1
|
Verma D, Singh A, Singh J, Mutsuddi M, Mukherjee A. Regulation of Notch signaling by non-muscle myosin II Zipper in Drosophila. Cell Mol Life Sci 2024; 81:195. [PMID: 38653877 PMCID: PMC11039529 DOI: 10.1007/s00018-024-05142-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 12/27/2023] [Accepted: 01/23/2024] [Indexed: 04/25/2024]
Abstract
The Notch pathway is an evolutionarily conserved signaling system that is intricately regulated at multiple levels and it influences different aspects of development. In an effort to identify novel components involved in Notch signaling and its regulation, we carried out protein interaction screens which identified non-muscle myosin II Zipper (Zip) as an interacting partner of Notch. Physical interaction between Notch and Zip was further validated by co-immunoprecipitation studies. Immunocytochemical analyses revealed that Notch and Zip co-localize within same cytoplasmic compartment. Different alleles of zip also showed strong genetic interactions with Notch pathway components. Downregulation of Zip resulted in wing phenotypes that were reminiscent of Notch loss-of-function phenotypes and a perturbed expression of Notch downstream targets, Cut and Deadpan. Further, synergistic interaction between Notch and Zip resulted in highly ectopic expression of these Notch targets. Activated Notch-induced tumorous phenotype of larval tissues was enhanced by over-expression of Zip. Notch-Zip synergy resulted in the activation of JNK pathway that consequently lead to MMP activation and proliferation. Taken together, our results suggest that Zip may play an important role in regulation of Notch signaling.
Collapse
Affiliation(s)
- Dipti Verma
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, 221005, India
| | - Ankita Singh
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, 221005, India
| | - Jyoti Singh
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, 221005, India
| | - Mousumi Mutsuddi
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, 221005, India
| | - Ashim Mukherjee
- Department of Molecular and Human Genetics, Institute of Science, Banaras Hindu University, Varanasi, Uttar Pradesh, 221005, India.
| |
Collapse
|
2
|
Bhattacharya M, Starz-Gaiano M. Steroid hormone signaling synchronizes cell migration machinery, adhesion and polarity to direct collective movement. J Cell Sci 2024; 137:jcs261164. [PMID: 38323986 DOI: 10.1242/jcs.261164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 01/23/2024] [Indexed: 02/08/2024] Open
Abstract
Migratory cells - either individually or in cohesive groups - are critical for spatiotemporally regulated processes such as embryonic development and wound healing. Their dysregulation is the underlying cause of formidable health problems such as congenital abnormalities and metastatic cancers. Border cell behavior during Drosophila oogenesis provides an effective model to study temporally regulated, collective cell migration in vivo. Developmental timing in flies is primarily controlled by the steroid hormone ecdysone, which acts through a well-conserved, nuclear hormone receptor complex. Ecdysone signaling determines the timing of border cell migration, but the molecular mechanisms governing this remain obscure. We found that border cell clusters expressing a dominant-negative form of ecdysone receptor extended ineffective protrusions. Additionally, these clusters had aberrant spatial distributions of E-cadherin (E-cad), apical domain markers and activated myosin that did not overlap. Remediating their expression or activity individually in clusters mutant for ecdysone signaling did not restore proper migration. We propose that ecdysone signaling synchronizes the functional distribution of E-cadherin, atypical protein kinase C (aPKC), Discs large (Dlg1) and activated myosin post-transcriptionally to coordinate adhesion, polarity and contractility and temporally control collective cell migration.
Collapse
Affiliation(s)
- Mallika Bhattacharya
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - Michelle Starz-Gaiano
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| |
Collapse
|
3
|
Goldner AN, Fessehaye SM, Rodriguez N, Mapes KA, Osterfield M, Doubrovinski K. Evidence that tissue recoil in the early Drosophila embryo is a passive not active process. Mol Biol Cell 2023; 34:br16. [PMID: 37405768 PMCID: PMC10551697 DOI: 10.1091/mbc.e22-09-0409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 06/26/2023] [Accepted: 06/28/2023] [Indexed: 07/06/2023] Open
Abstract
Understanding tissue morphogenesis is impossible without knowing the mechanical properties of the tissue being shaped. Although techniques for measuring tissue material properties are continually being developed, methods for determining how individual proteins contribute to mechanical properties are very limited. Here, we developed two complementary techniques for the acute inactivation of spaghetti squash (the Drosophila myosin regulatory light chain), one based on the recently introduced (auxin-inducible degron 2 (AID2) system, and the other based on a novel method for conditional protein aggregation that results in nearly instantaneous protein inactivation. Combining these techniques with rheological measurements, we show that passive material properties of the cellularization-stage Drosophila embryo are essentially unaffected by myosin activity. These results suggest that this tissue is elastic, not predominantly viscous, on the developmentally relevant timescale.
Collapse
Affiliation(s)
- Amanda Nicole Goldner
- Department of Biophysics and Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Salena M. Fessehaye
- Department of Biophysics and Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Nataly Rodriguez
- Department of Biophysics and Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Kelly Ann Mapes
- Department of Biophysics and Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Miriam Osterfield
- Department of Biophysics and Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Konstantin Doubrovinski
- Department of Biophysics and Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| |
Collapse
|
4
|
High-Content RNAi Phenotypic Screening Unveils the Involvement of Human Ubiquitin-Related Enzymes in Late Cytokinesis. Cells 2022; 11:cells11233862. [PMID: 36497121 PMCID: PMC9737832 DOI: 10.3390/cells11233862] [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: 10/30/2022] [Revised: 11/18/2022] [Accepted: 11/24/2022] [Indexed: 12/04/2022] Open
Abstract
CEP55 is a central regulator of late cytokinesis and is overexpressed in numerous cancers. Its post-translationally controlled recruitment to the midbody is crucial to the structural coordination of the abscission sequence. Our recent evidence that CEP55 contains two ubiquitin-binding domains was the first structural and functional link between ubiquitin signaling and ESCRT-mediated severing of the intercellular bridge. So far, high-content screens focusing on cytokinesis have used multinucleation as the endpoint readout. Here, we report an automated image-based detection method of intercellular bridges, which we applied to further our understanding of late cytokinetic signaling by performing an RNAi screen of ubiquitin ligases and deubiquitinases. A secondary validation confirmed four candidate genes, i.e., LNX2, NEURL, UCHL1 and RNF157, whose downregulation variably affects interconnected phenotypes related to CEP55 and its UBDs, as follows: decreased recruitment of CEP55 to the midbody, increased number of midbody remnants per cell, and increased frequency of intercellular bridges or multinucleation events. This brings into question the Notch-dependent or independent contributions of LNX2 and NEURL proteins to late cytokinesis. Similarly, the role of UCHL1 in autophagy could link its function with the fate of midbody remnants. Beyond the biological interest, this high-content screening approach could also be used to isolate anticancer drugs that act by impairing cytokinesis and CEP55 functions.
Collapse
|
5
|
Kunduri G, Le SH, Baena V, Vijaykrishna N, Harned A, Nagashima K, Blankenberg D, Yoshihiro I, Narayan K, Bamba T, Acharya U, Acharya JK. Delivery of ceramide phosphoethanolamine lipids to the cleavage furrow through the endocytic pathway is essential for male meiotic cytokinesis. PLoS Biol 2022; 20:e3001599. [PMID: 36170207 PMCID: PMC9550178 DOI: 10.1371/journal.pbio.3001599] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 10/10/2022] [Accepted: 08/02/2022] [Indexed: 11/18/2022] Open
Abstract
Cell division, wherein 1 cell divides into 2 daughter cells, is fundamental to all living organisms. Cytokinesis, the final step in cell division, begins with the formation of an actomyosin contractile ring, positioned midway between the segregated chromosomes. Constriction of the ring with concomitant membrane deposition in a specified spatiotemporal manner generates a cleavage furrow that physically separates the cytoplasm. Unique lipids with specific biophysical properties have been shown to localize to intercellular bridges (also called midbody) connecting the 2 dividing cells; however, their biological roles and delivery mechanisms remain largely unknown. In this study, we show that ceramide phosphoethanolamine (CPE), the structural analog of sphingomyelin, has unique acyl chain anchors in Drosophila spermatocytes and is essential for meiotic cytokinesis. The head group of CPE is also important for spermatogenesis. We find that aberrant central spindle and contractile ring behavior but not mislocalization of phosphatidylinositol phosphates (PIPs) at the plasma membrane is responsible for the male meiotic cytokinesis defect in CPE-deficient animals. Further, we demonstrate the enrichment of CPE in multivesicular bodies marked by Rab7, which in turn localize to cleavage furrow. Volume electron microscopy analysis using correlative light and focused ion beam scanning electron microscopy shows that CPE-enriched Rab7 positive endosomes are juxtaposed on contractile ring material. Correlative light and transmission electron microscopy reveal Rab7 positive endosomes as a multivesicular body-like organelle that releases its intraluminal vesicles in the vicinity of ingressing furrows. Genetic ablation of Rab7 or Rab35 or expression of dominant negative Rab11 results in significant meiotic cytokinesis defects. Further, we show that Rab11 function is required for localization of CPE positive endosomes to the cleavage furrow. Our results imply that endosomal delivery of CPE to ingressing membranes is crucial for meiotic cytokinesis.
Collapse
Affiliation(s)
- Govind Kunduri
- Cancer and Developmental Biology Laboratory, National Cancer Institute, Frederick, Maryland, United States of America
| | - Si-Hung Le
- Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Valentina Baena
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Nagampalli Vijaykrishna
- Genomic Medicine Institute and Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Adam Harned
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Kunio Nagashima
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Daniel Blankenberg
- Genomic Medicine Institute and Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
| | - Izumi Yoshihiro
- Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Kedar Narayan
- Center for Molecular Microscopy, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Takeshi Bamba
- Division of Metabolomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Usha Acharya
- Cancer and Developmental Biology Laboratory, National Cancer Institute, Frederick, Maryland, United States of America
| | - Jairaj K. Acharya
- Cancer and Developmental Biology Laboratory, National Cancer Institute, Frederick, Maryland, United States of America
| |
Collapse
|
6
|
Malin J, Rosa Birriel C, Astigarraga S, Treisman JE, Hatini V. Sidekick dynamically rebalances contractile and protrusive forces to control tissue morphogenesis. J Cell Biol 2022; 221:e202107035. [PMID: 35258563 PMCID: PMC8908789 DOI: 10.1083/jcb.202107035] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 12/28/2021] [Accepted: 02/07/2022] [Indexed: 12/19/2022] Open
Abstract
Contractile actomyosin and protrusive branched F-actin networks interact in a dynamic balance, repeatedly contracting and expanding apical cell contacts to organize the epithelium of the developing fly retina. Previously we showed that the immunoglobulin superfamily protein Sidekick (Sdk) contributes to contraction by recruiting the actin binding protein Polychaetoid (Pyd) to vertices. Here we show that as tension increases during contraction, Sdk progressively accumulates at vertices, where it toggles to recruit the WAVE regulatory complex (WRC) to promote actin branching and protrusion. Sdk alternately interacts with the WRC and Pyd using the same C-terminal motif. With increasing protrusion, levels of Sdk and the WRC decrease at vertices while levels of Pyd increase paving the way for another round of contraction. Thus, by virtue of dynamic association with vertices and interchangeable associations with contractile and protrusive effectors, Sdk is central to controlling the balance between contraction and expansion that shapes this epithelium.
Collapse
Affiliation(s)
- Jacob Malin
- Department of Developmental, Molecular & Chemical Biology, Program in Cell, Molecular and Developmental Biology and Program in Genetics, Tufts University School of Medicine, Boston, MA
| | - Christian Rosa Birriel
- Department of Developmental, Molecular & Chemical Biology, Program in Cell, Molecular and Developmental Biology and Program in Genetics, Tufts University School of Medicine, Boston, MA
| | - Sergio Astigarraga
- Skirball Institute for Biomolecular Medicine, New York, NY
- Department of Cell Biology, New York University School of Medicine, New York, NY
| | - Jessica E. Treisman
- Skirball Institute for Biomolecular Medicine, New York, NY
- Department of Cell Biology, New York University School of Medicine, New York, NY
| | - Victor Hatini
- Department of Developmental, Molecular & Chemical Biology, Program in Cell, Molecular and Developmental Biology and Program in Genetics, Tufts University School of Medicine, Boston, MA
| |
Collapse
|
7
|
Gemble S, Wardenaar R, Keuper K, Srivastava N, Nano M, Macé AS, Tijhuis AE, Bernhard SV, Spierings DCJ, Simon A, Goundiam O, Hochegger H, Piel M, Foijer F, Storchová Z, Basto R. Genetic instability from a single S phase after whole-genome duplication. Nature 2022; 604:146-151. [PMID: 35355016 PMCID: PMC8986533 DOI: 10.1038/s41586-022-04578-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 02/23/2022] [Indexed: 12/23/2022]
Abstract
Diploid and stable karyotypes are associated with health and fitness in animals. By contrast, whole-genome duplications—doublings of the entire complement of chromosomes—are linked to genetic instability and frequently found in human cancers1–3. It has been established that whole-genome duplications fuel chromosome instability through abnormal mitosis4–8; however, the immediate consequences of tetraploidy in the first interphase are not known. This is a key question because single whole-genome duplication events such as cytokinesis failure can promote tumorigenesis9 and DNA double-strand breaks10. Here we find that human cells undergo high rates of DNA damage during DNA replication in the first S phase following induction of tetraploidy. Using DNA combing and single-cell sequencing, we show that DNA replication dynamics is perturbed, generating under- and over-replicated regions. Mechanistically, we find that these defects result from a shortage of proteins during the G1/S transition, which impairs the fidelity of DNA replication. This work shows that within a single interphase, unscheduled tetraploid cells can acquire highly abnormal karyotypes. These findings provide an explanation for the genetic instability landscape that favours tumorigenesis after tetraploidization. Extensive DNA damage occurs during the first interphase following induction of tetraploidy in human cells, largely as a result of the lower amount of protein relative to DNA.
