Proteolytic Processing
Viral proteolytic processing occurs within the rough endoplasmic reticulum. First, cellular proteases cleave the core, E1, E2, and p7 proteins. Next, the NS2 cysteine protease, in conjunction with the N-terminal end of the NS3 protein, cleaves NS2 from NS3. Last, NS3, assisted by the membrane bound NS4A, forms an NS3-4A protease complex that cleaves the remaining proteins (NS3, NS4A, NS4B, NS5A, NS5B). The final result is 10 mature HCV proteins, including structural and nonstructural proteins.