The stimulation of inositol phosphate generation in NIH-3T3 cells and a derived transformant overexpressing the p21N-ras gene (T15+ cells) was examined. Incubation with NaF in the presence of Al3+ leads to the generation of inositol phosphates in each cell type, though the response in the T15+ cells is significantly amplified. The effect of fluoroaluminate is dose- and time-dependent. No differences were observed in fluoroaluminate-stimulated cyclic AMP accumulation among the cell types. In another NIH-3T3-derived cell line that expresses the transforming lys61 mutant of N-ras, no amplification of fluoroaluminate-stimulated inositol phosphate generation is observed. These results provide support for the proposal that, in the T15 cell line, p21N-ras can act in a guanine nucleotide-binding regulatory protein (G-protein)-like manner.

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