The Experts below are selected from a list of 348 Experts worldwide ranked by ideXlab platform
Fiona M Watt - One of the best experts on this subject based on the ideXlab platform.
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increased bacterial load and expression of antimicrobial peptides in skin of barrier deficient mice with reduced cancer susceptibility
Journal of Investigative Dermatology, 2016Co-Authors: Ken Natsuga, Sara Cipolat, Fiona M WattAbstract:Mice lacking three epidermal barrier proteins—Envoplakin, periplakin, and involucrin (EPI-/- mice)—have a defective cornified layer, reduced epidermal γδ T cells, and increased dermal CD4+ T cells. They are also resistant to developing skin tumors. The tumor-protective mechanism involves signaling between Rae-1 expressing keratinocytes and the natural killer group 2D receptor on immune cells, which also plays a role in host defenses against infection. Given the emerging link between bacteria and cancer, we investigated whether EPI-/- mice have an altered skin microbiota. The bacterial phyla were similar in wild-type and EPI-/- skin. However, bacteria were threefold more abundant in EPI-/- skin and penetrated deeper into the epidermis. The major epithelial defense mechanism against bacteria is production of antimicrobial proteins (AMPs). EPI-/- skin exhibited enhanced expression of antimicrobial peptides. However, reducing the bacterial load by antibiotic treatment or breeding mice under specific pathogen-free conditions did not reduce AMP expression or alleviate the abnormalities in T-cell populations. We conclude that the atopic characteristics of EPI-/- skin are a consequence of the defective barrier rather than a response to the increased bacterial load. It is therefore unlikely that the increase in skin microbiota contributes directly to the observed cancer resistance.
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Subcellular Distribution of Envoplakin and Periplakin: Insights into Their Role as Precursors of the Epidermal Cornified Envelope
2013Co-Authors: Teresa Dicol, Arto Määttä, Tadashi Karashima, Fiona M WattAbstract:Abstract. Envoplakin and periplakin are two plakins that are precursors of the epidermal cornified envelope. We studied their distribution and interactions by transfection of primary human keratinocytes and other cells. Full-length periplakin localized to desmosomes, the interdesmosomal plasma membrane and intermediate filaments. Full length Envoplakin also localized to desmosomes, but mainly accumulated in nuclear and cytoplasmic aggregates with associated intermediate filaments. The Envoplakin rod domain was required for aggregation and the periplakin rod domain was necessary and sufficient to redistribute Envoplakin to desmosomes and the cytoskeleton, confirming earlier predictions that the proteins can heterodimerize. The linker domain of each protein was required for intermediate filament association. Like the NH 2 terminus of desmoplakin, that of periplakin localized to desmosomes; however, in addition, the periplakin NH 2 terminus accumulated at cell surface microvilli in association with cortical actin. Endogenous periplakin was redistributed from microvilli when keratinocytes were treated with the actin disrupting drug Latrunculin B. We propose that whereas Envoplakin and periplakin can localize independently to desmosomes, the distribution of Envoplakin at the interdesmosomal plasma membrane depends on heterodimerization with periplakin and that the NH 2 terminus of periplakin therefore plays a key role in forming the scaffold on which the cornified envelope is assembled. Key words: Envoplakin • periplakin • desmosomes • cornified envelope • keratinocyte
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JCB: ARTICLE Mice deficient in involucrin, Envoplakin, and periplakin have a defective epidermal barrier
2013Co-Authors: Lisa M Sevilla, Arto Määttä, Karen R Groot, John F Klement, Rachida Nachat, Jouni Uitto, Fiona M WattAbstract:The cornified envelope is assembled from transglutaminase cross-linked proteins and lipids in the outermost epidermal layers and is essential for skin barrier function. Involucrin, Envoplakin, and periplakin form the protein scaffold on which the envelope assembles. To examine their combined function, we generated mice defi cient in all three genes. The triple knockouts have delayed embryonic barrier formation and postnatal hyperkeratosis (abnormal accumulation of cornified cells) resulting from impaired desquamation. Cornified envelopes form but are ultrastructurally abnormal, wit
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Mice deficient in involucrin, Envoplakin, and periplakin have a defective epidermal barrier.
