1
|
Yost PP, Al-Nouman A, Curtiss J. The Rap1 small GTPase affects cell fate or survival and morphogenetic patterning during Drosophila melanogaster eye development. Differentiation 2023; 133:12-24. [PMID: 37437447 PMCID: PMC10528170 DOI: 10.1016/j.diff.2023.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 07/14/2023]
Abstract
The Drosophila melanogaster eye has been instrumental for determining both how cells communicate with one another to determine cell fate, as well as cell morphogenesis and patterning. Here, we describe the effects of the small GTPase Rap1 on the development of multiple cell types in the D. melanogaster eye. Although Rap1 has previously been linked to RTK-Ras-MAPK signaling in eye development, we demonstrate that manipulation of Rap1 activity is modified by increase or decrease of Delta/Notch signaling during several events of cell fate specification in eye development. In addition, we demonstrate that manipulating Rap1 function either in primary pigment cells or in interommatidial cells affects cone cell contact switching, primary pigment cell enwrapment of the ommatidial cluster, and sorting of secondary and tertiary pigment cells. These data suggest that Rap1 has roles in both ommatidial cell recruitment/survival and in ommatidial morphogenesis in the pupal stage. They lay groundwork for future experiments on the role of Rap1 in these events.
Collapse
Affiliation(s)
- Philip P Yost
- New Mexico State University, 1780 E University Ave, Las Cruces, NM, 88003, USA
| | | | - Jennifer Curtiss
- New Mexico State University, 1780 E University Ave, Las Cruces, NM, 88003, USA.
| |
Collapse
|
2
|
Vuong LT, Mlodzik M. Different strategies by distinct Wnt-signaling pathways in activating a nuclear transcriptional response. Curr Top Dev Biol 2022; 149:59-89. [PMID: 35606062 PMCID: PMC9870056 DOI: 10.1016/bs.ctdb.2022.02.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The Wnt family of secreted glycolipo-proteins signals through multiple signal transduction pathways and is essential for embryonic development and organ development and homeostasis. The Wnt-pathways are conserved and critical in all metazoans. Wnt signaling pathways comprise the canonical Wnt/β-catenin pathway and several non-canonical signaling branches, of which Wnt-Planar Cell Polarity (PCP) signaling and the Wnt/Calcium pathway have received the most attention and are best understood. nterestingly, all Wnt-pathways have a nuclear signaling branch and also can affect many cellular processes independent of its nuclear transcriptional regulation. Canonical Wnt/β-catenin signaling is the most critical for a nuclear transcriptional response, in both development and disease, yet the mechanism(s) on how the "business end" of the pathway, β-catenin, translocates to the nucleus to act as co-activator to the TCF/Lef transcription factor family still remains obscure. Here we discuss and compare the very different strategies on how the respective Wnt signaling pathways activate a nuclear transcriptional response. We also highlight some recent new insights into how β-catenin is translocated to the nucleus via an IFT-A, Kinesin-2, and microtubule dependent mechanism and how this aspect of canonical Wnt-signaling uses ciliary proteins in a cilium independent manner, conserved between Drosophila and mammalian cells.
Collapse
Affiliation(s)
| | - Marek Mlodzik
- Department of Cell, Developmental, & Regenerative Biology, Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States.
| |
Collapse
|
3
|
Abstract
The molecular complexes underlying planar cell polarity (PCP) were first identified in Drosophila through analysis of mutant phenotypes in the adult cuticle and the orientation of associated polarized protrusions such as wing hairs and sensory bristles. The same molecules are conserved in vertebrates and are required for the localization of polarized protrusions such as primary or sensory cilia and the orientation of hair follicles. Not only is PCP signaling required to align cellular structures across a tissue, it is also required to coordinate movement during embryonic development and adult homeostasis. PCP signaling allows cells to interpret positional cues within a tissue to move in the appropriate direction and to coordinate this movement with their neighbors. In this review we outline the molecular basis of the core Wnt-Frizzled/PCP pathway, and describe how this signaling orchestrates collective motility in Drosophila and vertebrates. Here we cover the paradigms of ommatidial rotation and border cell migration in Drosophila, and convergent extension in vertebrates. The downstream cell biological processes that underlie polarized motility include cytoskeletal reorganization, and adherens junctional and extracellular matrix remodeling. We discuss the contributions of these processes in the respective cell motility contexts. Finally, we address examples of individual cell motility guided by PCP factors during nervous system development and in cancer disease contexts.
Collapse
|
4
|
Piedade WP, Famulski JK. E3 ubiquitin ligase-mediated regulation of vertebrate ocular development; new insights into the function of SIAH enzymes. Biochem Soc Trans 2021; 49:327-340. [PMID: 33616626 PMCID: PMC7924998 DOI: 10.1042/bst20200613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/22/2021] [Accepted: 01/25/2021] [Indexed: 01/18/2023]
Abstract
Developmental regulation of the vertebrate visual system has been a focus of investigation for generations as understanding this critical time period has direct implications on our understanding of congenital blinding disease. The majority of studies to date have focused on transcriptional regulation mediated by morphogen gradients and signaling pathways. However, recent studies of post translational regulation during ocular development have shed light on the role of the ubiquitin proteasome system (UPS). This rather ubiquitous yet highly diverse system is well known for regulating protein function and localization as well as stability via targeting for degradation by the 26S proteasome. Work from many model organisms has recently identified UPS activity during various milestones of ocular development including retinal morphogenesis, retinal ganglion cell function as well as photoreceptor homeostasis. In particular work from flies and zebrafish has highlighted the role of the E3 ligase enzyme family, Seven in Absentia Homologue (Siah) during these events. In this review, we summarize the current understanding of UPS activity during Drosophila and vertebrate ocular development, with a major focus on recent findings correlating Siah E3 ligase activity with two major developmental stages of vertebrate ocular development, retinal morphogenesis and photoreceptor specification and survival.
Collapse
|
5
|
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] [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.
