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Xu R, He S, Ma D, Liang R, Luo Q, Song G. Plectin Downregulation Inhibits Migration and Suppresses Epithelial Mesenchymal Transformation of Hepatocellular Carcinoma Cells via ERK1/2 Signaling. Int J Mol Sci 2022; 24:ijms24010073. [PMID: 36613521 PMCID: PMC9820339 DOI: 10.3390/ijms24010073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Revised: 12/10/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022] Open
Abstract
Plectin, as a cytoskeleton-related protein, is involved in various physiological and pathological processes of many cell types. Studies have found that plectin affects cancer cell invasion and metastasis, but the exact mechanism is not fully understood. In this study, we aim to investigate the role of plectin in the migration of hepatocellular carcinoma (HCC) cells and explore its relevant molecular mechanism. Herein, we found that the expression of plectin in HCC tissue and cells was significantly increased compared with normal liver tissue and cells. After downregulation of plectin, the migration ability of HCC cells was significantly lower than that of the control group. Moreover, the expression of E-cadherin was upregulated and the expression of N-cadherin and vimentin was downregulated, suggesting that plectin downregulation suppresses epithelial mesenchymal transformation (EMT) of HCC cells. Mechanically, we found that plectin downregulation repressed the extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation. Activation of ERK1/2 recovered the plectin downregulation-inhibited migration and EMT of HCC cells. Taken together, our results demonstrate that downregulation of plectin inhibits HCC cell migration and EMT through ERK1/2 signaling, which provides a novel prognostic biomarker and potential therapeutic target for HCC.
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Affiliation(s)
| | | | | | | | - Qing Luo
- Correspondence: (Q.L.); (G.S.); Tel.: +86-23-6510-2507 (Q.L. & G.S.)
| | - Guanbin Song
- Correspondence: (Q.L.); (G.S.); Tel.: +86-23-6510-2507 (Q.L. & G.S.)
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Assessment of the Soft-Tissue Seal at the Interface between the Base of the Fixed Denture Pontic and the Oral Mucosa. MATERIALS 2021; 14:ma14143997. [PMID: 34300915 PMCID: PMC8306894 DOI: 10.3390/ma14143997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 07/12/2021] [Accepted: 07/13/2021] [Indexed: 11/18/2022]
Abstract
Fixed dentures (bridges) are often selected as a treatment option for a defective prosthesis. In this study, we assess the contact condition between the base of the pontic and oral mucosa, and examine the effect of prosthetic preparation and material biocompatibility. The molars were removed and replaced with experimental implants with a free-end type bridge superstructure after one week. In Experiment 1, we assessed different types of prosthetic pre-treatment: (1) the untreated control group (Con: mucosa recovering from the tooth extraction); (2) the laser irradiation group (Las: mucosa recovering after the damage caused by a CO2 laser); and (3) the tooth extraction group (Ext: mucosa recovering immediately after the teeth extraction). In Experiment 2, five materials (titanium, zirconia, porcelain, gold-platinum alloy, and self-curing resin) were placed at the base of the bridge pontic. Four weeks after the placement of the bridge, the mucosa adjacent to the pontic base was histologically analyzed. In Experiment 1, the Con and Las groups exhibited no formation of an epithelial sealing structure on the pontic base. In the Ext group, adherent epithelium was observed. In Experiment 2, the sealing properties at the pontic interface were superior for titanium and the zirconia compared with those made of porcelain or gold-platinum alloy. In the resin group, a clear delay in epithelial healing was observed.
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Atsuta I, Ayukawa Y, Furuhashi A, Narimatsu I, Kondo R, Oshiro W, Koyano K. Epithelial sealing effectiveness against titanium or zirconia implants surface. J Biomed Mater Res A 2019; 107:1379-1385. [PMID: 30724473 DOI: 10.1002/jbm.a.36651] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 01/29/2019] [Indexed: 11/09/2022]
Abstract
The aims of implant treatment now involve not only restoration of mastication function, but also recovery of esthetics. Currently, zirconia is widely used as an esthetic material for implant abutment. Therefore, it is very important to understand the efficacy of zirconia for epithelial sealing as an implant material. We compared the effects of materials on the sealing of the peri-implant epithelium (PIE) to titanium (Ti) or zirconia (Zr) implants, for application to clinical work. Maxillary first molars were extracted from rats and replaced with Ti or Zr implants. The sealing of the PIE to the implants was evaluated with immunohistochemistry observation and HRP analysis. The morphological and functional changes in rat oral epithelial cells (OECs) cultured on Ti or Zr plates were also evaluated. After 4 weeks, the PIE on the Ti and Zr implants showed similar structures. The Zr implants appeared to form a weak epithelial seal at the tissue-implant interface, and exhibited markedly less adhesive structures than the Ti implants under electron microscopic observation. In the in vitro experiments, decreased expression levels of adhesion proteins were observed in OECs cultured on Zr plates compared with those cultured on Ti plates. In addition, the cell adherence on Zr plates was reduced, while the cell migration was low on Ti plates. Zr is a better choice for an esthetic implant material, but needs further improvement for integration with the epithelial wound healing process around a dental implant. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2019.
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Affiliation(s)
- Ikiru Atsuta
- Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Yasunori Ayukawa
- Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Akihiro Furuhashi
- Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Ikue Narimatsu
- Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Ryosuke Kondo
- Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Wakana Oshiro
- Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Kiyoshi Koyano
- Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
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Gilbert S, Loranger A, Omary MB, Marceau N. Keratin impact on PKCδ- and ASMase-mediated regulation of hepatocyte lipid raft size - implication for FasR-associated apoptosis. J Cell Sci 2016; 129:3262-73. [PMID: 27422101 DOI: 10.1242/jcs.171124] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 07/13/2016] [Indexed: 11/20/2022] Open
Abstract
Keratins are epithelial cell intermediate filament (IF) proteins that are expressed as pairs in a cell-differentiation-regulated manner. Hepatocytes express the keratin 8 and 18 pair (denoted K8/K18) of IFs, and a loss of K8 or K18, as in K8-null mice, leads to degradation of the keratin partner. We have previously reported that a K8/K18 loss in hepatocytes leads to altered cell surface lipid raft distribution and more efficient Fas receptor (FasR, also known as TNFRSF6)-mediated apoptosis. We demonstrate here that the absence of K8 or transgenic expression of the K8 G62C mutant in mouse hepatocytes reduces lipid raft size. Mechanistically, we find that the lipid raft size is dependent on acid sphingomyelinase (ASMase, also known as SMPD1) enzyme activity, which is reduced in absence of K8/K18. Notably, the reduction of ASMase activity appears to be caused by a less efficient redistribution of surface membrane PKCδ toward lysosomes. Moreover, we delineate the lipid raft volume range that is required for an optimal FasR-mediated apoptosis. Hence, K8/K18-dependent PKCδ- and ASMase-mediated modulation of lipid raft size can explain the more prominent FasR-mediated signaling resulting from K8/K18 loss. The fine-tuning of ASMase-mediated regulation of lipid rafts might provide a therapeutic target for death-receptor-related liver diseases.
