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Berry CW, Fuller MT. Functional septate junctions between cyst cells are required for survival of transit amplifying male germ cells expressing Bag of marbles. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.02.587826. [PMID: 38617328 PMCID: PMC11014526 DOI: 10.1101/2024.04.02.587826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
In adult stem cell lineages, the cellular microenvironment plays essential roles to ensure the proper balance of self-renewal, differentiation and regulated elimination of differentiating cells. Although regulated death of progenitor cells undergoing proliferation or early differentiation is a feature of many tissues, mechanisms that initiate this pruning remain unexplored, particularly in the male germline, where up to 30% of the germline is eliminated before the meiotic divisions. We conducted a targeted screen to identify functional regulators required in somatic support cells for survival or differentiation at early steps in the male germ line stem cell lineage. Cell type-specific knockdown in cyst cells uncovered novel roles of genes in germline stem cell differentiation, including a previously unappreciated role of the Septate Junction (SJ) in preventing cell death of differentiating germline progenitors. Loss of the SJ in the somatic cyst cells resulted in elimination of transit-amplifying spermatogonia by the 8-cell stage. Germ cell death was spared in males mutant for the differentiation factor bam indicating that intact barriers surrounding transit amplifying progenitors are required to ensure germline survival once differentiation has initiated.
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Affiliation(s)
- Cameron W. Berry
- Department of Developmental Biology, Stanford University School of Medicine, USA
| | - Margaret T. Fuller
- Department of Developmental Biology, Stanford University School of Medicine, USA
- Department of Genetics, Stanford University School of Medicine, USA
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2
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Bhattacharya M, Starz-Gaiano M. Steroid hormone signaling synchronizes cell migration machinery, adhesion and polarity to direct collective movement. J Cell Sci 2024; 137:jcs261164. [PMID: 38323986 DOI: 10.1242/jcs.261164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 01/23/2024] [Indexed: 02/08/2024] Open
Abstract
Migratory cells - either individually or in cohesive groups - are critical for spatiotemporally regulated processes such as embryonic development and wound healing. Their dysregulation is the underlying cause of formidable health problems such as congenital abnormalities and metastatic cancers. Border cell behavior during Drosophila oogenesis provides an effective model to study temporally regulated, collective cell migration in vivo. Developmental timing in flies is primarily controlled by the steroid hormone ecdysone, which acts through a well-conserved, nuclear hormone receptor complex. Ecdysone signaling determines the timing of border cell migration, but the molecular mechanisms governing this remain obscure. We found that border cell clusters expressing a dominant-negative form of ecdysone receptor extended ineffective protrusions. Additionally, these clusters had aberrant spatial distributions of E-cadherin (E-cad), apical domain markers and activated myosin that did not overlap. Remediating their expression or activity individually in clusters mutant for ecdysone signaling did not restore proper migration. We propose that ecdysone signaling synchronizes the functional distribution of E-cadherin, atypical protein kinase C (aPKC), Discs large (Dlg1) and activated myosin post-transcriptionally to coordinate adhesion, polarity and contractility and temporally control collective cell migration.
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Affiliation(s)
- Mallika Bhattacharya
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - Michelle Starz-Gaiano
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
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3
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Esmangart de Bournonville T, Jaglarz MK, Durel E, Le Borgne R. ESCRT-III-dependent adhesive and mechanical changes are triggered by a mechanism detecting alteration of septate junction integrity in Drosophila epithelial cells. eLife 2024; 13:e91246. [PMID: 38305711 PMCID: PMC10959524 DOI: 10.7554/elife.91246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 02/01/2024] [Indexed: 02/03/2024] Open
Abstract
Barrier functions of proliferative epithelia are constantly challenged by mechanical and chemical constraints. How epithelia respond to and cope with disturbances of barrier functions to allow tissue integrity maintenance is poorly characterised. Cellular junctions play an important role in this process and intracellular traffic contribute to their homeostasis. Here, we reveal that, in Drosophila pupal notum, alteration of the bi- or tricellular septate junctions (SJs) triggers a mechanism with two prominent outcomes. On one hand, there is an increase in the levels of E-cadherin, F-actin, and non-muscle myosin II in the plane of adherens junctions. On the other hand, β-integrin/Vinculin-positive cell contacts are reinforced along the lateral and basal membranes. We found that the weakening of SJ integrity, caused by the depletion of bi- or tricellular SJ components, alters ESCRT-III/Vps32/Shrub distribution, reduces degradation and instead favours recycling of SJ components, an effect that extends to other recycled transmembrane protein cargoes including Crumbs, its effector β-Heavy Spectrin Karst, and β-integrin. We propose a mechanism by which epithelial cells, upon sensing alterations of the SJ, reroute the function of Shrub to adjust the balance of degradation/recycling of junctional cargoes and thereby compensate for barrier junction defects to maintain epithelial integrity.
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Affiliation(s)
- Thomas Esmangart de Bournonville
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) – UMR 6290RennesFrance
- Global Health Institute, School of Life Science, Ecole Polytechnique Fédérale de Lausanne (EPFL)LausanneSwitzerland
| | - Mariusz K Jaglarz
- Department of Developmental Biology and Invertebrate Morphology, Institute of Zoology and Biomedical Research, Jagiellonian University in KrakowKrakowPoland
| | - Emeline Durel
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) – UMR 6290RennesFrance
| | - Roland Le Borgne
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) – UMR 6290RennesFrance
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4
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Mira-Osuna M, Borgne RL. Assembly, dynamics and remodeling of epithelial cell junctions throughout development. Development 2024; 151:dev201086. [PMID: 38205947 DOI: 10.1242/dev.201086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Cell junctions play key roles in epithelial integrity. During development, when epithelia undergo extensive morphogenesis, these junctions must be remodeled in order to maintain mechanochemical barriers and ensure the cohesion of the tissue. In this Review, we present a comprehensive and integrated description of junctional remodeling mechanisms in epithelial cells during development, from embryonic to adult epithelia. We largely focus on Drosophila, as quantitative analyses in this organism have provided a detailed characterization of the molecular mechanisms governing cell topologies, and discuss the conservation of these mechanisms across metazoans. We consider how changes at the molecular level translate to tissue-scale irreversible deformations, exploring the composition and assembly of cellular interfaces to unveil how junctions are remodeled to preserve tissue homeostasis during cell division, intercalation, invagination, ingression and extrusion.
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Affiliation(s)
- Marta Mira-Osuna
- Institut de Génétique et Développement de Rennes (IGDR), Université de Rennes, CNRS UMR 6290, F-35000 Rennes, France
| | - Roland Le Borgne
- Institut de Génétique et Développement de Rennes (IGDR), Université de Rennes, CNRS UMR 6290, F-35000 Rennes, France
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5
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Dornan AJ, Halberg KV, Beuter LK, Davies SA, Dow JAT. Compromised junctional integrity phenocopies age-dependent renal dysfunction in Drosophila Snakeskin mutants. J Cell Sci 2023; 136:jcs261118. [PMID: 37694602 PMCID: PMC10565245 DOI: 10.1242/jcs.261118] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 09/05/2023] [Indexed: 09/12/2023] Open
Abstract
Transporting epithelia provide a protective barrier against pathogenic insults while allowing the controlled exchange of ions, solutes and water with the external environment. In invertebrates, these functions depend on formation and maintenance of 'tight' septate junctions (SJs). However, the mechanism by which SJs affect transport competence and tissue homeostasis, and how these are modulated by ageing, remain incompletely understood. Here, we demonstrate that the Drosophila renal (Malpighian) tubules undergo an age-dependent decline in secretory capacity, which correlates with mislocalisation of SJ proteins and progressive degeneration in cellular morphology and tissue homeostasis. Acute loss of the SJ protein Snakeskin in adult tubules induced progressive changes in cellular and tissue architecture, including altered expression and localisation of junctional proteins with concomitant loss of cell polarity and barrier integrity, demonstrating that compromised junctional integrity is sufficient to replicate these ageing-related phenotypes. Taken together, our work demonstrates a crucial link between epithelial barrier integrity, tubule transport competence, renal homeostasis and organismal viability, as well as providing novel insights into the mechanisms underpinning ageing and renal disease.
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Affiliation(s)
- Anthony J. Dornan
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Kenneth V. Halberg
- Section for Cell and Neurobiology, Department of Biology, University of Copenhagen, Universitetsparken 15, Copenhagen DK-2100, Denmark
| | - Liesa-Kristin Beuter
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
- Department of Animal Ecology and Systematics, Justus-Liebig-University Giessen, Giessen D-35392, Germany
| | - Shireen-Anne Davies
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Julian A. T. Dow
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
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6
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Bruelle C, Pinot M, Daniel E, Daudé M, Mathieu J, Le Borgne R. Cell-intrinsic and -extrinsic roles of the ESCRT-III subunit Shrub in abscission of Drosophila sensory organ precursors. Development 2023; 150:dev201409. [PMID: 37226981 DOI: 10.1242/dev.201409] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Accepted: 04/17/2023] [Indexed: 05/17/2023]
Abstract
Although the molecular mechanisms governing abscission of isolated cells have largely been elucidated, those underlying the abscission of epithelial progenitors surrounded by epidermal cells (ECs), connected via cellular junctions, remain largely unexplored. Here, we investigated the remodeling of the paracellular diffusion barrier ensured by septate junctions (SJs) during cytokinesis of Drosophila sensory organ precursors (SOPs). We found that SOP cytokinesis involves the coordinated, polarized assembly and remodeling of SJs in the dividing cell and its neighbors, which remain connected to the former via membrane protrusions pointing towards the SOP midbody. SJ assembly and midbody basal displacement occur faster in SOPs than in ECs, leading to quicker disentanglement of neighboring cell membrane protrusions prior to midbody release. As reported in isolated cells, the endosomal sorting complex required for the transport-III component Shrub/CHMP4B is recruited at the midbody and cell-autonomously regulates abscission. In addition, Shrub is recruited to membrane protrusions and is required for SJ integrity, and alteration of SJ integrity leads to premature abscission. Our study uncovers cell-intrinsic and -extrinsic functions of Shrub in coordinating remodeling of the SJs and SOP abscission.
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Affiliation(s)
- Céline Bruelle
- Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR), UMR 6290, F-35000 Rennes, France
| | - Mathieu Pinot
- Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR), UMR 6290, F-35000 Rennes, France
| | - Emeline Daniel
- Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR), UMR 6290, F-35000 Rennes, France
| | - Marion Daudé
- Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR), UMR 6290, F-35000 Rennes, France
| | - Juliette Mathieu
- Center for Interdisciplinary Research in Biology (CIRB), UMR CNRS 7241/INSERM U1050, Collège de France, 11 place Marcelin Berthelot, 75005 Paris, France
| | - Roland Le Borgne
- Université de Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR), UMR 6290, F-35000 Rennes, France
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7
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Wang JM, Li ZF, Qi HY, Zhao Z, Yang WX. es-Arp3 and es-Eps8 regulate spermatogenesis via microfilaments in the seminiferous tubule of Eriocheir sinensis. Tissue Cell 2023; 81:102028. [PMID: 36709695 DOI: 10.1016/j.tice.2023.102028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/13/2022] [Accepted: 01/16/2023] [Indexed: 01/19/2023]
Abstract
Spermatogenesis is a complicated process that includes spermatogonia differentiation, spermatocytes meiosis, spermatids spermiogenesis and final release of spermatozoa. Actin-related protein 3 (Arp3) and epidermal growth factor receptor pathway substrate 8 (Eps8) are two actin binding proteins that regulate cell adhesion in seminiferous tubules during mammalian spermatogenesis. However, the functions of these two proteins during spermatogenesis in nonmammalian species, especially Crustacea, are still unknown. Here, we cloned es-Arp3 and es-Eps8 from the testis of Chinese mitten crab Eriocheir sinensis. es-Arp3 and es-Eps8 were located in spermatocytes, spermatids and spermatozoa. Knockdown of es-Arp3 and es-Eps8 in vivo caused morphological changes to seminiferous tubules including delayed spermatozoa release, shedding of germ cells and vacuoles. Filamentous-actin (F-actin) filaments network was disorganized due to deficiency of es-Arp3 and es-Eps8. Accompanying this, four junctional proteins (α-catenin, β-catenin, pinin and ZO1) displayed abnormal expression levels as well as penetrating biotin signals in seminiferous tubules. We also used the Arp2/3 complex inhibitor CK666 to block es-Arp3 activity and supported es-Arp3 knockdown results. In summary, our study demonstrated for the first time that es-Arp3 and es-Eps8 are important for spermatogenesis via regulating microfilament-mediated cell adhesion in Eriocheir sinensis.
