title: Productive Entry of Foot-and-Mouth Disease Virus via Macropinocytosis Independent of Phosphatidylinositol 3-Kinase.
abstract: Virus entry is an attractive target for therapeutic intervention. Here, using a combination of electron microscopy, immunofluorescence assay, siRNA interference, specific pharmacological inhibitors, and dominant negative mutation, we demonstrated that the entry of foot-and-mouth disease virus (FMDV) triggered a substantial amount of plasma membrane ruffling. We also found that the internalization of FMDV induced a robust increase in fluid-phase uptake, and virions internalized within macropinosomes colocalized with phase uptake marker dextran. During this stage, the Rac1-Pak1 signaling pathway was activated. After specific inhibition on actin, Na(+)/H(+) exchanger, receptor tyrosine kinase, Rac1, Pak1, myosin II, and protein kinase C, the entry and infection of FMDV significantly decreased. However, inhibition of phosphatidylinositol 3-kinase (PI3K) did not reduce FMDV internalization but increased the viral entry and infection to a certain extent, implying that FMDV entry did not require PI3K activity. Results showed that internalization of FMDV exhibited the main hallmarks of macropinocytosis. Moreover, intracellular trafficking of FMDV involves EEA1/Rab5-positive vesicles. The present study demonstrated macropinocytosis as another endocytic pathway apart from the clathrin-mediated pathway. The findings greatly expand our understanding of the molecular mechanisms of FMDV entry into cells, as well as provide potential insights into the entry mechanisms of other picornaviruses.
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: 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: Ye
authors.initials: Y
authors.lastname: Jin
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: Xia
authors.initials: X
authors.lastname: Feng
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.
authors.forename: Ding
authors.initials: D
authors.lastname: Xiang 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: D000199:Actins / Q000378:metabolism; D000818:Animals; D022461:Caveolins / Q000378:metabolism; D002460:Cell Line; D002784:Cholesterol / Q000378:metabolism; D029544:Foot-and-Mouth Disease Virus / Q000502:physiology*; D008563:Membrane Lipids / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010873:Pinocytosis; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D053586:Virus Internalization; D014779:Virus Replication
chemical_list: D000199:Actins; D022461:Caveolins; D008563:Membrane Lipids; D002784:Cholesterol; D019869:Phosphatidylinositol 3-Kinases; D020794:Receptor Protein-Tyrosine Kinases