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Miyazawa K, Itoh Y, Fu H, Miyazono K. Receptor-activated transcription factors and beyond: multiple modes of Smad2/3-dependent transmission of TGF-β signaling. J Biol Chem 2024; 300:107256. [PMID: 38569937 PMCID: PMC11063908 DOI: 10.1016/j.jbc.2024.107256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 02/28/2024] [Accepted: 03/05/2024] [Indexed: 04/05/2024] Open
Abstract
Transforming growth factor β (TGF-β) is a pleiotropic cytokine that is widely distributed throughout the body. Its receptor proteins, TGF-β type I and type II receptors, are also ubiquitously expressed. Therefore, the regulation of various signaling outputs in a context-dependent manner is a critical issue in this field. Smad proteins were originally identified as signal-activated transcription factors similar to signal transducer and activator of transcription proteins. Smads are activated by serine phosphorylation mediated by intrinsic receptor dual specificity kinases of the TGF-β family, indicating that Smads are receptor-restricted effector molecules downstream of ligands of the TGF-β family. Smad proteins have other functions in addition to transcriptional regulation, including post-transcriptional regulation of micro-RNA processing, pre-mRNA splicing, and m6A methylation. Recent technical advances have identified a novel landscape of Smad-dependent signal transduction, including regulation of mitochondrial function without involving regulation of gene expression. Therefore, Smad proteins are receptor-activated transcription factors and also act as intracellular signaling modulators with multiple modes of function. In this review, we discuss the role of Smad proteins as receptor-activated transcription factors and beyond. We also describe the functional differences between Smad2 and Smad3, two receptor-activated Smad proteins downstream of TGF-β, activin, myostatin, growth and differentiation factor (GDF) 11, and Nodal.
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Affiliation(s)
- Keiji Miyazawa
- Department of Biochemistry, Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan.
| | - Yuka Itoh
- Department of Biochemistry, Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Hao Fu
- Department of Biochemistry, Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Kohei Miyazono
- Department of Applied Pathology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; Laboratory for Cancer Invasion and Metastasis, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
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Ishii S, Fujiwara T, Yagi H, Takeda N, Ando M, Yamauchi H, Inuzuka R, Taniguchi Y, Hatano M, Komuro I. A novel pathogenic variant located just upstream of the C-terminal Ser423-X-Ser425 phosphorylation motif in SMAD3 causing Loeys-Dietz syndrome. Mol Genet Genomic Med 2023; 11:e2257. [PMID: 37864304 PMCID: PMC10724497 DOI: 10.1002/mgg3.2257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 04/21/2023] [Accepted: 07/14/2023] [Indexed: 10/22/2023] Open
Abstract
OBJECTIVE Loeys-Dietz syndrome (LDS) is a heritable disorder of connective tissue closely related to Marfan syndrome (MFS). LDS is caused by loss-of-function variants of genes that encode components of transforming growth factor-β (TGF-β) signaling; nevertheless, LDS type 1/2 caused by TGFBR1/2 pathogenic variants is frequently found to have paradoxical increases in TGF-β signaling in the aneurysmal aortic wall. Here, we present a Japanese LDS family having a novel SMAD3 variant. METHODS The proband was tested via clinical, genetic, and histological analyses. In vitro analysis was performed for pathogenic evaluation. RESULTS The novel heterozygous missense variant of SMAD3 [c.1262G>A, p.(Cys421Tyr)], located just upstream of the C-terminal Ser423-X-Ser425 phosphorylation motif, was found in this instance of LDS type 3. This variant led to reduced phospho-SMAD3 (Ser423/Ser425) levels and transcription activity in vitro; however, a paradoxical upregulation of TGF-β signaling was evident in the aortic wall. CONCLUSIONS Our results revealed the presence of TGF-β paradox in this case with the novel loss-of-function SMAD3 variant. The precise mechanism underlying the paradox is unknown, but further research is warranted to clarify the influence of the SMAD3 variant type and location on the LDS3 phenotype as well as the molecular mechanism leading to LDS3 aortopathy.