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Affiliation(s)
- Jia-Ming Wang
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Zhen-Fang Li
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Hong-Yu Qi
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Zhan Zhao
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
| | - Wan-Xi Yang
- The Sperm Laboratory, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
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8
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Herbertz M, Lohr J, Lohr C, Dobler S. Knockdown of Na,K-ATPase β-subunits in Oncopeltus fasciatus induces molting problems and alterations in tracheal morphology. INSECT SCIENCE 2023; 30:375-397. [PMID: 36102008 DOI: 10.1111/1744-7917.13117] [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: 04/19/2022] [Revised: 08/17/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
The ubiquitously expressed transmembrane enzyme Na,K-ATPase (NKA) is vital in maintaining functionality of cells. The association of α- and β-subunits is believed to be essential for forming a functional enzyme. In the large milkweed bug Oncopeltus fasciatus four α1-paralogs and four β-subunits exist that can associate into NKA complexes. This diversity raises the question of possible tissue-specific distribution and function. While the α1-subunits are known to modulate cardenolide-resistance and ion-transport efficiency, the functional importance of the β-subunits needed further investigation. We here characterize all four different β-subunits at the cellular, tissue, and whole organismal scales. A knockdown of different β-subunits heavily interferes with molting success resulting in strongly hampered phenotypes. The failure of ecdysis might be related to disrupted septate junction (SJ) formation, also reflected in β2-suppression-induced alteration in tracheal morphology. Our data further suggest the existence of isolated β-subunits forming homomeric or β-heteromeric complexes. This possible standalone and structure-specific distribution of the β-subunits predicts further, yet unknown pump-independent functions. The different effects caused by β knockdowns highlight the importance of the various β-subunits to fulfill tissue-specific requirements.
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Affiliation(s)
- Marlena Herbertz
- Division of Molecular Evolutionary Biology, Department of Biology, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Hamburg, 20146, Germany
| | - Jennifer Lohr
- Division of Molecular Evolutionary Biology, Department of Biology, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Hamburg, 20146, Germany
| | - Christian Lohr
- Division of Neurophysiology, Department of Biology, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Hamburg, 20146, Germany
| | - Susanne Dobler
- Division of Molecular Evolutionary Biology, Department of Biology, Institute of Cell and Systems Biology of Animals, Universität Hamburg, Hamburg, 20146, Germany
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9
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Apical-basal polarity and the control of epithelial form and function. Nat Rev Mol Cell Biol 2022; 23:559-577. [PMID: 35440694 DOI: 10.1038/s41580-022-00465-y] [Citation(s) in RCA: 89] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2022] [Indexed: 02/02/2023]
Abstract
Epithelial cells are the most common cell type in all animals, forming the sheets and tubes that compose most organs and tissues. Apical-basal polarity is essential for epithelial cell form and function, as it determines the localization of the adhesion molecules that hold the cells together laterally and the occluding junctions that act as barriers to paracellular diffusion. Polarity must also target the secretion of specific cargoes to the apical, lateral or basal membranes and organize the cytoskeleton and internal architecture of the cell. Apical-basal polarity in many cells is established by conserved polarity factors that define the apical (Crumbs, Stardust/PALS1, aPKC, PAR-6 and CDC42), junctional (PAR-3) and lateral (Scribble, DLG, LGL, Yurt and RhoGAP19D) domains, although recent evidence indicates that not all epithelia polarize by the same mechanism. Research has begun to reveal the dynamic interactions between polarity factors and how they contribute to polarity establishment and maintenance. Elucidating these mechanisms is essential to better understand the roles of apical-basal polarity in morphogenesis and how defects in polarity contribute to diseases such as cancer.
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10
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Endocytosis at the Crossroad of Polarity and Signaling Regulation: Learning from Drosophila melanogaster and Beyond. Int J Mol Sci 2022; 23:ijms23094684. [PMID: 35563080 PMCID: PMC9101507 DOI: 10.3390/ijms23094684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/19/2022] [Accepted: 04/21/2022] [Indexed: 02/06/2023] Open
Abstract
Cellular trafficking through the endosomal–lysosomal system is essential for the transport of cargo proteins, receptors and lipids from the plasma membrane inside the cells and across membranous organelles. By acting as sorting stations, vesicle compartments direct the fate of their content for degradation, recycling to the membrane or transport to the trans-Golgi network. To effectively communicate with their neighbors, cells need to regulate their compartmentation and guide their signaling machineries to cortical membranes underlying these contact sites. Endosomal trafficking is indispensable for the polarized distribution of fate determinants, adaptors and junctional proteins. Conversely, endocytic machineries cooperate with polarity and scaffolding components to internalize receptors and target them to discrete membrane domains. Depending on the cell and tissue context, receptor endocytosis can terminate signaling responses but can also activate them within endosomes that act as signaling platforms. Therefore, cell homeostasis and responses to environmental cues rely on the dynamic cooperation of endosomal–lysosomal machineries with polarity and signaling cues. This review aims to address advances and emerging concepts on the cooperative regulation of endocytosis, polarity and signaling, primarily in Drosophila melanogaster and discuss some of the open questions across the different cell and tissue types that have not yet been fully explored.
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11
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Pogodalla N, Winkler B, Klämbt C. Glial Tiling in the Insect Nervous System. Front Cell Neurosci 2022; 16:825695. [PMID: 35250488 PMCID: PMC8891220 DOI: 10.3389/fncel.2022.825695] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/06/2022] [Indexed: 11/30/2022] Open
Abstract
The Drosophila nervous system comprises a small number of well characterized glial cell classes. The outer surface of the central nervous system (CNS) is protected by a glial derived blood-brain barrier generated by perineurial and subperineurial glia. All neural stem cells and all neurons are engulfed by cortex glial cells. The inner neuropil region, that harbors all synapses and dendrites, is covered by ensheathing glia and infiltrated by astrocyte-like glial cells. All these glial cells show a tiled organization with an often remarkable plasticity where glial cells of one cell type invade the territory of the neighboring glial cell type upon its ablation. Here, we summarize the different glial tiling patterns and based on the different modes of cell-cell contacts we hypothesize that different molecular mechanisms underlie tiling of the different glial cell types.
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12
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Sharp KA, Khoury MJ, Wirtz-Peitz F, Bilder D. Evidence for a nuclear role for Drosophila Dlg as a regulator of the NURF complex. Mol Biol Cell 2021; 32:ar23. [PMID: 34495684 PMCID: PMC8693970 DOI: 10.1091/mbc.e21-04-0187] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Scribble (Scrib), Discs-large (Dlg), and Lethal giant larvae (Lgl) are basolateral regulators of epithelial polarity and tumor suppressors whose molecular mechanisms of action remain unclear. We used proximity biotinylation to identify proteins localized near Dlg in the Drosophila wing imaginal disc epithelium. In addition to expected membrane- and cytoskeleton-associated protein classes, nuclear proteins were prevalent in the resulting mass spectrometry dataset, including all four members of the nucleosome remodeling factor (NURF) chromatin remodeling complex. Subcellular fractionation demonstrated a nuclear pool of Dlg and proximity ligation confirmed its position near the NURF complex. Genetic analysis showed that NURF activity is also required for the overgrowth of dlg tumors, and this growth suppression correlated with a reduction in Hippo pathway gene expression. Together, these data suggest a nuclear role for Dlg in regulating chromatin and transcription through a more direct mechanism than previously thought.
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Affiliation(s)
- Katherine A Sharp
- Department of Molecular and Cell Biology, University of California-Berkeley, Berkeley CA 94720
| | - Mark J Khoury
- Department of Molecular and Cell Biology, University of California-Berkeley, Berkeley CA 94720
| | | | - David Bilder
- Department of Molecular and Cell Biology, University of California-Berkeley, Berkeley CA 94720
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13
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Li X, Fetter R, Schwabe T, Jung C, Liu L, Steller H, Gaul U. The cAMP effector PKA mediates Moody GPCR signaling in Drosophila blood-brain barrier formation and maturation. eLife 2021; 10:68275. [PMID: 34382936 PMCID: PMC8390003 DOI: 10.7554/elife.68275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 08/11/2021] [Indexed: 01/01/2023] Open
Abstract
The blood-brain barrier (BBB) of Drosophila comprises a thin epithelial layer of subperineural glia (SPG), which ensheath the nerve cord and insulate it against the potassium-rich hemolymph by forming intercellular septate junctions (SJs). Previously, we identified a novel Gi/Go protein-coupled receptor (GPCR), Moody, as a key factor in BBB formation at the embryonic stage. However, the molecular and cellular mechanisms of Moody signaling in BBB formation and maturation remain unclear. Here, we identify cAMP-dependent protein kinase A (PKA) as a crucial antagonistic Moody effector that is required for the formation, as well as for the continued SPG growth and BBB maintenance in the larva and adult stage. We show that PKA is enriched at the basal side of the SPG cell and that this polarized activity of the Moody/PKA pathway finely tunes the enormous cell growth and BBB integrity. Moody/PKA signaling precisely regulates the actomyosin contractility, vesicle trafficking, and the proper SJ organization in a highly coordinated spatiotemporal manner. These effects are mediated in part by PKA's molecular targets MLCK and Rho1. Moreover, 3D reconstruction of SJ ultrastructure demonstrates that the continuity of individual SJ segments, and not their total length, is crucial for generating a proper paracellular seal. Based on these findings, we propose that polarized Moody/PKA signaling plays a central role in controlling the cell growth and maintaining BBB integrity during the continuous morphogenesis of the SPG secondary epithelium, which is critical to maintain tissue size and brain homeostasis during organogenesis.