Collapse
Affiliation(s)
- Simon Gemble
- Institut Curie, PSL Research University, CNRS, UMR144, Biology of Centrosomes and Genetic Instability Laboratory, Paris, France.
| | - René Wardenaar
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Kristina Keuper
- Department of Molecular Genetics, TU Kaiserslautern, Kaiserslautern, Germany
| | - Nishit Srivastava
- Institut Curie and Institut Pierre Gilles de Gennes, PSL Research University, CNRS, UMR 144, Systems Biology of Cell Polarity and Cell Division, Paris, France
| | - Maddalena Nano
- Institut Curie, PSL Research University, CNRS, UMR144, Biology of Centrosomes and Genetic Instability Laboratory, Paris, France.,Molecular, Cellular, and Developmental Biology Department, University of California, Santa Barbara, CA, USA
| | - Anne-Sophie Macé
- Cell and Tissue Imaging Facility (PICT-IBiSA), Institut Curie, PSL Research University, Centre National de la Recherche Scientifique, Paris, France
| | - Andréa E Tijhuis
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | | | - Diana C J Spierings
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Anthony Simon
- Institut Curie, PSL Research University, CNRS, UMR144, Biology of Centrosomes and Genetic Instability Laboratory, Paris, France
| | - Oumou Goundiam
- Institut Curie, PSL Research University, CNRS, UMR144, Biology of Centrosomes and Genetic Instability Laboratory, Paris, France
| | - Helfrid Hochegger
- Genome Damage and Stability Centre, School of Life Sciences, University of Sussex, Brighton, UK
| | - Matthieu Piel
- Institut Curie and Institut Pierre Gilles de Gennes, PSL Research University, CNRS, UMR 144, Systems Biology of Cell Polarity and Cell Division, Paris, France
| | - Floris Foijer
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Zuzana Storchová
- Department of Molecular Genetics, TU Kaiserslautern, Kaiserslautern, Germany
| | - Renata Basto
- Institut Curie, PSL Research University, CNRS, UMR144, Biology of Centrosomes and Genetic Instability Laboratory, Paris, France.
| |
Collapse
|
8
|
Imran Alsous J, Romeo N, Jackson JA, Mason FM, Dunkel J, Martin AC. Dynamics of hydraulic and contractile wave-mediated fluid transport during Drosophila oogenesis. Proc Natl Acad Sci U S A 2021; 118:e2019749118. [PMID: 33658367 PMCID: PMC7958293 DOI: 10.1073/pnas.2019749118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
From insects to mice, oocytes develop within cysts alongside nurse-like sister germ cells. Prior to fertilization, the nurse cells' cytoplasmic contents are transported into the oocyte, which grows as its sister cells regress and die. Although critical for fertility, the biological and physical mechanisms underlying this transport process are poorly understood. Here, we combined live imaging of germline cysts, genetic perturbations, and mathematical modeling to investigate the dynamics and mechanisms that enable directional and complete cytoplasmic transport in Drosophila melanogaster egg chambers. We discovered that during "nurse cell (NC) dumping" most cytoplasm is transported into the oocyte independently of changes in myosin-II contractility, with dynamics instead explained by an effective Young-Laplace law, suggesting hydraulic transport induced by baseline cell-surface tension. A minimal flow-network model inspired by the famous two-balloon experiment and motivated by genetic analysis of a myosin mutant correctly predicts the directionality, intercellular pattern, and time scale of transport. Long thought to trigger transport through "squeezing," changes in actomyosin contractility are required only once NC volume has become comparable to nuclear volume, in the form of surface contractile waves that drive NC dumping to completion. Our work thus demonstrates how biological and physical mechanisms cooperate to enable a critical developmental process that, until now, was thought to be mainly biochemically regulated.
Collapse
Affiliation(s)
- Jasmin Imran Alsous
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Nicolas Romeo
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Jonathan A Jackson
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
- Graduate Program in Biophysics, Harvard University, Cambridge, MA 02138
| | - Frank M Mason
- Program in Cancer Biology, Vanderbilt University, Nashville, TN 37232
| | - Jörn Dunkel
- Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Adam C Martin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139;
| |
Collapse
|
9
|
Gemble S, Basto R. CHRONOCRISIS: When Cell Cycle Asynchrony Generates DNA Damage in Polyploid Cells. Bioessays 2020; 42:e2000105. [PMID: 32885500 DOI: 10.1002/bies.202000105] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/19/2020] [Indexed: 12/16/2022]
Abstract
Polyploid cells contain multiple copies of all chromosomes. Polyploidization can be developmentally programmed to sustain tissue barrier function or to increase metabolic potential and cell size. Programmed polyploidy is normally associated with terminal differentiation and poor proliferation capacity. Conversely, non-programmed polyploidy can give rise to cells that retain the ability to proliferate. This can fuel rapid genome rearrangements and lead to diseases like cancer. Here, the mechanisms that generate polyploidy are reviewed and the possible challenges upon polyploid cell division are discussed. The discussion is framed around a recent study showing that asynchronous cell cycle progression (an event that is named "chronocrisis") of different nuclei from a polyploid cell can generate DNA damage at mitotic entry. The potential mechanisms explaining how mitosis in non-programmed polyploid cells can generate abnormal karyotypes and genetic instability are highlighted.
Collapse
Affiliation(s)
- Simon Gemble
- Biology of Centrosomes and Genetic Instability Lab, Institut Curie, PSL Research University, CNRS UMR144, 12 rue Lhomond, Paris, 75005, France
| | - Renata Basto
- Biology of Centrosomes and Genetic Instability Lab, Institut Curie, PSL Research University, CNRS UMR144, 12 rue Lhomond, Paris, 75005, France
| |
Collapse
|
10
|
Role of Notch Signaling in Leg Development in Drosophila melanogaster. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1218:103-127. [PMID: 32060874 DOI: 10.1007/978-3-030-34436-8_7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Notch pathway plays diverse and fundamental roles during animal development. One of the most relevant, which arises directly from its unique mode of activation, is the specification of cell fates and tissue boundaries. The development of the leg of Drosophila melanogaster is a fine example of this Notch function, as it is required to specify the fate of the cells that will eventually form the leg joints, the flexible structures that separate the different segments of the adult leg. Notch activity is accurately activated and maintained at the distal end of each segment in response to the proximo-distal patterning gene network of the developing leg. Region-specific downstream targets of Notch in turn regulate the formation of the different types of joints. We discuss recent findings that shed light on the molecular and cellular mechanisms that are ultimately governed by Notch to achieve epithelial fold and joint morphogenesis. Finally, we briefly summarize the role that Notch plays in inducing the nonautonomous growth of the leg. Overall, this book chapter aims to highlight leg development as a useful model to study how patterning information is translated into specific cell behaviors that shape the final form of an adult organ.
Collapse
|
11
|
Nano M, Gemble S, Simon A, Pennetier C, Fraisier V, Marthiens V, Basto R. Cell-Cycle Asynchrony Generates DNA Damage at Mitotic Entry in Polyploid Cells. Curr Biol 2019; 29:3937-3945.e7. [PMID: 31708395 DOI: 10.1016/j.cub.2019.09.041] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 07/29/2019] [Accepted: 09/16/2019] [Indexed: 01/17/2023]
Abstract
Polyploidy arises from the gain of complete chromosome sets [1], and it is known to promote cancer genome evolution. Recent evidence suggests that a large proportion of human tumors experience whole-genome duplications (WGDs), which might favor the generation of highly abnormal karyotypes within a short time frame, rather than in a stepwise manner [2-6]. However, the molecular mechanisms linking whole-genome duplication to genetic instability remain poorly understood. Using repeated cytokinesis failure to induce polyploidization of Drosophila neural stem cells (NSCs) (also called neuroblasts [NBs]), we investigated the consequences of polyploidy in vivo. Surprisingly, we found that DNA damage is generated in a subset of nuclei of polyploid NBs during mitosis. Importantly, our observations in flies were confirmed in mouse NSCs (mNSCs) and human cancer cells after acute cytokinesis inhibition. Interestingly, DNA damage occurs in nuclei that were not ready to enter mitosis but were forced to do so when exposed to the mitotic environment of neighboring nuclei within the same cell. Additionally, we found that polyploid cells are cell-cycle asynchronous and forcing cell-cycle synchronization was sufficient to lower the levels of DNA damage generated during mitosis. Overall, this work supports a model in which DNA damage at mitotic entry can generate DNA structural abnormalities that might contribute to the onset of genetic instability.
Collapse
Affiliation(s)
- Maddalena Nano
- Biology of Centrosomes and Genetic Instability Lab, Institut Curie, PSL Research University, CNRS UMR144, 12 rue Lhomond, 75005 Paris, France.
| | - Simon Gemble
- Biology of Centrosomes and Genetic Instability Lab, Institut Curie, PSL Research University, CNRS UMR144, 12 rue Lhomond, 75005 Paris, France
| | - Anthony Simon
- Biology of Centrosomes and Genetic Instability Lab, Institut Curie, PSL Research University, CNRS UMR144, 12 rue Lhomond, 75005 Paris, France
| | - Carole Pennetier
- Biology of Centrosomes and Genetic Instability Lab, Institut Curie, PSL Research University, CNRS UMR144, 12 rue Lhomond, 75005 Paris, France
| | - Vincent Fraisier
- Plateforme Imagerie PICT-IBiSA, Institut Curie, PSL Research University, CNRS UMR144, 12 rue Lhomond, 75005 Paris, France
| | - Veronique Marthiens
- Biology of Centrosomes and Genetic Instability Lab, Institut Curie, PSL Research University, CNRS UMR144, 12 rue Lhomond, 75005 Paris, France
| | - Renata Basto
- Biology of Centrosomes and Genetic Instability Lab, Institut Curie, PSL Research University, CNRS UMR144, 12 rue Lhomond, 75005 Paris, France.
| |
Collapse
|
12
|
Letizia A, He D, Astigarraga S, Colombelli J, Hatini V, Llimargas M, Treisman JE. Sidekick Is a Key Component of Tricellular Adherens Junctions that Acts to Resolve Cell Rearrangements. Dev Cell 2019; 50:313-326.e5. [PMID: 31353315 DOI: 10.1016/j.devcel.2019.07.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 05/03/2019] [Accepted: 07/02/2019] [Indexed: 11/27/2022]
Abstract
Tricellular adherens junctions are points of high tension that are central to the rearrangement of epithelial cells. However, the molecular composition of these junctions is unknown, making it difficult to assess their role in morphogenesis. Here, we show that Sidekick, an immunoglobulin family cell adhesion protein, is highly enriched at tricellular adherens junctions in Drosophila. This localization is modulated by tension, and Sidekick is itself necessary to maintain normal levels of cell bond tension. Loss of Sidekick causes defects in cell and junctional rearrangements in actively remodeling epithelial tissues like the retina and tracheal system. The adaptor proteins Polychaetoid and Canoe are enriched at tricellular adherens junctions in a Sidekick-dependent manner; Sidekick functionally interacts with both proteins and directly binds to Polychaetoid. We suggest that Polychaetoid and Canoe link Sidekick to the actin cytoskeleton to enable tricellular adherens junctions to maintain or transmit cell bond tension during epithelial cell rearrangements.
