Hemagglutinin-neuraminidase protein of Newcastle disease virus (HN)

The **hemagglutinin-neuraminidase protein of Newcastle disease virus** (HN) is an oligomeric integral membrane glycoprotein found on the surface of NDV particles. It plays multiple essential roles during the viral life cycle: * **Attachment:** The HN binds to sialic acid-containing receptors on host cell surfaces, mediating initial attachment. * **Fusion activation:** It interacts with and activates the F (fusion) protein, triggering membrane fusion required for viral entry into cells. * **Neuraminidase activity:** The C-terminal domain possesses neuraminidase enzymatic function that cleaves sialic acids from cellular glycoconjugates. This prevents self-agglutination of virions and facilitates release from infected cells. * Structurally, it consists of an N-terminal transmembrane domain anchoring it to the envelope, a stalk region critical for F-protein interaction/activation specificity, and a globular neuraminidase "head" domain responsible for both receptor binding and enzymatic activity[1][3][5]. * Mutations within specific regions—especially within its stalk—can alter both fusogenicity/virulence by affecting F-protein activation or neuraminidase function[2]. The HN protein is considered a major target for antiviral strategies such as vaccine development due to its surface exposure and essential functions in infection.

Other names

HN proteinHemagglutinin-neuraminidase (NDV)NDV HNHemadsorbing-neuraminidase glycoprotein

For vaccines, immune response is generated against the HN antigen. For hypothetical inhibitors, mechanisms would include blocking receptor binding or neuraminidase activity.