Destruction of Cholera Toxin Receptor on HeLa Cell Membrane Using Microbial Endoglycoceramidase

The sensitivity of HeLa cells to cholera toxin decreased byCorynebacteriumsp. endoglycoceramidase treatment. This endo-enzyme destroyed the cholera toxin receptor, ganglioside GM1, on the cell surface membrane by liberating intact oligosaccharide from it, which was confirmed by the decrease of intracellular cAMP accumulation and the results of the analysis of released oligosaccharide with a combination of pyridylamination method and HPLC. Fluorescence microscopy using the immunofluorescence method revealed that the amount of cholera toxin attached to the cells decreased in endoglycoceramidase-treated cells. The enzyme acted on cellular glycosphingolipids without addition of any activator protein which is required by other similar enzymes.Corynebacteriumendoglycoceramidase is a useful tool to elucidate the function of glycosphingolipids on the cell surfacein situ.