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Rietscher K, Homberg M, Kovalenko I, Sexton JZ, Rice RH, Has C, Omary MB, Magin TM. Painting and dissecting Epidermolysis Bullosa Simplex-associated keratin aggregates. J Dermatol Sci 2023; 112:109-111. [PMID: 37735021 DOI: 10.1016/j.jdermsci.2023.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/26/2023] [Accepted: 08/09/2023] [Indexed: 09/23/2023]
Affiliation(s)
- Katrin Rietscher
- Institute of Biology, Professorship of Cell and Developmental Biology, University of Leipzig, Leipzig, Germany.
| | - Melanie Homberg
- Institute of Biology, Professorship of Cell and Developmental Biology, University of Leipzig, Leipzig, Germany
| | - Ilya Kovalenko
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, USA; Department of Internal Medicine, Gastroenterology and Hepatology, Michigan Medicine at the University of Michigan, Ann Arbor, MI, USA; U-M Center for Drug Repurposing, University of Michigan, Ann Arbor, MI, USA; Insilico Medicine HK Limited, Pak Shek Kok, Hong Kong
| | - Jonathan Z Sexton
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI, USA; Department of Internal Medicine, Gastroenterology and Hepatology, Michigan Medicine at the University of Michigan, Ann Arbor, MI, USA; U-M Center for Drug Repurposing, University of Michigan, Ann Arbor, MI, USA
| | - Robert H Rice
- Department of Environmental Toxicology, University of California, Davis, CA, USA; Forensic Science Program, University of California, Davis, CA, USA
| | - Cristina Has
- Department of Dermatology, Medical Center, University of Freiburg, Freiburg, Germany
| | - M Bishr Omary
- Center for Advanced Biotechnology and Medicine, and Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, USA
| | - Thomas M Magin
- Institute of Biology, Professorship of Cell and Developmental Biology, University of Leipzig, Leipzig, Germany
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2
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Rietscher K, Jahnke HG, Rübsam M, Lin EW, Has C, Omary MB, Niessen CM, Magin TM. Kinase Inhibition by PKC412 Prevents Epithelial Sheet Damage in Autosomal Dominant Epidermolysis Bullosa Simplex through Keratin and Cell Contact Stabilization. J Invest Dermatol 2022; 142:3282-3293. [PMID: 35691363 DOI: 10.1016/j.jid.2022.05.1088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 04/24/2022] [Accepted: 05/22/2022] [Indexed: 01/05/2023]
Abstract
Epidermolysis bullosa simplex (EBS) is a severe and potentially life-threatening disorder for which no adequate therapy exists. Most cases are caused by dominant sequence variations in keratin genes K5 or K14, leading to the formation of cytoplasmic keratin aggregates, profound keratinocyte fragility, and cytolysis. We hypothesized that pharmacological reduction of keratin aggregates, which compromise keratinocyte integrity, represents a viable strategy for the treatment of EBS. In this study, we show that the multikinase inhibitor PKC412, which is currently in clinical use for acute myeloid leukemia and advanced systemic mastocytosis, reduced keratin aggregation by 40% in patient-derived K14.R125C EBS-associated keratinocytes. Using a combination of epithelial shear stress assay and real-time impedance spectroscopy, we show that PKC412 restored intercellular adhesion. Molecularly, global phosphoproteomic analysis together with immunoblots using phosphoepitope-specific antibodies revealed that PKC412 treatment altered phosphorylated sites on keratins and desmoplakin. Thus, our data provide a proof of concept to repurpose existing drugs for the targeted treatment of EBS and showcase how one broad-range kinase inhibitor reduced keratin filament aggregation in patient-derived EBS keratinocytes and the fragility of EBS cell monolayers. Our study paves the way for a clinical trial using PKC412 for systemic or local application in patients with EBS.
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Affiliation(s)
- Katrin Rietscher
- Institute of Biology, Division of Cell and Developmental Biology, Leipzig University, Leipzig, Germany.
| | - Heinz-Georg Jahnke
- Division of Molecular Biological-Biochemical Processing Technology, Center for Biotechnology and Biomedicine, Leipzig University, Leipzig, Germany
| | - Matthias Rübsam
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany; Department Cell Biology of the Skin, Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Eric W Lin
- Division of Gastroenterology and Hepatology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Cristina Has
- Department of Dermatology, Medical Center, University of Freiburg, Freiburg, Germany
| | - M Bishr Omary
- Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, New Jersey, USA; Robert Wood Johnson Medical School, Rutgers University, New Brunswick, New Jersey, USA
| | - Carien M Niessen
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany; Department Cell Biology of the Skin, Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Thomas M Magin
- Institute of Biology, Division of Cell and Developmental Biology, Leipzig University, Leipzig, Germany
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Human Hair Keratin Composite Scaffold: Characterisation and Biocompatibility Study on NIH 3T3 Fibroblast Cells. Pharmaceuticals (Basel) 2021; 14:ph14080781. [PMID: 34451878 PMCID: PMC8401710 DOI: 10.3390/ph14080781] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Revised: 08/06/2021] [Accepted: 08/06/2021] [Indexed: 12/27/2022] Open
Abstract
The aim of this study was to transform human hair keratin waste into a scaffold for soft tissue engineering to heal wounds. The keratin was extracted using the Shindai method. Keratin and polyvinyl alcohol (PVA) was cross-linked with alginate dialdehyde and converted into a scaffold by the freeze-drying method using gentamycin sulphate (GS) as a model drug. The scaffold was subjected to Fourier transform infrared spectra (FTIR), swelling index, porosity, water absorption, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), drug release, and cell viability (MTT) analysis. The scaffold was tested for keratinocyte growth using the murine fibroblast cell line (NIH 3T3 cells). The outcome from the keratin had a molecular weight band between 52-38 kDa in SDS-PAGE (Sodium dodecylsulfate-Polyacrylamide gel electrophoresis). A porous scaffold was capable of water absorption (73.64 ± 14.29%), swelling ability (68.93 ± 1.33%), and the release of GS shown as 97.45 ± 4.57 and 93.86 ± 5.22 of 1:4 and 1:3 scaffolds at 16 h. The physicochemical evaluation revealed that the prepared scaffold exhibits the proper structural integrity: partially crystalline with a strong thermal property. The scaffold demonstrated better cell viability against the murine fibroblast cell line (NIH 3T3 cells). In conclusion, we found that the prepared composite scaffold (1:4) can be used for wound healing applications.
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Benoit B, Baillet A, Poüs C. Cytoskeleton and Associated Proteins: Pleiotropic JNK Substrates and Regulators. Int J Mol Sci 2021; 22:8375. [PMID: 34445080 PMCID: PMC8395060 DOI: 10.3390/ijms22168375] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/28/2021] [Accepted: 07/30/2021] [Indexed: 12/12/2022] Open
Abstract
This review extensively reports data from the literature concerning the complex relationships between the stress-induced c-Jun N-terminal kinases (JNKs) and the four main cytoskeleton elements, which are actin filaments, microtubules, intermediate filaments, and septins. To a lesser extent, we also focused on the two membrane-associated cytoskeletons spectrin and ESCRT-III. We gather the mechanisms controlling cytoskeleton-associated JNK activation and the known cytoskeleton-related substrates directly phosphorylated by JNK. We also point out specific locations of the JNK upstream regulators at cytoskeletal components. We finally compile available techniques and tools that could allow a better characterization of the interplay between the different types of cytoskeleton filaments upon JNK-mediated stress and during development. This overview may bring new important information for applied medical research.
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Affiliation(s)
- Béatrice Benoit
- Université Paris-Saclay, INSERM UMR-S-1193, 5 Rue Jean-Baptiste Clément, 92296 Châtenay-Malabry, France; (A.B.); (C.P.)
| | - Anita Baillet
- Université Paris-Saclay, INSERM UMR-S-1193, 5 Rue Jean-Baptiste Clément, 92296 Châtenay-Malabry, France; (A.B.); (C.P.)
| | - Christian Poüs
- Université Paris-Saclay, INSERM UMR-S-1193, 5 Rue Jean-Baptiste Clément, 92296 Châtenay-Malabry, France; (A.B.); (C.P.)
- Biochimie-Hormonologie, AP-HP Université Paris-Saclay, Site Antoine Béclère, 157 Rue de la Porte de Trivaux, 92141 Clamart, France
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5
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MacTaggart B, Kashina A. Posttranslational modifications of the cytoskeleton. Cytoskeleton (Hoboken) 2021; 78:142-173. [PMID: 34152688 DOI: 10.1002/cm.21679] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 06/13/2021] [Accepted: 06/16/2021] [Indexed: 12/12/2022]
Abstract
The cytoskeleton plays important roles in many essential processes at the cellular and organismal levels, including cell migration and motility, cell division, and the establishment and maintenance of cell and tissue architecture. In order to facilitate these varied functions, the main cytoskeletal components-microtubules, actin filaments, and intermediate filaments-must form highly diverse intracellular arrays in different subcellular areas and cell types. The question of how this diversity is conferred has been the focus of research for decades. One key mechanism is the addition of posttranslational modifications (PTMs) to the major cytoskeletal proteins. This posttranslational addition of various chemical groups dramatically increases the complexity of the cytoskeletal proteome and helps facilitate major global and local cytoskeletal functions. Cytoskeletal proteins undergo many PTMs, most of which are not well understood. Recent technological advances in proteomics and cell biology have allowed for the in-depth study of individual PTMs and their functions in the cytoskeleton. Here, we provide an overview of the major PTMs that occur on the main structural components of the three cytoskeletal systems-tubulin, actin, and intermediate filament proteins-and highlight the cellular function of these modifications.
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Affiliation(s)
- Brittany MacTaggart
- School of Veterinary Medicine, Department of Biomedical Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Anna Kashina
- School of Veterinary Medicine, Department of Biomedical Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Lee SY, Kim S, Lim Y, Yoon HN, Ku NO. Keratins regulate Hsp70-mediated nuclear localization of p38 mitogen-activated protein kinase. J Cell Sci 2019; 132:jcs.229534. [PMID: 31427430 DOI: 10.1242/jcs.229534] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 08/12/2019] [Indexed: 12/31/2022] Open
Abstract
Intermediate filament protein keratin 8 (K8) binds to heat shock protein 70 (Hsp70) and p38 MAPK, and is phosphorylated at Ser74 by p38α (MAPK14, hereafter p38). However, a p38 binding site on K8 and the molecular mechanism of K8-p38 interaction related to Hsp70 are unknown. Here, we identify a p38 docking site on K8 (Arg148/149 and Leu159/161) that is highly conserved in other intermediate filaments. A docking-deficient K8 mutation caused increased p38-Hsp70 interaction and enhanced p38 nuclear localization, indicating that the p38 dissociated from mutant K8 makes a complex with Hsp70, which is known as a potential chaperone for p38 nuclear translocation. Comparison of p38 MAPK binding with keratin variants associated with liver disease showed that the K18 I150V variant dramatically reduced binding with p38, which is similar to the effect of the p38 docking-deficient mutation on K8. Because the p38 docking site on K8 (Arg148/149 and Leu159/161) and the K18 Ile150 residue are closely localized in the parallel K8/K18 heterodimer, the K18 I150V mutation might interfere with K8-p38 interaction. These findings show that keratins, functioning as cytoplasmic anchors for p38, modulate p38 nuclear localization and thereby might affect a number of p38-mediated signal transduction pathways.
