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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: 29] [Impact Index Per Article: 4.1] [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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Khan I, Maldonado E, Vasconcelos V, O'Brien SJ, Johnson WE, Antunes A. Mammalian keratin associated proteins (KRTAPs) subgenomes: disentangling hair diversity and adaptation to terrestrial and aquatic environments. BMC Genomics 2014; 15:779. [PMID: 25208914 PMCID: PMC4180150 DOI: 10.1186/1471-2164-15-779] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Accepted: 07/30/2014] [Indexed: 11/24/2022] Open
Abstract
Background Adaptation of mammals to terrestrial life was facilitated by the unique vertebrate trait of body hair, which occurs in a range of morphological patterns. Keratin associated proteins (KRTAPs), the major structural hair shaft proteins, are largely responsible for hair variation. Results We exhaustively characterized the KRTAP gene family in 22 mammalian genomes, confirming the existence of 30 KRTAP subfamilies evolving at different rates with varying degrees of diversification and homogenization. Within the two major classes of KRTAPs, the high cysteine (HS) subfamily experienced strong concerted evolution, high rates of gene conversion/recombination and high GC content. In contrast, high glycine-tyrosine (HGT) KRTAPs showed evidence of positive selection and low rates of gene conversion/recombination. Species with more hair and of higher complexity tended to have more KRATP genes (gene expansion). The sloth, with long and coarse hair, had the most KRTAP genes (175 with 141 being intact). By contrast, the “hairless” dolphin had 35 KRTAPs and the highest pseudogenization rate (74% relative to the 19% mammalian average). Unique hair-related phenotypes, such as scales (armadillo) and spines (hedgehog), were correlated with changes in KRTAPs. Gene expression variation probably also influences hair diversification patterns, for example human have an identical KRTAP repertoire as apes, but much less hair. Conclusions We hypothesize that differences in KRTAP gene repertoire and gene expression, together with distinct rates of gene conversion/recombination, pseudogenization and positive selection, are likely responsible for micro and macro-phenotypic hair diversification among mammals in response to adaptations to ecological pressures. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-779) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | - Agostinho Antunes
- CIMAR/CIIMAR, Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Rua dos Bragas 177, 4050-123 Porto, Portugal.
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3
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Kaushik G, Engler AJ. From stem cells to cardiomyocytes: the role of forces in cardiac maturation, aging, and disease. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 126:219-42. [PMID: 25081620 DOI: 10.1016/b978-0-12-394624-9.00009-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Stem cell differentiation into a variety of lineages is known to involve signaling from the extracellular niche, including from the physical properties of that environment. What regulates stem cell responses to these cues is there ability to activate different mechanotransductive pathways. Here, we will review the structures and pathways that regulate stem cell commitment to a cardiomyocyte lineage, specifically examining proteins within muscle sarcomeres, costameres, and intercalated discs. Proteins within these structures stretch, inducing a change in their phosphorylated state or in their localization to initiate different signals. We will also put these changes in the context of stem cell differentiation into cardiomyocytes, their subsequent formation of the chambered heart, and explore negative signaling that occurs during disease.
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Affiliation(s)
- Gaurav Kaushik
- Department of Bioengineering, University of California, San Diego, La Jolla, California, USA
| | - Adam J Engler
- Department of Bioengineering, University of California, San Diego, La Jolla, California, USA
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4
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Leitner A, Paust T, Marti O, Walther P, Herrmann H, Beil M. Properties of intermediate filament networks assembled from keratin 8 and 18 in the presence of Mg²+. Biophys J 2012; 103:195-201. [PMID: 22853896 PMCID: PMC3403007 DOI: 10.1016/j.bpj.2012.06.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 06/04/2012] [Accepted: 06/06/2012] [Indexed: 01/10/2023] Open
Abstract
The mechanical properties of epithelial cells are modulated by structural changes in keratin intermediate filament networks. To investigate the relationship between network architecture and viscoelasticity, we assembled keratin filaments from recombinant keratin proteins 8 (K8) and 18 (K18) in the presence of divalent ions (Mg(2+)). We probed the viscoelastic modulus of the network by tracking the movement of microspheres embedded in the network during assembly, and studied the network architecture using scanning electron microscopy. Addition of Mg(2+) at physiological concentrations (<1 mM) resulted in networks whose structure was similar to that of keratin networks in epithelial cells. Moreover, the elastic moduli of networks assembled in vitro were found to be within the same magnitude as those measured in keratin networks of detergent-extracted epithelial cells. These findings suggest that Mg(2+)-induced filament cross-linking represents a valid model for studying the cytoskeletal mechanics of keratin networks.