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Affiliation(s)
- Satoshi Ishii
- Department of Cardiovascular MedicineThe University of Tokyo HospitalTokyoJapan
| | - Takayuki Fujiwara
- Department of Cardiovascular MedicineThe University of Tokyo HospitalTokyoJapan
- Department of Computational Diagnostic Radiology and Preventive MedicineThe University of Tokyo HospitalTokyoJapan
| | - Hiroki Yagi
- Department of Cardiovascular MedicineThe University of Tokyo HospitalTokyoJapan
- Marfan Syndrome CenterThe University of Tokyo HospitalTokyoJapan
| | - Norifumi Takeda
- Department of Cardiovascular MedicineThe University of Tokyo HospitalTokyoJapan
- Marfan Syndrome CenterThe University of Tokyo HospitalTokyoJapan
| | - Masahiko Ando
- Marfan Syndrome CenterThe University of Tokyo HospitalTokyoJapan
- Department of Cardiac SurgeryThe University of Tokyo HospitalTokyoJapan
| | - Haruo Yamauchi
- Marfan Syndrome CenterThe University of Tokyo HospitalTokyoJapan
- Department of Cardiac SurgeryThe University of Tokyo HospitalTokyoJapan
| | - Ryo Inuzuka
- Marfan Syndrome CenterThe University of Tokyo HospitalTokyoJapan
- Department of PediatricsThe University of Tokyo HospitalTokyoJapan
| | - Yuki Taniguchi
- Marfan Syndrome CenterThe University of Tokyo HospitalTokyoJapan
- Department of Orthopedic SurgeryThe University of Tokyo HospitalTokyoJapan
| | - Masaru Hatano
- Department of Cardiovascular MedicineThe University of Tokyo HospitalTokyoJapan
- Department of Advanced Medical Center for Heart FailureThe University of Tokyo HospitalTokyoJapan
| | - Issei Komuro
- Department of Cardiovascular MedicineThe University of Tokyo HospitalTokyoJapan
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Abstract
An unresolved question critical for understanding cancer is how recurring somatic mutations are retained and how selective pressures drive retention. Increased intracellular pH (pHi) is common to most cancers and is an early event in cancer development. Recent work shows that recurrent somatic mutations can confer an adaptive gain in pH sensing to mutant proteins, enhancing tumorigenic phenotypes specifically at the increased pHi of cancer. Newly identified amino acid mutation signatures in cancer suggest charge-changing mutations define and shape the mutational landscape of cancer. Taken together, these results support a new perspective on the functional significance of somatic mutations in cancer. In this review, we explore existing data and new directions for better understanding how changes in dynamic pH sensing by somatic mutation might be conferring a fitness advantage to the high pH of cancer.
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Nolan BE, Levenson E, Chen BY. Influential Mutations in the SMAD4 Trimer Complex Can Be Detected from Disruptions of Electrostatic Complementarity. J Comput Biol 2018; 24:68-78. [PMID: 28051901 DOI: 10.1089/cmb.2016.0162] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
This article examines three techniques for rapidly assessing the electrostatic contribution of individual amino acids to the stability of protein-protein complexes. Whereas the energetic minimization of modeled oligomers may yield more accurate complexes, we examined the possibility that simple modeling may be sufficient to identify amino acids that add to or detract from electrostatic complementarity. The three methods evaluated were (a) the elimination of entire side chains (e.g., glycine scanning), (b) the elimination of the electrostatic contribution from the atoms of a side chain, called nullification, and (c) side chain structure prediction using SCWRL4. These techniques generate models in seconds, enabling large-scale mutational scanning. We evaluated these techniques on the SMAD2/SMAD4 heterotrimer, whose formation plays a crucial role in antitumor pathways. Many studies have documented the clinical and structural effect of specific mutations on trimer formation. Our results describe how glycine scanning yields more specific predictions, although nullification may be more sensitive, and how side chain structure prediction enables the identification of uncharged-to-charge mutations.
