Biosynthesis of the neural cell adhesion molecule: characterization of polypeptide C.
The biosynthesis of the neural cell adhesion molecule (N-CAM) was studied in primary cultures of rat cerebral glial cells, cerebellar granule neurons, and skeletal muscle cells. The three cell types produced different N-CAM polypeptide patterns. Glial cells synthesized a 135,000 Mr polypeptide B and a 115,000 Mr polypeptide C, whereas neurons expressed a 200,000 Mr polypeptide A as well as polypeptide B. Skeletal muscle cells produced polypeptide B. The polypeptides synthesized by the three cell types were immunochemically identical. The membrane association of polypeptide C was investigated with methods that distinguish peripheral and integral membrane proteins. Polypeptide C was found to be a peripheral membrane protein, whereas polypeptides A and B were integral membrane proteins with cytoplasmic domains of approximately 50,000 and approximately 25,000 Mr, respectively. The affinity of the membrane binding of polypeptide C increased during postnatal development. The posttranslational modifications of polypeptide C were investigated in glial cell cultures, and it was found to be N-linked glycosylated and sulfated.
D000367:Age Factors; D000818:Animals; D000954:Antigens, Surface / Q000096:biosynthesis*; D001253:Astrocytes / Q000378:metabolism; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules; D002478:Cells, Cultured; D002531:Cerebellum / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D006023:Glycoproteins / Q000096:biosynthesis*; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000096:biosynthesis*; D008970:Molecular Weight; D009132:Muscles / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D051381:Rats; D013431:Sulfates / Q000378:metabolism; D014415:Tunicamycin / Q000494:pharmacology
D000954:Antigens, Surface; D015815:Cell Adhesion Molecules; D006023:Glycoproteins; D046911:Macromolecular Substances; D008565:Membrane Proteins; D013431:Sulfates; D014415:Tunicamycin