ST8SIA1
Function
Catalyzes the addition of sialic acid in alpha 2,8-linkage to the sialic acid moiety of the ganglioside GM3 to form ganglioside GD3; gangliosides are a subfamily of complex glycosphingolipds that contain one or more residues of sialic acid (PubMed:18348864, PubMed:22885356, PubMed:7937974, PubMed:8058740, PubMed:8195250, PubMed:8631981, PubMed:8706663). Can catalyze the addition of a second alpha-2,8-sialic acid to GD3 to form GT3 (PubMed:8631981). Can use GM1b, GD1a and GT1b as acceptor substrates to synthesize GD1c, GT1a and GQ1b respectively (PubMed:8706663). Can synthesize unusual tetra- and pentasialylated lactosylceramide derivatives identified as GQ3 (II3Neu5Ac4-Gg2Cer) and GP3 (II3Neu5Ac5-Gg2Cer) in breast cancer cells (PubMed:22885356).
Pathway
Protein modification; protein glycosylation.
Lipid metabolism; sphingolipid metabolism.
Sequence Similarities
Belongs to the glycosyltransferase 29 family.
Tissue Specificity
Strongly expressed in melanoma cell lines, adult and fetal brain and to a lesser extent in adult and fetal lung.
Cellular localization
- Golgi apparatus membrane
- Single-pass type II membrane protein
Alternative names
SIAT8, SIAT8A, ST8SIA1, Ganglioside GD3 synthase, Ganglioside GT3 synthase, Sialyltransferase 8A, Sialyltransferase St8Sia I, SIAT8-A, ST8SiaI