Phosphorylation Status of Tyrosine 78 Residue Regulates the Nuclear Export and Ubiquitination of Influenza A Virus Nucleoprotein
Phosphorylation Status of Tyrosine 78 Residue Regulates the Nuclear Export and Ubiquitination of Influenza A Virus Nucleoprotein
复制标题
酪氨酸78残基的磷酸化状态调节甲型流感病毒核蛋白的核输出和泛素化
DOI：
10.3389/fmicb.2019.01816
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发表时间：
2019-08-07
影响因子：
5.2
通讯作者：
Liu, Wenjun
中科院分区：
文献类型：
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作者：
Cui, Liang;Zheng, Weinan;Liu, Wenjun
核蛋白（NP）的磷酸化和去磷酸化在甲型流感病毒（IAV）的生命周期中发挥着重要作用，并且NP上各个磷酸化位点在控制病毒复制方面的生物学功能并不完全相同。在这里，我们通过质谱鉴定了 NP 的酪氨酸 78 残基 (Y78) 作为一个新的磷酸化位点。 Y78 高度保守，Y78E 模仿的恒定 NP 磷酸化通过减少 NP 与细胞输出受体 CRM1 的结合来延迟 NP 核输出，并损害病毒生长。此外，酪氨酸激酶抑制剂达沙替尼和AG490降低了Y78磷酸化并加速了NP核输出，这表明Janus和Src激酶催化的Y78磷酸化在病毒复制过程中调节NP核输出。更重要的是，我们发现NP磷酸化可以通过减弱NP与E3泛素连接酶TRIM22之间的相互作用来抑制NP泛素化，这证明了NP磷酸化和泛素化之间的串扰。这项研究表明，Y78 的磷酸化状态通过抑制 NP 的核输出和泛素化来调节 IAV 复制。总体而言，这些发现为 NP 磷酸化的生物学作用，特别是其在 NP 泛素化中的负面作用提供了新的线索。
Phosphorylation and dephosphorylation of nucleoprotein (NP) play significant roles in the life cycle of influenza A virus (IAV), and the biological functions of each phosphorylation site on NP are not exactly the same in controlling viral replication. Here, we identified tyrosine 78 residue (Y78) of NP as a novel phosphorylation site by mass spectrometry. Y78 is highly conserved, and the constant NP phosphorylation mimicked by Y78E delayed NP nuclear export through reducing the binding of NP to the cellular export receptor CRM1, and impaired virus growth. Furthermore, the tyrosine kinase inhibitors Dasatinib and AG490 reduced Y78 phosphorylation and accelerated NP nuclear export, suggesting that the Janus and Src kinases-catalyzed Y78 phosphorylation regulated NP nuclear export during viral replication. More importantly, we found that the NP phosphorylation could suppress NP ubiquitination via weakening the interaction between NP and E3 ubiquitin ligase TRIM22, which demonstrated a cross-talk between the phosphorylation and ubiquitination of NP. This study suggests that the phosphorylation status of Y78 regulates IAV replication by inhibiting the nuclear export and ubiquitination of NP. Overall, these findings shed new light on the biological roles of NP phosphorylation, especially its negative role in NP ubiquitination.