DOCSLIB.ORG

Intermediate Filaments and Their Associated Proteins

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Intermediate Filaments and Their Associated Proteins 93 Intermediate ®laments and their associated proteins: multiple dynamic personalities Megan K Houseweart∗ and Don W Cleveland² A fusion of mouse and human genetics has now proven that regulated by phosphorylation, the recent identi®cation of intermediate ®laments form a ¯exible scaffold essential for several kinases involved strengthens the argument that structuring cytoplasm in a variety of cell contexts. In some these dynamics are true in vivo events. The growing cases, the formation of this scaffold is achieved through a list of intermediate-®lament-associated proteins (IFAPs) newly identi®ed family of intermediate-®lament-associated surely expands the repertoire of possible interactions proteins that form cross-bridges between intermediate permitted to IFs and may also add another layer of ®laments and other cytoskeletal elements, including actin and regulatory complexity. Indeed, the discovery of several microtubules. human and mouse diseases caused by mutations in the IFAP proteins plectin and neuronal bullous pemphigoid antigen (BPAG1n) illustrates the importance of these Addresses molecules in providing links between components of the ∗Ludwig Institute for Cancer Research and Division of Cellular and Molecular Medicine, University of California at San Diego, 9500 cellular cytoskeleton. Most would agree that intermediate Gilman Drive, La Jolla, CA 92093, USA ®laments can no longer be thought of as the least dynamic ²Ludwig Institute for Cancer Research, Division of Cellular and components of the cell cytoskeleton. This review focuses Molecular Medicine, and Department of Medicine and Neuroscience, on the recent advances in understanding IFs and their University of California at San Diego, 9500 Gilman Drive, La Jolla, CA associated proteins. 92093, USA; e-mail: [email protected] Current Opinion in Cell Biology 1998, 10:93±101 A growing family of vital intermediate http://biomednet.com/elecref/0955067401000093 ®lament cross-linkers Current Biology Ltd ISSN 0955-0674 Perhaps the most exciting new development in the IF ®eld has been the recognition that IFs have binding Abbreviations partners and that these partners that have important ALS amyotrophic lateral sclerosis BPAG bullous pemphigoid antigen functions in structuring the three-dimensional cytoplasm. GFAP glial ®brillary acidic protein The IF-associated proteins, or IFAPs as they have come IF intermediate ®lament to be called, are steadily gaining attention as more diseases IFAP IF-associated protein in humans and mice are shown to arise from mutations MD-EBS muscular dystrophy with epidermolysis bullosa NF neuro®lament in these proteins. The ability of IFAPs to link various NLS nuclear localization signal components of the cytoskeleton in many different cell SOD1 superoxide dismutase 1 types suggests several potential functions as dynamic regulators of cytoskeletal assembly and maintainers of IF network integrity. Support for this notion came recently Introduction from studies that utilized peptides corresponding to Intermediate ®laments (IFs) have long been thought a conserved helix region of IF proteins that, when of as ®xed structural bystanders around whom the injected into ®broblast cells, disrupted the IF, microtubule, •• lively activity of the cell is distributed. More recently, and micro®lament networks [1 ]. The authors proposed however, IFs and their associated proteins have been that the introduced peptides effectively competed for ®rmly established as constituents of deformable cellular IFAPs that would normally link the ®lament networks latticeworks, imparting integrity and strength to tissues together and in this way caused the rapid disassembly throughout the body. Long known to extend throughout of the cytoskeleton. Currently, the list of IFAPs includes the cytoplasm, possibly positioning the nucleus within the members that interact with IFs from all ®ve IF subtypes, cell, IF networks have been shown to reversibly link the but as new IFs (including the lens-speci®c beaded • plasma membrane to other cytoskeletal components to ®laments [2 ]) are identi®ed, the discovery of new linking modulate cell shape and confer resistance to mechanical partners will surely follow. stress. As dynamic components of the