Collapse
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
| |
Collapse
|
6
|
Koca Y, Housden BE, Gault WJ, Bray SJ, Mlodzik M. Notch signaling coordinates ommatidial rotation in the Drosophila eye via transcriptional regulation of the EGF-Receptor ligand Argos. Sci Rep 2019; 9:18628. [PMID: 31819141 PMCID: PMC6901570 DOI: 10.1038/s41598-019-55203-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Accepted: 11/24/2019] [Indexed: 02/02/2023] Open
Abstract
In all metazoans, a small number of evolutionarily conserved signaling pathways are reiteratively used during development to orchestrate critical patterning and morphogenetic processes. Among these, Notch (N) signaling is essential for most aspects of tissue patterning where it mediates the communication between adjacent cells to control cell fate specification. In Drosophila, Notch signaling is required for several features of eye development, including the R3/R4 cell fate choice and R7 specification. Here we show that hypomorphic alleles of Notch, belonging to the Nfacet class, reveal a novel phenotype: while photoreceptor specification in the mutant ommatidia is largely normal, defects are observed in ommatidial rotation (OR), a planar cell polarity (PCP)-mediated cell motility process. We demonstrate that during OR Notch signaling is specifically required in the R4 photoreceptor to upregulate the transcription of argos (aos), an inhibitory ligand to the epidermal growth factor receptor (EGFR), to fine-tune the activity of EGFR signaling. Consistently, the loss-of-function defects of Nfacet alleles and EGFR-signaling pathway mutants are largely indistinguishable. A Notch-regulated aos enhancer confers R4 specific expression arguing that aos is directly regulated by Notch signaling in this context via Su(H)-Mam-dependent transcription.
Collapse
Affiliation(s)
- Yildiz Koca
- 0000 0001 0670 2351grid.59734.3cDept. of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029 USA ,0000 0001 0670 2351grid.59734.3cGraduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029 USA
| | - Benjamin E. Housden
- 0000000121885934grid.5335.0Dept. of Physiology, Development and Neuroscience, University of Cambridge Downing Street, Cambridge, CB2 3DY UK ,0000 0004 1936 8024grid.8391.3Present Address: Living Systems Institute, University of Exeter, Exeter, EX4 4QD UK
| | - William J. Gault
- 0000 0001 0670 2351grid.59734.3cDept. of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029 USA ,0000 0001 0670 2351grid.59734.3cGraduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029 USA ,0000 0001 2264 7145grid.254250.4Present Address: City College of New York, 160 Convert Ave, New York, NY USA
| | - Sarah J. Bray
- 0000000121885934grid.5335.0Dept. of Physiology, Development and Neuroscience, University of Cambridge Downing Street, Cambridge, CB2 3DY UK
| | - Marek Mlodzik
- 0000 0001 0670 2351grid.59734.3cDept. of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029 USA ,0000 0001 0670 2351grid.59734.3cGraduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029 USA
| |
Collapse
|
7
|
Domingos PM, Jenny A, Combie KF, Del Alamo D, Mlodzik M, Steller H, Mollereau B. Regulation of Numb during planar cell polarity establishment in the Drosophila eye. Mech Dev 2019; 160:103583. [PMID: 31678471 DOI: 10.1016/j.mod.2019.103583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 10/17/2019] [Accepted: 10/29/2019] [Indexed: 01/15/2023]
Abstract
The establishment of planar cell polarity (PCP) in the Drosophila eye requires correct specification of the R3/R4 pair of photoreceptor cells, determined by a Frizzled mediated signaling event that specifies R3 and induces Delta to activate Notch signaling in the neighboring cell, specifying it as R4. Here, we investigated the role of the Notch signaling negative regulator Numb in the specification of R3/R4 fates and PCP establishment in the Drosophila eye. We observed that Numb is transiently upregulated in R3 at the time of R3/R4 specification. This regulation of Numb levels in developing photoreceptors occurs at the post-transcriptional level and is dependent on Dishevelled, an effector of Frizzled signaling, and Lethal Giant Larva. We detected PCP defects in cells homozygous for numb15, but these defects were due to a loss of function mutation in fat (fatQ805⁎) being present in the numb15 chromosome. However, mosaic overexpression of Numb in R4 precursors (only) caused PCP defects and numb loss-of-function alleles had a modifying effect on the defects found in a hypomorphic dishevelled mutation. Our results suggest that Numb levels are upregulated to reinforce the bias of Notch signaling activation in the R3/R4 pair, two post-mitotic cells that are not specified by asymmetric cell division.
Collapse
Affiliation(s)
- Pedro M Domingos
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, Oeiras 2780-157, Portugal; Strang Laboratory of Apoptosis and Cancer Research, The Rockefeller University, Box 252, 1230 York Avenue, New York, NY 10065, USA.
| | - Andreas Jenny
- Albert Einstein College of Medicine, 1300 Morris Park Avenue, Chanin Building, Room 503, Bronx NY10461, USA; Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA
| | - Keon F Combie
- Strang Laboratory of Apoptosis and Cancer Research, The Rockefeller University, Box 252, 1230 York Avenue, New York, NY 10065, USA
| | - David Del Alamo
- Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA; European Molecular Biology Organization, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Marek Mlodzik
- Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA
| | - Hermann Steller
- Strang Laboratory of Apoptosis and Cancer Research, The Rockefeller University, Box 252, 1230 York Avenue, New York, NY 10065, USA
| | - Bertrand Mollereau
- Strang Laboratory of Apoptosis and Cancer Research, The Rockefeller University, Box 252, 1230 York Avenue, New York, NY 10065, USA; Université de Lyon, ENSL, UCBL, CNRS, LBMC, 46 Allée d'Italie, 69007 Lyon, France.
