Review Article

Lipoprotein Receptors and Lipid Enzymes in Hepatitis C Virus Entry and Early Steps of Infection

Figure 1

Schematic representations of the hepatitis C virus. (a) In the absence of three-dimensional structures of the virion or any of its structural proteins (the envelope proteins E1-E2 and the core protein), HCV is represented roughly as a sphere without any symmetry. The E1-E2 glycoproteins (blue and pink, resp.) are set in the viral envelope (red) via their transmembrane domains. Their distribution at the particle surface is left loose on purpose, since currently available high resolution cryo-TEM (transmission electron microscopy) examinations did not show any high-density layer of proteins on the lipid envelope [23, 24]. The internal layer is formed by the core protein (green) compacting the viral RNA genome (black); no structural information is available about the nucleocapsid and its arrangement (illustration by J.-F. Michel). “This research was originally published in [8].” (b) Structural organization of a lipoprotein. The lipid core is composed of cholesterol esters (pink) and triglycerides (green); it is surrounded by a monolayer of phospholipids (blue), into which free cholesterol molecules are inserted (yellow). Apolipoproteins (purple) are inserted into the lipid layer of this particle. (c) Schematic representation of a lipo-viro-particle (LVP), where HCV nucleocapsid is embedded in the lipid core of the lipoprotein, harboring apolipoproteins and HCV E1-E2 glycoproteins at their surface.