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Vázquez-Ulloa E, Lin KL, Lizano M, Sahlgren C. Reversible and bidirectional signaling of notch ligands. Crit Rev Biochem Mol Biol 2022; 57:377-398. [PMID: 36048510 DOI: 10.1080/10409238.2022.2113029] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The Notch signaling pathway is a direct cell-cell communication system involved in a wide variety of biological processes, and its disruption is observed in several pathologies. The pathway is comprised of a ligand-expressing (sender) cell and a receptor-expressing (receiver) cell. The canonical ligands are members of the Delta/Serrate/Lag-1 (DSL) family of proteins. Their binding to a Notch receptor in a neighboring cell induces a conformational change in the receptor, which will undergo regulated intramembrane proteolysis (RIP), liberating the Notch intracellular domain (NICD). The NICD is translocated to the nucleus and promotes gene transcription. It has been demonstrated that the ligands can also undergo RIP and nuclear translocation, suggesting a function for the ligands in the sender cell and possible bidirectionality of the Notch pathway. Although the complete mechanism of ligand processing is not entirely understood, and its dependence on Notch receptors has not been ruled out. Also, ligands have autonomous functions beyond Notch activation. Here we review the concepts of reverse and bidirectional signalization of DSL proteins and discuss the characteristics that make them more than just ligands of the Notch pathway.
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Affiliation(s)
- Elenaé Vázquez-Ulloa
- Faculty of Science and Engineering/Cell Biology, Åbo Akademi University, Turku, Finland.,Turku Bioscience, University of Turku and Åbo Akademi University, Turku, Finland
| | - Kai-Lan Lin
- Faculty of Science and Engineering/Cell Biology, Åbo Akademi University, Turku, Finland.,Turku Bioscience, University of Turku and Åbo Akademi University, Turku, Finland
| | - Marcela Lizano
- Unidad de Investigación Biomédica en Cáncer, Instituto Nacional de Cancerología- Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico.,Departamento de Medicina Genomica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, Mexico
| | - Cecilia Sahlgren
- Faculty of Science and Engineering/Cell Biology, Åbo Akademi University, Turku, Finland.,Turku Bioscience, University of Turku and Åbo Akademi University, Turku, Finland.,Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.,Institute for Complex Molecular Systems, Eindhoven University of Technology, Eindhoven, The Netherlands
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2
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Schuster-Gossler K, Boldt K, Bornhorst D, Delany-Heiken P, Ueffing M, Gossler A. Activity of the mouse Notch ligand DLL1 is sensitive to C-terminal tagging in vivo. BMC Res Notes 2021; 14:383. [PMID: 34583743 PMCID: PMC8477538 DOI: 10.1186/s13104-021-05785-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 09/14/2021] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE The mammalian Notch ligand DLL1 has essential functions during development. To visualise DLL1 in tissues, for sorting and enrichment of DLL1-expressing cells, and to efficiently purify DLL1 protein complexes we tagged DLL1 in mice with AcGFPHA or Strep/FLAG. RESULTS We generated constructs to express DLL1 that carried C-terminal in-frame an AcGFPHA tag flanked by loxP sites followed by a Strep/FLAG (SF) tag out of frame. Cre-mediated recombination replaced AcGFP-HA by SF. The AcGFPHAstopSF cassette was added to DLL1 for tests in cultured cells and introduced into endogenous DLL1 in mice by homologous recombination. Tagged DLL1 protein was detected by antibodies against GFP and HA or Flag, respectively, both in CHO cells and embryo lysates. In CHO cells the AcGFP fluorophore fused to DLL1 was functional. In vivo AcGFP expression was below the level of detection by direct fluorescence. However, the SF tag allowed us to specifically purify DLL1 complexes from embryo lysates. Homozygous mice expressing AcGFPHA or SF-tagged DLL1 revealed a vertebral column phenotype reminiscent of disturbances in AP polarity during somitogenesis, a process most sensitive to reduced DLL1 function. Thus, even small C-terminal tags can impinge on sensitive developmental processes requiring DLL1 activity.
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Affiliation(s)
- Karin Schuster-Gossler
- Institute for Molecular Biology, OE5250, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Karsten Boldt
- Institute of Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Elfriede-Aulhorn-Strasse 7, 72076, Tübingen, Germany
| | - Dorothee Bornhorst
- Institute for Molecular Biology, OE5250, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.,Institute of Biochemistry and Biology, Potsdam University, 14476, Potsdam, Germany.,Stem Cell Program and Division of Hematology/Oncology, Boston Children's Hospital, Boston, USA.,Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, USA
| | - Patricia Delany-Heiken
- Institute for Molecular Biology, OE5250, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Marius Ueffing
- Institute of Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Elfriede-Aulhorn-Strasse 7, 72076, Tübingen, Germany
| | - Achim Gossler
- Institute for Molecular Biology, OE5250, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
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3
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Kotelevets L, Chastre E. A New Story of the Three Magi: Scaffolding Proteins and lncRNA Suppressors of Cancer. Cancers (Basel) 2021; 13:4264. [PMID: 34503076 PMCID: PMC8428372 DOI: 10.3390/cancers13174264] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 08/17/2021] [Accepted: 08/20/2021] [Indexed: 12/16/2022] Open
Abstract
Scaffolding molecules exert a critical role in orchestrating cellular response through the spatiotemporal assembly of effector proteins as signalosomes. By increasing the efficiency and selectivity of intracellular signaling, these molecules can exert (anti/pro)oncogenic activities. As an archetype of scaffolding proteins with tumor suppressor property, the present review focuses on MAGI1, 2, and 3 (membrane-associated guanylate kinase inverted), a subgroup of the MAGUK protein family, that mediate networks involving receptors, junctional complexes, signaling molecules, and the cytoskeleton. MAGI1, 2, and 3 are comprised of 6 PDZ domains, 2 WW domains, and 1 GUK domain. These 9 protein binding modules allow selective interactions with a wide range of effectors, including the PTEN tumor suppressor, the β-catenin and YAP1 proto-oncogenes, and the regulation of the PI3K/AKT, the Wnt, and the Hippo signaling pathways. The frequent downmodulation of MAGIs in various human malignancies makes these scaffolding molecules and their ligands putative therapeutic targets. Interestingly, MAGI1 and MAGI2 genetic loci generate a series of long non-coding RNAs that act as a tumor promoter or suppressor in a tissue-dependent manner, by selectively sponging some miRNAs or by regulating epigenetic processes. Here, we discuss the different paths followed by the three MAGIs to control carcinogenesis.