| |
Collapse
|
8
|
Bala Tannan N, Collu G, Humphries AC, Serysheva E, Weber U, Mlodzik M. AKAP200 promotes Notch stability by protecting it from Cbl/lysosome-mediated degradation in Drosophila melanogaster. PLoS Genet 2018; 14:e1007153. [PMID: 29309414 PMCID: PMC5785023 DOI: 10.1371/journal.pgen.1007153] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 01/25/2018] [Accepted: 12/13/2017] [Indexed: 12/30/2022] Open
Abstract
AKAP200 is a Drosophila melanogaster member of the “A Kinase Associated Protein” family of scaffolding proteins, known for their role in the spatial and temporal regulation of Protein Kinase A (PKA) in multiple signaling contexts. Here, we demonstrate an unexpected function of AKAP200 in promoting Notch protein stability. In Drosophila, AKAP200 loss-of-function (LOF) mutants show phenotypes that resemble Notch LOF defects, including eye patterning and sensory organ specification defects. Through genetic interactions, we demonstrate that AKAP200 interacts positively with Notch in both the eye and the thorax. We further show that AKAP200 is part of a physical complex with Notch. Biochemical studies reveal that AKAP200 stabilizes endogenous Notch protein, and that it limits ubiquitination of Notch. Specifically, our genetic and biochemical evidence indicates that AKAP200 protects Notch from the E3-ubiquitin ligase Cbl, which targets Notch to the lysosomal pathway. Indeed, we demonstrate that the effect of AKAP200 on Notch levels depends on the lysosome. Interestingly, this function of AKAP200 is fully independent of its role in PKA signaling and independent of its ability to bind PKA. Taken together, our data indicate that AKAP200 is a novel tissue specific posttranslational regulator of Notch, maintaining high Notch protein levels and thus promoting Notch signaling. AKAP200 belongs to a family of scaffolding proteins best known for their regulation of PKA localization. In this study, we have identified a novel role of AKAP200 in Notch protein stability and signaling. In Drosophila melanogaster, AKAP200’s loss and gain-of-function (LOF/GOF) phenotypes are characteristic of Notch signaling defects. Furthermore, we demonstrated genetic interactions between AKAP200 and Notch. Consistent with this, AKAP200 stabilizes the endogenous Notch protein and limits its ubiquitination. AKAP200 exerts its effects on Notch by antagonizing Cbl-mediated ubiquitination and thus lysosome targeting of Notch. Based on these data, we postulate a novel PKA independent mechanism of AKAP200 to achieve optimal Notch protein levels, with AKAP200 preventing Cbl-mediated lysosomal degradation of Notch.
Collapse
Affiliation(s)
- Neeta Bala Tannan
- Dept. of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Giovanna Collu
- Dept. of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Ashley C. Humphries
- Dept. of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Ekatherina Serysheva
- Dept. of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Ursula Weber
- Dept. of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
| | - Marek Mlodzik
- Dept. of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, New York, United States of America
- * E-mail:
| |
Collapse
|
9
|
Perez-Mockus G, Schweisguth F. Cell Polarity and Notch Signaling: Linked by the E3 Ubiquitin Ligase Neuralized? Bioessays 2017; 39. [DOI: 10.1002/bies.201700128] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 08/17/2017] [Indexed: 12/19/2022]
Affiliation(s)
- Gantas Perez-Mockus
- Institut Pasteur,; Dept of Developmental and Stem Cell Biology; F-75015 Paris France
- CNRS; UMR3738; F-75015 Paris France
- Univ. Pierre et Marie Curie; Cellule Pasteur UPMC; rue du Dr Roux 75015 Paris France
| | - Francois Schweisguth
- Institut Pasteur,; Dept of Developmental and Stem Cell Biology; F-75015 Paris France
- CNRS; UMR3738; F-75015 Paris France
| |
Collapse
|
10
|
Perez-Mockus G, Roca V, Mazouni K, Schweisguth F. Neuralized regulates Crumbs endocytosis and epithelium morphogenesis via specific Stardust isoforms. J Cell Biol 2017; 216:1405-1420. [PMID: 28400441 PMCID: PMC5412571 DOI: 10.1083/jcb.201611196] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 02/13/2017] [Accepted: 02/23/2017] [Indexed: 11/22/2022] Open
Abstract
The E3 ubiquitin ligase Neuralized is shown to interact with a subset of the Stardust isoforms to regulate the endocytosis of the apical protein Crumbs and thereby promote epithelial remodeling during Drosophila development. Crumbs (Crb) is a conserved determinant of apical membrane identity that regulates epithelial morphogenesis in many developmental contexts. In this study, we identify the Crb complex protein Stardust (Sdt) as a target of the E3 ubiquitin ligase Neuralized (Neur) in Drosophila melanogaster. Neur interacts with and down-regulates specific Sdt isoforms containing a Neur binding motif (NBM). Using a CRISPR (clustered regularly interspaced short palindromic repeats)-induced deletion of the NBM-encoding exon, we found that Sdt is a key Neur target and that Neur acts via Sdt to down-regulate Crb. We further show that Neur promotes the endocytosis of Crb via the NBM-containing isoforms of Sdt. Although the regulation of Crb by Neur is not strictly essential, it contributes to epithelium remodeling in the posterior midgut and thereby facilitates the trans-epithelial migration of the primordial germ cells in early embryos. Thus, our study uncovers a novel regulatory mechanism for the developmental control of Crb-mediated morphogenesis.
Collapse
Affiliation(s)
- Gantas Perez-Mockus
- Department of Developmental and Stem Cell Biology, Institut Pasteur, F-75015 Paris, France.,Centre National de la Recherché Scientifique, UMR3738, F-75015 Paris, France.,Cellule Pasteur, Université Pierre et Marie Curie, F-75015 Paris, France
| | - Vanessa Roca
- Department of Developmental and Stem Cell Biology, Institut Pasteur, F-75015 Paris, France.,Centre National de la Recherché Scientifique, UMR3738, F-75015 Paris, France
| | - Khalil Mazouni
- Department of Developmental and Stem Cell Biology, Institut Pasteur, F-75015 Paris, France.,Centre National de la Recherché Scientifique, UMR3738, F-75015 Paris, France
| | - François Schweisguth
- Department of Developmental and Stem Cell Biology, Institut Pasteur, F-75015 Paris, France .,Centre National de la Recherché Scientifique, UMR3738, F-75015 Paris, France
| |
Collapse
|
11
|
Devenport D. Tissue morphodynamics: Translating planar polarity cues into polarized cell behaviors. Semin Cell Dev Biol 2016; 55:99-110. [PMID: 26994528 DOI: 10.1016/j.semcdb.2016.03.012] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 03/15/2016] [Indexed: 12/21/2022]
Abstract
The ability of cells to collectively orient and align their behaviors is essential in multicellular organisms for unidirectional cilia beating, collective cell movements, oriented cell divisions, and asymmetric cell fate specification. The planar cell polarity pathway coordinates a vast and diverse array of collective cell behaviors by intersecting with downstream pathways that regulate cytoskeletal dynamics and intercellular signaling. How the planar polarity pathway translates directional cues to produce polarized cell behaviors is the focus of this review.
