ST8SIA3
Function
Catalyzes the transfer of sialic acid from a CMP-linked sialic acid donor onto a terminal alpha-2,3-, alpha-2,6-, or alpha-2,8-linked sialic acid of an acceptor, such as N-linked oligosaccharides of glycoproteins and glycolipids through alpha-2,8-linkages (PubMed:10766765, PubMed:26192331, PubMed:9826427). Forms oligosialic and polysialic acid on various sialylated N-acetyllactosamine oligosaccharides of glycoproteins, including FETUB N-glycans, a2-HS-glycoprotein (AHSG) and alpha 2,3-sialylated glycosphingolipids, such as alpha 2,3-sialylparagloboside and ganglioside GM3 and to a lesser extent NCAM1 N-glycans (PubMed:10766765, PubMed:9826427). However, it is much more specific to N-linked oligosaccharides of glycoproteins than glycosphingolipids (By similarity). 2,3-sialylparagloboside serves as the best acceptor substrate among the glycolipids (By similarity). alpha-Neu5Ac-(2->8)-alpha-Neu5Ac-(2->3)-beta-D-Gal-(1->4)-6S-D-GlcNAc and monosialyl and disialyl N-acetyllactosamines are the best acceptor substrates among glycoproteins (PubMed:10766765, PubMed:26192331). May plays critical role in the striatum by mediating the formation of disialylated and trisialylated terminal glycotopes on N- and O-glycans of specific striatal proteins, regulating their distribution in lipid rafts, affecting their interaction with other binding partners, and subsequently modulating striatal functions (By similarity).
Pathway
Protein modification; protein glycosylation.
Post-translational modifications
Autopolysialylated.
Sequence Similarities
Belongs to the glycosyltransferase 29 family.
Tissue Specificity
Expressed in fetal and adult brain and fetal liver.
Cellular localization
- Golgi apparatus membrane
- Single-pass type II membrane protein
Alternative names
SIAT8C, ST8SIA3, Ganglioside GD3 synthase ST8SIA3, Sialyltransferase 8C, Sialyltransferase St8Sia III, hST8Sia III, SIAT8-C, ST8SiaIII