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Louie JD, Barrios-Camacho CM, Bromberg BH, Hintschich CA, Schwob JE. Spatiotemporal dynamics exhibited by horizontal basal cells reveal a pro-neurogenic pathway during injury-induced olfactory epithelium regeneration. iScience 2024; 27:109600. [PMID: 38650985 PMCID: PMC11033173 DOI: 10.1016/j.isci.2024.109600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 12/21/2023] [Accepted: 03/25/2024] [Indexed: 04/25/2024] Open
Abstract
Horizontal basal cells (HBCs) mediate olfactory epithelium (OE) regeneration following severe tissue injury. The dynamism of the post-injury environment is well illustrated by in silico modeling of RNA sequencing data that demonstrate an evolving HBC transcriptome. Unfortunately, spatiotemporally dynamic processes occurring within HBCs in situ remain poorly understood. Here, we show that HBCs at 24 h post-OE injury spatially redistribute a constellation of proteins, which, in turn, helped to nominate Rac1 as a regulator of HBC differentiation during OE regeneration. Using our primary culture model to activate HBCs pharmacologically, we demonstrate that concurrent Rac1 inhibition attenuates HBC differentiation potential. This in vitro functional impairment manifested in vivo as decreased HBC differentiation into olfactory sensory neurons following HBC-specific Rac1 conditional knockout. Taken together, our data potentiate the design of hyposmia-alleviating therapies and highlight aspects of in situ HBC spatiotemporal dynamics that deserve further investigation.
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Affiliation(s)
- Jonathan D. Louie
- Medical Scientist Training Program, Tufts University School of Medicine, Boston, MA 02111, USA
- Neuroscience Graduate Program, Tufts University Graduate School of Biomedical Sciences, Boston, MA 02111, USA
- Department of Developmental, Molecular & Chemical Biology, Tufts University Graduate School of Biomedical Sciences, Boston, MA 02111, USA
| | - Camila M. Barrios-Camacho
- Neuroscience Graduate Program, Tufts University Graduate School of Biomedical Sciences, Boston, MA 02111, USA
- Department of Developmental, Molecular & Chemical Biology, Tufts University Graduate School of Biomedical Sciences, Boston, MA 02111, USA
| | - Benjamin H. Bromberg
- Department of Developmental, Molecular & Chemical Biology, Tufts University Graduate School of Biomedical Sciences, Boston, MA 02111, USA
| | - Constantin A. Hintschich
- Department of Developmental, Molecular & Chemical Biology, Tufts University Graduate School of Biomedical Sciences, Boston, MA 02111, USA
- Department of Otorhinolaryngology, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114, USA
| | - James E. Schwob
- Department of Developmental, Molecular & Chemical Biology, Tufts University Graduate School of Biomedical Sciences, Boston, MA 02111, USA
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2
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Su Y, Long Y, Xie K. Cingulin family: Structure, function and clinical significance. Life Sci 2024; 341:122504. [PMID: 38354973 DOI: 10.1016/j.lfs.2024.122504] [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: 11/09/2023] [Revised: 01/21/2024] [Accepted: 02/11/2024] [Indexed: 02/16/2024]
Abstract
Cingulin and its paralog paracingulin are vital components of the apical junctional complex in vertebrate epithelial and endothelial cells. They are both found in tight junctions (TJ), and paracingulin is also detectable in adherens junctions (AJ) as TJ cytoplasmic plaque proteins. Cingulin and paracingulin interact with other proteins to perform functions. They interact with cytoskeletal proteins, modulate the activity of small GTPases, such as RhoA and Rac1, and regulate gene expression. In addition, cingulin and paracingulin regulate barrier function and many pathological processes, including inflammation and tumorigenesis. In this review, we summarize the discovery and structure, expression and subcellular distribution, and molecular interactions of cingulin family proteins and discuss their role in development, physiology, and pathological processes.
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Affiliation(s)
- Yuling Su
- Center for Pancreatic Cancer Research, The South China University of Technology School of Medicine, Guangzhou, Guangdong 510006, China
| | - You Long
- Center for Pancreatic Cancer Research, The South China University of Technology School of Medicine, Guangzhou, Guangdong 510006, China
| | - Keping Xie
- Center for Pancreatic Cancer Research, The South China University of Technology School of Medicine, Guangzhou, Guangdong 510006, China; The Second Affiliated Hospital and Guangzhou First People's Hospital, South China University of Technology School of Medicine, Guangdong 510006, China; The South China University of Technology Comprehensive Cancer Center, Guangzhou, Guangdong 510006, China.
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3
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Wang L, Tang L, Zhou L, Lai Y, Li H, Wang X, Liu X. Identification of CGNL1 as a diagnostic marker in fibroblasts of diabetic foot ulcers: Insights from single cell RNA sequencing and bulk sequencing data. Int J Immunopathol Pharmacol 2024; 38:3946320241265945. [PMID: 39102374 DOI: 10.1177/03946320241265945] [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] [Indexed: 08/07/2024] Open
Abstract
OBJECTIVES This study aimed to explore the unique transcriptional feature of fibroblasts subtypes and the role of ferroptosis in diabetic foot ulcers (DFUs). METHODS The GEO (Gene Expression Omnibus) was searched to obtain the DFUs single-cell and transcriptional datasets. After identifying cell types by classic marker genes, the integrated single-cell dataset was used to run trajectory inference, RNA velocity, and ligand-receptor interaction analysis. Next, bulk RNA-seq datasets of DFUs were analyzed to the key ferroptosis genes. RESULTS Here, we profile 83529 single transcriptomes from the foot samples utilizing single-cell sequencing (scRNA-seq) data of DFU from GEO database and identified 12 cell types, with fibroblasts exhibiting elevated levels of ferroptosis activity and substantial cellular heterogeneity. Our results defined six main fibroblast subsets that showed mesenchymal, secretory-reticular, secretory-papillary, pro-inflammatory, myogenesis, and healing-enriched functional annotations. Trajectory inference and cell-cell communication analysis revealed two major cell fates with subpopulations of fibroblasts and altered ligand-receptor interactions. Bulk RNA sequencing data identified CGNL1 as a distinctive diagnostic signature in fibroblasts. Notably, CGNL1 positively correlated with pro-inflammatory fibroblasts. CONCLUSIONS Overall, our analysis delineated the heterogeneity present in cell populations of DFUs, showing distinct fibroblast subtypes characterized by their own unique transcriptional features and enrichment functions. Our study will help us better understand DFUs pathogenesis and identifies CGNL1 as a potential target for DFUs therapies.
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Affiliation(s)
- Li Wang
- Research Centre of Basic Intergrative Medicine, School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Lulu Tang
- The First College of Clinical Medicine, Guangzhou University of Chinese Medicine, Guangzhou, China
- First Affiliated Hospital of Guangzhou University of Chinese Medicine, Ghangzhou, China
| | - Lingna Zhou
- First Affiliated Hospital of Guangzhou University of Chinese Medicine, Ghangzhou, China
| | - Yingtao Lai
- First Affiliated Hospital of Guangzhou University of Chinese Medicine, Ghangzhou, China
| | - Hui Li
- Research Centre of Basic Intergrative Medicine, School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Xiaojun Wang
- First Affiliated Hospital of Guangzhou University of Chinese Medicine, Ghangzhou, China
| | - Xiaoyi Liu
- Research Centre of Basic Intergrative Medicine, School of Basic Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China
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4
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Hino N, Matsuda K, Jikko Y, Maryu G, Sakai K, Imamura R, Tsukiji S, Aoki K, Terai K, Hirashima T, Trepat X, Matsuda M. A feedback loop between lamellipodial extension and HGF-ERK signaling specifies leader cells during collective cell migration. Dev Cell 2022; 57:2290-2304.e7. [PMID: 36174555 DOI: 10.1016/j.devcel.2022.09.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 07/11/2022] [Accepted: 09/07/2022] [Indexed: 11/03/2022]
Abstract
Upon the initiation of collective cell migration, the cells at the free edge are specified as leader cells; however, the mechanism underlying the leader cell specification remains elusive. Here, we show that lamellipodial extension after the release from mechanical confinement causes sustained extracellular signal-regulated kinase (ERK) activation and underlies the leader cell specification. Live-imaging of Madin-Darby canine kidney (MDCK) cells and mouse epidermis through the use of Förster resonance energy transfer (FRET)-based biosensors showed that leader cells exhibit sustained ERK activation in a hepatocyte growth factor (HGF)-dependent manner. Meanwhile, follower cells exhibit oscillatory ERK activation waves in an epidermal growth factor (EGF) signaling-dependent manner. Lamellipodial extension at the free edge increases the cellular sensitivity to HGF. The HGF-dependent ERK activation, in turn, promotes lamellipodial extension, thereby forming a positive feedback loop between cell extension and ERK activation and specifying the cells at the free edge as the leader cells. Our findings show that the integration of physical and biochemical cues underlies the leader cell specification during collective cell migration.
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Affiliation(s)
- Naoya Hino
- Research Center for Dynamic Living Systems, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan; Institute of Science and Technology Austria, 3400 Klosterneuburg, Austria.
| | - Kimiya Matsuda
- Research Center for Dynamic Living Systems, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yuya Jikko
- Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Gembu Maryu
- Division of Quantitative Biology, National Institute for Basic Biology, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan
| | - Katsuya Sakai
- Division of Tumor Dynamics and Regulation, Cancer Research Institute, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan; WPI-Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma, Kanazawa 920-1192, Japan
| | - Ryu Imamura
- Division of Tumor Dynamics and Regulation, Cancer Research Institute, Kanazawa University, Kakuma, Kanazawa 920-1192, Japan; WPI-Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Kakuma, Kanazawa 920-1192, Japan
| | - Shinya Tsukiji
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan; Department of Nanopharmaceutical Sciences, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
| | - Kazuhiro Aoki
- Division of Quantitative Biology, National Institute for Basic Biology, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan; Quantitative Biology Research Group, Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan; Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan
| | - Kenta Terai
- Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Tsuyoshi Hirashima
- Research Center for Dynamic Living Systems, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan; Hakubi Center, Kyoto University, Kyoto, Japan; Japan Science and Technology Agency, Presto, Kawaguchi, Japan
| | - Xavier Trepat
- Institute for Bioengineering of Catalonia, Barcelona 08028, Spain; Faculty of Medicine, University of Barcelona, Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain; Center for Networked Biomedical Research on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Barcelona, Spain
| | - Michiyuki Matsuda
- Research Center for Dynamic Living Systems, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan; Department of Pathology and Biology of Diseases, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan; Institute for Integrated Cell-Material Sciences, Kyoto University Sakyo-ku, Kyoto 606-8501, Japan.
