title: Blood group-active carbohydrate chains on the receptor for epidermal growth factor of A431 cells.
abstract: The antigens expressed on the carbohydrate chains of the receptor for epidermal growth factor of A431 cells were studied by immunoblotting with monoclonal antibodies. Blood group A and the Type 1 based blood group ALeb and Lea antigens were detected as well as antigens associated with unsubstituted, monofucosylated and difucosylated Type 2 blood group chains. The Lea and the difucosylated Type 2 antigen activities were abolished by treating the blotted receptor with endo-beta-galactosidase, indicating that they are expressed on backbone structures of poly-lacto/neolacto type. (The term 'poly-lacto/neolacto' is used here to describe oligosaccharide backbone structures consisting of repeating Type 1, Gal beta 1-3GlcNAc (lacto) or Type 2, Gal beta 1-4GlcNAc (neolacto) sequences.) The glycosidic linkage of oligosaccharides to protein was investigated using Pronase digests of the receptor biosynthetically labelled with [3H]glucosamine or [3H]fucose. The oligosaccharides were alkali-resistant, consistent with N- rather than O-glycosidically linked chains. A proportion of [3H]fucose-labelled glycopeptides was susceptible to endo-beta-galactosidase, confirming the immunoblotting experiment using antibodies against the Lea and the difucosylated Type 2 antigenic determinants. Oligosaccharides were released from the [3H]fucose- and [3H]-glucosamine-labelled glycopeptides by hydrazinolysis. Chromatography of the oligosaccharides on Bio-Gel P6 and Concanavalin A columns indicated a spectrum of oligosaccharides which include those of high mannose type labelled with [3H]glucosamine, and a mixture of oligosaccharides labelled with [3H]fucose and [3H]glucosamine of bi- and multiantennary complex types of which a subpopulation is susceptible to digestion with endo-beta-galactosidase.
mesh_terms: D000017:ABO Blood-Group System / Q000276:immunology*; D000818:Animals; D002240:Carbohydrate Sequence; D002294:Carcinoma, Squamous Cell / Q000032:analysis*; D002460:Cell Line; D066246:ErbB Receptors; D005643:Fucose / Q000378:metabolism; D005944:Glucosamine / Q000378:metabolism; D006801:Humans; D051379:Mice; D008970:Molecular Weight; D009439:Neuraminidase / Q000378:metabolism; D009844:Oligosaccharides / Q000276:immunology*; D011956:Receptors, Cell Surface / Q000032:analysis*
chemical_list: D000017:ABO Blood-Group System; D009844:Oligosaccharides; D011956:Receptors, Cell Surface; D005643:Fucose; D066246:ErbB Receptors; D009439:Neuraminidase; D005944:Glucosamine