title: Identification of FBL2 as a geranylgeranylated cellular protein required for hepatitis C virus RNA replication.
abstract: We recently reported that Hepatitis C virus (HCV) RNA replication requires one or more geranylgeranylated host proteins. Using a combination of [(3)H]mevalonate labeling, coimmunoprecipitation, and bioinformatic search, we identified a geranylgeranylated host protein required for HCV RNA replication. This protein, FBL2, contains an F box domain and a CAAX motif (CVIL). It forms a stable immunoprecipitable complex with the HCV nonstructural protein 5A (NS5A). The association of FBL2 with NS5A requires the CAAX motif of FBL2, but not the F box. Deletion of the F box created a dominant-negative protein that inhibited replication of HCV RNA when overexpressed in Huh7-K2040 cells; this inhibition was overcome by coexpression of NS5A. siRNA-mediated knockdown of FBL2 mRNA by 70% in Huh7-HP cells reduced HCV RNA by 65%; this reduction was overcome by expression of a cDNA encoding a wobble mutant of FBL2. The current data indicate that geranylgeranylated FBL2 binds to NS5A in a reaction crucial for HCV RNA replication.
authors.affiliation: Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA.
authors.forename: Chunfu
authors.initials: C
authors.lastname: Wang
authors.forename: Michael
authors.initials: M
authors.lastname: Gale
authors.forename: Brian C
authors.initials: BC
authors.lastname: Keller
authors.forename: Hua
authors.initials: H
authors.lastname: Huang
authors.forename: Michael S
authors.initials: MS
authors.lastname: Brown
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Goldstein
authors.forename: Jin
authors.initials: J
authors.lastname: Ye
mesh_terms: D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D004224:Diterpenes / Q000378:metabolism*; D044783:F-Box Proteins / Q000235:genetics / Q000378:metabolism*; D016174:Hepacivirus / Q000502:physiology*; D006801:Humans; D008798:Mevalonic Acid; D012367:RNA, Viral / Q000096:biosynthesis; D014316:Tritium; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism; D014902:West Nile virus / Q000235:genetics / Q000378:metabolism; D012324:RNA-Dependent RNA Polymerase
chemical_list: D018797:Cell Cycle Proteins; D004224:Diterpenes; D044783:F-Box Proteins; D008798:Mevalonic Acid; D012367:RNA, Viral; D014316:Tritium; D017361:Viral Nonstructural Proteins; C122028:FBXL2 protein, human; C040155:geranylgeranic acid; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase