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Morton GM, Toledo MP, Zheng Y, Zheng C, Megraw TL. A distinct isoform of Msp300/Nesprin organizes the perinuclear microtubule organizing center in adipose cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.28.601268. [PMID: 38979285 PMCID: PMC11230431 DOI: 10.1101/2024.06.28.601268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
In many cell types, disparate non-centrosomal microtubule-organizing centers (ncMTOCs) replace functional centrosomes and serve the unique needs of the cell types in which they are formed. In Drosophila fat body cells (adipocytes), an ncMTOC is organized on the nuclear surface. This perinuclear ncMTOC is anchored by Msp300, encoded by one of two Nesprin-encoding genes in Drosophila. Msp300 and the spectraplakin short stop (shot) are co-dependent for localization to the nuclear envelope to generate the ncMTOC where they recruit the microtubule minus-end stabilizer Patronin (CAMSAP). The fat body perinuclear ncMTOC requires Patronin, Ninein, and Msps (ortholog of ch-TOG), but does not require γ-tubulin for MT assembly. The Msp300 gene is complex, encoding at least eleven isoforms. Here we show that two Msp300 isoforms, Msp300-PE and -PG, are required and only one, Msp300-PE, appears sufficient for generation of the ncMTOC. Loss of Msp300-PE,-PG retains the presence of the other isoforms at the nuclear surface, indicating that they are not sufficient to generate the ncMTOC. Loss of Msp300-PE,-PG results in severe loss of localization of shot and Patronin, and disruption of the MT array. This results in nuclear mispositioning and loss of endosomal trafficking. Msp300-PE has an unusual domain structure including a lack of a KASH domain and very few spectrin repeats and appears therefore to have a highly derived function suited to generating an ncMTOC on the nuclear surface.
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Affiliation(s)
- Garret M Morton
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA
| | - Maria Pilar Toledo
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA
| | - Yiming Zheng
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Faculty of Medicine and Life Sciences, Xiang'an Hospital of Xiamen University, Xiamen University, Xiamen, China, 361102, and Shenzhen Research Institute of Xiamen University, Shenzhen, China, 518057
| | - Chunfeng Zheng
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA
| | - Timothy L Megraw
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL, USA
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2
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Lepesant JA, Roland-Gosselin F, Guillemet C, Bernard F, Guichet A. The Importance of the Position of the Nucleus in Drosophila Oocyte Development. Cells 2024; 13:201. [PMID: 38275826 PMCID: PMC10814754 DOI: 10.3390/cells13020201] [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: 11/22/2023] [Revised: 01/12/2024] [Accepted: 01/16/2024] [Indexed: 01/27/2024] Open
Abstract
Oogenesis is a developmental process leading to the formation of an oocyte, a haploid gamete, which upon fertilisation and sperm entry allows the male and the female pronuclei to fuse and give rise to a zygote. In addition to forming a haploid gamete, oogenesis builds up a store of proteins, mRNAs, and organelles in the oocyte needed for the development of the future embryo. In several species, such as Drosophila, the polarity axes determinants of the future embryo must be asymmetrically distributed prior to fertilisation. In the Drosophila oocyte, the correct positioning of the nucleus is essential for establishing the dorsoventral polarity axis of the future embryo and allowing the meiotic spindles to be positioned in close vicinity to the unique sperm entry point into the oocyte.
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Affiliation(s)
| | | | | | | | - Antoine Guichet
- Université Paris Cité, CNRS, Institut Jacques Monod, 75013 Paris, France; (J.-A.L.); (F.R.-G.); (C.G.); (F.B.)
