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Maib H, Adarska P, Hunton R, Vines JH, Strutt D, Bottanelli F, Murray DH. Recombinant biosensors for multiplex and super-resolution imaging of phosphoinositides. J Cell Biol 2024; 223:e202310095. [PMID: 38578646 PMCID: PMC10996583 DOI: 10.1083/jcb.202310095] [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] [Received: 10/23/2023] [Revised: 02/16/2024] [Accepted: 03/11/2024] [Indexed: 04/06/2024] Open
Abstract
Phosphoinositides are a small family of phospholipids that act as signaling hubs and key regulators of cellular function. Detecting their subcellular distribution is crucial to gain insights into membrane organization and is commonly done by the overexpression of biosensors. However, this leads to cellular perturbations and is challenging in systems that cannot be transfected. Here, we present a toolkit for the reliable, fast, multiplex, and super-resolution detection of phosphoinositides in fixed cells and tissue, based on recombinant biosensors with self-labeling SNAP tags. These are highly specific and reliably visualize the subcellular distributions of phosphoinositides across scales, from 2D or 3D cell culture to Drosophila tissue. Further, these probes enable super-resolution approaches, and using STED microscopy, we reveal the nanoscale organization of PI(3)P on endosomes and PI(4)P on the Golgi. Finally, multiplex staining reveals an unexpected presence of PI(3,5)P2-positive membranes in swollen lysosomes following PIKfyve inhibition. This approach enables the versatile, high-resolution visualization of multiple phosphoinositide species in an unprecedented manner.
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Affiliation(s)
- Hannes Maib
- School of Biosciences, University of Sheffield, Sheffield, UK
| | - Petia Adarska
- Institut für Biochemie, Freie Universität Berlin, Berlin, Germany
| | - Robert Hunton
- School of Biosciences, University of Sheffield, Sheffield, UK
| | - James H. Vines
- School of Biosciences, University of Sheffield, Sheffield, UK
| | - David Strutt
- School of Biosciences, University of Sheffield, Sheffield, UK
| | | | - David H. Murray
- Division of Molecular, Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee, UK
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2
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Strutt H, Warrington S, Madathil ACK, Langenhan T, Strutt D. Molecular symmetry breaking in the Frizzled-dependent planar polarity pathway. Curr Biol 2023; 33:5340-5354.e6. [PMID: 37995695 DOI: 10.1016/j.cub.2023.10.071] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 10/03/2023] [Accepted: 10/31/2023] [Indexed: 11/25/2023]
Abstract
The core planar polarity pathway consists of six proteins that form asymmetric intercellular complexes that segregate to opposite cell ends in developing tissues and specify polarized cell structures or behaviors. Within these complexes, the atypical cadherin Flamingo localizes on both sides of intercellular junctions, where it interacts homophilically in trans via its cadherin repeats, whereas the transmembrane proteins Frizzled and Strabismus localize to the opposite sides of apposing junctions. However, the molecular mechanisms underlying the formation of such asymmetric complexes are poorly understood. Using a novel tissue culture system, we determine the minimum requirements for asymmetric complex assembly in the absence of confounding feedback mechanisms. We show that complexes are intrinsically asymmetric and that an interaction of Frizzled and Flamingo in one cell with Flamingo in the neighboring cell is the key symmetry-breaking step. In contrast, Strabismus is unable to promote homophilic Flamingo trans binding and is only recruited into complexes once Frizzled has entered on the opposite side. This interaction with Strabismus requires intact intracellular loops of the seven-pass transmembrane domain of Flamingo. Once recruited, Strabismus stabilizes the intercellular complexes together with the three cytoplasmic core proteins. We propose a model whereby Flamingo exists in a closed conformation and binding of Frizzled in one cell results in a conformational change that allows its cadherin repeats to interact with a Flamingo molecule in the neighboring cell. Flamingo in the adjacent cell then undergoes a further change in the seven-pass transmembrane region that promotes the recruitment of Strabismus.
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Affiliation(s)
- Helen Strutt
- School of Biosciences, University of Sheffield, Firth Court, Sheffield S10 2TN, UK.
| | - Samantha Warrington
- School of Biosciences, University of Sheffield, Firth Court, Sheffield S10 2TN, UK
| | | | - Tobias Langenhan
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, 04103 Leipzig, Germany
| | - David Strutt
- School of Biosciences, University of Sheffield, Firth Court, Sheffield S10 2TN, UK.
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3
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Moreno MR, Hunton R, Strutt D, Bulgakova NA. Deciphering the roles of cell shape and Fat and Dachsous planar polarity in arranging the Drosophila apical microtubule network through quantitative image analysis. Mol Biol Cell 2023; 34:ar55. [PMID: 36735484 DOI: 10.1091/mbc.e22-09-0442] [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: 02/04/2023] Open
Abstract
In epithelial cells, planar polarisation of subapical microtubule networks is thought to be important for both breaking cellular symmetry and maintaining the resulting cellular polarity. Studies in the Drosophila pupal wing and other tissues have suggested two alternative mechanisms for specifying network polarity. On one hand mechanical strain and/or cell shape have been implicated as key determinants, on the other the Fat-Dachsous planar polarity pathway has been suggested to be the primary polarising cue. Using quantitative image analysis in the pupal wing, we reassess these models. We found that cell shape was a strong predictor of microtubule organisation in the developing wing epithelium. Conversely Fat-Dachsous polarity cues do not play any direct role in the organisation of the subapical microtubule network, despite being able to weakly recruit the microtubule minus-end capping protein Patronin to cell boundaries. We conclude that any effect of Fat-Dachsous on microtubule polarity is likely to be indirect, via their known ability to regulate cell shape.
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Affiliation(s)
- Miguel Ramírez Moreno
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK.,Bateson Centre, University of Sheffield, Sheffield S10 2TN, UK.,Present address: School of Biological Sciences, University of Southampton, SO17 1BJ, UK
| | - Robert Hunton
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - David Strutt
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Natalia A Bulgakova
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK.,Bateson Centre, University of Sheffield, Sheffield S10 2TN, UK
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4
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Brittle A, Warrington SJ, Strutt H, Manning E, Tan SE, Strutt D. Distinct mechanisms of planar polarization by the core and Fat-Dachsous planar polarity pathways in the Drosophila wing. Cell Rep 2022; 40:111419. [PMID: 36170824 PMCID: PMC9631118 DOI: 10.1016/j.celrep.2022.111419] [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] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 08/29/2022] [Accepted: 09/02/2022] [Indexed: 11/29/2022] Open
Abstract
Planar polarity describes the coordinated polarization of cells within a tissue plane, and in animals can be determined by the “core” or Fat-Dachsous pathways. Current models for planar polarity establishment involve two components: tissue-level “global” cues that determine the overall axis of polarity and cell-level feedback-mediated cellular polarity amplification. Here, we investigate the contributions of global cues versus cellular feedback amplification in the core and Fat-Dachsous pathways during Drosophila pupal wing development. We present evidence that these pathways generate planar polarity via distinct mechanisms. Core pathway function is consistent with strong feedback capable of self-organizing cell polarity, which can then be aligned with the tissue axis via weak or transient global cues. Conversely, generation of cell polarity by the Ft-Ds pathway depends on strong global cues in the form of graded patterns of gene expression, which can then be amplified by weak feedback mechanisms. The core and Fat-Dachsous planar polarity pathways function via distinct mechanisms The core can self-organize planar polarity and be oriented by weak upstream cues Fat-Dachsous are oriented by strong gradient cues but show poor self-organization
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Affiliation(s)
- Amy Brittle
- School of Biosciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | | | - Helen Strutt
- School of Biosciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Elizabeth Manning
- School of Biosciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Su Ee Tan
- School of Biosciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - David Strutt
- School of Biosciences, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
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5
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Mieszczanek J, Strutt H, Rutherford TJ, Strutt D, Bienz M, Gammons MV. Selective function of the PDZ domain of Dishevelled in noncanonical Wnt signalling. J Cell Sci 2022; 135:jcs259547. [PMID: 35542970 PMCID: PMC9234668 DOI: 10.1242/jcs.259547] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 04/28/2022] [Indexed: 11/29/2022] Open
Abstract
Dishevelled is a cytoplasmic hub that transduces Wnt signals to cytoplasmic effectors, which can be broadly characterised as canonical (β-catenin dependent) and noncanonical, to specify cell fates and behaviours during development. To transduce canonical Wnt signals, Dishevelled binds to the intracellular face of Frizzled through its DEP domain and polymerises through its DIX domain to assemble dynamic signalosomes. Dishevelled also contains a PDZ domain, whose function remains controversial. Here, we use genome editing to delete the PDZ domain-encoding region from Drosophila dishevelled. Canonical Wingless signalling is entirely normal in these deletion mutants; however, they show defects in multiple contexts controlled by noncanonical Wnt signalling, such as planar polarity. We use nuclear magnetic resonance spectroscopy to identify bona fide PDZ-binding motifs at the C termini of different polarity proteins. Although deletions of these motifs proved aphenotypic in adults, we detected changes in the proximodistal distribution of the polarity protein Flamingo (also known as Starry night) in pupal wings that suggest a modulatory role of these motifs in polarity signalling. We also provide new genetic evidence that planar polarity relies on the DEP-dependent recruitment of Dishevelled to the plasma membrane by Frizzled.
