IndraLab

"\"TbetaRI phosphorylation of Smad2 on Ser465 and Ser467 is required for Smad2-Smad4 complex formation and signaling.\""

"Smad7 is known to participate in a negative feedback loop in which TGF- activation results in R-Smad translocation to the nucleus where Smad7 transcription is induced by R-Smad Smad4 complexes and the produced Smad7 protein subsequently inhibits TGF-beta signaling (19, 20)."

"Phosphorylation of the C-terminal serine residues in R-Smads by type I receptor kinases is a crucial step in TGF-b family signalling (Abdollah et al., 1997; Macias-Silva et al., 1996; Souchelnytskyi et al., 1997). The two most C-terminal serine residues become phosphorylated and, together with a third, non-phosphorylated serine residue, form an evolutionarily conserved SSXS motif in all R-Smads.... TGF-b and activin receptors phosphorylate Smad2 and Smad3, and BMP receptors phosphorylate Smad1, Smad5 and Smad8 (Chen et al., 1998) (Fig. 1). The consequence of R-Smad phosphorylation is the formation of oligomeric complexes with the Co-Smad, Smad4."