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Wu J, Bala Tannan N, Vuong LT, Koca Y, Collu GM, Mlodzik M. Par3/bazooka binds NICD and promotes notch signaling during Drosophila development. Dev Biol 2024; 514:37-49. [PMID: 38885804 DOI: 10.1016/j.ydbio.2024.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 04/01/2024] [Accepted: 06/14/2024] [Indexed: 06/20/2024]
Abstract
The conserved bazooka (baz/par3) gene acts as a key regulator of asymmetrical cell divisions across the animal kingdom. Associated Par3/Baz-Par6-aPKC protein complexes are also well known for their role in the establishment of apical/basal cell polarity in epithelial cells. Here we define a novel, positive function of Baz/Par3 in the Notch pathway. Using Drosophila wing and eye development, we demonstrate that Baz is required for Notch signaling activity and optimal transcriptional activation of Notch target genes. Baz appears to act independently of aPKC in these contexts, as knockdown of aPKC does not cause Notch loss-of-function phenotypes. Using transgenic Notch constructs, our data positions Baz activity downstream of activating Notch cleavage steps and upstream of Su(H)/CSL transcription factor complex activity on Notch target genes. We demonstrate a biochemical interaction between NICD and Baz, suggesting that Baz is required for NICD activity before NICD binds to Su(H). Taken together, our data define a novel role of the polarity protein Baz/Par3, as a positive and direct regulator of Notch signaling through its interaction with NICD.
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Affiliation(s)
- Jun Wu
- Dept. of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
| | - Neeta Bala Tannan
- Dept. of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
| | - Linh T Vuong
- Dept. of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
| | - Yildiz Koca
- Dept. of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
| | - Giovanna M Collu
- Dept. of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
| | - Marek Mlodzik
- Dept. of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA.
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2
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Houssin E, Pinot M, Bellec K, Le Borgne R. Par3 cooperates with Sanpodo for the assembly of Notch clusters following asymmetric division of Drosophila sensory organ precursor cells. eLife 2021; 10:e66659. [PMID: 34596529 PMCID: PMC8516416 DOI: 10.7554/elife.66659] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 09/25/2021] [Indexed: 12/15/2022] Open
Abstract
In multiple cell lineages, Delta-Notch signalling regulates cell fate decisions owing to unidirectional signalling between daughter cells. In Drosophila pupal sensory organ lineage, Notch regulates the intra-lineage pIIa/pIIb fate decision at cytokinesis. Notch and Delta that localise apically and basally at the pIIa-pIIb interface are expressed at low levels and their residence time at the plasma membrane is in the order of minutes. How Delta can effectively interact with Notch to trigger signalling from a large plasma membrane area remains poorly understood. Here, we report that the signalling interface possesses a unique apico-basal polarity with Par3/Bazooka localising in the form of nano-clusters at the apical and basal level. Notch is preferentially targeted to the pIIa-pIIb interface, where it co-clusters with Bazooka and its cofactor Sanpodo. Clusters whose assembly relies on Bazooka and Sanpodo activities are also positive for Neuralized, the E3 ligase required for Delta activity. We propose that the nano-clusters act as snap buttons at the new pIIa-pIIb interface to allow efficient intra-lineage signalling.
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Affiliation(s)
- Elise Houssin
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, F- 35000RennesFrance
- Equipe Labellisée Ligue Nationale contre le cancerGlasgowUnited Kingdom
| | - Mathieu Pinot
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, F- 35000RennesFrance
- Equipe Labellisée Ligue Nationale contre le cancerGlasgowUnited Kingdom
| | - Karen Bellec
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, F- 35000RennesFrance
- Equipe Labellisée Ligue Nationale contre le cancerGlasgowUnited Kingdom
| | - Roland Le Borgne
- Univ Rennes, CNRS, IGDR (Institut de Génétique et Développement de Rennes) - UMR 6290, F- 35000RennesFrance
- Equipe Labellisée Ligue Nationale contre le cancerGlasgowUnited Kingdom
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3
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Thompson BJ. Par-3 family proteins in cell polarity & adhesion. FEBS J 2021; 289:596-613. [PMID: 33565714 PMCID: PMC9290619 DOI: 10.1111/febs.15754] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 01/19/2021] [Accepted: 02/08/2021] [Indexed: 12/27/2022]
Abstract
The Par‐3/Baz family of polarity determinants is highly conserved across metazoans and includes C. elegans PAR‐3, Drosophila Bazooka (Baz), human Par‐3 (PARD3), and human Par‐3‐like (PARD3B). The C. elegans PAR‐3 protein localises to the anterior pole of asymmetrically dividing zygotes with cell division cycle 42 (CDC42), atypical protein kinase C (aPKC), and PAR‐6. The same C. elegans ‘PAR complex’ can also localise in an apical ring in epithelial cells. Drosophila Baz localises to the apical pole of asymmetrically dividing neuroblasts with Cdc42‐aPKC‐Par6, while in epithelial cells localises both in an apical ring with Cdc42‐aPKC‐Par6 and with E‐cadherin at adherens junctions. These apical and junctional localisations have become separated in human PARD3, which is strictly apical in many epithelia, and human PARD3B, which is strictly junctional in many epithelia. We discuss the molecular basis for this fundamental difference in localisation, as well as the possible functions of Par‐3/Baz family proteins as oligomeric clustering agents at the apical domain or at adherens junctions in epithelial stem cells. The evolution of Par‐3 family proteins into distinct apical PARD3 and junctional PARD3B orthologs coincides with the emergence of stratified squamous epithelia in vertebrates, where PARD3B, but not PARD3, is strongly expressed in basal layer stem cells – which lack a typical apical domain. We speculate that PARD3B may contribute to clustering of E‐cadherin, signalling from adherens junctions via Src family kinases or mitotic spindle orientation by adherens junctions in response to mechanical forces.
