RNase L interacts with Filamin A to regulate actin dynamics and barrier function for viral entry.
RNase L interacts with Filamin A to regulate actin dynamics and barrier function for viral entry.
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DOI：
10.1128/mbio.02012-14
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发表时间：
2014-10-28
期刊：
影响因子：
6.4
通讯作者：
Hassel BA
中科院分区：
文献类型：
--
作者：
Malathi K;Siddiqui MA;Dayal S;Naji M;Ezelle HJ;Zeng C;Zhou A;Hassel BA
肌动蛋白细胞骨架及其相关蛋白网络构成了病毒必须绕过的物理屏障，以进入细胞进行生产性感染。感染的物理信号被宿主感知以激活先天免疫反应的机制还不清楚。抗病毒核糖核酸内切酶RNase L以潜伏形式广泛表达，并在结合2-5A（病毒感染期间产生的独特寡腺苷酸）时被激活。我们提供的证据表明，RNase L在其非活性形式与肌动蛋白结合蛋白细丝蛋白A相互作用，以调节肌动蛋白细胞骨架和抑制病毒进入。细胞缺乏核糖核酸酶L或细丝蛋白A显示增加的病毒进入，这是加剧细胞缺乏这两种蛋白质。减少细丝蛋白A相互作用的RNase L缺失突变体显示出限制病毒进入的折衷能力，支持RNase L-细丝蛋白A复合物在屏障功能中的重要作用的想法。值得注意的是，野生型和无催化活性的RNase L突变体都有能力在转染到RNase L缺陷细胞中时减少病毒进入，这表明RNase L的这种新功能不依赖于其酶活性。病毒感染和RNase L活化破坏其与细丝蛋白A的结合并释放RNase L以介导其典型的核酸酶依赖性抗病毒活性。RNase L作为肌动蛋白细胞骨架的组成成分和作为抗病毒信号传导和效应器功能的诱导介体的双重功能为其抗病毒活性机制提供了深入了解，并为开发新型抗病毒药物提供了机会。细胞不断地面对和采样其外表面上的病原体。肌动蛋白细胞骨架和相互作用的蛋白质与细胞膜结合，构成感染的屏障。肌动蛋白细胞骨架的破坏允许病毒进入细胞并诱导先天免疫应答以清除感染。将病毒诱导的物理扰动与宿主防御途径联系起来的分子机制仍不清楚。我们的研究确定了一种新的抗病毒核糖核酸内切酶RNase L和肌动蛋白结合蛋白细丝蛋白A之间的相互作用，通过防止病毒进入幼稚细胞，增强宿主防御。RNase L的这种作用与其酶功能无关。病毒感染改变肌动蛋白动力学，破坏RNase L-细丝蛋白A复合物，并释放RNase L，通过其已建立的溶核活性介导抗病毒信号传导和效应子功能。RNase L的这些双重作用提供了一种有效的策略，以保护细胞免受感染，并在病原体暴露后迅速作出反应。
The actin cytoskeleton and its network of associated proteins constitute a physical barrier that viruses must circumvent to gain entry into cells for productive infection. The mechanisms by which the physical signals of infection are sensed by the host to activate an innate immune response are not well understood. The antiviral endoribonuclease RNase L is ubiquitously expressed in a latent form and activated upon binding 2-5A, a unique oligoadenylate produced during viral infections. We provide evidence that RNase L in its inactive form interacts with the actin-binding protein Filamin A to modulate the actin cytoskeleton and inhibit virus entry. Cells lacking either RNase L or Filamin A displayed increased virus entry which was exacerbated in cells lacking both proteins. RNase L deletion mutants that reduced Filamin A interaction displayed a compromised ability to restrict virus entry, supporting the idea of an important role for the RNase L-Filamin A complex in barrier function. Remarkably, both the wild type and a catalytically inactive RNase L mutant were competent to reduce virus entry when transfected into RNase L-deficient cells, indicating that this novel function of RNase L is independent of its enzymatic activity. Virus infection and RNase L activation disrupt its association with Filamin A and release RNase L to mediate its canonical nuclease-dependent antiviral activities. The dual functions of RNase L as a constitutive component of the actin cytoskeleton and as an induced mediator of antiviral signaling and effector functions provide insights into its mechanisms of antiviral activity and opportunities for the development of novel antiviral agents. Cells constantly face and sample pathogens on their outer surface. The actin cytoskeleton and interacting proteins associate with the cell membrane and constitute a barrier to infection. Disruption of the actin cytoskeleton allows viruses to enter the cell and induces innate immune responses to clear infections. The molecular mechanisms that link virus-induced physical perturbations to host defense pathways remain unclear. Our studies identified a novel interaction between the antiviral endoribonuclease RNase L and the actin-binding protein Filamin A that enhances host defense by preventing viral entry into naive cells. This role for RNase L is independent of its enzymatic function. Virus infection alters actin dynamics, disrupts the RNase L-Filamin A complex, and releases RNase L to mediate antiviral signaling and effector functions via its established nucleolytic activities. These dual roles for RNase L provide an efficient strategy to protect cells from infection and rapidly respond upon pathogen exposure.