IL-3 and GM-CSF induce the expression of the inositol trisphosphate receptor in K562 myeloblast cells

When treated with IL-3 plus GM-CSF, K562 myeloblast cells acquired the ability to mobilize nonmitochondrial stores of intracellular Ca²⁺ in response to added Ins(1,4,5) P₃. Untreated K562 cells are capable of sequestering intracellular Ca²⁺ but released none of this Ca²⁺ in response to Ins (1,4,5)P₃. Untreated K562 cells were shown to have no detectable specific [³H]Ins (1,4,5)P₃ binding sites and no InsP₃ receptor mRNA as assayed by Northern blot and PCR. However, following IL-3 and GM-CSF treatment, both a single class of low nM K_D Ins(1,4,5)P₃ binding site and a 10 kb InsP₃ receptor mRNA were detectable. The results suggest that IL-3 and GM-CSF regulate the expression of the Ins(1,4,5)P₃ receptor gene.