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Alieva IB, Shakhov AS, Dayal AA, Churkina AS, Parfenteva OI, Minin AA. Unique Role of Vimentin in the Intermediate Filament Proteins Family. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:726-736. [PMID: 38831508 DOI: 10.1134/s0006297924040114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 12/10/2023] [Accepted: 03/21/2024] [Indexed: 06/05/2024]
Abstract
Intermediate filaments (IFs), being traditionally the least studied component of the cytoskeleton, have begun to receive more attention in recent years. IFs are found in different cell types and are specific to them. Accumulated data have shifted the paradigm about the role of IFs as structures that merely provide mechanical strength to the cell. In addition to this role, IFs have been shown to participate in maintaining cell shape and strengthening cell adhesion. The data have also been obtained that point out to the role of IFs in a number of other biological processes, including organization of microtubules and microfilaments, regulation of nuclear structure and activity, cell cycle control, and regulation of signal transduction pathways. They are also actively involved in the regulation of several aspects of intracellular transport. Among the intermediate filament proteins, vimentin is of particular interest for researchers. Vimentin has been shown to be associated with a range of diseases, including cancer, cataracts, Crohn's disease, rheumatoid arthritis, and HIV. In this review, we focus almost exclusively on vimentin and the currently known functions of vimentin intermediate filaments (VIFs). This is due to the structural features of vimentin, biological functions of its domains, and its involvement in the regulation of a wide range of basic cellular functions, and its role in the development of human diseases. Particular attention in the review will be paid to comparing the role of VIFs with the role of intermediate filaments consisting of other proteins in cell physiology.
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Affiliation(s)
- Irina B Alieva
- Belozersky Institute of Physical and Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia
| | - Anton S Shakhov
- Belozersky Institute of Physical and Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia
| | - Alexander A Dayal
- Institute of Protein Research, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Aleksandra S Churkina
- Belozersky Institute of Physical and Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia
| | - Olga I Parfenteva
- Institute of Protein Research, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Alexander A Minin
- Institute of Protein Research, Russian Academy of Sciences, Moscow, 119334, Russia.
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2
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Müller WEG, Neufurth M, Wang S, Schröder HC, Wang X. Polyphosphate Nanoparticles: Balancing Energy Requirements in Tissue Regeneration Processes. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2309528. [PMID: 38470207 DOI: 10.1002/smll.202309528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 01/29/2024] [Indexed: 03/13/2024]
Abstract
Nanoparticles of a particular, evolutionarily old inorganic polymer found across the biological kingdoms have attracted increasing interest in recent years not only because of their crucial role in metabolism but also their potential medical applicability: it is inorganic polyphosphate (polyP). This ubiquitous linear polymer is composed of 10-1000 phosphate residues linked by high-energy anhydride bonds. PolyP causes induction of gene activity, provides phosphate for bone mineralization, and serves as an energy supplier through enzymatic cleavage of its acid anhydride bonds and subsequent ATP formation. The biomedical breakthrough of polyP came with the development of a successful fabrication process, in depot form, as Ca- or Mg-polyP nanoparticles, or as the directly effective polymer, as soluble Na-polyP, for regenerative repair and healing processes, especially in tissue areas with insufficient blood supply. Physiologically, the platelets are the main vehicles for polyP nanoparticles in the circulating blood. To be biomedically active, these particles undergo coacervation. This review provides an overview of the properties of polyP and polyP nanoparticles for applications in the regeneration and repair of bone, cartilage, and skin. In addition to studies on animal models, the first successful proof-of-concept studies on humans for the healing of chronic wounds are outlined.
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Affiliation(s)
- Werner E G Müller
- ERC Advanced Investigator Grant Research Group at the Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, D-55128, Mainz, Germany
| | - Meik Neufurth
- ERC Advanced Investigator Grant Research Group at the Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, D-55128, Mainz, Germany
| | - Shunfeng Wang
- ERC Advanced Investigator Grant Research Group at the Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, D-55128, Mainz, Germany
| | - Heinz C Schröder
- ERC Advanced Investigator Grant Research Group at the Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, D-55128, Mainz, Germany
| | - Xiaohong Wang
- ERC Advanced Investigator Grant Research Group at the Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University, Duesbergweg 6, D-55128, Mainz, Germany
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3
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Patteson AE, Carroll RJ, Iwamoto DV, Janmey PA. The vimentin cytoskeleton: when polymer physics meets cell biology. Phys Biol 2020; 18:011001. [PMID: 32992303 PMCID: PMC8240483 DOI: 10.1088/1478-3975/abbcc2] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The proper functions of tissues depend on the ability of cells to withstand stress and maintain shape. Central to this process is the cytoskeleton, comprised of three polymeric networks: F-actin, microtubules, and intermediate filaments (IFs). IF proteins are among the most abundant cytoskeletal proteins in cells; yet they remain some of the least understood. Their structure and function deviate from those of their cytoskeletal partners, F-actin and microtubules. IF networks show a unique combination of extensibility, flexibility and toughness that confers mechanical resilience to the cell. Vimentin is an IF protein expressed in mesenchymal cells. This review highlights exciting new results on the physical biology of vimentin intermediate filaments and their role in allowing whole cells and tissues to cope with stress.
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Affiliation(s)
- Alison E Patteson
- Physics Department, Syracuse University, Syracuse, NY 13244, USA
- BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
| | - Robert J Carroll
- Physics Department, Syracuse University, Syracuse, NY 13244, USA
- BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA
| | - Daniel V Iwamoto
- Institute for Medicine and Engineering, Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Paul A Janmey
- Institute for Medicine and Engineering, Department of Physiology, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
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4
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Danielsson F, Peterson MK, Caldeira Araújo H, Lautenschläger F, Gad AKB. Vimentin Diversity in Health and Disease. Cells 2018; 7:E147. [PMID: 30248895 PMCID: PMC6210396 DOI: 10.3390/cells7100147] [Citation(s) in RCA: 157] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 09/16/2018] [Accepted: 09/17/2018] [Indexed: 12/11/2022] Open
Abstract
Vimentin is a protein that has been linked to a large variety of pathophysiological conditions, including cataracts, Crohn's disease, rheumatoid arthritis, HIV and cancer. Vimentin has also been shown to regulate a wide spectrum of basic cellular functions. In cells, vimentin assembles into a network of filaments that spans the cytoplasm. It can also be found in smaller, non-filamentous forms that can localise both within cells and within the extracellular microenvironment. The vimentin structure can be altered by subunit exchange, cleavage into different sizes, re-annealing, post-translational modifications and interacting proteins. Together with the observation that different domains of vimentin might have evolved under different selection pressures that defined distinct biological functions for different parts of the protein, the many diverse variants of vimentin might be the cause of its functional diversity. A number of review articles have focussed on the biology and medical aspects of intermediate filament proteins without particular commitment to vimentin, and other reviews have focussed on intermediate filaments in an in vitro context. In contrast, the present review focusses almost exclusively on vimentin, and covers both ex vivo and in vivo data from tissue culture and from living organisms, including a summary of the many phenotypes of vimentin knockout animals. Our aim is to provide a comprehensive overview of the current understanding of the many diverse aspects of vimentin, from biochemical, mechanical, cellular, systems biology and medical perspectives.
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Affiliation(s)
- Frida Danielsson
- Science for Life Laboratory, Royal Institute of Technology, 17165 Stockholm, Sweden.
| | | | | | - Franziska Lautenschläger
- Campus D2 2, Leibniz-Institut für Neue Materialien gGmbH (INM) and Experimental Physics, NT Faculty, E 2 6, Saarland University, 66123 Saarbrücken, Germany.
| | - Annica Karin Britt Gad
- Centro de Química da Madeira, Universidade da Madeira, 9020105 Funchal, Portugal.
- Department of Medical Biochemistry and Microbiology, Uppsala University, 75237 Uppsala, Sweden.
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Robert A, Tian P, Adam SA, Kittisopikul M, Jaqaman K, Goldman RD, Gelfand VI. Kinesin-dependent transport of keratin filaments: a unified mechanism for intermediate filament transport. FASEB J 2018; 33:388-399. [PMID: 29944446 PMCID: PMC6355078 DOI: 10.1096/fj.201800604r] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Keratin intermediate filaments (IFs) are the major cytoskeletal component in epithelial cells. The dynamics of keratin IFs have been described to depend mostly on the actin cytoskeleton, but the rapid transport of fully polymerized keratin filaments has not been reported. In this work, we used a combination of photoconversion experiments and clustered regularly interspaced short palindromic repeats/clustered regularly interspaced short palindromic repeats-associated protein 9 genome editing to study the role of microtubules and microtubule motors in keratin filament transport. We found that long keratin filaments, like other types of IFs, are transported along microtubules by kinesin-1. Our data revealed that keratin and vimentin are nonconventional kinesin-1 cargoes because their transport did not require kinesin light chains, which are a typical adapter for kinesin-dependent cargo transport. Furthermore, we found that the same domain of the kinesin heavy chain tail is involved in keratin and vimentin IF transport, strongly suggesting that multiple types of IFs move along microtubules using an identical mechanism.-Robert, A., Tian, P., Adam, S. A., Kittisopikul, M., Jaqaman, K., Goldman, R. D., Gelfand, V. I. Kinesin-dependent transport of keratin filaments: a unified mechanism for intermediate filament transport.
