SARA TGFB1:TGFBR2:p-TGFBR1 SMAD2/3 TGFB1:p-TGFBR:SARA:SMAD2/3 An anchoring protein, SARA, recruits SMAD2/3 Authored: Heldin, CH, Moustakas, A, Huminiecki, L, Jassal, B, 2006-02-02 Edited: Jassal, B, 2006-01-18 10:19:52 Pubmed9865696 Reactome Database ID Release 43170835 Reactome, http://www.reactome.org ReactomeREACT_6923 Reviewed: Heldin, CH, 2006-04-18 14:26:12 Reviewed: Huang, Tao, 2012-05-14 The activated TGF-beta receptor complex is internalized by clathrin-mediated endocytosis into early endosomes. SARA resides in the membrane of early endosomes. Crystallographic studies suggest that dimeric SARA in the early endosome coordinates two R-SMAD molecules (SMAD2 and/or SMAD3) per one receptor complex.