1
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Pinot M, Le Borgne R. Spatio-Temporal Regulation of Notch Activation in Asymmetrically Dividing Sensory Organ Precursor Cells in Drosophila melanogaster Epithelium. Cells 2024; 13:1133. [PMID: 38994985 PMCID: PMC11240559 DOI: 10.3390/cells13131133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2024] [Revised: 06/24/2024] [Accepted: 06/25/2024] [Indexed: 07/13/2024] Open
Abstract
The Notch communication pathway, discovered in Drosophila over 100 years ago, regulates a wide range of intra-lineage decisions in metazoans. The division of the Drosophila mechanosensory organ precursor is the archetype of asymmetric cell division in which differential Notch activation takes place at cytokinesis. Here, we review the molecular mechanisms by which epithelial cell polarity, cell cycle and intracellular trafficking participate in controlling the directionality, subcellular localization and temporality of mechanosensitive Notch receptor activation in cytokinesis.
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Affiliation(s)
| | - Roland Le Borgne
- Univ Rennes, Centre National de la Recherche Scientifique UMR 6290, IGDR (Institut de Génétique et Développement de Rennes), F-35000 Rennes, France
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2
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Contreras EG, Kautzmann S, Klämbt C. The Drosophila blood-brain barrier invades the nervous system in a GPCR-dependent manner. Front Cell Neurosci 2024; 18:1397627. [PMID: 38846639 PMCID: PMC11153769 DOI: 10.3389/fncel.2024.1397627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Accepted: 05/07/2024] [Indexed: 06/09/2024] Open
Abstract
The blood-brain barrier (BBB) represents a crucial interface between the circulatory system and the brain. In Drosophila melanogaster, the BBB is composed of perineurial and subperineurial glial cells. The perineurial glial cells are small mitotically active cells forming the outermost layer of the nervous system and are engaged in nutrient uptake. The subperineurial glial cells form occluding septate junctions to prevent paracellular diffusion of macromolecules into the nervous system. To address whether the subperineurial glia just form a simple barrier or whether they establish specific contacts with both the perineurial glial cells and inner central nervous system (CNS) cells, we undertook a detailed morphological analysis. Using genetically encoded markers alongside with high-resolution laser scanning confocal microscopy and transmission electron microscopy, we identified thin cell processes extending into the perineurial layer and into the CNS cortex. Interestingly, long cell processes were observed reaching the glia ensheathing the neuropil of the central brain. GFP reconstitution experiments highlighted multiple regions of membrane contacts between subperineurial and ensheathing glia. Furthermore, we identify the G-protein-coupled receptor (GPCR) Moody as negative regulator of the growth of subperineurial cell processes. Loss of moody triggered a massive overgrowth of subperineurial cell processes into the CNS cortex and, moreover, affected the polarized localization of the xenobiotic transporter Mdr65. Finally, we found that GPCR signaling, but not septate junction formation, is responsible for controlling membrane overgrowth. Our findings support the notion that the Drosophila BBB is able to bridge the communication gap between circulation and synaptic regions of the brain by long cell processes.
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Affiliation(s)
| | | | - Christian Klämbt
- Multiscale Imaging Center, Institute of Neuro- and Behavioral Biology, University of Münster, Münster, Germany
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3
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Banach-Latapy A, Rincheval V, Briand D, Guénal I, Spéder P. Differential adhesion during development establishes individual neural stem cell niches and shapes adult behaviour in Drosophila. PLoS Biol 2023; 21:e3002352. [PMID: 37943883 PMCID: PMC10635556 DOI: 10.1371/journal.pbio.3002352] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 09/28/2023] [Indexed: 11/12/2023] Open
Abstract
Neural stem cells (NSCs) reside in a defined cellular microenvironment, the niche, which supports the generation and integration of newborn neurons. The mechanisms building a sophisticated niche structure around NSCs and their functional relevance for neurogenesis are yet to be understood. In the Drosophila larval brain, the cortex glia (CG) encase individual NSC lineages in membranous chambers, organising the stem cell population and newborn neurons into a stereotypic structure. We first found that CG wrap around lineage-related cells regardless of their identity, showing that lineage information builds CG architecture. We then discovered that a mechanism of temporally controlled differential adhesion using conserved complexes supports the individual encasing of NSC lineages. An intralineage adhesion through homophilic Neuroglian interactions provides strong binding between cells of a same lineage, while a weaker interaction through Neurexin-IV and Wrapper exists between NSC lineages and CG. Loss of Neuroglian results in NSC lineages clumped together and in an altered CG network, while loss of Neurexin-IV/Wrapper generates larger yet defined CG chamber grouping several lineages together. Axonal projections of newborn neurons are also altered in these conditions. Further, we link the loss of these 2 adhesion complexes specifically during development to locomotor hyperactivity in the resulting adults. Altogether, our findings identify a belt of adhesions building a neurogenic niche at the scale of individual stem cell and provide the proof of concept that niche properties during development shape adult behaviour.
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Affiliation(s)
- Agata Banach-Latapy
- Institut Pasteur, Université Paris Cité, CNRS UMR3738, Structure and Signals in the Neurogenic Niche, Paris, France
| | | | - David Briand
- Institut Pasteur, Université Paris Cité, CNRS UMR3738, Structure and Signals in the Neurogenic Niche, Paris, France
| | - Isabelle Guénal
- Université Paris-Saclay, UVSQ, LGBC, 78000, Versailles, France
| | - Pauline Spéder
- Institut Pasteur, Université Paris Cité, CNRS UMR3738, Structure and Signals in the Neurogenic Niche, Paris, France
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4
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Bresnahan ST, Galbraith D, Ma R, Anton K, Rangel J, Grozinger CM. Beyond conflict: Kinship theory of intragenomic conflict predicts individual variation in altruistic behaviour. Mol Ecol 2023; 32:5823-5837. [PMID: 37746895 DOI: 10.1111/mec.17145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 09/08/2023] [Accepted: 09/11/2023] [Indexed: 09/26/2023]
Abstract
Behavioural variation is essential for animals to adapt to different social and environmental conditions. The Kinship Theory of Intragenomic Conflict (KTIC) predicts that parent-specific alleles can support different behavioural strategies to maximize allele fitness. Previous studies, including in honey bees (Apis mellifera), supported predictions of the KTIC for parent-specific alleles to promote selfish behaviour. Here, we test the KTIC prediction that for altruism-promoting genes (i.e. those that promote behaviours that support the reproductive fitness of kin), the allele with the higher altruism optimum should be selected to be expressed while the other is silenced. In honey bee colonies, workers act altruistically when tending to the queen by performing a 'retinue' behaviour, distributing the queen's mandibular pheromone (QMP) throughout the hive. Workers exposed to QMP do not activate their ovaries, ensuring they care for the queen's brood instead of competing to lay unfertilized eggs. Due to the haplodiploid genetics of honey bees, the KTIC predicts that response to QMP is favoured by the maternal genome. We report evidence for parent-of-origin effects on the retinue response behaviour, ovarian development and gene expression in brains of worker honey bees exposed to QMP, consistent with the KTIC. Additionally, we show enrichment for genes with parent-of-origin expression bias within gene regulatory networks associated with variation in bees' response to QMP. Our study demonstrates that intragenomic conflict can shape diverse social behaviours and influence expression patterns of single genes as well as gene networks.
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Affiliation(s)
- Sean T Bresnahan
- Department of Entomology, Center for Pollinator Research, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
- Intercollege Graduate Degree Program in Molecular, Cellular, and Integrative Biosciences, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - David Galbraith
- Department of Entomology, Center for Pollinator Research, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Rong Ma
- Department of Entomology, Center for Pollinator Research, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Kate Anton
- Department of Entomology, Center for Pollinator Research, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Juliana Rangel
- Department of Entomology, Texas A&M University, College Station, Texas, USA
| | - Christina M Grozinger
- Department of Entomology, Center for Pollinator Research, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, Pennsylvania, USA
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5
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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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6
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Daeden A, Mietke A, Derivery E, Seum C, Jülicher F, Gonzalez-Gaitan M. Polarized branched Actin modulates cortical mechanics to produce unequal-size daughters during asymmetric division. Nat Cell Biol 2023; 25:235-245. [PMID: 36747081 PMCID: PMC9928585 DOI: 10.1038/s41556-022-01058-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 11/22/2022] [Indexed: 02/08/2023]
Abstract
The control of cell shape during cytokinesis requires a precise regulation of mechanical properties of the cell cortex. Only few studies have addressed the mechanisms underlying the robust production of unequal-sized daughters during asymmetric cell division. Here we report that unequal daughter-cell sizes resulting from asymmetric sensory organ precursor divisions in Drosophila are controlled by the relative amount of cortical branched Actin between the two cell poles. We demonstrate this by mistargeting the machinery for branched Actin dynamics using nanobodies and optogenetics. We can thereby engineer the cell shape with temporal precision and thus the daughter-cell size at different stages of cytokinesis. Most strikingly, inverting cortical Actin asymmetry causes an inversion of daughter-cell sizes. Our findings uncover the physical mechanism by which the sensory organ precursor mother cell controls relative daughter-cell size: polarized cortical Actin modulates the cortical bending rigidity to set the cell surface curvature, stabilize the division and ultimately lead to unequal daughter-cell size.
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Affiliation(s)
- Alicia Daeden
- Department of Biochemistry, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Alexander Mietke
- Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Center for Systems Biology Dresden, Dresden, Germany
| | - Emmanuel Derivery
- Department of Biochemistry, Faculty of Sciences, University of Geneva, Geneva, Switzerland
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Carole Seum
- Department of Biochemistry, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Frank Jülicher
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - Marcos Gonzalez-Gaitan
- Department of Biochemistry, Faculty of Sciences, University of Geneva, Geneva, Switzerland.
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7
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The Multitasker Protein: A Look at the Multiple Capabilities of NUMB. Cells 2023; 12:cells12020333. [PMID: 36672267 PMCID: PMC9856935 DOI: 10.3390/cells12020333] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/08/2023] [Accepted: 01/13/2023] [Indexed: 01/18/2023] Open
Abstract
NUMB, a plasma membrane-associated protein originally described in Drosophila, is involved in determining cell function and fate during early stages of development. It is secreted asymmetrically in dividing cells, with one daughter cell inheriting NUMB and the other inheriting its antagonist, NOTCH. NUMB has been proposed as a polarizing agent and has multiple functions, including endocytosis and serving as an adaptor in various cellular pathways such as NOTCH, Hedgehog, and the P53-MDM2 axis. Due to its role in maintaining cellular homeostasis, it has been suggested that NUMB may be involved in various human pathologies such as cancer and Alzheimer's disease. Further research on NUMB could aid in understanding disease mechanisms and advancing the field of personalized medicine and the development of new therapies.