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Affiliation(s)
- Juliusz Mieszczanek
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Helen Strutt
- University of Sheffield, School of Biosciences,Firth Court,Western Bank, Sheffield, S10 2TN, UK
| | - Trevor J. Rutherford
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - David Strutt
- University of Sheffield, School of Biosciences,Firth Court,Western Bank, Sheffield, S10 2TN, UK
| | - Mariann Bienz
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge, CB2 0QH, UK
| | - Melissa V. Gammons
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge, CB2 0QH, UK
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Warrington SJ, Strutt H, Strutt D. Use of Fluorescence Recovery After Photobleaching (FRAP) to Measure In Vivo Dynamics of Cell Junction-Associated Polarity Proteins. Methods Mol Biol 2022; 2438:1-30. [PMID: 35147932 DOI: 10.1007/978-1-0716-2035-9_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [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] [Indexed: 10/19/2022]
Abstract
Here, we present a detailed protocol for fluorescence recovery after photobleaching (FRAP) to measure the dynamics of junctional populations of proteins in living tissue. Specifically, we describe how to perform FRAP in Drosophila pupal wings on fluorescently tagged core planar polarity proteins, which exhibit relatively slow junctional turnover. We provide a step-by-step practical guide to performing FRAP, and list a series of controls and optimizations to do before conducting a FRAP experiment. Finally, we describe how to present the FRAP data for publication.
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Affiliation(s)
| | - Helen Strutt
- School of Biosciences, University of Sheffield, Sheffield, UK
| | - David Strutt
- School of Biosciences, University of Sheffield, Sheffield, UK.
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Tan SE, Tan W, Fisher K, Strutt D. QuantifyPolarity, a new tool-kit for measuring planar polarized protein distributions and cell properties in developing tissues. Development 2021; 148:272072. [PMID: 34351416 PMCID: PMC8451067 DOI: 10.1242/dev.198952] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [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] [Received: 11/24/2020] [Accepted: 07/26/2021] [Indexed: 11/24/2022]
Abstract
The coordination of cells or structures within the plane of a tissue is known as planar polarization. It is often governed by the asymmetric distribution of planar polarity proteins within cells. A number of quantitative methods have been developed to provide a readout of planar polarized protein distributions. However, previous planar polarity quantification methods can be affected by variation in cell geometry. Hence, we developed a novel planar polarity quantification method based on Principal Component Analysis (PCA) that is shape insensitive. Here, we compare this method with other state-of-the-art methods on simulated models and biological datasets. We found that the PCA method performs robustly in quantifying planar polarity independently of variation in cell geometry and other image conditions. We designed a user-friendly graphical user interface called QuantifyPolarity, equipped with three polarity methods for automated quantification of polarity. QuantifyPolarity also provides tools to quantify cell morphology and packing geometry, allowing the relationship of these characteristics to planar polarization to be investigated. This tool enables experimentalists with no prior computational expertise to perform high-throughput cell polarity and shape analysis automatically and efficiently. Summary: We present a novel planar polarity quantification method based on Principal Component Analysis that performs robustly in quantifying planar polarity independently of variation in cell geometry and other image properties.
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Affiliation(s)
- Su Ee Tan
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Weijie Tan
- School of Computer Science, University of Nottingham, Jubilee Campus, Wollaton Road, Nottingham, NG8 1BB, UK
| | - Katherine Fisher
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - David Strutt
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
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8
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Strutt H, Strutt D. How do the Fat-Dachsous and core planar polarity pathways act together and independently to coordinate polarized cell behaviours? Open Biol 2021; 11:200356. [PMID: 33561385 PMCID: PMC8061702 DOI: 10.1098/rsob.200356] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Planar polarity describes the coordinated polarization of cells within the plane of a tissue. This is controlled by two main pathways in Drosophila: the Frizzled-dependent core planar polarity pathway and the Fat–Dachsous pathway. Components of both of these pathways become asymmetrically localized within cells in response to long-range upstream cues, and form intercellular complexes that link polarity between neighbouring cells. This review examines if and when the two pathways are coupled, focusing on the Drosophila wing, eye and abdomen. There is strong evidence that the pathways are molecularly coupled in tissues that express a specific isoform of the core protein Prickle, namely Spiny-legs. However, in other contexts, the linkages between the pathways are indirect. We discuss how the two pathways act together and independently to mediate a diverse range of effects on polarization of cell structures and behaviours.
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Affiliation(s)
- Helen Strutt
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - David Strutt
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
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9
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Abstract
The core planar polarity proteins are essential mediators of tissue morphogenesis, controlling both the polarised production of cellular structures and polarised tissue movements. During development the core proteins promote planar polarisation by becoming asymmetrically localised to opposite cell edges within epithelial tissues, forming intercellular protein complexes that coordinate polarity between adjacent cells. Here we describe a novel protein complex that regulates the asymmetric localisation of the core proteins in the Drosophila pupal wing. DAnkrd49 (an ankyrin repeat protein) and Bride of Doubletime (Bdbt, a non-canonical FK506 binding protein family member) physically interact, and regulate each other’s levels in vivo. Loss of either protein results in a reduction in core protein asymmetry and disruption of the placement of trichomes at the distal edge of pupal wing cells. Post-translational modifications are thought to be important for the regulation of core protein behaviour and their sorting to opposite cell edges. Consistent with this, we find that loss of DAnkrd49 or Bdbt leads to reduced phosphorylation of the core protein Dishevelled and to decreased Dishevelled levels both at cell junctions and in the cytoplasm. Bdbt has previously been shown to regulate activity of the kinase Discs Overgrown (Dco, also known as Doubletime or Casein Kinase Iε), and Dco itself has been implicated in regulating planar polarity by phosphorylating Dsh as well as the core protein Strabismus. We demonstrate that DAnkrd49 and Bdbt act as dominant suppressors of Dco activity. These findings support a model whereby Bdbt and DAnkrd49 act together to modulate the activity of Dco during planar polarity establishment. In many animal tissues, sheets of cells are polarised in the plane of the tissue, which is evident by the production of polarised structures, such as hairs on the fly wing that point in the same direction or cilia that beat in the same direction. One group of proteins controlling this coordinated polarity are the core planar polarity proteins, which localise asymmetrically within cells such that some core proteins localise to one cell end and others to the opposite cell end. It is thought that modifications such as phosphorylation may locally regulate core protein stability, and this promotes sorting of proteins to different cell ends. We identify two proteins, DAnkrd49 and Bdbt, that form a complex and regulate core protein asymmetry. Loss of either protein causes a reduction in overall levels of the core protein Dishevelled (Dsh), and a reduction in its phosphorylation. We provide evidence that the effect on core protein asymmetry is mediated via regulation of the kinase activity of Discs overgrown (Dco, also known as Doubletime/Casein Kinase Iε) by DAnkrd49 and Bdbt. We propose that modulation of Dco activity by DAnkrd49 and Bdbt is a key step in the sorting of core proteins to opposite cell ends.
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Affiliation(s)
- Helen Strutt
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, United Kingdom
- * E-mail: (HS); (DS)
| | - David Strutt
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, United Kingdom
- * E-mail: (HS); (DS)
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Gerondopoulos A, Strutt H, Stevenson NL, Sobajima T, Levine TP, Stephens DJ, Strutt D, Barr FA. Planar Cell Polarity Effector Proteins Inturned and Fuzzy Form a Rab23 GEF Complex. Curr Biol 2019; 29:3323-3330.e8. [PMID: 31564489 PMCID: PMC6864590 DOI: 10.1016/j.cub.2019.07.090] [Citation(s) in RCA: 24] [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: 06/27/2019] [Revised: 07/26/2019] [Accepted: 07/31/2019] [Indexed: 01/12/2023]
Abstract
A subset of Rab GTPases have been implicated in cilium formation in cultured mammalian cells [1-6]. Rab11 and Rab8, together with their GDP-GTP exchange factors (GEFs), TRAPP-II and Rabin8, promote recruitment of the ciliary vesicle to the mother centriole and its subsequent maturation, docking, and fusion with the cell surface [2-5]. Rab23 has been linked to cilium formation and membrane trafficking at mature cilia [1, 7, 8]; however, the identity of the GEF pathway activating Rab23, a member of the Rab7 subfamily of Rabs, remains unclear. Longin-domain-containing complexes have been shown to act as GEFs for Rab7 subfamily GTPases [9-12]. Here, we show that Inturned and Fuzzy, proteins previously implicated as planar cell polarity (PCP) effectors and in developmentally regulated cilium formation [13, 14], contain multiple longin domains characteristic of the Mon1-Ccz1 family of Rab7 GEFs and form a specific Rab23 GEF complex. In flies, loss of Rab23 function gave rise to defects in planar-polarized trichome formation consistent with this biochemical relationship. In cultured human and mouse cells, Inturned and Fuzzy localized to the basal body and proximal region of cilia, and cilium formation was compromised by depletion of either Inturned or Fuzzy. Cilium formation arrested after docking of the ciliary vesicle to the mother centriole but prior to axoneme elongation and fusion of the ciliary vesicle and plasma membrane. These findings extend the family of longin domain GEFs and define a molecular activity linking Rab23-regulated membrane traffic to cilia and planar cell polarity.