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Affiliation(s)
- Larissa Kotelevets
- Sorbonne Université, INSERM, UMR_S938, Centre de Recherche Saint-Antoine (CRSA), 75012 Paris, France
| | - Eric Chastre
- Sorbonne Université, INSERM, UMR_S938, Centre de Recherche Saint-Antoine (CRSA), 75012 Paris, France
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4
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Rubey M, Chhabra NF, Gradinger D, Sanz-Moreno A, Lickert H, Przemeck GKH, Hrabě de Angelis M. DLL1- and DLL4-Mediated Notch Signaling Is Essential for Adult Pancreatic Islet Homeostasis. Diabetes 2020; 69:915-926. [PMID: 32029480 DOI: 10.2337/db19-0795] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 01/22/2020] [Indexed: 11/13/2022]
Abstract
Genes of the Notch signaling pathway are expressed in different cell types and organs at different time points during embryonic development and adulthood. The Notch ligand Delta-like 1 (DLL1) controls the decision between endocrine and exocrine fates of multipotent progenitors in the developing pancreas, and loss of Dll1 leads to premature endocrine differentiation. However, the role of Delta-Notch signaling in adult tissue homeostasis is not well understood. Here, we describe the spatial expression pattern of Notch pathway components in adult murine pancreatic islets and show that DLL1 and DLL4 are specifically expressed in β-cells, whereas JAGGED1 is expressed in α-cells. We show that mice lacking both DLL1 and DLL4 in adult β-cells display improved glucose tolerance, increased glucose-stimulated insulin secretion, and hyperglucagonemia. In contrast, overexpression of the intracellular domain of DLL1 in adult murine pancreatic β-cells results in impaired glucose tolerance and reduced insulin secretion, both in vitro and in vivo. These results suggest that Notch ligands play specific roles in the adult pancreas and highlight a novel function of the Delta/Notch pathway in β-cell insulin secretion.
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Affiliation(s)
- Marina Rubey
- Institute of Experimental Genetics and German Mouse Clinic, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research, Neuherberg, Germany
| | - Nirav Florian Chhabra
- Institute of Experimental Genetics and German Mouse Clinic, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research, Neuherberg, Germany
| | - Daniel Gradinger
- Institute of Experimental Genetics and German Mouse Clinic, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research, Neuherberg, Germany
| | - Adrián Sanz-Moreno
- Institute of Experimental Genetics and German Mouse Clinic, Helmholtz Zentrum München, Neuherberg, Germany
| | - Heiko Lickert
- German Center for Diabetes Research, Neuherberg, Germany
- Institute of Diabetes and Regeneration Research and Institute of Stem Cell Research, Helmholtz Zentrum München, Neuherberg, Germany
- Medical Faculty, Technische Universität München, Munich, Germany
| | - Gerhard K H Przemeck
- Institute of Experimental Genetics and German Mouse Clinic, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research, Neuherberg, Germany
| | - Martin Hrabě de Angelis
- Institute of Experimental Genetics and German Mouse Clinic, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research, Neuherberg, Germany
- Centre of Life and Food Sciences, Weihenstephan, Technische Universität München, Freising, Germany
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5
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Tetzlaff F, Adam MG, Feldner A, Moll I, Menuchin A, Rodriguez-Vita J, Sprinzak D, Fischer A. MPDZ promotes DLL4-induced Notch signaling during angiogenesis. eLife 2018; 7:e32860. [PMID: 29620522 PMCID: PMC5933922 DOI: 10.7554/elife.32860] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 04/04/2018] [Indexed: 12/18/2022] Open
Abstract
Angiogenesis is coordinated by VEGF and Notch signaling. DLL4-induced Notch signaling inhibits tip cell formation and vessel branching. To ensure proper Notch signaling, receptors and ligands are clustered at adherens junctions. However, little is known about factors that control Notch activity by influencing the cellular localization of Notch ligands. Here, we show that the multiple PDZ domain protein (MPDZ) enhances Notch signaling activity. MPDZ physically interacts with the intracellular carboxyterminus of DLL1 and DLL4 and enables their interaction with the adherens junction protein Nectin-2. Inactivation of the MPDZ gene leads to impaired Notch signaling activity and increased blood vessel sprouting in cellular models and the embryonic mouse hindbrain. Tumor angiogenesis was enhanced upon endothelial-specific inactivation of MPDZ leading to an excessively branched and poorly functional vessel network resulting in tumor hypoxia. As such, we identified MPDZ as a novel modulator of Notch signaling by controlling ligand recruitment to adherens junctions.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Animals
- Calcium-Binding Proteins
- Carcinoma, Lewis Lung/blood supply
- Carcinoma, Lewis Lung/metabolism
- Carcinoma, Lewis Lung/pathology
- Carrier Proteins/physiology
- Cells, Cultured
- Human Umbilical Vein Endothelial Cells
- Humans
- Intercellular Signaling Peptides and Proteins/genetics
- Intercellular Signaling Peptides and Proteins/metabolism
- Intracellular Signaling Peptides and Proteins/genetics
- Intracellular Signaling Peptides and Proteins/metabolism
- Melanoma, Experimental/blood supply
- Melanoma, Experimental/metabolism
- Melanoma, Experimental/pathology
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Mice
- Mice, Inbred C57BL
- Neovascularization, Pathologic/genetics
- Neovascularization, Pathologic/metabolism
- Neovascularization, Pathologic/pathology
- Neovascularization, Physiologic
- Receptors, Notch/genetics
- Receptors, Notch/metabolism
- Signal Transduction
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Affiliation(s)
- Fabian Tetzlaff
- Division of Vascular Signaling and CancerGerman Cancer Research Center (DKFZ)HeidelbergGermany
- European Center for Angioscience, Medical Faculty MannheimHeidelberg UniversityMannheimGermany
| | - M Gordian Adam
- Division of Vascular Signaling and CancerGerman Cancer Research Center (DKFZ)HeidelbergGermany
| | - Anja Feldner
- Division of Vascular Signaling and CancerGerman Cancer Research Center (DKFZ)HeidelbergGermany
| | - Iris Moll
- Division of Vascular Signaling and CancerGerman Cancer Research Center (DKFZ)HeidelbergGermany
| | - Amitai Menuchin
- Department of Biochemistry and Molecular Biology, Wise Faculty of Life ScienceTel Aviv UniversityTel AvivIsrael
| | - Juan Rodriguez-Vita
- Division of Vascular Signaling and CancerGerman Cancer Research Center (DKFZ)HeidelbergGermany
| | - David Sprinzak
- Department of Biochemistry and Molecular Biology, Wise Faculty of Life ScienceTel Aviv UniversityTel AvivIsrael
| | - Andreas Fischer
- Division of Vascular Signaling and CancerGerman Cancer Research Center (DKFZ)HeidelbergGermany
- European Center for Angioscience, Medical Faculty MannheimHeidelberg UniversityMannheimGermany
- Medical Clinic I, Endocrinology and Clinical ChemistryHeidelberg University HospitalHeidelbergGermany
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7
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Adam MG, Berger C, Feldner A, Yang WJ, Wüstehube-Lausch J, Herberich SE, Pinder M, Gesierich S, Hammes HP, Augustin HG, Fischer A. Synaptojanin-2 binding protein stabilizes the Notch ligands DLL1 and DLL4 and inhibits sprouting angiogenesis. Circ Res 2013; 113:1206-18. [PMID: 24025447 DOI: 10.1161/circresaha.113.301686] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE The formation of novel blood vessels is initiated by vascular endothelial growth factor. Subsequently, DLL4-Notch signaling controls the selection of tip cells, which guide new sprouts, and trailing stalk cells. Notch signaling in stalk cells is induced by DLL4 on the tip cells. Moreover, DLL4 and DLL1 are expressed in the stalk cell plexus to maintain Notch signaling. Notch loss-of-function causes formation of a hyperdense vascular network with disturbed blood flow. OBJECTIVE This study was aimed at identifying novel modifiers of Notch signaling that interact with the intracellular domains of DLL1 and DLL4. METHODS AND RESULTS Synaptojanin-2 binding protein (SYNJ2BP, also known as ARIP2) interacted with the PDZ binding motif of DLL1 and DLL4, but not with the Notch ligand Jagged-1. SYNJ2BP was preferentially expressed in stalk cells, enhanced DLL1 and DLL4 protein stability, and promoted Notch signaling in endothelial cells. SYNJ2BP induced expression of the Notch target genes HEY1, lunatic fringe (LFNG), and ephrin-B2, reduced phosphorylation of ERK1/2, and decreased expression of the angiogenic factor vascular endothelial growth factor (VEGF)-C. It inhibited the expression of genes enriched in tip cells, such as angiopoietin-2, ESM1, and Apelin, and impaired tip cell formation. SYNJ2BP inhibited endothelial cell migration, proliferation, and VEGF-induced angiogenesis. This could be rescued by blockade of Notch signaling or application of angiopoietin-2. SYNJ2BP-silenced human endothelial cells formed a functional vascular network in immunocompromised mice with significantly increased vascular density. CONCLUSIONS These data identify SYNJ2BP as a novel inhibitor of tip cell formation, executing its functions predominately by promoting Delta-Notch signaling.
