Ski-interacting Protein Interacts with Smad Proteins to Augment Transforming Growth Factor-β-dependent Transcription

Abstract

Transforming growth factor-β (TGF-β) signaling requires the action of Smad proteins in association with other DNA-binding factors and coactivator and corepressor proteins to modulate target gene transcription. Smad2 and Smad3 both associate with the c-Ski and Sno oncoproteins to repress transcription of Smad target genes via recruitment of a nuclear corepressor complex. Ski-interacting protein (SKIP), a nuclear hormone receptor coactivator, was examined as a possible modulator of transcriptional regulation of the TGF-β-responsive promoter from the plasminogen activator inhibitor gene-1. SKIP augmented TGF-β-dependent transactivation in contrast to Ski/Sno-dependent repression of this reporter. SKIP interacted with Smad2 and Smad3 proteins in vivo in yeast and in mammalian cells through a region of SKIP between amino acids 201–333. In vitro, deletion of the Mad homology domain 2 (MH2) domain of Smad3 abrogated SKIP binding, like Ski/Sno, but the MH2 domain of Smad3 alone was not sufficient for protein-protein interaction. Overexpression of SKIP partially overcame Ski/Sno-dependent repression, whereas Ski/Sno overexpression attenuated SKIP augmentation of TGF-β-dependent transcription. Our results suggest a potential mechanism for transcriptional control of TGF-β signaling that involves the opposing and competitive actions of SKIP and Smad MH2-interacting factors, such as Ski and/or Sno. Thus, SKIP appears to modulate both TGF-β and nuclear hormone receptor signaling pathways. Transforming growth factor-β (TGF-β) signaling requires the action of Smad proteins in association with other DNA-binding factors and coactivator and corepressor proteins to modulate target gene transcription. Smad2 and Smad3 both associate with the c-Ski and Sno oncoproteins to repress transcription of Smad target genes via recruitment of a nuclear corepressor complex. Ski-interacting protein (SKIP), a nuclear hormone receptor coactivator, was examined as a possible modulator of transcriptional regulation of the TGF-β-responsive promoter from the plasminogen activator inhibitor gene-1. SKIP augmented TGF-β-dependent transactivation in contrast to Ski/Sno-dependent repression of this reporter. SKIP interacted with Smad2 and Smad3 proteins in vivo in yeast and in mammalian cells through a region of SKIP between amino acids 201–333. In vitro, deletion of the Mad homology domain 2 (MH2) domain of Smad3 abrogated SKIP binding, like Ski/Sno, but the MH2 domain of Smad3 alone was not sufficient for protein-protein interaction. Overexpression of SKIP partially overcame Ski/Sno-dependent repression, whereas Ski/Sno overexpression attenuated SKIP augmentation of TGF-β-dependent transcription. Our results suggest a potential mechanism for transcriptional control of TGF-β signaling that involves the opposing and competitive actions of SKIP and Smad MH2-interacting factors, such as Ski and/or Sno. Thus, SKIP appears to modulate both TGF-β and nuclear hormone receptor signaling pathways. transforming growth factor-β Ski-interacting protein nuclear corepressor plasminogen activator inhibitor gene-1 Mad homology domain 1 Mad homology domain 2 bone-morphogenetic protein Smad-binding element vitamin D receptor silencing mediator for retinoic acid and thyroid receptors GAL4 activation domain GAL4 DNA-binding domain amino acid(s) hemagglutinin glutathioneS-transferase polymerase chain reaction polyacrylamide gel electrophoresis Transforming growth factor-β (TGF-β)1 superfamily members