1
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Lancaster CL, Yalamanchili PS, Goldy JN, Leung SW, Corbett AH, Moberg KH. The RNA-binding protein Nab2 regulates levels of the RhoGEF Trio to govern axon and dendrite morphology. Mol Biol Cell 2024; 35:ar109. [PMID: 38985523 DOI: 10.1091/mbc.e24-04-0150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/12/2024] Open
Abstract
The Drosophila RNA-binding protein (RBP) Nab2 acts in neurons to regulate neurodevelopment and is orthologous to the human intellectual disability-linked RBP, ZC3H14. Nab2 governs axon projection in mushroom body neurons and limits dendritic arborization of class IV sensory neurons in part by regulating splicing events in ∼150 mRNAs. Analysis of the Sex-lethal (Sxl) mRNA revealed that Nab2 promotes an exon-skipping event and regulates m6A methylation on Sxl pre-mRNA by the Mettl3 methyltransferase. Mettl3 heterozygosity broadly rescues Nab2null phenotypes implying that Nab2 acts through similar mechanisms on other RNAs, including unidentified targets involved in neurodevelopment. Here, we show that Nab2 and Mettl3 regulate the removal of a 5'UTR (untranslated region) intron in the trio pre-mRNA. Trio utilizes two GEF domains to balance Rac and RhoGTPase activity. Intriguingly, an isoform of Trio containing only the RhoGEF domain, GEF2, is depleted in Nab2null nervous tissue. Expression of Trio-GEF2 rescues projection defects in Nab2null axons and dendrites, while the GEF1 Rac1-regulatory domain exacerbates these defects, suggesting Nab2-mediated regulation Trio-GEF activities. Collectively, these data indicate that Nab2-regulated processing of trio is critical for balancing Trio-GEF1 and -GEF2 activity and show that Nab2, Mettl3, and Trio function in a common pathway that shapes axon and dendrite morphology.
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Affiliation(s)
- Carly L Lancaster
- Department of Biology, Emory College of Arts and Sciences, Atlanta, GA 30322
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322
- Graduate Program in Biochemistry, Cell and Developmental Biology, Emory University, Atlanta, GA 30322
| | - Pranav S Yalamanchili
- Department of Biology, Emory College of Arts and Sciences, Atlanta, GA 30322
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322
| | - Jordan N Goldy
- Department of Biology, Emory College of Arts and Sciences, Atlanta, GA 30322
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322
- Graduate Program in Biochemistry, Cell and Developmental Biology, Emory University, Atlanta, GA 30322
| | - Sara W Leung
- Department of Biology, Emory College of Arts and Sciences, Atlanta, GA 30322
| | - Anita H Corbett
- Department of Biology, Emory College of Arts and Sciences, Atlanta, GA 30322
| | - Kenneth H Moberg
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322
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2
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The RhoGEF Trio: A Protein with a Wide Range of Functions in the Vascular Endothelium. Int J Mol Sci 2021; 22:ijms221810168. [PMID: 34576329 PMCID: PMC8467920 DOI: 10.3390/ijms221810168] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 09/16/2021] [Accepted: 09/17/2021] [Indexed: 12/29/2022] Open
Abstract
Many cellular processes are controlled by small GTPases, which can be activated by guanine nucleotide exchange factors (GEFs). The RhoGEF Trio contains two GEF domains that differentially activate the small GTPases such as Rac1/RhoG and RhoA. These small RhoGTPases are mainly involved in the remodeling of the actin cytoskeleton. In the endothelium, they regulate junctional stabilization and play a crucial role in angiogenesis and endothelial barrier integrity. Multiple extracellular signals originating from different vascular processes can influence the activity of Trio and thereby the regulation of the forementioned small GTPases and actin cytoskeleton. This review elucidates how various signals regulate Trio in a distinct manner, resulting in different functional outcomes that are crucial for endothelial cell function in response to inflammation.
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3
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Schultz-Rogers L, Muthusamy K, Pinto E Vairo F, Klee EW, Lanpher B. Novel loss-of-function variants in TRIO are associated with neurodevelopmental disorder: case report. BMC MEDICAL GENETICS 2020; 21:219. [PMID: 33167890 PMCID: PMC7654171 DOI: 10.1186/s12881-020-01159-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 10/28/2020] [Indexed: 01/24/2023]
Abstract
Background Damaging variants in TRIO have been associated with moderate to severe neurodevelopmental disorders in humans. While recent work has delineated the positional effect of missense variation on the resulting phenotype, the clinical spectrum associated with loss-of-function variation has yet to be fully defined. Case presentation We report on two probands with novel loss-of-function variants in TRIO. Patient 1 presents with a severe neurodevelopmental disorder and macrocephaly. The TRIO variant is inherited from his affected mother. Patient 2 presents with moderate developmental delays, microcephaly, and cutis aplasia with a frameshift variant of unknown inheritance. Conclusions We describe two patients with neurodevelopmental disorder, macro/microcephaly, and cutis aplasia in one patient. Both patients have loss-of-function variants, helping to further characterize how these types of variants affect the phenotypic spectrum associated with TRIO. We also present the third reported case of autosomal dominant inheritance of a damaging variant in TRIO.
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Affiliation(s)
| | | | - Filippo Pinto E Vairo
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA.,Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - Eric W Klee
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA.,Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - Brendan Lanpher
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA.
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4
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Paskus JD, Herring BE, Roche KW. Kalirin and Trio: RhoGEFs in Synaptic Transmission, Plasticity, and Complex Brain Disorders. Trends Neurosci 2020; 43:505-518. [PMID: 32513570 DOI: 10.1016/j.tins.2020.05.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 04/15/2020] [Accepted: 05/05/2020] [Indexed: 02/07/2023]
Abstract
Changes in the actin cytoskeleton are a primary mechanism mediating the morphological and functional plasticity that underlies learning and memory. The synaptic Ras homologous (Rho) guanine nucleotide exchange factors (GEFs) Kalirin and Trio have emerged as central regulators of actin dynamics at the synapse. The increased attention surrounding Kalirin and Trio stems from the growing evidence for their roles in the etiology of a wide range of neurodevelopmental and neurodegenerative disorders. In this Review, we discuss recent findings revealing the unique and diverse functions of these paralog proteins in neurodevelopment, excitatory synaptic transmission, and plasticity. We additionally survey the growing literature implicating these proteins in various neurological disorders.
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Affiliation(s)
- Jeremiah D Paskus
- Receptor Biology Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA.
| | - Bruce E Herring
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Katherine W Roche
- Receptor Biology Section, National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA.
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5
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Rho GTPase Regulators and Effectors in Autism Spectrum Disorders: Animal Models and Insights for Therapeutics. Cells 2020; 9:cells9040835. [PMID: 32244264 PMCID: PMC7226772 DOI: 10.3390/cells9040835] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/22/2020] [Accepted: 03/26/2020] [Indexed: 12/18/2022] Open
Abstract
The Rho family GTPases are small G proteins that act as molecular switches shuttling between active and inactive forms. Rho GTPases are regulated by two classes of regulatory proteins, guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Rho GTPases transduce the upstream signals to downstream effectors, thus regulating diverse cellular processes, such as growth, migration, adhesion, and differentiation. In particular, Rho GTPases play essential roles in regulating neuronal morphology and function. Recent evidence suggests that dysfunction of Rho GTPase signaling contributes substantially to the pathogenesis of autism spectrum disorder (ASD). It has been found that 20 genes encoding Rho GTPase regulators and effectors are listed as ASD risk genes by Simons foundation autism research initiative (SFARI). This review summarizes the clinical evidence, protein structure, and protein expression pattern of these 20 genes. Moreover, ASD-related behavioral phenotypes in animal models of these genes are reviewed, and the therapeutic approaches that show successful treatment effects in these animal models are discussed.
