Evidence for sulfate modification of H-2Dd on N-linked carbohydrate(s): possible involvement in Ly-49A interaction.
Murine class I molecules are ligands for Ly-49 molecules, a family of regulatory receptors expressed on murine NK cells. Since soluble sulfated mono- and polysaccharides interfere with the interaction of Ly-49A, a C-type lectin, and its class I ligand, Dd, it is possible that the oligosaccharides on class I molecules are sulfated and participate in Ly-49A binding. In this report, we show that H-2Dd expressed by activated T cells and various tumor cell lines is sulfated, as demonstrated by immunoprecipitation of Dd following Na235SO4 labeling. The 35SO4(-2) label on Dd expressed by a representative tumor cell, NZB1.1, is removed by peptide N-glycosidase F, but is resistant to endoglycosidase H treatment, indicating that the sulfate group is located on mature N-linked oligosaccharides. Two-dimensional SDS-PAGE analysis revealed that all major mature glycosylation variants of the Dd expressed by NZB1.1 are sulfated. Sodium chlorate, a potent inhibitor of ATP-sulfurylase, which prevents the formation of the sulfate donor, 3'-phosphoadenosine 5'-phosphosulfate, inhibited metabolic sulfation of Dd. NZB1.1 binds isolated Ly-49A immobilized on solid phase through an interaction by cell surface Dd, since cell adhesion was blocked by Abs directed against Dd or Ly-49A. Treatment of the Dd-expressing NZB1.1 tumor cells with sodium chlorate reduced their ability to bind immobilized Ly-49A, particularly when Ly-49A density was limiting. These results provide evidence for sulfation of H-2Dd oligosaccharide moieties, and suggest a role for this posttranslational modification in the interaction of Dd with Ly-49A.
Chang
C S
CS
Department of Medical Microbiology and Immunology, Faculty of Medicine, University of Alberta, Edmonton, Canada.
Kane
K P
KP
D000818:Animals; D000950:Antigens, Ly; D002241:Carbohydrates; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D006183:H-2 Antigens / Q000276:immunology* / Q000378:metabolism; D064532:Histocompatibility Antigen H-2D; D037181:Lectins, C-Type; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D011971:Receptors, Immunologic / Q000276:immunology / Q000378:metabolism; D055630:Receptors, NK Cell Lectin-Like; D013431:Sulfates; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D014407:Tumor Cells, Cultured
D000950:Antigens, Ly; D002241:Carbohydrates; D006183:H-2 Antigens; D064532:Histocompatibility Antigen H-2D; D037181:Lectins, C-Type; D008562:Membrane Glycoproteins; D011971:Receptors, Immunologic; D055630:Receptors, NK Cell Lectin-Like; D013431:Sulfates