Collapse
Affiliation(s)
- Annalisa Letizia
- Institut de Biologia Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Baldiri Reixac, 10-12, Barcelona 08028, Spain
| | - DanQing He
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Cell Biology, NYU School of Medicine, 540 First Avenue, New York, NY 10016, USA
| | - Sergio Astigarraga
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Cell Biology, NYU School of Medicine, 540 First Avenue, New York, NY 10016, USA
| | - Julien Colombelli
- Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Parc Científic de Barcelona, Baldiri Reixac, 10, Barcelona 08028, Spain
| | - Victor Hatini
- Department of Developmental, Molecular & Chemical Biology, Program in Cell, Molecular and Developmental Biology and Program in Genetics, Tufts University School of Medicine, 150 Harrison Avenue, Jaharis 322, Boston, MA 02111, USA
| | - Marta Llimargas
- Institut de Biologia Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Baldiri Reixac, 10-12, Barcelona 08028, Spain.
| | - Jessica E Treisman
- Kimmel Center for Biology and Medicine at the Skirball Institute and Department of Cell Biology, NYU School of Medicine, 540 First Avenue, New York, NY 10016, USA.
| |
Collapse
|
13
|
Structure-function analysis of β-arrestin Kurtz reveals a critical role of receptor interactions in downregulation of GPCR signaling in vivo. Dev Biol 2019; 455:409-419. [PMID: 31325455 DOI: 10.1016/j.ydbio.2019.07.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 06/15/2019] [Accepted: 07/16/2019] [Indexed: 01/14/2023]
Abstract
Arrestins control signaling via the G protein coupled receptors (GPCRs), serving as both signal terminators and transducers. Previous studies identified several structural elements in arrestins that contribute to their functions as GPCR regulators. However, the importance of these elements in vivo is unclear, and the developmental roles of arrestins are not well understood. We carried out an in vivo structure-function analysis of Kurtz (Krz), the single ortholog of mammalian β-arrestins in the Drosophila genome. A combination of Krz mutations affecting the GPCR-phosphosensing and receptor core-binding ("finger loop") functions (Krz-KKVL/A) resulted in a complete loss of Krz activity during development. Endosome recruitment and bioluminescence resonance energy transfer (BRET) assays revealed that the KKVL/A mutations abolished the GPCR-binding ability of Krz. We found that the isolated "finger loop" mutation (Krz-VL/A), while having a negligible effect on GPCR internalization, severely affected Krz function, suggesting that tight receptor interactions are necessary for proper termination of signaling in vivo. Genetic analysis as well as live imaging demonstrated that mutations in Krz led to hyperactivity of the GPCR Mist (also known as Mthl1), which is activated by its ligand Folded gastrulation (Fog) and is responsible for cellular contractility and epithelial morphogenesis. Krz mutations affected two developmental events that are under the control of Fog-Mist signaling: gastrulation and morphogenesis of the wing. Overall, our data reveal the functional importance in vivo of direct β-arrestin/GPCR binding, which is mediated by the recognition of the phosphorylated receptor tail and receptor core interaction. These Krz-GPCR interactions are critical for setting the correct level of Fog-Mist signaling during epithelial morphogenesis.
Collapse
|
14
|
Hunter GL, He L, Perrimon N, Charras G, Giniger E, Baum B. A role for actomyosin contractility in Notch signaling. BMC Biol 2019; 17:12. [PMID: 30744634 PMCID: PMC6369551 DOI: 10.1186/s12915-019-0625-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/04/2019] [Indexed: 12/24/2022] Open
Abstract
Background Notch-Delta signaling functions across a wide array of animal systems to break symmetry in a sheet of undifferentiated cells and generate cells with different fates, a process known as lateral inhibition. Unlike many other signaling systems, however, since both the ligand and receptor are transmembrane proteins, the activation of Notch by Delta depends strictly on cell-cell contact. Furthermore, the binding of the ligand to the receptor may not be sufficient to induce signaling, since recent work in cell culture suggests that ligand-induced Notch signaling also requires a mechanical pulling force. This tension exposes a cleavage site in Notch that, when cut, activates signaling. Although it is not known if mechanical tension contributes to signaling in vivo, others have suggested that this is how endocytosis of the receptor-ligand complex contributes to the cleavage and activation of Notch. In a similar way, since Notch-mediated lateral inhibition at a distance in the dorsal thorax of the pupal fly is mediated via actin-rich protrusions, it is possible that cytoskeletal forces generated by networks of filamentous actin and non-muscle myosin during cycles of protrusion extension and retraction also contribute to Notch signaling. Results To test this hypothesis, we carried out a detailed analysis of the role of myosin II-dependent tension in Notch signaling in the developing fly and in cell culture. Using dynamic fluorescence-based reporters of Notch, we found that myosin II is important for signaling in signal sending and receiving cells in both systems—as expected if myosin II-dependent tension across the Notch-Delta complex contributes to Notch activation. While myosin II was found to contribute most to signaling at a distance, it was also required for maximal signaling between adjacent cells that share lateral contacts and for signaling between cells in culture. Conclusions Together these results reveal a previously unappreciated role for non-muscle myosin II contractility in Notch signaling, providing further support for the idea that force contributes to the cleavage and activation of Notch in the context of ligand-dependent signaling, and a new paradigm for actomyosin-based mechanosensation. Electronic supplementary material The online version of this article (10.1186/s12915-019-0625-9) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Ginger L Hunter
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, 20892, USA. .,MRC-LMCB, University College London, London, WC1E6BT, UK. .,Institute for the Physics of Living Systems, University College London, London, WC1E6BT, UK. .,Present Address: Department of Biology, Clarkson University, Potsdam, NY, 13699, USA.
| | - Li He
- Department of Genetics, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA, 02115, USA
| | - Norbert Perrimon
- Department of Genetics, Harvard Medical School, Howard Hughes Medical Institute, Boston, MA, 02115, USA
| | - Guillaume Charras
- London Centre for Nanotechnology, University College London, London, WC1E6BT, UK.,Department of Cell and Developmental Biology, University College London, London, WC1E6BT, UK
| | - Edward Giniger
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, 20892, USA.
| | - Buzz Baum
- MRC-LMCB, University College London, London, WC1E6BT, UK.,Institute for the Physics of Living Systems, University College London, London, WC1E6BT, UK
| |
Collapse
|
15
|
Blake-Hedges C, Megraw TL. Coordination of Embryogenesis by the Centrosome in Drosophila melanogaster. Results Probl Cell Differ 2019; 67:277-321. [PMID: 31435800 DOI: 10.1007/978-3-030-23173-6_12] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The first 3 h of Drosophila melanogaster embryo development are exemplified by rapid nuclear divisions within a large syncytium, transforming the zygote to the cellular blastoderm after 13 successive cleavage divisions. As the syncytial embryo develops, it relies on centrosomes and cytoskeletal dynamics to transport nuclei, maintain uniform nuclear distribution throughout cleavage cycles, ensure generation of germ cells, and coordinate cellularization. For the sake of this review, we classify six early embryo stages that rely on processes coordinated by the centrosome and its regulation of the cytoskeleton. The first stage features migration of one of the female pronuclei toward the male pronucleus following maturation of the first embryonic centrosomes. Two subsequent stages distribute the nuclei first axially and then radially in the embryo. The remaining three stages involve centrosome-actin dynamics that control cortical plasma membrane morphogenesis. In this review, we highlight the dynamics of the centrosome and its role in controlling the six stages that culminate in the cellularization of the blastoderm embryo.
Collapse
Affiliation(s)
- Caitlyn Blake-Hedges
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, USA.
| | - Timothy L Megraw
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, USA
| |
Collapse
|
16
|
Hall ET, Hoesing E, Sinkovics E, Verheyen EM. Actomyosin contractility modulates Wnt signaling through adherens junction stability. Mol Biol Cell 2018; 30:411-426. [PMID: 30540525 PMCID: PMC6589568 DOI: 10.1091/mbc.e18-06-0345] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Actomyosin contractility can influence the canonical Wnt signaling pathway in processes like mesoderm differentiation and tissue stiffness during tumorigenesis. We identified that increased nonmuscle myosin II activation and cellular contraction inhibited Wnt target gene transcription in developing Drosophila imaginal disks. Genetic interactions studies were used to show that this effect was due to myosin-induced accumulation of cortical F-actin resulting in clustering and accumulation of E-cadherin to the adherens junctions. This results in E-cadherin titrating any available β-catenin, the Wnt pathway transcriptional coactivator, to the adherens junctions in order to maintain cell-cell adhesion under contraction. We show that decreased levels of cytoplasmic β-catenin result in insufficient nuclear translocation for full Wnt target gene transcription. Previous studies have identified some of these interactions, but we present a thorough analysis using the wing disk epithelium to show the consequences of modulating myosin phosphatase. Our work elucidates a mechanism in which the dynamic promotion of actomyosin contractility refines patterning of Wnt transcription during development and maintenance of epithelial tissue in organisms.
Collapse
Affiliation(s)
- Eric T Hall
- Department of Molecular Biology and Biochemistry, Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Elizabeth Hoesing
- Department of Molecular Biology and Biochemistry, Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Endre Sinkovics
- Department of Molecular Biology and Biochemistry, Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Esther M Verheyen
- Department of Molecular Biology and Biochemistry, Centre for Cell Biology, Development and Disease, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| |
Collapse
|
17
|
Grabon A, Bankaitis VA, McDermott MI. The interface between phosphatidylinositol transfer protein function and phosphoinositide signaling in higher eukaryotes. J Lipid Res 2018; 60:242-268. [PMID: 30504233 DOI: 10.1194/jlr.r089730] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/12/2018] [Indexed: 12/22/2022] Open
Abstract
Phosphoinositides are key regulators of a large number of diverse cellular processes that include membrane trafficking, plasma membrane receptor signaling, cell proliferation, and transcription. How a small number of chemically distinct phosphoinositide signals are functionally amplified to exert specific control over such a diverse set of biological outcomes remains incompletely understood. To this end, a novel mechanism is now taking shape, and it involves phosphatidylinositol (PtdIns) transfer proteins (PITPs). The concept that PITPs exert instructive regulation of PtdIns 4-OH kinase activities and thereby channel phosphoinositide production to specific biological outcomes, identifies PITPs as central factors in the diversification of phosphoinositide signaling. There are two evolutionarily distinct families of PITPs: the Sec14-like and the StAR-related lipid transfer domain (START)-like families. Of these two families, the START-like PITPs are the least understood. Herein, we review recent insights into the biochemical, cellular, and physiological function of both PITP families with greater emphasis on the START-like PITPs, and we discuss the underlying mechanisms through which these proteins regulate phosphoinositide signaling and how these actions translate to human health and disease.
Collapse
Affiliation(s)
- Aby Grabon
- E. L. Wehner-Welch Laboratory, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114
| | - Vytas A Bankaitis
- E. L. Wehner-Welch Laboratory, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114
| | - Mark I McDermott
- E. L. Wehner-Welch Laboratory, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114
| |
Collapse
|
18
|
Saatian B, Austin RS, Tian G, Chen C, Nguyen V, Kohalmi SE, Geelen D, Cui Y. Analysis of a novel mutant allele of GSL8 reveals its key roles in cytokinesis and symplastic trafficking in Arabidopsis. BMC PLANT BIOLOGY 2018; 18:295. [PMID: 30466394 PMCID: PMC6249969 DOI: 10.1186/s12870-018-1515-y] [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] [Received: 10/16/2017] [Accepted: 10/31/2018] [Indexed: 05/10/2023]
Abstract
BACKGROUND Plant cell walls are mainly composed of polysaccharides such as cellulose and callose. Callose exists at a very low level in the cell wall; however, it plays critical roles at different stages of plant development as well as in defence against unfavorable conditions. Callose is accumulated at the cell plate, at plasmodesmata and in male and female gametophytes. Despite the important roles of callose in plants, the mechanisms of its synthesis and regulatory properties are not well understood. RESULTS CALLOSE SYNTHASE (CALS) genes, also known as GLUCAN SYNTHASE-LIKE (GSL), comprise a family of 12 members in Arabidopsis thaliana. Here, we describe a new allele of GSL8 (named essp8) that exhibits pleiotropic seedling defects. Reduction of callose deposition at the cell plates and plasmodesmata in essp8 leads to ectopic endomitosis and an increase in the size exclusion limit of plasmodesmata during early seedling development. Movement of two non-cell-autonomous factors, SHORT ROOT and microRNA165/6, both required for root radial patterning during embryonic root development, are dysregulated in the primary root of essp8. This observation provides evidence for a molecular mechanism explaining the gsl8 root phenotype. We demonstrated that GSL8 interacts with PLASMODESMATA-LOCALIZED PROTEIN 5, a β-1,3-glucanase, and GSL10. We propose that they all might be part of a putative callose synthase complex, allowing a concerted regulation of callose deposition at plasmodesmata. CONCLUSION Analysis of a novel mutant allele of GSL8 reveals that GSL8 is a key player in early seedling development in Arabidopsis. GSL8 is required for maintaining the basic ploidy level and regulating the symplastic trafficking. Callose deposition at plasmodesmata is highly regulated and occurs through interaction of different components, likely to be incorporated into a callose biosynthesis complex. We are providing new evidence supporting an earlier hypothesis that GSL8 might have regulatory roles apart from its enzymatic function in plasmodesmata regulation.