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6
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Tao T, Sun J, Peng Y, Li Y, Wang P, Chen X, Zhao W, Zheng YY, Wei L, Wang W, Zhou Y, Liu J, Shi YS, Zhu MS. Golgi-resident TRIO regulates membrane trafficking during neurite outgrowth. J Biol Chem 2019; 294:10954-10968. [PMID: 31152060 PMCID: PMC6635450 DOI: 10.1074/jbc.ra118.007318] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 05/21/2019] [Indexed: 11/06/2022] Open
Abstract
Neurite outgrowth requires coordinated cytoskeletal rearrangements in the growth cone and directional membrane delivery from the neuronal soma. As an essential Rho guanine nucleotide exchange factor (GEF), TRIO is necessary for cytoskeletal dynamics during neurite outgrowth, but its participation in the membrane delivery is unclear. Using co-localization studies, live-cell imaging, and fluorescence recovery after photobleaching analysis, along with neurite outgrowth assay and various biochemical approaches, we here report that in mouse cerebellar granule neurons, TRIO protein pools at the Golgi and regulates membrane trafficking by controlling the directional maintenance of both RAB8 (member RAS oncogene family 8)- and RAB10-positive membrane vesicles. We found that the spectrin repeats in Golgi-resident TRIO confer RAB8 and RAB10 activation by interacting with and activating the RAB GEF RABIN8. Constitutively active RAB8 or RAB10 could partially restore the neurite outgrowth of TRIO-deficient cerebellar granule neurons, suggesting that TRIO-regulated membrane trafficking has an important functional role in neurite outgrowth. Our results also suggest cross-talk between Rho GEF and Rab GEF in controlling both cytoskeletal dynamics and membrane trafficking during neuronal development. They further highlight how protein pools localized to specific organelles regulate crucial cellular activities and functions. In conclusion, our findings indicate that TRIO regulates membrane trafficking during neurite outgrowth in coordination with its GEF-dependent function in controlling cytoskeletal dynamics via Rho GTPases.
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Affiliation(s)
- Tao Tao
- Model Animal Research Center, State Key Laboratory of Pharmaceutical Biotechnology, Department of Neurology of the Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing University, Nanjing 210061, China and
| | - Jie Sun
- Model Animal Research Center, State Key Laboratory of Pharmaceutical Biotechnology, Department of Neurology of the Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing University, Nanjing 210061, China and
| | - Yajing Peng
- Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Yeqiong Li
- Model Animal Research Center, State Key Laboratory of Pharmaceutical Biotechnology, Department of Neurology of the Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing University, Nanjing 210061, China and
| | - Pei Wang
- Model Animal Research Center, State Key Laboratory of Pharmaceutical Biotechnology, Department of Neurology of the Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing University, Nanjing 210061, China and
| | - Xin Chen
- Model Animal Research Center, State Key Laboratory of Pharmaceutical Biotechnology, Department of Neurology of the Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing University, Nanjing 210061, China and
| | - Wei Zhao
- Model Animal Research Center, State Key Laboratory of Pharmaceutical Biotechnology, Department of Neurology of the Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing University, Nanjing 210061, China and
| | - Yan-Yan Zheng
- Model Animal Research Center, State Key Laboratory of Pharmaceutical Biotechnology, Department of Neurology of the Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing University, Nanjing 210061, China and
| | - Lisha Wei
- Model Animal Research Center, State Key Laboratory of Pharmaceutical Biotechnology, Department of Neurology of the Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing University, Nanjing 210061, China and
| | - Wei Wang
- Model Animal Research Center, State Key Laboratory of Pharmaceutical Biotechnology, Department of Neurology of the Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing University, Nanjing 210061, China and
| | - Yuwei Zhou
- Model Animal Research Center, State Key Laboratory of Pharmaceutical Biotechnology, Department of Neurology of the Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing University, Nanjing 210061, China and
| | - Jianghuai Liu
- Model Animal Research Center, State Key Laboratory of Pharmaceutical Biotechnology, Department of Neurology of the Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing University, Nanjing 210061, China and
| | - Yun Stone Shi
- Model Animal Research Center, State Key Laboratory of Pharmaceutical Biotechnology, Department of Neurology of the Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing University, Nanjing 210061, China and
| | - Min-Sheng Zhu
- Model Animal Research Center, State Key Laboratory of Pharmaceutical Biotechnology, Department of Neurology of the Affiliated Nanjing Drum Tower Hospital of Nanjing University Medical School, Nanjing University, Nanjing 210061, China and.
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7
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Tao T, Sun J, Peng Y, Wang P, Chen X, Zhao W, Li Y, Wei L, Wang W, Zheng Y, Wang Y, Zhang X, Zhu MS. Distinct functions of Trio GEF domains in axon outgrowth of cerebellar granule neurons. J Genet Genomics 2019; 46:87-96. [DOI: 10.1016/j.jgg.2019.02.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 01/14/2019] [Accepted: 02/19/2019] [Indexed: 10/27/2022]
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8
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Dufurrena Q, Bäck N, Mains R, Hodgson L, Tanowitz H, Mandela P, Eipper B, Kuliawat R. Kalirin/Trio Rho GDP/GTP exchange factors regulate proinsulin and insulin secretion. J Mol Endocrinol 2018; 62:JME-18-0048.R2. [PMID: 30407917 PMCID: PMC6494717 DOI: 10.1530/jme-18-0048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 11/05/2018] [Indexed: 12/31/2022]
Abstract
Key features for progression to pancreatic β-cell failure and disease are loss of glucose responsiveness and an increased ratio of secreted proinsulin to insulin. Proinsulin and insulin are stored in secretory granules (SGs) and the fine-tuning of hormone output requires signal mediated recruitment of select SG populations according to intracellular location and age. The GTPase Rac1 coordinates multiple signaling pathways that specify SG release and Rac1 activity is controlled in part by GDP/GTP exchange factors (GEFs). To explore the function of two large multidomain GEFs, Kalirin and Trio in β-cells, we manipulated their Rac1-specific GEF1 domain activity by using small molecule inhibitors and by genetically ablating Kalirin. We examined age related secretory granule behavior employing radiolabeling protocols. Loss of Kalirin/Trio function attenuated radioactive proinsulin release by reducing constitutive-like secretion and exocytosis of 2-hour old granules. At later chase times or at steady state, Kalirin/Trio manipulations decreased glucose stimulated insulin output. Finally, use of a Rac1 FRET biosensor with cultured β-cell lines, demonstrated that Kalirin/Trio GEF1 activity was required for normal rearrangement of Rac1 to the plasma membrane in response to glucose. Rac1 activation can be evoked by both glucose metabolism and signaling through the incretin glucagon-like peptide 1 (GLP-1) receptor. GLP-1 addition restored Rac1 localization/activity and insulin secretion in the absence of Kalirin, thereby assigning Kalirin's participation to stimulatory glucose signaling.
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Affiliation(s)
- Quinn Dufurrena
- Department of Medicine, Stony Brook University School of Medicine, Stony Brook, NY
| | - Nils Bäck
- Department of Anatomy, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Richard Mains
- Department of Neuroscience, University of Connecticut Health Center, Farmington, CT
| | - Louis Hodgson
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY
| | - Herbert Tanowitz
- Departments of Pathology, Medicine, Albert Einstein College of Medicine, Bronx, NY
| | | | - Betty Eipper
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT
| | - Regina Kuliawat
- Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY
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9
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Backer S, Lokmane L, Landragin C, Deck M, Garel S, Bloch-Gallego E. Trio GEF mediates RhoA activation downstream of Slit2 and coordinates telencephalic wiring. Development 2018; 145:dev.153692. [PMID: 30177526 DOI: 10.1242/dev.153692] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 08/24/2018] [Indexed: 01/01/2023]
Abstract
Trio, a member of the Dbl family of guanine nucleotide exchange factors, activates Rac1 downstream of netrin 1/DCC signalling in axon outgrowth and guidance. Although it has been proposed that Trio also activates RhoA, the putative upstream factors remain unknown. Here, we show that Slit2 induces Trio-dependent RhoA activation, revealing a crosstalk between Slit and Trio/RhoA signalling. Consistently, we found that RhoA activity is hindered in vivo in T rio mutant mouse embryos. We next studied the development of the ventral telencephalon and thalamocortical axons, which have been previously shown to be controlled by Slit2. Remarkably, this analysis revealed that Trio knockout (KO) mice show phenotypes that bear strong similarities to the ones that have been reported in Slit2 KO mice in both guidepost corridor cells and thalamocortical axon pathfinding in the ventral telencephalon. Taken together, our results show that Trio induces RhoA activation downstream of Slit2, and support a functional role in ensuring the proper positioning of both guidepost cells and a major axonal tract. Our study indicates a novel role for Trio in Slit2 signalling and forebrain wiring, highlighting its role in multiple guidance pathways as well as in biological functions of importance for a factor involved in human brain disorders.
