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Abstract
Desmosomes are intercellular junctions whose primary function is strong intercellular adhesion, known as hyperadhesion. In the present review, we discuss how their structure appears to support this function as well as how they are assembled and down-regulated. Desmosomal components also have signalling functions that are important in tissue development and remodelling. Their adhesive and signalling functions are both compromised in genetic and autoimmune diseases that affect the heart, skin and mucous membranes. We conclude that much work is required on structure–function relationships within desmosomes in vivo and on how they participate in signalling processes to enhance our knowledge of tissue homoeostasis and human disease.
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Hobbs RP, Han SY, van der Zwaag PA, Bolling MC, Jongbloed JDH, Jonkman MF, Getsios S, Paller AS, Green KJ. Insights from a desmoplakin mutation identified in lethal acantholytic epidermolysis bullosa. J Invest Dermatol 2010; 130:2680-3. [PMID: 20613772 DOI: 10.1038/jid.2010.189] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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53
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Pieperhoff S, Barth M, Rickelt S, Franke WW. Desmosomal molecules in and out of adhering junctions: normal and diseased States of epidermal, cardiac and mesenchymally derived cells. Dermatol Res Pract 2010; 2010:139167. [PMID: 20671973 PMCID: PMC2909724 DOI: 10.1155/2010/139167] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Accepted: 03/23/2010] [Indexed: 11/18/2022] Open
Abstract
Current cell biology textbooks mention only two kinds of cell-to-cell adhering junctions coated with the cytoplasmic plaques: the desmosomes (maculae adhaerentes), anchoring intermediate-sized filaments (IFs), and the actin microfilament-anchoring adherens junctions (AJs), including both punctate (puncta adhaerentia) and elongate (fasciae adhaerentes) structures. In addition, however, a series of other junction types has been identified and characterized which contain desmosomal molecules but do not fit the definition of desmosomes. Of these special cell-cell junctions containing desmosomal glycoproteins or proteins we review the composite junctions (areae compositae) connecting the cardiomyocytes of mature mammalian hearts and their importance in relation to human arrhythmogenic cardiomyopathies. We also emphasize the various plakophilin-2-positive plaques in AJs (coniunctiones adhaerentes) connecting proliferatively active mesenchymally-derived cells, including interstitial cells of the heart and several soft tissue tumor cell types. Moreover, desmoplakin has also been recognized as a constituent of the plaques of the complexus adhaerentes connecting certain lymphatic endothelial cells. Finally, we emphasize the occurrence of the desmosomal transmembrane glycoprotein, desmoglein Dsg2, out of the context of any junction as dispersed cell surface molecules in certain types of melanoma cells and melanocytes. This broadening of our knowledge on the diversity of AJ structures indicates that it may still be too premature to close the textbook chapters on cell-cell junctions.
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Affiliation(s)
- Sebastian Pieperhoff
- Helmholtz Group for Cell Biology, German Cancer Research Center, Im Neuenheimer Feld 581, 69120 Heidelberg, Germany
- Department of Zoology and Faculty of Land and Food Systems, University of British Columbia, 2357 Main Mall, Vancouver, BC, Canada V6T 1Z4
| | - Mareike Barth
- Helmholtz Group for Cell Biology, German Cancer Research Center, Im Neuenheimer Feld 581, 69120 Heidelberg, Germany
| | - Steffen Rickelt
- Helmholtz Group for Cell Biology, German Cancer Research Center, Im Neuenheimer Feld 581, 69120 Heidelberg, Germany
| | - Werner W. Franke
- Helmholtz Group for Cell Biology, German Cancer Research Center, Im Neuenheimer Feld 581, 69120 Heidelberg, Germany
- Progen Biotechnik GmbH, Maaßstraße 30, 69123 Heidelberg, Germany
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Abstract
The structure, function, and regulation of desmosomal adhesion in vivo are discussed. Most desmosomes in tissues exhibit calcium-independent adhesion, which is strongly adhesive or “hyperadhesive”. This is fundamental to tissue strength. Almost all studies in culture are done on weakly adhesive, calcium-dependent desmosomes, although hyperadhesion can be readily obtained in confluent cell culture. Calcium dependence is a default condition in vivo, found in wounds and embryonic development. Hyperadhesion appears to be associated with an ordered arrangement of the extracellular domains of the desmosomal cadherins, which gives rise to the intercellular midline identified in ultrastructural studies. This in turn probably depends on molecular order in the desmosomal plaque. Protein kinase C downregulates hyperadhesion and there is preliminary evidence that it may also be regulated by tyrosine kinases. Downregulation of desmosomes in vivo may occur by internalisation of whole desmosomes rather than disassembly. Hyperadhesion has implications for diseases such as pemphigus.
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55
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Exploring the Nature of Desmosomal Cadherin Associations in 3D. Dermatol Res Pract 2010; 2010:930401. [PMID: 20672011 PMCID: PMC2905946 DOI: 10.1155/2010/930401] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 02/17/2010] [Accepted: 04/16/2010] [Indexed: 12/01/2022] Open
Abstract
Desmosomes are a complex assembly of protein molecules that mediate adhesion between adjacent cells. Desmosome composition is well established and spatial relationships between components have been identified. Intercellular cell-cell adhesion is created by the interaction of extracellular domains of desmosomal cadherins, namely, desmocollins and desmogleins. High-resolution methods have provided insight into the structural interactions between cadherins. However, there is a lack of understanding about the architecture of the intact desmosomes and the physical principles behind their adhesive strength are unclear. Electron Tomography (ET) studies have offered three-dimensional visual data of desmosomal cadherin associations at molecular resolution. This review discusses the merits of two cadherin association models represented using ET. We discuss the possible role of sample preparation on the structural differences seen between models and the possibility of adaptive changes in the structure as a direct consequence of mechanical stress and stratification.
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56
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Abstract
Intercalated disks (ICDs) are highly organized cell-cell adhesion structures, which connect cardiomyocytes to one another. They are composed of three major complexes: desmosomes, fascia adherens, and gap junctions. Desmosomes and fascia adherens junction are necessary for mechanically coupling and reinforcing cardiomyocytes, whereas gap junctions are essential for rapid electrical transmission between cells. Because human genetics and mouse models have revealed that mutations and/or deficiencies in various ICD components can lead to cardiomyopathies and arrhythmias, considerable attention has focused on the biologic function of the ICD. This review will discuss recent scientific developments related to the ICD and focus on its role in regulating cardiac muscle structure, signaling, and disease.
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Affiliation(s)
- Farah Sheikh
- Department of Medicine, University of California-San Diego, CA 92093, USA
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57
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Bon E, Steegers R, Steegers EAP, Ursem N, Charif H, Burgers PC, Luider TM, Dekker LJM. Proteomic analyses of the developing chicken cardiovascular system. J Proteome Res 2010; 9:268-74. [PMID: 19874049 DOI: 10.1021/pr900614w] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Up until today, no proteomics approaches have been described for heart muscle development. We describe a proteomics method to study the proteome of different heart structures at three stages of chicken embryonic development. For this purpose, a combination of gel separation, nanoLC separation and mass spectrometry was used. With this method, we identified in total 267 proteins in different tissue structures of chicken heart. We observed differences in protein abundance for a number of proteins between the different tissue structures and time points of development using spectral counting as a semiquantitative measure of protein abundance. For myosin-heavy chain 6, myosin-heavy chain 7, titin, connectin, collagen alpha-1, and xin, differences in protein levels for the different stages and structures (great arteries, outflow tract and ventricles) have been observed. A pathway analysis is performed in which the identified proteins are related to theoretical protein networks. Most prominent was the 'cardiovascular system development and function' network with the abundantly present proteins myosin 6 and myosin 7. We showed that myosin 6 is highly regulated in a stage and heart tissue specific manner. In conclusion, this method can be used to study changes in protein levels of chicken heart tissue in a spatiotemporal manner.