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Affiliation(s)
- Stéphane Gilbert
- Centre de recherche sur le cancer de l'Université Laval and Centre de recherche du CHU de Québec (HDQ), Québec, Canada G1R 2J6
| | - Anne Loranger
- Centre de recherche sur le cancer de l'Université Laval and Centre de recherche du CHU de Québec (HDQ), Québec, Canada G1R 2J6
| | - M Bishr Omary
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Normand Marceau
- Centre de recherche sur le cancer de l'Université Laval and Centre de recherche du CHU de Québec (HDQ), Québec, Canada G1R 2J6
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Rezniczek GA, Winter L, Walko G, Wiche G. Functional and Genetic Analysis of Plectin in Skin and Muscle. Methods Enzymol 2015; 569:235-59. [PMID: 26778562 DOI: 10.1016/bs.mie.2015.05.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Plectin is a large cytoskeletal linker protein with a multitude of functions affecting various cellular processes. It is expressed as several different isoforms from a highly complex gene. Both, this transcript diversity (mainly caused by short 5'-sequences contained in alternative first exons) and the size (>500 kDa) of the resulting proteins, present considerable challenges to plectin researchers. In this chapter, we will consider these problems and offer advice on how to tackle them best. As plectin has been studied most extensively in skin and muscle, we will focus on these types of tissues and describe some selected methods in detail. Foremost, however, we aim to give the readers some good pointers to available tools and into the existing literature.
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Affiliation(s)
- Günther A Rezniczek
- Department of Obstetrics & Gynecology, Marien Hospital Herne, Ruhr-Universität Bochum, Herne, Germany
| | - Lilli Winter
- Institute of Neuropathology, University Hospital Erlangen, Erlangen, Germany
| | - Gernot Walko
- Centre for Stem Cells & Regenerative Medicine, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - Gerhard Wiche
- Department of Biochemistry & Cell Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria.
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Wiche G, Osmanagic-Myers S, Castañón MJ. Networking and anchoring through plectin: a key to IF functionality and mechanotransduction. Curr Opin Cell Biol 2014; 32:21-9. [PMID: 25460778 DOI: 10.1016/j.ceb.2014.10.002] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 09/29/2014] [Accepted: 10/07/2014] [Indexed: 10/25/2022]
Abstract
Intermediate filaments (IFs) are involved in multiple cellular processes that are essential for the maintenance of cell and tissue integrity as well as response and adaption to stress. Mainly through pathological manifestations in patients and the analysis of genetic mouse models, it became evident that cytolinker proteins of the plakin protein family are essential for many of the functions ascribed to IFs. As discussed in this review, one of them, plectin, affects the assembly properties, interaction potential, compartmentalization, and linkage properties of IFs, making it to a key player for IF functionality. The far reaching consequences of IFs not being well-connected for skin and muscular integrity, migration, and mechanotransduction are highlighted.
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Affiliation(s)
- Gerhard Wiche
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria.
| | - Selma Osmanagic-Myers
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria; Department of Medical Biochemistry, Medical University of Vienna, Vienna, Austria
| | - Maria J Castañón
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
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Leube RE, Moch M, Kölsch A, Windoffer R. "Panta rhei": Perpetual cycling of the keratin cytoskeleton. BIOARCHITECTURE 2014; 1:39-44. [PMID: 21866261 DOI: 10.4161/bioa.1.1.14815] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 01/12/2011] [Accepted: 01/12/2011] [Indexed: 01/13/2023]
Abstract
The filamentous cytoskeletal systems fulfil seemingly incompatible functions by maintaining a stable scaffolding to ensure tissue integrity and simultaneously facilitating rapid adaptation to intracellular processes and environmental stimuli. This paradox is particularly obvious for the abundant keratin intermediate filaments in epithelial tissues. The epidermal keratin cytoskeleton, for example, supports the protective and selective barrier function of the skin while enabling rapid growth and remodelling in response to physical, chemical and microbial challenges. We propose that these dynamic properties are linked to the perpetual re-cycling of keratin intermediate filaments that we observe in cultured cells. This cycle of assembly and disassembly is independent of protein biosynthesis and consists of distinct, temporally and spatially defined steps. In this way, the keratin cytoskeleton remains in constant motion but stays intact and is also able to restructure rapidly in response to specific regulatory cues as is needed, e.g., during division, differentiation and wound healing.
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Affiliation(s)
- Rudolf E Leube
- Institute of Molecular and Cellular Anatomy; RWTH Aachen University; Aachen, Germany
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Mihailovska E, Raith M, Valencia RG, Fischer I, Al Banchaabouchi M, Herbst R, Wiche G. Neuromuscular synapse integrity requires linkage of acetylcholine receptors to postsynaptic intermediate filament networks via rapsyn-plectin 1f complexes. Mol Biol Cell 2014; 25:4130-49. [PMID: 25318670 PMCID: PMC4263455 DOI: 10.1091/mbc.e14-06-1174] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
P1f, a specific isoform of the cytolinker protein plectin, bridges AChRs to the desmin IF network of myofibers via direct interaction with the AChR-scaffolding protein rapsyn. P1f-mediated IF linkage is crucial for the formation and maintenance of AChR clusters, postsynaptic organization of the NMJ, and body locomotion. Mutations in the cytolinker protein plectin lead to grossly distorted morphology of neuromuscular junctions (NMJs) in patients suffering from epidermolysis bullosa simplex (EBS)-muscular dystrophy (MS) with myasthenic syndrome (MyS). Here we investigated whether plectin contributes to the structural integrity of NMJs by linking them to the postsynaptic intermediate filament (IF) network. Live imaging of acetylcholine receptors (AChRs) in cultured myotubes differentiated ex vivo from immortalized plectin-deficient myoblasts revealed them to be highly mobile and unable to coalesce into stable clusters, in contrast to wild-type cells. We found plectin isoform 1f (P1f) to bridge AChRs and IFs via direct interaction with the AChR-scaffolding protein rapsyn in an isoform-specific manner; forced expression of P1f in plectin-deficient cells rescued both compromised AChR clustering and IF network anchoring. In conditional plectin knockout mice with gene disruption in muscle precursor/satellite cells (Pax7-Cre/cKO), uncoupling of AChRs from IFs was shown to lead to loss of postsynaptic membrane infoldings and disorganization of the NMJ microenvironment, including its invasion by microtubules. In their phenotypic behavior, mutant mice closely mimicked EBS-MD-MyS patients, including impaired body balance, severe muscle weakness, and reduced life span. Our study demonstrates that linkage to desmin IF networks via plectin is crucial for formation and maintenance of AChR clusters, postsynaptic NMJ organization, and body locomotion.