are multifunctional cell-cell signaling proteins, which include the TGF-βs, bone-morphogenetic proteins (BMPs), activins, and inhibins, mullerian-inhibiting substance and growth differentiation factors (1Massague J. Wotton D. EMBO J. 2000; 19: 1745-1754Crossref PubMed Google Scholar). Members of this superfamily mediate many key cellular events in growth and development and are evolutionarily conserved fromDrosophila to mammals (2Whitman M. Genes Dev. 1998; 12: 2445-2462Crossref PubMed Scopus (441) Google Scholar). TGF-β signaling requires the action of a family of DNA-binding proteins called Smads, including TGF-β-specific (Smad2 and Smad3), BMP-specific (Smad1, Smad5 and Smad8), a common Smad4, and anti-Smads (Smad6 and Smad7). TGF-β signals through sequential activation of two cell surface receptor serine-threonine kinases, which phosphorylate Smad2 and/or Smad3. Phosphorylated Smad2 or Smad3, together with Smad4, translocates into the nucleus where the Smad heterodimer binds Smad-binding elements (SBEs) in association with other nuclear factors in promoters of target genes (1Massague J. Wotton D. EMBO J. 2000; 19: 1745-1754Crossref PubMed Google Scholar, 3Nakao A. Imamura T. Souchelnytskyi S. Kawabata M. Ishisaki A. Oeda E. Tamaki K. Hanai J. Heldin C.H. Miyazono K. Tendijke P. EMBO J. 1997; 16: 5353-5362Crossref PubMed Scopus (901) Google Scholar, 4Wrana J.L. Cell. 2000; 100: 189-192Abstract Full Text Full Text PDF PubMed Scopus (363) Google Scholar).Recently it has been shown that Smad proteins also interact with other nuclear factors such as c-Ski and the Ski-related novel (Sno) protein and nuclear hormone receptors, including the vitamin D receptor (VDR) to modulate TGF-β signaling (5Sun Y. Liu X.D. Eaton E.N. Lane W.S. Lodish H.F. Weinberg R.A. Mol. Cell. 1999; 4: 499-509Abstract Full Text Full Text PDF PubMed Scopus (224) Google Scholar, 6Stroschein S.L. Wang W. Zhou S.L. Zhou Q. Luo K.X. Science. 1999; 286: 771-774Crossref PubMed Scopus (436) Google Scholar, 7Akiyoshi S. Inoue H. Hanai J. Kusanagi K. Nemoto N. Miyazono K. Kawabata M. J. Biol. Chem. 1999; 274: 35269-35277Abstract Full Text Full Text PDF PubMed Scopus (335) Google Scholar, 8Xu W.D. Angelis K. Danielpour D. Haddad M.M. Bischof O. Campisi J. Stavnezer E. Medrano E.E. Proc. Natl. Acad. Sci. U. S. A. 2000; 97: 5924-5929Crossref PubMed Scopus (180) Google Scholar, 9Yanagisawa J. Yanagi Y. Masuhiro Y. Suzawa M. Watanabe M. Kashiwagi K. Toriyabe T. Kawabata M. Miyazono K. Kato S. Science. 1999; 283: 1317-1321Crossref PubMed Scopus (417) Google Scholar, 10Subramaniam N. Leong G.M. Cock T.-A. Flanagan J.L. Fong C. Eisman J.A. Kouzmenko A.P. J. Biol. Chem. 2001; 276: 15741-15746Abstract Full Text Full Text PDF PubMed Scopus (76) Google Scholar). Ski and Sno are involved in oncogenic transformation and enhancement of muscle differentiation by blocking TGF-β signaling (11Colmenares C. Stavnezer E. Cell. 1989; 59: 293-303Abstract Full Text PDF PubMed Scopus (150) Google Scholar, 12Berk M. Desai S.Y. Heyman H.C. Colmenares C. Genes Dev. 1997; 11: 2029-2039Crossref PubMed Scopus (165) Google Scholar, 13Sutrave P. Kelly A.M. Hughes S.H. Genes Dev. 1990; 4: 1462-1472Crossref PubMed Scopus (140) Google Scholar, 14Colmenares C. Sutrave P. Hughes S.H. Stavnezer E. J. Virol. 