Characterization of interactions between hepatitis C virus NS5B polymerase, annexin A2 and RNA - effects on NS5B catalysis and allosteric inhibition

Virol J. 2017 Dec 11;14(1):236. doi: 10.1186/s12985-017-0904-4.


Background: Direct acting antivirals (DAAs) provide efficient hepatitis C virus (HCV) therapy and clearance for a majority of patients, but are not available or effective for all patients. They risk developing HCV-induced hepatocellular carcinoma (HCC), for which the mechanism remains obscure and therapy is missing. Annexin A2 (AnxA2) has been reported to co-precipitate with the non-structural (NS) HCV proteins NS5B and NS3/NS4A, indicating a role in HCC tumorigenesis and effect on DAA therapy.

Methods: Surface plasmon resonance biosensor technology was used to characterize direct interactions between AnxA2 and HCV NS5B, NS3/NS4 and RNA, and the subsequent effects on catalysis and inhibition.

Results: No direct interaction between AnxA2 and NS3/NS4A was detected, while AnxA2 formed a slowly dissociating, high affinity (K D = 30 nM), complex with NS5B, decreasing its catalytic activity and affinity for the allosteric inhibitor filibuvir. The RNA binding of the two proteins was independent and AnxA2 and NS5B interacted with different RNAs in ternary complexes of AnxA2:NS5B:RNA, indicating specific preferences.

Conclusions: The complex interplay revealed between NS5B, AnxA2, RNA and filibuvir, suggests that AnxA2 may have an important role for the progression and treatment of HCV infections and the development of HCC, which should be considered also when designing new allosteric inhibitors.

Keywords: Annexin A2; Hepatitis C virus; Hepatocellular carcinoma; NS5B; RNA, allosteric inhibition, filibuvir, surface plasmon resonance.

MeSH terms

  • Allosteric Site
  • Animals
  • Annexin A2 / genetics
  • Annexin A2 / metabolism*
  • Antiviral Agents / pharmacology
  • Enzyme Inhibitors / pharmacology
  • Hepacivirus / drug effects
  • Hepacivirus / enzymology*
  • Hepatitis C / drug therapy
  • Hepatitis C / virology
  • Humans
  • Kinetics
  • Protein Binding / drug effects
  • Pyrones / pharmacology
  • RNA, Viral / metabolism*
  • RNA-Binding Proteins / metabolism
  • RNA-Dependent RNA Polymerase / antagonists & inhibitors
  • RNA-Dependent RNA Polymerase / metabolism
  • Substrate Specificity
  • Surface Plasmon Resonance
  • Triazoles / pharmacology
  • Viral Nonstructural Proteins / antagonists & inhibitors
  • Viral Nonstructural Proteins / metabolism*


  • Annexin A2
  • Antiviral Agents
  • Enzyme Inhibitors
  • Pyrones
  • RNA, Viral
  • RNA-Binding Proteins
  • Triazoles
  • Viral Nonstructural Proteins
  • filibuvir
  • NS-5 protein, hepatitis C virus
  • RNA-Dependent RNA Polymerase