Insertion of ganglioside GM1 into rat glioma C6 cells renders them susceptible to growth inhibition by the B subunit of cholera toxin

Abstract

The B subunit of cholera toxin does not affect the growth of rat glioma C6 cells which are deficient of its receptor, ganglioside GM1. Insertion of ganglioside GM1 into the plasma membrane of C6 cells renders them susceptible to inhibition of DNA synthesis by the B subunit. Exposure of C6 cells to butyrate induces an elevation of ganglioside GM1 as measured by an increase in binding of iodinated cholera toxin and also results in an inhibition of DNA synthesis by the B subunit. The extent of inhibition of DNA synthesis correlated with the binding of B subunit and was independent of adenylate cyclase activation or increases in intracellular cAMP levels.