The mutant form of 3BP2-SH2 domain does not suppress FcεRI-mediated degranulation.

Control cells and cells expressing 3BP2-SH2 domain or the mutant form of 3BP2-SH2 domain (R486K) were stimulated with 10 ng/mL antigen. (A) Cell lysates were immunoprecipitated with anti–PLC-γ2 antibody. The immunoprecipitated proteins were separated by 10% SDS-PAGE and analyzed by immunoblotting with anti-pTyr mAb and anti–PLC-γ2. Similar results were obtained when the other lines were examined. (B) Analysis of β-hexosaminidase release. The antigen-induced releases are normalized by expression as a percentage of the total β-hexosaminidase activity. The results are the mean values ± SE from 3 independent experiments.