School of Life Science, Key Lab of Aquatic Resources and Utilization of Jiangxi Province, Nanchang University, Nanchang, 330031, China.
School of Life Science, Key Lab of Aquatic Resources and Utilization of Jiangxi Province, Nanchang University, Nanchang, 330031, China.
Fish Shellfish Immunol. 2024 Jul;150:109647. doi: 10.1016/j.fsi.2024.109647. Epub 2024 May 24.
NIK (NF-κB inducing kinase) belongs to the mitogen-activated protein kinase family, which activates NF-κB and plays a vital role in immunology, inflammation, apoptosis, and a series of pathological responses. In NF-κB noncanonical pathway, NIK and IKKα have been often studied in mammals and zebrafish. However, few have explored the relationship between NIK and other subunits of the IKK complex. As a classic kinase in the NF-κB canonical pathway, IKKβ has never been researched with NIK in fish. In this paper, the full-length cDNA sequence of grass carp (Ctenopharyngodon idella) NIK (CiNIK) was first cloned and identified. The expression level of CiNIK in grass carp cells was increased under GCRV stimuli. Under the stimulation of GCRV, poly (I:C), and LPS, the expression of NIK in various tissues of grass carp was also increased. This suggests that CiNIK responds to viral stimuli. To study the relationship between CiNIK and CiIKKβ, we co-transfected CiNIK-FLAG and CiIKKB-GFP into grass carp cells in coimmunoprecipitation and immunofluorescence experiments. The results revealed that CiNIK interacts with CiIKKβ. Besides, the degree of autophosphorylation of CiNIK was enhanced under poly (I:C) stimulation. CiIKKβ was phosphorylated by CiNIK and then activated the activity of p65. The activity change of p65 indicates that NF-κB downstream inflammatory genes will be functioning. CiNIK or CiIKKβ up-regulated the expression of IL-8. It got higher when CiNIK and CiIKKβ coexisted. This paper revealed that NF-κB canonical pathway and noncanonical pathway are not completely separated in generating benefits.
NIK（NF-κB 诱导激酶）属于丝裂原活化蛋白激酶家族，可激活 NF-κB，在免疫学、炎症、细胞凋亡和一系列病理反应中发挥重要作用。在 NF-κB 非经典途径中，在哺乳动物和斑马鱼中经常研究 NIK 和 IKKα。然而，很少有研究探索 NIK 与 IKK 复合物的其他亚基之间的关系。作为 NF-κB 经典途径中的一种经典激酶，在鱼类中，从未对 IKKβ与 NIK 进行过研究。在本文中，首次克隆并鉴定了草鱼（Ctenopharyngodon idella）NIK（CiNIK）的全长 cDNA 序列。在 GCRV 刺激下，草鱼细胞中 CiNIK 的表达水平增加。在 GCRV、poly（I:C）和 LPS 的刺激下，草鱼各组织中 NIK 的表达也增加。这表明 CiNIK 对病毒刺激有反应。为了研究 CiNIK 与 CiIKKβ 之间的关系，我们在共转染 CiNIK-FLAG 和 CiIKKB-GFP 到草鱼细胞中进行了 co-immunoprecipitation 和免疫荧光实验。结果表明 CiNIK 与 CiIKKβ 相互作用。此外，在 poly（I:C）刺激下 CiNIK 的自磷酸化程度增强。CiIKKβ 被 CiNIK 磷酸化，然后激活 p65 的活性。p65 的活性变化表明 NF-κB 下游炎症基因将发挥作用。CiNIK 或 CiIKKβ 上调了 IL-8 的表达。当 CiNIK 和 CiIKKβ 共存时，其表达水平更高。本文揭示了 NF-κB 经典途径和非经典途径在产生益处时并非完全分离。