Collapse
Affiliation(s)
- Danelle Devenport
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA.
| |
Collapse
|
12
|
Muñoz-Soriano V, Santos D, Durupt FC, Casani S, Paricio N. Scabrous overexpression in the eye affects R3/R4 cell fate specification and inhibits notch signaling. Dev Dyn 2015; 245:166-74. [PMID: 26505171 DOI: 10.1002/dvdy.24362] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 10/07/2015] [Accepted: 10/23/2015] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Planar cell polarity (PCP) in the Drosophila eye is generated when immature ommatidial preclusters acquire opposite chirality in the dorsal and ventral halves of the eye imaginal disc and rotate 90 ° toward the equator. The scabrous (sca) gene is involved in R8 differentiation and in the correct spacing of ommatidial clusters in eye imaginal discs, but it was also suggested to be required during ommatidial rotation. However, no clear relationships between sca and other genes involved in the process were established. RESULTS To explore the role of Sca in PCP establishment, we performed an RNAi-based modifier genetic screen using the rough eye phenotype of sca-overexpressing flies. We found that sca overexpression mainly affects R3/R4 cell specification as it was reported in Notch mutants. Of the 86 modifiers identified in the screen, genes encoding components of Notch signaling and proteins involved in intracellular transport were of particular interest. CONCLUSIONS These and other results obtained with a reporter line of Notch activity indicate that sca overexpression antagonizes Notch signaling in the Drosophila eye, and are inconsistent with Sca being an ommatidial rotation-specific factor. We also found that microtubule motors and other proteins involved in intracellular transport are related with Sca function.
Collapse
Affiliation(s)
- Verónica Muñoz-Soriano
- Departamento de Genética, Facultad CC Biológicas, Universidad de Valencia, Burjasot, Spain.,Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, Burjasot, Spain
| | - Diego Santos
- Departamento de Genética, Facultad CC Biológicas, Universidad de Valencia, Burjasot, Spain
| | - Fabrice C Durupt
- Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, Burjasot, Spain
| | - Sandra Casani
- Departamento de Genética, Facultad CC Biológicas, Universidad de Valencia, Burjasot, Spain
| | - Nuria Paricio
- Departamento de Genética, Facultad CC Biológicas, Universidad de Valencia, Burjasot, Spain.,Estructura de Recerca Interdisciplinar en Biotecnologia i Biomedicina (ERI BIOTECMED), Universidad de Valencia, Burjasot, Spain
| |
Collapse
|
13
|
Collu GM, Hidalgo-Sastre A, Brennan K. Wnt-Notch signalling crosstalk in development and disease. Cell Mol Life Sci 2014; 71:3553-67. [PMID: 24942883 PMCID: PMC11113451 DOI: 10.1007/s00018-014-1644-x] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 04/17/2014] [Accepted: 05/05/2014] [Indexed: 10/25/2022]
Abstract
The Notch and Wnt pathways are two of only a handful of highly conserved signalling pathways that control cell-fate decisions during animal development (Pires-daSilva and Sommer in Nat Rev Genet 4: 39-49, 2003). These two pathways are required together to regulate many aspects of metazoan development, ranging from germ layer patterning in sea urchins (Peter and Davidson in Nature 474: 635-639, 2011) to the formation and patterning of the fly wing (Axelrod et al in Science 271:1826-1832, 1996; Micchelli et al in Development 124:1485-1495, 1997; Rulifson et al in Nature 384:72-74, 1996), the spacing of the ciliated cells in the epidermis of frog embryos (Collu et al in Development 139:4405-4415, 2012) and the maintenance and turnover of the skin, gut lining and mammary gland in mammals (Clayton et al in Nature 446:185-189, 2007; Clevers in Cell 154:274-284, 2013; Doupe et al in Dev Cell 18:317-323, 2010; Lim et al in Science 342:1226-1230, 2013; Lowell et al in Curr Biol 10:491-500, 2000; van et al in Nature 435:959-963, 2005; Yin et al in Nat Methods 11:106-112, 2013). In addition, many diseases, including several cancers, are caused by aberrant signalling through the two pathways (Bolós et al in Endocr Rev 28: 339-363, 2007; Clevers in Cell 127: 469-480, 2006). In this review, we will outline the two signalling pathways, describe the different points of interaction between them, and cover how these interactions influence development and disease.
Collapse
Affiliation(s)
- Giovanna M Collu
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, M13 9PT, UK,
| | | | | |
Collapse
|
14
|
Singh J, Mlodzik M. Planar cell polarity signaling: coordination of cellular orientation across tissues. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2014; 1:479-99. [PMID: 23066429 DOI: 10.1002/wdev.32] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Establishment of Planar Cell Polarity (PCP) in epithelia, in the plane of an epithelium, is an important feature of the development and homeostasis of most organs. Studies in different model organisms have contributed a wealth of information regarding the mechanisms that govern PCP regulation. Genetic studies in Drosophila have identified two signaling systems, the Fz/PCP and Fat/Dachsous system, which are both required for PCP establishment in many different tissues in a largely non-redundant manner. Recent advances in vertebrate PCP studies have added novel factors of PCP regulation and also new cellular features requiring PCP-signaling input, including the positioning and orientation of the primary cilium of many epithelial cells. This review focuses mostly on several recent advances made in the Drosophila and vertebrate PCP field and integrates these within the existing PCP-signaling framework.
Collapse
Affiliation(s)
- Jaskirat Singh
- Department of Developmental & Regenerative Biology, Mount Sinai School of Medicine, New York, NY, USA
| | | |
Collapse
|
15
|
Cortijo C, Gouzi M, Tissir F, Grapin-Botton A. Planar cell polarity controls pancreatic beta cell differentiation and glucose homeostasis. Cell Rep 2012. [PMID: 23177622 DOI: 10.1016/j.celrep.2012.10.016] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Planar cell polarity (PCP) refers to the collective orientation of cells within the epithelial plane. We show that progenitor cells forming the ducts of the embryonic pancreas express PCP proteins and exhibit an active PCP pathway. Planar polarity proteins are acquired at embryonic day 11.5 synchronously to apicobasal polarization of pancreas progenitors. Loss of function of the two PCP core components Celsr2 and Celsr3 shows that they control the differentiation of endocrine cells from polarized progenitors, with a prevalent effect on insulin-producing beta cells. This results in a decreased glucose clearance. Loss of Celsr2 and 3 leads to a reduction of Jun phosphorylation in progenitors, which, in turn, reduces beta cell differentiation from endocrine progenitors. These results highlight the importance of the PCP pathway in cell differentiation in vertebrates. In addition, they reveal that tridimensional organization and collective communication of cells are needed in the pancreatic epithelium in order to generate appropriate numbers of endocrine cells.