Collapse
Affiliation(s)
- Behnaz Saatian
- Agriculture and Agri-Food Canada, London Research and Development Centre, London, ON Canada
- Department of Biology, Western University, 1391 Sandford St, London, ON N5V 4T3 Canada
| | - Ryan S. Austin
- Agriculture and Agri-Food Canada, London Research and Development Centre, London, ON Canada
- Department of Biology, Western University, 1391 Sandford St, London, ON N5V 4T3 Canada
| | - Gang Tian
- Agriculture and Agri-Food Canada, London Research and Development Centre, London, ON Canada
| | - Chen Chen
- Agriculture and Agri-Food Canada, London Research and Development Centre, London, ON Canada
- Department of Biology, Western University, 1391 Sandford St, London, ON N5V 4T3 Canada
| | - Vi Nguyen
- Agriculture and Agri-Food Canada, London Research and Development Centre, London, ON Canada
| | - Susanne E. Kohalmi
- Department of Biology, Western University, 1391 Sandford St, London, ON N5V 4T3 Canada
| | - Danny Geelen
- In Vitro Biology and Horticulture, Department of Plant Production, University of Ghent, 9000 Ghent, Belgium
| | - Yuhai Cui
- Agriculture and Agri-Food Canada, London Research and Development Centre, London, ON Canada
- Department of Biology, Western University, 1391 Sandford St, London, ON N5V 4T3 Canada
| |
Collapse
|
19
|
Manieu C, Olivares GH, Vega-Macaya F, Valdivia M, Olguín P. Jitterbug/Filamin and Myosin-II form a complex in tendon cells required to maintain epithelial shape and polarity during musculoskeletal system development. Mech Dev 2018; 154:309-314. [PMID: 30213743 DOI: 10.1016/j.mod.2018.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2018] [Revised: 09/07/2018] [Accepted: 09/08/2018] [Indexed: 01/16/2023]
Abstract
During musculoskeletal system development, mechanical tension is generated between muscles and tendon-cells. This tension is required for muscle differentiation and is counterbalanced by tendon-cells avoiding tissue deformation. Both, Jbug/Filamin, an actin-meshwork organizing protein, and non-muscle Myosin-II (Myo-II) are required to maintain the shape and cell orientation of the Drosophila notum epithelium during flight muscle attachment to tendon cells. Here we show that halving the genetic dose of Rho kinase (Drok), the main activator of Myosin-II, enhances the epithelial deformation and bristle orientation defects associated with jbug/Filamin knockdown. Drok and activated Myo-II localize at the apical cell junctions, tendon processes and are associated to the myotendinous junction. Further, we found that Jbug/Filamin co-distribute at tendon cells with activated Myo-II. Finally, we found that Jbug/Filamin and Myo-II are in the same molecular complex and that the actin-binding domain of Jbug/Filamin is necessary for this interaction. These data together suggest that Jbug/Filamin and Myo-II proteins may act together in tendon cells to balance the tension generated during development of muscles-tendon interaction, maintaining the shape and polarity of the Drosophila notum epithelium.
Collapse
Affiliation(s)
- Catalina Manieu
- Program in Human Genetics, Institute of Biomedical Sciences, Biomedical Neurosciences Institute, Department of Neuroscience, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Gonzalo H Olivares
- Program in Human Genetics, Institute of Biomedical Sciences, Biomedical Neurosciences Institute, Department of Neuroscience, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Franco Vega-Macaya
- Program in Human Genetics, Institute of Biomedical Sciences, Biomedical Neurosciences Institute, Department of Neuroscience, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Mauricio Valdivia
- Program in Human Genetics, Institute of Biomedical Sciences, Biomedical Neurosciences Institute, Department of Neuroscience, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Patricio Olguín
- Program in Human Genetics, Institute of Biomedical Sciences, Biomedical Neurosciences Institute, Department of Neuroscience, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
| |
Collapse
|
20
|
Córdoba S, Estella C. The transcription factor Dysfusion promotes fold and joint morphogenesis through regulation of Rho1. PLoS Genet 2018; 14:e1007584. [PMID: 30080872 PMCID: PMC6095628 DOI: 10.1371/journal.pgen.1007584] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 08/16/2018] [Accepted: 07/24/2018] [Indexed: 12/22/2022] Open
Abstract
The mechanisms that control tissue patterning and cell behavior are extensively studied separately, but much less is known about how these two processes are coordinated. Here we show that the Drosophila transcription factor Dysfusion (Dysf) directs leg epithelial folding and joint formation through the regulation of Rho1 activity. We found that Dysf-induced Rho1 activity promotes apical constriction specifically in folding epithelial cells. Here we show that downregulation of Rho1 or its downstream effectors cause defects in fold and joint formation. In addition, Rho1 and its effectors are sufficient to induce the formation of epithelial folds when misexpressed in a flat epithelium. Furthermore, as apoptotic cells can actively control tissue remodeling, we analyzed the role of cell death in the formation of tarsal folds and its relation to Rho1 activity. Surprisingly, we found no defects in this process when apoptosis is inhibited. Our results highlight the coordination between a patterning transcription factor and the cellular processes that cause the cell shape changes necessary to sculpt a flat epithelium into a three dimensional structure. Epithelial morphogenesis drives the formation of organs and the acquisition of body shape. Changes in cell behavior such as cell proliferation, cell shape or apoptosis contribute to the remodeling of the epithelia from a simple layer to a three dimensional structure. These changes have to be precisely regulated by an underlying patterning network to control the final shape of an organ. However, how these two processes are coordinated is mostly unknown. In this work we use the formation of the fly leg joints as a model to study how Dysfusion (Dysf), a patterning transcription factor, regulates the cellular mechanisms that form the folds in the leg discs epithelium. We have found that dysf modulates the localization and activity of Rho1, a key regulator of the acto-myosin cytoskeleton, to drive cell apical constriction and epithelial folding in the leg disc. Furthermore, in this work we provide proof of the direct requirements of Rho1 and its downstream effectors in fold and joint formation. We conclude that Dysf-regulated Rho1 activity controls the cell shape changes that sculpt leg joints.
Collapse
Affiliation(s)
- Sergio Córdoba
- Departamento de Biología Molecular and Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid (UAM)-CSIC, Madrid, Spain
| | - Carlos Estella
- Departamento de Biología Molecular and Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid (UAM)-CSIC, Madrid, Spain
- * E-mail:
| |
Collapse
|
21
|
Sharma A, Halder S, Felix M, Nisaa K, Deshpande G, Prasad M. Insulin signaling modulates border cell movement in Drosophila oogenesis. Development 2018; 145:dev166165. [PMID: 29950391 PMCID: PMC6078333 DOI: 10.1242/dev.166165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 06/18/2018] [Indexed: 12/29/2022]
Abstract
As collective cell migration is intimately involved in different aspects of metazoan development, molecular mechanisms underlying this process are being explored in a variety of developmental contexts. Border cell (BC) migration during Drosophila oogenesis has emerged as an excellent genetic model for studying collective cell migration. BCs are of epithelial origin but acquire partial mesenchymal characteristics before migrating as a group towards the oocyte. Here, we report that insulin signaling modulates collective BC movement during Drosophila oogenesis. Supporting the involvement of Insulin pathway, we demonstrate that compromising Insulin-like Receptor (InR) levels in BCs, inhibits their migration. Furthermore, we show that canonical Insulin signaling pathway components participate in this process. Interestingly, visualization of InR-depleted BC clusters, using time-lapse imaging, revealed a delay in detachment of BC clusters from the surrounding anterior follicle cells and altered protrusion dynamics. Lastly, based on genetic interactions between InR, the polarity determinant, par-1 and a regulatory subunit of Drosophila Myosin (spaghetti squash), we propose that Insulin signaling likely influences par-1 activity to engineer border cell detachment and subsequent movement via Drosophila Myosin.
Collapse
Affiliation(s)
- Aditi Sharma
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur Campus, Mohanpur, 741246 Nadia, West Bengal, India
| | - Sudipta Halder
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur Campus, Mohanpur, 741246 Nadia, West Bengal, India
| | - Martina Felix
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur Campus, Mohanpur, 741246 Nadia, West Bengal, India
| | - Khairun Nisaa
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur Campus, Mohanpur, 741246 Nadia, West Bengal, India
| | - Girish Deshpande
- Department of Molecular Biology, Princeton University, Princeton, NJ 08540, USA
- Indian Institute of Science Education and Research Pune, 411 008 Pune, Maharashtra, India
| | - Mohit Prasad
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur Campus, Mohanpur, 741246 Nadia, West Bengal, India
| |
Collapse
|
22
|
Kiehart DP, Crawford JM, Aristotelous A, Venakides S, Edwards GS. Cell Sheet Morphogenesis: Dorsal Closure in Drosophila melanogaster as a Model System. Annu Rev Cell Dev Biol 2018; 33:169-202. [PMID: 28992442 DOI: 10.1146/annurev-cellbio-111315-125357] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Dorsal closure is a key process during Drosophila morphogenesis that models cell sheet movements in chordates, including neural tube closure, palate formation, and wound healing. Closure occurs midway through embryogenesis and entails circumferential elongation of lateral epidermal cell sheets that close a dorsal hole filled with amnioserosa cells. Signaling pathways regulate the function of cellular structures and processes, including Actomyosin and microtubule cytoskeletons, cell-cell/cell-matrix adhesion complexes, and endocytosis/vesicle trafficking. These orchestrate complex shape changes and movements that entail interactions between five distinct cell types. Genetic and laser perturbation studies establish that closure is robust, resilient, and the consequence of redundancy that contributes to four distinct biophysical processes: contraction of the amnioserosa, contraction of supracellular Actomyosin cables, elongation (stretching?) of the lateral epidermis, and zipping together of two converging cell sheets. What triggers closure and what the emergent properties are that give rise to its extraordinary resilience and fidelity remain key, extant questions.
Collapse
Affiliation(s)
- Daniel P Kiehart
- Department of Biology, Duke University, Durham, North Carolina 27708;
| | - Janice M Crawford
- Department of Biology, Duke University, Durham, North Carolina 27708;
| | - Andreas Aristotelous
- Department of Mathematics, West Chester University, West Chester, Pennsylvania 19383
| | | | - Glenn S Edwards
- Physics Department, Duke University, Durham, North Carolina 27708
| |
Collapse
|
23
|
Koe CT, Tan YS, Lönnfors M, Hur SK, Low CSL, Zhang Y, Kanchanawong P, Bankaitis VA, Wang H. Vibrator and PI4KIIIα govern neuroblast polarity by anchoring non-muscle myosin II. eLife 2018; 7:33555. [PMID: 29482721 PMCID: PMC5828666 DOI: 10.7554/elife.33555] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 01/26/2018] [Indexed: 12/19/2022] Open
Abstract
A central feature of most stem cells is the ability to self-renew and undergo differentiation via asymmetric division. However, during asymmetric division the role of phosphatidylinositol (PI) lipids and their regulators is not well established. Here, we show that the sole type I PI transfer protein, Vibrator, controls asymmetric division of Drosophilaneural stem cells (NSCs) by physically anchoring myosin II regulatory light chain, Sqh, to the NSC cortex. Depletion of vib or disruption of its lipid binding and transfer activities disrupts NSC polarity. We propose that Vib stimulates PI4KIIIα to promote synthesis of a plasma membrane pool of phosphatidylinositol 4-phosphate [PI(4)P] that, in turn, binds and anchors myosin to the NSC cortex. Remarkably, Sqh also binds to PI(4)P in vitro and both Vib and Sqh mediate plasma membrane localization of PI(4)P in NSCs. Thus, reciprocal regulation between Myosin and PI(4)P likely governs asymmetric division of NSCs. Stem cells are cells that can both make copies of themselves and make new cells of various types. They can either divide symmetrically to produce two identical new cells, or they can divide asymmetrically to produce two different cells. Asymmetric division happens because the two new cells contain different molecules. Stem cells drive asymmetric division by moving key molecules to one end of the cell before they divide. Asymmetric division is key to how neural stem cells produce new brain cells. Many studies have used the developing brain of the fruit fly Drosophila melanogaster to understand this process. Errors in asymmetric division can lead to too many stem cells or not enough brain cells. This can contribute to brain tumors and other neurological disorders. Fat molecules called phosphatidylinositol lipids are some of chemicals that cause asymmetry in neural stem cells. Yet, it is not clear how these lipid molecules affect cell behavior to turn stem cells into brain cells. The production of phosphatidylinositol lipids involves proteins called Vibrator and PI4KIIIα. Koe et al. examined the role of these two proteins in asymmetric cell division of neural stem cells in fruit flies. The results show that Vibrator activates PI4KIIIα, which leads to high levels of a phosphatidylinositol lipid called PI(4)P within the cell. These lipids act as an anchor for a group of proteins called myosin, part of the machinery that physically divides the cell. Hence, myosin and phosphatidylinositol lipids together control asymmetric division of neural stem cells. Further experiments used mouse proteins to compensate for defects in the equivalent fly proteins. The results suggest that the same mechanisms are likely to hold true in mammalian brains, although this still needs to be proven. Nevertheless, given that human equivalents of Vibrator and PI4KIIIα are associated with neurodegenerative disorders, schizophrenia or cancers, these new findings are likely to help scientists better to understand several human diseases.