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Affiliation(s)
- Els Bon
- Laboratories of Neuro-Oncology & Clinical and Cancer Proteomics, Department of Neurology, Erasmus MC, The Netherlands
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58
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Bolling M, Veenstra M, Jonkman M, Diercks G, Curry C, Fisher J, Pas H, Bruckner A. Lethal acantholytic epidermolysis bullosa due to a novel homozygous deletion in DSP
: expanding the phenotype and implications for desmoplakin function in skin and heart. Br J Dermatol 2010; 162:1388-94. [DOI: 10.1111/j.1365-2133.2010.09668.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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59
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Gallicano GI, Mishra L. Hepatocytes from induced pluripotent stem cells: a giant leap forward for hepatology. Hepatology 2010; 51:20-2. [PMID: 20034034 PMCID: PMC3821555 DOI: 10.1002/hep.23474] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- G. Ian Gallicano
- Department of Biochemistry, and Molecular and Cellular Biology, Georgetown University Medical School, Washington, DC
| | - Lopa Mishra
- Department of Surgery, Georgetown University Medical School, Washington, DC,Department of Gastroenterology and Cancer Biology, University of Texas M.D. Anderson Cancer Center, Houston, TX
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60
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Franke WW, Rickelt S, Barth M, Pieperhoff S. The junctions that don't fit the scheme: special symmetrical cell-cell junctions of their own kind. Cell Tissue Res 2009; 338:1-17. [PMID: 19680692 PMCID: PMC2760712 DOI: 10.1007/s00441-009-0849-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Accepted: 07/16/2009] [Indexed: 02/07/2023]
Abstract
Immunocytochemical, electron-, and immunoelectron-microscopical studies have revealed that, in addition to the four major "textbook categories" of cell-cell junctions (gap junctions, tight junctions, adherens junctions, and desmosomes), a broad range of other junctions exists, such as the tiny puncta adhaerentia minima, the taproot junctions (manubria adhaerentia), the plakophilin-2-containing adherens junctions of mesenchymal or mesenchymally derived cell types including malignantly transformed cells, the composite junctions (areae compositae) of the mature mammalian myocardium, the cortex adhaerens of the eye lens, the interdesmosomal "sandwich" or "stud" junctions in the subapical layers of stratified epithelia and the tumors derived therefrom, and the complexus adhaerentes of the endothelial and virgultar cells of the lymph node sinus. On the basis of their sizes and shapes, other morphological criteria, and their specific molecular ensembles, these junctions and the genes that encode them cannot be subsumed under one of the major categories mentioned above but represent special structures in their own right, appear to serve special functions, and can give rise to specific pathological disorders.
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Affiliation(s)
- Werner W Franke
- Helmholtz Group for Cell Biology, German Cancer Research Center, 69120, Heidelberg, Germany.
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61
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62
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Asimaki A, Syrris P, Ward D, Guereta LG, Saffitz JE, McKenna WJ. Unique epidermolytic bullous dermatosis with associated lethal cardiomyopathy related to novel desmoplakin mutations. J Cutan Pathol 2009; 36:553-9. [DOI: 10.1111/j.1600-0560.2008.01112.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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63
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Altered desmoplakin expression at transcriptional and protein levels provides prognostic information in human oropharyngeal cancer. Hum Pathol 2009; 40:1320-9. [PMID: 19386346 DOI: 10.1016/j.humpath.2009.02.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Revised: 02/09/2009] [Accepted: 02/10/2009] [Indexed: 11/23/2022]
Abstract
Desmoplakin, a desmosomal component, is a key protein involved in cell-cell adhesion. Down-regulation of desmosomal proteins is associated with the invasive and metastatic ability of tumor cells. We examined 37 cases of human primary oropharyngeal squamous cell carcinomas lacking overt distant metastases to gain further insights on the potential role of desmoplakin in oral cancer. Desmoplakin expression was evaluated using reverse transcriptase-polymerase chain reaction and immunohistochemistry on frozen unfixed sections. Western blotting was performed to characterize the relative expression levels for each of the 2 desmoplakin protein isoforms, I and II. Desmoplakin expression was compared with histopathological grade, clinical stage, and patient outcome. Desmoplakin expression was prominent in highly differentiated tumors and reduced or absent in poorly differentiated tumors that developed distant metastases within the 3 years of follow-up period. Desmoplakin mRNA levels tracked with protein levels, suggesting that lack of desmoplakin protein expression is due to down-regulation of mRNA expression at the transcription level. Western blot analysis demonstrated that the 2 desmoplakin isoforms displayed different patterns of subcellular distribution in tumors, with the desmoplakin II detected only in patients in which desmoplakin immunoreactivity displayed an abnormal cytoplasmic localization. Our findings suggest that down-regulation of desmoplakin expression may represent a useful marker for evaluating the risk of distant metastasis formation in oropharyngeal squamous cell carcinomas. Interestingly, desmoplakin II was detected only in tumors associated with a poor clinical outcome, suggesting a potential specific function for this isoform in oral carcinogenesis. Characterizing DSP expression may improve evaluation risk of distant metastasis formation in oral cancer patients.
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64
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Pyle AL, Li B, Maupin AB, Guzman RJ, Crimmins DL, Olson S, Atkinson JB, Young PP. Biomechanical stress induces novel arterial intima-enriched genes: implications for vascular adaptation to stress. Cardiovasc Pathol 2009; 19:e13-20. [PMID: 19211270 DOI: 10.1016/j.carpath.2008.12.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Revised: 12/11/2008] [Accepted: 12/19/2008] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND The arterial vasculature is subjected to considerably greater biomechanical stress than the venous circulation. This is reflected in the difference in morphology between large arteries and veins, however little is known about the molecular differences that arise as a consequence of biomechanical stress. Previously, we identified a group of arterial intima-enriched (AIE) genes: sciellin, periplakin, SPRR3, envoplakin, galectin 7, and plakoglobin that are functionally related in that they contribute to the stress properties of stratified epithelium. We sought to test our hypothesis that these genes were regulated by biomechanical stress in vascular smooth muscle cells (VSMCs). METHODS Immunofluorescence was employed to determine the expression of the AIE genes in saphenous vein coronary artery bypass grafts. Furthermore, we used a model of cyclic stress to determine if the AIE genes were regulated by biomechanical stress in VSMCs in vitro. RESULTS Sciellin and periplakin were upregulated in saphenous vein coronary artery bypass grafts after arterialization, but were absent in non-arterialized saphenous veins. Sciellin, SPRR3, and periplakin transcripts were all upregulated (4.67-, 4.95-, 2.77-fold, respectively) by prolonged exposure to cyclic strain (24-72 h), but not at earlier time points. CONCLUSIONS These findings suggest a novel role for several human AIE genes in the VSMC response to arterialization and extended cyclic strain. SUMMARY Biomechanical stress has long been implicated in vascular pathologies. We report the novel finding of a group of genes, previously studied in stratified epithelium, that were regulated by prolonged cyclic stress in vascular smooth muscle cells. This may have important implications to vascular disease.
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Affiliation(s)
- Amy L Pyle
- Department of Pathology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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65
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Miri K, Varmuza S. Chapter 5 Imprinting and Extraembryonic Tissues—Mom Takes Control. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2009; 276:215-62. [DOI: 10.1016/s1937-6448(09)76005-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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66
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Moll R, Sievers E, Hämmerling B, Schmidt A, Barth M, Kuhn C, Grund C, Hofmann I, Franke WW. Endothelial and virgultar cell formations in the mammalian lymph node sinus: endothelial differentiation morphotypes characterized by a special kind of junction (complexus adhaerens). Cell Tissue Res 2008; 335:109-41. [PMID: 19015886 DOI: 10.1007/s00441-008-0700-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Accepted: 09/15/2008] [Indexed: 12/25/2022]
Abstract
The lymph node sinus are channel structures of unquestionable importance in immunology and pathology, specifically in the filtering of the lymph, the transport and processing of antigens, the adhesion and migration of immune cells, and the spread of metastatic cancer cells. Our knowledge of the cell and molecular biology of the sinus-forming cells is still limited, and the origin and biological nature of these cells have long been a matter of debate. Here, we review the relevant literature and present our own experimental results, in particular concerning molecular markers of intercellular junctions and cell differentiation. We show that both the monolayer cells lining the sinus walls and the intraluminal virgultar cell meshwork are indeed different morphotypes of the same basic endothelial cell character, as demonstrated by the presence of a distinct spectrum of general and lymphatic endothelial markers, and we therefore refer to these cells as sinus endothelial/virgultar cells (SEVCs). These cells are connected by unique adhering junctions, termed complexus adhaerentes, characterized by the transmembrane glycoprotein VE-cadherin, combined with the desmosomal plaque protein desmoplakin, several adherens junction plaque proteins including alpha- and beta-catenin and p120 catenin, and components of the tight junction ensemble, specifically claudin-5 and JAM-A, and the plaque protein ZO-1. We show that complexus adhaerentes are involved in the tight three-dimensional integration of the virgultar network of SEVC processes along extracellular guidance structures composed of paracrystalline collagen bundle "stays". Overall, the SEVC system might be considered as a local and specific modification of the general lymphatic vasculature system. Finally, physiological and pathological alterations of the SEVC system will be presented, and the possible value of the molecular markers described in histological diagnoses of autochthonous lymph node tumors will be discussed.
