1
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Ginn L, Maltas J, Baker MJ, Chaturvedi A, Wilson L, Guilbert R, Amaral FMR, Priest L, Mole H, Blackhall F, Diamantopoulou Z, Somervaille TCP, Hurlstone A, Malliri A. A TIAM1-TRIM28 complex mediates epigenetic silencing of protocadherins to promote migration of lung cancer cells. Proc Natl Acad Sci U S A 2023; 120:e2300489120. [PMID: 37748077 PMCID: PMC10556593 DOI: 10.1073/pnas.2300489120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 08/03/2023] [Indexed: 09/27/2023] Open
Abstract
Lung cancer is the leading cause of cancer deaths. Its high mortality is associated with high metastatic potential. Here, we show that the RAC1-selective guanine nucleotide exchange factor T cell invasion and metastasis-inducing protein 1 (TIAM1) promotes cell migration and invasion in the most common subtype of lung cancer, non-small-cell lung cancer (NSCLC), through an unexpected nuclear function. We show that TIAM1 interacts with TRIM28, a master regulator of gene expression, in the nucleus of NSCLC cells. We reveal that a TIAM1-TRIM28 complex promotes epithelial-to-mesenchymal transition, a phenotypic switch implicated in cell migration and invasion. This occurs through H3K9me3-induced silencing of protocadherins and by decreasing E-cadherin expression, thereby antagonizing cell-cell adhesion. Consistently, TIAM1 or TRIM28 depletion suppresses the migration of NSCLC cells, while migration is restored by the simultaneous depletion of protocadherins. Importantly, high nuclear TIAM1 in clinical specimens is associated with advanced-stage lung adenocarcinoma, decreased patient survival, and inversely correlates with E-cadherin expression.
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Affiliation(s)
- Lucy Ginn
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, ManchesterM20 4BX, United Kingdom
| | - Joe Maltas
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, ManchesterM20 4BX, United Kingdom
| | - Martin J. Baker
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, ManchesterM20 4BX, United Kingdom
| | - Anshuman Chaturvedi
- The Christie National Health Service Foundation Trust, ManchesterM20 4BX, United Kingdom
| | - Leah Wilson
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, ManchesterM20 4BX, United Kingdom
| | - Ryan Guilbert
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, ManchesterM20 4BX, United Kingdom
| | - Fabio M. R. Amaral
- Leukaemia Biology Laboratory, Cancer Research UK Manchester Institute, The University of Manchester, ManchesterM20 4BX, United Kingdom
| | - Lynsey Priest
- The Christie National Health Service Foundation Trust, ManchesterM20 4BX, United Kingdom
| | - Holly Mole
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology Medicine and Health, The University of Manchester, ManchesterM13 9PT, United Kingdom
| | - Fiona Blackhall
- The Christie National Health Service Foundation Trust, ManchesterM20 4BX, United Kingdom
- Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology Medicine and Health, The University of Manchester, ManchesterM13 9PT, United Kingdom
| | - Zoi Diamantopoulou
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, ManchesterM20 4BX, United Kingdom
| | - Tim C. P. Somervaille
- Leukaemia Biology Laboratory, Cancer Research UK Manchester Institute, The University of Manchester, ManchesterM20 4BX, United Kingdom
| | - Adam Hurlstone
- Division of Immunology, Infection and Respiratory Medicine, School of Biological Sciences, Faculty of Biology Medicine and Health, The University of Manchester, ManchesterM13 9PT, United Kingdom
| | - Angeliki Malliri
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, ManchesterM20 4BX, United Kingdom
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2
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Quiroga X, Walani N, Disanza A, Chavero A, Mittens A, Tebar F, Trepat X, Parton RG, Geli MI, Scita G, Arroyo M, Le Roux AL, Roca-Cusachs P. A mechanosensing mechanism controls plasma membrane shape homeostasis at the nanoscale. eLife 2023; 12:e72316. [PMID: 37747150 PMCID: PMC10569792 DOI: 10.7554/elife.72316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 09/24/2023] [Indexed: 09/26/2023] Open
Abstract
As cells migrate and experience forces from their surroundings, they constantly undergo mechanical deformations which reshape their plasma membrane (PM). To maintain homeostasis, cells need to detect and restore such changes, not only in terms of overall PM area and tension as previously described, but also in terms of local, nanoscale topography. Here, we describe a novel phenomenon, by which cells sense and restore mechanically induced PM nanoscale deformations. We show that cell stretch and subsequent compression reshape the PM in a way that generates local membrane evaginations in the 100 nm scale. These evaginations are recognized by I-BAR proteins, which triggers a burst of actin polymerization mediated by Rac1 and Arp2/3. The actin polymerization burst subsequently re-flattens the evagination, completing the mechanochemical feedback loop. Our results demonstrate a new mechanosensing mechanism for PM shape homeostasis, with potential applicability in different physiological scenarios.
