Fig. 8. Interaction between Notch 1 ICD and SMAD1. (A) Western blot of a pull-down with a GST-Notch 1 ICD fusion protein from lysates of cells transfected with CSL or SMAD1 proteins. The precipitated SMAD1 protein was visualized using a Flag antibody (the two lanes to the left), and the CSL protein using a Myc antibody (the two lanes to the right). Note that a small amount of SMAD1 was precipitated by GST-Notch 1 ICD, but not by GST. (B) Immunoprecipitation from COS-7 cells transfected with Flag-tagged SMAD1 or Flag-tagged P/CAF in the presence of Myc-tagged Notch 1 ICD. Immunoprecipitation with an anti-Flag-antibody was followed by analysis by western blot using an anti-Myc antibody.