1
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Perez-Mockus G, Cocconi L, Alexandre C, Aerne B, Salbreux G, Vincent JP. The Drosophila ecdysone receptor promotes or suppresses proliferation according to ligand level. Dev Cell 2023; 58:2128-2139.e4. [PMID: 37769663 PMCID: PMC7615657 DOI: 10.1016/j.devcel.2023.08.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 07/20/2023] [Accepted: 08/30/2023] [Indexed: 10/03/2023]
Abstract
The steroid hormone 20-hydroxy-ecdysone (20E) promotes proliferation in Drosophila wing precursors at low titer but triggers proliferation arrest at high doses. Remarkably, wing precursors proliferate normally in the complete absence of the 20E receptor, suggesting that low-level 20E promotes proliferation by overriding the default anti-proliferative activity of the receptor. By contrast, 20E needs its receptor to arrest proliferation. Dose-response RNA sequencing (RNA-seq) analysis of ex vivo cultured wing precursors identifies genes that are quantitatively activated by 20E across the physiological range, likely comprising positive modulators of proliferation and other genes that are only activated at high doses. We suggest that some of these "high-threshold" genes dominantly suppress the activity of the pro-proliferation genes. We then show mathematically and with synthetic reporters that combinations of basic regulatory elements can recapitulate the behavior of both types of target genes. Thus, a relatively simple genetic circuit can account for the bimodal activity of this hormone.
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Affiliation(s)
| | - Luca Cocconi
- The Francis Crick Institute, London NW1 1AT, UK.
| | | | | | - Guillaume Salbreux
- The Francis Crick Institute, London NW1 1AT, UK; Department of Genetics and Evolution, University of Geneva, Quai Ernest-Ansermet 30, 1205 Geneva, Switzerland.
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2
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Alvarez-Rodrigo I, Willnow D, Vincent JP. The logistics of Wnt production and delivery. Curr Top Dev Biol 2023; 153:1-60. [PMID: 36967191 DOI: 10.1016/bs.ctdb.2023.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
Wnts are secreted proteins that control stem cell maintenance, cell fate decisions, and growth during development and adult homeostasis. Wnts carry a post-translational modification not seen in any other secreted protein: during biosynthesis, they are appended with a palmitoleoyl moiety that is required for signaling but also impairs solubility and hence diffusion in the extracellular space. In some contexts, Wnts act only in a juxtacrine manner but there are also instances of long range action. Several proteins and processes ensure that active Wnts reach the appropriate target cells. Some, like Porcupine, Wntless, and Notum are dedicated to Wnt function; we describe their activities in molecular detail. We also outline how the cell infrastructure (secretory, endocytic, and retromer pathways) contribute to the progression of Wnts from production to delivery. We then address how Wnts spread in the extracellular space and form a signaling gradient despite carrying a hydrophobic moiety. We highlight particularly the role of lipid-binding Wnt interactors and heparan sulfate proteoglycans. Finally, we briefly discuss how evolution might have led to the emergence of this unusual signaling pathway.
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3
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Zhao Y, Mahy W, Willis NJ, Woodward HL, Steadman D, Bayle ED, Atkinson BN, Sipthorp J, Vecchia L, Ruza RR, Harlos K, Jeganathan F, Constantinou S, Costa A, Kjær S, Bictash M, Salinas PC, Whiting P, Vincent JP, Fish PV, Jones EY. Structural Analysis and Development of Notum Fragment Screening Hits. ACS Chem Neurosci 2022; 13:2060-2077. [PMID: 35731924 PMCID: PMC9264368 DOI: 10.1021/acschemneuro.2c00325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The Wnt signaling suppressor Notum is a promising target for osteoporosis, Alzheimer's disease, and colorectal cancers. To develop novel Notum inhibitors, we used an X-ray crystallographic fragment screen with the Diamond-SGC Poised Library (DSPL) and identified 59 fragment hits from the analysis of 768 data sets. Fifty-eight of the hits were found bound at the enzyme catalytic pocket with potencies ranging from 0.5 to >1000 μM. Analysis of the fragments' diverse binding modes, enzymatic inhibitory activities, and chemical properties led to the selection of six hits for optimization, and five of these resulted in improved Notum inhibitory potencies. One hit, 1-phenyl-1,2,3-triazole 7, and its related cluster members, have shown promising lead-like properties. These became the focus of our fragment development activities, resulting in compound 7d with IC50 0.0067 μM. The large number of Notum fragment structures and their initial optimization provided an important basis for further Notum inhibitor development.
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Affiliation(s)
- Yuguang Zhao
- Division
of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, The Henry Wellcome Building for Genomic Medicine,
Roosevelt Drive, Oxford OX3 7BN, U.K.
| | - William Mahy
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, The Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Nicky J. Willis
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, The Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Hannah L. Woodward
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, The Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - David Steadman
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, The Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Elliott D. Bayle
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, The Cruciform Building, Gower Street, London WC1E 6BT, U.K.
- The
Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K.
| | - Benjamin N. Atkinson
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, The Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - James Sipthorp
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, The Cruciform Building, Gower Street, London WC1E 6BT, U.K.
- The
Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K.
| | - Luca Vecchia
- Division
of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, The Henry Wellcome Building for Genomic Medicine,
Roosevelt Drive, Oxford OX3 7BN, U.K.
| | - Reinis R. Ruza
- Division
of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, The Henry Wellcome Building for Genomic Medicine,
Roosevelt Drive, Oxford OX3 7BN, U.K.
| | - Karl Harlos
- Division
of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, The Henry Wellcome Building for Genomic Medicine,
Roosevelt Drive, Oxford OX3 7BN, U.K.
| | - Fiona Jeganathan
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, The Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Stefan Constantinou
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, The Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Artur Costa
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, The Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Svend Kjær
- The
Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K.
| | - Magda Bictash
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, The Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Patricia C. Salinas
- Department
of Cell and Developmental Biology, Laboratory for Molecular and Cellular
Biology, University College London, London WC1E 6BT, U.K.
| | - Paul Whiting
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, The Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Jean-Paul Vincent
- The
Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K.
| | - Paul V. Fish
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, The Cruciform Building, Gower Street, London WC1E 6BT, U.K.
- The
Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K.
| | - E. Yvonne Jones
- Division
of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, The Henry Wellcome Building for Genomic Medicine,
Roosevelt Drive, Oxford OX3 7BN, U.K.
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4
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Willis N, Mahy W, Sipthorp J, Zhao Y, Woodward HL, Atkinson BN, Bayle ED, Svensson F, Frew S, Jeganathan F, Monaghan A, Benvegnù S, Jolly S, Vecchia L, Ruza RR, Kjær S, Howell S, Snijders AP, Bictash M, Salinas PC, Vincent JP, Jones EY, Whiting P, Fish PV. Design of a Potent, Selective, and Brain-Penetrant Inhibitor of Wnt-Deactivating Enzyme Notum by Optimization of a Crystallographic Fragment Hit. J Med Chem 2022; 65:7212-7230. [PMID: 35536179 PMCID: PMC9150124 DOI: 10.1021/acs.jmedchem.2c00162] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Indexed: 12/26/2022]
Abstract
Notum is a carboxylesterase that suppresses Wnt signaling through deacylation of an essential palmitoleate group on Wnt proteins. There is a growing understanding of the role Notum plays in human diseases such as colorectal cancer and Alzheimer's disease, supporting the need to discover improved inhibitors, especially for use in models of neurodegeneration. Here, we have described the discovery and profile of 8l (ARUK3001185) as a potent, selective, and brain-penetrant inhibitor of Notum activity suitable for oral dosing in rodent models of disease. Crystallographic fragment screening of the Diamond-SGC Poised Library for binding to Notum, supported by a biochemical enzyme assay to rank inhibition activity, identified 6a and 6b as a pair of outstanding hits. Fragment development of 6 delivered 8l that restored Wnt signaling in the presence of Notum in a cell-based reporter assay. Assessment in pharmacology screens showed 8l to be selective against serine hydrolases, kinases, and drug targets.
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Affiliation(s)
- Nicky
J. Willis
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - William Mahy
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - James Sipthorp
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
- The
Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K.
| | - Yuguang Zhao
- Division
of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, The Henry Wellcome Building for Genomic Medicine,
Roosevelt Drive, Oxford OX3 7BN, U.K.
| | - Hannah L. Woodward
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Benjamin N. Atkinson
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Elliott D. Bayle
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
- The
Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K.
| | - Fredrik Svensson
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
- The
Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K.
| | - Sarah Frew
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Fiona Jeganathan
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Amy Monaghan
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Stefano Benvegnù
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Sarah Jolly
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Luca Vecchia
- Division
of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, The Henry Wellcome Building for Genomic Medicine,
Roosevelt Drive, Oxford OX3 7BN, U.K.
| | - Reinis R. Ruza
- Division
of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, The Henry Wellcome Building for Genomic Medicine,
Roosevelt Drive, Oxford OX3 7BN, U.K.
| | - Svend Kjær
- The
Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K.
| | - Steven Howell
- The
Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K.
| | | | - Magda Bictash
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Patricia C. Salinas
- Department
of Cell and Developmental Biology, Laboratory for Molecular and Cellular
Biology, University College London, London WC1E 6BT, U.K.
| | - Jean-Paul Vincent
- The
Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K.
| | - E. Yvonne Jones
- Division
of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, The Henry Wellcome Building for Genomic Medicine,
Roosevelt Drive, Oxford OX3 7BN, U.K.
| | - Paul Whiting
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Paul V. Fish
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
- The
Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K.
