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Fuentealba J, Toro-Tapia G, Rodriguez M, Arriagada C, Maureira A, Beyer A, Villaseca S, Leal JI, Hinrichs MV, Olate J, Caprile T, Torrejón M. Expression profiles of the Gα subunits during Xenopus tropicalis embryonic development. Gene Expr Patterns 2016; 22:15-25. [PMID: 27613600 DOI: 10.1016/j.gep.2016.09.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 07/31/2016] [Accepted: 09/04/2016] [Indexed: 10/21/2022]
Abstract
Heterotrimeric G protein signaling plays major roles during different cellular events. However, there is a limited understanding of the molecular mechanisms underlying G protein control during embryogenesis. G proteins are highly conserved and can be grouped into four subfamilies according to sequence homology and function. To further studies on G protein function during embryogenesis, the present analysis identified four Gα subunits representative of the different subfamilies and determined their spatiotemporal expression patterns during Xenopus tropicalis embryogenesis. Each of the Gα subunit transcripts was maternally and zygotically expressed, and, as development progressed, dynamic expression patterns were observed. In the early developmental stages, the Gα subunits were expressed in the animal hemisphere and dorsal marginal zone. While expression was observed at the somite boundaries, in vascular structures, in the eye, and in the otic vesicle during the later stages, expression was mainly found in neural tissues, such as the neural tube and, especially, in the cephalic vesicles, neural crest region, and neural crest-derived structures. Together, these results support the pleiotropism and complexity of G protein subfamily functions in different cellular events. The present study constitutes the most comprehensive description to date of the spatiotemporal expression patterns of Gα subunits during vertebrate development.
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Affiliation(s)
- Jaime Fuentealba
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Gabriela Toro-Tapia
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Marion Rodriguez
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Cecilia Arriagada
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Alejandro Maureira
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Andrea Beyer
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Soraya Villaseca
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Juan I Leal
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Maria V Hinrichs
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Juan Olate
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Teresa Caprile
- Departamento de Biología Celular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Marcela Torrejón
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile.
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Inhibition of Wnt signalling and breast tumour growth by the multi-purpose drug suramin through suppression of heterotrimeric G proteins and Wnt endocytosis. Biochem J 2016; 473:371-81. [DOI: 10.1042/bj20150913] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 11/24/2015] [Indexed: 11/17/2022]
Abstract
Multi-purpose drug suramin is found to be active against cancer-related Wnt signalling. As a consequence of heterotrimeric G proteins suppression, suramin inhibits Wnt ligand internalization, which renders the drug active against triple-negative breast cancer (TNBC).
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Fuentealba J, Toro-Tapia G, Arriagada C, Riquelme L, Beyer A, Henriquez JP, Caprile T, Mayor R, Marcellini S, Hinrichs MV, Olate J, Torrejón M. Ric-8A, a guanine nucleotide exchange factor for heterotrimeric G proteins, is critical for cranial neural crest cell migration. Dev Biol 2013; 378:74-82. [PMID: 23588098 DOI: 10.1016/j.ydbio.2013.04.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 04/05/2013] [Accepted: 04/05/2013] [Indexed: 01/02/2023]
Abstract
The neural crest (NC) is a transient embryonic structure induced at the border of the neural plate. NC cells extensively migrate towards diverse regions of the embryo, where they differentiate into various derivatives, including most of the craniofacial skeleton and the peripheral nervous system. The Ric-8A protein acts as a guanine nucleotide exchange factor for several Gα subunits, and thus behaves as an activator of signaling pathways mediated by heterotrimeric G proteins. Using in vivo transplantation assays, we demonstrate that Ric-8A levels are critical for the migration of cranial NC cells and their subsequent differentiation into craniofacial cartilage during Xenopus development. NC cells explanted from Ric-8A morphant embryos are unable to migrate directionally towards a source of the Sdf1 peptide, a potent chemoattractant for NC cells. Consistently, Ric-8A knock-down showed anomalous radial migratory behavior, displaying a strong reduction in cell spreading and focal adhesion formation. We further show that during in vivo and in vitro neural crest migration, Ric-8A localizes to the cell membrane, in agreement with its role as a G protein activator. We propose that Ric-8A plays essential roles during the migration of cranial NC cells, possibly by regulating cell adhesion and spreading.
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Affiliation(s)
- Jaime Fuentealba
- Department of Biochemistry and Molecular Biology, Faculty of Biological Sciences, University of Concepcion, Chile
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Abstract
Genetic studies of Wnt11 have revealed many insights into the roles and regulation of Wnt11, particularly during development. New tools to study Wnt11 have recently become available, making it timely to review the literature regarding this unique Wnt family member. In this study, we focus on mammalian Wnt11, describing its main sites of expression during development, and how the Wnt11 gene is regulated. We highlight an emerging theme in which canonical Wnt signals regulate Wnt11 expression through transcription factors in addition to, or other than, Tcf/LEF family members. We also discuss the frizzled family and other receptors that bind to Wnt11, the intracellular kinases and small GTPases that act downstream of Wnt11, and the effects of Wnt11 on Wnt/β-catenin signalling. Finally, we elaborate on the relevance of Wnt11 to human cancer, where it appears to be important both for proliferation and/or survival during normal differentiation and for migration/invasion.
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Affiliation(s)
- P Uysal-Onganer
- Department of Surgery and Cancer, Imperial College London, UK
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Najafi SMA. Activators of G proteins inhibit GSK-3beta and stabilize beta-Catenin in Xenopus oocytes. Biochem Biophys Res Commun 2009; 382:365-9. [PMID: 19285033 DOI: 10.1016/j.bbrc.2009.03.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Accepted: 03/05/2009] [Indexed: 12/13/2022]
Abstract
Frizzled proteins, the receptors for Wnt ligands have seven hydrophobic transmembrane domains, a structural feature of G protein coupled receptors. Therefore a role for G proteins in the regulation of Wnt signaling has been proposed. Here I have used Xenopus oocytes to study the role of heterotrimeric G proteins in the regulation of GSK-3beta and beta-Catenin, two essential components of the canonical Wnt pathway. In these cells, general activators of G proteins such as GTPgamma-S and AlF4(-) increase beta-Catenin stability and decrease GSK-3beta mediated phosphorylation of the microtubule associated protein, Tau. Among several members of Galpha proteins tested, expression of a constitutively active mutant of Galphaq (GalphaqQL) led to a significant increase in accumulation of beta-Catenin. The stabilization of beta-Catenin mediated by Galphaq was reversed by a Galphaq specific inhibitor, Gp-antagonist 2A, but not by a specific blocking peptide for Galphas. Expression of GalphaqQL also inhibited GSK-3beta-mediated tau phosphorylation in Xenopus oocytes. These results support a role for the Gq class of G proteins in the regulation of Wnt/beta-Catenin signal transduction.
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Affiliation(s)
- S Mahmoud A Najafi
- Department of Cell & Molecular Biology, School of Biology, University College of Science, University of Tehran, Tehran, Iran.
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