Colorectal carcinogenesis: Insights into the cell death and signal transduction pathways: A review

Figure 5 TGF/Smad pathway. TGFβ signalling is initiated via the binding of the TGFβ1 ligand to receptor II, which promotes dimerization between receptor II and receptor I and the subsequent transphosphorylation of TGFβRI. Activated TGFβRI therein phosphorylates and activates receptor-regulated Smads (Smad2 and Smad3). Phosphorylated Smads, along with co-Smads, form a trimeric complex and translocate to the nucleus to induce the transcription of target genes and promote cell growth and survival. TGF: Transforming growth factor.