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Affiliation(s)
- Eva Mihailovska
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | - Marianne Raith
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | - Rocio G Valencia
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | - Irmgard Fischer
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | - Mumna Al Banchaabouchi
- Preclinical Phenotyping Facility, Campus Science Support Facilities, 1030 Vienna, Austria
| | - Ruth Herbst
- Center for Brain Research and Institute of Immunology, Medical University of Vienna, 1030 Vienna, Austria
| | - Gerhard Wiche
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
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Atsuta I, Ayukawa Y, Furuhashi A, Ogino Y, Moriyama Y, Tsukiyama Y, Koyano K. In vivo and in vitro studies of epithelial cell behavior around titanium implants with machined and rough surfaces. Clin Implant Dent Relat Res 2014; 16:772-81. [PMID: 23448501 DOI: 10.1111/cid.12043] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND The surface roughness of a dental implant affects the epithelial wound healing process and may significantly enhance implant prognosis. PURPOSE We explored the influence of surface roughness on peri-implant epithelium (PIE) sealing and down-growth by comparing machine-surfaced (Ms) and rough-surfaced (Rs) implants. MATERIALS AND METHODS (1) Maxillary first molars were extracted from rats and replaced with Ms or Rs implants. (2) We also compared changes in the morphology of cultured rat oral epithelial cells (OECs) grown on Ms or Rs titanium (Ti) plates. RESULTS (1) After 4 weeks, the PIE around Ms and Rs implants showed a similar structure to junctional epithelium (JE). At 16 weeks, Rs implants appeared to form a weak epithelial seal at the tissue-implant interface and exhibited markedly less PIE down-growth than Ms implants but was deeper than that observed in natural teeth. (2) We observed less expression of adhesion proteins in OECs cultured on Rs plates than in cells grown on Ms plates. Additionally, cell adherence, migration, and proliferation on Rs plates were lower, whereas apoptosis was reduced on Ms plates. CONCLUSION Ms implants are a better choice for integration with an epithelial wound healing process.
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Affiliation(s)
- Ikiru Atsuta
- Section of Implant and Rehabilitative Dentistry, Division of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, Fukuoka, Japan; Center for Craniofacial Molecular Biology, University of Southern California School of Dentistry, Los Angeles, California, USA
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Atsuta I, Ayukawa Y, Yamaza T, Furuhashi A, Koyano K. The role of phosphoinositide 3-kinase in adhesion of oral epithelial cells to titanium. Arch Oral Biol 2013; 58:1696-708. [PMID: 24112737 DOI: 10.1016/j.archoralbio.2013.07.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 07/23/2013] [Accepted: 07/28/2013] [Indexed: 12/24/2022]
Abstract
BACKGROUND Oral epithelial cells (OECs) adhesion to titanium may improve the success rate of implant restoration. PURPOSE We investigated the mechanism by which OECs adhere to titanium dental implants. MATERIALS AND METHODS (1) After culturing rat OECs on titanium plates (Ti) or culture dishes in the presence or absence of a phosphoinositide 3-kinase (PI3K) activator or inhibitors and/or growth factors, and OEC morphology under these conditions were analyzed. (2) Right maxillary first molars were extracted and replaced with experimental implants. The rats were treated with or without growth factors. RESULTS (1) Cell adherence was lower of OECs on Ti than in those on culture dishes, as were the levels of integrin β4 and the continuity of F-actin structures. After PI3K inhibition, markedly reducing adherence to both substrates. In contrast, PI3K activation with activator or insulin-like growth factor restored the OEC adherence and the expression of adhesion molecules on Ti to the levels seen in OECs cultured on dishes. Cell migration was inhibited by PI3K activation. (2) High expression of integrin β4 was observed in the peri-implant epithelia of PI3K-activated rats. CONCLUSION These findings suggest that PI3K plays an important role in the adhesion of OECs to Ti.
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Affiliation(s)
- Ikiru Atsuta
- Section of Implant and Rehabilitative Dentistry, Devision of Oral Rehabilitation, Faculty of Dental Science, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan; Center for Craniofacial Molecular Biology, University of Southern California School of Dentistry, Los Angeles, CA 90033, USA.
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Vannier C, Pesty A, San-Roman MJ, Schmidt AA. The Bin/amphiphysin/Rvs (BAR) domain protein endophilin B2 interacts with plectin and controls perinuclear cytoskeletal architecture. J Biol Chem 2013; 288:27619-27637. [PMID: 23921385 DOI: 10.1074/jbc.m113.485482] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Proteins of the Bin/amphiphysin/Rvs (BAR) domain superfamily are essential in controlling the shape and dynamics of intracellular membranes. Here, we present evidence for the unconventional function of a member of the endophilin family of BAR and Src homology 3 domain-containing proteins, namely endophilin B2, in the perinuclear organization of intermediate filaments. Using mass spectrometry analysis based on capturing endophilin B2 partners in in situ pre-established complexes in cells, we unravel the interaction of endophilin B2 with plectin 1, a variant of the cytoskeleton linker protein plectin as well as with vimentin. Endophilin B2 directly binds the N-terminal region of plectin 1 via Src homology 3-mediated interaction and vimentin indirectly via plectin-mediated interaction. The relevance of these interactions is strengthened by the selective and drastic reorganization of vimentin around nuclei upon overexpression of endophilin B2 and by the extensive colocalization of both proteins in a meshwork of perinuclear filamentous structures. By generating mutants of the endophilin B2 BAR domain, we show that this phenotype requires the BAR-mediated membrane binding activity of endophilin B2. Plectin 1 or endophilin B2 knockdown using RNA interference disturbed the perinuclear organization of vimentin. Altogether, these data suggest that the endophilin B2-plectin 1 complex functions as a membrane-anchoring device organizing and stabilizing the perinuclear network of vimentin filaments. Finally, we present evidence for the involvement of endophilin B2 and plectin 1 in nuclear positioning in individual cells. This points to the potential importance of the endophilin B2-plectin complex in the biological functions depending on nuclear migration and positioning.
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Affiliation(s)
- Christian Vannier
- From CNRS, UMR7592, Institut Jacques Monod, Université Paris Diderot, Sorbonne Paris Cité, 15 Rue Hélène Brion, F-75205 Paris Cedex 13, France
| | - Arlette Pesty
- From CNRS, UMR7592, Institut Jacques Monod, Université Paris Diderot, Sorbonne Paris Cité, 15 Rue Hélène Brion, F-75205 Paris Cedex 13, France
| | - Mabel Jouve San-Roman
- From CNRS, UMR7592, Institut Jacques Monod, Université Paris Diderot, Sorbonne Paris Cité, 15 Rue Hélène Brion, F-75205 Paris Cedex 13, France
| | - Anne A Schmidt
- From CNRS, UMR7592, Institut Jacques Monod, Université Paris Diderot, Sorbonne Paris Cité, 15 Rue Hélène Brion, F-75205 Paris Cedex 13, France.