cytoplasmic and nuclear cytoskeletons, IFs are thought to contribute to Plectin: an essential linker between intermediate cellular structural rearrangements that occur during cell ®laments, microtubules, myosin, and actin division. Evidence for pools of soluble IF subunits that can One of the most thoroughly characterized IFAPs is plectin, exchange along the entire length of assembled ®laments an abundant and extremely large (>500 kDa) cytoskeletal has grown and now helps to explain the basis for the cross-linker. Plectin is expressed in many cell types and rapid changes in IF organization that observed in response was initially shown by solid phase binding analysis to to such stimuli as heat shock and application of growth interact with a wide variety of other proteins such as factors. As many examples of IF dynamics appear to be vimentin, glial ®brillary acidic protein, keratins, lamin B, 94 Cytoskeleton microtubule-associated proteins, α-spectrin, and all three attachment of epidermal cells to the basement membrane. neuro®lament proteins [3,4]. More recently, immunoelec- That the strength provided by plectin is an essential tron microscopy studies [5••] to evaluate plectin-binding feature of cellular architecture has been demonstrated by interactions revealed that a) plectin forms cross-bridges the recent discovery of mutations in the gene for plectin between IFs and microtubules, b) vimentin ®laments are as a cause of the human disease muscular dystrophy decorated with plectin projections, c) plectin links IFs with epidermolysis bullosa (MD-EBS) [13••±15••]. This and actin ®lament bundles, and d) plectin associates with inherited disease is characterized by muscle degeneration myosin ®laments in cultured cells. The extraordinarily and skin blistering due to a failure to anchor the cellular IF clear images of plectin cross-bridges between various network to the plasma membrane via hemidesmosomes. ®lament networks supports many of the previously Three of the four known mutations, an eight base postulated plectin interactions and is further corroborated pair insertion [13••], an eight base pair deletion [14••], by biochemical and domain sequence data. Inspection of and a single nucleotide deletion [15••], occur within the rat and human plectin sequences has demonstrated the same region of plectin and result in premature the existence of a putative amino-terminal actin-binding termination approximately one third of the way through domain [6]. the >500 kDa polypeptide. The fourth known mutation, a nine nucleotide deletion [15••], removes three amino acids Sequence inspection and mutagenesis studies have mapped from within a 23 amino acid stretch that was shown to be a nuclear localization signal (NLS) within plectin's carboxy- identical between human and rat plectin. terminal vimentin binding domain motif [7••]. Beyond its role as a versatile cross-linker in interphase, the Tissues from patients harboring the three truncation presence of a plectin NLS [6], the fact that plectin mutations are typically devoid of plectin, whereas the binds lamin B in vitro [4], and the established pattern fourth mutation apparently encodes an otherwise full of plectin disassociation from vimentin upon entry into length protein and results in reduced plectin levels. mitosis [8•] suggest several possible roles for plectin during Patients with any of the four mutations typically display cell division. One scenario predicts that separating from reduced levels of BPAG1e, muscle ®ber abnormalities, cytoplasmic IFs would free plectin and collapse the IF and hemidesmosomes without an inner attachment plate network into the typical cagelike IF structure seen during [13••±15••]. mitosis. Thus freed, the uncovered plectin NLS could sequester NLS binding proteins. Alternatively, plectin's In order to determine more directly which aspects association with lamin B may act to disassemble the of plectin cross-linking activities are essential in vivo, nuclear matrix during nuclear envelope breakdown, or transgenic mice were engineered that lack the plectin perhaps the interaction really functions in the opposite protein [16••]. These plectin-null mice die two to three manner, that is, to promote nuclear reassembly (as argued days after birth and display pathological features typical in detail [9]). Although these ideas are as yet only of MD-EBS, with a few notable differences. For example, speculative, the