PMA induces dephosphorylation of CBL in mouse macrophage cell line (J774A.1) stimulated with sensitized sheep RBC. CBL immunoprecipitation was done in J774A.1 cells stimulated with sensitized (IgG coated) sheep RBCs at 37°C in a time dependent manner. Anti-phosphotyrosine blot showing CBL immunoprecipitation. Lane 1, preimmune and lane 2, resting condition (NS). Lane 3, 4 & 5, cells were stimulated with sensitized sheep RBCs for 1, 5 and 10 min. Lane 6, 7 & 8, preincubated with PMA (200 ng/ml) for 5 min. at 37°C followed by FcγR stimulation for 1, 5 and 10 min. respectively.