Collapse
Affiliation(s)
- Cedric Cortijo
- Swiss Institute for Experimental Cancer Research, Life Sciences, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | | | | | | |
Collapse
|
16
|
Patel MV, Hallal DA, Jones JW, Bronner DN, Zein R, Caravas J, Husain Z, Friedrich M, Vanberkum MFA. Dramatic expansion and developmental expression diversification of the methuselah gene family during recent Drosophila evolution. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2012; 318:368-87. [PMID: 22711569 DOI: 10.1002/jez.b.22453] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Functional studies of the methuselah/methuselah-like (mth/mthl) gene family have focused on the founding member mth, but little is known regarding the developmental functions of this receptor or any of its paralogs. We undertook a comprehensive analysis of developmental expression and sequence divergence in the mth/mthl gene family. Using in situ hybridization techniques, we detect expression of six genes (mthl1, 5, 9, 11, 13, and 14) in the embryo during gastrulation and development of the gut, heart, and lymph glands. Four receptors (mthl3, 4, 6, and 8) are expressed in the larval central nervous system, imaginal discs, or both, and two receptors (mthl10 and mth) are expressed in both embryos and larvae. Phylogenetic analysis of all mth/mthl genes in five Drosophila species, mosquito and flour beetle structured the mth/mthl family into several subclades. mthl1, 5, and 14 are present in most species, each forming a separate clade. A newly identified Drosophila mthl gene (CG31720; herein mthl15) formed another ancient clade. The remaining Drosophila receptors, including mth, are members of a large "superclade" that diversified relatively recently during dipteran evolution, in many cases within the melanogaster subgroup. Comparing the expression patterns of the mth/mthl "superclade" paralogs to the embryonic expression of the singleton ortholog in Tribolium suggests both subfunctionalization and acquisition of novel functionalities. Taken together, our findings shed novel light on mth as a young member of an adaptively evolving developmental gene family.
Collapse
Affiliation(s)
- Meghna V Patel
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Singh J, Mlodzik M. Hibris, a Drosophila nephrin homolog, is required for presenilin-mediated Notch and APP-like cleavages. Dev Cell 2012; 23:82-96. [PMID: 22814602 DOI: 10.1016/j.devcel.2012.04.021] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Revised: 03/13/2012] [Accepted: 04/30/2012] [Indexed: 01/12/2023]
Abstract
Drosophila Hibris (Hbs), a member of the Nephrin Immunoglobulin Super Family, has been implicated in myogenesis and eye patterning. Here, we uncover a role of Hbs in Notch (N) signaling and γ-secretase processing. Loss of hbs results in classical N-signaling-associated phenotypes in Drosophila, including eye patterning, wing margin, and sensory organ specification defects. In particular, hbs mutant larvae display altered γ-secretase-dependent Notch proteolytic processing. Hbs also interacts molecularly and genetically with Presenilin (Psn) and other components of the γ-secretase complex. This Hbs function appears conserved, as mammalian Nephrin also promotes N signaling in mammalian cells. Our data suggest that Hbs is required for Psn maturation. Consistent with its role in Psn processing, Hbs genetically interacts with the Drosophila β-amyloid protein precursor-like (Appl) protein, the homolog of mammalian APP, the cleavage of which is associated with Alzheimer's disease. Thus, Hbs/Nephrin appear to share a general requirement in Psn/γ-secretase regulation and associated processes.
Collapse
Affiliation(s)
- Jaskirat Singh
- Department of Developmental & Regenerative Biology, Mount Sinai School of Medicine and Graduate School of Biological Sciences, One Gustave L. Levy Place, New York, NY 10029, USA
| | | |
Collapse
|
18
|
Capilla A, Johnson R, Daniels M, Benavente M, Bray SJ, Galindo MI. Planar cell polarity controls directional Notch signaling in the Drosophila leg. Development 2012; 139:2584-93. [PMID: 22736244 DOI: 10.1242/dev.077446] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The generation of functional structures during development requires tight spatial regulation of signaling pathways. Thus, in Drosophila legs, in which Notch pathway activity is required to specify joints, only cells distal to ligand-producing cells are capable of responding. Here, we show that the asymmetric distribution of planar cell polarity (PCP) proteins correlates with this spatial restriction of Notch activation. Frizzled and Dishevelled are enriched at distal sides of each cell and hence localize at the interface with ligand-expressing cells in the non-responding cells. Elimination of PCP gene function in cells proximal to ligand-expressing cells is sufficient to alleviate the repression, resulting in ectopic Notch activity and ectopic joint formation. Mutations that compromise a direct interaction between Dishevelled and Notch reduce the efficacy of repression. Likewise, increased Rab5 levels or dominant-negative Deltex can suppress the ectopic joints. Together, these results suggest that PCP coordinates the spatial activity of the Notch pathway by regulating endocytic trafficking of the receptor.
Collapse
Affiliation(s)
- Amalia Capilla
- Developmental Cell Biology Unit, Instituto de Biomedicina de Valencia, Valencia, Spain
| | | | | | | | | | | |
Collapse
|
19
|
Shang F, Taylor A. Roles for the ubiquitin-proteasome pathway in protein quality control and signaling in the retina: implications in the pathogenesis of age-related macular degeneration. Mol Aspects Med 2012; 33:446-66. [PMID: 22521794 PMCID: PMC3417153 DOI: 10.1016/j.mam.2012.04.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 04/05/2012] [Indexed: 10/28/2022]
Abstract
The accumulation of damaged or postsynthetically modified proteins and dysregulation of inflammatory responses and angiogenesis in the retina/RPE are thought be etiologically related to formation of drusen and choroidal neovascularization (CNV), hallmarks of age-related macular degeneration (AMD). The ubiquitin-proteasome pathway (UPP) plays crucial roles in protein quality control, cell cycle control and signal transduction. Selective degradation of aberrant proteins by the UPP is essential for timely removal of potentially cytotoxic damaged or otherwise abnormal proteins. Proper function of the UPP is thought to be required for cellular function. In contrast, age--or stress induced--impairment the UPP or insufficient UPP capacity may contribute to the accumulation of abnormal proteins, cytotoxicity in the retina, and AMD. Crucial roles for the UPP in eye development, regulation of signal transduction, and antioxidant responses are also established. Insufficient UPP capacity in retina and RPE can result in dysregulation of signal transduction, abnormal inflammatory responses and CNV. There are also interactions between the UPP and lysosomal proteolytic pathways (LPPs). Means that modulate the proteolytic capacity are making their way into new generation of pharmacotherapies for delaying age-related diseases and may augment the benefits of adequate nutrition, with regard to diminishing the burden of AMD.