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Affiliation(s)
- Roland Moll
- Institute of Pathology, Philipps University of Marburg, 35033 Marburg, Germany.
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67
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Hofmann I, Kuhn C, Franke WW. Protein p0071, a major plaque protein of non-desmosomal adhering junctions, is a selective cell-type marker. Cell Tissue Res 2008; 334:381-99. [PMID: 19005682 DOI: 10.1007/s00441-008-0725-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Accepted: 10/14/2008] [Indexed: 12/01/2022]
Abstract
Protein p0071, which originally was introduced as a member of the p120-subfamily of armadillo proteins, common to desmosomes and adhaerens junctions (AJs) and to several other cell structures (centrosomes, midbodies), has been localized by using a series of novel mono- and polyclonal antibodies generated against various domains of the molecule. By protein analysis and immunolocalization techniques, protein p0071 has been localized as a plaque protein in AJs of diverse epithelia and certain vascular endothelia, in the composite junctions (areal compositae) of the intercalated disks of cardiomyocytes, and in the punctate or more extended AJs of the vast majority of cell culture types examined, including mitotic states. Using these antibodies, we have also shown that this AJ protein occurs only rarely or is even absent in tissues such as skeletal and smooth muscles, in a series of mesenchymal tissue cells, and in specific desmosome-rich cells such as those of the upper layers of the epidermis and certain other stratified epithelia and Hassall corpuscles of the thymus. We have also demonstrated that p0071 is absent from desmosomes. The occurrence of two major subtypes of lymphatic endothelial cells, one with AJs containing p0071 and one without detectable p0071, is emphasized. Possible structural and functional roles of p0071 are discussed in light of these new findings regarding its localization, and the addition of p0071 to the armamentarium of cytodiagnostic cell-type markers is recommended.
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Affiliation(s)
- Ilse Hofmann
- Joint Research Division Vascular Biology of the Medical Faculty Mannheim, University of Heidelberg, German Cancer Research Center (DKFZ) at Mannheim, CBTM, Ludolf-Krehl-Strasse 13-17, 68167 Mannheim, Germany.
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68
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Dejana E, Orsenigo F, Molendini C, Baluk P, McDonald DM. Organization and signaling of endothelial cell-to-cell junctions in various regions of the blood and lymphatic vascular trees. Cell Tissue Res 2008; 335:17-25. [PMID: 18855014 DOI: 10.1007/s00441-008-0694-5] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Accepted: 09/03/2008] [Indexed: 01/19/2023]
Abstract
Adhesive intercellular junctions between endothelial cells are formed by tight junctions and adherens junctions. In addition to promoting cell-to-cell adhesion, these structures regulate paracellular permeability, contact inhibition of endothelial cell growth, cell survival, and maintenance of cell polarity. Furthermore, adherens junctions are required for the correct organization of new vessels during embryo development or during tissue proliferation in the adult. Extensive research on cultured epithelial and endothelial cells has resulted in the identification of many molecular components of tight junctions and adherens junctions. Such studies have revealed the complexity of these structures, which are formed by membrane-associated adhesion proteins and a network of several intracellular signaling partners. This review focuses on the structural organization of junctional structures and their functional interactions in the endothelium of blood vessels and lymphatics. We emphasize the way that these structures regulate endothelial cell homeostasis by transferring specific intracellular signals and by modulating activation and signaling of growth factor receptors.
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Affiliation(s)
- Elisabetta Dejana
- IFOM , FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy.
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69
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Zohlnhöfer D, Nührenberg TG, Haas F, Bengel F, Schömig A, Baeuerle PA, Schwaiger M. Myocardial gene expression of matched hibernating and control tissue from patients with ischemic left ventricular dysfunction. Heart Vessels 2008; 23:230-42. [DOI: 10.1007/s00380-007-1035-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Accepted: 11/30/2007] [Indexed: 12/26/2022]
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70
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Nyqvist D, Giampietro C, Dejana E. Deciphering the functional role of endothelial junctions by using in vivo models. EMBO Rep 2008; 9:742-7. [PMID: 18600233 DOI: 10.1038/embor.2008.123] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Accepted: 05/23/2008] [Indexed: 11/09/2022] Open
Abstract
Endothelial cell-to-cell junctions are vital for the formation and integrity of blood vessels. The main adhesive junctional complexes in endothelial cells, adherens junctions and tight junctions, are formed by transmembrane adhesive proteins that are linked to intracellular signalling partners and cytoskeletal-binding proteins. Gene inactivation and blocking antibodies in mouse models have revealed some of the functions of the individual junctional components in vivo, and are increasing our understanding of the functional role of endothelial cell junctions in angiogenesis and vascular homeostasis. Adherens-junction organization is required for correct vascular morphogenesis during embryo development. By contrast, the data available suggest that tight-junction proteins are not essential for vascular development but are necessary for endothelial barrier function.
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Affiliation(s)
- Daniel Nyqvist
- IFOM, FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy
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71
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Abstract
Desmosomes are patch-like intercellular adhering junctions ("maculae adherentes"), which, in concert with the related adherens junctions, provide the mechanical strength to intercellular adhesion. Therefore, it is not surprising that desmosomes are abundant in tissues subjected to significant mechanical stress such as stratified epithelia and myocardium. Desmosomal adhesion is based on the Ca(2+)-dependent, homo- and heterophilic transinteraction of cadherin-type adhesion molecules. Desmosomal cadherins are anchored to the intermediate filament cytoskeleton by adaptor proteins of the armadillo and plakin families. Desmosomes are dynamic structures subjected to regulation and are therefore targets of signalling pathways, which control their molecular composition and adhesive properties. Moreover, evidence is emerging that desmosomal components themselves take part in outside-in signalling under physiologic and pathologic conditions. Disturbed desmosomal adhesion contributes to the pathogenesis of a number of diseases such as pemphigus, which is caused by autoantibodies against desmosomal cadherins. Beside pemphigus, desmosome-associated diseases are caused by other mechanisms such as genetic defects or bacterial toxins. Because most of these diseases affect the skin, desmosomes are interesting not only for cell biologists who are inspired by their complex structure and molecular composition, but also for clinical physicians who are confronted with patients suffering from severe blistering skin diseases such as pemphigus. To develop disease-specific therapeutic approaches, more insights into the molecular composition and regulation of desmosomes are required.
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Affiliation(s)
- Jens Waschke
- Institute of Anatomy and Cell Biology, University of Würzburg, Koellikerstr. 6, 97070, Würzburg, Germany.
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72
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Tan X, Yuan Y, Zeng G, Apte U, Thompson MD, Cieply B, Stolz DB, Michalopoulos GK, Kaestner KH, Monga SP. Beta-catenin deletion in hepatoblasts disrupts hepatic morphogenesis and survival during mouse development. Hepatology 2008; 47:1667-1679. [PMID: 18393386 PMCID: PMC4449338 DOI: 10.1002/hep.22225] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
UNLABELLED Beta-catenin, the central component of the canonical Wnt pathway, plays important roles in the processes of liver regeneration, growth, and cancer. Previously, we identified temporal expression of beta-catenin during liver development. Here, we characterize the hepatic phenotype, resulting from the successful deletion of beta-catenin in the developing hepatoblasts utilizing Foxa3-cyclization recombination and floxed-beta-catenin (exons 2 through 6) transgenic mice. Beta-catenin loss in developing livers resulted in significantly underdeveloped livers after embryonic day 12 (E12) with lethality occurring at around E17 stages. Histology revealed an overall deficient hepatocyte compartment due to (1) increased cell death due to oxidative stress and apoptosis, and (2) diminished expansion secondary to decreased cyclin-D1 and impaired proliferation. Also, the remnant hepatocytes demonstrated an immature phenotype as indicated by high nuclear to cytoplasmic ratio, poor cell polarity, absent glycogen, and decreased expression of key liver-enriched transcription factors: CCAAT-enhancer binding protein-alpha and hepatocyte nuclear factor-4alpha. A paucity of primitive bile ducts was also observed. While the stem cell assays demonstrated no intrinsic defect in hematopoiesis, distorted hepatic architecture and deficient hepatocyte compartments resulted in defective endothelial cell organization leading to overall fetal pallor. CONCLUSION Beta-catenin regulates multiple, critical events during the process of hepatic morphogenesis, including hepatoblast maturation, expansion, and survival, making it indispensable to survival.