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Affiliation(s)
- Bridget E Nolan
- Department of Computer Science and Engineering, Lehigh University , Bethlehem, Pennsylvania
| | - Emily Levenson
- Department of Computer Science and Engineering, Lehigh University , Bethlehem, Pennsylvania
| | - Brian Y Chen
- Department of Computer Science and Engineering, Lehigh University , Bethlehem, Pennsylvania
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Wang Y, He H, Liyanarachchi S, Genutis LK, Li W, Yu L, Phay JE, Shen R, Brock P, de la Chapelle A. The role of SMAD3 in the genetic predisposition to papillary thyroid carcinoma. Genet Med 2018; 20:927-935. [PMID: 29300379 DOI: 10.1038/gim.2017.224] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 10/25/2017] [Indexed: 02/07/2023] Open
Abstract
PURPOSE To identify and characterize the functional variants, regulatory gene networks, and potential binding targets of SMAD3 in the 15q22 thyroid cancer risk locus. METHODS We performed linkage disequilibrium (LD) and haplotype analyses to fine map the 15q22 locus. Luciferase reporter assays were applied to evaluate the regulatory effects of the candidate variants. Knockdown by small interfering RNA, microarray analysis, chromatin immunoprecipitation (ChIP) and quantitative real-time polymerase chain reaction assays were performed to reveal the regulatory gene network and identify its binding targets. RESULTS We report a 25.6-kb haplotype within SMAD3 containing numerous single-nucleotide polymorphisms (SNPs) in high LD. SNPs rs17293632 and rs4562997 were identified as functional variants of SMAD3 by luciferase assays within the LD region. These variants regulate SMAD3 transcription in an allele-specific manner through enhancer elements in introns of SMAD3. Knockdown of SMAD3 in thyroid cancer cell lines revealed its regulatory gene network including two upregulated genes, SPRY4 and SPRY4-IT1. Sequence analysis and ChIP assays validated the actual binding of SMAD3 protein to multiple SMAD binding element sites in the region upstream of SPRY4. CONCLUSION Our data provide a functional annotation of the 15q22 thyroid cancer risk locus.
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Affiliation(s)
- Yanqiang Wang
- Human Cancer Genetics Program and Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, USA
| | - Huiling He
- Human Cancer Genetics Program and Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, USA
| | - Sandya Liyanarachchi
- Human Cancer Genetics Program and Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, USA
| | - Luke K Genutis
- Human Cancer Genetics Program and Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, USA
| | - Wei Li
- Human Cancer Genetics Program and Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, USA
| | - Lianbo Yu
- Center for Biostatistics, The Ohio State University, Columbus, Ohio, USA.,Department of Biomedical Informatics, The Ohio State University, Ohio, Columbus, USA
| | - John E Phay
- Department of Surgery, The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, USA
| | - Rulong Shen
- Department of Pathology, The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, USA
| | - Pamela Brock
- Department of Internal Medicine, The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, USA
| | - Albert de la Chapelle
- Human Cancer Genetics Program and Department of Cancer Biology and Genetics, The Ohio State University Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio, USA.