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Affiliation(s)
- Stéphanie Backer
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, 75014 Paris, France.,INSERM, U1016, Department of Development, Reproduction and Cancer, 24 rue du Faubourg Saint-Jacques, 75014 Paris, France
| | - Ludmilla Lokmane
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS UMR8197, INSERM U1024, PSL research University, 75005 Paris, France
| | - Camille Landragin
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, 75014 Paris, France.,INSERM, U1016, Department of Development, Reproduction and Cancer, 24 rue du Faubourg Saint-Jacques, 75014 Paris, France
| | - Marie Deck
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS UMR8197, INSERM U1024, PSL research University, 75005 Paris, France
| | - Sonia Garel
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS UMR8197, INSERM U1024, PSL research University, 75005 Paris, France
| | - Evelyne Bloch-Gallego
- Institut Cochin, Université Paris Descartes, CNRS UMR 8104, 75014 Paris, France .,INSERM, U1016, Department of Development, Reproduction and Cancer, 24 rue du Faubourg Saint-Jacques, 75014 Paris, France
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10
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Rho GTPases in Intellectual Disability: From Genetics to Therapeutic Opportunities. Int J Mol Sci 2018; 19:ijms19061821. [PMID: 29925821 PMCID: PMC6032284 DOI: 10.3390/ijms19061821] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 06/14/2018] [Accepted: 06/16/2018] [Indexed: 12/22/2022] Open
Abstract
Rho-class small GTPases are implicated in basic cellular processes at nearly all brain developmental steps, from neurogenesis and migration to axon guidance and synaptic plasticity. GTPases are key signal transducing enzymes that link extracellular cues to the neuronal responses required for the construction of neuronal networks, as well as for synaptic function and plasticity. Rho GTPases are highly regulated by a complex set of activating (GEFs) and inactivating (GAPs) partners, via protein:protein interactions (PPI). Misregulated RhoA, Rac1/Rac3 and cdc42 activity has been linked with intellectual disability (ID) and other neurodevelopmental conditions that comprise ID. All genetic evidences indicate that in these disorders the RhoA pathway is hyperactive while the Rac1 and cdc42 pathways are consistently hypoactive. Adopting cultured neurons for in vitro testing and specific animal models of ID for in vivo examination, the endophenotypes associated with these conditions are emerging and include altered neuronal networking, unbalanced excitation/inhibition and altered synaptic activity and plasticity. As we approach a clearer definition of these phenotype(s) and the role of hyper- and hypo-active GTPases in the construction of neuronal networks, there is an increasing possibility that selective inhibitors and activators might be designed via PPI, or identified by screening, that counteract the misregulation of small GTPases and result in alleviation of the cognitive condition. Here we review all knowledge in support of this possibility.
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11
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Katrancha SM, Wu Y, Zhu M, Eipper BA, Koleske AJ, Mains RE. Neurodevelopmental disease-associated de novo mutations and rare sequence variants affect TRIO GDP/GTP exchange factor activity. Hum Mol Genet 2017; 26:4728-4740. [PMID: 28973398 PMCID: PMC5886096 DOI: 10.1093/hmg/ddx355] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Revised: 08/07/2017] [Accepted: 08/22/2017] [Indexed: 12/19/2022] Open
Abstract
Bipolar disorder, schizophrenia, autism and intellectual disability are complex neurodevelopmental disorders, debilitating millions of people. Therapeutic progress is limited by poor understanding of underlying molecular pathways. Using a targeted search, we identified an enrichment of de novo mutations in the gene encoding the 330-kDa triple functional domain (TRIO) protein associated with neurodevelopmental disorders. By generating multiple TRIO antibodies, we show that the smaller TRIO9 isoform is the major brain protein product, and its levels decrease after birth. TRIO9 contains two guanine nucleotide exchange factor (GEF) domains with distinct specificities: GEF1 activates both Rac1 and RhoG; GEF2 activates RhoA. To understand the impact of disease-associated de novo mutations and other rare sequence variants on TRIO function, we utilized two FRET-based biosensors: a Rac1 biosensor to study mutations in TRIO (T)GEF1, and a RhoA biosensor to study mutations in TGEF2. We discovered that one autism-associated de novo mutation in TGEF1 (K1431M), at the TGEF1/Rac1 interface, markedly decreased its overall activity toward Rac1. A schizophrenia-associated rare sequence variant in TGEF1 (F1538Intron) was substantially less active, normalized to protein level and expressed poorly. Overall, mutations in TGEF1 decreased GEF1 activity toward Rac1. One bipolar disorder-associated rare variant (M2145T) in TGEF2 impaired inhibition by the TGEF2 pleckstrin-homology domain, resulting in dramatically increased TGEF2 activity. Overall, genetic damage to both TGEF domains altered TRIO catalytic activity, decreasing TGEF1 activity and increasing TGEF2 activity. Importantly, both GEF changes are expected to decrease neurite outgrowth, perhaps consistent with their association with neurodevelopmental disorders.
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Affiliation(s)
- Sara M Katrancha
- Interdepartmental Neuroscience Program
- Department of Neuroscience
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Yi Wu
- Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, CT, USA
| | - Minsheng Zhu
- Model Animal Research Center, Nanjing University, Nanjing 210061, China
| | - Betty A Eipper
- Department of Neuroscience
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT, USA
| | - Anthony J Koleske
- Interdepartmental Neuroscience Program
- Department of Neuroscience
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
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12
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Goedhart J, van Unen J. Molecular perturbation strategies to examine spatiotemporal features of Rho GEF and Rho GTPase activity in living cells. Small GTPases 2017; 10:178-186. [PMID: 28521592 PMCID: PMC6548299 DOI: 10.1080/21541248.2017.1302551] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Much of our current knowledge of Rho GTPase networks and the regulation by Rho guanine exchange factors (Rho GEFs) and Rho GTPase activating proteins (Rho GAPs) is based on population-based techniques. Over the last decades, technologies that enable single cell analysis with high spatial and temporal resolution have revealed that Rho GTPase activity in cells is regulated on second timescales and at submicrometer length scales. Therefore, perturbation methods with matching spatial and temporal resolution are crucial to further our understanding of Rho GTPase signaling. Here, we give a brief overview of the components of Rho GTPase signaling networks and review a range of existing perturbation strategies that target a specific component of the Rho GTPase signaling module. The advantages and limitations of each perturbation method are discussed. Several recommendations are formulated to guide future studies aimed at addressing spatiotemporal aspects of Rho GEF and Rho GTPase signaling.
