SMAD-like domain superfamily
IPR017855
Definition
This superfamily represents SMAD (Mothers against decapentaplegic (MAD) homolog) (also called MH2 for MAD homology 2) domains as well as their structural homologues, such as the transactivation domain of interferon regulatory protein 3 (IRF3), both of which have a β-sandwich structural fold. SMAD domains are found at the C terminus of MAD related proteins such as Smads. SMAD domain proteins are found in a range of species from nematodes to humans. These highly conserved proteins contain an N-terminal MH1 domain that contacts DNA, and is separated by a short linker region from the C-terminal MH2 domain, the later showing a striking similarity to FHA domains. SMAD proteins mediate signalling by the TGF-beta/activin/BMP-2/4 cytokines from receptor Ser/Thr protein kinases at the cell surface to the nucleus. SMAD proteins fall into three functional classes: the receptor-regulated SMADs (R-SMADs), including SMAD1, -2, -3, -5, and -8, each of which is involved in a ligand-specific signalling pathway PMID:11779503; the co-mediator SMADs (co-SMADs), including SMAD4, which interact with R-SMADs to participate in signalling PMID:9214508; and the inhibitory SMADs (I-SMADs), including SMAD6 and -7, which block the activation of R-SMADs and Co-SMADs, thereby negatively regulating signalling pathways PMID:11483516.
15 human proteins with this domain
Each is a reviewed human protein in the Seroatlas serome and a potential autoantibody target; this domain groups them into one antibody-relevant category. Every entry links to its own record.
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