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5
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Hecht S, Perez-Mockus G, Schienstock D, Recasens-Alvarez C, Merino-Aceituno S, Smith M, Salbreux G, Degond P, Vincent JP. Mechanical constraints to cell-cycle progression in a pseudostratified epithelium. Curr Biol 2022; 32:2076-2083.e2. [PMID: 35338851 PMCID: PMC7615048 DOI: 10.1016/j.cub.2022.03.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 12/14/2021] [Accepted: 03/01/2022] [Indexed: 02/07/2023]
Abstract
As organs and tissues approach their normal size during development or regeneration, growth slows down, and cell proliferation progressively comes to a halt. Among the various processes suggested to contribute to growth termination,1-10 mechanical feedback, perhaps via adherens junctions, has been suggested to play a role.11-14 However, since adherens junctions are only present in a narrow plane of the subapical region, other structures are likely needed to sense mechanical stresses along the apical-basal (A-B) axis, especially in a thick pseudostratified epithelium. This could be achieved by nuclei, which have been implicated in mechanotransduction in tissue culture.15 In addition, mechanical constraints imposed by nuclear crowding and spatial confinement could affect interkinetic nuclear migration (IKNM),16 which allows G2 nuclei to reach the apical surface, where they normally undergo mitosis.17-25 To explore how mechanical constraints affect IKNM, we devised an individual-based model that treats nuclei as deformable objects constrained by the cell cortex and the presence of other nuclei. The model predicts changes in the proportion of cell-cycle phases during growth, which we validate with the cell-cycle phase reporter FUCCI (Fluorescent Ubiquitination-based Cell Cycle Indicator).26 However, this model does not preclude indefinite growth, leading us to postulate that nuclei must migrate basally to access a putative basal signal required for S phase entry. With this refinement, our updated model accounts for the observed progressive slowing down of growth and explains how pseudostratified epithelia reach a stereotypical thickness upon completion of growth.
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Affiliation(s)
- Sophie Hecht
- The Francis Crick Institute, London NW1 1AT, UK; Imperial College London, Department of Mathematics, London SW7 2AZ, UK
| | | | | | | | - Sara Merino-Aceituno
- University of Vienna, Faculty of Mathematics, Oskar-Morgenstern-Platz 1, Wien 1090, Austria; University of Sussex, Department of Mathematics, Falmer BN1 9RH, UK
| | - Matt Smith
- The Francis Crick Institute, London NW1 1AT, UK
| | | | - Pierre Degond
- Imperial College London, Department of Mathematics, London SW7 2AZ, UK.
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6
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di Pietro F, Herszterg S, Huang A, Bosveld F, Alexandre C, Sancéré L, Pelletier S, Joudat A, Kapoor V, Vincent JP, Bellaïche Y. Rapid and robust optogenetic control of gene expression in Drosophila. Dev Cell 2021; 56:3393-3404.e7. [PMID: 34879263 PMCID: PMC8693864 DOI: 10.1016/j.devcel.2021.11.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 10/13/2021] [Accepted: 11/15/2021] [Indexed: 11/28/2022]
Abstract
Deciphering gene function requires the ability to control gene expression in space and time. Binary systems such as the Gal4/UAS provide a powerful means to modulate gene expression and to induce loss or gain of function. This is best exemplified in Drosophila, where the Gal4/UAS system has been critical to discover conserved mechanisms in development, physiology, neurobiology, and metabolism, to cite a few. Here we describe a transgenic light-inducible Gal4/UAS system (ShineGal4/UAS) based on Magnet photoswitches. We show that it allows efficient, rapid, and robust activation of UAS-driven transgenes in different tissues and at various developmental stages in Drosophila. Furthermore, we illustrate how ShineGal4 enables the generation of gain and loss-of-function phenotypes at animal, organ, and cellular levels. Thanks to the large repertoire of UAS-driven transgenes, ShineGal4 enriches the Drosophila genetic toolkit by allowing in vivo control of gene expression with high temporal and spatial resolutions.
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Affiliation(s)
- Florencia di Pietro
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR 3215, Inserm U934, Genetics and Developmental Biology, 75005 Paris, France
| | | | - Anqi Huang
- Francis Crick Institute, 1 Midland Rd, London NW1 1AT, UK
| | - Floris Bosveld
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR 3215, Inserm U934, Genetics and Developmental Biology, 75005 Paris, France
| | | | - Lucas Sancéré
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR 3215, Inserm U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Stéphane Pelletier
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR 3215, Inserm U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Amina Joudat
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR 3215, Inserm U934, Genetics and Developmental Biology, 75005 Paris, France
| | - Varun Kapoor
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR 3215, Inserm U934, Genetics and Developmental Biology, 75005 Paris, France
| | | | - Yohanns Bellaïche
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR 3215, Inserm U934, Genetics and Developmental Biology, 75005 Paris, France.
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7
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Zhao Y, Schuhmacher LN, Roberts M, Kakugawa S, Bineva-Todd G, Howell S, O'Reilly N, Perret C, Snijders AP, Vincent JP, Jones EY. Notum deacylates octanoylated ghrelin. Mol Metab 2021; 49:101201. [PMID: 33647468 PMCID: PMC8010218 DOI: 10.1016/j.molmet.2021.101201] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 02/23/2021] [Accepted: 02/24/2021] [Indexed: 01/09/2023] Open
Abstract
OBJECTIVES The only proteins known to be modified by O-linked lipidation are Wnts and ghrelin, and enzymatic removal of this post-translational modification inhibits ligand activity. Indeed, the Wnt-deacylase activity of Notum is the basis of its ability to act as a feedback inhibitor of Wnt signalling. Whether Notum also deacylates ghrelin has not been determined. METHODS We used mass spectrometry to assay ghrelin deacylation by Notum and co-crystallisation to reveal enzyme-substrate interactions at the atomic level. CRISPR/Cas technology was used to tag endogenous Notum and assess its localisation in mice while liver-specific Notum knock-out mice allowed us to investigate the physiological role of Notum in modulating the level of ghrelin deacylation. RESULTS Mass spectrometry detected the removal of octanoyl from ghrelin by purified active Notum but not by an inactive mutant. The 2.2 Å resolution crystal structure of the Notum-ghrelin complex showed that the octanoyl lipid was accommodated in the hydrophobic pocket of the Notum. The knock-in allele expressing HA-tagged Notum revealed that Notum was produced in the liver and present in the bloodstream, albeit at a low level. Liver-specific inactivation of Notum in animals fed a high-fat diet led to a small but significant increase in acylated ghrelin in the circulation, while no such increase was seen in wild-type animals on the same diet. CONCLUSIONS Overall, our data demonstrate that Notum can act as a ghrelin deacylase, and that this may be physiologically relevant under high-fat diet conditions. Our study therefore adds Notum to the list of enzymes, including butyrylcholinesterase and other carboxylesterases, that modulate the acylation state of ghrelin. The contribution of multiple enzymes could help tune the activity of this important hormone to a wide range of physiological conditions.
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Affiliation(s)
- Yuguang Zhao
- Division of Structural Biology, Wellcome Centre for Human Genetics, Oxford University, Oxford, OX3 7BN, UK
| | | | | | | | | | | | | | - Christine Perret
- Université de Paris, Institut Cochin, INSERM, CNRS, F75014 Paris, France
| | | | | | - E Yvonne Jones
- Division of Structural Biology, Wellcome Centre for Human Genetics, Oxford University, Oxford, OX3 7BN, UK.
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8
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Flanagan DJ, Pentinmikko N, Luopajärvi K, Willis NJ, Gilroy K, Raven AP, Mcgarry L, Englund JI, Webb AT, Scharaw S, Nasreddin N, Hodder MC, Ridgway RA, Minnee E, Sphyris N, Gilchrist E, Najumudeen AK, Romagnolo B, Perret C, Williams AC, Clevers H, Nummela P, Lähde M, Alitalo K, Hietakangas V, Hedley A, Clark W, Nixon C, Kirschner K, Jones EY, Ristimäki A, Leedham SJ, Fish PV, Vincent JP, Katajisto P, Sansom OJ. NOTUM from Apc-mutant cells biases clonal competition to initiate cancer. Nature 2021; 594:430-435. [PMID: 34079124 PMCID: PMC7615049 DOI: 10.1038/s41586-021-03525-z] [Citation(s) in RCA: 91] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 04/07/2021] [Indexed: 02/06/2023]
Abstract
The tumour suppressor APC is the most commonly mutated gene in colorectal cancer. Loss of Apc in intestinal stem cells drives the formation of adenomas in mice via increased WNT signalling1, but reduced secretion of WNT ligands increases the ability of Apc-mutant intestinal stem cells to colonize a crypt (known as fixation)2. Here we investigated how Apc-mutant cells gain a clonal advantage over wild-type counterparts to achieve fixation. We found that Apc-mutant cells are enriched for transcripts that encode several secreted WNT antagonists, with Notum being the most highly expressed. Conditioned medium from Apc-mutant cells suppressed the growth of wild-type organoids in a NOTUM-dependent manner. Furthermore, NOTUM-secreting Apc-mutant clones actively inhibited the proliferation of surrounding wild-type crypt cells and drove their differentiation, thereby outcompeting crypt cells from the niche. Genetic or pharmacological inhibition of NOTUM abrogated the ability of Apc-mutant cells to expand and form intestinal adenomas. We identify NOTUM as a key mediator during the early stages of mutation fixation that can be targeted to restore wild-type cell competitiveness and provide preventative strategies for people at a high risk of developing colorectal cancer.
