Characterization of soluble forms of NCAM.
Neural cell adhesion molecule (NCAM) has been described as a family of membrane glycoproteins. However, soluble NCAM immunoreactivity has long been recognized. We here show that soluble NCAM is composed of two quantitatively major polypeptides of Mr 180,000 and 115,000 and two minor components of Mr 160,000 and 145,000. Soluble NCAM was immunochemically identical to membrane NCAM, was polysialylated and carried the HNK-1 epitope. It only constituted 0.8% of total NCAM in newborn rat brain. Soluble NCAM appeared in neuronal cell culture medium 15-30 min after the start of synthesis preceding accumulation of membrane-associated NCAM on the cell surface. This indicates that soluble NCAM contains a secreted component.
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism; D000911:Antibodies, Monoclonal / Q000032:analysis; D000954:Antigens, Surface / Q000032:analysis* / Q000235:genetics / Q000276:immunology; D001923:Brain Chemistry; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules; D002462:Cell Membrane / Q000032:analysis; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000032:analysis; D007163:Immunosorbent Techniques; D009474:Neurons / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D012794:Sialic Acids / Q000032:analysis; D012995:Solubility
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D015815:Cell Adhesion Molecules; D000939:Epitopes; D012333:RNA, Messenger; D012794:Sialic Acids; C021319:polysialic acid