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Runa F, Ortiz-Soto G, de Barros NR, Kelber JA. Targeting SMAD-Dependent Signaling: Considerations in Epithelial and Mesenchymal Solid Tumors. Pharmaceuticals (Basel) 2024; 17:326. [PMID: 38543112 PMCID: PMC10975212 DOI: 10.3390/ph17030326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 02/19/2024] [Accepted: 02/23/2024] [Indexed: 04/01/2024] Open
Abstract
SMADs are the canonical intracellular effector proteins of the TGF-β (transforming growth factor-β). SMADs translocate from plasma membrane receptors to the nucleus regulated by many SMAD-interacting proteins through phosphorylation and other post-translational modifications that govern their nucleocytoplasmic shuttling and subsequent transcriptional activity. The signaling pathway of TGF-β/SMAD exhibits both tumor-suppressing and tumor-promoting phenotypes in epithelial-derived solid tumors. Collectively, the pleiotropic nature of TGF-β/SMAD signaling presents significant challenges for the development of effective cancer therapies. Here, we review preclinical studies that evaluate the efficacy of inhibitors targeting major SMAD-regulating and/or -interacting proteins, particularly enzymes that may play important roles in epithelial or mesenchymal compartments within solid tumors.
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Affiliation(s)
- Farhana Runa
- Department of Biology, California State University Northridge, Northridge, CA 91330, USA
| | | | | | - Jonathan A Kelber
- Department of Biology, California State University Northridge, Northridge, CA 91330, USA
- Department of Biology, Baylor University, Waco, TX 76706, USA
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2
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Zhou R, Wu Q, Wang M, Irani S, Li X, Zhang Q, Meng F, Liu S, Zhang F, Wu L, Lin X, Wang X, Zou J, Song H, Qin J, Liang T, Feng XH, Zhang YJ, Xu P. The protein phosphatase PPM1A dephosphorylates and activates YAP to govern mammalian intestinal and liver regeneration. PLoS Biol 2021; 19:e3001122. [PMID: 33630828 PMCID: PMC7978383 DOI: 10.1371/journal.pbio.3001122] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 03/19/2021] [Accepted: 01/29/2021] [Indexed: 12/24/2022] Open
Abstract
The Hippo-YAP pathway responds to diverse environmental cues to manage tissue homeostasis, organ regeneration, tumorigenesis, and immunity. However, how phosphatase(s) directly target Yes-associated protein (YAP) and determine its physiological activity are still inconclusive. Here, we utilized an unbiased phosphatome screening and identified protein phosphatase magnesium-dependent 1A (PPM1A/PP2Cα) as the bona fide and physiological YAP phosphatase. We found that PPM1A was associated with YAP/TAZ in both the cytoplasm and the nucleus to directly eliminate phospho-S127 on YAP, which conferring YAP the nuclear distribution and transcription potency. Accordingly, genetic ablation or depletion of PPM1A in cells, organoids, and mice elicited an enhanced YAP/TAZ cytoplasmic retention and resulted in the diminished cell proliferation, severe gut regeneration defects in colitis, and impeded liver regeneration upon injury. These regeneration defects in murine model were largely rescued via a genetic large tumor suppressor kinase 1 (LATS1) deficiency or the pharmacological inhibition of Hippo-YAP signaling. Therefore, we identify a physiological phosphatase of YAP/TAZ, describe its critical effects in YAP/TAZ cellular distribution, and demonstrate its physiological roles in mammalian organ regeneration.
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Affiliation(s)
- Ruyuan Zhou
- MOE Laboratory of Biosystems Homeostasis & Protection, Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China
- Department of Hepatobiliary and Pancreatic Surgery and Zhejiang Provincial Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Qirou Wu
- MOE Laboratory of Biosystems Homeostasis & Protection, Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Mengqiu Wang
- MOE Laboratory of Biosystems Homeostasis & Protection, Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Seema Irani
- Department of Molecular Biosciences; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, United States of America
| | - Xiao Li
- MOE Laboratory of Biosystems Homeostasis & Protection, Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Qian Zhang
- MOE Laboratory of Biosystems Homeostasis & Protection, Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China
- Department of Hepatobiliary and Pancreatic Surgery and Zhejiang Provincial Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Fansen Meng
- MOE Laboratory of Biosystems Homeostasis & Protection, Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China
- Department of Hepatobiliary and Pancreatic Surgery and Zhejiang Provincial Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shengduo Liu
- MOE Laboratory of Biosystems Homeostasis & Protection, Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Fei Zhang
- MOE Laboratory of Biosystems Homeostasis & Protection, Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Liming Wu
- Department of Hepatobiliary and Pancreatic Surgery and Zhejiang Provincial Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xia Lin
- Michael E. DeBakey Department of Surgery and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Xiaojian Wang
- Institute of Immunology, Zhejiang University School of Medicine, Hangzhou, China
| | - Jian Zou
- Eye Center of the Second Affiliated Hospital School of Medicine, Institute of Translational Medicine, Zhejiang University, Hangzhou, China
| | - Hai Song
- MOE Laboratory of Biosystems Homeostasis & Protection, Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China
| | - Jun Qin
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Center for Excellence in Molecular Cell Science, Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China
| | - Tingbo Liang
- Department of Hepatobiliary and Pancreatic Surgery and Zhejiang Provincial Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xin-Hua Feng
- MOE Laboratory of Biosystems Homeostasis & Protection, Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China
- Michael E. DeBakey Department of Surgery and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - Yan Jessie Zhang
- Department of Molecular Biosciences; Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, United States of America
| | - Pinglong Xu
- MOE Laboratory of Biosystems Homeostasis & Protection, Zhejiang Provincial Key Laboratory for Cancer Molecular Cell Biology, Life Sciences Institute, Zhejiang University, Hangzhou, China