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Valencia RG, Walko G, Janda L, Novacek J, Mihailovska E, Reipert S, Andrä-Marobela K, Wiche G. Intermediate filament-associated cytolinker plectin 1c destabilizes microtubules in keratinocytes. Mol Biol Cell 2013; 24:768-84. [PMID: 23363598 PMCID: PMC3596248 DOI: 10.1091/mbc.e12-06-0488] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The transition of microtubules (MTs) from an assembled to a disassembled state plays an essential role in several cellular functions. While MT dynamics are often linked to those of actin filaments, little is known about whether intermediate filaments (IFs) have an influence on MT dynamics. We show here that plectin 1c (P1c), one of the multiple isoforms of the IF-associated cytolinker protein plectin, acts as an MT destabilizer. We found that MTs in P1c-deficient (P1c(-/-)) keratinocytes are more resistant toward nocodazole-induced disassembly and display increased acetylation. In addition, live imaging of MTs in P1c(-/-), as well as in plectin-null, cells revealed decreased MT dynamics. Increased MT stability due to P1c deficiency led to changes in cell shape, increased velocity but loss of directionality of migration, smaller-sized focal adhesions, higher glucose uptake, and mitotic spindle aberrations combined with reduced growth rates of cells. On the basis of ex vivo and in vitro experimental approaches, we suggest a mechanism for MT destabilization in which isoform-specific binding of P1c to MTs antagonizes the MT-stabilizing and assembly-promoting function of MT-associated proteins through an inhibitory function exerted by plectin's SH3 domain. Our results open new perspectives on cytolinker-coordinated IF-MT interaction and its physiological significance.
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Affiliation(s)
- Rocio G Valencia
- Max F. Perutz Laboratories, Department of Biochemistry and Cell Biology, University of Vienna, A-1030 Vienna, Austria
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Pieperhoff S, Rickelt S, Heid H, Claycomb WC, Zimbelmann R, Kuhn C, Winter-Simanowski S, Kuhn C, Frey N, Franke WW. The plaque protein myozap identified as a novel major component of adhering junctions in endothelia of the blood and the lymph vascular systems. J Cell Mol Med 2012; 16:1709-19. [PMID: 21992629 PMCID: PMC3822684 DOI: 10.1111/j.1582-4934.2011.01463.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Accepted: 09/07/2011] [Indexed: 01/22/2023] Open
Abstract
Recently the protein myozap, a 54-kD polypeptide which is not a member of any of the known cytoskeletal and junctional protein multigene families, has been identified as a constituent of the plaques of the composite junctions in the intercalated disks connecting the cardiomyocytes of mammalian hearts. Using a set of novel, highly sensitive and specific antibodies we now report that myozap is also a major constituent of the cytoplasmic plaques of the adherens junctions (AJs) connecting the endothelial cells of the mammalian blood and lymph vascular systems, including the desmoplakin-containing complexus adhaerentes of the virgultar cells of lymph node sinus. In light and electron microscopic immunolocalization experiments we show that myozap colocalizes with several proteins of desmosomal plaques as well as with AJ-specific transmembrane molecules, including VE-cadherin. In biochemical analyses, rigorous immunoprecipitation experiments have revealed N-cadherin, desmoplakin, desmoglein-2, plakophilin-2, plakoglobin and plectin as very stably bound complex partners. We conclude that myozap is a general component of cell-cell junctions not only in the myocardium but also in diverse endothelia of the blood and lymph vascular systems of adult mammals, suggesting that this protein not only serves a specific role in the heart but also a broader set of functions in the vessel systems. We also propose to use myozap as an endothelial cell type marker in diagnoses.
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Affiliation(s)
- Sebastian Pieperhoff
- Helmholtz Group Cell Biology, German Cancer Research Center (DKFZ)Heidelberg, Germany
- Centre for Cardiovascular Science, The Queen's Medical Research Institute, University of EdinburghEdinburgh, Scotland, United Kingdom
- Department of Zoology and Faculty of Land and Food Systems, University of British ColumbiaVancouver, Canada
| | - Steffen Rickelt
- Helmholtz Group Cell Biology, German Cancer Research Center (DKFZ)Heidelberg, Germany
- Progen Biotechnik GmbH, HeidelbergGermany
| | - Hans Heid
- Helmholtz Group Cell Biology, German Cancer Research Center (DKFZ)Heidelberg, Germany
| | | | - Ralf Zimbelmann
- Helmholtz Group Cell Biology, German Cancer Research Center (DKFZ)Heidelberg, Germany
| | - Caecilia Kuhn
- Helmholtz Group Cell Biology, German Cancer Research Center (DKFZ)Heidelberg, Germany
- Progen Biotechnik GmbH, HeidelbergGermany
| | | | - Christian Kuhn
- Internal Medicine and Cardiology, Department of Cardiology and Angiology, University Hospital, Schleswig-HolsteinCampus Kiel, Kiel, Germany
| | - Norbert Frey
- Internal Medicine and Cardiology, Department of Cardiology and Angiology, University Hospital, Schleswig-HolsteinCampus Kiel, Kiel, Germany
| | - Werner W Franke
- Helmholtz Group Cell Biology, German Cancer Research Center (DKFZ)Heidelberg, Germany
- Progen Biotechnik GmbH, HeidelbergGermany
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14
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Windoffer R, Beil M, Magin TM, Leube RE. Cytoskeleton in motion: the dynamics of keratin intermediate filaments in epithelia. ACTA ACUST UNITED AC 2012; 194:669-78. [PMID: 21893596 PMCID: PMC3171125 DOI: 10.1083/jcb.201008095] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Epithelia are exposed to multiple forms of stress. Keratin intermediate filaments are abundant in epithelia and form cytoskeletal networks that contribute to cell type–specific functions, such as adhesion, migration, and metabolism. A perpetual keratin filament turnover cycle supports these functions. This multistep process keeps the cytoskeleton in motion, facilitating rapid and protein biosynthesis–independent network remodeling while maintaining an intact network. The current challenge is to unravel the molecular mechanisms underlying the regulation of the keratin cycle in relation to actin and microtubule networks and in the context of epithelial tissue function.