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Affiliation(s)
- Amélie Robert
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Peirun Tian
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Stephen A Adam
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Mark Kittisopikul
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA.,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, USA; and
| | - Khuloud Jaqaman
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, USA; and.,Lyda Hill Department of Bioinformatics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Robert D Goldman
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Vladimir I Gelfand
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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6
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Leduc C, Etienne-Manneville S. Regulation of microtubule-associated motors drives intermediate filament network polarization. J Cell Biol 2017; 216:1689-1703. [PMID: 28432079 PMCID: PMC5461013 DOI: 10.1083/jcb.201607045] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 01/16/2017] [Accepted: 03/03/2017] [Indexed: 11/22/2022] Open
Abstract
Intermediate filaments (IFs) are key players in the control of cell morphology and structure as well as in active processes such as cell polarization, migration, and mechanoresponses. However, the regulatory mechanisms controlling IF dynamics and organization in motile cells are still poorly understood. In this study, we investigate the mechanisms leading to the polarized rearrangement of the IF network along the polarity axis. Using photobleaching and photoconversion experiments in glial cells expressing vimentin, glial fibrillary acidic protein, and nestin, we show that the distribution of cytoplasmic IFs results from a continuous turnover based on the cooperation of an actin-dependent retrograde flow and anterograde and retrograde microtubule-dependent transports. During wound-induced astrocyte polarization, IF transport becomes directionally biased from the cell center toward the cell front. Such asymmetry in the transport is mainly caused by a Cdc42- and atypical PKC-dependent inhibition of dynein-dependent retrograde transport. Our results show how polarity signaling can affect the dynamic turnover of the IF network to promote the polarization of the network itself.
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Affiliation(s)
- Cécile Leduc
- Institut Pasteur Paris, Cell Polarity, Migration and Cancer Unit, UMR 3691, Equipe Labellisée Ligue Contre le Cancer, Centre National de la Recherché Scientifique, 75724 Paris, France
| | - Sandrine Etienne-Manneville
- Institut Pasteur Paris, Cell Polarity, Migration and Cancer Unit, UMR 3691, Equipe Labellisée Ligue Contre le Cancer, Centre National de la Recherché Scientifique, 75724 Paris, France.
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Jiu Y, Peränen J, Schaible N, Cheng F, Eriksson JE, Krishnan R, Lappalainen P. Vimentin intermediate filaments control actin stress fiber assembly through GEF-H1 and RhoA. J Cell Sci 2017; 130:892-902. [PMID: 28096473 PMCID: PMC5358333 DOI: 10.1242/jcs.196881] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 01/04/2017] [Indexed: 12/17/2022] Open
Abstract
The actin and intermediate filament cytoskeletons contribute to numerous cellular processes, including morphogenesis, cytokinesis and migration. These two cytoskeletal systems associate with each other, but the underlying mechanisms of this interaction are incompletely understood. Here, we show that inactivation of vimentin leads to increased actin stress fiber assembly and contractility, and consequent elevation of myosin light chain phosphorylation and stabilization of tropomyosin-4.2 (see Geeves et al., 2015). The vimentin-knockout phenotypes can be rescued by re-expression of wild-type vimentin, but not by the non-filamentous ‘unit length form’ vimentin, demonstrating that intact vimentin intermediate filaments are required to facilitate the effects on the actin cytoskeleton. Finally, we provide evidence that the effects of vimentin on stress fibers are mediated by activation of RhoA through its guanine nucleotide exchange factor GEF-H1 (also known as ARHGEF2). Vimentin depletion induces phosphorylation of the microtubule-associated GEF-H1 on Ser886, and thereby promotes RhoA activity and actin stress fiber assembly. Taken together, these data reveal a new mechanism by which intermediate filaments regulate contractile actomyosin bundles, and may explain why elevated vimentin expression levels correlate with increased migration and invasion of cancer cells. Summary: Vimentin intermediate filaments control the activity of RhoA, and consequent stress fiber assembly and contractility by downregulating its guanine nucleotide exchange factor GEF-H1.
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Affiliation(s)
- Yaming Jiu
- Institute of Biotechnology, P.O. Box 56, University of Helsinki, Helsinki 00014, Finland
| | - Johan Peränen
- Faculty of Medicine, P.O. Box 63, University of Helsinki, Helsinki 00014, Finland
| | - Niccole Schaible
- Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Fang Cheng
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, FI-20520 Turku, Finland.,Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, POB 123, FI-20521 Turku, Finland
| | - John E Eriksson
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University, FI-20520 Turku, Finland.,Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, POB 123, FI-20521 Turku, Finland
| | - Ramaswamy Krishnan
- Department of Emergency Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Pekka Lappalainen
- Institute of Biotechnology, P.O. Box 56, University of Helsinki, Helsinki 00014, Finland
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8
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Boraas LC, Ahsan T. Lack of vimentin impairs endothelial differentiation of embryonic stem cells. Sci Rep 2016; 6:30814. [PMID: 27480130 PMCID: PMC4969593 DOI: 10.1038/srep30814] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 07/08/2016] [Indexed: 12/18/2022] Open
Abstract
The cytoskeletal filament vimentin is inherent to the endothelial phenotype and is critical for the proper function of endothelial cells in adult mice. It is unclear, however, if the presence of vimentin is necessary during differentiation to the endothelial phenotype. Here we evaluated gene and protein expression of differentiating wild type embryonic stem cells (WT ESCs) and vimentin knockout embryonic stem cells (VIM −/− ESCs) using embryoid bodies (EBs) formed from both cell types. Over seven days of differentiation VIM −/− EBs had altered morphology compared to WT EBs, with a rippled outer surface and a smaller size due to decreased proliferation. Gene expression of pluripotency markers decreased similarly for EBs of both cell types; however, VIM −/− EBs had impaired differentiation towards the endothelial phenotype. This was quantified with decreased expression of markers along the specification pathway, specifically the early mesodermal marker Brachy-T, the lateral plate mesodermal marker FLK1, and the endothelial-specific markers TIE2, PECAM, and VE-CADHERIN. Taken together, these results indicate that the absence of vimentin impairs spontaneous differentiation of ESCs to the endothelial phenotype in vitro.
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Affiliation(s)
- Liana C Boraas
- Department of Biomedical Engineering, Tulane University, New Orleans, LA, USA
| | - Tabassum Ahsan
- Department of Biomedical Engineering, Tulane University, New Orleans, LA, USA
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9
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Gefen A, Weihs D. Mechanical cytoprotection: A review of cytoskeleton-protection approaches for cells. J Biomech 2016; 49:1321-1329. [DOI: 10.1016/j.jbiomech.2015.10.030] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Revised: 10/20/2015] [Accepted: 10/21/2015] [Indexed: 12/28/2022]
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10
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Robert A, Rossow MJ, Hookway C, Adam SA, Gelfand VI. Vimentin filament precursors exchange subunits in an ATP-dependent manner. Proc Natl Acad Sci U S A 2015; 112:E3505-14. [PMID: 26109569 PMCID: PMC4500282 DOI: 10.1073/pnas.1505303112] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Intermediate filaments (IFs) are a component of the cytoskeleton capable of profound reorganization in response to specific physiological situations, such as differentiation, cell division, and motility. Various mechanisms were proposed to be responsible for this plasticity depending on the type of IF polymer and the biological context. For example, recent studies suggest that mature vimentin IFs (VIFs) undergo rearrangement by severing and reannealing, but direct subunit exchange within the filament plays little role in filament dynamics at steady state. Here, we studied the dynamics of subunit exchange in VIF precursors, called unit-length filaments (ULFs), formed by the lateral association of eight vimentin tetramers. To block vimentin assembly at the ULF stage, we used the Y117L vimentin mutant (vimentin(Y117L)). By tagging vimentin(Y117L) with a photoconvertible protein mEos3.2 and photoconverting ULFs in a limited area of the cytoplasm, we found that ULFs, unlike mature filaments, were highly dynamic. Subunit exchange among ULFs occurred within seconds and was limited by the diffusion of soluble subunits in the cytoplasm rather than by the association and dissociation of subunits from ULFs. Our data demonstrate that cells expressing vimentin(Y117L) contained a large pool of soluble vimentin tetramers that was in rapid equilibrium with ULFs. Furthermore, vimentin exchange in ULFs required ATP, and ATP depletion caused a dramatic reduction of the soluble tetramer pool. We believe that the dynamic exchange of subunits plays a role in the regulation of ULF assembly and the maintenance of a soluble vimentin pool during the reorganization of filament networks.
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Affiliation(s)
- Amélie Robert
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Molly J Rossow
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Caroline Hookway
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Stephen A Adam
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Vladimir I Gelfand
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
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11
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Bidirectional Interplay between Vimentin Intermediate Filaments and Contractile Actin Stress Fibers. Cell Rep 2015; 11:1511-8. [DOI: 10.1016/j.celrep.2015.05.008] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 04/21/2015] [Accepted: 05/04/2015] [Indexed: 01/06/2023] Open
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12
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Leduc C, Etienne-Manneville S. Intermediate filaments in cell migration and invasion: the unusual suspects. Curr Opin Cell Biol 2015; 32:102-12. [PMID: 25660489 DOI: 10.1016/j.ceb.2015.01.005] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Revised: 01/15/2015] [Accepted: 01/21/2015] [Indexed: 12/22/2022]
Abstract
Cell migration is a multistep process which relies on the coordination of cytoskeletal structures in space and time. While the roles of actin and microtubules have been investigated in great details, the lack of inhibitors and visualizing tools and the large number of proteins forming intermediate filaments (IFs) have delayed the characterization of IF functions during migration. However, a large body of evidence has progressively pointed to changes in IF composition as an important parameter in the regulation of cell migratory properties both during development and tumor invasion. More recent in-depth analyses show that IFs are dynamically reorganized to participate, together with microfilaments and microtubules, to the key steps leading to cell migration.