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5
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Ebnet K, Gerke V. Rho and Rab Family Small GTPases in the Regulation of Membrane Polarity in Epithelial Cells. Front Cell Dev Biol 2022; 10:948013. [PMID: 35859901 PMCID: PMC9289151 DOI: 10.3389/fcell.2022.948013] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 06/14/2022] [Indexed: 11/27/2022] Open
Abstract
Membrane polarity, defined as the asymmetric distribution of lipids and proteins in the plasma membrane, is a critical prerequisite for the development of multicellular tissues, such as epithelia and endothelia. Membrane polarity is regulated by polarized trafficking of membrane components to specific membrane domains and requires the presence of intramembrane diffusion barriers that prevent the intermixing of asymmetrically distributed membrane components. This intramembrane diffusion barrier is localized at the tight junctions (TJs) in these cells. Both the formation of cell-cell junctions and the polarized traffic of membrane proteins and lipids are regulated by Rho and Rab family small GTPases. In this review article, we will summarize the recent developments in the regulation of apico-basal membrane polarity by polarized membrane traffic and the formation of the intramembrane diffusion barrier in epithelial cells with a particular focus on the role of Rho and Rab family small GTPases.
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Affiliation(s)
- Klaus Ebnet
- Institute-Associated Research Group: Cell Adhesion and Cell Polarity, Institute of Medical Biochemistry, ZMBE, University of Münster, Münster, Germany
- Interdisciplinary Clinical Research Center (IZKF), University of Münster, Münster, Germany
- Cells-In-Motion Cluster of Excellence (EXC1003-CiM), University of Münster, Münster, Germany
- *Correspondence: Klaus Ebnet, ; Volker Gerke,
| | - Volker Gerke
- Institute-Associated Research Group: Cell Adhesion and Cell Polarity, Institute of Medical Biochemistry, ZMBE, University of Münster, Münster, Germany
- Interdisciplinary Clinical Research Center (IZKF), University of Münster, Münster, Germany
- Cells-In-Motion Cluster of Excellence (EXC1003-CiM), University of Münster, Münster, Germany
- *Correspondence: Klaus Ebnet, ; Volker Gerke,
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The ACE2 Receptor for Coronavirus Entry Is Localized at Apical Cell—Cell Junctions of Epithelial Cells. Cells 2022; 11:cells11040627. [PMID: 35203278 PMCID: PMC8870730 DOI: 10.3390/cells11040627] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/03/2022] [Accepted: 02/09/2022] [Indexed: 02/04/2023] Open
Abstract
Transmembrane proteins of adherens and tight junctions are known targets for viruses and bacterial toxins. The coronavirus receptor ACE2 has been localized at the apical surface of epithelial cells, but it is not clear whether ACE2 is localized at apical Cell—Cell junctions and whether it associates with junctional proteins. Here we explored the expression and localization of ACE2 and its association with transmembrane and tight junction proteins in epithelial tissues and cultured cells by data mining, immunoblotting, immunofluorescence microscopy, and co-immunoprecipitation experiments. ACE2 mRNA is abundant in epithelial tissues, where its expression correlates with the expression of the tight junction proteins cingulin and occludin. In cultured epithelial cells ACE2 mRNA is upregulated upon differentiation and ACE2 protein is widely expressed and co-immunoprecipitates with the transmembrane proteins ADAM17 and CD9. We show by immunofluorescence microscopy that ACE2 colocalizes with ADAM17 and CD9 and the tight junction protein cingulin at apical junctions of intestinal (Caco-2), mammary (Eph4) and kidney (mCCD) epithelial cells. These observations identify ACE2, ADAM17 and CD9 as new epithelial junctional transmembrane proteins and suggest that the cytokine-enhanced endocytic internalization of junction-associated protein complexes comprising ACE2 may promote coronavirus entry.
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7
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Díaz-Díaz C, Baonza G, Martín-Belmonte F. The vertebrate epithelial apical junctional complex: Dynamic interplay between Rho GTPase activity and cell polarization processes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183398. [DOI: 10.1016/j.bbamem.2020.183398] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 06/05/2020] [Accepted: 06/11/2020] [Indexed: 12/31/2022]
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8
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Rouaud F, Sluysmans S, Flinois A, Shah J, Vasileva E, Citi S. Scaffolding proteins of vertebrate apical junctions: structure, functions and biophysics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183399. [DOI: 10.1016/j.bbamem.2020.183399] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 06/05/2020] [Accepted: 06/11/2020] [Indexed: 12/11/2022]
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9
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Schwayer C, Shamipour S, Pranjic-Ferscha K, Schauer A, Balda M, Tada M, Matter K, Heisenberg CP. Mechanosensation of Tight Junctions Depends on ZO-1 Phase Separation and Flow. Cell 2020; 179:937-952.e18. [PMID: 31675500 DOI: 10.1016/j.cell.2019.10.006] [Citation(s) in RCA: 131] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 08/19/2019] [Accepted: 10/07/2019] [Indexed: 10/25/2022]
Abstract
Cell-cell junctions respond to mechanical forces by changing their organization and function. To gain insight into the mechanochemical basis underlying junction mechanosensitivity, we analyzed tight junction (TJ) formation between the enveloping cell layer (EVL) and the yolk syncytial layer (YSL) in the gastrulating zebrafish embryo. We found that the accumulation of Zonula Occludens-1 (ZO-1) at TJs closely scales with tension of the adjacent actomyosin network, revealing that these junctions are mechanosensitive. Actomyosin tension triggers ZO-1 junctional accumulation by driving retrograde actomyosin flow within the YSL, which transports non-junctional ZO-1 clusters toward the TJ. Non-junctional ZO-1 clusters form by phase separation, and direct actin binding of ZO-1 is required for stable incorporation of retrogradely flowing ZO-1 clusters into TJs. If the formation and/or junctional incorporation of ZO-1 clusters is impaired, then TJs lose their mechanosensitivity, and consequently, EVL-YSL movement is delayed. Thus, phase separation and flow of non-junctional ZO-1 confer mechanosensitivity to TJs.
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Affiliation(s)
- Cornelia Schwayer
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Shayan Shamipour
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | | | - Alexandra Schauer
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Maria Balda
- Institute of Ophthalmology, University College London, London, UK
| | - Masazumi Tada
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Karl Matter
- Institute of Ophthalmology, University College London, London, UK
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10
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Ma J, Liu X, Liu P, Lu W, Shen X, Ma R, Zong H. Identification of a new p53 responsive element in the promoter region of anillin. Int J Mol Med 2020; 45:1563-1570. [PMID: 32323752 DOI: 10.3892/ijmm.2020.4527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 12/06/2019] [Indexed: 11/06/2022] Open
Abstract
The expression of anillin mRNA and protein is regulated in a cell cycle‑dependent manner. However, the mechanism underlying this process is unclear. Previous studies analyzing the sequence of the 5'‑untranslated region of anillin have unveiled several putative p53 binding sites. Therefore, the present study hypothesized that the anillin gene may be repressed by p53 and that the commonly observed mutation (or loss of function) of p53 may serve a role in this phenotype. Bioinformatic analysis of the anillin promoter region revealed potential p53 responsive elements. Of those identified, 2 were able to bind p53 protein, as determined via a chromatin immunoprecipitation assay. Although it was hypothesized that DNA damage and resultant p53 expression would repress anillin expression, the results revealed that anillin mRNA and protein expression levels were negatively regulated by DNA damage in the wild‑type p53 cells, but not in the isogenic p53 null cells. Furthermore, DNA sequences encompassing the p53 binding site downregulated luciferase transgenes in a p53 dependent manner. Taken together, these data indicated that anillin was negatively regulated by p53 and that anillin overexpression observed in cancer may be a p53‑mediated phenomenon. The data from the present study provided further evidence for the role of p53 in the biologically crucial process of cytokinesis.
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Affiliation(s)
- Jiao Ma
- Department of Biochemistry and Molecular Cell Biology, Shanghai Jiaotong University Medical School, Shanghai 200025, P.R. China
| | - Xinying Liu
- Department of Biochemistry and Molecular Cell Biology, Shanghai Jiaotong University Medical School, Shanghai 200025, P.R. China
| | - Pengyi Liu
- Department of Biochemistry and Molecular Cell Biology, Shanghai Jiaotong University Medical School, Shanghai 200025, P.R. China
| | - Wenqing Lu
- Department of Biochemistry and Molecular Cell Biology, Shanghai Jiaotong University Medical School, Shanghai 200025, P.R. China
| | - Xinxin Shen
- Department of Biochemistry and Molecular Cell Biology, Shanghai Jiaotong University Medical School, Shanghai 200025, P.R. China
| | - Ruixiang Ma
- Department of Biochemistry and Molecular Cell Biology, Shanghai Jiaotong University Medical School, Shanghai 200025, P.R. China
| | - Hongliang Zong
- Shanghai PerHum Therapeutics Co. Ltd., Shanghai 200052, P.R. China
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11
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Díaz-Coránguez M, Liu X, Antonetti DA. Tight Junctions in Cell Proliferation. Int J Mol Sci 2019; 20:E5972. [PMID: 31783547 PMCID: PMC6928848 DOI: 10.3390/ijms20235972] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 11/22/2019] [Accepted: 11/22/2019] [Indexed: 12/23/2022] Open
Abstract
Tight junction (TJ) proteins form a continuous intercellular network creating a barrier with selective regulation of water, ion, and solutes across endothelial, epithelial, and glial tissues. TJ proteins include the claudin family that confers barrier properties, members of the MARVEL family that contribute to barrier regulation, and JAM molecules, which regulate junction organization and diapedesis. In addition, the membrane-associated proteins such as MAGUK family members, i.e., zonula occludens, form the scaffold linking the transmembrane proteins to both cell signaling molecules and the cytoskeleton. Most studies of TJ have focused on the contribution to cell-cell adhesion and tissue barrier properties. However, recent studies reveal that, similar to adherens junction proteins, TJ proteins contribute to the control of cell proliferation. In this review, we will summarize and discuss the specific role of TJ proteins in the control of epithelial and endothelial cell proliferation. In some cases, the TJ proteins act as a reservoir of critical cell cycle modulators, by binding and regulating their nuclear access, while in other cases, junctional proteins are located at cellular organelles, regulating transcription and proliferation. Collectively, these studies reveal that TJ proteins contribute to the control of cell proliferation and differentiation required for forming and maintaining a tissue barrier.
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Affiliation(s)
| | | | - David A. Antonetti
- Department of Ophthalmology and Visual Sciences, University of Michigan, Kellogg Eye Center, Ann Arbor, MI 48105, USA; (M.D.-C.); (X.L.)
