Great progress has been made over the past years in elucidating the structure 
and function of the hepatitis C virus (HCV) proteins, most of which are now 
actively being pursued as antiviral targets. The structural proteins, which form 
the viral particle, include the core protein and the envelope glycoproteins E1 
and E2. The nonstructural proteins include the p7 viroporin, the NS2 protease, 
the NS3-4A complex harboring protease and NTPase/RNA helicase activities, the 
NS4B and NS5A proteins, and the NS5B RNA-dependent RNA polymerase. NS4B is a 
master organizer of replication complex formation while NS5A is a 
zinc-containing phosphoprotein involved in the regulation of HCV RNA replication 
versus particle production. Core to NS2 make up the assembly module while NS3 to 
NS5B represent the replication module (replicase). However, HCV proteins exert 
multiple functions during the viral life cycle, and these may be governed by 
different structural conformations and/or interactions with viral and/or 
cellular partners. Remarkably, each viral protein is anchored to intracellular 
membranes via specific determinants that are essential to protein function in 
the cell. This review summarizes current knowledge of the structure and function 
of the HCV proteins and highlights recent advances in the field.