- Department of Hepatobiliary and Pancreatic Surgery and Zhejiang Provincial Key Laboratory of Pancreatic Disease, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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3
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Metal-dependent Ser/Thr protein phosphatase PPM family: Evolution, structures, diseases and inhibitors. Pharmacol Ther 2020; 215:107622. [PMID: 32650009 DOI: 10.1016/j.pharmthera.2020.107622] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 06/29/2020] [Indexed: 02/06/2023]
Abstract
Protein phosphatases and kinases control multiple cellular events including proliferation, differentiation, and stress responses through regulating reversible protein phosphorylation, the most important post-translational modification. Members of metal-dependent protein phosphatase (PPM) family, also known as PP2C phosphatases, are Ser/Thr phosphatases that bind manganese/magnesium ions (Mn2+/Mg2+) in their active center and function as single subunit enzymes. In mammals, there are 20 isoforms of PPM phosphatases: PPM1A, PPM1B, PPM1D, PPM1E, PPM1F, PPM1G, PPM1H, PPM1J, PPM1K, PPM1L, PPM1M, PPM1N, ILKAP, PDP1, PDP2, PHLPP1, PHLPP2, PP2D1, PPTC7, and TAB1, whereas there are only 8 in yeast. Phylogenetic analysis of the DNA sequences of vertebrate PPM isoforms revealed that they can be divided into 12 different classes: PPM1A/PPM1B/PPM1N, PPM1D, PPM1E/PPM1F, PPM1G, PPM1H/PPM1J/PPM1M, PPM1K, PPM1L, ILKAP, PDP1/PDP2, PP2D1/PHLPP1/PHLPP2, TAB1, and PPTC7. PPM-family members have a conserved catalytic core region, which contains the metal-chelating residues. The different isoforms also have isoform specific regions within their catalytic core domain and terminal domains, and these regions may be involved in substrate recognition and/or functional regulation of the phosphatases. The twenty mammalian PPM phosphatases are involved in regulating diverse cellular functions, such as cell cycle control, cell differentiation, immune responses, and cell metabolism. Mutation, overexpression, or deletion of the PPM phosphatase gene results in abnormal cellular responses, which lead to various human diseases. This review focuses on the structures and biological functions of the PPM-phosphatase family and their associated diseases. The development of specific inhibitors against the PPM phosphatase family as a therapeutic strategy will also be discussed.
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4
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Brauer BL, Moon TM, Sheftic SR, Nasa I, Page R, Peti W, Kettenbach AN. Leveraging New Definitions of the LxVP SLiM To Discover Novel Calcineurin Regulators and Substrates. ACS Chem Biol 2019; 14:2672-2682. [PMID: 31633908 PMCID: PMC6925343 DOI: 10.1021/acschembio.9b00606] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The Phosphoprotein Phosphatase Calcineurin (CN, PP2B, PP3) recognizes and binds to two short linear motifs (SLiMs), PxIxIT and LxVP, in its regulators and substrates. These interactions enable CN function in many key biological processes. The identification of SLiMs is difficult because of their short, degenerate sequence and often low binding affinity. Here we combine Structure Based Shape Complementarity (SBSC) analysis and proteome-wide affinity purification-mass spectrometry to identify PxIxIT and LxVP containing CN interactors to expand and thereby redefine the LxVP motif. We find that the new πφ-LxVx primary sequence defines an ensemble of binding competent confirmations and thus the binding on-rate, making it difficult to predict the LxVP binding strength from its sequence. Our analysis confirms existing and, more importantly, identifies novel CN interactors, substrates, and thus biological functions of CN.
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Affiliation(s)
- Brooke L. Brauer
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, United States
| | - Thomas M. Moon
- Department of Chemistry and Biochemistry, University of Arizona, 1041 E. Lowell Street, Tucson, Arizona 85721, United States
| | - Sarah R. Sheftic
- Department of Chemistry and Biochemistry, University of Arizona, 1041 E. Lowell Street, Tucson, Arizona 85721, United States
| | - Isha Nasa
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, United States
| | - Rebecca Page
- Department of Chemistry and Biochemistry, University of Arizona, 1041 E. Lowell Street, Tucson, Arizona 85721, United States
| | - Wolfgang Peti
- Department of Chemistry and Biochemistry, University of Arizona, 1041 E. Lowell Street, Tucson, Arizona 85721, United States
| | - Arminja N. Kettenbach
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, United States
- Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire 03756, United States
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5
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Tang W, Zhu Y, Qin W, Zhang H, Zhang H, Lin H, Zhen X, Zhuang X, Tang Y, Jiang H. Ran-binding protein 3 is associated with human spermatogenesis and male infertility. Andrologia 2019; 52:e13446. [PMID: 31833110 DOI: 10.1111/and.13446] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 09/01/2019] [Accepted: 09/05/2019] [Indexed: 11/29/2022] Open
Abstract
Ran-binding protein 3 (RanBP3) is a Ran-interacting protein, which participates in the Ran GTPase system in cancer cell biology. However, the expression pattern and physiological role of RanBP3 remain largely unknown. In this study, we found that RanBP3 was expressed in human testes and localised to spermatogonium and spermatocyte of germ cells. In subcellular structure, its localisation is in the nucleus and cytoplasm. Interestingly, compared with normal groups, RanBP3 expression was lower in groups of patients with Maturation Arrest (MA) and Sertoli cell-only syndrome (SCO) when considered by the Johnson Score. RanBP3 expression in the MA group and SCO groups was dramatically lower than that in the normal control group. Studies have shown that RanBP3, which is one of the helper factors of Ran, is mainly participate in the nucleocytoplasmic transport of cells. RanBP3 helps Ran to achieve some functions such as nucleocytoplasmic transport, spindle assembly during mitosis and nuclear assembly after mitosis. Consequent changes in the expression of RanBP3 may associate with human spermatogenesis disorders and male infertility. The identification and characterisation of RanBP3 enhances our understanding of the molecular mechanisms underpinning its function in human spermatogenesis and male infertility.
