Hepatitis C virus non-structural protein 3 serine protease (NS3 protease)

Hepatitis C virus non-structural protein 3 serine protease (NS3 protease) is an essential viral enzyme with a trypsin-like serine protease domain located at its N-terminus and a helicase domain at its C-terminus[3][5]. NS3 protease requires the cofactor NS4A to form a stable, active complex (NS3/4A), which is responsible for processing the HCV polyprotein into mature viral proteins required for viral replication[2][5]. In addition, NS3/4A mediates immune evasion by cleaving key host innate immune signaling proteins, such as mitochondrial antiviral signaling protein (MAVS), thereby disrupting interferon signaling and blunting the host antiviral response[1]. NS3 protease is a well-validated therapeutic target; multiple classes of direct-acting antivirals—most notably protease inhibitors such as boceprevir, telaprevir, simeprevir, paritaprevir, and glecaprevir—are approved or in development for chronic hepatitis C, often in combination regimens[2][4][6]. Resistance mutations, adverse effects, and drug interactions remain primary clinical challenges[4]. NS3 protease is unique to hepatitis C virus and plays no direct role in human cellular physiology.

Other names

HCV NS3-4A proteaseHepatitis C virus NS3/4A proteaseNS3-4ANS3 serine protease

Protease inhibition (prevents viral polyprotein processing and viral maturation) Targeted protein degradation (for experimental degraders) Blockade of immune evasion by HCV