Fig. 3.

The bone morphogenetic protein (BMP) pathway is reduced during culture of mouse ATII cells. ATII cells were freshly isolated (D0) or cultured for 7 days on tissue culture plastic. The mRNA expression levels of Bmp-4 and Bmp-2 (A) or Bmpr1a (alk3) and Bmpr1b (alk6) (B) were determined by qRT-PCR and graphed relative to values obtained on D0; n = 3; *P < 0.05 compared with D0. C: cell lysates were harvested at the stated times and immunoblotted for phospho-SMAD1/5/8, SMAD1, and SMAD5, with β-actin used as a loading control. Blots are representative of 3 experiments with similar results.