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8
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Zamfirescu AM, Yatsenko AS, Shcherbata HR. Notch signaling sculpts the stem cell niche. Front Cell Dev Biol 2022; 10:1027222. [PMID: 36605720 PMCID: PMC9810114 DOI: 10.3389/fcell.2022.1027222] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 12/02/2022] [Indexed: 12/24/2022] Open
Abstract
Adult stem cells depend on their niches for regulatory signaling that controls their maintenance, division, and their progeny differentiation. While communication between various types of stem cells and their niches is becoming clearer, the process of stem cell niche establishment is still not very well understood. Model genetic organisms provide simplified systems to address various complex questions, for example, how is a stem cell niche formed? What signaling cascades induce the stem cell niche formation? Are the mechanisms of stem cell niche formation conserved? Notch signaling is an evolutionarily conserved pathway first identified in fruit flies, crucial in fate acquisition and spatiotemporal patterning. While the core logic behind its activity is fairly simple and requires direct cell-cell interaction, it reaches an astonishing complexity and versatility by combining its different modes of action. Subtleties such as equivalency between communicating cells, their physical distance, receptor and ligand processing, and endocytosis can have an effect on the way the events unfold, and this review explores some important general mechanisms of action, later on focusing on its involvement in stem cell niche formation. First, looking at invertebrates, we will examine how Notch signaling induces the formation of germline stem cell niche in male and female Drosophila. In the developing testis, a group of somatic gonadal precursor cells receive Delta signals from the gut, activating Notch signaling and sealing their fate as niche cells even before larval hatching. Meanwhile, the ovarian germline stem cell niche is built later during late larval stages and requires a two-step process that involves terminal filament formation and cap cell specification. Intriguingly, double security mechanisms of Notch signaling activation coordinated by the soma or the germline control both steps to ensure the robustness of niche assembly. Second, in the vast domains of mammalian cellular signaling, there is an emerging picture of Notch being an active player in a variety of tissues in health and disease. Notch involvement has been shown in stem cell niche establishment in multiple organs, including the brain, muscle, and intestine, where the stem cell niches are essential for the maintenance of adult stem cells. But adult stem cells are not the only cells looking for a home. Cancer stem cells use Notch signaling at specific stages to gain an advantage over endogenous tissue and overpower it, at the same time acquiring migratory and invasive abilities to claim new tissues (e.g., bone) as their territory. Moreover, in vitro models such as organoids reveal similar Notch employment when it comes to the developing stem cell niches. Therefore, a better understanding of the processes regulating stem cell niche assembly is key for the fields of stem cell biology and regenerative medicines.
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Affiliation(s)
| | | | - Halyna R. Shcherbata
- Mount Desert Island Biological Laboratory, Bar Harbor, ME, United States,*Correspondence: Halyna R. Shcherbata,
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9
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di Pietro F, Herszterg S, Huang A, Bosveld F, Alexandre C, Sancéré L, Pelletier S, Joudat A, Kapoor V, Vincent JP, Bellaïche Y. Rapid and robust optogenetic control of gene expression in Drosophila. Dev Cell 2021; 56:3393-3404.e7. [PMID: 34879263 PMCID: PMC8693864 DOI: 10.1016/j.devcel.2021.11.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 10/13/2021] [Accepted: 11/15/2021] [Indexed: 11/28/2022]
Abstract
Deciphering gene function requires the ability to control gene expression in space and time. Binary systems such as the Gal4/UAS provide a powerful means to modulate gene expression and to induce loss or gain of function. This is best exemplified in Drosophila, where the Gal4/UAS system has been critical to discover conserved mechanisms in development, physiology, neurobiology, and metabolism, to cite a few. Here we describe a transgenic light-inducible Gal4/UAS system (ShineGal4/UAS) based on Magnet photoswitches. We show that it allows efficient, rapid, and robust activation of UAS-driven transgenes in different tissues and at various developmental stages in Drosophila. Furthermore, we illustrate how ShineGal4 enables the generation of gain and loss-of-function phenotypes at animal, organ, and cellular levels. Thanks to the large repertoire of UAS-driven transgenes, ShineGal4 enriches the Drosophila genetic toolkit by allowing in vivo control of gene expression with high temporal and spatial resolutions.
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Affiliation(s)
- Florencia di Pietro
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR 3215, Inserm U934, Genetics and Developmental Biology, 75005 Paris, France
| | | | - Anqi Huang
- Francis Crick Institute, 1 Midland Rd, London NW1 1AT, UK
| | - Floris Bosveld
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR 3215, Inserm U934, Genetics and Developmental Biology, 75005 Paris, France
| | | | - Lucas Sancéré
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR 3215, Inserm U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Stéphane Pelletier
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR 3215, Inserm U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Amina Joudat
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR 3215, Inserm U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Varun Kapoor
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR 3215, Inserm U934, Genetics and Developmental Biology, 75005 Paris, France
| | | | - Yohanns Bellaïche
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR 3215, Inserm U934, Genetics and Developmental Biology, 75005 Paris, France.
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10
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Hounjet J, Vooijs M. The Role of Intracellular Trafficking of Notch Receptors in Ligand-Independent Notch Activation. Biomolecules 2021; 11:biom11091369. [PMID: 34572582 PMCID: PMC8466058 DOI: 10.3390/biom11091369] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/09/2021] [Accepted: 09/10/2021] [Indexed: 12/11/2022] Open
Abstract
Aberrant Notch signaling has been found in a broad range of human malignancies. Consequently, small molecule inhibitors and antibodies targeting Notch signaling in human cancers have been developed and tested; however, these have failed due to limited anti-tumor efficacy because of dose-limiting toxicities in normal tissues. Therefore, there is an unmet need to discover novel regulators of malignant Notch signaling, which do not affect Notch signaling in healthy tissues. This review provides a comprehensive overview of the current knowledge on the role of intracellular trafficking in ligand-independent Notch receptor activation, the possible mechanisms involved, and possible therapeutic opportunities for inhibitors of intracellular trafficking in Notch targeting.
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11
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Bellec K, Pinot M, Gicquel I, Le Borgne R. The Clathrin adaptor AP-1 and Stratum act in parallel pathways to control Notch activation in Drosophila sensory organ precursors cells. Development 2021; 148:dev191437. [PMID: 33298463 PMCID: PMC7823167 DOI: 10.1242/dev.191437] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 11/24/2020] [Indexed: 11/20/2022]
Abstract
Drosophila sensory organ precursors divide asymmetrically to generate pIIa/pIIb cells, the identity of which relies on activation of Notch at cytokinesis. Although Notch is present apically and basally relative to the midbody at the pIIa-pIIb interface, the basal pool of Notch is reported to be the main contributor for Notch activation in the pIIa cell. Intra-lineage signalling requires appropriate apico-basal targeting of Notch, its ligand Delta and its trafficking partner Sanpodo. We have previously reported that AP-1 and Stratum regulate the trafficking of Notch and Sanpodo from the trans-Golgi network to the basolateral membrane. Loss of AP-1 or Stratum caused mild Notch gain-of-function phenotypes. Here, we report that their concomitant loss results in a penetrant Notch gain-of-function phenotype, indicating that they control parallel pathways. Although unequal partitioning of cell fate determinants and cell polarity were unaffected, we observed increased amounts of signalling-competent Notch as well as Delta and Sanpodo at the apical pIIa-pIIb interface, at the expense of the basal pool of Notch. We propose that AP-1 and Stratum operate in parallel pathways to localize Notch and control where receptor activation takes place.
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Affiliation(s)
- Karen Bellec
- Université Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Mathieu Pinot
- Université Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Isabelle Gicquel
- Université Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Roland Le Borgne
- Université Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, F-35000 Rennes, France
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12
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Nandy N, Roy JK. Rab11 is essential for lgl mediated JNK-Dpp signaling in dorsal closure and epithelial morphogenesis in Drosophila. Dev Biol 2020; 464:188-201. [PMID: 32562757 DOI: 10.1016/j.ydbio.2020.06.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 06/11/2020] [Accepted: 06/11/2020] [Indexed: 11/30/2022]
Abstract
Dorsal closure during Drosophila embryogenesis provides a robust genetic platform to study the basic cellular mechanisms that govern epithelial wound healing and morphogenesis. As dorsal closure proceeds, the lateral epithelial tissue (LE) adjacent to the dorsal opening advance contra-laterally, with a simultaneous retraction of the amnioserosa. The process involves a fair degree of coordinated cell shape changes in the dorsal most epithelial (DME) cells as well as a few penultimate rows of lateral epithelial (LE) cells (collectively referred here as Dorsolateral Epithelial (DLE) cells), lining the periphery of the amnioserosa, which in due course of time extend contra-laterally and ultimately fuse over the dorsal hole, giving rise to a dorsal epithelial continuum. The JNK-Dpp signaling in the dorsolateral epidermis, plays an instrumental role in guiding their fate during this process. A large array of genes have been reported to be involved in the regulation of this core signaling pathway, yet the mechanisms by which they do so is hitherto unclear, which forms the objective of our present study. Here we show a probable mechanism via which lgl, a conserved tumour suppressor gene, regulates the JNK-Dpp pathway during dorsal closure and epithelial morphogenesis. A conditional/targeted knock-down of lgl in the dorsolateral epithelium of embryos results in failure of dorsal closure. Interestingly, we also observed a similar phenotype in a Rab11 knockdown condition. Our experiment suggests Rab11 to be interacting with lgl as they seem to synergize in order to regulate the core JNK-Dpp signaling pathway during dorsal closure and also during adult thorax closure process.
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Affiliation(s)
- Nabarun Nandy
- Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, 221005, India
| | - Jagat Kumar Roy
- Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, 221005, India.