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Affiliation(s)
- Anke Leitner
- Institut für Experimentelle Physik, University of Ulm, Ulm, Germany
| | - Tobias Paust
- Institut für Experimentelle Physik, University of Ulm, Ulm, Germany
| | - Othmar Marti
- Institut für Experimentelle Physik, University of Ulm, Ulm, Germany
| | - Paul Walther
- Electron Microscopy Facility, University of Ulm, Ulm, Germany
| | - Harald Herrmann
- Division of Molecular Genetics, German Cancer Research Center, Heidelberg, Germany
| | - Michael Beil
- Department of Medicine I, University of Ulm, Ulm, Germany
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5
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Keratin gene mutations in disorders of human skin and its appendages. Arch Biochem Biophys 2010; 508:123-37. [PMID: 21176769 DOI: 10.1016/j.abb.2010.12.019] [Citation(s) in RCA: 134] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 12/16/2010] [Indexed: 11/21/2022]
Abstract
Keratins, the major structural protein of all epithelia are a diverse group of cytoskeletal scaffolding proteins that form intermediate filament networks, providing structural support to keratinocytes that maintain the integrity of the skin. Expression of keratin genes is usually regulated by differentiation of the epidermal cells within the stratifying squamous epithelium. Amongst the 54 known functional keratin genes in humans, about 22 different genes including, the cornea, hair and hair follicle-specific keratins have been implicated in a wide range of hereditary diseases. The exact phenotype of each disease usually reflects the spatial expression level and the types of mutated keratin genes, the location of the mutations and their consequences at sub-cellular levels as well as other epigenetic and/or environmental factors. The identification of specific pathogenic mutations in keratin disorders formed the basis of our understanding that led to re-classification, improved diagnosis with prognostic implications, prenatal testing and genetic counseling in severe keratin genodermatoses. Molecular defects in cutaneous keratin genes encoding for keratin intermediate filaments (KIFs) causes keratinocytes and tissue-specific fragility, accounting for a large number of genetic disorders in human skin and its appendages. These diseases are characterized by keratinocytes fragility (cytolysis), intra-epidermal blistering, hyperkeratosis, and keratin filament aggregation in severely affected tissues. Examples include epidermolysis bullosa simplex (EBS; K5, K14), keratinopathic ichthyosis (KPI; K1, K2, K10) i.e. epidermolytic ichthyosis (EI; K1, K10) and ichthyosis bullosa of Siemens (IBS; K2), pachyonychia congenita (PC; K6a, K6b, K16, K17), epidermolytic palmo-plantar keratoderma (EPPK; K9, (K1)), monilethrix (K81, K83, K86), ectodermal dysplasia (ED; K85) and steatocystoma multiplex. These keratins also have been identified to have roles in apoptosis, cell proliferation, wound healing, tissue polarity and remodeling. This review summarizes and discusses the clinical, ultrastructural, molecular genetics and biochemical characteristics of a broad spectrum of keratin-related genodermatoses, with special clinical emphasis on EBS, EI and PC. We also highlight current and emerging model tools for prognostic future therapies. Hopefully, disease modeling and in-depth understanding of the molecular pathogenesis of the diseases may lead to the development of novel therapies for several hereditary cutaneous diseases.