protein kinase p34cdc2 has been shown the keratinocytes of MD-EBS skin rupture at the basal to phosphorylate plectin and cause its dissociation from hemidesmosome level, whereas the keratinocytes of vimentin during mitosis [8•]. Similarly, phosphorylation plectin-null mice rupture at all levels and contain ul- of plectin by protein kinase A or C can inhibit the trastructurally normal hemidesmosomes and desmosomes. binding of plectin to lamin B [4], providing the means by Plectin-de®cient skeletal muscle cells in mice were often which plectin could accomplish the mitosis-speci®c roles necrotic and disrupted sarcomeres were prevalent, whereas proposed above. cardiomyocytes displayed abnormally arranged sarcomeres and disintegrating intercalated discs. Additionally, the Comparison of plectin's structural domains with those distribution and expression levels of selected cytoskeletal
Load more

Recommended publications
  • The Desmoplakin Carboxyl Terminus Coaligns with and Specifically Disrupts Intermediate Filament Networks When Expressed in Cultured Cells Thaddeus S
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by PubMed Central The Desmoplakin Carboxyl Terminus Coaligns with and Specifically Disrupts Intermediate Filament Networks When Expressed in Cultured Cells Thaddeus S. Stappenbeck and Kathleen J. Green Department of Pathology and the Cancer Center, Northwestern University Medical School, Chicago, Illinois 60611 Abstract. Specific interactions between desmoplakins tides including the 90-kD carboxy-terminal globular I and 11 (DP I and II) and other desmosomal or cyto- domain of DP I specifically colocalized with and ulti- skeletal molecules have been difficult to determine in mately resulted in the complete disruption of IF in part because of the complexity and insolubility of the both cell lines. This effect was specific for IF as micro- desmosome and its constituents . We have used a mo- tubule and microfilament networks were unaltered . lecular genetic approach to investigate the role that This effect was also specific for the carboxyl terminus DP I and 11 may play in the association of the desmo- of DP, as the expression of the 95-kD rod domain of somal plaque with cytoplasmic intermediate filaments DP I did not visibly alter IF networks. Immunogold (IF) . A series of mammalian expression vectors en- localization of COS-7 cells transfected with constructs coding specific predicted domains of DP I were tran- including the carboxyl terminus of DP demonstrated siently expressed in cultured cells that form (COS-7) an accumulation of mutant protein in perinuclear aggre- and do not form (NIH-3T3) desmosomes. Sequence gates within which IF subunits were sequestered.
    [Show full text]
  • A Cell Line P53 Mutation Type UM
    A Cell line p53 mutation Type UM-SCC 1 wt UM-SCC5 Exon 5, 157 GTC --> TTC Missense mutation by transversion (Valine --> Phenylalanine UM-SCC6 wt UM-SCC9 wt UM-SCC11A wt UM-SCC11B Exon 7, 242 TGC --> TCC Missense mutation by transversion (Cysteine --> Serine) UM-SCC22A Exon 6, 220 TAT --> TGT Missense mutation by transition (Tyrosine --> Cysteine) UM-SCC22B Exon 6, 220 TAT --> TGT Missense mutation by transition (Tyrosine --> Cysteine) UM-SCC38 Exon 5, 132 AAG --> AAT Missense mutation by transversion (Lysine --> Asparagine) UM-SCC46 Exon 8, 278 CCT --> CGT Missense mutation by transversion (Proline --> Alanine) B 1 Supplementary Methods Cell Lines and Cell Culture A panel of ten established HNSCC cell lines from the University of Michigan series (UM-SCC) was obtained from Dr. T. E. Carey at the University of Michigan, Ann Arbor, MI. The UM-SCC cell lines were derived from eight patients with SCC of the upper aerodigestive tract (supplemental Table 1). Patient age at tumor diagnosis ranged from 37 to 72 years. The cell lines selected were obtained from patients with stage I-IV tumors, distributed among oral, pharyngeal and laryngeal sites. All the patients had aggressive disease, with early recurrence and death within two years of therapy. Cell lines established from single isolates of a patient specimen are designated by a numeric designation, and where isolates from two time points or anatomical sites were obtained, the designation includes an alphabetical suffix (i.e., "A" or "B"). The cell lines were maintained in Eagle's minimal essential media supplemented with 10% fetal bovine serum and penicillin/streptomycin.