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Affiliation(s)
- Xiaoling Li
- Tianjin Cancer Hospital Airport Hospital, Tianjin Medical University Cancer Institute & Hospital, Tianjin, China.,Department of Biochemistry, Gene Center, Center of Integrated Protein Science (CIPSM), University of Munich, Munich, Germany.,Rockefeller University, New York, United States
| | - Richard Fetter
- Janelia Farm Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Tina Schwabe
- Department of Biochemistry, Gene Center, Center of Integrated Protein Science (CIPSM), University of Munich, Munich, Germany
| | - Christophe Jung
- Department of Biochemistry, Gene Center, Center of Integrated Protein Science (CIPSM), University of Munich, Munich, Germany
| | - Liren Liu
- Department of Gastrointestinal Cancer Biology, Tianjin Medical University Cancer Institute & Hospital; National Clinical Research Center for Cancer; Key Laboratory of Cancer Prevention and Therapy; Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | | | - Ulrike Gaul
- Department of Biochemistry, Gene Center, Center of Integrated Protein Science (CIPSM), University of Munich, Munich, Germany.,Rockefeller University, New York, United States
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14
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Alhadyian H, Shoaib D, Ward RE. Septate junction proteins are required for egg elongation and border cell migration during oogenesis in Drosophila. G3-GENES GENOMES GENETICS 2021; 11:6237887. [PMID: 33871584 PMCID: PMC8495938 DOI: 10.1093/g3journal/jkab127] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/09/2021] [Indexed: 11/16/2022]
Abstract
Protein components of the invertebrate occluding junction—known as the septate junction (SJ)—are required for morphogenetic developmental events during embryogenesis in Drosophila melanogaster. In order to determine whether SJ proteins are similarly required for morphogenesis during other developmental stages, we investigated the localization and requirement of four representative SJ proteins during oogenesis: Contactin, Macroglobulin complement-related, Neurexin IV, and Coracle. A number of morphogenetic processes occur during oogenesis, including egg elongation, formation of dorsal appendages, and border cell (BC) migration. We found that all four SJ proteins are expressed in egg chambers throughout oogenesis, with the highest and the most sustained levels in the follicular epithelium (FE). In the FE, SJ proteins localize along the lateral membrane during early and mid-oogenesis, but become enriched in an apical-lateral domain (the presumptive SJ) by stage 11. SJ protein relocalization requires the expression of other SJ proteins, as well as Rab5 and Rab11 like SJ biogenesis in the embryo. Knocking down the expression of these SJ proteins in follicle cells throughout oogenesis results in egg elongation defects and abnormal dorsal appendages. Similarly, reducing the expression of SJ genes in the BC cluster results in BC migration defects. Together, these results demonstrate an essential requirement for SJ genes in morphogenesis during oogenesis, and suggest that SJ proteins may have conserved functions in epithelial morphogenesis across developmental stages.
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Affiliation(s)
- Haifa Alhadyian
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045, USA
| | - Dania Shoaib
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045, USA
| | - Robert E Ward
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045, USA
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15
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Böhme MA, McCarthy AW, Blaum N, Berezeckaja M, Ponimaskine K, Schwefel D, Walter AM. Glial Synaptobrevin mediates peripheral nerve insulation, neural metabolic supply, and is required for motor function. Glia 2021; 69:1897-1915. [PMID: 33811396 DOI: 10.1002/glia.24000] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 03/12/2021] [Accepted: 03/17/2021] [Indexed: 01/10/2023]
Abstract
Peripheral nerves contain sensory and motor neuron axons coated by glial cells whose interplay ensures function, but molecular details are lacking. SNARE-proteins mediate the exchange and secretion of cargo by fusing vesicles with target organelles, but how glial SNAREs contribute to peripheral nerve function is largely unknown. We, here, identify non-neuronal Synaptobrevin (Syb) as the essential vesicular SNARE in Drosophila peripheral glia to insulate and metabolically supply neurons. We show that tetanus neurotoxin light chain (TeNT-LC), which potently inhibits SNARE-mediated exocytosis from neurons, also impairs peripheral nerve function when selectively expressed in glia, causing nerve disintegration, defective axonal transport, tetanic muscle hyperactivity, impaired locomotion, and lethality. While TeNT-LC disrupts neural function by cleaving neuronal Synaptobrevin (nSyb), it targets non-neuronal Synaptobrevin (Syb) in glia, which it cleaves at low rates: Glial knockdown of Syb (but not nSyb) phenocopied glial TeNT-LC expression whose effects were reverted by a TeNT-LC-insensitive Syb mutant. We link Syb-necessity to two distinct glial subtypes: Impairing Syb function in subperineurial glia disrupted nerve morphology, axonal transport, and locomotion, likely, because nerve-isolating septate junctions (SJs) could not form as essential SJ components (like the cell adhesion protein Neurexin-IV) were mistargeted. Interference with Syb in axon-encircling wrapping glia left nerve morphology and locomotion intact but impaired axonal transport, likely because neural metabolic supply was disrupted due to the mistargeting of metabolite shuffling monocarboxylate transporters. Our study identifies crucial roles of Syb in various glial subtypes to ensure glial-glial and glial-neural interplay needed for proper nerve function, animal motility, and survival.
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Affiliation(s)
- Mathias A Böhme
- Molecular and Theoretical Neuroscience, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), FMP im CharitéCrossOver, Berlin, Germany.,Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anthony W McCarthy
- Molecular and Theoretical Neuroscience, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), FMP im CharitéCrossOver, Berlin, Germany
| | - Natalie Blaum
- Molecular and Theoretical Neuroscience, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), FMP im CharitéCrossOver, Berlin, Germany
| | - Monika Berezeckaja
- Molecular and Theoretical Neuroscience, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), FMP im CharitéCrossOver, Berlin, Germany
| | - Kristina Ponimaskine
- Molecular and Theoretical Neuroscience, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), FMP im CharitéCrossOver, Berlin, Germany
| | - David Schwefel
- Institute of Medical Physics and Biophysics, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Alexander M Walter
- Molecular and Theoretical Neuroscience, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), FMP im CharitéCrossOver, Berlin, Germany.,Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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16
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Rice C, De O, Alhadyian H, Hall S, Ward RE. Expanding the Junction: New Insights into Non-Occluding Roles for Septate Junction Proteins during Development. J Dev Biol 2021; 9:11. [PMID: 33801162 PMCID: PMC8006247 DOI: 10.3390/jdb9010011] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/15/2021] [Accepted: 03/17/2021] [Indexed: 12/17/2022] Open
Abstract
The septate junction (SJ) provides an occluding function for epithelial tissues in invertebrate organisms. This ability to seal the paracellular route between cells allows internal tissues to create unique compartments for organ function and endows the epidermis with a barrier function to restrict the passage of pathogens. Over the past twenty-five years, numerous investigators have identified more than 30 proteins that are required for the formation or maintenance of the SJs in Drosophila melanogaster, and have determined many of the steps involved in the biogenesis of the junction. Along the way, it has become clear that SJ proteins are also required for a number of developmental events that occur throughout the life of the organism. Many of these developmental events occur prior to the formation of the occluding junction, suggesting that SJ proteins possess non-occluding functions. In this review, we will describe the composition of SJs, taking note of which proteins are core components of the junction versus resident or accessory proteins, and the steps involved in the biogenesis of the junction. We will then elaborate on the functions that core SJ proteins likely play outside of their role in forming the occluding junction and describe studies that provide some cell biological perspectives that are beginning to provide mechanistic understanding of how these proteins function in developmental contexts.
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Affiliation(s)
- Clinton Rice
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA; (C.R.); (H.A.)
| | - Oindrila De
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA;
| | - Haifa Alhadyian
- Department of Molecular Biosciences, University of Kansas, Lawrence, KS 66045, USA; (C.R.); (H.A.)
| | | | - Robert E. Ward
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA;
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17
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DaCrema D, Bhandari R, Karanja F, Yano R, Halme A. Ecdysone regulates the Drosophila imaginal disc epithelial barrier, determining the length of regeneration checkpoint delay. Development 2021; 148:dev.195057. [PMID: 33658221 DOI: 10.1242/dev.195057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 02/15/2021] [Indexed: 02/06/2023]
Abstract
Regeneration of Drosophila imaginal discs, larval precursors to adult tissues, activates a regeneration checkpoint that coordinates regenerative growth with developmental progression. This regeneration checkpoint results from the release of the relaxin-family peptide Dilp8 from regenerating imaginal tissues. Secreted Dilp8 protein is detected within the imaginal disc lumen, in which it is separated from its receptor target Lgr3, which is expressed in the brain and prothoracic gland, by the disc epithelial barrier. Here, we demonstrate that following damage the imaginal disc epithelial barrier limits Dilp8 signaling and the duration of regeneration checkpoint delay. We also find that the barrier becomes increasingly impermeable to the transepithelial diffusion of labeled dextran during the second half of the third instar. This change in barrier permeability is driven by the steroid hormone ecdysone and correlates with changes in localization of Coracle, a component of the septate junctions that is required for the late-larval impermeable epithelial barrier. Based on these observations, we propose that the imaginal disc epithelial barrier regulates the duration of the regenerative checkpoint, providing a mechanism by which tissue function can signal the completion of regeneration.
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Affiliation(s)
- Danielle DaCrema
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22902, USA
| | - Rajan Bhandari
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22902, USA
| | - Faith Karanja
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22902, USA
| | - Ryunosuke Yano
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22902, USA
| | - Adrian Halme
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22902, USA
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18
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Rouka E, Gourgoulianni N, Lüpold S, Hatzoglou C, Gourgoulianis K, Blanckenhorn WU, Zarogiannis SG. The Drosophila septate junctions beyond barrier function: Review of the literature, prediction of human orthologs of the SJ-related proteins and identification of protein domain families. Acta Physiol (Oxf) 2021; 231:e13527. [PMID: 32603029 DOI: 10.1111/apha.13527] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 06/20/2020] [Accepted: 06/22/2020] [Indexed: 12/20/2022]
Abstract
The involvement of Septate Junctions (SJs) in critical cellular functions that extend beyond their role as diffusion barriers in the epithelia and the nervous system has made the fruit fly an ideal model for the study of human diseases associated with impaired Tight Junction (TJ) function. In this study, we summarized current knowledge of the Drosophila melanogaster SJ-related proteins, focusing on their unconventional functions. Additionally, we sought to identify human orthologs of the corresponding genes as well as protein domain families. The systematic literature search was performed in PubMed and Scopus databases using relevant key terms. Orthologs were predicted using the DIOPT tool and aligned protein regions were determined from the Pfam database. 3-D models of the smooth SJ proteins were built on the Phyre2 and DMPFold protein structure prediction servers. A total of 30 proteins were identified as relatives to the SJ cellular structure. Key roles of these proteins, mainly in the regulation of morphogenetic events and cellular signalling, were highlighted. The investigation of protein domain families revealed that the SJ-related proteins contain conserved domains that are required not only for cell-cell interactions and cell polarity but also for cellular signalling and immunity. DIOPT analysis of orthologs identified novel human genes as putative functional homologs of the fruit fly SJ genes. A gap in our knowledge was identified regarding the domains that occur in the proteins encoded by eight SJ-associated genes. Future investigation of these domains is needed to provide functional information.
