Influenza Virus A/Beijing/501/2009(H1N1)NS1 Interacts with β-Tubulin and Induces Disruption of the Microtubule Network and Apoptosis on A549 Cells

摘要

NS1 of influenza A virus is a key multifunctional protein that plays various roles in regulating viral replication mechanisms,host innate/adaptive immune responses,and cellular signalling pathways.These functions rely on its ability to participate in a multitude of protein-protein and protein-RNA interactions.To gain further insight into the role of NS1,a tandem affinity purification (TAP)method was utilized to find unknown interaction partner of NS1.The protein complexes of NS1 and its interacting partner were purified from A549 cell using TAP-tagged NS1 as bait.and co-purified cellular factors were identified hy mass spectrometry (MS).We identified cellular β-tubulin as a novel interaction partner of NS1.The RNA-binding domain of NS1 interacts with β-tuhulin through its RNA-hinding domain,as judged by a glutathione S-transferase (GST)pull-down assay with the GST-fused functional domains of NS1.Immunofluorescence analysis further revealed that NS1 with nucleolin co-locatized in the nucleus.In addition,the disruption of the microtubule network and apoptosis were also observed on NS1-transfected A549 cells.Our findings suggest that the 2009 pandemic H1N1 virus may utilize its NS1 protein to interact with cellular β-tubulin,further disrupt normal cell division and induce apoptosis,thereby facilitate virus replication and indirectly contribute to virus pathogenicity.