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Affiliation(s)
- Barry J Thompson
- ACRF Department of Cancer Biology & Therapeutics, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
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4
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Sun J, Stathopoulos A. FGF controls epithelial-mesenchymal transitions during gastrulation by regulating cell division and apicobasal polarity. Development 2018; 145:dev.161927. [PMID: 30190277 DOI: 10.1242/dev.161927] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 08/31/2018] [Indexed: 01/06/2023]
Abstract
To support tissue and organ development, cells transition between epithelial and mesenchymal states. Here, we have investigated how mesoderm cells change state in Drosophila embryos and whether fibroblast growth factor (FGF) signaling plays a role. During gastrulation, presumptive mesoderm cells invaginate, undergo an epithelial-to-mesenchymal state transition (EMT) and migrate upon the ectoderm. Our data show that EMT is a prolonged process in which adherens junctions progressively decrease in number throughout the migration of mesoderm cells. FGF influences adherens junction number and promotes mesoderm cell division, which we propose decreases cell-cell attachments to support slow EMT while retaining collective cell movement. We also found that, at the completion of migration, cells form a monolayer and undergo a reverse mesenchymal-to-epithelial transition (MET). FGF activity leads to accumulation of β-integrin Myospheroid basally and cell polarity factor Bazooka apically within mesoderm cells, thereby reestablishing apicobasal cell polarity in an epithelialized state in which cells express both E-Cadherin and N-Cadherin. In summary, FGF plays a dynamic role in supporting mesoderm cell development to ensure collective mesoderm cell movements, as well as proper differentiation of mesoderm cell types.
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Affiliation(s)
- Jingjing Sun
- California Institute of Technology, Division of Biology and Biological Engineering, 1200 East California Boulevard, Pasadena, CA 91125, USA
| | - Angelike Stathopoulos
- California Institute of Technology, Division of Biology and Biological Engineering, 1200 East California Boulevard, Pasadena, CA 91125, USA
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5
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Banerjee JJ, Aerne BL, Holder MV, Hauri S, Gstaiger M, Tapon N. Meru couples planar cell polarity with apical-basal polarity during asymmetric cell division. eLife 2017; 6:e25014. [PMID: 28665270 PMCID: PMC5493435 DOI: 10.7554/elife.25014] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 06/14/2017] [Indexed: 12/15/2022] Open
Abstract
Polarity is a shared feature of most cells. In epithelia, apical-basal polarity often coexists, and sometimes intersects with planar cell polarity (PCP), which orients cells in the epithelial plane. From a limited set of core building blocks (e.g. the Par complexes for apical-basal polarity and the Frizzled/Dishevelled complex for PCP), a diverse array of polarized cells and tissues are generated. This suggests the existence of little-studied tissue-specific factors that rewire the core polarity modules to the appropriate conformation. In Drosophila sensory organ precursors (SOPs), the core PCP components initiate the planar polarization of apical-basal determinants, ensuring asymmetric division into daughter cells of different fates. We show that Meru, a RASSF9/RASSF10 homologue, is expressed specifically in SOPs, recruited to the posterior cortex by Frizzled/Dishevelled, and in turn polarizes the apical-basal polarity factor Bazooka (Par3). Thus, Meru belongs to a class of proteins that act cell/tissue-specifically to remodel the core polarity machinery.
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Affiliation(s)
- Jennifer J Banerjee
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Birgit L Aerne
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Maxine V Holder
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Simon Hauri
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, Zürich, Switzerland
- Competence Center Personalized Medicine UZH/ETH, Zürich, Switzerland
| | - Matthias Gstaiger
- Department of Biology, Institute of Molecular Systems Biology, ETH Zürich, Zürich, Switzerland
- Competence Center Personalized Medicine UZH/ETH, Zürich, Switzerland
| | - Nicolas Tapon
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, London, United Kingdom
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6
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7
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Bhat KM. Notch signaling acts before cell division to promote asymmetric cleavage and cell fate of neural precursor cells. Sci Signal 2014; 7:ra101. [DOI: 10.1126/scisignal.2005317] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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8
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Mauri F, Reichardt I, Mummery-Widmer JL, Yamazaki M, Knoblich JA. The conserved discs-large binding partner Banderuola regulates asymmetric cell division in Drosophila. Curr Biol 2014; 24:1811-25. [PMID: 25088559 DOI: 10.1016/j.cub.2014.06.059] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 03/08/2014] [Accepted: 06/23/2014] [Indexed: 12/26/2022]
Abstract
BACKGROUND Asymmetric cell division (ACD) is a key process that allows different cell types to be generated at precisely defined times and positions. In Drosophila, neural precursor cells rely heavily on ACD to generate the different cell types in the nervous system. A conserved protein machinery that regulates ACD has been identified in Drosophila, but how this machinery acts to allow the establishment of differential cell fates is not entirely understood. RESULTS To identify additional proteins required for ACD, we have carried out an in vivo live imaging RNAi screen for genes affecting the asymmetric segregation of Numb in Drosophila sensory organ precursor cells. We identify Banderuola (Bnd), an essential regulator of cell polarization, spindle orientation, and asymmetric protein localization in Drosophila neural precursor cells. Genetic and biochemical experiments show that Bnd acts together with the membrane-associated tumor suppressor Discs-large (Dlg) to establish antagonistic cortical domains during ACD. Inhibiting Bnd strongly enhances the dlg phenotype, causing massive brain tumors upon knockdown of both genes. Because the mammalian homologs of Bnd and Dlg are interacting as well, Bnd function might be conserved in vertebrates, and it might also regulate cell polarity in higher organisms. CONCLUSIONS Bnd is a novel regulator of ACD in different types of cells. Our data place Bnd at the top of the hierarchy of the factors involved in ACD, suggesting that its main function is to mediate the localization and function of the Dlg tumor suppressor. Bnd has an antioncogenic function that is redundant with Dlg, and the physical interaction between the two proteins is conserved in evolution.
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Affiliation(s)
- Federico Mauri
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna 1030, Austria
| | - Ilka Reichardt
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna 1030, Austria
| | | | - Masakazu Yamazaki
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna 1030, Austria
| | - Juergen A Knoblich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna 1030, Austria.