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Affiliation(s)
- Andreas Gerondopoulos
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Helen Strutt
- Department of Biomedical Science, University of Sheffield, Firth Court, Sheffield S10 2TN, UK
| | - Nicola L Stevenson
- School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Tomoaki Sobajima
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Tim P Levine
- Institute of Ophthalmology, University College London, 11-43 Bath St., London EC1V 9EL, UK
| | - David J Stephens
- School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - David Strutt
- Department of Biomedical Science, University of Sheffield, Firth Court, Sheffield S10 2TN, UK
| | - Francis A Barr
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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Chaudhary V, Hingole S, Frei J, Port F, Strutt D, Boutros M. Robust Wnt signaling is maintained by a Wg protein gradient and Fz2 receptor activity in the developing Drosophila wing. Development 2019; 146:dev174789. [PMID: 31399474 PMCID: PMC6703709 DOI: 10.1242/dev.174789] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [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: 12/09/2018] [Accepted: 07/10/2019] [Indexed: 12/19/2022]
Abstract
Wnts are secreted proteins that regulate cell fate during development of all metazoans. Wnt proteins were proposed to spread over several cells to activate signaling directly at a distance. In the Drosophila wing epithelium, an extracellular gradient of the Wnt1 homolog Wingless (Wg) was observed extending over several cells away from producing cells. Surprisingly, however, it was also shown that a membrane-tethered Neurotactin-Wg fusion protein (NRT-Wg) can largely replace endogenous Wg, leading to proper patterning of the wing. Therefore, the functional range of Wg and whether Wg spreading is required for correct tissue patterning remains controversial. Here, by capturing secreted Wg on cells away from the source, we show that Wg acts over a distance of up to 11 cell diameters to induce signaling. Furthermore, cells located outside the reach of extracellular Wg depend on the Frizzled2 receptor to maintain signaling. Frizzled2 expression is increased in the absence of Wg secretion and is required to maintain signaling and cell survival in NRT-wg wing discs. Together, these results provide insight into the mechanisms by which robust Wnt signaling is achieved in proliferating tissues.
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Affiliation(s)
- Varun Chaudhary
- German Cancer Research Center (DKFZ), Division Signaling and Functional Genomics and Department of Cell and Molecular Biology, Medical Faculty Mannheim, Heidelberg University, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
- Department of Biological Science, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal 462066, India
| | - Swapnil Hingole
- Department of Biological Science, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhauri, Bhopal 462066, India
| | - Jana Frei
- German Cancer Research Center (DKFZ), Division Signaling and Functional Genomics and Department of Cell and Molecular Biology, Medical Faculty Mannheim, Heidelberg University, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
| | - Fillip Port
- German Cancer Research Center (DKFZ), Division Signaling and Functional Genomics and Department of Cell and Molecular Biology, Medical Faculty Mannheim, Heidelberg University, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
| | - David Strutt
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
| | - Michael Boutros
- German Cancer Research Center (DKFZ), Division Signaling and Functional Genomics and Department of Cell and Molecular Biology, Medical Faculty Mannheim, Heidelberg University, Im Neuenheimer Feld 580, 69120 Heidelberg, Germany
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Fisher KH, Strutt D, Fletcher AG. Experimental and Theoretical Evidence for Bidirectional Signaling via Core Planar Polarity Protein Complexes in Drosophila. iScience 2019; 17:49-66. [PMID: 31254741 PMCID: PMC6610702 DOI: 10.1016/j.isci.2019.06.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 03/21/2019] [Accepted: 06/12/2019] [Indexed: 12/21/2022] Open
Abstract
In developing tissues, sheets of cells become planar polarized, enabling coordination of cell behaviors. It has been suggested that "signaling" of polarity information between cells may occur either bidirectionally or monodirectionally between the molecules Frizzled (Fz) and Van Gogh (Vang). Using computational modeling we find that both bidirectional and monodirectional signaling models reproduce known non-autonomous phenotypes derived from patches of mutant tissue of key molecules but predict different phenotypes from double mutant tissue, which have previously given conflicting experimental results. Furthermore, we re-examine experimental phenotypes in the Drosophila wing, concluding that signaling is most likely bidirectional. Our modeling suggests that bidirectional signaling can be mediated either indirectly via bidirectional feedbacks between asymmetric intercellular protein complexes or directly via different affinities for protein binding in intercellular complexes, suggesting future avenues for investigation. Our findings offer insight into mechanisms of juxtacrine cell signaling and how tissue-scale properties emerge from individual cell behaviors.
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Affiliation(s)
- Katherine H Fisher
- Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - David Strutt
- Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK.
| | - Alexander G Fletcher
- School of Mathematics and Statistics, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH, UK; Bateson Centre, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK.
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13
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Strutt H, Gamage J, Strutt D. Reciprocal action of Casein Kinase Iε on core planar polarity proteins regulates clustering and asymmetric localisation. eLife 2019; 8:45107. [PMID: 31090542 PMCID: PMC6542583 DOI: 10.7554/elife.45107] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [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: 01/11/2019] [Accepted: 05/14/2019] [Indexed: 01/08/2023] Open
Abstract
The conserved core planar polarity pathway is essential for coordinating polarised cell behaviours and the formation of polarised structures such as cilia and hairs. Core planar polarity proteins localise asymmetrically to opposite cell ends and form intercellular complexes that link the polarity of neighbouring cells. This asymmetric segregation is regulated by phosphorylation through poorly understood mechanisms. We show that loss of phosphorylation of the core protein Strabismus in the Drosophila pupal wing increases its stability and promotes its clustering at intercellular junctions, and that Prickle negatively regulates Strabismus phosphorylation. Additionally, loss of phosphorylation of Dishevelled - which normally localises to opposite cell edges to Strabismus - reduces its stability at junctions. Moreover, both phosphorylation events are independently mediated by Casein Kinase Iε. We conclude that Casein Kinase Iε phosphorylation acts as a switch, promoting Strabismus mobility and Dishevelled immobility, thus enhancing sorting of these proteins to opposite cell edges.
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Affiliation(s)
- Helen Strutt
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - Jessica Gamage
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
| | - David Strutt
- Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom
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Strutt H, Langton PF, Pearson N, McMillan KJ, Strutt D, Cullen PJ. Retromer Controls Planar Polarity Protein Levels and Asymmetric Localization at Intercellular Junctions. Curr Biol 2019; 29:484-491.e6. [PMID: 30661800 PMCID: PMC6370945 DOI: 10.1016/j.cub.2018.12.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [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: 08/02/2018] [Revised: 11/15/2018] [Accepted: 12/14/2018] [Indexed: 11/12/2022]
Abstract
The coordinated polarization of cells in the plane of a tissue, termed planar polarity, is a characteristic feature of epithelial tissues [1]. In the fly wing, trichome positioning is dependent on the core planar polarity proteins adopting asymmetric subcellular localizations at apical junctions, where they form intercellular complexes that link neighboring cells [1-3]. Specifically, the seven-pass transmembrane protein Frizzled and the cytoplasmic proteins Dishevelled and Diego localize to distal cell ends, the four-pass transmembrane protein Strabismus and the cytoplasmic protein Prickle localize proximally, and the seven-pass transmembrane spanning atypical cadherin Flamingo localizes both proximally and distally. To establish asymmetry, these core proteins are sorted from an initially uniform distribution; however, the mechanisms underlying this polarized trafficking remain poorly understood. Here, we describe the identification of retromer, a master controller of endosomal recycling [4-6], as a key component regulating core planar polarity protein localization in Drosophila. Through generation of mutants, we verify that loss of the retromer-associated Snx27 cargo adaptor, but notably not components of the Wash complex, reduces junctional levels of the core proteins Flamingo and Strabismus in the developing wing. We establish that Snx27 directly associates with Flamingo via its C-terminal PDZ binding motif, and we show that Snx27 is essential for normal Flamingo trafficking. We conclude that Wash-independent retromer function and the Snx27 cargo adaptor are important components in the endosomal recycling of Flamingo and Strabismus back to the plasma membrane and thus contribute to the establishment and maintenance of planar polarization.
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Affiliation(s)
- Helen Strutt
- Department of Biomedical Science, Firth Court, University of Sheffield, Sheffield S10 2TN, UK
| | - Paul F Langton
- School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Neil Pearson
- School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Kirsty J McMillan
- School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - David Strutt
- Department of Biomedical Science, Firth Court, University of Sheffield, Sheffield S10 2TN, UK.
| | - Peter J Cullen
- School of Biochemistry, Biomedical Sciences Building, University of Bristol, Bristol BS8 1TD, UK.
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15
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Fisher KH, Strutt D. A theoretical framework for planar polarity establishment through interpretation of graded cues by molecular bridges. Development 2019; 146:146/3/dev168955. [PMID: 30709912 PMCID: PMC6382004 DOI: 10.1242/dev.168955] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [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: 01/05/2023]
Abstract
Planar polarity is a widespread phenomenon found in many tissues, allowing cells to coordinate morphogenetic movements and function. A common feature of animal planar polarity systems is the formation of molecular bridges between cells, which become polarised along a tissue axis. We propose that these bridges provide a general mechanism by which cells interpret different forms of tissue gradients to coordinate directional information. We illustrate this using a generalised and consistent modelling framework, providing a conceptual basis for understanding how different mechanisms of gradient function can generate planar polarity. We make testable predictions of how different gradient mechanisms can influence polarity direction. Summary: This Hypothesis uses a theoretical framework to explore how molecular bridges provide a general mechanism to interpret different forms of tissue gradients to establish planar polarity.