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3
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Guan C, Hua S, Jiang K. The CEP170B-KIF2A complex destabilizes microtubule minus ends to generate polarized microtubule network. EMBO J 2023; 42:e112953. [PMID: 37014312 PMCID: PMC10233374 DOI: 10.15252/embj.2022112953] [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: 10/28/2022] [Revised: 03/16/2023] [Accepted: 03/22/2023] [Indexed: 04/05/2023] Open
Abstract
Microtubule (MT) minus ends are stabilized by CAMSAP family proteins at noncentrosomal MT-organizing centers. Despite progress in identifying diverse positive regulators, knowledge on the negative regulation of the MT minus-end distribution is lacking. Here, we identify CEP170B as a MT minus-end-binding protein that colocalizes with the microtubule-stabilizing complex at the cortical patches. CEP170B depends on the scaffold protein liprin-α1 for its cortical targeting and requires liprin-α1-bound PP2A phosphatase for its MT localization. CEP170B excludes CAMSAPs-stabilized MT minus ends from the cell periphery in HeLa cells and the basal cortex in human epithelial cells and is required for directional vesicle trafficking and cyst formation in 3D culture. Reconstitution experiments demonstrate that CEP170B autonomously tracks growing MT minus ends and blocks minus-end growth. Furthermore, CEP170B in a complex with the kinesin KIF2A acts as a potent MT minus-end depolymerase capable of antagonizing the stabilizing effect of CAMSAPs. Our study uncovers an antagonistic mechanism for controlling the spatial distribution of MT minus ends, which contributes to the establishment of polarized MT network and cell polarity.
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Affiliation(s)
- Cuirong Guan
- The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Medical Research InstituteWuhan UniversityWuhanChina
- Frontier Science Center for Immunology and MetabolismWuhan UniversityWuhanChina
| | - Shasha Hua
- The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Medical Research InstituteWuhan UniversityWuhanChina
- Frontier Science Center for Immunology and MetabolismWuhan UniversityWuhanChina
| | - Kai Jiang
- The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Medical Research InstituteWuhan UniversityWuhanChina
- Frontier Science Center for Immunology and MetabolismWuhan UniversityWuhanChina
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4
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Lei Y, Huang Y, Yang K, Cao X, Song Y, Martín-Blanco E, Pastor-Pareja JC. FGF signaling promotes spreading of fat body precursors necessary for adult adipogenesis in Drosophila. PLoS Biol 2023; 21:e3002050. [PMID: 36947563 PMCID: PMC10069774 DOI: 10.1371/journal.pbio.3002050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 04/03/2023] [Accepted: 02/24/2023] [Indexed: 03/23/2023] Open
Abstract
Knowledge of adipogenetic mechanisms is essential to understand and treat conditions affecting organismal metabolism and adipose tissue health. In Drosophila, mature adipose tissue (fat body) exists in larvae and adults. In contrast to the well-known development of the larval fat body from the embryonic mesoderm, adult adipogenesis has remained mysterious. Furthermore, conclusive proof of its physiological significance is lacking. Here, we show that the adult fat body originates from a pool of undifferentiated mesodermal precursors that migrate from the thorax into the abdomen during metamorphosis. Through in vivo imaging, we found that these precursors spread from the ventral midline and cover the inner surface of the abdomen in a process strikingly reminiscent of embryonic mesoderm migration, requiring fibroblast growth factor (FGF) signaling as well. FGF signaling guides migration dorsally and regulates adhesion to the substrate. After spreading is complete, precursor differentiation involves fat accumulation and cell fusion that produces mature binucleate and tetranucleate adipocytes. Finally, we show that flies where adult adipogenesis is impaired by knock down of FGF receptor Heartless or transcription factor Serpent display ectopic fat accumulation in oenocytes and decreased resistance to starvation. Our results reveal that adult adipogenesis occurs de novo during metamorphosis and demonstrate its crucial physiological role.