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Affiliation(s)
- Xinping Tan
- Department of Pathology, University of Pennsylvania, School of Medicine, Philadelphia, PA
| | - Youzhong Yuan
- Department of Surgery, University of Pennsylvania, School of Medicine, Philadelphia, PA
| | - Gang Zeng
- Department of Pathology, University of Pennsylvania, School of Medicine, Philadelphia, PA
| | - Udayan Apte
- Department of Pathology, University of Pennsylvania, School of Medicine, Philadelphia, PA
| | | | - Benjamin Cieply
- Department of Pathology, University of Pennsylvania, School of Medicine, Philadelphia, PA
| | - Donna B. Stolz
- Department of Pathology, University of Pennsylvania, School of Medicine, Philadelphia, PA
- Department of Cell Biology, University of Pennsylvania, School of Medicine, Philadelphia, PA
| | | | - Klaus H. Kaestner
- Department of Genetics, University of Pennsylvania, School of Medicine, Philadelphia, PA
| | - Satdarshan P.S. Monga
- Department of Pathology, University of Pennsylvania, School of Medicine, Philadelphia, PA
- Department of Medicine, University of Pennsylvania, School of Medicine, Philadelphia, PA
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Mechanisms of disease: molecular genetics of arrhythmogenic right ventricular dysplasia/cardiomyopathy. ACTA ACUST UNITED AC 2008; 5:258-67. [PMID: 18382419 DOI: 10.1038/ncpcardio1182] [Citation(s) in RCA: 180] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Accepted: 01/24/2008] [Indexed: 02/07/2023]
Abstract
Arrhythmogenic right ventricular dysplasia/cardiomyopathy is an inherited cardiomyopathy estimated to affect approximately 1 in 5,000 individuals. Cardinal manifestations include right ventricular enlargement and dysfunction, fibrofatty replacement of myocytes in the right ventricle, characteristic electrocardiographic abnormalities, and ventricular arrhythmia most commonly arising from the right ventricle. The disease is frequently familial and typically involves autosomal dominant transmission with low penetrance and variable expressivity. Approximately 50% of symptomatic individuals harbor a mutation in one of the five major components of the cardiac desmosome. Nevertheless, other genetic modifiers and environmental factors complicate the clinical management of mutation carriers as well as counseling of their relatives. This Review summarizes the known genetic mutations associated with arrhythmogenic right ventricular dysplasia/cardiomyopathy, describes possible origins of recurrent mutations, presents theories on the pathogenesis of disease following a mutation, and discusses the current issues surrounding clinical use of genetic analysis in the assessment of individuals with this condition.
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Muscular Integrity—A Matter of Interlinking Distinct Structures via Plectin. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008; 642:165-75. [DOI: 10.1007/978-0-387-84847-1_12] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Holthöfer B, Windoffer R, Troyanovsky S, Leube RE. Structure and function of desmosomes. ACTA ACUST UNITED AC 2007; 264:65-163. [PMID: 17964922 DOI: 10.1016/s0074-7696(07)64003-0] [Citation(s) in RCA: 150] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Desmosomes are prominent adhesion sites that are tightly associated with the cytoplasmic intermediate filament cytoskeleton providing mechanical stability in epithelia and also in several nonepithelial tissues such as cardiac muscle and meninges. They are unique in terms of ultrastructural appearance and molecular composition with cell type-specific variations. The dynamic assembly properties of desmosomes are important prerequisites for the acquisition and maintenance of tissue homeostasis. Disturbance of this equilibrium therefore not only compromises mechanical resilience but also affects many other tissue functions as becomes evident in various experimental scenarios and multiple diseases.
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Affiliation(s)
- Bastian Holthöfer
- Department of Anatomy and Cell Biology, Johannes Gutenberg University, 55128 Mainz, Germany
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76
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Abstract
Desmosomes are highly specialized anchoring junctions that link intermediate filaments to sites of intercellular adhesion, thus facilitating the formation of a supracellular scaffolding that distributes mechanical forces throughout a tissue. These junctions are thus particularly important for maintaining the integrity of tissues that endure physical stress, such as the epidermis and myocardium. The importance of the classic mechanical functions of desmosomal constituents is underscored by pathologies reported in animal models and an ever-expanding list of human mutations that target both desmosomal cadherins and their associated cytoskeletal anchoring proteins. However, the notion that desmosomes are static structures that exist simply to glue cells together belies their susceptibility to remodeling in response to environmental cues and their important tissue-specific roles in cell behavior and signaling. Here, we review the molecular blueprint of the desmosome and models for assembling its protein components to form an adhesive interface and the desmosomal plaque. We also discuss emerging evidence of supra-adhesive roles for desmosomal proteins in regulating tissue morphogenesis and homeostasis. Finally, we highlight the dynamic nature of these adhesive organelles, examining mechanisms in health and disease for modulating adhesive strength and stability of desmosomes.
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Affiliation(s)
- Kathleen J Green
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA.
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77
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Sonnenberg A, Liem RKH. Plakins in development and disease. Exp Cell Res 2007; 313:2189-203. [PMID: 17499243 DOI: 10.1016/j.yexcr.2007.03.039] [Citation(s) in RCA: 228] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2007] [Revised: 03/01/2007] [Accepted: 03/06/2007] [Indexed: 11/22/2022]
Abstract
Plakins are large multi-domain molecules that have various functions to link cytoskeletal elements together and to connect them to junctional complexes. Plakins were first identified in epithelial cells where they were found to connect the intermediate filaments to desmosomes and hemidesmosomes [Ruhrberg, C., and Watt, F.M. (1997). The plakin family: versatile organizers of cytoskeletal architecture. Curr Opin Genet Dev 7, 392-397.]. They were subsequently found to be important for the integrity of muscle cells. Most recently, they have been found in the nervous system, where their functions appear to be more complex, including cross-linking of microtubules (MTs) and actin filaments [Leung, C.L., Zheng, M., Prater, S.M., and Liem, R.K. (2001). The BPAG1 locus: Alternative splicing produces multiple isoforms with distinct cytoskeletal linker domains, including predominant isoforms in neurons and muscles. J Cell Biol 154, 691-697., Leung, C.L., Sun, D., Zheng, M., Knowles, D.R., and Liem, R.K. (1999). Microtubule actin cross-linking factor (MACF): a hybrid of dystonin and dystrophin that can interact with the actin and microtubule cytoskeletons. J Cell Biol 147, 1275-1286.]. These plakins have also indicated their relationship to the spectrin superfamily of proteins and the plakins appear to be evolutionarily related to the spectrins, but have diverged to perform different specialized functions. In invertebrates, a single plakin is present in both Drosophila melanogaster and Caenorhabditis elegans, which resemble the more complex plakins found in mammals [Roper, K., Gregory, S.L., and Brown, N.H. (2002). The 'spectraplakins': cytoskeletal giants with characteristics of both spectrin and plakin families. J Cell Sci 115, 4215-4225.]. In contrast, there are seven plakins found in mammals and most of them have alternatively spliced forms leading to a very complex group of proteins with potential tissue specific functions [Jefferson, J.J., Leung, C.L., and Liem, R.K. (2004). Plakins: goliaths that link cell junctions and the cytoskeleton. Nat Rev Mol Cell Biol 5, 542-553.]. In this review, we will first describe the plakins, desmoplakin, plectin, envoplakin and periplakin and then describe two other mammalian plakins, Bullous pemphigoid antigen 1 (BPAG1) and microtubule actin cross-linking factor 1 (MACF1), that are expressed in multiple isoforms in different tissues. We will also describe the relationship of these two proteins to the invertebrate plakins, shortstop (shot) in Drosophila and VAB-10 in C. elegans. Finally, we will describe an unusual mammalian plakin, called epiplakin.
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Affiliation(s)
- Arnoud Sonnenberg
- Division of Cell Biology, The Netherlands Cancer Inst., Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.
