title: The mechanism of HCV entry into host cells.
abstract: Hepatitis C virus (HCV) is an enveloped, positive strand RNA virus classified within the Flaviviridae family and is a major cause of liver disease worldwide. HCV life cycle and propagation are tightly linked to several aspects of lipid metabolism. HCV propagation depends on and also shapes several aspects of lipid metabolism such as cholesterol uptake and efflux through different lipoprotein receptors during its entry into cells, lipid metabolism modulating HCV genome replication, lipid droplets acting as a platform for recruitment of viral components, and very low density lipoprotein assembly pathway resulting in incorporation of neutral lipids and apolipoproteins into viral particles. During the first steps of infection, HCV enters hepatocytes through a multistep and slow process. The initial capture of HCV particles by glycosaminoglycans and/or lipoprotein receptors is followed by coordinated interactions with the scavenger receptor class B type I, a major receptor of high-density lipoprotein, the CD81 tetraspanin, and the tight junction proteins Claudin-1 and Occludin. This tight concert of receptor interactions ultimately leads to uptake and cellular internalization of HCV through a process of clathrin-dependent endocytosis. Over the years, the identification of the HCV entry receptors and cofactors has led to a better understanding of HCV entry and of the narrow tropism of HCV for the liver. Yet, the role of the two HCV envelope glycoproteins, E1 and E2, remains ill-defined, particularly concerning their involvement in the membrane fusion process. Here, we review the current knowledge and advances addressing the mechanism of HCV cell entry within hepatocytes and we highlight the challenges that remain to be addressed.
authors.affiliation: CIRI, International Center for Infectiology Research, Team EVIR, Université de Lyon, Lyon, France; Inserm U1111, Lyon, France; Ecole Normale Supérieure de Lyon, Lyon, France; Centre International de Recherche en Infectiologie, Université Claude Bernard Lyon 1, Lyon, France; CNRS, UMR5308, Lyon, France; LabEx Ecofect, Université de Lyon, Lyon, France; CNRS, UMR 5557 Ecologie Microbienne, Microbial Dynamics and Viral Transmission Team, Université Claude Bernard Lyon 1, Villeurbanne, France.
authors.forename: Florian
authors.initials: F
authors.lastname: Douam
authors.affiliation: CIRI, International Center for Infectiology Research, Team EVIR, Université de Lyon, Lyon, France; Inserm U1111, Lyon, France; Ecole Normale Supérieure de Lyon, Lyon, France; Centre International de Recherche en Infectiologie, Université Claude Bernard Lyon 1, Lyon, France; CNRS, UMR5308, Lyon, France; CNRS, UMR 5557 Ecologie Microbienne, Microbial Dynamics and Viral Transmission Team, Université Claude Bernard Lyon 1, Villeurbanne, France.
authors.forename: Dimitri
authors.initials: D
authors.lastname: Lavillette
authors.affiliation: CIRI, International Center for Infectiology Research, Team EVIR, Université de Lyon, Lyon, France; Inserm U1111, Lyon, France; Ecole Normale Supérieure de Lyon, Lyon, France; Centre International de Recherche en Infectiologie, Université Claude Bernard Lyon 1, Lyon, France; CNRS, UMR5308, Lyon, France; LabEx Ecofect, Université de Lyon, Lyon, France. Electronic address: flcosset@ens-lyon.fr.
authors.forename: François-Loïc
authors.initials: FL
authors.lastname: Cosset
mesh_terms: D016174:Hepacivirus / Q000502:physiology*; D054884:Host-Pathogen Interactions; D006801:Humans; D008561:Membrane Fusion; D011956:Receptors, Cell Surface / Q000378:metabolism; D014771:Virion / Q000502:physiology; D053586:Virus Internalization
chemical_list: D011956:Receptors, Cell Surface
keywords: Envelope glycoproteins; Hepatitis C virus; Membrane fusion; Receptor; Virus entry