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Affiliation(s)
- Katherine H Fisher
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - David Strutt
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
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16
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Ressurreição M, Warrington S, Strutt D. Rapid Disruption of Dishevelled Activity Uncovers an Intercellular Role in Maintenance of Prickle in Core Planar Polarity Protein Complexes. Cell Rep 2018; 25:1415-1424.e6. [PMID: 30403998 PMCID: PMC6231328 DOI: 10.1016/j.celrep.2018.10.039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [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: 06/13/2018] [Revised: 09/17/2018] [Accepted: 10/09/2018] [Indexed: 12/24/2022] Open
Abstract
Planar polarity, the coordinated polarization of cells in the plane of a tissue, is important for normal tissue development and function. Proteins of the core planar polarity pathway become asymmetrically localized at the junctions between cells to form intercellular complexes that coordinate planar polarity between cell neighbors. Here, we combine tools to rapidly disrupt the activity of the core planar polarity protein Dishevelled, with quantitative measurements of protein dynamics and levels, and mosaic analysis, to investigate Dishevelled function in maintenance of planar polarity. We provide mechanistic insight into the hierarchical relationship of Dishevelled with other members of the core planar polarity complex. Notably, we show that removal of Dishevelled in one cell causes rapid release of Prickle into the cytoplasm in the neighboring cell. This release of Prickle generates a self-propagating wave of planar polarity complex destabilization across the tissue. Thus, Dishevelled actively maintains complex integrity across intercellular junctions. Inducible genetic tools can efficiently disrupt Dishevelled activity in vivo Dishevelled activity continuously promotes core planar polarity complex stability Prickle is maintained in intercellular complexes cell non-autonomously by Dishevelled Unbound Prickle results in intercellular propagation of complex destabilization
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Affiliation(s)
- Margarida Ressurreição
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Samantha Warrington
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - David Strutt
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK.
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17
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Strutt H, Gamage J, Strutt D. Robust Asymmetric Localization of Planar Polarity Proteins Is Associated with Organization into Signalosome-like Domains of Variable Stoichiometry. Cell Rep 2017; 17:2660-2671. [PMID: 27926869 PMCID: PMC5177602 DOI: 10.1016/j.celrep.2016.11.021] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [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: 07/12/2016] [Revised: 09/21/2016] [Accepted: 11/02/2016] [Indexed: 11/18/2022] Open
Abstract
In developing epithelia, the core planar polarity proteins physically interact with each other and localize asymmetrically at opposite cell ends, forming intercellular complexes that link the polarity of neighboring cells. Using quantitative imaging to examine the composition of the core protein complex in vivo, we find that complex composition is unexpectedly plastic. The transmembrane proteins Frizzled and Flamingo form a stoichiometric nucleus in the complex, while the relative levels of the other four core proteins can vary independently. Exploring the functional consequences of this, we show that robust cell polarization is achieved over a range of complex stoichiometries but is dependent on maintaining appropriate levels of the components Frizzled and Strabismus. We propose that the core proteins assemble into signalosome-like structures, where stable association is not dependent on one-to-one interactions with binding partners, and signaling functions can act over a wide range of complex compositions.
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Affiliation(s)
- Helen Strutt
- Bateson Centre, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Jessica Gamage
- Bateson Centre, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - David Strutt
- Bateson Centre, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
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18
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Warrington SJ, Strutt H, Fisher KH, Strutt D. A Dual Function for Prickle in Regulating Frizzled Stability during Feedback-Dependent Amplification of Planar Polarity. Curr Biol 2017; 27:2784-2797.e3. [PMID: 28918952 PMCID: PMC5628951 DOI: 10.1016/j.cub.2017.08.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [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: 05/01/2017] [Revised: 07/12/2017] [Accepted: 08/07/2017] [Indexed: 11/18/2022]
Abstract
The core planar polarity pathway coordinates epithelial cell polarity during animal development, and loss of its activity gives rise to a range of defects, from aberrant morphogenetic cell movements to failure to correctly orient structures, such as hairs and cilia. The core pathway functions via a mechanism involving segregation of its protein components to opposite cells ends, where they form asymmetric intracellular complexes that couple cell-cell polarity. This segregation is a self-organizing process driven by feedback interactions between the core proteins themselves. Despite intense efforts, the molecular pathways underlying feedback have proven difficult to elucidate using conventional genetic approaches. Here we investigate core protein function during planar polarization of the Drosophila wing by combining quantitative measurements of protein dynamics with loss-of-function genetics, mosaic analysis, and temporal control of gene expression. Focusing on the key core protein Frizzled, we show that its stable junctional localization is promoted by the core proteins Strabismus, Dishevelled, Prickle, and Diego. In particular, we show that the stabilizing function of Prickle on Frizzled requires Prickle activity in neighboring cells. Conversely, Prickle in the same cell has a destabilizing effect on Frizzled. This destabilizing activity is dependent on the presence of Dishevelled and blocked in the absence of Dynamin and Rab5 activity, suggesting an endocytic mechanism. Overall, our approach reveals for the first time essential in vivo stabilizing and destabilizing interactions of the core proteins required for self-organization of planar polarity.
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Affiliation(s)
- Samantha J Warrington
- Bateson Centre, Firth Court, University of Sheffield, Sheffield S10 2TN, UK; Department of Biomedical Science, Firth Court, University of Sheffield, Sheffield S10 2TN, UK
| | - Helen Strutt
- Bateson Centre, Firth Court, University of Sheffield, Sheffield S10 2TN, UK; Department of Biomedical Science, Firth Court, University of Sheffield, Sheffield S10 2TN, UK
| | - Katherine H Fisher
- Bateson Centre, Firth Court, University of Sheffield, Sheffield S10 2TN, UK; Department of Biomedical Science, Firth Court, University of Sheffield, Sheffield S10 2TN, UK
| | - David Strutt
- Bateson Centre, Firth Court, University of Sheffield, Sheffield S10 2TN, UK; Department of Biomedical Science, Firth Court, University of Sheffield, Sheffield S10 2TN, UK.
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19
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Warrington S, Strutt H, Strutt D. Establishing planar polarity through positive and negative interactions in the Drosophila wing. Mech Dev 2017. [DOI: 10.1016/j.mod.2017.04.198] [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: 10/19/2022]
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20
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Saavedra P, Brittle A, Palacios IM, Strutt D, Casal J, Lawrence PA. Planar cell polarity: the Dachsous/Fat system contributes differently to the embryonic and larval stages of Drosophila. Biol Open 2016; 5:397-408. [PMID: 26935392 PMCID: PMC4890672 DOI: 10.1242/bio.017152] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 02/01/2016] [Indexed: 11/20/2022] Open
Abstract
The epidermal patterns of all three larval instars (L1-L3) ofDrosophilaare made by one unchanging set of cells. The seven rows of cuticular denticles of all larval stages are consistently planar polarised, some pointing forwards, others backwards. In L1 all the predenticles originate at the back of the cells but, in L2 and L3, they form at the front or the back of the cell depending on the polarity of the forthcoming denticles. We find that, to polarise all rows, the Dachsous/Fat system is differentially utilised; in L1 it is active in the placement of the actin-based predenticles but is not crucial for the final orientation of the cuticular denticles, in L2 and L3 it is needed for placement and polarity. We find Four-jointed to be strongly expressed in the tendon cells and show how this might explain the orientation of all seven rows. Unexpectedly, we find that L3 that lack Dachsous differ from larvae lacking Fat and we present evidence that this is due to differently mislocalised Dachs. We make some progress in understanding how Dachs contributes to phenotypes of wildtype and mutant larvae and adults.
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Affiliation(s)
- Pedro Saavedra
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 2EJ, UK
| | - Amy Brittle
- Department of Biomedical Science, The University of Sheffield, Sheffield S10 2TN, UK
| | - Isabel M Palacios
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 2EJ, UK
| | - David Strutt
- Department of Biomedical Science, The University of Sheffield, Sheffield S10 2TN, UK
| | - José Casal
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 2EJ, UK
| | - Peter A Lawrence
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 2EJ, UK
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21
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Abstract
In multicellular organisms cells spatially arrange in a highly coordinated manner to form tissues and organs, which is essential for the function of an organism. The component cells and resulting structures are often polarised in one or more axes, and how such polarity is established and maintained correctly has been one of the major biological questions for many decades. Research progress has shown that many adhesion GPCRs (aGPCRs) are involved in several types of polarity. Members of the two evolutionarily oldest groups, Flamingo/Celsr and Latrophilins, are key molecules in planar cell polarity of epithelia or the propagation of cellular polarity in the early embryo, respectively. Other adhesion GPCRs play essential roles in cell migration, indicating that this receptor class includes essential molecules for the control of various levels of cellular organisation.
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Affiliation(s)
- David Strutt
- Bateson Centre and Department of Biomedical Science, University of Sheffield, Sheffield, UK.
| | - Ralf Schnabel
- Institute of Genetics, TU Braunschweig, Braunschweig, Germany.
| | - Franziska Fiedler
- Medical Faculty, Institute of Biochemistry, Leipzig University, Leipzig, Germany
| | - Simone Prömel
- Medical Faculty, Institute of Biochemistry, Leipzig University, Leipzig, Germany.
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22
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Affiliation(s)
- Rosalind Hale
- Bateson Centre,
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom;
| | - David Strutt
- Bateson Centre,
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom;
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23
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Strutt H, Strutt D. Planar polarity: forcing cells into line. Curr Biol 2015; 25:R1032-R1034. [PMID: 26528742 DOI: 10.1016/j.cub.2015.09.042] [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: 11/30/2022]
Abstract
Polarisation of tissues in the plane of an epithelium is fundamental for both animal morphogenesis and organ function. A new paper describes a role for mechanical cues in determining how such polarity is aligned with the body axes.
