Polysialylation of NCAM1

Stable Identifier
Reaction [transition]
Homo sapiens
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NCAM in the developing brain is highly polysialylated and is referred as the embryonic form of NCAM. Polysialic acid is a developmentally regulated, anti-adhesive glycan with a linear homopolymer of alpha2,8-linked sialic acid units. They are mainly attached to the fifth and sixth N-glycosylation sites of the fifth Ig-like domain of NCAM. Polysialylation of NCAM is catalyzed by two polysialyltransferases, ST8Sia II (STX) and ST8Sia IV (PST), which belong to the family of six genes encoding alpha2,8-sialyltransferases. These enzymes add polysialic acid to NCAM N-glycans until it reaches a certain size (up to 200 sialic acid residues), where neither enzyme can interact with polysialylated N-glycans, and the polymerization of sialic acid is terminated.
Due to the structure with its chemical nature, polysialic acid can attenuate the interaction of NCAM with NCAM and other molecules in the same membrane (cis-interaction) or in another cell membrane (trans-interaction). During axonal growth the presence of polysialic acid along axons seems to prevent inappropriate synapse formation.
Literature References
PubMed ID Title Journal Year
16267048 Genetic ablation of polysialic acid causes severe neurodevelopmental defects rescued by deletion of the neural cell adhesion molecule

Marth, JD, Röckle, I, Hildebrandt, H, Mühlenhoff, M, Schertzinger, F, Seidenfaden, R, Conzelmann, S, Gerardy-Schahn, R, Weinhold, B

J Biol Chem 2005
18059411 Polysialic acid in the plasticity of the developing and adult vertebrate nervous system

Rutishauser, U

Nat Rev Neurosci 2008
12765789 Polysialyltransferases: major players in polysialic acid synthesis on the neural cell adhesion molecule

Fukuda, M, Angata, K

Biochimie 2003
Catalyst Activity

alpha-N-acetylneuraminate alpha-2,8-sialyltransferase activity of alpha 2-8 polysialyltransferases [Golgi membrane]

Orthologous Events
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