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Wu J, Bala Tannan N, Vuong LT, Koca Y, Collu GM, Mlodzik M. Par3/bazooka binds NICD and promotes notch signaling during Drosophila development. Dev Biol 2024; 514:37-49. [PMID: 38885804 PMCID: PMC11287782 DOI: 10.1016/j.ydbio.2024.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 04/01/2024] [Accepted: 06/14/2024] [Indexed: 06/20/2024]
Abstract
The conserved bazooka (baz/par3) gene acts as a key regulator of asymmetrical cell divisions across the animal kingdom. Associated Par3/Baz-Par6-aPKC protein complexes are also well known for their role in the establishment of apical/basal cell polarity in epithelial cells. Here we define a novel, positive function of Baz/Par3 in the Notch pathway. Using Drosophila wing and eye development, we demonstrate that Baz is required for Notch signaling activity and optimal transcriptional activation of Notch target genes. Baz appears to act independently of aPKC in these contexts, as knockdown of aPKC does not cause Notch loss-of-function phenotypes. Using transgenic Notch constructs, our data positions Baz activity downstream of activating Notch cleavage steps and upstream of Su(H)/CSL transcription factor complex activity on Notch target genes. We demonstrate a biochemical interaction between NICD and Baz, suggesting that Baz is required for NICD activity before NICD binds to Su(H). Taken together, our data define a novel role of the polarity protein Baz/Par3, as a positive and direct regulator of Notch signaling through its interaction with NICD.
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Affiliation(s)
- Jun Wu
- Dept. of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
| | - Neeta Bala Tannan
- Dept. of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
| | - Linh T Vuong
- Dept. of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
| | - Yildiz Koca
- Dept. of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
| | - Giovanna M Collu
- Dept. of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA
| | - Marek Mlodzik
- Dept. of Cell, Developmental, and Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY, 10029, USA.
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2
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Hinsch CL, Venkata JK, Hsu T, Dammai V. Controlled Plasma Membrane Delivery of FGFR1 and Modulation of Signaling by a Novel Regulated Anterograde RTK Transport Pathway. Cancers (Basel) 2023; 15:5837. [PMID: 38136383 PMCID: PMC10741464 DOI: 10.3390/cancers15245837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 11/29/2023] [Accepted: 12/05/2023] [Indexed: 12/24/2023] Open
Abstract
How human FGFR1 localizes to the PM is unknown. Currently, it is assumed that newly synthesized FGFR1 is continuously delivered to the PM. However, evidence indicates that FGFR1 is mostly sequestered in intracellular post-Golgi vesicles (PGVs) under normal conditions. In this report, live-cell imaging and total internal reflection fluorescence microscopy (TIRFM) were employed to study the dynamics of these FGFR1-positive vesicles. We designed recombinant proteins to target different transport components to and from the FGFR1 vesicles. Mouse embryoid bodies (mEBs) were used as a 3D model system to confirm major findings. Briefly, we found that Rab2a, Rab6a, Rab8a, RalA and caveolins are integral components of FGFR1-positive vesicles, representing a novel compartment. While intracellular sequestration prevented FGFR1 activation, serum starvation and hypoxia stimulated PM localization of FGFR1. Under these conditions, FGFR1 C-terminus acts as a scaffold to assemble proteins to (i) inactivate Rab2a and release sequestration, and (ii) assemble Rab6a for localized activation of Rab8a and RalA-exocyst to deliver the receptor to the PM. This novel pathway is named Regulated Anterograde RTK Transport (RART). This is the first instance of RTK regulated through control of PM delivery.
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Affiliation(s)
- Claire Leist Hinsch
- Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29401, USA (J.K.V.)
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC 29401, USA
| | - Jagadish Kummetha Venkata
- Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29401, USA (J.K.V.)
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC 29401, USA
| | - Tien Hsu
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung 40433, Taiwan
| | - Vincent Dammai
- Aldevron LLC (Danaher Corporation), Fargo, ND 58104, USA
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3
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Zhao H, Shi L, Li Z, Kong R, Jia L, Lu S, Wang JH, Dong MQ, Guo X, Li Z. Diamond controls epithelial polarity through the dynactin-dynein complex. Traffic 2023; 24:552-563. [PMID: 37642208 DOI: 10.1111/tra.12917] [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: 02/13/2023] [Revised: 07/10/2023] [Accepted: 08/21/2023] [Indexed: 08/31/2023]
Abstract
Epithelial polarity is critical for proper functions of epithelial tissues, tumorigenesis, and metastasis. The evolutionarily conserved transmembrane protein Crumbs (Crb) is a key regulator of epithelial polarity. Both Crb protein and its transcripts are apically localized in epithelial cells. However, it remains not fully understood how they are targeted to the apical domain. Here, using Drosophila ovarian follicular epithelia as a model, we show that epithelial polarity is lost and Crb protein is absent in the apical domain in follicular cells (FCs) in the absence of Diamond (Dind). Interestingly, Dind is found to associate with different components of the dynactin-dynein complex through co-IP-MS analysis. Dind stabilizes dynactin and depletion of dynactin results in almost identical defects as those observed in dind-defective FCs. Finally, both Dind and dynactin are also required for the apical localization of crb transcripts in FCs. Thus our data illustrate that Dind functions through dynactin/dynein-mediated transport of both Crb protein and its transcripts to the apical domain to control epithelial apico-basal (A/B) polarity.
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Affiliation(s)
- Hang Zhao
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Lin Shi
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Zhengran Li
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Ruiyan Kong
- College of Life Sciences, Capital Normal University, Beijing, China
| | - Lemei Jia
- National Institute of Biological Sciences (NIBS), Beijing, China
| | - Shan Lu
- National Institute of Biological Sciences (NIBS), Beijing, China
| | - Jian-Hua Wang
- National Institute of Biological Sciences (NIBS), Beijing, China
| | - Meng-Qiu Dong
- National Institute of Biological Sciences (NIBS), Beijing, China
| | - Xuan Guo
- Life Science Institute, Jinzhou Medical University, Jinzhou, Liaoning, China
| | - Zhouhua Li
- College of Life Sciences, Capital Normal University, Beijing, China
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4
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Pereira C, Stalder D, Anderson GS, Shun-Shion AS, Houghton J, Antrobus R, Chapman MA, Fazakerley DJ, Gershlick DC. The exocyst complex is an essential component of the mammalian constitutive secretory pathway. J Cell Biol 2023; 222:e202205137. [PMID: 36920342 PMCID: PMC10041652 DOI: 10.1083/jcb.202205137] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 11/11/2022] [Accepted: 02/01/2023] [Indexed: 03/16/2023] Open
Abstract
Secreted proteins fulfill a vast array of functions, including immunity, signaling, and extracellular matrix remodeling. In the trans-Golgi network, proteins destined for constitutive secretion are sorted into post-Golgi carriers which fuse with the plasma membrane. The molecular machinery involved is poorly understood. Here, we have used kinetic trafficking assays and transient CRISPR-KO to study biosynthetic sorting from the Golgi to the plasma membrane. Depletion of all canonical exocyst subunits causes cargo accumulation in post-Golgi carriers. Exocyst subunits are recruited to and co-localize with carriers. Exocyst abrogation followed by kinetic trafficking assays of soluble cargoes results in intracellular cargo accumulation. Unbiased secretomics reveals impairment of soluble protein secretion after exocyst subunit knockout. Importantly, in specialized cell types, the loss of exocyst prevents constitutive secretion of antibodies in lymphocytes and of leptin in adipocytes. These data identify exocyst as the functional tether of secretory post-Golgi carriers at the plasma membrane and an essential component of the mammalian constitutive secretory pathway.
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Affiliation(s)
- Conceição Pereira
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Danièle Stalder
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | | | - Amber S. Shun-Shion
- Metabolic Research Laboratory, Wellcome-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Jack Houghton
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Robin Antrobus
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | | | - Daniel J. Fazakerley
- Metabolic Research Laboratory, Wellcome-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - David C. Gershlick
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
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5
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Bonello TT, Cai D, Fletcher GC, Wiengartner K, Pengilly V, Lange KS, Liu Z, Lippincott‐Schwartz J, Kavran JM, Thompson BJ. Phase separation of Hippo signalling complexes. EMBO J 2023; 42:e112863. [PMID: 36807601 PMCID: PMC10015380 DOI: 10.15252/embj.2022112863] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/12/2023] [Accepted: 01/23/2023] [Indexed: 02/22/2023] Open
Abstract
The Hippo pathway was originally discovered to control tissue growth in Drosophila and includes the Hippo kinase (Hpo; MST1/2 in mammals), scaffold protein Salvador (Sav; SAV1 in mammals) and the Warts kinase (Wts; LATS1/2 in mammals). The Hpo kinase is activated by binding to Crumbs-Expanded (Crb-Ex) and/or Merlin-Kibra (Mer-Kib) proteins at the apical domain of epithelial cells. Here we show that activation of Hpo also involves the formation of supramolecular complexes with properties of a biomolecular condensate, including concentration dependence and sensitivity to starvation, macromolecular crowding, or 1,6-hexanediol treatment. Overexpressing Ex or Kib induces formation of micron-scale Hpo condensates in the cytoplasm, rather than at the apical membrane. Several Hippo pathway components contain unstructured low-complexity domains and purified Hpo-Sav complexes undergo phase separation in vitro. Formation of Hpo condensates is conserved in human cells. We propose that apical Hpo kinase activation occurs in phase separated "signalosomes" induced by clustering of upstream pathway components.
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Affiliation(s)
- Teresa T Bonello
- EMBL Australia, John Curtin School of Medical ResearchAustralian National UniversityCanberraACTAustralia
| | - Danfeng Cai
- HHMI Janelia Research CampusAshburnVAUSA
- Department of Biochemistry and Molecular BiologyBloomberg School of Public HealthBaltimoreMDUSA
| | | | - Kyler Wiengartner
- Department of Biochemistry and Molecular BiologyBloomberg School of Public HealthBaltimoreMDUSA
| | - Victoria Pengilly
- EMBL Australia, John Curtin School of Medical ResearchAustralian National UniversityCanberraACTAustralia
| | - Kimberly S Lange
- Department of Biochemistry and Molecular BiologyBloomberg School of Public HealthBaltimoreMDUSA
| | - Zhe Liu
- HHMI Janelia Research CampusAshburnVAUSA
| | | | - Jennifer M Kavran
- Department of Biochemistry and Molecular BiologyBloomberg School of Public HealthBaltimoreMDUSA
- Department of Biophysics and Biophysical Chemistry, and Department of OncologyJohns Hopkins School of MedicineBaltimoreMDUSA
| | - Barry J Thompson
- EMBL Australia, John Curtin School of Medical ResearchAustralian National UniversityCanberraACTAustralia
- Epithelial Biology LaboratoryThe Francis Crick InstituteLondonUK
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6
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Swope RD, Hertzler JI, Stone MC, Kothe GO, Rolls MM. The exocyst complex is required for developmental and regenerative neurite growth in vivo. Dev Biol 2022; 492:1-13. [PMID: 36162553 PMCID: PMC10228574 DOI: 10.1016/j.ydbio.2022.09.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 09/13/2022] [Accepted: 09/19/2022] [Indexed: 11/30/2022]
Abstract
The exocyst complex is an important regulator of intracellular trafficking and tethers secretory vesicles to the plasma membrane. Understanding of its role in neuron outgrowth remains incomplete, and previous studies have come to different conclusions about its importance for axon and dendrite growth, particularly in vivo. To investigate exocyst function in vivo we used Drosophila sensory neurons as a model system. To bypass early developmental requirements in other cell types, we used neuron-specific RNAi to target seven exocyst subunits. Initial neuronal development proceeded normally in these backgrounds, however, we considered this could be due to residual exocyst function. To probe neuronal growth capacity at later times after RNAi initiation, we used laser microsurgery to remove axons or dendrites and prompt regrowth. Exocyst subunit RNAi reduced axon regeneration, although new axons could be specified. In control neurons, a vesicle trafficking marker often concentrated in the new axon, but this pattern was disrupted in Sec6 RNAi neurons. Dendrite regeneration was also severely reduced by exocyst RNAi, even though the trafficking marker did not accumulate in a strongly polarized manner during normal dendrite regeneration. The requirement for the exocyst was not limited to injury contexts as exocyst subunit RNAi eliminated dendrite regrowth after developmental pruning. We conclude that the exocyst is required for injury-induced and developmental neurite outgrowth, but that residual protein function can easily mask this requirement.