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Affiliation(s)
| | - Nalle Pentinmikko
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
- Molecular and Integrative Bioscience Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Kalle Luopajärvi
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
- Molecular and Integrative Bioscience Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Nicky J Willis
- Alzheimer's Research UK UCL Drug Discovery Institute, University College London, London, UK
| | - Kathryn Gilroy
- Cancer Research UK Beatson Institute, Glasgow, UK
- SpecifiCancer CRUK Grand Challenge Team (C7932/A29055), Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Alexander P Raven
- Cancer Research UK Beatson Institute, Glasgow, UK
- SpecifiCancer CRUK Grand Challenge Team (C7932/A29055), Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Lynn Mcgarry
- Cancer Research UK Beatson Institute, Glasgow, UK
| | - Johanna I Englund
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
- Molecular and Integrative Bioscience Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Anna T Webb
- Department of Cell and Molecular Biology (CMB), Karolinska Institutet, Stockholm, Sweden
| | - Sandra Scharaw
- Department of Cell and Molecular Biology (CMB), Karolinska Institutet, Stockholm, Sweden
| | - Nadia Nasreddin
- Intestinal Stem Cell Biology Lab, Wellcome Trust Centre Human Genetics, University of Oxford, Oxford, UK
| | - Michael C Hodder
- Cancer Research UK Beatson Institute, Glasgow, UK
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK
| | | | - Emma Minnee
- Cancer Research UK Beatson Institute, Glasgow, UK
- Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | | | - Ella Gilchrist
- Cancer Research UK Beatson Institute, Glasgow, UK
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK
| | | | | | - Christine Perret
- Université de Paris, Institut Cochin, INSERM, CNRS, Paris, France
| | - Ann C Williams
- Colorectal Tumour Biology Group, School of Cellular and Molecular Medicine, Faculty of Life Sciences, University of Bristol, Bristol, UK
| | - Hans Clevers
- SpecifiCancer CRUK Grand Challenge Team (C7932/A29055), Department of Genetics, Harvard Medical School, Boston, MA, USA
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences, Utrecht, The Netherlands
| | - Pirjo Nummela
- Department of Pathology, Applied Tumor Genomics, Research Programs Unit and HUSLAB, HUS Diagnostic Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Marianne Lähde
- Translational Cancer Medicine Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Wihuri Research Institute, University of Helsinki, Helsinki, Finland
| | - Kari Alitalo
- Translational Cancer Medicine Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Wihuri Research Institute, University of Helsinki, Helsinki, Finland
| | - Ville Hietakangas
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland
- Molecular and Integrative Bioscience Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Ann Hedley
- Cancer Research UK Beatson Institute, Glasgow, UK
| | | | - Colin Nixon
- Cancer Research UK Beatson Institute, Glasgow, UK
| | | | - E Yvonne Jones
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Ari Ristimäki
- Department of Pathology, Applied Tumor Genomics, Research Programs Unit and HUSLAB, HUS Diagnostic Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Simon J Leedham
- Intestinal Stem Cell Biology Lab, Wellcome Trust Centre Human Genetics, University of Oxford, Oxford, UK
| | - Paul V Fish
- Alzheimer's Research UK UCL Drug Discovery Institute, University College London, London, UK
- The Francis Crick Institute, London, UK
| | | | - Pekka Katajisto
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki, Finland.
- Molecular and Integrative Bioscience Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.
- Department of Cell and Molecular Biology (CMB), Karolinska Institutet, Stockholm, Sweden.
| | - Owen J Sansom
- Cancer Research UK Beatson Institute, Glasgow, UK.
- SpecifiCancer CRUK Grand Challenge Team (C7932/A29055), Department of Genetics, Harvard Medical School, Boston, MA, USA.
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK.
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9
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Abstract
This one-step method generates, for any locus, a conditional knockout allele in Drosophila. The allele carries a bright fluorescent marker for easy screening and an attP landing site for subsequent genetic manipulations. After removing the selectable marker with Cre, the attP site can be used to insert DNA fragments expressing tagged or mutant alleles to determine protein localization and function in a tissue- and stage-specific manner. Only a single round of CRISPR-Cas9-mediated editing is required. For complete details on the use and execution of this protocol, please refer to the DWnt4[cKO] example in Yu et al. (2020).
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10
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Bayle E, Svensson F, Atkinson BN, Steadman D, Willis NJ, Woodward HL, Whiting P, Vincent JP, Fish PV. Carboxylesterase Notum Is a Druggable Target to Modulate Wnt Signaling. J Med Chem 2021; 64:4289-4311. [PMID: 33783220 PMCID: PMC8172013 DOI: 10.1021/acs.jmedchem.0c01974] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Indexed: 12/12/2022]
Abstract
Regulation of the Wnt signaling pathway is critically important for a number of cellular processes in both development and adult mammalian biology. This Perspective will provide a summary of current and emerging therapeutic opportunities in modulating Wnt signaling, especially through inhibition of Notum carboxylesterase activity. Notum was recently shown to act as a negative regulator of Wnt signaling through the removal of an essential palmitoleate group. Inhibition of Notum activity may represent a new approach to treat disease where aberrant Notum activity has been identified as the underlying cause. Reliable screening technologies are available to identify inhibitors of Notum, and structural studies are accelerating the discovery of new inhibitors. A selection of these hits have been optimized to give fit-for-purpose small molecule inhibitors of Notum. Three noteworthy examples are LP-922056 (26), ABC99 (27), and ARUK3001185 (28), which are complementary chemical tools for exploring the role of Notum in Wnt signaling.
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Affiliation(s)
- Elliott
D. Bayle
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
- The
Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K.
| | - Fredrik Svensson
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
- The
Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K.
| | - Benjamin N. Atkinson
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - David Steadman
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Nicky J. Willis
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Hannah L. Woodward
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Paul Whiting
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
| | - Jean-Paul Vincent
- The
Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K.
| | - Paul V. Fish
- Alzheimer’s
Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K.
- The
Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K.
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11
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Abstract
Cells within developing tissues rely on morphogens to assess positional information. Passive diffusion is the most parsimonious transport model for long-range morphogen gradient formation but does not, on its own, readily explain scaling, robustness and planar transport. Here, we argue that diffusion is sufficient to ensure robust morphogen gradient formation in a variety of tissues if the interactions between morphogens and their extracellular binders are considered. A current challenge is to assess how the affinity for extracellular binders, as well as other biophysical and cell biological parameters, determines gradient dynamics and shape in a diffusion-based transport system. Technological advances in genome editing, tissue engineering, live imaging and in vivo biophysics are now facilitating measurement of these parameters, paving the way for mathematical modelling and a quantitative understanding of morphogen gradient formation and modulation.
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12
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Recasens-Alvarez C, Alexandre C, Kirkpatrick J, Nojima H, Huels DJ, Snijders AP, Vincent JP. Ribosomopathy-associated mutations cause proteotoxic stress that is alleviated by TOR inhibition. Nat Cell Biol 2021; 23:127-135. [PMID: 33495632 PMCID: PMC7116740 DOI: 10.1038/s41556-020-00626-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 12/16/2020] [Indexed: 02/07/2023]
Abstract
Ribosomes are multicomponent molecular machines that synthesize all of the proteins of living cells. Most of the genes that encode the protein components of ribosomes are therefore essential. A reduction in gene dosage is often viable albeit deleterious and is associated with human syndromes, which are collectively known as ribosomopathies1-3. The cell biological basis of these pathologies has remained unclear. Here, we model human ribosomopathies in Drosophila and find widespread apoptosis and cellular stress in the resulting animals. This is not caused by insufficient protein synthesis, as reasonably expected. Instead, ribosomal protein deficiency elicits proteotoxic stress, which we suggest is caused by the accumulation of misfolded proteins that overwhelm the protein degradation machinery. We find that dampening the integrated stress response4 or autophagy increases the harm inflicted by ribosomal protein deficiency, suggesting that these activities could be cytoprotective. Inhibition of TOR activity-which decreases ribosomal protein production, slows down protein synthesis and stimulates autophagy5-reduces proteotoxic stress in our ribosomopathy model. Interventions that stimulate autophagy, combined with means of boosting protein quality control, could form the basis of a therapeutic strategy for this class of diseases.
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Affiliation(s)
| | | | | | - Hisashi Nojima
- The Francis Crick Institute, London, UK
- FUJIREBIO Inc, Tokyo, Japan
| | - David J Huels
- The Francis Crick Institute, London, UK
- Center for Experimental and Molecular Medicine, Cancer Center Amsterdam, Academic Medical Center, Amsterdam, the Netherlands
- Academic Medical Center, Oncode Institute, Amsterdam, the Netherlands
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13
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Mahy W, Willis NJ, Zhao Y, Woodward HL, Svensson F, Sipthorp J, Vecchia L, Ruza RR, Hillier J, Kjær S, Frew S, Monaghan A, Bictash M, Salinas PC, Whiting P, Vincent JP, Jones EY, Fish PV. 5-Phenyl-1,3,4-oxadiazol-2(3 H)-ones Are Potent Inhibitors of Notum Carboxylesterase Activity Identified by the Optimization of a Crystallographic Fragment Screening Hit. J Med Chem 2020; 63:12942-12956. [PMID: 33124429 DOI: 10.1021/acs.jmedchem.0c01391] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Carboxylesterase Notum is a negative regulator of the Wnt signaling pathway. There is an emerging understanding of the role Notum plays in disease, supporting the need to discover new small-molecule inhibitors. A crystallographic X-ray fragment screen was performed, which identified fragment hit 1,2,3-triazole 7 as an attractive starting point for a structure-based drug design hit-to-lead program. Optimization of 7 identified oxadiazol-2-one 23dd as a preferred example with properties consistent with drug-like chemical space. Screening 23dd in a cell-based TCF/LEF reporter gene assay restored the activation of Wnt signaling in the presence of Notum. Mouse pharmacokinetic studies with oral administration of 23dd demonstrated good plasma exposure and partial blood-brain barrier penetration. Significant progress was made in developing fragment hit 7 into lead 23dd (>600-fold increase in activity), making it suitable as a new chemical tool for exploring the role of Notum-mediated regulation of Wnt signaling.
