Figure 5.

Smad induction and nuclear translocation in WERI-Rb-1 cells after BMP4 treatment. (A) Western blot with a specific P-Smad1/5/8 antibody demonstrating a significant up-regulation of activated, phoshorylated Smad1/5/8 already 30min after addition of recombinant BMP4. Total Smad1 levels served as an internal control and remained constant. (B-E) Immunocytochemical staining of cells cultured for 1h in the presence of 40ng/ml recombinant BMP4 revealed that BMP4 treatment results in a significant translocation of Smad 1 into the nucleus (C,E), whereas the Smad staining is mainly cytoplasmic in the control (ctr.) group, only treated with 0.1% BSA in 4mM HCl, the solvent for recombinant human BMP4 (B,D). Arrowheads point to cytoplasmic Smad staining. Arrows demarcate Smad translocation to the nucleus. Scale bar in (B) = 50 µm also applies for C-E