Hemagglutinin-neuraminidase glycoprotein (HN)

The Hemagglutinin-neuraminidase (HN) glycoprotein is a multifunctional type II integral membrane protein found on the surface of viruses in the Paramyxoviridae family, such as human parainfluenza viruses (HPIV) and mumps virus (Crennell et al., 2000, PNAS). It is important to note that the term 'Influenza hemagglutinin-neuraminidase' is technically a misnomer, as influenza viruses (Orthomyxoviridae) possess separate hemagglutinin (HA) and neuraminidase (NA) proteins, whereas paramyxoviruses combine these functions into the single HN protein (Lamb & Parks, 2013, Fields Virology). The HN protein is responsible for three primary activities: binding to sialic acid-containing receptors on host cells, promoting membrane fusion in conjunction with the fusion (F) protein, and acting as a neuraminidase to remove sialic acid from progeny virions to prevent self-aggregation (Moscona, 2005, Drug Discovery Today). As a critical component of the viral life cycle, HN is a major target for the development of antiviral drugs and vaccines. Therapeutic strategies often focus on inhibiting its neuraminidase activity or blocking its ability to bind to host cell receptors, with agents like DAS181 (Fludase) showing broad-spectrum activity against HPIV by enzymatically removing the sialic acid receptors themselves (Triana-Baltzer et al., 2009, Antiviral Research). Challenges in targeting HN include the high rate of viral mutation leading to antigenic drift and the potential for drug resistance (UniProt P04850).

Other names

HN proteinHemagglutinin-neuraminidaseHPIV HNViral attachment protein

Inhibition of viral neuraminidase activity and blockade of sialic acid receptor binding sites to prevent viral entry and release.