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Affiliation(s)
- Rachel D Swope
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, University Park, PA, 16802, USA
| | - J Ian Hertzler
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, University Park, PA, 16802, USA
| | - Michelle C Stone
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, University Park, PA, 16802, USA
| | - Gregory O Kothe
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, University Park, PA, 16802, USA
| | - Melissa M Rolls
- Biochemistry and Molecular Biology and the Huck Institutes of the Life Sciences, University Park, PA, 16802, USA.
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7
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Apical-basal polarity and the control of epithelial form and function. Nat Rev Mol Cell Biol 2022; 23:559-577. [PMID: 35440694 DOI: 10.1038/s41580-022-00465-y] [Citation(s) in RCA: 85] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2022] [Indexed: 02/02/2023]
Abstract
Epithelial cells are the most common cell type in all animals, forming the sheets and tubes that compose most organs and tissues. Apical-basal polarity is essential for epithelial cell form and function, as it determines the localization of the adhesion molecules that hold the cells together laterally and the occluding junctions that act as barriers to paracellular diffusion. Polarity must also target the secretion of specific cargoes to the apical, lateral or basal membranes and organize the cytoskeleton and internal architecture of the cell. Apical-basal polarity in many cells is established by conserved polarity factors that define the apical (Crumbs, Stardust/PALS1, aPKC, PAR-6 and CDC42), junctional (PAR-3) and lateral (Scribble, DLG, LGL, Yurt and RhoGAP19D) domains, although recent evidence indicates that not all epithelia polarize by the same mechanism. Research has begun to reveal the dynamic interactions between polarity factors and how they contribute to polarity establishment and maintenance. Elucidating these mechanisms is essential to better understand the roles of apical-basal polarity in morphogenesis and how defects in polarity contribute to diseases such as cancer.
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8
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Endocytosis at the Crossroad of Polarity and Signaling Regulation: Learning from Drosophila melanogaster and Beyond. Int J Mol Sci 2022; 23:ijms23094684. [PMID: 35563080 PMCID: PMC9101507 DOI: 10.3390/ijms23094684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 04/19/2022] [Accepted: 04/21/2022] [Indexed: 02/06/2023] Open
Abstract
Cellular trafficking through the endosomal–lysosomal system is essential for the transport of cargo proteins, receptors and lipids from the plasma membrane inside the cells and across membranous organelles. By acting as sorting stations, vesicle compartments direct the fate of their content for degradation, recycling to the membrane or transport to the trans-Golgi network. To effectively communicate with their neighbors, cells need to regulate their compartmentation and guide their signaling machineries to cortical membranes underlying these contact sites. Endosomal trafficking is indispensable for the polarized distribution of fate determinants, adaptors and junctional proteins. Conversely, endocytic machineries cooperate with polarity and scaffolding components to internalize receptors and target them to discrete membrane domains. Depending on the cell and tissue context, receptor endocytosis can terminate signaling responses but can also activate them within endosomes that act as signaling platforms. Therefore, cell homeostasis and responses to environmental cues rely on the dynamic cooperation of endosomal–lysosomal machineries with polarity and signaling cues. This review aims to address advances and emerging concepts on the cooperative regulation of endocytosis, polarity and signaling, primarily in Drosophila melanogaster and discuss some of the open questions across the different cell and tissue types that have not yet been fully explored.
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9
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Wernet N, Wernet V, Fischer R. The small-secreted cysteine-rich protein CyrA is a virulence factor participating in the attack of Caenorhabditis elegans by Duddingtonia flagrans. PLoS Pathog 2021; 17:e1010028. [PMID: 34735554 PMCID: PMC8568293 DOI: 10.1371/journal.ppat.1010028] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 10/11/2021] [Indexed: 01/14/2023] Open
Abstract
Nematode-trapping fungi (NTF) are a diverse and intriguing group of fungi that live saprotrophically but can switch to a predatory lifestyle when starving and in the presence of nematodes. NTF like Arthrobotrys oligospora or Duddingtonia flagrans produce adhesive trapping networks to catch and immobilize nematodes. After penetration of the cuticle, hyphae grow and develop inside the worm and secrete large amounts of hydrolytic enzymes for digestion. In many microbial pathogenic interactions small-secreted proteins (SSPs) are used to manipulate the host. The genome of D. flagrans encodes more than 100 of such putative SSPs one of which is the cysteine-rich protein CyrA. We have chosen this gene for further analysis because it is only found in NTF and appeared to be upregulated during the interaction. We show that the cyrA gene was transcriptionally induced in trap cells, and the protein accumulated at the inner rim of the hyphal ring before Caenorhabditis elegans capture. After worm penetration, the protein appeared at the fungal infection bulb, where it is likely to be secreted with the help of the exocyst complex. A cyrA-deletion strain was less virulent, and the time from worm capture to paralysis was extended. Heterologous expression of CyrA in C. elegans reduced its lifespan. CyrA accumulated in C. elegans in coelomocytes where the protein possibly is inactivated. This is the first example that SSPs may be important in predatory microbial interactions.
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Affiliation(s)
- Nicole Wernet
- Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Dept. of Microbiology, Karlsruhe, Germany
| | - Valentin Wernet
- Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Dept. of Microbiology, Karlsruhe, Germany
| | - Reinhard Fischer
- Karlsruhe Institute of Technology (KIT)—South Campus, Institute for Applied Biosciences, Dept. of Microbiology, Karlsruhe, Germany
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10
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Chan EHY, Zhou Y, Aerne BL, Holder MV, Weston A, Barry DJ, Collinson L, Tapon N. RASSF8-mediated transport of Echinoid via the exocyst promotes Drosophila wing elongation and epithelial ordering. Development 2021; 148:dev199731. [PMID: 34532737 PMCID: PMC8572004 DOI: 10.1242/dev.199731] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 09/13/2021] [Indexed: 01/14/2023]
Abstract
Cell-cell junctions are dynamic structures that maintain cell cohesion and shape in epithelial tissues. During development, junctions undergo extensive rearrangements to drive the epithelial remodelling required for morphogenesis. This is particularly evident during axis elongation, where neighbour exchanges, cell-cell rearrangements and oriented cell divisions lead to large-scale alterations in tissue shape. Polarised vesicle trafficking of junctional components by the exocyst complex has been proposed to promote junctional rearrangements during epithelial remodelling, but the receptors that allow exocyst docking to the target membranes remain poorly understood. Here, we show that the adherens junction component Ras Association domain family 8 (RASSF8) is required for the epithelial re-ordering that occurs during Drosophila pupal wing proximo-distal elongation. We identify the exocyst component Sec15 as a RASSF8 interactor. Loss of RASSF8 elicits cytoplasmic accumulation of Sec15 and Rab11-containing vesicles. These vesicles also contain the nectin-like homophilic adhesion molecule Echinoid, the depletion of which phenocopies the wing elongation and epithelial packing defects observed in RASSF8 mutants. Thus, our results suggest that RASSF8 promotes exocyst-dependent docking of Echinoid-containing vesicles during morphogenesis.
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Affiliation(s)
- Eunice H. Y. Chan
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Yanxiang Zhou
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Birgit L. Aerne
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Maxine V. Holder
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Anne Weston
- Electron Microscopy Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - David J. Barry
- Advanced Light Microscopy Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Lucy Collinson
- Electron Microscopy Science Technology Platform, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Nicolas Tapon
- Apoptosis and Proliferation Control Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
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11
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Thompson BJ. Par-3 family proteins in cell polarity & adhesion. FEBS J 2021; 289:596-613. [PMID: 33565714 PMCID: PMC9290619 DOI: 10.1111/febs.15754] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 01/19/2021] [Accepted: 02/08/2021] [Indexed: 12/27/2022]
Abstract
The Par‐3/Baz family of polarity determinants is highly conserved across metazoans and includes C. elegans PAR‐3, Drosophila Bazooka (Baz), human Par‐3 (PARD3), and human Par‐3‐like (PARD3B). The C. elegans PAR‐3 protein localises to the anterior pole of asymmetrically dividing zygotes with cell division cycle 42 (CDC42), atypical protein kinase C (aPKC), and PAR‐6. The same C. elegans ‘PAR complex’ can also localise in an apical ring in epithelial cells. Drosophila Baz localises to the apical pole of asymmetrically dividing neuroblasts with Cdc42‐aPKC‐Par6, while in epithelial cells localises both in an apical ring with Cdc42‐aPKC‐Par6 and with E‐cadherin at adherens junctions. These apical and junctional localisations have become separated in human PARD3, which is strictly apical in many epithelia, and human PARD3B, which is strictly junctional in many epithelia. We discuss the molecular basis for this fundamental difference in localisation, as well as the possible functions of Par‐3/Baz family proteins as oligomeric clustering agents at the apical domain or at adherens junctions in epithelial stem cells. The evolution of Par‐3 family proteins into distinct apical PARD3 and junctional PARD3B orthologs coincides with the emergence of stratified squamous epithelia in vertebrates, where PARD3B, but not PARD3, is strongly expressed in basal layer stem cells – which lack a typical apical domain. We speculate that PARD3B may contribute to clustering of E‐cadherin, signalling from adherens junctions via Src family kinases or mitotic spindle orientation by adherens junctions in response to mechanical forces.
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Affiliation(s)
- Barry J Thompson
- ACRF Department of Cancer Biology & Therapeutics, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
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12
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Aguilar-Aragon M, Fletcher G, Thompson BJ. The cytoskeletal motor proteins Dynein and MyoV direct apical transport of Crumbs. Dev Biol 2020; 459:126-137. [PMID: 31881198 PMCID: PMC7090908 DOI: 10.1016/j.ydbio.2019.12.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 12/17/2019] [Accepted: 12/17/2019] [Indexed: 12/12/2022]
Abstract
Crumbs (Crb in Drosophila; CRB1-3 in mammals) is a transmembrane determinant of epithelial cell polarity and a regulator of Hippo signalling. Crb is normally localized to apical cell-cell contacts, just above adherens junctions, but how apical trafficking of Crb is regulated in epithelial cells remains unclear. We use the Drosophila follicular epithelium to demonstrate that polarized trafficking of Crb is mediated by transport along microtubules by the motor protein Dynein and along actin filaments by the motor protein Myosin-V (MyoV). Blocking transport of Crb-containing vesicles by Dynein or MyoV leads to accumulation of Crb within Rab11 endosomes, rather than apical delivery. The final steps of Crb delivery and stabilisation at the plasma membrane requires the exocyst complex and three apical FERM domain proteins - Merlin, Moesin and Expanded - whose simultaneous loss disrupts apical localization of Crb. Accordingly, a knock-in deletion of the Crb FERM-binding motif (FBM) also impairs apical localization. Finally, overexpression of Crb challenges this system, creating a sensitized background to identify components involved in cytoskeletal polarization, apical membrane trafficking and stabilisation of Crb at the apical domain.