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Affiliation(s)
- William Mahy
- Alzheimer's Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K
| | - Nicky J Willis
- Alzheimer's Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K
| | - Yuguang Zhao
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Roosevelt Drive, Oxford OX3 7BN, U.K
| | - Hannah L Woodward
- Alzheimer's Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K
| | - Fredrik Svensson
- Alzheimer's Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K
- The Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K
| | - James Sipthorp
- Alzheimer's Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K
- The Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K
| | - Luca Vecchia
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Roosevelt Drive, Oxford OX3 7BN, U.K
| | - Reinis R Ruza
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Roosevelt Drive, Oxford OX3 7BN, U.K
| | - James Hillier
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Roosevelt Drive, Oxford OX3 7BN, U.K
| | - Svend Kjær
- The Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K
| | - Sarah Frew
- Alzheimer's Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K
| | - Amy Monaghan
- Alzheimer's Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K
| | - Magda Bictash
- Alzheimer's Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K
| | - Patricia C Salinas
- Department of Cell and Developmental Biology, Laboratory for Molecular and Cellular Biology, University College London, London WC1E 6BT, U.K
| | - Paul Whiting
- Alzheimer's Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K
| | - Jean-Paul Vincent
- The Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K
| | - E Yvonne Jones
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, The Henry Wellcome Building for Genomic Medicine, Roosevelt Drive, Oxford OX3 7BN, U.K
| | - Paul V Fish
- Alzheimer's Research UK UCL Drug Discovery Institute, University College London, Cruciform Building, Gower Street, London WC1E 6BT, U.K
- The Francis Crick Institute, 1 Midland Road, Kings Cross, London NW1 1AT, U.K
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14
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Stapornwongkul KS, de Gennes M, Cocconi L, Salbreux G, Vincent JP. Patterning and growth control in vivo by an engineered GFP gradient. Science 2020; 370:321-327. [PMID: 33060356 PMCID: PMC7611032 DOI: 10.1126/science.abb8205] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 08/21/2020] [Indexed: 02/06/2023]
Abstract
Morphogen gradients provide positional information during development. To uncover the minimal requirements for morphogen gradient formation, we have engineered a synthetic morphogen in Drosophila wing primordia. We show that an inert protein, green fluorescent protein (GFP), can form a detectable diffusion-based gradient in the presence of surface-associated anti-GFP nanobodies, which modulate the gradient by trapping the ligand and limiting leakage from the tissue. We next fused anti-GFP nanobodies to the receptors of Dpp, a natural morphogen, to render them responsive to extracellular GFP. In the presence of these engineered receptors, GFP could replace Dpp to organize patterning and growth in vivo. Concomitant expression of glycosylphosphatidylinositol (GPI)-anchored nonsignaling receptors further improved patterning, to near-wild-type quality. Theoretical arguments suggest that GPI anchorage could be important for these receptors to expand the gradient length scale while at the same time reducing leakage.
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Affiliation(s)
| | - Marc de Gennes
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Luca Cocconi
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
- Imperial College, Department of Mathematics, London, UK
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15
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Yu JJS, Maugarny-Calès A, Pelletier S, Alexandre C, Bellaiche Y, Vincent JP, McGough IJ. Frizzled-Dependent Planar Cell Polarity without Secreted Wnt Ligands. Dev Cell 2020; 54:583-592.e5. [PMID: 32888416 PMCID: PMC7497783 DOI: 10.1016/j.devcel.2020.08.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/07/2020] [Accepted: 08/10/2020] [Indexed: 12/26/2022]
Abstract
Planar cell polarity (PCP) organizes the orientation of cellular protrusions and migratory activity within the tissue plane. PCP establishment involves the subcellular polarization of core PCP components. It has been suggested that Wnt gradients could provide a global cue that coordinates local PCP with tissue axes. Here, we dissect the role of Wnt ligands in the orientation of hairs of Drosophila wings, an established system for the study of PCP. We found that PCP was normal in quintuple mutant wings that rely solely on the membrane-tethered Wingless for Wnt signaling, suggesting that a Wnt gradient is not required. We then used a nanobody-based approach to trap Wntless in the endoplasmic reticulum, and hence prevent all Wnt secretion, specifically during the period of PCP establishment. PCP was still established. We conclude that, even though Wnt ligands could contribute to PCP, they are not essential, and another global cue must exist for tissue-wide polarization.
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Affiliation(s)
| | - Aude Maugarny-Calès
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, 75248 Paris Cedex 05, France; Sorbonne University, CNRS UMR 3215, INSERM U934, 75005 Paris, France
| | - Stéphane Pelletier
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, 75248 Paris Cedex 05, France; Sorbonne University, CNRS UMR 3215, INSERM U934, 75005 Paris, France
| | | | - Yohanns Bellaiche
- Institut Curie, PSL Research University, CNRS UMR 3215, INSERM U934, 75248 Paris Cedex 05, France; Sorbonne University, CNRS UMR 3215, INSERM U934, 75005 Paris, France
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16
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McGough IJ, Vecchia L, Bishop B, Malinauskas T, Beckett K, Joshi D, O'Reilly N, Siebold C, Jones EY, Vincent JP. Glypicans shield the Wnt lipid moiety to enable signalling at a distance. Nature 2020; 585:85-90. [PMID: 32699409 PMCID: PMC7610841 DOI: 10.1038/s41586-020-2498-z] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 04/23/2020] [Indexed: 12/14/2022]
Abstract
A relatively small number of proteins have been suggested to act as morphogens-signalling molecules that spread within tissues to organize tissue repair and the specification of cell fate during development. Among them are Wnt proteins, which carry a palmitoleate moiety that is essential for signalling activity1-3. How a hydrophobic lipoprotein can spread in the aqueous extracellular space is unknown. Several mechanisms, such as those involving lipoprotein particles, exosomes or a specific chaperone, have been proposed to overcome this so-called Wnt solubility problem4-6. Here we provide evidence against these models and show that the Wnt lipid is shielded by the core domain of a subclass of glypicans defined by the Dally-like protein (Dlp). Structural analysis shows that, in the presence of palmitoleoylated peptides, these glypicans change conformation to create a hydrophobic space. Thus, glypicans of the Dlp family protect the lipid of Wnt proteins from the aqueous environment and serve as a reservoir from which Wnt proteins can be handed over to signalling receptors.
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Affiliation(s)
| | - Luca Vecchia
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Benjamin Bishop
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Tomas Malinauskas
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | | | | | | | - Christian Siebold
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - E Yvonne Jones
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
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17
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Chertock A, Degond P, Hecht S, Vincent JP. Incompressible limit of a continuum model of tissue growth with segregation for two cell populations. Math Biosci Eng 2019; 16:5804-5835. [PMID: 31499739 DOI: 10.3934/mbe.2019290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
This paper proposes a model for the growth of two interacting populations of cells that do not mix. The dynamics is driven by pressure and cohesion forces on the one hand and proliferation on the other hand. Contrasting with earlier works which assume that the two populations are initially segregated, our model can deal with initially mixed populations as it explicitly incorporates a repul-sion force that enforces segregation. To balance segregation instabilities potentially triggered by the repulsion force, our model also incorporates a fourth order diffusion. In this paper, we study the influ-ence of the model parameters thanks to one-dimensional simulations using a finite-volume method for a relaxation approximation of the fourth order diffusion. Then, following earlier works on the single population case, we provide formal arguments that the model approximates a free boundary Hele Shaw type model that we characterise using both analytical and numerical arguments.
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Affiliation(s)
- Alina Chertock
- Department of Mathematics, North Carolina State University, Raleigh, NC 27695, USA
| | - Pierre Degond
- Department of Mathematics, Imperial College London, London SW7 2AZ, UK
| | - Sophie Hecht
- Department of Mathematics, Imperial College London, London SW7 2AZ, UK
- Francis Crick Institute, 1 Midland Rd, London NW1 1AT, UK
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18
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Baena-Lopez LA, Arthurton L, Bischoff M, Vincent JP, Alexandre C, McGregor R. Novel initiator caspase reporters uncover previously unknown features of caspase-activating cells. Development 2018; 145:dev170811. [PMID: 30413561 PMCID: PMC6288387 DOI: 10.1242/dev.170811] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 10/31/2018] [Indexed: 12/30/2022]
Abstract
The caspase-mediated regulation of many cellular processes, including apoptosis, justifies the substantial interest in understanding all of the biological features of these enzymes. To complement functional assays, it is crucial to identify caspase-activating cells in live tissues. Our work describes novel initiator caspase reporters that, for the first time, provide direct information concerning the initial steps of the caspase activation cascade in Drosophila tissues. One of our caspase sensors capitalises on the rapid subcellular localisation change of a fluorescent marker to uncover novel cellular apoptotic events relating to the actin-mediated positioning of the nucleus before cell delamination. The other construct benefits from caspase-induced nuclear translocation of a QF transcription factor. This feature enables the genetic manipulation of caspase-activating cells and reveals the spatiotemporal patterns of initiator caspase activity. Collectively, our sensors offer experimental opportunities not available by using previous reporters and have proven useful to illuminate previously unknown aspects of caspase-dependent processes in apoptotic and non-apoptotic cellular scenarios.
