Interleukin 3‐stimulated proliferation is sensitive to pertussis toxin: Evidence for a guanyl nucleotide regulatory protein‐mediated signal transduction mechanism

Interleukin 3 (IL‐3) stimulates several biochemical and biological responses in IL‐3‐dependent tissue culture cells. We examined the possibility that guanyl nucleotide regulatory (G) proteins may transduce signals from IL‐3 receptors. We report here that pertussis toxin (PT), which can covalently modify a subclass of G proteins, is capable of inhibiting IL‐3‐stimulated proliferation in a dose‐dependent fashion. PT inhibiton of IL‐3‐stimulated proliferation could be overcome by using the Ca^{+ +} ionophore A23187 in conjunction with TPA. PT could also inhibit IL‐3‐stimulated hexose transport. In the absence of IL‐3, hexose transport could be stimulated by introducing GTPγS into intact cells. From these data we propose that IL‐3 receptors transduce signals via a PT‐sensitive G protein(s).