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Affiliation(s)
- Yuting Lei
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Yuwei Huang
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Ke Yang
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Xueya Cao
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Yuzhao Song
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Enrique Martín-Blanco
- Instituto de Biología Molecular de Barcelona, Consejo Superior de Investigaciones Científicas, Parc Científic de Barcelona, Barcelona, Spain
| | - José Carlos Pastor-Pareja
- School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
- Institute of Neurosciences, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández, San Juan de Alicante, Spain
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5
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Shaw NM, Rios-Monterrosa JL, Fedorchak GR, Ketterer MR, Coombs GS, Lammerding J, Wallrath LL. Effects of mutant lamins on nucleo-cytoskeletal coupling in Drosophila models of LMNA muscular dystrophy. Front Cell Dev Biol 2022; 10:934586. [PMID: 36120560 PMCID: PMC9471154 DOI: 10.3389/fcell.2022.934586] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 07/20/2022] [Indexed: 11/13/2022] Open
Abstract
The nuclei of multinucleated skeletal muscles experience substantial external force during development and muscle contraction. Protection from such forces is partly provided by lamins, intermediate filaments that form a scaffold lining the inner nuclear membrane. Lamins play a myriad of roles, including maintenance of nuclear shape and stability, mediation of nuclear mechanoresponses, and nucleo-cytoskeletal coupling. Herein, we investigate how disease-causing mutant lamins alter myonuclear properties in response to mechanical force. This was accomplished via a novel application of a micropipette harpooning assay applied to larval body wall muscles of Drosophila models of lamin-associated muscular dystrophy. The assay enables the measurement of both nuclear deformability and intracellular force transmission between the cytoskeleton and nuclear interior in intact muscle fibers. Our studies revealed that specific mutant lamins increase nuclear deformability while other mutant lamins cause nucleo-cytoskeletal coupling defects, which were associated with loss of microtubular nuclear caging. We found that microtubule caging of the nucleus depended on Msp300, a KASH domain protein that is a component of the linker of nucleoskeleton and cytoskeleton (LINC) complex. Taken together, these findings identified residues in lamins required for connecting the nucleus to the cytoskeleton and suggest that not all muscle disease-causing mutant lamins produce similar defects in subcellular mechanics.
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Affiliation(s)
- Nicholas M. Shaw
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Jose L. Rios-Monterrosa
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Gregory R. Fedorchak
- The Nancy E. and Peter C. Meinig School of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, United States
| | - Margaret R. Ketterer
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Gary S. Coombs
- Biology Department, Waldorf University, Forest City, IA, United States
| | - Jan Lammerding
- The Nancy E. and Peter C. Meinig School of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, United States
| | - Lori L. Wallrath
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- *Correspondence: Lori L. Wallrath,
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6
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Nadkarni AV, Heald R. Reconstitution of muscle cell microtubule organization in vitro. Cytoskeleton (Hoboken) 2022; 78:492-502. [PMID: 35666041 DOI: 10.1002/cm.21710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 05/31/2022] [Accepted: 06/01/2022] [Indexed: 11/06/2022]
Abstract
Skeletal muscle differentiation occurs as muscle precursor cells (myoblasts) elongate and fuse to form multinucleated syncytial myotubes in which the highly-organized actomyosin sarcomeres of muscle fibers assemble. Although less well characterized, the microtubule cytoskeleton also undergoes dramatic rearrangement during myogenesis. The centrosome-nucleated microtubule array found in myoblasts is lost as the nuclear membrane acquires microtubule nucleating activity and microtubules emerge from multiple sites in the cell, eventually rearranging into a grid-like pattern in myotubes. In order to characterize perinuclear microtubule organization using a biochemically tractable system, we isolated nuclei from mouse C2C12 skeletal muscle cells during the course of differentiation and incubated them in cytoplasmic extracts prepared from eggs of the frog Xenopus laevis. Whereas centrosomes associated with myoblast nuclei gave rise to radial microtubule arrays in extracts, myotube nuclei produced a sun-like pattern with microtubules transiently nucleating from the entire nuclear envelope. Perinuclear microtubule growth was suppressed by inhibition of Aurora A kinase or by degradation of RNA, treatments that also inhibited microtubule growth from sperm centrosomes. Myotube nuclei displayed microtubule motor-based movements leading to their separation, as occurs in myotubes. This in vitro assay therefore recapitulates key features of microtubule organization and nuclear movement observed during muscle cell differentiation. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Ambika V Nadkarni
