构架蛋白TRAF对CD154诱导转录因子NF-κB活化的影响

TRAF proteins in CD154-induced NF-κB activation

目的 研究构架蛋白TRAF1-6在CD154诱导NF-κB活化信号通路中的作用机制。方法 通过流式细胞仪分析TRAF蛋白在RamosB细胞中的基础表达，转染野生型或显性失活TRAF判断TRAF对NF-κB活化的影响，并研究CD154刺激可诱导哪些TRAF蛋白与CD40免疫共沉淀。结果 TRAF1、2、3、5和TRAF6在Ramos B细胞中均有基础表达，转染野生型TRAF6较其他TRAF可更显著诱导NF-κB活化，而转染显性失活质粒对CD154诱导NF-κB活化的抑制作用TRAF6〉TRAF5〉TRAF2〉TRAF3。CD154刺激诱导TRAF2、6与CD40共沉淀。结论 TRAF6在CD154诱导NF-κB活化中作用最重要；CD154刺激诱导TRAF2、6与CD40形成免疫复合物。

Objective To investigate the role of TRAF in CD154-induced NF-κB activation. Methods Ramos B cells were assessed for cytoplasmic expression of TRAF by FACS analysis. Cells were also transiently transfected with vector expressing wild-type or dominant-negative（DN） versions of TRAF to analyse their effects in CD154-induced NF-κB activation. Immunoprecipitation experiments were performed using anti-CD40 conjugated protein-A beads to examine TRAF＇s association with CD40. Results TRAF 1,2,3,5 and TRAF6 are constitutively expressed in Ramos B cells; Overexpression of TRAF6 induces NF-κB activation; The inhibition effects of DNTRAFs on CD40 induced NF-κB activity are as DNTRAF6 〉 5 〉 2 〉 3 ; TRAF2 and 6 coimmunoprecipitate with CD40 when stimulated with CD154. Conclusion TRAF6 is the most important TRAF in CD154-induced NF-κB activation in Ramos B cells. CD154 stimulation induces ARAF2 and 6 associations with CD40.