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Affiliation(s)
- Joachim Goedhart
- a Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam , Amsterdam , The Netherlands
| | - Jakobus van Unen
- a Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam , Amsterdam , The Netherlands
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13
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Terry-Lorenzo RT, Torres VI, Wagh D, Galaz J, Swanson SK, Florens L, Washburn MP, Waites CL, Gundelfinger ED, Reimer RJ, Garner CC. Trio, a Rho Family GEF, Interacts with the Presynaptic Active Zone Proteins Piccolo and Bassoon. PLoS One 2016; 11:e0167535. [PMID: 27907191 PMCID: PMC5132261 DOI: 10.1371/journal.pone.0167535] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 11/15/2016] [Indexed: 12/17/2022] Open
Abstract
Synaptic vesicles (SVs) fuse with the plasma membrane at a precise location called the presynaptic active zone (AZ). This fusion is coordinated by proteins embedded within a cytoskeletal matrix assembled at the AZ (CAZ). In the present study, we have identified a novel binding partner for the CAZ proteins Piccolo and Bassoon. This interacting protein, Trio, is a member of the Dbl family of guanine nucleotide exchange factors (GEFs) known to regulate the dynamic assembly of actin and growth factor dependent axon guidance and synaptic growth. Trio was found to interact with the C-terminal PBH 9/10 domains of Piccolo and Bassoon via its own N-terminal Spectrin repeats, a domain that is also critical for its localization to the CAZ. Moreover, our data suggest that regions within the C-terminus of Trio negatively regulate its interactions with Piccolo/Bassoon. These findings provide a mechanism for the presynaptic targeting of Trio and support a model in which Piccolo and Bassoon play a role in regulating neurotransmission through interactions with proteins, including Trio, that modulate the dynamic assembly of F-actin during cycles of synaptic vesicle exo- and endocytosis.
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Affiliation(s)
- Ryan T. Terry-Lorenzo
- Dept. of Psychiatry and Behavioral Science, Nancy Pritzker Laboratory, Stanford University, Palo Alto, California, United States of America
| | - Viviana I. Torres
- Dept. of Psychiatry and Behavioral Science, Nancy Pritzker Laboratory, Stanford University, Palo Alto, California, United States of America
- Centro de Envejecimiento y Regeneración (CARE), Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile, Alameda, Santiago, Chile
| | - Dhananjay Wagh
- Dept. of Psychiatry and Behavioral Science, Nancy Pritzker Laboratory, Stanford University, Palo Alto, California, United States of America
| | - Jose Galaz
- Dept. of Psychiatry and Behavioral Science, Nancy Pritzker Laboratory, Stanford University, Palo Alto, California, United States of America
| | - Selene K. Swanson
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Laurence Florens
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Michael P. Washburn
- Stowers Institute for Medical Research, Kansas City, Missouri, United States of America
| | - Clarissa L. Waites
- Dept. of Psychiatry and Behavioral Science, Nancy Pritzker Laboratory, Stanford University, Palo Alto, California, United States of America
| | - Eckart D. Gundelfinger
- Dept. of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Richard J. Reimer
- Dept. of Neurology and Neurological Sciences Stanford University and Veterans Affairs Palo Alto Health Care System, Palo Alto, California, United States of America
| | - Craig C. Garner
- Dept. of Psychiatry and Behavioral Science, Nancy Pritzker Laboratory, Stanford University, Palo Alto, California, United States of America
- German Centers for Neurodegenerative Diseases, Charité - Medical University, Berlin, Germany
- * E-mail:
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14
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Delespaul L, Lesluyes T, Pérot G, Brulard C, Lartigue L, Baud J, Lagarde P, Le Guellec S, Neuville A, Terrier P, Vince-Ranchère D, Schmidt S, Debant A, Coindre JM, Chibon F. Recurrent TRIO Fusion in Nontranslocation–Related Sarcomas. Clin Cancer Res 2016; 23:857-867. [DOI: 10.1158/1078-0432.ccr-16-0290] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 06/27/2016] [Accepted: 07/27/2016] [Indexed: 11/16/2022]
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15
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Pengelly RJ, Greville-Heygate S, Schmidt S, Seaby EG, Jabalameli MR, Mehta SG, Parker MJ, Goudie D, Fagotto-Kaufmann C, Mercer C, Debant A, Ennis S, Baralle D. Mutations specific to the Rac-GEF domain of TRIO cause intellectual disability and microcephaly. J Med Genet 2016; 53:735-742. [PMID: 27418539 PMCID: PMC5264232 DOI: 10.1136/jmedgenet-2016-103942] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 06/21/2016] [Accepted: 06/23/2016] [Indexed: 11/03/2022]
Abstract
BACKGROUND Neurodevelopmental disorders have challenged clinical genetics for decades, with over 700 genes implicated and many whose function remains unknown. The application of whole-exome sequencing is proving pivotal in closing the genotype/phenotype gap through the discovery of new genes and variants that help to unravel the pathogenic mechanisms driving neuropathogenesis. One such discovery includes TRIO, a gene recently implicated in neurodevelopmental delay. Trio is a Dbl family guanine nucleotide exchange factor (GEF) and a major regulator of neuronal development, controlling actin cytoskeleton dynamics by activating the GTPase Rac1. METHODS Whole-exome sequencing was undertaken on a family presenting with global developmental delay, microcephaly and mild dysmorphism. Father/daughter exome analysis was performed, followed by confirmatory Sanger sequencing and segregation analysis on four individuals. Three further patients were recruited through the deciphering developmental disorders (DDD) study. Functional studies were undertaken using patient-specific Trio protein mutations. RESULTS We identified a frameshift deletion in TRIO that segregated autosomal dominantly. By scrutinising data from DDD, we further identified three unrelated children with a similar phenotype who harboured de novo missense mutations in TRIO. Biochemical studies demonstrated that in three out of four families, the Trio mutations led to a markedly reduced Rac1 activation. CONCLUSIONS We describe an inherited global developmental delay phenotype associated with a frameshift deletion in TRIO. Additionally, we identify pathogenic de novo missense mutations in TRIO associated with the same consistent phenotype, intellectual disability, microcephaly and dysmorphism with striking digital features. We further functionally validate the importance of the GEF domain in Trio protein function. Our study demonstrates how genomic technologies are yet again proving prolific in diagnosing and advancing the understanding of neurodevelopmental disorders.
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Affiliation(s)
- Reuben J Pengelly
- Department of Human Genetics and Genomic Medicine, Faculty of Medicine, University of Southampton, Southampton, UK
| | | | - Susanne Schmidt
- Centre de Recherche en Biologie Cellulaire de Montpellier, Centre National de la Recherche Scientifique, Université de Montpellier, Montpellier, Cédex, France
| | - Eleanor G Seaby
- Department of Human Genetics and Genomic Medicine, Faculty of Medicine, University of Southampton, Southampton, UK
| | - M Reza Jabalameli
- Department of Human Genetics and Genomic Medicine, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Sarju G Mehta
- Department of Clinical Genetics, Cambridge University Hospital Trust, Cambridge, UK
| | - Michael J Parker
- Sheffield Clinical Genetics Service, Sheffield Children's Hospital NHS Foundation Trust, OPD2, Northern General Hospital, Sheffield, UK
| | - David Goudie
- Department of Clinical Genetics, Ninewells Hospital, Dundee, UK
| | - Christine Fagotto-Kaufmann
- Centre de Recherche en Biologie Cellulaire de Montpellier, Centre National de la Recherche Scientifique, Université de Montpellier, Montpellier, Cédex, France
| | - Catherine Mercer
- Wessex Clinical Genetics Service, Princess Anne Hospital, Southampton, UK
| | | | - Anne Debant
- Centre de Recherche en Biologie Cellulaire de Montpellier, Centre National de la Recherche Scientifique, Université de Montpellier, Montpellier, Cédex, France
| | - Sarah Ennis
- Department of Human Genetics and Genomic Medicine, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Diana Baralle
- Wessex Clinical Genetics Service, Princess Anne Hospital, Southampton, UK
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16
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Kalirin and Trio proteins serve critical roles in excitatory synaptic transmission and LTP. Proc Natl Acad Sci U S A 2016; 113:2264-9. [PMID: 26858404 DOI: 10.1073/pnas.1600179113] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The molecular mechanism underlying long-term potentiation (LTP) is critical for understanding learning and memory. CaMKII, a key kinase involved in LTP, is both necessary and sufficient for LTP induction. However, how CaMKII gives rise to LTP is currently unknown. Recent studies suggest that Rho GTPases are necessary for LTP. Rho GTPases are activated by Rho guanine exchange factors (RhoGEFs), but the RhoGEF(s) required for LTP also remain unknown. Here, using a combination of molecular, electrophysiological, and imaging techniques, we show that the RhoGEF Kalirin and its paralog Trio play critical and redundant roles in excitatory synapse structure and function. Furthermore, we show that CaMKII phosphorylation of Kalirin is sufficient to enhance synaptic AMPA receptor expression, and that preventing CaMKII signaling through Kalirin and Trio prevents LTP induction. Thus, our data identify Kalirin and Trio as the elusive targets of CaMKII phosphorylation responsible for AMPA receptor up-regulation during LTP.