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Affiliation(s)
- M Aguilar-Aragon
- The Francis Crick Institute, 1 Midland Rd, NW1 1AT, London, United Kingdom
| | - G Fletcher
- The Francis Crick Institute, 1 Midland Rd, NW1 1AT, London, United Kingdom
| | - B J Thompson
- The Francis Crick Institute, 1 Midland Rd, NW1 1AT, London, United Kingdom; The John Curtin School of Medical Research, The Australian National University, 131 Garran Rd, Acton, ACT 2601, Canberra, Australia.
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13
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Bonello TT, Choi W, Peifer M. Scribble and Discs-large direct initial assembly and positioning of adherens junctions during the establishment of apical-basal polarity. Development 2019; 146:dev.180976. [PMID: 31628110 DOI: 10.1242/dev.180976] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 10/14/2019] [Indexed: 01/05/2023]
Abstract
Apical-basal polarity is a fundamental property of animal tissues. Drosophila embryos provide an outstanding model for defining mechanisms that initiate and maintain polarity. Polarity is initiated during cellularization, when cell-cell adherens junctions are positioned at the future boundary of apical and basolateral domains. Polarity maintenance then involves complementary and antagonistic interplay between apical and basal polarity complexes. The Scribble/Dlg module is well-known for promoting basolateral identity during polarity maintenance. Here, we report a surprising role for Scribble/Dlg in polarity initiation, placing it near the top of the network-positioning adherens junctions. Scribble and Dlg are enriched in nascent adherens junctions, are essential for adherens junction positioning and supermolecular assembly, and also play a role in basal junction assembly. We test the hypotheses for the underlying mechanisms, exploring potential effects on protein trafficking, cytoskeletal polarity or Par-1 localization/function. Our data suggest that the Scribble/Dlg module plays multiple roles in polarity initiation. Different domains of Scribble contribute to these distinct roles. Together, these data reveal novel roles for Scribble/Dlg as master scaffolds regulating assembly of distinct junctional complexes at different times and places.
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Affiliation(s)
- Teresa T Bonello
- Department of Biology, University of North Carolina at Chapel Hill, CB#3280, Chapel Hill, NC 27599-3280, USA
| | - Wangsun Choi
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Mark Peifer
- Department of Biology, University of North Carolina at Chapel Hill, CB#3280, Chapel Hill, NC 27599-3280, USA .,Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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14
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Bajur AT, Iyer KV, Knust E. Cytocortex-dependent dynamics of Drosophila Crumbs controls junctional stability and tension during germ band retraction. J Cell Sci 2019; 132:jcs.228338. [PMID: 31300472 DOI: 10.1242/jcs.228338] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 07/05/2019] [Indexed: 12/21/2022] Open
Abstract
During morphogenesis, epithelia undergo dynamic rearrangements, which requires continuous remodelling of junctions and cell shape, but at the same time mechanisms preserving cell polarity and tissue integrity. Apico-basal polarity is key for the localisation of the machinery that enables cell shape changes. The evolutionarily conserved Drosophila Crumbs protein is critical for maintaining apico-basal polarity and epithelial integrity. How Crumbs is maintained in a dynamically developing embryo remains largely unknown. Here, we applied quantitative fluorescence techniques to show that, during germ band retraction, Crumbs dynamics correlates with the morphogenetic activity of the epithelium. Genetic and pharmacological perturbations revealed that the mobile pool of Crumbs is fine-tuned by the actomyosin cortex in a stage-dependent manner. Stabilisation of Crumbs at the plasma membrane depends on a proper link to the actomyosin cortex via an intact FERM-domain-binding site in its intracellular domain, loss of which leads to increased junctional tension and higher DE-cadherin (also known as Shotgun) turnover, resulting in impaired junctional rearrangements. These data define Crumbs as a mediator between polarity and junctional regulation to orchestrate epithelial remodelling in response to changes in actomyosin activity.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Anna T Bajur
- Max-Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - K Venkatesan Iyer
- Max-Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Elisabeth Knust
- Max-Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
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15
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Skouloudaki K, Papadopoulos DK, Tomancak P, Knust E. The apical protein Apnoia interacts with Crumbs to regulate tracheal growth and inflation. PLoS Genet 2019; 15:e1007852. [PMID: 30645584 PMCID: PMC6333334 DOI: 10.1371/journal.pgen.1007852] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 11/25/2018] [Indexed: 12/21/2022] Open
Abstract
Most organs of multicellular organisms are built from epithelial tubes. To exert their functions, tubes rely on apico-basal polarity, on junctions, which form a barrier to separate the inside from the outside, and on a proper lumen, required for gas or liquid transport. Here we identify apnoia (apn), a novel Drosophila gene required for tracheal tube elongation and lumen stability at larval stages. Larvae lacking Apn show abnormal tracheal inflation and twisted airway tubes, but no obvious defects in early steps of tracheal maturation. apn encodes a transmembrane protein, primarily expressed in the tracheae, which exerts its function by controlling the localization of Crumbs (Crb), an evolutionarily conserved apical determinant. Apn physically interacts with Crb to control its localization and maintenance at the apical membrane of developing airways. In apn mutant tracheal cells, Crb fails to localize apically and is trapped in retromer-positive vesicles. Consistent with the role of Crb in apical membrane growth, RNAi-mediated knockdown of Crb results in decreased apical surface growth of tracheal cells and impaired axial elongation of the dorsal trunk. We conclude that Apn is a novel regulator of tracheal tube expansion in larval tracheae, the function of which is mediated by Crb.
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Affiliation(s)
- Kassiani Skouloudaki
- Max-Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
- * E-mail: (EK); (KS)
| | | | - Pavel Tomancak
- Max-Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
| | - Elisabeth Knust
- Max-Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
- * E-mail: (EK); (KS)
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16
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Exocyst Complex Member EXOC5 Is Required for Survival of Hair Cells and Spiral Ganglion Neurons and Maintenance of Hearing. Mol Neurobiol 2018; 55:6518-6532. [PMID: 29327200 PMCID: PMC6984595 DOI: 10.1007/s12035-017-0857-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 12/20/2017] [Indexed: 10/18/2022]
Abstract
The exocyst, an octameric protein complex consisting of Exoc1 through Exoc8, was first determined to regulate exocytosis by targeting vesicles to the plasma membrane in yeast to mice. In addition to this fundamental role, the exocyst complex has been implicated in other cellular processes. In this study, we investigated the role of the exocyst in cochlear development and hearing by targeting EXOC5, a central exocyst component. Deleting Exoc5 in the otic epithelium with widely used Cre lines resulted in early lethality. Thus, we generated two different inner ear-specific Exoc5 knockout models by crossing Gfi1Cre mice with Exoc5f/f mice for hair cell-specific deletion (Gfi1Cre/+;Exoc5f/f) and by in utero delivery of rAAV-iCre into the otocyst of embryonic day 12.5 for deletion throughout the otic epithelium (rAAV2/1-iCre;Exoc5f/f). Gfi1Cre/+;Exoc5f/f mice showed relatively normal hair cell morphology until postnatal day 20, after which hair cells underwent apoptosis accompanied by disorganization of stereociliary bundles, resulting in progressive hearing loss. rAAV2/1-iCre;Exoc5f/f mice exhibited abnormal neurite morphology, followed by apoptotic degeneration of spiral ganglion neurons (SGNs) and hair cells, which led to profound and early-onset hearing loss. These results demonstrate that Exoc5 is essential for the normal development and survival of cochlear hair cells and SGNs, as well as the functional maintenance of hearing.
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17
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Xie Y, Miao H, Blankenship JT. Membrane trafficking in morphogenesis and planar polarity. Traffic 2018; 19:10.1111/tra.12580. [PMID: 29756260 PMCID: PMC6235730 DOI: 10.1111/tra.12580] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 05/01/2018] [Accepted: 05/02/2018] [Indexed: 12/31/2022]
Abstract
Our understanding of how membrane trafficking pathways function to direct morphogenetic movements and the planar polarization of developing tissues is a new and emerging field. While a central focus of developmental biology has been on how protein asymmetries and cytoskeletal force generation direct cell shaping, the role of membrane trafficking in these processes has been less clear. Here, we review recent advances in Drosophila and vertebrate systems in our understanding of how trafficking events are coordinated with planar cytoskeletal function to drive lasting changes in cell and tissue topologies. We additionally explore the function of trafficking pathways in guiding the complex interactions that initiate and maintain core PCP (planar cell polarity) asymmetries and drive the generation of systematically oriented cellular projections during development.
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Affiliation(s)
- Yi Xie
- Department of Biological Sciences, University of Denver, Denver, CO
80208, USA
| | - Hui Miao
- Department of Biological Sciences, University of Denver, Denver, CO
80208, USA
| | - J. Todd Blankenship
- Department of Biological Sciences, University of Denver, Denver, CO
80208, USA
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18
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Polgar N, Fogelgren B. Regulation of Cell Polarity by Exocyst-Mediated Trafficking. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a031401. [PMID: 28264817 DOI: 10.1101/cshperspect.a031401] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
One requirement for establishing polarity within a cell is the asymmetric trafficking of intracellular vesicles to the plasma membrane. This tightly regulated process creates spatial and temporal differences in both plasma membrane composition and the membrane-associated proteome. Asymmetric membrane trafficking is also a critical mechanism to regulate cell differentiation, signaling, and physiology. Many eukaryotic cell types use the eight-protein exocyst complex to orchestrate polarized vesicle trafficking to certain membrane locales. Members of the exocyst were originally discovered in yeast while screening for proteins required for the delivery of secretory vesicles to the budding daughter cell. The same eight exocyst genes are conserved in mammals, in which the specifics of exocyst-mediated trafficking are highly cell-type-dependent. Some exocyst members bind to certain Rab GTPases on intracellular vesicles, whereas others localize to the plasma membrane at the site of exocytosis. Assembly of the exocyst holocomplex is responsible for tethering these vesicles to the plasma membrane before their soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE)-mediated exocytosis. In this review, we will focus on the role and regulation of the exocyst complex in targeted vesicular trafficking as related to the establishment and maintenance of cellular polarity. We will contrast exocyst function in apicobasal epithelial polarity versus front-back mesenchymal polarity, and the dynamic regulation of exocyst-mediated trafficking during cell phenotype transitions.
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Affiliation(s)
- Noemi Polgar
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii 96813
| | - Ben Fogelgren
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hawaii 96813
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19
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Das S, Knust E. A dual role of the extracellular domain of Drosophila Crumbs for morphogenesis of the embryonic neuroectoderm. Biol Open 2018; 7:7/1/bio031435. [PMID: 29374056 PMCID: PMC5829512 DOI: 10.1242/bio.031435] [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] [Indexed: 01/03/2023] Open
Abstract
Epithelia are highly polarised tissues and several highly conserved polarity protein complexes serve to establish and maintain polarity. The transmembrane protein Crumbs (Crb), the central component of the Crb protein complex, is required, among others, for the maintenance of polarity in most epithelia in the Drosophila embryo. However, different epithelia exhibit different phenotypic severity upon loss of crb. Using a transgenomic approach allowed us to more accurately define the role of crb in different epithelia. In particular, we provide evidence that the loss of epithelial tissue integrity in the ventral epidermis of crb mutant embryos is due to impaired actomyosin activity and an excess number of neuroblasts. We demonstrate that the intracellular domain of Crb could only partially rescue this phenotype, while it is able to completely restore tissue integrity in other epithelia. Based on these results we suggest a dual role of the extracellular domain of Crb in the ventral neuroectoderm. First, it is required for apical enrichment of the Crb protein, which in turn regulates actomyosin activity and thereby ensures tissue integrity; and second, the extracellular domain of Crb stabilises the Notch receptor and thereby ensures proper Notch signalling and specification of the correct number of neuroblasts. Summary: Using a transgenomic approach we determine specific roles of the intra- and extracellular domain of the Crumbs protein for the maintenance of apico-basal epithelial polarity and epithelial morphogenesis in Drosophila embryos.