Collapse
Affiliation(s)
- Fu Shang
- Laboratory for Nutrition and Vision Research, USDA Human Nutrition Research Center on Aging, Boston, MA 02111, USA.
| | | |
Collapse
|
20
|
Cho B, Fischer JA. Ral inhibits ligand-independent Notch signaling in Drosophila. Small GTPases 2012; 3:186-91. [PMID: 22750761 DOI: 10.4161/sgtp.19802] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We discovered recently that the Drosophila Ral GTPase regulates Notch signaling and thereby affects cell patterning in the eye. Although Ral functions in the ligand signaling cells, Ral does not stimulate ligand signaling directly. Rather, in cells that express both Notch receptor and ligand, Ral activity promotes a cell to become the signaler by inhibiting Notch receptor activation in that cell. Moreover, Ral inhibits a particular pathway of Notch activation-receptor activation that occurs independent of ligand binding. In this Commentary, we discuss the phenomenon of ligand-independent Notch receptor activation and how this event might be regulated by Ral.
Collapse
Affiliation(s)
- Bomsoo Cho
- Section of Molecular Cell and Developmental Biology, Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, TX, USA
| | | |
Collapse
|
21
|
Abstract
Drosophila has been the key model system for studies on planar cell polarity (PCP). The rich morphology of the insect exoskeleton contains many structures that display PCP. Among these are the trichomes (cuticular hairs) that cover much of the exoskeleton, sensory bristles, and ommatidia. Many genes have been identified that must function for the development of normal PCP. Among these are the genes that comprise the frizzled/starry night (fz/stan) and dachsous/fat pathways. The mechanisms that underlie the function of the fz/stan pathway are best understood. All of the protein products of these genes accumulate asymmetrically in wing cells and there is good evidence that this involves local intercellular signaling between protein complexes on the distal edge of one cell and the juxtaposed proximal edge of its neighbor. It is thought that a feedback system, directed transport, and stabilizing protein-protein interactions mediate the formation of distal and proximal protein complexes. These complexes appear to recruit downstream proteins that function to spatially restrict the activation of the cytoskeleton in wing cells. This leads to the formation of the array of distally pointing hairs found on wings.
Collapse
Affiliation(s)
- Paul N Adler
- Biology Department, University of Virginia, Charlottesville, Virginia, USA.
| |
Collapse
|
22
|
Shang F, Taylor A. Role of the ubiquitin-proteasome in protein quality control and signaling: implication in the pathogenesis of eye diseases. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 109:347-96. [PMID: 22727427 DOI: 10.1016/b978-0-12-397863-9.00010-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The ubiquitin-proteasome pathway (UPP) plays important roles in many cellular functions, such as protein quality control, cell cycle control, and signal transduction. The selective degradation of aberrant proteins by the UPP is essential for the timely removal of potential cytotoxic damaged or otherwise abnormal proteins. Conversely, accumulation of the cytotoxic abnormal proteins in eye tissues is etiologically associated with many age-related eye diseases such as retina degeneration, cataract, and certain types of glaucoma. Age- or stress-induced impairment or overburdening of the UPP appears to contribute to the accumulation of abnormal proteins in eye tissues. Cell cycle and signal transduction are regulated by the conditional UPP-dependent degradation of the regulators of these processes. Impairment or overburdening of the UPP could also result in dysregulation of cell cycle control and signal transduction. The consequences of the improper cell cycle and signal transduction include defects in ocular development, wound healing, angiogenesis, or inflammatory responses. Methods that enhance or preserve UPP function or reduce its burden may be useful strategies for preventing age-related eye diseases.
Collapse
Affiliation(s)
- Fu Shang
- Laboratory for Nutrition and Vision Research, USDA Human Nutrition Research Center on Aging, Boston, Massachusetts, USA
| | | |
Collapse
|
23
|
Abstract
In the first volume of Developmental Cell, it was reported that the classic Drosophila neurogenic gene neuralized encodes a ubiquitin ligase that monoubiquitylates the Notch ligand Delta, thus promoting Delta endocytosis. A requirement for ligand internalization by the signal-sending cell, although counterintuitive, remains to date a feature unique to Notch signaling. Ten years and many ubiquitin ligases later, we discuss sequels to these three papers with an eye toward reviewing the development of ideas for how ligand ubiquitylation and endocytosis propel Notch signaling.
Collapse
|
24
|
Dworkin S, Jane SM, Darido C. The planar cell polarity pathway in vertebrate epidermal development, homeostasis and repair. Organogenesis 2011; 7:202-8. [PMID: 22041517 DOI: 10.4161/org.7.3.18431] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The planar cell polarity (PCP) pathway plays a critical role in diverse developmental processes that require coordinated cellular movement, including neural tube closure and renal tubulogenesis. Recent studies have demonstrated that this pathway also has emerging relevance to the epidermis, as PCP signaling underpins many aspects of skin biology and pathology, including epidermal development, hair orientation, stem cell division and cancer. Coordinated cellular movement required for epidermal repair in mammals is also regulated by PCP signaling, and in this context, a new PCP gene encoding the developmental transcription factor Grainyhead-like 3 (Grhl3) is critical. This review focuses on the role that PCP signaling plays in the skin across a variety of epidermal functions and highlights perturbations that induce epidermal pathologies.