- Department of Molecular & Cell Biology, University of California, Berkeley, CA, USA
| | - Rebecca Heald
- Department of Molecular & Cell Biology, University of California, Berkeley, CA, USA
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7
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Kong X, Chen X, Ou S, Wang W, Li R. Derivation of human triploid trophoblast stem cells. J Assist Reprod Genet 2022; 39:1183-1193. [PMID: 35243570 PMCID: PMC9107551 DOI: 10.1007/s10815-022-02436-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
PURPOSE Human trophoblast stem cells (hTSCs) are counterparts of the precursor cells of the placenta and are valuable cell models for the study of placental development and the pathogenesis of placental diseases. The aim of this work was to establish a triploid human TSC (hTSC3PN) derived from the tripronuclear embryos, which are clinically discarded but readily available, for potential applications in basic placental research and disease modeling. METHODS Eighteen tripronuclear human zygotes from IVF were collected and cultured for 5-6 days. Five high-quality blastocysts were harvested and were individually cultured in hTSC medium. Finally, two hTSC lines were established after 10 days and could be passaged stably. RESULTS The karyotyping analysis showed that hTSC3PN contained three sets of chromosomes. And the hTSC3PN exhibited typical features of hTSCs, with the ability to differentiate into two trophoblast lineages: extravillous cytotrophoblasts (EVTs) and syncytiotrophoblasts (STs). In addition, the hTSC3PN can mimic some vital features of trophoblast, including hormone secretion and invasion. Further studies showed that the proliferation and differentiation of hTSC3PN were reduced compared with normal hTSCs, which may be related to the disturbed metabolic signaling in hTSC3PN. CONCLUSIONS We established the triploid hTSC lines derived from tripronuclear embryos, which provides a potentially useful research model in vitro to study human placental biology and diseases.
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Affiliation(s)
- Xuhui Kong
- Department of Histology and Embryology, Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Xin Chen
- Department of Histology and Embryology, Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Songbang Ou
- Reproductive Medicine Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Guangzhou, China
| | - Wenjun Wang
- Reproductive Medicine Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China. .,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Guangzhou, China.
| | - Ruiqi Li
- Reproductive Medicine Center, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China. .,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Guangzhou, China. .,Reproductive Medicine Center, The First People's Hospital of Kashgar, Kashgar, China.
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8
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Zhao AJ, Montes-Laing J, Perry WMG, Shiratori M, Merfeld E, Rogers SL, Applewhite DA. The Drosophila spectraplakin Short stop regulates focal adhesion dynamics by crosslinking microtubules and actin. Mol Biol Cell 2022; 33:ar19. [PMID: 35235367 PMCID: PMC9282009 DOI: 10.1091/mbc.e21-09-0434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The spectraplakin family of proteins includes ACF7/MACF1 and BPAG1/dystonin in mammals, VAB-10 in Caenorhabditis elegans, Magellan in zebrafish, and Short stop (Shot), the sole Drosophila member. Spectraplakins are giant cytoskeletal proteins that cross-link actin, microtubules, and intermediate filaments, coordinating the activity of the entire cytoskeleton. We examined the role of Shot during cell migration using two systems: the in vitro migration of Drosophila tissue culture cells and in vivo through border cell migration. RNA interference (RNAi) depletion of Shot increases the rate of random cell migration in Drosophila tissue culture cells as well as the rate of wound closure during scratch-wound assays. This increase in cell migration prompted us to analyze focal adhesion dynamics. We found that the rates of focal adhesion assembly and disassembly were faster in Shot-depleted cells, leading to faster adhesion turnover that could underlie the increased migration speeds. This regulation of focal adhesion dynamics may be dependent on Shot being in an open confirmation. Using Drosophila border cells as an in vivo model for cell migration, we found that RNAi depletion led to precocious border cell migration. Collectively, these results suggest that spectraplakins not only function to cross-link the cytoskeleton but may regulate cell–matrix adhesion.