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Affiliation(s)
- Helen Strutt
- Bateson Centre and Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
| | - David Strutt
- Bateson Centre and Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
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24
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Verreault M, Wehbe M, Strutt D, Masin D, Anantha M, Walker D, Chu F, Backstrom I, Kalra J, Waterhouse D, Yapp DT, Bally MB. Determination of an optimal dosing schedule for combining Irinophore C™ and temozolomide in an orthotopic model of glioblastoma. J Control Release 2015; 220:348-357. [PMID: 26528901 DOI: 10.1016/j.jconrel.2015.10.053] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [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: 09/09/2015] [Revised: 10/22/2015] [Accepted: 10/28/2015] [Indexed: 12/30/2022]
Abstract
Our laboratory reported that Irinophore C™ (IrC™; a lipid-based nanoparticulate formulation of irinotecan) is effective against an orthotopic model of glioblastoma (GBM) and that treatment with IrC™ was associated with vascular normalization within the tumor. Here, the therapeutic effects of IrC™ when used in combination with temozolomide (TMZ) in concurrent and sequential treatment schedules were tested. It was anticipated that IrC™ engendered vascular normalization would increase the delivery of TMZ to the tumor and that this would be reflected by improved treatment outcomes. The approach compared equally efficacious doses of irinotecan (IRN; 50 mg/kg) and IrC™ (25 mg/kg) in order to determine if there was a unique advantage achieved when combining TMZ with IrC™. The TMZ sensitive U251MG(O) cell line (null expression of O-6-methylguanine-DNA methyltransferase (MGMT)) modified to express the fluorescent protein mKate2 was inoculated orthotopically into NOD.CB17-SCID mice and treatment was initiated 14 days later. Our results demonstrated that IrC™ and TMZ administered concurrently resulted in optimal treatment outcomes, with 50% long term survivors (>180 days) in comparison to 17% long term survivors in animals treated with IRN and TMZ or TMZ alone. Indeed, the different treatments resulted in a 353%, 222% and 280% increase in median survival time (MST) compared to untreated animals for, respectively, IrC™ combined with TMZ, IRN combined with TMZ, and TMZ alone. When TMZ was administered after completion of IRN or IrC™ dosing, an increase in median survival time of 167-174% was observed compared to untreated animals and of 67% and 74%, respectively, when IRN (50 mg/kg) and IrC™ (25mg/kg) were given as single agents. We confirmed in these studies that after completion of the Q7D×3 dosing of IrC™, but not IRN, the tumor-associated vascular was normalized as compared to untreated tumors. Specifically, reductions in the fraction of collagen IV-free CD31 staining (p<0.05) and reductions in tumor vessel diameter were observed in tumors from IrC™-treated animals when compared to tumors from untreated or IRN treated animals. Analysis by transmission electron microscopy of the ultra-structure of tumors from IrC™-treated and untreated animals revealed that tumor-associated vessels from treated animals were smaller, more organized and exhibited a morphology comparable to normal blood vessels. In conclusion, optimal treatment outcomes were achieved when IrC™ and TMZ were administered concurrently, whereas IrC™ followed by TMZ treatment given sequentially did not confer any therapeutic advantage.
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Affiliation(s)
- M Verreault
- Brain and Spine Institute Research Center, 47 Bd de l'Hopital, Paris, 75013, France.
| | - M Wehbe
- Experimental Therapeutics, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, V5Z 1L3, BC, Canada; Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver V6T 1Z3, BC, Canada
| | - D Strutt
- Experimental Therapeutics, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, V5Z 1L3, BC, Canada
| | - D Masin
- Experimental Therapeutics, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, V5Z 1L3, BC, Canada
| | - M Anantha
- Experimental Therapeutics, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, V5Z 1L3, BC, Canada
| | - D Walker
- Ultrastructural Imaging, UBC James Hogg Research Laboratories (iCAPTURE), Providence Heart and Lung Institute, St. Paul's Hospital, Rm 166, 1081 Burrard St, Vancouver, BC, Canada
| | - F Chu
- Ultrastructural Imaging, UBC James Hogg Research Laboratories (iCAPTURE), Providence Heart and Lung Institute, St. Paul's Hospital, Rm 166, 1081 Burrard St, Vancouver, BC, Canada
| | - I Backstrom
- Experimental Therapeutics, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, V5Z 1L3, BC, Canada
| | - J Kalra
- Experimental Therapeutics, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, V5Z 1L3, BC, Canada
| | - D Waterhouse
- Experimental Therapeutics, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, V5Z 1L3, BC, Canada
| | - D T Yapp
- Experimental Therapeutics, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, V5Z 1L3, BC, Canada; Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver V6T 1Z3, BC, Canada
| | - M B Bally
- Experimental Therapeutics, British Columbia Cancer Agency, 675 West 10th Avenue, Vancouver, V5Z 1L3, BC, Canada; Faculty of Pharmaceutical Sciences, University of British Columbia, 2146 East Mall, Vancouver V6T 1Z3, BC, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, 2211 Wesbrook Mall, Vancouver V6T 2B5, BC, Canada; Center for Drug Research and Development, Vancouver V6T 1Z4, BC, Canada.
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25
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Hale R, Brittle AL, Fisher KH, Monk NAM, Strutt D. Cellular interpretation of the long-range gradient of Four-jointed activity in the Drosophila wing. eLife 2015; 4. [PMID: 25707557 PMCID: PMC4338440 DOI: 10.7554/elife.05789] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [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: 11/27/2014] [Accepted: 02/02/2015] [Indexed: 01/23/2023] Open
Abstract
To understand how long-range patterning gradients are interpreted at the cellular level, we investigate how a gradient of expression of the Four-jointed kinase specifies planar polarised distributions of the cadherins Fat and Dachsous in the Drosophila wing. We use computational modelling to test different scenarios for how Four-jointed might act and test the model predictions by employing fluorescence recovery after photobleaching as an in vivo assay to measure the influence of Four-jointed on Fat-Dachsous binding. We demonstrate that in vivo, Four-jointed acts both on Fat to promote its binding to Dachsous and on Dachsous to inhibit its binding to Fat, with a bias towards a stronger effect on Fat. Overall, we show that opposing gradients of Fat and Dachsous phosphorylation are sufficient to explain the observed pattern of Fat–Dachsous binding and planar polarisation across the wing, and thus demonstrate the mechanism by which a long-range gradient is interpreted. DOI:http://dx.doi.org/10.7554/eLife.05789.001 Epithelial cells form sheets that line the body surfaces and internal cavities of animals—such as the skin and the lining of the gut. Certain structures on the surface of epithelial cell sheets—for example scales, hair, and feathers—are often all orientated in a particular direction. Epithelial cells with structures organised like this are described as being ‘planar polarised’. Different proteins work together to set up planar polarity in a sheet of epithelial cells. Dachsous and Fat are two proteins that are found in the cell membranes of epithelial cells, including in the wings of the fruit fly Drosophila. These proteins bind to each other and link a cell to its neighbour. Dachsous and Fat accumulate on opposing sides of each cell: Fat accumulates on the side closest to the fly's body, and Dachsous builds up on the side closest to the wing tip. This pattern provides directional cues that help orientate surface structures, and the pattern is established, in part, by the activity of an enzyme called Four-jointed. Four-jointed adds phosphate groups onto Dachsous and Fat. The activity of the Four-jointed enzyme forms a gradient along a developing wing: levels are low near the fly's body, and high at the wing tip. Previous experiments performed on cells grown in the laboratory showed that when Four-jointed adds phosphate groups to Fat and Dachsous, it prevents Dachsous from binding to Fat. However, it also makes Fat more able to bind to Dachsous. These opposing effects are thought to cause the proteins to accumulate on opposing sides of each cell. However, this has yet to be demonstrated in real tissue, not least because of the technical difficulty of measuring whether Fat-Dachsous binding has occurred in living organisms. Here, Hale et al. overcome this challenge using a method called ‘fluorescence recovery after photobleaching’ (or FRAP) to measure Fat and Dachsous binding in the epithelial cells in the developing Drosophila wing. Combining these experimental results with a computational model confirmed the findings of previous laboratory studies: that Four-jointed makes it easier for Fat to bind to Dachsous, and makes it more difficult for Dachsous to bind to Fat. The opposing effects on the activity of Fat and Dachsous that result from the Four-jointed gradient in the developing wing are able to fully explain the observed patterns of Fat-Dachsous binding and of planar polarisation across the wing. Overall, Hale et al. demonstrate how a gradient of protein activity that spans many cells is sensed and interpreted by individual cells to establish planar polarity. However, exactly how the phosphate groups added to Dachsous and Fat by Four-jointed modifies how they bind to each other remains a question for future work. DOI:http://dx.doi.org/10.7554/eLife.05789.002
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Affiliation(s)
- Rosalind Hale
- Bateson Centre, University of Sheffield, Sheffield, United Kingdom
| | - Amy L Brittle
- Bateson Centre, University of Sheffield, Sheffield, United Kingdom
| | | | - Nicholas A M Monk
- School of Mathematics and Statistics, University of Sheffield, Sheffield, United Kingdom
| | - David Strutt
- Bateson Centre, University of Sheffield, Sheffield, United Kingdom
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26
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Thomas C, Strutt D. Rabaptin-5 and Rabex-5 are neoplastic tumour suppressor genes that interact to modulate Rab5 dynamics in Drosophila melanogaster. Dev Biol 2013; 385:107-21. [PMID: 24104056 PMCID: PMC3858806 DOI: 10.1016/j.ydbio.2013.09.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [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: 08/01/2013] [Revised: 09/25/2013] [Accepted: 09/29/2013] [Indexed: 01/08/2023]
Abstract
Endocytosis plays an important role in the regulation of tumour growth and metastasis. In Drosophila, a number of endocytic neoplastic tumour suppressor genes have been identified that when mutated cause epithelial disruption and over-proliferation. Here we characterise the Drosophila homologue of the Rab5 effector Rabaptin-5, and show that it is a novel neoplastic tumour suppressor. Its ability to bind Rab5 and modulate early endosomal dynamics is conserved in Drosophila, as is its interaction with the Rab5 GEF Rabex5, for which we also demonstrate neoplastic tumour suppressor characteristics. Surprisingly, we do not observe disruption of apico-basal polarity in Rabaptin-5 and Rabex-5 mutant tissues; instead the tumour phenotype is associated with upregulation of Jun N-terminal Kinase (JNK) and Janus Kinase (JAK)/Signal Transducer and Activator of Transcription (STAT) signalling. Drosophila Rabaptin-5 and Rabex-5 are endocytic neoplastic tumour suppressor genes. The Rab5 effector function of Rabaptin-5 is highly conserved in Drosophila. Rabaptin-5 interacts with Rabex-5 to modulate early endosomal dynamics in vivo. Tumour phenotypes are associated with upregulation of JNK and JAK/STAT signalling.