    [Show full text]
  • The Spectraplakin Dystonin Antagonizes YAP Activity and Suppresses Tumourigenesis Praachi B
    www.nature.com/scientificreports OPEN The spectraplakin Dystonin antagonizes YAP activity and suppresses tumourigenesis Praachi B. Jain1,2,3, Patrícia S. Guerreiro1,2,3, Sara Canato1,2,3 & Florence Janody 1,2,3* Aberrant expression of the Spectraplakin Dystonin (DST) has been observed in various cancers, including those of the breast. However, little is known about its role in carcinogenesis. In this report, we demonstrate that Dystonin is a candidate tumour suppressor in breast cancer and provide an underlying molecular mechanism. We show that in MCF10A cells, Dystonin is necessary to restrain cell growth, anchorage-independent growth, self-renewal properties and resistance to doxorubicin. Strikingly, while Dystonin maintains focal adhesion integrity, promotes cell spreading and cell-substratum adhesion, it prevents Zyxin accumulation, stabilizes LATS and restricts YAP activation. Moreover, treating DST- depleted MCF10A cells with the YAP inhibitor Verteporfn prevents their growth. In vivo, the Drosophila Dystonin Short stop also restricts tissue growth by limiting Yorkie activity. As the two Dystonin isoforms BPAG1eA and BPAG1e are necessary to inhibit the acquisition of transformed features and are both downregulated in breast tumour samples and in MCF10A cells with conditional induction of the Src proto-oncogene, they could function as the predominant Dystonin tumour suppressor variants in breast epithelial cells. Thus, their loss could deem as promising prognostic biomarkers for breast cancer. Breast cancer progression depends on cell autonomous regulatory mechanisms, driven by mutations and epi- genetic changes, and on non-cell autonomous interactions with the surrounding tumour microenvironment1,2. During this multistep process, normal breast epithelial cells acquire various cellular properties arising from dereg- ulated cellular signalling3,4.
    [Show full text]
  • Drp1 Overexpression Induces Desmin Disassembling and Drives Kinesin-1 Activation Promoting Mitochondrial Trafficking in Skeletal Muscle
    Cell Death & Differentiation (2020) 27:2383–2401 https://doi.org/10.1038/s41418-020-0510-7 ARTICLE Drp1 overexpression induces desmin disassembling and drives kinesin-1 activation promoting mitochondrial trafficking in skeletal muscle 1 1 2 2 2 3 Matteo Giovarelli ● Silvia Zecchini ● Emanuele Martini ● Massimiliano Garrè ● Sara Barozzi ● Michela Ripolone ● 3 1 4 1 5 Laura Napoli ● Marco Coazzoli ● Chiara Vantaggiato ● Paulina Roux-Biejat ● Davide Cervia ● 1 1 2 1,4 6 Claudia Moscheni ● Cristiana Perrotta ● Dario Parazzoli ● Emilio Clementi ● Clara De Palma Received: 1 August 2019 / Revised: 13 December 2019 / Accepted: 23 January 2020 / Published online: 10 February 2020 © The Author(s) 2020. This article is published with open access Abstract Mitochondria change distribution across cells following a variety of pathophysiological stimuli. The mechanisms presiding over this redistribution are yet undefined. In a murine model overexpressing Drp1 specifically in skeletal muscle, we find marked mitochondria repositioning in muscle fibres and we demonstrate that Drp1 is involved in this process. Drp1 binds KLC1 and enhances microtubule-dependent transport of mitochondria. Drp1-KLC1 coupling triggers the displacement of KIF5B from 1234567890();,: 1234567890();,: kinesin-1 complex increasing its binding to microtubule tracks and mitochondrial transport. High levels of Drp1 exacerbate this mechanism leading to the repositioning of mitochondria closer to nuclei. The reduction of Drp1 levels decreases kinesin-1 activation and induces the partial recovery of mitochondrial distribution. Drp1 overexpression is also associated with higher cyclin-dependent kinase-1 (Cdk-1) activation that promotes the persistent phosphorylation of desmin at Ser-31 and its disassembling. Fission inhibition has a positive effect on desmin Ser-31 phosphorylation, regardless of Cdk-1 activation, suggesting that induction of both fission and Cdk-1 are required for desmin collapse.