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Affiliation(s)
- Andrew J Zhao
- Department of Biology, Reed College, 3203 SE Woodstock Boulevard, Portland, OR 97202, USA
| | - Julia Montes-Laing
- Department of Biology, Reed College, 3203 SE Woodstock Boulevard, Portland, OR 97202, USA
| | - Wick M G Perry
- Department of Biology, Reed College, 3203 SE Woodstock Boulevard, Portland, OR 97202, USA
| | - Mari Shiratori
- Department of Biology, Reed College, 3203 SE Woodstock Boulevard, Portland, OR 97202, USA
| | - Emily Merfeld
- Department of Biology, Reed College, 3203 SE Woodstock Boulevard, Portland, OR 97202, USA
| | - Stephen L Rogers
- Department of Biology & Carolina Center for Genome Sciences, The University of North Carolina at Chapel Hill, Campus Box 3280, 422 Fordham Hall, Chapel Hill, NC 27599-3280, USA
| | - Derek A Applewhite
- Department of Biology, Reed College, 3203 SE Woodstock Boulevard, Portland, OR 97202, USA
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9
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Hawdon A, Aberkane A, Zenker J. Microtubule-dependent subcellular organisation of pluripotent cells. Development 2021; 148:272646. [PMID: 34710215 DOI: 10.1242/dev.199909] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
With the advancement of cutting-edge live imaging technologies, microtubule remodelling has evolved as an integral regulator for the establishment of distinct differentiated cells. However, despite their fundamental role in cell structure and function, microtubules have received less attention when unravelling the regulatory circuitry of pluripotency. Here, we summarise the role of microtubule organisation and microtubule-dependent events required for the formation of pluripotent cells in vivo by deciphering the process of early embryogenesis: from fertilisation to blastocyst. Furthermore, we highlight current advances in elucidating the significance of specific microtubule arrays in in vitro culture systems of pluripotent stem cells and how the microtubule cytoskeleton serves as a highway for the precise intracellular movement of organelles. This Review provides an informed understanding of the intrinsic role of subcellular architecture of pluripotent cells and accentuates their regenerative potential in combination with innovative light-inducible microtubule techniques.
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Affiliation(s)
- Azelle Hawdon
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Asma Aberkane
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria 3800, Australia
| | - Jennifer Zenker
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria 3800, Australia
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10
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Atypical laminin spots and pull-generated microtubule-actin projections mediate Drosophila wing adhesion. Cell Rep 2021; 36:109667. [PMID: 34496252 DOI: 10.1016/j.celrep.2021.109667] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 06/11/2021] [Accepted: 08/13/2021] [Indexed: 12/12/2022] Open
Abstract
During Drosophila metamorphosis, dorsal and ventral wing surfaces adhere, separate, and reappose in a paradoxical process involving cell-matrix adhesion, matrix production and degradation, and long cellular projections. The identity of the intervening matrix, the logic behind the adhesion-reapposition cycle, and the role of projections are unknown. We find that laminin matrix spots devoid of other main basement membrane components mediate wing adhesion. Through live imaging, we show that long microtubule-actin cables grow from those adhesion spots because of hydrostatic pressure that pushes wing surfaces apart. Formation of cables resistant to pressure requires spectraplakin, Patronin, septins, and Sdb, a SAXO1/2 microtubule stabilizer expressed under control of wing intervein-selector SRF. Silkworms and dead-leaf butterflies display similar dorso-ventral projections and expression of Sdb in intervein SRF-like patterns. Our study supports the morphogenetic importance of atypical basement-membrane-related matrices and dissects matrix-cytoskeleton coordination in a process of great evolutionary significance.
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11
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Bu S, Yong WL, Lim BJW, Kondo S, Yu F. A systematic analysis of microtubule-destabilizing factors during dendrite pruning in Drosophila. EMBO Rep 2021; 22:e52679. [PMID: 34338441 DOI: 10.15252/embr.202152679] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 07/10/2021] [Accepted: 07/12/2021] [Indexed: 11/09/2022] Open
Abstract
It has long been thought that microtubule disassembly, one of the earliest cellular events, contributes to neuronal pruning and neurodegeneration in development and disease. However, how microtubule disassembly drives neuronal pruning remains poorly understood. Here, we conduct a systematic investigation of various microtubule-destabilizing factors and identify exchange factor for Arf6 (Efa6) and Stathmin (Stai) as new regulators of dendrite pruning in ddaC sensory neurons during Drosophila metamorphosis. We show that Efa6 is both necessary and sufficient to regulate dendrite pruning. Interestingly, Efa6 and Stai facilitate microtubule turnover and disassembly prior to dendrite pruning without compromising the minus-end-out microtubule orientation in dendrites. Moreover, our pharmacological and genetic manipulations strongly support a key role of microtubule disassembly in promoting dendrite pruning. Thus, this systematic study highlights the importance of two selective microtubule destabilizers in dendrite pruning and substantiates a causal link between microtubule disassembly and neuronal pruning.
