Cholera toxin effects on cell growth accompanied by selective alterations in metabolite uptake and modification of cell surface proteins
Rieber, M.; Bacalao, J.; Alonso, G.
Cancer Research 35(11 Part 1): 3009-3013
1975
ISSN/ISBN: 0008-5472 PMID: 1182696 Document Number: 89964
Exposure of Chinese hamster ovary cells to cholera toxin at or below mug levels causes a marked morphological changes and increased adhesion and orientation of the cells. Such changes are paralleled by alterations in surface proteins as indicated by the cholera toxin-mediated modifications detectable by lactoperoxidase-catalyzed radioiodination of outer proteins. Mild tryptic treatment of cells prelabeled with [3H]glucosamine revealed a different kinetics of release of external glycoproteins in cells exposed to the toxin. An alteration in a specific glycoprotein species in cholera toxin-treated cells became evident by polyacrylamide gel electrophoresis followed by fluorography of 3H-labeled cellular glycoproteins. The effects of cholera toxin on surface proteins and growth of the cells occurred in the absence of a modification in amino acid uptake or incorporation of precursors into protein. However, thymidine uptake and glucosamine incorporation were inversely affected to toxin treatment. Some of the effects of the toxin appeared to be antagonized by colchicine.