The predominant species of nonstructural protein 4B in hepatitis C virus-replicating cells is not palmitoylated.
Hepatitis C virus (HCV) represents a significant global health burden. Viral replication is thought to occur in close association with remodelled host cell membranes, with non-structural protein 4B (NS4B) being a key player in this process. NS4B is a poorly characterized integral membrane protein, which has been reported to be palmitoylated at its carboxy-terminal end. In order to extend this observation and to establish a functional role for NS4B palmitoylation, we sought to determine the status of this post-translational modification when the protein was expressed as part of a functional viral replicase. We performed direct metabolic labelling and polyethylene glycol-maleimide palmitoylation reporter assays on NS4B expressed in cells containing subgenomic replicons and infectious viral RNA. In a vaccinia virus-based expression system NS4B palmitoylation was detected in a genotype-dependent manner. However, in spite of the high sensitivity of the methods used, no NS4B palmitoylation was found in physiologically more relevant systems. Thus, NS4B palmitoylation is most likely dispensable for HCV RNA replication.
1Department of Infectious Diseases, Molecular Virology, University of Heidelberg, 69120 Heidelberg, Germany.
David
D
Paul
1Department of Infectious Diseases, Molecular Virology, University of Heidelberg, 69120 Heidelberg, Germany.
Ralf
R
Bartenschlager
2Faculty of Medicine and Institute for Life Science, University of Southampton, Southampton SO16 6YD, UK.
Christopher
C
McCormick
D002460:Cell Line; D015870:Gene Expression; D005822:Genetic Vectors; D016174:Hepacivirus / Q000502:physiology*; D022781:Hepatocytes / Q000821:virology; D006801:Humans; D054878:Lipoylation; D011499:Protein Processing, Post-Translational; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D014616:Vaccinia virus / Q000235:genetics; D017361:Viral Nonstructural Proteins / Q000737:chemistry* / Q000378:metabolism*
C080107:NS4B protein, flavivirus; D011994:Recombinant Proteins; D017361:Viral Nonstructural Proteins