SARA是Smad锚着蛋白，可与Smad2/3直接结合，募集Smad2/3至TGF-β受体，是TGF-β信号通路中重要的衔接蛋白。SARA通过改变Smad2和Smad3的活化水平调节TGF-β信号转导，在Smad2的活化中起至关重要的作用。SARA也能与蛋白磷酸酶1的催化亚单位(PP1c)相结合，参与Smad7介导的TGF-β I型受体(TβR-I)去磷酸化。SARA的表达水平与上皮细胞转分化及纤维化的程度密切相关，参与上皮细胞转分化的调控。靶向SARA的干预策略是治疗TGF-β介导的上皮细胞转分化及纤维化的新路径。

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.

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