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9
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Montagne C, Gonzalez-Gaitan M. Sara endosomes and the asymmetric division of intestinal stem cells. Development 2014; 141:2014-23. [PMID: 24803650 DOI: 10.1242/dev.104240] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Tissue homeostasis is maintained by adult stem cells, which self-renew and give rise to differentiating cells. The generation of daughter cells with different fates is mediated by signalling molecules coming from an external niche or being asymmetrically dispatched between the two daughters upon stem cell mitosis. In the adult Drosophila midgut, the intestinal stem cell (ISC) divides to generate a new ISC and an enteroblast (EB) differentiating daughter. Notch signalling activity restricted to the EB regulates intestinal cell fate decision. Here, we show that ISCs divide asymmetrically, and Sara endosomes in ISCs are specifically dispatched to the presumptive EB. During ISC mitosis, Notch and Delta traffic through Sara endosomes, thereby contributing to Notch signalling bias, as revealed in Sara mutants: Sara itself contributes to the control of the ISC asymmetric division. Our data uncover an intrinsic endosomal mechanism during ISC mitosis, which participates in the maintenance of the adult intestinal lineage.
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Affiliation(s)
- Chrystelle Montagne
- Department of Biochemistry, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland
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10
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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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11
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Abstract
In the Drosophila embryonic central nervous system, the neural precursor cells called neuroblasts undergo a number of asymmetric divisions along the apical-basal axis to give rise to different daughter cells of distinct fates. This review summarizes recent progress in understanding the mechanisms of these asymmetric cell divisions. We discuss proteins that are localized at distinct domains of cortex in the neuroblasts and their role in generating asymmetry. We also review uniformly cortical localized factors and actin cytoskeleton-associated motor proteins with regard to their potential role to serve as a link between distinct cortical domains in the neuroblasts. In this review, asymmetric divisions of sensory organ precursor and larval neuroblasts are also briefly discussed.
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Affiliation(s)
- Hongyan Wang
- Temasek Life Sciences Laboratory, 1 Research Link, The National University of Singapore, Singapore 117604
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12
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13
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Zitserman D, Roegiers F. Live-cell imaging of sensory organ precursor cells in intact Drosophila pupae. J Vis Exp 2011:2706. [PMID: 21654627 PMCID: PMC3125114 DOI: 10.3791/2706] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Since the discovery of Green Fluorescent Protein (GFP), there has been a revolutionary change in the use of live-cell imaging as a tool for understanding fundamental biological mechanisms. Striking progress has been particularly evident in Drosophila, whose extensive toolkit of mutants and transgenic lines provides a convenient model to study evolutionarily-conserved developmental and cell biological mechanisms. We are interested in understanding the mechanisms that control cell fate specification in the adult peripheral nervous system (PNS) in Drosophila. Bristles that cover the head, thorax, abdomen, legs and wings of the adult fly are individual mechanosensory organs, and have been studied as a model system for understanding mechanisms of Notch-dependent cell fate decisions. Sensory organ precursor (SOP) cells of the microchaetes (or small bristles), are distributed throughout the epithelium of the pupal thorax, and are specified during the first 12 hours after the onset of pupariation. After specification, the SOP cells begin to divide, segregating the cell fate determinant Numb to one daughter cell during mitosis. Numb functions as a cell-autonomous inhibitor of the Notch signaling pathway. Here, we show a method to follow protein dynamics in SOP cell and its progeny within the intact pupal thorax using a combination of tissue-specific Gal4 drivers and GFP-tagged fusion proteins 1,2.This technique has the advantage over fixed tissue or cultured explants because it allows us to follow the entire development of an organ from specification of the neural precursor to growth and terminal differentiation of the organ. We can therefore directly correlate changes in cell behavior to changes in terminal differentiation. Moreover, we can combine the live imaging technique with mosaic analysis with a repressible cell marker (MARCM) system to assess the dynamics of tagged proteins in mitotic SOPs under mutant or wildtype conditions. Using this technique, we and others have revealed novel insights into regulation of asymmetric cell division and the control of Notch signaling activation in SOP cells (examples include references 1-6,7 ,8).
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Affiliation(s)
- Diana Zitserman
- Epigenetics and Progenitor Cells Keystone, Fox Chase Cancer Center
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14
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Bukharina TA, Furman DP. Asymmetric cell division in the morphogenesis of Drosophila melanogaster macrochaetae. Russ J Dev Biol 2011. [DOI: 10.1134/s1062360411010036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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15
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Pece S, Confalonieri S, R Romano P, Di Fiore PP. NUMB-ing down cancer by more than just a NOTCH. BIOCHIMICA ET BIOPHYSICA ACTA 2011; 1815:26-43. [PMID: 20940030 DOI: 10.1016/j.bbcan.2010.10.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Revised: 09/30/2010] [Accepted: 10/02/2010] [Indexed: 02/07/2023]
Abstract
The protein Numb does not live up to its name. This passive-sounding protein is anything but spent. Originally identified as a cell-fate determinant in Drosophila development, Numb received a good deal of attention as an inhibitor of the Notch receptor signaling pathway. It turns out, however, that Numb does a lot more than simply regulate Notch. It has been implicated in a variety of biochemical pathways connected with signaling (it regulates Notch-, Hedgehog- and TP53-activated pathways), endocytosis (it is involved in cargo internalization and recycling), determination of polarity (it interacts with the PAR complex, and regulates adherens and tight junctions), and ubiquitination (it exploits this mechanism to regulate protein function and stability). This complex biochemical network lies at the heart of Numb's involvement in diverse cellular phenotypes, including cell fate developmental decisions, maintenance of stem cell compartments, regulation of cell polarity and adhesion, and migration. Considering its multifaceted role in cellular homeostasis, it is not surprising that Numb has been implicated in cancer as a tumor suppressor. Our major goal here is to explain the cancer-related role of Numb based on our understanding of its role in cell physiology. We will attempt to do this by reviewing the present knowledge of Numb at the biochemical and functional level, and by integrating its apparently heterogeneous functions into a unifying scenario, based on our recently proposed concept of the "endocytic matrix". Finally, we will discuss the role of Numb in the maintenance of the normal stem cell compartment, as a starting point to interpret the tumor suppressor function of Numb in the context of the cancer stem cell hypothesis.
