title: Cell surface anchorage and ligand-binding domains of the Saccharomyces cerevisiae cell adhesion protein alpha-agglutinin, a member of the immunoglobulin superfamily.
abstract: alpha-Agglutinin is a cell adhesion glycoprotein expressed on the cell wall of Saccharomyces cerevisiae alpha cells. Binding of alpha-agglutinin to its ligand a-agglutinin, expressed by a cells, mediates cell-cell contact during mating. Analysis of truncations of the 650-amino-acid alpha-agglutinin structural gene AG alpha 1 delineated functional domains of alpha-agglutinin. Removal of the C-terminal hydrophobic sequence allowed efficient secretion of the protein and loss of cell surface attachment. This cell surface anchorage domain was necessary for linkage to a glycosyl phosphatidylinositol anchor. A construct expressing the N-terminal 350 amino acid residues retained full a-agglutinin-binding activity, localizing the binding domain to the N-terminal portion of alpha-agglutinin. A 278-residue N-terminal peptide was inactive; therefore, the binding domain includes residues between 278 and 350. The segment of alpha-agglutinin between amino acid residues 217 and 308 showed significant structural and sequence similarity to a consensus sequence for immunoglobulin superfamily variable-type domains. The similarity of the alpha-agglutinin-binding domain to mammalian cell adhesion proteins suggests that this structure is a highly conserved feature of adhesion proteins in diverse eukaryotes.
authors.affiliation: Department of Biological Sciences, Hunter College, City University of New York, New York 10021.
authors.forename: D
authors.initials: D
authors.lastname: Wojciechowicz
authors.forename: C F
authors.initials: CF
authors.lastname: Lu
authors.forename: J
authors.initials: J
authors.lastname: Kurjan
authors.forename: P N
authors.initials: PN
authors.lastname: Lipke
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D016384:Consensus Sequence; D004252:DNA Mutational Analysis; D005656:Fungal Proteins / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism; D006031:Glycosylation; D007136:Immunoglobulins / Q000737:chemistry; D007294:Inositol / Q000378:metabolism; D008024:Ligands; D000072235:Mating Factor; D008969:Molecular Sequence Data; D010168:Palmitates / Q000378:metabolism; D010455:Peptides / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D012441:Saccharomyces cerevisiae / Q000166:cytology*; D016415:Sequence Alignment; D017384:Sequence Deletion; D012995:Solubility; D013329:Structure-Activity Relationship
chemical_list: D015815:Cell Adhesion Molecules; D005656:Fungal Proteins; D006023:Glycoproteins; D007136:Immunoglobulins; D008024:Ligands; D010168:Palmitates; D010455:Peptides; D007294:Inositol; D000072235:Mating Factor