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7
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Minor J, Dunstan R, Guyon R, André C, Barnhart K, Credille K. Comparative sequence analysis and radiation hybrid mapping of the canine keratin 10 gene. ACTA ACUST UNITED AC 2006; 16:89-95. [PMID: 16147859 DOI: 10.1080/10425170500069932] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The type I keratin, K10, is expressed in epidermal keratinocytes undergoing terminal differentiation to form the stratum corneum, a barrier essential for life. In order to facilitate the study of keratinization disorders in the dog, the sequence and mapping of KRT10 is reported. The coding region of KRT10 is 1707 bp and is comprised of eight exons. Although the length of KRT10 has been reported to be polymorphic in humans, this was not observed in the eight domestic dog breeds studied, although one wild canid displayed a size difference. The structure and sequence of this gene is highly conserved across mammalian species. Canine K10 had an 86% amino acid identity with the human gene. KRT10 was localized to the on-going canine radiation hybrid map to chromosome 9 in the type I keratin gene cluster.
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Affiliation(s)
- J Minor
- Department of Pathobiology, Texas A&M University, College Station, TX 77843-4467, USA
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8
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Chang L, Shav-Tal Y, Trcek T, Singer RH, Goldman RD. Assembling an intermediate filament network by dynamic cotranslation. ACTA ACUST UNITED AC 2006; 172:747-58. [PMID: 16505169 PMCID: PMC2063706 DOI: 10.1083/jcb.200511033] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We have been able to observe the dynamic interactions between a specific messenger RNA (mRNA) and its protein product in vivo by studying the synthesis and assembly of peripherin intermediate filaments (IFs). The results show that peripherin mRNA-containing particles (messenger ribonucleoproteins [mRNPs]) move mainly along microtubules (MT). These mRNPs are translationally silent, initiating translation when they cease moving. Many peripherin mRNPs contain multiple mRNAs, possibly amplifying the total amount of protein synthesized within these "translation factories." This mRNA clustering is dependent on MT, regulatory sequences within the RNA and the nascent protein. Peripherin is cotranslationally assembled into insoluble, nonfilamentous particles that are precursors to the long IF that form extensive cytoskeletal networks. The results show that the motility and targeting of peripherin mRNPs, their translational control, and the assembly of an IF cytoskeletal system are linked together in a process we have termed dynamic cotranslation.
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Affiliation(s)
- Lynne Chang
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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9
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Er Rafik M, Doucet J, Briki F. The intermediate filament architecture as determined by X-ray diffraction modeling of hard alpha-keratin. Biophys J 2005; 86:3893-904. [PMID: 15189886 PMCID: PMC1304291 DOI: 10.1529/biophysj.103.034694] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Despite investigation since the 1950s, the molecular architecture of intermediate filaments has not yet been fully elucidated. Reliable information about the longitudinal organization of the molecules within the filaments and about the lateral interfilament packing is now available, which is not the case for the transverse architecture. Interesting results were recently obtained from in vitro microscopy observations and cross-linking of keratin, desmin, and vimentin analyses. The structural features that emerge from these analyses could not be fully representative of the in vivo architecture because intermediate filaments are subject to polymorphism. To bring new light to the transverse intermediate filament architecture, we have analyzed the x-ray scattering equatorial profile of human hair. Its comparison with simulated profiles from atomic models of a real sequence has allowed results to be obtained that are representative of hard alpha-keratin intermediate filaments under in vivo conditions. In short, the alpha-helical coiled coils, which are characteristic of the central rod of intermediate filament dimers, are straight and not supercoiled into oligomers; the radial density across the intermediate filament section is fairly uniform; the coiled coils are probably assembled into tetrameric oligomers, and finally the oligomer positions and orientations are not regularly ordered. These features are discussed in terms of filament self-assembling and structural variability.