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13
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Zhu YX, Li CH, Li G, Feng H, Xia T, Wong CH, Fung FKC, Tong JHM, To KF, Chen R, Chen Y. LLGL1 Regulates Gemcitabine Resistance by Modulating the ERK-SP1-OSMR Pathway in Pancreatic Ductal Adenocarcinoma. Cell Mol Gastroenterol Hepatol 2020; 10:811-828. [PMID: 32615164 PMCID: PMC7505810 DOI: 10.1016/j.jcmgh.2020.06.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 06/22/2020] [Accepted: 06/22/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Gemcitabine resistance is rapidly acquired by pancreatic ductal adenocarcinoma (PDAC) patients. Novel approaches that predict the gemcitabine response of patients and enhance gemcitabine chemosensitivity are important to improve patient survival. We aimed to identify genes as novel biomarkers to predict the gemcitabine response and the therapeutic targets to attenuate chemoresistance in PDAC cells. METHODS Genome-wide RNA interference screening was conducted to identify genes that regulated gemcitabine chemoresistance. A cell proliferation assay and a tumor formation assay were conducted to study the role of lethal giant larvae homolog 1 (LLGL1) in gemcitabine chemoresistance. Levels of LLGL1 and its regulating targets were measured by immunohistochemical staining in tumor tissues obtained from patients who received gemcitabine as a single therapeutic agent. A gene-expression microarray was conducted to identify the targets regulated by LLGL1. RESULTS Silencing of LLGL1 markedly reduced the gemcitabine chemosensitivity in PDAC cells. Patients had significantly shorter survival (6 months) if they bore tumors expressing low LLGL1 level than tumors with high LLGL1 level (20 months) (hazard ratio, 0.1567; 95% CI, 0.05966-0.4117). Loss of LLGL1 promoted cytokine receptor oncostatin M receptor (OSMR) expression in PDAC cells that led to gemcitabine resistance, while knockdown of OSMR effectively rescued the chemoresistance phenotype. The LLGL1-OSMR regulatory pathway showed great clinical importance because low LLGL1 and high OSMR expressions were observed frequently in PDAC tissues. Silencing of LLGL1 induced phosphorylation of extracellular signal-regulated kinase 2 and specificity protein 1 (Sp1), promoted Sp1 (pThr453) binding at the OSMR promoter, and enhanced OSMR transcription. CONCLUSIONS LLGL1 possessed a tumor-suppressor role as an inhibitor of chemoresistance by regulating OSMR-extracellular signal-regulated kinase 2/Sp1 signaling. The data sets generated and analyzed during the current study are available in the Gene Expression Omnibus repository (ID: GSE64681).
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Affiliation(s)
- Yin-Xin Zhu
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Chi Han Li
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Guolin Li
- Department of Hepatobiliary Surgery, Sun Yat-sen Memorial Hospital, Guangzhou, China
| | - Huiyi Feng
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Tian Xia
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Chi Hin Wong
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Frederic Khe Cheong Fung
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Joanna Hung-Man Tong
- Department of Anatomical and Cellular Pathology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Ka-Fai To
- Department of Anatomical and Cellular Pathology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Rufu Chen
- Guangdong Provincial People's Hospital, Guangzhou, Guangdong Province, China.
| | - Yangchao Chen
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong; Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, China.
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14
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Thevenon D, Seffouh I, Pillet C, Crespo-Yanez X, Fauvarque MO, Taillebourg E. A Nucleolar Isoform of the Drosophila Ubiquitin Specific Protease dUSP36 Regulates MYC-Dependent Cell Growth. Front Cell Dev Biol 2020; 8:506. [PMID: 32637412 PMCID: PMC7316882 DOI: 10.3389/fcell.2020.00506] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 05/27/2020] [Indexed: 12/13/2022] Open
Abstract
The c-Myc oncogene is a transcription factor that regulates the expression of a very large set of genes mainly involved in cell growth and proliferation. It is overexpressed in more than 70% of human cancers, illustrating the importance of keeping its levels and activity under control. The ubiquitin proteasome system is a major regulator of MYC levels in humans as well as in model organisms such as Drosophila melanogaster. Although the E3 ligases that promote MYC ubiquitination have been largely investigated, the identity and the role of the deubiquitinating enzymes, which counteract their action is only beginning to be unraveled. Using isoform-specific CRISPR-Cas9 mutagenesis, we show that the Drosophila homolog of the Ubiquitin Specific Protease USP36 has different isoforms with specific sub-cellular localizations and that the nucleolar dUSP36-D isoform is specifically required for cell and organismal growth. We also demonstrate that this isoform interacts with dMYC and the E3 ligase AGO and regulates their stability and ubiquitination levels. Furthermore, we show that dUSP36 is ubiquitinated by AGO and is able to self-deubiquitinate. Finally, we provide in vivo evidence supporting the functional relevance of these regulatory relationships. Together these results reveal that dMYC, AGO and dUSP36 form a tripartite, evolutionary conserved complex that acts as a regulatory node to control dMYC protein levels.
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15
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Miszczak K, Egger B. Live Cell Imaging of Neural Stem Cells in the Drosophila Larval Brain. Methods Mol Biol 2020; 2047:153-160. [PMID: 31552654 DOI: 10.1007/978-1-4939-9732-9_9] [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] [Indexed: 01/19/2023]
Abstract
Live cell imaging gives valuable insights into the dynamic biological processes within and between cells. An important aspect of live cell imaging is to keep the cells under best physiological condition and to prevent abnormal cellular behavior, which might be caused by phototoxicity during microscopy. In this chapter we describe a protocol to visualize division patterns of neural stem cells in live whole mount brains of Drosophila larvae. We also present a newly developed live cell chamber that allows us to control the environmental air during live cell imaging. The protocol can be adapted to look at a wide range of cellular and tissue behavior in the Drosophila model system.
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Affiliation(s)
- Karolina Miszczak
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Boris Egger
- Department of Biology, University of Fribourg, Fribourg, Switzerland.
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16
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Domingos PM, Jenny A, Combie KF, Del Alamo D, Mlodzik M, Steller H, Mollereau B. Regulation of Numb during planar cell polarity establishment in the Drosophila eye. Mech Dev 2019; 160:103583. [PMID: 31678471 DOI: 10.1016/j.mod.2019.103583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 10/17/2019] [Accepted: 10/29/2019] [Indexed: 01/15/2023]
Abstract
The establishment of planar cell polarity (PCP) in the Drosophila eye requires correct specification of the R3/R4 pair of photoreceptor cells, determined by a Frizzled mediated signaling event that specifies R3 and induces Delta to activate Notch signaling in the neighboring cell, specifying it as R4. Here, we investigated the role of the Notch signaling negative regulator Numb in the specification of R3/R4 fates and PCP establishment in the Drosophila eye. We observed that Numb is transiently upregulated in R3 at the time of R3/R4 specification. This regulation of Numb levels in developing photoreceptors occurs at the post-transcriptional level and is dependent on Dishevelled, an effector of Frizzled signaling, and Lethal Giant Larva. We detected PCP defects in cells homozygous for numb15, but these defects were due to a loss of function mutation in fat (fatQ805⁎) being present in the numb15 chromosome. However, mosaic overexpression of Numb in R4 precursors (only) caused PCP defects and numb loss-of-function alleles had a modifying effect on the defects found in a hypomorphic dishevelled mutation. Our results suggest that Numb levels are upregulated to reinforce the bias of Notch signaling activation in the R3/R4 pair, two post-mitotic cells that are not specified by asymmetric cell division.
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Affiliation(s)
- Pedro M Domingos
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, Oeiras 2780-157, Portugal; Strang Laboratory of Apoptosis and Cancer Research, The Rockefeller University, Box 252, 1230 York Avenue, New York, NY 10065, USA.
| | - Andreas Jenny
- Albert Einstein College of Medicine, 1300 Morris Park Avenue, Chanin Building, Room 503, Bronx NY10461, USA; Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA
| | - Keon F Combie
- Strang Laboratory of Apoptosis and Cancer Research, The Rockefeller University, Box 252, 1230 York Avenue, New York, NY 10065, USA
| | - David Del Alamo
- Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA; European Molecular Biology Organization, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Marek Mlodzik
- Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA
| | - Hermann Steller
- Strang Laboratory of Apoptosis and Cancer Research, The Rockefeller University, Box 252, 1230 York Avenue, New York, NY 10065, USA
| | - Bertrand Mollereau
- Strang Laboratory of Apoptosis and Cancer Research, The Rockefeller University, Box 252, 1230 York Avenue, New York, NY 10065, USA; Université de Lyon, ENSL, UCBL, CNRS, LBMC, 46 Allée d'Italie, 69007 Lyon, France.
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17
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A genetic mosaic screen identifies genes modulating Notch signaling in Drosophila. PLoS One 2018; 13:e0203781. [PMID: 30235233 PMCID: PMC6147428 DOI: 10.1371/journal.pone.0203781] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 08/27/2018] [Indexed: 01/08/2023] Open
Abstract
Notch signaling is conserved in most multicellular organisms and plays critical roles during animal development. The core components and major signal transduction mechanism of Notch signaling have been extensively studied. However, our understanding of how Notch signaling activity is regulated in diverse developmental processes still remains incomplete. Here, we report a genetic mosaic screen in Drosophila melanogaster that leads to identification of Notch signali ng modulators during wing development. We discovered a group of genes required for the formation of the fly wing margin, a developmental process that is strictly dependent on the balanced Notch signaling activity. These genes encode transcription factors, protein phosphatases, vacuolar ATPases and factors required for RNA transport, stability, and translation. Our data support the view that Notch signaling is controlled through a wide range of molecular processes. These results also provide foundations for further study by showing that Me31B and Wdr62 function as two novel modulators of Notch signaling activity.
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18
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Bellec K, Gicquel I, Le Borgne R. Stratum recruits Rab8 at Golgi exit sites to regulate the basolateral sorting of Notch and Sanpodo. Development 2018; 145:145/13/dev163469. [PMID: 29967125 DOI: 10.1242/dev.163469] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 05/21/2018] [Indexed: 01/03/2023]
Abstract
In Drosophila, the sensory organ precursor (SOP or pI cell) divides asymmetrically to give birth to daughter cells, the fates of which are governed by the differential activation of the Notch pathway. Proteolytic activation of Notch induced by ligand is based on the correct polarized sorting and localization of the Notch ligand Delta, the Notch receptor and its trafficking partner Sanpodo (Spdo). Here, we have identified Stratum (Strat), a presumptive guanine nucleotide exchange factor for Rab GTPases, as a regulator of Notch activation. Loss of Strat causes cell fate transformations associated with an accumulation of Notch, Delta and Spdo in the trans-Golgi network (TGN), and an apical accumulation of Spdo. The strat mutant phenotype is rescued by the catalytically active as well as the wild-type form of Rab8, suggesting a chaperone function for Strat rather than that of exchange factor. Strat is required to localize Rab8 at the TGN, and rab8 phenocopies strat We propose that Strat and Rab8 act at the exit of the Golgi apparatus to regulate the sorting and the polarized distribution of Notch, Delta and Spdo.
