Delayed extinction of G-CSF–induced Akt activation in ▵716 cells.

Ba/F3 cells transfected with the Δ716 G-CSFR were grown in RPMI 1640 medium containing 10% FBS and 2 mmol/L glutamine, supplemented with either 10% WEHI-CM (source of IL-3) or 1.9 ng/mL G-CSF for 10 days. The cells were washed twice, then transferred to media devoid of serum and cytokines. At the indicated time points, the cells were lysed, immunoprecipitated with anti-Akt, and subjected to Akt in vitro kinase assays. Data are expressed as the ratio of histone H2B phosphorylation in Akt immunoprecipitates compared with control lysates immunoprecipitated with normal sheep IgG. A linear representation of the data is shown in the inset.