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17
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DeGeer J, Kaplan A, Mattar P, Morabito M, Stochaj U, Kennedy TE, Debant A, Cayouette M, Fournier AE, Lamarche-Vane N. Hsc70 chaperone activity underlies Trio GEF function in axon growth and guidance induced by netrin-1. J Cell Biol 2015; 210:817-32. [PMID: 26323693 PMCID: PMC4555821 DOI: 10.1083/jcb.201505084] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
During development, netrin-1 is both an attractive and repulsive axon guidance cue and mediates its attractive function through the receptor Deleted in Colorectal Cancer (DCC). The activation of Rho guanosine triphosphatases within the extending growth cone facilitates the dynamic reorganization of the cytoskeleton required to drive axon extension. The Rac1 guanine nucleotide exchange factor (GEF) Trio is essential for netrin-1-induced axon outgrowth and guidance. Here, we identify the molecular chaperone heat shock cognate protein 70 (Hsc70) as a novel Trio regulator. Hsc70 dynamically associated with the N-terminal region and Rac1 GEF domain of Trio. Whereas Hsc70 expression supported Trio-dependent Rac1 activation, adenosine triphosphatase-deficient Hsc70 (D10N) abrogated Trio Rac1 GEF activity and netrin-1-induced Rac1 activation. Hsc70 was required for netrin-1-mediated axon growth and attraction in vitro, whereas Hsc70 activity supported callosal projections and radial neuronal migration in the embryonic neocortex. These findings demonstrate that Hsc70 chaperone activity is required for Rac1 activation by Trio and this function underlies netrin-1/DCC-dependent axon outgrowth and guidance.
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Affiliation(s)
- Jonathan DeGeer
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada The Research Institute of McGill University Health Centre, Montreal, Quebec H4A 3J1, Canada
| | - Andrew Kaplan
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Pierre Mattar
- Cellular Neurobiology Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, Quebec H2W 1R7, Canada
| | - Morgane Morabito
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada The Research Institute of McGill University Health Centre, Montreal, Quebec H4A 3J1, Canada
| | - Ursula Stochaj
- Department of Physiology, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Timothy E Kennedy
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Anne Debant
- Centre de Recherche de Biochimie Macromoléculaire, Centre National de la Recherche Scientifique, UMR5237, University of Montpellier, Montpellier 34293, France
| | - Michel Cayouette
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada Cellular Neurobiology Research Unit, Institut de Recherches Cliniques de Montréal, Montreal, Quebec H2W 1R7, Canada Department of Medicine, Université de Montréal, Montreal, Quubec H3T 1J4, Canada
| | - Alyson E Fournier
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Nathalie Lamarche-Vane
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec H3A 0C7, Canada The Research Institute of McGill University Health Centre, Montreal, Quebec H4A 3J1, Canada
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18
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Regulating Rac in the nervous system: molecular function and disease implication of Rac GEFs and GAPs. BIOMED RESEARCH INTERNATIONAL 2015; 2015:632450. [PMID: 25879033 PMCID: PMC4388020 DOI: 10.1155/2015/632450] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 03/06/2015] [Indexed: 12/11/2022]
Abstract
Rho family GTPases, including RhoA, Rac1, and Cdc42 as the most studied members, are master regulators of actin cytoskeletal organization. Rho GTPases control various aspects of the nervous system and are associated with a number of neuropsychiatric and neurodegenerative diseases. The activity of Rho GTPases is controlled by two families of regulators, guanine nucleotide exchange factors (GEFs) as the activators and GTPase-activating proteins (GAPs) as the inhibitors. Through coordinated regulation by GEFs and GAPs, Rho GTPases act as converging signaling molecules that convey different upstream signals in the nervous system. So far, more than 70 members of either GEFs or GAPs of Rho GTPases have been identified in mammals, but only a small subset of them have well-known functions. Thus, characterization of important GEFs and GAPs in the nervous system is crucial for the understanding of spatiotemporal dynamics of Rho GTPase activity in different neuronal functions. In this review, we summarize the current understanding of GEFs and GAPs for Rac1, with emphasis on the molecular function and disease implication of these regulators in the nervous system.
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Silencing of PNPLA6, the neuropathy target esterase (NTE) codifying gene, alters neurodifferentiation of human embryonal carcinoma stem cells (NT2). Neuroscience 2014; 281:54-67. [DOI: 10.1016/j.neuroscience.2014.08.031] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 08/18/2014] [Accepted: 08/19/2014] [Indexed: 12/30/2022]
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20
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Mulinari S, Häcker U. Rho-guanine nucleotide exchange factors during development: Force is nothing without control. Small GTPases 2014; 1:28-43. [PMID: 21686118 DOI: 10.4161/sgtp.1.1.12672] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2010] [Revised: 05/31/2010] [Accepted: 06/14/2010] [Indexed: 01/04/2023] Open
Abstract
The development of multicellular organisms is associated with extensive rearrangements of tissues and cell sheets. The driving force for these rearrangements is generated mostly by the actin cytoskeleton. In order to permit the reproducible development of a specific body plan, dynamic reorganization of the actin cytoskeleton must be precisely coordinated in space and time. GTP-exchange factors that activate small GTPases of the Rho family play an important role in this process. Here we review the role of this class of cytoskeletal regulators during important developmental processes such as epithelial morphogenesis, cytokinesis, cell migration, cell polarity, neuronal growth cone extension and phagocytosis in different model systems.
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Affiliation(s)
- Shai Mulinari
- Department of Experimental Medical Science; Lund Strategic Research Center for Stem Cell Biology and Cell Therapy; Lund University; Lund, Sweden
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21
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Schmidt S, Debant A. Function and regulation of the Rho guanine nucleotide exchange factor Trio. Small GTPases 2014; 5:e29769. [PMID: 24987837 DOI: 10.4161/sgtp.29769] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Rho GTPases oscillate between an inactive GDP-bound state and an active GTP-bound state. They are activated by Rho Guanine nucleotide Exchange Factors (GEF), which accelerate the GDP to GTP exchange. RhoGEFs fall into two different classes: the Dbl family and the DOCK family of proteins. In this review, we focus on the function and regulation of the Dbl family RhoGEF Trio. Trio and its paralog Kalirin are unique within this family in that they display two GEF domains of distinct specificity. Trio is a major regulator of neuronal development, and its function is conserved through evolution. Moreover, Trio plays an important role in cell adhesion and in signaling pathways elicited by Gαq protein-coupled receptors. Combined, these observations suggest that Trio has a major role in cellular physiology. Of note, Trio is an essential gene for mouse development, with a prominent role in the development of the nervous system. Finally, Trio expression is significantly increased in different types of tumors and it has been proposed that it could participate in oncogenesis.
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Affiliation(s)
- Susanne Schmidt
- Centre de Recherche en Biochimie Macromoléculaire; CNRS - UMR 5237; Université de Montpellier; Montpellier, France
| | - Anne Debant
- Centre de Recherche en Biochimie Macromoléculaire; CNRS - UMR 5237; Université de Montpellier; Montpellier, France
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22
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Abstract
Small G proteins of the Rho family and their activators the guanine nucleotide exchange factors (RhoGEFs) regulate essential cellular functions and their deregulation has been associated with an amazing variety of human disorders, including cancer, inflammation, vascular diseases, and mental retardation. Rho GTPases and RhoGEFs therefore represent important targets for inhibition, not only in basic research but also for therapeutic purposes, and strategies to inhibit their function are actively being sought. Our lab has been very active in this field and has used the peptide aptamer technology to develop the first RhoGEF inhibitor, using the RhoGEF Trio as a model. Trio function has been described mainly in cell motility and axon growth in the nervous system via Rac1 GTPase activation, but recent findings suggest it to play also a role in the aggressive phenotype of various cancers, making it an attractive target for drug discovery. The object of this chapter is to demonstrate that targeting a RhoGEF using the peptide aptamer technology represents a valid and efficient approach to inhibit cellular processes in which Rho GTPase activity is upregulated. This is illustrated here by the first description of a peptide inhibitor of the oncogenic RhoGEF Tgat, TRIP(E32G), which is functional in vivo. On a long-term perspective, these peptide inhibitors can also serve as therapeutic tools or as guides for the discovery of small-molecule drugs, using an aptamer displacement screen.