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Affiliation(s)
- Shradha Das
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Elisabeth Knust
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
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20
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Abstract
Polarized exocytosis is generally considered as the multistep vesicular trafficking process in which membrane-bounded carriers are transported from the Golgi or endosomal compartments to specific sites of the plasma membrane. Polarized exocytosis in cells is achieved through the coordinated actions of membrane trafficking machinery and cytoskeleton orchestrated by signaling molecules such as the Rho family of small GTPases. Elucidating the molecular mechanisms of polarized exocytosis is essential to our understanding of a wide range of pathophysiological processes from neuronal development to tumor invasion.
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Affiliation(s)
- Jingwen Zeng
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6018
| | - Shanshan Feng
- Key Laboratory for Regenerative Medicine of Ministry of Education and Department of Developmental & Regenerative Biology, Jinan University, Guangzhou 510632, P.R. China
| | - Bin Wu
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6018
| | - Wei Guo
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6018
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21
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Olivares-Castiñeira I, Llimargas M. EGFR controls Drosophila tracheal tube elongation by intracellular trafficking regulation. PLoS Genet 2017; 13:e1006882. [PMID: 28678789 PMCID: PMC5517075 DOI: 10.1371/journal.pgen.1006882] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 07/19/2017] [Accepted: 06/21/2017] [Indexed: 12/12/2022] Open
Abstract
Development is governed by a few conserved signalling pathways. Amongst them, the EGFR pathway is used reiteratively for organ and tissue formation, and when dysregulated can lead to cancer and metastasis. Given its relevance, identifying its downstream molecular machinery and understanding how it instructs cellular changes is crucial. Here we approach this issue in the respiratory system of Drosophila. We identify a new role for EGFR restricting the elongation of the tracheal Dorsal Trunk. We find that EGFR regulates the apical determinant Crb and the extracellular matrix regulator Serp, two factors previously known to control tube length. EGFR regulates the organisation of endosomes in which Crb and Serp proteins are loaded. Our results are consistent with a role of EGFR in regulating Retromer/WASH recycling routes. Furthermore, we provide new insights into Crb trafficking and recycling during organ formation. Our work connects cell signalling, trafficking mechanisms and morphogenesis and suggests that the regulation of cargo trafficking can be a general outcome of EGFR activation. The control of organ size and shape is a critical aspect of morphogenesis, as miss-regulation can lead to pathologies and malformations. The tracheal system of Drosophila is a good model to investigate this issue as tube size is strictly regulated. In addition, tracheal system development represents also an excellent system to study the molecular mechanisms employed by signalling pathways to instruct cells to form tubular structures. Here we describe that EGFR, which triggers one of the principal conserved pathways acting reiteratively during development and homeostasis, is required to restrict tube elongation. We find that EGFR regulates the accumulation and subcellular localisation of Crumbs and Serpentine, two factors previously known to regulate tube length. We show that Crumbs and Serpentine are loaded in common endosomes, which require EGFR for proper organisation, ensuring delivery of both cargoes to their final destination. We also report that during tracheal development the apical determinant Crumbs undergoes a complex pattern of recycling, which involves internalisation and different sorting pathways. Our analysis identifies EGFR as a hub to coordinate both cell intrinsic properties, namely Crumbs-dependant apical membrane growth, and extrinsic mechanisms, Serpentine-mediated extracellular matrix modifications, which regulate tube elongation. We suggest that the regulation of the endocytic traffic of specific cargoes could be one of the molecular mechanisms downstream of the EGFR, and therefore could regulate different morphogenetic and pathological EGFR-mediated events.
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Affiliation(s)
- Ivette Olivares-Castiñeira
- Developmental Biology Department, Institut de Biologia Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Barcelona, Spain
| | - Marta Llimargas
- Developmental Biology Department, Institut de Biologia Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Barcelona, Spain
- * E-mail:
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22
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Lepore D, Spassibojko O, Pinto G, Collins RN. Cell cycle-dependent phosphorylation of Sec4p controls membrane deposition during cytokinesis. J Cell Biol 2017; 214:691-703. [PMID: 27621363 PMCID: PMC5021095 DOI: 10.1083/jcb.201602038] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 08/04/2016] [Indexed: 11/22/2022] Open
Abstract
The GTPase Sec4p is a critical regulator of polarized membrane traffic. Lepore et al. show that the polo-like kinase Cdc5p phosphorylates Sec4p, which promotes coordinated membrane deposition during cytokinesis. Intracellular trafficking is an essential and conserved eukaryotic process. Rab GTPases are a family of proteins that regulate and provide specificity for discrete membrane trafficking steps by harnessing a nucleotide-bound cycle. Global proteomic screens have revealed many Rab GTPases as phosphoproteins, but the effects of this modification are not well understood. Using the Saccharomyces cerevisiae Rab GTPase Sec4p as a model, we have found that phosphorylation negatively regulates Sec4p function by disrupting the interaction with the exocyst complex via Sec15p. We demonstrate that phosphorylation of Sec4p is a cell cycle–dependent process associated with cytokinesis. Through a genomic kinase screen, we have also identified the polo-like kinase Cdc5p as a positive regulator of Sec4p phosphorylation. Sec4p spatially and temporally localizes with Cdc5p exclusively when Sec4p phosphorylation levels peak during the cell cycle, indicating Sec4p is a direct Cdc5p substrate. Our data suggest the physiological relevance of Sec4p phosphorylation is to facilitate the coordination of membrane-trafficking events during cytokinesis.
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Affiliation(s)
- Dante Lepore
- Field of Biochemistry, Molecular and Cellular Biology, Cornell University, Ithaca, NY 14853 Department of Molecular Medicine, Cornell University, Ithaca, NY 14853
| | - Olya Spassibojko
- Cornell Undergraduate Biology, Cornell University, Ithaca, NY 14853
| | - Gabrielle Pinto
- Cornell Undergraduate Biology, Cornell University, Ithaca, NY 14853
| | - Ruth N Collins
- Department of Molecular Medicine, Cornell University, Ithaca, NY 14853
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23
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Brüser L, Bogdan S. Adherens Junctions on the Move-Membrane Trafficking of E-Cadherin. Cold Spring Harb Perspect Biol 2017; 9:cshperspect.a029140. [PMID: 28096264 DOI: 10.1101/cshperspect.a029140] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cadherin-based adherens junctions are conserved structures that mediate epithelial cell-cell adhesion in invertebrates and vertebrates. Despite their pivotal function in epithelial integrity, adherens junctions show a remarkable plasticity that is a prerequisite for tissue architecture and morphogenesis. Epithelial cadherin (E-cadherin) is continuously turned over and undergoes cycles of endocytosis, sorting and recycling back to the plasma membrane. Mammalian cell culture and genetically tractable model systems such as Drosophila have revealed conserved, but also distinct, mechanisms in the regulation of E-cadherin membrane trafficking. Here, we discuss our current knowledge about molecules and mechanisms controlling endocytosis, sorting and recycling of E-cadherin during junctional remodeling.
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Affiliation(s)
- Lena Brüser
- Institut für Neurobiologie, Universität Münster, Badestraße 9, 48149 Münster, Germany
| | - Sven Bogdan
- Institut für Neurobiologie, Universität Münster, Badestraße 9, 48149 Münster, Germany.,Institut für Physiologie und Pathophysiologie, Abteilung Molekulare Zellphysiologie, Phillips-Universität Marburg, Emil-Mannkopff-Straße 2, 35037 Marburg, Germany
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24
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Lee AJ, Polgar N, Napoli JA, Lui VH, Tamashiro KK, Fujimoto BA, Thompson KS, Fogelgren B. Fibroproliferative response to urothelial failure obliterates the ureter lumen in a mouse model of prenatal congenital obstructive nephropathy. Sci Rep 2016; 6:31137. [PMID: 27511831 PMCID: PMC4980620 DOI: 10.1038/srep31137] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 07/12/2016] [Indexed: 01/02/2023] Open
Abstract
Congenital obstructive nephropathy (CON) is the most prevalent cause of pediatric chronic kidney disease and end-stage renal disease. The ureteropelvic junction (UPJ) region, where the renal pelvis transitions to the ureter, is the most commonly obstructed site in CON. The underlying causes of congenital UPJ obstructions remain poorly understood, especially when they occur in utero, in part due to the lack of genetic animal models. We previously showed that conditional inactivation of Sec10, a central subunit of the exocyst complex, in the epithelial cells of the ureter and renal collecting system resulted in late gestational bilateral UPJ obstructions with neonatal anuria and death. In this study, we show that without Sec10, the urothelial progenitor cells that line the ureter fail to differentiate into superficial cells, which are responsible for producing uroplakin plaques on the luminal surface. These Sec10-knockout urothelial cells undergo cell death by E17.5 and the urothelial barrier becomes leaky to luminal fluid. Also at E17.5, we measured increased expression of TGFβ1 and genes associated with myofibroblast activation, with evidence of stromal remodeling. Our findings support the model that a defective urothelial barrier allows urine to induce a fibrotic wound healing mechanism, which may contribute to human prenatal UPJ obstructions.
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Affiliation(s)
- Amanda J Lee
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, HI 96813, USA
| | - Noemi Polgar
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, HI 96813, USA
| | - Josephine A Napoli
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, HI 96813, USA
| | - Vanessa H Lui
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, HI 96813, USA
| | - Kadee-Kalia Tamashiro
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, HI 96813, USA
| | - Brent A Fujimoto
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, HI 96813, USA
| | - Karen S Thompson
- Department of Pathology, John A. Burns School of Medicine, University of Hawaii at Manoa, HI 96813, USA
| | - Ben Fogelgren
- Department of Anatomy, Biochemistry and Physiology, John A. Burns School of Medicine, University of Hawaii at Manoa, HI 96813, USA
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25
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Román-Fernández A, Bryant DM. Complex Polarity: Building Multicellular Tissues Through Apical Membrane Traffic. Traffic 2016; 17:1244-1261. [PMID: 27281121 DOI: 10.1111/tra.12417] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 06/06/2016] [Accepted: 06/06/2016] [Indexed: 12/20/2022]
Abstract
The formation of distinct subdomains of the cell surface is crucial for multicellular organism development. The most striking example of this is apical-basal polarization. What is much less appreciated is that underpinning an asymmetric cell surface is an equally dramatic intracellular endosome rearrangement. Here, we review the interplay between classical cell polarity proteins and membrane trafficking pathways, and discuss how this marriage gives rise to cell polarization. We focus on those mechanisms that regulate apical polarization, as this is providing a number of insights into how membrane traffic and polarity are regulated at the tissue level.
