text_1: Knockout proximal tubule-specific deletion of the BMP receptor Alk3 causes fibrosis.
text_2: We also found that its deletion in the tubular epithelium leads to enhanced TGF-β1-Smad family member 3 (Smad3) signaling, epithelial damage and fibrosis, suggesting a protective role for Alk3-mediated signaling in the kidney.