Abstract

The classical transforming growth factor-β (TGF-β)/bone morphogenetic protein (BMP) signaling pathway is one of the most crucial pathways in organisms, has been studied in mammals for decades. However, the mothers against decapentaplegic homolog (Smad) transducers members of TGF-β/BMP signaling are significantly expand in teleosts, making its intracellular signal transduction mechanisms highly complex. In this study, we focused on the zebrafish smad4a/b/c/d paralogous and systematically investigated their fate after gene duplications. The results demonstrate that zebrafish smad4a/b/c/d paralogous have undergone pronounced sub-functionalization, and exhibited substantial functional differences in expression pattern, subcellular localization, protein-protein interactions, and target site motifs. Our findings partially revealed the functional roles of smad4a/b/c/d paralogous in intracellular TGF-β/BMP signal transduction, offering essential theoretical support for future molecular biological research in zebrafish.