Figure 3. The ΔTK mutant of ErbB1 does not undergo nucleolin-mediated activation unless wild type ErbB1 is present.

HEK-293T cells were co-transfected with pEGFP-nucleolin-myc and the wild type ErbB1 or ΔTK ErbB1 deletion mutant or both expression vectors. Following 20 minutes starvation cells were treated with EGF (100 ng/ml) for 10 minutes. (A) Cell lysates were immunoblotted with monoclonal antibody anti PY20. As control cell lysates were immunoblotted with polyclonal antibody to ErbB1, or monoclonal antibody anti Myc as indicated. (B) Cell lysates were incubated with BS3 cross linker and immunoblotted with polyclonal antibody to ErbB1.