Carbohydrate recognition by a natural killer cell receptor, Ly-49C.
Ly-49 represents a family of type II transmembrane proteins containing C-type lectin domains. At least two members of the Ly-49 family, namely Ly-49A and Ly-49C, are expressed by distinct subsets of natural killer cells and bind to class I major histocompatibility complex antigens on the surface of target cells. In this report we have established that Ly-49C mediates carbohydrate recognition. The sulfated glycans fucoidan, lambda-carrageenan, and dextran sulfate were found to be potent inhibitors of Ly-49C-mediated cell adhesion, whereas other polysaccharides of similar size, charge, or sulfate content were noninhibitory. All of the polysaccharides which inhibited Ly-49C adhesion also blocked the binding of the antibody 5E6 to Ly-49C-expressing COS cells, confirming the direct protein-carbohydrate interaction. The enzymatic removal of specific carbohydrates from the target cell surface has shown that Ly-49C-mediated adhesion is not sialic acid-dependent, but is significantly decreased following fucosidase treatment. These results suggest an important role for carbohydrate recognition by natural killer cell receptors.
Brennan
J
J
Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada.
Takei
F
F
Wong
S
S
Mager
D L
DL
D000818:Animals; D000950:Antigens, Ly; D001667:Binding, Competitive; D050260:Carbohydrate Metabolism; D002448:Cell Adhesion; D002460:Cell Line; D006026:Glycoside Hydrolases / Q000378:metabolism; D007694:Killer Cells, Natural / Q000378:metabolism*; D037181:Lectins, C-Type; D008562:Membrane Glycoproteins / Q000378:metabolism*; D011971:Receptors, Immunologic / Q000378:metabolism*; D055630:Receptors, NK Cell Lectin-Like; D011994:Recombinant Proteins / Q000378:metabolism; D013431:Sulfates / Q000378:metabolism
D000950:Antigens, Ly; D037181:Lectins, C-Type; D008562:Membrane Glycoproteins; D011971:Receptors, Immunologic; D055630:Receptors, NK Cell Lectin-Like; D011994:Recombinant Proteins; D013431:Sulfates; D006026:Glycoside Hydrolases