title: A host YB-1 ribonucleoprotein complex is hijacked by hepatitis C virus for the control of NS3-dependent particle production.
abstract: Hepatitis C virus (HCV) orchestrates the different stages of its life cycle in time and space through the sequential participation of HCV proteins and cellular machineries; hence, these represent tractable molecular host targets for HCV elimination by combination therapies. We recently identified multifunctional Y-box-binding protein 1 (YB-1 or YBX1) as an interacting partner of NS3/4A protein and HCV genomic RNA that negatively regulates the equilibrium between viral translation/replication and particle production. To identify novel host factors that regulate the production of infectious particles, we elucidated the YB-1 interactome in human hepatoma cells by a quantitative mass spectrometry approach. We identified 71 YB-1-associated proteins that included previously reported HCV regulators DDX3, heterogeneous nuclear RNP A1, and ILF2. Of the potential YB-1 interactors, 26 proteins significantly modulated HCV replication in a gene-silencing screening. Following extensive interaction and functional validation, we identified three YB-1 partners, C1QBP, LARP-1, and IGF2BP2, that redistribute to the surface of core-containing lipid droplets in HCV JFH-1-expressing cells, similarly to YB-1 and DDX6. Importantly, knockdown of these proteins stimulated the release and/or egress of HCV particles without affecting virus assembly, suggesting a functional YB-1 protein complex that negatively regulates virus production. Furthermore, a JFH-1 strain with the NS3 Q221L mutation, which promotes virus production, was less sensitive to this negative regulation, suggesting that this HCV-specific YB-1 protein complex modulates an NS3-dependent step in virus production. Overall, our data support a model in which HCV hijacks host cell machinery containing numerous RNA-binding proteins to control the equilibrium between viral RNA replication and NS3-dependent late steps in particle production.
authors.affiliation: Institut de Recherche en Immunologie et en Cancérologie.
authors.forename: Laurent
authors.initials: L
authors.lastname: Chatel-Chaix
authors.forename: Marie-Anne
authors.initials: MA
authors.lastname: Germain
authors.forename: Alena
authors.initials: A
authors.lastname: Motorina
authors.forename: Éric
authors.initials: É
authors.lastname: Bonneil
authors.forename: Pierre
authors.initials: P
authors.lastname: Thibault
authors.forename: Martin
authors.initials: M
authors.lastname: Baril
authors.forename: Daniel
authors.initials: D
authors.lastname: Lamarre
mesh_terms: D002460:Cell Line; D020868:Gene Silencing; D016174:Hepacivirus / Q000502:physiology*; D022781:Hepatocytes / Q000737:chemistry; D054884:Host-Pathogen Interactions; D006801:Humans; D046911:Macromolecular Substances; D013058:Mass Spectrometry; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D020125:Mutation, Missense; D011485:Protein Binding; D055503:Protein Multimerization; D012367:RNA, Viral / Q000378:metabolism*; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication; D051840:Y-Box-Binding Protein 1 / Q000378:metabolism*; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D046911:Macromolecular Substances; D050505:Mutant Proteins; D012367:RNA, Viral; D017361:Viral Nonstructural Proteins; D051840:Y-Box-Binding Protein 1; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; C070856:YBX1 protein, human