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Affiliation(s)
- Karen Bellec
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Isabelle Gicquel
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, F-35000 Rennes, France
| | - Roland Le Borgne
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, F-35000 Rennes, France
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19
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dSTIM- and Ral/Exocyst-Mediated Synaptic Release from Pupal Dopaminergic Neurons Sustains Drosophila Flight. eNeuro 2018; 5:eN-NWR-0455-17. [PMID: 29938216 PMCID: PMC6011419 DOI: 10.1523/eneuro.0455-17.2018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 05/06/2018] [Accepted: 05/07/2018] [Indexed: 12/13/2022] Open
Abstract
Manifestation of appropriate behavior in adult animals requires developmental mechanisms that help in the formation of correctly wired neural circuits. Flight circuit development in Drosophila requires store-operated calcium entry (SOCE) through the STIM/Orai pathway. SOCE-associated flight deficits in adult Drosophila derive extensively from regulation of gene expression in pupal neurons, and one such SOCE-regulated gene encodes the small GTPase Ral. The cellular mechanism by which Ral helps in maturation of the flight circuit was not understood. Here, we show that knockdown of components of a Ral effector, the exocyst complex, in pupal neurons also leads to reduced flight bout durations, and this phenotype derives primarily from dopaminergic neurons. Importantly, synaptic release from pupal dopaminergic neurons is abrogated upon knockdown of dSTIM, Ral, or exocyst components. Ral overexpression restores the diminished synaptic release of dStim knockdown neurons as well as flight deficits associated with dSTIM knockdown in dopaminergic neurons. These results identify Ral-mediated vesicular release as an effector mechanism of neuronal SOCE in pupal dopaminergic neurons with functional consequences on flight behavior.
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20
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Salazar JL, Yamamoto S. Integration of Drosophila and Human Genetics to Understand Notch Signaling Related Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1066:141-185. [PMID: 30030826 PMCID: PMC6233323 DOI: 10.1007/978-3-319-89512-3_8] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Notch signaling research dates back to more than one hundred years, beginning with the identification of the Notch mutant in the fruit fly Drosophila melanogaster. Since then, research on Notch and related genes in flies has laid the foundation of what we now know as the Notch signaling pathway. In the 1990s, basic biological and biochemical studies of Notch signaling components in mammalian systems, as well as identification of rare mutations in Notch signaling pathway genes in human patients with rare Mendelian diseases or cancer, increased the significance of this pathway in human biology and medicine. In the 21st century, Drosophila and other genetic model organisms continue to play a leading role in understanding basic Notch biology. Furthermore, these model organisms can be used in a translational manner to study underlying mechanisms of Notch-related human diseases and to investigate the function of novel disease associated genes and variants. In this chapter, we first briefly review the major contributions of Drosophila to Notch signaling research, discussing the similarities and differences between the fly and human pathways. Next, we introduce several biological contexts in Drosophila in which Notch signaling has been extensively characterized. Finally, we discuss a number of genetic diseases caused by mutations in genes in the Notch signaling pathway in humans and we expand on how Drosophila can be used to study rare genetic variants associated with these and novel disorders. By combining modern genomics and state-of-the art technologies, Drosophila research is continuing to reveal exciting biology that sheds light onto mechanisms of disease.
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Affiliation(s)
- Jose L Salazar
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, TX, USA
| | - Shinya Yamamoto
- Department of Molecular and Human Genetics, Baylor College of Medicine (BCM), Houston, TX, USA.
- Program in Developmental Biology, BCM, Houston, TX, USA.
- Department of Neuroscience, BCM, Houston, TX, USA.
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA.
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21
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Milgrom-Hoffman M, Humbert PO. Regulation of cellular and PCP signalling by the Scribble polarity module. Semin Cell Dev Biol 2017; 81:33-45. [PMID: 29154823 DOI: 10.1016/j.semcdb.2017.11.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Revised: 11/11/2017] [Accepted: 11/13/2017] [Indexed: 10/18/2022]
Abstract
Since the first identification of the Scribble polarity module proteins as a new class of tumour suppressors that regulate both cell polarity and proliferation, an increasing amount of evidence has uncovered a broader role for Scribble, Dlg and Lgl in the control of fundamental cellular functions and their signalling pathways. Here, we review these findings as well as discuss more specifically the role of the Scribble module in PCP signalling.
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Affiliation(s)
- Michal Milgrom-Hoffman
- Department of Biochemistry & Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Patrick O Humbert
- Department of Biochemistry & Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia; Department of Biochemistry & Molecular Biology, University of Melbourne, Melbourne, Victoria 3010, Australia; Department of Pathology, University of Melbourne, Melbourne, Victoria 3010, Australia.
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22
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Sallé J, Gervais L, Boumard B, Stefanutti M, Siudeja K, Bardin AJ. Intrinsic regulation of enteroendocrine fate by Numb. EMBO J 2017; 36:1928-1945. [PMID: 28533229 DOI: 10.15252/embj.201695622] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 04/10/2017] [Accepted: 04/11/2017] [Indexed: 12/25/2022] Open
Abstract
How terminal cell fates are specified in dynamically renewing adult tissues is not well understood. Here we explore terminal cell fate establishment during homeostasis using the enteroendocrine cells (EEs) of the adult Drosophila midgut as a paradigm. Our data argue against the existence of local feedback signals, and we identify Numb as an intrinsic regulator of EE fate. Our data further indicate that Numb, with alpha-adaptin, acts upstream or in parallel of known regulators of EE fate to limit Notch signaling, thereby facilitating EE fate acquisition. We find that Numb is regulated in part through its asymmetric and symmetric distribution during stem cell divisions; however, its de novo synthesis is also required during the differentiation of the EE cell. Thus, this work identifies Numb as a crucial factor for cell fate choice in the adult Drosophila intestine. Furthermore, our findings demonstrate that cell-intrinsic control mechanisms of terminal cell fate acquisition can result in a balanced tissue-wide production of terminally differentiated cell types.
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Affiliation(s)
- Jérémy Sallé
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Stem Cells and Tissue Homeostasis Group, Paris, France.,Sorbonne Universités, UPMC Univ Paris 6, Paris, France
| | - Louis Gervais
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Stem Cells and Tissue Homeostasis Group, Paris, France.,Sorbonne Universités, UPMC Univ Paris 6, Paris, France
| | - Benjamin Boumard
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Stem Cells and Tissue Homeostasis Group, Paris, France.,Sorbonne Universités, UPMC Univ Paris 6, Paris, France.,Département de Biologie, École Normale Supérieure de Lyon, Lyon, France
| | - Marine Stefanutti
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Stem Cells and Tissue Homeostasis Group, Paris, France.,Sorbonne Universités, UPMC Univ Paris 6, Paris, France
| | - Katarzyna Siudeja
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Stem Cells and Tissue Homeostasis Group, Paris, France.,Sorbonne Universités, UPMC Univ Paris 6, Paris, France
| | - Allison J Bardin
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, Stem Cells and Tissue Homeostasis Group, Paris, France .,Sorbonne Universités, UPMC Univ Paris 6, Paris, France
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23
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Long Term Ex Vivo Culture and Live Imaging of Drosophila Larval Imaginal Discs. PLoS One 2016; 11:e0163744. [PMID: 27685172 PMCID: PMC5042436 DOI: 10.1371/journal.pone.0163744] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 09/13/2016] [Indexed: 12/27/2022] Open
Abstract
Continuous imaging of live tissues provides clear temporal sequence of biological events. The Drosophila imaginal discs have been popular experimental subjects for the study of a wide variety of biological phenomena, but long term culture that allows normal development has not been satisfactory. Here we report a culture method that can sustain normal development for 18 hours and allows live imaging. The method is validated in multiple discs and for cell proliferation, differentiation and migration. However, it does not support disc growth and cannot support cell proliferation for more than 7 to 12 hr. We monitored the cellular behavior of retinal basal glia in the developing eye disc and found that distinct glia type has distinct properties of proliferation and migration. The live imaging provided direct proof that wrapping glia differentiated from existing glia after migrating to the anterior front, and unexpectedly found that they undergo endoreplication before wrapping axons, and their nuclei migrate up and down along the axons. UV-induced specific labeling of a single carpet glia also showed that the two carpet glia membrane do not overlap and suggests a tiling or repulsion mechanism between the two cells. These findings demonstrated the usefulness of an ex vivo culture method and live imaging.
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24
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Johnson SA, Zitserman D, Roegiers F. Numb regulates the balance between Notch recycling and late-endosome targeting in Drosophila neural progenitor cells. Mol Biol Cell 2016; 27:2857-66. [PMID: 27466320 PMCID: PMC5025272 DOI: 10.1091/mbc.e15-11-0751] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 07/21/2016] [Indexed: 11/11/2022] Open
Abstract
Steady-state and pulse-labeling techniques are used to follow Notch receptors in sensory organ precursor cells in Drosophila. Numb and L(2)gl antagonize a pool of Notch receptors, and Numb promotes Notch targeting to late endosomes in Drosophila neural progenitors to regulate Notch signaling and cell fate. The Notch signaling pathway plays essential roles in both animal development and human disease. Regulation of Notch receptor levels in membrane compartments has been shown to affect signaling in a variety of contexts. Here we used steady-state and pulse-labeling techniques to follow Notch receptors in sensory organ precursor cells in Drosophila. We find that the endosomal adaptor protein Numb regulates levels of Notch receptor trafficking to Rab7-labeled late endosomes but not early endosomes. Using an assay we developed that labels different pools of Notch receptors as they move through the endocytic system, we show that Numb specifically suppresses a recycled Notch receptor subpopulation and that excess Notch signaling in numb mutants requires the recycling endosome GTPase Rab11 activity. Our data therefore suggest that Numb controls the balance between Notch receptor recycling and receptor targeting to late endosomes to regulate signaling output after asymmetric cell division in Drosophila neural progenitors.
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Affiliation(s)
- Seth A Johnson
- Fox Chase Cancer Center, Philadelphia, PA 19111 Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Diana Zitserman
- Fox Chase Cancer Center, Philadelphia, PA 19111 University of Bridgeport, Bridgeport, CT 06604
| | - Fabrice Roegiers
- Fox Chase Cancer Center, Philadelphia, PA 19111 Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
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25
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Portela M, Parsons LM, Grzeschik NA, Richardson HE. Regulation of Notch signaling and endocytosis by the Lgl neoplastic tumor suppressor. Cell Cycle 2016; 14:1496-506. [PMID: 25789785 DOI: 10.1080/15384101.2015.1026515] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The evolutionarily conserved neoplastic tumor suppressor protein, Lethal (2) giant larvae (Lgl), plays roles in cell polarity and tissue growth via regulation of the Hippo pathway. In our recent study, we showed that in the developing Drosophila eye epithelium, depletion of Lgl leads to increased ligand-dependent Notch signaling. lgl mutant tissue also exhibits an accumulation of early endosomes, recycling endosomes, early-multivesicular body markers and acidic vesicles. We showed that elevated Notch signaling in lgl(-) tissue can be rescued by feeding larvae the vesicle de-acidifying drug chloroquine, revealing that Lgl attenuates Notch signaling by limiting vesicle acidification. Strikingly, chloroquine also rescued the lgl(-) overgrowth phenotype, suggesting that the Hippo pathway defects were also rescued. In this extraview, we provide additional data on the regulation of Notch signaling and endocytosis by Lgl, and discuss possible mechanisms by which Lgl depletion contributes to signaling pathway defects and tumorigenesis.
