FIG. 7.
Phospho-Smad2 is dephosphorylated at a similar rate throughout signaling. (A) PE25 cells were exposed to either 25 or 200 pM TGF-β for either 30 min or 6 h and then exposed to 10 μM TβRI inhibitor SB-431542. Phospho-Smad2 (P-Smad2) and Smad2 in whole-cell lysates was measured by immunoblotting every 15 min for 2 h after applying the TβRI inhibitor. (B) Phospho-Smad2 decreased to basal levels by about 60 min in each case, whereas Smad2 levels did not change appreciably. Cntl, untreated control.