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Affiliation(s)
- Chloe Thomas
- MRC Centre for Developmental and Biomedical Genetics, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
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27
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Wells RE, Barry JD, Warrington SJ, Cuhlmann S, Evans P, Huber W, Strutt D, Zeidler MP. Control of tissue morphology by Fasciclin III-mediated intercellular adhesion. Development 2013; 140:3858-68. [PMID: 23946443 PMCID: PMC3915571 DOI: 10.1242/dev.096214] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [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: 12/23/2022]
Abstract
Morphogenesis is dependent on the orchestration of multiple developmental processes to generate mature functional organs. However, the signalling pathways that coordinate morphogenesis and the mechanisms that translate these signals into tissue shape changes are not well understood. Here, we demonstrate that changes in intercellular adhesion mediated by the transmembrane protein Fasciclin III (FasIII) represent a key mediator of morphogenesis. Using the embryonic Drosophila hindgut as an in vivo model for organogenesis, we show that the tightening of hindgut curvature that normally occurs between embryonic stage 12 and 15 to generate the characteristic shepherd’s crook shape is dependent on localised JAK/STAT pathway activation. This localised pathway activity drives the expression of FasIII leading to its subcellular lateralisation at a stage before formation of septate junctions. Additionally, we show that JAK/STAT- and FasIII-dependent morphogenesis also regulates folds within the third instar wing imaginal disc. We show that FasIII forms homophilic intercellular interactions that promote intercellular adhesion in vivo and in cultured cells. To explore these findings, we have developed a mathematical model of the developing hindgut, based on the differential interfacial tension hypothesis (DITH) linking intercellular adhesion and localised surface tension. Our model suggests that increased intercellular adhesion provided by FasIII can be sufficient to drive the tightening of tube curvature observed. Taken together, these results identify a conserved molecular mechanism that directly links JAK/STAT pathway signalling to intercellular adhesion and that sculpts both tubular and planar epithelial shape.
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Affiliation(s)
- Richard E Wells
- MRC Centre for Developmental and Biomedical Genetics, The University of Sheffield, Firth Court, Sheffield S10 2TN, UK
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Strutt H, Thomas-MacArthur V, Strutt D. Strabismus promotes recruitment and degradation of farnesylated prickle in Drosophila melanogaster planar polarity specification. PLoS Genet 2013; 9:e1003654. [PMID: 23874239 PMCID: PMC3715439 DOI: 10.1371/journal.pgen.1003654] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [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: 03/26/2013] [Accepted: 06/04/2013] [Indexed: 11/19/2022] Open
Abstract
The core planar polarity proteins are required to specify the orientation of structures that are polarised in the plane of the epithelium. In the Drosophila melanogaster wing, the core proteins localise asymmetrically at either proximal or distal cell edges. Asymmetric localisation is thought to be biased by long-range cues, causing asymmetric complexes to become aligned with the tissue axes. Core proteins are then thought to participate in feedback interactions that are necessary to amplify asymmetry, and in order for such feedback interactions to operate correctly, the levels of the core proteins at junctions must be tightly regulated. We have investigated regulation of the core protein Prickle (Pk) in the pupal wing. The core protein Strabismus (Stbm) is required to recruit Pk into asymmetric complexes at proximal cell ends, and we report here that it also promotes proteasomal degradation of excess Pk, probably via a Cullin-1 dependent process. We also show for the first time that Pk is farnesylated in vivo, and this is essential for Pk function in the wing. Notably, farnesylation of Pk is necessary for it to be recruited into asymmetric complexes and function in feedback amplification, probably by reinforcing weak direct interactions between Stbm and Pk. Furthermore, farnesylation is also required for Stbm to promote proteasomal degradation of Pk. We propose that Stbm recruits farnesylated Pk into asymmetric complexes, but also promotes degradation of excess Pk that would otherwise perturb feedback amplification.
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Affiliation(s)
- Helen Strutt
- MRC Centre for Developmental and Biomedical Genetics and Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, United Kingdom
| | - Vickie Thomas-MacArthur
- MRC Centre for Developmental and Biomedical Genetics and Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, United Kingdom
| | - David Strutt
- MRC Centre for Developmental and Biomedical Genetics and Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, United Kingdom
- * E-mail:
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Abley K, De Reuille PB, Strutt D, Bangham A, Prusinkiewicz P, Marée AFM, Grieneisen VA, Coen E. An intracellular partitioning-based framework for tissue cell polarity in plants and animals. Development 2013; 140:2061-74. [PMID: 23633507 DOI: 10.1242/dev.062984] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Tissue cell polarity plays a major role in plant and animal development. We propose that a fundamental building block for tissue cell polarity is the process of intracellular partitioning, which can establish individual cell polarity in the absence of asymmetric cues. Coordination of polarities may then arise through cell-cell coupling, which can operate directly, through membrane-spanning complexes, or indirectly, through diffusible molecules. Polarity is anchored to tissues through organisers located at boundaries. We show how this intracellular partitioning-based framework can be applied to both plant and animal systems, allowing different processes to be placed in a common evolutionary and mechanistic context.
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Affiliation(s)
- Katie Abley
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
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Strutt H, Searle E, Thomas-Macarthur V, Brookfield R, Strutt D. A Cul-3-BTB ubiquitylation pathway regulates junctional levels and asymmetry of core planar polarity proteins. Development 2013; 140:1693-702. [PMID: 23487316 PMCID: PMC3621487 DOI: 10.1242/dev.089656] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The asymmetric localisation of core planar polarity proteins at apicolateral junctions is required to specify cell polarity in the plane of epithelia. This asymmetric distribution of the core proteins is proposed to require amplification of an initial asymmetry by feedback loops. In addition, generation of asymmetry appears to require the regulation of core protein levels, but the importance of such regulation and the underlying mechanisms is unknown. Here we show that ubiquitylation acts through more than one mechanism to control core protein levels in Drosophila, and that without this regulation cellular asymmetry is compromised. Levels of Dishevelled at junctions are regulated by a Cullin-3-Diablo/Kelch ubiquitin ligase complex, the activity of which is most likely controlled by neddylation. Furthermore, activity of the deubiquitylating enzyme Fat facets is required to maintain Flamingo levels at junctions. Notably, ubiquitylation does not alter the total cellular levels of Dishevelled or Flamingo, but only that of the junctional population. When junctional core protein levels are either increased or decreased by disruption of the ubiquitylation machinery, their asymmetric localisation is reduced and this leads to disruption of planar polarity at the tissue level. Loss of asymmetry by altered core protein levels can be explained by reference to feedback models for amplification of asymmetry.
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Affiliation(s)
- Helen Strutt
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
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Warrington SJ, Strutt H, Strutt D. The Frizzled-dependent planar polarity pathway locally promotes E-cadherin turnover via recruitment of RhoGEF2. J Cell Sci 2013. [DOI: 10.1242/jcs.132647] [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: 10/26/2022] Open
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Warrington SJ, Strutt H, Strutt D. The Frizzled-dependent planar polarity pathway locally promotes E-cadherin turnover via recruitment of RhoGEF2. Development 2013; 140:1045-54. [PMID: 23364328 PMCID: PMC3583042 DOI: 10.1242/dev.088724] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Polarised tissue elongation during morphogenesis involves cells within epithelial sheets or tubes making and breaking intercellular contacts in an oriented manner. Growing evidence suggests that cell adhesion can be modulated by endocytic trafficking of E-cadherin (E-cad), but how this process can be polarised within individual cells is poorly understood. The Frizzled (Fz)-dependent core planar polarity pathway is a major regulator of polarised cell rearrangements in processes such as gastrulation, and has also been implicated in regulation of cell adhesion through trafficking of E-cad; however, it is not known how these functions are integrated. We report a novel role for the core planar polarity pathway in promoting cell intercalation during tracheal tube morphogenesis in Drosophila embryogenesis, and present evidence that this is due to regulation of turnover and levels of junctional E-cad by the guanine exchange factor RhoGEF2. Furthermore, we show that core pathway activity leads to planar-polarised recruitment of RhoGEF2 and E-cad turnover in the epidermis of both the embryonic germband and the pupal wing. We thus reveal a general mechanism by which the core planar polarity pathway can promote polarised cell rearrangements.
