Evidence for the presence of N-CAM 180 on astrocytes from rat cerebellum and differences in glycan structures between N-CAM 120 and N-CAM 140.
Differences in the N-linked oligosaccharides on isoforms of the neural cell adhesion molecule (N-CAM) on astrocytes were found using a lectin, namely, Datura stramonium agglutinin (DSA). Integral proteins of astrocytes prepared from newborn rat cerebella were solubilized with Nonident P-40 and then separated into two fractions, an unbound fraction and a bound fraction, by a DSA-agarose column. Both fractions thus obtained were subjected to immunoblotting using an anti-N-CAM monoclonal antibody. In the DSA-bound fraction, N-CAM 180 was found as well as N-CAM 120 and N-CAM 140. On the other hand, N-CAM 180 was not detected in the unbound fraction, whereas N-CAM 120 and N-CAM 140 were. Furthermore, N-CAM 180 did not carry the HNK-1 epitope, whereas the other two isoforms did. Although the presence of N-CAM 180 on astrocytes was controversial until recently, the results shown here indicate that N-CAM 180 exists on rat astrocytes and exclusively carries a glycan structure reacting with DSA. This is the first demonstration of the production of N-CAM glycoforms carrying different oligosaccharides by a homogeneous astrocyte preparation. These results suggest that the glycosylation of each N-CAM isoform might be regulated independently. Whether each N-CAM with different glycans participates in different functions remains to be established.
Sasaki
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Department of Glycobiology, Tokyo Metropolitan Institute of Gerontology, Sakaecho, Itabashi-ku, Tokyo, Japan.
Endo
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D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D018959:CD57 Antigens / Q000032:analysis; D002531:Cerebellum / Q000378:metabolism*; D004587:Electrophoresis, Agar Gel; D006801:Humans; D015151:Immunoblotting; D037102:Lectins; D019006:Neural Cell Adhesion Molecules / Q000737:chemistry* / Q000378:metabolism*; D037121:Plant Lectins; D011134:Polysaccharides / Q000737:chemistry*; D011233:Precipitin Tests; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D012995:Solubility
D018959:CD57 Antigens; C041384:Datura stramonium lectin; D037102:Lectins; D019006:Neural Cell Adhesion Molecules; D037121:Plant Lectins; D011134:Polysaccharides; D020033:Protein Isoforms