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Affiliation(s)
- Cécile Leduc
- Institut Pasteur - CNRS UMR 3691, Cell Polarity, Migration and Cancer Unit, 25 rue du Dr Roux, 75724 Paris Cedex 15, France
| | - Sandrine Etienne-Manneville
- Institut Pasteur - CNRS UMR 3691, Cell Polarity, Migration and Cancer Unit, 25 rue du Dr Roux, 75724 Paris Cedex 15, France.
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13
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Robert A, Herrmann H, Davidson MW, Gelfand VI. Microtubule-dependent transport of vimentin filament precursors is regulated by actin and by the concerted action of Rho- and p21-activated kinases. FASEB J 2014; 28:2879-90. [PMID: 24652946 DOI: 10.1096/fj.14-250019] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Intermediate filaments (IFs) form a dense and dynamic network that is functionally associated with microtubules and actin filaments. We used the GFP-tagged vimentin mutant Y117L to study vimentin-cytoskeletal interactions and transport of vimentin filament precursors. This mutant preserves vimentin interaction with other components of the cytoskeleton, but its assembly is blocked at the unit-length filament (ULF) stage. ULFs are easy to track, and they allow a reliable and quantifiable analysis of movement. Our results show that in cultured human vimentin-negative SW13 cells, 2% of vimentin-ULFs move along microtubules bidirectionally, while the majority are stationary and tightly associated with actin filaments. Rapid motor-dependent transport of ULFs along microtubules is enhanced ≥ 5-fold by depolymerization of actin cytoskeleton with latrunculin B. The microtubule-dependent transport of vimentin ULFs is further regulated by Rho-kinase (ROCK) and p21-activated kinase (PAK): ROCK inhibits ULF transport, while PAK stimulates it. Both kinases act on microtubule transport independently of their effects on actin cytoskeleton. Our study demonstrates the importance of the actin cytoskeleton to restrict IF transport and reveals a new role for PAK and ROCK in the regulation of IF precursor transport.-Robert, A., Herrmann, H., Davidson, M. W., and Gelfand, V. I. Microtubule-dependent transport of vimentin filament precursors is regulated by actin and by the concerted action of Rho- and p21-activated kinases.
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Affiliation(s)
- Amélie Robert
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Harald Herrmann
- Division of Molecular Genetics, German Cancer Research Center, Heidelberg, Germany; and
| | - Michael W Davidson
- National High Magnetic Field Laboratory and Department of Biological Science, Florida State University, Tallahassee, Florida, USA
| | - Vladimir I Gelfand
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA;
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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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Helfand BT, Mendez MG, Murthy SNP, Shumaker DK, Grin B, Mahammad S, Aebi U, Wedig T, Wu YI, Hahn KM, Inagaki M, Herrmann H, Goldman RD. Vimentin organization modulates the formation of lamellipodia. Mol Biol Cell 2011; 22:1274-89. [PMID: 21346197 PMCID: PMC3078081 DOI: 10.1091/mbc.e10-08-0699] [Citation(s) in RCA: 193] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The disassembly and withdrawal of vimentin intermediate filaments (VIF) from the plasma membrane induces membrane ruffling and the formation of a lamellipodium. Conversely, lamellipodium formation is inhibited when VIF are present. Vimentin intermediate filaments (VIF) extend throughout the rear and perinuclear regions of migrating fibroblasts, but only nonfilamentous vimentin particles are present in lamellipodial regions. In contrast, VIF networks extend to the entire cell periphery in serum-starved or nonmotile fibroblasts. Upon serum addition or activation of Rac1, VIF are rapidly phosphorylated at Ser-38, a p21-activated kinase phosphorylation site. This phosphorylation of vimentin is coincident with VIF disassembly at and retraction from the cell surface where lamellipodia form. Furthermore, local induction of photoactivatable Rac1 or the microinjection of a vimentin mimetic peptide (2B2) disassemble VIF at sites where lamellipodia subsequently form. When vimentin organization is disrupted by a dominant-negative mutant or by silencing, there is a loss of polarity, as evidenced by the formation of lamellipodia encircling the entire cell, as well as reduced cell motility. These findings demonstrate an antagonistic relationship between VIF and the formation of lamellipodia.
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Affiliation(s)
- Brian T Helfand
- Department of Urology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
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16
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Hubert T, Vandekerckhove J, Gettemans J. Unconventional actin conformations localize on intermediate filaments in mitosis. Biochem Biophys Res Commun 2011; 406:101-6. [PMID: 21295548 DOI: 10.1016/j.bbrc.2011.02.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 02/01/2011] [Indexed: 11/26/2022]
Abstract
Different structural conformations of actin have been identified in cells and shown to reside in distinct subcellular locations of cells. In this report, we describe the localization of actin on a cage-like structure in metaphase HEK 293T cells. Actin was detected with the anti-actin antibodies 1C7 and 2G2, but not with the anti-actin antibody C4. Actin contained in this structure is independent of microtubules and actin filaments, and colocalizes with vimentin. Taking advantage of intermediate filament collapse into a perinuclear dense mass of cables when microtubules are depolymerized, we were able to relocalize actin to such structures. We hypothesize that phosphorylation of intermediate filaments at mitosis entry triggers the recruitment of different actin conformations to mitotic intermediate filaments. Storage and partition of the nuclear actin and antiparallel "lower dimer" actin conformations between daughter cells possibly contribute to gene transcription and transient actin filament dynamics at G1 entry.
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Affiliation(s)
- Thomas Hubert
- Department of Medical Protein Research, VIB, Ghent University, Faculty of Medicine and Health Sciences, Albert Baertsoenkaai 3, B-9000 Ghent, Belgium
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17
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Hall PF. Actions of Corticotropin on the Adrenal Cortex: Biochemistry and Cell Biology. Compr Physiol 2011. [DOI: 10.1002/cphy.cp070404] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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18
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Mazumder A, Roopa T, Kumar A, Iyer KV, Ramdas NM, Shivashankar GV. Prestressed nuclear organization in living cells. Methods Cell Biol 2010; 98:221-39. [PMID: 20816237 DOI: 10.1016/s0091-679x(10)98010-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The nucleus is maintained in a prestressed state within eukaryotic cells, stabilized mechanically by chromatin structure and other nuclear components on its inside, and cytoskeletal components on its outside. Nuclear architecture is emerging to be critical to the governance of chromatin assembly, regulation of genome function and cellular homeostasis. Elucidating the prestressed organization of the nucleus is thus important to understand how the nuclear architecture impinges on its function. In this chapter, various chemical and mechanical methods have been described to probe the prestressed organization of the nucleus.
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Affiliation(s)
- Aprotim Mazumder
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bellary Road, Bangalore 560065, India
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19
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Chang L, Barlan K, Chou YH, Grin B, Lakonishok M, Serpinskaya AS, Shumaker DK, Herrmann H, Gelfand VI, Goldman RD. The dynamic properties of intermediate filaments during organelle transport. J Cell Sci 2009; 122:2914-23. [PMID: 19638410 DOI: 10.1242/jcs.046789] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Intermediate filament (IF) dynamics during organelle transport and their role in organelle movement were studied using Xenopus laevis melanophores. In these cells, pigment granules (melanosomes) move along microtubules and microfilaments, toward and away from the cell periphery in response to alpha-melanocyte stimulating hormone (alpha-MSH) and melatonin, respectively. In this study we show that melanophores possess a complex network of vimentin IFs which interact with melanosomes. IFs form an intricate, honeycomb-like network that form cages surrounding individual and small clusters of melanosomes, both when they are aggregated and dispersed. Purified melanosome preparations contain a substantial amount of vimentin, suggesting that melanosomes bind to IFs. Analyses of individual melanosome movements in cells with disrupted IF networks show increased movement of granules in both anterograde and retrograde directions, further supporting the notion of a melanosome-IF interaction. Live imaging reveals that IFs, in turn, become highly flexible as melanosomes disperse in response to alpha-MSH. During the height of dispersion there is a marked increase in the rate of fluorescence recovery after photobleaching of GFP-vimentin IFs and an increase in vimentin solubility. These results reveal a dynamic interaction between membrane bound pigment granules and IFs and suggest a role for IFs as modulators of granule movement.
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Affiliation(s)
- Lynne Chang
- Department of Microbiology and Molecular Genetics, Harvard Medical School, Harvard University, Boston, MA, USA
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20
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Eriksson JE, Dechat T, Grin B, Helfand B, Mendez M, Pallari HM, Goldman RD. Introducing intermediate filaments: from discovery to disease. J Clin Invest 2009; 119:1763-71. [PMID: 19587451 DOI: 10.1172/jci38339] [Citation(s) in RCA: 301] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
It took more than 100 years before it was established that the proteins that form intermediate filaments (IFs) comprise a unified protein family, the members of which are ubiquitous in virtually all differentiated cells and present both in the cytoplasm and in the nucleus. However, during the past 2 decades, knowledge regarding the functions of these structures has been expanding rapidly. Many disease-related roles of IFs have been revealed. In some cases, the molecular mechanisms underlying these diseases reflect disturbances in the functions traditionally assigned to IFs, i.e., maintenance of structural and mechanical integrity of cells and tissues. However, many disease conditions seem to link to the nonmechanical functions of IFs, many of which have been defined only in the past few years.
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Affiliation(s)
- John E Eriksson
- Department of Biology, Abo Akademi University, Turku, Finland.