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78
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Pieperhoff S, Franke WW. The area composita of adhering junctions connecting heart muscle cells of vertebrates - IV: coalescence and amalgamation of desmosomal and adhaerens junction components - late processes in mammalian heart development. Eur J Cell Biol 2007; 86:377-91. [PMID: 17532539 DOI: 10.1016/j.ejcb.2007.04.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Revised: 04/16/2007] [Accepted: 04/17/2007] [Indexed: 12/17/2022] Open
Abstract
In the adult mammalian heart, the cardiomyocytes and thus their terminally anchored myofibrillar bundles are connected by large arrays of closely spaced or even fused adhering junctions (AJs), termed "intercalated disks" (IDs). In recent years, the ID complex has attracted special attention as it has become clear that several human hereditary cardiomyopathies are caused by mutations of genes encoding ID marker proteins, in particular some that are also known as constituents of epithelial desmosomes. Previously, we have shown that in the mature myocardial ID the compositional differences between desmosome-like and adhaerens junctions are, by and large, lost and a composite hybrid structure, the area composita, is formed. We now report results from immunofluorescence and (immuno-)electron microscopic studies of heart formation during mouse embryogenesis and postnatal growth and show that the formation of the IDs with extended area composita structures is a late, primarily postnatal process. While up to birth small distinct desmosomes and AJs are resolved as predominant ID structures, areae compositae of increasing sizes and merged marker protein patterns occupy most of the IDs in the mature heart. Differences in the patterns of ID formation and amalgamation of the two ensembles of junction proteins in time and space are also demonstrated. Together with corresponding observations during rat and human heart development our results indicate that ID topogenesis and area composita formation are also late developmental processes in other mammals. We discuss the importance of the ID and the areae compositae in cardiac functions and, consequently, in cardiomyopathies and possible myocardial regeneration processes.
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Affiliation(s)
- Sebastian Pieperhoff
- Division of Cell Biology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
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Lorch JH, Thomas TO, Schmoll HJ. Bortezomib inhibits cell-cell adhesion and cell migration and enhances epidermal growth factor receptor inhibitor-induced cell death in squamous cell cancer. Cancer Res 2007; 67:727-34. [PMID: 17234784 DOI: 10.1158/0008-5472.can-06-2162] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The lack of cell-cell adhesion and increased migration are key characteristics of cancer cells. The loss of expression of cell adhesion components and overexpression of components critical for cell migration, such as focal adhesion kinase (FAK), correlate with poor prognosis. Because alteration of protein turnover affects the expression levels and, in turn, may influence protein function, we investigated the effects of the proteasome inhibitor bortezomib on cell adhesion and migration in oral squamous cell cancer cell lines SCC68 and SCC15. Following treatment with bortezomib, protein levels of adherens junction components such as E-cadherin were unchanged. The desmosomal linker protein desmoplakin level was increased, whereas the protein level of the desmosomal cadherin, desmoglein 2, was diminished. Reduced desmoglein 2 levels correlated with the diminished strength of mechanical cell-cell adhesion. The protein level of the epidermal growth factor receptor (EGFR) increased after proteasome inhibition and EGFR inhibition with the EGFR-specific tyrosine kinase inhibitor PKI166 was able to restore cell-cell adhesion. Furthermore, we found that the combination of PKI166 with bortezomib enhanced the rate of cell death. Although the FAK protein level was unchanged following bortezomib treatment, recruitment of FAK phosphorylated at tyrosine residue 397 to the periphery of the cell was induced. Migration was reduced following treatment with bortezomib, which could potentially be explained by a prominent but disorganized actin fiber network revealed through immunofluorescence. Collectively, our results suggest that proteasome inhibition using bortezomib affects cell adhesion and cell migration profoundly and provides a rationale for its clinical use in conjunction with an EGFR inhibitor.
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Affiliation(s)
- Jochen H Lorch
- Department of Hematology and Oncology, Martin-Luther University Halle, Halle, Germany.
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80
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Wan H, South AP, Hart IR. Increased keratinocyte proliferation initiated through downregulation of desmoplakin by RNA interference. Exp Cell Res 2007; 313:2336-44. [PMID: 17475244 DOI: 10.1016/j.yexcr.2007.01.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2006] [Revised: 12/19/2006] [Accepted: 01/14/2007] [Indexed: 12/12/2022]
Abstract
The intercellular adhesive junction desmosomes are essential for the maintenance of tissue structure and integrity in skin. Desmoplakin (Dp) is a major obligate plaque protein which plays a fundamental role in anchoring intermediate filaments to desmosomal cadherins. Evidence from hereditary human disease caused by mutations in the gene encoding Dp, e.g. Dp haploinsufficiency, suggests that alterations in Dp expression result not only in the disruption of tissue structure and integrity but also could evoke changes in keratinocyte proliferation. We have used transient RNA interference (RNAi) to downregulate Dp specifically in HaCaT keratinocytes. We showed that this Dp downregulation also caused reduced expression of several other desmosomal proteins. Increased cell proliferation and enhanced G(1)-to-S-phase entry in the cell cycle, as monitored by colonial cellular density and BrdU incorporation, were seen in Dp RNAi-treated cells. These proliferative changes were associated with elevated phospho-ERK1/2 and phospho-Akt levels. Furthermore, this increase in phospho-ERK/1/2 and phospho-Akt levels was sustained in Dp RNAi-treated cells at confluence whereas in control cells there was a significant reduction in phosphorylation of ERK1/2. This study indicates that Dp may participate in the regulation of keratinocyte cell proliferation by, in part at least, regulating cell cycle progression.
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Affiliation(s)
- Hong Wan
- Centre for Tumour Biology, Institute of Cancer and CR-UK Clinical Centre, Barts and The London, Queen Mary's School of Medicine and Dentistry, John Vane Science Centre, Charterhouse Square, London, UK.
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81
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Kuijpers KAJ, Heesakkers JPFA, Jansen CFJ, Schalken JA. Cadherin-11 is expressed in detrusor smooth muscle cells and myofibroblasts of normal human bladder. Eur Urol 2007; 52:1213-21. [PMID: 17292535 DOI: 10.1016/j.eururo.2007.01.052] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2006] [Accepted: 01/12/2007] [Indexed: 10/23/2022]
Abstract
OBJECTIVES It has recently been found that detrusor smooth muscle cells and myofibroblasts are coupled via gap junctions. However, gap junctions cannot account for strong physical interaction between cells, which has prompted the search for intercellular adhesion molecules. Cadherin-11 is a candidate for such a molecule, since it mediates the interaction of dermal myofibroblasts in contractile wound granulation tissue. We therefore hypothesised that the physical adhesion between detrusor smooth muscle cells and myofibroblasts is mediated by cadherin-11. The aim of this study was to test this hypothesis. METHODS Bladder biopsies from eight radical cystectomy specimens were snap-frozen, sectioned, and stained for E-cadherin; cadherin-11; alpha-catenin; beta-catenin; gamma-catenin; and smooth muscle cell/myofibroblast markers connexin-43, vimentin, desmin, smooth muscle actin, and smoothelin. Specimens were analysed by using binocular epifluorescent and confocal laser-scanning microscopy. RESULTS Specific positive membranous expression of all adhesion complex molecules except E-cadherin was detected in detrusor suburothelial tissue. All biopsies showed a similar punctate pattern of expression for cadherin-11 within bundles of smooth muscle cells and a suburothelial layer of cells. Cadherin-11 was specifically located at the cell membrane, in distinct linear domains. CONCLUSIONS To our knowledge this is the first time evidence has been provided for cadherin-mediated smooth muscle and suburothelial myofibroblast cell-cell interaction in the human bladder. Cadherin-11 most probably plays an important role in the intercellular physical coupling of detrusor smooth muscle cells and also of myofibroblasts.
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Affiliation(s)
- Kamiel A J Kuijpers
- Department of Urology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
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82
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Desmoplakin Is Essential for Epidermal Sheet Formation. J Invest Dermatol 2007; 127 Suppl 3:E12. [DOI: 10.1038/sj.skinbio.6250005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Indexed: 11/08/2022]
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83
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Abstract
Homotypic cell-cell adhesion is essential for tissue and organ development, remodeling, regeneration, and physiological function. Whereas a significant number of homotypic cell-cell adhesion molecules have been identified, much more is known about those concentrated in epithelia than in endothelia. Among the endothelial cell-cell adhesion molecules, very little is known that is specific to endothelium in the pulmonary and bronchial circulations. This review focuses primarily on homotypic cell-cell adhesion molecules that are or are likely to be important in lung endothelium.
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Affiliation(s)
- D Michael Shasby
- Dept. of Internal Medicine, University of Iowa College of Medicine, 140E EMRB, Iowa City, IA 52242, USA.
