Sulfation and phosphorylation of the neural cell adhesion molecule, N-CAM

Embryonic chicken brain tissue cultured in media containing 35S-labeled sulfate or 32P-labeled phosphate incorporated 35S or 32P into the neural cell adhesion molecule (N-CAM). The 35S label was located in asparagine-linked carbohydrates on both glycopeptides (molecular weights, 170,000 and 140,000) but not in the sialic acid. The 32P label was detected in phosphoamino acids in the carboxyl-terminal third of both polypeptides, but the ratio of phosphoserine to phosphothreonine differed in the two species. The sulfated saccharides and phosphoamino acids may provide additional sites for functional control of N-CAM.