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Affiliation(s)
- Shufeng Bu
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Wei Lin Yong
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore
| | - Bryan Jian Wei Lim
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore, Singapore
| | - Shu Kondo
- Invertebrate Genetics Laboratory, National Institute of Genetics, Shizuoka, Japan
| | - Fengwei Yu
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore, Singapore
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12
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Lu W, Lakonishok M, Gelfand VI. Gatekeeper function for Short stop at the ring canals of the Drosophila ovary. Curr Biol 2021; 31:3207-3220.e4. [PMID: 34089646 DOI: 10.1016/j.cub.2021.05.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 03/15/2021] [Accepted: 05/04/2021] [Indexed: 02/06/2023]
Abstract
Growth of the Drosophila oocyte requires transport of cytoplasmic materials from the interconnected sister cells (nurse cells) through ring canals, the cytoplasmic bridges that remained open after incomplete germ cell division. Given the open nature of the ring canals, it is unclear how the direction of transport through the ring canal is controlled. In this work, we show that a single Drosophila spectraplakin Short stop (Shot) controls the direction of flow from nurse cells to the oocyte. Knockdown of shot changes the direction of transport through the ring canals from unidirectional (toward the oocyte) to bidirectional. After shot knockdown, the oocyte stops growing, resulting in a characteristic small oocyte phenotype. In agreement with this transport-directing function of Shot, we find that it is localized at the asymmetric actin baskets on the nurse cell side of the ring canals. In wild-type egg chambers, microtubules localized in the ring canals have uniform polarity (minus ends toward the oocyte), while in the absence of Shot, these microtubules have mixed polarity. Together, we propose that Shot functions as a gatekeeper directing transport from nurse cells to the oocyte via the organization of microtubule tracks to facilitate the transport driven by the minus-end-directed microtubule motor cytoplasmic dynein. VIDEO ABSTRACT.
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Affiliation(s)
- Wen Lu
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Margot Lakonishok
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Vladimir I Gelfand
- Department of Cell and Developmental Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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13
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Sun L, Cui L, Liu Z, Wang Q, Xue Z, Wu M, Sun T, Mao D, Ni J, Pastor-Pareja JC, Liang X. Katanin p60-like 1 sculpts the cytoskeleton in mechanosensory cilia. J Cell Biol 2021; 220:211570. [PMID: 33263729 PMCID: PMC7717695 DOI: 10.1083/jcb.202004184] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 09/28/2020] [Accepted: 10/20/2020] [Indexed: 12/20/2022] Open
Abstract
Mechanoreceptor cells develop a specialized cytoskeleton that plays structural and sensory roles at the site of mechanotransduction. However, little is known about how the cytoskeleton is organized and formed. Using electron tomography and live-cell imaging, we resolve the 3D structure and dynamics of the microtubule-based cytoskeleton in fly campaniform mechanosensory cilia. Investigating the formation of the cytoskeleton, we find that katanin p60-like 1 (kat-60L1), a neuronal type of microtubule-severing enzyme, serves two functions. First, it amplifies the mass of microtubules to form the dense microtubule arrays inside the sensory cilia. Second, it generates short microtubules that are required to build the nanoscopic cytoskeleton at the mechanotransduction site. Additional analyses further reveal the functional roles of Patronin and other potential factors in the local regulatory network. In all, our results characterize the specialized cytoskeleton in fly external mechanosensory cilia at near-molecular resolution and provide mechanistic insights into how it is formed.