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21
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Li YC, Bai WZ, Sakai K, Hashikawa T. Fluorescence and electron microscopic localization of F-actin in the ependymocytes. J Histochem Cytochem 2009; 57:741-51. [PMID: 19365089 DOI: 10.1369/jhc.2009.953646] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The organization of F-actin in the ventricular system has been reported to display pronounced regional differences with respect to shape, size, and development. However, the real roles played by F-actin in these cells cannot be understood unless the precise localization of F-actin is defined. In the present study, we used double-fluorescence labeling to further examine the localization of F-actin in the ependymocytes and its spatial relation to the other two cytoskeletal components, microtubules and intermediate filaments. Then we converted fluorescence signals for F-actin to peroxidase/DAB reaction products by use of a phalloidin-based FITC-anti-FITC system. This detection technique provided an overview of the distribution of F-actin in the ependymocytes at the ultrastructural level, and has been proven to be helpful in correlating light and electron microscopic investigations.
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Affiliation(s)
- Yan-Chao Li
- Neural Architecture, Advanced Technology Development Group, RIKEN Brain Science Institute, Hirosawa 2-1, Wako, Saitama 351-0198, Japan.
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22
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Li YC, Bai WZ, Hashikawa T. Postnatal reorganization of F-actin in the central canal of the spinal cord in the rat. Brain Res 2008; 1239:100-6. [DOI: 10.1016/j.brainres.2008.08.045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Revised: 08/14/2008] [Accepted: 08/15/2008] [Indexed: 11/26/2022]
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23
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The contractile segment of the abneural limbus in the gecko cochlea is enriched in vimentin. Cell Tissue Res 2007; 330:405-12. [DOI: 10.1007/s00441-007-0475-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Accepted: 07/13/2007] [Indexed: 11/25/2022]
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24
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Li YC, Bai WZ, Hashikawa T. Regionally varying F-actin network in the apical cytoplasm of ependymocytes. Neurosci Res 2006; 57:522-30. [PMID: 17239462 DOI: 10.1016/j.neures.2006.12.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2006] [Revised: 12/13/2006] [Accepted: 12/14/2006] [Indexed: 10/23/2022]
Abstract
F-actin participates in morphogenetic cell-shape changes and helps maintain cellular integrity. Actin-like proteins have been detected in the ependymocytes of the cerebral ventricles, but the distribution of F-actin along the ventricular system has not been studied. We observed a highly ordered and regionally varying F-actin network in the apical cytoplasm of the ependyma in the ventricular system of rats using fluorescein isothiocyanate-conjugated phalloidin. Dense F-actin bundles spanned the entire circumference of the central canal of the spinal cord and formed a characteristic ring-like network in the apical region. The apical F-actin layer was widest in the lower cervical canal, and narrower in the upper thoracic canal. However, in the lower part of the filum terminale, the apical F-actin bundles became sparser and even disappeared. The apical F-actin layer differs significantly between the ventral and dorsal aspects above the medulla oblongata. This suggests that the regionally varying distribution of F-actin reflects the diverse local demands of the ependymocytes for cellular integrity and adhesive activity against external forces.
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Affiliation(s)
- Yan-Chao Li
- Laboratory for Neural Architecture, RIKEN Brain Science Institute, Hirosawa 2-1, Wako-Shi, Saitama 351-0198, Japan.
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25
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Launay N, Goudeau B, Kato K, Vicart P, Lilienbaum A. Cell signaling pathways to αB-crystallin following stresses of the cytoskeleton. Exp Cell Res 2006; 312:3570-84. [PMID: 16979163 DOI: 10.1016/j.yexcr.2006.07.025] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2006] [Revised: 07/28/2006] [Accepted: 07/30/2006] [Indexed: 12/26/2022]
Abstract
Small heat shock proteins (sHSPs) act as chaperone, but also in protecting the different cytoskeletal components. Recent results suggest that alphaB-crystallin, a member of sHSPs family, might regulate actin filament dynamics, stabilize them in a phosphorylation dependent manner, and protect the integrity of intermediate filaments (IF) against extracellular stress. We demonstrate that vinblastin and cytochalasin D, which respectively disorganize microtubules and actin microfilaments, trigger the activation of the p38/MAPKAP2 kinase pathway and lead to the specific alphaB-crystallin phosphorylation at serine 59. Upstream of p38, we found that RhoK, PKC and PKA are selectively involved in the activation of p38 and phosphorylation of alphaB-crystallin, depending on the cytoskeletal network disorganized. Moreover, we demonstrate that chronic perturbations of IF network result in the same activation of p38 MAPK and alphaB-crystallin phosphorylation, as with severe disorganization of other cytoskeletal networks. Finally, we also show that Ser 59 phosphorylated alphaB-crystallin colocalizes with cytoskeletal components. Thus, disturbance of cytoskeleton leads by converging signaling pathways to the phosphorylation of alphaB-crystallin, which probably acts as a protective effector of the cytoskeleton.
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Affiliation(s)
- Nathalie Launay
- EA 300 Stress et Pathologies du Cytosquelette, UFR de Biochimie, Université Paris 7, 2 place Jussieu, 75005 Paris, France
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26
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Esue O, Carson AA, Tseng Y, Wirtz D. A direct interaction between actin and vimentin filaments mediated by the tail domain of vimentin. J Biol Chem 2006; 281:30393-9. [PMID: 16901892 DOI: 10.1074/jbc.m605452200] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The assembly and organization of the three major eukaryotic cytoskeleton proteins, actin, microtubules, and intermediate filaments, are highly interdependent. Through evolution, cells have developed specialized multifunctional proteins that mediate the cross-linking of these cytoskeleton filament networks. Here we test the hypothesis that two of these filamentous proteins, F-actin and vimentin filament, can interact directly, i.e. in the absence of auxiliary proteins. Through quantitative rheological studies, we find that a mixture of vimentin/actin filament network features a significantly higher stiffness than that of networks containing only actin filaments or only vimentin filaments. Maximum inter-filament interaction occurs at a vimentin/actin molar ratio of 3 to 1. Mixed networks of actin and tailless vimentin filaments show low mechanical stiffness and much weaker inter-filament interactions. Together with the fact that cells featuring prominent vimentin and actin networks are much stiffer than their counterparts lacking an organized actin or vimentin network, these results suggest that actin and vimentin filaments can interact directly through the tail domain of vimentin and that these inter-filament interactions may contribute to the overall mechanical integrity of cells and mediate cytoskeletal cross-talk.
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Affiliation(s)
- Osigwe Esue
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
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27
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Abstract
Intermediate filaments, actin-containing microfilaments and microtubules are the three main cytoskeletal systems of vertebrate and many invertebrate cells. Although these systems are composed of distinctly different proteins, they are in constant and intimate communication with one another. Understanding the molecular basis of this cytoskeletal crosstalk is essential for determining the mechanisms that underlie many cell-biological phenomena. Recent studies have revealed that intermediate filaments and their associated proteins are important components in mediating this crosstalk.
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Affiliation(s)
- Lynne Chang
- Feinberg School of Medicine, Northwestern University, Department of Cell and Molecular Biology, 303 East Chicago Avenue, Chicago, Illinois 60611, USA.
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28
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Ito JI, Yokoyama S. Sialosylcholesterol induces reorganization of astrocyte filament network. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1495:195-202. [PMID: 10699458 DOI: 10.1016/s0167-4889(00)00002-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Sialosylcholesterol induces the differentiation of astrocytes with respect to their morphological appearance (Kato et al., Brain Res. 438 (1988) 277-285; Ito et al., 481 (1989) 335-343), while in a cell-free condition it depolymerizes the astrocyte cellular filaments, the glia filaments and microfilaments (Ito et al., J. Neurochem. 61 (1993) 80-84). To solve this paradox, we examined hetero-interaction between the glia filaments and microfilaments in the presence of sialosylcholesterol. Each filament was prepared in a depolymerized form in low ionic strength, and was adjusted to physiological ionic strength to prevent from repolymerization by sialosylcholesterol. When the two filament preparations in this form were mixed, repolymerization took place in spite of the presence of sialosylcholesterol. The filament formed in the mixture was found almost exclusively composed of vimentin and actin, the major component of the glia filaments and microfilaments preparation, respectively. An excess amount of vimentin over actin in the precipitate implicated that the main mechanism for the hetero-polymerization was the enhancement of vimentin polymerization by actin. To support this view, pre-polymerization of the microfilaments before mixing with the depolymerized glia filaments resulted in a marked decrease in polymerization of the glia filaments. A similar hetero-interaction was found between the purified vimentin and actin. When polymerized vimentin and actin were directly depolymerized by sialosylcholesterol and mixed, polymer formation was demonstrated between these two proteins. Electronmicroscopy indicated direct interaction of the actin filament with the vimentin filament. The results indicate that sialosylcholesterol induces reorganization of the cellular filament network, such as disorganization of vimentin and actin filaments, and provokes their hetero-interaction to form the hetero-filament. Hence, this may be one of the key mechanisms for the induction of cellular differentiation by sialocylcholesterol.
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Affiliation(s)
- J I Ito
- Biochemistry 1, Nagoya City University Medical School, Kawasumi 1, Mizuho-cho, Mizuho-ku, Nagoya, Japan.