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Affiliation(s)
- Erasmia Rouka
- Department of Physiology Faculty of Medicine School of Health Sciences University of ThessalyBIOPOLIS Larissa Greece
| | - Natalia Gourgoulianni
- Department of Evolutionary Biology and Environmental Studies University of Zurich Zurich Switzerland
| | - Stefan Lüpold
- Department of Evolutionary Biology and Environmental Studies University of Zurich Zurich Switzerland
| | - Chrissi Hatzoglou
- Department of Physiology Faculty of Medicine School of Health Sciences University of ThessalyBIOPOLIS Larissa Greece
- Department of Respiratory Medicine Faculty of Medicine School of Health Sciences University of ThessalyBIOPOLIS Larissa Greece
| | - Konstantinos Gourgoulianis
- Department of Respiratory Medicine Faculty of Medicine School of Health Sciences University of ThessalyBIOPOLIS Larissa Greece
| | - Wolf U. Blanckenhorn
- Department of Evolutionary Biology and Environmental Studies University of Zurich Zurich Switzerland
| | - Sotirios G. Zarogiannis
- Department of Physiology Faculty of Medicine School of Health Sciences University of ThessalyBIOPOLIS Larissa Greece
- Department of Respiratory Medicine Faculty of Medicine School of Health Sciences University of ThessalyBIOPOLIS Larissa Greece
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19
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Pannen H, Rapp T, Klein T. The ESCRT machinery regulates retromer-dependent transcytosis of septate junction components in Drosophila. eLife 2020; 9:61866. [PMID: 33377869 PMCID: PMC7848756 DOI: 10.7554/elife.61866] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 12/29/2020] [Indexed: 12/30/2022] Open
Abstract
Loss of ESCRT function in Drosophila imaginal discs is known to cause neoplastic overgrowth fueled by mis-regulation of signaling pathways. Its impact on junctional integrity, however, remains obscure. To dissect the events leading to neoplasia, we used transmission electron microscopy (TEM) on wing imaginal discs temporally depleted of the ESCRT-III core component Shrub. We find a specific requirement for Shrub in maintaining septate junction (SJ) integrity by transporting the claudin Megatrachea (Mega) to the SJ. In absence of Shrub function, Mega is lost from the SJ and becomes trapped on endosomes coated with the endosomal retrieval machinery retromer. We show that ESCRT function is required for apical localization and mobility of retromer positive carrier vesicles, which mediate the biosynthetic delivery of Mega to the SJ. Accordingly, loss of retromer function impairs the anterograde transport of several SJ core components, revealing a novel physiological role for this ancient endosomal agent. Proteins are large molecules responsible for a variety of activities that cells needs to perform to survive; from respiration to copying DNA before cells divide. To perform these roles proteins need to be transported to the correct cell compartment, or to the cell membrane. This protein trafficking depends on the endosomal system, a set of membrane compartments that can travel within the cell and act as a protein sorting hub. This system needs its own proteins to work properly. In particular, there are two sets of proteins that are crucial for the endosomal systems activity: a group of proteins known as the ESCRT (endosomal sorting complex required for transport) machinery and a complex called retromer. The retromer complex regulates recycling of receptor proteins so they can be reused, while the ESCRT machinery mediates degradation of proteins that the cell does not require anymore. In the epithelia of fruit fly larvae – the tissues that form layers of cells, usually covering an organ but also making structures like wings – defects in ESCRT activity lead to a loss of tissue integrity. This loss of tissue integrity suggests that the endosomal system might be involved in transporting proteins that form cellular junctions, the multiprotein complexes that establish contacts between cells or between a cell and the extracellular space. In arthropods such as the fruit fly, the adherens junction and the septate junction are two types of cellular junctions important for the integrity of epithelia integrity. Adherens junctions allow cells to adhere to each other, while septate junctions stop nutrient molecules, ions and water from leaking into the tissue. The role of the endosomal system in trafficking the proteins that form septate junctions remains a mystery. To better understand the role of the endosomal system in regulating cell junctions and tissue integrity, Pannen et al. blocked the activity of either the ESCRT or retromer in wing imaginal discs – the future wings – of fruit fly larvae. Pannen et al. then analyzed the effects of these endosomal defects on cellular junctions using an imaging technique called transmission electron microscopy. The results showed that both ESCRT and retromer activities are necessary for the correct delivery of septate junction components to the cell membrane. However, neither retromer nor ESCRT were required for the delivery of adherens junction proteins. These findings shed light on how retromer and the ESCRT machinery are involved in the epithelial tissue integrity of fruit fly larvae through their effects on cell junctions. Humans have their own versions of the ESCRT, retromer, and cell junction proteins, all of which are very similar to their fly counterparts. Since defects in the human versions of these proteins have been associated with a variety of diseases, from infections to cancer, these results may have implications for research into treating those diseases.
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Affiliation(s)
- Hendrik Pannen
- Institute of Genetics, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Tim Rapp
- Institute of Genetics, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Thomas Klein
- Institute of Genetics, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
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20
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The Transmembrane Proteins M6 and Anakonda Cooperate to Initiate Tricellular Junction Assembly in Epithelia of Drosophila. Curr Biol 2020; 30:4254-4262.e5. [DOI: 10.1016/j.cub.2020.08.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/30/2020] [Accepted: 08/03/2020] [Indexed: 11/18/2022]
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21
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Cammarota C, Finegan TM, Wilson TJ, Yang S, Bergstralh DT. An Axon-Pathfinding Mechanism Preserves Epithelial Tissue Integrity. Curr Biol 2020; 30:5049-5057.e3. [PMID: 33065006 DOI: 10.1016/j.cub.2020.09.061] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 08/21/2020] [Accepted: 09/18/2020] [Indexed: 01/09/2023]
Abstract
Epithelial tissues form the boundaries of organs, where they perform a range of functions, including secretion, absorption, and protection. These tissues are commonly composed of discrete cell layers-sheets of cells that are one-cell thick. In multiple systems examined, epithelial cells round up and move in the apical direction before dividing, likely in response to neighbor-cell crowding [1-6]. Because of this movement, daughter cells may be born displaced from the tissue layer. Reintegration of these displaced cells supports tissue growth and maintains tissue architecture [4]. Two conserved IgCAMs (immunoglobulin superfamily cell adhesion molecules), neuroglian (Nrg) and fasciclin 2 (Fas2), participate in cell reintegration in the Drosophila follicular epithelium [4]. Like their vertebrate orthologs L1CAM and NCAM1/2, respectively, Nrg and Fas2 are cell adhesion molecules primarily studied in the context of nervous system development [7-10]. Consistent with this, we identify another neural IgCAM, Fasciclin 3 (Fas3), as a reintegration factor. Nrg, Fas2, and Fas3 are components of the insect septate junction, the functional equivalent of the vertebrate tight junction, but proliferating follicle cells do not have mature septate junctions, and we find that the septate junction protein neurexin IV does not participate in reintegration [11, 12]. Here, we show that epithelial reintegration works in the same way as IgCAM-mediated axon growth and pathfinding; it relies not only on extracellular adhesion but also mechanical coupling between IgCAMs and the lateral spectrin-based membrane skeleton. Our work indicates that reintegration is mediated by a distinct epithelial adhesion assembly that is compositionally and functionally equivalent to junctions made between axons.
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Affiliation(s)
- Christian Cammarota
- Department of Physics & Astronomy, University of Rochester, Rochester, NY 14627, USA
| | - Tara M Finegan
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Tyler J Wilson
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Sifan Yang
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Dan T Bergstralh
- Department of Physics & Astronomy, University of Rochester, Rochester, NY 14627, USA; Department of Biology, University of Rochester, Rochester, NY 14627, USA; Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY 14627, USA.
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22
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Finegan TM, Bergstralh DT. Neuronal immunoglobulin superfamily cell adhesion molecules in epithelial morphogenesis: insights from Drosophila. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190553. [PMID: 32829687 PMCID: PMC7482216 DOI: 10.1098/rstb.2019.0553] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2020] [Indexed: 12/25/2022] Open
Abstract
In this review, we address the function of immunoglobulin superfamily cell adhesion molecules (IgCAMs) in epithelia. Work in the Drosophila model system in particular has revealed novel roles for calcium-independent adhesion molecules in the morphogenesis of epithelial tissues. We review the molecular composition of lateral junctions with a focus on their IgCAM components and reconsider the functional roles of epithelial lateral junctions. The epithelial IgCAMs discussed in this review have well-defined roles in the nervous system, particularly in the process of axon guidance, suggesting functional overlap and conservation in mechanism between that process and epithelial remodelling. We expand on the hypothesis that epithelial occluding junctions and synaptic junctions are compositionally equivalent and present a novel hypothesis that the mechanism of epithelial cell (re)integration and synaptic junction formation are shared. We highlight the importance of considering non-cadherin-based adhesion in our understanding of the mechanics of epithelial tissues and raise questions to direct future work. This article is part of the discussion meeting issue 'Contemporary morphogenesis'.
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23
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Lim HY, Bao H, Liu Y, Wang W. Select Septate Junction Proteins Direct ROS-Mediated Paracrine Regulation of Drosophila Cardiac Function. Cell Rep 2020; 28:1455-1470.e4. [PMID: 31390561 DOI: 10.1016/j.celrep.2019.07.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 04/18/2019] [Accepted: 06/27/2019] [Indexed: 12/27/2022] Open
Abstract
Septate junction (SJ) complex proteins act in unison to provide a paracellular barrier and maintain structural integrity. Here, we identify a non-barrier role of two individual SJ proteins, Coracle (Cora) and Kune-kune (Kune). Reactive oxygen species (ROS)-p38 MAPK signaling in non-myocytic pericardial cells (PCs) is important for maintaining normal cardiac physiology in Drosophila. However, the underlying mechanisms remain unknown. We find that in PCs, Cora and Kune are altered in abundance in response to manipulations of ROS-p38 signaling. Genetic analyses establish Cora and Kune as key effectors of ROS-p38 signaling in PCs on proper heart function. We further determine that Cora regulates normal Kune levels in PCs, which in turn modulates normal Kune levels in the cardiomyocytes essential for proper heart function. Our results thereby reveal select SJ proteins Cora and Kune as signaling mediators of the PC-derived ROS regulation of cardiac physiology.
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Affiliation(s)
- Hui-Ying Lim
- Department of Physiology, University of Oklahoma Health Science Center, Oklahoma City, OK, USA.
| | - Hong Bao
- Department of Physiology, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Ying Liu
- Department of Physiology, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Weidong Wang
- Department of Medicine, Section of Endocrinology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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24
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Ventura G, Moreira S, Barros-Carvalho A, Osswald M, Morais-de-Sá E. Lgl cortical dynamics are independent of binding to the Scrib-Dlg complex but require Dlg-dependent restriction of aPKC. Development 2020; 147:dev.186593. [PMID: 32665243 DOI: 10.1242/dev.186593] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 07/02/2020] [Indexed: 01/06/2023]
Abstract
Apical-basal polarity underpins the formation of epithelial barriers that are crucial for metazoan physiology. Although apical-basal polarity is long known to require the basolateral determinants Lethal Giant Larvae (Lgl), Discs Large (Dlg) and Scribble (Scrib), mechanistic understanding of their function is limited. Lgl plays a role as an aPKC inhibitor, but it remains unclear whether Lgl also forms complexes with Dlg or Scrib. Using fluorescence recovery after photobleaching, we show that Lgl does not form immobile complexes at the lateral domain of Drosophila follicle cells. Optogenetic depletion of plasma membrane PIP2 or dlg mutants accelerate Lgl cortical dynamics. However, Dlg and Scrib are required only for Lgl localization and dynamic behavior in the presence of aPKC function. Furthermore, light-induced oligomerization of basolateral proteins indicates that Lgl is not part of the Scrib-Dlg complex in the follicular epithelium. Thus, Scrib and Dlg are necessary to repress aPKC activity in the lateral domain but do not provide cortical binding sites for Lgl. Our work therefore highlights that Lgl does not act in a complex but in parallel with Scrib-Dlg to antagonize apical determinants.