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84
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Yang Z, Bowles NE, Scherer SE, Taylor MD, Kearney DL, Ge S, Nadvoretskiy VV, DeFreitas G, Carabello B, Brandon LI, Godsel LM, Green KJ, Saffitz JE, Li H, Danieli GA, Calkins H, Marcus F, Towbin JA. Desmosomal dysfunction due to mutations in desmoplakin causes arrhythmogenic right ventricular dysplasia/cardiomyopathy. Circ Res 2006; 99:646-55. [PMID: 16917092 DOI: 10.1161/01.res.0000241482.19382.c6] [Citation(s) in RCA: 221] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is characterized by progressive degeneration of the right ventricular myocardium, ventricular arrhythmias, fibrous-fatty replacement, and increased risk of sudden death. Mutations in 6 genes, including 4 encoding desmosomal proteins (Junctional plakoglobin (JUP), Desmoplakin (DSP), Plakophilin 2, and Desmoglein 2), have been identified in patients with ARVD/C. Mutation analysis of 66 probands identified 4 variants in DSP; V30M, Q90R, W233X, and R2834H. To establish a cause and effect relationship between those DSP missense mutations and ARVD/C, we performed in vitro and in vivo analyses of the mutated proteins. Unlike wild-type (WT) DSP, the N-terminal mutants (V30M and Q90R) failed to localize to the cell membrane in desomosome-forming cell line and failed to bind to and coimmunoprecipitate JUP. Multiple attempts to generate N-terminal DSP (V30M and Q90R) cardiac-specific transgenes have failed: analysis of embryos revealed evidence of profound ventricular dilation, which likely resulted in embryonic lethality. We were able to develop transgenic (Tg) mice with cardiac-restricted overexpression of the C-terminal mutant (R2834H) or WT DSP. Whereas mice overexpressing WT DSP had no detectable histologic, morphological, or functional cardiac changes, the R2834H-Tg mice had increased cardiomyocyte apoptosis, cardiac fibrosis, and lipid accumulation, along with ventricular enlargement and cardiac dysfunction in both ventricles. These mice also displayed interruption of DSP-desmin interaction at intercalated discs (IDs) and marked ultra-structural changes of IDs. These data suggest DSP expression in cardiomyocytes is crucial for maintaining cardiac tissue integrity, and DSP abnormalities result in ARVD/C by cardiomyocyte death, changes in lipid metabolism, and defects in cardiac development.
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Affiliation(s)
- Zhao Yang
- Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
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85
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Borrmann CM, Grund C, Kuhn C, Hofmann I, Pieperhoff S, Franke WW. The area composita of adhering junctions connecting heart muscle cells of vertebrates. II. Colocalizations of desmosomal and fascia adhaerens molecules in the intercalated disk. Eur J Cell Biol 2006; 85:469-85. [PMID: 16600422 DOI: 10.1016/j.ejcb.2006.02.009] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2005] [Revised: 02/14/2006] [Accepted: 02/15/2006] [Indexed: 12/17/2022] Open
Abstract
Using immunofluorescence histochemistry and immunoelectron microscopy on sections through myocardiac tissues of diverse mammalian (human, cow, rat, mouse) and fish species we show that both desmosomal and fascia adhaerens proteins identified by gel electrophoresis and immunoblot occur in the area composita, the by far major type of plaque-bearing junctions of the intercalated disks (IDs) connecting cardiomyocytes. Specifically, we demonstrate that desmoplakin and the other desmosomal proteins occur in these junctions, together with N-cadherin, cadherin-11, alpha- and beta-catenin as well as vinculin, afadin and proteins p120(ctn), ARVCF, p0071, and ZO-1, suggestive of colocalization. We conclude that the predominant type of adhering junction present in IDs is a junction sui generis, termed area composita, that is characterized by an unusually high molecular complexity and an intimate association of molecules of both ensembles, the desmosomal one and the fascia adhaerens category. We discuss possible myocardium-specific, complex-forming interactions between members of the two ensembles and the relevance of our findings for the formation and functioning of the heart and for the understanding of hereditary and other cardiomyopathies. We further propose to use this highly characteristic area composita ensemble of molecules as cardiomyocyte markers for the monitoring of cardiomyogenesis, cardiomyocyte regeneration and possible cardiomyocyte differentiation from mesenchymal stem cells.
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Affiliation(s)
- Carola M Borrmann
- Division of Cell Biology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany
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86
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Franke WW, Borrmann CM, Grund C, Pieperhoff S. The area composita of adhering junctions connecting heart muscle cells of vertebrates. I. Molecular definition in intercalated disks of cardiomyocytes by immunoelectron microscopy of desmosomal proteins. Eur J Cell Biol 2006; 85:69-82. [PMID: 16406610 DOI: 10.1016/j.ejcb.2005.11.003] [Citation(s) in RCA: 184] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2005] [Revised: 11/18/2005] [Accepted: 11/21/2005] [Indexed: 12/17/2022] Open
Abstract
Among sarcomeric muscles the cardiac muscle cells are unique by, inter alia, a systemic and extended cell-cell contact structure, the intercalated disk (ID), comprising frequent and closely spaced arrays of plaque-coated cell-cell adhering junctions (AJs). As some of these junctions may look somewhat like desmosomes and others like fasciae adhaerentes, the dogma has emerged in the literature that IDs contain - like epithelial cells - both kinds of AJs formed by - for the most - mutually exclusive molecular ensembles. This, however, is not the case. In comprehensive immunoelectron microscopic studies of mammalian (human, bovine, rat, mouse) and non-mammalian (chicken, amphibia, fishes) heart muscle tissues, we have localized major constituents of the desmosomal plaques of polar epithelia, desmoplakin, plakophilin-2 and plakoglobin, as well as the desmosomal cadherins, desmoglein Dsg2 and desmocollin Dsc2, in both kinds of ID AJs, independent of the specific morphological appearance. The desmosomal molecules are not restricted to the desmosome-like-looking junctions but can also be detected in junctions appearing similar to the zonula or fascia adhaerens structures. These AJs of cardiac ID are therefore subsumed under the collective term area composita. We discuss our results with respect to the importance of ID junction molecules for the formation, maintenance and function of the heart, particularly in relation to recent findings that deletions of - or mutations in - genes encoding such proteins can cause severe, sometimes lethal damages.
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Affiliation(s)
- Werner W Franke
- Division of Cell Biology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany.
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87
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Hämmerling B, Grund C, Boda-Heggemann J, Moll R, Franke WW. The complexus adhaerens of mammalian lymphatic endothelia revisited: a junction even more complex than hitherto thought. Cell Tissue Res 2005; 324:55-67. [PMID: 16372193 DOI: 10.1007/s00441-005-0090-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2005] [Accepted: 09/22/2005] [Indexed: 12/21/2022]
Abstract
The significance of a special kind of VE-cadherin-based, desmoplakin- and plakoglobin-containing adhering junction, originally identified in certain endothelial cells of the mammalian lymphatic system (notably the retothelial cells of the lymph node sinus and a subtype of lining endothelial cells of peripheral lymphatic vessels), has been widely confirmed and its importance in the formation of blood and lymph vessels has been demonstrated in vivo and in vitro. We have recently extended the molecular and structural characterization of the complexus adhaerens and can now report that it represents a rare and special combination of components known from three other major types of cell junction. It comprises zonula adhaerens proteins (VE-cadherin, alpha- and beta-catenin, protein p120(ctn), and afadin), desmosomal plaque components (desmoplakin and plakoglobin), and tight-junction proteins (claudin-5 and ZO-1) and forms junctions that vary markedly in size and shape. The special character and the possible biological roles of the complexus adhaerens and its unique ensemble of molecules in angiogenesis, immunology, and oncology are discussed. The surprising finding of claudin-5 and protein ZO-1 in substructures of retothelial cell-cell bridges, i.e. structures that do not separate different tissues or cell layer compartments, suggests that such tight-junction molecules are involved in functions other than the "fence" and "barrier" roles of zonulae occludentes.