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Affiliation(s)
- Reinhard Windoffer
- Institute of Molecular and Cellular Anatomy, RWTH Aachen University, 52057 Aachen, Germany
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15
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Targeted proteolysis of plectin isoform 1a accounts for hemidesmosome dysfunction in mice mimicking the dominant skin blistering disease EBS-Ogna. PLoS Genet 2011; 7:e1002396. [PMID: 22144912 PMCID: PMC3228830 DOI: 10.1371/journal.pgen.1002396] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 10/10/2011] [Indexed: 01/09/2023] Open
Abstract
Autosomal recessive mutations in the cytolinker protein plectin account for the multisystem disorders epidermolysis bullosa simplex (EBS) associated with muscular dystrophy (EBS-MD), pyloric atresia (EBS-PA), and congenital myasthenia (EBS-CMS). In contrast, a dominant missense mutation leads to the disease EBS-Ogna, manifesting exclusively as skin fragility. We have exploited this trait to study the molecular basis of hemidesmosome failure in EBS-Ogna and to reveal the contribution of plectin to hemidesmosome homeostasis. We generated EBS-Ogna knock-in mice mimicking the human phenotype and show that blistering reflects insufficient protein levels of the hemidesmosome-associated plectin isoform 1a. We found that plectin 1a, in contrast to plectin 1c, the major isoform expressed in epidermal keratinocytes, is proteolytically degraded, supporting the notion that degradation of hemidesmosome-anchored plectin is spatially controlled. Using recombinant proteins, we show that the mutation renders plectin's 190-nm-long coiled-coil rod domain more vulnerable to cleavage by calpains and other proteases activated in the epidermis but not in skeletal muscle. Accordingly, treatment of cultured EBS-Ogna keratinocytes as well as of EBS-Ogna mouse skin with calpain inhibitors resulted in increased plectin 1a protein expression levels. Moreover, we report that plectin's rod domain forms dimeric structures that can further associate laterally into remarkably stable (paracrystalline) polymers. We propose focal self-association of plectin molecules as a novel mechanism contributing to hemidesmosome homeostasis and stabilization. Hemidesmosomes are specialized protein complexes that promote anchorage of the basal keratinocyte cell layer of the epidermis to the underlying dermis. They provide tissue integrity and resistance to mechanical forces. When hemidesmosomes do not function properly, skin blistering ensues in response to mechanical trauma. Plectin is an essential component of hemidesmosomes. Humans carrying recessive mutations in the plectin gene most frequently develop multisystem disorders, where in addition to skin other tissues are also affected. However, there is a unique dominant plectin mutation, which leads to the disease epidermolysis bullosa simplex Ogna (EBS-Ogna), affecting skin exclusively. Because of that, EBS-Ogna is an exceptional system to study the contribution of plectin to hemidesmosome function. We have generated an EBS-Ogna mouse model that mimics the human disease. Using this model, we have learned that selective degradation of hemidesmosome-associated plectin isoform 1a by proteases activated specifically in keratinocytes results in reduced numbers and dysfunction of hemidesmosomes. In contrast, plectin-1c, another plectin isoform expressed in keratinocytes, is not degraded. Moreover, we find that plectin dimers can oligomerize via their long coiled-coil rod domain, a process likely to be instrumental in maintenance of hemidesmosome integrity. These findings highlight the importance of plectin-1a for hemidesmosome function.
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16
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Ghosh D, Yu H, Tan XF, Lim TK, Zubaidah RM, Tan HT, Chung MCM, Lin Q. Identification of key players for colorectal cancer metastasis by iTRAQ quantitative proteomics profiling of isogenic SW480 and SW620 cell lines. J Proteome Res 2011; 10:4373-87. [PMID: 21854069 DOI: 10.1021/pr2005617] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This study compared the whole cell proteome profiles of two isogenic colorectal cancer (CRC) cell lines (primary SW480 cell line and its lymph node metastatic variant SW620), as an in vitro metastatic model, to gain an insight into the molecular events of CRC metastasis. Using iTRAQ (isobaric tags for relative and absolute quantitation) based shotgun proteomics approach, we identified 1140 unique proteins, out of which 147 were found to be significantly altered in the metastatic cell. Ingenuity pathway analysis with those significantly altered proteins, revealed cellular organization and assembly as the top-ranked altered biological function. Differential expression pattern of 6 candidate proteins were validated by Western blot. Among these, the low expression level of β-catenin combined with the up-regulation of CacyBP (Calcyclin binding Protein), a β-catenin degrading protein, in the metastatic cell provided a rational guide for the downstream functional assays. The relative expression pattern of these two proteins was further validated in three other CRC cells by Western blot and quantitative immunofluorescence studies. Overexpression of CacyBP in three different primary CRC cell lines showed significant reduction in adhesion characteristics as well as cellular β-catenin level as confirmed by our experiments, indicating the possible involvement of CacyBP in CRC metastasis. In short, this study demonstrates successful application of a quantitative proteomics approach to identify novel key players for CRC metastasis, which may serve as biomarkers and/or drug targets to improve CRC therapy.
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Affiliation(s)
- Dipanjana Ghosh
- Department of Biological Sciences, National University of Singapore , 14 Science Drive 4, Singapore 117543
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17
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Liu YH, Ho CC, Cheng CC, Chao WT, Pei RJ, Hsu YH, Lai YS. Cytokeratin 18-mediated disorganization of intermediate filaments is induced by degradation of plectin in human liver cells. Biochem Biophys Res Commun 2011; 407:575-80. [DOI: 10.1016/j.bbrc.2011.03.066] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2011] [Accepted: 03/15/2011] [Indexed: 01/02/2023]
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18
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Plectin deficiency on cytoskeletal disorganization and transformation of human liver cells in vitro. Med Mol Morphol 2011; 44:21-6. [DOI: 10.1007/s00795-010-0499-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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19
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Liu YH, Cheng CC, Lai YS, Chao WT, Pei RJ, Hsu YH, Ho CC. Synemin down-regulation in human hepatocellular carcinoma does not destabilize cytoskeletons in vivo. Biochem Biophys Res Commun 2010; 404:488-93. [PMID: 21144834 DOI: 10.1016/j.bbrc.2010.12.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Accepted: 12/02/2010] [Indexed: 11/17/2022]
Abstract
Synemin is a large intermediate filament protein that has been identified in all types of muscle cells. It plays a role in human muscle diseases; however, the role of synemin in tumor cell transformation has rarely been investigated. Because hepatocellular carcinoma cells are morphologically different from normal human hepatocytes, we hypothesized that altered synemin expression and cytoskeletal disorganization might underlie this pleomorphic transformation. To test this hypothesis, we studied synemin expression in hepatocellular carcinoma and liver tissues by immunohistochemistry and immunoblotting. In addition, we analyzed the expression level and organization of all cytoskeletal elements after synemin knock-down in human Chang liver cells. Previously we found that plectin knock-down in human Chang liver cells causes a reduction in cytokeratin 18 expression with effects on intermediate filament disorganization and altered cellular morphology. In this study we also compared the effects of synemin knock-down and plectin knock-down on the cytoskeleton expression and organization. The results revealed that synemin expression was down-regulated in human hepatocellular carcinoma compared with normal liver, which is similar to the plectin expression. Surprisingly, the expression of cytoskeletal elements (cytokeratin 18, actin and tubulin) was not influenced by synemin knock-down in human Chang liver cells. The organization of cytoskeletal networks was also unaltered after synemin knock-down. In conclusion, both plectin and synemin are down-regulated in human hepatocellular carcinoma in vivo and transformed human liver cell in vitro. However, the mechanism of cell transformation caused by synemin knock-down is different from that of plectin knock-down. Plectin, but not synemin, knock-down provoked liver cell transformation via suppressing cytokeratin 18 expression and disrupting intermediate filament networks. Synemin knock-down did not influence the cytoskeleton expression and organization of human Chang liver cells.