Collapse
Affiliation(s)
- Chwee Tat Koe
- Neuroscience and Behavioral Disorders Programme, Duke-NUS Medical School, Singapore, Singapore
| | - Ye Sing Tan
- Neuroscience and Behavioral Disorders Programme, Duke-NUS Medical School, Singapore, Singapore
| | - Max Lönnfors
- Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, College Station, United States
| | - Seong Kwon Hur
- Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, College Station, United States
| | | | - Yingjie Zhang
- Neuroscience and Behavioral Disorders Programme, Duke-NUS Medical School, Singapore, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Singapore
| | - Pakorn Kanchanawong
- Mechanobiology Institute, National University of Singapore, Singapore, Singapore.,Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Vytas A Bankaitis
- Department of Molecular and Cellular Medicine, Texas A&M University Health Science Center, College Station, United States
| | - Hongyan Wang
- Neuroscience and Behavioral Disorders Programme, Duke-NUS Medical School, Singapore, Singapore.,NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Singapore.,Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| |
Collapse
|
24
|
Tsoumpekos G, Nemetschke L, Knust E. Drosophila Big bang regulates the apical cytocortex and wing growth through junctional tension. J Cell Biol 2018; 217:1033-1045. [PMID: 29326288 PMCID: PMC5839783 DOI: 10.1083/jcb.201705104] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 09/22/2017] [Accepted: 11/28/2017] [Indexed: 01/28/2023] Open
Abstract
Growth of epithelial tissues is regulated by a plethora of components, including signaling and scaffolding proteins, but also by junctional tension, mediated by the actomyosin cytoskeleton. However, how these players are spatially organized and functionally coordinated is not well understood. Here, we identify the Drosophila melanogaster scaffolding protein Big bang as a novel regulator of growth in epithelial cells of the wing disc by ensuring proper junctional tension. Loss of big bang results in the reduction of the regulatory light chain of nonmuscle myosin, Spaghetti squash. This is associated with an increased apical cell surface, decreased junctional tension, and smaller wings. Strikingly, these phenotypic traits of big bang mutant discs can be rescued by expressing constitutively active Spaghetti squash. Big bang colocalizes with Spaghetti squash in the apical cytocortex and is found in the same protein complex. These results suggest that in epithelial cells of developing wings, the scaffolding protein Big bang controls apical cytocortex organization, which is important for regulating cell shape and tissue growth.
Collapse
Affiliation(s)
- Giorgos Tsoumpekos
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Linda Nemetschke
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Elisabeth Knust
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| |
Collapse
|
25
|
Palani S, Srinivasan R, Zambon P, Kamnev A, Gayathri P, Balasubramanian MK. Steric hindrance in the upper 50 kDa domain of the motor Myo2p leads to cytokinesis defects in fission yeast. J Cell Sci 2018; 131:jcs.205625. [PMID: 29162650 PMCID: PMC5818058 DOI: 10.1242/jcs.205625] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 11/06/2017] [Indexed: 02/05/2023] Open
Abstract
Cytokinesis in many eukaryotes requires a contractile actomyosin ring that is placed at the division site. In fission yeast, which is an attractive organism for the study of cytokinesis, actomyosin ring assembly and contraction requires the myosin II heavy chain Myo2p. Although myo2-E1, a temperature-sensitive mutant defective in the upper 50 kDa domain of Myo2p, has been studied extensively, the molecular basis of the cytokinesis defect is not understood. Here, we isolate myo2-E1-Sup2, an intragenic suppressor that contains the original mutation in myo2-E1 (G345R) and a second mutation in the upper 50 kDa domain (Y297C). Unlike myo2-E1-Sup1, a previously characterized myo2-E1 suppressor, myo2-E1-Sup2 reverses actomyosin ring contraction defects in vitro and in vivo Structural analysis of available myosin motor domain conformations suggests that a steric clash in myo2-E1, which is caused by the replacement of a glycine with a bulky arginine, is relieved in myo2-E1-Sup2 by mutation of a tyrosine to a smaller cysteine. Our work provides insight into the function of the upper 50 kDa domain of Myo2p, informs a molecular basis for the cytokinesis defect in myo2-E1, and may be relevant to the understanding of certain cardiomyopathies.
Collapse
Affiliation(s)
- Saravanan Palani
- Centre for Mechanochemical Cell Biology and Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
| | - Ramanujam Srinivasan
- School of Biological Sciences, National Institute of Science Engineering and Research (NISER), Bhubaneswar, Odisha 752050, India
| | - Paola Zambon
- Centre for Mechanochemical Cell Biology and Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
| | - Anton Kamnev
- Centre for Mechanochemical Cell Biology and Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
| | - Pananghat Gayathri
- Biology Division, Indian Institute of Science Education and Research (IISER), Pune 411 008, India
| | - Mohan K Balasubramanian
- Centre for Mechanochemical Cell Biology and Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
| |
Collapse
|
26
|
Rothenbusch-Fender S, Fritzen K, Bischoff MC, Buttgereit D, Oenel SF, Renkawitz-Pohl R. Myotube migration to cover and shape the testis of Drosophila depends on Heartless, Cadherin/Catenin, and myosin II. Biol Open 2017; 6:1876-1888. [PMID: 29122742 PMCID: PMC5769643 DOI: 10.1242/bio.025940] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
During Drosophila metamorphosis, nascent testis myotubes migrate from the prospective seminal vesicle of the genital disc onto pupal testes and then further to cover the testes with multinucleated smooth-like muscles. Here we show that DWnt2 is likely required for determination of testis-relevant myoblasts on the genital disc. Knock down of fibroblast growth factor receptor (FGFR) heartless by RNAi and a dominant-negative version revealed multiple functions of Heartless, namely regulation of the amount of myoblasts on the genital disc, connection of seminal vesicles and testes, and migration of muscles along the testes. Live imaging indicated that the downstream effector Stumps is required for migration of testis myotubes on the testis towards the apical tip. After myoblast fusion, myosin II is needed for migration of nascent testis myotubes, in which Thisbe-dependent fibroblast growth factor (FGF) signaling is activated. Cadherin-N is essential for connecting these single myofibers and for creating a firm testis muscle sheath that shapes and stabilizes the testis tubule. Based on these results, we propose a model for the migration of testis myotubes in which nascent testis myotubes migrate as a collective onto and along the testis, dependent on FGF-regulated expression of myosin II. Summary:Drosophila testes and mammalian seminiferous tubules are surrounded by a muscle layer. Drosophila myotubes migrate towards testes in dependence of the FGF receptor Heartless, myosin II and Cadherin-N.
Collapse
Affiliation(s)
- Silke Rothenbusch-Fender
- Philipps-Universität Marburg, Fachbereich Biologie, Entwicklungsbiologie, Karl-von-Frisch Straße 8, 35043 Marburg, Germany.,DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-Universität Marburg, 35043 Marburg, Germany
| | - Katharina Fritzen
- Philipps-Universität Marburg, Fachbereich Biologie, Entwicklungsbiologie, Karl-von-Frisch Straße 8, 35043 Marburg, Germany
| | - Maik C Bischoff
- Philipps-Universität Marburg, Fachbereich Biologie, Entwicklungsbiologie, Karl-von-Frisch Straße 8, 35043 Marburg, Germany.,DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-Universität Marburg, 35043 Marburg, Germany
| | - Detlev Buttgereit
- Philipps-Universität Marburg, Fachbereich Biologie, Entwicklungsbiologie, Karl-von-Frisch Straße 8, 35043 Marburg, Germany
| | - Susanne F Oenel
- Philipps-Universität Marburg, Fachbereich Biologie, Entwicklungsbiologie, Karl-von-Frisch Straße 8, 35043 Marburg, Germany.,DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-Universität Marburg, 35043 Marburg, Germany
| | - Renate Renkawitz-Pohl
- Philipps-Universität Marburg, Fachbereich Biologie, Entwicklungsbiologie, Karl-von-Frisch Straße 8, 35043 Marburg, Germany .,DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-Universität Marburg, 35043 Marburg, Germany
| |
Collapse
|
27
|
Bianchi FT, Tocco C, Pallavicini G, Liu Y, Vernì F, Merigliano C, Bonaccorsi S, El-Assawy N, Priano L, Gai M, Berto GE, Chiotto AMA, Sgrò F, Caramello A, Tasca L, Ala U, Neri F, Oliviero S, Mauro A, Geley S, Gatti M, Di Cunto F. Citron Kinase Deficiency Leads to Chromosomal Instability and TP53-Sensitive Microcephaly. Cell Rep 2017; 18:1674-1686. [PMID: 28199840 PMCID: PMC5318669 DOI: 10.1016/j.celrep.2017.01.054] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 12/16/2016] [Accepted: 01/22/2017] [Indexed: 11/16/2022] Open
Abstract
Mutations in citron (CIT), leading to loss or inactivation of the citron kinase protein (CITK), cause primary microcephaly in humans and rodents, associated with cytokinesis failure and apoptosis in neural progenitors. We show that CITK loss induces DNA damage accumulation and chromosomal instability in both mammals and Drosophila. CITK-deficient cells display "spontaneous" DNA damage, increased sensitivity to ionizing radiation, and defective recovery from radiation-induced DNA lesions. In CITK-deficient cells, DNA double-strand breaks increase independently of cytokinesis failure. Recruitment of RAD51 to DNA damage foci is compromised by CITK loss, and CITK physically interacts with RAD51, suggesting an involvement of CITK in homologous recombination. Consistent with this scenario, in doubly CitK and Trp53 mutant mice, neural progenitor cell death is dramatically reduced; moreover, clinical and neuroanatomical phenotypes are remarkably improved. Our results underscore a crucial role of CIT in the maintenance of genomic integrity during brain development.
Collapse
Affiliation(s)
- Federico Tommaso Bianchi
- Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy; Neuroscience Institute Cavalieri Ottolenghi, University of Turin, 10043 Orbassano (TO), Italy.
| | - Chiara Tocco
- Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy
| | - Gianmarco Pallavicini
- Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy; Neuroscience Institute Cavalieri Ottolenghi, University of Turin, 10043 Orbassano (TO), Italy
| | - Yifan Liu
- Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy
| | - Fiammetta Vernì
- Department of Biology and Biotechnology "Charles Darwin," Sapienza University, 00185 Rome, Italy
| | - Chiara Merigliano
- Department of Biology and Biotechnology "Charles Darwin," Sapienza University, 00185 Rome, Italy
| | - Silvia Bonaccorsi
- Department of Biology and Biotechnology "Charles Darwin," Sapienza University, 00185 Rome, Italy
| | - Nadia El-Assawy
- Department of Neurology and Neurorehabilitation, San Giuseppe Hospital, Istituto Auxologico Italiano IRCCS, 28824 Piancavallo (VB), Italy
| | - Lorenzo Priano
- Department of Neurology and Neurorehabilitation, San Giuseppe Hospital, Istituto Auxologico Italiano IRCCS, 28824 Piancavallo (VB), Italy; Department of Neuroscience, University of Torino, 10126 Torino, Italy
| | - Marta Gai
- Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy
| | - Gaia Elena Berto
- Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy; Neuroscience Institute Cavalieri Ottolenghi, University of Turin, 10043 Orbassano (TO), Italy
| | - Alessandra Maria Adelaide Chiotto
- Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy; Neuroscience Institute Cavalieri Ottolenghi, University of Turin, 10043 Orbassano (TO), Italy
| | - Francesco Sgrò
- Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy
| | - Alessia Caramello
- Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy
| | - Laura Tasca
- Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy; Neuroscience Institute Cavalieri Ottolenghi, University of Turin, 10043 Orbassano (TO), Italy
| | - Ugo Ala
- Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy
| | - Francesco Neri
- Human Genetics Foundation (HuGeF), via Nizza 52, 10126 Torino, Italy
| | | | - Alessandro Mauro
- Department of Neurology and Neurorehabilitation, San Giuseppe Hospital, Istituto Auxologico Italiano IRCCS, 28824 Piancavallo (VB), Italy; Department of Neuroscience, University of Torino, 10126 Torino, Italy
| | - Stephan Geley
- Division of Molecular Pathophysiology, Biocenter, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Maurizio Gatti
- Department of Biology and Biotechnology "Charles Darwin," Sapienza University, 00185 Rome, Italy; Institute of Molecular Biology and Pathology (IBPM), CNR, 00185 Rome, Italy
| | - Ferdinando Di Cunto
- Department of Molecular Biotechnology and Health Sciences, University of Turin, 10126 Turin, Italy; Neuroscience Institute Cavalieri Ottolenghi, University of Turin, 10043 Orbassano (TO), Italy.
| |
Collapse
|
28
|
Roubinet C, Tsankova A, Pham TT, Monnard A, Caussinus E, Affolter M, Cabernard C. Spatio-temporally separated cortical flows and spindle geometry establish physical asymmetry in fly neural stem cells. Nat Commun 2017; 8:1383. [PMID: 29123099 PMCID: PMC5680339 DOI: 10.1038/s41467-017-01391-w] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 09/04/2017] [Indexed: 01/09/2023] Open
Abstract
Asymmetric cell division, creating sibling cells with distinct developmental potentials, can be manifested in sibling cell size asymmetry. This form of physical asymmetry occurs in several metazoan cells, but the underlying mechanisms and function are incompletely understood. Here we use Drosophila neural stem cells to elucidate the mechanisms involved in physical asymmetry establishment. We show that Myosin relocalizes to the cleavage furrow via two distinct cortical Myosin flows: at anaphase onset, a polarity induced, basally directed Myosin flow clears Myosin from the apical cortex. Subsequently, mitotic spindle cues establish a Myosin gradient at the lateral neuroblast cortex, necessary to trigger an apically directed flow, removing Actomyosin from the basal cortex. On the basis of the data presented here, we propose that spatiotemporally controlled Myosin flows in conjunction with spindle positioning and spindle asymmetry are key determinants for correct cleavage furrow placement and cortical expansion, thereby establishing physical asymmetry.