    [Show full text]
  • Plakoglobin Is Required for Effective Intermediate Filament Anchorage to Desmosomes Devrim Acehan1, Christopher Petzold1, Iwona Gumper2, David D
    ORIGINAL ARTICLE Plakoglobin Is Required for Effective Intermediate Filament Anchorage to Desmosomes Devrim Acehan1, Christopher Petzold1, Iwona Gumper2, David D. Sabatini2, Eliane J. Mu¨ller3, Pamela Cowin2,4 and David L. Stokes1,2,5 Desmosomes are adhesive junctions that provide mechanical coupling between cells. Plakoglobin (PG) is a major component of the intracellular plaque that serves to connect transmembrane elements to the cytoskeleton. We have used electron tomography and immunolabeling to investigate the consequences of PG knockout on the molecular architecture of the intracellular plaque in cultured keratinocytes. Although knockout keratinocytes form substantial numbers of desmosome-like junctions and have a relatively normal intercellular distribution of desmosomal cadherins, their cytoplasmic plaques are sparse and anchoring of intermediate filaments is defective. In the knockout, b-catenin appears to substitute for PG in the clustering of cadherins, but is unable to recruit normal levels of plakophilin-1 and desmoplakin to the plaque. By comparing tomograms of wild type and knockout desmosomes, we have assigned particular densities to desmoplakin and described their interaction with intermediate filaments. Desmoplakin molecules are more extended in wild type than knockout desmosomes, as if intermediate filament connections produced tension within the plaque. On the basis of our observations, we propose a particular assembly sequence, beginning with cadherin clustering within the plasma membrane, followed by recruitment of plakophilin and desmoplakin to the plaque, and ending with anchoring of intermediate filaments, which represents the key to adhesive strength. Journal of Investigative Dermatology (2008) 128, 2665–2675; doi:10.1038/jid.2008.141; published online 22 May 2008 INTRODUCTION dense plaque that is further from the membrane and that Desmosomes are large macromolecular complexes that mediates the binding of intermediate filaments.
    [Show full text]
  • Transiently Structured Head Domains Control Intermediate Filament Assembly
    Transiently structured head domains control intermediate filament assembly Xiaoming Zhoua, Yi Lina,1, Masato Katoa,b,c, Eiichiro Morid, Glen Liszczaka, Lillian Sutherlanda, Vasiliy O. Sysoeva, Dylan T. Murraye, Robert Tyckoc, and Steven L. McKnighta,2 aDepartment of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390; bInstitute for Quantum Life Science, National Institutes for Quantum and Radiological Science and Technology, 263-8555 Chiba, Japan; cLaboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520; dDepartment of Future Basic Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, Japan; and eDepartment of Chemistry, University of California, Davis, CA 95616 Contributed by Steven L. McKnight, January 2, 2021 (sent for review October 30, 2020; reviewed by Lynette Cegelski, Tatyana Polenova, and Natasha Snider) Low complexity (LC) head domains 92 and 108 residues in length are, IF head domains might facilitate filament assembly in a manner respectively, required for assembly of neurofilament light (NFL) and analogous to LC domain function by RNA-binding proteins in the desmin intermediate filaments (IFs). As studied in isolation, these IF assembly of RNA granules. head domains interconvert between states of conformational disor- IFs are defined by centrally located α-helical segments 300 to der and labile, β-strand–enriched polymers. Solid-state NMR (ss-NMR) 350 residues in length. These central, α-helical segments are spectroscopic studies of NFL and desmin head domain polymers re- flanked on either end by head and tail domains thought to be veal spectral patterns consistent with structural order.
