Hepatitis C virus NS3-NS4A serine protease complex (HCV NS3-NS4A protease)

The Hepatitis C virus (HCV) NS3-NS4A serine protease complex is a heterodimeric enzyme essential for the viral life cycle. The NS3 protein contains a serine protease domain at its N-terminus, which requires the NS4A protein as a cofactor to achieve full catalytic activity and proper membrane localization (UniProt P26664). This complex is responsible for the proteolytic processing of the HCV polyprotein at the NS3/4A, NS4A/4B, NS4B/5A, and NS5A/5B junctions, a process vital for generating functional viral proteins (Lindenbach & Rice, Nature, 2005). Additionally, the NS3-NS4A protease facilitates immune evasion by cleaving host signaling proteins such as MAVS (mitochondrial antiviral-signaling protein) and TRIF, thereby disrupting the induction of the host's innate antiviral response (Meylan et al., Nature, 2005). Due to its critical role in replication and immune suppression, it is a primary target for direct-acting antiviral (DAA) therapies. Protease inhibitors bind to the enzyme's active site or interfere with the NS3-NS4A interface to halt viral production and restore host immune signaling (AASLD/IDSA HCV Guidance).

Other names

NS3/4A proteaseHCV NS3-NS4A complexHCV serine proteaseNS3 proteaseNS3-NS4A heterodimer

Inhibition of the NS3-NS4A serine protease activity, preventing the cleavage of the viral polyprotein and blocking viral replication.