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Affiliation(s)
- M Gordian Adam
- From Division of Vascular Signaling and Cancer (M.G.A., C.B., A.F., W.-J.Y., S.E.H., A.F.) and Division of Vascular Oncology and Metastasis (S.G., H.G.A.), German Cancer Research Center (DKFZ-ZMBH Alliance), Heidelberg, Germany; Division of Vascular Biology and Tumor Angiogenesis (M.G.A., C.B., W.-J.Y., J.W.-L., S.E.H., M.P., H.G.A., A.F.) and Fifth Medical Department (H.-P.H.), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; and BioNTech AG, Mainz, Germany (J.W.-L.)
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8
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No evidence for a functional role of bi-directional Notch signaling during angiogenesis. PLoS One 2012; 7:e53074. [PMID: 23300864 PMCID: PMC3532505 DOI: 10.1371/journal.pone.0053074] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Accepted: 11/23/2012] [Indexed: 11/19/2022] Open
Abstract
The Delta-Notch pathway is a signal exchanger between adjacent cells to regulate numerous differentiation steps during embryonic development. Blood vessel formation by sprouting angiogenesis requires high expression of the Notch ligand DLL4 in the leading tip cell, while Notch receptors in the trailing stalk cells are activated by DLL4 to achieve strong Notch signaling activity. Upon ligand binding, Notch receptors are cleaved by ADAM proteases and gamma-secretase. This releases the intracellular Notch domain that acts as a transcription factor. There is evidence that also Notch ligands (DLL1, DLL4, JAG1, JAG2) are processed upon receptor binding to influence transcription in the ligand-expressing cell. Thus, the existence of bi-directional Delta-Notch signaling has been proposed. We report here that the Notch ligands DLL1 and JAG1 are processed in endothelial cells in a gamma-secretase-dependent manner and that the intracellular ligand domains accumulate in the cell nucleus. Overexpression of JAG1 intracellular domain (ICD) as well as DLL1-ICD, DLL4-ICD and NOTCH1-ICD inhibited endothelial proliferation. Whereas NOTCH1-ICD strongly repressed endothelial migration and sprouting angiogenesis, JAG1-ICD, DLL1-ICD and DLL4-ICD had no significant effects. Consistently, global gene expression patterns were only marginally affected by the processed Notch ligands. In addition to its effects as a transcription factor, NOTCH1-ICD promotes cell adhesion to the extracellular matrix in a transcription-independent manner. However, JAG1-ICD, DLL1-ICD and DLL4-ICD did not influence endothelial cell adhesion. In summary, reverse signaling of Notch ligands appears to be dispensable for angiogenesis in cellular systems.
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9
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Generation of Venus reporter knock-in mice revealed MAGI-2 expression patterns in adult mice. Gene Expr Patterns 2012; 12:95-101. [DOI: 10.1016/j.gep.2012.01.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 12/13/2011] [Accepted: 01/28/2012] [Indexed: 11/17/2022]
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10
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Mo JS, Ann EJ, Yoon JH, Jung J, Choi YH, Kim HY, Ahn JS, Kim SM, Kim MY, Hong JA, Seo MS, Lang F, Choi EJ, Park HS. Serum- and glucocorticoid-inducible kinase 1 (SGK1) controls Notch1 signaling by downregulation of protein stability through Fbw7 ubiquitin ligase. J Cell Sci 2010; 124:100-12. [PMID: 21147854 DOI: 10.1242/jcs.073924] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Notch is a transmembrane protein that acts as a transcriptional factor in the Notch signaling pathway for cell survival, cell death and cell differentiation. Notch1 and Fbw7 mutations both lead the activation of the Notch1 pathway and are found in the majority of patients with the leukemia T-ALL. However, little is known about the mechanisms and regulators that are responsible for attenuating the Notch signaling pathway through Fbw7. Here, we report that the serum- and glucocorticoid-inducible protein kinase SGK1 remarkably reduced the protein stability of the active form of Notch1 through Fbw7. The protein level and transcriptional activity of the Notch1 intracellular domain (Notch1-IC) were higher in SGK1-deficient cells than in SGK1 wild-type cells. Notch1-IC was able to form a trimeric complex with Fbw7 and SGK1, thereby SGK1 enhanced the protein degradation of Notch1-IC via a Fbw7-dependent proteasomal pathway. Furthermore, activated SGK1 phosphorylated Fbw7 at serine 227, an effect inducing Notch1-IC protein degradation and ubiquitylation. Moreover, accumulated dexamethasone-induced SGK1 facilitated the degradation of Notch1-IC through phosphorylation of Fbw7. Together our results suggest that SGK1 inhibits the Notch1 signaling pathway via phosphorylation of Fbw7.
