title: Hepatitis C virus NS5A protein interacts with lysine methyltransferase SET and MYND domain-containing 3 and induces activator protein 1 activation.
abstract: Hepatitis C virus (HCV) non-structural protein 5A (NS5A) is a multifunctional protein that is involved in the HCV life cycle and pathogenesis. In this study, a host protein(s) interacting with NS5A by tandem affinity purification were searched for with the aim of elucidating the role of NS5A. An NS5A-interacting protein, SET and MYND domain-containing 3 (SMYD3), a lysine methyltransferase reportedly involved in the development of cancer, was identified. The interaction between NS5A and SMYD3 was confirmed in ectopically expressing, HCV RNA replicon-harboring and HCV-infected cells. The other HCV proteins did not bind to SMYD3. SMYD3 bound to NS5A of HCV genotypes 1b and 2a. Deletion mutational analysis revealed that domains II and III of NS5A (amino acids [aa] 250 to 447) and the MYND and N-SET domains of SMYD3 (aa 1 to 87) are involved in the full extent of NS5A-SMYD3 interaction. NS5A co-localized with SMYD3 exclusively in the cytoplasm, thereby inhibiting nuclear localization of SMYD3. Moreover, NS5A formed a complex with SMYD3 and heat shock protein 90 (HSP90), which is a positive regulator of SMYD3. The intensity of binding between SMYD3 and HSP90 was enhanced by NS5A. Luciferase reporter assay demonstrated that NS5A significantly induces activator protein 1 (AP-1) activity, this being potentiated by co-expression of SMYD3 with NS5A. Taken together, the present results suggest that NS5A interacts with SMYD3 and induces AP-1 activation, possibly by facilitating binding between HSP90 and SMYD3. This may be a novel mechanism of AP-1 activation in HCV-infected cells.
authors.affiliation: Division of Microbiology.|Division of Infectious Disease Control, Kobe University Graduate School of Medicine.
authors.forename: Ming
authors.initials: M
authors.lastname: Chen
authors.affiliation: Division of Microbiology.|Institute of Biochemistry and Molecular Biology, Hubei University, Wuhan, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Gan
authors.affiliation: Biosignal Research Center, Kobe University.
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Yoshino
authors.affiliation: Department of Biology, Faculty of Science, Kobe University.
authors.forename: Madoka
authors.initials: M
authors.lastname: Kitakawa
authors.affiliation: Division of Infectious Disease Control, Kobe University Graduate School of Medicine.
authors.forename: Ikuo
authors.initials: I
authors.lastname: Shoji
authors.affiliation: Division of Microbiology.|Division of Infectious Disease Control, Kobe University Graduate School of Medicine.
authors.forename: Lin
authors.initials: L
authors.lastname: Deng
authors.affiliation: Division of Microbiology.|Department of Oral Vaccine and Drug Development, Kobe University Graduate School of Health Sciences, Kobe, Japan.
authors.forename: Hak
authors.initials: H
authors.lastname: Hotta
mesh_terms: D002460:Cell Line; D003593:Cytoplasm / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism; D016174:Hepacivirus / Q000235:genetics / Q000378:metabolism*; D006526:Hepatitis C / Q000821:virology; D011495:Histone-Lysine N-Methyltransferase / Q000096:biosynthesis / Q000378:metabolism*; D054884:Host-Pathogen Interactions; D006801:Humans; D025941:Protein Interaction Mapping / Q000379:methods; D060066:Protein Interaction Maps; D012093:Replicon / Q000502:physiology; D020539:Sequence Analysis, Protein; D017384:Sequence Deletion; D018808:Transcription Factor AP-1 / Q000096:biosynthesis* / Q000378:metabolism*; D017361:Viral Nonstructural Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication / Q000502:physiology; D012324:RNA-Dependent RNA Polymerase
chemical_list: D018841:HSP90 Heat-Shock Proteins; D011495:Histone-Lysine N-Methyltransferase; D018808:Transcription Factor AP-1; D017361:Viral Nonstructural Proteins; C506278:SMYD3 protein, human; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase
keywords: NS5A; SMYD3; activator protein 1; hepatitis C virus