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Affiliation(s)
- Luis Alberto Baena-Lopez
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxfordshire, OX1 3RE, UK
| | - Lewis Arthurton
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxfordshire, OX1 3RE, UK
| | - Marcus Bischoff
- Biomolecular Sciences Research Complex, University of St Andrews, North Haugh, St Andrews, Fife, Scotland, KY16 9ST, UK
| | | | | | - Reuben McGregor
- Faculty of Medical and Health Sciences, Molecular Medicine & Pathology, The University of Auckland, M&HS Building 502, 85 Park Road, Grafton, Auckland 1023, New Zealand
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19
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Poernbacher I, Vincent JP. Epithelial cells release adenosine to promote local TNF production in response to polarity disruption. Nat Commun 2018; 9:4675. [PMID: 30405122 PMCID: PMC6220285 DOI: 10.1038/s41467-018-07114-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 10/15/2018] [Indexed: 12/14/2022] Open
Abstract
Disruption of epithelial integrity contributes to chronic inflammatory disorders through persistent activation of stress signalling. Here we uncover a mechanism whereby disruption of apico-basal polarity promotes stress signalling. We show that depletion of Scribbled (Scrib), a baso-lateral determinant, causes epithelial cells to release adenosine through equilibrative channels into the extracellular space. Autocrine activation of the adenosine receptor leads to transcriptional upregulation of TNF, which in turn boosts the activity of JNK signalling. Thus, disruption of cell polarity feeds into a well-established stress pathway through the intermediary of an adenosine signalling branch. Although this regulatory input could help ensuring an effective response to acute polarity stress, we suggest that it becomes deleterious in situations of low-grade chronic disruption by provoking a private inflammatory-like TNF-driven response within the polarity-deficient epithelium.
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20
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Crossman SH, Streichan SJ, Vincent JP. EGFR signaling coordinates patterning with cell survival during Drosophila epidermal development. PLoS Biol 2018; 16:e3000027. [PMID: 30379844 PMCID: PMC6231689 DOI: 10.1371/journal.pbio.3000027] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 11/12/2018] [Accepted: 10/12/2018] [Indexed: 11/19/2022] Open
Abstract
Extensive apoptosis is often seen in patterning mutants, suggesting that tissues can detect and eliminate potentially harmful mis-specified cells. Here, we show that the pattern of apoptosis in the embryonic epidermis of Drosophila is not a response to fate mis-specification but can instead be explained by the limiting availability of prosurvival signaling molecules released from locations determined by patterning information. In wild-type embryos, the segmentation cascade elicits the segmental production of several epidermal growth factor receptor (EGFR) ligands, including the transforming growth factor Spitz (TGFα), and the neuregulin, Vein. This leads to an undulating pattern of signaling activity, which prevents expression of the proapoptotic gene head involution defective (hid) throughout the epidermis. In segmentation mutants, where specific peaks of EGFR ligands fail to form, gaps in signaling activity appear, leading to coincident hid up-regulation and subsequent cell death. These data provide a mechanistic understanding of how cell survival, and thus appropriate tissue size, is made contingent on correct patterning.
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Affiliation(s)
| | - Sebastian J. Streichan
- Department of Physics, University of California, Santa Barbara, California, United States of America
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21
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Abstract
Reconstitution of a Hedgehog morphogen gradient in vitro and in silico reveals the architectural features of the signal transduction pathway that ensure rapid formation of a robust signalling gradient.
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22
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Abstract
The scaffold protein APC has a well-known function in ensuring β-catenin destruction. In this issue of Developmental Cell, Saito-Diaz et al. (2018) uncover another role for APC in Wnt signaling: to prevent clathrin-dependent signalosome formation in the absence of ligand.
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Affiliation(s)
- Ian John McGough
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
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23
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Bosch PS, Ziukaite R, Alexandre C, Basler K, Vincent JP. Dpp controls growth and patterning in Drosophila wing precursors through distinct modes of action. eLife 2017; 6:22546. [PMID: 28675374 PMCID: PMC5560859 DOI: 10.7554/elife.22546] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 06/04/2017] [Indexed: 11/13/2022] Open
Abstract
Dpp, a member of the BMP family, is a morphogen that specifies positional information in Drosophila wing precursors. In this tissue, Dpp expressed along the anterior-posterior boundary forms a concentration gradient that controls the expression domains of target genes, which in turn specify the position of wing veins. Dpp also promotes growth in this tissue. The relationship between the spatio-temporal profile of Dpp signalling and growth has been the subject of debate, which has intensified recently with the suggestion that the stripe of Dpp is dispensable for growth. With two independent conditional alleles of dpp, we find that the stripe of Dpp is essential for wing growth. We then show that this requirement, but not patterning, can be fulfilled by uniform, low level, Dpp expression. Thus, the stripe of Dpp ensures that signalling remains above a pro-growth threshold, while at the same time generating a gradient that patterns cell fates. DOI:http://dx.doi.org/10.7554/eLife.22546.001 From the wings of a butterfly to the fingers of a human hand, living tissues often have complex and intricate patterns. Developmental biologists have long been fascinated by the signals – called morphogens – that guide how these kinds of pattern develop. Morphogens are substances that are produced by groups of cells and spread to the rest of the tissue to form a gradient. Depending on where they sit along this gradient, cells in the tissue activate different sets of genes, and the resulting pattern of gene activity ultimately defines the position of the different parts of the tissue. Decades worth of studies into how limbs develop in animals from mice to fruit flies have revealed common principles of morphogen gradients that regulate the development of tissue patterns. Morphogens have been shown to help regulate the growth of tissues in a number of different animals as well. However, how the morphogens regulate tissue size and what role their gradients play in this process remain topics of intense debate in the field of developmental biology. In the developing wing of a fruit fly, a morphogen called Dpp is expressed in a thin stripe located in the centre and spreads to the rest of the tissue to form a gradient. Bosch, Ziukaite, Alexandre et al. have now characterised where and when the Dpp morphogen must be produced to regulate both the final size of the fly’s wing and the number of cells the wing eventually contains. The experiments involved preventing the production of Dpp in the developing wing in specific cells and at specific stages of development. This approach confirmed that Dpp must be produced in the central stripe for the wing to grow. Matsuda and Affolter and, independently, Barrio and Milán report the same findings in two related studies. Moreover, Bosch et al. and Barrio and Milán also conclude that the gradient of Dpp throughout the wing is not required for growth. Further work will be needed to explain how the Dpp signal regulates the growth of the wing. The answer to this question will contribute to a better understanding of the role of morphogens in regulating the size of human organs and how a failure to do so might cause developmental disorders. DOI:http://dx.doi.org/10.7554/eLife.22546.002
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Affiliation(s)
- Pablo Sanchez Bosch
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
| | | | | | - Konrad Basler
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
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24
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Abstract
Decapentaplegic has long been thought to be a morphogen that controls patterning and growth in Drosophila wings, but hard evidence for the requisite long-range action has only now come from two new studies.
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Affiliation(s)
- Jean-Paul Vincent
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, London NW7 1AA, UK.
| | - Ruta Ziukaite
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, London NW7 1AA, UK
| | - Cyrille Alexandre
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, London NW7 1AA, UK
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25
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Abstract
In order to achieve coordinated growth and patterning during development, cells must communicate with one another, sending and receiving signals that regulate their activities. Such developmental signals can be soluble, bound to the extracellular matrix, or tethered to the surface of adjacent cells. Cells can also signal by releasing exosomes – extracellular vesicles containing bioactive molecules such as RNA, DNA and enzymes. Recent work has suggested that exosomes can also carry signalling proteins, including ligands of the Notch receptor and secreted proteins of the Hedgehog and WNT families. Here, we describe the various types of exosomes and their biogenesis. We then survey the experimental strategies used so far to interfere with exosome formation and critically assess the role of exosomes in developmental signalling.
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Affiliation(s)
- Ian John McGough
- Laboratory of Epithelial Interactions, The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, London NW7 1AA, UK
| | - Jean-Paul Vincent
- Laboratory of Epithelial Interactions, The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, London NW7 1AA, UK
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26
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Langton PF, Kakugawa S, Vincent JP. Making, Exporting, and Modulating Wnts. Trends Cell Biol 2016; 26:756-765. [PMID: 27325141 DOI: 10.1016/j.tcb.2016.05.011] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 05/15/2016] [Accepted: 05/20/2016] [Indexed: 10/21/2022]
Abstract
Wnt proteins activate a conserved signalling pathway that controls development and tissue homeostasis in all metazoans. The intensity of Wnt signalling must be tightly controlled to avoid diseases caused by excess or ectopic signalling. Over the years, many proteins dedicated to Wnt function have been identified, including Porcupine, which appends a palmitoleate moiety that is essential for signalling activity. This lipid inevitably affects subcellular trafficking and solubility, as well as providing a target for post-translational modulation. We review here the life history of Wnts, starting with progression through the secretory pathway, continuing with release and spread in the extracellular space, and finishing with the various proteins that dampen or inactivate Wnts in the extracellular space.
