Figure 3: Sos1-GRB2 coimmunoprecipitation. (a) Binding of GRB2 to Sos1 was recorded in all EqS cell lines; the complex was coimmunoprecipitated in higher amount in EqS02aE5 and EqS04b, which express the highest levels of BPV-1 E5 among the analyzed cell lines. Actin protein levels were detected on whole cell lysates before immunoprecipitation to ensure equal protein loading and allow normalization. (b) Quantitative densitometric analysis of the bands was performed with Image Lab software (ChemiDoc, Bio-Rad Laboratories).