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Affiliation(s)
- Xarxa Quiroga
- Institute for Bioengineering of Catalonia, the Barcelona Institute of Technology (BIST)BarcelonaSpain
- Departament de Biomedicina, Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de BarcelonaBarcelonaSpain
| | - Nikhil Walani
- Department of Applied Mechanics, IIT DelhiNew DelhiIndia
| | - Andrea Disanza
- IFOM ETS - The AIRC Institute of Molecular OncologyMilanItaly
| | - Albert Chavero
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Facultat de Medicina i Ciències de la Salut, Centre de Recerca Biomèdica CELLEX, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de BarcelonaBarcelonaSpain
| | - Alexandra Mittens
- Institute for Bioengineering of Catalonia, the Barcelona Institute of Technology (BIST)BarcelonaSpain
| | - Francesc Tebar
- Departament de Biomedicina, Unitat de Biologia Cel·lular, Facultat de Medicina i Ciències de la Salut, Centre de Recerca Biomèdica CELLEX, Institut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Universitat de BarcelonaBarcelonaSpain
| | - Xavier Trepat
- Institute for Bioengineering of Catalonia, the Barcelona Institute of Technology (BIST)BarcelonaSpain
| | - Robert G Parton
- Institute for Molecular Bioscience and Centre for Microscopy and Microanalysis, University of QueenslandBrisbaneAustralia
| | | | - Giorgio Scita
- IFOM ETS - The AIRC Institute of Molecular OncologyMilanItaly
- Department of Oncology and Haemato-Oncology, University of MilanMilanItaly
| | - Marino Arroyo
- Institute for Bioengineering of Catalonia, the Barcelona Institute of Technology (BIST)BarcelonaSpain
- Universitat Politècnica de Catalunya (UPC), Campus Nord, Carrer de Jordi GironaBarcelonaSpain
- Centre Internacional de Mètodes Numèrics en Enginyeria (CIMNE)BarcelonaSpain
| | - Anabel-Lise Le Roux
- Institute for Bioengineering of Catalonia, the Barcelona Institute of Technology (BIST)BarcelonaSpain
| | - Pere Roca-Cusachs
- Institute for Bioengineering of Catalonia, the Barcelona Institute of Technology (BIST)BarcelonaSpain
- Departament de Biomedicina, Unitat de Biofísica i Bioenginyeria, Facultat de Medicina i Ciències de la Salut, Universitat de BarcelonaBarcelonaSpain
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3
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Hladyshau S, Stoop JP, Kamada K, Nie S, Tsygankov D. Spatiotemporal Coordination of Rac1 and Cdc42 at the Whole Cell Level during Cell Ruffling. Cells 2023; 12:1638. [PMID: 37371108 DOI: 10.3390/cells12121638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/06/2023] [Accepted: 06/09/2023] [Indexed: 06/29/2023] Open
Abstract
Rho-GTPases are central regulators within a complex signaling network that controls cytoskeletal organization and cell movement. The network includes multiple GTPases, such as the most studied Rac1, Cdc42, and RhoA, along with their numerous effectors that provide mutual regulation through feedback loops. Here we investigate the temporal and spatial relationship between Rac1 and Cdc42 during membrane ruffling, using a simulation model that couples GTPase signaling with cell morphodynamics and captures the GTPase behavior observed with FRET-based biosensors. We show that membrane velocity is regulated by the kinetic rate of GTPase activation rather than the concentration of active GTPase. Our model captures both uniform and polarized ruffling. We also show that cell-type specific time delays between Rac1 and Cdc42 activation can be reproduced with a single signaling motif, in which the delay is controlled by feedback from Cdc42 to Rac1. The resolution of our simulation output matches those of time-lapsed recordings of cell dynamics and GTPase activity. Our data-driven modeling approach allows us to validate simulation results with quantitative precision using the same pipeline for the analysis of simulated and experimental data.
