Cytidine Monophosphate-N-Acetylneuraminic Acid Synthetase (CMAS)

N-Acylneuraminate Cytidylyltransferase catalyzes the activation of Neu5Ac to Cytidine 5-prime-monophosphate N-acetylneuraminic acid (CMP-Neu5Ac), which provides the substrate required for the addition of sialic acid. Sialic acids of cell surface glycoproteins and glycolipids play a pivotal role in the structure and function of animal tissues. The pattern of cell surface sialylation is highly regulated during embryonic development, and changes with stages of differentiation. Studies of a similar murine protein suggest that this protein localizes to the nucleus.the second nuclear localization signal of mouse Cmas was sufficient to mediate nuclear import. Arg199 and arg202 were involved in both nuclear transport and synthetase activity, but enzyme activity was independent of nuclear localization.