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Affiliation(s)
- Samantha J Warrington
- MRC Centre for Developmental and Biomedical Genetics, and Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
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Brittle A, Thomas C, Strutt D. Planar polarity specification through asymmetric subcellular localization of Fat and Dachsous. Curr Biol 2012; 22:907-14. [PMID: 22503504 PMCID: PMC3362735 DOI: 10.1016/j.cub.2012.03.053] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [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: 01/24/2012] [Revised: 03/07/2012] [Accepted: 03/15/2012] [Indexed: 11/28/2022]
Abstract
Two pathways regulate planar polarity: the core proteins and the Fat-Dachsous-Four-jointed (Ft-Ds-Fj) system. Morphogens specify complementary expression patterns of Ds and Fj that potentially act as polarizing cues. It has been suggested that Ft-Ds-Fj-mediated cues are weak and that the core proteins amplify them. Another view is that the two pathways act independently to generate and propagate polarity: if correct, this raises the question of how gradients of Ft and Ds expression or activity might be interpreted to provide strong cellular polarizing cues and how such cues are propagated from cell to cell. Here, we demonstrate that the complementary expression of Ds and Fj results in biased Ft and Ds protein distribution across cells, with Ft and Ds accumulating on opposite edges. Furthermore, boundaries of Ft and Ds expression result in subcellular asymmetries in protein distribution that are transmitted to neighboring cells, and asymmetric Ds localization results in a corresponding asymmetric distribution of the myosin Dachs. We show that the generation of subcellular asymmetries of Ft and Ds and the core proteins is largely independent in the wing disc and additionally that ommatidial polarity in the eye can be determined without input from the Ft-Ds-Fj system, consistent with the two pathways acting in parallel.
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Affiliation(s)
- Amy Brittle
- MRC Centre for Developmental and Biomedical Genetics, University of Sheffield, Western Bank, Sheffield, UK
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Thomas C, Strutt D. The roles of the cadherins Fat and Dachsous in planar polarity specification in Drosophila. Dev Dyn 2011; 241:27-39. [PMID: 21919123 DOI: 10.1002/dvdy.22736] [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] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/22/2011] [Indexed: 11/06/2022] Open
Abstract
Planar polarity is generated through the activity of two groups of proteins, the "core" system and the Fat (Ft)/Dachsous (Ds) system. Although both are conserved from insects to mammals, vertebrate studies into planar polarity have primarily focussed on core planar polarity proteins and have only recently branched into the study of the Ft/Ds system. In Drosophila, however, years of detailed analysis have started to elucidate some of the mechanisms by which Ft/Ds signalling might set up polarity across a tissue, and how this may impact upon core protein-mediated planar polarity. In this review, we discuss the major findings, models, and controversies that have emerged from Drosophila research into the Ft/Ds system, and indicate some areas for further investigation.
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Affiliation(s)
- Chloe Thomas
- MRC Centre for Developmental and Biomedical Genetics and Department of Biomedical Science, University of Sheffield, Sheffield, United Kingdom.
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Verreault M, Strutt D, Masin D, Fink D, Gill R, Bally MB. Development of glioblastoma cell lines expressing red fluorescence for non-invasive live imaging of intracranial tumors. Anticancer Res 2011; 31:2161-71. [PMID: 21737636] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
UNLABELLED Glioblastoma (GBM) cell lines expressing red fluorescent proteins were evaluated as a tool for non-invasive imaging of orthotopic tumors. MATERIALS AND METHODS mKate2- and mCherry-transduced U251MG GBM lines were sorted by flow cytometry. The growth rates and drug sensitivity of the resulting cell lines were compared to those of the parental line. Following orthotopic implantation, mKate2-expressing cells were detected using multispectral imaging. RESULTS Flow cytometry-sorted fluorescent populations exhibiting growth curves that were comparable to those of the parental line were selected. mKate2-expressing cells were inoculated orthotopically and formed tumors which were visualized non-invasively, allowing monitoring of tumor growth over time and the assessment of tumor response to temozolomide drug treatment. CONCLUSION The strategy reported here led to the successful development of GBM models expressing mKate2 or mCherry. The fluorescence signal intensity measured in the brain of live animals correlates with tumor size, thus providing a method to assess tumor progression and response to treatment.
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Affiliation(s)
- M Verreault
- Experimental Therapeutics, British Columbia Cancer Agency, BCCRC, 675, W 10th avenue, Vancouver, BC, V5Z 1L3, Canada.
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Abstract
Planar polarity describes the coordinated polarisation of cells or structures in the plane of a tissue. The patterning mechanisms that underlie planar polarity are well characterised in Drosophila, where many events are regulated by two pathways: the 'core' planar polarity complex and the Fat/Dachsous system. Components of both pathways also function in vertebrates and are implicated in diverse morphogenetic processes, some of which self-evidently involve planar polarisation and some of which do not. Here, we review the molecular mechanisms and cellular consequences of planar polarisation in diverse contexts, seeking to identify the common principles across the animal kingdom.
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Affiliation(s)
- Lisa V. Goodrich
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - David Strutt
- MRC Centre for Developmental and Biomedical Genetics and Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
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37
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Strutt H, Warrington S, Strutt D. Dynamics of core planar polarity protein turnover and stable assembly into discrete membrane subdomains. Dev Cell 2011; 20:511-25. [PMID: 21497763 PMCID: PMC3094756 DOI: 10.1016/j.devcel.2011.03.018] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 03/04/2011] [Accepted: 03/25/2011] [Indexed: 11/28/2022]
Abstract
The core planar polarity proteins localize asymmetrically to the adherens junctions of epithelial cells, where they have been hypothesized to assemble into intercellular complexes. Here, we show that the core proteins are preferentially distributed to discrete membrane subdomains ("puncta"), where they form asymmetric contacts between neighboring cells. Using an antibody internalization assay and fluorescence recovery after photobleaching in prepupal and pupal wings, we have investigated the turnover of two key core proteins, Flamingo and Frizzled, and find that the localization of both within puncta is highly stable. Furthermore, the transmembrane core proteins, Flamingo, Frizzled, and Strabismus, are necessary for stable localization of core proteins to junctions, whereas the cytoplasmic core proteins are required for their concentration into puncta. Thus, we define the distinct roles of specific core proteins in the formation of asymmetric contacts between cells, which is a key event in the generation of coordinated cellular asymmetry.
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Affiliation(s)
- Helen Strutt
- MRC Centre for Developmental and Biomedical Genetics, and Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - Samantha J. Warrington
- MRC Centre for Developmental and Biomedical Genetics, and Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
| | - David Strutt
- MRC Centre for Developmental and Biomedical Genetics, and Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK
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38
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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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Brittle AL, Repiso A, Casal J, Lawrence PA, Strutt D. Four-jointed modulates growth and planar polarity by reducing the affinity of dachsous for fat. Curr Biol 2010; 20:803-10. [PMID: 20434337 PMCID: PMC2958304 DOI: 10.1016/j.cub.2010.03.056] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 02/19/2010] [Accepted: 03/02/2010] [Indexed: 12/31/2022]
Abstract
The Drosophila genes fat (ft) and dachsous (ds) encode large atypical cadherins that collaborate to coordinately polarize cells in the plane of the epithelium (planar cell polarity) and to affect growth via the Warts/Hippo pathway. Ft and Ds form heterodimeric bridges that convey polarity information from cell to cell. four-jointed (fj) is a modulator of Ft/Ds activity that acts in a graded fashion in the abdomen, eye, and wing. Genetic evidence indicates that Fj acts via Ds and/or Ft, and here we demonstrate that Fj can act independently on Ds and on Ft. It has been reported that Fj has kinase activity and can phosphorylate a subset of cadherin domains of both Ft and Ds in vitro. We have used both cell and in vitro assays to measure binding between Ft and Ds. We find that phosphorylation of Ds reduces its affinity for Ft in both of these assays. By expressing forms of Ds that lack the defined phosphorylation sites or have phosphomimetic amino acids at these positions, we demonstrate that effects of Fj on wing size and planar polarity can be explained by Fj phosphorylating these sites.
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Affiliation(s)
- Amy L Brittle
- Medical Research Council (MRC) Centre for Developmental and Biomedical Genetics and Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK
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Abstract
In addition to specifying cell fate, there is a wealth of evidence that molecular gradients are also primarily responsible for specifying cell polarity, particularly in the plane of epithelial sheets ("planar polarity"). The first compelling evidence of a role for gradients in specifying planar polarity came from transplantation experiments in the insect cuticle. More recent molecular genetic analyses in the fruit fly Drosophila have begun to give insights into the molecular nature of the gradients involved, and how they are interpreted at the cellular level.
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Affiliation(s)
- David Strutt
- MRC Centre for Developmental and Biomedical Genetics and Department of Biomedical Science, University of Sheffield, United Kingdom.
