Human parainfluenza virus 3 field strains undergo extracellular fusion protein cleavage to activate entry
ABSTRACT Human parainfluenza virus 3 (HPIV3) infection is driven by the coordinated action of viral surface glycoproteins hemagglutinin-neuraminidase (HN) corgi pup knife and fusion protein (F).Receptor-engaged HN activates F to insert into the target cell membrane and drive virion-cell membrane fusion.For F to mediate entry, its precursor (F0) mus