Non-structural protein 1 (flavivirus) (NS1)

Non-structural protein 1 (NS1) is a highly conserved glycoprotein encoded by flaviviruses, including dengue, Zika, yellow fever, West Nile, and Japanese encephalitis viruses. It consists of 352 amino acids and exists in multiple forms: intracellular dimeric NS1 (involved in genome replication and assembly), membrane-associated NS1 (cell surface), and secreted hexameric NS1 (mediates immune evasion and endothelial dysfunction). NS1 does not form part of the virion structure but is crucial for viral replication, virion maturation, and pathogenesis—contributing to immune evasion by binding complement proteins, disrupting the glycocalyx of endothelial cells, and supporting viral immune escape. NS1 is an important diagnostic biomarker (especially for dengue), and a promising but challenging therapeutic target for antiviral drugs and vaccines aimed at preventing severe flavivirus infections[1][2][3][5].

Other names

NS1gp48 (historical name)Soluble complement fixing antigen (SCF) (historical context)[3]

Drugs (such as antibodies or vaccines) targeting NS1 aim to neutralize its immune evasion function, block its role in endothelial dysfunction, and prevent viral replication and dissemination[1][3]