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Affiliation(s)
- Marta Portela
- a Cell Cycle and Development Laboratory; Research Division ; Peter MacCallum Cancer Centre ; Melbourne , Victoria , Australia
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26
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Store-Operated Calcium Entry through Orai Is Required for Transcriptional Maturation of the Flight Circuit in Drosophila. J Neurosci 2016; 35:13784-99. [PMID: 26446229 DOI: 10.1523/jneurosci.1680-15.2015] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
UNLABELLED Store operated calcium entry (SOCE) is thought to primarily regulate calcium homeostasis in neurons. Subsequent to identification of Orai as the SOCE channel in nonexcitable cells, investigation of Orai function in neurons demonstrated a requirement for SOCE in Drosophila flight. Here, by analysis of an Orai mutant and by controlled expression of a dominant-negative Drosophila Orai transgene, we show that Orai-mediated SOCE is required in dopaminergic interneurons of the flight circuit during pupal development. Expression of dominant-negative Orai in dopaminergic neurons of pupae abolished flight. The loss of Orai-mediated SOCE alters transcriptional regulation of dopaminergic neurons, leading to downregulation of the enzyme tyrosine hydroxylase, which is essential for dopamine synthesis, and the dopamine transporter, which is required for dopamine uptake after synaptic release. These studies suggest that modulation of SOCE could serve as a novel mechanism for restoring dopamine levels in dopaminergic neurons. SIGNIFICANCE STATEMENT The specificity of an animal's response to an environmental stimulus is determined in part by the release of neurotransmitters, which are sensed by responding neurons through cognate receptors on their surface. One way by which neurons respond is through release of calcium from intracellular stores followed by store refilling from extracellular calcium sources. This mechanism is called store-operated calcium entry (SOCE). The function of SOCE in neurons has been debated. Here we describe a new function for SOCE in the regulation of neurotransmitter levels in Drosophila flight neurons. This cell-signaling mechanism is required to maintain optimal levels of a key enzyme for dopamine synthesis and may serve as a mechanism for restoring dopamine levels in relevant pathological conditions.
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27
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Reiff T, Jacobson J, Cognigni P, Antonello Z, Ballesta E, Tan KJ, Yew JY, Dominguez M, Miguel-Aliaga I. Endocrine remodelling of the adult intestine sustains reproduction in Drosophila. eLife 2015. [PMID: 26216039 PMCID: PMC4515472 DOI: 10.7554/elife.06930] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The production of offspring is energetically costly and relies on incompletely understood mechanisms that generate a positive energy balance. In mothers of many species, changes in key energy-associated internal organs are common yet poorly characterised functionally and mechanistically. In this study, we show that, in adult Drosophila females, the midgut is dramatically remodelled to enhance reproductive output. In contrast to extant models, organ remodelling does not occur in response to increased nutrient intake and/or offspring demands, but rather precedes them. With spatially and temporally directed manipulations, we identify juvenile hormone (JH) as an anticipatory endocrine signal released after mating. Acting through intestinal bHLH-PAS domain proteins Methoprene-tolerant (Met) and Germ cell-expressed (Gce), JH signals directly to intestinal progenitors to yield a larger organ, and adjusts gene expression and sterol regulatory element-binding protein (SREBP) activity in enterocytes to support increased lipid metabolism. Our findings identify a metabolically significant paradigm of adult somatic organ remodelling linking hormonal signals, epithelial plasticity, and reproductive output.
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Affiliation(s)
- Tobias Reiff
- Instituto de Neurociencias, Consejo Superior de Investigaciones Cientificas, Universidad Miguel Hernández, Alicante, Spain
| | - Jake Jacobson
- MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom
| | - Paola Cognigni
- MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom
| | - Zeus Antonello
- Instituto de Neurociencias, Consejo Superior de Investigaciones Cientificas, Universidad Miguel Hernández, Alicante, Spain
| | - Esther Ballesta
- Instituto de Neurociencias, Consejo Superior de Investigaciones Cientificas, Universidad Miguel Hernández, Alicante, Spain
| | - Kah Junn Tan
- Temasek Life Sciences Laboratory, Singapore, Singapore
| | - Joanne Y Yew
- Temasek Life Sciences Laboratory, Singapore, Singapore
| | - Maria Dominguez
- Instituto de Neurociencias, Consejo Superior de Investigaciones Cientificas, Universidad Miguel Hernández, Alicante, Spain
| | - Irene Miguel-Aliaga
- MRC Clinical Sciences Centre, Imperial College London, London, United Kingdom
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Lee YM, Sun YH. Maintenance of glia in the optic lamina is mediated by EGFR signaling by photoreceptors in adult Drosophila. PLoS Genet 2015; 11:e1005187. [PMID: 25909451 PMCID: PMC4409299 DOI: 10.1371/journal.pgen.1005187] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 03/31/2015] [Indexed: 01/13/2023] Open
Abstract
The late onset of neurodegeneration in humans indicates that the survival and function of cells in the nervous system must be maintained throughout adulthood. In the optic lamina of the adult Drosophila, the photoreceptor axons are surrounded by multiple types of glia. We demonstrated that the adult photoreceptors actively contribute to glia maintenance in their target field within the optic lamina. This effect is dependent on the epidermal growth factor receptor (EGFR) ligands produced by the R1-6 photoreceptors and transported to the optic lamina to act on EGFR in the lamina glia. EGFR signaling is necessary and sufficient to act in a cell-autonomous manner in the lamina glia. Our results suggest that EGFR signaling is required for the trafficking of the autophagosome/endosome to the lysosome. The loss of EGFR signaling results in cell degeneration most likely because of the accumulation of autophagosomes. Our findings provide in vivo evidence for the role of adult neurons in the maintenance of glia and a novel role for EGFR signaling in the autophagic flux. Degeneration of the nervous system can be viewed as a failure to maintain cell survival or function in the nervous system. The late onset of neurodegeneration in humans indicates that the cell survival in the nervous system must be maintained throughout our lives. Neuronal survival is maintained by neurotrophic factors in adults; however, it is unclear whether glia survival is also maintained throughout adulthood. Here, we use the Drosophila visual system as a model to address the role played by adult neurons for the active maintenance of glia. We demonstrated that the adult photoreceptors secrete a signaling molecule, which is transported to the brain to act on the lamina glia and maintain its integrity. When this signaling pathway is blocked, the lamina glia undergoes a progressive and irreversible degeneration. The primary defect occurs in the trafficking from the late endosome and autophagosome to the lysosome. This defect leads to an accumulation of autophagosomes and subsequent cell degeneration as a result of autophagy. Our findings provide in vivo evidence for a novel aspect of the neuron-glia interaction and a novel role for EGFR signaling in regulating the maintenance and degeneration of the nervous system.
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Affiliation(s)
- Yuan-Ming Lee
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- Institute of Genomic Sciences, National Yang-Ming University, Taipei, Taiwan
| | - Y. Henry Sun
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
- Institute of Genomic Sciences, National Yang-Ming University, Taipei, Taiwan
- * E-mail:
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Cao F, Miao Y, Xu K, Liu P. Lethal (2) giant larvae: an indispensable regulator of cell polarity and cancer development. Int J Biol Sci 2015; 11:380-9. [PMID: 25798058 PMCID: PMC4366637 DOI: 10.7150/ijbs.11243] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 01/21/2015] [Indexed: 01/04/2023] Open
Abstract
Cell polarity is one of the most basic properties of all normal cells and is essential for regulating numerous biological processes. Loss of polarity is considered a hallmark for cancer. Multiple polarity proteins are implicated in maintenance of cell polarity. Lethal (2) giant larvae (Lgl) is one of polarity proteins that plays an important role in regulating cell polarity, asymmetric division as well as tumorigenesis. Lgl proteins in different species have similar structures and conserved functions. Lgl acts as an indispensable regulator of cell biological function, including cell polarity and asymmetric division, through interplaying with other polarity proteins, regulating exocytosis, mediating cytoskeleton and being involved in signaling pathways. Furthermore, Lgl plays a role of a tumor suppressor, and the aberrant expression of Hugl, a human homologue of Lgl, contributes to multiple cancers. However, the exact functions of Lgl and the underlying mechanisms remain enigmatic. In this review, we will give an overview of the Lgl functions in cell polarity and cancer development, discuss the potential mechanisms underlying these functions, and raise our conclusion of previous studies and points of view about the future studies.
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Affiliation(s)
- Fang Cao
- 1. Center for Translational Medicine, The First Affiliated Hospital of Xian Jiaotong University, College of Medicine, Xi'an, China
| | - Yi Miao
- 1. Center for Translational Medicine, The First Affiliated Hospital of Xian Jiaotong University, College of Medicine, Xi'an, China
| | - Kedong Xu
- 2. Department of Hepatobiliary Surgery, The First Affiliated Hospital of Xian Jiaotong University, College of Medicine, Xi'an, China
| | - Peijun Liu
- 1. Center for Translational Medicine, The First Affiliated Hospital of Xian Jiaotong University, College of Medicine, Xi'an, China
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30
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Couturier L, Trylinski M, Mazouni K, Darnet L, Schweisguth F. A fluorescent tagging approach in Drosophila reveals late endosomal trafficking of Notch and Sanpodo. ACTA ACUST UNITED AC 2014; 207:351-63. [PMID: 25365996 PMCID: PMC4226730 DOI: 10.1083/jcb.201407071] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Signaling and endocytosis are highly integrated processes that regulate cell fate. In the Drosophila melanogaster sensory bristle lineages, Numb inhibits the recycling of Notch and its trafficking partner Sanpodo (Spdo) to regulate cell fate after asymmetric cell division. In this paper, we have used a dual GFP/Cherry tagging approach to study the distribution and endosomal sorting of Notch and Spdo in living pupae. The specific properties of GFP, i.e., quenching at low pH, and Cherry, i.e., slow maturation time, revealed distinct pools of Notch and Spdo: cargoes exhibiting high GFP/low Cherry fluorescence intensities localized mostly at the plasma membrane and early/sorting endosomes, whereas low GFP/high Cherry cargoes accumulated in late acidic endosomes. These properties were used to show that Spdo is sorted toward late endosomes in a Numb-dependent manner. This dual-tagging approach should be generally applicable to study the trafficking dynamics of membrane proteins in living cells and tissues.
