FIGURE 1.

TGFβ stimulates Smad1 phosphorylation in a variety of cell lines. A, TGFβ induces Smad1 phosphorylation in C2C12 cells. C2C12 cells were cultured in the presence or absence of TGFβ or BMP for 1 h, and harvested for Western blot analysis with anti-Smad and anti-phospho-Smad antibodies as detailed under “Experimental Procedures.” B, TGFβ induces Smad1 phosphorylation in HepG2 cells. HepG2 cells were cultured in the presence or absence of TGFβ or BMP for 1 h, and harvested for Western blot analysis as in A. C, TGFβ induces Smad1 phosphorylation in MEF cells. MEF cells were cultured in the presence or absence of TGFβ or BMP for 1 h, and harvested for Western blot analysis as in A. IB, immunoblot.