Journal of Cell Biology, 2007Co-Authors: Lisa M Sevilla, Arto Määttä, Karen R Groot, John F Klement, Rachida Nachat, Philippe Djian, Fiona M WattAbstract:The cornified envelope is assembled from transglutaminase cross-linked proteins and lipids in the outermost epidermal layers and is essential for skin barrier function. Involucrin, Envoplakin, and periplakin form the protein scaffold on which the envelope assembles. To examine their combined function, we generated mice deficient in all three genes. The triple knockouts have delayed embryonic barrier formation and postnatal hyperkeratosis (abnormal accumulation of cornified cells) resulting from impaired desquamation. Cornified envelopes form but are ultrastructurally abnormal, with reduced lipid content and decreased mechanical integrity. Expression of proteases is reduced and the protease inhibitor, serpina1b, is highly upregulated, resulting in defective filaggrin processing and delayed degradation of desmoglein 1 and corneodesmosin. There is infiltration of CD4+ T cells and a reduction in resident gammadelta+ T cells, reminiscent of atopic dermatitis. Thus, combined loss of the cornified envelope proteins not only impairs the epidermal barrier, but also changes the composition of T cell subpopulations in the skin.
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mice deficient in involucrin Envoplakin and periplakin have a defective epidermal barrier
Journal of Cell Biology, 2007Co-Authors: Lisa M Sevilla, Arto Määttä, Karen R Groot, John F Klement, Rachida Nachat, Philippe Djian, Fiona M WattAbstract:The cornified envelope is assembled from transglutaminase cross-linked proteins and lipids in the outermost epidermal layers and is essential for skin barrier function. Involucrin, Envoplakin, and periplakin form the protein scaffold on which the envelope assembles. To examine their combined function, we generated mice deficient in all three genes. The triple knockouts have delayed embryonic barrier formation and postnatal hyperkeratosis (abnormal accumulation of cornified cells) resulting from impaired desquamation. Cornified envelopes form but are ultrastructurally abnormal, with reduced lipid content and decreased mechanical integrity. Expression of proteases is reduced and the protease inhibitor, serpina1b, is highly upregulated, resulting in defective filaggrin processing and delayed degradation of desmoglein 1 and corneodesmosin. There is infiltration of CD4+ T cells and a reduction in resident γδ+ T cells, reminiscent of atopic dermatitis. Thus, combined loss of the cornified envelope proteins not only impairs the epidermal barrier, but also changes the composition of T cell subpopulations in the skin.
Arto Määttä - One of the best experts on this subject based on the ideXlab platform.
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functional analysis of periplakin and Envoplakin cytoskeletal linkers and cornified envelope precursor proteins
Methods in Enzymology, 2016Co-Authors: Veronika Boczonadi, Arto MäättäAbstract:Envoplakin and periplakin are the two smallest plakin family cytoskeletal linker proteins that connect intermediate filaments to cellular junctions and other membrane locations. These two plakins have a structural role in the assembly of the cornified envelope (CE), the terminal stage of epidermal differentiation. Analysis of gene-targeted mice lacking both these plakins and the third initial CE scaffold protein, involucrin, demonstrate the importance of the structural integrity of CE for a proper epidermal barrier function. It has emerged that periplakin, which also has a wider tissue distribution than Envoplakin, has additional, independent roles. Periplakin participates in the cytoskeletal organization also in other tissues and interacts with a wide range of membrane-associated proteins such as kazrin and butyrophilin BTN3A1. This review covers methods used to understand periplakin and Envoplakin functions in cell culture models, including siRNA ablation of periplakin expression and the use of tagged protein domain constructs to study localization and interactions. In addition, assays that can be used to analyze CEs and epidermal barrier function in gene-targeted mice are described and discussed.