    [Show full text]
  • Analysis of Mouse Keratin 6A Regulatory Sequences in Transgenic Mice Reveals Constitutive, Tissue-Speci®C Expression by a Keratin 6A Minigene
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Analysis of Mouse Keratin 6a Regulatory Sequences in Transgenic Mice Reveals Constitutive, Tissue-Speci®c Expression by a Keratin 6a Minigene Donna Mahony, Seetha Karunaratne, Graham Cam,* and Joseph A. Rothnagel Department of Biochemistry and the Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland, and *Division of Animal Production, CSIRO, Blacktown, New South Wales, Australia The analysis of keratin 6 expression is complicated atin 6 expressing tissues, including the hair follicle, by the presence of multiple isoforms that are tongue, footpad, and nail bed, showing that both expressed constitutively in a number of internal stra- transgenes retained keratinocyte-speci®c expression. ti®ed epithelia, in palmoplantar epidermis, and in Quantitative analysis of b-galactosidase activity veri- the companion cell layer of the hair follicle. In addi- ®ed that both the 1.3 and 0.12 kb keratin 6a promo- tion, keratin 6 expression is inducible in interfollicu- ter constructs produced similar levels of the reporter. lar epidermis and the outer root sheath of the Notably, bothconstructs were constitutively follicle, in response to wounding stimuli, phorbol expressed in the outer root sheath and interfollicular esters, or retinoic acid. In order to establishthecriti- epidermis in the absence of any activating stimulus, cal regions involved in the regulation of keratin 6a suggesting that they lack the regulatory elements (the dominant isoform in mice), we generated trans- that normally silence transcription in these cells. This genic mice withtwo different-sized mouse keratin 6a study has revealed that a keratin 6a minigene con- constructs containing either 1.3 kb or 0.12 kb of 5¢ tains critical cis elements that mediate tissue-speci®c ¯anking sequence linked to the lacZ reporter gene.
    [Show full text]
  • Structural and Biochemical Changes Underlying a Keratoderma-Like Phenotype in Mice Lacking Suprabasal AP1 Transcription Factor Function
    Citation: Cell Death and Disease (2015) 6, e1647; doi:10.1038/cddis.2015.21 OPEN & 2015 Macmillan Publishers Limited All rights reserved 2041-4889/15 www.nature.com/cddis Structural and biochemical changes underlying a keratoderma-like phenotype in mice lacking suprabasal AP1 transcription factor function EA Rorke*,1, G Adhikary2, CA Young2, RH Rice3, PM Elias4, D Crumrine4, J Meyer4, M Blumenberg5 and RL Eckert2,6,7,8 Epidermal keratinocyte differentiation on the body surface is a carefully choreographed process that leads to assembly of a barrier that is essential for life. Perturbation of keratinocyte differentiation leads to disease. Activator protein 1 (AP1) transcription factors are key controllers of this process. We have shown that inhibiting AP1 transcription factor activity in the suprabasal murine epidermis, by expression of dominant-negative c-jun (TAM67), produces a phenotype type that resembles human keratoderma. However, little is understood regarding the structural and molecular changes that drive this phenotype. In the present study we show that TAM67-positive epidermis displays altered cornified envelope, filaggrin-type keratohyalin granule, keratin filament, desmosome formation and lamellar body secretion leading to reduced barrier integrity. To understand the molecular changes underlying this process, we performed proteomic and RNA array analysis. Proteomic study of the corneocyte cross-linked proteome reveals a reduction in incorporation of cutaneous keratins, filaggrin, filaggrin2, late cornified envelope precursor proteins, hair keratins and hair keratin-associated proteins. This is coupled with increased incorporation of desmosome linker, small proline-rich, S100, transglutaminase and inflammation-associated proteins. Incorporation of most cutaneous keratins (Krt1, Krt5 and Krt10) is reduced, but incorporation of hyperproliferation-associated epidermal keratins (Krt6a, Krt6b and Krt16) is increased.