Collapse
Affiliation(s)
- Chantal Roubinet
- Biozentrum, University of Basel, Klingelbergstrasse 50-70, CH-4056, Basel, Switzerland
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Anna Tsankova
- Biozentrum, University of Basel, Klingelbergstrasse 50-70, CH-4056, Basel, Switzerland
- Streuli Pharma AG, Bahnhofstrasse 7, CH-8730, Uznach, Switzerland
| | - Tri Thanh Pham
- Biozentrum, University of Basel, Klingelbergstrasse 50-70, CH-4056, Basel, Switzerland
- Department of Biology, University of Washington, 24 Kincaid Hall, Seattle, WA, 98195, USA
| | - Arnaud Monnard
- Biozentrum, University of Basel, Klingelbergstrasse 50-70, CH-4056, Basel, Switzerland
- Department of Biology, University of Washington, 24 Kincaid Hall, Seattle, WA, 98195, USA
| | - Emmanuel Caussinus
- Biozentrum, University of Basel, Klingelbergstrasse 50-70, CH-4056, Basel, Switzerland
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland
| | - Markus Affolter
- Biozentrum, University of Basel, Klingelbergstrasse 50-70, CH-4056, Basel, Switzerland
| | - Clemens Cabernard
- Biozentrum, University of Basel, Klingelbergstrasse 50-70, CH-4056, Basel, Switzerland.
- Department of Biology, University of Washington, 24 Kincaid Hall, Seattle, WA, 98195, USA.
| |
Collapse
|
29
|
Ochoa-Espinosa A, Harmansa S, Caussinus E, Affolter M. Myosin II is not required for Drosophila tracheal branch elongation and cell intercalation. Development 2017; 144:2961-2968. [PMID: 28811312 DOI: 10.1242/dev.148940] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 07/05/2017] [Indexed: 01/04/2023]
Abstract
The Drosophila tracheal system consists of an interconnected network of monolayered epithelial tubes that ensures oxygen transport in the larval and adult body. During tracheal dorsal branch (DB) development, individual DBs elongate as a cluster of cells, led by tip cells at the front and trailing cells in the rear. Branch elongation is accompanied by extensive cell intercalation and cell lengthening of the trailing stalk cells. Although cell intercalation is governed by Myosin II (MyoII)-dependent forces during tissue elongation in the Drosophila embryo that lead to germ-band extension, it remained unclear whether MyoII plays a similar active role during tracheal branch elongation and intercalation. Here, we have used a nanobody-based approach to selectively knock down MyoII in tracheal cells. Our data show that, despite the depletion of MyoII function, tip cell migration and stalk cell intercalation (SCI) proceed at a normal rate. This confirms a model in which DB elongation and SCI in the trachea occur as a consequence of tip cell migration, which produces the necessary forces for the branching process.
Collapse
Affiliation(s)
| | - Stefan Harmansa
- Biozentrum, University of Basel, Klingelbergstr. 50/70, 4056 Basel, Switzerland
| | - Emmanuel Caussinus
- Institute of Molecular Life Sciences (IMLS), University of Zurich, 8057 Zurich, Switzerland
| | - Markus Affolter
- Biozentrum, University of Basel, Klingelbergstr. 50/70, 4056 Basel, Switzerland
| |
Collapse
|
30
|
Montembault E, Claverie MC, Bouit L, Landmann C, Jenkins J, Tsankova A, Cabernard C, Royou A. Myosin efflux promotes cell elongation to coordinate chromosome segregation with cell cleavage. Nat Commun 2017; 8:326. [PMID: 28835609 PMCID: PMC5569077 DOI: 10.1038/s41467-017-00337-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 06/21/2017] [Indexed: 12/02/2022] Open
Abstract
Chromatid segregation must be coordinated with cytokinesis to preserve genomic stability. Here we report that cells clear trailing chromatids from the cleavage site by undergoing two phases of cell elongation. The first phase relies on the assembly of a wide contractile ring. The second phase requires the activity of a pool of myosin that flows from the ring and enriches the nascent daughter cell cortices. This myosin efflux is a novel feature of cytokinesis and its duration is coupled to nuclear envelope reassembly and the nuclear sequestration of the Rho-GEF Pebble. Trailing chromatids induce a delay in nuclear envelope reassembly concomitant with prolonged cortical myosin activity, thus providing forces for the second elongation. We propose that the modulation of cortical myosin dynamics is part of the cellular response triggered by a “chromatid separation checkpoint” that delays nuclear envelope reassembly and, consequently, Pebble nuclear sequestration when trailing chromatids are present at the midzone. Chromatid segregation must be coordinated with cytokinesis to preserve genomic stability. Here the authors show that cells clear trailing chromatids from the cleavage site in a two-step cell elongation and demonstrate the role of myosin efflux in the second phase.
Collapse
Affiliation(s)
- Emilie Montembault
- University of Bordeaux, CNRS, UMR5095, Institut Européen de Chimie et Biologie, 2 Rue Robert Escarpit, Pessac, 33607, France.
| | - Marie-Charlotte Claverie
- University of Bordeaux, CNRS, UMR5095, Institut Européen de Chimie et Biologie, 2 Rue Robert Escarpit, Pessac, 33607, France
| | - Lou Bouit
- University of Bordeaux, CNRS, UMR5095, Institut Européen de Chimie et Biologie, 2 Rue Robert Escarpit, Pessac, 33607, France
| | - Cedric Landmann
- University of Bordeaux, CNRS, UMR5095, Institut Européen de Chimie et Biologie, 2 Rue Robert Escarpit, Pessac, 33607, France
| | - James Jenkins
- University of Bordeaux, CNRS, UMR5095, Institut Européen de Chimie et Biologie, 2 Rue Robert Escarpit, Pessac, 33607, France
| | - Anna Tsankova
- Department of Biology, University of Washington, Seattle, WA, 98195, USA
| | - Clemens Cabernard
- Department of Biology, University of Washington, Seattle, WA, 98195, USA
| | - Anne Royou
- University of Bordeaux, CNRS, UMR5095, Institut Européen de Chimie et Biologie, 2 Rue Robert Escarpit, Pessac, 33607, France.
| |
Collapse
|
31
|
Chan EH, Chavadimane Shivakumar P, Clément R, Laugier E, Lenne PF. Patterned cortical tension mediated by N-cadherin controls cell geometric order in the Drosophila eye. eLife 2017; 6. [PMID: 28537220 PMCID: PMC5443664 DOI: 10.7554/elife.22796] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Accepted: 05/08/2017] [Indexed: 12/22/2022] Open
Abstract
Adhesion molecules hold cells together but also couple cell membranes to a contractile actomyosin network, which limits the expansion of cell contacts. Despite their fundamental role in tissue morphogenesis and tissue homeostasis, how adhesion molecules control cell shapes and cell patterns in tissues remains unclear. Here we address this question in vivo using the Drosophila eye. We show that cone cell shapes depend little on adhesion bonds and mostly on contractile forces. However, N-cadherin has an indirect control on cell shape. At homotypic contacts, junctional N-cadherin bonds downregulate Myosin-II contractility. At heterotypic contacts with E-cadherin, unbound N-cadherin induces an asymmetric accumulation of Myosin-II, which leads to a highly contractile cell interface. Such differential regulation of contractility is essential for morphogenesis as loss of N-cadherin disrupts cell rearrangements. Our results establish a quantitative link between adhesion and contractility and reveal an unprecedented role of N-cadherin on cell shapes and cell arrangements. DOI:http://dx.doi.org/10.7554/eLife.22796.001
Collapse
|
32
|
Simões S, Oh Y, Wang MFZ, Fernandez-Gonzalez R, Tepass U. Myosin II promotes the anisotropic loss of the apical domain during Drosophila neuroblast ingression. J Cell Biol 2017; 216:1387-1404. [PMID: 28363972 PMCID: PMC5412560 DOI: 10.1083/jcb.201608038] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 12/15/2016] [Accepted: 02/14/2017] [Indexed: 01/06/2023] Open
Abstract
Drosophila neural stem cells, or neuroblasts, ingress from the neuroepithelium in an EMT-like process, during which the apical cell domain is lost. Apical constriction of neuroblasts and the serial loss of cell–cell contacts require periodic pulses of actomyosin that cause progressively stronger ratcheted contractions of the neuroblast apical cortex. Epithelial–mesenchymal transitions play key roles in development and cancer and entail the loss of epithelial polarity and cell adhesion. In this study, we use quantitative live imaging of ingressing neuroblasts (NBs) in Drosophila melanogaster embryos to assess apical domain loss and junctional disassembly. Ingression is independent of the Snail family of transcriptional repressors and down-regulation of Drosophila E-cadherin (DEcad) transcription. Instead, the posttranscriptionally regulated decrease in DEcad coincides with the reduction of cell contact length and depends on tension anisotropy between NBs and their neighbors. A major driver of apical constriction and junctional disassembly are periodic pulses of junctional and medial myosin II that result in progressively stronger cortical contractions during ingression. Effective contractions require the molecular coupling between myosin and junctions and apical relaxation of neighboring cells. Moreover, planar polarization of myosin leads to the loss of anterior–posterior junctions before the loss of dorsal–ventral junctions. We conclude that planar-polarized dynamic actomyosin networks drive apical constriction and the anisotropic loss of cell contacts during NB ingression.
Collapse
Affiliation(s)
- Sérgio Simões
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Youjin Oh
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| | - Michael F Z Wang
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 1M1, Canada
| | - Rodrigo Fernandez-Gonzalez
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 1M1, Canada
| | - Ulrich Tepass
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario M5S 3G5, Canada
| |
Collapse
|
33
|
Basolateral protrusion and apical contraction cooperatively drive Drosophila germ-band extension. Nat Cell Biol 2017; 19:375-383. [DOI: 10.1038/ncb3497] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 02/23/2017] [Indexed: 12/16/2022]
|
34
|
The PCP pathway regulates Baz planar distribution in epithelial cells. Sci Rep 2016; 6:33420. [PMID: 27624969 PMCID: PMC5022056 DOI: 10.1038/srep33420] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 08/26/2016] [Indexed: 01/05/2023] Open
Abstract
The localisation of apico-basal polarity proteins along the Z-axis of epithelial cells is well understood while their distribution in the plane of the epithelium is poorly characterised. Here we provide a systematic description of the planar localisation of apico-basal polarity proteins in the Drosophila ommatidial epithelium. We show that the adherens junction proteins Shotgun and Armadillo, as well as the baso-lateral complexes, are bilateral, i.e. present on both sides of cell interfaces. In contrast, we report that other key adherens junction proteins, Bazooka and the myosin regulatory light chain (Spaghetti squash) are unilateral, i.e. present on one side of cell interfaces. Furthermore, we demonstrate that planar cell polarity (PCP) and not the apical determinants Crumbs and Par-6 control Bazooka unilaterality in cone cells. Altogether, our work unravels an unexpected organisation and combination of apico-basal, cytoskeletal and planar polarity proteins that is different on either side of cell-cell interfaces and unique for the different contacts of the same cell.
Collapse
|
35
|
He B, Martin A, Wieschaus E. Flow-dependent myosin recruitment during Drosophila cellularization requires zygotic dunk activity. Development 2016; 143:2417-30. [PMID: 27226317 PMCID: PMC4958320 DOI: 10.1242/dev.131334] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 05/18/2016] [Indexed: 12/12/2022]
Abstract
Actomyosin contractility underlies force generation in morphogenesis ranging from cytokinesis to epithelial extension or invagination. In Drosophila, the cleavage of the syncytial blastoderm is initiated by an actomyosin network at the base of membrane furrows that invaginate from the surface of the embryo. It remains unclear how this network forms and how it affects tissue mechanics. Here, we show that during Drosophila cleavage, myosin recruitment to the cleavage furrows proceeds in temporally distinct phases of tension-driven cortical flow and direct recruitment, regulated by different zygotic genes. We identify the gene dunk, which we show is transiently transcribed when cellularization starts and functions to maintain cortical myosin during the flow phase. The subsequent direct myosin recruitment, however, is Dunk-independent but requires Slam. The Slam-dependent direct recruitment of myosin is sufficient to drive cleavage in the dunk mutant, and the subsequent development of the mutant is normal. In the dunk mutant, cortical myosin loss triggers misdirected flow and disrupts the hexagonal packing of the ingressing furrows. Computer simulation coupled with laser ablation suggests that Dunk-dependent maintenance of cortical myosin enables mechanical tension build-up, thereby providing a mechanism to guide myosin flow and define the hexagonal symmetry of the furrows. Summary: During Drosophila cellularisation, myosin recruitment to the cleavage furrows proceeds in temporally and mechanistically distinct phases separately regulated by dunk and slam.
