ST8 alpha-N-acetyl-neuraminide alpha-2,8-sialyltransferase 1 (ST8SIA1)

Abstract

The CMP-sialic acid: sialylα2-3Galβ1-4Glcβ1-O-Cer α2,8-sialyltransferase (ST8Sia I) is the key enzyme for the biosynthesis of b-series gangliosides. ST8Sia I catalyses the transfer of a sialic acid residue from CMP-sialic acid onto GM3 (Neu5Acα2-3Galβ1-4Glcβ1-O-Cer) to form GD3 (Neu5Acα2-8Neu5Acα2-3Galβ1-4Glcβ1-O-Cer). The product GD3 can be converted to GT3, and both compounds can be elongated by other monosaccharides (i.e., GalNAc, Gal, and sialic acid) to form the b- and c-series gangliosides. Gangliosides from b- and c-series are essentially found in developing tissues during embryogenesis, and mainly restricted to the nervous system in healthy adults (Yamashita et al. 1999). They are enriched in glycolipid-enriched microdomains where they play a key role in the modulation of signal transduction (Todeschini et al. 2008). Moreover, substantial evidences have demonstrated the implication of ST8Sia I and b- and c-series gangliosides in oncogenesis by mediating cell proliferation, migration, tumor growth, and angiogenesis (Bobowski et al. 2012).