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Affiliation(s)
- Meriem Er Rafik
- Laboratoire d'Utilisation du Rayonnement Electromagnetique, Centre Universitaire Paris-Sud, Orsay, France
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10
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Yoon KH, Yoon M, Moir RD, Khuon S, Flitney FW, Goldman RD. Insights into the dynamic properties of keratin intermediate filaments in living epithelial cells. J Cell Biol 2001; 153:503-16. [PMID: 11331302 PMCID: PMC2190576 DOI: 10.1083/jcb.153.3.503] [Citation(s) in RCA: 126] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2001] [Accepted: 03/07/2001] [Indexed: 11/22/2022] Open
Abstract
The properties of keratin intermediate filaments (IFs) have been studied after transfection with green fluorescent protein (GFP)-tagged K18 and/or K8 (type I/II IF proteins). GFP-K8 and -K18 become incorporated into tonofibrils, which are comprised of bundles of keratin IFs. These tonofibrils exhibit a remarkably wide range of motile and dynamic activities. Fluorescence recovery after photobleaching (FRAP) analyses show that they recover their fluorescence slowly with a recovery t(1/2) of approximately 100 min. The movements of bleach zones during recovery show that closely spaced tonofibrils (<1 microm apart) often move at different rates and in different directions. Individual tonofibrils frequently change their shapes, and in some cases these changes appear as propagated waveforms along their long axes. In addition, short fibrils, termed keratin squiggles, are seen at the cell periphery where they move mainly towards the cell center. The motile properties of keratin IFs are also compared with those of type III IFs (vimentin) in PtK2 cells. Intriguingly, the dynamic properties of keratin tonofibrils and squiggles are dramatically different from those of vimentin fibrils and squiggles within the same cytoplasmic regions. This suggests that there are different factors regulating the dynamic properties of different types of IFs within the same cytoplasmic regions.
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Affiliation(s)
- Kyeong Han Yoon
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611
- Department of Dermatology, Ajou University School of Medicine, Suwon 442-721, Korea
| | - Miri Yoon
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611
| | - Robert D. Moir
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611
| | - Satya Khuon
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611
| | - Frederick W. Flitney
- School of Biology, University of St. Andrews, St. Andrews KY16 9TS, Scotland, United Kingdom
| | - Robert D. Goldman
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611
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11
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Bawden CS, Powell BC, Walker SK, Rogers GE. Expression of a wool intermediate filament keratin transgene in sheep fibre alters structure. Transgenic Res 1998; 7:273-87. [PMID: 9859216 DOI: 10.1023/a:1008830314386] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Alteration of the protein composition of the wool fibre via transgenesis with sheep wool keratin and keratin associated protein (KAP) genes may lead to production of fibre types with improved processing and wearing qualities. Using this approach, we have demonstrated that high level cortical-specific expression of a wool type II intermediate filament (IF) keratin gene, K2.10, leads to marked alterations in both the microstructure and macrostructure of the wool fibres, which have higher lustre and reduced crimp. Analysis of mRNA found reduced levels of transcripts from endogenous cortical type I (p < 0.05) and type II (p < 0.01) keratin IF genes and from the KAP8 (p < 0.001) and KAP2 (p < 0.01) gene families. Examination of protein composition revealed an altered ratio in the keratin type II protein family of the wool fibre cortex. Whilst the over-expressed K2.10 transgene product constituted the majority of keratin type II IF protein, it appeared unable to form heterodimers with much of the expressed endogenous keratin type I IF. In comparison with non-transgenic sheep, fewer IF microfibrils were visible in the cortical cells of fibres from transgenics. The combined effect on fibre structure was disruption of the formation of orthocortical and paracortical cells in the fibre cortex, a factor which could account for the reduction in fibre crimp. No effects upon transcript or protein levels, or fibre microstructure or macrostructure were observed in transgenic sheep expressing the transgene at lower levels, indicating that subtle changes to the gene expression profile in sheep wool follicles can be tolerated. The data here also illustrate that control over endogenous transcript levels in the cortex results when factors acting on the endogenous keratin type I, keratin type II and KAP gene sequences are sequestered by the active K2.10 transgene locus. Moreover, interference to a transcriptional hierarchy shared by keratin and KAP genes may occur prior to establishment of the orthocortical and paracortical compartments of the follicle cortex, at the level of the chromatin.