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Affiliation(s)
- Jung-Soon Mo
- Hormone Research Center, School of Biological Sciences and Technology, Chonnam National University, Gwangju 500-757, Republic of Korea
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11
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Abstract
Notch signaling induced by canonical Notch ligands is critical for normal embryonic development and tissue homeostasis through the regulation of a variety of cell fate decisions and cellular processes. Activation of Notch signaling is normally tightly controlled by direct interactions with ligand-expressing cells, and dysregulated Notch signaling is associated with developmental abnormalities and cancer. While canonical Notch ligands are responsible for the majority of Notch signaling, a diverse group of structurally unrelated noncanonical ligands has also been identified that activate Notch and likely contribute to the pleiotropic effects of Notch signaling. Soluble forms of both canonical and noncanonical ligands have been isolated, some of which block Notch signaling and could serve as natural inhibitors of this pathway. Ligand activity can also be indirectly regulated by other signaling pathways at the level of ligand expression, serving to spatiotemporally compartmentalize Notch signaling activity and integrate Notch signaling into a molecular network that orchestrates developmental events. Here, we review the molecular mechanisms underlying the dual role of Notch ligands as activators and inhibitors of Notch signaling. Additionally, evidence that Notch ligands function independent of Notch is presented. We also discuss how ligand posttranslational modification, endocytosis, proteolysis, and spatiotemporal expression regulate their signaling activity.
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Affiliation(s)
- Brendan D'Souza
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
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12
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Abstract
Notch signaling regulates many aspects of metazoan development and tissue renewal. Accordingly, the misregulation or loss of Notch signaling underlies a wide range of human disorders, from developmental syndromes to adult-onset diseases and cancer. Notch signaling is remarkably robust in most tissues even though each Notch molecule is irreversibly activated by proteolysis and signals only once without amplification by secondary messenger cascades. In this Review, we highlight recent studies in Notch signaling that reveal new molecular details about the regulation of ligand-mediated receptor activation, receptor proteolysis, and target selection.
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13
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Choi K, Ahn YH, Gibbons DL, Tran HT, Creighton CJ, Girard L, Minna JD, Qin FXF, Kurie JM. Distinct biological roles for the notch ligands Jagged-1 and Jagged-2. J Biol Chem 2009; 284:17766-74. [PMID: 19398556 DOI: 10.1074/jbc.m109.003111] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Notch signaling is activated in a subset of non-small cell lung cancer cells because of overexpression of Notch3, but the role of Notch ligands has not been fully defined. On the basis of gene expression profiling of a panel of non-small cell lung cancer cell lines, we found that the predominant Notch ligands were JAG1, JAG2, DLL1, and DLL3. Given that Notch ligands reportedly have overlapping receptor binding specificities, we postulated that they have redundant biological roles. Arguing against this hypothesis, we found that JAG1 and JAG2 were differentially regulated; JAG1 expression was dependent upon epidermal growth factor receptor (EGFR) activation in HCC827 cells, which require EGFR for survival, whereas JAG2 expression was EGFR-independent in these cells. Furthermore, HCC827 cells underwent apoptosis following depletion of JAG1 but not JAG2, whereas co-culture experiments revealed that depletion of JAG2, but not JAG1, enhanced the ability of HCC827 cells to chemoattract THP-1 human monocytes. JAG2-depleted HCC827 cells expressed high levels of inflammation-related genes, including interleukin 1 (IL1) and a broad range of IL1-regulated cytokines, which was attenuated by inhibition of IL1 receptor (IL1R). Our findings suggest that JAG1 and JAG2 have distinct biological roles including a previously undiscovered role for JAG2 in regulating the expression of cytokines that can promote antitumor immunity.
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Affiliation(s)
- Kuicheon Choi
- Department of Thoracic/Head and Neck Medical Oncology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA
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14
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Abstract
The Notch signaling pathway regulates a diverse array of cell types and cellular processes and is tightly regulated by ligand binding. Both canonical and noncanonical Notch ligands have been identified that may account for some of the pleiotropic nature associated with Notch signaling. This review focuses on the molecular mechanisms by which Notch ligands function as signaling agonists and antagonists, and discusses different modes of activating ligands as well as findings that support intrinsic ligand signaling activity independent of Notch. Post-translational modification, proteolytic processing, endocytosis and membrane trafficking, as well as interactions with the actin cytoskeleton may contribute to the recently appreciated multifunctionality of Notch ligands. The regulation of Notch ligand expression by other signaling pathways provides a mechanism to coordinate Notch signaling with multiple cellular and developmental cues. The association of Notch ligands with inherited human disorders and cancer highlights the importance of understanding the molecular nature and activities intrinsic to Notch ligands. Oncogene (2008) 27, 5148-5167; doi:10.1038/onc.2008.229.
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Affiliation(s)
- B D'Souza
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095-1737, USA
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15
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Abstract
ADAM metalloproteases play important roles in development and disease. One of the key functions of ADAMs is the proteolytic processing of Notch receptors and their ligands. ADAM-mediated cleavage of Notch represents the first step in regulated intramembrane proteolysis of the receptor, leading to activation of the Notch pathway. Recent reports indicate that the transmembrane Notch ligands also undergo ADAM-mediated processing in cultured cells and in vivo. The proteolytic processing of Notch ligands modulates the strength and duration of Notch signals, leads to generation of soluble intracellular domains of the ligands, and may support a bi-directional signaling between cells.
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Affiliation(s)
- A Zolkiewska
- Department of Biochemistry, Kansas State University, Manhattan, KS 66506, USA.
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16
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Holderfield MT, Hughes CC. Crosstalk Between Vascular Endothelial Growth Factor, Notch, and Transforming Growth Factor-β in Vascular Morphogenesis. Circ Res 2008; 102:637-52. [DOI: 10.1161/circresaha.107.167171] [Citation(s) in RCA: 259] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Vascular morphogenesis encompasses a temporally regulated set of morphological changes that endothelial cells undergo to generate a network of interconnected tubules. Such a complex process inevitably involves multiple cell signaling pathways that must be tightly coordinated in time and space. The formation of a new capillary involves endothelial cell activation, migration, alignment, proliferation, tube formation, branching, anastomosis, and maturation of intercellular junctions and the surrounding basement membrane. Each of these stages is either known or suspected to fall under the influence of the vascular endothelial growth factor, notch, and transforming growth factor-β/bone morphogenetic protein signaling pathways. Vascular endothelial growth factor is essential for initiation of angiogenic sprouting, and also regulates migration of capillary tip cells, proliferation of trunk cells, and gene expression in both. Notch has been implicated in the regulation of cell fate decisions in the vasculature, especially the choice between arterial and venular endothelial cells, and between tip and trunk cell phenotype. Transforming growth factor-β regulates cell migration and proliferation, as well as matrix synthesis. In this review, we emphasize how crosstalk between these pathways is essential for proper patterning of the vasculature and offer a transcriptional oscillator model to explain how these pathways might interact to generate new tip cells during retinal angiogenesis.
