LYN suppression abrogates PLCG2^R665W-mediated downstream activation. (A) Calcium flux induced by 3 μg/ml α-IgM stimulation was measured in PLCγ2^−/− DT40 expressing WT human PLCG2 or R665W mutant. The data represents AUC by 6 replicates. In the treatment settings, 1.0 μM ibrutinib was pretreated for 1 hour followed by washout; 0.1 μM dasatinib was used. *P < .05; ***P < .001; NS = P > .05. (B) Downstream signaling was accessed in PLCγ2^−/− DT40 expressing either WT human PLCγ2 or R665W mutant. Cells were treated with 0.5 μg/ml α-IgM; 1.0 μM ibrutinib was pretreated for 1 hour followed by washout; and 0.1 μM dasatinib was used.