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Affiliation(s)
- C S Bawden
- Department of Animal Science, University of Adelaide, Glen Osmond, South Australia
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12
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13
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Affiliation(s)
- M Manabe
- Department of Dermatology, Juntendo University School of Medicine, Tokyo, Japan
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14
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Waseem A, White K, Waseem NH. Identification of a novel keratin epitope: evidence for association between non-helical sub-domains L12 during filament assembly. Int J Biochem Cell Biol 1997; 29:971-83. [PMID: 9375377 DOI: 10.1016/s1357-2725(97)00055-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Keratin filaments in simple epithelial cells are heteropolymers of keratin 8 (K8) and keratin 18 (K18) polypeptides. The assembly of these polypeptides into intermediate filaments is a complex multi-stage phenomenon that involves several levels of associations. These molecular associations are not very well characterized. Monoclonal antibodies (MAbs) with defined specificities can be used to probe these associations and to isolate various intermediates in the assembly pathway. Here we describe the specificity of a MAb LE65 that has been widely used in keratin expression studies. We report that the MAb LE65 does not recognize individual keratin polypeptides but it instead reacts with a complex of K8 with K18. The MAb also did not react with complexes of K8 or K18 with other keratins. By allowing the antibody to react with complexes reconstituted from keratin fragments plus the complementary keratin, we have mapped the MAb LE65 epitope on the L12 sub-domains of K18, residues 214-231, and K8, residues 234-265, which must associate together to achieve antibody binding. These results suggest that the non-helical linkers, L12, of complementary keratins associate directly during filament assembly. This would explain why microinjection of MAb LE65 has been shown to disrupt keratin filaments. Furthermore, it may also help to explain the mechanism of filament disruption in some skin blistering syndromes induced by spontaneous mutations in the L12 region.
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Affiliation(s)
- A Waseem
- Department of Craniofacial Development, UMDS, Guy's Hospital, London, U.K
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15
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Noben-Trauth K, Naggert JK, Nishina PM. Cloning and expression analysis of mouse Cclp1, a new gene encoding a coiled-coil-like protein. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1352:133-7. [PMID: 9199242 DOI: 10.1016/s0167-4781(97)00050-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Here we describe the nucleotide sequence and expression pattern of a novel gene termed Coiled-coil-like protein 1 (Cclp1). A 2646bp open reading frame encodes a 882 amino acid protein with a predicted coiled-coil domain at the amino terminus. Cclp1 is expressed in a variety of adult tissues and during different stages of embryogenesis. The broad expression pattern suggests a general cellular function of CCLP1.
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16
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Abstract
Amyotrophic lateral sclerosis is a fatal neurodegenerative disease in which upper and lower motoneurons progressively deteriorate and die. Neuronal damage is most evident in the lower central nervous system, and death generally occurs following central respiratory failure. Proposed and demonstrated mechanisms for amyotrophic lateral sclerosis are diverse, and include altered superoxide dismutase and neurofilament proteins, autoimmune attack, and hyperglutamatergic activity. However, they do not account for the late onset of the disease, its earlier onset in males, and the differential vulnerability of neurons located in the brainstem and spinal cord. It is proposed here that, within the context of a specific defect such as altered superoxide dismutase, age-dependent decline in ascorbate availability triggers the disease. A role for ascorbate, which is found in millimolar levels in neurons, is suggested by a number of consistencies: 1) superoxide radicals being a common substrate for superoxide dismutase and ascorbate; 2) a close association between central nervous system ascorbate levels and injury tolerance; 3) a steady decline in ascorbate plasma levels and cellular availability with age; 4) plasma ascorbate levels being lower in males; 5) an association of ascorbate release with motor activity in central nervous system regions, in vivo; 6) the coupling of brain-cell ascorbate release with glutamate uptake; 7) possible roles for ascorbate modulation of N-methyl-D-aspartate receptor activity; 9) the ability of ascorbate to prevent peroxynitrite anion formation; and 10) evidence supporting the scorbutic guinea pig as a model for amyotrophic lateral sclerosis. Emphasis is placed on the probable competition between superoxide dismutase and ascorbate within the context of a primary defect of metal-binding or metal access in high-concentration proteins such as superoxide dismutase and human heavy neurofilaments. Finally, distinct features of alpha-motoneuronal physiology suggest that cell physiological characteristics such as high metabolic activity and extensive calcium dynamics may render neurons differentially vulnerable in amyotrophic lateral sclerosis.