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Affiliation(s)
- Matthew T. Holderfield
- From the Department of Molecular Biology & Biochemistry, University of California, Irvine
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17
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Kim MY, Ann EJ, Kim JY, Mo JS, Park JH, Kim SY, Seo MS, Park HS. Tip60 histone acetyltransferase acts as a negative regulator of Notch1 signaling by means of acetylation. Mol Cell Biol 2007; 27:6506-19. [PMID: 17636029 PMCID: PMC2099611 DOI: 10.1128/mcb.01515-06] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The Notch signaling pathway appears to perform an important function in a wide variety of organisms and cell types. In our present study, we provide evidence that UV irradiation-induced Tip60 proteins reduced Notch1 activity to a marked degree. Accumulated UV irradiation-induced Tip60 suppresses Notch1 transcriptional activity via the dissociation of the Notch1-IC-CSL complex. The binding between endogenous Tip60 and Notch1-IC in UV radiation-exposed cells was verified in this study by coimmunoprecipitation. Interestingly, the physical interaction of Tip60 with Notch1-IC occurs to a more profound degree in the presence of CSL but does not exist in a trimeric complex. Using Notch1-IC and Tip60 deletion mutants, we also determined that the N terminus, which harbors the RAM domain and seven ankyrin repeats of Notch1-IC, interacts with the zinc finger and acetyl coenzyme A domains of Tip60. Furthermore, here we report that Notch1-IC is a direct target of the acetyltransferase activity of Tip60. Collectively, our data suggest that Tip60 is an inhibitor of the Notch1 signaling pathway and that Tip60-dependent acetylation of Notch1-IC may be relevant to the mechanism by which Tip60 suppresses Notch1 signaling.
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Affiliation(s)
- Mi-Yeon Kim
- Hormonre Research Center, School of Biological Sciences and Technology, Chonnam National University, Yongbong-dong, Buk-ku, Gwangju 500-757, South Korea
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18
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Pintar A, De Biasio A, Popovic M, Ivanova N, Pongor S. The intracellular region of Notch ligands: does the tail make the difference? Biol Direct 2007; 2:19. [PMID: 17623096 PMCID: PMC1965462 DOI: 10.1186/1745-6150-2-19] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2007] [Accepted: 07/10/2007] [Indexed: 02/06/2023] Open
Abstract
The cytoplasmic tail of Notch ligands drives endocytosis, mediates association with proteins implicated in the organization of cell-cell junctions and, through regulated intra-membrane proteolysis, is released from the membrane as a signaling fragment. We survey these findings and discuss the role of Notch ligands intracellular region in bidirectional signaling and possibly in signal modulation in mammals. This article was reviewed by Frank Eisenhaber, L Aravind, and Eugene V. Koonin.
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Affiliation(s)
- Alessandro Pintar
- International Centre for Genetic Engineering and Biotechnology, Protein Structure and Bioinformatics Group, AREA Science Park, Padriciano 99, I-34012 Trieste, Italy.
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19
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Hiratochi M, Nagase H, Kuramochi Y, Koh CS, Ohkawara T, Nakayama K. The Delta intracellular domain mediates TGF-beta/Activin signaling through binding to Smads and has an important bi-directional function in the Notch-Delta signaling pathway. Nucleic Acids Res 2007; 35:912-22. [PMID: 17251195 PMCID: PMC1807952 DOI: 10.1093/nar/gkl1128] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Delta is a major transmembrane ligand for Notch receptor that mediates numerous cell fate decisions. The Notch signaling pathway has long been thought to be mono-directional, because ligands for Notch were generally believed to be unable to transmit signals into the cells expressing them. However, we showed here that Notch also supplies signals to neighboring mouse neural stem cells (NSCs). To investigate the Notch-Delta signaling pathway in a bi-directional manner, we analyzed functional roles of the intracellular domain of mouse Delta like protein 1 (Dll1IC). In developing mouse NSCs, Dll1IC, which is released from cell membrane by proteolysis, is present in the nucleus. Furthermore, we screened for transcription factors that bind to Dll1IC and demonstrated that Dll1IC binds specifically to transcription factors involved in TGF-beta/Activin signaling--Smad2, Smad3 and Smad4--and enhances Smad-dependent transcription. In addition, the results of the present study indicated that over-expression of Dll1IC in embryonic carcinoma P19 cells induced neurons, and this induction was blocked by SB431542, which is a specific inhibitor of TGF-beta/Activin signaling. These observations strongly suggested that Dll1IC mediates TGF-beta/Activin signaling through binding to Smads and plays an important role for bi-directional Notch-Delta signaling pathway.
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Affiliation(s)
- Masahiro Hiratochi
- Department of Anatomy, Shinshu University, School of Medicine, Matsumoto, Nagano 390-8621, Japan Department of Molecular Oncology, Shinshu University, School of Medicine, Matsumoto, Nagano 390-8621, Japan Department of Immunology and Infectious Diseases, Shinshu University, School of Medicine, Matsumoto, Nagano 390-8621, Japan, Department of Biomedical Sciences, Shinshu University, School of Health Sciences, Matsumoto, Nagano 390-8621, Japan and Discovery Research II, Kissei Pharmaceutical Co., Ltd., Azumino, Nagano 399-8304, Japan
| | - Hisashi Nagase
- Department of Anatomy, Shinshu University, School of Medicine, Matsumoto, Nagano 390-8621, Japan Department of Molecular Oncology, Shinshu University, School of Medicine, Matsumoto, Nagano 390-8621, Japan Department of Immunology and Infectious Diseases, Shinshu University, School of Medicine, Matsumoto, Nagano 390-8621, Japan, Department of Biomedical Sciences, Shinshu University, School of Health Sciences, Matsumoto, Nagano 390-8621, Japan and Discovery Research II, Kissei Pharmaceutical Co., Ltd., Azumino, Nagano 399-8304, Japan
| | - Yu Kuramochi
- Department of Anatomy, Shinshu University, School of Medicine, Matsumoto, Nagano 390-8621, Japan Department of Molecular Oncology, Shinshu University, School of Medicine, Matsumoto, Nagano 390-8621, Japan Department of Immunology and Infectious Diseases, Shinshu University, School of Medicine, Matsumoto, Nagano 390-8621, Japan, Department of Biomedical Sciences, Shinshu University, School of Health Sciences, Matsumoto, Nagano 390-8621, Japan and Discovery Research II, Kissei Pharmaceutical Co., Ltd., Azumino, Nagano 399-8304, Japan
| | - Chang-Sung Koh
- Department of Anatomy, Shinshu University, School of Medicine, Matsumoto, Nagano 390-8621, Japan Department of Molecular Oncology, Shinshu University, School of Medicine, Matsumoto, Nagano 390-8621, Japan Department of Immunology and Infectious Diseases, Shinshu University, School of Medicine, Matsumoto, Nagano 390-8621, Japan, Department of Biomedical Sciences, Shinshu University, School of Health Sciences, Matsumoto, Nagano 390-8621, Japan and Discovery Research II, Kissei Pharmaceutical Co., Ltd., Azumino, Nagano 399-8304, Japan
| | - Takeshi Ohkawara
