State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Science, Hunan Normal University, Changsha, 410081, China.
State Key Laboratory of Developmental Biology of Freshwater Fish, College of Life Science, Hunan Normal University, Changsha, 410081, China.
Fish Shellfish Immunol. 2019 Jun;89:736-744. doi: 10.1016/j.fsi.2019.04.040. Epub 2019 Apr 17.
TAK1-binding protein 1 (TAB1) forms the protein complex with TAK1 and enhances its kinase activity in human and mammals. To elucidate the role of TAB1 in the innate immunity of teleost sfih, the TAB1 homologue of black carp (Mylopharyngodon piceus) (bcTAB1) has been cloned and characterized in this paper. bcTAB1 is composed of 498 amino acids and contains a typical PP2Cc domain like its mammalian counterpart. The transcription of bcTAB1 gene in vivo and ex vivo varied in response to different stimuli; and the immunofluorescence staining showed that bcTAB1 was distributed in both cytoplasm and nucleus of host cell. The reporter assay showed that neither bcTAB1-expression alone nor co-expression of bcTAB1 and bcTAK1 could activate the transcription of IFN in EPC cells. Accordingly, EPC cells expressing bcTAB1 or co-expressing bcTAB1 and bcTAK1 showed no improved antiviral activity against grass carp reovirus (GCRV) and spring viremia of carp virus (SVCV). However, EPC cells co-expressing bcTAB1, bcTAK1 and bcIRF7 showed fiercely increased IFN-inducing ability in reporter assay and obviously improved antiviral activity in plaque assay compared with EPC cells co-expressing bcTAK1 and bcIRF7. The subsequent co-immunoprecipitation assay identified that bcTAB1 associated with bcTAK1 but not interacted with bcIRF7. Based on our previous finding that bcTAK1 up-regulates bcIRF7-mediated IFN signaling during host innate immune activation, the data generated in this study support the conclusion that bcTAB1 interacts with bcTAK1 and boosts bcTAK1-activated bcIRF7/IFN signaling during host antiviral innate immune response against GCRV and SVCV.
TAK1 结合蛋白 1（TAB1）在人和哺乳动物中与 TAK1 形成蛋白复合物，并增强其激酶活性。为了阐明 TAB1 在硬骨鱼类先天免疫中的作用，本文克隆并鉴定了草鱼（Mylopharyngodon piceus）的 TAB1 同源物（bcTAB1）。bcTAB1 由 498 个氨基酸组成，含有一个典型的 PP2Cc 结构域，与其哺乳动物对应物相似。体内和体外的 bcTAB1 基因转录对不同刺激有不同的反应；免疫荧光染色显示 bcTAB1 分布在宿主细胞的细胞质和细胞核中。报告基因检测表明，bcTAB1 表达本身或与 bcTAK1 共表达均不能激活 EPC 细胞中 IFN 的转录。因此，表达 bcTAB1 或共表达 bcTAB1 和 bcTAK1 的 EPC 细胞对草鱼呼肠孤病毒（GCRV）和鲤鱼出血病病毒（SVCV）均没有提高抗病毒活性。然而，共表达 bcTAB1、bcTAK1 和 bcIRF7 的 EPC 细胞在报告基因检测中表现出强烈增加的 IFN 诱导能力，并且在斑块测定中明显提高了抗病毒活性，与共表达 bcTAK1 和 bcIRF7 的 EPC 细胞相比。随后的免疫共沉淀检测表明，bcTAB1 与 bcTAK1 相关联，但不与 bcIRF7 相互作用。基于我们之前的发现，bcTAK1 在宿主先天免疫激活过程中上调 bcIRF7 介导的 IFN 信号，本研究的数据支持以下结论：bcTAB1 与 bcTAK1 相互作用，并在宿主抗病毒先天免疫反应中增强 bcTAK1 激活的 bcIRF7/IFN 信号，以抵抗 GCRV 和 SVCV。
