Biosynthesis of the Neural Cell Adhesion Molecule: Characterization of Polypeptide C

• Published in: The Journal of cell biology 1985-12, Vol.101 (6), p.2310-2315
• Main Authors: Nybroe, Ole, Albrechtsen, Merete, Dahlin, Jan, Linnemann, Dorte, Lyles, Joan M., Møller, Claus J., Bock, Elisabeth
• Format: Article
• Language: English
• Subjects: Age Factors; Animals; Antigens, Surface - biosynthesis; Astrocytes; Astrocytes - metabolism; Biological and medical sciences; Cell Adhesion; Cell Adhesion Molecules; Cell culture techniques; Cell interactions, adhesion; Cells; Cells, Cultured; Cerebellum - metabolism; Cultured cells; Cytoplasm - metabolism; Fundamental and applied biological sciences. Psychology; Glycoproteins - biosynthesis; Macromolecular Substances; Membrane proteins; Membrane Proteins - biosynthesis; Microsomes; Molecular and cellular biology; Molecular Weight; Muscles - metabolism; Neural cell adhesion molecules; Neuroglia; Neurons; P branes; Protein Processing, Post-Translational - drug effects; Rats; Sulfates - metabolism; Tunicamycin - pharmacology
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.101.6.2310

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 Mrpolypeptide B and a 115,000 Mrpolypeptide C, whereas neurons expressed a 200,000 Mrpolypeptide 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 ∼50,000 and ∼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.