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Affiliation(s)
- Susanne Schmidt
- Centre de Recherche en Biochimie Macromoléculaire, CNRS-UMR 5237, Universités Montpellier I et II, 1919 Route de Mende, Montpellier, France.
| | - Anne Debant
- Centre de Recherche en Biochimie Macromoléculaire, CNRS-UMR 5237, Universités Montpellier I et II, 1919 Route de Mende, Montpellier, France.
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23
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Tyrosine phosphorylation of the Rho guanine nucleotide exchange factor Trio regulates netrin-1/DCC-mediated cortical axon outgrowth. Mol Cell Biol 2012; 33:739-51. [PMID: 23230270 DOI: 10.1128/mcb.01264-12] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The chemotropic guidance cue netrin-1 mediates attraction of migrating axons during central nervous system development through the receptor Deleted in Colorectal Cancer (DCC). Downstream of netrin-1, activated Rho GTPases Rac1 and Cdc42 induce cytoskeletal rearrangements within the growth cone. The Rho guanine nucleotide exchange factor (GEF) Trio is essential for Rac1 activation downstream of netrin-1/DCC, but the molecular mechanisms governing Trio activity remain elusive. Here, we demonstrate that Trio is phosphorylated by Src family kinases in the embryonic rat cortex in response to netrin-1. In vitro, Trio was predominantly phosphorylated at Tyr(2622) by the Src kinase Fyn. Though the phospho-null mutant Trio(Y2622F) retained GEF activity toward Rac1, its expression impaired netrin-1-induced Rac1 activation and DCC-mediated neurite outgrowth in N1E-115 neuroblastoma cells. Trio(Y2622F) impaired netrin-1-induced axonal extension in cultured cortical neurons and was unable to colocalize with DCC in growth cones, in contrast to wild-type Trio. Furthermore, depletion of Trio in cortical neurons reduced the level of cell surface DCC in growth cones, which could be restored by expression of wild-type Trio but not Trio(Y2622F). Together, these findings demonstrate that Trio(Y2622) phosphorylation is essential for the regulation of the DCC/Trio signaling complex in cortical neurons during netrin-1-mediated axon outgrowth.
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Abstract
Small Rho-GTPases are enzymes that are bound to GDP or GTP, which determines their inactive or active state, respectively. The exchange of GDP for GTP is catalyzed by so-called Rho-guanine nucleotide exchange factors (GEFs). Rho-GEFs are characterized by a Dbl-homology (DH) and adjacent Pleckstrin-homology (PH) domain that serves as enzymatic unit for the GDP/GTP exchange. Rho-GEFs show different GTPase specificities, meaning that a particular GEF can activate either multiple GTPases or only one specific GTPase. We recently reported that the Rho-GEF Trio, known to be able to exchange GTP on Rac1, RhoG and RhoA, regulates lamellipodia formation to mediate cell spreading and migration in a Rac1-dependent manner. In this commentary, we review the current knowledge of Trio in several aspects of cell biology.
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Affiliation(s)
- Jos van Rijssel
- Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
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25
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Gonzalez-Billault C, Muñoz-Llancao P, Henriquez DR, Wojnacki J, Conde C, Caceres A. The role of small GTPases in neuronal morphogenesis and polarity. Cytoskeleton (Hoboken) 2012; 69:464-85. [PMID: 22605667 DOI: 10.1002/cm.21034] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Revised: 04/12/2012] [Accepted: 04/16/2012] [Indexed: 12/21/2022]
Abstract
The highly dynamic remodeling and cross talk of the microtubule and actin cytoskeleton support neuronal morphogenesis. Small RhoGTPases family members have emerged as crucial regulators of cytoskeletal dynamics. In this review we will comprehensively analyze findings that support the participation of RhoA, Rac, Cdc42, and TC10 in different neuronal morphogenetic events ranging from migration to synaptic plasticity. We will specifically address the contribution of these GTPases to support neuronal polarity and axonal elongation.
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Affiliation(s)
- Christian Gonzalez-Billault
- Faculty of Sciences, Laboratory of Cell and Neuronal Dynamics, Department of Biology and Institute for Cell Dynamics and Biotechnology, Universidad de Chile, Santiago, Chile.
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26
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Lee JW, Yeo SG, Kang BH, Lee HK, Kim JW, Lee SH, Kim KS, Cheon DS. Echovirus 30 induced neuronal cell death through TRIO-RhoA signaling activation. PLoS One 2012; 7:e36656. [PMID: 22586486 PMCID: PMC3346726 DOI: 10.1371/journal.pone.0036656] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 04/05/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Echovirus 30 (Echo30) is one of the most frequently identified human enteroviruses (EVs) causing aseptic meningitis and encephalitis. However the mechanism underlying the pathogenesis of Echo30 infection with significant clinical outcomes is not completely understood. The aim of this investigation is to illustrate molecular pathologic alteration in neuronal cells induced by Echo30 infection using clinical isolate from young patient with neurologic involvement. METHODOLOGY/PRINCIPAL FINDINGS To characterize the neuronal cellular response to Echo30 infection, we performed a proteomic analysis based on two-dimensional gel electrophoresis (2-DE) and MALDI-TOF/TOF Mass Spectrophotometric (MS) analysis. We identified significant alteration of several protein expression levels in Echo30-infected SK-N-SH cells. Among these proteins, we focused on an outstanding up-regulation of Triple functional domain (TRIO) in Echo30-infected SK-N-SH cells. Generally, TRIO acts as a key component in the regulation of axon guidance and cell migration. In this study, we determined that TRIO plays a role in the novel pathways in Echo30 induced neuronal cell death. CONCLUSIONS/SIGNIFICANCE Our finding shows that TRIO plays a critical role in neuronal cell death by Echo30 infection. Echo30 infection activates TRIO-guanine nucleotide exchange factor (GEF) domains (GEFD2) and RhoA signaling in turn. These results suggest that Echo30 infection induced neuronal cell death by activation of the TRIO-RhoA signaling. We expect the regulation of TRIO-RhoA signaling may represent a new therapeutic approach in treating aseptic meningitis and encephalitis induced by Echo30.