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29
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Trinczek B, Ebneth A, Mandelkow EM, Mandelkow E. Tau regulates the attachment/detachment but not the speed of motors in microtubule-dependent transport of single vesicles and organelles. J Cell Sci 1999; 112 ( Pt 14):2355-67. [PMID: 10381391 DOI: 10.1242/jcs.112.14.2355] [Citation(s) in RCA: 221] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
We have performed a real time analysis of fluorescence-tagged vesicle and mitochondria movement in living CHO cells transfected with microtubule-associated protein tau or its microtubule-binding domain. tau does not alter the speed of moving vesicles, but it affects the frequencies of attachment and detachment to the microtubule tracks. Thus, tau decreases the run lengths both for plus-end and minus-end directed motion to an equal extent. Reversals from minus-end to plus-end directed movement of single vesicles are strongly reduced by tau, but reversals in the opposite direction (plus to minus) are not. Analogous effects are observed with the transport of mitochondria and even with that of vimentin intermediate filaments. The net effect is a directional bias in the minus-end direction of microtubules which leads to the retraction of mitochondria or vimentin IFs towards the cell center. The data suggest that tau can control intracellular trafficking by affecting the attachment and detachment cycle of the motors, in particular by reducing the attachment of kinesin to microtubules, whereas the movement itself is unaffected.
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Affiliation(s)
- B Trinczek
- Max-Planck Unit for Structural Molecular Biology, Notkestrasse 85, D-22607 Hamburg, Germany.
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30
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Kreitzer G, Liao G, Gundersen GG. Detyrosination of tubulin regulates the interaction of intermediate filaments with microtubules in vivo via a kinesin-dependent mechanism. Mol Biol Cell 1999; 10:1105-18. [PMID: 10198060 PMCID: PMC25238 DOI: 10.1091/mbc.10.4.1105] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Posttranslationally modified forms of tubulin accumulate in the subset of stabilized microtubules (MTs) in cells but are not themselves involved in generating MT stability. We showed previously that stabilized, detyrosinated (Glu) MTs function to localize vimentin intermediate filaments (IFs) in fibroblasts. To determine whether tubulin detyrosination or MT stability is the critical element in the preferential association of IFs with Glu MTs, we microinjected nonpolymerizable Glu tubulin into cells. If detyrosination is critical, then soluble Glu tubulin should be a competitive inhibitor of the IF-MT interaction. Before microinjection, Glu tubulin was rendered nonpolymerizable and nontyrosinatable by treatment with iodoacetamide (IAA). Microinjected IAA-Glu tubulin disrupted the interaction of IFs with MTs, as assayed by the collapse of IFs to a perinuclear location, and had no detectable effect on the array of Glu or tyrosinated MTs in cells. Conversely, neither IAA-tyrosinated tubulin nor untreated Glu tubulin, which assembled into MTs, caused collapse of IFs when microinjected. The epitope on Glu tubulin responsible for interfering with the Glu MT-IF interaction was mapped by microinjecting tubulin fragments of alpha-tubulin. The 14-kDa C-terminal fragment of Glu tubulin (alpha-C Glu) induced IF collapse, whereas the 36-kDa N-terminal fragment of alpha-tubulin did not alter the IF array. The epitope required more than the detyrosination site at the C terminus, because a short peptide (a 7-mer) mimicking the C terminus of Glu tubulin did not disrupt the IF distribution. We previously showed that kinesin may mediate the interaction of Glu MTs and IFs. In this study we found that kinesin binding to MTs in vitro was inhibited by the same reagents (i.e., IAA-Glu tubulin and alpha-C Glu) that disrupted the IF-Glu MT interaction in vivo. These results demonstrate for the first time that tubulin detyrosination functions as a signal for the recruitment of IFs to MTs via a mechanism that is likely to involve kinesin.
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Affiliation(s)
- G Kreitzer
- Department of Pathology, Columbia University, College of Physicians and Surgeons, New York, New York 10032, USA
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31
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Sin WC, Chen XQ, Leung T, Lim L. RhoA-binding kinase alpha translocation is facilitated by the collapse of the vimentin intermediate filament network. Mol Cell Biol 1998; 18:6325-39. [PMID: 9774649 PMCID: PMC109219 DOI: 10.1128/mcb.18.11.6325] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The regulation of morphological changes in eukaryotic cells is a complex process involving major components of the cytoskeleton including actin microfilaments, microtubules, and intermediate filaments (IFs). The putative effector of RhoA, RhoA-binding kinase alpha (ROKalpha), is a serine/threonine kinase that has been implicated in the reorganization of actin filaments and in myosin contractility. Here, we show that ROKalpha also directly affects the structural integrity of IFs. Overexpression of active ROKalpha, like that of RhoA, caused the collapse of filamentous vimentin, a type III IF. A RhoA-binding-deficient, kinase-inactive ROKalpha inhibited the collapse of vimentin IFs induced by RhoA in HeLa cells. In vitro, ROKalpha bound and phosphorylated vimentin at its head-rod domain, thereby inhibiting the assembly of vimentin. ROKalpha colocalized predominantly with the filamentous vimentin network, which remained intact in serum-starved cells. Treatment of cells with vinblastine, a microtubule-disrupting agent, also resulted in filamentous vimentin collapse and concomitant ROKalpha translocation to the cell periphery. ROKalpha translocation did not occur when the vimentin network remained intact in vinblastine-treated cells at 4 degreesC or in the presence of the dominant-negative RhoAN19 mutant. Transient translocation of ROKalpha was also observed in cells subjected to heat shock, which caused the disassembly of the vimentin network. Thus, the translocation of ROKalpha to the cell periphery upon overexpression of RhoAV14 or growth factor treatment is associated with disassembly of vimentin IFs. These results indicate that Rho effectors known to act on microfilaments may be involved in regulating the assembly of IFs. Vimentin when phosphorylated also exhibits reduced affinity for the inactive ROKalpha. The translocation of ROKalpha from IFs to the cell periphery upon action by activated RhoA and ROKalpha suggests that ROKalpha may initiate its own cascade of activation.
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Affiliation(s)
- W C Sin
- Glaxo-IMCB Group, Institute of Molecular and Cell Biology, Singapore 117609, Singapore
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32
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Yoon M, Moir RD, Prahlad V, Goldman RD. Motile properties of vimentin intermediate filament networks in living cells. J Cell Biol 1998; 143:147-57. [PMID: 9763427 PMCID: PMC2132819 DOI: 10.1083/jcb.143.1.147] [Citation(s) in RCA: 197] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The motile properties of intermediate filament (IF) networks have been studied in living cells expressing vimentin tagged with green fluorescent protein (GFP-vimentin). In interphase and mitotic cells, GFP-vimentin is incorporated into the endogenous IF network, and accurately reports the behavior of IF. Time-lapse observations of interphase arrays of vimentin fibrils demonstrate that they are constantly changing their configurations in the absence of alterations in cell shape. Intersecting points of vimentin fibrils, or foci, frequently move towards or away from each other, indicating that the fibrils can lengthen or shorten. Fluorescence recovery after photobleaching shows that bleach zones across fibrils rapidly recover their fluorescence. During this recovery, bleached zones frequently move, indicating translocation of fibrils. Intriguingly, neighboring fibrils within a cell can exhibit different rates and directions of movement, and they often appear to extend or elongate into the peripheral regions of the cytoplasm. In these same regions, short filamentous structures are also seen actively translocating. All of these motile properties require energy, and the majority appear to be mediated by interactions of IF with microtubules and microfilaments.
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Affiliation(s)
- M Yoon
- Northwestern University Medical School, Department of Cell and Molecular Biology, Chicago, Illinois 60611, USA
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33
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Prahlad V, Yoon M, Moir RD, Vale RD, Goldman RD. Rapid movements of vimentin on microtubule tracks: kinesin-dependent assembly of intermediate filament networks. J Biophys Biochem Cytol 1998; 143:159-70. [PMID: 9763428 PMCID: PMC2132817 DOI: 10.1083/jcb.143.1.159] [Citation(s) in RCA: 273] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The assembly and maintenance of an extended intermediate filament (IF) network in fibroblasts requires microtubule (MT) integrity. Using a green fluorescent protein-vimentin construct, and spreading BHK-21 cells as a model system to study IF-MT interactions, we have discovered a novel mechanism involved in the assembly of the vimentin IF cytoskeleton. This entails the rapid, discontinuous, and MT-dependent movement of IF precursors towards the peripheral regions of the cytoplasm where they appear to assemble into short fibrils. These precursors, or vimentin dots, move at speeds averaging 0.55 +/- 0.24 micrometer/s. The vimentin dots colocalize with MT and their motility is inhibited after treatment with nocodazole. Our studies further implicate a conventional kinesin in the movement of the vimentin dots. The dots colocalize with conventional kinesin as shown by indirect immunofluorescence, and IF preparations from spreading cells are enriched in kinesin. Furthermore, microinjection of kinesin antibodies into spreading cells prevents the assembly of an extended IF network. These studies provide insights into the interactions between the IF and MT systems. They also suggest a role for conventional kinesin in the distribution of non-membranous protein cargo, and the local regulation of IF assembly.
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Affiliation(s)
- V Prahlad
- Department of Cell and Molecular Biology, Northwestern University Medical School, Chicago, Illinois 60611, USA
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34
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Safiejko-Mroczka B, Bell PB. Distribution of cytoskeletal proteins in neomycin-induced protrusions of human fibroblasts. Exp Cell Res 1998; 242:495-514. [PMID: 9683537 DOI: 10.1006/excr.1997.3871] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The organization of actin, tubulin, and vimentin was studied in protruding lamellae of human fibroblasts induced by the aminoglycoside antibiotic neomycin, an inhibitor of the phosphatidylinositol cycle. Neomycin stimulates the simultaneous protrusion of lamellae in all treated cells, and the lamellae remain extended for about 15-20 min, before gradually withdrawing. The pattern and distribution of actin, tubulin, and vimentin during neomycin stimulation were analyzed by fluorescence and electron microscopy. F-actin in the newly formed lamellae is localized in a marginal band at the leading edge. Tubulin is colocalized with F-actin in the marginal band, but the newly formed lamellae are initially devoid of microtubules. Over a period of 10 to 20 min after the addition of neomycin, microtubules grow into the lamellae from the adjacent cytoplasm, while the intensity of tubulin staining of the marginal band decreases. Distribution of vimentin remains unchanged in neomycin-treated cells and vimentin filaments do not enter the new protrusions. Treatment of cells with colchicine and Taxol do not inhibit neomycin-induced protrusion but protrusions are no longer localized at the ends of cell processes and occur all around the cell periphery. We conclude that actin filaments are the major component of the cytoskeleton involved in generating protrusions. Microtubules and, possibly, intermediate filaments control the pattern of protrusions by their interaction with actin filaments.