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Affiliation(s)
- Paul F Langton
- The Henry Wellcome Integrated Signalling Laboratories, School of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - Satoshi Kakugawa
- Hakuhodo Medical Inc., 6-1-20 Akasaka Minato-ku, Tokyo 107-0052, Japan
| | - Jean-Paul Vincent
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, London NW7 1AA, UK.
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27
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Yamazaki Y, Palmer L, Alexandre C, Kakugawa S, Beckett K, Gaugue I, Palmer RH, Vincent JP. Godzilla-dependent transcytosis promotes Wingless signalling in Drosophila wing imaginal discs. Nat Cell Biol 2016; 18:451-7. [PMID: 26974662 PMCID: PMC4817240 DOI: 10.1038/ncb3325] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 02/05/2016] [Indexed: 12/18/2022]
Abstract
The apical and basolateral membranes of epithelia are insulated from each other, preventing the transfer of extracellular proteins from one side to the other. Thus, a signalling protein produced apically is not expected to reach basolateral receptors. Evidence suggests that Wingless, the main Drosophila Wnt, is secreted apically in the embryonic epidermis. However, in the wing imaginal disc epithelium, Wingless is mostly seen on the basolateral membrane where it spreads from secreting to receiving cells. Here we examine the apico-basal movement of Wingless in Wingless-producing cells of wing imaginal discs. We find that it is presented first on the apical surface before making its way to the basolateral surface, where it is released and allowed to interact with signalling receptors. We show that Wingless transcytosis involves dynamin-dependent endocytosis from the apical surface. Subsequent trafficking from early apical endosomes to the basolateral surface requires Godzilla, a member of the RNF family of membrane-anchored E3 ubiquitin ligases. Without such transport, Wingless signalling is strongly reduced in this tissue.
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Affiliation(s)
- Yasuo Yamazaki
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, The Sahlgrenska Academy at the University of Gothenburg, Medicinaregatan 9A, 40539 Gothenburg, Sweden
| | - Lucy Palmer
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Cyrille Alexandre
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Satoshi Kakugawa
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Karen Beckett
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Isabelle Gaugue
- Polarity, Division and Morphogenesis Team, Institut Curie, CNRS UMR 3215, INSERM U934, 26 rue d'Ulm, 75248 Paris Cedex 05, France
| | - Ruth H Palmer
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, The Sahlgrenska Academy at the University of Gothenburg, Medicinaregatan 9A, 40539 Gothenburg, Sweden
| | - Jean-Paul Vincent
- The Francis Crick Institute, Mill Hill Laboratory, The Ridgeway, Mill Hill, London NW7 1AA, UK
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Kakugawa S, Langton PF, Zebisch M, Howell S, Chang TH, Liu Y, Feizi T, Bineva G, O’Reilly N, Snijders AP, Jones EY, Vincent JP. Notum deacylates Wnt proteins to suppress signalling activity. Nature 2015; 519:187-192. [PMID: 25731175 PMCID: PMC4376489 DOI: 10.1038/nature14259] [Citation(s) in RCA: 281] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 01/26/2015] [Indexed: 01/23/2023]
Abstract
Signalling by Wnt proteins is finely balanced to ensure normal development and tissue homeostasis while avoiding diseases such as cancer. This is achieved in part by Notum, a highly conserved secreted feedback antagonist. Notum has been thought to act as a phospholipase, shedding glypicans and associated Wnt proteins from the cell surface. However, this view fails to explain specificity, as glypicans bind many extracellular ligands. Here we provide genetic evidence in Drosophila that Notum requires glypicans to suppress Wnt signalling, but does not cleave their glycophosphatidylinositol anchor. Structural analyses reveal glycosaminoglycan binding sites on Notum, which probably help Notum to co-localize with Wnt proteins. They also identify, at the active site of human and Drosophila Notum, a large hydrophobic pocket that accommodates palmitoleate. Kinetic and mass spectrometric analyses of human proteins show that Notum is a carboxylesterase that removes an essential palmitoleate moiety from Wnt proteins and thus constitutes the first known extracellular protein deacylase.
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Affiliation(s)
- Satoshi Kakugawa
- MRC’s National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Paul F. Langton
- MRC’s National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Matthias Zebisch
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK
| | - Steve Howell
- MRC’s National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
| | - Tao-Hsin Chang
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK
| | - Yan Liu
- Glycosciences Laboratory, Imperial College London, Department of Medicine Du Cane Road, London, W12 0NN UK
| | - Ten Feizi
- Glycosciences Laboratory, Imperial College London, Department of Medicine Du Cane Road, London, W12 0NN UK
| | - Ganka Bineva
- Cancer Research UK, London Research Institute, 44 Lincoln’s Inn Fields, London WC2A 3LY, UK
| | - Nicola O’Reilly
- Cancer Research UK, London Research Institute, 44 Lincoln’s Inn Fields, London WC2A 3LY, UK
| | - Ambrosius P. Snijders
- Cancer Research UK, Clare Hall Laboratories, Blanche Lane, South Mimms, Potters Bar, Hertfordshire. EN6 3LD, UK
| | - E. Yvonne Jones
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK
| | - Jean-Paul Vincent
- MRC’s National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
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Gagliardi M, Hernandez A, McGough IJ, Vincent JP. Inhibitors of endocytosis prevent Wnt/Wingless signalling by reducing the level of basal β-catenin/Armadillo. Development 2014. [DOI: 10.1242/dev.119370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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30
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Beira JV, Springhorn A, Gunther S, Hufnagel L, Pyrowolakis G, Vincent JP. The Dpp/TGFβ-dependent corepressor Schnurri protects epithelial cells from JNK-induced apoptosis in drosophila embryos. Dev Cell 2014; 31:240-7. [PMID: 25307481 PMCID: PMC4220000 DOI: 10.1016/j.devcel.2014.08.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 06/27/2014] [Accepted: 08/11/2014] [Indexed: 12/16/2022]
Abstract
Jun N-terminal kinase (JNK) often mediates apoptosis in response to cellular stress. However, during normal development, JNK signaling controls a variety of live cell behaviors, such as during dorsal closure in Drosophila embryos. During this process, the latent proapoptotic activity of JNK becomes apparent following Dpp signaling suppression, which leads to JNK-dependent transcriptional activation of the proapoptotic gene reaper. Dpp signaling also protects cells from JNK-dependent apoptosis caused by epithelial disruption. We find that repression of reaper transcription by Dpp is mediated by Schnurri. Moreover, reporter gene analysis shows that a transcriptional regulatory module comprising AP-1 and Schnurri binding sites located upstream of reaper integrate the activities of JNK and Dpp. This arrangement allows JNK to control a migratory behavior without triggering apoptosis. Dpp plays a dual role during dorsal closure. It cooperates with JNK in stimulating cell migration and also prevents JNK from inducing apoptosis.
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Affiliation(s)
- Jorge V Beira
- Medical Research Council National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK; Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK.
| | - Alexander Springhorn
- BIOSS Centre for Biological Signalling Studies and Institute for Biology I, University of Freiburg, Schänzlestrasse 18, 79104 Freiburg, Germany; Spemann Graduate School of Biology and Medicine, Research Training Program GRK 1104, Albert Ludwigs University, 79104 Freiburg, Germany
| | - Stefan Gunther
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Lars Hufnagel
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Giorgos Pyrowolakis
- BIOSS Centre for Biological Signalling Studies and Institute for Biology I, University of Freiburg, Schänzlestrasse 18, 79104 Freiburg, Germany
| | - Jean-Paul Vincent
- Medical Research Council National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK.
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31
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Gagliardi M, Hernandez A, McGough IJ, Vincent JP. Inhibitors of endocytosis prevent Wnt/Wingless signalling by reducing the level of basal β-catenin/Armadillo. J Cell Sci 2014; 127:4918-26. [PMID: 25236598 PMCID: PMC4231306 DOI: 10.1242/jcs.155424] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
A key step in the canonical Wnt signalling pathway is the inhibition of GSK3β, which results in the accumulation of nuclear β-catenin (also known as CTNNB1), and hence regulation of target genes. Evidence suggests that endocytosis is required for signalling, yet its role and the molecular understanding remains unclear. A recent and controversial model suggests that endocytosis contributes to Wnt signalling by causing the sequestration of the ligand-receptor complex, including LRP6 and GSK3 to multivesicular bodies (MVBs), thus preventing GSK3β from accessing β-catenin. Here, we use specific inhibitors (Dynasore and Dyngo-4a) to confirm the essential role of endocytosis in Wnt/Wingless signalling in human and Drosophila cells. However, we find no evidence that, in Drosophila cells or wing imaginal discs, LRP6/Arrow traffics to MVBs or that MVBs are required for Wnt/Wingless signalling. Moreover, we show that activation of signalling through chemical blockade of GSK3β is prevented by endocytosis inhibitors, suggesting that endocytosis impacts on Wnt/Wingless signalling downstream of the ligand-receptor complex. We propose that, through an unknown mechanism, endocytosis boosts the resting pool of β-catenin upon which GSK3β normally acts.