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Affiliation(s)
- Yi-Hsiang Liu
- Department of Pathology, Chang Bing Show Chwan Memorial Hospital, Changhua, Taiwan
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20
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Burgstaller G, Gregor M, Winter L, Wiche G. Keeping the vimentin network under control: cell-matrix adhesion-associated plectin 1f affects cell shape and polarity of fibroblasts. Mol Biol Cell 2010; 21:3362-75. [PMID: 20702585 PMCID: PMC2947472 DOI: 10.1091/mbc.e10-02-0094] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Mature focal adhesions and fibrillar adhesions act as anchorage sites for vimentin filaments, with plectin isoform 1f being the crucial linker protein. Plectin serves as a nucleation and assembly center for the de novo formation of vimentin networks. Anchored vimentin creates a resilient cage-like core structure that affects cell shape. Focal adhesions (FAs) located at the ends of actin/myosin-containing contractile stress fibers form tight connections between fibroblasts and their underlying extracellular matrix. We show here that mature FAs and their derivative fibronectin fibril-aligned fibrillar adhesions (FbAs) serve as docking sites for vimentin intermediate filaments (IFs) in a plectin isoform 1f (P1f)-dependent manner. Time-lapse video microscopy revealed that FA-associated P1f captures mobile vimentin filament precursors, which then serve as seeds for de novo IF network formation via end-to-end fusion with other mobile precursors. As a consequence of IF association, the turnover of FAs is reduced. P1f-mediated IF network formation at FbAs creates a resilient cage-like core structure that encases and positions the nucleus while being stably connected to the exterior of the cell. We show that the formation of this structure affects cell shape with consequences for cell polarization.
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Affiliation(s)
- Gerald Burgstaller
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, A-1030 Vienna, Austria
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21
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Bordeleau F, Galarneau L, Gilbert S, Loranger A, Marceau N. Keratin 8/18 modulation of protein kinase C-mediated integrin-dependent adhesion and migration of liver epithelial cells. Mol Biol Cell 2010; 21:1698-713. [PMID: 20357007 PMCID: PMC2869376 DOI: 10.1091/mbc.e09-05-0373] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Hepatocyte and hepatoma cell IFs are made solely of keratins 8/18 (K8/K18). Cell adhesion and migration involve integrin interactions with focal adhesion kinase (FAK) and protein kinase C (PKC). Here we report a new regulatory function for K8/K18 IFs in the PKC-mediated integrin/FAK-dependent adhesion and migration of simple epithelial cells. Keratins are intermediate filament (IF) proteins of epithelial cells, expressed as pairs in a lineage/differentiation manner. Hepatocyte and hepatoma cell IFs are made solely of keratins 8/18 (K8/K18), the hallmark of all simple epithelia. Cell attachment/spreading (adhesion) and migration involve the formation of focal adhesions at sites of integrin interactions with extracellular matrix, actin adaptors such as talin and vinculin, and signaling molecules such as focal adhesion kinase (FAK) and member(s) of the protein kinase C (PKC) family. Here, we identify the novel PKCδ as mediator of the K8/K18 modulation of hepatoma cell adhesion and migration. We also demonstrate a K8/K18-dependent relationship between PKCδ and FAK activation through an integrin/FAK-positive feedback loop, in correlation with a reduced FAK time residency at focal adhesions. Notably, a K8/K18 loss results to a time course modulation of the receptor of activated C-kinase-1, β1-integrin, plectin, PKC, and c-Src complex formation. Although the K8/K18 modulation of hepatocyte adhesion also occurs through a PKC mediation, these differentiated epithelial cells exhibit minimal migrating ability, in link with marked differences in protein partner content and distribution. Together, these results uncover a key regulatory function for K8/K18 IFs in the PKC-mediated integrin/FAK-dependent adhesion and migration of simple epithelial cells.
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Affiliation(s)
- François Bordeleau
- Centre de Recherche en Cancérologie and Département de Médecine de l'Université Laval, and Centre de Recherche du Centre Hospitalier Universitaire de Québec (CRCHUQ), Quebec City, QC, Canada
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22
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Kölsch A, Windoffer R, Leube RE. Actin-dependent dynamics of keratin filament precursors. ACTA ACUST UNITED AC 2009; 66:976-85. [DOI: 10.1002/cm.20395] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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23
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Fuchs P, Zörer M, Reipert S, Rezniczek GA, Propst F, Walko G, Fischer I, Bauer J, Leschnik MW, Lüscher B, Thalhammer JG, Lassmann H, Wiche G. Targeted inactivation of a developmentally regulated neural plectin isoform (plectin 1c) in mice leads to reduced motor nerve conduction velocity. J Biol Chem 2009; 284:26502-9. [PMID: 19625254 PMCID: PMC2785338 DOI: 10.1074/jbc.m109.018150] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 07/08/2009] [Indexed: 12/27/2022] Open
Abstract
Cytolinker proteins stabilize cells mechanically, regulate cytoskeleton dynamics, and provide scaffolds for signaling molecules. For plectin, the prototype of these proteins, an unusual diversity of isoforms has been reported, which show distinct expression patterns, subcellular localizations, and functions. Plectin has been shown to have important functions in skin and muscle, but little is known about its role in neural cells. To address this issue, we generated two knock-out mouse lines, one which was selectively lacking plectin 1c (P1c), the major isoform expressed in neural cells, and another in which plectin was conditionally deleted in neuronal precursor cells. Using isoform-specific antibodies, we found P1c to be expressed late in development and to associate with postsynaptic dendrites of central nervous system neurons, motorneurons of spinal cord, sciatic nerve axons, and Schwann cells. Motor nerve conduction velocity was found significantly reduced in sciatic nerve from P1c-deficient as well as from conditional knock-out mice. This defect was traceable to an increased number of motor nerve fibers with small cross-sectional areas; the thicknesses of axons and of myelin sheaths were unaffected. This is the first report demonstrating an important role of plectin in a major nerve function.