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Affiliation(s)
- Alvaro Román-Fernández
- Cancer Research UK Beatson Institute, Switchback Road, Glasgow, G61 1BD, UK.,Institute of Cancer Sciences, University of Glasgow, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
| | - David M Bryant
- Cancer Research UK Beatson Institute, Switchback Road, Glasgow, G61 1BD, UK.,Institute of Cancer Sciences, University of Glasgow, Garscube Estate, Switchback Road, Glasgow, G61 1BD, UK
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26
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West JJ, Harris TJC. Cadherin Trafficking for Tissue Morphogenesis: Control and Consequences. Traffic 2016; 17:1233-1243. [DOI: 10.1111/tra.12407] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Revised: 04/20/2016] [Accepted: 04/20/2016] [Indexed: 12/27/2022]
Affiliation(s)
- Junior J. West
- Department of Cell & Systems Biology; University of Toronto; Toronto Ontario Canada
| | - Tony J. C. Harris
- Department of Cell & Systems Biology; University of Toronto; Toronto Ontario Canada
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27
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Martin-Urdiroz M, Deeks MJ, Horton CG, Dawe HR, Jourdain I. The Exocyst Complex in Health and Disease. Front Cell Dev Biol 2016; 4:24. [PMID: 27148529 PMCID: PMC4828438 DOI: 10.3389/fcell.2016.00024] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 03/11/2016] [Indexed: 01/23/2023] Open
Abstract
Exocytosis involves the fusion of intracellular secretory vesicles with the plasma membrane, thereby delivering integral membrane proteins to the cell surface and releasing material into the extracellular space. Importantly, exocytosis also provides a source of lipid moieties for membrane extension. The tethering of the secretory vesicle before docking and fusion with the plasma membrane is mediated by the exocyst complex, an evolutionary conserved octameric complex of proteins. Recent findings indicate that the exocyst complex also takes part in other intra-cellular processes besides secretion. These various functions seem to converge toward defining a direction of membrane growth in a range of systems from fungi to plants and from neurons to cilia. In this review we summarize the current knowledge of exocyst function in cell polarity, signaling and cell-cell communication and discuss implications for plant and animal health and disease.
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Affiliation(s)
| | - Michael J Deeks
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Connor G Horton
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Helen R Dawe
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
| | - Isabelle Jourdain
- Biosciences, College of Life and Environmental Sciences, University of Exeter Exeter, UK
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28
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Vichas A, Laurie MT, Zallen JA. The Ski2-family helicase Obelus regulates Crumbs alternative splicing and cell polarity. J Cell Biol 2016; 211:1011-24. [PMID: 26644515 PMCID: PMC4674277 DOI: 10.1083/jcb.201504083] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The conserved Ski2-family helicase Obelus regulates alternative splicing of the Crumbs polarity protein to control epithelial polarity and junctional organization in Drosophila. Alternative splicing can have profound consequences for protein activity, but the functions of most alternative splicing regulators are not known. We show that Obelus, a conserved Ski2-family helicase, is required for cell polarity and adherens junction organization in the Drosophila melanogaster embryo. In obelus mutants, epithelial cells display an expanded apical domain, aggregation of adherens junctions at the cell membrane, and microtubule-dependent defects in centrosome positioning. Through whole-genome transcriptome analysis, we found that Obelus is required for the alternative splicing of a small number of transcripts in the early embryo, including the pre-mRNA that encodes the apical polarity protein Crumbs. In obelus mutants, inclusion of an alternative exon results in increased expression of a Crumbs isoform that contains an additional epidermal growth factor–like repeat in the extracellular domain. Overexpression of this alternative Crumbs isoform recapitulates the junctional aggregation and centrosome positioning defects of obelus mutants. These results indicate that regulation of Crumbs alternative splicing by the Obelus helicase modulates epithelial polarity during development.
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Affiliation(s)
- Athea Vichas
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065 Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Matthew T Laurie
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065 Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065
| | - Jennifer A Zallen
- Developmental Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065 Howard Hughes Medical Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065
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Woichansky I, Beretta CA, Berns N, Riechmann V. Three mechanisms control E-cadherin localization to the zonula adherens. Nat Commun 2016; 7:10834. [PMID: 26960923 PMCID: PMC4792928 DOI: 10.1038/ncomms10834] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 01/25/2016] [Indexed: 12/13/2022] Open
Abstract
E-cadherin localization to the zonula adherens is fundamental for epithelial differentiation but the mechanisms controlling localization are unclear. Using the Drosophila follicular epithelium we genetically dissect E-cadherin transport in an in vivo model. We distinguish three mechanisms mediating E-cadherin accumulation at the zonula adherens. Two membrane trafficking pathways deliver newly synthesized E-cadherin to the plasma membrane. One is Rab11 dependent and targets E-cadherin directly to the zonula adherens, while the other transports E-cadherin to the lateral membrane. Lateral E-cadherin reaches the zonula adherens by endocytosis and targeted recycling. We show that this pathway is dependent on RabX1, which provides a functional link between early and recycling endosomes. Moreover, we show that lateral E-cadherin is transported to the zonula adherens by an apically directed flow within the plasma membrane. Differential activation of these pathways could facilitate cell shape changes during morphogenesis, while their misregulation compromises cell adhesion and tissue architecture in differentiated epithelia.
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Affiliation(s)
- Innokenty Woichansky
- Department of Cell and Molecular Biology and Division of Signaling and Functional Genomics at the German Cancer Research Center (DKFZ), Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Strasse 13-17, D-68167 Mannheim, Germany
| | - Carlo Antonio Beretta
- Heidelberg University, COS and Nikon Imaging Center at the University of Heidelberg, Bioquant, D-69120 Heidelberg, Germany
- Excellenzcluster CellNetworks, University of Heidelberg, D-69120 Heidelberg, Germany
| | - Nicola Berns
- Department of Cell and Molecular Biology and Division of Signaling and Functional Genomics at the German Cancer Research Center (DKFZ), Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Strasse 13-17, D-68167 Mannheim, Germany
| | - Veit Riechmann
- Department of Cell and Molecular Biology and Division of Signaling and Functional Genomics at the German Cancer Research Center (DKFZ), Medical Faculty Mannheim, Heidelberg University, Ludolf-Krehl-Strasse 13-17, D-68167 Mannheim, Germany
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Mavor LM, Miao H, Zuo Z, Holly RM, Xie Y, Loerke D, Blankenship JT. Rab8 directs furrow ingression and membrane addition during epithelial formation in Drosophila melanogaster. Development 2016; 143:892-903. [PMID: 26839362 PMCID: PMC4813336 DOI: 10.1242/dev.128876] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 01/25/2016] [Indexed: 01/31/2023]
Abstract
One of the most fundamental changes in cell morphology is the ingression of a plasma membrane furrow. The Drosophila embryo undergoes several cycles of rapid furrow ingression during early development that culminate in the formation of an epithelial sheet. Previous studies have demonstrated the requirement for intracellular trafficking pathways in furrow ingression; however, the pathways that link compartmental behaviors with cortical furrow ingression events are unclear. Here, we show that Rab8 has striking dynamic behaviors in vivo. As furrows ingress, cytoplasmic Rab8 puncta are depleted and Rab8 accumulates at the plasma membrane in a location that coincides with known regions of directed membrane addition. We additionally use CRISPR/Cas9 technology to N-terminally tag Rab8, which is then used to address endogenous localization and function. Endogenous Rab8 displays partial coincidence with Rab11 and the Golgi, and this colocalization is enriched during the fast phase of cellularization. When Rab8 function is disrupted, furrow formation in the early embryo is completely abolished. We also demonstrate that Rab8 behaviors require the function of the exocyst complex subunit Sec5 as well as the recycling endosome protein Rab11. Active, GTP-locked Rab8 is primarily associated with dynamic membrane compartments and the plasma membrane, whereas GDP-locked Rab8 forms large cytoplasmic aggregates. These studies suggest a model in which active Rab8 populations direct furrow ingression by guiding the targeted delivery of cytoplasmic membrane stores to the cell surface through interactions with the exocyst tethering complex.
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Affiliation(s)
- Lauren M Mavor
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
| | - Hui Miao
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
| | - Zhongyuan Zuo
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
| | - Ryan M Holly
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
| | - Yi Xie
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
| | - Dinah Loerke
- Department of Physics, University of Denver, Denver, CO 80208, USA
| | - J Todd Blankenship
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
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Sollier K, Gaudé HM, Chartier FJM, Laprise P. Rac1 controls epithelial tube length through the apical secretion and polarity pathways. Biol Open 2015; 5:49-54. [PMID: 26700724 PMCID: PMC4728308 DOI: 10.1242/bio.015727] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The morphometric parameters of epithelial tubes are critical to the physiology and homeostasis of most organs. In addition, many human diseases are associated with tube-size defects. Here, we show that Rac1 limits epithelial tube elongation in the developing fly trachea by promoting Rab5-dependent endocytosis of the apical determinant Crumbs. Rac1 is also involved in a positive feedback loop with the septate junction protein Coracle. Thereby, Rac1 precludes paracellular diffusion and contributes to the septate junction-dependent secretion of the chitin-modifying enzymes Vermiform and Serpentine, which restrict epithelial tube length independently of Crumbs. Thus, Rac1 is a critical component of two important pathways controlling epithelial tube morphogenesis. Summary: Epithelial tube size regulation sustains organ physiology. Rac1 limits tube elongation in the fly trachea through restriction of apical membrane growth, and by supporting luminal secretion of chitin modifying enzymes.