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Affiliation(s)
- So-Young Lee
- Interdisciplinary Program of Integrated OMICS for Biomedical Science, Graduate School, Yonsei University, Seoul 120-749, Korea
| | - Sujin Kim
- Interdisciplinary Program of Integrated OMICS for Biomedical Science, Graduate School, Yonsei University, Seoul 120-749, Korea
| | - Younglan Lim
- Interdisciplinary Program of Integrated OMICS for Biomedical Science, Graduate School, Yonsei University, Seoul 120-749, Korea
| | - Han-Na Yoon
- Interdisciplinary Program of Integrated OMICS for Biomedical Science, Graduate School, Yonsei University, Seoul 120-749, Korea
| | - Nam-On Ku
- Interdisciplinary Program of Integrated OMICS for Biomedical Science, Graduate School, Yonsei University, Seoul 120-749, Korea .,Department of Bio-Convergence ISED, Underwood International College, Yonsei University, Seoul 120-749, Korea
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7
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High Proliferative Placenta-Derived Multipotent Cells Express Cytokeratin 7 at Low Level. BIOMED RESEARCH INTERNATIONAL 2019; 2019:2098749. [PMID: 31392209 PMCID: PMC6662495 DOI: 10.1155/2019/2098749] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 05/30/2019] [Accepted: 06/25/2019] [Indexed: 12/11/2022]
Abstract
The purpose of this study was to investigate the immunophenotypes and gene expression profile of high proliferative placenta-derived multipotent cells (PDMCs) population at different stages of culture. We demonstrated that the colonies resulting from single cells were either positive or negative for CK7, whereas only PDMC clones with weak CK7 expression (CK7low-clones) were highly proliferative. Interestingly, vimentin positive (Vim+) placental stromal mesenchymal cells did not express CK7 in situ, but double CK7+Vim+ cells detection in tissue explants and explants outgrowth indicated CK7 inducible expression in vitro. PCNA presence in CK7+Vim+ cells during placental explants culturing confirmed belonging of these cells to proliferative subpopulation. Transcription factors CDX2 and EOMES were expressed in both CK7low-clones and subset of stromal mesenchymal cells of first-trimester placental tissue in situ. Meanwhile, CK7low -clones and stromal mesenchymal cells of full-term placental tissue in situ expressed ERG heterogeneously. SPP1, COL2A1, and PPARG2 mesodermal-related genes expression by CK7low-clones additionally confirms their mesenchymal origin. Inherent stem cell-related gene expression (IFTM3, POU5F1, and VASA) in CK7low-clones might indicate their enrichment for progenitors. Finally, in CK7low-clones we observed expression of such trophoblast-associated genes as CGB types I and II, fusogenic ERVW-1, GCM1, and GATA3. Thus, our results indicate that PDMCs acquired the representative immunophenotype signature under culture conditions.
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Abstract
Intermediate filaments (IFs) are one of the three major elements of the cytoskeleton. Their stability, intrinsic mechanical properties, and cell type-specific expression patterns distinguish them from actin and microtubules. By providing mechanical support, IFs protect cells from external forces and participate in cell adhesion and tissue integrity. IFs form an extensive and elaborate network that connects the cell cortex to intracellular organelles. They act as a molecular scaffold that controls intracellular organization. However, IFs have been revealed as much more than just rigid structures. Their dynamics is regulated by multiple signaling cascades and appears to contribute to signaling events in response to cell stress and to dynamic cellular functions such as mitosis, apoptosis, and migration.
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Affiliation(s)
- Sandrine Etienne-Manneville
- Institut Pasteur Paris, CNRS UMR 3691, Cell Polarity, Migration and Cancer Unit, Equipe Labellisée Ligue Contre le Cancer, Paris Cedex 15, France;
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9
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Inaba H, Yamakawa D, Tomono Y, Enomoto A, Mii S, Kasahara K, Goto H, Inagaki M. Regulation of keratin 5/14 intermediate filaments by CDK1, Aurora-B, and Rho-kinase. Biochem Biophys Res Commun 2018. [DOI: 10.1016/j.bbrc.2018.03.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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10
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Arcidiacono P, Webb CM, Brooke MA, Zhou H, Delaney PJ, Ng KE, Blaydon DC, Tinker A, Kelsell DP, Chikh A. p63 is a key regulator of iRHOM2 signalling in the keratinocyte stress response. Nat Commun 2018; 9:1021. [PMID: 29523849 PMCID: PMC5844915 DOI: 10.1038/s41467-018-03470-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 02/14/2018] [Indexed: 02/06/2023] Open
Abstract
Hyperproliferative keratinocytes induced by trauma, hyperkeratosis and/or inflammation display molecular signatures similar to those of palmoplantar epidermis. Inherited gain-of-function mutations in RHBDF2 (encoding iRHOM2) are associated with a hyperproliferative palmoplantar keratoderma and squamous oesophageal cancer syndrome (termed TOC). In contrast, genetic ablation of rhbdf2 in mice leads to a thinning of the mammalian footpad, and reduces keratinocyte hyperproliferation and migration. Here, we report that iRHOM2 is a novel target gene of p63 and that both p63 and iRHOM2 differentially regulate cellular stress-associated signalling pathways in normal and hyperproliferative keratinocytes. We demonstrate that p63-iRHOM2 regulates cell survival and response to oxidative stress via modulation of SURVIVIN and Cytoglobin, respectively. Furthermore, the antioxidant compound Sulforaphane downregulates p63-iRHOM2 expression, leading to reduced proliferation, inflammation, survival and ROS production. These findings elucidate a novel p63-associated pathway that identifies iRHOM2 modulation as a potential therapeutic target to treat hyperproliferative skin disease and neoplasia.
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Affiliation(s)
- Paola Arcidiacono
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, E1 2AT, UK
| | - Catherine M Webb
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, E1 2AT, UK
| | - Matthew A Brooke
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, E1 2AT, UK
| | - Huiqing Zhou
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
- Department of Molecular Developmental Biology, Radboud University, Nijmegen, The Netherlands
| | - Paul J Delaney
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, E1 2AT, UK
| | - Keat-Eng Ng
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, E1 2AT, UK
| | - Diana C Blaydon
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, E1 2AT, UK
| | - Andrew Tinker
- The Heart Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, Charterhouse Square, London, EC1M 6BQ, UK
| | - David P Kelsell
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, E1 2AT, UK.
| | - Anissa Chikh
- Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, E1 2AT, UK.
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Duverger O, Carlson JC, Karacz CM, Schwartz ME, Cross MA, Marazita ML, Shaffer JR, Morasso MI. Genetic variants in pachyonychia congenita-associated keratins increase susceptibility to tooth decay. PLoS Genet 2018; 14:e1007168. [PMID: 29357356 PMCID: PMC5794186 DOI: 10.1371/journal.pgen.1007168] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 02/01/2018] [Accepted: 12/25/2017] [Indexed: 12/24/2022] Open
Abstract
Pachyonychia congenita (PC) is a cutaneous disorder primarily characterized by nail dystrophy and painful palmoplantar keratoderma. PC is caused by mutations in KRT6A, KRT6B, KRT6C, KRT16, and KRT17, a set of keratin genes expressed in the nail bed, palmoplantar epidermis, oral mucosal epithelium, hair follicle and sweat gland. RNA-seq analysis revealed that all PC-associated keratins (except for Krt6c that does exist in the mouse genome) are expressed in the mouse enamel organ. We further demonstrated that these keratins are produced by ameloblasts and are incorporated into mature human enamel. Using genetic and intraoral examination data from 573 adults and 449 children, we identified several missense polymorphisms in KRT6A, KRT6B and KRT6C that lead to a higher risk for dental caries. Structural analysis of teeth from a PC patient carrying a p.Asn171Lys substitution in keratin-6a (K6a) revealed disruption of enamel rod sheaths resulting in altered rod shape and distribution. Finally, this PC-associated substitution as well as more frequent caries-associated SNPs, found in two of the KRT6 genes, that result in p.Ser143Asn substitution (rs28538343 in KRT6B and rs151117600 in KRT6C), alter the assembly of K6 filaments in ameloblast-like cells. These results identify a new set of keratins involved in tooth enamel formation, distinguish novel susceptibility loci for tooth decay and reveal additional clinical features of pachyonychia congenita. Tooth decay, more commonly known as dental cavities, is the most common chronic disease worldwide, both in children and in adults. It consists in the destruction of tooth enamel, the outer layer of the teeth, by acid-producing bacteria. Enamel is the hardest tissue in the body, comprised of 96% minerals. However, it contains a small fraction of proteins that is important for its resistance to mechanical stress and decay. Here we show that this protein fraction contains a set of structural proteins (K6a, K6b, K6c, K16 and K17) that belong to the keratin family and are present specifically in the skin of the palms and soles, as well as in nails. We further show that common genetic mutations that affect the composition of these proteins lead to an increased number of cavities. Rare mutations in these keratins lead to a human disease called pachyonychia congenita (PC) and characterized by severe nail malformations and lesions in the skin of the palms and soles. Analysis of wisdom teeth from one of these patients showed that their enamel exhibited structural defects. These results demonstrate that these keratins are important components of tooth enamel and that common genetic variants in the genes that encode them influence tooth decay risk in the general population.
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Affiliation(s)
- Olivier Duverger
- Laboratory of Skin Biology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Jenna C. Carlson
- Department of Human Genetics, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Biostatistics, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Chelsea M. Karacz
- Laboratory of Skin Biology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Mary E. Schwartz
- Pachyonychia Congenita Project, Holladay, UT, United States of America
| | - Michael A. Cross
- Laboratory of Skin Biology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, United States of America
| | - Mary L. Marazita
- Department of Human Genetics, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for Craniofacial and Dental Genetics, University of Pittsburgh, Pittsburgh, PA, United States of America
- Department of Oral Biology, School of Dental Medicine, Clinical and Translational Science Institute, Department of Psychiatry, School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - John R. Shaffer
- Department of Human Genetics, University of Pittsburgh, Pittsburgh, PA, United States of America
- Center for Craniofacial and Dental Genetics, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Maria I. Morasso
- Laboratory of Skin Biology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, United States of America
- * E-mail:
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12
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Waters M, VandeVord P, Van Dyke M. Keratin biomaterials augment anti-inflammatory macrophage phenotype in vitro. Acta Biomater 2018; 66:213-223. [PMID: 29107632 DOI: 10.1016/j.actbio.2017.10.042] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 10/19/2017] [Accepted: 10/27/2017] [Indexed: 12/16/2022]
Abstract
Tissue regeneration following injury is mediated by macrophage recruitment and differentiation in response to environmental signals. In general, macrophages adopt either a classically M1 (M[IFN-γ, LPS]) or alternatively activated M2 (M[IL-4, IL-13] or M[IL-10]) phenotype. Recent studies have highlighted the importance of alternatively activated macrophages in tissue remodeling and repair as well as the contribution of an imbalance of classically and alternatively activated macrophages to tissue degeneration and disease progression. Keratin biomaterials have recently demonstrated their ability to promote alternatively activated macrophage polarization in an in vitro model using a monocytic cell line. In the present study, the ability of extracted human hair keratins to influence alternative activation of human primary monocytes in vitro is assessed by evaluating changes in surface receptor expression, inflammatory cytokine secretion, and phagocytic activity. The impact of keratin molecular weight fractionation on these outcomes was also investigated. High and low molecular weight fractions of the oxidized form of extractable human hair keratins - referred to as keratose (KOSH and KOSP, respectively) - were characterized by size exclusion chromatography, mass spectrometry, and Western blot. Primary macrophages underwent traditional differentiation to the M[IFN-γ, LPS], M[IL-4, IL-13], or M[IL-10]) phenotypes or were plated on different molecular weight keratin coatings (KOSH and KOSP). Macrophages plated on keratin and analyzed via flow cytometry yielded the largest CD163+ cell populations and CD163 mean fluorescence intensities. Cells in the KOSP group were significantly more phagocytic than all other cell types at the 1.5 and 3 h time points and exhibited behavior and a cytokine production profile most similar to the M[IL-10] treated group. These findings may have important implications for understanding and evaluating the ability of keratin biomaterials to influence inflammation and tissue regeneration in disease and injury models. STATEMENT OF SIGNIFICANCE Biomaterials made from human hair keratins have previously been shown to elicit anti-inflammatory responses from naïve macrophages and polarize them toward an M2 phenotype. In this work we show for the first time that primary human cells respond similarly, that it is the M2c phenotype that predominates, that a sub-fraction of hydrolyzed keratin peptides are most likely responsible for the response, and that immobilization of the keratin peptides to a surface is required. Keratin biomaterials have been used to regenerate several tissues such as skin, muscle, bone, nerve, and cornea, in vitro and in animal studies. Our current findings will help guide the development of keratin-based biomaterials that seek to direct responses toward regenerative outcomes by attenuating inflammation.