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Affiliation(s)
- Guilherme Ventura
- i3S (Instituto de Investigação e Inovação em Saúde, Universidade do Porto) and IBMC (Instituto de Biologia Molecular e Celular), Rua Alfredo Allen, 208, 4200-135 Porto, Portugal
| | - Sofia Moreira
- i3S (Instituto de Investigação e Inovação em Saúde, Universidade do Porto) and IBMC (Instituto de Biologia Molecular e Celular), Rua Alfredo Allen, 208, 4200-135 Porto, Portugal
| | - André Barros-Carvalho
- i3S (Instituto de Investigação e Inovação em Saúde, Universidade do Porto) and IBMC (Instituto de Biologia Molecular e Celular), Rua Alfredo Allen, 208, 4200-135 Porto, Portugal
| | - Mariana Osswald
- i3S (Instituto de Investigação e Inovação em Saúde, Universidade do Porto) and IBMC (Instituto de Biologia Molecular e Celular), Rua Alfredo Allen, 208, 4200-135 Porto, Portugal
| | - Eurico Morais-de-Sá
- i3S (Instituto de Investigação e Inovação em Saúde, Universidade do Porto) and IBMC (Instituto de Biologia Molecular e Celular), Rua Alfredo Allen, 208, 4200-135 Porto, Portugal
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25
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Salinas-Saavedra M, Martindale MQ. Par protein localization during the early development of Mnemiopsis leidyi suggests different modes of epithelial organization in the metazoa. eLife 2020; 9:54927. [PMID: 32716297 PMCID: PMC7441587 DOI: 10.7554/elife.54927] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 07/23/2020] [Indexed: 02/07/2023] Open
Abstract
In bilaterians and cnidarians, epithelial cell-polarity is regulated by the interactions between Par proteins, Wnt/PCP signaling pathway, and cell-cell adhesion. Par proteins are highly conserved across Metazoa, including ctenophores. But strikingly, ctenophore genomes lack components of the Wnt/PCP pathway and cell-cell adhesion complexes raising the question if ctenophore cells are polarized by mechanisms involving Par proteins. Here, by using immunohistochemistry and live-cell imaging of specific mRNAs, we describe for the first time the subcellular localization of selected Par proteins in blastomeres and epithelial cells during the embryogenesis of the ctenophore Mnemiopsis leidyi. We show that these proteins distribute differently compared to what has been described for other animals, even though they segregate in a host-specific fashion when expressed in cnidarian embryos. This differential localization might be related to the emergence of different junctional complexes during metazoan evolution.
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Affiliation(s)
- Miguel Salinas-Saavedra
- The Whitney Laboratory for Marine Bioscience, and the Department of Biology, University of Florida, St. Augustine, United States
| | - Mark Q Martindale
- The Whitney Laboratory for Marine Bioscience, and the Department of Biology, University of Florida, St. Augustine, United States
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26
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Khoury MJ, Bilder D. Distinct activities of Scrib module proteins organize epithelial polarity. Proc Natl Acad Sci U S A 2020; 117:11531-11540. [PMID: 32414916 PMCID: PMC7260944 DOI: 10.1073/pnas.1918462117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A polarized architecture is central to both epithelial structure and function. In many cells, polarity involves mutual antagonism between the Par complex and the Scribble (Scrib) module. While molecular mechanisms underlying Par-mediated apical determination are well-understood, how Scrib module proteins specify the basolateral domain remains unknown. Here, we demonstrate dependent and independent activities of Scrib, Discs-large (Dlg), and Lethal giant larvae (Lgl) using the Drosophila follicle epithelium. Our data support a linear hierarchy for localization, but rule out previously proposed protein-protein interactions as essential for polarization. Cortical recruitment of Scrib does not require palmitoylation or polar phospholipid binding but instead an independent cortically stabilizing activity of Dlg. Scrib and Dlg do not directly antagonize atypical protein kinase C (aPKC), but may instead restrict aPKC localization by enabling the aPKC-inhibiting activity of Lgl. Importantly, while Scrib, Dlg, and Lgl are each required, all three together are not sufficient to antagonize the Par complex. Our data demonstrate previously unappreciated diversity of function within the Scrib module and begin to define the elusive molecular functions of Scrib and Dlg.
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Affiliation(s)
- Mark J Khoury
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - David Bilder
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
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27
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Königsmann T, Parfentev I, Urlaub H, Riedel D, Schuh R. The bicistronic gene würmchen encodes two essential components for epithelial development in Drosophila. Dev Biol 2020; 463:53-62. [PMID: 32361005 DOI: 10.1016/j.ydbio.2020.04.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 03/17/2020] [Accepted: 04/07/2020] [Indexed: 11/24/2022]
Abstract
Epithelial tissues are fundamental for the establishment and maintenance of different body compartments in multicellular animals. To achieve this specific task epithelial sheets secrete an apical extracellular matrix for tissue strength and protection and they organize a transepithelial barrier function, which is mediated by tight junctions in vertebrates or septate junctions in invertebrates. Here, we show that the bicistronic gene würmchen is functionally expressed in epithelial tissues. CRISPR/Cas9-mediated mutations in both coding sequences reveal two essential polypeptides, Würmchen1 and Würmchen2, which are both necessary for normal epithelial tissue development. Würmchen1 represents a genuine septate junction core component. It is required during embryogenesis for septate junction organization, the establishment of a transepithelial barrier function, distinct cellular transport processes and tracheal system morphogenesis. Würmchen2 is localized in the apical membrane region of epithelial tissues and in a central core of the tracheal lumen during embryogenesis. It is essential during the later larval development.
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Affiliation(s)
- Tatiana Königsmann
- Research Group Molecular Organogenesis, Max-Planck-Institute for Biophysical Chemistry, Am Fassberg, D-37077, Göttingen, Germany
| | - Iwan Parfentev
- Research Group Bioanalytical Mass Spectrometry, Max-Planck-Institute for Biophysical Chemistry, Am Fassberg, D-37077, Göttingen, Germany
| | - Henning Urlaub
- Research Group Bioanalytical Mass Spectrometry, Max-Planck-Institute for Biophysical Chemistry, Am Fassberg, D-37077, Göttingen, Germany; Bioanalytics, Institute for Clinical Chemistry, University Medical Center, Robert-Koch-Strasse 420, 37075 Göttingen, Germany
| | - Dietmar Riedel
- Electron Microscopy Group, Max-Planck-Institute for Biophysical Chemistry, Am Fassberg, D-37077, Göttingen, Germany
| | - Reinhard Schuh
- Research Group Molecular Organogenesis, Max-Planck-Institute for Biophysical Chemistry, Am Fassberg, D-37077, Göttingen, Germany.
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Bonello TT, Choi W, Peifer M. Scribble and Discs-large direct initial assembly and positioning of adherens junctions during the establishment of apical-basal polarity. Development 2019; 146:dev.180976. [PMID: 31628110 DOI: 10.1242/dev.180976] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 10/14/2019] [Indexed: 01/05/2023]
Abstract
Apical-basal polarity is a fundamental property of animal tissues. Drosophila embryos provide an outstanding model for defining mechanisms that initiate and maintain polarity. Polarity is initiated during cellularization, when cell-cell adherens junctions are positioned at the future boundary of apical and basolateral domains. Polarity maintenance then involves complementary and antagonistic interplay between apical and basal polarity complexes. The Scribble/Dlg module is well-known for promoting basolateral identity during polarity maintenance. Here, we report a surprising role for Scribble/Dlg in polarity initiation, placing it near the top of the network-positioning adherens junctions. Scribble and Dlg are enriched in nascent adherens junctions, are essential for adherens junction positioning and supermolecular assembly, and also play a role in basal junction assembly. We test the hypotheses for the underlying mechanisms, exploring potential effects on protein trafficking, cytoskeletal polarity or Par-1 localization/function. Our data suggest that the Scribble/Dlg module plays multiple roles in polarity initiation. Different domains of Scribble contribute to these distinct roles. Together, these data reveal novel roles for Scribble/Dlg as master scaffolds regulating assembly of distinct junctional complexes at different times and places.
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Affiliation(s)
- Teresa T Bonello
- Department of Biology, University of North Carolina at Chapel Hill, CB#3280, Chapel Hill, NC 27599-3280, USA
| | - Wangsun Choi
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Mark Peifer
- Department of Biology, University of North Carolina at Chapel Hill, CB#3280, Chapel Hill, NC 27599-3280, USA .,Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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29
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Sharifkhodaei Z, Gilbert MM, Auld VJ. Scribble and Discs Large mediate tricellular junction formation. Development 2019; 146:dev.174763. [PMID: 31444218 DOI: 10.1242/dev.174763] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 08/15/2019] [Indexed: 01/22/2023]
Abstract
Junctional complexes that mediate cell adhesion are key to epithelial integrity, cell division and permeability barrier formation. In Drosophila, the scaffolding proteins Scribble (Scrib) and Discs Large (Dlg) are key regulators of epithelial polarity, proliferation, assembly of junctions and protein trafficking. We found that Scrib and Dlg are necessary for the formation of the tricellular junction (TCJ), a unique junction that forms in epithelia at the point of convergence of three neighboring cells. Scrib and Dlg are in close proximity with the TCJ proteins Gliotactin (Gli) and Bark Beetle (Bark), and both are required for TCJ protein recruitment. Loss of Bark or Gli led to basolateral spread of the TCJ complex at the cell corners. Loss of the septate junction proteins Nrx-IV and the Na+/K+ ATPase also resulted in basolateral spread of the entire TCJ complex at the cell corners. The Scrib PDZ1-2 domains and the Dlg GUK domain are necessary for Bark and Gli localization to the TCJ. Overall, we propose a model in which Scrib and Dlg are key components of the TCJ, and form a complex with Bark and Gli.
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Affiliation(s)
- Zohreh Sharifkhodaei
- Department of Zoology, University of British Columbia, Vancouver V6T 1Z4, Canada
| | - Mary M Gilbert
- Department of Zoology, University of British Columbia, Vancouver V6T 1Z4, Canada
| | - Vanessa J Auld
- Department of Zoology, University of British Columbia, Vancouver V6T 1Z4, Canada
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Pickett MA, Naturale VF, Feldman JL. A Polarizing Issue: Diversity in the Mechanisms Underlying Apico-Basolateral Polarization In Vivo. Annu Rev Cell Dev Biol 2019; 35:285-308. [PMID: 31461314 DOI: 10.1146/annurev-cellbio-100818-125134] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Polarization along an apico-basolateral axis is a hallmark of epithelial cells and is essential for their selective barrier and transporter functions, as well as for their ability to provide mechanical resiliency to organs. Loss of polarity along this axis perturbs development and is associated with a wide number of diseases. We describe three steps involved in polarization: symmetry breaking, polarity establishment, and polarity maintenance. While the proteins involved in these processes are highly conserved among epithelial tissues and species, the execution of these steps varies widely and is context dependent. We review both theoretical principles underlying these steps and recent work demonstrating how apico-basolateral polarity is established in vivo in different tissues, highlighting how developmental and physiological contexts play major roles in the execution of the epithelial polarity program.
