title: O-glycosylation as a sorting determinant for cell surface delivery in yeast.
abstract: Little is known about the mechanisms that determine localization of proteins to the plasma membrane in Saccharomyces cerevisiae. The length of the transmembrane domains and association of proteins with lipid rafts have been proposed to play a role in sorting to the cell surface. Here, we report that Fus1p, an O-glycosylated integral membrane protein involved in cell fusion during yeast mating, requires O-glycosylation for cell surface delivery. In cells lacking PMT4, encoding a mannosyltransferase involved in the initial step of O-glycosylation, Fus1p was not glycosylated and accumulated in late Golgi structures. A chimeric protein lacking O-glycosylation motif was missorted to the vacuole and accumulated in late Golgi in wild-type cells. Exocytosis of this protein could be restored by addition of a 33-amino acid portion of an O-glycosylated sequence from Fus1p. Our data suggest that O-glycosylation functions as a sorting determinant for cell surface delivery of Fus1p.
authors.affiliation: Max Planck Institute for Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.
authors.forename: Tomasz J
authors.initials: TJ
authors.lastname: Proszynski
authors.forename: Kai
authors.initials: K
authors.lastname: Simons
authors.forename: Michel
authors.initials: M
authors.lastname: Bagnat
mesh_terms: D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D015153:Blotting, Western; D002462:Cell Membrane / Q000378:metabolism*; D005089:Exocytosis; D005656:Fungal Proteins / Q000502:physiology*; D005838:Genotype; D006031:Glycosylation; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000378:metabolism; D008364:Mannosyltransferases / Q000378:metabolism; D008565:Membrane Proteins; D008856:Microscopy, Fluorescence; D018715:Microscopy, Video; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D013696:Temperature; D014415:Tunicamycin / Q000494:pharmacology
chemical_list: C490024:FUS1 protein, S cerevisiae; D005656:Fungal Proteins; D008164:Luminescent Proteins; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D014415:Tunicamycin; D049452:Green Fluorescent Proteins; D008364:Mannosyltransferases; C082696:protein O-mannosyltransferase