title: Cellular binding of hepatitis C virus envelope glycoprotein E2 requires cell surface heparan sulfate.
abstract: The conservation of positively charged residues in the N terminus of the hepatitis C virus (HCV) envelope glycoprotein E2 suggests an interaction of the viral envelope with cell surface glycosaminoglycans. Using recombinant envelope glycoprotein E2 and virus-like particles as ligands for cellular binding, we demonstrate that cell surface heparan sulfate proteoglycans (HSPG) play an important role in mediating HCV envelope-target cell interaction. Heparin and liver-derived highly sulfated heparan sulfate but not other soluble glycosaminoglycans inhibited cellular binding and entry of virus-like particles in a dose-dependent manner. Degradation of cell surface heparan sulfate by pretreatment with heparinases resulted in a marked reduction of viral envelope protein binding. Surface plasmon resonance analysis demonstrated a high affinity interaction (KD 5.2 x 10-9 m) of E2 with heparin, a structural homologue of highly sulfated heparan sulfate. Deletion of E2 hypervariable region-1 reduced E2-heparin interaction suggesting that positively charged residues in the N-terminal E2 region play an important role in mediating E2-HSPG binding. In conclusion, our results demonstrate for the first time that cellular binding of HCV envelope requires E2-HSPG interaction. Docking of E2 to cellular HSPG may be the initial step in the interaction between HCV and the cell surface resulting in receptor-mediated entry and initiation of infection.
authors.affiliation: Department of Medicine II, University of Freiburg, D-79106 Freiburg, Germany.
authors.forename: Heidi
authors.initials: H
authors.lastname: Barth
authors.forename: Christiane
authors.initials: C
authors.lastname: Schafer
authors.forename: Mohammed I
authors.initials: MI
authors.lastname: Adah
authors.forename: Fuming
authors.initials: F
authors.lastname: Zhang
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Linhardt
authors.forename: Hidenao
authors.initials: H
authors.lastname: Toyoda
authors.forename: Akiko
authors.initials: A
authors.lastname: Kinoshita-Toyoda
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Toida
authors.forename: Toin H
authors.initials: TH
authors.lastname: Van Kuppevelt
authors.forename: Erik
authors.initials: E
authors.lastname: Depla
authors.forename: Fritz
authors.initials: F
authors.lastname: Von Weizsacker
authors.forename: Hubert E
authors.initials: HE
authors.lastname: Blum
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Baumert
mesh_terms: D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D002704:Chlorates / Q000494:pharmacology; D019281:Dimerization; D004187:Disaccharides / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D017353:Gene Deletion; D006497:Heparan Sulfate / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008024:Ligands; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D020349:Surface Plasmon Resonance; D013696:Temperature; D013997:Time Factors; D014759:Viral Envelope Proteins / Q000737:chemistry* / Q000378:metabolism
chemical_list: D002704:Chlorates; D004187:Disaccharides; D006497:Heparan Sulfate; D008024:Ligands; D014759:Viral Envelope Proteins; C091015:glycoprotein E2, Hepatitis C virus; C032706:sodium chlorate