Identification of FBL2 as a Geranylgeranylated Cellular Protein Required for Hepatitis C Virus RNA Replication

Mol Cell. 2005 May 13;18(4):425-34. doi: 10.1016/j.molcel.2005.04.004.

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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cell Line
  • Diterpenes / metabolism*
  • F-Box Proteins / genetics
  • F-Box Proteins / metabolism*
  • Hepacivirus / physiology*
  • Humans
  • Mevalonic Acid
  • RNA, Viral / biosynthesis
  • Tritium
  • Viral Nonstructural Proteins / genetics
  • Viral Nonstructural Proteins / metabolism
  • West Nile virus / genetics
  • West Nile virus / metabolism

Substances

  • Cell Cycle Proteins
  • Diterpenes
  • F-Box Proteins
  • FBXL2 protein, human
  • NS-5 protein, hepatitis C virus
  • RNA, Viral
  • Viral Nonstructural Proteins
  • Tritium
  • geranylgeranic acid
  • Mevalonic Acid