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Affiliation(s)
- Wenhao Tang
- Department of Urology, Peking University Third Hospital, Beijing, China.,Department of Reproductive Medicine Center, Peking University Third Hospital, Beijing, China.,Department of Andrology, Peking University Third Hospital, Beijing, China.,Department of Human Sperm Bank, Peking University Third Hospital, Beijing, China
| | - Yutian Zhu
- Department of Urology, Peking University Third Hospital, Beijing, China.,Department of Andrology, Peking University Third Hospital, Beijing, China
| | - Weibing Qin
- Key Laboratory of Male Reproductive and Genetics, National Health and Family Planning Commission (Family Planning Research Institute of Guangdong Province), Guangzhou, China
| | - Haitao Zhang
- Department of Urology, Peking University Third Hospital, Beijing, China.,Department of Reproductive Medicine Center, Peking University Third Hospital, Beijing, China.,Department of Andrology, Peking University Third Hospital, Beijing, China
| | - Hongliang Zhang
- Department of Reproductive Medicine Center, Peking University Third Hospital, Beijing, China.,Department of Andrology, Peking University Third Hospital, Beijing, China.,Department of Human Sperm Bank, Peking University Third Hospital, Beijing, China
| | - Haocheng Lin
- Department of Urology, Peking University Third Hospital, Beijing, China.,Department of Reproductive Medicine Center, Peking University Third Hospital, Beijing, China.,Department of Andrology, Peking University Third Hospital, Beijing, China
| | - Xiumei Zhen
- Department of Reproductive Medicine Center, Peking University Third Hospital, Beijing, China.,Key Laboratory of Assisted Reproduction, Department of Obstetrics and Gynecology, Center for Reproductive Medicine, Ministry of Education, Peking University Third Hospital, Beijing, China
| | - Xinjie Zhuang
- Department of Reproductive Medicine Center, Peking University Third Hospital, Beijing, China.,Key Laboratory of Assisted Reproduction, Department of Obstetrics and Gynecology, Center for Reproductive Medicine, Ministry of Education, Peking University Third Hospital, Beijing, China
| | - Yunge Tang
- Key Laboratory of Male Reproductive and Genetics, National Health and Family Planning Commission (Family Planning Research Institute of Guangdong Province), Guangzhou, China
| | - Hui Jiang
- Department of Urology, Peking University Third Hospital, Beijing, China.,Department of Reproductive Medicine Center, Peking University Third Hospital, Beijing, China.,Department of Andrology, Peking University Third Hospital, Beijing, China.,Department of Human Sperm Bank, Peking University Third Hospital, Beijing, China
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6
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Rotavirus Induces Formation of Remodeled Stress Granules and P Bodies and Their Sequestration in Viroplasms To Promote Progeny Virus Production. J Virol 2018; 92:JVI.01363-18. [PMID: 30258011 DOI: 10.1128/jvi.01363-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 09/20/2018] [Indexed: 02/06/2023] Open
Abstract
Rotavirus replicates in unique virus-induced cytoplasmic inclusion bodies called viroplasms (VMs), the composition and structure of which have yet to be understood. Based on the analysis of a few proteins, earlier studies reported that rotavirus infection inhibits stress granule (SG) formation and disrupts P bodies (PBs). However, the recent demonstration that rotavirus infection induces cytoplasmic relocalization and colocalization with VMs of several nuclear hnRNPs and AU-rich element-binding proteins (ARE-BPs), which are known components of SGs and PBs, suggested the possibility of rotavirus-induced remodeling of SGs and PBs, prompting us to analyze a large number of the SG and PB components to understand the status of SGs and PBs in rotavirus-infected cells. Here we demonstrate that rotavirus infection induces molecular triage by selective exclusion of a few proteins of SGs (G3BP1 and ZBP1) and PBs (DDX6, EDC4, and Pan3) and sequestration of the remodeled/atypical cellular organelles, containing the majority of their components, in the VM. The punctate SG and PB structures are seen at about 4 h postinfection (hpi), coinciding with the appearance of small VMs, many of which fuse to form mature large VMs with progression of infection. By use of small interfering RNA (siRNA)-mediated knockdown and/or ectopic overexpression, the majority of the SG and PB components, except for ADAR1, were observed to inhibit viral protein expression and virus growth. In conclusion, this study demonstrates that VMs are highly complex supramolecular structures and that rotavirus employs a novel strategy of sequestration in the VM and harnessing of the remodeled cellular RNA recycling bins to promote its growth.IMPORTANCE Rotavirus is known to replicate in specialized virus-induced cytoplasmic inclusion bodies called viroplasms (VMs), but the composition and structure of VMs are not yet understood. Here we demonstrate that rotavirus interferes with normal SG and PB assembly but promotes formation of atypical SG-PB structures by selective exclusion of a few components and employs a novel strategy of sequestration of the remodeled SG-PB granules in the VMs to promote virus growth by modulating their negative influence on virus infection. Rotavirus VMs appear to be complex supramolecular structures formed by the union of the triad of viral replication complexes and remodeled SGs and PBs, as well as other host factors, and designed to promote productive virus infection. These observations have implications for the planning of future research with the aim of understanding the structure of the VM, the mechanism of morphogenesis of the virus, and the detailed roles of host proteins in rotavirus biology.
