FIGURE 5.

The effect of RasGRP1 and RasGRP4 deficiency on FcϵRI-mediated proximal signaling. A, tyrosine phosphorylation of proteins. After sensitization with anti-DNP IgE, BMMCs were stimulated with DNP-HSA (100 ng/ml) for the indicated time points. Whole cell lysates were blotted with an anti-pTyr antibody and then reblotted with anti-LAT antisera. B, calcium flux. BMMCs were sensitized with anti-DNP IgE and then loaded with Fluo-4 AM. DNP-HSA was used to induce Ca²⁺ mobilization (top panel). For controls, ionomycin (1 μg/ml) was used (bottom panel). C, activation of PLCγ1, Syk, Erk, p38, and Jnk. WT and dKO cell lysates were blotted with antibodies against the phosphorylated and non-phosphorylated forms of PLCγ1, Syk, Erk, p38, and Jnk.