our study will shed light on the molecular mechanisms of the diseases related with the abnormalities of NF-κB pathway.

NF-κB信号通路的异常激活与炎症反应、肿瘤发生等多种病理过程密切相关，在此过程中泛素化修饰调控机制至关重要。我们前期研究发现了一个重要的NF-κB通路负向调节机制，并且与肿瘤发生相关（Nat Immunol 2008，共同通讯作者；Nat Med 2011等）。最近基于RNAi高通量筛选，我们鉴定了一个新的泛素化修饰调控蛋白UBXN1，沉默其基因表达能明显激活NF-κB通路，免疫组化显示UBXN1在多种肿瘤中显著低表达，提示UBXN1在调控NF-κB信号通路及肿瘤发生中可能发挥重要作用。在此基础上，本项目将通过免疫亲和纯化及质谱分析鉴定NF-κB通路中与UBXN1动态结合的蛋白质，利用已有的基因沉默细胞模型及动物模型，结合体外泛素化检测等手段，揭示泛素化修饰调控蛋白UBXN1在NF-κB信号通路中的功能及调控模式，为阐明NF-κB通路异常相关疾病的分子机制提供新线索。

NF-κB信号通路的异常激活与炎症反应、肿瘤发生等多种病理过程密切相关,在此过程中泛素化修饰调控机制至关重要。我们前期研究发现了一个重要的NF-κB通路负向调节机制,并且与肿瘤发生相关(Nat Immunol 2008,共同通讯作者;Nat Med 2011等）。基于RNAi高通量筛选，我们鉴定到一个新的泛素化修饰调控蛋白UBXN1，沉默其基因表达能明显激活NF-κB通路，揭示了泛素化修饰调控蛋白UBXN1在NF-κB信号通路中的功能及调控模式。此外，还研究了与NF-κB炎症信号通路相关的NLRP3炎症小体，并阐明NLRP3调节炎症小体的新机制。研究成果在Molecular Cell、EMBO Molecular Medicine、FEBS Letters等杂志发表研究论文6篇。培养硕士2人，项目负责人获得国家万人计划等多项奖励。该项目不仅圆满完成预定的科学目标，更重要的是发现了若干重要研究线索，为今后的深入探索打下了坚实基础。