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Affiliation(s)
- Maria Gagliardi
- MRC's National Institute for Medical Research, The Ridgeway, Mill Hill, London NW71AA, UK
| | - Ana Hernandez
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Ian J McGough
- MRC's National Institute for Medical Research, The Ridgeway, Mill Hill, London NW71AA, UK
| | - Jean-Paul Vincent
- MRC's National Institute for Medical Research, The Ridgeway, Mill Hill, London NW71AA, UK
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32
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Abstract
The main Wnt ligand of Drosophila activates a conserved canonical signalling pathway to regulate a plethora of cellular activities during development, regeneration and nervous system function. Here I first describe experimental means of measuring and modulating Wingless signalling in Drosophila cell culture. Various reporters have been devised by placing TCF-binding sites or DNA fragments from known target genes upstream of luciferase-coding sequences. Signalling can be activated in cells by addition of Wingless conditioned medium, treatment with a chemical inhibitor of Shaggy/GSK3 or transfection with a plasmid encoding activated Armadillo (Drosophila β-catenin). Measuring Wingless signalling in intact tissue is somewhat more challenging than in cell culture. Synthetic transgenic reporters have been devised but further improvements are needed to achieve sensitive responsiveness to Wingless at all times and places. As an alternative, gene traps in frizzled3 and notum/wingful, two context-independent endogenous targets, can be used as reporters. It is hoped that further modification of these loci could lead to more versatile and sensitive means of detecting signalling. Many genetic tools are available to trigger ectopic signalling or prevent endogenous signalling. These mostly rely on RNAi-producing transgenes or the generation of mutant patches by mitotic recombination. New developments in genome engineering are opening further means of manipulating the components of Wingless signalling with exquisite temporal and spatial precision.
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Affiliation(s)
- Jean-Paul Vincent
- MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW71AA, United Kingdom.
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33
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Abstract
Drosophila has helped us understand the genetic mechanisms of pattern formation. Particularly useful have been those organs in which different cell identities and polarities are displayed cell by cell in the cuticle and epidermis (Lawrence, 1992; Bejsovec and Wieschaus, 1993; Freeman, 1997). Here we use the pattern of larval denticles and muscle attachments and ask how this pattern is maintained and renewed over the larval moult cycles. During larval growth each epidermal cell increases manyfold in size but neither divides nor dies. We follow individuals from moult to moult, tracking marked cells and find that, as cells are repositioned and alter their neighbours, their identities change to compensate and the pattern is conserved. Single cells adopting a new fate may even acquire a new polarity: an identified cell that makes a forward-pointing denticle in the first larval stage may make a backward-pointing denticle in the second and third larval stages. DOI:http://dx.doi.org/10.7554/eLife.01569.001 Fly larvae grow in an unusual way. Most embryos grow by increasing the number of cells in the embryo, but fly larvae grow by increasing the size of their cells. The epidermal cells in the growing larvae secrete a hard skin or cuticle that is renewed three times as they grow. This cuticle is decorated with teeth called denticles that the larvae use to grip surfaces as they crawl on them. The denticles are arranged in six rows during all three larval stages. It has long been assumed that if a cell in the first larval stage makes the denticles belonging to a given row, then the same cell will make denticles in the same row in the second and third larval stages. Now Saavedra et al. report that this assumption is mistaken and that the epidermal cells rearrange extensively between the first and second larval stages, and that cells acquire different identities to keep the pattern constant. Saavedra et al. marked small groups of cells in the embryo and plotted the positions of these cells as the larvae progressed through the three stages of development. These measurements showed that as the larvae grow, the cells changed their positions relative to each other. This meant that, in order to keep essentially the same pattern of denticle rows, the cells had to change their identity. Some of these changes were quite dramatic. Consider, for example, the embryonic cells that make the denticles in the second of the six rows during the first larval stage. In the embryo, these cells are tendons and attach to the muscles needed for crawling. Saavedra et al. found that these cells remain attached to the same muscles throughout growth, but that they do not make denticles during the second and third larval stages. Instead, the denticles in the second row of later larval stages are made by other cells, and these new second row cells are not attached to any muscles. In another example of these changes, some cells make denticles that point away from the head during the first larval stage, and then make denticles that point towards the head during later stages. Thus, cells can change both their identity (e.g., whether they are attached to muscles or not) and their orientation (also known as the cell polarity) during the development of a larva. The work of Saavedra et al. illustrates how organisms adapt developmental mechanisms that have been stabilised for millions of years and for this reason limit the kinds of morphological changes that are possible. DOI:http://dx.doi.org/10.7554/eLife.01569.002
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Affiliation(s)
- Pedro Saavedra
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
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34
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Abstract
In vivo time-lapse imaging and functional tests bring fresh evidence that the morphogen Hedgehog is conveyed to target cells via long filopodia extensions, dubbed cytonemes. This study provides the tools and conceptual framework to understand how cytonemes form and carry morphogens.
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Affiliation(s)
- James Briscoe
- MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, NW7 1AA, UK
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35
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Abstract
Wnts are evolutionarily conserved secreted signalling proteins that, in various developmental contexts, spread from their site of synthesis to form a gradient and activate target-gene expression at a distance. However, the requirement for Wnts to spread has never been directly tested. Here we used genome engineering to replace the endogenous wingless gene, which encodes the main Drosophila Wnt, with one that expresses a membrane-tethered form of the protein. Surprisingly, the resulting flies were viable and produced normally patterned appendages of nearly the right size, albeit with a delay. We show that, in the prospective wing, prolonged wingless transcription followed by memory of earlier signalling allows persistent expression of relevant target genes. We suggest therefore that the spread of Wingless is dispensable for patterning and growth even though it probably contributes to increasing cell proliferation.
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Affiliation(s)
- Cyrille Alexandre
- 1] MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK [2]
| | - Alberto Baena-Lopez
- 1] MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK [2]
| | - Jean-Paul Vincent
- MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
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36
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Baena-Lopez LA, Alexandre C, Mitchell A, Pasakarnis L, Vincent JP. Accelerated homologous recombination and subsequent genome modification in Drosophila. Development 2013; 140:4818-25. [PMID: 24154526 PMCID: PMC3833436 DOI: 10.1242/dev.100933] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Gene targeting by ‘ends-out’ homologous recombination enables the deletion of genomic sequences and concurrent introduction of exogenous DNA with base-pair precision without sequence constraint. In Drosophila, this powerful technique has remained laborious and hence seldom implemented. We describe a targeting vector and protocols that achieve this at high frequency and with very few false positives in Drosophila, either with a two-generation crossing scheme or by direct injection in embryos. The frequency of injection-mediated gene targeting can be further increased with CRISPR-induced double-strand breaks within the region to be deleted, thus making homologous recombination almost as easy as conventional transgenesis. Our targeting vector replaces genomic sequences with a multifunctional fragment comprising an easy-to-select genetic marker, a fluorescent reporter, as well as an attP site, which acts as a landing platform for reintegration vectors. These vectors allow the insertion of a variety of transcription reporters or cDNAs to express tagged or mutant isoforms at endogenous levels. In addition, they pave the way for difficult experiments such as tissue-specific allele switching and functional analysis in post-mitotic or polyploid cells. Therefore, our method retains the advantages of homologous recombination while capitalising on the mutagenic power of CRISPR.
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38
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Beckett K, Monier S, Palmer L, Alexandre C, Green H, Bonneil E, Raposo G, Thibault P, Le Borgne R, Vincent JP. Drosophila S2 cells secrete wingless on exosome-like vesicles but the wingless gradient forms independently of exosomes. Traffic 2012; 14:82-96. [PMID: 23035643 DOI: 10.1111/tra.12016] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 10/01/2012] [Accepted: 10/05/2012] [Indexed: 11/28/2022]
Abstract
Wingless acts as a morphogen in Drosophila wing discs, where it specifies cell fates and controls growth several cell diameters away from its site of expression. Thus, despite being acylated and membrane associated, Wingless spreads in the extracellular space. Recent studies have focussed on identifying the route that Wingless follows in the secretory pathway and determining how it is packaged for release. We have found that, in medium conditioned by Wingless-expressing Drosophila S2 cells, Wingless is present on exosome-like vesicles and that this fraction activates signal transduction. Proteomic analysis shows that Wingless-containing exosome-like structures contain many Drosophila proteins that are homologous to mammalian exosome proteins. In addition, Evi, a multipass transmembrane protein, is also present on exosome-like vesicles. Using these exosome markers and a cell-based RNAi assay, we found that the small GTPase Rab11 contributes significantly to exosome production. This finding allows us to conclude from in vivo Rab11 knockdown experiments, that exosomes are unlikely to contribute to Wingless secretion and gradient formation in wing discs. Consistent with this conclusion, extracellularly tagged Evi expressed from a Bacterial Artificial Chromosome is not released from imaginal disc Wingless-expressing cells.
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Affiliation(s)
- Karen Beckett
- Division of Developmental Biology, MRC National Institute for Medical Research, Mill Hill, London, NW7 1AA, UK.
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39
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Abstract
Negative feedback is a widespread feature of signaling pathways. In an unexpected twist described in this issue, He and colleagues identify a membrane-tethered metalloprotease named Tiki that inhibits Wnt signaling by removing an essential eight-residue fragment from Wnt itself.
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40
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Baena-Lopez LA, Nojima H, Vincent JP. Integration of morphogen signalling within the growth regulatory network. Curr Opin Cell Biol 2012; 24:166-72. [PMID: 22257639 DOI: 10.1016/j.ceb.2011.12.010] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 12/06/2011] [Accepted: 12/14/2011] [Indexed: 11/27/2022]
Abstract
The need to coordinate patterning and growth has been appreciated for many years. The logic that enables seamless integration of the relevant inputs is beginning to be elucidated, particularly in wing imaginal discs of Drosophila. In this tissue, multiple regulatory layers involving the two morphogens Wingless and Dpp, the wing-specific determinant, Vestigial, and the Hippo pathway, converge to regulate growth. Intricate cross-regulation between these components may explain why, at the local level, there is no direct correlation between growth and the graded signalling activity of Wingless and Dpp, despite the requirement of these two pathways for growth.
