IgE-induced adhesion of BMMCs to FN requires PI3K but not Erk or p38. (A) Adhesion of normal BMMCs to FN in response to 1 μg/mL IgE or 5 ng/mL SF in the presence of the indicated concentrations of LY294002 (LY) following a 30-minute adhesion assay. All wells contained the same level of DMSO (vehicle for LY). Adhesion was significantly (P < .05) different between control stimulated and stimulated + LY294002-treated samples. (B) Adhesion of SHIP^+/+ (□) and ^–/– (▪) BMMCs to FN following a 60-minute exposure to the indicated concentrations of IgE or SF. Adhesion was significantly (P < .05) different between SHIP^+/+ and ^–/– levels except for the control, 0.1 and 5 μg/mL values. (C) A time course of the adhesion of SHIP^+/+ (□) and ^–/– (▪) BMMCs to FN in the presence of 1 μg/mL IgE and, for comparison, a 60-minute exposure to 0.5 ng/mL SF. Adhesion was significantly (P < .05) different between SHIP^+/+ and ^–/– values. (D) Adhesion of normal BMMCs to FN for 30 minutes in the presence of 1 μg/mL IgE (□) or 2 ng/mL SF (▪) in the absence (C) or presence of 1 μM U0126, 20 μM PD98059 (PD), or 10 μM SB203580 (SB). All wells contained the same level of DMSO (vehicle for the inhibitors). Adhesion was not significantly different between IgE- and IgE + U0126-, PD98059-, or SB203 580-stimulated samples. Results shown are the mean ± SEM of triplicate determinations. Background adhesion was subtracted from the values graphed in (A, 14%), (C, 4%-11%), and (D, 5%-11%). Similar results were obtained in 4 (A), 5 (B), 3 (C), and 3 (D) separate experiments.