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Affiliation(s)
- Kévin Sollier
- Département de Biologie Moléculaire, Biochimie Médicale et Pathologie, Université Laval, 9 McMahon, Québec, Québec G1R 3S3, Canada Centre de recherche sur le cancer, Université Laval, 9 McMahon, Québec, Québec G1R 3S3, Canada CRCHU de Québec, axe oncologie, 9 McMahon, Québec, Québec G1R 3S3,Canada
| | - Helori-Mael Gaudé
- Département de Biologie Moléculaire, Biochimie Médicale et Pathologie, Université Laval, 9 McMahon, Québec, Québec G1R 3S3, Canada Centre de recherche sur le cancer, Université Laval, 9 McMahon, Québec, Québec G1R 3S3, Canada CRCHU de Québec, axe oncologie, 9 McMahon, Québec, Québec G1R 3S3,Canada
| | - François J-M Chartier
- Département de Biologie Moléculaire, Biochimie Médicale et Pathologie, Université Laval, 9 McMahon, Québec, Québec G1R 3S3, Canada Centre de recherche sur le cancer, Université Laval, 9 McMahon, Québec, Québec G1R 3S3, Canada CRCHU de Québec, axe oncologie, 9 McMahon, Québec, Québec G1R 3S3,Canada
| | - Patrick Laprise
- Département de Biologie Moléculaire, Biochimie Médicale et Pathologie, Université Laval, 9 McMahon, Québec, Québec G1R 3S3, Canada Centre de recherche sur le cancer, Université Laval, 9 McMahon, Québec, Québec G1R 3S3, Canada CRCHU de Québec, axe oncologie, 9 McMahon, Québec, Québec G1R 3S3,Canada
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Giansanti MG, Vanderleest TE, Jewett CE, Sechi S, Frappaolo A, Fabian L, Robinett CC, Brill JA, Loerke D, Fuller MT, Blankenship JT. Exocyst-Dependent Membrane Addition Is Required for Anaphase Cell Elongation and Cytokinesis in Drosophila. PLoS Genet 2015; 11:e1005632. [PMID: 26528720 PMCID: PMC4631508 DOI: 10.1371/journal.pgen.1005632] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 10/07/2015] [Indexed: 11/18/2022] Open
Abstract
Mitotic and cytokinetic processes harness cell machinery to drive chromosomal segregation and the physical separation of dividing cells. Here, we investigate the functional requirements for exocyst complex function during cell division in vivo, and demonstrate a common mechanism that directs anaphase cell elongation and cleavage furrow progression during cell division. We show that onion rings (onr) and funnel cakes (fun) encode the Drosophila homologs of the Exo84 and Sec8 exocyst subunits, respectively. In onr and fun mutant cells, contractile ring proteins are recruited to the equatorial region of dividing spermatocytes. However, cytokinesis is disrupted early in furrow ingression, leading to cytokinesis failure. We use high temporal and spatial resolution confocal imaging with automated computational analysis to quantitatively compare wild-type versus onr and fun mutant cells. These results demonstrate that anaphase cell elongation is grossly disrupted in cells that are compromised in exocyst complex function. Additionally, we observe that the increase in cell surface area in wild type peaks a few minutes into cytokinesis, and that onr and fun mutant cells have a greatly reduced rate of surface area growth specifically during cell division. Analysis by transmission electron microscopy reveals a massive build-up of cytoplasmic astral membrane and loss of normal Golgi architecture in onr and fun spermatocytes, suggesting that exocyst complex is required for proper vesicular trafficking through these compartments. Moreover, recruitment of the small GTPase Rab11 and the PITP Giotto to the cleavage site depends on wild-type function of the exocyst subunits Exo84 and Sec8. Finally, we show that the exocyst subunit Sec5 coimmunoprecipitates with Rab11. Our results are consistent with the exocyst complex mediating an essential, coordinated increase in cell surface area that potentiates anaphase cell elongation and cleavage furrow ingression. The cell shape changes that underlie cell division are some of the most fundamental changes in cell morphology. Here, we show that a common membrane trafficking pathway is required for both the cell lengthening that occurs during anaphase, and the physical separation of a cell into two equal daughter cells. We measure and define the periods of surface area increase during cell division in Drosophila male germline cells, and demonstrate that subunits of the exocyst tethering complex are required for this process. Invagination of the cleavage furrow fails at an early stage in exocyst mutant spermatocytes, suggesting that membrane addition is part of the initial ingression mechanism. In the absence of exocyst complex function, vesicular trafficking pathways are disrupted, leading to enlarged cytoplasmic membrane stores, and disruption of Golgi architecture. In addition, a vesicular Rab protein, Rab11, biochemically associates with the exocyst complex subunit Sec5. These results suggest that remodeling of the plasma membrane and targeted increases in surface area are an active part of the fundamental mechanisms that permit eukaryotic cell division to occur.
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Affiliation(s)
- Maria Grazia Giansanti
- Istituto di Biologia e Patologia Molecolari del CNR, Dipartimento di Biologia e Biotecnologie, Università Sapienza di Roma, Roma, Italy
- * E-mail: (MGG), (JTB)
| | | | - Cayla E. Jewett
- Department of Biological Sciences, University of Denver, Denver, Colorado, United States of America
| | - Stefano Sechi
- Istituto di Biologia e Patologia Molecolari del CNR, Dipartimento di Biologia e Biotecnologie, Università Sapienza di Roma, Roma, Italy
| | - Anna Frappaolo
- Istituto di Biologia e Patologia Molecolari del CNR, Dipartimento di Biologia e Biotecnologie, Università Sapienza di Roma, Roma, Italy
| | - Lacramioara Fabian
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Carmen C. Robinett
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - Julie A. Brill
- Cell Biology Program, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Dinah Loerke
- Department of Physics, University of Denver, Denver, Colorado, United States of America
| | - Margaret T. Fuller
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, California, United States of America
| | - J. Todd Blankenship
- Department of Biological Sciences, University of Denver, Denver, Colorado, United States of America
- * E-mail: (MGG), (JTB)
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Abstract
The exocyst is an octameric protein complex that is implicated in the tethering of secretory vesicles to the plasma membrane prior to SNARE-mediated fusion. Spatial and temporal control of exocytosis through the exocyst has a crucial role in a number of physiological processes, such as morphogenesis, cell cycle progression, primary ciliogenesis, cell migration and tumor invasion. In this Cell Science at a Glance poster article, we summarize recent works on the molecular organization, function and regulation of the exocyst complex, as they provide rationales to the involvement of this complex in such a diverse array of cellular processes.
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Affiliation(s)
- Bin Wu
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Wei Guo
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
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Holly RM, Mavor LM, Zuo Z, Blankenship JT. A rapid, membrane-dependent pathway directs furrow formation through RalA in the early Drosophila embryo. Development 2015; 142:2316-28. [PMID: 26092850 DOI: 10.1242/dev.120998] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 05/13/2015] [Indexed: 01/31/2023]
Abstract
Plasma membrane furrow formation is crucial in cell division and cytokinesis. Furrow formation in early syncytial Drosophila embryos is exceptionally rapid, with furrows forming in as little as 3.75 min. Here, we use 4D imaging to identify furrow formation, stabilization, and regression periods, and identify a rapid, membrane-dependent pathway that is essential for plasma membrane furrow formation in vivo. Myosin II function is thought to provide the ingression force for cytokinetic furrows, but the role of membrane trafficking pathways in guiding furrow formation is less clear. We demonstrate that a membrane trafficking pathway centered on Ras-like protein A (RalA) is required for fast furrow ingression in the early fly embryo. RalA function is absolutely required for furrow formation and initiation. In the absence of RalA and furrow function, chromosomal segregation is aberrant and polyploid nuclei are observed. RalA localizes to syncytial furrows, and mediates the movement of exocytic vesicles to the plasma membrane. Sec5, which is an exocyst complex subunit and localizes to ingressing furrows in wild-type embryos, becomes punctate and loses its cortical association in the absence of RalA function. Rab8 also fails to traffic to the plasma membrane and accumulates aberrantly in the cytoplasm in RalA disrupted embryos. RalA localization precedes F-actin recruitment to the furrow tip, suggesting that membrane trafficking might function upstream of cytoskeletal remodeling. These studies identify a pathway, which stretches from Rab8 to RalA and the exocyst complex, that mediates rapid furrow formation in early Drosophila embryos.
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Affiliation(s)
- Ryan M Holly
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
| | - Lauren M Mavor
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
| | - Zhongyuan Zuo
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
| | - J Todd Blankenship
- Department of Biological Sciences, University of Denver, Denver, CO 80208, USA
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Kumichel A, Kapp K, Knust E. A Conserved Di-Basic Motif of Drosophila Crumbs Contributes to Efficient ER Export. Traffic 2015; 16:604-16. [PMID: 25753515 PMCID: PMC6681134 DOI: 10.1111/tra.12273] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/10/2015] [Accepted: 02/10/2015] [Indexed: 12/31/2022]
Abstract
The Drosophila type I transmembrane protein Crumbs is an apical determinant required for the maintenance of apico‐basal epithelial cell polarity. The level of Crumbs at the plasma membrane is crucial, but how it is regulated is poorly understood. In a genetic screen for regulators of Crumbs protein trafficking we identified Sar1, the core component of the coat protein complex II transport vesicles. sar1 mutant embryos show a reduced plasma membrane localization of Crumbs, a defect similar to that observed in haunted and ghost mutant embryos, which lack Sec23 and Sec24CD, respectively. By pulse‐chase assays in Drosophila Schneider cells and analysis of protein transport kinetics based on Endoglycosidase H resistance we identified an RNKR motif in Crumbs, which contributes to efficient ER export. The motif identified fits the highly conserved di‐basic RxKR motif and mediates interaction with Sar1. The RNKR motif is also required for plasma membrane delivery of transgene‐encoded Crumbs in epithelial cells of Drosophila embryos. Our data are the first to show that a di‐basic motif acts as a signal for ER exit of a type I plasma membrane protein in a metazoan organism.
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Affiliation(s)
- Alexandra Kumichel
- Max Planck Institute of Molecular Cell Biology and GeneticsPfotenhauerstr.10801307DresdenGermany
- Present address: Membrane Traffic and Cell Division, Institut Pasteur28 rue du Dr Roux75724 ParisFrance
| | - Katja Kapp
- Max Planck Institute of Molecular Cell Biology and GeneticsPfotenhauerstr.10801307DresdenGermany
| | - Elisabeth Knust
- Max Planck Institute of Molecular Cell Biology and GeneticsPfotenhauerstr.10801307DresdenGermany
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Gillard G, Shafaq-Zadah M, Nicolle O, Damaj R, Pécréaux J, Michaux G. Control of E-cadherin apical localisation and morphogenesis by a SOAP-1/AP-1/clathrin pathway in C. elegans epidermal cells. Development 2015; 142:1684-94. [PMID: 25858456 DOI: 10.1242/dev.118216] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 03/02/2015] [Indexed: 01/05/2023]
Abstract
E-cadherin (E-cad) is the main component of epithelial junctions in multicellular organisms, where it is essential for cell-cell adhesion. The localisation of E-cad is often strongly polarised in the apico-basal axis. However, the mechanisms required for its polarised distribution are still largely unknown. We performed a systematic RNAi screen in vivo to identify genes required for the strict E-cad apical localisation in C. elegans epithelial epidermal cells. We found that the loss of clathrin, its adaptor AP-1 and the AP-1 interactor SOAP-1 induced a basolateral localisation of E-cad without affecting the apico-basal diffusion barrier. We further found that SOAP-1 controls AP-1 localisation, and that AP-1 is required for clathrin recruitment. Finally, we also show that AP-1 controls E-cad apical delivery and actin organisation during embryonic elongation, the final morphogenetic step of embryogenesis. We therefore propose that a molecular pathway, containing SOAP-1, AP-1 and clathrin, controls the apical delivery of E-cad and morphogenesis.
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Affiliation(s)
- Ghislain Gillard
- CNRS, UMR6290, Institut de Génétique et Développement de Rennes, Rennes F-35043, France Université de Rennes 1, UEB, SFR Biosit, Faculté de Médecine, Rennes F-35043, France
| | - Massiullah Shafaq-Zadah
- CNRS, UMR6290, Institut de Génétique et Développement de Rennes, Rennes F-35043, France Université de Rennes 1, UEB, SFR Biosit, Faculté de Médecine, Rennes F-35043, France
| | - Ophélie Nicolle
- CNRS, UMR6290, Institut de Génétique et Développement de Rennes, Rennes F-35043, France Université de Rennes 1, UEB, SFR Biosit, Faculté de Médecine, Rennes F-35043, France
| | - Raghida Damaj
- CNRS, UMR6290, Institut de Génétique et Développement de Rennes, Rennes F-35043, France Université de Rennes 1, UEB, SFR Biosit, Faculté de Médecine, Rennes F-35043, France
| | - Jacques Pécréaux
- CNRS, UMR6290, Institut de Génétique et Développement de Rennes, Rennes F-35043, France Université de Rennes 1, UEB, SFR Biosit, Faculté de Médecine, Rennes F-35043, France
| | - Grégoire Michaux
- CNRS, UMR6290, Institut de Génétique et Développement de Rennes, Rennes F-35043, France Université de Rennes 1, UEB, SFR Biosit, Faculté de Médecine, Rennes F-35043, France
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Le Droguen PM, Claret S, Guichet A, Brodu V. Microtubule-dependent apical restriction of recycling endosomes sustains adherens junctions during morphogenesis of the Drosophila tracheal system. Development 2015; 142:363-74. [PMID: 25564624 DOI: 10.1242/dev.113472] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Epithelial remodelling is an essential mechanism for organogenesis, during which cells change shape and position while maintaining contact with each other. Adherens junctions (AJs) mediate stable intercellular cohesion but must be actively reorganised to allow morphogenesis. Vesicle trafficking and the microtubule (MT) cytoskeleton contribute to regulating AJs but their interrelationship remains elusive. We carried out a detailed analysis of the role of MTs in cell remodelling during formation of the tracheal system in the Drosophila embryo. Induction of MT depolymerisation specifically in tracheal cells shows that MTs are essential during a specific time frame of tracheal cell elongation while the branch extends. In the absence of MTs, one tracheal cell per branch overelongates, ultimately leading to branch break. Three-dimensional quantifications revealed that MTs are crucial to sustain E-Cadherin (Shotgun) and Par-3 (Bazooka) levels at AJs. Maintaining E-Cadherin/Par-3 levels at the apical domain requires de novo synthesis rather than internalisation and recycling from and to the apical plasma membrane. However, apical targeting of E-Cadherin and Par-3 requires functional recycling endosomes, suggesting an intermediate role for this compartment in targeting de novo synthesized E-Cadherin to the plasma membrane. We demonstrate that apical enrichment of recycling endosomes is dependent on the MT motor Dynein and essential for the function of this vesicular compartment. In addition, we establish that E-Cadherin dynamics and MT requirement differ in remodelling tracheal cells versus planar epithelial cells. Altogether, our results uncover an MT-Dynein-dependent apical restriction of recycling endosomes that controls adhesion by sustaining Par-3 and E-Cadherin levels at AJs during morphogenesis.