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41
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Vincent JP, Kolahgar G, Gagliardi M, Piddini E. Steep differences in wingless signaling trigger Myc-independent competitive cell interactions. Dev Cell 2011; 21:366-74. [PMID: 21839923 PMCID: PMC3209557 DOI: 10.1016/j.devcel.2011.06.021] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Revised: 04/17/2011] [Accepted: 06/17/2011] [Indexed: 11/02/2022]
Abstract
Wnt signaling is a key regulator of development that is often associated with cancer. Wingless, a Drosophila Wnt homolog, has been reported to be a survival factor in wing imaginal discs. However, we found that prospective wing cells survive in the absence of Wingless as long as they are not surrounded by Wingless-responding cells. Moreover, local autonomous overactivation of Wg signaling (as a result of a mutation in APC or axin) leads to the elimination of surrounding normal cells. Therefore, relative differences in Wingless signaling lead to competitive cell interactions. This process does not involve Myc, a well-established cell competition factor. It does, however, require Notum, a conserved secreted feedback inhibitor of Wnt signaling. We suggest that Notum could amplify local differences in Wingless signaling, thus serving as an early trigger of Wg signaling-dependent competition.
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Affiliation(s)
- Jean-Paul Vincent
- MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, UK.
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Kolahgar G, Bardet PL, Langton PF, Alexandre C, Vincent JP. Apical deficiency triggers JNK-dependent apoptosis in the embryonic epidermis of Drosophila. Development 2011; 138:3021-31. [PMID: 21693518 DOI: 10.1242/dev.059980] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Epithelial homeostasis and the avoidance of diseases such as cancer require the elimination of defective cells by apoptosis. Here, we investigate how loss of apical determinants triggers apoptosis in the embryonic epidermis of Drosophila. Transcriptional profiling and in situ hybridisation show that JNK signalling is upregulated in mutants lacking Crumbs or other apical determinants. This leads to transcriptional activation of the pro-apoptotic gene reaper and to apoptosis. Suppression of JNK signalling by overexpression of Puckered, a feedback inhibitor of the pathway, prevents reaper upregulation and apoptosis. Moreover, removal of endogenous Puckered leads to ectopic reaper expression. Importantly, disruption of the basolateral domain in the embryonic epidermis does not trigger JNK signalling or apoptosis. We suggest that apical, not basolateral, integrity could be intrinsically required for the survival of epithelial cells. In apically deficient embryos, JNK signalling is activated throughout the epidermis. Yet, in the dorsal region, reaper expression is not activated and cells survive. One characteristic of these surviving cells is that they retain discernible adherens junctions despite the apical deficit. We suggest that junctional integrity could restrain the pro-apoptotic influence of JNK signalling.
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Affiliation(s)
- Golnar Kolahgar
- MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London, UK
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Affiliation(s)
- David Strutt
- Medical Research Council (MRC) Centre for Developmental and Biomedical Genetics, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Jean-Paul Vincent
- MRC National Institute for Medical Research, The Ridgeway, London NW7 1AA, UK
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Wendler F, Gillingham AK, Sinka R, Rosa-Ferreira C, Gordon DE, Franch-Marro X, Peden AA, Vincent JP, Munro S. A genome-wide RNA interference screen identifies two novel components of the metazoan secretory pathway. EMBO J 2010; 29:304-14. [PMID: 19942856 PMCID: PMC2824459 DOI: 10.1038/emboj.2009.350] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2009] [Accepted: 11/02/2009] [Indexed: 02/01/2023] Open
Abstract
Genetic screens in the yeast Saccharomyces cerevisiae have identified many proteins involved in the secretory pathway, most of which have orthologues in higher eukaryotes. To investigate whether there are additional proteins that are required for secretion in metazoans but are absent from yeast, we used genome-wide RNA interference (RNAi) to look for genes required for secretion of recombinant luciferase from Drosophila S2 cells. This identified two novel components of the secretory pathway that are conserved from humans to plants. Gryzun is distantly related to, but distinct from, the Trs130 subunit of the TRAPP complex but is absent from S. cerevisiae. RNAi of human Gryzun (C4orf41) blocks Golgi exit. Kish is a small membrane protein with a previously uncharacterised orthologue in yeast. The screen also identified Drosophila orthologues of almost 60% of the yeast genes essential for secretion. Given this coverage, the small number of novel components suggests that contrary to previous indications the number of essential core components of the secretory pathway is not much greater in metazoans than in yeasts.
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Affiliation(s)
- Franz Wendler
- MRC National Institute for Medical Research, London, UK
| | | | - Rita Sinka
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | | | - David E Gordon
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | | | - Andrew A Peden
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | | | - Sean Munro
- MRC Laboratory of Molecular Biology, Cambridge, UK
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Vincent JP, VanHook AM. Science Signaling
Podcast: 6 October 2009. Sci Signal 2009. [DOI: 10.1126/scisignal.291pc17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Graded distribution of Wingless is not required for cell proliferation in the fly wing disc.
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Affiliation(s)
- Jean-Paul Vincent
- Department of Developmental Neurobiology, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 IAA, UK
| | - Annalisa M. VanHook
- Science Signaling, American Association for the Advancement of Science, 1200 New York Avenue, N.W., Washington, DC 20005, USA
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Abstract
Morphogens form concentration gradients that organize patterns of cells and control growth. It has been suggested that, rather than the intensity of morphogen signaling, it is its gradation that is the relevant modulator of cell proliferation. According to this view, the ability of morphogens to regulate growth during development depends on their graded distributions. Here, we describe an experimental test of this model for Wingless, one of the key organizers of wing development in Drosophila. Maximal Wingless signaling suppresses cellular proliferation. In contrast, we found that moderate and uniform amounts of exogenous Wingless, even in the absence of endogenous Wingless, stimulated proliferative growth. Beyond a few cell diameters from the source, Wingless was relatively constant in abundance and thus provided a homogeneous growth-promoting signal. Although morphogen signaling may act in combination with as yet uncharacterized graded growth-promoting pathways, we suggest that the graded nature of morphogen signaling is not required for proliferation, at least in the developing Drosophila wing, during the main period of growth.
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Affiliation(s)
- Luis Alberto Baena-Lopez
- Department of Developmental Neurobiology, MRC National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
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Kolahgar G, Bardet PL, Vincent JP. 13-P134 Epithelial integrity and cell survival in the embryonic epidermis of Drosophila. Mech Dev 2009. [DOI: 10.1016/j.mod.2009.06.607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Hogan C, Dupré-Crochet S, Norman M, Kajita M, Zimmermann C, Pelling AE, Piddini E, Baena-López LA, Vincent JP, Itoh Y, Hosoya H, Pichaud F, Fujita Y. Characterization of the interface between normal and transformed epithelial cells. Nat Cell Biol 2009; 11:460-7. [PMID: 19287376 DOI: 10.1038/ncb1853] [Citation(s) in RCA: 253] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Accepted: 12/12/2008] [Indexed: 11/09/2022]
Abstract
In most cancers, transformation begins in a single cell in an epithelial cell sheet. However, it is not known what happens at the interface between non-transformed (normal) and transformed cells once the initial transformation has occurred. Using Madin-Darby canine kidney (MDCK) epithelial cells that express constitutively active, oncogenic Ras (Ras(V12)) in a tetracycline-inducible system, we investigated the cellular processes arising at the interface between normal and transformed cells. We show that two independent phenomena occur in a non-cell-autonomous manner: when surrounded by normal cells, Ras(V12) cells are either apically extruded from the monolayer, or form dynamic basal protrusions and invade the basal matrix. Neither apical extrusion nor basal protrusion formation is observed when Ras(V12) cells are surrounded by other Ras(V12) cells. We show that Cdc42 and ROCK (also known as Rho kinase) have vital roles in these processes. We also demonstrate that E-cadherin knockdown in normal cells surrounding Ras(V12) cells reduces the frequency of apical extrusion, while promoting basal protrusion formation and invasion. These results indicate that Ras(V12)-transformed cells are able to recognize differences between normal and transformed cells, and consequently leave epithelial sheets either apically or basally, in a cell-context-dependent manner.
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Piddini E, Vincent JP. Interpretation of the wingless gradient requires signaling-induced self-inhibition. Cell 2009; 136:296-307. [PMID: 19167331 DOI: 10.1016/j.cell.2008.11.036] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 09/24/2008] [Accepted: 11/21/2008] [Indexed: 11/30/2022]
Abstract
In a classical view of development, a cell can acquire positional information by reading the local concentration of a morphogen independently of its neighbors. Accordingly, in Drosophila, the morphogen Wingless produced in the wing's prospective distal region activates target genes in a dose-dependent fashion to organize the proximodistal pattern. Here, we show that, in parallel, Wingless triggers two nonautonomous inhibitory programs that play an important role in the establishment of positional information. Cells flanking the source of Wingless produce a negative signal (encoded by notum) that inhibits Wingless signaling in nearby cells. Additionally, in response to Wingless, all prospective wing cells produce an unidentified signal that dampens target gene expression in surrounding cells. Thus, cells influence each other's response to Wingless through at least two modes of lateral inhibition. Without lateral inhibition, some cells acquire ectopic fates. Lateral inhibition may be a general mechanism behind the interpretation of morphogen gradients.
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Affiliation(s)
- Eugenia Piddini
- MRC National Institute for Medical Research, Mill Hill, London NW7 1AA, UK
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