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functional analysis of periplakin and Envoplakin cytoskeletal linkers and cornified envelope precursor proteins
Methods in Enzymology, 2016Co-Authors: Veronika Boczonadi, Arto MäättäAbstract:Envoplakin and periplakin are the two smallest plakin family cytoskeletal linker proteins that connect intermediate filaments to cellular junctions and other membrane locations. These two plakins have a structural role in the assembly of the cornified envelope (CE), the terminal stage of epidermal differentiation. Analysis of gene-targeted mice lacking both these plakins and the third initial CE scaffold protein, involucrin, demonstrate the importance of the structural integrity of CE for a proper epidermal barrier function. It has emerged that periplakin, which also has a wider tissue distribution than Envoplakin, has additional, independent roles. Periplakin participates in the cytoskeletal organization also in other tissues and interacts with a wide range of membrane-associated proteins such as kazrin and butyrophilin BTN3A1. This review covers methods used to understand periplakin and Envoplakin functions in cell culture models, including siRNA ablation of periplakin expression and the use of tagged protein domain constructs to study localization and interactions. In addition, assays that can be used to analyze CEs and epidermal barrier function in gene-targeted mice are described and discussed.
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Subcellular Distribution of Envoplakin and Periplakin: Insights into Their Role as Precursors of the Epidermal Cornified Envelope
2013Co-Authors: Teresa Dicol, Arto Määttä, Tadashi Karashima, Fiona M WattAbstract:Abstract. Envoplakin and periplakin are two plakins that are precursors of the epidermal cornified envelope. We studied their distribution and interactions by transfection of primary human keratinocytes and other cells. Full-length periplakin localized to desmosomes, the interdesmosomal plasma membrane and intermediate filaments. Full length Envoplakin also localized to desmosomes, but mainly accumulated in nuclear and cytoplasmic aggregates with associated intermediate filaments. The Envoplakin rod domain was required for aggregation and the periplakin rod domain was necessary and sufficient to redistribute Envoplakin to desmosomes and the cytoskeleton, confirming earlier predictions that the proteins can heterodimerize. The linker domain of each protein was required for intermediate filament association. Like the NH 2 terminus of desmoplakin, that of periplakin localized to desmosomes; however, in addition, the periplakin NH 2 terminus accumulated at cell surface microvilli in association with cortical actin. Endogenous periplakin was redistributed from microvilli when keratinocytes were treated with the actin disrupting drug Latrunculin B. We propose that whereas Envoplakin and periplakin can localize independently to desmosomes, the distribution of Envoplakin at the interdesmosomal plasma membrane depends on heterodimerization with periplakin and that the NH 2 terminus of periplakin therefore plays a key role in forming the scaffold on which the cornified envelope is assembled. Key words: Envoplakin • periplakin • desmosomes • cornified envelope • keratinocyte
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JCB: ARTICLE Mice deficient in involucrin, Envoplakin, and periplakin have a defective epidermal barrier
2013Co-Authors: Lisa M Sevilla, Arto Määttä, Karen R Groot, John F Klement, Rachida Nachat, Jouni Uitto, Fiona M WattAbstract:The cornified envelope is assembled from transglutaminase cross-linked proteins and lipids in the outermost epidermal layers and is essential for skin barrier function. Involucrin, Envoplakin, and periplakin form the protein scaffold on which the envelope assembles. To examine their combined function, we generated mice defi cient in all three genes. The triple knockouts have delayed embryonic barrier formation and postnatal hyperkeratosis (abnormal accumulation of cornified cells) resulting from impaired desquamation. Cornified envelopes form but are ultrastructurally abnormal, wit
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mice deficient in involucrin Envoplakin and periplakin have a defective epidermal barrier
Journal of Cell Biology, 2007Co-Authors: Lisa M Sevilla, Arto Määttä, Karen R Groot, John F Klement, Rachida Nachat, Philippe Djian, Fiona M WattAbstract:The cornified envelope is assembled from transglutaminase cross-linked proteins and lipids in the outermost epidermal layers and is essential for skin barrier function. Involucrin, Envoplakin, and periplakin form the protein scaffold on which the envelope assembles. To examine their combined function, we generated mice deficient in all three genes. The triple knockouts have delayed embryonic barrier formation and postnatal hyperkeratosis (abnormal accumulation of cornified cells) resulting from impaired desquamation. Cornified envelopes form but are ultrastructurally abnormal, with reduced lipid content and decreased mechanical integrity. Expression of proteases is reduced and the protease inhibitor, serpina1b, is highly upregulated, resulting in defective filaggrin processing and delayed degradation of desmoglein 1 and corneodesmosin. There is infiltration of CD4+ T cells and a reduction in resident γδ+ T cells, reminiscent of atopic dermatitis. Thus, combined loss of the cornified envelope proteins not only impairs the epidermal barrier, but also changes the composition of T cell subpopulations in the skin.
