title: The N-terminal helix α(0) of hepatitis C virus NS3 protein dictates the subcellular localization and stability of NS3/NS4A complex.
abstract: The N-terminal amphipathic helix α(0) of hepatitis C virus (HCV) NS3 protein is an essential structural determinant for the protein membrane association. Here, we performed functional analysis to probe the role of this helix α(0) in the HCV life cycle. A point mutation M21P in this region that destroyed the helix formation disrupted the membrane association of NS3 protein and completely abolished HCV replication. Mechanistically the mutation did not affect either protease or helicase/NTPase activities of NS3, but significantly reduced the stability of NS3 protein. Furthermore, the membrane association and stability of NS3 protein can be restored by replacing the helix α(0) with an amphipathic helix of the HCV NS5A protein. In summary, our data demonstrated that the amphipathic helix α(0) of NS3 protein determines the proper membrane association of NS3, and this subcellular localization dictates the functional role of NS3 in the HCV life cycle.
authors.affiliation: Unit of Viral Hepatitis, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Science, Shanghai, 200025, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: He
authors.forename: Leiyun
authors.initials: L
authors.lastname: Weng
authors.forename: Rui
authors.initials: R
authors.lastname: Li
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Toyoda
authors.forename: Jin
authors.initials: J
authors.lastname: Zhong
mesh_terms: D002460:Cell Line; D002462:Cell Membrane; D004926:Escherichia coli / Q000378:metabolism; D015967:Gene Expression Regulation, Viral / Q000502:physiology; D016174:Hepacivirus / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D009154:Mutation; D043583:Nucleoside-Triphosphatase / Q000235:genetics / Q000378:metabolism; D055550:Protein Stability; D017433:Protein Structure, Secondary / Q000502:physiology*; D021381:Protein Transport; D017361:Viral Nonstructural Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012697:Serine Endopeptidases; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D043583:Nucleoside-Triphosphatase; D017361:Viral Nonstructural Proteins; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; C080106:NS4A protein, flavivirus