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7
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Han W, Hu P, Wu F, Wang S, Hu Y, Li S, Jiang T, Qiang B, Peng X. FHL3 links cell growth and self-renewal by modulating SOX4 in glioma. Cell Death Differ 2018; 26:796-811. [PMID: 29955125 DOI: 10.1038/s41418-018-0152-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 05/13/2018] [Accepted: 06/05/2018] [Indexed: 12/21/2022] Open
Abstract
Differentiation status significantly affects the properties of malignant glioma cells, with non-stem cells inducing tumor enlargement and stem-like cells driving tumor initiation and treatment resistance. It is not completely understood how the same protein can have a distinct role in these cell populations. Here, we report that four and a half LIM domain protein 3 (FHL3) has an inhibitory effect on proliferation in non-stem glioma cells and a non-proliferative effect in glioma stem cells (GSCs). In GSCs, we show that FHL3 interacts with the Smad2/3 protein complex at the SOX4 promoter region, inhibits SOX4 transcriptional activity by recruiting PPM1A phosphatase to Smad2/3, and then suppresses GSC tumor sphere formation and self-renewal in vitro and in vivo via downregulation of SOX2 expression. Altogether, these findings highlight the role of FHL3 as a stemness-suppressor in regulation of the Smad2/3-SOX4-SOX2 axis in glioma.
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Affiliation(s)
- Wei Han
- State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Medical Primate Research Center, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, 100005, Beijing, China
| | - Peishan Hu
- State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Medical Primate Research Center, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, 100005, Beijing, China
| | - Fan Wu
- State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Medical Primate Research Center, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, 100005, Beijing, China.,Department of Neurosurgery, Beijing Tiantan Hospital, 100050, Beijing, China
| | - Shanshan Wang
- State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Medical Primate Research Center, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, 100005, Beijing, China
| | - Yan Hu
- State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Medical Primate Research Center, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, 100005, Beijing, China
| | - Shanshan Li
- State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Medical Primate Research Center, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, 100005, Beijing, China
| | - Tao Jiang
- Department of Neurosurgery, Beijing Tiantan Hospital, 100050, Beijing, China
| | - Boqin Qiang
- State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Medical Primate Research Center, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, 100005, Beijing, China.
| | - Xiaozhong Peng
- State Key Laboratory of Medical Molecular Biology, Department of Molecular Biology and Biochemistry, Institute of Basic Medical Sciences, Medical Primate Research Center, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine Peking Union Medical College, 100005, Beijing, China. .,Institute of Medical Biology, Chinese Academy of Medical Sciences, Chinese Academy of Medical Science and Peking Union Medical College, 650118, Kunming, China.
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8
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Meeusen B, Janssens V. Tumor suppressive protein phosphatases in human cancer: Emerging targets for therapeutic intervention and tumor stratification. Int J Biochem Cell Biol 2017; 96:98-134. [PMID: 29031806 DOI: 10.1016/j.biocel.2017.10.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 10/04/2017] [Accepted: 10/05/2017] [Indexed: 02/06/2023]
Abstract
Aberrant protein phosphorylation is one of the hallmarks of cancer cells, and in many cases a prerequisite to sustain tumor development and progression. Like protein kinases, protein phosphatases are key regulators of cell signaling. However, their contribution to aberrant signaling in cancer cells is overall less well appreciated, and therefore, their clinical potential remains largely unexploited. In this review, we provide an overview of tumor suppressive protein phosphatases in human cancer. Along their mechanisms of inactivation in defined cancer contexts, we give an overview of their functional roles in diverse signaling pathways that contribute to their tumor suppressive abilities. Finally, we discuss their emerging roles as predictive or prognostic markers, their potential as synthetic lethality targets, and the current feasibility of their reactivation with pharmacologic compounds as promising new cancer therapies. We conclude that their inclusion in clinical practice has obvious potential to significantly improve therapeutic outcome in various ways, and should now definitely be pushed forward.
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Affiliation(s)
- Bob Meeusen
- Laboratory of Protein Phosphorylation & Proteomics, Dept. of Cellular & Molecular Medicine, Faculty of Medicine, KU Leuven & Leuven Cancer Institute (LKI), KU Leuven, Belgium
| | - Veerle Janssens
- Laboratory of Protein Phosphorylation & Proteomics, Dept. of Cellular & Molecular Medicine, Faculty of Medicine, KU Leuven & Leuven Cancer Institute (LKI), KU Leuven, Belgium.
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9
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Wang Y, Feng Q, Ji C, Liu X, Li L, Luo J. RUNX3 plays an important role in mediating the BMP9-induced osteogenic differentiation of mesenchymal stem cells. Int J Mol Med 2017; 40:1991-1999. [PMID: 29039519 DOI: 10.3892/ijmm.2017.3155] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Accepted: 09/08/2017] [Indexed: 11/06/2022] Open
Abstract
Although bone morphogenetic protein 9 (BMP9) is highly capable of promoting the osteogenic differentiation of mesenchymal stem cells (MSCs) both in vitro and in vivo, the molecular mechanisms involved remain to be fully elucidated. Runt-related transcription factor (RUNX)3 is an essential regulator of osteoblast/chondrocyte maturation. However, the exact role of RUNX3 in BMP9 osteoinductive activity is unknown. In this study, we sought to investigate the functional role of RUNX3 in the BMP9-induced osteogenic differentiation of MSCs. We found that BMP9 upregulated the endogenous expression of RUNX3 in MSCs. The overexpression or/and knockdown of RUNX3 both increased the levels of alkaline phosphatase (ALP) a marker of BMP9-induced early osteogenic differentiation. Nevertheless, matrix mineralization, a marker of BMP9-induced late osteogenic differentiation was enhanced by the overexpression of RUNX3, whereas it was inhibited by the knockdown of RUNX3. The BMP9-induced expression of osteogenic pivotal transcription factors [inhibitor of differentiation (Id)3, distal-less homeobox 5 (DLX5) and RUNX2)] was further increased by the overexpression of RUNX3; however, it was reduced by the knockdown of RUNX3. However, the expression levels of Id1 and Id2 were both enhanced by the overexpression or/and knockdown of RUNX3. The BMP9-induced phosphorylation of Smad1/5/8 was increased with the overexpression of RUNX3, and yet was decreased with the knockdown of RUNX3. Collectively, our findings suggest that RUNX3 is an essential modulator of the BMP9-induced osteoblast lineage differentiation of MSCs.