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Affiliation(s)
- Michele Waters
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, United States; School of Biomedical Engineering and Sciences (SBES), Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, United States
| | - Pamela VandeVord
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, United States
| | - Mark Van Dyke
- Department of Biomedical Engineering and Mechanics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, United States.
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13
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Sawant M, Schwarz N, Windoffer R, Magin TM, Krieger J, Mücke N, Obara B, Jankowski V, Jankowski J, Wally V, Lettner T, Leube RE. Threonine 150 Phosphorylation of Keratin 5 Is Linked to Epidermolysis Bullosa Simplex and Regulates Filament Assembly and Cell Viability. J Invest Dermatol 2017; 138:627-636. [PMID: 29080682 DOI: 10.1016/j.jid.2017.10.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 09/11/2017] [Accepted: 10/08/2017] [Indexed: 10/18/2022]
Abstract
A characteristic feature of the skin blistering disease epidermolysis bullosa simplex is keratin filament (KF) network collapse caused by aggregation of the basal epidermal keratin type II (KtyII) K5 and its type I partner keratin 14 (K14). Here, we examine the role of keratin phosphorylation in KF network rearrangement and cellular functions. We detect phosphorylation of the K5 head domain residue T150 in cytoplasmic epidermolysis bullosa simplex granules containing R125C K14 mutants. Expression of phosphomimetic T150D K5 mutants results in impaired KF formation in keratinocytes. The phenotype is enhanced upon combination with other phosphomimetic K5 head domain mutations. Remarkably, introduction of T150D K5 mutants into KtyII-lacking (KtyII-/-) keratinocytes prevents keratin network formation altogether. In contrast, phosphorylation-deficient T150A K5 leads to KFs with reduced branching and turnover. Assembly of T150D K5 is arrested at the heterotetramer stage coinciding with increased heat shock protein association. Finally, reduced cell viability and elevated response to stressors is noted in T150 mutant cells. Taken together, our findings identify T150 K5 phosphorylation as an important determinant of KF network formation and function with a possible role in epidermolysis bullosa simplex pathogenesis.
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Affiliation(s)
- Mugdha Sawant
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Aachen, Germany
| | - Nicole Schwarz
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Aachen, Germany
| | - Reinhard Windoffer
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Aachen, Germany
| | - Thomas M Magin
- Institute of Biology and Translational Center for Regenerative Medicine, University of Leipzig, Leipzig, Germany
| | - Jan Krieger
- Biophysics of Macromolecules, German Cancer Research Center, Heidelberg, Germany
| | - Norbert Mücke
- Biophysics of Macromolecules, German Cancer Research Center, Heidelberg, Germany
| | - Boguslaw Obara
- School of Engineering and Computing Sciences, Durham University, Durham, UK
| | - Vera Jankowski
- Institut für Molekulare Herz-Kreislaufforschung, RWTH Aachen University, Aachen, Germany
| | - Joachim Jankowski
- Institut für Molekulare Herz-Kreislaufforschung, RWTH Aachen University, Aachen, Germany; School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
| | - Verena Wally
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Thomas Lettner
- EB House Austria, Research Program for Molecular Therapy of Genodermatoses, Department of Dermatology, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Rudolf E Leube
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, Aachen, Germany.
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14
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Sanghvi-Shah R, Weber GF. Intermediate Filaments at the Junction of Mechanotransduction, Migration, and Development. Front Cell Dev Biol 2017; 5:81. [PMID: 28959689 PMCID: PMC5603733 DOI: 10.3389/fcell.2017.00081] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 08/30/2017] [Indexed: 01/04/2023] Open
Abstract
Mechanically induced signal transduction has an essential role in development. Cells actively transduce and respond to mechanical signals and their internal architecture must manage the associated forces while also being dynamically responsive. With unique assembly-disassembly dynamics and physical properties, cytoplasmic intermediate filaments play an important role in regulating cell shape and mechanical integrity. While this function has been recognized and appreciated for more than 30 years, continually emerging data also demonstrate important roles of intermediate filaments in cell signal transduction. In this review, with a particular focus on keratins and vimentin, the relationship between the physical state of intermediate filaments and their role in mechanotransduction signaling is illustrated through a survey of current literature. Association with adhesion receptors such as cadherins and integrins provides a critical interface through which intermediate filaments are exposed to forces from a cell's environment. As a consequence, these cytoskeletal networks are posttranslationally modified, remodeled and reorganized with direct impacts on local signal transduction events and cell migratory behaviors important to development. We propose that intermediate filaments provide an opportune platform for cells to both cope with mechanical forces and modulate signal transduction.
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Affiliation(s)
- Rucha Sanghvi-Shah
- Department of Biological Sciences, Rutgers University-NewarkNewark, NJ, United States
| | - Gregory F Weber
- Department of Biological Sciences, Rutgers University-NewarkNewark, NJ, United States
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15
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Maruthappu T, Chikh A, Fell B, Delaney PJ, Brooke MA, Levet C, Moncada-Pazos A, Ishida-Yamamoto A, Blaydon D, Waseem A, Leigh IM, Freeman M, Kelsell DP. Rhomboid family member 2 regulates cytoskeletal stress-associated Keratin 16. Nat Commun 2017; 8:14174. [PMID: 28128203 PMCID: PMC5290154 DOI: 10.1038/ncomms14174] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 12/06/2016] [Indexed: 12/13/2022] Open
Abstract
Keratin 16 (K16) is a cytoskeletal scaffolding protein highly expressed at pressure-bearing sites of the mammalian footpad. It can be induced in hyperproliferative states such as wound healing, inflammation and cancer. Here we show that the inactive rhomboid protease RHBDF2 (iRHOM2) regulates thickening of the footpad epidermis through its interaction with K16. K16 expression is absent in the thinned footpads of irhom2-/- mice compared with irhom2+/+mice, due to reduced keratinocyte proliferation. Gain-of-function mutations in iRHOM2 underlie Tylosis with oesophageal cancer (TOC), characterized by palmoplantar thickening, upregulate K16 with robust downregulation of its type II keratin binding partner, K6. By orchestrating the remodelling and turnover of K16, and uncoupling it from K6, iRHOM2 regulates the epithelial response to physical stress. These findings contribute to our understanding of the molecular mechanisms underlying hyperproliferation of the palmoplantar epidermis in both physiological and disease states, and how this 'stress' keratin is regulated.
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Affiliation(s)
- Thiviyani Maruthappu
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark Street, Whitechapel London E1 2AT, UK
| | - Anissa Chikh
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark Street, Whitechapel London E1 2AT, UK
| | - Benjamin Fell
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark Street, Whitechapel London E1 2AT, UK
| | - Paul J. Delaney
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark Street, Whitechapel London E1 2AT, UK
| | - Matthew A. Brooke
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark Street, Whitechapel London E1 2AT, UK
| | - Clemence Levet
- Sir William Dunn School of Pathology, South Parks Road, Oxford OX1 3RE, UK
| | | | | | - Diana Blaydon
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark Street, Whitechapel London E1 2AT, UK
| | - Ahmad Waseem
- Centre for Clinical and Diagnostic Oral Sciences, Institute of Dentistry, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London E1 2AT, UK
| | - Irene M. Leigh
- Centre for Centre Molecular Medicine, Clinical Research Centre, Ninewells Hospital and Medical School, Dundee DD1 9SY, UK
| | - Matthew Freeman
- Sir William Dunn School of Pathology, South Parks Road, Oxford OX1 3RE, UK
| | - David P. Kelsell
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark Street, Whitechapel London E1 2AT, UK
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16
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Foster MW, Gwinn WM, Kelly FL, Brass DM, Valente AM, Moseley MA, Thompson JW, Morgan DL, Palmer SM. Proteomic Analysis of Primary Human Airway Epithelial Cells Exposed to the Respiratory Toxicant Diacetyl. J Proteome Res 2017; 16:538-549. [PMID: 27966365 DOI: 10.1021/acs.jproteome.6b00672] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Occupational exposures to the diketone flavoring agent, diacetyl, have been associated with bronchiolitis obliterans, a rare condition of airway fibrosis. Model studies in rodents have suggested that the airway epithelium is a major site of diacetyl toxicity, but the effects of diacetyl exposure upon the human airway epithelium are poorly characterized. Here we performed quantitative LC-MS/MS-based proteomics to study the effects of repeated diacetyl vapor exposures on 3D organotypic cultures of human primary tracheobronchial epithelial cells. Using a label-free approach, we quantified approximately 3400 proteins and 5700 phosphopeptides in cell lysates across four independent donors. Altered expression of proteins and phosphopeptides were suggestive of loss of cilia and increased squamous differentiation in diacetyl-exposed cells. These phenomena were confirmed by immunofluorescence staining of culture cross sections. Hyperphosphorylation and cross-linking of basal cell keratins were also observed in diacetyl-treated cells, and we used parallel reaction monitoring to confidently localize and quantify previously uncharacterized sites of phosphorylation in keratin 6. Collectively, these data identify numerous molecular changes in the epithelium that may be important to the pathogenesis of flavoring-induced bronchiolitis obliterans. More generally, this study highlights the utility of quantitative proteomics for the study of in vitro models of airway injury and disease.
