title: Oxysterol-binding protein is a phosphatidylinositol 4-kinase effector required for HCV replication membrane integrity and cholesterol trafficking.
abstract: OBJECTIVE
  Positive-sense RNA viruses remodel intracellular membranes to generate specialized membrane compartments for viral replication. Several RNA viruses, including poliovirus and hepatitis C virus (HCV), require phosphatidylinositol (PI) 4-kinases for their replication. However, it is not known how PI 4-kinases and their product, PI(4)P, facilitate host membrane reorganization and viral replication. In addition, although the HCV replication compartment, known as the membranous web, is believed to be cholesterol enriched, the mechanisms by which this occurs have not been elucidated. We aimed to identify and characterize a PI 4-kinase effector in HCV replication.
  
  
  METHODS
  We used a combination of microscopic and biochemical methods to study HCV replication, web morphology, the distribution of intracellular protein and PI(4)P, along with cholesterol trafficking in HCV-infected cells. PI 4-kinase and oxysterol-binding protein (OSBP) were inhibited using RNA interference or small molecules in cells expressing a full-length genotype 1b replicon or infected with the JFH-1 strain of HCV.
  
  
  RESULTS
  OSBP was required for HCV replication and membranous web integrity. OSBP was recruited to membranous webs in a PI 4-kinase-dependent manner, and both these factors were found to regulate cholesterol trafficking to the web. We also found OSBP to be required for poliovirus infection but dispensable for dengue virus.
  
  
  CONCLUSIONS
  OSBP is a PI 4-kinase effector in HCV infection, and contributes to the integrity and cholesterol enrichment of the membranous web. OSBP might also be a PI 4-kinase effector in poliovirus infection and could be involved in replication of other viruses that require PI 4-kinases.
authors: Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan.
authors: Hongliang
authors: H
authors: Wang
authors: Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan.
authors: Jeffrey W
authors: JW
authors: Perry
authors: Division of Infectious Diseases, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan; Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan.
authors: Adam S
authors: AS
authors: Lauring
authors: Virology Program, Istituto Nazionale di Genetica Molecolare (INGM), Milano, Italy.
authors: Petra
authors: P
authors: Neddermann
authors: Virology Program, Istituto Nazionale di Genetica Molecolare (INGM), Milano, Italy.
authors: Raffaele
authors: R
authors: De Francesco
authors: Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan; Division of Gastroenterology, Department of Internal Medicine, Ann Arbor Veterans Administration Health System, Ann Arbor, Michigan. Electronic address: andrewwt@med.umich.edu.
authors: Andrew W
authors: AW
authors: Tai
mesh_terms: D019870:1-Phosphatidylinositol 4-Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D001692:Biological Transport; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology*; D002784:Cholesterol / Q000378:metabolism*; D005838:Genotype; D057809:HEK293 Cells; D006367:HeLa Cells; D016174:Hepacivirus / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity; D054884:Host-Pathogen Interactions; D006801:Humans; D010641:Phenotype; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D034622:RNA Interference; D012367:RNA, Viral / Q000096:biosynthesis; D011987:Receptors, Steroid / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D017361:Viral Nonstructural Proteins / Q000378:metabolism; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication / Q000187:drug effects; D000098825:Oxysterol Binding Proteins; D012324:RNA-Dependent RNA Polymerase
chemical_list: D019870:1-Phosphatidylinositol 4-Kinase; D002784:Cholesterol; D018129:Phosphatidylinositol Phosphates; D047428:Protein Kinase Inhibitors; D012367:RNA, Viral; D011987:Receptors, Steroid; D017361:Viral Nonstructural Proteins; D014764:Viral Proteins; D000098825:Oxysterol Binding Proteins; C037178:phosphatidylinositol 4-phosphate; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase
keywords: Lipid Kinase; Lipid Transfer Proteins; Phosphatidylinositol 4-Phosphate; Viral Replication