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12
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Abstract
Tight junctions (TJ) play a central role in the homeostasis of epithelial and endothelial tissues, by providing a semipermeable barrier to ions and solutes, by contributing to the maintenance of cell polarity, and by functioning as signaling platforms. TJ are associated with the actomyosin and microtubule cytoskeletons, and the crosstalk with the cytoskeleton is fundamental for junction biogenesis and physiology. TJ are spatially and functionally connected to adherens junctions (AJ), which are essential for the maintenance of tissue integrity. Mechano-sensing and mechano-transduction properties of several AJ proteins have been characterized during the last decade. However, little is known about how mechanical forces act on TJ and their proteins, how TJ control the mechanical properties of cells and tissues, and what are the underlying molecular mechanisms. Here I review recent studies that have advanced our understanding of the relationships between mechanical force and TJ biology.
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13
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Rouaud F, Vasileva E, Spadaro D, Tsukita S, Citi S. R40.76 binds to the α domain of ZO-1: role of ZO-1 (α+) in epithelial differentiation and mechano-sensing. Tissue Barriers 2019; 7:e1653748. [PMID: 31438766 PMCID: PMC6748370 DOI: 10.1080/21688370.2019.1653748] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The barrier function of epithelia and endothelia depends on tight junctions, which are formed by the polymerization of claudins on a scaffold of ZO proteins. Two differentially spliced isoforms of ZO-1 have been described, depending on the presence of the α domain, but the function of this domain is unclear. ZO-1 also contains a C-terminal ZU5 domain, which is involved in a mechano-sensitive intramolecular interaction with the central (ZPSG) region of ZO-1. Here we use immunoblotting and immunofluorescence to map the binding sites for commercially available monoclonal and polyclonal antibodies against ZO-1, and for a new polyclonal antibody (R3) that we developed against the ZO-1 C-terminus. We demonstrate that antibody R40.76 binds to the α domain, and the R3 antibody binds to the ZU5 domain. The (α+) isoform of ZO-1 shows higher expression in epithelial versus endothelial cells, and in differentiated versus undifferentiated primary keratinocytes, suggesting a link to epithelial differentiation and a potential molecular adaptation to junctions subjected to stronger mechanical forces. These results provide new tools and hypotheses to investigate the role of the α and ZU5 domains in ZO-1 mechano-sensing and dynamic interactions with the cytoskeleton and junctional ligands.
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Affiliation(s)
- Florian Rouaud
- Department of Cell Biology, Faculty of Sciences, University of Geneva , Geneva , Switzerland.,Institute of Genetics and Genomics of Geneva, University of Geneva , Geneva , Switzerland
| | - Ekaterina Vasileva
- Department of Cell Biology, Faculty of Sciences, University of Geneva , Geneva , Switzerland.,Institute of Genetics and Genomics of Geneva, University of Geneva , Geneva , Switzerland
| | - Domenica Spadaro
- Department of Cell Biology, Faculty of Sciences, University of Geneva , Geneva , Switzerland.,Institute of Genetics and Genomics of Geneva, University of Geneva , Geneva , Switzerland
| | - Sachiko Tsukita
- Strategic Innovation and Research Center, Teikyo University , Tokyo , Japan.,Graduate School of Frontier Biosciences, Osaka University , Osaka , Japan
| | - Sandra Citi
- Department of Cell Biology, Faculty of Sciences, University of Geneva , Geneva , Switzerland.,Institute of Genetics and Genomics of Geneva, University of Geneva , Geneva , Switzerland
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14
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Chung VY, Tan TZ, Ye J, Huang RL, Lai HC, Kappei D, Wollmann H, Guccione E, Huang RYJ. The role of GRHL2 and epigenetic remodeling in epithelial-mesenchymal plasticity in ovarian cancer cells. Commun Biol 2019; 2:272. [PMID: 31372511 PMCID: PMC6656769 DOI: 10.1038/s42003-019-0506-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 06/18/2019] [Indexed: 12/12/2022] Open
Abstract
Cancer cells exhibit phenotypic plasticity during epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET) involving intermediate states. To study genome-wide epigenetic remodeling associated with EMT plasticity, we integrate the analyses of DNA methylation, ChIP-sequencing of five histone marks (H3K4me1, H3K4me3, H3K27Ac, H3K27me3 and H3K9me3) and transcriptome profiling performed on ovarian cancer cells with different epithelial/mesenchymal states and on a knockdown model of EMT suppressor Grainyhead-like 2 (GRHL2). We have identified differentially methylated CpG sites associated with EMT, found at promoters of epithelial genes and GRHL2 binding sites. GRHL2 knockdown results in CpG methylation gain and nucleosomal remodeling (reduction in permissive marks H3K4me3 and H3K27ac; elevated repressive mark H3K27me3), resembling the changes observed across progressive EMT states. Epigenetic-modifying agents such as 5-azacitidine, GSK126 and mocetinostat further reveal cell state-dependent plasticity upon GRHL2 overexpression. Overall, we demonstrate that epithelial genes are subject to epigenetic control during intermediate phases of EMT/MET involving GRHL2.
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Affiliation(s)
- Vin Yee Chung
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599 Singapore
| | - Tuan Zea Tan
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599 Singapore
| | - Jieru Ye
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599 Singapore
| | - Rui-Lan Huang
- Department of Obstetrics and Gynecology, Shuang Ho Hospital, Taipei Medical University, 11031 Taipei, Taiwan
| | - Hung-Cheng Lai
- Department of Obstetrics and Gynecology, Shuang Ho Hospital, Taipei Medical University, 11031 Taipei, Taiwan
| | - Dennis Kappei
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599 Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117596 Singapore
| | - Heike Wollmann
- Institute of Molecular and Cell Biology, A*STAR, Singapore, 138673 Singapore
| | - Ernesto Guccione
- Institute of Molecular and Cell Biology, A*STAR, Singapore, 138673 Singapore
| | - Ruby Yun-Ju Huang
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, 117599 Singapore
- School of Medicine, College of Medicine, National Taiwan University, 10051 Taipei, Taiwan
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15
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Abstract
The cytoskeleton is crucially important for the assembly of cell-cell junctions and the homeostatic regulation of their functions. Junctional proteins act, in turn, as anchors for cytoskeletal filaments, and as regulators of cytoskeletal dynamics and signalling proteins. The cross-talk between junctions and the cytoskeleton is critical for the morphogenesis and physiology of epithelial and other tissues, but is not completely understood. Microtubules are implicated in the delivery of junctional proteins to cell-cell contact sites, in the differentiation and spatial organization of the cytoplasm, and in the stabilization of the barrier and adhesive functions of junctions. Here we focus on the relationships between microtubules and junctions of vertebrate epithelial cells. We highlight recent discoveries on the molecular underpinnings of microtubule-junction interactions, and report new data about the interaction of cingulin and paracingulin with microtubules. We also propose a possible new role of junctions as “molecular sinks” for microtubule-associated signalling proteins.
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Affiliation(s)
- Ekaterina Vasileva
- a Department of Cell Biology, Faculty of Sciences and Institute for Genetics and Genomics in Geneva (iGE3) , University of Geneva , Geneva , Switzerland
| | - Sandra Citi
- a Department of Cell Biology, Faculty of Sciences and Institute for Genetics and Genomics in Geneva (iGE3) , University of Geneva , Geneva , Switzerland
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16
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Yano T, Torisawa T, Oiwa K, Tsukita S. AMPK-dependent phosphorylation of cingulin reversibly regulates its binding to actin filaments and microtubules. Sci Rep 2018; 8:15550. [PMID: 30341325 PMCID: PMC6195624 DOI: 10.1038/s41598-018-33418-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 09/26/2018] [Indexed: 12/20/2022] Open
Abstract
Cytoskeletal organization is essential for the precise morphogenesis of cells, tissues, and organs. Cytoskeletons, bound to scaffolding proteins, regulate the apical junction complex (AJC), which is composed of tight and adherens junctions, and located at the apical side of epithelial cell sheets. Cingulin is a tight junction-associated protein that binds to both actin filaments and microtubules. However, how cingulin binds to microtubules and whether cingulin can bind to actin and microtubules simultaneously are unclear. Here we examined the mechanisms behind cingulin’s cytoskeleton-binding properties. First, using total internal reflection fluorescence microscopy, we detected cingulin at microtubule cross points. We then found the interdomain interactions in cingulin molecules. Notably, we found that this interaction was regulated by AMPK-dependent phosphorylation and changed cingulin’s conformation and binding properties to actin filaments and microtubules. Finally, we found that the AMPK-regulated cingulin properties regulated the barrier functions of epithelial cell sheets. We propose that the cellular metabolic state, which involves AMPK, can contribute to the organization and maintenance of epithelial tissues through cingulin’s tight junction/cytoskeleton regulation.
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Affiliation(s)
- Tomoki Yano
- Laboratory of Biological Science, Graduate School of Frontier Biosciences and Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan.
| | - Takayuki Torisawa
- National Institute of Information and Communications Technology, Advanced ICT Research Institute, Kobe, Hyogo, 651-2492, Japan.,Department of Genetics, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Mishima, 411-8540, Japan
| | - Kazuhiro Oiwa
- National Institute of Information and Communications Technology, Advanced ICT Research Institute, Kobe, Hyogo, 651-2492, Japan
| | - Sachiko Tsukita
- Laboratory of Biological Science, Graduate School of Frontier Biosciences and Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan.
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17
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Braga V. Signaling by Small GTPases at Cell-Cell Junctions: Protein Interactions Building Control and Networks. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a028746. [PMID: 28893858 DOI: 10.1101/cshperspect.a028746] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
A number of interesting reports highlight the intricate network of signaling proteins that coordinate formation and maintenance of cell-cell contacts. We have much yet to learn about how the in vitro binding data is translated into protein association inside the cells and whether such interaction modulates the signaling properties of the protein. What emerges from recent studies is the importance to carefully consider small GTPase activation in the context of where its activation occurs, which upstream regulators are involved in the activation/inactivation cycle and the GTPase interacting partners that determine the intracellular niche and extent of signaling. Data discussed here unravel unparalleled cooperation and coordination of functions among GTPases and their regulators in supporting strong adhesion between cells.
