WB of human T47D cells showing specific immunolabeling of the ~34k cdc2 phosphorylated at Tyr15 (Control). Treatment with EGF caused dephosphorylation of the Tyr15 on cdc2 (Lane 2). The phosphospecificity of this labeling is also shown in lane 3 and 4 (lambda-phosphatase: λ-Ptase). These blots are identical to the control except that they were incubated in ?-Ptase before being exposed to the Anti-Phospho-Tyr15 cdc2. The immunolabeling is completely eliminated by treatment with ?-Ptase?