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Affiliation(s)
- June-Woo Lee
- Division of Enteric and Hepatitis Viruses, Center for Infectious Diseases, National Institutes of Health, Osong, Korea
| | - Sang-Gu Yeo
- Division of Enteric and Hepatitis Viruses, Center for Infectious Diseases, National Institutes of Health, Osong, Korea
| | - Byung-Hak Kang
- Division of Enteric and Hepatitis Viruses, Center for Infectious Diseases, National Institutes of Health, Osong, Korea
| | - Hoe-Kyu Lee
- Division of Enteric and Hepatitis Viruses, Center for Infectious Diseases, National Institutes of Health, Osong, Korea
| | - Jin-Won Kim
- Division of Enteric and Hepatitis Viruses, Center for Infectious Diseases, National Institutes of Health, Osong, Korea
| | - Sun-Hwa Lee
- Division of Enteric and Hepatitis Viruses, Center for Infectious Diseases, National Institutes of Health, Osong, Korea
| | - Ki-Sang Kim
- Division of Enteric and Hepatitis Viruses, Center for Infectious Diseases, National Institutes of Health, Osong, Korea
| | - Doo-Sung Cheon
- Division of Enteric and Hepatitis Viruses, Center for Infectious Diseases, National Institutes of Health, Osong, Korea
- * E-mail:
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27
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Lin L, Tran T, Hu S, Cramer T, Komuniecki R, Steven RM. RHGF-2 is an essential Rho-1 specific RhoGEF that binds to the multi-PDZ domain scaffold protein MPZ-1 in Caenorhabditis elegans. PLoS One 2012; 7:e31499. [PMID: 22363657 PMCID: PMC3282746 DOI: 10.1371/journal.pone.0031499] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Accepted: 01/12/2012] [Indexed: 11/18/2022] Open
Abstract
RhoGEF proteins activate the Rho family of small GTPases and thus play a key role in regulating fundamental cellular processes such as cell morphology and polarity, cell cycle progression and gene transcription. We identified a Caenorhabditis elegans RhoGEF protein, RHGF-2, as a binding partner of the C. elegans multi-PDZ domain scaffold protein MPZ-1 (MUPP1 in mammals). RHGF-2 exhibits significant identity to the mammalian RhoGEFs PLEKHG5/Tech/Syx and contains a class I C-terminal PDZ binding motif (SDV) that interacts most strongly to MPZ-1 PDZ domain eight. RHGF-2 RhoGEF activity is specific to the C. elegans RhoA homolog RHO-1 as determined by direct binding, GDP/GTP exchange and serum response element-driven reporter activity. rhgf-2 is an essential gene since rhgf-2 deletion mutants do not elongate during embryogenesis and hatch as short immobile animals that arrest development. Interestingly, the expression of a functional rhgf-2::gfp transgene appears to be exclusively neuronal and rhgf-2 overexpression results in loopy movement with exaggerated body bends. Transient expression of RHGF-2 in N1E-115 neuroblastoma cells prevents neurite outgrowth similar to constitutive RhoA activation in these cells. Together, these observations indicate neuronally expressed RHGF-2 is an essential RHO-1 specific RhoGEF that binds most strongly to MPZ-1 PDZ domain eight and is required for wild-type C. elegans morphology and growth.
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Affiliation(s)
- Li Lin
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
| | - Thuy Tran
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
| | - Shuang Hu
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
| | - Todd Cramer
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
| | - Richard Komuniecki
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
| | - Robert M. Steven
- Department of Biological Sciences, University of Toledo, Toledo, Ohio, United States of America
- * E-mail:
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Nile AH, Bankaitis VA, Grabon A. Mammalian diseases of phosphatidylinositol transfer proteins and their homologs. CLINICAL LIPIDOLOGY 2010; 5:867-897. [PMID: 21603057 PMCID: PMC3097519 DOI: 10.2217/clp.10.67] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Inositol and phosphoinositide signaling pathways represent major regulatory systems in eukaryotes. The physiological importance of these pathways is amply demonstrated by the variety of diseases that involve derangements in individual steps in inositide and phosphoinositide production and degradation. These diseases include numerous cancers, lipodystrophies and neurological syndromes. Phosphatidylinositol transfer proteins (PITPs) are emerging as fascinating regulators of phosphoinositide metabolism. Recent advances identify PITPs (and PITP-like proteins) to be coincidence detectors, which spatially and temporally coordinate the activities of diverse aspects of the cellular lipid metabolome with phosphoinositide signaling. These insights are providing new ideas regarding mechanisms of inherited mammalian diseases associated with derangements in the activities of PITPs and PITP-like proteins.
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Affiliation(s)
- Aaron H Nile
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-27090, USA
| | - Vytas A Bankaitis
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-27090, USA
| | - Aby Grabon
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-27090, USA
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Trio mediates netrin-1-induced Rac1 activation in axon outgrowth and guidance. Mol Cell Biol 2008; 28:2314-23. [PMID: 18212043 DOI: 10.1128/mcb.00998-07] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The chemotropic guidance cue netrin-1 promotes neurite outgrowth through its receptor Deleted in Colorectal Cancer (DCC) via activation of Rac1. The guanine nucleotide exchange factor (GEF) linking netrin-1/DCC to Rac1 activation has not yet been identified. Here, we show that the RhoGEF Trio mediates Rac1 activation in netrin-1 signaling. We found that Trio interacts with the netrin-1 receptor DCC in mouse embryonic brains and that netrin-1-induced Rac1 activation in brain is impaired in the absence of Trio. Trio(-/-) cortical neurons fail to extend neurites in response to netrin-1, while they are able to respond to glutamate. Accordingly, netrin-1-induced commissural axon outgrowth is reduced in Trio(-/-) spinal cord explants, and the guidance of commissural axons toward the floor plate is affected by the absence of Trio. The anterior commissure is absent in Trio-null embryos, and netrin-1/DCC-dependent axonal projections that form the internal capsule and the corpus callosum are defective in the mutants. Taken together, these findings establish Trio as a GEF that mediates netrin-1 signaling in axon outgrowth and guidance through its ability to activate Rac1.
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Sarkisian MR, Bartley CM, Rakic P. Trouble making the first move: interpreting arrested neuronal migration in the cerebral cortex. Trends Neurosci 2008; 31:54-61. [PMID: 18201775 DOI: 10.1016/j.tins.2007.11.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2007] [Revised: 11/30/2007] [Accepted: 11/30/2007] [Indexed: 12/29/2022]
Abstract
Postmitotic cortical neurons that fail to initiate migration can remain near their site of origin and form persistent periventricular nodular heterotopia (PH). In human telencephalon, this malformation is most commonly associated with Filamin-A (FLNa) mutations. The lack of genetic animal models that reliably produce PH has delayed our understanding of the underlying molecular mechanisms. This review examines PH pathogenesis using a new mouse model. Although PH have not been observed in Flna-deficient mice generated thus far, the loss of MEKK4, a regulator of Flna, produces striking PH in mice and offers insight into the mechanisms involved in neuronal migration initiation. Elucidating the basic functions of FLNa and associated molecules is crucial for understanding the causes of PH and for developing prevention for at-risk patients.
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Affiliation(s)
- Matthew R Sarkisian
- Department of Neurobiology and Kavli Institute of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
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Lutz S, Shankaranarayanan A, Coco C, Ridilla M, Nance MR, Vettel C, Baltus D, Evelyn CR, Neubig RR, Wieland T, Tesmer JJG. Structure of Galphaq-p63RhoGEF-RhoA complex reveals a pathway for the activation of RhoA by GPCRs. Science 2008; 318:1923-7. [PMID: 18096806 DOI: 10.1126/science.1147554] [Citation(s) in RCA: 169] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The guanine nucleotide exchange factor p63RhoGEF is an effector of the heterotrimeric guanine nucleotide-binding protein (G protein) Galphaq and thereby links Galphaq-coupled receptors (GPCRs) to the activation of the small-molecular-weight G protein RhoA. We determined the crystal structure of the Galphaq-p63RhoGEF-RhoA complex, detailing the interactions of Galphaq with the Dbl and pleckstrin homology (DH and PH) domains of p63RhoGEF. These interactions involve the effector-binding site and the C-terminal region of Galphaq and appear to relieve autoinhibition of the catalytic DH domain by the PH domain. Trio, Duet, and p63RhoGEF are shown to constitute a family of Galphaq effectors that appear to activate RhoA both in vitro and in intact cells. We propose that this structure represents the crux of an ancient signal transduction pathway that is expected to be important in an array of physiological processes.
