title: The roles of individual cysteine residues of Sendai virus fusion protein in intracellular transport.
abstract: The role of intramolecular disulfide bonds in the fusion (F) protein of Sendai virus was studied. The 10 cysteine residues were changed to serine residues using site-directed mutagenesis. None of the cysteine mutant F proteins reacted with a monoclonal antibody specific for the mature conformation of the F protein, but eight of ten mutants reacted with an immature conformation-specific monoclonal antibody. The transport of these mutant proteins to the cell surface was drastically reduced. All of the cysteine mutant F proteins remained sensitive to endoglycosidase H (endo H) for 3 h after their synthesis. Moreover, cell surface transport of the hemagglutinin-neuraminidase (HN) protein co-expressed with each of these cysteine mutant F proteins was also reduced. These results suggest that all cysteine residues participate in the formation of intramolecular disulfide bonds, that co-translational disulfide bond formation is crucial to the correct folding and intracellular transport of the F protein, and that interaction of the F and HN proteins takes place intracellulary.
authors.affiliation: Department of Bioscience and Technology, Faculty of Agriculture, Iwate University, Morioka, 020-8550, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Segawa
authors.forename: M
authors.initials: M
authors.lastname: Kato
authors.forename: T
authors.initials: T
authors.lastname: Yamashita
authors.forename: H
authors.initials: H
authors.lastname: Taira
mesh_terms: D000818:Animals; D001692:Biological Transport; D019556:COS Cells; D003545:Cysteine; D018108:Respirovirus / Q000737:chemistry / Q000502:physiology*; D014760:Viral Fusion Proteins / Q000502:physiology*; D014779:Virus Replication
chemical_list: D014760:Viral Fusion Proteins; D003545:Cysteine