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Affiliation(s)
| | - William M Gwinn
- National Institute of Environmental Health Sciences , Research Triangle Park, North Carolina 27709, United States
| | | | | | | | | | | | - Daniel L Morgan
- National Institute of Environmental Health Sciences , Research Triangle Park, North Carolina 27709, United States
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17
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Consequences of Keratin Phosphorylation for Cytoskeletal Organization and Epithelial Functions. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2017; 330:171-225. [DOI: 10.1016/bs.ircmb.2016.09.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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18
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Tan TS, Ng YZ, Badowski C, Dang T, Common JEA, Lacina L, Szeverényi I, Lane EB. Assays to Study Consequences of Cytoplasmic Intermediate Filament Mutations: The Case of Epidermal Keratins. Methods Enzymol 2016; 568:219-53. [PMID: 26795473 DOI: 10.1016/bs.mie.2015.09.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
Abstract
The discovery of the causative link between keratin mutations and a growing number of human diseases opened the way for a better understanding of the function of the whole intermediate filament families of cytoskeleton proteins. This chapter describes analytical approaches to identification and interpretation of the consequences of keratin mutations, from the clinical and diagnostic level to cells in tissue culture. Intermediate filament pathologies can be accurately diagnosed from skin biopsies and DNA samples. The Human Intermediate Filament Database collates reported mutations in intermediate filament genes and their diseases, and can help clinicians to establish accurate diagnoses, leading to disease stratification for genetic counseling, optimal care delivery, and future mutation-aligned new therapies. Looking at the best-studied keratinopathy, epidermolysis bullosa simplex, the generation of cell lines mimicking keratinopathies is described, in which tagged mutant keratins facilitate live-cell imaging to make use of today's powerful enhanced light microscopy modalities. Cell stress assays such as cell spreading and cell migration in scratch wound assays can interrogate the consequences of the compromised cytoskeletal network. Application of extrinsic stresses, such as heat, osmotic, or mechanical stress, can enhance the differentiation of mutant keratin cells from wild-type cells. To bring the experiments to the next level, 3D organotypic human cultures can be generated, and even grafted onto the backs of immunodeficient mice for greater in vivo relevance. While development of these assays has focused on mutant K5/K14 cells, the approaches are often applicable to mutations in other intermediate filaments, reinforcing fundamental commonalities in spite of diverse clinical pathologies.
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Affiliation(s)
| | | | | | - Tram Dang
- Institute of Medical Biology, Singapore
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19
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Snider NT, Omary MB. Assays for Posttranslational Modifications of Intermediate Filament Proteins. Methods Enzymol 2015; 568:113-38. [PMID: 26795469 DOI: 10.1016/bs.mie.2015.09.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Intermediate filament (IF) proteins are known to be regulated by a number of posttranslational modifications (PTMs). Phosphorylation is the best-studied IF PTM, whereas ubiquitination, sumoylation, acetylation, glycosylation, ADP-ribosylation, farnesylation, and transamidation are less understood in functional terms but are known to regulate specific IFs under various contexts. The number and diversity of IF PTMs is certain to grow along with rapid advances in proteomic technologies. Therefore, the need for a greater understanding of the implications of PTMs to the structure, organization, and function of the IF cytoskeleton has become more apparent with the increased availability of data from global profiling studies of normal and diseased specimens. This chapter will provide information on established methods for the isolation and monitoring of IF PTMs along with the key reagents that are necessary to carry out these experiments.
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Affiliation(s)
- Natasha T Snider
- Department of Cell Biology and Physiology, University of North Carolina, Chapel Hill, North Carolina, USA.
| | - M Bishr Omary
- Department of Molecular & Integrative Physiology, Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA; VA Ann Arbor Healthcare System, Ann Arbor, Michigan, USA
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20
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Almeida FV, Walko G, McMillan JR, McGrath JA, Wiche G, Barber AH, Connelly JT. The cytolinker plectin regulates nuclear mechanotransduction in keratinocytes. J Cell Sci 2015; 128:4475-86. [PMID: 26527396 DOI: 10.1242/jcs.173435] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2015] [Accepted: 10/26/2015] [Indexed: 01/14/2023] Open
Abstract
The transmission of mechanical forces to the nucleus is important for intracellular positioning, mitosis and cell motility, yet the contribution of specific components of the cytoskeleton to nuclear mechanotransduction remains unclear. In this study, we examine how crosstalk between the cytolinker plectin and F-actin controls keratin network organisation and the 3D nuclear morphology of keratinocytes. Using micro-patterned surfaces to precisely manipulate cell shape, we find that cell adhesion and spreading regulate the size and shape of the nucleus. Disruption of the keratin cytoskeleton through loss of plectin facilitated greater nuclear deformation, which depended on acto-myosin contractility. Nuclear morphology did not depend on direct linkage of the keratin cytoskeleton with the nuclear membrane, rather loss of plectin reduced keratin filament density around the nucleus. We further demonstrate that keratinocytes have abnormal nuclear morphologies in the epidermis of plectin-deficient, epidermolysis bullosa simplex patients. Taken together, our data demonstrate that plectin is an essential regulator of nuclear morphology in vitro and in vivo and protects the nucleus from mechanical deformation.
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Affiliation(s)
- Filipe V Almeida
- School of Engineering and Materials Science, Queen Mary, University of London, London, E1 4NS UK Centre for Cell Biology and Cutaneous Research, Barts and the London School of Medicine and Dentistry, Queen Mary, University of London, London, E1 2AT UK
| | - Gernot Walko
- Centre for Stem Cells and Regenerative Medicine, King's College London, London, SE1 9RT UK
| | - James R McMillan
- The National Diagnostic EB Laboratory, Viapath, St Thomas' Hospital, London, SE1 7EH UK
| | - John A McGrath
- St John's Institute of Dermatology, King's College London (Guy's Campus), London, SE1 9RT UK
| | - Gerhard Wiche
- Max F. Perutz Laboratories, Department of Biochemistry and Cell Biology, University of Vienna, 1030 Vienna, Austria
| | - Asa H Barber
- School of Engineering and Materials Science, Queen Mary, University of London, London, E1 4NS UK
| | - John T Connelly
- Centre for Cell Biology and Cutaneous Research, Barts and the London School of Medicine and Dentistry, Queen Mary, University of London, London, E1 2AT UK
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21
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Szabo S, Wögenstein KL, Fuchs P. Functional and Genetic Analysis of Epiplakin in Epithelial Cells. Methods Enzymol 2015; 569:261-85. [PMID: 26778563 DOI: 10.1016/bs.mie.2015.06.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Epiplakin is a large member (>700 kDa) of the plakin protein family and exclusively expressed in epithelial cell types. Compared to other plakin proteins epiplakin exhibits an unusual structure as it consists entirely of a variable number of consecutive plakin repeat domains (13 in humans, 16 in mice). The only binding partners of epiplakin identified so far are keratins of simple as well as of stratified epithelia. Epiplakin-deficient mice show no obvious spontaneous phenotype. However, ex vivo studies using epiplakin-deficient primary cells indicated protective functions of epiplakin in response to stress. Recent studies using stress models for organs of the gastrointestinal tract revealed that epiplakin-deficient mice develop more pronounced pancreas and liver injuries than their wild-type littermates. In addition, impaired stress-induced keratin network reorganization was observed in the affected organs, and primary epiplakin-deficient hepatocytes showed reduced tolerance for forced keratin overexpression which could be rescued by a chemical chaperone. These findings indicate protective functions of epiplakin in chaperoning disease-induced keratin reorganization. In this review, we describe some of the methods we used to analyze epiplakin's function with the focus on biochemical and ex vivo techniques.
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Affiliation(s)
- Sandra Szabo
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Karl L Wögenstein
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Peter Fuchs
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Vienna Biocenter (VBC), Vienna, Austria.
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22
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Kim HJ, Choi WJ, Lee CH. Phosphorylation and Reorganization of Keratin Networks: Implications for Carcinogenesis and Epithelial Mesenchymal Transition. Biomol Ther (Seoul) 2015; 23:301-12. [PMID: 26157545 PMCID: PMC4489823 DOI: 10.4062/biomolther.2015.032] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 04/30/2015] [Accepted: 05/04/2015] [Indexed: 12/15/2022] Open
Abstract
Metastasis is one of hallmarks of cancer and a major cause of cancer death. Combatting metastasis is highly challenging. To overcome these difficulties, researchers have focused on physical properties of metastatic cancer cells. Metastatic cancer cells from patients are softer than benign cancer or normal cells. Changes of viscoelasticity of cancer cells are related to the keratin network. Unexpectedly, keratin network is dynamic and regulation of keratin network is important to the metastasis of cancer. Keratin is composed of heteropolymer of type I and II. Keratin connects from the plasma membrane to nucleus. Several proteins including kinases, and protein phosphatases bind to keratin intermediate filaments. Several endogenous compounds or toxic compounds induce phosphorylation and reorganization of keratin network in cancer cells, leading to increased migration. Continuous phosphorylation of keratin results in loss of keratin, which is one of the features of epithelial mesenchymal transition (EMT). Therefore, several proteins involved in phosphorylation and reorganization of keratin also have a role in EMT. It is likely that compounds controlling phosphorylation and reorganization of keratin are potential candidates for combating EMT and metastasis.
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Affiliation(s)
- Hyun Ji Kim
- BK21PLUS R-FIND team, College of Pharmacy, Dongguk University, Seoul 100-715, Republic of Korea
| | - Won Jun Choi
- BK21PLUS R-FIND team, College of Pharmacy, Dongguk University, Seoul 100-715, Republic of Korea
| | - Chang Hoon Lee
- BK21PLUS R-FIND team, College of Pharmacy, Dongguk University, Seoul 100-715, Republic of Korea
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23
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Snider NT, Omary MB. Post-translational modifications of intermediate filament proteins: mechanisms and functions. Nat Rev Mol Cell Biol 2014; 15:163-77. [PMID: 24556839 PMCID: PMC4079540 DOI: 10.1038/nrm3753] [Citation(s) in RCA: 374] [Impact Index Per Article: 37.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Intermediate filaments (IFs) are cytoskeletal and nucleoskeletal structures that provide mechanical and stress-coping resilience to cells, contribute to subcellular and tissue-specific biological functions, and facilitate intracellular communication. IFs, including nuclear lamins and those in the cytoplasm (keratins, vimentin, desmin, neurofilaments and glial fibrillary acidic protein, among others), are functionally regulated by post-translational modifications (PTMs). Proteomic advances highlight the enormous complexity and regulatory potential of IF protein PTMs, which include phosphorylation, glycosylation, sumoylation, acetylation and prenylation, with novel modifications becoming increasingly appreciated. Future studies will need to characterize their on-off mechanisms, crosstalk and utility as biomarkers and targets for diseases involving the IF cytoskeleton.
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Affiliation(s)
- Natasha T. Snider
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
| | - M. Bishr Omary
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan
- VA Ann Arbor Healthcare System, Ann Arbor, Michigan
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24
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Beyond expectations: novel insights into epidermal keratin function and regulation. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 311:265-306. [PMID: 24952920 DOI: 10.1016/b978-0-12-800179-0.00007-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The epidermis is a stratified epithelium that relies on its cytoskeleton and cell junctions to protect the body against mechanical injury, dehydration, and infections. Keratin intermediate filament proteins are involved in many of these functions by forming cell-specific cytoskeletal scaffolds crucial for the maintenance of cell and tissue integrity. In response to various stresses, the expression and organization of keratins are altered at transcriptional and posttranslational levels to restore tissue homeostasis. Failure to restore tissue homeostasis in the presence of keratin gene mutations results in acute and chronic skin disorders for which currently no rational therapies are available. Here, we review the recent progress on the role of keratins in cytoarchitecture, adhesion, signaling, and inflammation. By focusing on epidermal keratins, we illustrate the contribution of keratin isotypes to differentiated epithelial functions.