- Department of Anatomy, Shinshu University, School of Medicine, Matsumoto, Nagano 390-8621, Japan Department of Molecular Oncology, Shinshu University, School of Medicine, Matsumoto, Nagano 390-8621, Japan Department of Immunology and Infectious Diseases, Shinshu University, School of Medicine, Matsumoto, Nagano 390-8621, Japan, Department of Biomedical Sciences, Shinshu University, School of Health Sciences, Matsumoto, Nagano 390-8621, Japan and Discovery Research II, Kissei Pharmaceutical Co., Ltd., Azumino, Nagano 399-8304, Japan
| | - Kohzo Nakayama
- Department of Anatomy, Shinshu University, School of Medicine, Matsumoto, Nagano 390-8621, Japan Department of Molecular Oncology, Shinshu University, School of Medicine, Matsumoto, Nagano 390-8621, Japan Department of Immunology and Infectious Diseases, Shinshu University, School of Medicine, Matsumoto, Nagano 390-8621, Japan, Department of Biomedical Sciences, Shinshu University, School of Health Sciences, Matsumoto, Nagano 390-8621, Japan and Discovery Research II, Kissei Pharmaceutical Co., Ltd., Azumino, Nagano 399-8304, Japan
- *To whom correspondence should be addressed. Tel/Fax: +81 263 37 2594; E-mail:
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20
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Rubio-Aliaga I, Soewarto D, Wagner S, Klaften M, Fuchs H, Kalaydjiev S, Busch DH, Klempt M, Rathkolb B, Wolf E, Abe K, Zeiser S, Przemeck GKH, Beckers J, de Angelis MH. A genetic screen for modifiers of the delta1-dependent notch signaling function in the mouse. Genetics 2006; 175:1451-63. [PMID: 17179084 PMCID: PMC1840053 DOI: 10.1534/genetics.106.067298] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The Notch signaling pathway is an evolutionarily conserved transduction pathway involved in embryonic patterning and regulation of cell fates during development. Recent studies have demonstrated that this pathway is integral to a complex system of interactions, which are also involved in distinct human diseases. Delta1 is one of the known ligands of the Notch receptors. Mice homozygous for a loss-of-function allele of the Delta1 gene Dll1(lacZ/lacZ) die during embryonic development. Here, we present the results of two phenotype-driven modifier screens. Heterozygous Dll1(lacZ) knockout animals were crossed with ENU-mutagenized mice and screened for dysmorphological, clinical chemical, and immunological variants that are dependent on the Delta1 loss-of-function allele. First, we show that mutagenized heterozygous Dll1(lacZ) offspring have reduced body weight and altered specific clinical chemical parameters, including changes in metabolites and electrolytes relevant for kidney function. In our mutagenesis screen we have successfully generated 35 new mutant lines. Of major interest are 7 mutant lines that exhibit a Dll1(lacZ/+)-dependent phenotype. These mutant mouse lines provide excellent in vivo tools for studying the role of Notch signaling in kidney and liver function, cholesterol and iron metabolism, cell-fate decisions, and during maturation of T cells in the immune system.
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Affiliation(s)
- Isabel Rubio-Aliaga
- Institute of Experimental Genetics, GSF Research Center for Environment and Health, 85764 Neuherberg, Germany
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21
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Abstract
A small number of signalling pathways are used iteratively to regulate cell fates, cell proliferation and cell death in development. Notch is the receptor in one such pathway, and is unusual in that most of its ligands are also transmembrane proteins; therefore signalling is restricted to neighbouring cells. Although the intracellular transduction of the Notch signal is remarkably simple, with no secondary messengers, this pathway functions in an enormous diversity of developmental processes and its dysfunction is implicated in many cancers.
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Affiliation(s)
- Sarah J Bray
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3DY, UK.
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22
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Deng F, Price MG, Davis CF, Mori M, Burgess DL. Stargazin and other transmembrane AMPA receptor regulating proteins interact with synaptic scaffolding protein MAGI-2 in brain. J Neurosci 2006; 26:7875-84. [PMID: 16870733 PMCID: PMC6674230 DOI: 10.1523/jneurosci.1851-06.2006] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The spatial coordination of neurotransmitter receptors with other postsynaptic signaling and structural molecules is regulated by a diverse array of cell-specific scaffolding proteins. The synaptic trafficking of AMPA receptors by the stargazin protein in some neurons, for example, depends on specific interactions between the C terminus of stargazin and the PDZ [postsynaptic density-95 (PSD-95)/Discs large/zona occludens-1] domains of membrane-associated guanylate kinase scaffolding proteins PSD-93 or PSD-95. Stargazin [Cacng2 (Ca2+ channel gamma2 subunit)] is one of four closely related proteins recently categorized as transmembrane AMPA receptor regulating proteins (TARPs) that appear to share similar functions but exhibit distinct expression patterns in the CNS. We used yeast two-hybrid screening to identify MAGI-2 (membrane associated guanylate kinase, WW and PDZ domain containing 2) as a novel candidate interactor with the cytoplasmic C termini of the TARPs. MAGI-2 [also known as S-SCAM (synaptic scaffolding molecule)] is a multi-PDZ domain scaffolding protein that interacts with several different ligands in brain, including PTEN (phosphatase and tensin homolog), dasm1 (dendrite arborization and synapse maturation 1), dendrin, axin, beta- and delta-catenin, neuroligin, hyperpolarization-activated cation channels, beta1-adrenergic receptors, and NMDA receptors. We confirmed that MAGI-2 coimmunoprecipitated with stargazin in vivo from mouse cerebral cortex and used in vitro assays to localize the interaction to the C-terminal -TTPV amino acid motif of stargazin and the PDZ1, PDZ3, and PDZ5 domains of MAGI-2. Expression of stargazin recruited MAGI-2 to cell membranes and cell-cell contact sites in transfected HEK-293T cells dependent on the presence of the stargazin -TTPV motif. These experiments identify MAGI-2 as a strong candidate for linking TARP/AMPA receptor complexes to a wide range of other postsynaptic molecules and pathways and advance our knowledge of protein interactions at mammalian CNS synapses.
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23
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Abstract
A number of recent studies have shown that endocytosis of Notch ligands is required for activation of Notch. There are at least two broad models that account for how Delta endocytosis in one cell might contribute to activation of Notch in the neighboring cell. The first class of models is related to the possibility that Delta endocytosis facilitates S2 cleavage and removal of the Notch extracellular domain, a critical step in Notch activation. A second class of models is related to the possibility that Delta ubiquitylation and endocytosis facilitates interactions between Delta and Notch. In the second set of models, Delta undergoes endocytosis and its subsequent trafficking back to the surface, following modifications or some change in the context in which it is presented, makes Delta a more effective ligand. Though it is still not clear how either or both mechanisms contribute, recent evidence points to the importance of both endocytosis and recycling in Delta signaling.