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Affiliation(s)
- A B Kok
- Science Applications International Corporation, Joppa, Maryland 21085, USA.
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17
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Powell BC, Rogers GE. The role of keratin proteins and their genes in the growth, structure and properties of hair. EXS 1997; 78:59-148. [PMID: 8962491 DOI: 10.1007/978-3-0348-9223-0_3] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The importance of wool in the textile industry has inspired extensive research into its structure since the 1960s. Over the past several years, however, the hair follicle has increased in significance as a system for studying developmental events and the process of terminal differentiation. The present chapter seeks to integrate the expanding literature and present a broad picture of what we know of the structure and formation of hair at the cellular and molecular level. We describe in detail the hair keratin proteins and their genes, their structure, function and regulation in the hair follicle, and also the major proteins and genes of the inner and outer root sheaths. We discuss hair follicle development with an emphasis on the factors involved and describe some hair genetic diseases and transgenic and gene knockout models because, in some cases, they stimulate natural mutations that are advancing our understanding of cellular interactions in the formation of hair.
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Affiliation(s)
- B C Powell
- Department of Biochemistry, University of Adelaide, South Australia
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Abstract
The human prostate is composed of a series of tubular-alveolar glands and their ducts surrounded by a fibro-muscular stroma. The parenchymal glands secrete the seminal fluid and are anatomically arranged into the central, peripheral, and transitional zones. In this chapter the pattern of intermediate filament expression by the various epithelial components of the ducts, tubuloalveolar glands, and stroma are described. The changes which occur during malignant transformation from normal glands to prostatic intraepithelial neoplasia and subsequent invasive carcinoma are presented. The usefulness of cytokeratin markers in the diagnosis of prostate carcinoma is also discussed.
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Affiliation(s)
- R B Nagle
- Department of Pathology, University of Arizona Health Sciences Center, Tucson 85724-5043, USA
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19
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Goldman RD, Khuon S, Chou YH, Opal P, Steinert PM. The function of intermediate filaments in cell shape and cytoskeletal integrity. J Biophys Biochem Cytol 1996; 134:971-83. [PMID: 8769421 PMCID: PMC2120965 DOI: 10.1083/jcb.134.4.971] [Citation(s) in RCA: 270] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
This study describes the development and use of a specific method for disassembling intermediate filament (IF) networks in living cells. It takes advantage of the disruptive effects of mimetic peptides derived from the amino acid sequence of the helix initiation 1A domain of IF protein chains. The results demonstrate that at 1:1 molar ratios, these peptides disassemble vimentin IF into small oligomeric complexes and monomers within 30 min at room temperature in vitro. Upon microinjection into cultured fibroblasts, these same peptides induce the rapid disassembly of IF networks. The disassembly process is accompanied by a dramatic alteration in cell shape and the destabilization of microtubule and actin-stress fiber networks. These changes in cell shape and IF assembly states are reversible. The results are discussed with respect to the roles of IF in cell shape and the maintenance of the integrity and mechanical properties of the cytoplasm, as well as the stability of the other major cytoskeletal systems.
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Affiliation(s)
- R D Goldman
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA
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Fink P, Rogers MA, Korge B, Winter H, Schweizer J. A cDNA encoding the human type I hair keratin hHal. BIOCHIMICA ET BIOPHYSICA ACTA 1995; 1264:12-4. [PMID: 7578244 DOI: 10.1016/0167-4781(95)00122-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A full-length cDNA of a human type I hair keratin was isolated that encodes a protein of 416 amino acids. Northern blot analysis shows that the mRNA is present in human scalp but not in hairless skin. Based on sequence homology comparisons with the four known mouse type I hair keratins mHal-4 the keratin could be identified as the human hair keratin hHal.
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Affiliation(s)
- P Fink
- German Cancer Research Center, Research Program 2 (Tumor Cell Regulation), Heidelberg, Germany
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