Effect of PP2 on antigen- and SCF-mediated protein phosphorylation in HuMCs, and antigen- and SCF-mediated NTAL phosphorylation in Lyn^–/– and Btk^–/– BMMCs. (A) Sensitized HuMCs were triggered via FcϵRI (NP-BSA, 100 ng/mL) or Kit (SCF, 100 ng/mL) for 60 seconds in the absence or presence of the indicated concentrations of PP2. The extracted proteins were then probed using phosphospecific antibodies, or for Syk as described in Figure 5B. (B-C) Sensitized BMMCs were triggered with (B) DNP-HSA (100 ng/mL) or (C) SCF (100 ng/mL) for 120 seconds, and proteins were extracted under nondenaturing conditions and immunoprecipitated with anti-NTAL mAb. The immunoprecipitates were then probed with antiphosphotyrosine and anti-NTAL mAbs. The gels were then scanned and the data initially normalized to NTAL loading and then calculated as a percentage of the W/T triggered responses. These data are presented in the bar charts. The blots are representative of up to 4 similar experiments and the bar charts are means ± SE of n = 4.