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Affiliation(s)
- B Safiejko-Mroczka
- Department of Zoology, The University of Oklahoma, Norman, Oklahoma, 73019, USA.
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35
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Valgeirsdóttir S, Claesson-Welsh L, Bongcam-Rudloff E, Hellman U, Westermark B, Heldin CH. PDGF induces reorganization of vimentin filaments. J Cell Sci 1998; 111 ( Pt 14):1973-80. [PMID: 9645945 DOI: 10.1242/jcs.111.14.1973] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this study we demonstrate that stimulation with platelet-derived growth factor (PDGF) leads to a marked reorganization of the vimentin filaments in porcine aortic endothelial (PAE) cells ectopically expressing the PDGF beta-receptor. Within 20 minutes after stimulation, the well-spread fine fibrillar vimentin was reorganized as the filaments aggregated into a dense coil around the nucleus. The solubility of vimentin upon Nonidet-P40-extraction of cells decreased considerably after PDGF stimulation, indicating that PDGF caused a redistribution of vimentin to a less soluble compartment. In addition, an increased tyrosine phosphorylation of vimentin was observed. The redistribution of vimentin was not a direct consequence of its tyrosine phosphorylation, since treatment of cells with an inhibitor for the cytoplasmic tyrosine kinase Src, attenuated phosphorylation but not redistribution of vimentin. These changes in the distribution of vimentin occurred in conjunction with reorganization of actin filaments. In PAE cells expressing a Y740/751F mutant receptor that is unable to bind and activate phosphatidylinositol 3′-kinase (PI3-kinase), the distribution of vimentin was virtually unaffected by PDGF stimulation. Thus, PI3-kinase is important for vimentin reorganization, in addition to its previously demonstrated role in actin reorganization. The small GTPase Rac has previously been shown to be involved downstream of PI3-kinase in the reorganization of actin filaments. In PAE cells overexpressing dominant negative Rac1 (N17Rac1), no change in the fine fibrillar vimentin network was seen after PDGF-BB stimulation, whereas in PAE cells overexpressing constitutively active Rac1 (V12Rac1), there was a dramatic change in vimentin filament organization independent of PDGF stimulation. These data indicate that PDGF causes a reorganization of microfilaments as well as intermediate filaments in its target cells and suggest an important role for Rac downstream of PI3-kinase in the PDGF stimulated reorganization of both actin and vimentin filaments.
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Affiliation(s)
- S Valgeirsdóttir
- Ludwig Institute for Cancer Research, Biomedical Center, Uppsala, Sweden
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Chu JJ, Chen KD, Lin YL, Fei CY, Chiang AS, Chiang CD, Lai YK. Taxol induces concomitant hyperphosphorylation and reorganization of vimentin intermediate filaments in 9l rat brain tumor cells. J Cell Biochem 1998. [DOI: 10.1002/(sici)1097-4644(19980315)68:4<472::aid-jcb7>3.0.co;2-n] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Oakley C, Jaeger NA, Brunette DM. Sensitivity of fibroblasts and their cytoskeletons to substratum topographies: topographic guidance and topographic compensation by micromachined grooves of different dimensions. Exp Cell Res 1997; 234:413-24. [PMID: 9260912 DOI: 10.1006/excr.1997.3625] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Fibroblasts alter their shape, orientation, and direction of movement to align with the direction of micromachined grooves, exhibiting a phenomenon termed topographic guidance. In this study we examined the ability of the microtubule and actin microfilament bundle systems, either in combination with or independently from each other, to affect alignment of human gingival fibroblasts on sets of micromachined grooves of different dimensions. To assess specifically the role of microtubules and actin microfilament bundles, we examined cell alignment, over time, in the presence or absence of specific inhibitors of microtubules (colcemid) and actin microfilament bundles (cytochalasin B). Using time-lapse videomicroscopy, computer-assisted morphometry and confocal microscopy of the cytoskeleton we found that the dimensions of the grooves influenced the kinetics of cell alignment irrespective of whether cytoskeletons were intact or disturbed. Either an intact microtubule or an intact actin microfilament-bundle system could produce cell alignment with an appropriate substratum. Cells with intact microtubules aligned to smaller topographic features than cells deficient in microtubules. Moreover, cells deficient in microtubules required significantly more time to become aligned. An unexpected finding was that very narrow 0.5-microm-wide and 0.5-microm-deep grooves aligned cells deficient in actin microfilament bundles (cytochalasin B-treated) better than untreated control cells but failed to align cells deficient in microtubules yet containing microfilament bundles (colcemid treated). Thus, the microtubule system appeared to be the principal but not sole cytoskeletal substratum-response mechanism affecting topographic guidance of human gingival fibroblasts. This study also demonstrated that micromachined substrata can be useful in dissecting the role of microtubules and actin microfilament bundles in cell behaviors such as contact guidance and cell migration without the use of drugs such as cytochalasin and colcemid.
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Affiliation(s)
- C Oakley
- Department of Oral Biology, University of British Columbia, Vancouver, Canada
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Hartig R, Huang Y, Janetzko A, Shoeman R, Grüb S, Traub P. Binding of fluorescence- and gold-labeled oligodeoxyribonucleotides to cytoplasmic intermediate filaments in epithelial and fibroblast cells. Exp Cell Res 1997; 233:169-86. [PMID: 9184086 DOI: 10.1006/excr.1997.3543] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Previously, in vitro experiments have demonstrated the capacity of intermediate filaments (IFs) to associate with polyanionic compounds, including nucleic acids. To prove that this activity is also shown by IFs in quasi-intact cells, digitonin-permeabilized epithelial PtK2 and mouse fibroblast cells were treated with FITC-labeled, single-stranded oligodeoxyribonucleotides and analyzed, after indirect decoration of their IF systems with TRITC-conjugated antibodies, by fluorescence microscopy. While cytokeratin IFs exhibited a strong affinity for and exact codistribution with oligo(dG)25, vimentin IFs were less active in binding this oligonucleotide. Other oligonucleotides, like oligo(dT)25, oligo[d(GT)12G] and oligo[d(G3T2A)4G], were bound to IFs with lower efficiency. In general, the introduction of dA residues into oligo(dG)n or oligo(dGT)n tracts reduced the IF-binding potential of the nucleic acids. This, however, increased significantly upon reduction of the ionic strength to half physiological, indicating a strong electrostatic binding component. The binding reaction was often obscured by simultaneous association of the oligonucleotides with cellular membranes mostly in the perinuclear region, an activity that was largely abolished by prior cell extraction with nonionic detergent. Strongly IF-binding oligonucleotides also disassembled microtubules, presumably via their interaction with microtubule-associated proteins, but left microfilaments intact. In PtK2 cells, oligo(dG)25-loaded IFs were frequently seen coaligned with microfilaments and to cross-bridge stress fibers with the formation of rope ladder-like configurations. Employing microinjection and confocal laser scanning microscopy, association of IFs with oligonucleotides could also be visualized in intact cells. In accord with these fluorescence microscopic data, transmission electron microscopy of permeabilized cells treated with gold-conjugated oligonucleotides revealed decoration of IFs and membrane systems with gold particles, whereby in PtK2 cells these structures showed a distinctly heavier labeling than in fibroblasts. These results demonstrate that in animal cells IFs are able to bind nucleic acids and, very likely, also nucleoprotein particles and suggest that this capacity is exploited by the cells for transient storage and, in cooperation with microtubules and microfilaments, controlled transport of such material in the cytoplasm.
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Affiliation(s)
- R Hartig
- Max-Planck-Institut für Zellbiologie, Rosenhof, Ladenburg/Heidelberg, Germany
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39
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Abstract
The problem for the steroidogenic cell if it is to accelerate steroid synthesis in response to trophic stimulation, consists in moving cholesterol from the sites of synthesis and storage to mitochondria at an accelerated rate. The most intensely studied situation is that in which the sterol is stored as ester in lipid droplets. Cholesterol ester must be de-esterified and transported to mitochondria where steroid synthesis begins. Since droplets and mitochondria are now known to be attached to intermediate filaments and since these structures are not contractile, it appears to be necessary to invoke the actions of other cytoskeletal elements. Actin microfilaments are involved in cholesterol transport so that it is tempting to propose that the contractile properties of actomyosin are used in this process. It is known that an energy-dependent contractile process involving actin is capable of disrupting intermediate filaments. Since the intermediate filaments appear to act by keeping lipid droplets and mitochondria apart, disruption of the filaments accompanied by a contractile process would be expected to allow these two structures to come together. This would open the way for the transfer of cholesterol to the steroidogenic pathway. This should be regarded as a first step. The events necessary for entry of cholesterol from droplets into the mitochondria remain to be clarified. In addition, the transport process for newly synthesized cholesterol that is not stored in droplets, is still not understood. At least four protein kinase enzymes have been identified in the cytoskeletons of adrenal cells, namely, Ca2+/calmodulin-dependent kinase, protein kinase (Ca2+ and phospholipid-dependent), myosin light chain kinase, and protein kinase A (cyclic AMP-dependent). The Ca2+/calmodulin kinase promotes transport of cholesterol to mitochondria and does so under conditions in which phosphorylation of vimentin and myosin light chain occurs. Phosphorylation of vimentin results in disruption of intermediate filaments while phosphorylation of light chain promotes contraction of the actomyosin ring. It now appears that intermediate filaments are cross-linked by actin filaments so that such contraction would be expected to produce significant structural changes in the cytoskeleton and the attached organelles. Although the details of the changes taking place in the organ in vivo are not known, the potential for interaction between droplets and mitochondria as the result of these changes in intermediate filaments and actomyosin, is clear. Protein kinase C is activated by ACTH and cyclic AMP, although this activation does not appear to be directly involved in the regulation of steroid synthesis. Nevertheless, vimentin is a substrate for this enzyme, and changes in the organisation of vimentin filaments and the attached organelles under the influence of protein kinase C have been reported in other cells. Presumably these changes represent part of the response to ACTH because when protein kinase C is activated by phorbol ester, the cytoskeletal changes necessary for rounding up take place but such changes are not accompanied by increased steroid synthesis. Protein kinase A causes rounding of adrenal cells. and cytoskeletons. This kinase also causes increased cholesterol transport and, hence, stimulation of steroid synthesis. The enzyme also causes phosphorylation of vimentin but with a different cytoskeletal reorganisation from that seen with the other three kinase enzymes. Clearly phosphorylation plays a major role in these responses. Phosphorylation alters the morphology and the functions of the cytoskeleton and this, in turn, is associated with accelerated cholesterol transport. It is now necessary to define the details of the specific phosphorylation reactions that occur during the response to ACTH, that is, which amino acids are phosphorylated and to what extent by each of the kinase enzymes.
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Affiliation(s)
- P F Hall
- Department of Endocrinology, Prince of Wales Hospital, Randwick, NSW, Australia
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40
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Abstract
The rate of steroid synthesis is regulated by the rate of transport of cholesterol to mitochondria. The transport process involves two elements of the cytoskeleton (microfilaments and intermediate filaments) and Ca2+/ calmodulin. Electron microscopy and immunofluorescence reveal that lipid droplets in which steroidogenic cholesterol is stored in the cytoplasm are tightly attached to vimentin intermediate filaments. Mitochondria are also attached to intermediate filaments. Ca2+/calmodulin is known to be essential for the steroidogenic response to ACTH and acts to increase transport of cholesterol to mitochondria. Ca2+/ calmodulin promotes phosphorylation of two important adrenal proteins: vimentin via its protein kinase and myosin light chain via the calmodulin-dependent light-chain kinase. In permeabilized adrenal cells Ca2+/calmodulin causes an ATP-dependent contraction of the cells. Phosphorylation of vimentin is known to cause breakdown of intermediate filaments. Electron microscopy reveals that actin filaments cross-link intermediate filaments in adrenal cells. It is proposed that ACTH has at least two second messengers, Ca2+/calmodulin and cAMP. Ca2+/calmodulin causes breakdown of vimentin filaments and activates a contractile event dependent on ATP and myosin light chain. These changes reorganize the cytoskeleton in such a way as to facilitate the interaction of lipid droplets with mitochondria, resulting in transport of cholesterol to these organelles and hence increased steroid synthesis.
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Affiliation(s)
- P F Hall
- Department of Endocrinology, Prince of Wales Hospital, Sydney, Australia
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Wang SM, Chen JS, Fong TH, Wu JC. Immunocytochemical demonstration of a new vimentin-associated protein in 3T3 fibroblasts. THE HISTOCHEMICAL JOURNAL 1996; 28:469-76. [PMID: 8872136 DOI: 10.1007/bf02331406] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Using a xanthophore cytoskeletal preparation as immunogen, we have produced a monoclonal antibody, A2, which recognized a 160 kDa protein in 3T3 fibroblasts. This protein makes up a cytoplasmic filamentous system, which colocalizes with vimentin filaments. When microtubules and actin filaments are dissolved by high salt extraction, staining with antibody A2 is unaffected. Immunoblot analysis confirms that the 160 kDa protein is co-isolated with vimentin during in vivo high salt extraction. Following vinblastine treatment, both the 160 kDa protein and vimentin become localized to perinuclear caps, as do other intermediate filaments and their associated proteins; after vinblastine removal, the immunostaining produced by A2 becomes filamentous. Immunoelectron microscopy demonstrates that antibody A2 stains a filament system with a diameter of about 10 nm. Our observations suggest that the 160 kDa protein may be a new vimentin-associated protein which differs from the intermediate filament-associated proteins previously reported, and is widely distributed in several cell types.
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Affiliation(s)
- S M Wang
- Department of Anatomy, College of Medicine, National Taiwan University, Taipei
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43
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Plancha CE. Cytokeratin dynamics during oocyte maturation in the hamster requires reaching of metaphase I. Differentiation 1996; 60:87-98. [PMID: 8641549 DOI: 10.1046/j.1432-0436.1996.6020087.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Cytoskeletal components like microfilaments and microtubules are known to play important roles during the processes of oocyte maturation, fertilization and early embryonic development in mammals. However, the roles of other components such as cytoplasmic intermediate filaments, during these critical events remain largely unknown. Oocyte maturation is the final step of oogenesis, immediately before ovulation. Several cytological changes involving the cytoskeleton take place during the maturation process, including meiotic spindle formation, redistribution of cell organelles, membrane polarization and first polar body emission. In this study we determined the organization and rearrangements of cytokeratins during hamster oocyte maturation. Fully grown oocytes were cultured and then visualised using microscopic immunolabelling techniques to monitor the cytokeratin dynamics at specific meiotic stages of the maturation process. In prophase-I-arrested fully grown hamster oocytes, cytokeratins are confined to 4-10 large cortical aggregates, corresponding to extensive meshworks of intermediate filaments. These large aggregates disperse into multiple small spots starting at metaphase I until the end of the maturation period at metaphase II, where cytokeratin exhibits a homogeneously distributed spotted pattern. However, meiotic progression to metaphase II is not necessary for cytokeratin redistribution to occur, since precociously arrested metaphase I oocytes also exhibit dispersed cytoplasmic foci at the end of the culture period. The redistribution of cytokeratins is insensitive to nocodazole and cytochalasin D suggesting it occurs independent of microtubules and microfilaments. In contrast, both cumulus cells and protein synthesis are required for cytokeratin modifications to take place during oocyte maturation. These results show that cytokeratin intermediate filaments are present in the fully grown hamster oocyte, and that a striking reorganization of cytokeratins, triggered by attainment of the metaphase I stage, occurs during maturation.
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Affiliation(s)
- C E Plancha
- Institute of Histology and Embryology, Faculty of Medicine, University of Lisbon, Portugal
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Thoumine O, Ott A, Louvard D. Critical centrifugal forces induce adhesion rupture or structural reorganization in cultured cells. CELL MOTILITY AND THE CYTOSKELETON 1996; 33:276-87. [PMID: 8801033 DOI: 10.1002/(sici)1097-0169(1996)33:4<276::aid-cm4>3.0.co;2-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Cultured epithelial cells were exposed to accelerations ranging from 9,000 to 70,000g for time periods of 5, 15, or 60 min, by centrifugation in a direction tangential to their plastic substrate. Three regimes describe the cellular response: (1) Cell morphology and density remain unaltered at forces below a threshold of about 10(-7) N; (2) Between this critical force and a second threshold of about 1.5 10(-7)N, the number of adherent cells decreases exponentially with time and acceleration, with no alteration of cell morphology. This behavior can be modeled by a constant probability of detaching and by an exponential distribution of cell-to-substrate adhesive forces; (3) Past the second threshold, cells that are still adherent exhibit elongated morphologies, the degree of elongation increasing linearly with the force. The fact that cells lose their vinculin-rich focal contacts past the first threshold and that cells cultured on gelatin-coated plastic show an increased resistance to detachment suggests a rupture of cell-to-substrate adhesions upon centrifugation. Immunofluorescent labeling of cells for actin and tubulin shows a reorganization of the cytoskeleton upon centrifugation, and treatment of cells with the drugs cytochalasin D and nocodazole demonstrates that cytoskeletal elements are actively involved in the structural deformation of cells past the second acceleration threshold, microtubules and microfilaments paying antagonistic roles.