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Affiliation(s)
- Siarhei Hladyshau
- School of Biology, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
| | - Jorik P Stoop
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
| | - Kosei Kamada
- Faculty of Medicine, The University of Tokyo, Tokyo 113-8654, Japan
| | - Shuyi Nie
- School of Biology, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Denis Tsygankov
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
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4
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Hladyshau S, Stoop JP, Kamada K, Nie S, Tsygankov DV. Spatiotemporal coordination of Rac1 and Cdc42 at the whole cell level during cell ruffling. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.31.535147. [PMID: 37034645 PMCID: PMC10081307 DOI: 10.1101/2023.03.31.535147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Rho-GTPases are central regulators within a complex signaling network that controls the cytoskeletal organization and cell movement. This network includes multiple GTPases, such as the most studied Rac1, Cdc42, and RhoA, and their numerous effectors that provide mutual regulation and feedback loops. Here we investigate the temporal and spatial relationship between Rac1 and Cdc42 during membrane ruffling using a simulation model which couples GTPase signaling with cell morphodynamics to capture the GTPase behavior observed with FRET-based biosensors. We show that membrane velocity is regulated by the kinetic rate of GTPase activation rather than the concentration of active GTPase. Our model captures both uniform and polarized ruffling. We also show that cell-type specific time delays between Rac1 and Cdc42 activation can be reproduced with a single signaling motif, in which the delay is controlled by feedback from Cdc42 to Rac1. The resolution of our simulation output matches those of the time-lapsed recordings of cell dynamics and GTPase activity. This approach allows us to validate simulation results with quantitative precision using the same pipeline for the analysis of simulated and experimental data.
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5
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Grubisha MJ, DeGiosio RA, Wills ZP, Sweet RA. Trio and Kalirin as unique enactors of Rho/Rac spatiotemporal precision. Cell Signal 2022; 98:110416. [PMID: 35872089 DOI: 10.1016/j.cellsig.2022.110416] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/18/2022] [Accepted: 07/19/2022] [Indexed: 12/18/2022]
Abstract
Rac1 and RhoA are among the most widely studied small GTPases. The classic dogma surrounding their biology has largely focused on their activity as an "on/off switch" of sorts. However, the advent of more sophisticated techniques, such as genetically-encoded FRET-based sensors, has afforded the ability to delineate the spatiotemporal regulation of Rac1 and RhoA. As a result, there has been a shift from this simplistic global view to one incorporating the precision of spatiotemporal modularity. This review summarizes emerging data surrounding the roles of Rac1 and RhoA as cytoskeletal regulators and examines how these new data have led to a revision of the traditional dogma which placed Rac1 and RhoA in antagonistic pathways. This more recent evidence suggests that rather than absolute activity levels, it is the tight spatiotemporal regulation of Rac1 and RhoA across multiple roles, from oppositional to complementary, that is necessary to execute coordinated cytoskeletal processes affecting cell structure, function, and migration. We focus on how Kalirin and Trio, as dual GEFs that target Rac1 and RhoA, are uniquely designed to provide the spatiotemporally-precise shifts in Rac/Rho balance which mediate changes in neuronal structure and function, particularly by way of cytoskeletal rearrangements. Finally, we review how alterations in Trio and/or Kalirin function are associated with cellular abnormalities and neuropsychiatric disease.
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Affiliation(s)
- M J Grubisha
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - R A DeGiosio
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Z P Wills
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - R A Sweet
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA; Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA.