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25
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Gregor M, Osmanagic-Myers S, Burgstaller G, Wolfram M, Fischer I, Walko G, Resch GP, Jörgl A, Herrmann H, Wiche G. Mechanosensing through focal adhesion-anchored intermediate filaments. FASEB J 2013; 28:715-29. [PMID: 24347609 DOI: 10.1096/fj.13-231829] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Integrin-based mechanotransduction involves a complex focal adhesion (FA)-associated machinery that is able to detect and respond to forces exerted either through components of the extracellular matrix or the intracellular contractile actomyosin network. Here, we show a hitherto unrecognized regulatory role of vimentin intermediate filaments (IFs) in this process. By studying fibroblasts in which vimentin IFs were decoupled from FAs, either because of vimentin deficiency (V0) or loss of vimentin network anchorage due to deficiency in the cytolinker protein plectin (P0), we demonstrate attenuated activation of the major mechanosensor molecule FAK and its downstream targets Src, ERK1/2, and p38, as well as an up-regulation of the compensatory feedback loop acting on RhoA and myosin light chain. In line with these findings, we show strongly reduced FA turnover rates in P0 fibroblasts combined with impaired directional migration, formation of protrusions, and up-regulation of "stretched" high-affinity integrin complexes. By exploiting tension-independent conditions, we were able to mechanistically link these defects to diminished cytoskeletal tension in both P0 and V0 cells. Our data provide important new insights into molecular mechanisms underlying cytoskeleton-regulated mechanosensing, a feature that is fundamental for controlled cell movement and tumor progression.
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Affiliation(s)
- Martin Gregor
- 3Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohrgasse 9, A-1030 Vienna, Austria.
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26
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Snider NT, Park H, Omary MB. A conserved rod domain phosphotyrosine that is targeted by the phosphatase PTP1B promotes keratin 8 protein insolubility and filament organization. J Biol Chem 2013; 288:31329-37. [PMID: 24003221 DOI: 10.1074/jbc.m113.502724] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Post-translational modifications are important functional determinants for intermediate filament (IF) proteins. Phosphorylation of IF proteins regulates filament organization, solubility, and cell-protective functions. Most known IF protein phosphorylation sites are serines localized in the variable "head" and "tail" domain regions. By contrast, little is known about site-specific tyrosine phosphorylation or its implications on IF protein function. We used available proteomic data from large scale studies to narrow down potential phospho-tyrosine sites on the simple epithelial IF protein keratin 8 (K8). Validation of the predicted sites using a pan-phosphotyrosine and a site-specific antibody, which we generated, revealed that the highly conserved Tyr-267 in the K8 "rod" domain was basally phosphorylated. The charge at this site was critically important, as demonstrated by altered filament organization of site-directed mutants, Y267F and Y267D, the latter exhibiting significantly diminished solubility. Pharmacological inhibition of the protein-tyrosine phosphatase PTP1B increased K8 Tyr-267 phosphorylation, decreased solubility, and increased K8 filament bundling, whereas PTP1B overexpression had the opposite effects. Furthermore, there was significant co-localization between K8 and a "substrate-trapping" mutant of PTP1B (D181A). Because K8 Tyr-267 is conserved in many IFs (QYE motif), we tested the effect of the paralogous Tyr in glial fibrillary acidic protein (GFAP), which is mutated in Alexander disease (Y242D). Similar to K8, Y242D GFAP exhibited highly irregular filament organization and diminished solubility. Our results implicate the rod domain QYE motif tyrosine as an important determinant of IF assembly and solubility properties that can be dynamically modulated by phosphorylation.
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Affiliation(s)
- Natasha T Snider
- From the Departments of Molecular and Integrative Physiology and
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27
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Ultraviolet radiation effects on the proteome of skin cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013; 990:111-9. [PMID: 23378007 DOI: 10.1007/978-94-007-5896-4_8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Proteomic studies to date have had limited use as an investigative tool in the skin's response to UV radiation. These studies used cell lines and reconstructed skin and have shown evidence of cell injury with oxidative damage and stress induced heat shock proteins. Others changes included altered cytokeratin and cytoskeletal proteins with enhanced expression of TRIM29 as the keratinocytes regenerate. The associated DNA repair requires polη, Rad18/Rad16 and Rev1. In the whole animal these events would be associated with inflammation, remodelling of the epidermis and modulation of the immune response. Longer term changes include ageing and skin cancers such as melanoma, squamous cell carcinoma and basal cell carcinoma. In the future proteomics will be used to explore these important aspects of photobiology. Better characterisation of the proteins involved should lead to a greater understanding of the skin's response to UV radiation.
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Kwan R, Hanada S, Harada M, Strnad P, Li DH, Omary MB. Keratin 8 phosphorylation regulates its transamidation and hepatocyte Mallory-Denk body formation. FASEB J 2012; 26:2318-26. [PMID: 22362895 DOI: 10.1096/fj.11-198580] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Mallory-Denk bodies (MDBs) are hepatocyte inclusions that are associated with poor liver disease prognosis. The intermediate filament protein keratin 8 (K8) and its cross-linking by transglutaminase-2 (TG2) are essential for MDB formation. K8 hyperphosphorylation occurs in association with liver injury and MDB formation, but the link between keratin phosphorylation and MDB formation is unknown. We used a mutational approach to identify K8 Q70 as a residue that is important for K8 cross-linking to itself and other liver proteins. K8 cross-linking is markedly enhanced on treating cells with a phosphatase inhibitor and decreases dramatically on K8 S74A or Q70N mutation in the presence of phosphatase inhibition. K8 Q70 cross-linking, in the context of synthetic peptides or intact proteins transfected into cells, is promoted by phosphorylation at K8 S74 or by an S74D substitution and is inhibited by S74A mutation. Transgenic mice that express K8 S74A or a K8 G62C liver disease variant that inhibits K8 S74 phosphorylation have a markedly reduced ability to form MDBs. Our findings support a model in which the stress-triggered phosphorylation of K8 S74 induces K8 cross-linking by TG2, leading to MDB formation. These findings may extend to neuropathies and myopathies that are characterized by intermediate filament-containing inclusions.
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Affiliation(s)
- Raymond Kwan
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan 48109-0622, USA.
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Alam H, Gangadaran P, Bhate AV, Chaukar DA, Sawant SS, Tiwari R, Bobade J, Kannan S, D'cruz AK, Kane S, Vaidya MM. Loss of keratin 8 phosphorylation leads to increased tumor progression and correlates with clinico-pathological parameters of OSCC patients. PLoS One 2011; 6:e27767. [PMID: 22114688 PMCID: PMC3219681 DOI: 10.1371/journal.pone.0027767] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 10/24/2011] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Keratins are cytoplasmic intermediate filament proteins expressed in tissue specific and differentiation dependent manner. Keratins 8 and 18 (K8 and K18) are predominantly expressed in simple epithelial tissues and perform both mechanical and regulatory functions. Aberrant expression of K8 and K18 is associated with neoplastic progression, invasion and poor prognosis in human oral squamous cell carcinomas (OSCCs). K8 and K18 undergo several post-translational modifications including phosphorylation, which are known to regulate their functions in various cellular processes. Although, K8 and K18 phosphorylation is known to regulate cell cycle, cell growth and apoptosis, its significance in cell migration and/or neoplastic progression is largely unknown. In the present study we have investigated the role of K8 phosphorylation in cell migration and/or neoplastic progression in OSCC. METHODOLOGY AND PRINCIPAL FINDINGS To understand the role of K8 phosphorylation in neoplastic progression of OSCC, shRNA-resistant K8 phospho-mutants of Ser73 and Ser431 were overexpressed in K8-knockdown human AW13516 cells (derived from SCC of tongue; generated previously). Wound healing assays and tumor growth in NOD-SCID mice were performed to analyze the cell motility and tumorigenicity respectively in overexpressed clones. The overexpressed K8 phospho-mutants clones showed significant increase in cell migration and tumorigenicity as compared with K8 wild type clones. Furthermore, loss of K8 Ser73 and Ser431 phosphorylation was also observed in human OSCC tissues analyzed by immunohistochemistry, where their dephosphorylation significantly correlated with size, lymph node metastasis and stage of the tumor. CONCLUSION AND SIGNIFICANCE Our results provide first evidence of a potential role of K8 phosphorylation in cell migration and/or tumorigenicity in OSCC. Moreover, correlation studies of K8 dephosphorylation with clinico-pathological parameters of OSCC patients also suggest its possible use in prognostication of human OSCC.
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Affiliation(s)
- Hunain Alam
- Cancer Research Institute (CRI), Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre (TMC), Kharghar, Navi Mumbai, India
| | - Prakash Gangadaran
- Cancer Research Institute (CRI), Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre (TMC), Kharghar, Navi Mumbai, India
| | - Amruta V. Bhate
- Cancer Research Institute (CRI), Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre (TMC), Kharghar, Navi Mumbai, India
| | - Devendra A. Chaukar
- Surgical Oncology, Head and Neck Unit, Tata Memorial Hospital (TMH), Parel, Mumbai, India
| | - Sharada S. Sawant
- Cancer Research Institute (CRI), Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre (TMC), Kharghar, Navi Mumbai, India
- Surgical Oncology, Head and Neck Unit, Tata Memorial Hospital (TMH), Parel, Mumbai, India
- Epidemiology and Clinical Trials Unit, Clinical Research Centre (CRC), Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre (TMC), Kharghar, Navi Mumbai, India
- Department of Pathology, Tata Memorial Hospital (TMH), Parel, Mumbai, India
| | - Richa Tiwari
- Cancer Research Institute (CRI), Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre (TMC), Kharghar, Navi Mumbai, India
| | - Jyoti Bobade
- Cancer Research Institute (CRI), Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre (TMC), Kharghar, Navi Mumbai, India
| | - Sadhana Kannan
- Epidemiology and Clinical Trials Unit, Clinical Research Centre (CRC), Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre (TMC), Kharghar, Navi Mumbai, India
| | - Anil K. D'cruz
- Surgical Oncology, Head and Neck Unit, Tata Memorial Hospital (TMH), Parel, Mumbai, India
| | - Shubhada Kane
- Department of Pathology, Tata Memorial Hospital (TMH), Parel, Mumbai, India
| | - Milind M. Vaidya
- Cancer Research Institute (CRI), Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre (TMC), Kharghar, Navi Mumbai, India
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30
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Pan X, Kane LA, Van Eyk JE, Coulombe PA. Type I keratin 17 protein is phosphorylated on serine 44 by p90 ribosomal protein S6 kinase 1 (RSK1) in a growth- and stress-dependent fashion. J Biol Chem 2011; 286:42403-42413. [PMID: 22006917 DOI: 10.1074/jbc.m111.302042] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Keratin 17 (K17) is a type I intermediate filament protein that is constitutively expressed in ectoderm-derived epithelial appendages and robustly induced in epidermis following injury, during inflammation, and in chronic diseases such as psoriasis and cancer. Mutations within K17 are responsible for two rare diseases related to ectodermal dysplasias. Studies in K17-null mice uncovered several roles for K17, including structural support, resistance to TNFα-induced apoptosis, regulation of protein synthesis, and modulation of cytokine expression. Yet, little is known about the regulation of K17 protein via post-translational modification. Here, we report that serine 44 in the N-terminal head domain of K17 (K17-Ser(44)) is phosphorylated in response to extracellular stimuli (serum, EGF, and the phorbol ester 12-O-tetradecanoylphorbol-13-acetate) that alter skin keratinocyte growth, and to cellular stresses (sorbitol-induced hyperosmotic shock, UV irradiation, and hydrogen peroxide-induced oxidative stress). It also occurs in basaloid skin tumors in situ. Upon its stimulation in skin keratinocytes, K17-Ser(44) phosphorylation is induced rapidly but stays on transiently. The majority of the phosphorylated K17-Ser(44) pool is polymer-bound and is not obviously related to a change in filament organization. The amino acid sequence surrounding K17-Ser(44) matches the consensus for the AGC family of basophilic kinases. We show that p90 RSK1, an AGC kinase involved in the regulation of cell survival and proliferation, phosphorylates K17-Ser(44) in skin keratinocytes. These findings confirm and expand the tight link that has emerged between K17 up-regulation and growth and stress responses in the skin epithelium.