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Affiliation(s)
- Landi Sun
- Tsinghua-Peking Joint Center for Life Science, School of Life Sciences, Tsinghua University, Beijing, China
| | - Lihong Cui
- Tsinghua-Peking Joint Center for Life Science, School of Life Sciences, Tsinghua University, Beijing, China
| | - Zhen Liu
- Tsinghua-Peking Joint Center for Life Science, School of Life Sciences, Tsinghua University, Beijing, China
| | - Qixuan Wang
- Tsinghua-Peking Joint Center for Life Science, School of Life Sciences, Tsinghua University, Beijing, China
| | - Zhaoyu Xue
- Tsinghua-Peking Joint Center for Life Science, School of Life Sciences, Tsinghua University, Beijing, China
| | - Menghua Wu
- Tsinghua-Peking Joint Center for Life Science, School of Life Sciences, Tsinghua University, Beijing, China
| | - Tianhui Sun
- Tsinghua-Peking Joint Center for Life Science, School of Life Sciences, Tsinghua University, Beijing, China
| | - Decai Mao
- School of Medicine, Tsinghua University, Beijing, China
| | - Jianquan Ni
- School of Medicine, Tsinghua University, Beijing, China
| | - José Carlos Pastor-Pareja
- Tsinghua-Peking Joint Center for Life Science, School of Life Sciences, Tsinghua University, Beijing, China
| | - Xin Liang
- Tsinghua-Peking Joint Center for Life Science, School of Life Sciences, Tsinghua University, Beijing, China
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14
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Feng Z, Yang K, Pastor-Pareja JC. Tales of the ER-Golgi Frontier: Drosophila-Centric Considerations on Tango1 Function. Front Cell Dev Biol 2021; 8:619022. [PMID: 33505971 PMCID: PMC7829582 DOI: 10.3389/fcell.2020.619022] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 12/14/2020] [Indexed: 12/15/2022] Open
Abstract
In the secretory pathway, the transfer of cargo from the ER to the Golgi involves dozens of proteins that localize at specific regions of the ER called ER exit sites (ERES), where cargos are concentrated preceding vesicular transport to the Golgi. Despite many years of research, we are missing crucial details of how this highly dynamic ER-Golgi interface is defined, maintained and functions. Mechanisms allowing secretion of large cargos such as the very abundant collagens are also poorly understood. In this context, Tango1, discovered in the fruit fly Drosophila and widely conserved in animal evolution, has received a lot of attention in recent years. Tango1, an ERES-localized transmembrane protein, is the single fly member of the MIA/cTAGE family, consisting in humans of TANGO1 and at least 14 different related proteins. After its discovery in flies, a specific role of human TANGO1 in mediating secretion of collagens was reported. However, multiple studies in Drosophila have demonstrated that Tango1 is required for secretion of all cargos. At all ERES, through self-interaction and interactions with other proteins, Tango1 aids ERES maintenance and tethering of post-ER membranes. In this review, we discuss discoveries on Drosophila Tango1 and put them in relation with research on human MIA/cTAGE proteins. In doing so, we aim to offer an integrated view of Tango1 function and the nature of ER-Golgi transport from an evolutionary perspective.
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Affiliation(s)
- Zhi Feng
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Ke Yang
- School of Life Sciences, Tsinghua University, Beijing, China
| | - José C Pastor-Pareja
- School of Life Sciences, Tsinghua University, Beijing, China.,Tsinghua-Peking Center for Life Sciences, Beijing, China
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15
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Unnikannan CP, Reuveny A, Grunberg D, Volk T. Recruitment of BAF to the nuclear envelope couples the LINC complex to endoreplication. Development 2020; 147:dev.191304. [PMID: 33168584 PMCID: PMC7758627 DOI: 10.1242/dev.191304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 10/29/2020] [Indexed: 12/21/2022]
Abstract
DNA endoreplication has been implicated as a cell strategy for cell growth and in tissue injury. Here, we demonstrate that barrier-to-autointegration factor (BAF) represses endoreplication in Drosophila myofibers. We show that BAF localization at the nuclear envelope is eliminated in flies with mutations of the linker of nucleoskeleton and cytoskeleton (LINC) complex in which the LEM-domain protein Otefin is excluded, or after disruption of the nucleus-sarcomere connections. Furthermore, BAF localization at the nuclear envelope requires the activity of the BAF kinase VRK1/Ball, and, consistently, non-phosphorylatable BAF-GFP is excluded from the nuclear envelope. Importantly, removal of BAF from the nuclear envelope correlates with increased DNA content in the myonuclei. E2F1, a key regulator of endoreplication, overlaps BAF localization at the myonuclear envelope, and BAF removal from the nuclear envelope results in increased E2F1 levels in the nucleoplasm and subsequent elevated DNA content. We suggest that LINC-dependent and phosphosensitive attachment of BAF to the nuclear envelope, through its binding to Otefin, tethers E2F1 to the nuclear envelope thus inhibiting its accumulation in the nucleoplasm. Summary: Localization of BAF at the nuclear envelope of myonuclei depends on a functional LINC complex and on nucleus-sarcomere connections, and is shown to restrict E2F1 levels in the nucleoplasm.