    [Show full text]
  • Intermediate Filament Accumulation Can Stabilize Microtubules in Caenorhabditis Elegans Motor Neurons
    Intermediate filament accumulation can stabilize microtubules in Caenorhabditis elegans motor neurons Naina Kurupa, Yunbo Lia, Alexandr Goncharova, and Yishi Jina,b,1 aNeurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093; and bDepartment of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093 Edited by H. Robert Horvitz, Massachusetts Institute of Technology, Cambridge, MA, and approved February 11, 2018 (received for review December 21, 2017) Neural circuits utilize a coordinated cellular machinery to form and Results eliminate synaptic connections, with the neuronal cytoskeleton Identification of IF Genes That Regulate Synapse Rewiring. At the playing a prominent role. During larval development of Caenorhabditis end of larval stage 1 (L1), the dorsal D (DD)-type motor neurons elegans, synapses of motor neurons are stereotypically rewired rewire their presynaptic connections from the ventral nerve cord through a process facilitated by dynamic microtubules (MTs). Through a (VNC) to the dorsal nerve cord (DNC), concurrent with the genetic suppressor screen on mutant animals that fail to rewire synap- birth of ventral D (VD)-type motor neurons, which then form ses, and in combination with live imaging and ultrastructural studies, synapses along the VNC (19). We visualized DD-neuron pre- we find that intermediate filaments (IFs) stabilize MTs to prevent syn- synaptic terminals using a GFP-tagged synaptobrevin (SNB- apse rewiring. Genetic ablation of IFs or pharmacological disruption of 1::GFP) reporter (juIs137:Pflp-13 SNB-1::GFP). In L1 animals, IF networks restores MT growth and rescues synapse rewiring defects discrete synaptic puncta were present along the ventral neurites in the mutant animals, indicating that IF accumulation directly alters MT (18), but in late larvae and adults, synaptic puncta were only seen stability.
    [Show full text]
  • The Relationship Between Intermediate Filaments and Microfilaments Before and During the Formation of Desmosomes and Adherens-Ty
    Published May 1, 1987 The Relationship between Intermediate Filaments and Microfilaments before and during the Formation of Desmosomes and Adherens-type Junctions in Mouse Epidermal Keratinocytes Kathleen J. Green, Benjamin Geiger,* Jonathan C. R. Jones, John C. Talian, and Robert D. Goldman Department of Cell Biology and Anatomy, Northwestern University Medical School, Chicago, Illinois 60611; and * Department of Chemical Immunology, The Weizmann Institute of Science, Rehovot, Israel Abstract. Actin, keratin, vinculin and desmoplakin ermost of the concentric MFB. Individual IF often organization were studied in primary mouse keratino- splay out, becoming interwoven into these MFB in the cytes before and during Ca2+-induced cell contact forma- region of cell-substrate contact. In the first 30 min af- tion. Double-label fluorescence shows that in cells cul- ter the Ca 2+ switch, areas of submembranous dense Downloaded from tured in low Ca 2÷ medium, keratin-containing inter- material (identified as adherens junctions), which are mediate filament bundles (IFB) and desmoplakin- associated with the perpendicular MFB, can be seen at containing spots are both concentrated towards the cell newly formed cell-ceU contact sites. By 1-2 h, IFB- center in a region bounded by a series of concentric desmosomal component complexes are aligned with microfilament bundles (MFB). Within 5-30 min after the perpendicular MFB as the complexes become jcb.rupress.org raising Ca 2+ levels, a discontinuous actin/vinculin-rich, redistributed to cell-cell interfaces. Cytochalasin D submembranous zone of fluorescence appears at cell- treatment causes the redistribution of actin into numer- cell interfaces. This zone is usually associated with ous patches; keratin-containing Lr:B undergo a con- short, perpendicular MFB, which become wider and comitant redistribution, forming foci that coincide with longer with time.