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Affiliation(s)
- Yufeng Wang
- Key Laboratory of Diagnostic Medicine Designated by The Chinese Ministry of Education, Chongqing Medical University, Chongqing 400016, P.R. China
| | - Qiaoling Feng
- Key Laboratory of Diagnostic Medicine Designated by The Chinese Ministry of Education, Chongqing Medical University, Chongqing 400016, P.R. China
| | - Caixia Ji
- Key Laboratory of Diagnostic Medicine Designated by The Chinese Ministry of Education, Chongqing Medical University, Chongqing 400016, P.R. China
| | - Xiaohua Liu
- Key Laboratory of Diagnostic Medicine Designated by The Chinese Ministry of Education, Chongqing Medical University, Chongqing 400016, P.R. China
| | - Li Li
- Key Laboratory of Diagnostic Medicine Designated by The Chinese Ministry of Education, Chongqing Medical University, Chongqing 400016, P.R. China
| | - Jinyong Luo
- Key Laboratory of Diagnostic Medicine Designated by The Chinese Ministry of Education, Chongqing Medical University, Chongqing 400016, P.R. China
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10
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Koyama M, Matsuura Y. Crystal structure of importin-α3 bound to the nuclear localization signal of Ran-binding protein 3. Biochem Biophys Res Commun 2017; 491:609-613. [DOI: 10.1016/j.bbrc.2017.07.155] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 07/27/2017] [Indexed: 12/12/2022]
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11
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Xu P, Lin X, Feng XH. Posttranslational Regulation of Smads. Cold Spring Harb Perspect Biol 2016; 8:cshperspect.a022087. [PMID: 27908935 DOI: 10.1101/cshperspect.a022087] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Transforming growth factor β (TGF-β) family signaling dictates highly complex programs of gene expression responses, which are extensively regulated at multiple levels and vary depending on the physiological context. The formation, activation, and destruction of two major functional complexes in the TGF-β signaling pathway (i.e., the TGF-β receptor complexes and the Smad complexes that act as central mediators of TGF-β signaling) are direct targets for posttranslational regulation. Dysfunction of these complexes often leads or contributes to pathogenesis in cancer and fibrosis and in cardiovascular, and autoimmune diseases. Here we discuss recent insights into the roles of posttranslational modifications in the functions of the receptor-activated Smads in the common Smad4 and inhibitory Smads, and in the control of the physiological responses to TGF-β. It is now evident that these modifications act as decisive factors in defining the intensity and versatility of TGF-β responsiveness. Thus, the characterization of posttranslational modifications of Smads not only sheds light on how TGF-β controls physiological and pathological processes but may also guide us to manipulate the TGF-β responses for therapeutic benefits.
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Affiliation(s)
- Pinglong Xu
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Xia Lin
- Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Texas 77030
| | - Xin-Hua Feng
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang 310058, China.,Michael E. DeBakey Department of Surgery, Baylor College of Medicine, Houston, Texas 77030.,Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, Texas 77030
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12
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Simile MM, Latte G, Demartis MI, Brozzetti S, Calvisi DF, Porcu A, Feo CF, Seddaiu MA, Daino L, Berasain C, Tomasi ML, Avila MA, Feo F, Pascale RM. Post-translational deregulation of YAP1 is genetically controlled in rat liver cancer and determines the fate and stem-like behavior of the human disease. Oncotarget 2016; 7:49194-49216. [PMID: 27359056 PMCID: PMC5226501 DOI: 10.18632/oncotarget.10246] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 05/05/2016] [Indexed: 01/29/2023] Open
Abstract
Previous studies showed that YAP1 is over-expressed in hepatocellular carcinoma (HCC). Here we observed higher expression of Yap1/Ctgf axis in dysplastic nodules and HCC chemically-induced in F344 rats, genetically susceptible to hepatocarcinogenesis, than in lesions induced in resistant BN rats. In BN rats, highest increase in Yap1-tyr357, p73 phosphorylation and Caspase 3 cleavage occurred. In human HCCs with poorer prognosis (< 3 years survival after partial liver resection, HCCP), levels of YAP1, CTGF, 14-3-3, and TEAD proteins, and YAP1-14-3-3 and YAP1-TEAD complexes were higher than in HCCs with better outcome (> 3 years survival; HCCB). In the latter, higher levels of phosphorylated YAP1-ser127, YAP1-tyr357 and p73, YAP1 ubiquitination, and Caspase 3 cleavage occurred. Expression of stemness markers NANOG, OCT-3/4, and CD133 were highest in HCCP and correlated with YAP1 and YAP1-TEAD levels. In HepG2, Huh7, and Hep3B cells, forced YAP1 over-expression led to stem cell markers expression and increased cell viability, whereas inhibition of YAP1 expression by specific siRNA, or transfection of mutant YAP1 which does not bind to TEAD, induced opposite alterations. These changes were associated, in Huh7 cells transfected with YAP1 or YAP1 siRNA, with stimulation or inhibition of cell migration and invasivity, respectively. Furthermore, transcriptome analysis showed that YAP1 transfection in Huh7 cells induces over-expression of genes involved in tumor stemness. In conclusion, Yap1 post-translational modifications favoring its ubiquitination and apoptosis characterize HCC with better prognosis, whereas conditions favoring the formation of YAP1-TEAD complexes are associated with aggressiveness and acquisition of stemness features by HCC cells.