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Affiliation(s)
- Lydie Couturier
- Developmental and Stem Cell Biology Department, Institut Pasteur, 75015 Paris, France Centre National de la Recherche Scientifique, URA2578, 75015 Paris, France
| | - Mateusz Trylinski
- Developmental and Stem Cell Biology Department, Institut Pasteur, 75015 Paris, France Centre National de la Recherche Scientifique, URA2578, 75015 Paris, France Master Biosciences, École Normale Supérieure de Lyon, 75015 Paris, France
| | - Khallil Mazouni
- Developmental and Stem Cell Biology Department, Institut Pasteur, 75015 Paris, France Centre National de la Recherche Scientifique, URA2578, 75015 Paris, France
| | - Léa Darnet
- Developmental and Stem Cell Biology Department, Institut Pasteur, 75015 Paris, France Centre National de la Recherche Scientifique, URA2578, 75015 Paris, France
| | - François Schweisguth
- Developmental and Stem Cell Biology Department, Institut Pasteur, 75015 Paris, France Centre National de la Recherche Scientifique, URA2578, 75015 Paris, France
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Yashiro H, Loza AJ, Skeath JB, Longmore GD. Rho1 regulates adherens junction remodeling by promoting recycling endosome formation through activation of myosin II. Mol Biol Cell 2014; 25:2956-69. [PMID: 25079692 PMCID: PMC4230585 DOI: 10.1091/mbc.e14-04-0894] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Once adherens junctions (AJs) are formed between polarized epithelial cells they must be maintained because AJs are constantly remodeled in dynamic epithelia. AJ maintenance involves endocytosis and subsequent recycling of E-cadherin to a precise location along the basolateral membrane. In the Drosophila pupal eye epithelium, Rho1 GTPase regulates AJ remodeling through Drosophila E-cadherin (DE-cadherin) endocytosis by limiting Cdc42/Par6/aPKC complex activity. We demonstrate that Rho1 also influences AJ remodeling by regulating the formation of DE-cadherin-containing, Rab11-positive recycling endosomes in Drosophila postmitotic pupal eye epithelia. This effect of Rho1 is mediated through Rok-dependent, but not MLCK-dependent, stimulation of myosin II activity yet independent of its effects upon actin remodeling. Both Rho1 and pMLC localize on endosomal vesicles, suggesting that Rho1 might regulate the formation of recycling endosomes through localized myosin II activation. This work identifies spatially distinct functions for Rho1 in the regulation of DE-cadherin-containing vesicular trafficking during AJ remodeling in live epithelia.
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Affiliation(s)
- Hanako Yashiro
- ICCE Institute, Washington University School of Medicine, St. Louis, MO 63110 Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110 Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110
| | - Andrew J Loza
- ICCE Institute, Washington University School of Medicine, St. Louis, MO 63110 Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110
| | - James B Skeath
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110
| | - Gregory D Longmore
- ICCE Institute, Washington University School of Medicine, St. Louis, MO 63110 Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110 Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110 BRIGHT Institute, Washington University School of Medicine, St. Louis, MO 63110
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32
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Goh LH, Zhou X, Lee MC, Lin S, Wang H, Luo Y, Yang X. Clueless regulates aPKC activity and promotes self-renewal cell fate in Drosophila lgl mutant larval brains. Dev Biol 2013; 381:353-64. [PMID: 23835532 DOI: 10.1016/j.ydbio.2013.06.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 06/13/2013] [Accepted: 06/30/2013] [Indexed: 11/16/2022]
Abstract
Asymmetric cell division of Drosophila neural stem cells or neuroblasts is an important process which gives rise to two different daughter cells, one of which is the stem cell itself and the other, a committed or differentiated daughter cell. During neuroblast asymmetric division, atypical Protein Kinase C (aPKC) activity is tightly regulated; aberrant levels of activity could result in tumorigenesis in third instar larval brain. We identified clueless (clu), a genetic interactor of parkin (park), as a novel regulator of aPKC activity. It preferentially binds to the aPKC/Bazooka/Partition Defective 6 complex and stabilizes aPKC levels. In clu mutants, Miranda (Mira) and Numb are mislocalized in small percentages of dividing neuroblasts. Adult mutants are short-lived with severe locomotion defects. Clu promotes tumorigenesis caused by loss of function of lethal(2) giant larvae (lgl) in the larval brain. Removal of clu in lgl mutants rescues Mira and Numb mislocalization and restores the enlarged brain size. Western blot analyses indicate that the rescue is due to the down-regulation of aPKC levels in the lgl clu double mutant. Interestingly, the phenotype of the park mutant, which causes Parkinson's Disease-like symptoms in adult flies, is reminiscent of that of clu in neuroblast asymmetric division. Our study provides the first clue for the potential missing pathological link between temporally separated neurogenesis and neurodegeneration events; the minor defects during early neurogenesis could be a susceptible factor contributing to neurodegenerative diseases at later stages of life.
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Affiliation(s)
- Li Hui Goh
- Institute of Molecular and Cell Biology, Singapore
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Jauffred B, Llense F, Sommer B, Wang Z, Martin C, Bellaiche Y. Regulation of centrosome movements by Numb and the Collapsin Response Mediator Protein during Drosophila sensory progenitor asymmetric division. Development 2013; 140:2657-68. [DOI: 10.1242/dev.087338] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Asymmetric cell division generates cell fate diversity during development and adult life. Recent findings have demonstrated that during stem cell divisions, the movement of centrosomes is asymmetric in prophase and that such asymmetry participates in mitotic spindle orientation and cell polarization. Here, we have investigated the dynamics of centrosomes during Drosophila sensory organ precursor asymmetric divisions and find that centrosome movements are asymmetric during cytokinesis. We demonstrate that centrosome movements are controlled by the cell fate determinant Numb, which does not act via its classical effectors, Sanpodo and α-Adaptin, but via the Collapsin Response Mediator Protein (CRMP). Furthermore, we find that CRMP is necessary for efficient Notch signalling and that it regulates the duration of the pericentriolar accumulation of Rab11-positive endosomes, through which the Notch ligand, Delta is recycled. Our work characterizes an additional mode of asymmetric centrosome movement during asymmetric divisions and suggests a model whereby the asymmetry in centrosome movements participates in differential Notch activation to regulate cell fate specification.
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Affiliation(s)
- Bertrand Jauffred
- Polarity, Division and Morphogenesis Team, Institut Curie, CNRS UMR 3215, INSERM U934, 26 rue d’Ulm, 75248 Paris Cedex 05, France
| | - Flora Llense
- Polarity, Division and Morphogenesis Team, Institut Curie, CNRS UMR 3215, INSERM U934, 26 rue d’Ulm, 75248 Paris Cedex 05, France
| | - Bernhard Sommer
- Polarity, Division and Morphogenesis Team, Institut Curie, CNRS UMR 3215, INSERM U934, 26 rue d’Ulm, 75248 Paris Cedex 05, France
| | - Zhimin Wang
- Polarity, Division and Morphogenesis Team, Institut Curie, CNRS UMR 3215, INSERM U934, 26 rue d’Ulm, 75248 Paris Cedex 05, France
| | - Charlotte Martin
- Polarity, Division and Morphogenesis Team, Institut Curie, CNRS UMR 3215, INSERM U934, 26 rue d’Ulm, 75248 Paris Cedex 05, France
| | - Yohanns Bellaiche
- Polarity, Division and Morphogenesis Team, Institut Curie, CNRS UMR 3215, INSERM U934, 26 rue d’Ulm, 75248 Paris Cedex 05, France
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Founounou N, Loyer N, Le Borgne R. Septins regulate the contractility of the actomyosin ring to enable adherens junction remodeling during cytokinesis of epithelial cells. Dev Cell 2013; 24:242-55. [PMID: 23410939 DOI: 10.1016/j.devcel.2013.01.008] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 12/05/2012] [Accepted: 01/10/2013] [Indexed: 01/01/2023]
Abstract
How adhesive contacts with neighbors may affect epithelial cell cytokinesis is unknown. We report that in Drosophila, septins are specifically required for planar (but not orthogonal) cytokinesis. During planar division, cytokinetic furrowing initiates basally, resulting in a contractile ring displaced toward the adherens junction (AJ). The formation of new AJ between daughter cells requires the disengagement of E-Cadherin complexes between mitotic and neighboring cells at the cleavage furrow, followed by the assembly of E-Cadherin complexes on the daughter-daughter interface. The strength of adhesion with neighbors directly impacts both the kinetics of AJ disengagement and the length of the new AJ. Loss of septins causes a reduction in the contractility of the actomyosin ring and prevents local disengagement of AJ in the cleavage furrow. By modulating the strength of tension induced by neighbors, we uncover a mechanical function for septins to overcome the extrinsic tension induced by neighboring interphasic cells.
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Affiliation(s)
- Nabila Founounou
- CNRS, UMR 6290, Institute of Genetics and Development of Rennes, F-35043 Rennes, France
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35
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Upadhyay A, Kandachar V, Zitserman D, Tong X, Roegiers F. Sanpodo controls sensory organ precursor fate by directing Notch trafficking and binding γ-secretase. ACTA ACUST UNITED AC 2013; 201:439-48. [PMID: 23609534 PMCID: PMC3639393 DOI: 10.1083/jcb.201209023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In sensory organ precursor cells, Sanpodo can enhance or suppress Notch signaling by promoting interaction with Presenilin or driving receptor internalization, respectively. In Drosophila peripheral neurogenesis, Notch controls cell fates in sensory organ precursor (SOP) cells. SOPs undergo asymmetric cell division by segregating Numb, which inhibits Notch signaling, into the pIIb daughter cell after cytokinesis. In contrast, in the pIIa daughter cell, Notch is activated and requires Sanpodo, but its mechanism of action has not been elucidated. As Sanpodo is present in both pIIa and pIIb cells, a second role for Sanpodo in regulating Notch signaling in the low-Notch pIIb cell has been proposed. Here we demonstrate that Sanpodo regulates Notch signaling levels in both pIIa and pIIb cells via distinct mechanisms. The interaction of Sanpodo with Presenilin, a component of the γ-secretase complex, was required for Notch activation and pIIa cell fate. In contrast, Sanpodo suppresses Notch signaling in the pIIb cell by driving Notch receptor internalization. Together, these results demonstrate that a single protein can regulate Notch signaling through distinct mechanisms to either promote or suppress signaling depending on the local cellular context.
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Affiliation(s)
- Alok Upadhyay
- Fox Chase Cancer Center, Philadelphia, PA 19111, USA
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36
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Egger B, van Giesen L, Moraru M, Sprecher SG. In vitro imaging of primary neural cell culture from Drosophila. Nat Protoc 2013; 8:958-65. [DOI: 10.1038/nprot.2013.052] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Cotton M, Benhra N, Le Borgne R. Numb Inhibits the Recycling of Sanpodo in Drosophila Sensory Organ Precursor. Curr Biol 2013; 23:581-7. [DOI: 10.1016/j.cub.2013.02.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Revised: 12/10/2012] [Accepted: 02/08/2013] [Indexed: 10/27/2022]
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Couturier L, Mazouni K, Schweisguth F. Numb localizes at endosomes and controls the endosomal sorting of notch after asymmetric division in Drosophila. Curr Biol 2013; 23:588-93. [PMID: 23523245 DOI: 10.1016/j.cub.2013.03.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 02/04/2013] [Accepted: 03/01/2013] [Indexed: 01/05/2023]
Abstract
Numb acts as a cell-fate determinant during asymmetric and stem cell divisions in both vertebrates and invertebrates [1, 2]. In Drosophila, Numb is unequally segregated in asymmetrically dividing sensory organ precursor cells (SOPs). Numb is inherited by the pIIb cell (Notch OFF) and is absent from the pIIa cell (Notch ON) [3, 4]. Numb is required to establish directional Notch signaling during cytokinesis [3, 5-7]. Using real-time imaging of a functional GFP-tagged Numb, we show that Numb relocalizes during cytokinesis from the basal cortex of pIIb to subapical endosomes. This relocalization appeared to depend on its interaction with the α-adaptin [8, 9]. Live imaging of Sanpodo (Spdo), a membrane protein interacting with Numb and regulating the trafficking of Notch [6, 7, 10-15], revealed that Spdo is internalized during cytokinesis and coaccumulates with Numb in pIIb endosomes. Using a GFP-tagged Notch [6], we found that Notch coaccumulates with Spdo in a Numb-dependent manner in these pIIb endosomes. Numb was, however, dispensable for the internalization of Notch and Spdo. We propose that Numb interacts with internalized Spdo-Notch oligomers at sorting endosomes and inhibits the recycling of Notch, thereby creating an asymmetry in Notch distribution along the pIIa-pIIb interface and regulating binary fate choice.
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Affiliation(s)
- Lydie Couturier
- Developmental and Stem Cell Biology Department, Institut Pasteur, 75015 Paris, France
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Badsha F, Kain P, Prabhakar S, Sundaram S, Padinjat R, Rodrigues V, Hasan G. Mutants in Drosophila TRPC channels reduce olfactory sensitivity to carbon dioxide. PLoS One 2012; 7:e49848. [PMID: 23185459 PMCID: PMC3501451 DOI: 10.1371/journal.pone.0049848] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 10/14/2012] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND Members of the canonical Transient Receptor Potential (TRPC) class of cationic channels function downstream of Gαq and PLCβ in Drosophila photoreceptors for transducing visual stimuli. Gαq has recently been implicated in olfactory sensing of carbon dioxide (CO(2)) and other odorants. Here we investigated the role of PLCβ and TRPC channels for sensing CO(2) in Drosophila. METHODOLOGY/PRINCIPAL FINDINGS Through behavioral assays it was demonstrated that Drosophila mutants for plc21c, trp and trpl have a reduced sensitivity for CO(2). Immuno-histochemical staining for TRP, TRPL and TRPγ indicates that all three channels are expressed in Drosophila antennae including the sensory neurons that express CO(2) receptors. Electrophysiological recordings obtained from the antennae of protein null alleles of TRP (trp(343)) and TRPL (trpl(302)), showed that the sensory response to multiple concentrations of CO(2) was reduced. However, trpl(302); trp(343) double mutants still have a residual response to CO(2). Down-regulation of TRPC channels specifically in CO(2) sensing olfactory neurons reduced the response to CO(2) and this reduction was obtained even upon down-regulation of the TRPCs in adult olfactory sensory neurons. Thus the reduced response to CO(2) obtained from the antennae of TRPC RNAi strains is not due to a developmental defect. CONCLUSION These observations show that reduction in TRPC channel function significantly reduces the sensitivity of the olfactory response to CO(2) concentrations of 5% or less in adult Drosophila. It is possible that the CO(2) receptors Gr63a and Gr21a activate the TRPC channels through Gαq and PLC21C.
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Affiliation(s)
- Farhath Badsha
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka, India
| | - Pinky Kain
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka, India
| | - Sunil Prabhakar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka, India
| | | | - Raghu Padinjat
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka, India
| | - Veronica Rodrigues
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka, India
- Department of Biological Sciences, Tata Institute of Fundamental Research, Mumbai, Maharashtra, India
| | - Gaiti Hasan
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka, India
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Kandachar V, Roegiers F. Endocytosis and control of Notch signaling. Curr Opin Cell Biol 2012; 24:534-40. [PMID: 22818956 DOI: 10.1016/j.ceb.2012.06.006] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 06/19/2012] [Accepted: 06/21/2012] [Indexed: 02/06/2023]
Abstract
The Notch signaling pathway controls patterning and cell fate decisions during development in metazoans, and is associated with human diseases such as cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and certain cancers. Studies over the last several years have revealed sophisticated regulation of both the membrane-bound Notch receptor and its ligands by vesicle trafficking. This is perhaps most evident in neural progenitor cells in Drosophila, which divide asymmetrically to segregate Numb, an endocytic adaptor protein that acts as a Notch pathway inhibitor, to one daughter cell. Here, we discuss recent findings addressing how receptor and ligand trafficking to specific membrane compartments control activation of the Notch pathway in asymmetrically dividing cells and other tissues.
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Affiliation(s)
- Vasundhara Kandachar
- Program in Cancer Biology, Fox Chase Cancer Center, Philadelphia, PA 19111, United States
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Song Y, Lu B. Interaction of Notch signaling modulator Numb with α-Adaptin regulates endocytosis of Notch pathway components and cell fate determination of neural stem cells. J Biol Chem 2012; 287:17716-17728. [PMID: 22474327 DOI: 10.1074/jbc.m112.360719] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The ability to balance self-renewal and differentiation is a hallmark of stem cells. In Drosophila neural stem cells (NSCs), Numb/Notch (N) signaling plays a key role in this process. However, the molecular and cellular mechanisms underlying Numb function in a stem cell setting remain poorly defined. Here we show that α-Adaptin (α-Ada), a subunit of the endocytic AP-2 complex, interacts with Numb through a new mode of interaction to regulate NSC homeostasis. In α-ada mutants, N pathway component Sanpodo and the N receptor itself exhibited altered trafficking, and N signaling was up-regulated in the intermediate progenitors of type II NSC lineages, leading to their transformation into ectopic NSCs. Surprisingly, although the Ear domain of α-Ada interacts with the C terminus of Numb and is important for α-Ada function in the sensory organ precursor lineage, it was dispensable in the NSCs. Instead, α-Ada could regulate Sanpodo, N trafficking, and NSC homeostasis by interacting with Numb through new domains in both proteins previously not known to mediate their interaction. This interaction could be bypassed when α-Ada was directly fused to the phospho-tyrosine binding domain of Numb. Our results identify a critical role for the AP-2-mediated endocytosis in regulating NSC behavior and reveal a new mechanism by which Numb regulates NSC behavior through N. These findings are likely to have important implications for cancer biology.
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Affiliation(s)
- Yan Song
- Department of Pathology, Stanford University School of Medicine, Stanford, California 94305
| | - Bingwei Lu
- Department of Pathology, Stanford University School of Medicine, Stanford, California 94305.
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Couturier L, Vodovar N, Schweisguth F. Endocytosis by Numb breaks Notch symmetry at cytokinesis. Nat Cell Biol 2012; 14:131-9. [PMID: 22267085 DOI: 10.1038/ncb2419] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 12/12/2011] [Indexed: 01/02/2023]
Abstract
Cell-fate diversity can be generated by the unequal segregation of the Notch regulator Numb at mitosis in both vertebrates and invertebrates. Whereas the mechanisms underlying unequal inheritance of Numb are understood, how Numb antagonizes Notch has remained unsolved. Live imaging of Notch in sensory organ precursor cells revealed that nuclear Notch is detected at cytokinesis in the daughter cell that does not inherit Numb. Numb and Sanpodo act together to regulate Notch trafficking and establish directional Notch signalling at cytokinesis. We propose that unequal segregation of Numb results in increased endocytosis in one daughter cell, hence asymmetry of Notch at the cytokinetic furrow, directional signalling and binary fate choice.
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Affiliation(s)
- Lydie Couturier
- Institut Pasteur, Developmental Biology Department, F-75015 Paris, France
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Cheutin T, Cavalli G. Progressive polycomb assembly on H3K27me3 compartments generates polycomb bodies with developmentally regulated motion. PLoS Genet 2012; 8:e1002465. [PMID: 22275876 PMCID: PMC3262012 DOI: 10.1371/journal.pgen.1002465] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 11/22/2011] [Indexed: 11/24/2022] Open
Abstract
Polycomb group (PcG) proteins are conserved chromatin factors that maintain silencing of key developmental genes outside of their expression domains. Recent genome-wide analyses showed a Polycomb (PC) distribution with binding to discrete PcG response elements (PREs). Within the cell nucleus, PcG proteins localize in structures called PC bodies that contain PcG-silenced genes, and it has been recently shown that PREs form local and long-range spatial networks. Here, we studied the nuclear distribution of two PcG proteins, PC and Polyhomeotic (PH). Thanks to a combination of immunostaining, immuno-FISH, and live imaging of GFP fusion proteins, we could analyze the formation and the mobility of PC bodies during fly embryogenesis as well as compare their behavior to that of the condensed fraction of euchromatin. Immuno-FISH experiments show that PC bodies mainly correspond to 3D structural counterparts of the linear genomic domains identified in genome-wide studies. During early embryogenesis, PC and PH progressively accumulate within PC bodies, which form nuclear structures localized on distinct euchromatin domains containing histone H3 tri-methylated on K27. Time-lapse analysis indicates that two types of motion influence the displacement of PC bodies and chromatin domains containing H2Av-GFP. First, chromatin domains and PC bodies coordinately undergo long-range motions that may correspond to the movement of whole chromosome territories. Second, each PC body and chromatin domain has its own fast and highly constrained motion. In this motion regime, PC bodies move within volumes slightly larger than those of condensed chromatin domains. Moreover, both types of domains move within volumes much smaller than chromosome territories, strongly restricting their possibility of interaction with other nuclear structures. The fast motion of PC bodies and chromatin domains observed during early embryogenesis strongly decreases in late developmental stages, indicating a possible contribution of chromatin dynamics in the maintenance of stable gene silencing. The three-dimensional organization of genes and associated proteins is critical for gene regulation. Polycomb group proteins are important developmental regulators controlling the expression of hundreds of genes. They are not homogeneously distributed in the cell nucleus, instead forming nuclear subcompartments called Polycomb bodies. We investigated the dynamics of Polycomb bodies during Drosophila embryonic development, demonstrating that two Polycomb proteins, Polycomb and Polyhomeotic, gradually assemble onto bodies enriched in histone H3 trimethylated on lysine 27, a hallmark of Polycomb silencing. Polycomb bodies are not the most condensed euchromatic part of the genome. Instead, a large amount of genomic chromatin is organized in a histone- and DNA–dense structure distinct from Polycomb bodies. Polycomb bodies move, meet, and split dynamically during development. Their motion has two regimes: a fast, highly constrained motion and a slower regime where multiple bodies undergo long-range coordinated movements potentially corresponding to chromosome territory movements. These regimes are not restricted to Polycomb but also extend to bulk “condensed euchromatin,” which is characterized by slower motion and a narrower radius of confinement. Both motion regimes progressively slow down during development, suggesting that regulation of chromatin dynamics may play an important role in the maintenance of gene silencing in differentiated cells.