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Affiliation(s)
- Salvatore Pece
- Fondazione Istituto FIRC di Oncologia Molecolare, Via Adamello 16, 20139, Milan, Italy
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16
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Karbowniczek M, Zitserman D, Khabibullin D, Hartman T, Yu J, Morrison T, Nicolas E, Squillace R, Roegiers F, Henske EP. The evolutionarily conserved TSC/Rheb pathway activates Notch in tuberous sclerosis complex and Drosophila external sensory organ development. J Clin Invest 2009; 120:93-102. [PMID: 20038815 DOI: 10.1172/jci40221] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Accepted: 10/21/2009] [Indexed: 01/30/2023] Open
Abstract
Mutations in either of the genes encoding the tuberous sclerosis complex (TSC), TSC1 and TSC2, result in a multisystem tumor disorder characterized by lesions with unusual lineage expression patterns. How these unusual cell-fate determination patterns are generated is unclear. We therefore investigated the role of the TSC in the Drosophila external sensory organ (ESO), a classic model of asymmetric cell division. In normal development, the sensory organ precursor cell divides asymmetrically through differential regulation of Notch signaling to produce a pIIa and a pIIb cell. We report here that inactivation of Tsc1 and overexpression of the Ras homolog Rheb each resulted in duplication of the bristle and socket cells, progeny of the pIIa cell, and loss of the neuronal cell, a product of pIIb cell division. Live imaging of ESO development revealed this cell-fate switch occurred at the pIIa-pIIb 2-cell stage. In human angiomyolipomas, benign renal neoplasms often found in tuberous sclerosis patients, we found evidence of Notch receptor cleavage and Notch target gene activation. Further, an angiomyolipoma-derived cell line carrying biallelic TSC2 mutations exhibited TSC2- and Rheb-dependent Notch activation. Finally, inhibition of Notch signaling using a gamma-secretase inhibitor suppressed proliferation of Tsc2-null rat cells in a xenograft model. Together, these data indicate that the TSC and Rheb regulate Notch-dependent cell-fate decision in Drosophila and Notch activity in mammalian cells and that Notch dysregulation may underlie some of the distinctive clinical and pathologic features of TSC.
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Affiliation(s)
- Magdalena Karbowniczek
- Institute for Cancer Research, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, USA
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17
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Erben V, Waldhuber M, Langer D, Fetka I, Jansen RP, Petritsch C. Asymmetric localization of the adaptor protein Miranda in neuroblasts is achieved by diffusion and sequential interaction of Myosin II and VI. J Cell Sci 2008; 121:1403-14. [PMID: 18398000 DOI: 10.1242/jcs.020024] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The adaptor protein Miranda plays a pivotal role in the asymmetric cell division of neuroblasts by asymmetrically segregating key differentiation factors. Miranda localization requires Myosin VI and Myosin II. The apical-then-basal localization pattern of Miranda detected in fixed tissue, and the localization defects in embryos lacking Myosin VI, suggest that Miranda is transported to the basal pole as a Myosin VI cargo. However, the mode and temporal sequence of Miranda localization have not been characterized in live embryos. Furthermore, it is unknown whether Miranda and PON, a second adaptor protein required for asymmetric protein localization, are both regulated by Myosin II. By combining immunofluorescence studies with time-lapse confocal microscopy, we show that Miranda protein forms an apical crescent at interphase, but is ubiquitously localized at prophase in a Myosin-II-dependent manner. FRAP analysis revealed that Miranda protein reaches the basal cortex by passive diffusion throughout the cell, rather than by long-range Myosin VI-directed transport. Myosin VI acts downstream of Myosin II in the same pathway to deliver diffusing Miranda to the basal cortex. PON localization occurs mainly along the cortex and requires Myosin II but not Myosin VI, suggesting that distinct mechanisms are employed to localize different adaptor proteins during asymmetric cell division.
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Affiliation(s)
- Veronika Erben
- GeneCenter, Ludwig-Maximilian-University Munich, Department of Biochemistry and Laboratory of Molecular Biology, Munich, Germany
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18
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Rebollo E, Sampaio P, Januschke J, Llamazares S, Varmark H, González C. Functionally unequal centrosomes drive spindle orientation in asymmetrically dividing Drosophila neural stem cells. Dev Cell 2007; 12:467-74. [PMID: 17336911 DOI: 10.1016/j.devcel.2007.01.021] [Citation(s) in RCA: 235] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2006] [Revised: 01/24/2007] [Accepted: 01/29/2007] [Indexed: 12/24/2022]
Abstract
Stem cell asymmetric division requires tight control of spindle orientation. To study this key process, we have recorded Drosophila larval neural stem cells (NBs) engineered to express fluorescent reporters for microtubules, pericentriolar material (PCM), and centrioles. We have found that early in the cell cycle, the two centrosomes become unequal: one organizes an aster that stays near the apical cortex for most of the cell cycle, while the other loses PCM and microtubule-organizing activity, and moves extensively throughout the cell until shortly before mitosis when, located near the basal cortex, it recruits PCM and organizes the second mitotic aster. Upon division, the apical centrosome remains in the stem cell, while the other goes into the differentiating daughter. Apical aster maintenance requires the function of Pins. These results reveal that spindle orientation in Drosophila larval NBs is determined very early in the cell cycle, and is mediated by asymmetric centrosome function.
