Human VAP-C negatively regulates hepatitis C virus propagation

J Virol. 2009 Aug;83(16):7959-69. doi: 10.1128/JVI.00889-09. Epub 2009 Jun 10.

Abstract

Human vesicle-associated membrane protein-associated protein (VAP) subtype A (VAP-A) and subtype B (VAP-B) are involved in the regulation of membrane trafficking, lipid transport and metabolism, and the unfolded protein response. VAP-A and VAP-B consist of the major sperm protein (MSP) domain, the coiled-coil motif, and the C-terminal transmembrane anchor and form homo- and heterodimers through the transmembrane domain. VAP-A and VAP-B interact with NS5B and NS5A of hepatitis C virus (HCV) through the MSP domain and the coiled-coil motif, respectively, and participate in the replication of HCV. VAP-C is a splicing variant of VAP-B consisting of the N-terminal half of the MSP domain of VAP-B followed by the subtype-specific frameshift sequences, and its biological function has not been well characterized. In this study, we have examined the biological functions of VAP-C in the propagation of HCV. VAP-C interacted with NS5B but not with VAP-A, VAP-B, or NS5A in immunoprecipitation analyses, and the expression of VAP-C inhibited the interaction of NS5B with VAP-A or VAP-B. Overexpression of VAP-C impaired the RNA replication of the HCV replicon and the propagation of the HCV JFH1 strain, whereas overexpression of VAP-A and VAP-B enhanced the replication. Furthermore, the expression of VAP-C was observed in various tissues, whereas it was barely detected in the liver. These results suggest that VAP-C acts as a negative regulator of HCV propagation and that the expression of VAP-C may participate in the determination of tissue tropism of HCV propagation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Down-Regulation*
  • Hepacivirus / genetics
  • Hepacivirus / physiology*
  • Hepatitis C / virology*
  • Humans
  • Protein Binding
  • Vesicular Transport Proteins / genetics
  • Vesicular Transport Proteins / metabolism*
  • Viral Nonstructural Proteins / genetics
  • Viral Nonstructural Proteins / metabolism
  • Virus Replication*

Substances

  • VAPA protein, human
  • VAPB protein, human
  • Vesicular Transport Proteins
  • Viral Nonstructural Proteins
  • NS-5 protein, hepatitis C virus