Collapse
Affiliation(s)
- Bing He
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Adam Martin
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA HHMI, Princeton University, Princeton, NJ 08544, USA
| | - Eric Wieschaus
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA HHMI, Princeton University, Princeton, NJ 08544, USA
| |
Collapse
|
36
|
Jodoin JN, Coravos JS, Chanet S, Vasquez CG, Tworoger M, Kingston ER, Perkins LA, Perrimon N, Martin AC. Stable Force Balance between Epithelial Cells Arises from F-Actin Turnover. Dev Cell 2015; 35:685-97. [PMID: 26688336 DOI: 10.1016/j.devcel.2015.11.018] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 10/08/2015] [Accepted: 11/17/2015] [Indexed: 01/06/2023]
Abstract
The propagation of force in epithelial tissues requires that the contractile cytoskeletal machinery be stably connected between cells through E-cadherin-containing adherens junctions. In many epithelial tissues, the cells' contractile network is positioned at a distance from the junction. However, the mechanism or mechanisms that connect the contractile networks to the adherens junctions, and thus mechanically connect neighboring cells, are poorly understood. Here, we identified the role for F-actin turnover in regulating the contractile cytoskeletal network's attachment to adherens junctions. Perturbing F-actin turnover via gene depletion or acute drug treatments that slow F-actin turnover destabilized the attachment between the contractile actomyosin network and adherens junctions. Our work identifies a critical role for F-actin turnover in connecting actomyosin to intercellular junctions, defining a dynamic process required for the stability of force balance across intercellular contacts in tissues.
Collapse
Affiliation(s)
- Jeanne N Jodoin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Jonathan S Coravos
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Soline Chanet
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Claudia G Vasquez
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Michael Tworoger
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Elena R Kingston
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | | | - Norbert Perrimon
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Boston, MA 02115, USA
| | - Adam C Martin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
| |
Collapse
|
37
|
DeBruhl H, Albertson R, Swider Z, Sullivan W. Rop, the Sec1/Munc18 homolog in Drosophila, is required for furrow ingression and stable cell shape during cytokinesis. J Cell Sci 2015; 129:430-43. [PMID: 26631487 DOI: 10.1242/jcs.179200] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 11/30/2015] [Indexed: 01/08/2023] Open
Abstract
Physically separating daughter cells during cytokinesis requires contraction of an actin-myosin ring and vesicle-mediated membrane addition at the cleavage furrow. To identify vesicle trafficking proteins that function in cytokinesis, we screened deficiencies and mutations of candidate genes by live imaging the mitotic domains of the Drosophila embryo. In embryos homozygous for some of these deficiencies, we observed several cytokinesis phenotypes, including slow furrow ingression and increased membrane blebbing. We also found that cytokinesis required the Sec1/Munc18 homolog Rop, which interacts with syntaxin and mediates exocytosis at the plasma membrane. In a temperature-sensitive Rop mutant (Rop(TS)), the contractile ring disassembled during furrow ingression, indicating that maintenance of the ring required vesicle addition. Furthermore, in some dividing Rop(TS) cells, the shape of the daughter cells became unstable, causing cytokinesis failure. These results further highlight the importance of vesicle trafficking in animal cytokinesis and show that vesicle fusion influences cell shape during cytokinesis.
Collapse
Affiliation(s)
- Heather DeBruhl
- Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, CA 95064, USA
| | | | - Zachary Swider
- Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, CA 95064, USA
| | - William Sullivan
- Molecular, Cell and Developmental Biology, University of California at Santa Cruz, Santa Cruz, CA 95064, USA
| |
Collapse
|
38
|
Liu C, Xiong Y, Feng J, Zhang L, Zhao Y. Sqh is involved in the regulation of Ci stability in Hh signaling pathway. J Mol Cell Biol 2015; 7:584-7. [PMID: 26518439 DOI: 10.1093/jmcb/mjv063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Chunying Liu
- State Key Laboratory of Cell Biology, Innovation Center for Cell Signaling Network, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yue Xiong
- State Key Laboratory of Cell Biology, Innovation Center for Cell Signaling Network, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jing Feng
- State Key Laboratory of Cell Biology, Innovation Center for Cell Signaling Network, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Lei Zhang
- State Key Laboratory of Cell Biology, Innovation Center for Cell Signaling Network, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China School of Life Science and Technology, ShanghaiTech University, Shanghai 200031, China
| | - Yun Zhao
- State Key Laboratory of Cell Biology, Innovation Center for Cell Signaling Network, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China School of Life Science and Technology, ShanghaiTech University, Shanghai 200031, China
| |
Collapse
|
39
|
The elimination of an adult segment by the Hox gene Abdominal-B. Mech Dev 2015; 138 Pt 2:210-217. [DOI: 10.1016/j.mod.2015.08.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Revised: 07/31/2015] [Accepted: 08/01/2015] [Indexed: 11/19/2022]
|
40
|
Abstract
Tissue morphogenesis is orchestrated by cell shape changes. Forces required to power these changes are generated by non-muscle myosin II (MyoII) motor proteins pulling filamentous actin (F-actin). Actomyosin networks undergo cycles of assembly and disassembly (pulses) to cause cell deformations alternating with steps of stabilization to result in irreversible shape changes. Although this ratchet-like behaviour operates in a variety of contexts, the underlying mechanisms remain unclear. Here we investigate the role of MyoII regulation through the conserved Rho1-Rok pathway during Drosophila melanogaster germband extension. This morphogenetic process is powered by cell intercalation, which involves the shrinkage of junctions in the dorsal-ventral axis (vertical junctions) followed by junction extension in the anterior-posterior axis. While polarized flows of medial-apical MyoII pulses deform vertical junctions, MyoII enrichment on these junctions (planar polarity) stabilizes them. We identify two critical properties of MyoII dynamics that underlie stability and pulsatility: exchange kinetics governed by phosphorylation-dephosphorylation cycles of the MyoII regulatory light chain; and advection due to contraction of the motors on F-actin networks. Spatial control over MyoII exchange kinetics establishes two stable regimes of high and low dissociation rates, resulting in MyoII planar polarity. Pulsatility emerges at intermediate dissociation rates, enabling convergent advection of MyoII and its upstream regulators Rho1 GTP, Rok and MyoII phosphatase. Notably, pulsatility is not an outcome of an upstream Rho1 pacemaker. Rather, it is a self-organized system that involves positive and negative biomechanical feedback between MyoII advection and dissociation rates.
Collapse
|
41
|
Taniguchi K, Kokuryo A, Imano T, Minami R, Nakagoshi H, Adachi-Yamada T. Isoform-specific functions of Mud/NuMA mediate binucleation of Drosophila male accessory gland cells. BMC DEVELOPMENTAL BIOLOGY 2014; 14:46. [PMID: 25527079 PMCID: PMC4300151 DOI: 10.1186/s12861-014-0046-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 12/11/2014] [Indexed: 02/01/2023]
Abstract
Background In standard cell division, the cells undergo karyokinesis and then cytokinesis. Some cells, however, such as cardiomyocytes and hepatocytes, can produce binucleate cells by going through mitosis without cytokinesis. This cytokinesis skipping is thought to be due to the inhibition of cytokinesis machinery such as the central spindle or the contractile ring, but the mechanisms regulating it are unclear. We investigated them by characterizing the binucleation event during development of the Drosophila male accessory gland, in which all cells are binucleate. Results The accessory gland cells arrested the cell cycle at 50 hours after puparium formation (APF) and in the middle of the pupal stage stopped proliferating for 5 hours. They then restarted the cell cycle and at 55 hours APF entered the M-phase synchronously. At this stage, accessory gland cells binucleated by mitosis without cytokinesis. Binucleating cells displayed the standard karyokinesis progression but also showed unusual features such as a non-round shape, spindle orientation along the apico-basal axis, and poor assembly of the central spindle. Mud, a Drosophila homolog of NuMA, regulated the processes responsible for these three features, the classical isoform MudPBD and the two newly characterized isoforms MudL and MudS regulated them differently: MudL repressed cell rounding, MudPBD and MudS oriented the spindle along the apico-basal axis, and MudS and MudL repressed central spindle assembly. Importantly, overexpression of MudS induced binucleation even in standard proliferating cells such as those in imaginal discs. Conclusions We characterized the binucleation in the Drosophila male accessory gland and examined mechanisms that regulated unusual morphologies of binucleating cells. We demonstrated that Mud, a microtubule binding protein regulating spindle orientation, was involved in this binucleation. We suggest that atypical functions exerted by three structurally different isoforms of Mud regulate cell rounding, spindle orientation and central spindle assembly in binucleation. We also propose that MudS is a key regulator triggering cytokinesis skipping in binucleation processes. Electronic supplementary material The online version of this article (doi:10.1186/s12861-014-0046-5) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Kiichiro Taniguchi
- Department of Life Science, Faculty of Science, Gakushuin University, Tokyo, 171-8588, Japan.
| | - Akihiko Kokuryo
- Institute for Biomolecular Science, Gakushuin University, Tokyo, 171-8588, Japan. .,Department of Biology, Graduate School of Science, Kobe University, Kobe, 657-8501, Japan.
| | - Takao Imano
- Institute for Biomolecular Science, Gakushuin University, Tokyo, 171-8588, Japan. .,Department of Biology, Graduate School of Science, Kobe University, Kobe, 657-8501, Japan.
| | - Ryunosuke Minami
- Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan.
| | - Hideki Nakagoshi
- Graduate School of Natural Science and Technology, Okayama University, Okayama, 700-8530, Japan.
| | - Takashi Adachi-Yamada
- Department of Life Science, Faculty of Science, Gakushuin University, Tokyo, 171-8588, Japan. .,Institute for Biomolecular Science, Gakushuin University, Tokyo, 171-8588, Japan. .,Department of Biology, Graduate School of Science, Kobe University, Kobe, 657-8501, Japan.
| |
Collapse
|
42
|
Mulinari S, Häcker U. Rho-guanine nucleotide exchange factors during development: Force is nothing without control. Small GTPases 2014; 1:28-43. [PMID: 21686118 DOI: 10.4161/sgtp.1.1.12672] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2010] [Revised: 05/31/2010] [Accepted: 06/14/2010] [Indexed: 01/04/2023] Open
Abstract
The development of multicellular organisms is associated with extensive rearrangements of tissues and cell sheets. The driving force for these rearrangements is generated mostly by the actin cytoskeleton. In order to permit the reproducible development of a specific body plan, dynamic reorganization of the actin cytoskeleton must be precisely coordinated in space and time. GTP-exchange factors that activate small GTPases of the Rho family play an important role in this process. Here we review the role of this class of cytoskeletal regulators during important developmental processes such as epithelial morphogenesis, cytokinesis, cell migration, cell polarity, neuronal growth cone extension and phagocytosis in different model systems.
Collapse
Affiliation(s)
- Shai Mulinari
- Department of Experimental Medical Science; Lund Strategic Research Center for Stem Cell Biology and Cell Therapy; Lund University; Lund, Sweden
| | | |
Collapse
|
43
|
Vasquez CG, Tworoger M, Martin AC. Dynamic myosin phosphorylation regulates contractile pulses and tissue integrity during epithelial morphogenesis. ACTA ACUST UNITED AC 2014; 206:435-50. [PMID: 25092658 PMCID: PMC4121972 DOI: 10.1083/jcb.201402004] [Citation(s) in RCA: 114] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Apical constriction is a cell shape change that promotes epithelial bending. Activation of nonmuscle myosin II (Myo-II) by kinases such as Rho-associated kinase (Rok) is important to generate contractile force during apical constriction. Cycles of Myo-II assembly and disassembly, or pulses, are associated with apical constriction during Drosophila melanogaster gastrulation. It is not understood whether Myo-II phosphoregulation organizes contractile pulses or whether pulses are important for tissue morphogenesis. Here, we show that Myo-II pulses are associated with pulses of apical Rok. Mutants that mimic Myo-II light chain phosphorylation or depletion of myosin phosphatase inhibit Myo-II contractile pulses, disrupting both actomyosin coalescence into apical foci and cycles of Myo-II assembly/disassembly. Thus, coupling dynamic Myo-II phosphorylation to upstream signals organizes contractile Myo-II pulses in both space and time. Mutants that mimic Myo-II phosphorylation undergo continuous, rather than incremental, apical constriction. These mutants fail to maintain intercellular actomyosin network connections during tissue invagination, suggesting that Myo-II pulses are required for tissue integrity during morphogenesis.
