Akt Contributes to Activation of the TRIF-Dependent Signaling Pathways of TLRs by Interacting with TANK-Binding Kinase 1
Akt Contributes to Activation of the TRIF-Dependent Signaling Pathways of TLRs by Interacting with TANK-Binding Kinase 1
复制标题
DOI：
10.4049/jimmunol.0903534
复制
发表时间：
2011-01-01
影响因子：
4.4
通讯作者：
Lee, Joo Young
中科院分区：
文献类型：
--
作者：
Joung, Sun Myung;Park, Zee-Yong;Lee, Joo Young
含有Toll/IL-1 R结构域的衔接子诱导IFN-β（TRIF）是一种衔接子分子，其在激动剂刺激后被募集至TLR 3和TLR-4，并触发IFN调节因子3（IRF 3）的活化和1型IFN的表达，这对于细胞抗病毒应答至关重要。我们发现Akt是TRIF/TANK结合激酶1（TBK 1）的下游分子，并且在TLR 3和TLR 4激动剂激活IRF 3中起重要作用。通过显性失活突变体或短干扰RNA阻断Akt可降低由聚肌苷酸：聚胞苷酸[poly（I：C）]、LPS、TRIF和TBK 1诱导的IRF 3活化和IFN-β表达。当用poly（I：C）和LPS刺激时，在巨噬细胞中观察到内源性TBK 1和Akt的关联。体外激酶测定结合反相液相色谱质谱分析表明，TBK 1增强了Ser（473）上Akt的磷酸化，而巨噬细胞中短干扰RNA敲低TBK 1表达则降低了poly（I：C）和LPS诱导的Akt磷酸化。来自TBK 1敲除小鼠的胚胎成纤维细胞也显示出对poly（I：C）和LPS的响应的Akt磷酸化受损。据我们所知，我们的研究结果证明了一个新的调节机制Akt激活介导的TBK 1和一个新的作用Akt在TLR介导的免疫反应。免疫学杂志，2011，186：499-507。
Toll/IL-1R domain-containing adaptor inducing IFN-beta (TRIF) is an adaptor molecule that is recruited to TLR3 and -4 upon agonist stimulation and triggers activation of IFN regulatory factor 3 (IRF3) and expression of type 1 IFNs, which are critical for cellular antiviral responses. We show that Akt is a downstream molecule of TRIF/TANK-binding kinase 1 (TBK1) and plays an important role in the activation of IRF3 by TLR3 and -4 agonists. Blockade of Akt by a dominant-negative mutant or by short interfering RNA decreased IRF3 activation and IFN-beta expression induced by polyinosinic: polycytidylic acid [poly(I: C)], LPS, TRIF, and TBK1. Association of endogenous TBK1 and Akt was observed in macrophages when stimulated with poly(I: C) and LPS. In vitro kinase assays combined with reversed-phase liquid chromatography mass spectrometry analysis showed that TBK1 enhanced phosphorylation of Akt on Ser(473), whereas knockdown of TBK1 expression by short interfering RNA in macrophages decreased poly(I: C)and LPS-induced Akt phosphorylation. Embryonic fibroblasts derived from TBK1 knockout mice also showed impaired Akt phosphorylation in response to poly(I: C) and LPS. To our knowledge, our results demonstrate a new regulatory mechanism for Akt activation mediated by TBK1 and a novel role of Akt in TLR-mediated immune responses. The Journal of Immunology, 2011, 186: 499-507.