Influenza A virus nucleoprotein and hemagglutinin (NP/HA)

Influenza A nucleoprotein (NP) and hemagglutinin (HA) are essential structural components of the Influenza A virus, serving distinct roles in the viral life cycle. Hemagglutinin is a surface glycoprotein that facilitates viral entry by binding to host cell sialic acid receptors and inducing membrane fusion within endosomes (UniProt P03435). Nucleoprotein is a highly conserved internal protein that encapsulates the viral RNA, forming the viral ribonucleoprotein (vRNP) complex necessary for RNA transcription, replication, and nuclear export (UniProt P03466). HA is the primary component of seasonal vaccines, though its high rate of antigenic drift necessitates frequent updates to match circulating strains. In contrast, NP's conservation makes it an attractive target for universal influenza vaccines and novel small-molecule inhibitors like nucleozin, which disrupt vRNP assembly. Together, these proteins are central to both the pathogenicity of the virus and the development of prophylactic and therapeutic interventions.

Other names

Influenza A NP and HAInfluenza A virus structural proteinsFlu A antigensNucleocapsid protein and Hemagglutinin surface glycoprotein

Hemagglutinin inhibitors prevent viral attachment to host sialic acid receptors and subsequent membrane fusion. Nucleoprotein inhibitors disrupt the formation, nuclear trafficking, or template activity of viral ribonucleoprotein (vRNP) complexes, thereby inhibiting viral RNA synthesis and assembly.