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Affiliation(s)
- Melissa A Pickett
- Department of Biology, Stanford University, Stanford, California 94305, USA;
| | - Victor F Naturale
- Department of Biology, Stanford University, Stanford, California 94305, USA;
| | - Jessica L Feldman
- Department of Biology, Stanford University, Stanford, California 94305, USA;
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31
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Papagiannouli F, Berry CW, Fuller MT. The Dlg Module and Clathrin-Mediated Endocytosis Regulate EGFR Signaling and Cyst Cell-Germline Coordination in the Drosophila Testis. Stem Cell Reports 2019; 12:1024-1040. [PMID: 31006632 PMCID: PMC6523063 DOI: 10.1016/j.stemcr.2019.03.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 03/21/2019] [Accepted: 03/22/2019] [Indexed: 11/25/2022] Open
Abstract
Tissue homeostasis and repair relies on proper communication of stem cells and their differentiating daughters with the local tissue microenvironment. In the Drosophila male germline adult stem cell lineage, germ cells proliferate and progressively differentiate enclosed in supportive somatic cyst cells, forming a small organoid, the functional unit of differentiation. Here we show that cell polarity and vesicle trafficking influence signal transduction in cyst cells, with profound effects on the germ cells they enclose. Our data suggest that the cortical components Dlg, Scrib, Lgl and the clathrin-mediated endocytic (CME) machinery downregulate epidermal growth factor receptor (EGFR) signaling. Knockdown of dlg, scrib, lgl, or CME components in cyst cells resulted in germ cell death, similar to increased signal transduction via the EGFR, while lowering EGFR or downstream signaling components rescued the defects. This work provides insights into how cell polarity and endocytosis cooperate to regulate signal transduction and sculpt developing tissues. Dlg, Scrib, Lgl, and clathrin-mediated endocytosis (CME) attenuate EGFR signaling Knockdown of Dlg module or CME results in cell non-autonomous germ cell death Dlg module and CME control MAPK activation and the levels of the PIP2 phospholipid PIP2 and its synthesizing kinase Sktl/dPIP5K mediate MAPK activation
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Affiliation(s)
- Fani Papagiannouli
- Department of Developmental Biology, Beckman Center, Stanford University School of Medicine, Stanford, CA 94305-5329, USA; Institute for Genetics, University of Cologne, 50674 Cologne, Germany.
| | - Cameron Wynn Berry
- Department of Developmental Biology, Beckman Center, Stanford University School of Medicine, Stanford, CA 94305-5329, USA
| | - Margaret T Fuller
- Department of Developmental Biology, Beckman Center, Stanford University School of Medicine, Stanford, CA 94305-5329, USA
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32
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Regulation of Actin Dynamics in the C. elegans Somatic Gonad. J Dev Biol 2019; 7:jdb7010006. [PMID: 30897735 PMCID: PMC6473838 DOI: 10.3390/jdb7010006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 03/13/2019] [Accepted: 03/15/2019] [Indexed: 11/25/2022] Open
Abstract
The reproductive system of the hermaphroditic nematode C. elegans consists of a series of contractile cell types—including the gonadal sheath cells, the spermathecal cells and the spermatheca–uterine valve—that contract in a coordinated manner to regulate oocyte entry and exit of the fertilized embryo into the uterus. Contraction is driven by acto-myosin contraction and relies on the development and maintenance of specialized acto-myosin networks in each cell type. Study of this system has revealed insights into the regulation of acto-myosin network assembly and contractility in vivo.
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33
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Petri J, Syed MH, Rey S, Klämbt C. Non-Cell-Autonomous Function of the GPI-Anchored Protein Undicht during Septate Junction Assembly. Cell Rep 2019; 26:1641-1653.e4. [DOI: 10.1016/j.celrep.2019.01.046] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 12/12/2018] [Accepted: 01/10/2019] [Indexed: 11/26/2022] Open
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Drees L, Königsmann T, Jaspers MHJ, Pflanz R, Riedel D, Schuh R. Conserved function of the matriptase-prostasin proteolytic cascade during epithelial morphogenesis. PLoS Genet 2019; 15:e1007882. [PMID: 30601807 PMCID: PMC6331135 DOI: 10.1371/journal.pgen.1007882] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 01/14/2019] [Accepted: 12/06/2018] [Indexed: 01/08/2023] Open
Abstract
Extracellular matrix (ECM) assembly and remodelling is critical during development and organ morphogenesis. Dysregulation of ECM is implicated in many pathogenic conditions, including cancer. The type II transmembrane serine protease matriptase and the serine protease prostasin are key factors in a proteolytic cascade that regulates epithelial ECM differentiation during development in vertebrates. Here, we show by rescue experiments that the Drosophila proteases Notopleural (Np) and Tracheal-prostasin (Tpr) are functional homologues of matriptase and prostasin, respectively. Np mediates morphogenesis and remodelling of apical ECM during tracheal system development and is essential for maintenance of the transepithelial barrier function. Both Np and Tpr degrade the zona pellucida-domain (ZP-domain) protein Dumpy, a component of the transient tracheal apical ECM. Furthermore, we demonstrate that Tpr zymogen and the ZP domain of the ECM protein Piopio are cleaved by Np and matriptase in vitro. Our data indicate that the evolutionarily conserved ZP domain, present in many ECM proteins of vertebrates and invertebrates, is a novel target of the conserved matriptase-prostasin proteolytic cascade. Epithelial tissue covers the outside of the animal body and lines internal organs. Its disorganization is the source of approximately 90% of all human cancers. Elaboration of the basic epithelial characteristics has led to an understanding of how complex structures such as the branched tubular networks of vertebrate lung or invertebrate tracheal system are organized. Aside from obvious morphological differences, specific compositions of the epithelial extracellular matrix (ECM) have been noted. For example, while the flexible ECM of the vertebrate skin mainly consists of collagen and elastic fibers, the rigid ECM of invertebrates is chitin-based to serve as an inflexible exoskeleton. We show that a central regulator of ECM differentiation and epithelial development in vertebrates, the matriptase-prostasin proteolytic cascade (MPPC), is conserved and essential for both Drosophila ECM morphogenesis and physiology. The functionally conserved components of the MPPC mediate cleavage of zona pellucida-domain (ZP-domain) proteins, which play crucial roles in organizing apical structures of the ECM in both vertebrates and invertebrates. Our data indicate that ZP-proteins are molecular targets of the conserved MPPC and that cleavage within the ZP-domains is a conserved mechanism of ECM development and differentiation.
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Affiliation(s)
- Leonard Drees
- Research Group Molecular Organogenesis, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Tatiana Königsmann
- Research Group Molecular Organogenesis, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Martin H. J. Jaspers
- Research Group Molecular Organogenesis, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Ralf Pflanz
- Research Group Mass Spectrometry, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Dietmar Riedel
- Electron Microscopy Group, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Reinhard Schuh
- Research Group Molecular Organogenesis, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
- * E-mail:
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35
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Denecke S, Swevers L, Douris V, Vontas J. How do oral insecticidal compounds cross the insect midgut epithelium? INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2018; 103:22-35. [PMID: 30366055 DOI: 10.1016/j.ibmb.2018.10.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 10/09/2018] [Accepted: 10/21/2018] [Indexed: 06/08/2023]
Abstract
The use of oral insecticidal molecules (small molecules, peptides, dsRNA) via spray or plant mediated applications represents an efficient way to manage damaging insect species. With the exception of Bt toxins that target the midgut epithelium itself, most of these compounds have targets that lie within the hemocoel (body) of the insect. Because of this, one of the greatest factors in determining the effectiveness of an oral insecticidal compound is its ability to traverse the gut epithelium and enter the hemolymph. However, for many types of insecticidal compounds, neither the pathway taken across the gut nor the specific genes which influence uptake are fully characterized. Here, we review how different types of insecticidal compounds enter or cross the midgut epithelium through passive (diffusion) or active (transporter based, endocytosis) routes. A deeper understanding of how insecticidal molecules cross the gut will help to best utilize current insecticides and also provide for more rational design of future ones.
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Affiliation(s)
- Shane Denecke
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 73100, Heraklion, Greece.
| | - Luc Swevers
- Insect Molecular Genetics and Biotechnology Research Group, Institute of Biosciences & Applications, NCSR "Demokritos", Athens, Greece
| | - Vassilis Douris
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 73100, Heraklion, Greece
| | - John Vontas
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 73100, Heraklion, Greece; Department of Crop Science, Pesticide Science Lab, Agricultural University of Athens, Athens, Greece
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36
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Yildirim K, Petri J, Kottmeier R, Klämbt C. Drosophila glia: Few cell types and many conserved functions. Glia 2018; 67:5-26. [DOI: 10.1002/glia.23459] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/25/2018] [Accepted: 05/04/2018] [Indexed: 12/20/2022]
Affiliation(s)
- Kerem Yildirim
- Institute for Neuro and Behavioral Biology; University of Münster; Badestraße 9, 48149 Münster Germany
| | - Johanna Petri
- Institute for Neuro and Behavioral Biology; University of Münster; Badestraße 9, 48149 Münster Germany
| | - Rita Kottmeier
- Institute for Neuro and Behavioral Biology; University of Münster; Badestraße 9, 48149 Münster Germany
| | - Christian Klämbt
- Institute for Neuro and Behavioral Biology; University of Münster; Badestraße 9, 48149 Münster Germany
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37
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Babatz F, Naffin E, Klämbt C. The Drosophila Blood-Brain Barrier Adapts to Cell Growth by Unfolding of Pre-existing Septate Junctions. Dev Cell 2018; 47:697-710.e3. [PMID: 30482667 DOI: 10.1016/j.devcel.2018.10.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 08/07/2018] [Accepted: 10/01/2018] [Indexed: 12/18/2022]
Abstract
The blood-brain barrier is crucial for nervous system function. It is established early during development and stays intact during growth of the brain. In invertebrates, septate junctions are the occluding junctions of this barrier. Here, we used Drosophila to address how septate junctions grow during larval stages when brain size increases dramatically. We show that septate junctions are preassembled as long, highly folded strands during embryonic stages, connecting cell vertices. During subsequent cell growth, these corrugated strands are stretched out and stay intact during larval life with very little protein turnover. The G-protein coupled receptor Moody orchestrates the continuous organization of junctional strands in a process requiring F-actin. Consequently, in moody mutants, septate junction strands cannot properly stretch out during cell growth. To compensate for the loss of blood-brain barrier function, moody mutants form interdigitating cell-cell protrusions, resembling the evolutionary ancient barrier type found in primitive vertebrates or invertebrates such as cuttlefish.
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Affiliation(s)
- Felix Babatz
- University of Münster, Institute for Neuro and Behavioral Biology, Badestr. 9, 48149 Münster, Germany
| | - Elke Naffin
- University of Münster, Institute for Neuro and Behavioral Biology, Badestr. 9, 48149 Münster, Germany
| | - Christian Klämbt
- University of Münster, Institute for Neuro and Behavioral Biology, Badestr. 9, 48149 Münster, Germany.
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38
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Carvalho L, Patricio P, Ponte S, Heisenberg CP, Almeida L, Nunes AS, Araújo NAM, Jacinto A. Occluding junctions as novel regulators of tissue mechanics during wound repair. J Cell Biol 2018; 217:4267-4283. [PMID: 30228162 PMCID: PMC6279375 DOI: 10.1083/jcb.201804048] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 08/15/2018] [Accepted: 09/05/2018] [Indexed: 01/02/2023] Open
Abstract
Simple epithelial repair is mediated by the contraction of an actomyosin cable and cellular rearrangements at the wound edge. Carvalho et al. show that occluding junctions are required for epithelial repair by regulating these cellular rearrangements and tissue mechanical properties. In epithelial tissues, cells tightly connect to each other through cell–cell junctions, but they also present the remarkable capacity of reorganizing themselves without compromising tissue integrity. Upon injury, simple epithelia efficiently resolve small lesions through the action of actin cytoskeleton contractile structures at the wound edge and cellular rearrangements. However, the underlying mechanisms and how they cooperate are still poorly understood. In this study, we combine live imaging and theoretical modeling to reveal a novel and indispensable role for occluding junctions (OJs) in this process. We demonstrate that OJ loss of function leads to defects in wound-closure dynamics: instead of contracting, wounds dramatically increase their area. OJ mutants exhibit phenotypes in cell shape, cellular rearrangements, and mechanical properties as well as in actin cytoskeleton dynamics at the wound edge. We propose that OJs are essential for wound closure by impacting on epithelial mechanics at the tissue level, which in turn is crucial for correct regulation of the cellular events occurring at the wound edge.
