Department of Pathology and Laboratory Medicine, David Geffen School of Medicine at University of California, Los Angeles, CA, United States of America.
Department of Chemistry and Biochemistry, University of California, Los Angeles, CA, United States of America.
Virology. 2014 Apr;454-455:118-27. doi: 10.1016/j.virol.2014.02.016. Epub 2014 Feb 28.
We previously identified HSP70 and HSC70 in complex with NS5A in a proteomic screen. Here, coimmunoprecipitation studies confirmed NS5A/HSC70 complex formation during infection, and immunofluorescence studies showed NS5A and HSC70 to colocalize. Unlike HSP70, HSC70 knockdown did not decrease viral protein levels. Rather, intracellular infectious virion assembly was significantly impaired by HSC70 knockdown. We also discovered that both HSC70 nucleotide binding and substrate binding domains directly bind NS5A whereas only the HSP70 nucleotide binding domain does. Knockdown of both HSC70 and HSP70 demonstrated an additive reduction in virus production. This data suggests that HSC70 and HSP70 play discrete roles in the viral life cycle. Investigation of these different functions may facilitate developing of novel strategies that target host proteins to treat HCV infection.
我们之前在蛋白质组学筛选中鉴定出 HSP70 和 HSC70 与 NS5A 形成复合物。在这里，共免疫沉淀研究证实了感染过程中 NS5A/HSC70 复合物的形成，免疫荧光研究显示 NS5A 和 HSC70 共定位。与 HSP70 不同，HSC70 的敲低并没有降低病毒蛋白水平。相反，HSC70 的敲低显著损害了细胞内传染性病毒颗粒的组装。我们还发现，HSC70 的核苷酸结合和底物结合结构域直接与 NS5A 结合，而只有 HSP70 的核苷酸结合结构域与 NS5A 结合。HSC70 和 HSP70 的敲低均导致病毒产量的显著降低。这些数据表明，HSC70 和 HSP70 在病毒生命周期中发挥不同的作用。对这些不同功能的研究可能有助于开发针对宿主蛋白治疗 HCV 感染的新策略。
