TGFβ stimulates of ALK5-mediated phosphorylation of ΔNp63α via TGFBR2. A.

<p>IMEC cells were treated with the indicated concentrations of TGFβ1 ligand for 1 hr. Whole cell lysates were harvested and analyzed by immunoblotting for levels of phospho-p63, total p63, phospho-SMAD2 and β-actin. <b>B.</b> ALK5-mediated phosphorylation of ΔNp63α is inhibited by A83-01<b>.</b> IMEC cells were treated with A83-01 at the indicated concentrations 1 hr prior to TGFβ1 treatment. Whole cell extracts were analyzed after 1 hr for phospho-p63, total-p63, phospho-SMAD2 and β-actin via immunoblotting. <b>C.</b> SiRNA targeted against TGFβR2 was transfected into IMEC cells, 48 hrs later cells were transfected with ΔNp63α expression vector or GPP control vector. Whole cell lysates were harvested 24 hrs later and analyzed for phospho-P63, total-P63, phospho-SMAD2 and β-actin. <b>D.</b> Ectopic expression of ALK5 and TGFβR2 is sufficient to phosphorylate ΔNp63α in a manner that is independent of TGFB.