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Affiliation(s)
- Ajay Chitnis
- Laboratory of Molecular Genetics, National Institute of Child Health and Human Development, National Institutes of Health, 6 Center Drive, 3B 315, Bethesda, MD 20892, USA.
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24
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Kolev V, Kacer D, Trifonova R, Small D, Duarte M, Soldi R, Graziani I, Sideleva O, Larman B, Maciag T, Prudovsky I. The intracellular domain of Notch ligand Delta1 induces cell growth arrest. FEBS Lett 2005; 579:5798-5802. [PMID: 16225865 DOI: 10.1016/j.febslet.2005.09.042] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2005] [Accepted: 09/17/2005] [Indexed: 10/25/2022]
Abstract
Notch signaling involves proteolytic cleavage of the transmembrane Notch receptor after binding to its transmembrane ligands, Delta or Jagged; and the resultant soluble intracellular domain of Notch stimulates a cascade of transcriptional events. The Delta1 ligand also undergoes proteolytic cleavage upon Notch binding, resulting in the production of a free intracellular domain. We demonstrate that the expression of the intracellular domain of Delta1 results in a non-proliferating senescent-like cell phenotype which is dependent on the expression of the cell cycle inhibitor, p21, and is abolished by co-expression of constitutively active Notch1. These data suggest a new intracellular role for Delta1.
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Affiliation(s)
- Vihren Kolev
- Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, 04074, USA
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25
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Williams CK, Li JL, Murga M, Harris AL, Tosato G. Up-regulation of the Notch ligand Delta-like 4 inhibits VEGF-induced endothelial cell function. Blood 2005; 107:931-9. [PMID: 16219802 PMCID: PMC1895896 DOI: 10.1182/blood-2005-03-1000] [Citation(s) in RCA: 291] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Delta-like 4 (Dll4), a membrane-bound ligand for Notch1 and Notch4, is selectively expressed in the developing endothelium and in some tumor endothelium, and it is induced by vascular endothelial growth factor (VEGF)-A and hypoxia. Gene targeting studies have shown that Dll4 is required for normal embryonic vascular remodeling, but the mechanisms underlying Dll4 regulatory functions are currently not defined. In this study, we generated primary human endothelial cells that overexpress Dll4 protein to study Dll4 function and mechanism of action. Human umbilical vein endothelial cells retrovirally transduced with Dll4 displayed reduced proliferative and migratory responses selectively to VEGF-A. Expression of VEGF receptor-2, the principal signaling receptor for VEGF-A in endothelial cells, and coreceptor neuropilin-1 was significantly decreased in Dll4-transduced endothelial cells. Consistent with Dll4 signaling through Notch, expression of HEY2, one of the transcription factors that mediates Notch function, was significantly induced in Dll4-overexpressing endothelial cells. The gamma-secretase inhibitor L-685458 significantly reconstituted endothelial cell proliferation inhibited by immobilized extracellular Dll4 and reconstituted VEGFR2 expression in Dll4-overexpressing endothelial cells. These results identify the Notch ligand Dll4 as a selective inhibitor of VEGF-A biologic activities down-regulating 2 VEGF receptors expressed on endothelial cells and raise the possibility that Dll4 may be exploited therapeutically to modulate angiogenesis.
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Affiliation(s)
- Cassin Kimmel Williams
- Experimental Transplantation and Immunology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
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26
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Ladi E, Nichols JT, Ge W, Miyamoto A, Yao C, Yang LT, Boulter J, Sun YE, Kintner C, Weinmaster G. The divergent DSL ligand Dll3 does not activate Notch signaling but cell autonomously attenuates signaling induced by other DSL ligands. ACTA ACUST UNITED AC 2005; 170:983-92. [PMID: 16144902 PMCID: PMC2171428 DOI: 10.1083/jcb.200503113] [Citation(s) in RCA: 211] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mutations in the DSL (Delta, Serrate, Lag2) Notch (N) ligand Delta-like (Dll) 3 cause skeletal abnormalities in spondylocostal dysostosis, which is consistent with a critical role for N signaling during somitogenesis. Understanding how Dll3 functions is complicated by reports that DSL ligands both activate and inhibit N signaling. In contrast to other DSL ligands, we show that Dll3 does not activate N signaling in multiple assays. Consistent with these findings, Dll3 does not bind to cells expressing any of the four N receptors, and N1 does not bind Dll3-expressing cells. However, in a cell-autonomous manner, Dll3 suppressed N signaling, as was found for other DSL ligands. Therefore, Dll3 functions not as an activator as previously reported but rather as a dedicated inhibitor of N signaling. As an N antagonist, Dll3 promoted Xenopus laevis neurogenesis and inhibited glial differentiation of mouse neural progenitors. Finally, together with the modulator lunatic fringe, Dll3 altered N signaling levels that were induced by other DSL ligands.
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Affiliation(s)
- Ena Ladi
- Department of Biological Chemistry, Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA
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27
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Tolar J, Osborn M, Bell S, McElmurry R, Xia L, Riddle M, Panoskaltsis-Mortari A, Jiang Y, McIvor RS, Contag CH, Yant SR, Kay MA, Verfaillie CM, Blazar BR. Real-Time in Vivo Imaging of Stem Cells Following Transgenesis by Transposition. Mol Ther 2005; 12:42-8. [PMID: 15963919 DOI: 10.1016/j.ymthe.2005.02.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2004] [Revised: 02/26/2005] [Accepted: 02/28/2005] [Indexed: 10/25/2022] Open
Abstract
Previous studies have identified Sleeping Beauty transposons as efficient vectors for nonviral gene delivery in mammalian cells. However, studies demonstrating the usefulness of transposons as gene delivery vehicles into adult stem cells are lacking. Multipotent adult progenitor cells (MAPC) are nonhematopoietic stem cells with the capacity to form most, if not all, cell types of the body and as such hold great therapeutic potential. The whole-body biodistribution and persistence of MAPC are unknown, and such data would help direct clinical applications. We have nucleofected murine MAPC with two plasmid-based Sleeping Beauty transposons encoding the red fluorescent protein (DsRed2) and firefly luciferase. Transgenic euploid MAPC clones maintained their characteristic multilineage differentiation potential in vitro. DsRed2 and luciferase expression allowed for MAPC detection in vivo and in tissue sections. To confirm that transgenesis occurred by transposition into the genome of MAPC, we mapped Sleeping Beauty transposon integration sites in two MAPC clones using splinkerette PCR. This novel dual-reporter imaging approach based on the transgenesis of MAPC with Sleeping Beauty transposons sheds light on the homing patterns of MAPC and paves the way for quantification of MAPC engraftment in real time in vivo.
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Affiliation(s)
- Jakub Tolar
- Department of Pediatrics, Division of Hematology, Oncology, Blood and Marrow Transplant Program, University of Minnesota, Minneapolis, MN 55455, USA.
