Hydrophilic anchor-deficient Thy-1 is secreted by a class E mutant T lymphoma.
To investigate the mechanism of glycophospholipid anchoring of the surface antigen Thy-1, we have undertaken a comparative biosynthetic study using a wild-type Thy-1+ murine T lymphoma (BW5147) and a mutant T lymphoma (class E) that synthesizes Thy-1 but fails to express it on the plasma membrane. Labelling experiments with D-[2-3H]mannose demonstrate that, unlike the wild type, the mutant cells are secreting large amounts of Thy-1 and that the secreted molecules are hydrophilic. Moreover, unlike the wild type, they fail to incorporate [3H]palmitic acid into Thy-1. Both wild-type and mutant cells do incorporate labeled galactose and fucose into Thy-1. We conclude that the lack of surface expression of Thy-1 by this mutant results from the failure to add anchor components to Thy-1.
D000818:Animals; D000954:Antigens, Surface / Q000032:analysis*; D050260:Carbohydrate Metabolism; D006023:Glycoproteins / Q000378:metabolism*; D050356:Lipid Metabolism; D008223:Lymphoma / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D009363:Neoplasm Proteins / Q000378:metabolism; D010641:Phenotype; D011499:Protein Processing, Post-Translational; D013601:T-Lymphocytes; D018800:Thy-1 Antigens
D000954:Antigens, Surface; D006023:Glycoproteins; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D018800:Thy-1 Antigens