PLP2 of mouse hepatitis virus A59 (MHV-A59) targets TBK1 to negatively regulate cellular type I interferon signaling pathway.
PLP2 of mouse hepatitis virus A59 (MHV-A59) targets TBK1 to negatively regulate cellular type I interferon signaling pathway.
复制标题
小鼠肝炎病毒 A59 (MHV-A59) 的 PLP2 靶向 TBK1 负调控细胞 I 型干扰素信号通路
DOI：
10.1371/journal.pone.0017192
复制
发表时间：
2011-02-18
期刊：
影响因子：
3.7
通讯作者：
Tang H
中科院分区：
文献类型：
--
作者：
Wang G;Chen G;Zheng D;Cheng G;Tang H
背景 严重急性呼吸综合征 (SARS) 冠状病毒 (SCoV) 和小鼠肝炎病毒 A59 (MHV-A59) 等冠状病毒已经进化出策略来禁用先天免疫系统，从而使感染有效复制和传播。我们之前已经证明，木瓜蛋白酶结构域 2 (PLP2) 是 MHV-A59 非结构蛋白 3 (nsp3) 的催化结构域，编码去泛素酶 (DUB) 并失活 IFN 调节因子 3 (IRF3)，从而使 I 型干扰素 (IFN) 反应失活。主要发现在这里，我们提供了进一步的证据，表明 PLP2 还可能靶向 TANK 结合激酶 1 (TBK1)，即 IFN 信号通路中 IRF3 的上游激酶。过表达实验表明，PLP2 使 TBK1 去泛素化并降低其激酶活性，从而抑制 IFN-β 报告基因活性。尽管PLP2在去泛素化细胞蛋白方面混杂，但在TNF受体相关因子3（TRAF3）缺陷的细胞中，PLP2使TBK1和IFN-β反应失活，这表明靶向TBK1足以让PLP2抑制IRF3激活。这一观点得到了体外激酶测定的进一步支持，其中先前用 PLP2 处理 TBK1 抑制了其磷酸化 IRF3 的激酶活性。有趣的是，PLP2过表达系统和MHV-A59感染系统的结果证明，PLP2在细胞质中与TBK1和IRF3形成无活性的复合物，并且PLP2的存在以剂量依赖的方式稳定了低磷酸化的IRF3-TBK1复合物。结论这些结果表明PLP2不仅使TBK1失活，而且还阻止IRF3核转位，从而抑制IFN转录激活。鉴定 PLP2 在抑制 IFN 信号传导中保守的 DUB 活性将为开发抗冠状病毒感染的疗法提供有用的线索。
Background Coronaviruses such as severe acute respiratory syndrome (SARS) coronavirus (SCoV) and mouse hepatitis virus A59 (MHV-A59) have evolved strategies to disable the innate immune system for productive replication and spread of infection. We have previously shown that papain-like protease domain 2 (PLP2), a catalytic domain of the nonstructural protein 3 (nsp3) of MHV-A59, encodes a deubiquitinase (DUB) and inactivates IFN regulatory factor 3 (IRF3) thereby the type I interferon (IFN) response. Principal Findings Here we provide further evidence that PLP2 may also target TANK-binding kinase-1 (TBK1), the upstream kinase of IRF3 in the IFN signaling pathway. Overexpression experiments showed that PLP2 deubiquitinated TBK1 and reduced its kinase activity, hence inhibited IFN-β reporter activity. Albeit promiscuous in deubiquitinating cellular proteins, PLP2 inactivated TBK1 and IFN-β response in TNF receptor associated factor 3 (TRAF3) deficient cells, suggesting that targeting TBK1 would be sufficient for PLP2 to inhibit IRF3 activation. This notion was further supported by in vitro kinase assays, in which prior treatment of TBK1 with PLP2 inhibited its kinase activity to phosphorylate IRF3. Intriguing enough, results of PLP2 overexpression system and MHV-A59 infection system proved that PLP2 formed an inactive complex with TBK1 and IRF3 in the cytoplasm and the presence of PLP2 stabilized the hypo-phosphorylated IRF3-TBK1 complex in a dose-dependent manner. Conclusions These results suggest that PLP2 not only inactivates TBK1, but also prevents IRF3 nuclear translocation hence inhibits IFN transcription activation. Identification of the conserved DUB activity of PLP2 in suppression of IFN signaling would provide a useful clue to the development of therapeutics against coronaviruses infection.
登录
查看更多内容
冠状病毒类木瓜蛋白酶的去泛素化和干扰素拮抗活性
影响因子：
5.4
作者：
Clementz, Mark A.;Chen, Zhongbin;Baker, Susan C.
通讯作者：
Baker, Susan C.
影响因子：
3.9
作者：
Higgs, Rowan;Jefferies, Caroline A.
通讯作者：
Jefferies, Caroline A.
影响因子：
5.4
作者：
Kuo, LL;Masters, PS
通讯作者：
Masters, PS
DOI：
10.1126/science.1183021
发表时间：
2010-01-15
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Iwasaki A;Medzhitov R
通讯作者：
Medzhitov R
影响因子：
5
作者：
Frieman, Matthew;Heise, Mark;Baric, Ralph
通讯作者：
Baric, Ralph