Collapse
Affiliation(s)
- Sebastian Dworkin
- Alfred Hospital and Monash University Central Clinical School, Prahran, VIC, Australia
| | | | | |
Collapse
|
25
|
Cho B, Fischer JA. Ral GTPase promotes asymmetric Notch activation in the Drosophila eye in response to Frizzled/PCP signaling by repressing ligand-independent receptor activation. Development 2011; 138:1349-59. [PMID: 21350007 DOI: 10.1242/dev.056002] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Ral is a small Ras-like GTPase that regulates membrane trafficking and signaling. Here, we show that in response to planar cell polarity (PCP) signals, Ral modulates asymmetric Notch signaling in the Drosophila eye. Specification of the initially equivalent R3/R4 photoreceptor precursor cells in each developing ommatidium occurs in response to a gradient of Frizzled (Fz) signaling. The cell with the most Fz signal (R3) activates the Notch receptor in the adjacent cell (R4) via the ligand Delta, resulting in R3/R4 cell determination and their asymmetric positions within the ommatidium. Two mechanisms have been proposed for ensuring that the cell with the most Fz activation sends the Delta signal: Fz-dependent transcriptional upregulation in R3 of genes that promote Delta signaling, and direct blockage of Notch receptor activation in R3 by localization of an activated Fz/Disheveled protein complex to the side of the plasma membrane adjacent to R4. Here, we discover a distinct mechanism for biasing the direction of Notch signaling that depends on Ral. Using genetic experiments in vivo, we show that, in direct response to Fz signaling, Ral transcription is upregulated in R3, and Ral represses ligand-independent activation of Notch in R3. Thus, prevention of ligand-independent Notch activation is not simply a constitutive process, but is a target for regulation by Ral during cell fate specification and pattern formation.
Collapse
Affiliation(s)
- Bomsoo Cho
- Section of Molecular Cell and Developmental Biology, Institute for Cell and Molecular Biology, The University of Texas at Austin, 1 University Station A4800, Austin, TX 78712, USA
| | | |
Collapse
|
26
|
Fujimura L, Watanabe-Takano H, Sato Y, Tokuhisa T, Hatano M. Prickle promotes neurite outgrowth via the Dishevelled dependent pathway in C1300 cells. Neurosci Lett 2009; 467:6-10. [DOI: 10.1016/j.neulet.2009.09.050] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2009] [Revised: 09/23/2009] [Accepted: 09/24/2009] [Indexed: 10/20/2022]
|
27
|
Cau E, Blader P. Notch activity in the nervous system: to switch or not switch? Neural Dev 2009; 4:36. [PMID: 19799767 PMCID: PMC2761386 DOI: 10.1186/1749-8104-4-36] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Accepted: 10/02/2009] [Indexed: 12/23/2022] Open
Abstract
The Notch pathway is instrumental for cell fate diversification during development. Pioneer studies conducted in Drosophila and more recent work performed in vertebrates have shown that in the nervous system, Notch is reiteratively employed when cells choose between two alternative fates, a process referred to as a binary fate decision. While the early (neural versus epidermal) fate decisions mainly involve an inhibitory effect of Notch on the neural fate, late fate decisions (choice between different subtypes of neural cells) have been proposed to involve a binary switch activity whereby Notch would be instructive for one fate and inhibitory for the other. We re-examine this binary switch model in light of two recent findings made in the vertebrate nervous system. First, in the zebrafish epiphysis, Notch is required to resolve a mixed identity through the inhibition of one specific fate. Second, in the murine telencephalon, Notch regulates the competence of neural progenitors to respond to the JAK/STAT pathway, thereby allowing for the induction of an astrocyte fate. In neither case is Notch instructive for the alternative fate, but rather cooperates with another signalling pathway to coordinate binary fate choices. We also review current knowledge on the molecular cascades acting downstream of Notch in the context of neural subtype diversification, a crucial issue if one is to determine Notch function as an instructive, permissive or inhibitory signal in the various cellular contexts where it is implicated. Finally, we speculate as to how such a 'non-switch' activity could contribute to the expansion of neuronal subtype diversity.
Collapse
Affiliation(s)
- Elise Cau
- Université de Toulouse, UPS, Centre de Biologie du Développement (CBD), 118 route de Narbonne, F-31062 Toulouse, France.
| | | |
Collapse
|
28
|
Le Grand F, Jones AE, Seale V, Scimè A, Rudnicki MA. Wnt7a activates the planar cell polarity pathway to drive the symmetric expansion of satellite stem cells. Cell Stem Cell 2009; 4:535-47. [PMID: 19497282 DOI: 10.1016/j.stem.2009.03.013] [Citation(s) in RCA: 353] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Revised: 02/12/2009] [Accepted: 03/19/2009] [Indexed: 12/18/2022]
Abstract
Satellite cells in skeletal muscle are a heterogeneous population of stem cells and committed progenitors. We found that quiescent satellite stem cells expressed the Wnt receptor Fzd7 and that its candidate ligand Wnt7a was upregulated during regeneration. Wnt7a markedly stimulated the symmetric expansion of satellite stem cells but did not affect the growth or differentiation of myoblasts. Silencing of Fzd7 abrogated Wnt7a binding and stimulation of stem cell expansion. Wnt7a signaling induced the polarized distribution of the planar cell polarity effector Vangl2. Silencing of Vangl2 inhibited Wnt7a action on satellite stem cell expansion. Wnt7a overexpression enhanced muscle regeneration and increased both satellite cell numbers and the proportion of satellite stem cells. Muscle lacking Wnt7a exhibited a marked decrease in satellite cell number following regeneration. Therefore, Wnt7a signaling through the planar cell polarity pathway controls the homeostatic level of satellite stem cells and hence regulates the regenerative potential of muscle.
Collapse
Affiliation(s)
- Fabien Le Grand
- Sprott Center for Stem Cell Research, Ottawa Hospital Research Institute, Regenerative Medicine Program, 501 Smyth Road, Ottawa, ON K1H 8L6, Canada
| | | | | | | | | |
Collapse
|
29
|
Shalaby NA, Parks AL, Morreale EJ, Osswalt MC, Pfau KM, Pierce EL, Muskavitch MAT. A screen for modifiers of notch signaling uncovers Amun, a protein with a critical role in sensory organ development. Genetics 2009; 182:1061-76. [PMID: 19448274 PMCID: PMC2728848 DOI: 10.1534/genetics.108.099986] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2009] [Accepted: 05/11/2009] [Indexed: 12/14/2022] Open
Abstract
Notch signaling is an evolutionarily conserved pathway essential for many cell fate specification events during metazoan development. We conducted a large-scale transposon-based screen in the developing Drosophila eye to identify genes involved in Notch signaling. We screened 10,447 transposon lines from the Exelixis collection for modifiers of cell fate alterations caused by overexpression of the Notch ligand Delta and identified 170 distinct modifier lines that may affect up to 274 genes. These include genes known to function in Notch signaling, as well as a large group of characterized and uncharacterized genes that have not been implicated in Notch pathway function. We further analyze a gene that we have named Amun and show that it encodes a protein that localizes to the nucleus and contains a putative DNA glycosylase domain. Genetic and molecular analyses of Amun show that altered levels of Amun function interfere with cell fate specification during eye and sensory organ development. Overexpression of Amun decreases expression of the proneural transcription factor Achaete, and sensory organ loss caused by Amun overexpression can be rescued by coexpression of Achaete. Taken together, our data suggest that Amun acts as a transcriptional regulator that can affect cell fate specification by controlling Achaete levels.
