title: Identification of a 40-kDa cell surface sialoglycoprotein with the characteristics of a major influenza C virus receptor in a Madin-Darby canine kidney cell line.
abstract: Infection of cells by influenza C virus is known to be initiated by virus attachment to cell surface glycoconjugates containing N-acetyl-9-O-acetylneuraminic acid. Using an in vitro virus binding assay, we have detected this carbohydrate on several glycoproteins of Madin-Darby canine kidney cells (type I), a polarized epithelial cell line permissive for infection with influenza C virus. Among these proteins, only one was found to be present to a significant extent on the cell surface. This protein, gp40, was characterized as an O-glycosylated (mucin-type) integral membrane protein of 40 kDa, which was predominantly localized on the apical plasma membrane of filter-grown cells. It is a major cell surface sialoglycoprotein in this cell line and was shown to be subject to constitutive and rapid endocytosis. Thus, this glycoprotein can mediate not only the binding of influenza C virus to the cell surface, but also its delivery to endosomes, where penetration occurs by membrane fusion. Other highly sialylated cell surface glycoproteins were also detected but did not mediate influenza C virus binding to a significant extent, indicating that only gp40 contains 9-O-acetylated sialic acids.
authors.affiliation: Institut für Virologie, Philipps-Universität Marburg, Federal Republic of Germany.
authors.forename: G
authors.initials: G
authors.lastname: Zimmer
authors.forename: H D
authors.initials: HD
authors.lastname: Klenk
authors.forename: G
authors.initials: G
authors.lastname: Herrler
mesh_terms: D000818:Animals; D002240:Carbohydrate Sequence; D002460:Cell Line; D016764:Cell Polarity; D004285:Dogs; D004705:Endocytosis; D009982:Gammainfluenzavirus / Q000378:metabolism*; D007668:Kidney / Q000166:cytology / Q000378:metabolism / Q000382:microbiology; D008561:Membrane Fusion; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D011991:Receptors, Virus / Q000378:metabolism* / Q000502:physiology; D012794:Sialic Acids / Q000378:metabolism; D012795:Sialoglycoproteins / Q000378:metabolism*
chemical_list: D008562:Membrane Glycoproteins; D011991:Receptors, Virus; D012794:Sialic Acids; D012795:Sialoglycoproteins; C025676:9-O-acetyl-N-acetylneuraminic acid