Fig. 5. Effects of L- and S-endoglin on TGFβ1-ALK1 and TGFβ1-ALK5 signaling pathways. Cells were serum starved for 24 hours before TGFβ1 treatment. Total protein extracts from control (C) or TGFβ1-treated (T) myoblasts analyzed by western blot with anti-Id1 (A) and anti-PAI1 (C). Measures of densitometry of each band were performed and relative values are represented. Id1 and PAI1 histogram represents the mean of three different extracts. (B,D) Western blots of endoglin in L₆E₉ mock, L-endoglin (L-Endo) and S-endoglin (S-Endo). L₆E₉ cells were transiently transfected with (Bre)₂-Luc reporter (^*P<0.05 compared with mock and S-Endo) (B), and (CAGA)₁₂-Luc reporter (^*P<0.05 TGFβ1 compared with control; ^**P<0.05 compared with mock and S-Endo; ^***P< 0.05 compared with mock and L-Endo). (D) Cells were incubated or not with TGFβ1 for 24 hours before measuring the luciferase activity.