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Yu Q, Shi X, Greer T, Lietz CB, Kent KC, Li L. Evaluation and Application of Dimethylated Amino Acids as Isobaric Tags for Quantitative Proteomics of the TGF-β/Smad3 Signaling Pathway. J Proteome Res 2016; 15:3420-31. [PMID: 27457343 DOI: 10.1021/acs.jproteome.6b00641] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Isobaric labeling has become a widespread tool for quantitative proteomic studies. Here, we report the development and evaluation of several dimethylated amino acids as novel isobaric tags for quantitative proteomics. Four-plex dimethylated alanine (DiAla), valine (DiVal), and leucine (DiLeu) have been synthesized, sharing common features of peptide tagging and reporter ion production. DiAla and DiLeu are shown to achieve complete labeling. These two tags' impacts on peptide fragmentation and quantitation are further evaluated using HEK293 cell lysate. DiAla labeling generates more abundant backbone fragmentation whereas DiLeu labeling produces more intense reporter ions. Nonetheless, both tags enable accurate quantitative analysis of HEK293 cell proteomes. DiAla and DiLeu tags are then applied to study the TGF-β/Smad3 pathway with four differentially treated mouse vascular smooth muscle (MOVAS) cells. Our MS data reveal proteome-wide changes of AdSmad3 as compared to the GFP control, consistent with previous findings of causing smooth muscle cell (SMC) dedifferentiation.1 Additionally, the other two novel mutations on the hub protein Smad3, Y226A, and D408H, show compromised TGF-β/Smad3-dependent gene transcription and reversed phenotypic switch. These results are further corroborated with Western blotting and demonstrate that the novel DiAla and DiLeu isobaric tagging reagents provide useful tools for multiplex quantitative proteomics.
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Affiliation(s)
- Qing Yu
- School of Pharmacy, University of Wisconsin , Madison, Wisconsin 53705, United States
| | - Xudong Shi
- Department of Surgery, School of Medicine and Public Health, University of Wisconsin , Madison, Wisconsin 53705, United States
| | - Tyler Greer
- Department of Chemistry, University of Wisconsin , Madison, Wisconsin 53706, United States
| | - Christopher B Lietz
- Department of Chemistry, University of Wisconsin , Madison, Wisconsin 53706, United States
| | - K Craig Kent
- Department of Surgery, School of Medicine and Public Health, University of Wisconsin , Madison, Wisconsin 53705, United States
| | - Lingjun Li
- School of Pharmacy, University of Wisconsin , Madison, Wisconsin 53705, United States.,Department of Chemistry, University of Wisconsin , Madison, Wisconsin 53706, United States
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Cukuroglu E, Engin HB, Gursoy A, Keskin O. Hot spots in protein–protein interfaces: Towards drug discovery. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 116:165-73. [DOI: 10.1016/j.pbiomolbio.2014.06.003] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 05/30/2014] [Accepted: 06/12/2014] [Indexed: 11/16/2022]
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Conidi A, van den Berghe V, Leslie K, Stryjewska A, Xue H, Chen YG, Seuntjens E, Huylebroeck D. Four amino acids within a tandem QxVx repeat in a predicted extended α-helix of the Smad-binding domain of Sip1 are necessary for binding to activated Smad proteins. PLoS One 2013; 8:e76733. [PMID: 24146916 PMCID: PMC3795639 DOI: 10.1371/journal.pone.0076733] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 08/28/2013] [Indexed: 12/20/2022] Open
Abstract
The zinc finger transcription factor Smad-interacting protein-1 (Sip1; Zeb2, Zfhx1b) plays an important role during vertebrate embryogenesis in various tissues and differentiating cell types, and during tumorigenesis. Previous biochemical analysis suggests that interactions with several partner proteins, including TGFβ family receptor-activated Smads, regulate the activities of Sip1 in the nucleus both as a DNA-binding transcriptional repressor and activator. Using a peptide aptamer approach we mapped in Sip1 its Smad-binding domain (SBD), initially defined as a segment of 51 amino acids, to a shorter stretch of 14 amino acids within this SBD. Modelling suggests that this short SBD stretch is part of an extended α-helix that may fit the binding to a hydrophobic corridor within the MH2 domain of activated Smads. Four amino acids (two polar Q residues and two non-polar V residues) that form the tandem repeat (QxVx)2 in this 14-residue stretch were found to be crucial for binding to both TGFβ/Nodal/Activin-Smads and BMP-Smads. A full-length Sip1 with collective mutation of these Q and V residues (to A) no longer binds to Smads, while it retains its binding activity to its cognate bipartite target DNA sequence. This missense mutant Sip1(AxAx)2 provides a new molecular tool to identify SBD (in)dependent target genes in Sip1-controlled TGFβ and/or BMP (de)regulated cellular, developmental and pathological processes.