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Affiliation(s)
- Vania Braga
- Molecular Medicine, National Heart and Lung Institute, Faculty of Medicine, Imperial College London, London SW7 2AZ, United Kingdom
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18
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Chrifi I, Hermkens D, Brandt MM, van Dijk CGM, Bürgisser PE, Haasdijk R, Pei J, van de Kamp EHM, Zhu C, Blonden L, Kros JM, Duncker DJ, Duckers HJ, Cheng C. Cgnl1, an endothelial junction complex protein, regulates GTPase mediated angiogenesis. Cardiovasc Res 2018; 113:1776-1788. [PMID: 29016873 PMCID: PMC5852532 DOI: 10.1093/cvr/cvx175] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 08/29/2017] [Indexed: 12/23/2022] Open
Abstract
Aims The formation of cell–cell and cell–extra cellular matrix (ECM) contacts by endothelial cells (ECs) is crucial for the stability and integrity of a vascular network. We previously identified cingulin-like 1 (Cgnl1) in a transcriptomic screen for new angiogenic modulators. Here we aim to study the function of the cell–cell junction associated protein Cgnl1 during vessel formation. Methods and results Unlike family member cingulin, Cgnl1 expression is enriched in ECs during vascular growth. Cgnl1 is important for the formation of multicellular tubule structures, as shown in vitro using loss-of function assays in a 3D matrix co-culture system that uses primary human ECs and supporting mural cells. Further studies revealed that Cgnl1 regulates vascular growth by promoting Ve-cadherin association with the actin cytoskeleton, thereby stabilizing adherens junctions. Cgnl1 also regulates focal adhesion assembly in response to ECM contact, promoting vinculin and paxillin recruitment and focal adhesion kinase signalling. In vivo, we demonstrate in a postnatal retinal vascular development model in mice that Cgnl1 function is crucial for sustaining neovascular growth and stability. Conclusions Our data demonstrate a functional relevance for Cgnl1 as a defining factor in new vessel formation both in vitro and in vivo.
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Affiliation(s)
- Ihsan Chrifi
- Department of Cardiology, Thoraxcenter, Erasmus University Medical Center, Rotterdam, PO Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Dorien Hermkens
- Department of Cardiology, Thoraxcenter, Erasmus University Medical Center, Rotterdam, PO Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Maarten M Brandt
- Department of Cardiology, Thoraxcenter, Erasmus University Medical Center, Rotterdam, PO Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Christian G M van Dijk
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Petra E Bürgisser
- Department of Cardiology, Thoraxcenter, Erasmus University Medical Center, Rotterdam, PO Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Remco Haasdijk
- Department of Cardiology, Thoraxcenter, Erasmus University Medical Center, Rotterdam, PO Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Jiayi Pei
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Esther H M van de Kamp
- Department of Cardiology, Thoraxcenter, Erasmus University Medical Center, Rotterdam, PO Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Changbin Zhu
- Department of Pathology, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Lau Blonden
- Department of Cardiology, Thoraxcenter, Erasmus University Medical Center, Rotterdam, PO Box 2040, 3000 CA Rotterdam, The Netherlands
| | - Johan M Kros
- Department of Pathology, Erasmus University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Dirk J Duncker
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Henricus J Duckers
- Department of Interventional Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Caroline Cheng
- Department of Cardiology, Thoraxcenter, Erasmus University Medical Center, Rotterdam, PO Box 2040, 3000 CA Rotterdam, The Netherlands.,Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
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19
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Zhang L, Feng T, Spicer LJ. The role of tight junction proteins in ovarian follicular development and ovarian cancer. Reproduction 2018; 155:R183-R198. [PMID: 29374086 DOI: 10.1530/rep-17-0503] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 01/26/2018] [Indexed: 01/01/2023]
Abstract
Tight junctions (TJ) are protein structures that control the transport of water, ions and macromolecules across cell layers. Functions of the transmembrane TJ protein, occluding (OCLN) and the cytoplasmic TJ proteins, tight junction protein 1 (TJP1; also known as zona occludens protein-1), cingulin (CGN) and claudins (CLDN) are reviewed, and current evidence of their role in the ovarian function is reviewed. Abundance of OCLN, CLDNs and TJP1 mRNA changed during follicular growth. In vitro treatment with various growth factors known to affect ovarian folliculogenesis indicated that CGN, OCLN and TJP1 are hormonally regulated. The summarized studies indicate that expression of TJ proteins (i.e., OCLN, CLDN, TJP1 and CGN) changes with follicle size in a variety of vertebrate species but whether these changes in TJ proteins are increased or decreased depends on species and cell type. Evidence indicates that autocrine, paracrine and endocrine regulators, such as fibroblast growth factor-9, epidermal growth factor, androgens, tumor necrosis factor-α and glucocorticoids may modulate these TJ proteins. Additional evidence presented indicates that TJ proteins may be involved in ovarian cancer development in addition to normal follicular and luteal development. A model is proposed suggesting that hormonal downregulation of TJ proteins during ovarian follicular development could reduce barrier function (i.e., selective permeability of molecules between theca and granulosa cells) and allow for an increase in the volume of follicular fluid as well as allow additional serum factors into the follicle that may directly impact granulosa cell functions.
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Affiliation(s)
- Lingna Zhang
- Department of Animal ScienceOklahoma State University, Stillwater, Oklahoma, USA
| | - Tao Feng
- Institute of Animal Husbandry and Veterinary MedicineBeijing Academy of Agriculture and Forestry Sciences, Beijing, China
| | - Leon J Spicer
- Department of Animal ScienceOklahoma State University, Stillwater, Oklahoma, USA
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20
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Xu S, Zhang Y, Wang J, Li K, Tan K, Liang K, Shen J, Cai D, Jin D, Li M, Xiao G, Xu J, Jiang Y, Bai X. TSC1 regulates osteoclast podosome organization and bone resorption through mTORC1 and Rac1/Cdc42. Cell Death Differ 2018; 25:1549-1566. [PMID: 29358671 DOI: 10.1038/s41418-017-0049-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 11/13/2017] [Accepted: 11/27/2017] [Indexed: 01/08/2023] Open
Abstract
Reorganization of the podosome into the sealing zone is crucial for osteoclasts (OCLs) to resorb bone, but the underlying mechanisms are unclear. Here, we show that tuberous sclerosis complex 1 (TSC1) functions centrally in OCLs to promote podosome organization and bone resorption through mechanistic target of rapamycin complex 1 (mTORC1) and the small GTPases Rac1/Cdc42. During osteoclastogenesis, enhanced expression of TSC1 downregulates mTORC1 activity. TSC1 deletion in OCLs reduced podosome belt formation in vitro and sealing zone formation in vivo, leading to bone resorption deficiency and osteopetrosis. Mechanistically, TSC1 promoted podosome superstructure assembly by releasing mTORC1-dependent negative feedback inhibition of Rac1/Cdc42. Rapamycin and active Rac1/Cdc42 restore podosome organization and bone resorption and alleviate osteopetrotic phenotypes in mutant mice. Our findings reveal an essential role of TSC1 signaling in the regulation of bone resorption. Targeting TSC1 represents a novel strategy to inhibit bone resorption and prevent bone loss-related diseases.
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Affiliation(s)
- Song Xu
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China.,Department of Arthroplasty, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Yue Zhang
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China.,Academy of Orthopedics, Guangdong Province, The Third Affiliated Hospital of Southern Medical University, Guangzhou, 510630, China
| | - Jian Wang
- Department of Arthroplasty, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Kai Li
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China.,Academy of Orthopedics, Guangdong Province, The Third Affiliated Hospital of Southern Medical University, Guangzhou, 510630, China
| | - Kang Tan
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Kangyan Liang
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Junhui Shen
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Daozhang Cai
- Academy of Orthopedics, Guangdong Province, The Third Affiliated Hospital of Southern Medical University, Guangzhou, 510630, China
| | - Dadi Jin
- Academy of Orthopedics, Guangdong Province, The Third Affiliated Hospital of Southern Medical University, Guangzhou, 510630, China
| | - Mangmang Li
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Guozhi Xiao
- Department of Biochemistry and Department of Biology and Shenzhen Key Laboratory of Cell Microenvironment, South University of Science and Technology of China, Shenzhen, 518055, China
| | - Jiake Xu
- Molecular Laboratory, School of Pathology and Laboratory Medicine, The University of Western Australia, M504, Perth, 6009, Australia
| | - Yu Jiang
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, 15260, USA
| | - Xiaochun Bai
- Department of Cell Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China. .,Department of Arthroplasty, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China.
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21
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Derksen PWB, van de Ven RAH. Shared mechanisms regulate spatiotemporal RhoA-dependent actomyosin contractility during adhesion and cell division. Small GTPases 2018; 11:113-121. [PMID: 29291271 DOI: 10.1080/21541248.2017.1366966] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Local modulation of the actin cytoskeleton is essential for the initiation and maintenance of strong homotypic adhesive interfaces between neighboring cells. The epithelial adherens junction (AJ) fulfils a central role in this process by mediating E-cadherin interactions and functioning as a signaling scaffold to control the activity of the small GTPase RhoA and subsequent actomyosin contractility. Interestingly, a number of regulatory proteins that modulate RhoA activity at the AJ also control RhoA during cytokinesis, an actomyosin-dependent process that divides the cytoplasm to generate two daughter cells at the final stages of mitosis. Recent insights have revealed that the central player in AJ stability, p120-catenin (p120), interacts with and modulates essential regulators of actomyosin contraction during cytokinesis. In cancer, loss of this modulation is a common event during tumor progression that can induce chromosomal instability and tumor progression.In this review, we will highlight the functional differences and similarities of the different RhoA-associated factors that have been linked to both the regulation of cell-cell adhesion and cytokinesis.
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Affiliation(s)
- Patrick W B Derksen
- Department of Pathology, University Medical Center Utrecht, Heidelberglaan CX Utrecht, the Netherlands
| | - Robert A H van de Ven
- Department of Cell Biology, Harvard Medical School, 240 Longwood Avenue Boston, MA, USA
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22
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Von Stetina SE, Liang J, Marnellos G, Mango SE. Temporal regulation of epithelium formation mediated by FoxA, MKLP1, MgcRacGAP, and PAR-6. Mol Biol Cell 2017; 28:2042-2065. [PMID: 28539408 PMCID: PMC5509419 DOI: 10.1091/mbc.e16-09-0644] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 05/18/2017] [Accepted: 05/18/2017] [Indexed: 12/15/2022] Open
Abstract
During embryo morphogenesis, minor epithelia are generated after, and then form bridges between, major epithelia (e.g., epidermis and gut). In Caenorhabditis elegans, this delay is regulated by four proteins that control production and localization of polarity proteins: the pioneer factor PHA-4/FoxA, kinesin ZEN-4/MKLP1, its partner CYK-4/MgcRacGAP, and PAR-6. To establish the animal body plan, embryos link the external epidermis to the internal digestive tract. In Caenorhabditis elegans, this linkage is achieved by the arcade cells, which form an epithelial bridge between the foregut and epidermis, but little is known about how development of these three epithelia is coordinated temporally. The arcade cell epithelium is generated after the epidermis and digestive tract epithelia have matured, ensuring that both organs can withstand the mechanical stress of embryo elongation; mistiming of epithelium formation leads to defects in morphogenesis. Using a combination of genetic, bioinformatic, and imaging approaches, we find that temporal regulation of the arcade cell epithelium is mediated by the pioneer transcription factor and master regulator PHA-4/FoxA, followed by the cytoskeletal regulator and kinesin ZEN-4/MKLP1 and the polarity protein PAR-6. We show that PHA-4 directly activates mRNA expression of a broad cohort of epithelial genes, including junctional factor dlg-1. Accumulation of DLG-1 protein is delayed by ZEN-4, acting in concert with its binding partner CYK-4/MgcRacGAP. Our structure–function analysis suggests that nuclear and kinesin functions are dispensable, whereas binding to CYK-4 is essential, for ZEN-4 function in polarity. Finally, PAR-6 is necessary to localize polarity proteins such as DLG-1 within adherens junctions and at the apical surface, thereby generating arcade cell polarity. Our results reveal that the timing of a landmark event during embryonic morphogenesis is mediated by the concerted action of four proteins that delay the formation of an epithelial bridge until the appropriate time. In addition, we find that mammalian FoxA associates with many epithelial genes, suggesting that direct regulation of epithelial identity may be a conserved feature of FoxA factors and a contributor to FoxA function in development and cancer.