Collapse
Affiliation(s)
- Nevine A Shalaby
- Biology Department, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | | | | | | | | | | | | |
Collapse
|
30
|
Miller AC, Lyons EL, Herman TG. cis-Inhibition of Notch by endogenous Delta biases the outcome of lateral inhibition. Curr Biol 2009; 19:1378-83. [PMID: 19631544 DOI: 10.1016/j.cub.2009.06.042] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Revised: 05/26/2009] [Accepted: 06/18/2009] [Indexed: 01/17/2023]
Abstract
Lateral inhibition mediated by Delta/Notch (Dl/N) signaling is used throughout development to limit the number of initially equivalent cells that adopt a particular fate. Although adjacent cells express both Dl ligand and N receptor, signaling between them ultimately occurs in only one direction. Classically, this has been explained entirely by feedback: activated N can downregulate Dl, amplifying even slight asymmetries in the Dl or N activities of adjacent cells. Here, however, we present an example of lateral inhibition in which unidirectional signaling depends instead on Dl's ability to inhibit N within the same cell, a phenomenon known as cis-inhibition. By genetically manipulating individual R1/R6/R7 photoreceptor precursors in the Drosophila eye, we show that loss of Dl-mediated cis-inhibition reverses the direction of lateral signaling. Based on our finding that Dl in R1/R6s requires endocytosis to trans-activate but not to cis-inhibit N, we reexamine previously published data from other examples of lateral inhibition. We conclude that cis-inhibition generally influences the direction of Dl/N signaling and should therefore be included in standard models of lateral inhibition.
Collapse
Affiliation(s)
- Adam C Miller
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | | | | |
Collapse
|
31
|
Bartel DP, Nakamura I, Roberts LR, Scimè A, Rudnicki MA. MicroRNAs: target recognition and regulatory functions. Cell 2009. [PMID: 23403079 DOI: 10.1016/j] [Citation(s) in RCA: 463] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
MicroRNAs (miRNAs) are endogenous approximately 23 nt RNAs that play important gene-regulatory roles in animals and plants by pairing to the mRNAs of protein-coding genes to direct their posttranscriptional repression. This review outlines the current understanding of miRNA target recognition in animals and discusses the widespread impact of miRNAs on both the expression and evolution of protein-coding genes.
Collapse
Affiliation(s)
- David P Bartel
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | | | | | | | | |
Collapse
|
32
|
Alamo DD, Mlodzik M. Self-modulation of Notch signaling during ommatidial development via the Roughened eye transcriptional repressor. Development 2008; 135:2895-904. [PMID: 18653560 PMCID: PMC3270377 DOI: 10.1242/dev.022194] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Notch (N) signaling pathway is involved in a vast number of patterning processes in all metazoans. The regulation of the core N pathway is largely understood, but little is known about fine-tuning modulatory effects. Here, we address the role of Drosophila Krüppel-family Zn-finger transcription factor roughened eye (roe) in the context of N signaling. We demonstrate that during eye patterning, N signaling regulates the expression of roe. In turn, Roe negatively modulates the expression of target genes of N-signaling activation. In the absence of roe function, expression of N target genes is elevated and the resulting phenotypes during patterning of the retina are similar to those of N gain-of-function scenarios. Importantly, our data show that Roe binds regulatory DNA sequences of N target genes of the E(spl)-complex both in vitro and in vivo, independently of Su(H)-DNA interaction. Thus, our data suggest that Roe acts as a transcriptional repressor in a negative-feedback loop of the N pathway.
Collapse
|
33
|
Modeling polarity buildup and cell fate decision in the fly eye: insight into the connection between the PCP and Notch pathways. Dev Genes Evol 2008; 218:413-26. [DOI: 10.1007/s00427-008-0235-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2007] [Accepted: 06/10/2008] [Indexed: 01/28/2023]
|
34
|
Weber U, Pataki C, Mihaly J, Mlodzik M. Combinatorial signaling by the Frizzled/PCP and Egfr pathways during planar cell polarity establishment in the Drosophila eye. Dev Biol 2008; 316:110-23. [PMID: 18291359 DOI: 10.1016/j.ydbio.2008.01.016] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Revised: 01/09/2008] [Accepted: 01/10/2008] [Indexed: 12/23/2022]
Abstract
Frizzled (Fz)/PCP signaling regulates planar, vectorial orientation of cells or groups of cells within whole tissues. Although Fz/PCP signaling has been analyzed in several contexts, little is known about nuclear events acting downstream of Fz/PCP signaling in the R3/R4 cell fate decision in the Drosophila eye or in other contexts. Here we demonstrate a specific requirement for Egfr-signaling and the transcription factors Fos (AP-1), Yan and Pnt in PCP dependent R3/R4 specification. Loss and gain-of-function assays suggest that the transcription factors integrate input from Fz/PCP and Egfr-signaling and that the ETS factors Pnt and Yan cooperate with Fos (and Jun) in the PCP-specific R3/R4 determination. Our data indicate that Fos (either downstream of Fz/PCP signaling or parallel to it) and Yan are required in R3 to specify its fate (Fos) or inhibit R4 fate (Yan) and that Egfr-signaling is required in R4 via Pnt for its fate specification. Taken together with previous work establishing a Notch-dependent Su(H) function in R4, we conclude that Fos, Yan, Pnt, and Su(H) integrate Egfr, Fz, and Notch signaling input in R3 or R4 to establish cell fate and ommatidial polarity.
Collapse
Affiliation(s)
- Ursula Weber
- Department of Developmental and Regenerative Biology, Mt. Sinai School of Medicine, Annenberg Bldg. 18-92, One Gustave L. Levy Place, New York, NY 10029, USA
| | | | | | | |
Collapse
|