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Affiliation(s)
- Elena Rebollo
- Cell Division Group, Institute for Research in Biomedicine, Parc Científic Barcelona, C/ Josep Samitier 1-5, 08028 Barcelona, Spain
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19
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Smith CA, Lau KM, Rahmani Z, Dho SE, Brothers G, She YM, Berry DM, Bonneil E, Thibault P, Schweisguth F, Le Borgne R, McGlade CJ. aPKC-mediated phosphorylation regulates asymmetric membrane localization of the cell fate determinant Numb. EMBO J 2007; 26:468-80. [PMID: 17203073 PMCID: PMC1783459 DOI: 10.1038/sj.emboj.7601495] [Citation(s) in RCA: 169] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Accepted: 11/14/2006] [Indexed: 01/09/2023] Open
Abstract
In Drosophila, the partition defective (Par) complex containing Par3, Par6 and atypical protein kinase C (aPKC) directs the polarized distribution and unequal segregation of the cell fate determinant Numb during asymmetric cell divisions. Unequal segregation of mammalian Numb has also been observed, but the factors involved are unknown. Here, we identify in vivo phosphorylation sites of mammalian Numb and show that both mammalian and Drosophila Numb interact with, and are substrates for aPKC in vitro. A form of mammalian Numb lacking two protein kinase C (PKC) phosphorylation sites (Numb2A) accumulates at the cell membrane and is refractory to PKC activation. In epithelial cells, mammalian Numb localizes to the basolateral membrane and is excluded from the apical domain, which accumulates aPKC. In contrast, Numb2A is distributed uniformly around the cell cortex. Mutational analysis of conserved aPKC phosphorylation sites in Drosophila Numb suggests that phosphorylation contributes to asymmetric localization of Numb, opposite to aPKC in dividing sensory organ precursor cells. These results suggest a model in which phosphorylation of Numb by aPKC regulates its polarized distribution in epithelial cells as well as during asymmetric cell divisions.
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Affiliation(s)
- Christian A Smith
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
- Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Kimberly M Lau
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
- Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Zohra Rahmani
- Ecole Normale Supérieure. CNRS UMR 8542, Paris Cedex, France
| | - Sascha E Dho
- Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Greg Brothers
- Advanced Protein Technology Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ye Min She
- Advanced Protein Technology Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Donna M Berry
- Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Eric Bonneil
- Institute for Research in Immunology and Cancer, Université de Montreal, Montreal, Quebec, Canada
| | - Pierre Thibault
- Institute for Research in Immunology and Cancer, Université de Montreal, Montreal, Quebec, Canada
| | | | | | - C Jane McGlade
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
- Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario, Canada
- Program in Cell Biology, Hospital for Sick Children, 555 University Ave, Toronto, ON, Canada, M5G 1X8. Tel.: +416 813 8657; Fax: +416 813 8456; E-mail:
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20
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Balakireva M, Rossé C, Langevin J, Chien YC, Gho M, Gonzy-Treboul G, Voegeling-Lemaire S, Aresta S, Lepesant JA, Bellaiche Y, White M, Camonis J. The Ral/exocyst effector complex counters c-Jun N-terminal kinase-dependent apoptosis in Drosophila melanogaster. Mol Cell Biol 2006; 26:8953-63. [PMID: 17000765 PMCID: PMC1636832 DOI: 10.1128/mcb.00506-06] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2006] [Revised: 05/08/2006] [Accepted: 09/11/2006] [Indexed: 11/20/2022] Open
Abstract
Ral GTPase activity is a crucial cell-autonomous factor supporting tumor initiation and progression. To decipher pathways impacted by Ral, we have generated null and hypomorph alleles of the Drosophila melanogaster Ral gene. Ral null animals were not viable. Reduced Ral expression in cells of the sensory organ lineage had no effect on cell division but led to postmitotic cell-specific apoptosis. Genetic epistasis and immunofluorescence in differentiating sensory organs suggested that Ral activity suppresses c-Jun N-terminal kinase (JNK) activation and induces p38 mitogen-activated protein (MAP) kinase activation. HPK1/GCK-like kinase (HGK), a MAP kinase kinase kinase kinase that can drive JNK activation, was found as an exocyst-associated protein in vivo. The exocyst is a Ral effector, and the epistasis between mutants of Ral and of msn, the fly ortholog of HGK, suggest the functional relevance of an exocyst/HGK interaction. Genetic analysis also showed that the exocyst is required for the execution of Ral function in apoptosis. We conclude that in Drosophila Ral counters apoptotic programs to support cell fate determination by acting as a negative regulator of JNK activity and a positive activator of p38 MAP kinase. We propose that the exocyst complex is Ral executioner in the JNK pathway and that a cascade from Ral to the exocyst to HGK would be a molecular basis of Ral action on JNK.
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Affiliation(s)
- Maria Balakireva
- Institut Curie, INSERM U528, Groupe d'Analyse des Réseaux de Transduction (ART), 26 rue d'Ulm, 75248 Paris cedex 05, France
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21
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Dho SE, Trejo J, Siderovski DP, McGlade CJ. Dynamic regulation of mammalian numb by G protein-coupled receptors and protein kinase C activation: Structural determinants of numb association with the cortical membrane. Mol Biol Cell 2006; 17:4142-55. [PMID: 16837553 PMCID: PMC1593178 DOI: 10.1091/mbc.e06-02-0097] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The cell fate determinant Numb is a membrane-associated adaptor protein involved in both development and intracellular vesicular trafficking. It has a phosphotyrosine-binding (PTB) domain and COOH-terminal endocytic-binding motifs for alpha-adaptin and Eps15 homology domain-containing proteins. Four isoforms of Numb are expressed in vertebrates, two of which selectively associate with the cortical membrane. In this study, we have characterized a cortical pool of Numb that colocalizes with AP2 and Eps15 at substratum plasma membrane punctae and cortical membrane-associated vesicles. Green fluorescent protein (GFP)-tagged mutants of Numb were used to identify the structural determinants required for localization. In addition to the previously described association of the PTB domain with the plasma membrane, we show that the AP2-binding motifs facilitate the association of Numb with cortical membrane punctae and vesicles. We also show that agonist stimulation of G protein-coupled receptors (GPCRs) that are linked to phospholipase Cbeta and protein kinase C (PKC) activation causes redistribution of Numb from the cortical membrane to the cytosol. This effect is correlated with Numb phosphorylation and an increase in its Triton X-100 solubility. Live-imaging analysis of mutants identified two regions within Numb that are independently responsive to GPCR-mediated lipid hydrolysis and PKC activation: the PTB domain and a region encompassing at least three putative PKC phosphorylation sites. Our data indicate that membrane localization of Numb is dynamically regulated by GPCR-activated phospholipid hydrolysis and PKC-dependent phosphorylation events.
