Structural highlights
Function
SMUF2_HUMAN E3 ubiquitin-protein ligase which accepts ubiquitin from an E2 ubiquitin-conjugating enzyme in the form of a thioester and then directly transfers the ubiquitin to targeted substrates. Interacts with SMAD1 and SMAD7 in order to trigger their ubiquitination and proteasome-dependent degradation. In addition, interaction with SMAD7 activates autocatalytic degradation, which is prevented by interaction with SCYE1. Forms a stable complex with the TGF-beta receptor-mediated phosphorylated SMAD2 and SMAD3. In this way, SMAD2 may recruit substrates, such as SNON, for ubiquitin-mediated degradation. Enhances the inhibitory activity of SMAD7 and reduces the transcriptional activity of SMAD2. Coexpression of SMURF2 with SMAD1 results in considerable decrease in steady-state level of SMAD1 protein and a smaller decrease of SMAD2 level.[1] [2]
Publication Abstract from PubMed
Transforming growth factor (TGF)-beta and BMP signaling is mediated by Smads 1-5 (R-Smads and Co-Smads) and inhibited by Smad7, a major hub of regulation of TGF-beta and BMP receptors by negative feedback and antagonistic signals. The transcription coactivator YAP and the E3 ubiquitin ligases Smurf1/2 and Nedd4L target R-Smads for activation or degradation, respectively. Pairs of WW domain in these regulators bind PY motifs and adjacent CDK/MAPK and GSK3 phosphorylation sites in R-Smads in a selective and regulated manner. In contrast, here we show that Smad7 binds YAP, Smurf1, Smurf2, and Nedd4L constitutively, the binding involving a PY motif in Smad7 and no phosphorylation. We also provide a structural basis for how regulators that use WW domain pairs for selective interactions with R-Smads, resort to one single versatile WW domain for binding Smad7 to centralize regulation in the TGF-beta and BMP pathways.
Structural Basis for the Versatile Interactions of Smad7 with Regulator WW Domains in TGF-beta Pathways.,Aragon E, Goerner N, Xi Q, Gomes T, Gao S, Massague J, Macias MJ Structure. 2012 Oct 10;20(10):1726-36. doi: 10.1016/j.str.2012.07.014. Epub 2012 , Aug 23. PMID:22921829[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Bonni S, Wang HR, Causing CG, Kavsak P, Stroschein SL, Luo K, Wrana JL. TGF-beta induces assembly of a Smad2-Smurf2 ubiquitin ligase complex that targets SnoN for degradation. Nat Cell Biol. 2001 Jun;3(6):587-95. PMID:11389444 doi:10.1038/35078562
- ↑ Di Guglielmo GM, Le Roy C, Goodfellow AF, Wrana JL. Distinct endocytic pathways regulate TGF-beta receptor signalling and turnover. Nat Cell Biol. 2003 May;5(5):410-21. PMID:12717440 doi:10.1038/ncb975
- ↑ Aragon E, Goerner N, Xi Q, Gomes T, Gao S, Massague J, Macias MJ. Structural Basis for the Versatile Interactions of Smad7 with Regulator WW Domains in TGF-beta Pathways. Structure. 2012 Oct 10;20(10):1726-36. doi: 10.1016/j.str.2012.07.014. Epub 2012 , Aug 23. PMID:22921829 doi:http://dx.doi.org/10.1016/j.str.2012.07.014
