细胞程序性坏死关键蛋白RIPK1/RIPK3泛素化调控机制的研究

Necroptosis is a non-apoptotic form of cell death morphologically resembling necrosis but executes in a regulated approach. Necroptosis has been revealed to contribute to a variety of pathological consequences, including ischemia-reperfusion injury, stroke, inflammatory bowel diseases, viral infection, neurodegenerative diseases and cancers. The kinase inhibitors of RIPK1, which play essential role in necroptosis, are currently being tested in Phase I and Phase II clinical trials for Alzherimer’s Diseases, Amyotrophic Lateral Sclerosis, Psoriasis, Rheumatoid Arthritis, Inflammatory Bowel Diseases, etc.. The mechanistic study of necroptosis in the past decade has been focused in the RIPK1/RIPK3 kinase and their substrates’ phosphorylation. More and more evidence suggests that ubiquitination is involved in the process of necroptosis as well. However the underlying mechanism is not fully understood yet. This project is proposed to characterize the sites and types of RIPK1/RIPK3 ubiquitination triggered during necroptosis and to identify E3 ligases and deubiquitinases mediating RIPK1/RIPK3 ubiquitination. Furthermore, we’ll investigate the functional significance of RIPK1/RIPK3 ubiquitination in necroptotic signaling, and the coordination between ubiquitination and phosphorylation. It’ll provide promising pathologic biomarkers or novel therapeutic targets for necroptosis-related diseases.

细胞程序性坏死是近些年细胞死亡领域的研究热点之一，与多种疾病密切相关。其中的关键调控因子RIPK1为神经退行性疾病、银屑病、类风湿性关节炎、溃疡性结肠炎等提供了一个非常有前景的治疗靶点，相应的激酶抑制剂正应用于相关疾病的临床试验中。以往关于程序性坏死的机制研究主要集中在RIPK1/RIPK3的激酶活性及磷酸化调控中，然而，越来越多的证据表明细胞程序性坏死的信号通路网络交错复杂，仍有许多重要的节点及调控机制有待发现。泛素化调控也广泛地参与了TNFα介导的细胞程序性坏死过程。本项目拟从泛素化入手，研究程序性坏死过程中关键蛋白RIPK1/RIPK3的泛素化位点及参与调控的泛素连接酶和去泛素化酶，并理解不同刺激下细胞泛素化状态的变化及其与磷酸化之间的相互影响。该项研究不仅有利于丰富程序性坏死的信号通路，并为相关的生理病理过程提供合理的调控机制和药物靶点。

细胞程序性坏死是近些年细胞死亡领域的研究热点之一，与多种疾病密切相关，其中的关键调控因子为相关疾病提供了非常有前景的治疗靶点。以往关于程序性坏死的机制研究主要集中在RIPK1/RIPK3的激酶活性及磷酸化调控中，然而越来越多的证据表明细胞程序性坏死的信号通路网络交错复杂，仍有许多重要的节点及调控机制有待发现，泛素化调控也广泛地参与了TNFα介导的细胞程序性坏死过程。本项目从泛素化入手，研究程序性坏死过程中关键蛋白的泛素化位点及参与调控的泛素连接酶和去泛素化酶，发现CUL3-KCTD12-RBX1泛素连接酶复合物和OTUB1去泛素化酶分别通过调控RIPK3 K282/K364位和K302位泛素化，促进了RIPK3的激酶活性，从而介导细胞程序性坏死的发生。该项研究表明RIPK3的泛素化状态的变化可以调控其磷酸化水平，不仅有利于丰富程序性坏死的信号通路，并为相关的生理病理过程提供合理的调控机制和药物靶点。