Martyn Chidgey - One of the best experts on this subject based on the ideXlab platform.
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molecular mechanism of intermediate filament recognition by plakin proteins
Biochimica et Biophysica Acta, 2020Co-Authors: Fiyaz Mohammed, Michael Overduin, Catharine A Trieber, Martyn ChidgeyAbstract:The plakin family of cytolinkers interacts with intermediate filaments (IFs) through plakin repeat domain (PRD) and linker modules. Recent structure/function studies have established the molecular basis of Envoplakin-PRD and periplakin-linker interactions with vimentin. Both plakin modules share a broad basic groove which recognizes acidic rod elements on IFs, a mechanism that is applicable to other plakin family members. This review postulates a universal IF engagement mechanism that illuminates the specific effects of pathogenic mutations associated with diseases including arrhythmogenic right ventricular cardiomyopathy, and reveals how diverse plakin proteins offer tailored IF tethering to ensure stable, dynamic and regulated cellular structures.
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Mechanism of intermediate filament recognition by plakin repeat domains revealed by Envoplakin targeting of vimentin.
Nature communications, 2016Co-Authors: Claudia Fogl, Michael Overduin, Fiyaz Mohammed, Caezar Al-jassar, Mark Jeeves, Timothy J. Knowles, Penelope Rodriguez-zamora, Scott A. White, Elena Odintsova, Martyn ChidgeyAbstract:Plakin proteins form critical connections between cell junctions and the cytoskeleton; their disruption within epithelial and cardiac muscle cells cause skin-blistering diseases and cardiomyopathies. Envoplakin has a single plakin repeat domain (PRD) which recognizes intermediate filaments through an unresolved mechanism. Herein we report the crystal structure of Envoplakin's complete PRD fold, revealing binding determinants within its electropositive binding groove. Four of its five internal repeats recognize negatively charged patches within vimentin via five basic determinants that are identified by nuclear magnetic resonance spectroscopy. Mutations of the Lys1901 or Arg1914 binding determinants delocalize heterodimeric Envoplakin from intracellular vimentin and keratin filaments in cultured cells. Recognition of vimentin is abolished when its residues Asp112 or Asp119 are mutated. The latter slot intermediate filament rods into basic PRD domain grooves through electrosteric complementarity in a widely applicable mechanism. Together this reveals how plakin family members form dynamic linkages with cytoskeletal frameworks.
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Sequence-specific 1H, 13C and 15N backbone resonance assignments of the plakin repeat domain of human Envoplakin
Biomolecular NMR assignments, 2015Co-Authors: Mark Jeeves, Martyn Chidgey, Claudia Fogl, Caezar Al-jassar, Michael OverduinAbstract:The plakin repeat domain is a distinctive hallmark of the plakin superfamily of proteins, which are found within all epithelial tissues. Plakin repeat domains mediate the interactions of these proteins with the cell cytoskeleton and are critical for the maintenance of tissue integrity. Despite their biological importance, no solution state resonance assignments are available for any homologue. Here we report the essentially complete 1H, 13C and 15N backbone chemical shift assignments of the singular 22 kDa plakin repeat domain of human Envoplakin, providing the means to investigate its interactions with ligands including intermediate filaments.
