title: Influenza A virus non-structural protein 1 (NS1) interacts with cellular multifunctional protein nucleolin during infection.
abstract: Influenza A virus non-structural protein 1 (NS1) is the most important viral regulatory factor that controls cellular processes to facilitate viral replication. To gain further insight into the role of NS1, we tried to find novel cellular factors that interact with NS1. The complexes of NS1 and target proteins were pulled down from an infected cell lysate using anti-NS1 (A/Udorn/72) single-chain Fv and identified by peptide mass fingerprinting analysis. We identified nucleolin, a multifunctional major nucleolar protein, as a novel NS1-binding protein. The RNA-binding domain of NS1 was responsible for this binding, as judged by a GST (glutathione S-transferase) pull-down assay with the GST-fused functional domains of NS1. By laser confocal microscopy, we observed the co-localization of NS1 with nucleolin most clearly in the nucleoli, indicating that NS1 is interacting with nucleolin during infection. Our results suggest a novel function of NS1, namely, affecting cellular events via interaction with nucleolin.
authors.affiliation: Division of Infectious Disease Control, Department of Advanced Medical Science, Nihon University School of Medicine, 30-1 Oyaguchi-kamimachi, Itabashi, Tokyo 173-8610, Japan.
authors.forename: Rikinori
authors.initials: R
authors.lastname: Murayama
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Harada
authors.forename: Toshikatsu
authors.initials: T
authors.lastname: Shibata
authors.forename: Kazumichi
authors.initials: K
authors.lastname: Kuroda
authors.forename: Satoshi
authors.initials: S
authors.lastname: Hayakawa
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Shimizu
authors.forename: Torahiko
authors.initials: T
authors.lastname: Tanaka
mesh_terms: D045744:Cell Line, Tumor; D006801:Humans; D009980:Influenza A virus / Q000502:physiology*; D007251:Influenza, Human / Q000378:metabolism* / Q000821:virology*; D008175:Lung Neoplasms / Q000378:metabolism* / Q000821:virology*; D010750:Phosphoproteins / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000378:metabolism*; D017361:Viral Nonstructural Proteins / Q000378:metabolism*; D000097796:Nucleolin
chemical_list: D010750:Phosphoproteins; D016601:RNA-Binding Proteins; D017361:Viral Nonstructural Proteins; D000097796:Nucleolin; C085820:INS1 protein, influenza virus