title: Viroporin Activity of the Foot-and-Mouth Disease Virus Non-Structural 2B Protein.
abstract: 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 Ca(2+) 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.
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China; College of Veterinary Medicine, Sichuan Agricultural University, Ya'an, Sichuan, China.
authors.forename: Da
authors.initials: D
authors.lastname: Ao
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China.
authors.forename: Hui-Chen
authors.initials: HC
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China.
authors.forename: Shi-Qi
authors.initials: SQ
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China.
authors.forename: De-Hui
authors.initials: DH
authors.lastname: Sun
authors.affiliation: School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
authors.forename: To Sing
authors.initials: TS
authors.lastname: Fung
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China.
authors.forename: Yan-Quan
authors.initials: YQ
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China.
authors.forename: Shi-Chong
authors.initials: SC
authors.lastname: Han
authors.affiliation: College of Veterinary Medicine, Sichuan Agricultural University, Ya'an, Sichuan, China.
authors.forename: Xue-Ping
authors.initials: XP
authors.lastname: Yao
authors.affiliation: College of Veterinary Medicine, Sichuan Agricultural University, Ya'an, Sichuan, China.
authors.forename: Sui-Zhong
authors.initials: SZ
authors.lastname: Cao
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China; School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
authors.forename: Ding Xiang
authors.initials: DX
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Veterinary Etiological Biology and OIE/National Foot and Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China.
authors.forename: Xiang-Tao
authors.initials: XT
authors.lastname: Liu
mesh_terms: D000547:Amantadine / Q000494:pharmacology; D000818:Animals; D001343:Autophagy / Q000235:genetics*; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D002463:Cell Membrane Permeability; D006224:Cricetinae; D004721:Endoplasmic Reticulum / Q000821:virology; D004926:Escherichia coli / Q000821:virology; D029544:Foot-and-Mouth Disease Virus / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D017434:Protein Structure, Tertiary; D017361:Viral Nonstructural Proteins / Q000037:antagonists & inhibitors*; D054334:Viral Regulatory and Accessory Proteins / Q000037:antagonists & inhibitors*; D057074:Virus Release / Q000187:drug effects; D014779:Virus Replication / Q000502:physiology
chemical_list: D017361:Viral Nonstructural Proteins; D054334:Viral Regulatory and Accessory Proteins; D000547:Amantadine; D002118:Calcium