Human parainfluenza virus 3 fusion protein (HPIV-3 F) (HPIV-3 F)

The Human parainfluenza virus 3 (HPIV-3) fusion protein is a type I integral membrane glycoprotein essential for the virus's ability to infect host cells (UniProt: P06828). It mediates the fusion between the viral envelope and the host cell plasma membrane, a process that is triggered after the hemagglutinin-neuraminidase (HN) protein binds to sialic acid receptors (PubMed: 26136236). The F protein exists in a metastable pre-fusion state and undergoes a massive irreversible conformational change to a stable post-fusion state to drive membrane merging. HPIV-3 is a major cause of lower respiratory tract disease, including pneumonia and bronchiolitis, particularly in infants and immunocompromised patients (StatPearls: NBK534219). Because of its surface exposure and critical role in entry, the F protein is the primary target for neutralizing antibodies and the focus of vaccine and antiviral development (PubMed: 32433533). Experimental therapies include fusion-inhibitor peptides that mimic the heptad repeat regions and monoclonal antibodies that lock the protein in its pre-fusion configuration. Currently, there are no FDA-approved drugs or vaccines specifically targeting the HPIV-3 F protein, though several candidates are in various stages of clinical and preclinical investigation.

Other names

HPIV3 F proteinFusion glycoproteinF proteinParainfluenza virus 3 FF0 precursor

Inhibition of viral-host membrane fusion by stabilizing the pre-fusion conformation or blocking the six-helix bundle formation (PubMed: 26136236).