Bombesin stimulation of inositol 1,4,5-trisphosphate generation and intracellular calcium release is amplified in a cell line overexpressing the N-ras proto-oncogene.

Bombesin stimulation of T15 cells in which the inducible N-ras oncogene is overexpressed caused elevated production of inositol phosphates compared to uninduced cells [Wakelam, Davies, Houslay, McKay, Marshall & Hall (1986) Nature (London) 323, 173-176]. This elevated response is shown here to result from increased generation of inositol 1,4,5-trisphosphate leading to an elevated release of intracellular stored Ca2+. Single-cell analysis of Ca2+ release showed that the elevated response is not a consequence of an increased fraction of responding cells. These amplifications are consistent with p21N-ras acting like a guanine nucleotide coupling protein in this cell line.