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Affiliation(s)
- Sascha E. Dho
- *The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
| | - JoAnn Trejo
- Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7365
| | - David P. Siderovski
- Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7365
| | - C. Jane McGlade
- *The Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5S 2E4, Canada; and
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22
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Pugacheva EN, Golemis EA. HEF1-aurora A interactions: points of dialog between the cell cycle and cell attachment signaling networks. Cell Cycle 2006; 5:384-91. [PMID: 16479169 PMCID: PMC2547350 DOI: 10.4161/cc.5.4.2439] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Regulated timing of cell division cycles, and geometrical precision in the planar orientation of cell division, are critical during organismal development and remain important for the maintenance of polarized structures in adults. Mounting evidence suggests that these processes are coordinated at the centrosome through the action of proteins that mediate both cell cycle and cell attachment. Our recent work identifying HEF1 as an activator of the Aurora A kinase suggests a novel hub for such integrated signaling. We suggest that defects in components of the machinery specifying the temporal and spatial integration of cell division may induce cancer and other diseases through pleiotropic effects on cell migration, proliferation, apoptosis, and genomic stability.
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Affiliation(s)
- Elena N. Pugacheva
- Division of Basic Science, Fox Chase Cancer Center, 333 Cottman Ave., Philadelphia, PA 19111
| | - Erica A. Golemis
- Division of Basic Science, Fox Chase Cancer Center, 333 Cottman Ave., Philadelphia, PA 19111
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23
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David NB, Martin CA, Segalen M, Rosenfeld F, Schweisguth F, Bellaïche Y. Drosophila Ric-8 regulates Galphai cortical localization to promote Galphai-dependent planar orientation of the mitotic spindle during asymmetric cell division. Nat Cell Biol 2006; 7:1083-90. [PMID: 16228010 DOI: 10.1038/ncb1319] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2005] [Accepted: 09/22/2005] [Indexed: 11/08/2022]
Abstract
Localization and activation of heterotrimeric G proteins have a crucial role during asymmetric cell division. The asymmetric division of the Drosophila sensory precursor cell (pl) is polarized along the antero-posterior axis by Frizzled signalling and, during this division, activation of Galphai depends on Partner of Inscuteable (Pins). We establish here that Ric-8, which belongs to a family of guanine nucleotide-exchange factors for Galphai, regulates cortical localization of the subunits Galphai and Gbeta13F. Ric-8, Galphai and Pins are not necessary for the control of the anteroposterior orientation of the mitotic spindle during pl cell division downstream of Frizzled signalling, but they are required for maintainance of the spindle within the plane of the epithelium. On the contrary, Frizzled signalling orients the spindle along the antero-posterior axis but also tilts it along the apico-basal axis. Thus, Frizzled and heterotrimeric G-protein signalling act in opposition to ensure that the spindle aligns both in the plane of the epithelium and along the tissue polarity axis.
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Affiliation(s)
- Nicolas B David
- Institute Curie, CNRS UMR 144, 26 rue d'Ulm, Paris 75248, France.
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24
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Emery G, Hutterer A, Berdnik D, Mayer B, Wirtz-Peitz F, Gaitan MG, Knoblich JA. Asymmetric Rab 11 endosomes regulate delta recycling and specify cell fate in the Drosophila nervous system. Cell 2005; 122:763-73. [PMID: 16137758 DOI: 10.1016/j.cell.2005.08.017] [Citation(s) in RCA: 250] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2005] [Revised: 06/22/2005] [Accepted: 08/16/2005] [Indexed: 01/15/2023]
Abstract
Drosophila sensory organ precursor (SOP) cells are a well-studied model system for asymmetric cell division. During SOP division, the determinants Numb and Neuralized segregate into the pIIb daughter cell and establish a distinct cell fate by regulating Notch/Delta signaling. Here, we describe a Numb- and Neuralized-independent mechanism that acts redundantly in cell-fate specification. We show that trafficking of the Notch ligand Delta is different in the two daughter cells. In pIIb, Delta passes through the recycling endosome which is marked by Rab 11. In pIIa, however, the recycling endosome does not form because the centrosome fails to recruit Nuclear fallout, a Rab 11 binding partner that is essential for recycling endosome formation. Using a mammalian cell culture system, we demonstrate that recycling endosomes are essential for Delta activity. Our results suggest that cells can regulate signaling pathways and influence their developmental fate by inhibiting the formation of individual endocytic compartments.
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Affiliation(s)
- Gregory Emery
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Dr. Bohr Gasse 3-5, 1030 Vienna, Austria
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25
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Langevin J, Le Borgne R, Rosenfeld F, Gho M, Schweisguth F, Bellaïche Y. Lethal Giant Larvae Controls the Localization of Notch-Signaling Regulators Numb, Neuralized, and Sanpodo in Drosophila Sensory-Organ Precursor Cells. Curr Biol 2005; 15:955-62. [PMID: 15916953 DOI: 10.1016/j.cub.2005.04.054] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2005] [Revised: 04/18/2005] [Accepted: 04/18/2005] [Indexed: 11/21/2022]
Abstract
Asymmetric distribution of fate determinants is a fundamental mechanism underlying the acquisition of distinct cell fates during asymmetric division. In Drosophila neuroblasts, the apical DmPar6/DaPKC complex inhibits Lethal giant larvae (Lgl) to promote the basal localization of fate determinants. In contrast, in the sensory precursor (pI) cells that divide asymmetrically with a planar polarity, Lgl inhibits Notch signaling in the anterior pI daughter cell, pIIb, by a yet-unknown mechanism. We show here that Lgl promotes the cortical recruitment of Partner of Numb (Pon) and regulates the asymmetric distribution of the fate determinants Numb and Neuralized during the pI cell division. Analysis of Pon-GFP and Histone2B-mRFP distribution in two-color movies confirmed that Lgl regulates Pon localization. Moreover, posterior DaPKC restricts Lgl function to the anterior cortex at mitosis. Thus, Lgl functions similarly in neuroblasts and in pI cells. We also show that Lgl promotes the acquisition of the pIIb cell fate by inhibiting the plasma membrane localization of Sanpodo and thereby preventing the activation of Notch signaling in the anterior pI daughter cell. Thus, Lgl regulates cell fate by controlling Pon cortical localization, asymmetric localization of Numb and Neuralized, and plasma-membrane localization of Sandopo.