Collapse
Affiliation(s)
- Claudia G Vasquez
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
| | - Mike Tworoger
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
| | - Adam C Martin
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142
| |
Collapse
|
44
|
Nie J, Mahato S, Zelhof AC. The actomyosin machinery is required for Drosophila retinal lumen formation. PLoS Genet 2014; 10:e1004608. [PMID: 25233220 PMCID: PMC4168998 DOI: 10.1371/journal.pgen.1004608] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 07/15/2014] [Indexed: 12/13/2022] Open
Abstract
Multicellular tubes consist of polarized cells wrapped around a central lumen and are essential structures underlying many developmental and physiological functions. In Drosophila compound eyes, each ommatidium forms a luminal matrix, the inter-rhabdomeral space, to shape and separate the key phototransduction organelles, the rhabdomeres, for proper visual perception. In an enhancer screen to define mechanisms of retina lumen formation, we identified Actin5C as a key molecule. Our results demonstrate that the disruption of lumen formation upon the reduction of Actin5C is not linked to any discernible defect in microvillus formation, the rhabdomere terminal web (RTW), or the overall morphogenesis and basal extension of the rhabdomere. Second, the failure of proper lumen formation is not the result of previously identified processes of retinal lumen formation: Prominin localization, expansion of the apical membrane, or secretion of the luminal matrix. Rather, the phenotype observed with Actin5C is phenocopied upon the decrease of the individual components of non-muscle myosin II (MyoII) and its upstream activators. In photoreceptor cells MyoII localizes to the base of the rhabdomeres, overlapping with the actin filaments of the RTW. Consistent with the well-established roll of actomyosin-mediated cellular contraction, reduction of MyoII results in reduced distance between apical membranes as measured by a decrease in lumen diameter. Together, our results indicate the actomyosin machinery coordinates with the localization of apical membrane components and the secretion of an extracellular matrix to overcome apical membrane adhesion to initiate and expand the retinal lumen. Biological tubes are integral units of tissues and organs such as lung, kidney, and the cardiovascular system. The fundamental design of tubes involves a central lumen wrapped by a sheet of cells. To function properly, the tubes require a precise genetic control over their creation, the diametric growth and maintenance of the lumen during development. In the fruit fly, Drosophila melanogaster, the photoreceptor cells of the eye form a tubular structure. The formation of the retinal lumen is critical for separating and positioning the light sensing organelles of each photoreceptor cell to achieve visual sensitivity. In an effort to investigate the mechanisms of Drosophila retinal lumen formation, we identified a contractile machinery that was present at the apical portion of photoreceptor cells. Our data is consistent with the idea that a contractile force contributes to the initial separation of the juxtaposed apical membranes and subsequent enlargement of the luminal space. Our work suggests that building a biological tube requires not only an extrinsic pushing force provided by the growing central lumen, but also a cell intrinsic pulling force powered by contraction of cells lining the lumen. Our findings expand and demonstrate the coordination of several molecular mechanisms to generate a tube.
Collapse
Affiliation(s)
- Jing Nie
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Simpla Mahato
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
| | - Andrew C. Zelhof
- Department of Biology, Indiana University, Bloomington, Indiana, United States of America
- * E-mail:
| |
Collapse
|
45
|
Spatiotemporal control of epithelial remodeling by regulated myosin phosphorylation. Proc Natl Acad Sci U S A 2014; 111:11732-7. [PMID: 25071215 DOI: 10.1073/pnas.1400520111] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Spatiotemporally regulated actomyosin contractility generates the forces that drive epithelial cell rearrangements and tissue remodeling. Phosphorylation of the myosin II regulatory light chain (RLC) promotes the assembly of myosin monomers into active contractile filaments and is an essential mechanism regulating the level of myosin activity. However, the effects of phosphorylation on myosin localization, dynamics, and function during epithelial remodeling are not well understood. In Drosophila, planar polarized myosin contractility is required for oriented cell rearrangements during elongation of the body axis. We show that regulated myosin phosphorylation influences spatial and temporal properties of contractile behavior at molecular, cellular, and tissue length scales. Expression of myosin RLC variants that prevent or mimic phosphorylation both disrupt axis elongation, but have distinct effects at the molecular and cellular levels. Unphosphorylatable RLC produces fewer, slower cell rearrangements, whereas phosphomimetic RLC accelerates rearrangement and promotes higher-order cell interactions. Quantitative live imaging and biophysical approaches reveal that both phosphovariants reduce myosin planar polarity and mechanical anisotropy, altering the orientation of cell rearrangements during axis elongation. Moreover, the localized myosin activator Rho-kinase is required for spatially regulated myosin activity, even when the requirement for phosphorylation is bypassed by the expression of phosphomimetic myosin RLC. These results indicate that myosin phosphorylation influences both the level and the spatiotemporal regulation of myosin activity, linking molecular properties of myosin activity to tissue morphogenesis.
Collapse
|
46
|
A spindle-independent cleavage pathway controls germ cell formation in Drosophila. Nat Cell Biol 2013; 15:839-45. [PMID: 23728423 PMCID: PMC3818562 DOI: 10.1038/ncb2761] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 04/16/2013] [Indexed: 01/08/2023]
Abstract
The primordial germ cells (PGCs) are the first cells to form during Drosophila melanogaster embryogenesis. While the process of somatic cell formation has been studied in detail, the mechanics of PGC formation are poorly understood. Here, using 4D multi-photon imaging combined with genetic and pharmacological manipulations, we find that PGC formation requires an anaphase spindle-independent cleavage pathway. In addition to utilizing core regulators of cleavage, including the small GTPase RhoA (Drosophila Rho) and the Rho associated kinase, ROCK (Drosophila Rok), we show that this pathway requires Germ cell-less (Gcl), a conserved BTB-domain protein not previously implicated in cleavage mechanics. This alternate form of cell formation suggests that organisms have evolved multiple molecular strategies for regulating the cytoskeleton during cleavage.
Collapse
|
47
|
De Storme N, De Schrijver J, Van Criekinge W, Wewer V, Dörmann P, Geelen D. GLUCAN SYNTHASE-LIKE8 and STEROL METHYLTRANSFERASE2 are required for ploidy consistency of the sexual reproduction system in Arabidopsis. THE PLANT CELL 2013; 25:387-403. [PMID: 23404886 PMCID: PMC3608767 DOI: 10.1105/tpc.112.106278] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2012] [Revised: 12/17/2012] [Accepted: 01/21/2013] [Indexed: 05/18/2023]
Abstract
In sexually reproducing plants, the meiocyte-producing archesporal cell lineage is maintained at the diploid state to consolidate the formation of haploid gametes. In search of molecular factors that regulate this ploidy consistency, we isolated an Arabidopsis thaliana mutant, called enlarged tetrad2 (et2), which produces tetraploid meiocytes through the stochastic occurrence of premeiotic endomitosis. Endomitotic polyploidization events were induced by alterations in cell wall formation, and similar cytokinetic defects were sporadically observed in other tissues, including cotyledons and leaves. ET2 encodes GLUCAN SYNTHASE-LIKE8 (GSL8), a callose synthase that mediates the deposition of callose at developing cell plates, root hairs, and plasmodesmata. Unlike other gsl8 mutants, in which defects in cell plate formation are seedling lethal, cytokinetic defects in et2 predominantly occur in flowers and have little effect on vegetative growth and development. Similarly, mutations in STEROL METHYLTRANSFERASE2 (SMT2), a major sterol biosynthesis enzyme, also lead to weak cytokinetic defects, primarily in the flowers. In addition, SMT2 allelic mutants also generate tetraploid meiocytes through the ectopic induction of premeiotic endomitosis. These observations demonstrate that appropriate callose and sterol biosynthesis are required for maintaining the ploidy level of the premeiotic germ lineage and that subtle defects in cytokinesis may lead to diploid gametes and polyploid offspring.
Collapse
Affiliation(s)
- Nico De Storme
- In Vitro Biology and Horticulture, Department of Plant Production, University of Ghent, 9000 Ghent, Belgium
| | - Joachim De Schrijver
- Bioinformatics and Computational Genomics (BIOBIX), Department of Molecular Biotechnology, University of Ghent, 9000 Ghent, Belgium
| | - Wim Van Criekinge
- Bioinformatics and Computational Genomics (BIOBIX), Department of Molecular Biotechnology, University of Ghent, 9000 Ghent, Belgium
| | - Vera Wewer
- Institute of Molecular Physiology and Biotechnology of Plants, University of Bonn, 53115 Bonn, Germany
| | - Peter Dörmann
- Institute of Molecular Physiology and Biotechnology of Plants, University of Bonn, 53115 Bonn, Germany
| | - Danny Geelen
- In Vitro Biology and Horticulture, Department of Plant Production, University of Ghent, 9000 Ghent, Belgium
- Address correspondence to
| |
Collapse
|
48
|
Röper K. Anisotropy of Crumbs and aPKC drives myosin cable assembly during tube formation. Dev Cell 2013; 23:939-53. [PMID: 23153493 PMCID: PMC3562440 DOI: 10.1016/j.devcel.2012.09.013] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 07/13/2012] [Accepted: 09/18/2012] [Indexed: 12/21/2022]
Abstract
The formation of tubular structures from epithelial sheets is a key process of organ formation in all animals, but the cytoskeletal rearrangements that cause the cell shape changes that drive tubulogenesis are not well understood. Using live imaging and super-resolution microscopy to analyze the tubulogenesis of the Drosophila salivary glands, I find that an anisotropic plasma membrane distribution of the protein Crumbs, mediated by its large extracellular domain, determines the subcellular localization of a supracellular actomyosin cable in the cells at the placode border, with myosin II accumulating at edges where Crumbs is lowest. Laser ablation shows that the cable is under increased tension, implying an active involvement in the invagination process. Crumbs anisotropy leads to anisotropic distribution of aPKC, which in turn can negatively regulate Rok, thus preventing the formation of a cable where Crumbs and aPKC are localized.
Collapse
Affiliation(s)
- Katja Röper
- MRC-Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.
| |
Collapse
|
49
|
Aldaz S, Escudero LM, Freeman M. Dual role of myosin II during Drosophila imaginal disc metamorphosis. Nat Commun 2013; 4:1761. [PMID: 23612302 PMCID: PMC3736102 DOI: 10.1038/ncomms2763] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 03/18/2013] [Indexed: 11/23/2022] Open
Abstract
The motor protein non-muscle myosin II is a major driver of the movements that sculpt three-dimensional organs from two-dimensional epithelia. The machinery of morphogenesis is well established but the logic of its control remains unclear in complex organs. Here we use live imaging and ex vivo culture to report a dual role of myosin II in regulating the development of the Drosophila wing. First, myosin II drives the contraction of a ring of cells that surround the squamous peripodial epithelium, providing the force to fold the whole disc through about 90°. Second, myosin II is needed to allow the squamous cells to expand and then retract at the end of eversion. The combination of genetics and live imaging allows us to describe and understand the tissue dynamics, and the logic of force generation needed to transform a relatively simple imaginal disc into a more complex and three-dimensional adult wing.
Collapse
|
50
|
Külshammer E, Uhlirova M. The actin cross-linker Filamin/Cheerio mediates tumor malignancy downstream of JNK signaling. J Cell Sci 2012; 126:927-38. [PMID: 23239028 DOI: 10.1242/jcs.114462] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Cell shape dynamics, motility, and cell proliferation all depend on the actin cytoskeleton. Malignant cancer cells hijack the actin network to grow and migrate to secondary sites. Understanding the function of actin regulators is therefore of major interest. In the present study, we identify the actin cross-linking protein Filamin/Cheerio (Cher) as a mediator of malignancy in genetically defined Drosophila tumors. We show that in invasive tumors, resulting from cooperation of activated Ras with disrupted epithelial cell polarity, Cher is upregulated in a Jun N-terminal kinase (JNK)-dependent manner. Although dispensable in normal epithelium, Cher becomes required in the tumor cells for their growth and invasiveness. When deprived of Cher, these tumor clones lose their full potential to proliferate and breach tissue boundaries. Instead, the Cher-deficient clones remain confined within the limits of their source epithelium, permitting survival of the host animal. Through interaction with the myosin II heavy chain subunit, Cher is likely to strengthen the cortical actomyosin network and reinforce mechanical tension within the invasive tumors. Accordingly, Cher is required for aberrant expression of genes downstream of the Hippo/Yorkie signaling in the tumor tissue. Our study identifies Cher as a new target of JNK signaling that links cytoskeleton dynamics to tumor progression.
Collapse
Affiliation(s)
- Eva Külshammer
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50674 Cologne, Germany
| | | |
Collapse
|