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Affiliation(s)
- Maria M. Simile
- Department of Clinical and Experimental Medicine, Division of Experimental Pathology and Oncology, University of Sassari, Sassari, Italy
| | - Gavinella Latte
- Department of Clinical and Experimental Medicine, Division of Experimental Pathology and Oncology, University of Sassari, Sassari, Italy
| | - Maria I. Demartis
- Department of Clinical and Experimental Medicine, Division of Experimental Pathology and Oncology, University of Sassari, Sassari, Italy
| | - Stefania Brozzetti
- Department of Surgery “Pietro Valdoni”, University of Rome ‘Sapienza’', Rome, Italy
| | - Diego F. Calvisi
- Department of Clinical and Experimental Medicine, Division of Experimental Pathology and Oncology, University of Sassari, Sassari, Italy
| | - Alberto Porcu
- Department of Clinical and Experimental Medicine, Division of Surgery, University of Sassari, Sassari, Italy
| | - Claudio F. Feo
- Department of Clinical and Experimental Medicine, Division of Surgery, University of Sassari, Sassari, Italy
| | - Maria A. Seddaiu
- Department of Clinical and Experimental Medicine, Division of Experimental Pathology and Oncology, University of Sassari, Sassari, Italy
| | - Lucia Daino
- Department of Clinical and Experimental Medicine, Division of Experimental Pathology and Oncology, University of Sassari, Sassari, Italy
| | - Carmen Berasain
- Division of Hepatology, Centro de Investigación Médica Aplicada (CIMA), University of Navarra, Pamplona, Spain
- CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
- IDISNA, Navarra Institute for Health Research, Pamplona, Spain
| | - Maria L. Tomasi
- Division of Gastroenterology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
- USC Research Center for Liver Diseases, Keck School of Medicine of University of Southern California, Los Angeles, CA, USA
| | - Matias A. Avila
- Division of Hepatology, Centro de Investigación Médica Aplicada (CIMA), University of Navarra, Pamplona, Spain
- CIBERehd, Instituto de Salud Carlos III, Madrid, Spain
- IDISNA, Navarra Institute for Health Research, Pamplona, Spain
| | - Francesco Feo
- Department of Clinical and Experimental Medicine, Division of Experimental Pathology and Oncology, University of Sassari, Sassari, Italy
| | - Rosa M. Pascale
- Department of Clinical and Experimental Medicine, Division of Experimental Pathology and Oncology, University of Sassari, Sassari, Italy
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13
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Xiang W, Zhang Q, Lin X, Wu S, Zhou Y, Meng F, Fan Y, Shen T, Xiao M, Xia Z, Zou J, Feng XH, Xu P. PPM1A silences cytosolic RNA sensing and antiviral defense through direct dephosphorylation of MAVS and TBK1. SCIENCE ADVANCES 2016; 2:e1501889. [PMID: 27419230 PMCID: PMC4942338 DOI: 10.1126/sciadv.1501889] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 05/31/2016] [Indexed: 05/20/2023]
Abstract
Cytosolic RNA sensing is a prerequisite for initiation of innate immune response against RNA viral pathogens. Signaling through RIG-I (retinoic acid-inducible gene I)-like receptors (RLRs) to TBK1 (Tank-binding kinase 1)/IKKε (IκB kinase ε) kinases is transduced by mitochondria-associated MAVS (mitochondrial antiviral signaling protein). However, the precise mechanism of how MAVS-mediated TBK1/IKKε activation is strictly controlled still remains obscure. We reported that protein phosphatase magnesium-dependent 1A (PPM1A; also known as PP2Cα), depending on its catalytic ability, dampened the RLR-IRF3 (interferon regulatory factor 3) axis to silence cytosolic RNA sensing signaling. We demonstrated that PPM1A was an inherent partner of the TBK1/IKKε complex, targeted both MAVS and TBK1/IKKε for dephosphorylation, and thus disrupted MAVS-driven formation of signaling complex. Conversely, a high level of MAVS can dissociate the TBK1/PPM1A complex to override PPM1A-mediated inhibition. Loss of PPM1A through gene ablation in human embryonic kidney 293 cells and mouse primary macrophages enabled robustly enhanced antiviral responses. Consequently, Ppm1a(-/-) mice resisted to RNA virus attack, and transgenic zebrafish expressing PPM1A displayed profoundly increased RNA virus vulnerability. These findings identify PPM1A as the first known phosphatase of MAVS and elucidate the physiological function of PPM1A in antiviral immunity on whole animals.
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Affiliation(s)
- Weiwen Xiang
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou 310058, China
| | - Qian Zhang
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou 310058, China
| | - Xia Lin
- Michael E. DeBakey Department of Surgery and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Shiying Wu
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou 310058, China
| | - Yao Zhou
- Eye Center of the Second Affiliated Hospital School of Medicine, Institute of Translational Medicine, Zhejiang University, Hangzhou 310058, China
| | - Fansen Meng
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou 310058, China
| | - Yunyun Fan
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou 310058, China
| | - Tao Shen
- Michael E. DeBakey Department of Surgery and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Mu Xiao
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou 310058, China
| | - Zongping Xia
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou 310058, China
| | - Jian Zou
- Eye Center of the Second Affiliated Hospital School of Medicine, Institute of Translational Medicine, Zhejiang University, Hangzhou 310058, China
| | - Xin-Hua Feng
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou 310058, China
- Michael E. DeBakey Department of Surgery and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
- Corresponding author. (X.-H.F.); (P.X.)
| | - Pinglong Xu
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou 310058, China
- Corresponding author. (X.-H.F.); (P.X.)
