Trans-activity of plasma membrane-associated ganglioside sialyltransferase in mammalian cells

VILCAES A.; TORRES DEMICHELIS V.A.; DANIOTTI, J.L.

AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC

Lugar: Bethesda; Año: 2011 vol. 286 p. 31437 - 31437

Gangliosides are acidic glycosphingolipids that contain sialicacid residues and are expressed in nearly all vertebrate cells.They are synthesized at the Golgi complex by a combination ofglycosyltransferase activities followed by vesicular delivery tothe plasma membrane, where they participate in a variety ofphysiological as well as pathological processes. Recently, a numberof enzymes of ganglioside anabolism and catabolism havebeen shown to be associated with the plasma membrane. In particular,it was observed that CMP-NeuAc:GM3 sialyltransferase(Sial-T2) is able to sialylate GM3 at the plasma membrane (ciscatalyticactivity). In this work, we demonstrated that plasmamembrane-integrated ecto-Sial-T2 also displays a trans-catalyticactivity at the cell surface of epithelial and melanoma cells.By using a highly sensitive enzyme-linked immunosorbent assaycombined with confocal fluorescence microscopy, we ob