Specificity of the inhibitory effects of Dad on TGF-β family type I receptors, Thickveins, Saxophone, and Baboon in Drosophila

In mammals, two inhibitory Smads (I-Smads), Smad6 and Smad7, play pivotal roles in negative regulation of TGF-β family signaling. Smad7 ubiquitously inhibits TGF-β family signaling, whereas Smad6 inhibits signaling from the ALK-3/6 subfamily in preference to that from the ALK-1/2 and ALK-4/5/7 subfamilies of TGF-β family type I receptors. In Drosophila, only one I-Smad, Dad, has been identified. Here we examined inhibitory effects of Dad on type I receptors in Drosophila. Dad inhibited Saxophone (ALK-1/2 orthologue) and Thickveins (ALK-3/6 orthologue) but not Baboon (ALK-4/5/7 orthologue). The differential modes of action of I-Smads in mammals and Drosophila are discussed.Structured summaryMINT-6596817:Smad7 (uniprotkb:O35253) physically interacts (MI:0218) with Sax (uniprotkb:Q7JQ39) by anti tag coimmunoprecipitation (MI:0007)MINT-6596699:Dad (uniprotkb:O15968) physically interacts (MI:0218) with Sax (uniprotkb:Q7JQ39) by anti tag coimmunoprecipitation (MI:0007)MINT-6596805:Smad7 (uniprotkb:O35253) physically interacts (MI:0218) with Thv (uniprotkb:Q95SI0) by anti tag coimmunoprecipitation (MI:0007)MINT-6596829:Smad7 (uniprotkb:O35253) physically interacts (MI:0218) with Babo (uniprotkb:A1Z7L9) by anti tag coimmunoprecipitation (MI:0007)MINT-6596719:Dad (uniprotkb:O15968) physically interacts (MI:0218) with Thv (uniprotkb:Q95SI0) by anti tag coimmunoprecipitation (MI:0007)