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Affiliation(s)
- Lara Carvalho
- Chronic Diseases Research Center, NOVA Medical School/Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisbon, Portugal
| | - Pedro Patricio
- Chronic Diseases Research Center, NOVA Medical School/Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisbon, Portugal.,Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, Lisbon, Portugal.,Centro de Física Teórica e Computacional, Universidade de Lisboa, Campo Grande, Lisbon, Portugal
| | - Susana Ponte
- Chronic Diseases Research Center, NOVA Medical School/Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisbon, Portugal
| | | | - Luis Almeida
- Centre National de la Recherche Scientifique/Sorbonne Université/Team Mamba, French Institute for Research in Computer Science and Automation Paris, Laboratoire Jacques-Louis Lions, BC187, Paris, France
| | - André S Nunes
- Centro de Física Teórica e Computacional, Universidade de Lisboa, Campo Grande, Lisbon, Portugal.,Departamento de Física, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Lisbon, Portugal
| | - Nuno A M Araújo
- Centro de Física Teórica e Computacional, Universidade de Lisboa, Campo Grande, Lisbon, Portugal.,Departamento de Física, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Lisbon, Portugal
| | - Antonio Jacinto
- Chronic Diseases Research Center, NOVA Medical School/Faculdade de Ciências Médicas, Universidade NOVA de Lisboa, Lisbon, Portugal .,The Discoveries Centre for Regenerative and Precision Medicine, Universidade NOVA de Lisboa, Lisbon, Portugal
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39
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Daniel E, Daudé M, Kolotuev I, Charish K, Auld V, Le Borgne R. Coordination of Septate Junctions Assembly and Completion of Cytokinesis in Proliferative Epithelial Tissues. Curr Biol 2018; 28:1380-1391.e4. [PMID: 29706514 DOI: 10.1016/j.cub.2018.03.034] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 12/26/2017] [Accepted: 03/15/2018] [Indexed: 01/22/2023]
Abstract
How permeability barrier function is maintained when epithelial cells divide is largely unknown. Here, we have investigated how the bicellular septate junctions (BSJs) and tricellular septate junctions (TSJs) are remodeled throughout completion of cytokinesis in Drosophila epithelia. We report that, following cytokinetic ring constriction, the midbody assembles, matures within SJs, and is displaced basally in two phases. In a first slow phase, the neighboring cells remain connected to the dividing cells by means of SJ-containing membrane protrusions pointing to the maturing midbody. Fluorescence recovery after photobleaching (FRAP) experiments revealed that SJs within the membrane protrusions correspond to the old SJs that were present prior to cytokinesis. In contrast, new SJs are assembled below the adherens junctions and spread basally to build a new belt of SJs in a manner analogous to a conveyor belt. Loss of function of a core BSJ component, the Na+/K+-ATPase pump Nervana 2 subunit, revealed that the apical-to-basal spread of BSJs drives the basal displacement of the midbody. In contrast, loss of the TSJ protein Bark beetle indicated that remodeling of TSJs is rate limiting and slowed down midbody migration. In the second phase, once the belt of SJs is assembled, the basal displacement of the midbody is accelerated and ultimately leads to abscission. This last step is temporally uncoupled from the remodeling of SJs. We propose that cytokinesis in epithelia involves the coordinated polarized assembly and remodeling of SJs both in the dividing cell and its neighbors to ensure the maintenance of permeability barrier integrity in proliferative epithelia.
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Affiliation(s)
- Emeline Daniel
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, 35000 Rennes, France
| | - Marion Daudé
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, 35000 Rennes, France
| | - Irina Kolotuev
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, 35000 Rennes, France
| | - Kristi Charish
- Department of Zoology, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Vanessa Auld
- Department of Zoology, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
| | - Roland Le Borgne
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, 35000 Rennes, France; Équipe Labellisée Ligue Nationale contre le Cancer.
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40
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Volkenhoff A, Hirrlinger J, Kappel JM, Klämbt C, Schirmeier S. Live imaging using a FRET glucose sensor reveals glucose delivery to all cell types in the Drosophila brain. JOURNAL OF INSECT PHYSIOLOGY 2018; 106:55-64. [PMID: 28733241 DOI: 10.1016/j.jinsphys.2017.07.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 06/13/2017] [Accepted: 07/17/2017] [Indexed: 05/26/2023]
Abstract
All complex nervous systems are metabolically separated from circulation by a blood-brain barrier (BBB) that prevents uncontrolled leakage of solutes into the brain. Thus, all metabolites needed to sustain energy homeostasis must be transported across this BBB. In invertebrates, such as Drosophila, the major carbohydrate in circulation is the disaccharide trehalose and specific trehalose transporters are expressed by the glial BBB. Here we analyzed whether glucose is able to contribute to energy homeostasis in Drosophila. To study glucose influx into the brain we utilized a genetically encoded, FRET-based glucose sensor expressed in a cell type specific manner. When confronted with glucose all brain cells take up glucose within two minutes. In order to characterize the glucose transporter involved, we studied Drosophila Glut1, the homologue of which is primarily expressed by the BBB-forming endothelial cells and astrocytes in the mammalian nervous system. In Drosophila, however, Glut1 is expressed in neurons and is not found at the BBB. Thus, Glut1 cannot contribute to initial glucose uptake from the hemolymph. To test whether gap junctional coupling between the BBB forming cells and other neural cells contributes to glucose distribution we assayed these junctions using RNAi experiments and only found a minor contribution of gap junctions to glucose metabolism. Our results provide the entry point to further dissect the mechanisms underlying glucose distribution and offer new opportunities to understand brain metabolism.
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Affiliation(s)
- Anne Volkenhoff
- Institut für Neuro- und Verhaltensbiologie, Badestr. 9, 48149 Münster, Germany
| | - Johannes Hirrlinger
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig, Liebigstr. 27, D-04103 Leipzig, Germany; Department of Neurogenetics, Max-Planck-Institute for Experimental Medicine, Hermann-Rein-Str. 3, D-37075 Göttingen, Germany
| | - Johannes M Kappel
- Institut für Neuro- und Verhaltensbiologie, Badestr. 9, 48149 Münster, Germany
| | - Christian Klämbt
- Institut für Neuro- und Verhaltensbiologie, Badestr. 9, 48149 Münster, Germany
| | - Stefanie Schirmeier
- Institut für Neuro- und Verhaltensbiologie, Badestr. 9, 48149 Münster, Germany.
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41
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Tempesta C, Hijazi A, Moussian B, Roch F. Boudin trafficking reveals the dynamic internalisation of specific septate junction components in Drosophila. PLoS One 2017; 12:e0185897. [PMID: 28977027 PMCID: PMC5627947 DOI: 10.1371/journal.pone.0185897] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/21/2017] [Indexed: 11/18/2022] Open
Abstract
The maintenance of paracellular barriers in invertebrate epithelia depends on the integrity of specific cell adhesion structures known as septate junctions (SJ). Multiple studies in Drosophila have revealed that these junctions have a stereotyped architecture resulting from the association in the lateral membrane of a large number of components. However, little is known about the dynamic organisation adopted by these multi-protein complexes in living tissues. We have used live imaging techniques to show that the Ly6 protein Boudin is a component of these adhesion junctions and can diffuse systemically to associate with the SJ of distant cells. We also observe that this protein and the claudin Kune-kune are endocytosed in epidermal cells during embryogenesis. Our data reveal that the SJ contain a set of components exhibiting a high membrane turnover, a feature that could contribute in a tissue-specific manner to the morphogenetic plasticity of these adhesion structures.
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Affiliation(s)
- Camille Tempesta
- Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Assia Hijazi
- Lebanese University, Faculty of Sciences I and V—Doctorate School of Science and Technology-PRASE, Campus Rafic Hariri, Hadath-Beirut, Lebanon
| | - Bernard Moussian
- University of Tübingen, Interfaculty Institute of Cell Biology, Section Animal Genetics, Tübingen, Germany
| | - Fernando Roch
- Centre de Biologie du Développement (CBD), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, UPS, Toulouse, France
- * E-mail:
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42
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Schwabe T, Li X, Gaul U. Dynamic analysis of the mesenchymal-epithelial transition of blood-brain barrier forming glia in Drosophila. Biol Open 2017; 6:232-243. [PMID: 28108476 PMCID: PMC5312092 DOI: 10.1242/bio.020669] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
During development, many epithelia are formed by a mesenchymal-epithelial transition (MET). Here, we examine the major stages and underlying mechanisms of MET during blood-brain barrier formation in Drosophila. We show that contact with the basal lamina is essential for the growth of the barrier-forming subperineurial glia (SPG). Septate junctions (SJs), which provide insulation of the paracellular space, are not required for MET, but are necessary for the establishment of polarized SPG membrane compartments. In vivo time-lapse imaging reveals that the Moody GPCR signaling pathway regulates SPG cell growth and shape, with different levels of signaling causing distinct phenotypes. Timely, well-coordinated SPG growth is essential for the uniform insertion of SJs and thus the insulating function of the barrier. To our knowledge, this is the first dynamic in vivo analysis of all stages in the formation of a secondary epithelium, and of the key role trimeric G protein signaling plays in this important morphogenetic process. Summary: This study examines the major steps and underlying mechanisms of mesenchymal-epithelial transition of the blood-brain-barrier forming glia in Drosophila, including the role of basal lamina, septate junctions and of trimeric G protein signaling.
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Affiliation(s)
- Tina Schwabe
- Department of Biochemistry, Gene Center, Center of Integrated Protein Science (CIPSM), University of Munich, Feodor-Lynen-Str. 25, Munich 81377, Germany
| | - Xiaoling Li
- Department of Biochemistry, Gene Center, Center of Integrated Protein Science (CIPSM), University of Munich, Feodor-Lynen-Str. 25, Munich 81377, Germany.,Rockefeller University, 1230 York Ave, New York, 10065-6399 NY, USA
| | - Ulrike Gaul
- Department of Biochemistry, Gene Center, Center of Integrated Protein Science (CIPSM), University of Munich, Feodor-Lynen-Str. 25, Munich 81377, Germany
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43
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Localized, Reactive F-Actin Dynamics Prevents Abnormal Somatic Cell Penetration by Mature Spermatids. Dev Cell 2016; 38:507-21. [DOI: 10.1016/j.devcel.2016.07.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 04/15/2016] [Accepted: 07/01/2016] [Indexed: 12/15/2022]
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44
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Fairchild MJ, Yang L, Goodwin K, Tanentzapf G. Occluding Junctions Maintain Stem Cell Niche Homeostasis in the Fly Testes. Curr Biol 2016; 26:2492-2499. [PMID: 27546574 DOI: 10.1016/j.cub.2016.07.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 05/23/2016] [Accepted: 07/08/2016] [Indexed: 12/16/2022]
Abstract
Stem cells can be controlled by their local microenvironment, known as the stem cell niche. The Drosophila testes contain a morphologically distinct niche called the hub, composed of a cluster of between 8 and 20 cells known as hub cells, which contact and regulate germline stem cells (GSCs) and somatic cyst stem cells (CySCs). Both hub cells and CySCs originate from somatic gonadal precursor cells during embryogenesis, but whereas hub cells, once specified, cease all mitotic activity, CySCs remain mitotic into adulthood [1, 2]. Cyst cells, derived from the CySCs, first encapsulate the germline and then, using occluding junctions, form an isolating permeability barrier [3]. This barrier promotes germline differentiation by excluding niche-derived stem cell maintenance factors. Here, we show that the somatic permeability barrier is also required to regulate stem cell niche homeostasis. Loss of occluding junction components in the somatic cells results in hub overgrowth. Enlarged hubs are active and recruit more GSCs and CySCs to the niche. Surprisingly, hub growth results from depletion of occluding junction components in cyst cells, not from depletion in the hub cells themselves. Moreover, hub growth is caused by incorporation of cells that previously expressed markers for cyst cells and not by hub cell proliferation. Importantly, depletion of occluding junctions disrupts Notch and mitogen-activated protein kinase (MAPK) signaling, and hub overgrowth defects are partially rescued by modulation of either signaling pathway. Overall, these data show that occluding junctions shape the signaling environment between the soma and the germline in order to maintain niche homeostasis.