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Affiliation(s)
- Xiaoou Pan
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205
| | - Lesley A Kane
- Department of Biological Chemistry, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205; Johns Hopkins Bayview Proteomic Center, Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, Maryland 21205
| | - Jennifer E Van Eyk
- Department of Biological Chemistry, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205; Johns Hopkins Bayview Proteomic Center, Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, Maryland 21205
| | - Pierre A Coulombe
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205; Department of Biological Chemistry, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205; Department of Dermatology, School of Medicine, Johns Hopkins University, Baltimore, Maryland 21205.
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31
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Abstract
Keratins are the intermediate filament (IF)-forming proteins of epithelial cells. Since their initial characterization almost 30 years ago, the total number of mammalian keratins has increased to 54, including 28 type I and 26 type II keratins. Keratins are obligate heteropolymers and, similarly to other IFs, they contain a dimeric central α-helical rod domain that is flanked by non-helical head and tail domains. The 10-nm keratin filaments participate in the formation of a proteinaceous structural framework within the cellular cytoplasm and, as such, serve an important role in epithelial cell protection from mechanical and non-mechanical stressors, a property extensively substantiated by the discovery of human keratin mutations predisposing to tissue-specific injury and by studies in keratin knockout and transgenic mice. More recently, keratins have also been recognized as regulators of other cellular properties and functions, including apico-basal polarization, motility, cell size, protein synthesis and membrane traffic and signaling. In cancer, keratins are extensively used as diagnostic tumor markers, as epithelial malignancies largely maintain the specific keratin patterns associated with their respective cells of origin, and, in many occasions, full-length or cleaved keratin expression (or lack there of) in tumors and/or peripheral blood carries prognostic significance for cancer patients. Quite intriguingly, several studies have provided evidence for active keratin involvement in cancer cell invasion and metastasis, as well as in treatment responsiveness, and have set the foundation for further exploration of the role of keratins as multifunctional regulators of epithelial tumorigenesis.
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Affiliation(s)
- V Karantza
- Department of Medicine, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, NJ, USA.
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32
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Menon MB, Schwermann J, Singh AK, Franz-Wachtel M, Pabst O, Seidler U, Omary MB, Kotlyarov A, Gaestel M. p38 MAP kinase and MAPKAP kinases MK2/3 cooperatively phosphorylate epithelial keratins. J Biol Chem 2010; 285:33242-33251. [PMID: 20724476 DOI: 10.1074/jbc.m110.132357] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The MAPK-activated protein kinases (MAPKAP kinases) MK2 and MK3 are directly activated via p38 MAPK phosphorylation, stabilize p38 by complex formation, and contribute to the stress response. The list of substrates of MK2/3 is increasing steadily. We applied a phosphoproteomics approach to compare protein phosphorylation in MK2/3-deficient cells rescued or not by ectopic expression of MK2. In addition to differences in phosphorylation of the known substrates of MK2, HSPB1 and Bag-2, we identified strong differences in phosphorylation of keratin 8 (K8). The phosphorylation of K8-Ser(73) is catalyzed directly by p38, which in turn shows MK2-dependent expression. Notably, analysis of small molecule p38 inhibitors on K8-Ser(73) phosphorylation also demonstrated reduced phosphorylations of keratins K18-Ser(52) and K20-Ser(13) but not of K8-Ser(431) or K18-Ser(33). Interestingly, K18-Ser(52) and K20-Ser(13) are not directly phosphorylated by p38 in vitro, but by MK2. Furthermore, anisomycin-stimulated phosphorylations of K20-Ser(13) and K18-Ser(52) are inhibited by small molecule inhibitors of both p38 and MK2. MK2 knockdown in HT29 cells leads to reduced K20-Ser(13) phosphorylation, which further supports the notion that MK2 is responsible for K20 phosphorylation in vivo. Physiologic relevance of these findings was confirmed by differences of K20-Ser(13) phosphorylation between the ileum of wild-type and MK2/3-deficient mice and by demonstrating p38- and MK2-dependent mucin secretion of HT29 cells. Therefore, MK2 and p38 MAPK function in concert to phosphorylate K8, K18, and K20 in intestinal epithelia.
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Affiliation(s)
- Manoj B Menon
- From the Institute of Biochemistry, Hannover 30625, Germany
| | | | - Anurag Kumar Singh
- Department of Gastroenterology, Hepatology, and Endocrinology, Hannover 30625, Germany
| | - Mirita Franz-Wachtel
- Proteome Center Tübingen, Interfaculty Institute for Cell Biology, University of Tübingen, Tübingen 72076, Germany
| | - Oliver Pabst
- Institute of Immunology, Medical School Hannover, Hannover 30625, Germany
| | - Ursula Seidler
- Department of Gastroenterology, Hepatology, and Endocrinology, Hannover 30625, Germany
| | - M Bishr Omary
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan 48109
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33
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McIntosh PB, Laskey P, Sullivan K, Davy C, Wang Q, Jackson DJ, Griffin HM, Doorbar J. E1--E4-mediated keratin phosphorylation and ubiquitylation: a mechanism for keratin depletion in HPV16-infected epithelium. J Cell Sci 2010; 123:2810-22. [PMID: 20663917 DOI: 10.1242/jcs.061978] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The keratin IF network of epidermal keratinocytes provides a protective barrier against mechanical insult, it is also a major player in absorbing stress in these cells. The human papilloma virus (HPV) type 16 E1--E4 protein accumulates in the upper layers of HPV16-infected epithelium and is known to associate with and reorganise the keratin IF network in cells in culture. Here, we show that this function is conserved amongst a number of HPV alpha-group E1--E4 proteins and that the differentiation-dependent keratins are also targeted. Using time-lapse microscopy, HPV16 E1--E4 was found to effect a dramatic cessation of keratin IF network dynamics by associating with both soluble and insoluble keratin. Network disruption was accompanied by keratin hyperphosphorylation at several sites, including K8 S73, which is typically phosphorylated in response to stress stimuli. Keratin immunoprecipitated from E1--E4-expressing cells was also found to be ubiquitylated, indicating that it is targeted for proteasomal degradation. Interestingly, the accumulation of hyperphosphorylated, ubiquitylated E1--E4-keratin structures was found to result in an impairment of proteasomal function. These observations shed new light on the mechanism of keratin IF network reorganisation mediated by HPV16 E1--E4 and provide an insight into the depletion of keratin co-incident with E1--E4 accumulation observed in HPV-infected epithelium.
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Affiliation(s)
- Pauline B McIntosh
- MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, N10 3UE, UK
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34
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Bertrand-Vallery V, Belot N, Dieu M, Delaive E, Ninane N, Demazy C, Raes M, Salmon M, Poumay Y, Debacq-Chainiaux F, Toussaint O. Proteomic profiling of human keratinocytes undergoing UVB-induced alternative differentiation reveals TRIpartite Motif Protein 29 as a survival factor. PLoS One 2010; 5:e10462. [PMID: 20454669 PMCID: PMC2862717 DOI: 10.1371/journal.pone.0010462] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Accepted: 04/06/2010] [Indexed: 02/01/2023] Open
Abstract
Background Repeated exposures to UVB of human keratinocytes lacking functional p16INK-4a and able to differentiate induce an alternative state of differentiation rather than stress-induced premature senescence. Methodology/Principal Findings A 2D-DIGE proteomic profiling of this alternative state of differentiation was performed herein at various times after the exposures to UVB. Sixty-nine differentially abundant protein species were identified by mass spectrometry, many of which are involved in keratinocyte differentiation and survival. Among these protein species was TRIpartite Motif Protein 29 (TRIM29). Increased abundance of TRIM29 following UVB exposures was validated by Western blot using specific antibody and was also further analysed by immunochemistry and by RT-PCR. TRIM29 was found very abundant in keratinocytes and reconstructed epidermis. Knocking down the expression of TRIM29 by short-hairpin RNA interference decreased the viability of keratinocytes after UVB exposure. The abundance of involucrin mRNA, a marker of late differentiation, increased concomitantly. In TRIM29-knocked down reconstructed epidermis, the presence of picnotic cells revealed cell injury. Increased abundance of TRIM29 was also observed upon exposure to DNA damaging agents and PKC activation. The UVB-induced increase of TRIM29 abundance was dependent on a PKC signaling pathway, likely PKCδ. Conclusions/Significance These findings suggest that TRIM29 allows keratinocytes to enter a protective alternative differentiation process rather than die massively after stress.
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Affiliation(s)
| | | | - Marc Dieu
- Research Unit of Cellular Biology, University of Namur (FUNDP), Namur, Belgium
| | - Edouard Delaive
- Research Unit of Cellular Biology, University of Namur (FUNDP), Namur, Belgium
| | - Noëlle Ninane
- Research Unit of Cellular Biology, University of Namur (FUNDP), Namur, Belgium
| | - Catherine Demazy
- Research Unit of Cellular Biology, University of Namur (FUNDP), Namur, Belgium
| | - Martine Raes
- Research Unit of Cellular Biology, University of Namur (FUNDP), Namur, Belgium
| | | | - Yves Poumay
- Cell and Tissue Laboratory, URPHYM, University of Namur (FUNDP), Namur, Belgium
| | | | - Olivier Toussaint
- Research Unit of Cellular Biology, University of Namur (FUNDP), Namur, Belgium
- * E-mail:
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35
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Abstract
Neurofilaments assemble from three intermediate-filament proteins, contribute to the radial growth of axons, and are exceptionally stable. Microtubules are dynamic structures that assemble from tubulin dimers to support intracellular transport of molecules and organelles. We show here that neurofilaments, and other intermediate-filament proteins, contain motifs in their N-terminal domains that bind unassembled tubulin. Peptides containing such motifs inhibit the in vitro polymerization of microtubules and can be taken up by cultured cells in which they disrupt microtubules leading to altered cell shapes and an arrest of division. In transgenic mice in which neurofilaments are withheld from the axonal compartment, axonal tubulin accumulation is normal but microtubules assemble in excessive numbers. These observations suggest a model in which axonal neurofilaments modulate local microtubule assembly. This capacity also suggests novel mechanisms through which inherited or acquired disruptions in intermediate filaments might contribute to pathogenesis in multiple conditions.