1991; 65: 4929-4935Crossref PubMed Google Scholar). The mechanism of Ski/Sno repression of TGF-β signaling appears to involve an interaction with a complex consisting of the nuclear corepressor (N-CoR) and a histone deacetylase enzyme (15Luo K.X. Stroschein S.L. Wang W. Chen D. Martens E. Zhou S. Zhou Q. Genes Dev. 1999; 13: 2196-2206Crossref PubMed Scopus (389) Google Scholar, 16Nomura T. Khan M.M. Kaul S.C. Dong H.D. Wadhwa R. Colmenares C. Kohno I. Ishii S. Genes Dev. 1999; 13: 412-423Crossref PubMed Scopus (251) Google Scholar). N-CoR, and its related co-repressor silencing mediator for retinoic acid and thyroid receptors (SMRT), interact with a wide variety of other nuclear factors to mediate transcriptional repression (17Horlein A.J. Naar A.M. Heinzel T. Torchia J. Gloss B. Kurokawa R. Ryan A. Kamel Y. Soderstrom M. Glass C.K. Rosenfeld M.G. Nature. PubMed Scopus Google Scholar, Nature. PubMed Scopus Google Scholar, A. J. Scopus Google Scholar). the Ski-interacting protein was in a two as a and was as a and R. B. 1998; 16: PubMed Scopus Google Scholar, S.C. J. Biol. Chem. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, M. Chen J. Virol. 1999; Scopus Google Scholar). Thus, the that SKIP and signaling that SKIP a in the regulation of a of and cellular signaling M. Chen A. Mol. Cell. Biol. 2000; PubMed Scopus Google Ski and Sno modulate TGF-β-dependent it was of to SKIP also modulate the through interaction with the Smad In this in contrast to and repression, SKIP augmented TGF-β-dependent transcription. region of to for the Smad interaction. SKIP interacted in and in vivo with Smad3 and partially and repression, Ski/Sno attenuated SKIP transactivation of TGF-β results suggest that SKIP an to Ski and Sno in the control of TGF-β-dependent Ski and Sno oncoproteins been shown to modulate TGF-β signaling through an interaction with a complex (15Luo K.X. Stroschein S.L. Wang W. Chen D. Martens E. Zhou S. Zhou Q. Genes Dev. 1999; 13: 2196-2206Crossref PubMed Scopus (389) Google Scholar). a nuclear hormone also with both Ski and this was to the potential of SKIP in TGF-β In SKIP augmented transcription and a interaction with Smad interaction was both in as by and yeast two protein-protein The region between and SKIP to as the like Ski and interacted with the MH2 domain of Smad3. Ski and Sno attenuated SKIP SKIP partially and transcriptional MH2 domain of Smad2 and Smad3 has been to a key region involved in protein-protein including with the and the Smad Ski and Sno (1Massague J. Wotton D. EMBO J. 2000; 19: 1745-1754Crossref PubMed Google Scholar). The domain of the to a (1Massague J. Wotton D. EMBO J. 2000; 19: 1745-1754Crossref PubMed Google Scholar). TGF-β-responsive promoters of other DNA-binding factors, such as and as as factors through protein-protein interaction with the are involved in the and of Smad target gene action Lodish H.F. Proc. Natl. Acad. Sci. U. S. A. 1999; PubMed Scopus Google Scholar, M. Nature. PubMed Scopus Google Scholar, Y. R. Nature. 1998; PubMed Scopus Google Scholar). SKIP appears to a in augmentation of TGF-β-specific Smad transcriptional via an interaction with the MH2 domain of Smad3. Our also as SKIP was to interact with an MH2 domain of Smad3 in and yeast that other the Smad proteins the of the Smad protein also modulate SKIP was to interact with Smad2 and Smad3 in SKIP with Smad3 with or Smad4, to the in in mammalian the J. A. J. Mol. Cell. Biol. PubMed Google Scholar). Thus, as SKIP interacted with Smad2 in vivo and in vitro, it also possible that SKIP in mammalian cells to modulate TGF-β signaling through Smad2 in E. C. J.L. Mol. Cell. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar). in the that Smad3 augmented as with this promoter (5Sun Y. Liu X.D. Eaton E.N. Lane W.S. Lodish H.F. Weinberg R.A. Mol. Cell. 1999; 4: 499-509Abstract Full Text Full Text PDF PubMed Scopus (224) Google but this was by to the for this of of SKIP in yeast and mammalian cells that the region of SKIP for Smad between yeast and mammalian the SKIP not interact with Smad2 or Smad3 in its transactivation in mammalian cells was to transactivation domain of SKIP that in mammalian from the Smad interaction with the domain to of SKIP involved in vitamin transactivation S.C. J. Biol. Chem. 1998; Full Text Full Text PDF PubMed Scopus Google SKIP with Ski/Sno and Smad3 in Ski/Sno interact with Smad3, to the that proteins a a gel the from the as in the The that both SKIP and Ski/Sno alone a complex with not the of a complex in the of Thus, are with the which between SKIP and Ski/Sno for Smad3 but the of a complex between this SKIP as a coactivator of TGF-β-dependent transcription. SKIP as a coactivator of nuclear hormone but also as a of signaling through its interaction with and histone deacetylase enzyme proteins S.C. J. Biol. Chem. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, M. Chen A. Mol. Cell. Biol. 2000; PubMed Scopus Google Scholar). of SKIP interaction of SKIP with nuclear SKIP from a transcriptional to activator through its interaction between the corepressor and M. Chen A. Mol. Cell. Biol. 2000; PubMed Scopus Google Scholar). In SKIP and Ski/Sno opposing transcriptional the that the cellular of Ski or Sno a TGF-β-dependent transcription and its cell growth and the domain of SKIP appears to also involved in interaction with Ski and Sno. and M. J. results and that like Ski/Sno, interacted with the MH2 domain of Smad3 suggest that the opposing transcriptional of SKIP and Ski/Sno involve for Smad3 between SKIP and and/or other Smad3 MH2-interacting factors, such as with S. Inoue H. Hanai J. Kusanagi K. Nemoto N. Miyazono K. Kawabata M. J. Biol. Chem. 1999; 274: 35269-35277Abstract Full Text Full Text PDF PubMed Scopus (335) Google Scholar, Y. R. Genes Dev. 1998; 12: PubMed Scopus Google Scholar, R. T. Genes Dev. 1998; 12: PubMed Scopus Google Scholar). Thus, the of SKIP through the MH2 domain the and of transcriptional as SKIP and Ski/Sno interact with other and also with the related an mechanism involve (1Massague J. Wotton D. EMBO J. 2000; 19: 1745-1754Crossref PubMed Google Scholar, K.X. Stroschein S.L. Wang W. Chen D. Martens E. Zhou S. Zhou Q. Genes Dev. 1999; 13: 2196-2206Crossref PubMed Scopus (389) Google Scholar, R. B. 1998; 16: PubMed Scopus Google Scholar, M. Chen A. Mol. Cell. Biol. 2000; PubMed Scopus Google Scholar). via SKIP of such as or from the Ski/Sno a mechanism to that for and Chen D. J. Biol. Chem. 1999; 274: Full Text Full Text PDF PubMed Scopus Google Scholar). the mechanism of SKIP it that SKIP a in of this cellular and signaling results a in which SKIP and with other MH2-interacting factors, such as c-Ski and to the transcriptional of a TGF-β-responsive target a potential for SKIP in the regulation of TGF-β cell growth and Transforming growth factor-β (TGF-β)1 superfamily members are multifunctional cell-cell signaling proteins, which include the TGF-βs, bone-morphogenetic proteins (BMPs), activins, and inhibins, mullerian-inhibiting substance and growth differentiation factors (1Massague J. Wotton D. EMBO J. 2000; 19: 1745-1754Crossref PubMed Google Scholar). Members of this superfamily mediate many key cellular events in growth and development and are evolutionarily conserved fromDrosophila to mammals (2Whitman M. Genes Dev. 1998; 12: 2445-2462Crossref PubMed Scopus (441) Google Scholar). TGF-β signaling requires the action of a family of DNA-binding proteins called Smads, including TGF-β-specific (Smad2 and Smad3), BMP-specific (Smad1, Smad5 and Smad8), a common Smad4, and anti-Smads (Smad6 and