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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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Yokoyama T, Kuga T, Itoh Y, Otake S, Omata C, Saitoh M, Miyazawa K. Smad2Δexon3 and Smad3 have distinct properties in signal transmission leading to TGF-β-induced cell motility. J Biol Chem 2022; 299:102820. [PMID: 36549646 PMCID: PMC9852702 DOI: 10.1016/j.jbc.2022.102820] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 12/11/2022] [Indexed: 12/24/2022] Open
Abstract
In mammalian cells, Smad2 and Smad3, two receptor-regulated Smad proteins, play crucial roles in the signal transmission of transforming growth factor-β (TGF-β) and are involved in various cell regulatory processes, including epithelial-mesenchymal transition-associated cell responses, that is, cell morphological changes, E-cadherin downregulation, stress fiber formation, and cell motility enhancement. Smad2 contains an additional exon encoding 30 amino acid residues compared with Smad3, leading to distinct Smad2 and Smad3 functional properties. Intriguingly, Smad2 also has an alternatively spliced isoform termed Smad2Δexon3 (also known as Smad2β) lacking the additional exon and behaving similarly to Smad3. However, Smad2Δexon3 and Smad3 signaling properties have not yet been compared in detail. In this study, we reveal that Smad2Δexon3 rescues multiple TGF-β-induced in vitro cellular responses that would become defective upon SMAD3 KO but does not rescue cell motility enhancement. Using Smad2Δexon3/Smad3 chimeric proteins, we identified that residues Arg-104 and Asn-210 in Smad3, which are not conserved in Smad2Δexon3, are key for TGF-β-enhanced cell motility. Moreover, we discovered that Smad2Δexon3 fails to rescue the enhanced cell motility as it does not mediate TGF-β signals to downregulate transcription of ARHGAP24, a GTPase-activating protein that targets Rac1. This study reports for the first time distinct signaling properties of Smad2Δexon3 and Smad3.
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Affiliation(s)
- Takashi Yokoyama
- Department of Biochemistry, Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Takahito Kuga
- Department of Biochemistry, Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan,Research Training Program for Undergraduates, Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Yuka Itoh
- Department of Biochemistry, Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Shigeo Otake
- Department of Biochemistry, Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Chiho Omata
- Department of Biochemistry, Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Masao Saitoh
- Department of Biochemistry, Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan,Center for Medical Education and Science, Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Keiji Miyazawa
- Department of Biochemistry, Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan.
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Gomes T, Martin-Malpartida P, Ruiz L, Aragón E, Cordeiro TN, Macias MJ. Conformational landscape of multidomain SMAD proteins. Comput Struct Biotechnol J 2021; 19:5210-5224. [PMID: 34630939 PMCID: PMC8479633 DOI: 10.1016/j.csbj.2021.09.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 09/08/2021] [Accepted: 09/09/2021] [Indexed: 12/21/2022] Open
Abstract
SMAD transcription factors, the main effectors of the TGFβ (transforming growth factor β) network, have a mixed architecture of globular domains and flexible linkers. Such a complicated architecture precluded the description of their full-length (FL) structure for many years. In this study, we unravel the structures of SMAD4 and SMAD2 proteins through an integrative approach combining Small-angle X-ray scattering, Nuclear Magnetic Resonance spectroscopy, X-ray, and computational modeling. We show that both proteins populate ensembles of conformations, with the globular domains tethered by disordered and flexible linkers, which defines a new dimension of regulation. The flexibility of the linkers facilitates DNA and protein binding and modulates the protein structure. Yet, SMAD4FL is monomeric, whereas SMAD2FL is in different monomer-dimer-trimer states, driven by interactions of the MH2 domains. Dimers are present regardless of the SMAD2FL activation state and concentration. Finally, we propose that SMAD2FL dimers are key building blocks for the quaternary structures of SMAD complexes.