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Affiliation(s)
- Stephen E Von Stetina
- Department of Molecular and Cellular Biology, Harvard University, Cambridge; MA 02138
| | - Jennifer Liang
- Department of Molecular and Cellular Biology, Harvard University, Cambridge; MA 02138
| | - Georgios Marnellos
- Informatics and Scientific Applications, Science Division, Faculty of Arts and Sciences, Harvard University, Cambridge; MA 02138
| | - Susan E Mango
- Department of Molecular and Cellular Biology, Harvard University, Cambridge; MA 02138
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23
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Breznau EB, Murt M, Blasius TL, Verhey KJ, Miller AL. The MgcRacGAP SxIP motif tethers Centralspindlin to microtubule plus ends in Xenopus laevis. J Cell Sci 2017; 130:1809-1821. [PMID: 28389580 DOI: 10.1242/jcs.195891] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 04/04/2017] [Indexed: 12/27/2022] Open
Abstract
Centralspindlin, a complex of the kinesin-6-family member MKLP1 and MgcRacGAP (also known as Kif23 and Racgap1, respectively), is required for cytokinesis and cell-cell junctions. During anaphase, Centralspindlin accumulates at overlapping central spindle microtubules and directs contractile ring formation by recruiting the GEF Ect2 to the cell equator to activate RhoA. We found that MgcRacGAP localized to the plus ends of equatorial astral microtubules during cytokinesis in Xenopus laevis embryos. How MgcRacGAP is stabilized at microtubule plus ends is unknown. We identified an SxIP motif in X. laevis MgcRacGAP that is conserved with other proteins that bind to EB1 (also known as Mapre1), a microtubule plus-end tracking protein. Mutation of the SxIP motif in MgcRacGAP resulted in loss of MgcRacGAP tracking with EB3 (also known as Mapre3) on growing microtubule plus ends, abnormal astral microtubule organization, redistribution of MgcRacGAP from the contractile ring to the polar cell cortex, and mislocalization of RhoA and its downstream targets, which together contributed to severe cytokinesis defects. Furthermore, mutation of the MgcRacGAP SxIP motif perturbed adherens junctions. We propose that the MgcRacGAP SxIP motif is functionally important both for its role in regulating adherens junction structure during interphase and for regulating Rho GTPase activity during cytokinesis.
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Affiliation(s)
- Elaina B Breznau
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Megan Murt
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - T Lynne Blasius
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Kristen J Verhey
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Ann L Miller
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48109, USA .,Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
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24
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Arnold TR, Stephenson RE, Miller AL. Rho GTPases and actomyosin: Partners in regulating epithelial cell-cell junction structure and function. Exp Cell Res 2017; 358:20-30. [PMID: 28363828 DOI: 10.1016/j.yexcr.2017.03.053] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 03/25/2017] [Accepted: 03/27/2017] [Indexed: 01/11/2023]
Abstract
Epithelial tissues are defined by polarized epithelial cells that are integrated into tissues and exhibit barrier function in order to regulate what is allowed to pass between cells. Cell-cell junctions must be stable enough to promote barrier function and tissue integrity, yet plastic enough to remodel when necessary. This remarkable ability to dynamically sense and respond to changes in cell shape and tissue tension allows cell-cell junctions to remain functional during events that disrupt epithelial homeostasis including morphogenesis, wound healing, and cell division. In order to achieve this plasticity, both tight junctions and adherens junctions are coupled to the underlying actomyosin cytoskeleton. Here, we discuss the importance of the junctional linkage to actomyosin and how a localized zone of active RhoA along with other Rho GTPases work together to orchestrate junctional actomyosin dynamics. We focus on how scaffold proteins help coordinate Rho GTPases, their upstream regulators, and their downstream effectors for efficient, localized Rho GTPase signaling output. Additionally, we highlight important roles junctional actin-binding proteins play in addition to their traditional roles in organizing actin. Together, Rho GTPases, their regulators, and effectors form compartmentalized signaling modules that regulate actomyosin structure and contractility to achieve proper cell-cell adhesion and tissue barriers.
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Affiliation(s)
- Torey R Arnold
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, United States
| | - Rachel E Stephenson
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, United States
| | - Ann L Miller
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, United States.
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25
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Mangan AJ, Sietsema DV, Li D, Moore JK, Citi S, Prekeris R. Cingulin and actin mediate midbody-dependent apical lumen formation during polarization of epithelial cells. Nat Commun 2016; 7:12426. [PMID: 27484926 PMCID: PMC4976216 DOI: 10.1038/ncomms12426] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 07/01/2016] [Indexed: 12/26/2022] Open
Abstract
Coordinated polarization of epithelial cells is a key step during morphogenesis that leads to the formation of an apical lumen. Rab11 and its interacting protein FIP5 are necessary for the targeting of apical endosomes to the midbody and apical membrane initiation site (AMIS) during lumenogenesis. However, the machinery that mediates AMIS establishment and FIP5-endosome targeting remains unknown. Here we identify a FIP5-interacting protein, Cingulin, which localizes to the AMIS and functions as a tether mediating FIP5-endosome targeting. We analysed the machinery mediating AMIS recruitment to the midbody and determined that both branched actin and microtubules are required for establishing the site of the nascent lumen. We demonstrate that the Rac1-WAVE/Scar complex mediates Cingulin recruitment to the AMIS by inducing branched actin formation, and that Cingulin directly binds to microtubule C-terminal tails through electrostatic interactions. We propose a new mechanism for apical endosome targeting and AMIS formation around the midbody during epithelial lumenogenesis. Polarisation of epithelial cells causes lumen formation, which is mediated by apical membrane initiation site (AMIS) and FIP5, but how this is regulated is unclear. Here, the authors identify cingulin as a FIP-5 interacting protein, recruiting the Rac1-WAVE/Scar complex to the AMIS and branched actin formation.
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Affiliation(s)
- Anthony J Mangan
- Department of Cell and Developmental Biology, School of Medicine, Anschutz Medical Campus, University of Colorado Denver, Aurora, Colorado 80045, USA
| | - Daniel V Sietsema
- Department of Cell and Developmental Biology, School of Medicine, Anschutz Medical Campus, University of Colorado Denver, Aurora, Colorado 80045, USA
| | - Dongying Li
- Department of Cell and Developmental Biology, School of Medicine, Anschutz Medical Campus, University of Colorado Denver, Aurora, Colorado 80045, USA
| | - Jeffrey K Moore
- Department of Cell and Developmental Biology, School of Medicine, Anschutz Medical Campus, University of Colorado Denver, Aurora, Colorado 80045, USA
| | - Sandra Citi
- Cell Biology Department, University of Geneva, CH-1211 GENEVA 4, Switzerland
| | - Rytis Prekeris
- Department of Cell and Developmental Biology, School of Medicine, Anschutz Medical Campus, University of Colorado Denver, Aurora, Colorado 80045, USA
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26
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Involvement of Tight Junction Plaque Proteins in Cancer. CURRENT PATHOBIOLOGY REPORTS 2016. [DOI: 10.1007/s40139-016-0108-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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27
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Balda MS, Matter K. Tight junctions as regulators of tissue remodelling. Curr Opin Cell Biol 2016; 42:94-101. [PMID: 27236618 DOI: 10.1016/j.ceb.2016.05.006] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Revised: 05/08/2016] [Accepted: 05/10/2016] [Indexed: 12/20/2022]
Abstract
Formation of tissue barriers by epithelial and endothelial cells requires neighbouring cells to interact via intercellular junctions, which includes tight junctions. Tight junctions form a semipermeable paracellular diffusion barrier and act as signalling hubs that guide cell behaviour and differentiation. Components of tight junctions are also expressed in cell types not forming tight junctions, such as cardiomyocytes, where they associate with facia adherens and/or gap junctions. This review will focus on tight junction proteins and their importance in tissue homeostasis and remodelling with a particular emphasis on what we have learned from animal models and human diseases.
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Affiliation(s)
- Maria S Balda
- Department of Cell Biology, UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Karl Matter
- Department of Cell Biology, UCL Institute of Ophthalmology, University College London, London, United Kingdom
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Guerrera D, Shah J, Vasileva E, Sluysmans S, Méan I, Jond L, Poser I, Mann M, Hyman AA, Citi S. PLEKHA7 Recruits PDZD11 to Adherens Junctions to Stabilize Nectins. J Biol Chem 2016; 291:11016-29. [PMID: 27044745 DOI: 10.1074/jbc.m115.712935] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Indexed: 01/07/2023] Open
Abstract
PLEKHA7 is a junctional protein implicated in stabilization of the cadherin protein complex, hypertension, cardiac contractility, glaucoma, microRNA processing, and susceptibility to bacterial toxins. To gain insight into the molecular basis for the functions of PLEKHA7, we looked for new PLEKHA7 interactors. Here, we report the identification of PDZ domain-containing protein 11 (PDZD11) as a new interactor of PLEKHA7 by yeast two-hybrid screening and by mass spectrometry analysis of PLEKHA7 immunoprecipitates. We show that PDZD11 (17 kDa) is expressed in epithelial and endothelial cells, where it forms a complex with PLEKHA7, as determined by co-immunoprecipitation analysis. The N-terminal Trp-Trp (WW) domain of PLEKHA7 interacts directly with the N-terminal 44 amino acids of PDZD11, as shown by GST-pulldown assays. Immunofluorescence analysis shows that PDZD11 is localized at adherens junctions in a PLEKHA7-dependent manner, because its junctional localization is abolished by knock-out of PLEKHA7, and is rescued by re-expression of exogenous PLEKHA7. The junctional recruitment of nectin-1 and nectin-3 and their protein levels are decreased via proteasome-mediated degradation in epithelial cells where either PDZD11 or PLEKHA7 have been knocked-out. PDZD11 forms a complex with nectin-1 and nectin-3, and its PDZ domain interacts directly with the PDZ-binding motif of nectin-1. PDZD11 is required for the efficient assembly of apical junctions of epithelial cells at early time points in the calcium-switch model. These results show that the PLEKHA7-PDZD11 complex stabilizes nectins to promote efficient early junction assembly and uncover a new molecular mechanism through which PLEKHA7 recruits PDZ-binding membrane proteins to epithelial adherens junctions.
