Fig. 2From: Mathematical model of TGF-βsignalling: feedback coupling is consistent with signal switchingThe semi-reduced TGF-β signal transduction reactions. The red dashed lines which originate from phosphorylated SMAD trimer indirectly regulate the receptor levels. All the reactions from trimerization of phospho-SMAD2/3 to SMAD7 transcription and translation are reduced to the red dashed lines (see Fig. 1 for clarification). The dotted ends of red dashed lines show that included reactions could lead to both inhibition and stimulation of their targeting reactions (demonstrating negative and positive feedback effects). In this figure S is specifically used for SMAD2/3Back to article page