title: Evidence that a glycolipid tail anchors antigen 117 to the plasma membrane of Dictyostelium discoideum cells.
abstract: We describe the biochemical features of the putative cell cohesion molecule antigen 117, indicating that it is anchored to the plasma membrane by a glycolipid tail. Antigen 117 can be radiolabeled with [3H]myristate, [3H]palmitate, and [14C]ethanolamine. The fatty acid label is removed by periodate oxidation and nitrous acid deamination, indicating that the fatty acid is attached to the protein by a structure containing carbohydrate and an unsubstituted glucosamine. As cells develop aggregation competence, the antigen is released from the cell surface in a soluble form that can still be radiolabeled with [14C]ethanolamine but not with [3H]myristate or [3H]palmitate. The molecular weight of the released antigen is similar to that found in the plasma membrane, but it preferentially partitions in Triton X-114 as a hydrophilic, as opposed to a hydrophobic, protein. Plasma membranes contain the enzyme activity responsible for the release of the antigen in a soluble form.
authors.affiliation: E.A. Doisy Department of Biochemistry, St. Louis University School of Medicine, MO 63104.
authors.forename: H
authors.initials: H
authors.lastname: Sadeghi
authors.forename: A M
authors.initials: AM
authors.lastname: da Silva
authors.forename: C
authors.initials: C
authors.lastname: Klein
mesh_terms: D000954:Antigens, Surface / Q000494:pharmacology* / Q000633:toxicity; D001345:Autoradiography; D015815:Cell Adhesion Molecules; D002450:Cell Communication; D002462:Cell Membrane / Q000378:metabolism; D004023:Dictyostelium / Q000276:immunology / Q000378:metabolism* / Q000648:ultrastructure; D004591:Electrophoresis, Polyacrylamide Gel; D006017:Glycolipids / Q000378:metabolism*; D007118:Immunoassay; D008562:Membrane Glycoproteins / Q000378:metabolism*; D015800:Protozoan Proteins
chemical_list: D000954:Antigens, Surface; D015815:Cell Adhesion Molecules; D006017:Glycolipids; D008562:Membrane Glycoproteins; D015800:Protozoan Proteins; C052291:cell cohesion molecule, Dictyostelium