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Affiliation(s)
- Diego Guerrera
- From the Department of Cell Biology and Institute for Genetics and Genomics in Geneva (iGE3), University of Geneva, 1211-4 Geneva, Switzerland
| | - Jimit Shah
- From the Department of Cell Biology and Institute for Genetics and Genomics in Geneva (iGE3), University of Geneva, 1211-4 Geneva, Switzerland
| | - Ekaterina Vasileva
- From the Department of Cell Biology and Institute for Genetics and Genomics in Geneva (iGE3), University of Geneva, 1211-4 Geneva, Switzerland
| | - Sophie Sluysmans
- From the Department of Cell Biology and Institute for Genetics and Genomics in Geneva (iGE3), University of Geneva, 1211-4 Geneva, Switzerland
| | - Isabelle Méan
- From the Department of Cell Biology and Institute for Genetics and Genomics in Geneva (iGE3), University of Geneva, 1211-4 Geneva, Switzerland
| | - Lionel Jond
- From the Department of Cell Biology and Institute for Genetics and Genomics in Geneva (iGE3), University of Geneva, 1211-4 Geneva, Switzerland
| | - Ina Poser
- the Max Planck Institute for Cell Biology and Genetics, 01307 Dresden, Germany, and
| | - Matthias Mann
- the Max Planck Institute for Biochemistry, 82152 Martinsried, Germany
| | - Anthony A Hyman
- the Max Planck Institute for Cell Biology and Genetics, 01307 Dresden, Germany, and
| | - Sandra Citi
- From the Department of Cell Biology and Institute for Genetics and Genomics in Geneva (iGE3), University of Geneva, 1211-4 Geneva, Switzerland,
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Schossleitner K, Rauscher S, Gröger M, Friedl HP, Finsterwalder R, Habertheuer A, Sibilia M, Brostjan C, Födinger D, Citi S, Petzelbauer P. Evidence That Cingulin Regulates Endothelial Barrier Function In Vitro and In Vivo. Arterioscler Thromb Vasc Biol 2016; 36:647-54. [PMID: 26821949 DOI: 10.1161/atvbaha.115.307032] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 01/14/2016] [Indexed: 01/24/2023]
Abstract
OBJECTIVE Cingulin is a cytoplasmic component of tight junctions. Although modulation of cingulin levels in cultured epithelial model systems has no significant effect on barrier function, evidence from cingulin knockout mice suggests that cingulin may be involved in the regulation of the behavior of epithelial or endothelial cells. Here, we investigate the role of cingulin in the barrier function of endothelial cells. APPROACH AND RESULTS We show that cingulin is expressed in human endothelial cells of the skin, brain, and lung in vivo and in vitro. Endothelial cingulin colocalizes and coimmunoprecipitates with the tight junction proteins zonula occludens-1 and guanine nucleotide exchange factor-H1. Cingulin overexpression in human umbilical vein endothelial cell induces tight junction formation, increases transendothelial electric resistance, and strengthens barrier function for low and high molecular weight tracers. In contrast, cultured endothelial cells lacking cingulin are more permeable for low molecular weight tracers. In cingulin knockout mice, neurons of the area postrema and Purkinje cells show an increased uptake of small molecular weight tracers indicating decreased barrier function at these sites. CONCLUSIONS We demonstrate that cingulin participates in the modulation of endothelial barrier function both in human cultured cells in vitro and in mouse brains in vivo. Understanding the role of cingulin in maintaining tight barriers in endothelia may allow developing new strategies for the treatment of vascular leak syndromes.
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Affiliation(s)
- Klaudia Schossleitner
- From the Skin and Endothelium Research Division (SERD), Department of Dermatology (K.S., S.R., M.G., H.P.F., R.F., P.P.), Core Facility Imaging (S.R., M.G.), Department of Cardiac Surgery (A.H.), Department of Medicine I, Institute of Cancer Research, Comprehensive Cancer Center (M.S.), Department of Surgery (C.B.), and Department of Dermatology (D.F.), Medical University of Vienna, Vienna, Austria; and Department of Cell Biology and Institute of Genetics and Genomics in Geneva, University of Geneva, Switzerland (S.C.)
| | - Sabine Rauscher
- From the Skin and Endothelium Research Division (SERD), Department of Dermatology (K.S., S.R., M.G., H.P.F., R.F., P.P.), Core Facility Imaging (S.R., M.G.), Department of Cardiac Surgery (A.H.), Department of Medicine I, Institute of Cancer Research, Comprehensive Cancer Center (M.S.), Department of Surgery (C.B.), and Department of Dermatology (D.F.), Medical University of Vienna, Vienna, Austria; and Department of Cell Biology and Institute of Genetics and Genomics in Geneva, University of Geneva, Switzerland (S.C.)
| | - Marion Gröger
- From the Skin and Endothelium Research Division (SERD), Department of Dermatology (K.S., S.R., M.G., H.P.F., R.F., P.P.), Core Facility Imaging (S.R., M.G.), Department of Cardiac Surgery (A.H.), Department of Medicine I, Institute of Cancer Research, Comprehensive Cancer Center (M.S.), Department of Surgery (C.B.), and Department of Dermatology (D.F.), Medical University of Vienna, Vienna, Austria; and Department of Cell Biology and Institute of Genetics and Genomics in Geneva, University of Geneva, Switzerland (S.C.)
| | - Heinz Peter Friedl
- From the Skin and Endothelium Research Division (SERD), Department of Dermatology (K.S., S.R., M.G., H.P.F., R.F., P.P.), Core Facility Imaging (S.R., M.G.), Department of Cardiac Surgery (A.H.), Department of Medicine I, Institute of Cancer Research, Comprehensive Cancer Center (M.S.), Department of Surgery (C.B.), and Department of Dermatology (D.F.), Medical University of Vienna, Vienna, Austria; and Department of Cell Biology and Institute of Genetics and Genomics in Geneva, University of Geneva, Switzerland (S.C.)
| | - Richard Finsterwalder
- From the Skin and Endothelium Research Division (SERD), Department of Dermatology (K.S., S.R., M.G., H.P.F., R.F., P.P.), Core Facility Imaging (S.R., M.G.), Department of Cardiac Surgery (A.H.), Department of Medicine I, Institute of Cancer Research, Comprehensive Cancer Center (M.S.), Department of Surgery (C.B.), and Department of Dermatology (D.F.), Medical University of Vienna, Vienna, Austria; and Department of Cell Biology and Institute of Genetics and Genomics in Geneva, University of Geneva, Switzerland (S.C.)
| | - Andreas Habertheuer
- From the Skin and Endothelium Research Division (SERD), Department of Dermatology (K.S., S.R., M.G., H.P.F., R.F., P.P.), Core Facility Imaging (S.R., M.G.), Department of Cardiac Surgery (A.H.), Department of Medicine I, Institute of Cancer Research, Comprehensive Cancer Center (M.S.), Department of Surgery (C.B.), and Department of Dermatology (D.F.), Medical University of Vienna, Vienna, Austria; and Department of Cell Biology and Institute of Genetics and Genomics in Geneva, University of Geneva, Switzerland (S.C.)
| | - Maria Sibilia
- From the Skin and Endothelium Research Division (SERD), Department of Dermatology (K.S., S.R., M.G., H.P.F., R.F., P.P.), Core Facility Imaging (S.R., M.G.), Department of Cardiac Surgery (A.H.), Department of Medicine I, Institute of Cancer Research, Comprehensive Cancer Center (M.S.), Department of Surgery (C.B.), and Department of Dermatology (D.F.), Medical University of Vienna, Vienna, Austria; and Department of Cell Biology and Institute of Genetics and Genomics in Geneva, University of Geneva, Switzerland (S.C.)
| | - Christine Brostjan
- From the Skin and Endothelium Research Division (SERD), Department of Dermatology (K.S., S.R., M.G., H.P.F., R.F., P.P.), Core Facility Imaging (S.R., M.G.), Department of Cardiac Surgery (A.H.), Department of Medicine I, Institute of Cancer Research, Comprehensive Cancer Center (M.S.), Department of Surgery (C.B.), and Department of Dermatology (D.F.), Medical University of Vienna, Vienna, Austria; and Department of Cell Biology and Institute of Genetics and Genomics in Geneva, University of Geneva, Switzerland (S.C.)
| | - Dagmar Födinger
- From the Skin and Endothelium Research Division (SERD), Department of Dermatology (K.S., S.R., M.G., H.P.F., R.F., P.P.), Core Facility Imaging (S.R., M.G.), Department of Cardiac Surgery (A.H.), Department of Medicine I, Institute of Cancer Research, Comprehensive Cancer Center (M.S.), Department of Surgery (C.B.), and Department of Dermatology (D.F.), Medical University of Vienna, Vienna, Austria; and Department of Cell Biology and Institute of Genetics and Genomics in Geneva, University of Geneva, Switzerland (S.C.)
| | - Sandra Citi
- From the Skin and Endothelium Research Division (SERD), Department of Dermatology (K.S., S.R., M.G., H.P.F., R.F., P.P.), Core Facility Imaging (S.R., M.G.), Department of Cardiac Surgery (A.H.), Department of Medicine I, Institute of Cancer Research, Comprehensive Cancer Center (M.S.), Department of Surgery (C.B.), and Department of Dermatology (D.F.), Medical University of Vienna, Vienna, Austria; and Department of Cell Biology and Institute of Genetics and Genomics in Geneva, University of Geneva, Switzerland (S.C.)
| | - Peter Petzelbauer
- From the Skin and Endothelium Research Division (SERD), Department of Dermatology (K.S., S.R., M.G., H.P.F., R.F., P.P.), Core Facility Imaging (S.R., M.G.), Department of Cardiac Surgery (A.H.), Department of Medicine I, Institute of Cancer Research, Comprehensive Cancer Center (M.S.), Department of Surgery (C.B.), and Department of Dermatology (D.F.), Medical University of Vienna, Vienna, Austria; and Department of Cell Biology and Institute of Genetics and Genomics in Geneva, University of Geneva, Switzerland (S.C.).
