Tyrosine phosphorylation of PLC-γ2 by engagement of CD43. MO7e cells cross-linked with anti-CD43 MoAb (clone DF-T1) were incubated for the indicated time periods at 37°C. Cells treated with isotype-matched control IgG and goat antimouse IgG were incubated for 10 minutes at 37°C (Lane C). Cell lysates were immunoprecipitated with anti-PLC–γ2 Ab. Upper panel: these immunoprecipitates were separated by 7.5% SDS-PAGE and immunoblotted with antiphosphotyrosin MoAb; lower panel: the same membrane was reprobed with anti-PLC–γ2 Ab. These are the representative results from three separate experiments.