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Affiliation(s)
- Bettina Hämmerling
- Division of Cell Biology, German Cancer Research Center, Im Neuenheimer Feld 280, D-69120, Heidelberg, Germany
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88
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Godsel LM, Hsieh SN, Amargo EV, Bass AE, Pascoe-McGillicuddy LT, Huen AC, Thorne ME, Gaudry CA, Park JK, Myung K, Goldman RD, Chew TL, Green KJ. Desmoplakin assembly dynamics in four dimensions: multiple phases differentially regulated by intermediate filaments and actin. J Cell Biol 2005; 171:1045-59. [PMID: 16365169 PMCID: PMC2171300 DOI: 10.1083/jcb.200510038] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2005] [Accepted: 11/17/2005] [Indexed: 12/16/2022] Open
Abstract
The intermediate filament (IF)-binding protein desmoplakin (DP) is essential for desmosome function and tissue integrity, but its role in junction assembly is poorly understood. Using time-lapse imaging, we show that cell-cell contact triggers three temporally overlapping phases of DP-GFP dynamics: (1) the de novo appearance of punctate fluorescence at new contact zones after as little as 3 min; (2) the coalescence of DP and the armadillo protein plakophilin 2 into discrete cytoplasmic particles after as little as 15 min; and (3) the cytochalasin-sensitive translocation of cytoplasmic particles to maturing borders, with kinetics ranging from 0.002 to 0.04 microm/s. DP mutants that abrogate or enhance association with IFs exhibit delayed incorporation into junctions, altering particle trajectory or increasing particle pause times, respectively. Our data are consistent with the idea that DP assembles into nascent junctions from both diffusible and particulate pools in a temporally overlapping series of events triggered by cell-cell contact and regulated by actin and DP-IF interactions.
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Affiliation(s)
- Lisa M Godsel
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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89
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Smith AN, Miller LAD, Song N, Taketo MM, Lang RA. The duality of β-catenin function: A requirement in lens morphogenesis and signaling suppression of lens fate in periocular ectoderm. Dev Biol 2005; 285:477-89. [PMID: 16102745 DOI: 10.1016/j.ydbio.2005.07.019] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2005] [Revised: 06/23/2005] [Accepted: 07/18/2005] [Indexed: 11/16/2022]
Abstract
In the current analysis, we have investigated both the cytoskeletal and signaling roles of beta-catenin during the early phases of lens development using conditional loss- and gain-of-function strategies. Conditional loss of beta-catenin in the presumptive lens does not perturb the normal sequential appearance of lens fate markers but results in a dramatic failure of the coordinated epithelial cell behavior that constitutes lens morphogenesis. Similarly, loss-of-function for Lrp6, the Wnt pathway coreceptor expressed in the eye primordium, does not prevent expression of lens induction markers. Surprisingly, conditional deletion of beta-catenin in periocular ectoderm results in the formation of Prox-1 and beta-crystallin-positive ectopic lentoid bodies. Combined with the observation that the Wnt pathway reporter TOPGAL is expressed in nasal periocular ectoderm, these data suggest that, in this location, the canonical Wnt signaling pathway normally suppresses lens fate in favor of other structures. Consistent with this proposal, a dominant-active form of beta-catenin causes a loss of lens fate and a complete absence of lens development when expressed in the presumptive lens ectoderm.
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Affiliation(s)
- April N Smith
- Division of Developmental Biology, Department of Ophthalmology, Children's Hospital Research Foundation, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
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90
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Gallicano GI, Foshay K, Pengetnze Y, Zhou X. Dynamics and unexpected localization of the plakin binding protein, kazrin, in mouse eggs and early embryos. Dev Dyn 2005; 234:201-14. [PMID: 16086310 DOI: 10.1002/dvdy.20519] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The cell uses the cytoskeleton in virtually every aspect of cell survival and function. One primary function of the cytoskeleton is to connect to and stabilize intercellular junctions. To accomplish this task, microtubules, actin filaments, and intermediate filaments utilize cytolinker proteins, which physically bind the cytoskeletal filament to the core proteins of the adhesion junction. The plakin family of linker proteins have been in the spotlight recently as critical components for embryo survival and, when mutated, the cause of diseases such as muscular dystrophy and cardiomyopathies. Here, we reveal the dynamics of a recently discovered plakin binding protein, kazrin (kaz), during early mouse development. Kaz was originally found in adult tissues, primarily epidermis, linking periplakin to the plasma membrane and colocalizing with desmoplakin in desmosomes. Using reverse transcriptase-polymerase chain reaction, Western blots, and confocal microscopy, we found kaz in unfertilized eggs associated with the spindle apparatus and cytoskeletal sheets. As quickly as 5 min after egg activation, kaz relocates to a diffuse peri-spindle position, followed 20-30 min later by clear localization to the presumptive cytokinetic ring. Before the blastocyst stage of development, kaz associates with the nuclear matrix in a cell cycle-dependent manner, and also associates with the cytoplasmic actin cytoskeleton. After blastocyst formation, kaz localization and potential function(s) become highly complex as it is found associating with cell-cell junctions, the cytoskeleton, and nucleus. Postimplantation stages of development reveal that kaz retains a multifunctional, tissue-specific role as it is detected at diverse locations in various embryonic tissue types.
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Affiliation(s)
- G Ian Gallicano
- Department of Cell Biology, Georgetown University Medical Center, Washington, DC 20007, USA.
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91
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Xiao K, Garner J, Buckley KM, Vincent PA, Chiasson CM, Dejana E, Faundez V, Kowalczyk AP. p120-Catenin regulates clathrin-dependent endocytosis of VE-cadherin. Mol Biol Cell 2005; 16:5141-51. [PMID: 16120645 PMCID: PMC1266414 DOI: 10.1091/mbc.e05-05-0440] [Citation(s) in RCA: 215] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
VE-cadherin is an adhesion molecule critical to vascular barrier function and angiogenesis. VE-cadherin expression levels are regulated by p120 catenin, which prevents lysosomal degradation of cadherins by unknown mechanisms. To test whether the VE-cadherin cytoplasmic domain mediates endocytosis, and to elucidate the nature of the endocytic machinery involved, the VE-cadherin tail was fused to the interleukin (IL)-2 receptor (IL-2R) extracellular domain. Internalization assays demonstrated that the VE-cadherin tail dramatically increased endocytosis of the IL-2R in a clathrin-dependent manner. Interestingly, p120 inhibited VE-cadherin endocytosis via a mechanism that required direct interactions between p120 and the VE-cadherin cytoplasmic tail. However, p120 did not inhibit transferrin internalization, demonstrating that p120 selectively regulates cadherin internalization rather than globally inhibiting clathrin-dependent endocytosis. Finally, cell surface labeling experiments in cells expressing green fluorescent protein-tagged p120 indicated that the VE-cadherin-p120 complex dissociates upon internalization. These results support a model in which the VE-cadherin tail mediates interactions with clathrin-dependent endocytic machinery, and this endocytic processing is inhibited by p120 binding to the cadherin tail. These findings suggest a novel mechanism by which a cytoplasmic binding partner for a transmembrane receptor can serve as a selective plasma membrane retention signal, thereby modulating the availability of the protein for endo-lysosomal processing.
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Affiliation(s)
- Kanyan Xiao
- Department of Dermatology, Emory University, Atlanta, GA 30322, USA
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92
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Sawa Y, Kuroshima SI, Yamaoka Y, Yoshida S. Intracellular Distribution of Desmoplakin in Human Odontoblasts. J Histochem Cytochem 2005; 53:1099-108. [PMID: 15933072 DOI: 10.1369/jhc.4a6525.2005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Coexpression of desmosomal proteins and vimentin has been reported in a specific mesenchymal phenotype. This study investigated the expression of vimentin-binding desmosomal proteins in human dental pulp fibroblasts (DPF) and odontoblasts. The dental pulp has no cells expressing desmocollin (DSC) 1–3, desmoglein (DSG) 1–3, junction plakoglobin (JUP), or desmoplakin (DPK) 1 and 2 except for odontoblasts expressing DPK. A confocal image by laser-scanning microscopy demonstrated the diffuse distribution of DPK in the cytoplasm throughout the odontoblast processes. In culture, the mRNA expression of JUP and DPK1, but not DSC1–3 and DSG1–3, was detected in all DPF clones tested and also in odontoblast-like cells (OB) expressing osteocalcin and dentin sialophosphoprotein mRNAs established in the differentiation medium. The DPF having the potential to differentiate into OB expressed vimentin, but not DPK before culturing in the differentiation medium, whereas OB expressed vimentin-binding DPK1. These results suggest that DPF usually expresses DPK1 mRNA, and that the DPK1 production and the bonding of vimentin to DPK1 occur in DPF with the differentiation into odontoblasts.
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Affiliation(s)
- Yoshihiko Sawa
- Department of Oral Functional Anatomy, Graduate School of Dental Medicine, Hokkaido University, Sapporo 060-8586, Japan.