    [Show full text]
  • Proteomic Expression Profile in Human Temporomandibular Joint
    diagnostics Article Proteomic Expression Profile in Human Temporomandibular Joint Dysfunction Andrea Duarte Doetzer 1,*, Roberto Hirochi Herai 1 , Marília Afonso Rabelo Buzalaf 2 and Paula Cristina Trevilatto 1 1 Graduate Program in Health Sciences, School of Medicine, Pontifícia Universidade Católica do Paraná (PUCPR), Curitiba 80215-901, Brazil; [email protected] (R.H.H.); [email protected] (P.C.T.) 2 Department of Biological Sciences, Bauru School of Dentistry, University of São Paulo, Bauru 17012-901, Brazil; [email protected] * Correspondence: [email protected]; Tel.: +55-41-991-864-747 Abstract: Temporomandibular joint dysfunction (TMD) is a multifactorial condition that impairs human’s health and quality of life. Its etiology is still a challenge due to its complex development and the great number of different conditions it comprises. One of the most common forms of TMD is anterior disc displacement without reduction (DDWoR) and other TMDs with distinct origins are condylar hyperplasia (CH) and mandibular dislocation (MD). Thus, the aim of this study is to identify the protein expression profile of synovial fluid and the temporomandibular joint disc of patients diagnosed with DDWoR, CH and MD. Synovial fluid and a fraction of the temporomandibular joint disc were collected from nine patients diagnosed with DDWoR (n = 3), CH (n = 4) and MD (n = 2). Samples were subjected to label-free nLC-MS/MS for proteomic data extraction, and then bioinformatics analysis were conducted for protein identification and functional annotation. The three Citation: Doetzer, A.D.; Herai, R.H.; TMD conditions showed different protein expression profiles, and novel proteins were identified Buzalaf, M.A.R.; Trevilatto, P.C.
    [Show full text]
  • Gene Expression Signatures and Biomarkers of Noninvasive And
    Oncogene (2006) 25, 2328–2338 & 2006 Nature Publishing Group All rights reserved 0950-9232/06 $30.00 www.nature.com/onc ORIGINAL ARTICLE Gene expression signatures and biomarkers of noninvasive and invasive breast cancer cells: comprehensive profiles by representational difference analysis, microarrays and proteomics GM Nagaraja1, M Othman2, BP Fox1, R Alsaber1, CM Pellegrino3, Y Zeng2, R Khanna2, P Tamburini3, A Swaroop2 and RP Kandpal1 1Department of Biological Sciences, Fordham University, Bronx, NY, USA; 2Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, USA and 3Bayer Corporation, West Haven, CT, USA We have characterized comprehensive transcript and Keywords: representational difference analysis; micro- proteomic profiles of cell lines corresponding to normal arrays; proteomics; breast carcinoma; biomarkers; breast (MCF10A), noninvasive breast cancer (MCF7) and copper homeostasis invasive breast cancer (MDA-MB-231). The transcript profiles were first analysed by a modified protocol for representational difference analysis (RDA) of cDNAs between MCF7 and MDA-MB-231 cells. The majority of genes identified by RDA showed nearly complete con- Introduction cordance withmicroarray results, and also led to the identification of some differentially expressed genes such The transformation of a normal cell into a cancer cell as lysyl oxidase, copper transporter ATP7A, EphB6, has been correlated to altered expression of a variety of RUNX2 and a variant of RUNX2. The altered transcripts genes (Perou et al., 2000; Becker et al., 2005). The identified by microarray analysis were involved in cell–cell expression of some of these genes is a direct result of or cell–matrix interaction, Rho signaling, calcium home- sequence mutation, whereas other changes occur due to ostasis and copper-binding/sensitive activities.
    [Show full text]