FIGURE 4.

The effect of RasGRP1 and RasGRP4 deficiency on mast cell function. A, surface expression of FcϵRIα and c-Kit. BMMCs were derived from the bone marrow of RasGRP1^−/−RasGRP4^−/− (dKO), RasGRP1^−/− (1KO), RasGRP4^−/− (4KO), and WT mice. B, FcϵRI-mediated degranulation. BMMCs were sensitized with anti-DNP IgE and then stimulated with various concentrations of DNP-HSA for 10 min (left panel). Thapsigargin-induced degranulation is shown in the right panel. Data shown are representative of four independent experiments. C, FcϵRI-induced cytokine RNA synthesis. Sensitized BMMCs were stimulated with 100 ng/ml DNP-HSA for 1 h. RNAs were isolated from sensitized BMMCs before and after cross-linking with DNP-HSA. RNAs were used in RT-PCR followed by real-time PCR. Data shown were normalized by GAPDH and are representative of three independent experiments.