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14
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Liu X, Chen Z, Ouyang G, Song T, Liang H, Liu W, Xiao W. ELL Protein-associated Factor 2 (EAF2) Inhibits Transforming Growth Factor β Signaling through a Direct Interaction with Smad3. J Biol Chem 2015; 290:25933-45. [PMID: 26370086 DOI: 10.1074/jbc.m115.663542] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Indexed: 12/29/2022] Open
Abstract
A series of in vitro and in vivo studies has shown that EAF2 can affect multiple signaling pathways involved in cellular processes. However, the molecular mechanisms underlying its effects have remained elusive. Here we report the discovery of a new functional link between EAF2 and TGF-β signaling. Promoter reporter assays indicated that EAF2 suppresses Smad3 transcriptional activity, resulting in inhibition of TGF-β signaling. Coimmunoprecipitation assays showed that EAF2 specifically interacts with Smad3 in vitro and in vivo but not with other Smad proteins. In addition, we observed that EAF2 binding does not alter Smad3 phosphorylation but causes Smad3 cytoplasmic retention, competes with Smad4 for binding to Smad3, and prevents p300-Smad3 complex formation. Furthermore, we demonstrated that EAF2 suppresses both TGF-β-induced G1 cell cycle arrest and TGF-β-induced cell migration. This study identifies and characterizes a novel repressor of TGF-β signaling.
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Affiliation(s)
- Xing Liu
- From the Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Zhu Chen
- From the Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China, Department of Reproduction, Maternal and Child Health Hospital of Hubei Province, Wuhan 430070, China
| | - Gang Ouyang
- From the Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Tieshan Song
- Hubei University of Science and Technology, Xianning 437100, China, and
| | - Huageng Liang
- Department of Urology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Wei Liu
- From the Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Wuhan Xiao
- From the Key Laboratory of Aquatic Biodiversity and Conservation, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China,
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15
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Du ZP, Wu BL, Xie JJ, Lin XH, Qiu XY, Zhan XF, Wang SH, Shen JH, Li EM, Xu LY. Network Analyses of Gene Expression following Fascin Knockdown in Esophageal Squamous Cell Carcinoma Cells. Asian Pac J Cancer Prev 2015. [DOI: 10.7314/apjcp.2015.16.13.5445] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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16
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Nuclear Export of Smads by RanBP3L Regulates Bone Morphogenetic Protein Signaling and Mesenchymal Stem Cell Differentiation. Mol Cell Biol 2015; 35:1700-11. [PMID: 25755279 DOI: 10.1128/mcb.00121-15] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 02/08/2015] [Indexed: 01/08/2023] Open
Abstract
Bone morphogenetic proteins (BMPs) play vital roles in regulating stem cell maintenance and differentiation. BMPs can induce osteogenesis and inhibit myogenesis of mesenchymal stem cells. Canonical BMP signaling is stringently controlled through reversible phosphorylation and nucleocytoplasmic shuttling of Smad1, Smad5, and Smad8 (Smad1/5/8). However, how the nuclear export of Smad1/5/8 is regulated remains unclear. Here we report that the Ran-binding protein RanBP3L acts as a nuclear export factor for Smad1/5/8. RanBP3L directly recognizes dephosphorylated Smad1/5/8 and mediates their nuclear export in a Ran-dependent manner. Increased expression of RanBP3L blocks BMP-induced osteogenesis of mouse bone marrow-derived mesenchymal stem cells and promotes myogenic induction of C2C12 mouse myoblasts, whereas depletion of RanBP3L expression enhances BMP-dependent stem cell differentiation activity and transcriptional responses. In conclusion, our results demonstrate that RanBP3L, as a nuclear exporter for BMP-specific Smads, plays a critical role in terminating BMP signaling and regulating mesenchymal stem cell differentiation.
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Bourgeois B, Gilquin B, Tellier-Lebègue C, Östlund C, Wu W, Pérez J, El Hage P, Lallemand F, Worman HJ, Zinn-Justin S. Inhibition of TGF-β signaling at the nuclear envelope: characterization of interactions between MAN1, Smad2 and Smad3, and PPM1A. Sci Signal 2013; 6:ra49. [PMID: 23779087 DOI: 10.1126/scisignal.2003411] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Signaling by transforming growth factor-β (TGF-β) is critical for various developmental processes and culminates in the activation of the transcription factors Smad2 and Smad3. MAN1, an integral protein of the inner nuclear membrane, inhibits TGF-β signaling by binding to Smad2 and Smad3. Depletion of the gene LEMD3 encoding MAN1 leads to developmental anomalies in mice, and heterozygous loss-of-function mutations in LEMD3 in humans cause sclerosing bone dysplasia. We modeled the three-dimensional structure of the MAN1-Smad2 complex from nuclear magnetic resonance and small-angle x-ray scattering data. As predicted by this model, we found that MAN1 competed in vitro and in cells with the transcription factor FAST1 (forkhead activin signal transducer 1) for binding to Smad2. The model further predicted that MAN1 bound to activated Smad2-Smad4 or Smad3-Smad4 complexes, which was confirmed by in vitro experiments; however, in cells, MAN1 bound only to Smad2 and Smad3 and not to the Smad4-containing complexes. Overexpression of MAN1 led to dephosphorylation of Smad2 and Smad3, thus hindering their recognition by Smad4, and MAN1 bound directly in vitro to the phosphatase PPM1A, which catalyzes the dephosphorylation of Smad2/3. These results demonstrate a nuclear envelope-localized mechanism of inactivating TGF-β signaling in which MAN1 competes with transcription factors for binding to Smad2 and Smad3 and facilitates their dephosphorylation by PPM1A.