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6
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Kim HS, Suh JS, Jang YK, Ahn SH, Choi GH, Yang JY, Lim GH, Jung Y, Jiang J, Sun J, Suk M, Wang Y, Kim TJ. Förster Resonance Energy Transfer-Based Single-Cell Imaging Reveals Piezo1-Induced Ca 2+ Flux Mediates Membrane Ruffling and Cell Survival. Front Cell Dev Biol 2022; 10:865056. [PMID: 35646889 PMCID: PMC9136143 DOI: 10.3389/fcell.2022.865056] [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: 01/29/2022] [Accepted: 04/25/2022] [Indexed: 01/18/2023] Open
Abstract
A mechanosensitive ion channel, Piezo1 induces non-selective cation flux in response to various mechanical stresses. However, the biological interpretation and underlying mechanisms of cells resulting from Piezo1 activation remain elusive. This study elucidates Piezo1-mediated Ca2+ influx driven by channel activation and cellular behavior using novel Förster Resonance Energy Transfer (FRET)-based biosensors and single-cell imaging analysis. Results reveal that extracellular Ca2+ influx via Piezo1 requires intact caveolin, cholesterol, and cytoskeletal support. Increased cytoplasmic Ca2+ levels enhance PKA, ERK, Rac1, and ROCK activity, which have the potential to promote cancer cell survival and migration. Furthermore, we demonstrate that Piezo1-mediated Ca2+ influx upregulates membrane ruffling, a characteristic feature of cancer cell metastasis, using spatiotemporal image correlation spectroscopy. Thus, our findings provide new insights into the function of Piezo1, suggesting that Piezo1 plays a significant role in the behavior of cancer cells.
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Affiliation(s)
- Heon-Su Kim
- Department of Integrated Biological Science, Pusan National University, Pusan, South Korea,Institute of Systems Biology, Pusan National University, Pusan, South Korea
| | - Jung-Soo Suh
- Department of Integrated Biological Science, Pusan National University, Pusan, South Korea
| | - Yoon-Kwan Jang
- Department of Integrated Biological Science, Pusan National University, Pusan, South Korea
| | - Sang-Hyun Ahn
- Department of Integrated Biological Science, Pusan National University, Pusan, South Korea
| | - Gyu-Ho Choi
- Department of Integrated Biological Science, Pusan National University, Pusan, South Korea
| | - Jin-Young Yang
- Department of Integrated Biological Science, Pusan National University, Pusan, South Korea
| | - Gah-Hyun Lim
- Department of Integrated Biological Science, Pusan National University, Pusan, South Korea
| | - Youngmi Jung
- Department of Integrated Biological Science, Pusan National University, Pusan, South Korea
| | - Jie Jiang
- Department of Cell Biology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Jie Sun
- Department of Cell Biology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Myungeun Suk
- Department of Mechanical Engineering, Dong-Eui University, Pusan, South Korea
| | - Yingxiao Wang
- Department of Bioengineering, Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Tae-Jin Kim
- Department of Integrated Biological Science, Pusan National University, Pusan, South Korea,Institute of Systems Biology, Pusan National University, Pusan, South Korea,Department of Biological Sciences, Pusan National University, Pusan, South Korea,*Correspondence: Tae-Jin Kim,
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7
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Duman JG, Blanco FA, Cronkite CA, Ru Q, Erikson KC, Mulherkar S, Saifullah AB, Firozi K, Tolias KF. Rac-maninoff and Rho-vel: The symphony of Rho-GTPase signaling at excitatory synapses. Small GTPases 2022; 13:14-47. [PMID: 33955328 PMCID: PMC9707551 DOI: 10.1080/21541248.2021.1885264] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 01/22/2021] [Accepted: 01/28/2021] [Indexed: 01/15/2023] Open
Abstract
Synaptic connections between neurons are essential for every facet of human cognition and are thus regulated with extreme precision. Rho-family GTPases, molecular switches that cycle between an active GTP-bound state and an inactive GDP-bound state, comprise a critical feature of synaptic regulation. Rho-GTPases are exquisitely controlled by an extensive suite of activators (GEFs) and inhibitors (GAPs and GDIs) and interact with many different signalling pathways to fulfill their roles in orchestrating the development, maintenance, and plasticity of excitatory synapses of the central nervous system. Among the mechanisms that control Rho-GTPase activity and signalling are cell surface receptors, GEF/GAP complexes that tightly regulate single Rho-GTPase dynamics, GEF/GAP and GEF/GEF functional complexes that coordinate multiple Rho-family GTPase activities, effector positive feedback loops, and mutual antagonism of opposing Rho-GTPase pathways. These complex regulatory mechanisms are employed by the cells of the nervous system in almost every step of development, and prominently figure into the processes of synaptic plasticity that underlie learning and memory. Finally, misregulation of Rho-GTPases plays critical roles in responses to neuronal injury, such as traumatic brain injury and neuropathic pain, and in neurodevelopmental and neurodegenerative disorders, including intellectual disability, autism spectrum disorder, schizophrenia, and Alzheimer's Disease. Thus, decoding the mechanisms of Rho-GTPase regulation and function at excitatory synapses has great potential for combatting many of the biggest current challenges in mental health.
