FIGURE 5.

Downstream FcεRI signal transduction is largely intact in WeeB BMMCs. BMMCs were sensitized with IgE overnight and stimulated with 100 ng/ml DNP₂₁-BSA for the indicated periods. A, Membrane proximal phosphorylation events were analyzed by immunoblotting using antisera to phospho-LAT (Tyr¹⁹¹), phospho-PLC-γ2 (Tyr¹²¹⁷), and phospho-Akt1 (Ser⁴⁷³). Blots were subsequently stripped and reprobed using antibodies to LAT, PLC-γ2, and Akt1. B, MAPK phosphorylation events were analyzed as in A using the indicated antibodies. C, Ca²⁺ flux was measured using BMMCs loaded with Indo 1-AM and stimulated with the indicated concentrations of Ag, followed by the addition of 1 μg/ml ionomycin. D, A panel of phosphospecific antisera were used to probe lysates derived from BMMCs stimulated with 20 μg/ml anti-IgE. In cases where phospho-specific antisera were not effectively stripped from membranes, duplicate samples from the same lysate were run on separate gels. Results are representative of three independent experiments.