Figure 1.

Transforming growth factor β (TGF-β) and bone morphogenetic proteins (BMP) signaling pathway. The canonical signaling pathway for TGF-β and BMP occurs through R-SMAD proteins, SMAD2/3 for TGF-β and SMAD1/5/8 for BMP. In both cases, Co-SMAD4 forms a complex with R-SMADs, and the timeric complex is translocated into the nucleus where it functions as a transcription factor. I-SMAD6/7 act as negative regulators of TGF-β and BMP signaling. The non-canonical signaling pathway works through non-SMAD proteins like ERK-MAP kinase, p38/JNK, RhoA/ROCK, JAK/STAT, or PI3K/AKT/mTOR. Created with BioRender.com.