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93
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Lai Cheong JE, Wessagowit V, McGrath JA. Molecular abnormalities of the desmosomal protein desmoplakin in human disease. Clin Exp Dermatol 2005; 30:261-6. [PMID: 15807686 DOI: 10.1111/j.1365-2230.2005.01736.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Desmoplakin is the principal plaque protein of desmosomes, specialized adhesion junctions found in various tissues including skin, heart and meninges. It is an entirely intracellular protein and in keratinocytes desmoplakin binds to other structural components of desmosomes such as cadherins and armadillo proteins, as well as to keratin filaments. Clues to the biological significance of desmoplakin have recently emerged from a number of naturally occurring human desmoplakin gene mutations. Both autosomal dominant and autosomal recessive disorders have been reported. The spectrum of clinical features includes varying degrees of keratoderma, blisters, nail dystrophy, woolly hair and, in some cases, cardiomyopathy. This review provides an update on genotype-phenotype correlation for human desmoplakin mutations as well as an overview of desmoplakin abnormalities in other conditions, including autoimmune blistering diseases, epithelial malignancies and blood vessel morphogenesis.
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Affiliation(s)
- J E Lai Cheong
- Genetic Skin Disease Group, St John's Institute of Dermatology, The Guy's, King's College and St Thomas' Hospitals' Medical School, Labeth Palace Road, London, SE1 7EH, UK
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94
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Hudson TY, Fontao L, Godsel LM, Choi HJ, Huen AC, Borradori L, Weis WI, Green KJ. In vitro methods for investigating desmoplakin-intermediate filament interactions and their role in adhesive strength. Methods Cell Biol 2005; 78:757-86. [PMID: 15646638 DOI: 10.1016/s0091-679x(04)78026-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Affiliation(s)
- Tracie Y Hudson
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA
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95
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Abstract
Defects in desmosome-mediated cell-cell adhesion can lead to tissue fragility syndromes. Both inherited and acquired diseases caused by desmosomal defects have been described. The two organs that appear most vulnerable to these defects are the skin with its appendages, and the heart. Furthermore, the analysis of genetically engineered mice has led to the discovery that desmosomal proteins are also required for normal embryonic development. Knockout mice for several desmosomal proteins die in utero. Depending on the protein studied, death occurs either around the time of implantation, at mid-gestation or shortly before birth. So far, it appears that structural defects leading to abnormal histo-architecture and tissue fragility are the main cause of death, i.e. there is no evidence that loss of a desmosomal protein would abort specific cell lineages or differentiation programs. Nevertheless, we are only beginning to understand the functions of individual desmosomal proteins during development. This review focuses on the role of desmosomes during mouse embryonic development.
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Affiliation(s)
- Xing Cheng
- Department of Dermatology, Baylor College of Medicine, Houston, TX 77030, USA
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96
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Green KJ, Böhringer M, Gocken T, Jones JCR. Intermediate filament associated proteins. ADVANCES IN PROTEIN CHEMISTRY 2005; 70:143-202. [PMID: 15837516 DOI: 10.1016/s0065-3233(05)70006-1] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Intermediate filament associated proteins (IFAPs) coordinate interactions between intermediate filaments (IFs) and other cytoskeletal elements and organelles, including membrane-associated junctions such as desmosomes and hemidesmosomes in epithelial cells, costameres in striated muscle, and intercalated discs in cardiac muscle. IFAPs thus serve as critical connecting links in the IF scaffolding that organizes the cytoplasm and confers mechanical stability to cells and tissues. However, in recent years it has become apparent that IFAPs are not limited to structural crosslinkers and bundlers but also include chaperones, enzymes, adapters, and receptors. IF networks can therefore be considered scaffolding upon which associated proteins are organized and regulated to control metabolic activities and maintain cell homeostasis.
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Affiliation(s)
- Kathleen J Green
- Departments of Pathology and Dermatology and R.H. Lurie Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, USA
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97
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Grossmann KS, Grund C, Huelsken J, Behrend M, Erdmann B, Franke WW, Birchmeier W. Requirement of plakophilin 2 for heart morphogenesis and cardiac junction formation. ACTA ACUST UNITED AC 2004; 167:149-60. [PMID: 15479741 PMCID: PMC2172504 DOI: 10.1083/jcb.200402096] [Citation(s) in RCA: 212] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Plakophilins are proteins of the armadillo family that function in embryonic development and in the adult, and when mutated can cause disease. We have ablated the plakophilin 2 gene in mice. The resulting mutant mice exhibit lethal alterations in heart morphogenesis and stability at mid-gestation (E10.5–E11), characterized by reduced trabeculation, disarrayed cytoskeleton, ruptures of cardiac walls, and blood leakage into the pericardiac cavity. In the absence of plakophilin 2, the cytoskeletal linker protein desmoplakin dissociates from the plaques of the adhering junctions that connect the cardiomyocytes and forms granular aggregates in the cytoplasm. By contrast, embryonic epithelia show normal junctions. Thus, we conclude that plakophilin 2 is important for the assembly of junctional proteins and represents an essential morphogenic factor and architectural component of the heart.
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Affiliation(s)
- Katja S Grossmann
- Max Delbrueck Center for Molecular Medicine (MDC), D-13092 Berlin, Germany
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98
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Aho S. Plakin proteins are coordinately cleaved during apoptosis but preferentially through the action of different caspases. Exp Dermatol 2004; 13:700-7. [PMID: 15500642 DOI: 10.1111/j.0906-6705.2004.00217.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
In epithelial cells, cell-cell and cell-matrix junctions, desmosomes and hemidesmosomes, provide anchorage sites for the keratin-intermediate filaments. The plakin proteins desmoplakin (DP), plectin, and periplakin represent intracellular constituents of these adhesion junctions. In staurosporine-treated apoptotic HaCaT cells, DP, plectin, and periplakin became cleaved coordinately with the elimination of keratins 10 and 14, while involucrin, actin, and keratin 18 displayed considerable stability. The caspase inhibitor zVAD-fmk prevented both the cell detachment and protein cleavage, indicating the function of caspases in these events. Closer examination in vitro revealed that while caspases 2 and 4 most efficiently cleaved DP, and plectin served as a target for caspases 3 and 7, periplakin as well as keratins were cleaved by caspase 6. The involvement of multiple caspases in the destruction of epithelial cell integrity ensures the efficient elimination of cytoskeleton, but also provides specificity for selectively targeting individual adhesion molecules.
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Affiliation(s)
- Sirpa Aho
- Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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99
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Red-Horse K, Zhou Y, Genbacev O, Prakobphol A, Foulk R, McMaster M, Fisher SJ. Trophoblast differentiation during embryo implantation and formation of the maternal-fetal interface. J Clin Invest 2004. [DOI: 10.1172/jci200422991] [Citation(s) in RCA: 523] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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100
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Aho S, Li K, Ryoo Y, McGee C, Ishida-Yamamoto A, Uitto J, Klement JF. Periplakin gene targeting reveals a constituent of the cornified cell envelope dispensable for normal mouse development. Mol Cell Biol 2004; 24:6410-8. [PMID: 15226441 PMCID: PMC434234 DOI: 10.1128/mcb.24.14.6410-6418.2004] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The members of the plakin family of proteins serve as epidermal cytolinkers and components of cell-cell and cell-matrix adhesion complexes, i.e., desmosomes and hemidesmosomes, respectively. Periplakin is a recently characterized member of this family. Human and mouse periplakin genomic loci are conserved, and the proteins are highly homologous, suggesting a role for periplakin in vertebrate physiology. In order to evaluate the functional role of periplakin, we generated periplakin null mice through targeted homologous recombination of mouse embryonic stem cells, followed by development of Ppl(-/-) mice. Mice homozygous for the targeted allele were born in the expected Mendelian frequency, developed normally, possessed grossly normal epidermis and hair, and were healthy and fertile. The epidermal barrier appeared to develop normally during fetal days E15.5 to E16.5, and the cornified envelope and desmosomes in the newborn mice were ultrastructurally normal. No compensatory increase in the expression of other epithelial proteins was detected in the neonatal mouse epidermis lacking periplakin. Consequently, the primary role of periplakin may not relate to the physiology of the cornified cell envelope in epidermal keratinocytes but may reside in the challenges, which normal laboratory mice do not encounter.
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Affiliation(s)
- Sirpa Aho
- Department of Dermatology and Cutaneous Biology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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