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Affiliation(s)
- Peter Fuchs
- From the Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Michael Zörer
- From the Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Siegfried Reipert
- From the Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Günther A. Rezniczek
- From the Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Friedrich Propst
- From the Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Gernot Walko
- From the Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Irmgard Fischer
- From the Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
| | - Jan Bauer
- the Department of Neuroimmunology, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria
| | - Michael W. Leschnik
- the Clinic for Internal Medicine and Infectious Diseases, University of Veterinary Medicine Vienna, 1210 Vienna, Austria, and
| | - Bernhard Lüscher
- the Division of Biochemistry and Molecular Biology, Medical Faculty of the Rheinisch-Westfaelische Technische Hochschule Aachen University, 52074 Aachen, Germany
| | - Johann G. Thalhammer
- the Clinic for Internal Medicine and Infectious Diseases, University of Veterinary Medicine Vienna, 1210 Vienna, Austria, and
| | - Hans Lassmann
- the Department of Neuroimmunology, Center for Brain Research, Medical University of Vienna, 1090 Vienna, Austria
| | - Gerhard Wiche
- From the Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohr-Gasse 9, 1030 Vienna, Austria
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24
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Kostan J, Gregor M, Walko G, Wiche G. Plectin isoform-dependent regulation of keratin-integrin alpha6beta4 anchorage via Ca2+/calmodulin. J Biol Chem 2009; 284:18525-36. [PMID: 19419971 DOI: 10.1074/jbc.m109.008474] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The detachment of epithelial cells from the basal matrix during wound healing and differentiation of keratinocytes requires the disassembly of the hemidesmosomal multiprotein adhesion complex. Integrin alpha6beta4-plectin interaction plays a major role in the formation of hemidesmosomes, and thus the mechanisms regulating this interaction should be critical also for the disassembly process. Here we show that a particular plectin isoform (1a) interacts with the Ca(2+)-sensing protein calmodulin in a Ca(2+)-dependent manner. As a result of this interaction, binding of the hemidesmosome-associated plectin isoform 1a to integrin beta4 is substantially diminished. Calmodulin-binding inhibits also the interaction of plectin with F-actin. Further, we found that, during Ca(2+)-induced keratinocyte differentiation, plectin 1a is first relocated within the cell and later down-regulated, suggesting that Ca(2+) affects the fate of plectin 1a upon its release from hemidesmosomes. We propose a novel model for the disassembly of hemidesmosomes during keratinocyte differentiation, where both, binding of calmodulin to plectin 1a and phosphorylation of integrin beta4 by protein kinases, are required for disruption of the integrin alpha6beta4-plectin complex.
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Affiliation(s)
- Julius Kostan
- Department of Molecular Cell Biology, Max F. Perutz Laboratories, University of Vienna, Vienna A-1030, Austria
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25
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Winter L, Abrahamsberg C, Wiche G. Plectin isoform 1b mediates mitochondrion-intermediate filament network linkage and controls organelle shape. ACTA ACUST UNITED AC 2008; 181:903-11. [PMID: 18541706 PMCID: PMC2426950 DOI: 10.1083/jcb.200710151] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Plectin is a versatile intermediate filament (IF)–bound cytolinker protein with a variety of differentially spliced isoforms accounting for its multiple functions. One particular isoform, plectin 1b (P1b), remains associated with mitochondria after biochemical fractionation of fibroblasts and cells expressing exogenous P1b. Here, we determined that P1b is inserted into the outer mitochondrial membrane with the exon 1b–encoded N-terminal sequence serving as a mitochondrial targeting and anchoring signal. To study P1b-related mitochondrial functions, we generated mice that selectively lack this isoform but express all others. In primary fibroblasts and myoblasts derived from these mice, we observe a substantial elongation of mitochondrial networks, whereas other mitochondrial properties remain largely unaffected. Normal morphology of mitochondria could be restored by isoform-specific overexpression of P1b in P1b-deficient as well as plectin-null cells. We propose a model where P1b both forms a mitochondrial signaling platform and affects organelle shape and network formation by tethering mitochondria to IFs.
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Affiliation(s)
- Lilli Winter
- Department of Molecular Cell Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
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26
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Wöll S, Windoffer R, Leube RE. p38 MAPK-dependent shaping of the keratin cytoskeleton in cultured cells. ACTA ACUST UNITED AC 2007; 177:795-807. [PMID: 17535969 PMCID: PMC2064280 DOI: 10.1083/jcb.200703174] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Plasticity of the resilient keratin intermediate filament cytoskeleton is an important prerequisite for epithelial tissue homeostasis. Here, the contribution of stress-activated p38 MAPK to keratin network organization was examined in cultured cells. It was observed that phosphorylated p38 colocalized with keratin granules that were rapidly formed in response to orthovanadate. The same p38p recruitment was noted during mitosis, in various stress situations and in cells producing mutant keratins. In all these situations keratin 8 became phosphorylated on S73, a well-known p38 target site. To demonstrate that p38-dependent keratin phosphorylation determines keratin organization, p38 activity was pharmacologically and genetically modulated: up-regulation induced keratin granule formation, whereas down-regulation prevented keratin filament network disassembly. Furthermore, transient p38 inhibition also inhibited keratin filament precursor formation and mutant keratin granule dissolution. Collectively, the rapid and reversible effects of p38 activity on keratin phosphorylation and organization in diverse physiological, stress, and pathological situations identify p38-dependent signalling as a major intermediate filament–regulating pathway.
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Affiliation(s)
- Stefan Wöll
- Department of Anatomy and Cell Biology, Johannes Gutenberg University, 55128 Mainz, Germany
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27
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Rezniczek GA, Konieczny P, Nikolic B, Reipert S, Schneller D, Abrahamsberg C, Davies KE, Winder SJ, Wiche G. Plectin 1f scaffolding at the sarcolemma of dystrophic (mdx) muscle fibers through multiple interactions with beta-dystroglycan. ACTA ACUST UNITED AC 2007; 176:965-77. [PMID: 17389230 PMCID: PMC2064082 DOI: 10.1083/jcb.200604179] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In skeletal muscle, the cytolinker plectin is prominently expressed at Z-disks and the sarcolemma. Alternative splicing of plectin transcripts gives rise to more than eight protein isoforms differing only in small N-terminal sequences (5-180 residues), four of which (plectins 1, 1b, 1d, and 1f) are found at substantial levels in muscle tissue. Using plectin isoform-specific antibodies and isoform expression constructs, we show the differential regulation of plectin isoforms during myotube differentiation and their localization to different compartments of muscle fibers, identifying plectins 1 and 1f as sarcolemma-associated isoforms, whereas plectin 1d localizes exclusively to Z-disks. Coimmunoprecipitation and in vitro binding assays using recombinant protein fragments revealed the direct binding of plectin to dystrophin (utrophin) and beta-dystroglycan, the key components of the dystrophin-glycoprotein complex. We propose a model in which plectin acts as a universal mediator of desmin intermediate filament anchorage at the sarcolemma and Z-disks. It also explains the plectin phenotype observed in dystrophic skeletal muscle of mdx mice and Duchenne muscular dystrophy patients.
