SHIP1 is phosphorylated in HEK-293 cells. HEK-293 cells were transfected with SHIP1, labeled with 32P, and stimulated with 100 μm Sp-cAMPS (Sp) for 15 min or 10 μm isoproterenol (Iso) for 5 min. The FLAG-tagged SHIP1 was immunoprecipitated from cell extracts, resolved on a SDS gel, and subjected to autoradiography. A, upper panel presents the autoradiograph showing the effect of Sp-cAMPS or isoproterenol on phosphorylation of SHIP1. The lower panel presents the amount of 32P incorporated into SHIP1 based on the integrated band intensity normalized for protein expression. The data are expressed as percentages of control (Ctr). *, p < 0.05 (n = 3). B, treating cells with Sp-cAMPS or isoproterenol stimulates the activity of immunopurified SHIP1. HEK-293 cells were transfected with SHIP1, and the cells were incubated with 100 μm Sp-cAMPS for 15 min or 10 μm isoproterenol for 5 min before lysis. Both Sp-cAMPS and isoproterenol significantly increased activity. ***, p < 0.001 (n = 6).