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36
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Lee CH, Coulombe PA. Self-organization of keratin intermediate filaments into cross-linked networks. ACTA ACUST UNITED AC 2009; 186:409-21. [PMID: 19651890 PMCID: PMC2728393 DOI: 10.1083/jcb.200810196] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Keratins, the largest subgroup of intermediate filament (IF) proteins, form a network of 10-nm filaments built from type I/II heterodimers in epithelial cells. A major function of keratin IFs is to protect epithelial cells from mechanical stress. Like filamentous actin, keratin IFs must be cross-linked in vitro to achieve the high level of mechanical resilience characteristic of live cells. Keratins 5 and 14 (K5 and K14), the main pairing occurring in the basal progenitor layer of epidermis and related epithelia, can readily self-organize into large filament bundles in vitro and in vivo. Here, we show that filament self-organization is mediated by multivalent interactions involving distinct regions in K5 and K14 proteins. Self-organization is determined independently of polymerization into 10-nm filaments, but involves specific type I–type II keratin complementarity. We propose that self-organization is a key determinant of the structural support function of keratin IFs in vivo.
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Affiliation(s)
- Chang-Hun Lee
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
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37
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Eriksson JE, Dechat T, Grin B, Helfand B, Mendez M, Pallari HM, Goldman RD. Introducing intermediate filaments: from discovery to disease. J Clin Invest 2009; 119:1763-71. [PMID: 19587451 DOI: 10.1172/jci38339] [Citation(s) in RCA: 308] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
It took more than 100 years before it was established that the proteins that form intermediate filaments (IFs) comprise a unified protein family, the members of which are ubiquitous in virtually all differentiated cells and present both in the cytoplasm and in the nucleus. However, during the past 2 decades, knowledge regarding the functions of these structures has been expanding rapidly. Many disease-related roles of IFs have been revealed. In some cases, the molecular mechanisms underlying these diseases reflect disturbances in the functions traditionally assigned to IFs, i.e., maintenance of structural and mechanical integrity of cells and tissues. However, many disease conditions seem to link to the nonmechanical functions of IFs, many of which have been defined only in the past few years.
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Affiliation(s)
- John E Eriksson
- Department of Biology, Abo Akademi University, Turku, Finland.
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38
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Kostan J, Gregor M, Walko G, Wiche G. Plectin isoform-dependent regulation of keratin-integrin alpha6beta4 anchorage via Ca2+/calmodulin. J Biol Chem 2009; 284:18525-36. [PMID: 19419971 DOI: 10.1074/jbc.m109.008474] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The detachment of epithelial cells from the basal matrix during wound healing and differentiation of keratinocytes requires the disassembly of the hemidesmosomal multiprotein adhesion complex. Integrin alpha6beta4-plectin interaction plays a major role in the formation of hemidesmosomes, and thus the mechanisms regulating this interaction should be critical also for the disassembly process. Here we show that a particular plectin isoform (1a) interacts with the Ca(2+)-sensing protein calmodulin in a Ca(2+)-dependent manner. As a result of this interaction, binding of the hemidesmosome-associated plectin isoform 1a to integrin beta4 is substantially diminished. Calmodulin-binding inhibits also the interaction of plectin with F-actin. Further, we found that, during Ca(2+)-induced keratinocyte differentiation, plectin 1a is first relocated within the cell and later down-regulated, suggesting that Ca(2+) affects the fate of plectin 1a upon its release from hemidesmosomes. We propose a novel model for the disassembly of hemidesmosomes during keratinocyte differentiation, where both, binding of calmodulin to plectin 1a and phosphorylation of integrin beta4 by protein kinases, are required for disruption of the integrin alpha6beta4-plectin complex.
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Affiliation(s)
- Julius Kostan
- Department of Molecular Cell Biology, Max F. Perutz Laboratories, University of Vienna, Vienna A-1030, Austria
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39
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Berkowitz P, Chua M, Liu Z, Diaz LA, Rubenstein DS. Autoantibodies in the autoimmune disease pemphigus foliaceus induce blistering via p38 mitogen-activated protein kinase-dependent signaling in the skin. THE AMERICAN JOURNAL OF PATHOLOGY 2008; 173:1628-36. [PMID: 18988808 DOI: 10.2353/ajpath.2008.080391] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Pemphigus foliaceus (PF) is a human autoimmune blistering disease in which a humoral immune response targeting the skin results in a loss of keratinocyte cell-cell adhesion in the superficial layers of the epidermal epithelium. In PF, desmoglein-1-specific autoantibodies induce blistering. Evidence is beginning to accumulate that activation of signaling may have an important role in the ability of pathogenic pemphigus IgGs to induce blistering and that both p38 mitogen-activated protein kinase (MAPK) and heat shock protein (HSP) 27 are part of this signaling pathway. This study was undertaken to investigate the ability of PF IgGs to activate signaling as well as the contribution of this signaling pathway to blister induction in an in vivo model of PF. Phosphorylation of both p38 MAPK and HSP25, the murine HSP27 homolog, was observed in the skin of PF IgG-treated mice. Furthermore, inhibition of p38 MAPK blocked the ability of PF IgGs to induce blistering in vivo. These results indicate that PF IgG-induced blistering is dependent on activation of p38 MAPK in the target keratinocyte. Rather than influencing the immune system, limiting the autoantibody-induced intracellular signaling response that leads to target end-organ damage may be a more viable therapeutic strategy for the treatment of autoimmune diseases. Inhibition of p38 MAPK may be an effective strategy for the treatment of PF.
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Affiliation(s)
- Paula Berkowitz
- Department of Dermatology, The University of North Carolina School of Medicine, Chapel Hill, NC 27599-7287, USA
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40
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Felder E, Siebenbrunner M, Busch T, Fois G, Miklavc P, Walther P, Dietl P. Mechanical strain of alveolar type II cells in culture: changes in the transcellular cytokeratin network and adaptations. Am J Physiol Lung Cell Mol Physiol 2008; 295:L849-57. [PMID: 18708634 DOI: 10.1152/ajplung.00503.2007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Mechanical forces exert multiple effects in cells, ranging from altered protein expression patterns to cell damage and death. Despite undisputable biological importance, little is known about structural changes in cells subjected to strain ex vivo. Here, we undertake the first transmission electron microscopy investigation combined with fluorescence imaging on pulmonary alveolar type II cells that are subjected to equibiaxial strain. When cells are investigated immediately after stretch, we demonstrate that curved cytokeratin (CK) fibers are straightened out at 10% increase in cell surface area (CSA) and that this is accompanied by a widened extracellular gap of desmosomes-the insertion points of CK fibers. Surprisingly, a CSA increase by 20% led to higher fiber curvatures of CK fibers and a concurrent return of the desmosomal gap to normal values. Since 20% CSA increase also induced a significant phosphorylation of CK8-ser431, we suggest CK phosphorylation might lower the tensile force of the transcellular CK network, which could explain the morphological observations. Stretch durations of 5 min caused membrane injury in up to 24% of the cells stretched by 30%, but the CK network remained surprisingly intact even in dead cells. We conclude that CK and desmosomes constitute a strong transcellular scaffold that survives cell death and hypothesize that phosphorylation of CK fibers is a mechano-induced adaptive mechanism to maintain epithelial overall integrity.
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Affiliation(s)
- Edward Felder
- Institute for General Physiology/M-25, University of Ulm, Albert Einstein Allee 11, 89081 Ulm, Germany.
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41
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Hyder CL, Pallari HM, Kochin V, Eriksson JE. Providing cellular signposts - Post-translational modifications of intermediate filaments. FEBS Lett 2008; 582:2140-8. [DOI: 10.1016/j.febslet.2008.04.064] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2008] [Revised: 04/29/2008] [Accepted: 04/30/2008] [Indexed: 10/22/2022]
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42
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Liovic M, Lee B, Tomic-Canic M, D'Alessandro M, Bolshakov VN, Lane EB. Dual-specificity phosphatases in the hypo-osmotic stress response of keratin-defective epithelial cell lines. Exp Cell Res 2008; 314:2066-75. [PMID: 18410923 DOI: 10.1016/j.yexcr.2008.02.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Revised: 02/24/2008] [Accepted: 02/26/2008] [Indexed: 01/31/2023]
Abstract
Although mutations in intermediate filament proteins cause many human disorders, the detailed pathogenic mechanisms and the way these mutations affect cell metabolism are unclear. In this study, selected keratin mutations were analysed for their effect on the epidermal stress response. Expression profiles of two keratin-mutant cell lines from epidermolysis bullosa simplex patients (one severe and one mild) were compared to a control keratinocyte line before and after challenge with hypo-osmotic shock, a common physiological stress that transiently distorts cell shape. Fewer changes in gene expression were found in cells with the severely disruptive mutation (55 genes altered) than with the mild mutation (174 genes) or the wild type cells (261 genes) possibly due to stress response pre-activation in these cells. We identified 16 immediate-early genes contributing to a general cell response to hypo-osmotic shock, and 20 genes with an altered expression pattern in the mutant keratin lines only. A number of dual-specificity phosphatases (MKP-1, MKP-2, MKP-3, MKP-5 and hVH3) are differentially regulated in these cells, and their downstream targets p-ERK and p-p38 are significantly up-regulated in the mutant keratin lines. Our findings strengthen the case for the expression of mutant keratin proteins inducing physiological stress, and this intrinsic stress may affect the cell responses to secondary stresses in patients' skin.
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Affiliation(s)
- Mirjana Liovic
- National Institute of Chemistry, Ljubljana, Slovenia; CRUK Cell Structure Research Group, University of Dundee College of Life Sciences, MSI/WTB Complex, Dundee, UK.
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Spazierer D, Raberger J, Gross K, Fuchs P, Wiche G. Stress-induced recruitment of epiplakin to keratin networks increases their resistance to hyperphosphorylation-induced disruption. J Cell Sci 2008; 121:825-33. [PMID: 18285451 DOI: 10.1242/jcs.013755] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Epiplakin is a large (>725 kDa) cytoskeletal protein exclusively expressed in epithelial tissues. It has a unique structure, consisting entirely of plakin repeat domains (PRDs), one of the hallmarks of spectraplakin protein family members. Previous studies, including the phenotypic analyses of knockout mice, failed to reveal the biological function of epiplakin. Using in vitro binding assays, we show here that all but one of the 16 PRDs of mouse epiplakin bind to keratins of basal keratinocytes. Nevertheless, in primary keratinocyte cell cultures, epiplakin only partially colocalized with keratin intermediate filament networks. However, upon application of cellular stress in the form of keratin hyperphosphorylation, osmotic shock or UV irradiation, the entire cytoplasmic epiplakin pool became associated with keratin. In response to such types of stress, epiplakin initially translocated to the still-intact keratin filament network and remained associated with keratin after its disruption and transformation into granular aggregates. Time-course experiments revealed that serine/threonine (okadaic acid) and tyrosine (orthovanadate) phosphatase inhibitor-induced filament disruption in differentiated keratinocytes proceeded faster in epiplakin-deficient cells compared with wild-type cells. Our data suggest that epiplakin plays a role in keratin filament reorganization in response to stress, probably by protecting keratin filaments against disruption in a chaperone-like fashion.
