Figure 2.

Palbociclib decreases Ser255 phosphorylation of SMAD2. A, Site‐specific phosphorylation of SMAD2 after palbociclib treatment. T47D cells were treated with 1 μmol/L palbociclib for 24 h. B, Schematic representation of representative phosphorylation sites of human SMAD2 protein. C, Validation of anti‐phospho‐SMAD2 Ser255. HEK293T cells were transfected with indicated plasmids. D, T47D cells were treated with indicated concentrations of palbociclib for 24 h to evaluate substrate phosphorylation. E, Immunoblot analysis of subcellular fractions prepared from T47D cells treated with ActA for 1.5 h and 1 μmol/L palbociclib for 24 h