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Abstract
The establishment and maintenance of epithelial cell-cell junctions is crucially important to regulate adhesion, apico-basal polarity and motility of epithelial cells, and ultimately controls the architecture and physiology of epithelial organs. Junctions are supported, shaped and regulated by cytoskeletal filaments, whose dynamic organization and contractility are finely tuned by GTPases of the Rho family, primarily RhoA, Rac1 and Cdc42. Recent research has identified new molecular mechanisms underlying the cross-talk between these GTPases and epithelial junctions. Here we briefly summarize the current knowledge about the organization, molecular evolution and cytoskeletal anchoring of cell-cell junctions, and we comment on the most recent advances in the characterization of the interactions between Rho GTPases and junctional proteins, and their consequences with regards to junction assembly and regulation of cell behavior in vertebrate model systems. The concept of “zonular signalosome” is proposed, which highlights the close functional relationship between proteins of zonular junctions (zonulae occludentes and adhaerentes) and the control of cytoskeletal organization and signaling through Rho GTPases, transcription factors, and their effectors.
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Key Words
- AJ, adherens junction
- AMOT, angiomotin
- AMPK, Adenosine Monophosphate-Activated Protein Kinase
- APC, adenomatous poliposis coli
- CD2AP, CD2-associated protein
- CGN, cingulin
- CGNL1, paracingulin
- Cdc42
- Cdc42, cell division cycle 42
- DLC, deleted in liver cancer
- Dbl, diffuse B-cell lymphoma
- EPLIN, epithelial protein lost in neoplasm
- ERK, extracellular regulated kinase
- FERM, four.point.one, ezrin, radixin, moesin
- FGD5, FYVE, RhoGEF and PH domain containing 5
- GAP, GTPase activating protein
- GEF, guanine nucleotide exchange factor
- GST, glutathione -S- transferase; JAM = junctional adhesion molecule
- MCF-7, Michigan Cancer Foundation - 7
- MDCK, Madin Darby Canine Kidney
- MKLP1, mitotic kinesin-like protein-1
- MRCK, myotonic dystrophy-related Cdc42-binding kinase
- MgcRacGAP, male germ cell racGAP
- PA, puncta adhaerentia
- PAK, p21-activated kinase; PATJ, Pals1 associated tight junction protein
- PCNA, proliferating cell nuclear antigen
- PDZ, Post synaptic density protein (PSD95), Drosophila, disc large tumour suppressor (DlgA), and zonula occludens-1
- PLEKHA7, pleckstrin homology domain containing, family A member 7
- RICH-1, RhoGAP interacting with CIP4 homologues
- ROCK, Rho-associated protein kinase
- Rac
- Rho
- SH3BP1, (SH3 domain 490 binding protein-1)
- TJ, tight junction
- Tbx-3, T-box-3
- Tiam, Tumor invasion and metastasis
- WASP, Wiskott-Aldrich Syndrome Protein
- WAVE, WASP family Verprolin-homologous protein
- ZA, zonula adhaerens
- ZO, zonula occludens
- ZONAB, (ZO-1)–associated nucleic acid binding protein.
- cytoseleton
- epithelium
- junctions
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Affiliation(s)
- Sandra Citi
- a Department of Cell Biology ; University of Geneva ; Geneva , Switzerland
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31
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Tille JC, Ho L, Shah J, Seyde O, McKee TA, Citi S. The Expression of the Zonula Adhaerens Protein PLEKHA7 Is Strongly Decreased in High Grade Ductal and Lobular Breast Carcinomas. PLoS One 2015; 10:e0135442. [PMID: 26270346 PMCID: PMC4535953 DOI: 10.1371/journal.pone.0135442] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 07/22/2015] [Indexed: 01/11/2023] Open
Abstract
PLEKHA7 is a junctional protein, which participates in a complex that stabilizes E-cadherin at the zonula adhaerens. Since E-cadherin is involved in epithelial morphogenesis, signaling, and tumor progression, we explored PLEKHA7 expression in cancer. PLEKHA7 expression was assessed in invasive ductal and lobular carcinomas of the breast by immunohistochemistry, immunofluorescence and quantitative RT-PCR. PLEKHA7 was detected at epithelial junctions of normal mammary ducts and lobules, and of tubular and micropapillary structures within G1 and G2 ductal carcinomas. At these junctions, the localization of PLEKHA7 was along the circumferential belt (zonula adhaerens), and only partially overlapping with that of E-cadherin, p120ctn and ZO-1, as shown previously in rodent tissues. PLEKHA7 immunolabeling was strongly decreased in G3 ductal carcinomas and undetectable in lobular carcinomas. PLEKHA7 mRNA was detected in both ductal and lobular carcinomas, with no observed correlation between mRNA levels and tumor type or grade. In summary, PLEKHA7 is a junctional marker of epithelial cells within tubular structures both in normal breast tissue and ductal carcinomas, and since PLEKHA7 protein but not mRNA expression is strongly decreased or lost in high grade ductal carcinomas and in lobular carcinomas, loss of PLEKHA7 is a newly characterized feature of these carcinomas.
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Affiliation(s)
| | - Liza Ho
- Division of Clinical Pathology, Geneva University Hospitals, Geneva, Switzerland
| | - Jimit Shah
- Department of Cell Biology, University of Geneva, Geneva, Switzerland
- Institute of Genomics and Genetics of Geneva (iGE3), University of Geneva, Geneva, Switzerland
| | - Olivia Seyde
- Division of Clinical Pathology, Geneva University Hospitals, Geneva, Switzerland
| | - Thomas A. McKee
- Division of Clinical Pathology, Geneva University Hospitals, Geneva, Switzerland
| | - Sandra Citi
- Department of Cell Biology, University of Geneva, Geneva, Switzerland
- Institute of Genomics and Genetics of Geneva (iGE3), University of Geneva, Geneva, Switzerland
- * E-mail:
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Jia Z, Johnson AC, Wang X, Guo Z, Dreisbach AW, Lewin JR, Kyle PB, Garrett MR. Allelic Variants in Arhgef11 via the Rho-Rock Pathway Are Linked to Epithelial-Mesenchymal Transition and Contributes to Kidney Injury in the Dahl Salt-Sensitive Rat. PLoS One 2015; 10:e0132553. [PMID: 26172442 PMCID: PMC4501567 DOI: 10.1371/journal.pone.0132553] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 06/17/2015] [Indexed: 12/21/2022] Open
Abstract
Previously, genetic analyses identified that variants in Arhgef11 may influence kidney injury in the Dahl salt-sensitive (S) rat, a model of hypertensive chronic kidney disease. To understand the potential mechanism by which altered expression and/or protein differences in Arhgef11 could play a role in kidney injury, stably transduced Arhgef11 knockdown cell lines as well as primary cultures of proximal tubule cells were studied. Genetic knockdown of Arhgef11 in HEK293 and NRK resulted in reduced RhoA activity, decreased activation of Rho-ROCK pathway, and less stress fiber formation versus control, similar to what was observed by pharmacological inhibition (fasudil). Primary proximal tubule cells (PTC) cultured from the S exhibited increased expression of Arhgef11, increased RhoA activity, and up regulation of Rho-ROCK signaling compared to control (small congenic). The cells were also more prone (versus control) to TGFβ-1 induced epithelial-mesenchymal transition (EMT), a hallmark feature of the development of renal interstitial fibrosis, and characterized by development of spindle shape morphology, gene expression changes in EMT markers (Col1a3, Mmp9, Bmp7, and Ocln) and increased expression of N-Cadherin and Vimentin. S derived PTC demonstrated a decreased ability to uptake FITC-albumin compared to the small congenic in vitro, which was confirmed by assessment of albumin re-uptake in vivo by infusion of FITC-albumin and immunofluorescence imaging. In summary, these studies suggest that genetic variants in the S form of Arhgef11 via increased expression and/or protein activity play a role in promoting kidney injury in the S rat through changes in cell morphology (Rho-Rock and/or EMT) that impact the function of tubule cells.
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Affiliation(s)
- Zhen Jia
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, United States of America
| | - Ashley C. Johnson
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, United States of America
| | - Xuexiang Wang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, United States of America
| | - Zibiao Guo
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, United States of America
- Molecular and Genomics Core Facility, University of Mississippi Medical Center, Jackson, MS, United States of America
| | - Albert W. Dreisbach
- Department of Medicine (Nephrology), University of Mississippi Medical Center, Jackson, MS, United States of America
| | - Jack R. Lewin
- Department of Pathology, University of Mississippi Medical Center, Jackson, MS, United States of America
| | - Patrick B. Kyle
- Department of Pathology, University of Mississippi Medical Center, Jackson, MS, United States of America
| | - Michael R. Garrett
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS, United States of America
- Department of Medicine (Nephrology), University of Mississippi Medical Center, Jackson, MS, United States of America
- * E-mail:
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33
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Zihni C, Balda MS, Matter K. Signalling at tight junctions during epithelial differentiation and microbial pathogenesis. J Cell Sci 2015; 127:3401-13. [PMID: 25125573 DOI: 10.1242/jcs.145029] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Tight junctions are a component of the epithelial junctional complex, and they form the paracellular diffusion barrier that enables epithelial cells to create cellular sheets that separate compartments with different compositions. The assembly and function of tight junctions are intimately linked to the actomyosin cytoskeleton and, hence, are under the control of signalling mechanisms that regulate cytoskeletal dynamics. Tight junctions not only receive signals that guide their assembly and function, but transmit information to the cell interior to regulate cell proliferation, migration and survival. As a crucial component of the epithelial barrier, they are often targeted by pathogenic viruses and bacteria, aiding infection and the development of disease. In this Commentary, we review recent progress in the understanding of the molecular signalling mechanisms that drive junction assembly and function, and the signalling processes by which tight junctions regulate cell behaviour and survival. We also discuss the way in which junctional components are exploited by pathogenic viruses and bacteria, and how this might affect junctional signalling mechanisms.
