Structure and function of the Smad anchor protein

Smad anchor for receptor activation(SARA) is known as Smad cofactor that interacts directly with Smad2/3 and functions to recruit Smad2/3 to the TGF-β receptor.SARA plays an essential role in TGF-β-induced Smad2 activation and can modulate TGF-β signaling through regulating the activity of Smad2 and Smad3.SARA also functions as an anchor for catalytic subunit of protein phosphatase 1(PP1c) and may be involved in the Smad7-mediated dephosphorylation of TGF-β Type I receptor(TβR-I).The SARA expression level closely relates to the development of epithelial cell transdifferentiation and fibrosis.It participates in the modulation of epithelial cell transdifferentiation.Targeted interference of SARA may provide a new therapeutical approach to TGF-β-mediated epithelial cell transdifferentiation and fibrosis.