Smad7). TGF-β signals through sequential activation of two cell surface receptor serine-threonine kinases, which phosphorylate Smad2 and/or Smad3. Phosphorylated Smad2 or Smad3, together with Smad4, translocates into the nucleus where the Smad heterodimer binds Smad-binding elements (SBEs) in association with other nuclear factors in promoters of target genes (1Massague J. Wotton D. EMBO J. 2000; 19: 1745-1754Crossref PubMed Google Scholar, 3Nakao A. Imamura T. Souchelnytskyi S. Kawabata M. Ishisaki A. Oeda E. Tamaki K. Hanai J. Heldin C.H. Miyazono K. Tendijke P. EMBO J. 1997; 16: 5353-5362Crossref PubMed Scopus (901) Google Scholar, 4Wrana J.L. Cell. 2000; 100: 189-192Abstract Full Text Full Text PDF PubMed Scopus (363) Google Scholar). it has been shown that Smad proteins also interact with other nuclear factors such as c-Ski and the Ski-related novel (Sno) protein and nuclear hormone receptors, including the vitamin D receptor (VDR) to modulate TGF-β signaling (5Sun Y. Liu X.D. Eaton E.N. Lane W.S. Lodish H.F. Weinberg R.A. Mol. Cell. 1999; 4: 499-509Abstract Full Text Full Text PDF PubMed Scopus (224) Google Scholar, 6Stroschein S.L. Wang W. Zhou S.L. Zhou Q. Luo K.X. Science. 1999; 286: 771-774Crossref PubMed Scopus (436) Google Scholar, 7Akiyoshi S. Inoue H. Hanai J. Kusanagi K. Nemoto N. Miyazono K. Kawabata M. J. Biol. Chem. 1999; 274: 35269-35277Abstract Full Text Full Text PDF PubMed Scopus (335) Google Scholar, 8Xu W.D. Angelis K. Danielpour D. Haddad M.M. Bischof O. Campisi J. Stavnezer E. Medrano E.E. Proc. Natl. Acad. Sci. U. S. A. 2000; 97: 5924-5929Crossref PubMed Scopus (180) Google Scholar, 9Yanagisawa J. Yanagi Y. Masuhiro Y. Suzawa M. Watanabe M. Kashiwagi K. Toriyabe T. Kawabata M. Miyazono K. Kato S. Science. 1999; 283: 1317-1321Crossref PubMed Scopus (417) Google Scholar, 10Subramaniam N. Leong G.M. Cock T.-A. Flanagan J.L. Fong C. Eisman J.A. Kouzmenko A.P. J. Biol. Chem. 2001; 276: 15741-15746Abstract Full Text Full Text PDF PubMed Scopus (76) Google Scholar). Ski and Sno are involved in oncogenic transformation and enhancement of muscle differentiation by blocking TGF-β signaling (11Colmenares C. Stavnezer E. Cell. 1989; 59: 293-303Abstract Full Text PDF PubMed Scopus (150) Google Scholar, 12Berk M. Desai S.Y. Heyman H.C. Colmenares C. Genes Dev. 1997; 11: 2029-2039Crossref PubMed Scopus (165) Google Scholar, 13Sutrave P. Kelly A.M. Hughes S.H. Genes Dev. 1990; 4: 1462-1472Crossref PubMed Scopus (140) Google Scholar, 14Colmenares C. Sutrave P. Hughes S.H. Stavnezer E. J. Virol. 1991; 65: 4929-4935Crossref PubMed Google Scholar). The mechanism of Ski/Sno repression of TGF-β signaling appears to involve an interaction with a complex consisting of the nuclear corepressor (N-CoR) and a histone deacetylase enzyme (15Luo K.X. Stroschein S.L. Wang W. Chen D. Martens E. Zhou S. Zhou Q. Genes Dev. 1999; 13: 2196-2206Crossref PubMed Scopus (389) Google Scholar, 16Nomura T. Khan M.M. Kaul S.C. Dong H.D. Wadhwa R. Colmenares C. Kohno I. Ishii S. Genes Dev. 1999; 13: 412-423Crossref PubMed Scopus (251) Google Scholar). N-CoR, and its related co-repressor silencing mediator for retinoic acid and thyroid receptors (SMRT), interact with a wide variety of other nuclear factors to mediate transcriptional repression (17Horlein A.J. Naar A.M. Heinzel T. Torchia J. Gloss B. Kurokawa R. Ryan A. Kamel Y. Soderstrom M. Glass C.K. Rosenfeld M.G. Nature. PubMed Scopus Google Scholar, Nature. PubMed Scopus Google Scholar, A. J. Scopus Google Scholar). the Ski-interacting protein was in a two as a and was as a and R. B. 1998; 16: PubMed Scopus Google Scholar, S.C. J. Biol. Chem. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, M. Chen J. Virol. 1999; Scopus Google Scholar). Thus, the that SKIP and signaling that SKIP a in the regulation of a of and cellular signaling M. Chen A. Mol. Cell. Biol. 2000; PubMed Scopus Google Scholar). Ski and Sno modulate TGF-β-dependent it was of to SKIP also modulate the through interaction with the Smad In this in contrast to and repression, SKIP augmented TGF-β-dependent transcription. region of to for the Smad interaction. SKIP interacted in and in vivo with Smad3 and partially and repression, Ski/Sno attenuated SKIP transactivation of TGF-β results suggest that SKIP an to Ski and Sno in the control of TGF-β-dependent transcription. Ski and Sno oncoproteins been shown to modulate TGF-β signaling through an interaction with a complex (15Luo K.X. Stroschein S.L. Wang W. Chen D. Martens E. Zhou S. Zhou Q. Genes Dev. 1999; 13: 2196-2206Crossref PubMed Scopus (389) Google Scholar). a nuclear hormone also with both Ski and this was to the potential of SKIP in TGF-β In SKIP augmented transcription and a interaction with Smad interaction was both in as by and yeast two protein-protein The region between and SKIP to as the like Ski and interacted with the MH2 domain of Smad3. Ski and Sno attenuated SKIP SKIP partially and transcriptional MH2 domain of Smad2 and Smad3 has been to a key region involved in protein-protein including with the and the Smad Ski and Sno (1Massague J. Wotton D. EMBO J. 2000; 19: 1745-1754Crossref PubMed Google Scholar). The domain of the to a (1Massague J. Wotton D. EMBO J. 2000; 19: 1745-1754Crossref PubMed Google Scholar). TGF-β-responsive promoters of other DNA-binding factors, such as and as as factors through protein-protein interaction with the are involved in the and of Smad target gene action Lodish H.F. Proc. Natl. Acad. Sci. U. S. A. 1999; PubMed Scopus Google Scholar, M. Nature. PubMed Scopus Google Scholar, Y. R. Nature. 1998; PubMed Scopus Google Scholar). SKIP appears to a in augmentation of TGF-β-specific Smad transcriptional via an interaction with the MH2 domain of Smad3. Our also as SKIP was to interact with an MH2 domain of Smad3 in and yeast that other the Smad proteins the of the Smad protein also modulate SKIP was to interact with Smad2 and Smad3 in SKIP with Smad3 with or Smad4, to the in in mammalian the J. A. J. Mol. Cell. Biol. PubMed Google Scholar). Thus, as SKIP interacted with Smad2 in vivo and in vitro, it also possible that SKIP in mammalian cells to modulate TGF-β signaling through Smad2 in E. C. J.L. Mol. Cell. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar). in the that Smad3 augmented as with this promoter (5Sun Y. Liu X.D. Eaton E.N. Lane W.S. Lodish H.F. Weinberg R.A. Mol. Cell. 1999; 4: 499-509Abstract Full Text Full Text PDF PubMed Scopus (224) Google but this was by to the for this of of SKIP in yeast and mammalian cells that the region of SKIP for Smad between yeast and mammalian the SKIP not interact with Smad2 or Smad3 in its transactivation in mammalian cells was to transactivation domain of SKIP that in mammalian from the Smad interaction with the domain to of SKIP involved in vitamin transactivation S.C. J. Biol. Chem. 1998; Full Text Full Text PDF PubMed Scopus Google SKIP with Ski/Sno and Smad3 in Ski/Sno interact with Smad3, to the that proteins a a gel the from the as in the The that both SKIP and Ski/Sno alone a complex with not the of a complex in the of Thus, are with the which between SKIP and Ski/Sno for Smad3 but the of a complex between this SKIP as a coactivator of TGF-β-dependent transcription. SKIP as a coactivator of nuclear hormone but also as a of signaling through its interaction with and histone deacetylase enzyme proteins S.C. J. Biol. Chem. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, M. Chen A. Mol. Cell. Biol. 2000; PubMed Scopus Google Scholar). of SKIP interaction of SKIP with nuclear SKIP from a transcriptional to activator through its interaction between the corepressor and M. Chen A. Mol. Cell. Biol. 2000; PubMed Scopus Google Scholar). In SKIP and Ski/Sno opposing transcriptional the that the cellular of Ski or Sno a TGF-β-dependent transcription and its cell growth and the domain of SKIP appears to also involved in interaction with Ski and Sno. and M. J. results and that like Ski/Sno, interacted with the MH2 domain of Smad3 suggest that the opposing transcriptional of SKIP and Ski/Sno involve for Smad3 between SKIP and and/or other Smad3 MH2-interacting factors, such as with S. Inoue H. Hanai J. Kusanagi K. Nemoto N. Miyazono K. Kawabata M. J. Biol. Chem. 1999; 274: 35269-35277Abstract Full Text Full Text PDF PubMed Scopus (335) Google Scholar, Y. R. Genes Dev. 1998; 12: PubMed Scopus Google Scholar, R. T. Genes Dev. 1998; 12: PubMed Scopus Google Scholar). Thus, the of SKIP through the MH2 domain the and of transcriptional as SKIP and Ski/Sno interact with other and also with the related an mechanism involve (1Massague J. Wotton D. EMBO J. 2000; 19: 1745-1754Crossref PubMed Google Scholar, K.X. Stroschein S.L. Wang W. Chen D. Martens E. Zhou S. Zhou Q. Genes Dev. 1999; 13: 2196-2206Crossref PubMed Scopus (389) Google Scholar, R. B. 1998; 16: PubMed Scopus Google Scholar, M. Chen A. Mol. Cell. Biol. 2000; PubMed Scopus Google Scholar). via SKIP of such as or from the Ski/Sno a mechanism to that for and Chen D. J. Biol. Chem. 1999; 274: Full Text Full Text PDF PubMed Scopus Google Scholar). the mechanism of SKIP it that SKIP a in of this cellular and signaling results a in which SKIP and with other MH2-interacting factors, such as c-Ski and to the transcriptional of a TGF-β-responsive target a potential for SKIP in the regulation of TGF-β cell growth and The Ski and Sno oncoproteins been shown to modulate TGF-β signaling through an interaction with a complex (15Luo K.X. Stroschein S.L. Wang W. Chen D. Martens E. Zhou S. Zhou Q. Genes Dev. 1999; 13: 2196-2206Crossref PubMed Scopus (389) Google Scholar). a nuclear hormone also with both Ski and this was to the potential of SKIP in TGF-β In SKIP augmented transcription and a interaction with Smad interaction was both in as by and yeast two protein-protein The region between and SKIP to as the like Ski and interacted with the MH2 domain of Smad3. Ski and Sno attenuated SKIP SKIP partially and transcriptional The MH2 domain of Smad2 and Smad3 has been to a key region involved in protein-protein including with the and the Smad Ski and Sno (1Massague J. Wotton D. EMBO J. 2000; 19: 1745-1754Crossref PubMed Google Scholar). The domain of the to a (1Massague J. Wotton D. EMBO J. 2000; 19: 1745-1754Crossref PubMed Google Scholar). TGF-β-responsive promoters of other DNA-binding factors, such as and as as factors through protein-protein interaction with the are involved in the and of Smad target gene action Lodish H.F. Proc. Natl. Acad. Sci. U. S. A. 1999; PubMed Scopus Google Scholar, M. Nature. PubMed Scopus Google Scholar, Y. R. Nature. 