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28
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Mizuhara E, Nakatani T, Minaki Y, Sakamoto Y, Ono Y, Takai Y. MAGI1 recruits Dll1 to cadherin-based adherens junctions and stabilizes it on the cell surface. J Biol Chem 2005; 280:26499-507. [PMID: 15908431 DOI: 10.1074/jbc.m500375200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Delta-Notch signaling plays an essential role in cell fate determination in many tissue types, including the central nervous system. Although the signaling mechanism of Notch has been extensively studied, the behaviors of its ligands are not well understood. In the present study, we found that, in the developing neural tube, Dll1(Delta-like 1) was mainly localized on the processes extending from nascent neurons toward both the pia and the ventricle and accumulated at apical termini, where adherens junctions (AJs) were formed. To understand the mechanism of Dll1 localization, we searched for binding proteins for Dll1 and identified a scaffolding molecule, MAGI1. In the developing spinal cord, MAGI1 mRNA was highly expressed in the ventricular zone, where Dll1 mRNA was expressed. MAGI1 protein accumulated at the AJs formed around the termini of apically extending processes and was partially colocalized with Dll1. MAGI1 bound not only to Dll1 but also to N-cadherin-beta-catenin complexes. In cultured AJ-forming fibroblasts, MAGI1 was localized at AJs, and Dll1 was recruited to these AJs through binding to MAGI1. In addition, Dll1 was stabilized on the cell surface by MAGI1. Taken together, these results suggest that Dll1 is presented on the surface of AJs formed at the apical termini of processes through interaction with MAGI1 to activate Notch on neighboring cells in the developing central nervous system.
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Affiliation(s)
- Eri Mizuhara
- KAN Research Institute Inc., 93 Chudoji-Awata-cho, Shimogyo-ku, Kyoto 600-8815, Japan
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29
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Wright GJ, Leslie JD, Ariza-McNaughton L, Lewis J. Delta proteins and MAGI proteins: an interaction of Notch ligands with intracellular scaffolding molecules and its significance for zebrafish development. Development 2005; 131:5659-69. [PMID: 15509766 DOI: 10.1242/dev.01417] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Delta proteins activate Notch through a binding reaction that depends on their extracellular domains; but the intracellular (C-terminal) domains of the Deltas also have significant functions. All classes of vertebrates possess a subset of Delta proteins with a conserved ATEV* motif at their C termini. These ATEV Deltas include Delta1 and Delta4 in mammals and DeltaD and DeltaC in the zebrafish. We show that these Deltas associate with the membrane-associated scaffolding proteins MAGI1, MAGI2 and MAGI3, through a direct interaction between the C termini of the Deltas and a specific PDZ domain (PDZ4) of the MAGIs. In cultured cells and in subsets of cells in the intact zebrafish embryo, DeltaD and MAGI1 are co-localized at the plasma membrane. The interaction and the co-localization can be abolished by injection of a morpholino that blocks the mRNA splicing reaction that gives DeltaD its terminal valine, on which the interaction depends. Embryos treated in this way appear normal with respect to some known functions of DeltaD as a Notch ligand, including the control of somite segmentation, neurogenesis, and hypochord formation. They do, however, show an anomalous distribution of Rohon-Beard neurons in the dorsal neural tube, suggesting that the Delta-MAGI interaction may play some part in the control of neuron migration.
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Affiliation(s)
- Gavin J Wright
- Vertebrate Development Laboratory, Cancer Research UK London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3PX, UK
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30
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Abstract
The Notch proteins encompass a family of transmembrane receptors that have been highly conserved through evolution as mediators of cell fate, and are comprised of 4 members in mammals (Notch1 to Notch4). Following intra cellular processing of the full-length protein, Notch is expressed at the cell surface as a heterodimeric receptor. Engagement by ligand results in a 2-step cleavage of the Notch heterodimer, releasing the intracellular domain of Notch and allowing translocation to the nucleus. The intracellular domain of Notch interacts with the DNA-binding factor, CSL, resulting in transactivation at various promoters, in particular those of various basic helix-loop-helix factors of the HES (Hairy and Enhancer of Split) and HRT families (Hairy-Related Transcription factor). Recent findings implicate Notch as playing a critical and non-redundant role in vascular development and maintenance. This article briefly reviews vessel development and Notch signaling and highlights studies that examine Notch functions such as proliferation, cell survival, migration, adhesion, and mesenchymal transformation in the vasculature. Human diseases caused by Notch pathway members are also discussed.Key words: vascular, endothelial, Notch, angiogenesis, mesenchymal transformation.
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Affiliation(s)
- Aly Karsan
- Department of Medical Biophysics, British Columbia Cancer Research Centre, Vancouver, BC, Canada.
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31
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Six EM, Ndiaye D, Sauer G, Laâbi Y, Athman R, Cumano A, Brou C, Israël A, Logeat F. The Notch Ligand Delta1 Recruits Dlg1 at Cell-Cell Contacts and Regulates Cell Migration. J Biol Chem 2004; 279:55818-26. [PMID: 15485825 DOI: 10.1074/jbc.m408022200] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Delta1 acts as a membrane-bound ligand that interacts with the Notch receptor and plays a critical role in cell fate specification. By using peptide affinity chromatography followed by mass spectrometry, we have identified Dlg1 as a partner of the Delta1 C-terminal region. Dlg1 is a human homolog of the Drosophila Discs large tumor suppressor, a member of the membrane-associated guanylate kinase family of molecular scaffolds. We confirmed this interaction by co-immunoprecipitation experiments between endogenous Dlg1 and transduced Delta1 in a 3T3 cell line stably expressing Delta1. Moreover, we showed that deletion of a canonical C-terminal PDZ-binding motif (ATEV) in Delta1 abrogated this interaction. Delta4 also interacted with Dlg1, whereas Jagged1, another Notch ligand, did not. In HeLa cells, transfected Delta1 triggered the accumulation of endogenous Dlg1 at sites of cell-cell contact. Expression of Delta1 also reduced the motility of 3T3 cells. Finally, deletion of the ATEV motif totally abolished these effects but did not interfere with the ability of Delta1 to induce Notch signaling and T cell differentiation in co-culture experiments. These results point to a new, probably cell-autonomous function of Delta1, which is independent of its activity as a Notch ligand.
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Affiliation(s)
- Emmanuelle M Six
- Unité de Biologie Moléculaire de l'Expression Génique, URA 2582 CNRS, Institut Pasteur, 25 Rue du Dr Roux, 75724 Paris Cedex 15, France
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32
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Smyth I, Van Agtmael T, Jackson IJ. 17th International Mouse Genome Conference. Mamm Genome 2004; 15:509-14. [PMID: 15366370 DOI: 10.1007/s00335-004-4001-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Ian Smyth
- MRC Human Genetics Unit, Western General Hospital, Crewe Rd., Edinburgh, EH4 2XU United Kingdom
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