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Affiliation(s)
- Thierry Cheutin
- Institut de Génétique Humaine, CNRS UPR 1142, Montpellier, France
| | - Giacomo Cavalli
- Institut de Génétique Humaine, CNRS UPR 1142, Montpellier, France
- * E-mail:
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Giagtzoglou N, Yamamoto S, Zitserman D, Graves HK, Schulze KL, Wang H, Klein H, Roegiers F, Bellen HJ. dEHBP1 controls exocytosis and recycling of Delta during asymmetric divisions. ACTA ACUST UNITED AC 2012; 196:65-83. [PMID: 22213802 PMCID: PMC3255984 DOI: 10.1083/jcb.201106088] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Drosophila EHBP1 is a novel regulator of Notch signaling that may function as an adaptor protein during the exocytosis and recycling of the Notch ligand Delta. Notch signaling governs binary cell fate determination in asymmetrically dividing cells. Through a forward genetic screen we identified the fly homologue of Eps15 homology domain containing protein-binding protein 1 (dEHBP1) as a novel regulator of Notch signaling in asymmetrically dividing cells. dEHBP1 is enriched basally and at the actin-rich interface of pII cells of the external mechanosensory organs, where Notch signaling occurs. Loss of function of dEHBP1 leads to up-regulation of Sanpodo, a regulator of Notch signaling, and aberrant trafficking of the Notch ligand, Delta. Furthermore, Sec15 and Rab11, which have been previously shown to regulate the localization of Delta, physically interact with dEHBP1. We propose that dEHBP1 functions as an adaptor molecule for the exocytosis and recycling of Delta, thereby affecting cell fate decisions in asymmetrically dividing cells.
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Affiliation(s)
- Nikolaos Giagtzoglou
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA
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Le Bras S, Rondanino C, Kriegel-Taki G, Dussert A, Le Borgne R. Genetic identification of intracellular trafficking regulators involved in notch dependent binary cell fate acquisition following asymmetric cell division. J Cell Sci 2012; 125:4886-901. [DOI: 10.1242/jcs.110171] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Notch signaling is involved in numerous cellular processes during development and throughout adult life. Although ligands and receptors are largely expressed in the whole organism, activation of Notch receptors only takes place in a subset of cells and/or tissues and is accurately regulated in time and space. Previous studies have demonstrated that endocytosis and recycling of both ligands and/or receptors are essential for this regulation. However, the precise endocytic routes, compartments and regulators involved in the spatio temporal regulation are largely unknown.
In order to identify Notch signaling intracellular trafficking regulators, we have undertaken a tissue-specific dsRNA genetic screen against candidates potentially involved in endocytosis and recycling within the endolysosomal pathway. dsRNA against 418 genes was induced in Drosophila melanogaster sensory organ lineage in which Notch signaling regulates binary cell fate acquisition. Gain- or loss-of Notch signaling phenotypes were observed in adult sensory organs for 113 of them. Furthermore, 26 genes presented a change in the steady state localization of Notch, Sanpodo, a Notch co-factor, and/or Delta in the pupal lineage. In particular, we identified 20 genes with previously unknown function in Drosophila melanogaster intracellular trafficking. Among them, we identified CG2747 and show that it regulates the localization of clathrin adaptor AP-1 complex, a negative regulator of Notch signaling. All together, our results further demonstrate the essential function of intracellular trafficking in regulating Notch signaling-dependent binary cell fate acquisition and constitute an additional step toward the elucidation of the routes followed by Notch receptor and ligands to signal.
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Abstract
The Golgi is essential for processing proteins and sorting them, as well as plasma membrane components, to their final destinations. Not surprisingly, this organelle, a major compartment of the secretory pathway, is an important venue for regulating many aspects of development in both invertebrates and vertebrates. Through its role as a site for protein cleavage and glycosylation as well as through changes in its spatial organization and secretory trafficking, the Golgi exerts highly specific effects on cellular differentiation and morphogenesis by spatially and temporally constraining developmental pathways.
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Chell JM, Brand AH. Nutrition-responsive glia control exit of neural stem cells from quiescence. Cell 2011; 143:1161-73. [PMID: 21183078 PMCID: PMC3087489 DOI: 10.1016/j.cell.2010.12.007] [Citation(s) in RCA: 284] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Revised: 11/17/2010] [Accepted: 12/07/2010] [Indexed: 11/28/2022]
Abstract
The systemic regulation of stem cells ensures that they meet the needs of the organism during growth and in response to injury. A key point of regulation is the decision between quiescence and proliferation. During development, Drosophila neural stem cells (neuroblasts) transit through a period of quiescence separating distinct embryonic and postembryonic phases of proliferation. It is known that neuroblasts exit quiescence via a hitherto unknown pathway in response to a nutrition-dependent signal from the fat body. We have identified a population of glial cells that produce insulin/IGF-like peptides in response to nutrition, and we show that the insulin/IGF receptor pathway is necessary for neuroblasts to exit quiescence. The forced expression of insulin/IGF-like peptides in glia, or activation of PI3K/Akt signaling in neuroblasts, can drive neuroblast growth and proliferation in the absence of dietary protein and thus uncouple neuroblasts from systemic control.
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Affiliation(s)
- James M Chell
- The Gurdon Institute and Department of Physiology, Development, and Neuroscience, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
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48
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Benhra N, Lallet S, Cotton M, Le Bras S, Dussert A, Le Borgne R. AP-1 controls the trafficking of Notch and Sanpodo toward E-cadherin junctions in sensory organ precursors. Curr Biol 2010; 21:87-95. [PMID: 21194948 DOI: 10.1016/j.cub.2010.12.010] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 11/11/2010] [Accepted: 12/06/2010] [Indexed: 02/01/2023]
Abstract
In Drosophila melanogaster, external sensory organs develop from a single sensory organ precursor (SOP). The SOP divides asymmetrically to generate daughter cells, whose fates are governed by differential Notch activation. Here we show that the clathrin adaptor AP-1 complex, localized at the trans Golgi network and in recycling endosomes, acts as a negative regulator of Notch signaling. Inactivation of AP-1 causes ligand-dependent activation of Notch, leading to a fate transformation within sensory organs. Loss of AP-1 affects neither cell polarity nor the unequal segregation of the cell fate determinants Numb and Neuralized. Instead, it causes apical accumulation of the Notch activator Sanpodo and stabilization of both Sanpodo and Notch at the interface between SOP daughter cells, where DE-cadherin is localized. Endocytosis-recycling assays reveal that AP-1 acts in recycling endosomes to prevent internalized Spdo from recycling toward adherens junctions. Because AP-1 does not prevent endocytosis and recycling of the Notch ligand Delta, our data indicate that the DE-cadherin junctional domain may act as a launching pad through which endocytosed Notch ligand is trafficked for signaling.
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Affiliation(s)
- Najate Benhra
- CNRS UMR 6061-Institut de Génétique et Développement de Rennes, Université de Rennes 1, 2 avenue du Professeur Bernard, 35000 Rennes, France
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The Fz-Dsh planar cell polarity pathway induces oriented cell division via Mud/NuMA in Drosophila and zebrafish. Dev Cell 2010; 19:740-52. [PMID: 21074723 PMCID: PMC3008569 DOI: 10.1016/j.devcel.2010.10.004] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 08/27/2010] [Accepted: 10/02/2010] [Indexed: 01/20/2023]
Abstract
The Frizzled receptor and Dishevelled effector regulate mitotic spindle orientation in both vertebrates and invertebrates, but how Dishevelled orients the mitotic spindle is unknown. Using the Drosophila S2 cell "induced polarity" system, we find that Dishevelled cortical polarity is sufficient to orient the spindle and that Dishevelled's DEP domain mediates this function. This domain binds a C-terminal domain of Mud (the Drosophila NuMA ortholog), and Mud is required for Dishevelled-mediated spindle orientation. In Drosophila, Frizzled-Dishevelled planar cell polarity (PCP) orients the sensory organ precursor (pI) spindle along the anterior-posterior axis. We show that Dishevelled and Mud colocalize at the posterior cortex of pI, Mud localization at the posterior cortex requires Dsh, and Mud loss-of-function randomizes spindle orientation. During zebrafish gastrulation, the Wnt11-Frizzled-Dishevelled PCP pathway orients spindles along the animal-vegetal axis, and reducing NuMA levels disrupts spindle orientation. Overall, we describe a Frizzled-Dishevelled-NuMA pathway that orients division from Drosophila to vertebrates.
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50
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de Pontual L, Lyonnet S, Amiel J. [Malformation syndromes associated with childhood cancer: an update]. Arch Pediatr 2010; 17:1220-7. [PMID: 20598868 DOI: 10.1016/j.arcped.2010.05.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Revised: 04/16/2010] [Accepted: 05/25/2010] [Indexed: 10/19/2022]
Abstract
Biology, genetics and environment of childhood solid tumours set them apart from adult solid tumours. The nature of the progenitor cells from which these tumours arise, and their immature tissue environment, allows childhood solid tumours to develop with fewer defects in cell regulatory processes. Constitutional molecular defects are known to play a role in childhood solid tumours, as shown by the increased incidence of embryonic cancers in children carrying malformations associated with childhood cancer. These rare diagnoses are commonly missed. In this article, we reviewed the spectrum of these tumour predisposition syndromes.
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Affiliation(s)
- L de Pontual
- Service de pédiatrie, hôpital Jean-Verdier, AP-HP, université Paris XIII, 14, avenue du 14-Juillet, 93143 Bondy, France.
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