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Affiliation(s)
- Johanna Langevin
- Institut Curie, Unité mixte de recherche 144, 26 rue d'Ulm, 75248 Paris cedex 05, France
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26
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27
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Betschinger J, Knoblich JA. Dare to be different: asymmetric cell division in Drosophila, C. elegans and vertebrates. Curr Biol 2004; 14:R674-85. [PMID: 15324689 DOI: 10.1016/j.cub.2004.08.017] [Citation(s) in RCA: 321] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
One widespread mechanism for the generation of diverse cell types is the unequal inheritance of cell fate determinants. Several such determinants have been identified in the fruitfly Drosophila melanogaster and the worm Caenorhabditis elegans and the molecular machinery responsible for their asymmetric segregation is beginning to be unraveled. To divide asymmetrically, cells establish an axis of polarity, orient the mitotic spindle along this axis and localize cell fate determinants to one side of the cell. During cytokinesis, determinants are then segregated into one of the two daughter cells where they direct cell fate. Here, we outline the steps and factors that are involved in this process in Drosophila and C. elegans and discuss their potential conservation in vertebrates.
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Affiliation(s)
- Jörg Betschinger
- Research Institute of Molecular Pathology, Dr. Bohr Gasse 7, 1030 Vienna, Austria.
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28
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Faubert A, Lessard J, Sauvageau G. Are genetic determinants of asymmetric stem cell division active in hematopoietic stem cells? Oncogene 2004; 23:7247-55. [PMID: 15378084 DOI: 10.1038/sj.onc.1207944] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Stem cells have acquired a golden glow in the past few years as they represent possible tools for reversing the damage wreak on organs. These cells are found not only in major regenerative tissues, such as the epithelia, blood and testes, but also in 'static tissues', such as the nervous system and liver, where they play a central role in tissue growth and maintenance. The mechanism by which stem cells maintain populations of highly differentiated, short-lived cells seems to involve a critical balance between alternate fates: daughter cells either maintain stem cell identity or initiate differentiation. Recent studies in lower organisms have unveiled the regulatory mechanisms of asymmetric stem cell divisions. In these models, the surrounding environment likely provides key instructive signals for the cells to choose one fate over another. Our understanding now extends to the intrinsic mechanisms of cell polarity that influence asymmetrical stem cell divisions. This article focuses on the genetic determinants of asymmetric stem cell divisions in lower organisms as a model for studying the process of self-renewal of mammalian hematopoietic stem cells.
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Affiliation(s)
- Amélie Faubert
- Laboratory of Molecular Genetics of Hematopoietic Stem Cells, Institute of Research in Immunology and Cancer, University of Montreal, Quebec, Canada
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29
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Moore AW, Roegiers F, Jan LY, Jan YN. Conversion of neurons and glia to external-cell fates in the external sensory organs of Drosophila hamlet mutants by a cousin-cousin cell-type respecification. Genes Dev 2004; 18:623-8. [PMID: 15075290 PMCID: PMC387238 DOI: 10.1101/gad.1170904] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The Drosophila external sensory organ forms in a lineage elaborating from a single precursor cell via a stereotypical series of asymmetric divisions. HAMLET transcription factor expression demarcates the lineage branch that generates two internal cell types, the external sensory neuron and thecogen. In HAMLET mutant organs, these internal cells are converted to external cells via an unprecedented cousin-cousin cell-fate respecification event. Conversely, ectopic HAMLET expression in the external cell branch leads to internal cell production. The fate-determining signals NOTCH and PAX2 act at multiple stages of lineage elaboration and HAMLET acts to modulate their activity in a branch-specific manner.
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Affiliation(s)
- Adrian W Moore
- Howard Hughes Medical Institute, Department of Physiology, University of California at San Francisco, CA 94143, USA
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30
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Zallen JA, Wieschaus E. Patterned gene expression directs bipolar planar polarity in Drosophila. Dev Cell 2004; 6:343-55. [PMID: 15030758 DOI: 10.1016/s1534-5807(04)00060-7] [Citation(s) in RCA: 397] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2003] [Revised: 01/07/2004] [Accepted: 01/09/2004] [Indexed: 01/23/2023]
Abstract
During convergent extension in Drosophila, polarized cell movements cause the germband to narrow along the dorsal-ventral (D-V) axis and more than double in length along the anterior-posterior (A-P) axis. This tissue remodeling requires the correct patterning of gene expression along the A-P axis, perpendicular to the direction of cell movement. Here, we demonstrate that A-P patterning information results in the polarized localization of cortical proteins in intercalating cells. In particular, cell fate differences conferred by striped expression of the even-skipped and runt pair-rule genes are both necessary and sufficient to orient planar polarity. This polarity consists of an enrichment of nonmuscle myosin II at A-P cell borders and Bazooka/PAR-3 protein at the reciprocal D-V cell borders. Moreover, bazooka mutants are defective for germband extension. These results indicate that spatial patterns of gene expression coordinate planar polarity across a multicellular population through the localized distribution of proteins required for cell movement.
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Affiliation(s)
- Jennifer A Zallen
- Department of Molecular Biology, Princeton University, Lewis Thomas Lab, Washington Road, Princeton, NJ 08544, USA.
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31
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Abstract
Asymmetric cell division is a conserved mechanism for partitioning information during mitosis. Over the past several years, significant progress has been made in our understanding of how cells establish polarity during asymmetric cell division and how determinants, in the form of localized proteins and mRNAs, are segregated. In particular, genetic studies in Drosophila and Caenorhabditis elegans have linked cell polarity, G protein signaling and regulation of the cytoskeleton to coordination of mitotic spindle orientation and localization of determinants. Also, several new studies have furthered our understanding of how asymmetrically localized cell fate determinants, such as the Numb, a negative regulator Notch signaling, functions in biasing cell fates in the developing nervous system in Drosophila. In vertebrates, analysis of dividing neural progenitor cells by in vivo imaging has raised questions about the role of asymmetric cell divisions during neurogenesis.
