Sialyltransferase activity in FR3T3 cells transformed with ras oncogene: decreased CMP-Neu5Ac:Gal beta 1-3GalNAc alpha-2,3-sialyltransferase.
We have investigated the activity of CMP-Neu5Ac:Gal beta 1-3GalNAc alpha-2,3-sialyltransferase (EC 2.4.99.4) in FR3T3 cells transformed by the Ha-ras oncogene in which we have previously demonstrated the higher expression of the beta-galactosidase alpha-2,6-sialyltransferase (EC 2.4.99.1) [21]. We demonstrate that the presence of the activated ras gene decreases the activity of this specific alpha-2,3-sialyltransferase fourfold. According to the kinetic parameters and to mixing experiments, we can assume that this decreased enzymatic activity reflects a decrease in the number of active O-glycan alpha-2,3-sialyltransferase polypeptides in ras-transformed cells. However, no change in the binding of Peanut agglutinin was observed on the cell surface of ras-transformed FR3T3 suggesting that no change in the sialylation of O-glycan core 1 appeared in these cells, although the activity of the alpha-2,3-sialyltransferase was decreased.
Delannoy
P
P
Laboratoire de Chimie Biologique (Unité Mixte de Recherche du CNRS n. 111), Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France.
Pelczar
H
H
Vandamme
V
V
Verbert
A
A
D000818:Animals; D010367:Arachis / Q000378:metabolism; D002240:Carbohydrate Sequence; D002461:Cell Line, Transformed; D002471:Cell Transformation, Neoplastic / Q000378:metabolism*; D005347:Fibroblasts / Q000201:enzymology; D015870:Gene Expression; D011905:Genes, ras; D037102:Lectins / Q000378:metabolism; D008969:Molecular Sequence Data; D019887:Peanut Agglutinin; D037121:Plant Lectins; D051381:Rats; D012799:Sialyltransferases / Q000378:metabolism*; D000094663:beta-Galactoside alpha-2,3-Sialyltransferase
D037102:Lectins; D019887:Peanut Agglutinin; D037121:Plant Lectins; D012799:Sialyltransferases; D000094663:beta-Galactoside alpha-2,3-Sialyltransferase