RacGTPase-activating protein 1 interacts with hepatitis C virus polymerase NS5B to regulate viral replication
RacGTPase-activating protein 1 interacts with hepatitis C virus polymerase NS5B to regulate viral replication
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DOI：
10.1016/j.bbrc.2014.10.008
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发表时间：
2014-11-07
影响因子：
3.1
通讯作者：
Horng, Jim-Tong
中科院分区：
文献类型：
--
作者：
Wu, Ming-Jhan;Ke, Po-Yuan;Horng, Jim-Tong
丙型肝炎病毒 (HCV) 是一种正链 RNA 病毒，可导致慢性肝病和肝细胞癌 (HCC)。 RacGTP 酶激活蛋白 1 (RacGAP1) 在 Rac1 和 CDC42 蛋白中的 GTP 水解为 GDP 的过程中发挥着重要作用，并已被证明在包括 HCC 在内的多种癌症中表达上调。然而，导致 RacGAP1 上调的分子机制仍知之甚少。在这里，我们发现 RacGAP1 水平在 HCV 细胞培养源 (HCVcc) 感染中增强。更重要的是，我们证明了 RacGAP1 与哺乳动物细胞中的病毒蛋白 NS5B 相互作用。在人肝癌细胞系中，小干扰 RNA (siRNA) 介导的 RacGAP1 敲低可抑制 HCV RNA、蛋白质的复制以及 HCV 基因型 2a 株 JFH1 感染性颗粒的产生。相反，这些结果可以通过表达 siRNA 抗性 RacGAP1 重组蛋白来逆转。此外，在基于细胞的报告基因检测中，通过沉默 RacGAP1，病毒蛋白 NS5B 聚合酶活性显着降低，反之亦然，通过过度表达 RacGAP1，病毒蛋白 NS5B 聚合酶活性增加。我们的结果表明，RacGAP1 通过影响病毒蛋白 NS5B 聚合酶活性在 HCV 复制中发挥着至关重要的作用，并且对于抗病毒药物的开发具有重要意义。 (C) 2014 Elsevier Inc. 保留所有权利。
Hepatitis C virus (HCV) is a positive-strand RNA virus responsible for chronic liver disease and hepatocellular carcinoma (HCC). RacGTPase-activating protein 1 (RacGAP1) plays an important role during GTP hydrolysis to GDP in Rac1 and CDC42 protein and has been demonstrated to be upregulated in several cancers, including HCC. However, the molecular mechanism leading to the upregulation of RacGAP1 remains poorly understood. Here, we showed that RacGAP1 levels were enhanced in HCV cell-culturederived (HCVcc) infection. More importantly, we illustrated that RacGAP1 interacts with the viral protein NS5B in mammalian cells. The small interfering RNA (siRNA)-mediated knockdown of RacGAP1 in human hepatoma cell lines inhibited replication of HCV RNA, protein, and production of infectious particles of HCV genotype 2a strain JFH1. Conversely, these were reversed by the expression of a siRNA-resistant RacGAP1 recombinant protein. In addition, viral protein NS5B polymerase activity was significantly reduced by silencing RacGAP1 and, vice versa, was increased by overexpression of RacGAP1 in a cell-based reporter assay. Our results suggest that RacGAP1 plays a crucial role in HCV replication by affecting viral protein NS5B polymerase activity and holds importance for antiviral drug development. (C) 2014 Elsevier Inc. All rights reserved.