TGFβ-induced Smad1 phosphorylation is independent of BMP type I
receptors in certain cell lines. A, C2C12 cells were co-treated
with ligand (TGFβ or BMP) and ALK inhibitor
(SB431542 or DM), as indicated, for 1.5 h prior to harvest
for Western blot analysis as described in the legend to
Fig. 1A. B,
HepG2 cells were co-treated with ligand (TGFβ or BMP)
and ALK inhibitor (SB431542 or DM), as indicated, for 1.5 h
prior to harvest for Western blot analysis as described in the legend to
Fig. 1A. C,
MEF cells were co-treated with ligand (TGFβ or BMP) and ALK inhibitor
(SB431542 or DM), as indicated, for 1.5 h prior to harvest for Western blot
analysis as described in the legend to Fig.
1A. D, HaCaT cells were co-treated with ligand
(TGFβ or BMP) and ALK inhibitor (SB431542 or
DM), as indicated, for 1.5 h prior to harvest for Western blot
analysis as described in the legend to Fig.
1A. IB, immunoblot.