| Structural highlights
Function
SMAD2_HUMAN Receptor-regulated SMAD (R-SMAD) that is an intracellular signal transducer and transcriptional modulator activated by TGF-beta (transforming growth factor) and activin type 1 receptor kinases. Binds the TRE element in the promoter region of many genes that are regulated by TGF-beta and, on formation of the SMAD2/SMAD4 complex, activates transcription. May act as a tumor suppressor in colorectal carcinoma. Positively regulates PDPK1 kinase activity by stimulating its dissociation from the 14-3-3 protein YWHAQ which acts as a negative regulator.[1] [2] [3] [4] [5]
Publication Abstract from PubMed
Shprintzen-Goldberg syndrome (SGS) is a multisystemic connective tissue disorder, with considerable clinical overlap with Marfan and Loeys-Dietz syndromes. These syndromes have commonly been associated with enhanced TGF-beta signaling. In SGS patients, heterozygous point mutations have been mapped to the transcriptional co-repressor SKI, which is a negative regulator of TGF-beta signaling that is rapidly degraded upon ligand stimulation. The molecular consequences of these mutations, however, are not understood. Here we use a combination of structural biology, genome editing, and biochemistry to show that SGS mutations in SKI abolish its binding to phosphorylated SMAD2 and SMAD3. This results in stabilization of SKI and consequently attenuation of TGF-beta responses, both in knockin cells expressing an SGS mutation and in fibroblasts from SGS patients. Thus, we reveal that SGS is associated with an attenuation of TGF-beta-induced transcriptional responses, and not enhancement, which has important implications for other Marfan-related syndromes.
Mutations in SKI in Shprintzen-Goldberg syndrome lead to attenuated TGF-beta responses through SKI stabilization.,Gori I, George R, Purkiss AG, Strohbuecker S, Randall RA, Ogrodowicz R, Carmignac V, Faivre L, Joshi D, Kjaer S, Hill CS Elife. 2021 Jan 8;10:e63545. doi: 10.7554/eLife.63545. PMID:33416497[6]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Lebrun JJ, Takabe K, Chen Y, Vale W. Roles of pathway-specific and inhibitory Smads in activin receptor signaling. Mol Endocrinol. 1999 Jan;13(1):15-23. PMID:9892009
- ↑ Lin X, Duan X, Liang YY, Su Y, Wrighton KH, Long J, Hu M, Davis CM, Wang J, Brunicardi FC, Shi Y, Chen YG, Meng A, Feng XH. PPM1A functions as a Smad phosphatase to terminate TGFbeta signaling. Cell. 2006 Jun 2;125(5):915-28. PMID:16751101 doi:10.1016/j.cell.2006.03.044
- ↑ Seong HA, Jung H, Kim KT, Ha H. 3-Phosphoinositide-dependent PDK1 negatively regulates transforming growth factor-beta-induced signaling in a kinase-dependent manner through physical interaction with Smad proteins. J Biol Chem. 2007 Apr 20;282(16):12272-89. Epub 2007 Feb 27. PMID:17327236 doi:10.1074/jbc.M609279200
- ↑ Inoue Y, Itoh Y, Abe K, Okamoto T, Daitoku H, Fukamizu A, Onozaki K, Hayashi H. Smad3 is acetylated by p300/CBP to regulate its transactivation activity. Oncogene. 2007 Jan 25;26(4):500-8. Epub 2006 Jul 24. PMID:16862174 doi:10.1038/sj.onc.1209826
- ↑ Dai F, Lin X, Chang C, Feng XH. Nuclear export of Smad2 and Smad3 by RanBP3 facilitates termination of TGF-beta signaling. Dev Cell. 2009 Mar;16(3):345-57. doi: 10.1016/j.devcel.2009.01.022. PMID:19289081 doi:10.1016/j.devcel.2009.01.022
- ↑ Gori I, George R, Purkiss AG, Strohbuecker S, Randall RA, Ogrodowicz R, Carmignac V, Faivre L, Joshi D, Kjær S, Hill CS. Mutations in SKI in Shprintzen-Goldberg syndrome lead to attenuated TGF-β responses through SKI stabilization. Elife. 2021 Jan 8;10:e63545. PMID:33416497 doi:10.7554/eLife.63545
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