Regulation of neural cell adhesion molecule polysialylation: Evidence for nontranscriptional control and sensitivity to an intracellular pool of calcium

The polysialic acid component of neuronal cell adhesion molecule (NCAM), acts as a temporally regulated modulator of certain cell interactions during development. Developmental regulation of polysialic acid (PSA) synthesis by ciliary ganglion motorneurons was found not to be reflected in levels of polysialytransferase-1 (PST) or sialytransferase-X (STX) mRNA. The calcium dependence of polysialytransferase activity within a cell-free assay has been documented, and results indicate that calcium shuttling can lead to rapid regulation of PSA synthesis within developing tissues.