The hepatitis E virus Orf3 protein protects cells from mitochondrial depolarization and death.
The hepatitis E virus Orf3 protein protects cells from mitochondrial depolarization and death.
复制标题
肝炎病毒ORF3蛋白可保护细胞免受线粒体去极化和死亡的影响。
DOI：
10.1074/jbc.m701696200
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发表时间：
2007-07-20
影响因子：
4.8
通讯作者：
Jameel, Shahid
中科院分区：
文献类型：
--
作者：
Moin, Syed Mohammad;Panteva, Milena;Jameel, Shahid
由于缺乏体外培养或感染模型，对戊型肝炎病毒的生物学和发病机制知之甚少。病毒Orf 3蛋白激活细胞促分裂原活化蛋白激酶途径，并可能调节宿主细胞环境以实现有效的病毒复制。我们筛选了在表达Orf 3的稳定细胞系（ORF 3/4）中转录差异上调的细胞基因。线粒体电压依赖性阴离子通道（VDAC）基因就是这样一个候选者。通过北方和蛋白质印迹法在各种细胞系中证实VDAC在ORF 3/4细胞中上调。用ORF 3特异性小干扰RNA转染ORF 3/4细胞导致VDAC蛋白水平降低。VDAC是一种重要的线粒体外膜蛋白，其过表达导致细胞凋亡。令人惊讶的是，通过保存线粒体电位和膜完整性，Orf 3表达细胞被保护免于星形孢菌素诱导的细胞死亡。Orf 3和VDAC水平的小干扰RNA介导的降低也使细胞对星形孢菌素敏感。化学交联显示Orf 3表达细胞含有更高水平的寡聚VDAC。这些细胞还含有更高水平的直接与VDAC相互作用的己糖激酶I。已知这种相互作用可保持线粒体电位并防止细胞色素c释放。我们在这里报告的第一个例子的病毒蛋白通过这种机制促进细胞存活。
The biology and pathogenesis of hepatitis E virus are poorly understood due to the lack of an in vitro culture or infection models. The viral Orf3 protein activates the cellular mitogen-activated protein kinase pathway and is likely to modulate the host cell environment for efficient viral replication. We screened for cellular genes whose transcription was differentially up-regulated in an Orf3-expressing stable cell line (ORF3/4). The gene for mitochondrial voltage-dependent anion channel (VDAC) was one such candidate. The up-regulation of VDAC in ORF3/4 cells was confirmed by Northern and Western blotting in various cell lines. Transfection of ORF3/4 cells with an ORF3-specific small interfering RNA led to a reduction in VDAC protein levels. VDAC is a critical mitochondrial outer membrane protein, and its overexpression results in apoptosis. Surprisingly, Orf3-expressing cells were protected against staurosporine-induced cell death by preservation of mitochondrial potential and membrane integrity. A small interfering RNA-mediated reduction in Orf3 and VDAC levels also made cells sensitive to staurosporine. Chemical cross-linking showed Orf3-expressing cells to contain higher levels of oligomeric VDAC. These cells also contained higher levels of hexokinase I that directly interacted with VDAC. This interaction is known to preserve mitochondrial potential and prevent cytochrome c release. We report here the first instance of a viral protein promoting cell survival through such a mechanism.