Regulation of Smad signaling through a differential recruitment of coactivators and corepressors by ZEB proteins.
Balancing signals derived from the TGFbeta family is crucial for regulating cell proliferation and differentiation, and in establishing the embryonic axis during development. TGFbeta/BMP signaling leads to the activation and nuclear translocation of Smad proteins, which activate transcription of specific target genes by recruiting P/CAF and p300. The two members of the ZEB family of zinc finger factors (ZEB-1/deltaEF1 and ZEB-2/SIP1) regulate TGFbeta/BMP signaling in opposite ways: ZEB-1/deltaEF1 synergizes with Smad-mediated transcriptional activation, while ZEB-2/SIP1 represses it. Here we report that these antagonistic effects by the ZEB proteins arise from the differential recruitment of transcriptional coactivators (p300 and P/CAF) and corepressors (CtBP) to the Smads. Thus, while ZEB-1/deltaEF1 binds to p300 and promotes the formation of a p300-Smad transcriptional complex, ZEB-2/SIP1 acts as a repressor by recruiting CtBP. This model of regulation by ZEB proteins also functions in vivo, where they have opposing effects on the regulation of TGFbeta family-dependent genes during Xenopus development.
Postigo
Antonio A
AA
Division of Molecular Oncology, Department of Internal Medicine, Washington University School of Medicine, St Louis, MO 63110, USA. apostigo@im.wustl.edu
Depp
Jennifer L
JL
Taylor
Jennifer J
JJ
Kroll
Kristen L
KL
D000429:Alcohol Oxidoreductases; D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004625:Embryo, Nonmammalian / Q000033:anatomy & histology / Q000502:physiology; D005786:Gene Expression Regulation; D018398:Homeodomain Proteins / Q000378:metabolism; D006801:Humans; D017403:In Situ Hybridization; D009687:Nuclear Proteins / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D011485:Protein Binding; D012097:Repressor Proteins / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D051785:Smad Proteins; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D016212:Transforming Growth Factor beta / Q000378:metabolism; D029867:Xenopus Proteins; D014982:Xenopus laevis / Q000254:growth & development / Q000502:physiology; D000074165:Zinc Finger E-box Binding Homeobox 2; D000071799:Zinc Finger E-box-Binding Homeobox 1; D016335:Zinc Fingers
D019485:Bone Morphogenetic Proteins; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D012097:Repressor Proteins; D051785:Smad Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D029867:Xenopus Proteins; C486307:ZEB1 protein, human; C492364:ZEB2 protein, Xenopus; C492363:ZEB2 protein, human; D000074165:Zinc Finger E-box Binding Homeobox 2; D000071799:Zinc Finger E-box-Binding Homeobox 1; D000429:Alcohol Oxidoreductases; C096794:C-terminal binding protein