Phosphorylation of aryl hydrocarbon receptor interacting protein by TBK1 negatively regulates IRF7 and the type I interferon response.
Phosphorylation of aryl hydrocarbon receptor interacting protein by TBK1 negatively regulates IRF7 and the type I interferon response.
复制标题
DOI：
10.1016/j.jbc.2023.105525
复制
发表时间：
2024-01
影响因子：
4.8
通讯作者：
Harhaj, Edward W
中科院分区：
文献类型：
--
作者：
Kazzaz, Sarah A;Shaikh, Kashif A;White, Jesse;Zhou, Qinjie;Powell, Wade H;Harhaj, Edward W
对RNA病毒的先天性抗病毒反应起始于维甲酸诱导基因I（RIG-I）样受体对病毒RNA的识别，并引发I型干扰素（IFN）的产生。I型干扰素刺激干扰素刺激基因的表达，这些基因协同发挥抗病毒反应以防止全身感染。对I型干扰素及其主要调节因子——转录因子IRF7的负调控，对于维持免疫稳态至关重要。我们之前已证明，芳烃受体相互作用蛋白（AIP）通过与IRF7结合并将其隔离在细胞质中，发挥先天性抗病毒免疫反应负调节因子的作用，从而阻止IRF7的转录激活和I型干扰素的产生。然而，AIP对IRF7的抑制作用是如何受到调控的，目前仍不清楚。在此我们发现，激酶TBK1可使AIP发生磷酸化，苏氨酸40（Thr40）是TBK1磷酸化的主要靶点。AIP的Thr40在调节AIP稳定性以及介导其与IRF7的相互作用中发挥关键作用。与野生型AIP相比，模拟磷酸化的AIP（T40E）表现出蛋白酶体降解增加以及与IRF7的相互作用增强。AIP（T40E）还阻断了IRF7的核转位，导致I型干扰素产生减少和病毒复制增加。与此形成鲜明对比的是，AIP非磷酸化突变体（T40A）与IRF7的结合受损，在AIP缺陷型小鼠胚胎成纤维细胞中稳定表达AIP（T40A）可引发更强的I型干扰素反应，并减少RNA病毒复制。综上所述，这些结果表明，TBK1介导的AIP在Thr40位点的磷酸化起到分子开关的作用，使AIP能够与IRF7相互作用并抑制IRF7，从而防止IRF7过度激活I型干扰素基因。
The innate antiviral response to RNA viruses is initiated by sensing of viral RNAs by RIG-I-like receptors and elicits type I interferon (IFN) production, which stimulates the expression of IFN-stimulated genes that orchestrate the antiviral response to prevent systemic infection. Negative regulation of type I IFN and its master regulator, transcription factor IRF7, is essential to maintain immune homeostasis. We previously demonstrated that AIP (aryl hydrocarbon receptor interacting protein) functions as a negative regulator of the innate antiviral immune response by binding to and sequestering IRF7 in the cytoplasm, thereby preventing IRF7 transcriptional activation and type I IFN production. However, it remains unknown how AIP inhibition of IRF7 is regulated. We show here that the kinase TBK1 phosphorylates AIP and Thr40 serves as the primary target for TBK1 phosphorylation. AIP Thr40 plays critical roles in regulating AIP stability and mediating its interaction with IRF7. The AIP phosphomimetic T40E exhibited increased proteasomal degradation and enhanced interaction with IRF7 compared with wildtype AIP. AIP T40E also blocked IRF7 nuclear translocation, which resulted in reduced type I IFN production and increased viral replication. In sharp contrast, AIP phosphonull mutant T40A had impaired IRF7 binding, and stable expression of AIP T40A in AIP-deficient mouse embryonic fibroblasts elicited a heightened type I IFN response and diminished RNA virus replication. Taken together, these results demonstrate that TBK1-mediated phosphorylation of AIP at Thr40 functions as a molecular switch that enables AIP to interact with and inhibit IRF7, thus preventing overactivation of type I IFN genes by IRF7.