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Affiliation(s)
- O Thoumine
- Section de Recherche, Institut Curie, Paris, France
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45
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Hall PF. The roles of microfilaments and intermediate filaments in the regulation of steroid synthesis. J Steroid Biochem Mol Biol 1995; 55:601-5. [PMID: 8547187 DOI: 10.1016/0960-0760(95)00211-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Much of the cholesterol used in steroid synthesis is stored in lipid droplets in the cytoplasm of steroid-forming cells. The cholesterol ester in these droplets is transported to the inner mitochondrial membrane where it enters the pathway to steroid hormones as free cholesterol--the substrate for the first enzyme, namely P450scc. It has been shown that this transport process governs the rate of steroid synthesis and is specifically stimulated by ACTH and its second messenger. The stimulating influence of ACTH on cholesterol transport is inhibited by cytochalasins, by monospecific anti-actin and by DNase I demonstrating that the steroidogenic cell must possess a pool of monomeric actin available for polymerization to F actin if it is to respond to ACTH and cyclic AMP. It has been shown that the two structures involved in cholesterol transport (droplets and mitochondria) are both bound to vimentin intermediate filaments in adrenal and Leydig cells. In addition these filaments are closely associated with the circumferential actomyosin ring in which they are crosslinked by actin microfilaments. In permeabilized adrenal cells Ca2+/calmodulin phosphorylates vimentin and this change is known to disrupt intermediate filaments and to cause contraction of actomyosin by phosphorylating myosin light chain kinase. Ca2+/calmodulin stimulated cholesterol transport and steroid synthesis and causes rounding of the responding cells by contraction of the actomyosin, if ATP is also added at the same time. Other agents that disrupt intermediate filaments include anti-vimentin plus ATP in permeabilized cells which also results in rounding of the cell. Acrylamide exerts a similar effect in intact adrenal cells and in addition causes rounding of the cells and increase in steroid synthesis without increase in cyclic AMP. It is also known that if adrenal cells are grown on surfaces treated with poly(HEMA), the cells grow in rounded form and steroid synthesis is increased in proportion to the degree of rounding (r = 0.92). This response does not involve increase in cellular levels of cyclic AMP. It is proposed that in vivo where the cell is always round and cannot show more than strictly limited change in shape, ACTH activates Ca2+/calmodulin possibly by redistributing cellular Ca2+. Ca2+/calmodulin in turn promotes phosphorylation of vimentin and myosin light chain. The first of these phosphorylations shortens intermediate filaments and the second promotes contraction of the actomyosin ring with internal shortening and approximation of lipid droplets and mitochondria. Details of the earlier events (activation of Ca2+/calmodulin) and later changes (transfer of cholesterol to the inner membrane) remain to be elucidated. It is clear however that the action of ACTH requires increase in cellular cyclic AMP. These experimental responses bypass this step in the response to ACTH.
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Affiliation(s)
- P F Hall
- Department of Endocrinology, Prince of Wales Hospital, Randwick, NSW, Australia
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46
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Cadrin M, Martinoli MG. Alterations of intermediate filaments in various histopathological conditions. Biochem Cell Biol 1995; 73:627-34. [PMID: 8714682 DOI: 10.1139/o95-069] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Intermediate filament proteins belong to a multigene family and constitute an important cytoskeletal component of most vertebrate cells. Their pattern of expression is tissue specific and is highly controlled during embryonic development. Numerous pathologies are known to be associated with modifications of intermediate filament organisation, although their precise role has not yet been elucidated. The present review focuses on the most recent data concerning the possible causes of intermediate filaments disorganization in specific pathologic conditions affecting the epidermis, the liver, and the nervous system. We discuss the formation of abnormal intermediate filament networks that arise as a consequence of mutations that directly affect intermediate filament structure or are induced by multifactorial causes such as modifications of post-translational processes and changes in the levels of expression.
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Affiliation(s)
- M Cadrin
- Département de chimie-biologie, Université du Québec à Trois-Rivières, QC, Canada
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Ito J, Masuda M, Tada T, Tanaka R. Rapid and gentle extraction, reconstitution and characterization of microfilament and glia filament from rat astrocytes. Neurochem Int 1995; 26:91-7. [PMID: 7787766 DOI: 10.1016/0197-0186(94)00084-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We developed gentle and rapid methods for depolymerization and extraction of both microfilament and glia filament separately from a crude cytoskeletal fraction of rat astrocytes. Electron microscopy revealed that the filament reconstituted from the microfilament extract closely resembled F-actin that was formed from G-actin of rabbit skeletal muscle. It was found by immunoblotting analysis that even the reconstituted microfilament-like filaments, which had been purified by affinity chromatography with heavy meromyosin subfragment 1 (S1)-conjugated Sepharose, contained vimentin and glia fibrillary acidic protein (GFAP) besides actin, inferring the interaction between microfilament and glia filament. The filaments (9-10 nm thick) reconstituted from the glia filament extract were composed of actin and other minor components in addition to vimentin and GFAP. Actin, GFAP, 101, 34, 32.5, 30.5, 29.5 and 28 kDa proteins found in the reconstituted glia filament-like filaments were suggested to be glia filament-associated proteins.
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Affiliation(s)
- J Ito
- Department of Biochemistry, Nagoya City University Medical School, Japan
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48
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Oakley C, Brunette DM. Topographic compensation: guidance and directed locomotion of fibroblasts on grooved micromachined substrata in the absence of microtubules. CELL MOTILITY AND THE CYTOSKELETON 1995; 31:45-58. [PMID: 7553901 DOI: 10.1002/cm.970310106] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Fibroblasts cultured on grooved substrata align themselves and migrate in the direction of the grooves, a phenomenon called contact guidance. Microtubules have been deemed important for cell polarization, directed locomotion, and contact guidance. Because microtubules were the first cytoskeletal element to align with the grooves when fibroblasts spread on grooved substrata, we investigated the consequences of eliminating the influence of microtubules by seeding fibroblasts onto smooth and grooved micromachined substrata in the presence of colcemid. Fibroblasts were examined by time-lapse cinematography and epifluorescence or confocal microscopy to determine cell shape and orientation and the distribution of cytoskeletal or associated elements including actin filaments, vinculin, intermediate filaments, microtubules, and kinesin. As expected, cells spreading on smooth surfaces in the presence of colcemid did not polarize or locomote. Surprisingly however, by 24 hours, cells spread on grooves in the presence of colcemid were morphologically indistinguishable from controls spread on grooves. Both groups were aligned and polarized with the direction of the grooves and demonstrated directional locomotion along the grooves. In the absence of microtubules, kinesin localized to some of the aligned stress fibers and to leading edges of cells spreading on grooves. The grooved substratum compensated for the microtubule deficiency by organizing and maintaining an aligned actin filament framework. Thus, microtubules are not required to establish or maintain stable, polarized cell shapes or directed locomotion, provided an alternate oriented cytoskeletal component is available.
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Affiliation(s)
- C Oakley
- Department of Oral Biology, University of British Columbia, Vancouver, Canada
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Cary RB, Klymkowsky MW, Evans RM, Domingo A, Dent JA, Backhus LE. Vimentin's tail interacts with actin-containing structures in vivo. J Cell Sci 1994; 107 ( Pt 6):1609-22. [PMID: 7962201 DOI: 10.1242/jcs.107.6.1609] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The tail domain of the intermediate filament (IF) protein vimentin is unnecessary for IF assembly in vitro. To study the role of vimentin's tail in vivo, we constructed a plasmid that directs the synthesis of a ‘myc-tagged’ version of the Xenopus vimentin-1 tail domain in bacteria. This polypeptide, mycVimTail, was purified to near homogeneity and injected into cultured Xenopus A6 cells. In these cells the tail polypeptide co-localized with actin even in the presence of cytochalasin. Two myc-tagged control polypeptides argue for the specificity of this interaction. First, a similarly myc-tagged lamin tail domain localizes to the nucleus, indicating that the presence of the myc tag did not itself confer the ability to co-localize with actin (Hennekes and Nigg (1994) J. Cell Sci. 107, 1019–1029). Second, a myc-tagged polypeptide with a molecular mass and net charge at physiological pH (i.e. -4) similar to that of the mycVimTail polypeptide, failed to show any tendency to associate with actin-containing structures, indicating that the interaction between mycVimTail and actin-containing structures was not due to a simple ionic association. Franke (1987; Cell Biol. Int. Rep. 11, 831) noted a similarity in the primary sequence between the tail of the type I keratin DG81A and vimentin. To test whether the DG81A tail interacted with actin-containing structures, we constructed and purified myc-tagged DG81A tail polypeptides. Unexpectedly, these keratin tail polypeptides were largely insoluble under physiological conditions and formed aggregates at the site of injection. While this insolubility made it difficult to determine if they associated with actin-containing structures, it does provide direct evidence that the tails of vimentin and DG81A differ dramatically in their physical properties. Our data suggest that vimentin's tail domain has a highly extended structure, binds to actin-containing structures and may mediate the interaction between vimentin filaments and microfilaments involved in the control of vimentin filament organization (Hollenbeck et al. (1989) J. Cell Sci. 92, 621; Tint et al. (1991) J. Cell Sci. 98, 375).
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Affiliation(s)
- R B Cary
- University of Colorado, Boulder 80309-0347
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50
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Satoh Y, Kashimura M, Kaneko S, Karasaki Y, Higashi K, Gotoh S. Cloning of cDNAs with possible association with senescence and immortalization of human cells. Mutat Res 1994; 316:25-36. [PMID: 7507566 DOI: 10.1016/0921-8734(94)90005-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Normal human diploid fibroblasts (HDF) have a finite life span in vitro and have been used as a model system for the study of in vivo aging. Little is known about how changes in gene expression may affect the immortalization of human fibroblasts. We looked for cDNA clones whose mRNAs were differentially expressed between mortal senescent SV40-transformed human fibroblasts (B-32) and the immortal counterparts (B-32F) derived from B-32 cells. We identified three cDNA isolates by subtractive differential hybridization with 32P-labeled cDNA probes from B-32 cells and B-32F cells. Nucleotide sequence analysis of these cDNA clones revealed that they were homologous to the human vimentin, a human mitochondrial gene and a human gene of unknown nature. Slot blot and Northern blot analyses demonstrated that the former two were preferentially expressed in senescent B-32 cells and the last one was less expressed in B-32F immortal cells.
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Affiliation(s)
- Y Satoh
- Department of Obstetrics and Gynecology, University of Occupational and Environmental Health, Kitakyushu City, Japan
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