The polysialyltransferase ST8Sia II/STX: posttranslational processing and role of autopolysialylation in the polysialylation of neural cell adhesion molecule.

Polysialyltransferase ST8Sia II (STX) polysialylates all of the major isoforms of NCAM and facilitates neurite outgrowth.

The neural cell adhesion molecule (NCAM) has different isoforms due to different sizes in its polypeptide and plays a significant role in neural development. In neural development, the function of NCAM is modified by polysialylation catalyzed by two polysialyltransferases, ST8Sia II and ST8Sia IV. Previously, it was reported by others that ST8Sia II polysialylates only transmembrane isoforms of...

Molecular Dissection of the ST8Sia IV Polysialyltransferase: Distinct Domains Are Required for NCAM Recognition and Polysialylation*

Specific amino acids in the first fibronectin type III repeat of the neural cell adhesion molecule play a role in its recognition and polysialylation by the polysialyltransferase ST8Sia IV/PST.

Polysialic acid is an anti-adhesive protein modification that promotes cell migration and the plasticity of cell interactions. Because so few proteins carry polysialic acid, we hypothesized that polysialylation is a protein-specific event and that a specific polysialyltransferase-substrate interaction is the basis of this specificity. The major substrate for the polysialyltransferases is the ne...

Morphofunctional plasticity in the adult hypothalamus induces regulation of polysialic acid-neural cell adhesion molecule through changing activity and expression levels of polysialyltransferases.

Polysialic acid-neural cell adhesion molecule (PSA-NCAM) expression in the adult nervous system is restricted to regions retaining a capacity for morphological plasticity. For the female rat hypothalamoneurohypophysial system (HNS), we have previously shown that lactation induces a dramatic decrease in PSA-NCAM, while leaving the level of total NCAM protein unchanged. Here, we wanted to elucida...

Pharmacological Inhibition of polysialyltransferase ST8SiaII Modulates Tumour Cell Migration

Polysialic acid (polySia), an α-2,8-glycosidically linked polymer of sialic acid, is a developmentally regulated post-translational modification predominantly found on NCAM (neuronal cell adhesion molecule). Whilst high levels are expressed during development, peripheral adult organs do not express polySia-NCAM. However, tumours of neural crest-origin re-express polySia-NCAM: its occurrence cor...