Supplementary Material for: Ste20-Like Kinase TAOK1 Positively Regulates Antiviral Responses by Controlling the TBK1-IRF3 Signaling Axis

The cytosolic viral nucleic acid-sensing pathways converge on the protein kinase TANK-binding kinase 1 (TBK1) and the transcription factor interferon (IFN)-regulatory factor 3 (IRF3) to induce type I IFN production and antiviral immune responses. However, the mechanism that triggers the binding of TBK1 and IRF3 after virus infection remains not fully understood. Here, we identified that thousand and one kinase 1 (TAOK1), a Ste20-like kinase, positively regulated virus-induced antiviral immune responses by controlling the TBK1-IRF3 signaling axis. Virus invasion downregulated the expression of TAOK1. TAOK1 deficiency resulted in decreased nucleic acid-mediated type I IFN production and increased susceptibility to virus infection. TAOK1 was constitutively associated with TBK1 independently of the mitochondrial antiviral signaling protein MAVS. TAOK1 promoted IRF3 activation by enhancing TBK1-IRF3 complex formation. TAOK1 enhanced virus-induced type I IFN production in a kinase activity-dependent manner. Viral infection induced TAOK1 to bind with dynein instead of microtubule-associated protein 4 (MAP4), leading to the trafficking of TBK1 to the perinuclear region to bind IRF3. Thus, the depolymerization of microtubule impaired virus-mediated IRF3 activation. Our results revealed that TAOK1 functioned as a new interaction partner and regulated antiviral signaling via trafficking TBK1 along microtubules to bind IRF3. These findings provided novel insights into the function of TAOK1 in the antiviral innate immune response and its related clinical significance.

胞质病毒核酸感知通路汇聚于蛋白激酶TANK结合激酶1（TANK-binding kinase 1, TBK1）和转录因子干扰素（interferon, IFN）调节因子3（IRF3），以诱导I型干扰素产生及抗病毒免疫应答。然而，病毒感染后触发TBK1与IRF3结合的分子机制仍未完全阐明。本研究鉴定出Ste20样激酶千和一激酶1（thousand and one kinase 1, TAOK1）可通过调控TBK1-IRF3信号轴，正向调控病毒诱导的抗病毒免疫应答。病毒入侵会下调TAOK1的表达。TAOK1缺失会导致核酸介导的I型干扰素产生减少，并增加机体对病毒感染的易感性。TAOK1可不依赖于线粒体抗病毒信号蛋白MAVS（mitochondrial antiviral signaling protein, MAVS）与TBK1组成性结合。TAOK1通过增强TBK1-IRF3复合物的形成，促进IRF3的活化。TAOK1以激酶活性依赖的方式增强病毒诱导的I型干扰素产生。病毒感染会诱导TAOK1与动力蛋白结合，而非微管相关蛋白4（microtubule-associated protein 4, MAP4），从而介导TBK1向核周区域转运以结合IRF3。因此，微管解聚会损伤病毒介导的IRF3活化。本研究结果揭示TAOK1是一种新型互作伴侣蛋白，可通过沿微管转运TBK1使其结合IRF3，从而调控抗病毒信号通路。这些发现为TAOK1在抗病毒天然免疫应答中的功能及其相关临床意义提供了全新的见解。