The level of phosphorylated Smad2 (P-Smad2) and total Smad2 (Smad2) was assessed by immunoblotting and β-actin was used as a loading control. Lower bar graphs show WB quantification of P-Smad2 (P-S2) normalized to β-actin. (B) 1603MED cells were treated with PBS (vehicle) or a blocking antibody targeting ActivinB (Ab α-ActB) or Follistatin. The p-values were determined by unpaired t-test. *p < 0.05, **p < 0.01, ***p < 0.001. Bars represent the mean ± SD. Number of replicates is n≥3. 