Parainfluenza virus type 3 hemagglutinin-neuraminidase protein (HN protein)

The Parainfluenza virus type 3 hemagglutinin-neuraminidase protein (HN protein) is a multifunctional envelope glycoprotein that plays a central role in the infectivity of human parainfluenza virus type 3 (HPIV-3). It mediates both the attachment of the virus to the host cell via recognition and binding of sialic acid-containing receptors (hemagglutination activity) and the cleavage of sialic acid residues from glycoproteins (neuraminidase activity), which is important for the release of newly formed viral particles[2][3][5]. The HN protein also activates the viral fusion protein (F), facilitating fusion between the viral envelope and host cell membrane—a key step in viral entry and infection[4]. Structurally, HN is a membrane-associated protein, with a prominent hydrophobic region that allows insertion into the viral envelope, and contains several sites of N-glycosylation[2][3]. Its antigenic features are targets for neutralizing antibodies, and sequence variation in HN can affect both immune recognition and susceptibility to neuraminidase inhibitors or monoclonal antibodies[1][4].

Other names

HN glycoproteinHemagglutinin-neuraminidase protein (Parainfluenza virus type 3)HPIV-3 HN

Competitive inhibition of neuraminidase activity, preventing cleavage of sialic acid, thus inhibiting viral spread and release