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Affiliation(s)
- Pierre-Marie Le Droguen
- Institut Jacques Monod, CNRS and University Paris Diderot, 15 Rue H. Brion, Paris 75205, Cedex 13, France
| | - Sandra Claret
- Institut Jacques Monod, CNRS and University Paris Diderot, 15 Rue H. Brion, Paris 75205, Cedex 13, France
| | - Antoine Guichet
- Institut Jacques Monod, CNRS and University Paris Diderot, 15 Rue H. Brion, Paris 75205, Cedex 13, France
| | - Véronique Brodu
- Institut Jacques Monod, CNRS and University Paris Diderot, 15 Rue H. Brion, Paris 75205, Cedex 13, France
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Corallino S, Malabarba MG, Zobel M, Di Fiore PP, Scita G. Epithelial-to-Mesenchymal Plasticity Harnesses Endocytic Circuitries. Front Oncol 2015; 5:45. [PMID: 25767773 PMCID: PMC4341543 DOI: 10.3389/fonc.2015.00045] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 02/09/2015] [Indexed: 02/01/2023] Open
Abstract
The ability of cells to alter their phenotypic and morphological characteristics, known as cellular plasticity, is critical in normal embryonic development and adult tissue repair and contributes to the pathogenesis of diseases, such as organ fibrosis and cancer. The epithelial-to-mesenchymal transition (EMT) is a type of cellular plasticity. This transition involves genetic and epigenetic changes as well as alterations in protein expression and post-translational modifications. These changes result in reduced cell-cell adhesion, enhanced cell adhesion to the extracellular matrix, and altered organization of the cytoskeleton and of cell polarity. Among these modifications, loss of cell polarity represents the nearly invariable, distinguishing feature of EMT that frequently precedes the other traits or might even occur in their absence. EMT transforms cell morphology and physiology, and hence cell identity, from one typical of cells that form a tight barrier, like epithelial and endothelial cells, to one characterized by a highly motile mesenchymal phenotype. Time-resolved proteomic and phosphoproteomic analyses of cells undergoing EMT recently identified thousands of changes in proteins involved in many cellular processes, including cell proliferation and motility, DNA repair, and - unexpectedly - membrane trafficking (1). These results have highlighted a picture of great complexity. First, the EMT transition is not an all-or-none response but rather a gradual process that develops over time. Second, EMT events are highly dynamic and frequently reversible, involving both cell-autonomous and non-autonomous mechanisms. The net results is that EMT generates populations of mixed cells, with partial or full phenotypes, possibly accounting (at least in part) for the physiological as well as pathological cellular heterogeneity of some tissues. Endocytic circuitries have emerged as complex connectivity infrastructures for numerous cellular networks required for the execution of different biological processes, with a primary role in the control of polarized functions. Thus, they may be relevant for controlling EMT or certain aspects of it. Here, by discussing a few paradigmatic cases, we will outline how endocytosis may be harnessed by the EMT process to promote dynamic changes in cellular identity, and to increase cellular flexibility and adaptation to micro-environmental cues, ultimately impacting on physiological and pathological processes, first and foremost cancer progression.
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Affiliation(s)
| | - Maria Grazia Malabarba
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM) , Milan , Italy ; Dipartimento di Scienze della Salute, Università degli Studi di Milano , Milan , Italy
| | - Martina Zobel
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM) , Milan , Italy
| | - Pier Paolo Di Fiore
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM) , Milan , Italy ; Dipartimento di Scienze della Salute, Università degli Studi di Milano , Milan , Italy ; Dipartimento di Oncologia Sperimentale, Istituto Europeo di Oncologia , Milan , Italy
| | - Giorgio Scita
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM) , Milan , Italy ; Dipartimento di Scienze della Salute, Università degli Studi di Milano , Milan , Italy
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Szul T, Burgess J, Jeon M, Zinn K, Marques G, Brill JA, Sztul E. The Garz Sec7 domain guanine nucleotide exchange factor for Arf regulates salivary gland development in Drosophila. CELLULAR LOGISTICS 2014; 1:69-76. [PMID: 21686256 DOI: 10.4161/cl.1.2.15512] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 03/11/2011] [Accepted: 03/17/2011] [Indexed: 12/22/2022]
Abstract
Surface delivery of proteins involved in cell-cell and cell-matrix interactions in cultured mammalian cells requires the GBF1 guanine nucleotide exchange factor. However, the role of GBF1 in delivery of adhesion proteins during organogenesis in intact animals has not been characterized. Here, we report the function of the fly GBF1 homolog, Gartenzwerg (Garz) in the development of the salivary gland in Drosophila melanogaster. We used the GAL4/UAS system to selectively deplete Garz from salivary gland cells. We show that depletion of Garz disrupts the secretory pathway as evidenced by the collapse of Golgi-localized Lava lamp (Lva) and the TGN-localized γ subunit of the clathrin-adaptor protein complex (AP-1). Additionally, Garz depletion inhibits trafficking of cell-cell adhesion proteins cadherin (DE-cad) and Flamingo to the cell surface. Disregulation of trafficking correlates with mistargeting of the tumor suppressor protein Discs large involved in epithelial polarity determination. Garz-depleted salivary cells are smaller and lack well-defined plasma membrane domains. Garz depletion also inhibits normal elongation and positioning of epithelial cells, resulting in a disorganized salivary gland that lacks a well defined luminal duct. Our findings suggest that Garz is essential for establishment of epithelial structures and demonstrate an absolute requirement for Garz during Drosophila development.
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Affiliation(s)
- Tomasz Szul
- Department of Cell Biology; University of Alabama at Birmingham; Birmingham, AL USA
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40
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de Vreede G, Schoenfeld JD, Windler SL, Morrison H, Lu H, Bilder D. The Scribble module regulates retromer-dependent endocytic trafficking during epithelial polarization. Development 2014; 141:2796-802. [PMID: 25005475 DOI: 10.1242/dev.105403] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Scribble (Scrib) module proteins are major regulators of cell polarity, but how they influence membrane traffic is not known. Endocytosis is also a key regulator of polarity through roles that remain unclear. Here we link Scrib to a specific arm of the endocytic trafficking system. Drosophila mutants that block AP-2-dependent endocytosis share many phenotypes with Scrib module mutants, but Scrib module mutants show intact internalization and endolysosomal transport. However, defective traffic of retromer pathway cargo is seen, and retromer components show strong genetic interactions with the Scrib module. The Scrib module is required for proper retromer localization to endosomes and promotes appropriate cargo sorting into the retromer pathway via both aPKC-dependent and -independent mechanisms. We propose that the Scrib module regulates epithelial polarity by influencing endocytic itineraries of Crumbs and other retromer-dependent cargo.
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Affiliation(s)
- Geert de Vreede
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200, USA
| | - Joshua D Schoenfeld
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200, USA
| | - Sarah L Windler
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200, USA
| | - Holly Morrison
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200, USA
| | - Han Lu
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200, USA
| | - David Bilder
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200, USA
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41
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Eaton S, Martin-Belmonte F. Cargo sorting in the endocytic pathway: a key regulator of cell polarity and tissue dynamics. Cold Spring Harb Perspect Biol 2014; 6:a016899. [PMID: 25125399 DOI: 10.1101/cshperspect.a016899] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The establishment and maintenance of polarized plasma membrane domains is essential for cellular function and proper development of organisms. Epithelial cells polarize along two fundamental axes, the apicobasal and the planar, both depending on finely regulated protein trafficking mechanisms. Newly synthesized proteins destined for either surface domain are processed along the biosynthetic pathway and segregated into distinct subsets of transport carriers emanating from the trans-Golgi network or endosomes. This exocytic trafficking has been identified as essential for proper epithelial polarization. Accumulating evidence now reveals that endocytosis and endocytic recycling play an equally important role in epithelial polarization and the appropriate localization of key polarity proteins. Here, we review recent work in metazoan systems illuminating the connections between endocytosis, postendocytic trafficking, and cell polarity, both apicobasal and planar, in the formation of differentiated epithelial cells, and how these processes regulate tissue dynamics.
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Affiliation(s)
- Suzanne Eaton
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Fernando Martin-Belmonte
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas (CSIC), Madrid 28049, Spain
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42
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Rodriguez-Boulan E, Macara IG. Organization and execution of the epithelial polarity programme. Nat Rev Mol Cell Biol 2014; 15:225-42. [PMID: 24651541 DOI: 10.1038/nrm3775] [Citation(s) in RCA: 504] [Impact Index Per Article: 50.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Epithelial cells require apical-basal plasma membrane polarity to carry out crucial vectorial transport functions and cytoplasmic polarity to generate different cell progenies for tissue morphogenesis. The establishment and maintenance of a polarized epithelial cell with apical, basolateral and ciliary surface domains is guided by an epithelial polarity programme (EPP) that is controlled by a network of protein and lipid regulators. The EPP is organized in response to extracellular cues and is executed through the establishment of an apical-basal axis, intercellular junctions, epithelial-specific cytoskeletal rearrangements and a polarized trafficking machinery. Recent studies have provided insight into the interactions of the EPP with the polarized trafficking machinery and how these regulate epithelial polarization and depolarization.