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Wells R, Strutt D, Zeidler M. 09-P088 Examination of cell signalling involved in the convergent extension movements during Drosophila embryonic hindgut development. Mech Dev 2009. [DOI: 10.1016/j.mod.2009.06.418] [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: 10/20/2022]
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Warrington S, Strutt D. 03-P047 The planar polarity pathway and trachea formation in the Drosophila embryo. Mech Dev 2009. [DOI: 10.1016/j.mod.2009.06.100] [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: 11/27/2022]
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Brown S, Smythe E, Strutt D, Whitworth A, Zeidler M. 18-P019 The University of Sheffield RNAi Screening facility: Genome-wide RNAi screens in Drosophila cells using a 2nd generation in silico optimized library. Mech Dev 2009. [DOI: 10.1016/j.mod.2009.06.786] [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: 10/20/2022]
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Searle E, Strutt H, Strutt D. 08-P002 Characterisation of the role of ubiquitin-like molecules in regulating sub-cellular trafficking of core planar polarity proteins in the Drosophila wing. Mech Dev 2009. [DOI: 10.1016/j.mod.2009.06.309] [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: 10/20/2022]
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Strutt H, Strutt D. Asymmetric localisation of planar polarity proteins: Mechanisms and consequences. Semin Cell Dev Biol 2009; 20:957-63. [PMID: 19751618 DOI: 10.1016/j.semcdb.2009.03.006] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Revised: 03/02/2009] [Accepted: 03/12/2009] [Indexed: 01/30/2023]
Abstract
Planar polarisation of tissues is essential for many aspects of developmental patterning. It is regulated by a conserved group of core planar polarity proteins, which localise asymmetrically within cells prior to morphological signs of polarisation. A subset of these core proteins also interact across cell boundaries, mediating intercellular communication that co-ordinates polarity between neighbouring cells. Core protein localisation subsequently mediates changes in the actin cytoskeleton which lead to overt polarisation. In this review we discuss the mechanisms by which the core planar polarity proteins become asymmetrically localised, and the significance of this subcellular localisation for both intercellular communication and downstream effects on the cytoskeleton.
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Affiliation(s)
- Helen Strutt
- MRC Centre for Developmental and Biomedical Genetics and Department of Biomedical Science, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK.
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Strutt H, Strutt D. Differential stability of flamingo protein complexes underlies the establishment of planar polarity. Curr Biol 2008; 18:1555-64. [PMID: 18804371 PMCID: PMC2593845 DOI: 10.1016/j.cub.2008.08.063] [Citation(s) in RCA: 122] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 08/01/2008] [Accepted: 08/28/2008] [Indexed: 12/20/2022]
Abstract
BACKGROUND The planar polarization of developing tissues is controlled by a conserved set of core planar polarity proteins. In the Drosophila pupal wing, these proteins adopt distinct proximal and distal localizations in apicolateral junctions that act as subcellular polarity cues to control morphological events. The core polarity protein Flamingo (Fmi) localizes to both proximal and distal cell boundaries and is known to have asymmetric activity, but the molecular basis of this asymmetric activity is unknown. RESULTS We examine the role of Fmi in controlling asymmetric localization of polarity proteins in pupal wing cells. We find that Fmi interacts preferentially with distal-complex components, rather than with proximal components, and present evidence that there are different domain requirements for Fmi to associate with distal and proximal components. We further show that distally and proximally localized proteins cooperate to allow stable accumulation of Fmi at apicolateral junctions and present evidence that the rates of endocytic trafficking of Fmi are increased when Fmi is not in a stable asymmetric complex. Finally, we provide evidence that Fmi is trafficked from junctions via both Dishevelled-dependent and Dishevelled-independent mechanisms. CONCLUSIONS We present a model in which the primary function of Fmi is to participate in the formation of inherently stable asymmetric junctional complexes: Removal from junctions of Fmi that is not in stable complexes, combined with directional trafficking of Frizzled and Fmi to the distal cell edge, drives the establishment of cellular asymmetry.
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Affiliation(s)
- Helen Strutt
- MRC Centre for Developmental and Biomedical Genetics and, Department of Biomedical Science, University of Sheffield, Western Bank, S10 2TN Sheffield, United Kingdom
| | - David Strutt
- MRC Centre for Developmental and Biomedical Genetics and, Department of Biomedical Science, University of Sheffield, Western Bank, S10 2TN Sheffield, United Kingdom
- Corresponding author
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Strutt D, Warrington SJ. Planar polarity genes in the Drosophila wing regulate the localisation of the FH3-domain protein Multiple Wing Hairs to control the site of hair production. Development 2008; 135:3103-11. [PMID: 18701542 DOI: 10.1242/dev.025205] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The core planar polarity proteins play important roles in coordinating cell polarity, in part by adopting asymmetric subcellular localisations that are likely to serve as cues for cell polarisation by as yet uncharacterised pathways. Here we describe the role of Multiple Wing Hairs (Mwh), a novel formin homology 3 (FH3)-domain protein, which acts downstream of the core polarity proteins to restrict the production of actin-rich prehairs to distal cell edges in the Drosophila pupal wing. Mwh appears to function as a repressor of actin filament formation and, in its absence, ectopic actin bundles are seen across the entire apical surface of cells. We show that the proximally localised core polarity protein Strabismus acts via the downstream effector proteins Inturned, Fuzzy and Fritz to stabilise Mwh in apico-proximal cellular regions. In addition, the distally localised core polarity protein Frizzled positively promotes prehair initiation, suggesting that both proximal and distal cellular cues act together to ensure accurate prehair placement.
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Affiliation(s)
- David Strutt
- MRC Centre for Developmental and Biomedical Genetics and Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield S10 2TN, UK.
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Brunk K, Vernay B, Griffith E, Reynolds NL, Strutt D, Ingham PW, Jackson AP. Microcephalin coordinates mitosis in the syncytialDrosophilaembryo. J Cell Sci 2007; 120:3578-88. [PMID: 17895363 DOI: 10.1242/jcs.014290] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [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: 12/15/2022] Open
Abstract
Microcephalin (MCPH1) is mutated in primary microcephaly, an autosomal recessive human disorder of reduced brain size. It encodes a protein with three BRCT domains that has established roles in DNA damage signalling and the cell cycle, regulating chromosome condensation. Significant adaptive evolutionary changes in primate MCPH1 sequence suggest that changes in this gene could have contributed to the evolution of the human brain. To understand the developmental role of microcephalin we have studied its function in Drosophila. We report here that Drosophila MCPH1 is cyclically localised during the cell cycle, co-localising with DNA during interphase, but not with mitotic chromosomes. mcph1 mutant flies have a maternal effect lethal phenotype, due to mitotic arrest occurring in early syncytial cell cycles. Mitotic entry is slowed from the very first mitosis in such embryos, with prolonged prophase and metaphase stages; and frequent premature separation as well as detachment of centrosomes. As a consequence, centrosome and nuclear cycles become uncoordinated, resulting in arrested embryonic development. Phenotypic similarities with abnormal spindle (asp) and centrosomin (cnn) mutants (whose human orthologues are also mutated in primary microcephaly), suggest that further studies in the Drosophila embryo may establish a common developmental and cellular pathway underlying the human primary microcephaly phenotype.
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Affiliation(s)
- Kathrin Brunk
- Institute of Integrative and Comparative Biology, University of Leeds, LS2 9JT, UK
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Abstract
Cell migration is fundamental in both animal morphogenesis and disease. The migration of individual cells is relatively well-studied; however, in vivo, cells often remain joined by cell-cell junctions and migrate in cohesive groups. How such groups of cells coordinate their migration is poorly understood. The planar polarity pathway coordinates the polarity of non-migrating cells in epithelial sheets and is required for cell rearrangements during vertebrate morphogenesis. It is therefore a good candidate to play a role in the collective migration of groups of cells. Drosophila border cell migration is a well-characterised and genetically tractable model of collective cell migration, during which a group of about six to ten epithelial cells detaches from the anterior end of the developing egg chamber and migrates invasively towards the oocyte. We find that the planar polarity pathway promotes this invasive migration, acting both in the migrating cells themselves and in the non-migratory polar follicle cells that they carry along. Disruption of planar polarity signalling causes abnormalities in actin-rich processes on the cell surface and leads to less-efficient migration. This is apparently due, in part, to a loss of regulation of Rho GTPase activity by the planar polarity receptor Frizzled, which itself becomes localised to the migratory edge of the border cells. We conclude that, during collective cell migration, the planar polarity pathway can mediate communication between motile and non-motile cells, which enhances the efficiency of migration via the modulation of actin dynamics.
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Affiliation(s)
| | - David Strutt
- Corresponding author, , Tel. +44 114 222 2372, Fax. +44 114 276 5413
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Strutt D, Strutt H. Differential activities of the core planar polarity proteins during Drosophila wing patterning. Dev Biol 2006; 302:181-94. [PMID: 17045581 PMCID: PMC2082130 DOI: 10.1016/j.ydbio.2006.09.026] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2006] [Revised: 09/11/2006] [Accepted: 09/11/2006] [Indexed: 11/21/2022]
Abstract
During planar polarity patterning of the Drosophila wing, a “core” group of planar polarity genes has been identified which acts downstream of global polarity cues to locally coordinate cell polarity and specify trichome production at distal cell edges. These genes encode protein products that assemble into asymmetric apicolateral complexes that straddle the proximodistal junctional region between adjacent cells. We have carried out detailed genetic analysis experiments, analysing the requirements of each complex component for planar polarity patterning. We find that the three transmembrane proteins at the core of the complex, Frizzled, Strabismus and Flamingo, are required earliest in development and are the only components needed for intercellular polarity signalling. Notably, cells that lack both Frizzled and Strabismus are unable to signal, revealing an absolute requirement for both proteins in cell–cell communication. In contrast the cytoplasmic components Dishevelled, Prickle and Diego are not needed for intercellular communication. These factors contribute to the cell–cell propagation of polarity, most likely by promotion of intracellular asymmetry. Interestingly, both local polarity propagation and trichome placement occur normally in mutant backgrounds where asymmetry of polarity protein distribution is undetectable, suggesting such asymmetry is not an absolute requirement for any of the functions of the core complex.
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Affiliation(s)
- David Strutt
- Centre for Developmental and Biomedical Genetics, Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, UK.
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