Figure 5. Simplified TGF-β pathway. Several genes in this pathway are included in our analysis (TGFβ 1/2, BAMBI, ATF3, ID1), as well as associated genes that were not analyzed (TGF-β RI/II, SMAD3). TGF-β1 or 2 binds to the TGF-β RI and RII receptor complex, and results in signal transduction. However, if the TGFβ ligand binds to a BAMBI/TGF-β RI complex, this signal is not transduced. TGF-β signaling can lead to the binding of SMAD3 with ATF3. This complex can go on to repress the transcription of ID1. Independently of the TGF-β pathway, DDIT3 protein can inhibit the transcription of ATF3, while ATF3 can also suppress the transcription of DDIT3 (insert).