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Affiliation(s)
- Ceniz Zihni
- Department of Cell Biology, UCL Institute of Ophthalmology, University College London, Bath Street, London EC1V 9EL, UK
| | - Maria S Balda
- Department of Cell Biology, UCL Institute of Ophthalmology, University College London, Bath Street, London EC1V 9EL, UK
| | - Karl Matter
- Department of Cell Biology, UCL Institute of Ophthalmology, University College London, Bath Street, London EC1V 9EL, UK
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Breznau EB, Semack AC, Higashi T, Miller AL. MgcRacGAP restricts active RhoA at the cytokinetic furrow and both RhoA and Rac1 at cell-cell junctions in epithelial cells. Mol Biol Cell 2015; 26:2439-55. [PMID: 25947135 PMCID: PMC4571299 DOI: 10.1091/mbc.e14-11-1553] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 04/30/2015] [Indexed: 12/17/2022] Open
Abstract
MgcRacGAP's role in regulating the spatiotemporal dynamics of active RhoA and Rac1 in epithelial cells is investigated. MgcRacGAP's GAP activity down-regulates RhoA at the furrow and both RhoA and Rac1 at cell–cell junctions in dividing epithelial cells and is required for successful cytokinesis and cell–cell junction structure. MgcRacGAP's ability to regulate adherens junctions is dependent on GAP activity and signaling via the RhoA pathway. Localized activation of Rho GTPases is essential for multiple cellular functions, including cytokinesis and formation and maintenance of cell–cell junctions. Although MgcRacGAP (Mgc) is required for spatially confined RhoA-GTP at the equatorial cortex of dividing cells, both the target specificity of Mgc's GAP activity and the involvement of phosphorylation of Mgc at Ser-386 are controversial. In addition, Mgc's function at cell–cell junctions remains unclear. Here, using gastrula-stage Xenopus laevis embryos as a model system, we examine Mgc's role in regulating localized RhoA-GTP and Rac1-GTP in the intact vertebrate epithelium. We show that Mgc's GAP activity spatially restricts accumulation of both RhoA-GTP and Rac1-GTP in epithelial cells—RhoA at the cleavage furrow and RhoA and Rac1 at cell–cell junctions. Phosphorylation at Ser-386 does not switch the specificity of Mgc's GAP activity and is not required for successful cytokinesis. Furthermore, Mgc regulates adherens junction but not tight junction structure, and the ability to regulate adherens junctions is dependent on GAP activity and signaling via the RhoA pathway. Together these results indicate that Mgc's GAP activity down-regulates the active populations of RhoA and Rac1 at localized regions of epithelial cells and is necessary for successful cytokinesis and cell–cell junction structure.
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Affiliation(s)
- Elaina B Breznau
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48109
| | - Ansley C Semack
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Tomohito Higashi
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
| | - Ann L Miller
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48109 Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109
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F-actin binding protein, anillin, regulates integrity of intercellular junctions in human epithelial cells. Cell Mol Life Sci 2015; 72:3185-3200. [PMID: 25809162 DOI: 10.1007/s00018-015-1890-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 02/26/2015] [Accepted: 03/19/2015] [Indexed: 01/01/2023]
Abstract
Tight junctions (TJ) and adherens junctions (AJ) are key morphological features of differentiated epithelial cells that regulate the integrity and permeability of tissue barriers. Structure and remodeling of epithelial junctions depends on their association with the underlying actomyosin cytoskeleton. Anillin is a unique scaffolding protein interacting with different cytoskeletal components, including actin filaments and myosin motors. Its role in the regulation of mammalian epithelial junctions remains unexplored. Downregulation of anillin expression in human prostate, colonic, and lung epithelial cells triggered AJ and TJ disassembly without altering the expression of junctional proteins. This junctional disassembly was accompanied by dramatic disorganization of the perijunctional actomyosin belt; while the general architecture of the actin cytoskeleton, and activation status of non-muscle myosin II, remained unchanged. Furthermore, loss of anillin disrupted the adducin-spectrin membrane skeleton at the areas of cell-cell contact, selectively decreased γ-adducin expression, and induced cytoplasmic aggregation of αII-spectrin. Anillin knockdown activated c-Jun N-terminal kinase (JNK), and JNK inhibition restored AJ and TJ integrity and cytoskeletal organization in anillin-depleted cells. These findings suggest a novel role for anillin in regulating intercellular adhesion in model human epithelia by mechanisms involving the suppression of JNK activity and controlling the assembly of the perijunctional cytoskeleton.
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36
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Gehren AS, Rocha MR, de Souza WF, Morgado-Díaz JA. Alterations of the apical junctional complex and actin cytoskeleton and their role in colorectal cancer progression. Tissue Barriers 2015; 3:e1017688. [PMID: 26451338 DOI: 10.1080/21688370.2015.1017688] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 01/31/2015] [Accepted: 02/06/2015] [Indexed: 01/08/2023] Open
Abstract
Colorectal cancer represents the fourth highest mortality rate among cancer types worldwide. An understanding of the molecular mechanisms that regulate their progression can prevents or reduces mortality due to this disease. Epithelial cells present an apical junctional complex connected to the actin cytoskeleton, which maintains the dynamic properties of this complex, tissue architecture and cell homeostasis. Several studies have indicated that apical junctional complex alterations and actin cytoskeleton disorganization play a critical role in epithelial cancer progression. However, few studies have examined the existence of an interrelation between these 2 components, particularly in colorectal cancer. This review discusses the recent progress toward elucidating the role of alterations of apical junctional complex constituents and of modifications of actin cytoskeleton organization and discusses how these events are interlinked to modulate cellular responses related to colorectal cancer progression toward successful metastasis.
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Affiliation(s)
- Adriana Sartorio Gehren
- Program of Cellular Biology; Brazilian National Cancer Institute (INCA) ; Rio de Janeiro, Brazil
| | - Murilo Ramos Rocha
- Program of Cellular Biology; Brazilian National Cancer Institute (INCA) ; Rio de Janeiro, Brazil
| | | | - José Andrés Morgado-Díaz
- Program of Cellular Biology; Brazilian National Cancer Institute (INCA) ; Rio de Janeiro, Brazil
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Quiros M, Nusrat A. RhoGTPases, actomyosin signaling and regulation of the epithelial Apical Junctional Complex. Semin Cell Dev Biol 2014; 36:194-203. [PMID: 25223584 DOI: 10.1016/j.semcdb.2014.09.003] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Revised: 08/28/2014] [Accepted: 09/04/2014] [Indexed: 12/22/2022]
Abstract
Epithelial cells form regulated and selective barriers between distinct tissue compartments. The Apical Junctional Complex (AJC) consisting of the tight junction (TJ) and adherens junction (AJ) control epithelial homeostasis, paracellular permeability and barrier properties. The AJC is composed of mutliprotein complexes consisting of transmembrane proteins that affiliate with an underlying perijunctional F-actin myosin ring through cytoplasmic scaffold proteins. AJC protein associations with the apical actin-myosin cytoskeleton are tightly controlled by a number of signaling proteins including the Rho family of GTPases that orchestrate junctional biology, epithelial homeostasis and barrier function. This review highlights the vital relationship of Rho GTPases and AJCs in controlling the epithelial barrier. The pathophysiologic relationship of Rho GTPases, AJC, apical actomyosin cytoskeleton and epithelial barrier function is discussed.
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Affiliation(s)
- Miguel Quiros
- Epithelial Pathobiology and Mucosal Inflammation Research Unit, Department of Pathology & Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Asma Nusrat
- Epithelial Pathobiology and Mucosal Inflammation Research Unit, Department of Pathology & Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA.
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Van Itallie CM, Anderson JM. Architecture of tight junctions and principles of molecular composition. Semin Cell Dev Biol 2014; 36:157-65. [PMID: 25171873 DOI: 10.1016/j.semcdb.2014.08.011] [Citation(s) in RCA: 359] [Impact Index Per Article: 35.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 08/15/2014] [Accepted: 08/19/2014] [Indexed: 12/11/2022]
Abstract
The tight junction creates an intercellular barrier limiting paracellular movement of solutes and material across epithelia. Currently many proteins have been identified as components of the tight junction and understanding their architectural organization and interactions is critical to understanding the biology of the barrier. In general the architecture can be conceptualized into compartments with the transmembrane barrier proteins (claudins, occludin, JAM-A, etc.), linked to peripheral scaffolding proteins (such as ZO-1, afadin, MAGI1, etc.) which are in turned linked to actin and microtubules through numerous linkers (cingulin, myosins, protein 4.1, etc.). Within this complex network are associated many signaling proteins that affect the barrier and broader cell functions. The PDZ domain is a commonly used motif to specifically link individual junction protein pairs. Here we review some of the key proteins defining the tight junction and general themes of their organization with the perspective that much will be learned about function by characterizing the detailed architecture and subcompartments within the junction.
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Affiliation(s)
- Christina M Van Itallie
- The Laboratory of Tight Junction Structure and Function, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 50, Room 4525, 50 South Drive, Bethesda, MD 20892, USA.
| | - James M Anderson
- The Laboratory of Tight Junction Structure and Function, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 50, Room 4525, 50 South Drive, Bethesda, MD 20892, USA.
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Ngok SP, Lin WH, Anastasiadis PZ. Establishment of epithelial polarity--GEF who's minding the GAP? J Cell Sci 2014; 127:3205-15. [PMID: 24994932 DOI: 10.1242/jcs.153197] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Cell polarization is a fundamental process that underlies epithelial morphogenesis, cell motility, cell division and organogenesis. Loss of polarity predisposes tissues to developmental disorders and contributes to cancer progression. The formation and establishment of epithelial cell polarity is mediated by the cooperation of polarity protein complexes, namely the Crumbs, partitioning defective (Par) and Scribble complexes, with Rho family GTPases, including RhoA, Rac1 and Cdc42. The activation of different GTPases triggers distinct downstream signaling pathways to modulate protein-protein interactions and cytoskeletal remodeling. The spatio-temporal activation and inactivation of these small GTPases is tightly controlled by a complex interconnected network of different regulatory proteins, including guanine-nucleotide-exchange factors (GEFs), GTPase-activating proteins (GAPs), and guanine-nucleotide-dissociation inhibitors (GDIs). In this Commentary, we focus on current understanding on how polarity complexes interact with GEFs and GAPs to control the precise location and activation of Rho GTPases (Crumbs for RhoA, Par for Rac1, and Scribble for Cdc42) to promote apical-basal polarization in mammalian epithelial cells. The mutual exclusion of GTPase activities, especially that of RhoA and Rac1, which is well established, provides a mechanism through which polarity complexes that act through distinct Rho GTPases function as cellular rheostats to fine-tune specific downstream pathways to differentiate and preserve the apical and basolateral domains. This article is part of a Minifocus on Establishing polarity.
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Affiliation(s)
- Siu P Ngok
- Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Griffin Cancer Research Building, Room 307, 4500 San Pablo Road, Jacksonville, FL 32224, USA
| | - Wan-Hsin Lin
- Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Griffin Cancer Research Building, Room 307, 4500 San Pablo Road, Jacksonville, FL 32224, USA
| | - Panos Z Anastasiadis
- Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Griffin Cancer Research Building, Room 307, 4500 San Pablo Road, Jacksonville, FL 32224, USA
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