1998; PubMed Scopus Google Scholar). SKIP appears to a in augmentation of TGF-β-specific Smad transcriptional via an interaction with the MH2 domain of Smad3. Our also as SKIP was to interact with an MH2 domain of Smad3 in and yeast that other the Smad proteins the of the Smad protein also modulate interaction. SKIP was to interact with Smad2 and Smad3 in SKIP with Smad3 with or Smad4, to the in in mammalian the J. A. J. Mol. Cell. Biol. PubMed Google Scholar). Thus, as SKIP interacted with Smad2 in vivo and in vitro, it also possible that SKIP in mammalian cells to modulate TGF-β signaling through Smad2 in E. C. J.L. Mol. Cell. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar). in the that Smad3 augmented as with this promoter (5Sun Y. Liu X.D. Eaton E.N. Lane W.S. Lodish H.F. Weinberg R.A. Mol. Cell. 1999; 4: 499-509Abstract Full Text Full Text PDF PubMed Scopus (224) Google but this was by to the for this of The of SKIP in yeast and mammalian cells that the region of SKIP for Smad between yeast and mammalian the SKIP not interact with Smad2 or Smad3 in its transactivation in mammalian cells was to transactivation domain of SKIP that in mammalian from the Smad interaction with the domain to of SKIP involved in vitamin transactivation S.C. J. Biol. Chem. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar). SKIP with Ski/Sno and Smad3 in Ski/Sno interact with Smad3, to the that proteins a a gel the from the as in the The that both SKIP and Ski/Sno alone a complex with not the of a complex in the of Thus, are with the which between SKIP and Ski/Sno for Smad3 but the of a complex between In this SKIP as a coactivator of TGF-β-dependent transcription. SKIP as a coactivator of nuclear hormone but also as a of signaling through its interaction with and histone deacetylase enzyme proteins S.C. J. Biol. Chem. 1998; Full Text Full Text PDF PubMed Scopus Google Scholar, M. Chen A. Mol. Cell. Biol. 2000; PubMed Scopus Google Scholar). of SKIP interaction of SKIP with nuclear SKIP from a transcriptional to activator through its interaction between the corepressor and M. Chen A. Mol. Cell. Biol. 2000; PubMed Scopus Google Scholar). In SKIP and Ski/Sno opposing transcriptional the that the cellular of Ski or Sno a TGF-β-dependent transcription and its cell growth and the domain of SKIP appears to also involved in interaction with Ski and Sno. and M. J. results and that like Ski/Sno, interacted with the MH2 domain of Smad3 suggest that the opposing transcriptional of SKIP and Ski/Sno involve for Smad3 between SKIP and and/or other Smad3 MH2-interacting factors, such as with S. Inoue H. Hanai J. Kusanagi K. Nemoto N. Miyazono K. Kawabata M. J. Biol. Chem. 1999; 274: 35269-35277Abstract Full Text Full Text PDF PubMed Scopus (335) Google Scholar, Y. R. Genes Dev. 1998; 12: PubMed Scopus Google Scholar, R. T. Genes Dev. 1998; 12: PubMed Scopus Google Scholar). Thus, the of SKIP through the MH2 domain the and of transcriptional as SKIP and Ski/Sno interact with other and also with the related an mechanism involve (1Massague J. Wotton D. EMBO J. 2000; 19: 1745-1754Crossref PubMed Google Scholar, K.X. Stroschein S.L. Wang W. Chen D. Martens E. Zhou S. Zhou Q. Genes Dev. 1999; 13: 2196-2206Crossref PubMed Scopus (389) Google Scholar, R. B. 1998; 16: PubMed Scopus Google Scholar, M. Chen A. Mol. Cell. Biol. 2000; PubMed Scopus Google Scholar). via SKIP of such as or from the Ski/Sno a mechanism to that for and Chen D. J. Biol. Chem. 1999; 274: Full Text Full Text PDF PubMed Scopus Google Scholar). the mechanism of SKIP it that SKIP a in of this cellular and signaling In results a in which SKIP and with other MH2-interacting factors, such as c-Ski and to the transcriptional of a TGF-β-responsive target a potential for SKIP in the regulation of TGF-β cell growth and and Weinberg for and for of the and Fong and other members of the for and