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hinged plakin domains provide specialized degrees of articulation in Envoplakin periplakin and desmoplakin
PLOS ONE, 2013Co-Authors: Caezar Aljassar, Martyn Chidgey, Pau Bernadό, Michael OverduinAbstract:: Envoplakin, periplakin and desmoplakin are cytoskeletal proteins that provide structural integrity within the skin and heart by resisting shear forces. Here we reveal the nature of unique hinges within their plakin domains that provides divergent degrees of flexibility between rigid long and short arms composed of spectrin repeats. The range of mobility of the two arms about the hinge is revealed by applying the ensemble optimization method to small-angle X-ray scattering data. Envoplakin and periplakin adopt 'L' shaped conformations exhibiting a 'helicopter propeller'-like mobility about the hinge. By contrast desmoplakin exhibits essentially unrestricted mobility by 'jack-knifing' about the hinge. Thus the diversity of molecular jointing that can occur about plakin hinges includes 'L' shaped bends, 'U' turns and fully extended 'I' orientations between rigid blocks of spectrin repeats. This establishes specialised hinges in plakin domains as a key source of flexibility that may allow sweeping of cellular spaces during assembly of cellular structures and could impart adaptability, so preventing irreversible damage to desmosomes and the cell cytoskeleton upon exposure to mechanical stress.
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hinged plakin domains provide specialized degrees of articulation in Envoplakin periplakin and desmoplakin
PLOS ONE, 2013Co-Authors: Caezar Aljassar, Martyn Chidgey, Pau Bernadό, Michael OverduinAbstract:: Envoplakin, periplakin and desmoplakin are cytoskeletal proteins that provide structural integrity within the skin and heart by resisting shear forces. Here we reveal the nature of unique hinges within their plakin domains that provides divergent degrees of flexibility between rigid long and short arms composed of spectrin repeats. The range of mobility of the two arms about the hinge is revealed by applying the ensemble optimization method to small-angle X-ray scattering data. Envoplakin and periplakin adopt 'L' shaped conformations exhibiting a 'helicopter propeller'-like mobility about the hinge. By contrast desmoplakin exhibits essentially unrestricted mobility by 'jack-knifing' about the hinge. Thus the diversity of molecular jointing that can occur about plakin hinges includes 'L' shaped bends, 'U' turns and fully extended 'I' orientations between rigid blocks of spectrin repeats. This establishes specialised hinges in plakin domains as a key source of flexibility that may allow sweeping of cellular spaces during assembly of cellular structures and could impart adaptability, so preventing irreversible damage to desmosomes and the cell cytoskeleton upon exposure to mechanical stress.
Christiana Ruhrberg - One of the best experts on this subject based on the ideXlab platform.
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structure and regulation of the Envoplakin gene
Journal of Biological Chemistry, 2000Co-Authors: Arto Määttä, Christiana Ruhrberg, Fiona M WattAbstract:Abstract Envoplakin, a member of the plakin family of proteins, is a component of desmosomes and the epidermal cornified envelope. To understand how Envoplakin expression is regulated, we have analyzed the structure of the mouse Envoplakin gene and characterized the promoters of both the human and mouse genes. The mouse gene consists of 22 exons and maps to chromosome 11E1, syntenic to the location of the human gene on 17q25. The exon-intron structure of the mouse Envoplakin gene is common to all members of the plakin family: the N-terminal protein domain is encoded by 21 small exons, and the central rod domain and the C-terminal globular domain are coded by a single large exon. The C terminus shows the highest sequence conservation between mouse and human Envoplakins and between Envoplakin and the other family members. The N terminus is also conserved, with sequence homology extending to Drosophila Kakapo. A region between nucleotides −101 and 288 was necessary for promoter activity in transiently transfected primary keratinocytes. This region is highly conserved between the human and mouse genes and contains at least two different positively acting elements identified by site-directed mutagenesis and electrophoretic mobility shift assays. Mutation of a GC box binding Sp1 and Sp3 proteins or a combined E box and Kruppel-like element interacting with unidentified nuclear proteins virtually abolished promoter activity. 600 base pairs of the mouse upstream sequence was sufficient to drive expression of a β-galactosidase reporter gene in the suprabasal layers of epidermis, esophagus, and forestomach of transgenic mice. Thus, we have identified a regulatory region in the Envoplakin gene that can account for the expression pattern of the endogenous protein in stratified squamous epithelia.
