TCR信号通路中负调控因子确保T细胞被恰当激活,维护T细胞自稳耐受及防止自身免疫性疾病发生.预研究表明静息T细胞中p38IP与激酶TAK1结合,TCR刺激下先解离再更强结合且抑制TAK1泛素化,推测p38IP经TAK1负调节TCR信号通路.将研究p38IP动态调节TAK1的具体机制,经质谱及western分析静息及刺激时p38IP及TAK1蛋白复合物组成,探究p38IP对TAK1与其结合蛋白TABs等结合的调节,寻找p38IP可能利用的去泛素化酶;靶定p38IP在静息及刺激时起抑制作用的功能域,比较p38IP及其抑制功能域对TCR诱导TAK1活性动态和T细胞活化的调节.制作T细胞条件性p38IP敲除小鼠,分析p38IP对T细胞发育包括Treg发育的调节;籍逆转录病毒载体及骨髓移植重建,比较p38IP及其抑制功能域对Treg发育的调节.诠释调节TCR信号通路及Treg发育的新机制.

The negative regulators in TCR signaling have a central role in appropriate activation of T cells, maintenance of T cell homeostasis, tolerance and prevention of autoimmune disease. Our preliminary data showed that p38IP associated with TAK1 in resting T cells, TCR stimulation induced a quick dissociation and then a stronger association between p38IP and TAK1. And p38IP inhibited TCR-induced TAK1 ubiquitiation and IL-2 production. Therefore, we propose that p38IP negatively regulates TCR signaling via targeting TAK1. We will study the detail mechanism underlying TCR-induced dynamical association between p38IP and TAK1. By using MS/MS and western blot analysis, we will analyze the proteins associate with p38IP and TAK1 before and after TCR stimulation, and try to find if there is a potential deubiquitinase involved in p38IP-mediated inhibition of TAK1 ubiquitiation. Then, we will check how p38IP regulates the association between TAK1 and its binding proteins TABs and the potential deubiquitinase. Next, we will map the domains on p38IP that are responsible for binding with TAK1 or inhibition of TAK1 ubiquitination before and after TCR stimulation, and analyze their role in regulation of TCR-induced TAK1 dynamical activation and T cell activation. Furthermore, we will make the T-cell-conditional p38IP-knockout mice and check T cell development. By the retroviral transduction of bone marrow and bone marrow transplantation and reconstitution, we will demonstrate the function and mechanism of p38IP in Treg development and maturation. Through this study, we hope to find a novel mechanism in regulation of TCR signaling and Treg cell development.