Fig. 4.

Simplified schematic of the TGF/BMP signalling pathway. TGF-β and BMP family ligands typically signal through different receptors. This results in differences in SMAD activation with TGF-β typically activating SMAD2/3 signalling and BMP typically activating SMAD1/5/8 signalling. Activation and SMAD-mediated gene transcription. However, at high concentrations, TGF-β can also induce SMAD1/5/8 signalling. In chondrocytes, this leads to stimulation rather than inhibition of chondrocyte hypertrophy. The figure was created using Biorender.com