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Affiliation(s)
- C P Unnikannan
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Adriana Reuveny
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Dvorah Grunberg
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Talila Volk
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
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16
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Ricolo D, Araujo SJ. Coordinated crosstalk between microtubules and actin by a spectraplakin regulates lumen formation and branching. eLife 2020; 9:61111. [PMID: 33112231 PMCID: PMC7661041 DOI: 10.7554/elife.61111] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 10/27/2020] [Indexed: 12/17/2022] Open
Abstract
Subcellular lumen formation by single-cells involves complex cytoskeletal remodelling. We have previously shown that centrosomes are key players in the initiation of subcellular lumen formation in Drosophila melanogaster, but not much is known on the what leads to the growth of these subcellular luminal branches or makes them progress through a particular trajectory within the cytoplasm. Here, we have identified that the spectraplakin Short-stop (Shot) promotes the crosstalk between MTs and actin, which leads to the extension and guidance of the subcellular lumen within the tracheal terminal cell (TC) cytoplasm. Shot is enriched in cells undergoing the initial steps of subcellular branching as a direct response to FGF signalling. An excess of Shot induces ectopic acentrosomal luminal branching points in the embryonic and larval tracheal TC leading to cells with extra-subcellular lumina. These data provide the first evidence for a role for spectraplakins in single-cell lumen formation and branching.
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Affiliation(s)
- Delia Ricolo
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, Barcelona, Spain.,Institute of Biomedicine University of Barcelona (IBUB), Barcelona, Spain
| | - Sofia J Araujo
- Department of Genetics, Microbiology and Statistics, School of Biology, University of Barcelona, Barcelona, Spain.,Institute of Biomedicine University of Barcelona (IBUB), Barcelona, Spain
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17
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Wesley CC, Mishra S, Levy DL. Organelle size scaling over embryonic development. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2020; 9:e376. [PMID: 32003549 DOI: 10.1002/wdev.376] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 12/19/2019] [Accepted: 01/08/2020] [Indexed: 12/13/2022]
Abstract
Cell division without growth results in progressive cell size reductions during early embryonic development. How do the sizes of intracellular structures and organelles scale with cell size and what are the functional implications of such scaling relationships? Model organisms, in particular Caenorhabditis elegans worms, Drosophila melanogaster flies, Xenopus laevis frogs, and Mus musculus mice, have provided insights into developmental size scaling of the nucleus, mitotic spindle, and chromosomes. Nuclear size is regulated by nucleocytoplasmic transport, nuclear envelope proteins, and the cytoskeleton. Regulators of microtubule dynamics and chromatin compaction modulate spindle and mitotic chromosome size scaling, respectively. Developmental scaling relationships for membrane-bound organelles, like the endoplasmic reticulum, Golgi, mitochondria, and lysosomes, have been less studied, although new imaging approaches promise to rectify this deficiency. While models that invoke limiting components and dynamic regulation of assembly and disassembly can account for some size scaling relationships in early embryos, it will be exciting to investigate the contribution of newer concepts in cell biology such as phase separation and interorganellar contacts. With a growing understanding of the underlying mechanisms of organelle size scaling, future studies promise to uncover the significance of proper scaling for cell function and embryonic development, as well as how aberrant scaling contributes to disease. This article is categorized under: Establishment of Spatial and Temporal Patterns > Regulation of Size, Proportion, and Timing Early Embryonic Development > Fertilization to Gastrulation Comparative Development and Evolution > Model Systems.
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Affiliation(s)
- Chase C Wesley
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming
| | - Sampada Mishra
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming
| | - Daniel L Levy
- Department of Molecular Biology, University of Wyoming, Laramie, Wyoming
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