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Affiliation(s)
- Andrea Conidi
- Laboratory of Molecular Biology (Celgen), Department of Development and Regeneration, Katholieke Universiteit Leuven, Leuven, Belgium
- Department of Cell Biology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Veronique van den Berghe
- Laboratory of Molecular Biology (Celgen), Department of Development and Regeneration, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Kris Leslie
- Department of Cell Biology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Agata Stryjewska
- Laboratory of Molecular Biology (Celgen), Department of Development and Regeneration, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Hua Xue
- The State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua-Beijing Centre for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Ye-Guang Chen
- The State Key Laboratory of Biomembrane and Membrane Biotechnology, Tsinghua-Beijing Centre for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Eve Seuntjens
- Laboratory of Molecular Biology (Celgen), Department of Development and Regeneration, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Danny Huylebroeck
- Laboratory of Molecular Biology (Celgen), Department of Development and Regeneration, Katholieke Universiteit Leuven, Leuven, Belgium
- Department of Cell Biology, Erasmus University Medical Center, Rotterdam, The Netherlands
- * E-mail:
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Goodman CA, McNally RM, Hoffmann FM, Hornberger TA. Smad3 induces atrogin-1, inhibits mTOR and protein synthesis, and promotes muscle atrophy in vivo. Mol Endocrinol 2013; 27:1946-57. [PMID: 24002653 DOI: 10.1210/me.2013-1194] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Myostatin, a member of the TGF superfamily, is sufficient to induce skeletal muscle atrophy. Myostatin-induced atrophy is associated with increases in E3-ligase atrogin-1 expression and protein degradation and decreases in Akt/mechanistic target of rapamycin (mTOR) signaling and protein synthesis. Myostatin signaling activates the transcription factor Smad3 (Small Mothers Against Decapentaplegic), which has been shown to be necessary for myostatin-induced atrogin-1 expression and atrophy; however, it is not known whether Smad3 is sufficient to induce these events or whether Smad3 simply plays a permissive role. Thus, the aim of this study was to address these questions with an in vivo model. To accomplish this goal, in vivo transfection of plasmid DNA was used to create transient transgenic mouse skeletal muscles, and our results show for the first time that Smad3 expression is sufficient to stimulate atrogin-1 promoter activity, inhibit Akt/mTOR signaling and protein synthesis, and induce muscle fiber atrophy. Moreover, we propose that Akt/mTOR signaling is inhibited by a Smad3-induced decrease in microRNA-29 (miR-29) expression and a subsequent increase in the translation of phosphatase and tensin homolog (PTEN) mRNA. Smad3 is also sufficient to inhibit peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α) promoter activity and to increase FoxO (Forkhead Box Protein, Subclass O)-mediated signaling and the promoter activity of plasminogen activator inhibitor 1 (PAI-1). Combined, this study provides the first evidence that Smad3 is sufficient to regulate many of the events associated with myostatin-induced atrophy and therefore suggests that Smad3 signaling may be a viable target for therapies aimed at preventing myostatin-induced muscle atrophy.
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Affiliation(s)
- Craig A Goodman
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, 2015 Linden Drive, Madison, WI 53706.