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Affiliation(s)
- Enrique Rodriguez-Boulan
- Margaret Dyson Vision Research Institute, Weill Cornell Medical College, 1300 York Avenue, LC-301 New York City, New York 10065, USA
| | - Ian G Macara
- Department of Cell & Developmental Biology, Vanderbilt University Medical Center, 465 21st Avenue South, U 3209 MRB III, Nashville Tennessee 37232, USA
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43
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Dong B, Hannezo E, Hayashi S. Balance between apical membrane growth and luminal matrix resistance determines epithelial tubule shape. Cell Rep 2014; 7:941-50. [PMID: 24794438 DOI: 10.1016/j.celrep.2014.03.066] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Revised: 03/13/2014] [Accepted: 03/26/2014] [Indexed: 10/25/2022] Open
Abstract
The morphological stability of biological tubes is crucial for the efficient circulation of fluids and gases. Failure of this stability causes irregularly shaped tubes found in multiple pathological conditions. Here, we report that Drosophila mutants of the ESCRT III component Shrub/Vps32 exhibit a strikingly elongated sinusoidal tube phenotype. This is caused by excessive apical membrane synthesis accompanied by the ectopic accumulation and overactivation of Crumbs in swollen endosomes. Furthermore, we demonstrate that the apical extracellular matrix (aECM) of the tracheal tube is a viscoelastic material coupled with the apical membrane. We present a simple mechanical model in which aECM elasticity, apical membrane growth, and their interaction are three vital parameters determining the stability of biological tubes. Our findings demonstrate a mechanical role for the extracellular matrix and suggest that the interaction of the apical membrane and an elastic aECM determines the final morphology of biological tubes independent of cell shape.
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Affiliation(s)
- Bo Dong
- Laboratory for Morphogenetic Signaling, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan.
| | - Edouard Hannezo
- Physicochimie Curie (Institut Curie/CNRS-UMR168/UPMC), Institut Curie, Centre de Recherche, 26 rue d'Ulm, 75248 Paris Cedex 05, France
| | - Shigeo Hayashi
- Laboratory for Morphogenetic Signaling, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047, Japan; Department of Biology, Kobe University Graduate School of Science, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8051, Japan.
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44
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Apical localisation of crumbs in the boundary cells of the Drosophila hindgut is independent of its canonical interaction partner stardust. PLoS One 2014; 9:e94038. [PMID: 24710316 PMCID: PMC3977972 DOI: 10.1371/journal.pone.0094038] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 03/10/2014] [Indexed: 11/19/2022] Open
Abstract
The transmembrane protein Crumbs/Crb is a key regulator of apico-basal epithelial cell polarity, both in Drosophila and in vertebrates. In most cases studied so far, the apical localisation of Drosophila Crumbs depends on the interaction of its C-terminal amino acids with the scaffolding protein Stardust. Consequently, embryos lacking either Crumbs or Stardust develop a very similar phenotype, characterised by the loss of epithelial tissue integrity and cell polarity in many epithelia. An exception is the hindgut, which is not affected by the loss of either gene. The hindgut is a single layered epithelial tube composed of two cell populations, the boundary cells and the principal cells. Here we show that Crumbs localisation in the principal cells depends on Stardust, similarly to other embryonic epithelia. In contrast, localisation of Crumbs in the boundary cells does not require Stardust and is independent of its PDZ domain- and FERM-domain binding motifs. In line with this, the considerable upregulation of Crumbs in boundary cells is not followed by a corresponding upregulation of its canonical binding partners. Our data are the first to suggest a mechanism controlling apical Crumbs localisation, which is independent of its conserved FERM- and PDZ-domain binding motifs.
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45
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Abstract
The development of multicellular organisms relies on an intricate choreography of intercellular communication events that pattern the embryo and coordinate the formation of tissues and organs. It is therefore not surprising that developmental biology, especially using genetic model organisms, has contributed significantly to the discovery and functional dissection of the associated signal-transduction cascades. At the same time, biophysical, biochemical, and cell biological approaches have provided us with insights into the underlying cell biological machinery. Here we focus on how endocytic trafficking of signaling components (e.g., ligands or receptors) controls the generation, propagation, modulation, reception, and interpretation of developmental signals. A comprehensive enumeration of the links between endocytosis and signal transduction would exceed the limits of this review. We will instead use examples from different developmental pathways to conceptually illustrate the various functions provided by endocytic processes during key steps of intercellular signaling.
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Affiliation(s)
- Christian Bökel
- Center for Regenerative Therapies Dresden and Biotechnology Center, Technische Universität Dresden, 01307 Dresden, Germany
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46
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Wan P, Wang D, Luo J, Chu D, Wang H, Zhang L, Chen J. Guidance receptor promotes the asymmetric distribution of exocyst and recycling endosome during collective cell migration. Development 2013; 140:4797-806. [DOI: 10.1242/dev.094979] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
During collective migration, guidance receptors signal downstream to result in a polarized distribution of molecules, including cytoskeletal regulators and guidance receptors themselves, in response to an extracellular gradient of chemotactic factors. However, the underlying mechanism of asymmetry generation in the context of the migration of a group of cells is not well understood. Using border cells in the Drosophila ovary as a model system for collective migration, we found that the receptor tyrosine kinase (RTK) PDGF/VEGF receptor (PVR) is required for a polarized distribution of recycling endosome and exocyst in the leading cells of the border cell cluster. Interestingly, PVR signaled through the small GTPase Rac to positively affect the levels of Rab11-labeled recycling endosomes, probably in an F-actin-dependent manner. Conversely, the exocyst complex component Sec3 was required for the asymmetric localization of RTK activity and F-actin, similar to that previously reported for the function of Rab11. Together, these results suggested a positive-feedback loop in border cells, in which RTKs such as PVR act to induce a higher level of vesicle recycling and tethering activity in the leading cells, which in turn enables RTK activity to be distributed in a more polarized fashion at the front. We also provided evidence that E-cadherin, the major adhesion molecule for border cell migration, is a specific cargo in the Rab11-labeled recycling endosomes and that Sec3 is required for the delivery of the E-cadherin-containing vesicles to the membrane.
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Affiliation(s)
- Ping Wan
- Model Animal Research Center, and MOE Key Laboratory of Model Animals for Disease Study, Nanjing University, Nanjing, China 210061
| | - Dou Wang
- Model Animal Research Center, and MOE Key Laboratory of Model Animals for Disease Study, Nanjing University, Nanjing, China 210061
| | - Jun Luo
- Model Animal Research Center, and MOE Key Laboratory of Model Animals for Disease Study, Nanjing University, Nanjing, China 210061
| | - Dandan Chu
- Model Animal Research Center, and MOE Key Laboratory of Model Animals for Disease Study, Nanjing University, Nanjing, China 210061
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, China 226001
| | - Heng Wang
- Model Animal Research Center, and MOE Key Laboratory of Model Animals for Disease Study, Nanjing University, Nanjing, China 210061
| | - Lijun Zhang
- Model Animal Research Center, and MOE Key Laboratory of Model Animals for Disease Study, Nanjing University, Nanjing, China 210061
| | - Jiong Chen
- Model Animal Research Center, and MOE Key Laboratory of Model Animals for Disease Study, Nanjing University, Nanjing, China 210061
- Zhejiang Key Laboratory for Technology and Application of Model Organisms, School of Life Sciences, Wenzhou Medical College, Wenzhou, China 325035
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47
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Drdová EJ, Synek L, Pečenková T, Hála M, Kulich I, Fowler JE, Murphy AS, Zárský V. The exocyst complex contributes to PIN auxin efflux carrier recycling and polar auxin transport in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 73:709-19. [PMID: 23163883 DOI: 10.1111/tpj.12074] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 11/07/2012] [Accepted: 11/13/2012] [Indexed: 05/20/2023]
Abstract
In land plants polar auxin transport is one of the substantial processes guiding whole plant polarity and morphogenesis. Directional auxin fluxes are mediated by PIN auxin efflux carriers, polarly localized at the plasma membrane. The polarization of exocytosis in yeast and animals is assisted by the exocyst: an octameric vesicle-tethering complex and an effector of Rab and Rho GTPases. Here we show that rootward polar auxin transport is compromised in roots of Arabidopsis thaliana loss-of-function mutants in the EXO70A1 exocyst subunit. The recycling of PIN1 and PIN2 proteins from brefeldin-A compartments is delayed after the brefeldin-A washout in exo70A1 and sec8 exocyst mutants. Relocalization of PIN1 and PIN2 proteins after prolonged brefeldin-A treatment is largely impaired in these mutants. At the same time, however, plasma membrane localization of GFP:EXO70A1, and the other exocyst subunits studied (GFP:SEC8 and YFP:SEC10), is resistant to brefeldin-A treatment. In root cells of the exo70A1 mutant, a portion of PIN2 is internalized and retained in specific, abnormally enlarged, endomembrane compartments that are distinct from VHA-a1-labelled early endosomes or the trans-Golgi network, but are RAB-A5d positive. We conclude that the exocyst is involved in PIN1 and PIN2 recycling, and thus in polar auxin transport regulation.
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Affiliation(s)
- Edita Janková Drdová
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 16502 Prague 6, Czech Republic
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48
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Abstract
Determinants of cell polarity orient the behaviour of many cell types during development. Pioneering genetic screens in yeast, worms and flies have identified key polarity determinants that are evolutionarily conserved across the animal kingdom. Recent work in these three model organisms has combined computer modelling with experimental analysis to reveal the molecular mechanisms that drive the polarisation of determinants. Two key principles have emerged: the first is the requirement for a positive-feedback loop to drive self-recruitment of determinants to the plasma membrane; the second is the requirement for mutual antagonism between determinants that localise to opposite ends of the cell.
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Affiliation(s)
- Barry J Thompson
- Cancer Research UK, London Research Institute, Lincoln's Inn Fields, London WC2A 3LY, UK.
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49
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Nelson WJ, Dickinson DJ, Weis WI. Roles of cadherins and catenins in cell-cell adhesion and epithelial cell polarity. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 116:3-23. [PMID: 23481188 DOI: 10.1016/b978-0-12-394311-8.00001-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A simple epithelium is the building block of all metazoans and a multicellular stage of a nonmetazoan. It comprises a closed monolayer of quiescent cells that surround a luminal space. Cells are held together by cell-cell adhesion complexes and surrounded by extracellular matrix. These extracellular contacts are required for the formation of a polarized organization of plasma membrane proteins that regulate the directional absorption and secretion of ions, proteins, and other solutes. While advances have been made in understanding how proteins are sorted to different plasma membrane domains, less is known about how cell-cell adhesion is regulated and linked to the development of epithelial cell polarity and regulation of homeostasis.
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Affiliation(s)
- W James Nelson
- Department of Biology, Stanford University, Stanford, California, USA
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50
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Masaki T. Polarization and myelination in myelinating glia. ISRN NEUROLOGY 2012; 2012:769412. [PMID: 23326681 PMCID: PMC3544266 DOI: 10.5402/2012/769412] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 11/13/2012] [Indexed: 01/13/2023]
Abstract
Myelinating glia, oligodendrocytes in central nervous system and Schwann cells in peripheral nervous system, form myelin sheath, a multilayered membrane system around axons enabling salutatory nerve impulse conduction and maintaining axonal integrity. Myelin sheath is a polarized structure localized in the axonal side and therefore is supposed to be formed based on the preceding polarization of myelinating glia. Thus, myelination process is closely associated with polarization of myelinating glia. However, cell polarization has been less extensively studied in myelinating glia than other cell types such as epithelial cells. The ultimate goal of this paper is to provide insights for the field of myelination research by applying the information obtained in polarity study in other cell types, especially epithelial cells, to cell polarization of myelinating glia. Thus, in this paper, the main aspects of cell polarization study in general are summarized. Then, they will be compared with polarization in oligodendrocytes. Finally, the achievements obtained in polarization study for epithelial cells, oligodendrocytes, and other types of cells will be translated into polarization/myelination process by Schwann cells. Then, based on this model, the perspectives in the study of Schwann cell polarization/myelination will be discussed.
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Affiliation(s)
- Toshihiro Masaki
- Department of Medical Science, Teikyo University of Science, 2-2-1 Senju-Sakuragi, Adachi-ku, Tokyo 120-0045, Japan
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