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Affiliation(s)
- Daniel Spazierer
- Department of Molecular Cell Biology, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
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Chernyavsky AI, Arredondo J, Vetter DE, Grando SA. Central role of alpha9 acetylcholine receptor in coordinating keratinocyte adhesion and motility at the initiation of epithelialization. Exp Cell Res 2007; 313:3542-55. [PMID: 17706194 PMCID: PMC2682983 DOI: 10.1016/j.yexcr.2007.07.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2007] [Revised: 07/13/2007] [Accepted: 07/13/2007] [Indexed: 11/24/2022]
Abstract
Epithelialization, a major component of wound healing, depends on keratinocyte adhesion and migration. Initiation of migration relies upon the ability of keratinocytes to free themselves from neighboring cells and basement membrane. The local cytotransmitter acetylcholine (ACh) controls keratinocyte adhesion and locomotion through different classes of ACh receptors (AChR). In this study, we explored signaling pathways downstream of the alpha9 AChR subtype that had been shown to control cell shape and cytoplasm mobility. Inactivation of alpha9 signaling by pharmacologic antagonism and RNA interference in keratinocyte cultures and null mutation in knockout mice delayed wound re-epithelialization in vitro and in vivo, respectively, and diminished the extent of colony scattering and cell outgrowth from the megacolony. Although keratinocytes at the leading edge elongated, produced filopodia and moved out, most of them remained anchored to the substrate by long cytoplasmic processes that stretched during their migration instead of retracting the uropod. Since the velocity of keratinocyte migration was not altered, we investigated the role of alpha9 in assembly/disassembly of the cell-cell and cell-matrix adhesion complexes. Stimulation of alpha9 upregulated in a time-dependent fashion phosphorylation of the adhesion molecules comprising focal adhesions (FAK, paxillin) and intercellular junctions (beta-catenin, desmoglein 3) as well as cytokeratins. Stimulation of alpha9 was associated with activation of phospholipase C, Src, EGF receptor kinase, protein kinase C, Rac and Rho, whereas inhibition of this receptor interfered with phosphorylation of adhesion and cytoskeletal proteins, and also altered cell-cell cohesion. We conclude that signaling through alpha9 AChR is critical for completion of the very early stages of epithelialization. By activating alpha9 AChR, ACh can control the dynamics and strength of cell-cell cohesion, disabling of a trailing uropod and disassembly and reassembly of focal adhesions, thus facilitating crawling locomotion.
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Affiliation(s)
- Alex I Chernyavsky
- Department of Dermatology, University of California Irvine, C340 Medical Sciences I, Irvine, CA 92697, USA
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Wöll S, Windoffer R, Leube RE. p38 MAPK-dependent shaping of the keratin cytoskeleton in cultured cells. ACTA ACUST UNITED AC 2007; 177:795-807. [PMID: 17535969 PMCID: PMC2064280 DOI: 10.1083/jcb.200703174] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Plasticity of the resilient keratin intermediate filament cytoskeleton is an important prerequisite for epithelial tissue homeostasis. Here, the contribution of stress-activated p38 MAPK to keratin network organization was examined in cultured cells. It was observed that phosphorylated p38 colocalized with keratin granules that were rapidly formed in response to orthovanadate. The same p38p recruitment was noted during mitosis, in various stress situations and in cells producing mutant keratins. In all these situations keratin 8 became phosphorylated on S73, a well-known p38 target site. To demonstrate that p38-dependent keratin phosphorylation determines keratin organization, p38 activity was pharmacologically and genetically modulated: up-regulation induced keratin granule formation, whereas down-regulation prevented keratin filament network disassembly. Furthermore, transient p38 inhibition also inhibited keratin filament precursor formation and mutant keratin granule dissolution. Collectively, the rapid and reversible effects of p38 activity on keratin phosphorylation and organization in diverse physiological, stress, and pathological situations identify p38-dependent signalling as a major intermediate filament–regulating pathway.
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Affiliation(s)
- Stefan Wöll
- Department of Anatomy and Cell Biology, Johannes Gutenberg University, 55128 Mainz, Germany
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Ostrowski J, Mikula M, Karczmarski J, Rubel T, Wyrwicz LS, Bragoszewski P, Gaj P, Dadlez M, Butruk E, Regula J. Molecular defense mechanisms of Barrett's metaplasia estimated by an integrative genomics. J Mol Med (Berl) 2007; 85:733-43. [PMID: 17415542 DOI: 10.1007/s00109-007-0176-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2006] [Revised: 01/11/2007] [Accepted: 01/30/2007] [Indexed: 12/18/2022]
Abstract
Barrett's esophagus is characterized by the replacement of squamous epithelium with specialized intestinal metaplastic mucosa. The exact mechanisms of initiation and development of Barrett's metaplasia remain unknown, but a hypothesis of "successful adaptation" against noxious reflux components has been proposed. To search for the repertoire of adaptation mechanisms of Barrett's metaplasia, we employed high-throughput functional genomic and proteomic methods that defined the molecular background of metaplastic mucosa resistance to reflux. Transcriptional profiling was established for 23 pairs of esophageal squamous epithelium and Barrett's metaplasia tissue samples using Affymetrix U133A 2.0 GeneChips and validated by quantitative real-time polymerase chain reaction. Differences in protein composition were assessed by electrophoretic and mass-spectrometry-based methods. Among 2,822 genes differentially expressed between Barrett's metaplasia and squamous epithelium, we observed significantly overexpressed metaplastic mucosa genes that encode cytokines and growth factors, constituents of extracellular matrix, basement membrane and tight junctions, and proteins involved in prostaglandin and phosphoinositol metabolism, nitric oxide production, and bioenergetics. Their expression likely reflects defense and repair responses of metaplastic mucosa, whereas overexpression of genes encoding heat shock proteins and several protein kinases in squamous epithelium may reflect lower resistance of normal esophageal epithelium than Barrett's metaplasia to reflux components. Despite the methodological and interpretative difficulties in data analyses discussed in this paper, our studies confirm that Barrett's metaplasia may be regarded as a specific microevolution allowing for accumulation of mucosal morphological and physiological changes that better protect against reflux injury.
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Affiliation(s)
- Jerzy Ostrowski
- Department of Gastroenterology, Medical Center for Postgraduate Education, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, ul. Roentgena 5, 02-781, Warsaw, Poland.
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Magin TM, Vijayaraj P, Leube RE. Structural and regulatory functions of keratins. Exp Cell Res 2007; 313:2021-32. [PMID: 17434482 DOI: 10.1016/j.yexcr.2007.03.005] [Citation(s) in RCA: 201] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2007] [Revised: 03/02/2007] [Accepted: 03/06/2007] [Indexed: 12/11/2022]
Abstract
The diversity of epithelial functions is reflected by the expression of distinct keratin pairs that are responsible to protect epithelial cells against mechanical stress and to act as signaling platforms. The keratin cytoskeleton integrates these functions by forming a supracellular scaffold that connects at desmosomal cell-cell adhesions. Multiple human diseases and murine knockouts in which the integrity of this system is destroyed testify to its importance as a mechanical stabilizer in certain epithelia. Yet, surprisingly little is known about the precise mechanisms responsible for assembly and disease pathology. In addition to these structural aspects of keratin function, experimental evidence accumulating in recent years has led to a much more complex view of the keratin cytoskeleton. Distinct keratins emerge as highly dynamic scaffolds in different settings and contribute to cell size determination, translation control, proliferation, cell type-specific organelle transport, malignant transformation and various stress responses. All of these properties are controlled by highly complex patterns of phosphorylation and molecular associations.
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Affiliation(s)
- Thomas M Magin
- Institute for Physiological Chemistry, Division of Cell Biochemistry, Bonner Forum Biomedizin and LIMES, Universität Bonn, Nussallee 11, 53115 Bonn, Germany.
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Abstract
Intermediate filaments (IFs) are cytoskeletal structures that are crucial for maintaining the structural and mechanical integrity of cells and tissues. Intriguingly, a wide range of previously unknown nonmechanical roles for the IF cytoskeleton are emerging: Recent studies have linked IFs to the integration of signals related to the determination of cell size, the regulation of cell migration and cell survival, and the buffering of the effects of stress-activated kinases. The characteristic structural features and expression patterns of the different members of this diverse family of highly abundant proteins make them well suited to act as cell- and tissue-specific modifiers and organizers of signaling.
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Affiliation(s)
- Hanna-Mari Pallari
- Turku Centre for Biotechnology, University of Turku and Abo Akademi University, Post Office Box 123, FIN- 20521 Turku, Finland
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Osmanagic-Myers S, Gregor M, Walko G, Burgstaller G, Reipert S, Wiche G. Plectin-controlled keratin cytoarchitecture affects MAP kinases involved in cellular stress response and migration. ACTA ACUST UNITED AC 2006; 174:557-68. [PMID: 16908671 PMCID: PMC2064261 DOI: 10.1083/jcb.200605172] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Plectin is a major intermediate filament (IF)-based cytolinker protein that stabilizes cells and tissues mechanically, regulates actin filament dynamics, and serves as a scaffolding platform for signaling molecules. In this study, we show that plectin deficiency is a cause of aberrant keratin cytoskeleton organization caused by a lack of orthogonal IF cross-linking. Keratin networks in plectin-deficient cells were more susceptible to osmotic shock-induced retraction from peripheral areas, and their okadaic acid-induced disruption (paralleled by stress-activated MAP kinase p38 activation) proceeded faster. Basal activities of the MAP kinase Erk1/2 and of the membrane-associated upstream protein kinases c-Src and PKCdelta were significantly elevated, and increased migration rates, as assessed by in vitro wound-closure assays and time-lapse microscopy, were observed. Forced expression of RACK1, which is the plectin-binding receptor protein for activated PKCdelta, in wild-type keratinocytes elevated their migration potential close to that of plectin-null cells. These data establish a link between cytolinker-controlled cytoarchitecture/scaffolding functions of keratin IFs and specific MAP kinase cascades mediating distinct cellular responses.
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Affiliation(s)
- Selma Osmanagic-Myers
- Department of Molecular Cell Biology, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
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Frankova J, Kubala L, Velebny V, Ciz M, Lojek A. The effect of hyaluronan combined with KI3 complex (Hyiodine wound dressing) on keratinocytes and immune cells. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2006; 17:891-8. [PMID: 16977386 DOI: 10.1007/s10856-006-0179-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2005] [Accepted: 10/24/2005] [Indexed: 05/11/2023]
Abstract
Hyiodine (high molecular weight hyaluronan combined with KI3 complex) is a new non-adhesive wound dressing which significantly improves the healing process. The aim of the study was to investigate the effects of Hyoidine on functional properties of isolated human keratinocytes and leukocytes, and on those of U937 and HL60 cell lines. While KI3 complex inhibited the viability and proliferation of the cells tested, Hyiodine did not have any significant effect. The expression of CD11b, CD62L and CD69 on PMNL, monocytes and lymphocytes, as well as the oxidative burst of blood neutrophils, were not changed. On the contrary, Hyiodine inhibited the PMA-activated oxidative burst and significantly increased the production of IL-6 and TNF-alpha by lymphocytes. It was concluded that hyaluronan content of Hyiodine reduces the toxic effect of KI3 complex on cells and speeds up the wound healing process by increasing the production of inflammatory cytokines.
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Affiliation(s)
- Jana Frankova
- CPN spol. s r o, Dolni Dobrouc 401, 562 01, Dolni Dobrouc, Czech Republic.
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