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Sorrentino GM, Gillis WQ, Oomen-Hajagos J, Thomsen GH. Conservation and evolutionary divergence in the activity of receptor-regulated smads. EvoDevo 2012; 3:22. [PMID: 23020873 PMCID: PMC3500652 DOI: 10.1186/2041-9139-3-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Accepted: 08/09/2012] [Indexed: 01/20/2023] Open
Abstract
Background Activity of the Transforming growth factor-β (TGFβ) pathway is essential to the establishment of body axes and tissue differentiation in bilaterians. Orthologs for core pathway members have been found in all metazoans, but uncertain homology of the body axes and tissues patterned by these signals raises questions about the activities of these molecules across the metazoan tree. We focus on the principal canonical transduction proteins (R-Smads) of the TGFβ pathway, which instruct both axial patterning and tissue differentiation in the developing embryo. We compare the activity of R-Smads from a cnidarian (Nematostella vectensis), an arthropod (Drosophila melanogaster), and a vertebrate (Xenopus laevis) in Xenopus embryonic assays. Results Overexpressing NvSmad1/5 ventralized Xenopus embryos when expressed in dorsal blastomeres, similar to the effects of Xenopus Smad1. However, NvSmad1/5 was less potent than XSmad1 in its ability to activate downstream target genes in Xenopus animal cap assays. NvSmad2/3 strongly induced general mesendodermal marker genes, but weakly induced ones involved in specifying the Spemann organizer. NvSmad2/3 was unable to induce a secondary trunk axis in Xenopus embryos, whereas the orthologs from Xenopus (XSmad2 and XSmad3) and Drosophila (dSmad2) were capable of doing so. Replacement of the NvSmad2/3 MH2 domain with the Xenopus XSmad2 MH2 slightly increased its inductive capability, but did not confer an ability to generate a secondary body axis. Conclusions Vertebrate and cnidarian Smad1/5 have similar axial patterning and induction activities, although NvSmad1/5 is less efficient than the vertebrate gene. We conclude that the activities of Smad1/5 orthologs have been largely conserved across Metazoa. NvSmad2/3 efficiently activates general mesendoderm markers, but is unable to induce vertebrate organizer-specific genes or to produce a secondary body axis in Xenopus. Orthologs dSmad2 and XSmad3 generate a secondary body axis, but activate only low expression of organizer-specific genes that are strongly induced by XSmad2. We suggest that in the vertebrate lineage, Smad2 has evolved a specialized role in the induction of the embryonic organizer. Given the high level of sequence identity between Smad orthologs, this work underscores the functional importance of the emergence and fixation of a few divergent amino acids among orthologs during evolution.
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Affiliation(s)
- Gina M Sorrentino
- Department of Biochemistry and Cell Biology, Stony Brook University, Life Sciences Building room 450, Stony Brook, NY, 11794-5215, USA.
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Zhang P, Cai Y, Soofi A, Dressler GR. Activation of Wnt11 by transforming growth factor-β drives mesenchymal gene expression through non-canonical Wnt protein signaling in renal epithelial cells. J Biol Chem 2012; 287:21290-302. [PMID: 22556418 DOI: 10.1074/jbc.m112.357202] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Transforming growth factor β1 (TGF-β) promotes renal interstitial fibrosis in vivo and the expression of mesenchymal genes in vitro; however, most of its direct targets in epithelial cells are still elusive. In a screen for genes directly activated by TGF-β, we found that components of the Wnt signaling pathway, especially Wnt11, were targets of activation by TGF-β and Smad3 in primary renal epithelial cells. In gain and loss of function experiments, Wnt11 mediated the actions of TGF-β through enhanced activation of mesenchymal marker genes, such as Zeb1, Snail1, Pai1, and αSMA, without affecting Smad3 phosphorylation. Inhibition of Wnt11 by receptor knockdown or treatment with Wnt inhibitors limited the effects of TGF-β on gene expression. We found no evidence that Wnt11 activated the canonical Wnt signaling pathway in renal epithelial cells; rather, the function of Wnt11 was mediated by the c-Jun N-terminal kinase (JNK) pathway. Consistent with the in vitro results, all the TGF-β, Wnt11, and JNK targets were activated in a unilateral ureteral obstruction (UUO) model of renal fibrosis in vivo. Our findings demonstrated cooperativity among the TGF-β, Wnt11, and JNK signaling pathways and suggest new targets for anti-fibrotic therapy in renal tissue.
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Affiliation(s)
- Peng Zhang
- Department of Pathology, University of Michigan, Ann Arbor, Michigan 48109, USA
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