Poxviral regulation of the host NF-κB response:: The vaccinia virus M2L protein inhibits induction of NF-κ13 activation via an ERK2 pathway in virus-infected human embryonic kidney cells
Poxviral regulation of the host NF-κB response:: The vaccinia virus M2L protein inhibits induction of NF-κ13 activation via an ERK2 pathway in virus-infected human embryonic kidney cells
复制标题
DOI：
10.1128/jvi.00935-06
复制
发表时间：
2006-09-01
影响因子：
5.4
通讯作者：
Shisler, Joanna L.
中科院分区：
文献类型：
--
作者：
Gedey, Roderick;Jin, Xiao-Lu;Shisler, Joanna L.
真核细胞暴露于病毒将激活宿主NF-κ B转录因子，导致促炎和免疫蛋白的产生。牛痘病毒（W），原型正痘病毒，表达抑制这种抗病毒事件的产物。为了确定这种效应的新机制，我们使用了一种W缺失突变体（MVA），它刺激受感染的293 T细胞中NF-κ B活化。在该病毒-宿主系统中，在PD 98059或U 0126（两种能够阻断ERK 1和ERK 2磷酸化的化合物）存在下，NF-κ B调节的基因表达和核转位的程度降低。在含有显性、非活性形式的ERK 2的细胞中也观察到类似的抑制，但在通过显性阴性突变体MEK 1蛋白的过表达抑制ERK 1磷酸化的细胞中没有观察到类似的抑制。据推测，从野生型W表达的阻断ERK 2活性的蛋白质也将抑制MVA诱导的NF-κ B活化。事实上，一个这样的开放阅读框架M2 L的表达支持了这一预测。首先，异位M2 L表达阻碍了暴露于佛波醇肉豆蔻酸酯乙酸酯诱导的ERK 2磷酸化。第二，通过用稳定表达M2 L的重组MVA构建体感染细胞的病毒M2 L表达与用亲本MVA菌株感染的细胞相比降低了ERK 2的磷酸化。最后，表达M2 L的重组病毒恢复了“野生型”NF-κ B抑制表型，如NF-κ B迁移到感染细胞核的减少和转录的干扰所示。因此，在293 T细胞中，W显然利用其M2 L蛋白来干扰否则将使ERK 2磷酸化和随后的NF-κ B应答活化的步骤。
Exposure of eukaryotic cells to viruses will activate the host NF-kappa B transcription factor, resulting in proinflammatory and immune protein production. Vaccinia virus (W), the prototypic orthopoxvirus, expresses products that inhibit this antiviral event. To identify novel mechanisms responsible for this effect, we made use of a W deletion mutant (MVA) that stimulates NF-kappa B activation in infected 293T cells. In this virus-host system, the extents of NF-kappa B-regulated gene expression and nuclear translocation were reduced in the presence of either PD 98059 or U0126, two compounds capable of blocking ERK1 and ERK2 phosphorylation. A similar repression was also observed in cells that contained a dominant, nonactive form of ERK2 but not in cells where ERK1 phosphorylation was inhibited via overexpression of a dominant-negative mutant MEK1 protein. Presumably, proteins expressed from a wild-type W that block ERK2 activity would also inhibit MVA-induced NF-kappa B activation. Indeed, the expression of one such open reading frame, M2L, supported this prediction. First, ectopic M2L expression hampered ERK2 phosphorylation induced by exposure to phorbol myristate acetate. Second, viral M2L expression via infection of cells with a recombinant MVA construct that stably expressed M2L decreased the phosphorylation of ERK2 compared to that in cells infected with the parental MVA strain. Finally, the recombinant M2L-expressing virus restored the "wild-type" NF-kappa B-inhibitory phenotype, as indicated by decreased NF-kappa B migration to infected cell nuclei and interference in transcription. Thus, in 293T cells, W apparently utilizes its M2L protein to interfere with a step(s) that would otherwise enable ERK2 phosphorylation and the consequential activation of an NF-kappa B response.