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Affiliation(s)
- Susanne Lutz
- Institute of Experimental and Clinical Pharmacology and Toxicology, Medical Faculty Mannheim, University of Heidelberg, Maybachstrasse 14, D-68169 Mannheim, Germany
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Williams SL, Lutz S, Charlie NK, Vettel C, Ailion M, Coco C, Tesmer JJG, Jorgensen EM, Wieland T, Miller KG. Trio's Rho-specific GEF domain is the missing Galpha q effector in C. elegans. Genes Dev 2007; 21:2731-46. [PMID: 17942708 DOI: 10.1101/gad.1592007] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The Galpha(q) pathway is essential for animal life and is a central pathway for driving locomotion, egg laying, and growth in Caenorhabditis elegans, where it exerts its effects through EGL-8 (phospholipase Cbeta [PLCbeta]) and at least one other effector. To find the missing effector, we performed forward genetic screens to suppress the slow growth and hyperactive behaviors of mutants with an overactive Galpha(q) pathway. Four suppressor mutations disrupted the Rho-specific guanine-nucleotide exchange factor (GEF) domain of UNC-73 (Trio). The mutations produce defects in neuronal function, but not neuronal development, that cause sluggish locomotion similar to animals lacking EGL-8 (PLCbeta). Strains containing null mutations in both EGL-8 (PLCbeta) and UNC-73 (Trio RhoGEF) have strong synthetic phenotypes that phenocopy the arrested growth and near-complete paralysis of Galpha(q)-null mutants. Using cell-based and biochemical assays, we show that activated C. elegans Galpha(q) synergizes with Trio RhoGEF to activate RhoA. Activated Galpha(q) and Trio RhoGEF appear to be part of a signaling complex, because they coimmunoprecipitate when expressed together in cells. Our results show that Trio's Rho-specific GEF domain is a major Galpha(q) effector that, together with PLCbeta, mediates the Galpha(q) signaling that drives the locomotion, egg laying, and growth of the animal.
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Affiliation(s)
- Stacey L Williams
- Program in Molecular, Cell, and Developmental Biology, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma 73104, USA
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Charrasse S, Comunale F, Fortier M, Portales-Casamar E, Debant A, Gauthier-Rouvière C. M-cadherin activates Rac1 GTPase through the Rho-GEF trio during myoblast fusion. Mol Biol Cell 2007; 18:1734-43. [PMID: 17332503 PMCID: PMC1855016 DOI: 10.1091/mbc.e06-08-0766] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cadherins are transmembrane glycoproteins that mediate Ca(2+)-dependent homophilic cell-cell adhesion and play crucial role during skeletal myogenesis. M-cadherin is required for myoblast fusion into myotubes, but its mechanisms of action remain unknown. The goal of this study was to cast some light on the nature of the M-cadherin-mediated signals involved in myoblast fusion into myotubes. We found that the Rac1 GTPase activity is increased at the time of myoblast fusion and it is required for this process. Moreover, we showed that M-cadherin-dependent adhesion activates Rac1 and demonstrated the formation of a multiproteic complex containing M-cadherin, the Rho-GEF Trio, and Rac1 at the onset of myoblast fusion. Interestingly, Trio knockdown efficiently blocked both the increase in Rac1-GTP levels, observed after M-cadherin-dependent contact formation, and myoblast fusion. We conclude that M-cadherin-dependent adhesion can activate Rac1 via the Rho-GEF Trio at the time of myoblast fusion.
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Affiliation(s)
- Sophie Charrasse
- Centre de Recherches de Biochimie Macromoléculaire, Centre National de la Recherche Scientifique, IFR 122, 34293 Montpellier, France
| | - Franck Comunale
- Centre de Recherches de Biochimie Macromoléculaire, Centre National de la Recherche Scientifique, IFR 122, 34293 Montpellier, France
| | - Mathieu Fortier
- Centre de Recherches de Biochimie Macromoléculaire, Centre National de la Recherche Scientifique, IFR 122, 34293 Montpellier, France
| | - Elodie Portales-Casamar
- Centre de Recherches de Biochimie Macromoléculaire, Centre National de la Recherche Scientifique, IFR 122, 34293 Montpellier, France
| | - Anne Debant
- Centre de Recherches de Biochimie Macromoléculaire, Centre National de la Recherche Scientifique, IFR 122, 34293 Montpellier, France
| | - Cécile Gauthier-Rouvière
- Centre de Recherches de Biochimie Macromoléculaire, Centre National de la Recherche Scientifique, IFR 122, 34293 Montpellier, France
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Chhatriwala MK, Betts L, Worthylake DK, Sondek J. The DH and PH domains of Trio coordinately engage Rho GTPases for their efficient activation. J Mol Biol 2007; 368:1307-20. [PMID: 17391702 PMCID: PMC1890047 DOI: 10.1016/j.jmb.2007.02.060] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2006] [Revised: 02/13/2007] [Accepted: 02/16/2007] [Indexed: 12/20/2022]
Abstract
Rho-family GTPases are activated by the exchange of bound GDP for GTP, a process that is catalyzed by Dbl-family guanine nucleotide exchange factors (GEFs). The catalytic unit of Dbl-family GEFs consists of a Dbl homology (DH) domain followed almost invariantly by a pleckstrin-homology (PH) domain. The majority of the catalytic interface forms between the switch regions of the GTPase and the DH domain, but full catalytic activity often requires the associated PH domain. Although PH domains are usually characterized as lipid-binding regions, they also participate in protein-protein interactions. For example, the DH-associated PH domain of Dbs must contact its cognate GTPases for efficient exchange. Similarly, the N-terminal DH/PH fragment of Trio, which catalyzes exchange on both Rac1 and RhoG, is fourfold more active in vitro than the isolated DH domain. Given continued uncertainty regarding functional roles of DH-associated PH domains, we have undertaken structural and functional analyses of the N-terminal DH/PH cassette of Trio. The crystal structure of this fragment of Trio bound to nucleotide-depleted Rac1 highlights the engagement of the PH domain with Rac1 and substitution of residues involved in this interface substantially diminishes activation of Rac1 and RhoG. Also, these mutations significantly reduce the ability of full-length Trio to induce neurite outgrowth dependent on RhoG activation in PC-12 cells. Overall, these studies substantiate a general role for DH-associated PH domains in engaging Rho GTPases directly for efficient guanine nucleotide exchange and support a parsimonious explanation for the essentially invariant linkage between DH and PH domains.
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Affiliation(s)
- Mariya K Chhatriwala
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599-7295, USA
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Adamowicz M, Radlwimmer B, Rieker RJ, Mertens D, Schwarzbach M, Schraml P, Benner A, Lichter P, Mechtersheimer G, Joos S. Frequent amplifications and abundant expression of TRIO, NKD2, and IRX2 in soft tissue sarcomas. Genes Chromosomes Cancer 2006; 45:829-38. [PMID: 16752383 DOI: 10.1002/gcc.20343] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Copy number gains and high-level amplifications of the short arm of chromosome 5 are frequently observed in soft tissue sarcomas. To identify genes from this region possibly involved in tumor progression, we analyzed 34 soft tissue sarcomas (10 pleomorphic and 8 dedifferentiated liposarcomas, 6 malignant fibrous histiocytomas, and 10 malignant peripheral nerve sheath tumors (MPNST)) using a DNA microarray including 418 BAC clones representing 99% of chromosome arm 5p. In seven tumors, distinct high-level amplifications were identified affecting four different subregions. From these regions, genes TERT, TRIO, SKP2, FBXO32, NKD2, SLC6A3, IRX2, POLS, FYB, PTGER4, and FGF10 were selected for detailed quantitative expression analysis (RQ-PCR) based on their potential tumorigenic function. Of these, TRIO, coding for a guanidine nucleotide exchange factor, was consistently overexpressed in all cases, while IRX2 and NKD2, both involved in the regulation of developmental processes via the WNT pathway, showed a characteristic expression only in MPNSTs. Detailed nonparametric multidimensional scaling analysis further showed that the expression of TRIO, IRX2, and NKD2 strongly correlated with the gene copy number. In conclusion, we found TRIO, IRX2, and NKD2 frequently affected by high-level amplifications as well as up-regulated in a gene-dosage dependent manner. Thus, these genes represent candidate targets of 5p amplifications in soft tissue sarcomas and might play a crucial role during the progression of this disease.
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Affiliation(s)
- Martyna Adamowicz
- Division of Molecular Genetics (B060), German Cancer Research Center, Im Neuenheimer Feld 280, Heidelberg 69120, Germany
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