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Affiliation(s)
- Fabrice Roegiers
- Departments of Physiology and Biochemistry, Howard Hughes Medical Institute, University of California, San Francisco, 533 Parnassus Ave, San Francisco, California, 94122, USA
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32
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Abstract
The majority of cells that build the nervous system of animals are generated early in embryonic development in a process called neurogenesis. Although the vertebrate nervous system is much more complex than that of insects, the underlying principles of neurogenesis are intriguingly similar. In both cases, neuronal cells are derived from polarized progenitor cells that divide asymmetrically. One daughter cell will continue to divide and the other daughter cell leaves the cell cycle and starts to differentiate as a neuron or a glia cell. In Drosophila, this process has been analyzed in great detail and several of the key players that control asymmetric cell division in the developing nervous system have been identified over the past years. Asymmetric cell division in vertebrate neurogenesis has been studied mostly at a descriptive level and so far little is known about the molecular mechanisms that control this process. In this review we will focus on recent findings dealing with asymmetric cell division during neurogenesis in Drosophila and vertebrates and will discuss common principles and apparent differences between both systems.
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Affiliation(s)
- Andreas Wodarz
- Institut für Genetik, Heinrich-Heine-Universität Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany.
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Justice N, Roegiers F, Jan LY, Jan YN. Lethal giant larvae acts together with numb in notch inhibition and cell fate specification in the Drosophila adult sensory organ precursor lineage. Curr Biol 2003; 13:778-83. [PMID: 12725738 DOI: 10.1016/s0960-9822(03)00288-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The tumor suppressor genes lethal giant larvae (lgl) and discs large (dlg) act together to maintain the apical basal polarity of epithelial cells in the Drosophila embryo. Neuroblasts that delaminate from the embryonic epithelium require lgl to promote formation of a basal Numb and Prospero crescent, which will be asymmetrically segregated to the basal daughter cell upon division to specify cell fate. Sensory organ precursors (SOPs) also segregate Numb asymmetrically at cell division. Numb functions to inhibit Notch signaling and to specify the fates of progenies of the SOP that constitute the cellular components of the adult sensory organ. We report here that, in contrast to the embryonic neuroblast, lgl is not required for asymmetric localization of Numb in the dividing SOP. Nevertheless, mosaic analysis reveals that lgl is required for cell fate specification within the SOP lineage; SOPs lacking Lgl fail to specify internal neurons and glia. Epistasis studies suggest that Lgl acts to inhibit Notch signaling by functioning downstream or in parallel with Numb. These findings uncover a previously unknown function of Lgl in the inhibition of Notch and reveal different modes of action by which Lgl can influence cell fate in the neuroblast and SOP lineages.
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Affiliation(s)
- Nicholas Justice
- Department of Physiology, Howard Hughes Medical Institute, University of California, San Francisco, 533 Parnassus Avenue, San Francisco, CA 94143-0725, USA
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34
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Caldwell JC, Eberl DF. Towards a molecular understanding of Drosophila hearing. JOURNAL OF NEUROBIOLOGY 2002; 53:172-89. [PMID: 12382274 PMCID: PMC1805767 DOI: 10.1002/neu.10126] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The Drosophila auditory system is presented as a powerful new genetic model system for understanding the molecular aspects of development and physiology of hearing organs. The fly's ear resides in the antenna, with Johnston's organ serving as the mechanoreceptor. New approaches using electrophysiology and laser vibrometry have provided useful tools to apply to the study of mutations that disrupt hearing. The fundamental developmental processes that generate the peripheral nervous system are fairly well understood, although specific variations of these processes for chordotonal organs (CHO) and especially for Johnston's organ require more scrutiny. In contrast, even the fundamental physiologic workings of mechanosensitive systems are still poorly understood, but rapid recent progress is beginning to shed light. The identification and analysis of mutations that affect auditory function are summarized here, and prospects for the role of the Drosophila auditory system in understanding both insect and vertebrate hearing are discussed.
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Affiliation(s)
- Jason C Caldwell
- Department of Biological Sciences, The University of Iowa, Iowa City, Iowa, 52242-1324, USA
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35
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Abstract
Asymmetric division is a fundamental mechanism for generating cellular diversity. Studies on Drosophila neural progenitors have provided valuable insight into how evolutionarily conserved protein cassettes may be differentially deployed in different developmental contexts to mediate asymmetric divisions. Recent findings also suggest possible mechanisms by which the processes of cell-cycle progression, neuronal lineage development and asymmetric divisions may be integrated.
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Affiliation(s)
- William Chia
- MRC Centre for Developmental Neurobiology, King's College London, 4th Floor, New Hunts House, Guy's Hospital Campus, London, UK.
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36
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Rath P, Lin S, Udolph G, Cai Y, Yang X, Chia W. Inscuteable-independent apicobasally oriented asymmetric divisions in the Drosophila embryonic CNS. EMBO Rep 2002; 3:660-5. [PMID: 12101099 PMCID: PMC1084188 DOI: 10.1093/embo-reports/kvf134] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Inscuteable is the founding member of a protein complex localised to the apical cortex of Drosophila neural progenitors that controls their asymmetric division. Aspects of asymmetric divisions of all identified apicobasally oriented neural progenitors characterised to date, in both the central and peripheral nervous systems, require inscuteable. Here we examine the generality of this requirement. We show that many identified neuroblast lineages, in fact, do not require inscuteable for normal morphological development. To elucidate the requirements for apicobasal asymmetric divisions in a context where inscuteable is not essential, we focused on the MP2 > dMP2 + vMP2 division. We show that for MP2 divisions, asymmetric localisation and segregation of Numb and the specification of distinct dMP2 and vMP2 identities require bazooka but not inscuteable. We conclude that inscuteable is not required for all apicobasally oriented asymmetric divisions and that, in some cellular contexts, bazooka can mediate apicobasal asymmetric divisions without inscuteable.
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Affiliation(s)
- Priyadarshini Rath
- Developmental Neurobiology Laboratory, Institute of Molecular and Cell Biology, Sinagapore, UK
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