Viroporin Activity of the Foot-and-Mouth Disease Virus Non-Structural 2B Protein.
Viroporin Activity of the Foot-and-Mouth Disease Virus Non-Structural 2B Protein.
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DOI：
10.1371/journal.pone.0125828
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Liu XT
中科院分区：
文献类型：
--
作者：
Ao D;Guo HC;Sun SQ;Sun DH;Fung TS;Wei YQ;Han SC;Yao XP;Cao SZ;Liu DX;Liu XT
病毒孔蛋白是由多种动物病毒编码的低分子量疏水性跨膜蛋白家族。病毒孔蛋白通过寡聚化在宿主细胞中形成跨膜孔，从而破坏细胞稳态并诱导病毒复制和病毒体释放的细胞病变。在小核糖核酸病毒科的病毒中，由肠道病毒编码的2B蛋白是很好理解的，而由口蹄疫病毒（FMDV）编码的2B蛋白的病毒孔蛋白活性尚未被描述。通过计算机辅助程序对FMDV 2B蛋白结构域进行分析，发现该蛋白可能含有两个跨膜区。进一步的生物化学、生物物理学和功能研究表明，当该蛋白在细菌和哺乳动物细胞以及口蹄疫病毒感染的细胞中过表达时，它具有许多病毒孔蛋白的典型特征。发现该蛋白主要定位于内质网（ER），N-和C-末端结构域延伸到胞质溶胶中。它在大肠杆菌中表现出细胞毒性，这减弱了2B蛋白的表达。病毒孔蛋白抑制剂金刚烷胺可抑制口蹄疫病毒感染细胞释放病毒粒子。2B蛋白单体相互作用形成细胞内和细胞外寡聚体。细胞中的Ca 2+浓度增加，并且在表达2B蛋白的细胞中细胞质膜的完整性被破坏。此外，2B蛋白在宿主细胞中诱导强烈的自噬。本研究的所有结果表明FMDV 2B蛋白具有在其他病毒孔蛋白中也发现的性质，并且可能参与FMDV的感染机制。
Viroporins are a family of low-molecular-weight hydrophobic transmembrane proteins that are encoded by various animal viruses. Viroporins form transmembrane pores in host cells via oligomerization, thereby destroying cellular homeostasis and inducing cytopathy for virus replication and virion release. Among the Picornaviridae family of viruses, the 2B protein encoded by enteroviruses is well understood, whereas the viroporin activity of the 2B protein encoded by the foot-and-mouth disease virus (FMDV) has not yet been described. An analysis of the FMDV 2B protein domains by computer-aided programs conducted in this study revealed that this protein may contain two transmembrane regions. Further biochemical, biophysical and functional studies revealed that the protein possesses a number of features typical of a viroporin when it is overexpressed in bacterial and mammalian cells as well as in FMDV-infected cells. The protein was found to be mainly localized in the endoplasmic reticulum (ER), with both the N- and C-terminal domains stretched into the cytosol. It exhibited cytotoxicity in Escherichia coli, which attenuated 2B protein expression. The release of virions from cells infected with FMDV was inhibited by amantadine, a viroporin inhibitor. The 2B protein monomers interacted with each other to form both intracellular and extracellular oligomers. The Ca2+ concentration in the cells increased, and the integrity of the cytoplasmic membrane was disrupted in cells that expressed the 2B protein. Moreover, the 2B protein induced intense autophagy in host cells. All of the results of this study demonstrate that the FMDV 2B protein has properties that are also found in other viroporins and may be involved in the infection mechanism of FMDV.