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Envoplakin a possible candidate gene for focal neppk esophageal cancer toc the integration of genetic and physical maps of the toc region on 17q25
Genomics, 1999Co-Authors: Joanna M. Risk, H. S. Mills, Christiana Ruhrberg, Fiona M Watt, K E Evans, Hans Christian Hennies, T Di Colandrea, Anthony Ellis, D T Bishop, Nigel K SpurrAbstract:Focal nonepidermolytic palmoplantar keratoderma (NEPPK), or tylosis, is an autosomal, dominantly inherited disorder of the skin that manifests as focal thickening of the palmar and plantar surfaces. In three families studied, the skin disorder cosegregates with esophageal cancer and oral lesions. New haplotype analysis, presented here, places the tylosis esophageal cancer (TOC) locus between D17S1839 and D17S785. Envoplakin (EVPL) is a protein component of desmosomes and the cornified envelope that is expressed in epidermal and esophageal keratinocytes and has been localized to the TOC region. Mutation analysis of EVPL in the three affected families failed to show tylosis-specific mutations, and haplotype analysis of three intragenic sequence polymorphisms of the EVPL gene placed it proximal to D17S1839. Confirmation of the exclusion of EVPL as the TOC gene by location was obtained by integration of the genetic and physical mapping data using radiation hybrid, YAC, BAC, and PAC clones. This new physical map will allow further identification of candidate genes underlying NEPPK associated with esophageal cancer, which may also be implicated in the development of sporadic squamous cell esophageal carcinoma and Barrett's adenocarcinoma.
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periplakin a novel component of cornified envelopes and desmosomes that belongs to the plakin family and forms complexes with Envoplakin
Journal of Cell Biology, 1997Co-Authors: Christiana Ruhrberg, M Nasser A Hajibagheri, David A. D. Parry, Fiona M WattAbstract:The cornified envelope is a layer of transglutaminase cross-linked protein that is assembled under the plasma membrane of keratinocytes in the outermost layers of the epidermis. We have determined the cDNA sequence of one of the proteins that becomes incorporated into the cornified envelope of cultured epidermal keratinocytes, a protein with an apparent molecular mass of 195 kD that is encoded by a mRNA with an estimated size of 6.3 kb. The protein is expressed in keratinizing and nonkeratinizing stratified squamous epithelia and in a number of other epithelia. Expression of the protein is upregulated during the terminal differentiation of epidermal keratinocytes in vivo and in culture. Immunogold electron microscopy was used to demonstrate an association of the 195-kD protein with the desmosomal plaque and with keratin filaments in the differentiated layers of the epidermis. Sequence analysis showed that the 195-kD protein is a member of the plakin family of proteins, to which Envoplakin, desmoplakin, bullous pemphigoid antigen 1, and plectin belong. Envoplakin and the 195-kD protein coimmunoprecipitate. Analysis of their rod domain sequences suggests that the formation of both homodimers and heterodimers would be energetically favorable. Confocal immunofluorescent microscopy of cultured epidermal keratinocytes revealed that Envoplakin and the 195-kD protein form a network radiating from desmosomes, and we speculate that the two proteins may provide a scaffolding onto which the cornified envelope is assembled. We propose to name the 195-kD protein periplakin.
