Guo Min, Pei Rongjuan, Yang Qi, Cao Huang, Wang Yun, Wu Chunchen, Chen Jizheng, Zhou Yuan, Hu Xue, Lu Mengji, Chen Xinwen
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China University of Chinese Academy of Sciences, Beijing, China.
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
J Virol. 2015 Feb;89(4):2367-77. doi: 10.1128/JVI.02982-14. Epub 2014 Dec 10.
Several members of the phospholipase family have been reported to be involved in hepatitis C virus (HCV) replication. Here, we identified another phospholipase, phosphatidylserine-specific phospholipase A1 (PLA1A), as a host factor involved in HCV assembly. PLA1A was upregulated by HCV infection, and PLA1A knockdown significantly reduced J399EM (genotype 2a) HCV propagation at the assembly step but not the entry, RNA replication, and protein translation steps of the life cycle. Protein localization and interaction analysis further revealed a role of PLA1A in the interaction of NS2-E2 and NS2-NS5A, as the formation of the NS2-E2 and NS2-NS5A complexes was weakened in the absence of PLA1A. In addition, PLA1A stabilized the NS2/NS5A dotted structure during infection. These data suggest that PLA1A plays an important role in bridging the membrane-associated NS2-E2 complex and the NS5A-associated replication complex via its interaction with E2, NS2, and NS5A, which leads to a coordinating interaction between the structural and nonstructural proteins and facilitates viral assembly.
Hepatitis C virus (HCV) genomic replication is driven by the replication complex and occurs at the membranous web, while the lipid droplet is the organelle in which virion assembly is initiated. In this study, we identified phosphatidylserine-specific phospholipase A1 (PLA1A), a member of phospholipase A 1 family, as a novel host factor involved in the assembly process of HCV. PLA1A, which is induced by HCV infection at a late infection stage, interacts with HCV E2, NS2, and NS5A proteins and enhances and stabilizes the NS2-E2 and NS2-NS5A complex formation, which is essential for viral assembly. Thus, PLA1A is an important host factor which is involved in the initiation of the viral assembly in close proximity to Core-decorated lipid droplets through bringing together the HCV replication complex and envelope complex.
据报道，磷脂酶家族的几个成员参与丙型肝炎病毒（HCV）复制。在此，我们鉴定出另一种磷脂酶，磷脂酰丝氨酸特异性磷脂酶A1（PLA1A），作为参与HCV组装的宿主因子。HCV感染可上调PLA1A，敲低PLA1A可在组装步骤显著降低J399EM（2a基因型）HCV的增殖，但不影响生命周期的进入、RNA复制和蛋白质翻译步骤。蛋白质定位和相互作用分析进一步揭示了PLA1A在NS2-E2和NS2-NS5A相互作用中的作用，因为在没有PLA1A的情况下，NS2-E2和NS2-NS5A复合物的形成会减弱。此外，PLA1A在感染期间稳定了NS2/NS5A点状结构。这些数据表明，PLA1A通过与E2、NS2和NS5A相互作用，在连接膜相关的NS2-E2复合物和NS5A相关的复制复合物中发挥重要作用，这导致结构蛋白和非结构蛋白之间的协同相互作用并促进病毒组装。
丙型肝炎病毒（HCV）基因组复制由复制复合物驱动并发生在膜网，而脂滴是启动病毒体组装的细胞器。在本研究中，我们鉴定出磷脂酶A1家族成员磷脂酰丝氨酸特异性磷脂酶A1（PLA1A）作为参与HCV组装过程的新型宿主因子。PLA1A在感染后期由HCV感染诱导，与HCV E2、NS2和NS5A蛋白相互作用，增强并稳定NS2-E2和NS2-NS5A复合物的形成，这对病毒组装至关重要。因此，PLA1A是一个重要的宿主因子，通过将HCV复制复合物和包膜复合物聚集在一起，参与在靠近核心修饰脂滴处启动病毒组装。
