The Measles Virus V Protein Binding Site to STAT2 Overlaps That of IRF9
The Measles Virus V Protein Binding Site to STAT2 Overlaps That of IRF9
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麻疹病毒 V 蛋白与 STAT2 的结合位点与 IRF9 的结合位点重叠
DOI：
10.1128/jvi.01169-20
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发表时间：
2020
影响因子：
5.4
通讯作者：
Ose Toyoyuki
中科院分区：
文献类型：
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作者：
Nagano Yuma;Sugiyama Aoi;Kimoto Madoka;Wakahara Takuya;Noguchi Yasuyo;Jiang Xinxin;Saijo Shinya;Shimizu Nobutaka;Yabuno Nana;Yao Min;Gooley Paul R.;Moseley Gregory W.;Tadokoro Takashi;Maenaka Katsumi;Ose Toyoyuki
麻疹病毒（MeV）是一种高度免疫性和传染性的病原体，甚至可以减少已有的抗体，尽管有有效的疫苗，但它仍然是全世界儿童发病和死亡的主要原因。 MeV 是 JAK-STAT 拮抗机制方面研究最广泛的病毒之一。在从 MeVP 基因翻译的三种蛋白质中，P 和 V 对于该途径的失活至关重要。然而，缺乏对潜在相互作用的直接分析数据意味着拮抗作用的详细分子机制仍未解决。在这里，我们制备了负责人类 JAK-STAT 拮抗作用的重组 MeV V 蛋白和一组变体，从而能够对 V 蛋白进行生物物理表征，包括直接 V/STAT1 和 V/STAT2 相互作用测定。在没有 Jak1 或 Tyk2 等其他因子的情况下，观察到宿主和病毒因子之间明确的直接相互作用，并且首次对解离常数进行了量化。我们的数据表明，V 的 C 端区域和 STAT2 之间的相互作用比 V 的 N 端区域和 STAT1 之间的相互作用强 1 个数量级。我们还澄清，这些相互作用是完全独立的。此外，尺寸排阻色谱的结果表明，MeV-V的添加从预先形成的STAT2-核心/IRF相关结构域(IRF9)复合物中取代了STAT2-核心，即缺少N端和C端结构域的STAT2刚性区域。这些结果提供了一种新模型，MeV-V 不仅可以抑制 STAT2/IRF9 相互作用，还可以破坏预组装的干扰素刺激基因因子 3。 重要性 为了逃避宿主免疫，许多病原病毒使用不同的策略灭活宿主 Janus 激酶信号转导器和转录激活子 (STAT) 信号通路。麻疹病毒利用 P 和 V 蛋白来抵消这一信号通路。主要来自细胞测定的数据表明 P 和 V 蛋白的几个氨基酸残基同样重要。然而，V 蛋白的生物物理特性或其使用纯化蛋白与 STAT 分子的直接相互作用尚未被研究。我们开发了新的分子工具，使我们能够确定一种新的免疫逃避分子机制，V蛋白可以通过这种机制破坏关键的免疫复合物，从而为麻疹病毒抑制干扰素介导的抗病毒基因表达提供了明确的策略。
Measles virus (MeV) is a highly immunotropic and contagious pathogen that can even diminish preexisting antibodies and remains a major cause of childhood morbidity and mortality worldwide despite the availability of effective vaccines. MeV is one of the most extensively studied viruses with respect to the mechanisms of JAK-STAT antagonism. Of the three proteins translated from the MeVPgene, P and V are essential for inactivation of this pathway. However, the lack of data from direct analyses of the underlying interactions means that the detailed molecular mechanism of antagonism remains unresolved. Here, we prepared recombinant MeV V protein, which is responsible for human JAK-STAT antagonism, and a panel of variants, enabling the biophysical characterization of V protein, including direct V/STAT1 and V/STAT2 interaction assays. Unambiguous direct interactions between the host and viral factors, in the absence of other factors such as Jak1 or Tyk2, were observed, and the dissociation constants were quantified for the first time. Our data indicate that interactions between the C-terminal region of V and STAT2 is 1 order of magnitude stronger than that of the N-terminal region of V and STAT1. We also clarified that these interactions are completely independent of each other. Moreover, results of size exclusion chromatography demonstrated that addition of MeV-V displaces STAT2-core, a rigid region of STAT2 lacking the N- and C-terminal domains, from preformed complexes of STAT2-core/IRF-associated domain (IRF9). These results provide a novel model whereby MeV-V can not only inhibit the STAT2/IRF9 interaction but also disrupt preassembled interferon-stimulated gene factor 3.IMPORTANCETo evade host immunity, many pathogenic viruses inactivate host Janus kinase signal transducer and activator of transcription (STAT) signaling pathways using diverse strategies. Measles virus utilizes P and V proteins to counteract this signaling pathway. Data derived largely from cell-based assays have indicated several amino acid residues of P and V proteins as important. However, biophysical properties of V protein or its direct interaction with STAT molecules using purified proteins have not been studied. We have developed novel molecular tools enabling us to identify a novel molecular mechanism for immune evasion whereby V protein disrupts critical immune complexes, providing a clear strategy by which measles virus can suppress interferon-mediated antiviral gene expression.