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Affiliation(s)
- Tiago Gomes
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, Barcelona 08028, Spain
| | - Pau Martin-Malpartida
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, Barcelona 08028, Spain
| | - Lidia Ruiz
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, Barcelona 08028, Spain
| | - Eric Aragón
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, Barcelona 08028, Spain
| | - Tiago N. Cordeiro
- Instituto de Tecnologia Química e Biológica António Xavier (ITQB), Universidade NOVA de Lisboa, Av. da República, 2780-157 Oeiras, Portugal
| | - Maria J. Macias
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Baldiri Reixac, 10, Barcelona 08028, Spain
- ICREA, Passeig Lluís Companys 23, Barcelona 08010, Spain
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Uchibe K, Son J, Larmour C, Pacifici M, Enomoto-Iwamoto M, Iwamoto M. Genetic and pharmacological inhibition of retinoic acid receptor γ function promotes endochondral bone formation. J Orthop Res 2017; 35:1096-1105. [PMID: 27325507 PMCID: PMC6900928 DOI: 10.1002/jor.23347] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Accepted: 06/14/2016] [Indexed: 02/04/2023]
Abstract
The nuclear retinoic acid receptors (RARs) play key roles in skeletal development and endochondral ossification. Previously, we showed that RARγ regulates chondrogenesis and that pharmacological activation of RARγ blocked heterotopic ossification (HO), pathology in which endochondral bone forms in soft tissues. Thus, we reasoned that pharmacological inhibition of RARγ should enhance endochondral ossification, leading to a potential therapeutic strategy for bone deficiencies. We created surgical bone defects in wild type and RARγ-null mice and monitored bone healing. Fibrous, cartilaginous, and osseous tissues formed in both groups by day 7, but more cartilaginous tissue formed in mutants within and around the defects compared to controls. Next, we implanted a mixture of Matrigel and rhBMP2 subdermally to induce ectopic endochondral ossification. Administration of RARγ antagonists significantly stimulated ectopic bone formation in wild type but not in RARγ-null mice. The antagonist-induced increases in bone formation were preceded by increases in cartilage formation and were accompanied by higher levels of phosphorylated Smad1/5/8 (pSmad1/5/8) compared to vehicle-treated control. Higher pSmad1/5/8 levels were also observed in cartilaginous tissues forming in healing bone defects in RARγ-null mice, and increases in pSmad1/5/8 levels and Id1-luc activity were observed in RARγ antagonist-treated chondrogenic cells in culture. Our data show that genetic or pharmacological interference with RARγ stimulates endochondral bone formation and does so at least in part by stimulating canonical BMP signaling. This pharmacologic strategy could represent a new tool to enhance endochondral bone formation in the setting of various orthopedic surgical interventions and other skeletal deficiencies. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1096-1105, 2017.
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Affiliation(s)
- Kenta Uchibe
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, Philadelphia, PA
- Department of Oral Morphology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Jiyeon Son
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, Philadelphia, PA
| | - Colleen Larmour
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, Philadelphia, PA
| | - Maurizio Pacifici
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, Philadelphia, PA
| | - Motomi Enomoto-Iwamoto
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, Philadelphia, PA
| | - Masahiro Iwamoto
- Translational Research Program in Pediatric Orthopaedics, Division of Orthopaedic Surgery, The Children’s Hospital of Philadelphia, Philadelphia, PA
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Babonis LS, Martindale MQ. Phylogenetic evidence for the modular evolution of metazoan signalling pathways. Philos Trans R Soc Lond B Biol Sci 2017; 372:20150477. [PMID: 27994120 PMCID: PMC5182411 DOI: 10.1098/rstb.2015.0477] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/03/2016] [Indexed: 12/12/2022] Open
Abstract
Communication among cells was paramount to the evolutionary increase in cell type diversity and, ultimately, the origin of large body size. Across the diversity of Metazoa, there are only few conserved cell signalling pathways known to orchestrate the complex cell and tissue interactions regulating development; thus, modification to these few pathways has been responsible for generating diversity during the evolution of animals. Here, we summarize evidence for the origin and putative function of the intracellular, membrane-bound and secreted components of seven metazoan cell signalling pathways with a special focus on early branching metazoans (ctenophores, poriferans, placozoans and cnidarians) and basal unikonts (amoebozoans, fungi, filastereans and choanoflagellates). We highlight the modular incorporation of intra- and extracellular components in each signalling pathway and suggest that increases in the complexity of the extracellular matrix may have further promoted the modulation of cell signalling during metazoan evolution. Most importantly, this updated view of metazoan signalling pathways highlights the need for explicit study of canonical signalling pathway components in taxa that do not operate a complete signalling pathway. Studies like these are critical for developing a deeper understanding of the evolution of cell signalling.This article is part of the themed issue 'Evo-devo in the genomics era, and the origins of morphological diversity'.
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Affiliation(s)
- Leslie S Babonis
- Whitney Lab for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
| | - Mark Q Martindale
- Whitney Lab for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA
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