hFIST/HIPK2在Fas/FasL和TNF/TNFR1介导的凋亡信号转导途径中的作用

Role of serine/threonine protein kinase hFIST/HIPK2 in signal transduction pathway in Fas/FasL-and TNF/TNFR1-mediated apoptosis

目的 探讨hFIST/HIPK2在Fas/FasL介导的凋亡信号转导途经中的作用。方法 应用瞬时转染技术 ,将全长序列hFIST/HIPK2、Fas(CD95 /Apo 1)、TNFR1、FADD、TRADD、caspase 8cDNAs转染入 2 93T细胞中 ,应用免疫沉淀技术、WesternBlotting技术检测hFIST/HIPK2与以上凋亡相关蛋白的相互作用。结果 hFIST/HIPK2与Fas、TNFR1、FADD、caspase 8无相互作用 ,与TRADD有相互作用 ,且Fas、TNFR1竞争性抑制这种相互作用。在有FasL存在及无FasL存在时 ,Fas均可与FADD相互作用 ;Fas与TRADD有相互作用。结论 hFIST/HIPK2与TRADD有相互作用 ,Fas与TRADD有相互作用 ,hFIST/HIPK2可能间接参与了Fas/FasL。

Objective To investigate the mechanisms in the regulation of Fas/FasL signal transduction pathway and to find more new Fas associated proteins by means of investigating the roles of hFIST/HIPK2 (human Fas interacting signal transducer/homeodomain interacting protein kinase) in this pathway. Methods Full length hFIST/HIPK2, Fas (CD95/Apo 1), TNFR1, FADD, TRADD, and Caspase 8 cDNAs were transfected into human kidney embryonic cell line 293T cells by transient transfection. The interaction of Fas with these apoptosis associated proteins was analyzed by immunoprecipitation and Western blotting. Results hFIST/HIPK2 interacted with TRADD, but not with TNFR1, FADD nor Caspase 8. Apo 1 and TNFR1 competitively inhibited the interaction of hFIST/HIPK2 with TRADD. Fas interacted with FADD both in the presence of and in the absence of FasL. Fas could interact with TRADD. Conclusion hFIST/HIPK2 may interact with TRADD and Fas with TRADD, suggesting that hFIST/HIPK2 may play an indirect role in the signal transduction pathway in Fas/FasL and TNF/TNFR1 mediated apoptosis.