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Affiliation(s)
- Michael J Fairchild
- Department of Cellular and Physiological Sciences, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Lulu Yang
- Department of Cellular and Physiological Sciences, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Katharine Goodwin
- Department of Cellular and Physiological Sciences, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Guy Tanentzapf
- Department of Cellular and Physiological Sciences, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada.
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45
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Harden N, Wang SJH, Krieger C. Making the connection – shared molecular machinery and evolutionary links underlie the formation and plasticity of occluding junctions and synapses. J Cell Sci 2016; 129:3067-76. [DOI: 10.1242/jcs.186627] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
ABSTRACT
The pleated septate junction (pSJ), an ancient structure for cell–cell contact in invertebrate epithelia, has protein components that are found in three more-recent junctional structures, the neuronal synapse, the paranodal region of the myelinated axon and the vertebrate epithelial tight junction. These more-recent structures appear to have evolved through alterations of the ancestral septate junction. During its formation in the developing animal, the pSJ exhibits plasticity, although the final structure is extremely robust. Similar to the immature pSJ, the synapse and tight junctions both exhibit plasticity, and we consider evidence that this plasticity comes at least in part from the interaction of members of the immunoglobulin cell adhesion molecule superfamily with highly regulated membrane-associated guanylate kinases. This plasticity regulation probably arose in order to modulate the ancestral pSJ and is maintained in the derived structures; we suggest that it would be beneficial when studying plasticity of one of these structures to consider the literature on the others. Finally, looking beyond the junctions, we highlight parallels between epithelial and synaptic membranes, which both show a polarized distribution of many of the same proteins – evidence that determinants of apicobasal polarity in epithelia also participate in patterning of the synapse.
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Affiliation(s)
- Nicholas Harden
- Simon Fraser University, Department of Molecular Biology and Biochemistry, Burnaby, British Columbia V5A 1S6, Canada
| | - Simon Ji Hau Wang
- Simon Fraser University, Department of Molecular Biology and Biochemistry, Burnaby, British Columbia V5A 1S6, Canada
- Simon Fraser University, Department of Biomedical Physiology and Kinesiology, Burnaby, British Columbia V5A 1S6, Canada
| | - Charles Krieger
- Simon Fraser University, Department of Biomedical Physiology and Kinesiology, Burnaby, British Columbia V5A 1S6, Canada
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46
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Yamazaki Y, Palmer L, Alexandre C, Kakugawa S, Beckett K, Gaugue I, Palmer RH, Vincent JP. Godzilla-dependent transcytosis promotes Wingless signalling in Drosophila wing imaginal discs. Nat Cell Biol 2016; 18:451-7. [PMID: 26974662 PMCID: PMC4817240 DOI: 10.1038/ncb3325] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 02/05/2016] [Indexed: 12/18/2022]
Abstract
The apical and basolateral membranes of epithelia are insulated from each other, preventing the transfer of extracellular proteins from one side to the other. Thus, a signalling protein produced apically is not expected to reach basolateral receptors. Evidence suggests that Wingless, the main Drosophila Wnt, is secreted apically in the embryonic epidermis. However, in the wing imaginal disc epithelium, Wingless is mostly seen on the basolateral membrane where it spreads from secreting to receiving cells. Here we examine the apico-basal movement of Wingless in Wingless-producing cells of wing imaginal discs. We find that it is presented first on the apical surface before making its way to the basolateral surface, where it is released and allowed to interact with signalling receptors. We show that Wingless transcytosis involves dynamin-dependent endocytosis from the apical surface. Subsequent trafficking from early apical endosomes to the basolateral surface requires Godzilla, a member of the RNF family of membrane-anchored E3 ubiquitin ligases. Without such transport, Wingless signalling is strongly reduced in this tissue.
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Affiliation(s)
- Yasuo Yamazaki
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, The Sahlgrenska Academy at the University of Gothenburg, Medicinaregatan 9A, 40539 Gothenburg, Sweden
| | - Lucy Palmer
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Cyrille Alexandre
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Satoshi Kakugawa
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Karen Beckett
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Isabelle Gaugue
- Polarity, Division and Morphogenesis Team, Institut Curie, CNRS UMR 3215, INSERM U934, 26 rue d'Ulm, 75248 Paris Cedex 05, France
| | - Ruth H Palmer
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, The Sahlgrenska Academy at the University of Gothenburg, Medicinaregatan 9A, 40539 Gothenburg, Sweden
| | - Jean-Paul Vincent
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London NW7 1AA, UK
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47
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Woichansky I, Beretta CA, Berns N, Riechmann V. Three mechanisms control E-cadherin localization to the zonula adherens. Nat Commun 2016; 7:10834. [PMID: 26960923 PMCID: PMC4792928 DOI: 10.1038/ncomms10834] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 01/25/2016] [Indexed: 12/13/2022] Open
Abstract
E-cadherin localization to the zonula adherens is fundamental for epithelial differentiation but the mechanisms controlling localization are unclear. Using the Drosophila follicular epithelium we genetically dissect E-cadherin transport in an in vivo model. We distinguish three mechanisms mediating E-cadherin accumulation at the zonula adherens. Two membrane trafficking pathways deliver newly synthesized E-cadherin to the plasma membrane. One is Rab11 dependent and targets E-cadherin directly to the zonula adherens, while the other transports E-cadherin to the lateral membrane. Lateral E-cadherin reaches the zonula adherens by endocytosis and targeted recycling. We show that this pathway is dependent on RabX1, which provides a functional link between early and recycling endosomes. Moreover, we show that lateral E-cadherin is transported to the zonula adherens by an apically directed flow within the plasma membrane. Differential activation of these pathways could facilitate cell shape changes during morphogenesis, while their misregulation compromises cell adhesion and tissue architecture in differentiated epithelia.
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Affiliation(s)
- Innokenty Woichansky
- Department of Cell and Molecular Biology and Division of Signaling and Functional Genomics at the German Cancer Research Center (DKFZ), Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Strasse 13-17, D-68167 Mannheim, Germany
| | - Carlo Antonio Beretta
- Heidelberg University, COS and Nikon Imaging Center at the University of Heidelberg, Bioquant, D-69120 Heidelberg, Germany
- Excellenzcluster CellNetworks, University of Heidelberg, D-69120 Heidelberg, Germany
| | - Nicola Berns
- Department of Cell and Molecular Biology and Division of Signaling and Functional Genomics at the German Cancer Research Center (DKFZ), Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Strasse 13-17, D-68167 Mannheim, Germany
| | - Veit Riechmann
- Department of Cell and Molecular Biology and Division of Signaling and Functional Genomics at the German Cancer Research Center (DKFZ), Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Strasse 13-17, D-68167 Mannheim, Germany
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48
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Sharifkhodaei Z, Padash-Barmchi M, Gilbert MM, Samarasekera G, Fulga TA, Van Vactor D, Auld VJ. The Drosophila tricellular junction protein Gliotactin regulates its own mRNA levels through BMP-mediated induction of miR-184. J Cell Sci 2016; 129:1477-89. [PMID: 26906422 DOI: 10.1242/jcs.178608] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 02/11/2016] [Indexed: 12/19/2022] Open
Abstract
Epithelial bicellular and tricellular junctions are essential for establishing and maintaining permeability barriers. Tricellular junctions are formed by the convergence of three bicellular junctions at the corners of neighbouring epithelia. Gliotactin, a member of the Neuroligin family, is located at theDrosophilatricellular junction, and is crucial for the formation of tricellular and septate junctions, as well as permeability barrier function. Gliotactin protein levels are tightly controlled by phosphorylation at tyrosine residues and endocytosis. Blocking endocytosis or overexpressing Gliotactin results in the spread of Gliotactin from the tricellular junction, resulting in apoptosis, delamination and migration of epithelial cells. We show that Gliotactin levels are also regulated at the mRNA level by micro (mi)RNA-mediated degradation and that miRNAs are targeted to a short region in the 3'UTR that includes a conserved miR-184 target site. miR-184 also targets a suite of septate junction proteins, including NrxIV, coracle and Mcr. miR-184 expression is triggered when Gliotactin is overexpressed, leading to activation of the BMP signalling pathway. Gliotactin specifically interferes with Dad, an inhibitory SMAD, leading to activation of the Tkv type-I receptor and activation of Mad to elevate the biogenesis and expression of miR-184.
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Affiliation(s)
- Zohreh Sharifkhodaei
- Department of Zoology, University of British Columbia, Vancouver BC V6T 1Z3, Canada
| | | | - Mary M Gilbert
- Department of Zoology, University of British Columbia, Vancouver BC V6T 1Z3, Canada
| | | | - Tudor A Fulga
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - David Van Vactor
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Vanessa J Auld
- Department of Zoology, University of British Columbia, Vancouver BC V6T 1Z3, Canada
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49
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Deligiannaki M, Casper AL, Jung C, Gaul U. Pasiflora proteins are novel core components of the septate junction. Development 2015; 142:3046-57. [PMID: 26329602 PMCID: PMC4582180 DOI: 10.1242/dev.119412] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Epithelial sheets play essential roles as selective barriers insulating the body from the environment and establishing distinct chemical compartments within it. In invertebrate epithelia, septate junctions (SJs) consist of large multi-protein complexes that localize at the apicolateral membrane and mediate barrier function. Here, we report the identification of two novel SJ components, Pasiflora1 and Pasiflora2, through a genome-wide glial RNAi screen in Drosophila. Pasiflora mutants show permeable blood-brain and tracheal barriers, overelongated tracheal tubes and mislocalization of SJ proteins. Consistent with the observed phenotypes, the genes are co-expressed in embryonic epithelia and glia and are required cell-autonomously to exert their function. Pasiflora1 and Pasiflora2 belong to a previously uncharacterized family of tetraspan membrane proteins conserved across the protostome-deuterostome divide. Both proteins localize at SJs and their apicolateral membrane accumulation depends on other complex components. In fluorescence recovery after photobleaching experiments we demonstrate that pasiflora proteins are core SJ components as they are required for complex formation and exhibit restricted mobility within the membrane of wild-type epithelial cells, but rapid diffusion in cells with disrupted SJs. Taken together, our results show that Pasiflora1 and Pasiflora2 are novel integral components of the SJ and implicate a new family of tetraspan proteins in the function of these ancient and crucial cell junctions.
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Affiliation(s)
- Myrto Deligiannaki
- Gene Center, Department of Biochemistry, Center of Protein Science CIPSM, Ludwigs-Maximilians University, Feodor-Lynen-Str. 25, Munich 81377, Germany
| | - Abbie L Casper
- Gene Center, Department of Biochemistry, Center of Protein Science CIPSM, Ludwigs-Maximilians University, Feodor-Lynen-Str. 25, Munich 81377, Germany
| | - Christophe Jung
- Gene Center, Department of Biochemistry, Center of Protein Science CIPSM, Ludwigs-Maximilians University, Feodor-Lynen-Str. 25, Munich 81377, Germany
| | - Ulrike Gaul
- Gene Center, Department of Biochemistry, Center of Protein Science CIPSM, Ludwigs-Maximilians University, Feodor-Lynen-Str. 25, Munich 81377, Germany
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50
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Occluding junctions of invertebrate epithelia. J Comp Physiol B 2015; 186:17-43. [DOI: 10.1007/s00360-015-0937-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 09/12/2015] [Accepted: 09/22/2015] [Indexed: 01/30/2023]
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