Activation of the N-Ras-PI3K-Akt-mTOR pathway by hepatitis C virus:: Control of cell survival and viral replication
Activation of the N-Ras-PI3K-Akt-mTOR pathway by hepatitis C virus:: Control of cell survival and viral replication
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DOI：
10.1128/jvi.79.14.8742-8749.2005
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发表时间：
2005-07-01
影响因子：
5.4
通讯作者：
Beretta, L
中科院分区：
文献类型：
--
作者：
Mannová, P;Beretta, L
丙型肝炎病毒（HCV）复制复合体位于耐洗涤剂膜或脂筏内。我们分析了从表达自我复制全长HCV-1b基因组的Huh 7细胞中分离的耐洗涤剂组分的蛋白质含量。使用二维凝胶电泳，然后通过质谱，我们确定了N-Ras作为其中的表达增加的蛋白质之一，从HCV基因组复制子克隆的洗涤剂抗性馏分相比，控制细胞。N-Ras是磷脂酰肌醇-3-激酶（PI 3 K）-Akt途径的激活剂。我们发现，在HCV复制细胞中，PI 3 K和Akt的活性以及它们的下游靶点mTOR的活性增加。PI 3 K-Akt-和mTOR-依赖性途径均显示促进细胞存活。与此一致，HCV复制子细胞对血清饥饿诱导的细胞凋亡具有抗性。我们还描述了该途径在HCV复制中的作用。通过转染N-Ras小干扰RNA（siRNA）减少N-Ras表达导致HCV复制增加。我们在用PI 3 K抑制剂LY 294002处理的细胞和用mTOR siRNA转染的细胞中观察到HCV复制的类似增加。综上所述，这些数据表明，增加的N-Ras水平在亚细胞位点的HCV复制和刺激的促生存PI 3 K-Akt途径和mTOR的HCV不仅保护细胞免于凋亡，但也有助于维持稳态水平的HCV复制。这些影响可能有助于建立HCV的持续感染。
The hepatitis C virus (HCV) replication complex is localized within detergent-resistant membranes or lipid rafts. We analyzed the protein contents of detergent-resistant fractions isolated from Huh7 cells expressing a self-replicating full-length HCV-1b genome. Using two-dimensional gel electrophoresis followed by mass spectrometry, we identified N-Ras as one of the proteins in which expression was increased in the detergent-resistant fractions from HCV genomic replicon clones compared to control cells. N-Ras is an activator of the phosphatidylinositol-3-kinase (PI3K)-Akt pathway. We found that the activities of PI3K and Akt, as well as the activity of their downstream target, mTOR, in the HCV-replicating cells were increased. Both PI3K-Akt- and mTOR-dependent pathways have been shown to promote cell survival. In agreement with this, HCV replicon cells were resistant to serum starvation-induced apoptosis. We also characterized the role of this pathway in HCV replication. Reduction of N-Ras expression by transfection of N-Ras small interfering RNA (siRNA) resulted in increased replication of HCV. We observed a similar increase in HCV replication in cells treated with the PI3K inhibitor LY294002 and in cells transfected with mTOR siRNA. Taken together, these data suggest that increased N-Ras levels in subcellular sites of HCV replication and stimulation of the prosurvival PI3K-Akt pathway and mTOR by HCV not only protect cells against apoptosis but also contribute to the maintenance of steady-state levels of HCV replication. These effects may contribute to the establishment of persistent infection by HCV.