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chromosomal localisation of the human Envoplakin gene evpl to the region of the tylosis oesophageal cancer gene tocg on 17q25
Genomics, 1996Co-Authors: Christiana Ruhrberg, Jill Williamson, Denise Sheer, Fiona M WattAbstract:Envoplakin is a membrane-associated precursor of the epidermal cornified envelope. Envoplakin is homologous to desmoplakin I and desmoplakin II (DPI/ II), bullous pemphigoid antigen 1 (BPAG1), and plectin and is proposed to link desmosomes and keratin filaments to the cornified envelope. We describe the isolation of cosmids and yeast artificial chromosomes containing the complete human Envoplakin gene (EVPL) and show, by analysis of somatic cell hybrids and chromosomal in situ hybridisation, that the Envoplakin gene, unlike the genes encoding BPAG1 and DPI/III, maps to 17q25 and is physically linked to D17S1603. This sequence-tagged site segregates with the autosomal dominant human disease focal nonepidermolytic palmoplantar keratosis (NEPKK; ''tylosis''), which is associated with an increased risk of oesophageal cancer. The chromosomal localisation of the Envoplakin gene, the homology of the encoded protein to keratin-binding proteins, and its expression in epidermal and oesophageal keratinocytes all raise the possibility that loss of Envoplakin function could be responsible for this form of palmoplantar keratoderma. (C) 1996 Academic Press, Inc.
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Envoplakin a novel precursor of the cornified envelope that has homology to desmoplakin
Journal of Cell Biology, 1996Co-Authors: Christiana Ruhrberg, M Nasser A Hajibagheri, Marcia Simon, Thomas P Dooley, Fiona M WattAbstract:The cornified envelope is a layer of transglutaminase cross-linked protein that is deposited under the plasma membrane of keratinocytes in the outermost layers of the epidermis. We present the sequence of one of the cornified envelope precursors, a protein with an apparent molecular mass of 210 kD. The 210-kD protein is translated from a 6.5-kb mRNA that is transcribed from a single copy gene. The mRNA was upregulated during suspension-induced terminal differentiation of cultured human keratinocytes. Like other envelope precursors, the 210-kD protein became insoluble in SDS and beta-mercaptoethanol on activation of transglutaminases in cultured keratinocytes. The protein was expressed in keratinizing and nonkeratinizing stratified squamous epithelia, but not in simple epithelia or nonepithelial cells. Immunofluorescence staining showed that in epidermal keratinocytes, both in vivo and in culture, the protein was upregulated during terminal differentiation and partially colocalized with desmosomal proteins. Immunogold EM confirmed the colocalization of the 210-kD protein and desmoplakin at desmosomes and on keratin filaments throughout the differentiated layers of the epidermis. Sequence analysis showed that the 210-kD protein is homologous to the keratin-binding proteins desmoplakin, bullous pemphigoid antigen 1, and plectin. These data suggest that the 210-kD protein may link the cornified envelope to desmosomes and keratin filaments. We propose that the 210-kD protein be named "Envoplakin."
Ernst Reichmann - One of the best experts on this subject based on the ideXlab platform.
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human eccrine sweat gland cells can reconstitute a stratified epidermis
Journal of Investigative Dermatology, 2010Co-Authors: Thomas Biedermann, Luca Pontiggia, Sophie Bottcherhaberzeth, Sasha J Tharakan, Erik Braziulis, Clemens Schiestl, Martin Meuli, Ernst ReichmannAbstract:Eccrine sweat glands are generally considered to be a possible epidermal stem cell source. Here we compared the multilayered epithelia formed by epidermal keratinocytes and those formed by eccrine sweat gland cells. We demonstrated both in vitro and in vivo the capability of human eccrine sweat gland cells to form a stratified interfollicular epidermis substitute on collagen hydrogels. This is substantiated by the following findings: (1) a stratified epidermis consisting of 10–12 cell layers is formed by sweat gland cells; (2) a distinct stratum corneum develops and is maintained after transplantation onto immuno-incompetent rats; (3) proteins such as filaggrin, loricrin, involucrin, Envoplakin, periplakin, and transglutaminases I and III match with the pattern of the normal human skin; (4) junctional complexes and hemidesmosomes are readily and regularly established; (5) cell proliferation in the basal layer reaches homeostatic levels; (6) the sweat gland-derived epidermis is anchored by hemidesmosomes within a well-developed basal lamina; and (7) palmo-plantar or mucosal markers are not expressed in the sweat gland-derived epidermis. These data suggest that human eccrine sweat glands are an additional source of keratinocytes that can generate a stratified epidermis. Our findings raise the question of the extent to which the human skin is repaired and/or permanently renewed by eccrine sweat gland cells.