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Affiliation(s)
- Benjamin Bourgeois
- Laboratoire de Biologie Structurale et Radiobiologie, URA CNRS 2096, CEA Saclay, 91190 Gif-sur-Yvette, France
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18
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N-Myristoylation is essential for protein phosphatases PPM1A and PPM1B to dephosphorylate their physiological substrates in cells. Biochem J 2013; 449:741-9. [PMID: 23088624 DOI: 10.1042/bj20121201] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
PPM [metal-dependent protein phosphatase, formerly called PP2C (protein phosphatase 2C)] family members play essential roles in regulating a variety of signalling pathways. While searching for protein phosphatase(s) that act on AMPK (AMP-activated protein kinase), we found that PPM1A and PPM1B are N-myristoylated and that this modification is essential for their ability to dephosphorylate the α subunit of AMPK (AMPKα) in cells. N-Myristoylation was also required for two other functions of PPM1A and PPM1B in cells. Although a non-myristoylated mutation (G2A) of PPM1A and PPM1B prevented membrane association, this relocalization did not likely cause the decreased activity towards AMPKα. In in vitro experiments, the G2A mutants exhibited reduced activities towards AMPKα, but much higher specific activity against an artificial substrate, PNPP (p-nitrophenyl phosphate), compared with the wild-type counterparts. Taken together, the results of the present study suggest that N-myristoylation of PPM1A and PPM1B plays a key role in recognition of their physiological substrates in cells.
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19
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Fang Y, Chen Y, Yu L, Zheng C, Qi Y, Li Z, Yang Z, Zhang Y, Shi T, Luo J, Liu M. Inhibition of breast cancer metastases by a novel inhibitor of TGFβ receptor 1. J Natl Cancer Inst 2012. [PMID: 23178439 DOI: 10.1093/jnci/djs485] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Transforming growth factor beta (TGFβ), which is implicated in metastasis to various organs in breast cancer, is a potential target for new antitumor metastasis drugs. METHODS To identify specific inhibitors of TGFβ receptor 1 (TGFβR1) in breast cancer metastasis, a virtual library of more than 400000 different compounds was screened by molecular docking modeling and confirmed with Smad-binding element luciferase and TGFβR1 kinase assays. Affymetrix GeneChip expression analysis of mRNA levels and real-time polymerase chain reaction were performed to determine expression changes of TGFβ-mediated, metastasis-associated genes in breast cancer cells after treatment with the small-molecule inhibitor YR-290. YR-290 was also examined for its effects on breast cancer migration, invasion, and metastasis using transwell and epithelial-to-mesenchymal transition (EMT) assays in vitro and three different mouse (BALB/c and NU/NU nude) models (n = 10 per group). Kaplan-Meier analyses were used to assess survival. All statistical tests were two-sided. RESULTS YR-290 interacted with the kinase domain of TGFβR1, abrogated kinase activity (half maximal inhibitory concentration = 137nM, 95% confidence interval = 126.4 to 147.6nM) and inhibited the TGFβ-mediated downstream signaling pathway and metastasis-associated genes in breast cancer cells. YR-290 inhibited TGFβ-modulated breast cancer cell migration and invasion. In tumor metastasis mouse models, YR-290 almost completely blocked cancer metastasis. Numbers of lung tumor nodules of mice treated with 1mg/kg and 5mg/kg YR-290 were reduced by 74.93% (95% confidence interval = 61.45% to 88.41%) and 94.93% (95% confidence interval = 82.13% to 100%), respectively, compared with control mice. Treatment with YR-290 also statistically significantly prolonged the survival of tumor-bearing mice. CONCLUSIONS YR-290 is a novel inhibitor of tumor metastasis that works by blocking TGFβ signaling pathways.
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Affiliation(s)
- Yuanzhang Fang
- Institute of Biomedical Sciences, East China Normal University, 500 Dongchuan Rd, Shanghai, China
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20
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Bruce DL, Macartney T, Yong W, Shou W, Sapkota GP. Protein phosphatase 5 modulates SMAD3 function in the transforming growth factor-β pathway. Cell Signal 2012; 24:1999-2006. [PMID: 22781750 DOI: 10.1016/j.cellsig.2012.07.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 07/03/2012] [Indexed: 02/02/2023]
Abstract
Protein phosphatases play a key role in balancing the cellular responses to the transforming growth factor-β (TGFβ) signals. Several protein phosphatases have been attributed roles in the regulation of the TGFβ pathway. Among these, PPM1A is the only phosphatase reported to dephosphorylate SMAD2/3 in the nucleus. However we observed PPM1A exclusively in the cytoplasmic fractions independently of TGFβ treatment in all cells tested. These observations imply that a bona fide nuclear SMAD2/3 phosphatase remains elusive. In this study, we report a role for protein phosphatase 5 (PP5) in the TGFβ pathway. We identified PP5 as an interactor of SMAD2/3. Interestingly, in mouse embryonic fibroblast cells derived from PP5-null mice, TGFβ-induced transcriptional responses were significantly enhanced. Rather surprisingly, this enhancement is due to the increased levels of SMAD3 protein observed in PP5-null MEFs compared to the wild type. No differences in the levels of SMAD3 transcripts were observed between the wild-type and PP5-null MEFs. While PP5 is capable of dephosphorylating SMAD3-tail in overexpression assays, we demonstrate that its activity is essential in controlling SMAD3 protein levels in MEFs. We propose that PP5 regulates the TGFβ pathway in MEFs by regulating the expression of SMAD3 protein levels.
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Affiliation(s)
- David L Bruce
- MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee, UK
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21
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Bruce DL, Sapkota GP. Phosphatases in SMAD regulation. FEBS Lett 2012; 586:1897-905. [PMID: 22576046 DOI: 10.1016/j.febslet.2012.02.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 02/02/2012] [Accepted: 02/02/2012] [Indexed: 11/28/2022]
Abstract
SMAD transcription factors are key mediators of the transforming growth factor-beta (TGFß) family of cytokines. Reversible phosphorylation of SMAD proteins plays a key role in regulating their function. Several phosphatases have been proposed to act on SMAD proteins to influence TGFß/BMP signalling. Here we provide an overview of the SMAD regulation by different protein phosphatases and review the evidence supporting each phosphatase as a candidate SMAD-phosphatase.
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Affiliation(s)
- David L Bruce
- MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dow Street, DD1 5EH Dundee, Scotland, UK
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