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MESH Headings
- Animals
- Cell Compartmentation/physiology
- Cell Differentiation/physiology
- Cells, Cultured
- Cytoskeleton/metabolism
- Cytoskeleton/ultrastructure
- Desmin/metabolism
- Dystroglycans/metabolism
- Humans
- Immunohistochemistry
- Intermediate Filaments/metabolism
- Intermediate Filaments/ultrastructure
- Mice
- Mice, Inbred C57BL
- Mice, Inbred mdx
- Models, Biological
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Skeletal/pathology
- Muscle Fibers, Skeletal/ultrastructure
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Muscle, Skeletal/physiopathology
- Muscular Dystrophy, Animal/genetics
- Muscular Dystrophy, Animal/metabolism
- Muscular Dystrophy, Animal/physiopathology
- Plectin/immunology
- Plectin/metabolism
- Protein Isoforms/immunology
- Protein Isoforms/metabolism
- Rats
- Sarcolemma/metabolism
- Sarcolemma/pathology
- Sarcolemma/ultrastructure
- Utrophin/metabolism
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Affiliation(s)
- Günther A Rezniczek
- Max F. Perutz Laboratories, Department of Molecular Cell Biology, University of Vienna, A-1030 Vienna, Austria
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28
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Fuchs P, Spazierer D, Wiche G. Plectin rodless isoform expression and its detection in mouse brain. Cell Mol Neurobiol 2007; 25:1141-50. [PMID: 16392042 DOI: 10.1007/s10571-005-7826-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2005] [Accepted: 08/08/2005] [Indexed: 11/27/2022]
Abstract
The widely expressed cytolinker protein plectin shows extensive isoform diversity both at the N-terminus and in the central part of the molecule. Judged on mRNA data, plectin variants lacking the central rod domain are expressed at a approximately 20-fold lower level than full-length proteins and their detection on the protein level can be difficult. Here we present data on the expression of plectin rodless isoforms in mouse brain and in rat glioma C6 cells on RNA and protein levels. Our data indicate that among the rodless variants expressed in neuronal tissues, those starting with exon 1c (plectin 1c) seem to be the most prominent ones. In addition, we show that similar to other monoclonal antibodies reported in the literature, the widely used mAb 7A8 recognizes an epitope within plectin's rod domain and therefore is unsuited to detect rodless variants of plectin.
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Affiliation(s)
- Peter Fuchs
- Department of Molecular Cell Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
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29
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Galarneau L, Loranger A, Gilbert S, Marceau N. Keratins modulate hepatic cell adhesion, size and G1/S transition. Exp Cell Res 2006; 313:179-94. [PMID: 17112511 DOI: 10.1016/j.yexcr.2006.10.007] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2006] [Revised: 09/26/2006] [Accepted: 10/02/2006] [Indexed: 12/31/2022]
Abstract
Keratins (Ks) are the intermediate filament (IF) proteins of epithelial cells. Hepatocyte IFs are made solely of keratins 8 and 18 (K8/K18), the hallmark of all simple epithelia. While K8/K18 are essential for maintaining structural integrity, there is accumulating evidence indicating that they also exert non-mechanical functions. We have reported recently that K8/K18-free hepatocytes from K8-null mice are more sensitive to Fas-mediated apoptosis, in line with an increased Fas density at the cell surface and an altered c-Flip regulation of the anti-apoptotic ERK1/2 signaling pathway. In the present study, we show that K8-null hepatocytes attach more rapidly but spread more slowly on a fibronectin substratum and undergo a more efficient G1/S transition than wild-type hepatocytes. Moreover, plectin, an IF associated protein, receptor for activated C kinase 1 (RACK1), a plectin partner, and vinculin, a key component of focal adhesions, distribute differently in spreading K8-null hepatocytes. Cell seeding leads to no differential activation of ERK1/2 in WT versus K8-null hepatocytes, whereas a stronger Akt activation is detected in K8-null hepatocytes. Insulin stimulation also leads to a differential Akt activation, implying altered Akt signaling capacity as a result of the K8/K18 loss. In addition, a delayed autophosphorylation of FAK, a target for integrin beta1 signaling, was obtained in seeding K8-null hepatocytes. These alterations in cell cycle-related events in hepatocytes in primary culture are also found in a K8-knockdown H4-II-E-C3 rat hepatoma cell line. Besides, K8/K18-free cells are smaller and exhibit a reduced rate of protein synthesis. In addition, a distinctive cyclin interplay is observed in these K8/K18-free hepatic cells, namely a more efficient cyclin A-dependent G1/S phase transition. Furthermore, K8 re-expression in these cells, following transfer of a human K8 cDNA, restores proper cell size, spreading and growth. Together, these results suggest new interrelated signaling roles of K8/18 with plectin/RACK1 in the modulation of cell attachment/spreading, size/protein synthesis and G1/S transition.
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Affiliation(s)
- Luc Galarneau
- Centre de Recherche en Cancérologie, Quebec City, QC, Canada G1R 2J6
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Abrahamsberg C, Fuchs P, Osmanagic-Myers S, Fischer I, Propst F, Elbe-Bürger A, Wiche G. Targeted ablation of plectin isoform 1 uncovers role of cytolinker proteins in leukocyte recruitment. Proc Natl Acad Sci U S A 2005; 102:18449-54. [PMID: 16344482 PMCID: PMC1317913 DOI: 10.1073/pnas.0505380102] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Plectin, a typical cytolinker protein, is essential for skin and skeletal muscle integrity. It stabilizes cells mechanically, regulates cytoskeleton dynamics, and serves as a scaffolding platform for signaling molecules. A variety of isoforms expressed in different tissues and cell types account for this versatility. To uncover the role of plectin 1, the major isoform expressed in tissues of mesenchymal origin, against the background of all other variants, we raised plectin isoform 1-specific antibodies and generated isoform-deficient mice. In contrast to plectin-null mice (lacking all plectin isoforms), which die shortly after birth because of severe skin blistering, plectin isoform 1-deficient mice were viable at birth, had a normal lifespan, and did not display the skin blistering phenotype. However, dermal fibroblasts isolated from plectin 1-deficient mice exhibited abnormalities in their actin cytoskeleton and impaired migration potential. Similarly, plectin 1-deficient T cells isolated from nymph nodes showed diminished chemotactic migration in vitro. Most strikingly, in vivo we found that leukocyte infiltration during wound healing was reduced in the mutant mice. These data show a specific role of a cytolinker protein in immune cell motility. Single isoform-deficient mice thus represent a powerful tool to unravel highly specific functions of plectin variants.
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Affiliation(s)
- Christina Abrahamsberg
- Department of Molecular Cell Biology, Max F. Perutz Laboratories, University of Vienna, Campus Vienna Biocenter 4, Dr. Bohrgasse 9, A-1030 Vienna, Austria
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