Human parainfluenza virus type 3 fusion glycoprotein (HPIV3 F)

The **human parainfluenza virus type 3 fusion glycoprotein** is an envelope-anchored viral surface protein essential for mediating the fusion of the viral and host cell membranes, a critical step for viral entry and initiation of infection[1][4][7]. It functions in close cooperation with the hemagglutinin-neuraminidase (HN) glycoprotein, which binds to host cell sialic acid residues and triggers the conformational activation of the F protein. The HPIV3 F glycoprotein is a Class I fusion protein that undergoes large structural rearrangements during the fusion process, transitioning from a metastable pre-fusion trimer to a post-fusion conformation[1][4][7]. This protein is a primary target for neutralizing antibodies and vaccine development, with potent monoclonal antibodies shown to confer protection in animal models[5][6]. No small-molecule drugs currently target the F protein with clinical approval[5][6]. As the main mediator of cell entry, it plays a central role in HPIV3 pathogenesis, particularly in pediatric, elderly, immunocompromised, and transplant patient populations[4][6].

Other names

HPIV3 F proteinParainfluenza virus 3 fusion proteinFusion (F) glycoprotein of human parainfluenza virus type 3

Neutralizing antibodies block conformational changes in F protein required for membrane fusion[5][6]; Fusion inhibitors (in research) may stabilize prefusion state or block cleavage/activation, thereby preventing fusion[5]; Monoclonal antibodies may target either the pre-fusion or post-fusion conformations to block infection[6]