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Affiliation(s)
- Joseph G. Duman
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Francisco A. Blanco
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Integrative Molecular and Biomedical Science Graduate Program, Baylor College of Medicine, Houston, TX, USA
| | - Christopher A. Cronkite
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
- Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, USA
| | - Qin Ru
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Kelly C. Erikson
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Shalaka Mulherkar
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Ali Bin Saifullah
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Karen Firozi
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Kimberley F. Tolias
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
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8
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Maltas J, Reed H, Porter A, Malliri A. Mechanisms and consequences of dysregulation of the Tiam family of Rac activators in disease. Biochem Soc Trans 2020; 48:2703-2719. [PMID: 33200195 DOI: 10.1042/bst20200481] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/16/2020] [Accepted: 10/16/2020] [Indexed: 12/14/2022]
Abstract
The Tiam family proteins - Tiam1 and Tiam2/STEF - are Rac1-specific Guanine Nucleotide Exchange Factors (GEFs) with important functions in epithelial, neuronal, immune and other cell types. Tiam GEFs regulate cellular migration, proliferation and survival, mainly through activating and directing Rac1 signalling. Dysregulation of the Tiam GEFs is significantly associated with human diseases including cancer, immunological and neurological disorders. Uncovering the mechanisms and consequences of dysregulation is therefore imperative to improving the diagnosis and treatment of diseases. Here we compare and contrast the subcellular localisation and function of Tiam1 and Tiam2/STEF, and review the evidence for their dysregulation in disease.
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Affiliation(s)
- Joe Maltas
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Alderley Park SK10 4TG, U.K
| | - Hannah Reed
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Alderley Park SK10 4TG, U.K
| | - Andrew Porter
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Alderley Park SK10 4TG, U.K
| | - Angeliki Malliri
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Alderley Park SK10 4TG, U.K
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9
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Arp2/3-Branched Actin Maintains an Active Pool of GTP-RhoA and Controls RhoA Abundance. Cells 2019; 8:cells8101264. [PMID: 31623230 PMCID: PMC6830327 DOI: 10.3390/cells8101264] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 10/03/2019] [Accepted: 10/15/2019] [Indexed: 01/23/2023] Open
Abstract
Small GTPases regulate cytoskeletal dynamics, cell motility, and division under precise spatiotemporal control. Different small GTPases exhibit cross talks to exert feedback response or to act in concert during signal transduction. However, whether and how specific cytoskeletal components' feedback to upstream signaling factors remains largely elusive. Here, we report an intriguing finding that disruption of the Arp2/3-branched actin specifically reduces RhoA activity but upregulates its total protein abundance. We further dissect the mechanisms underlying these circumstances and identify the altered cortactin/p190RhoGAP interaction and weakened CCM2/Smurf1 binding to be involved in GTP-RhoA reduction and total RhoA increase, respectively. Moreover, we find that cytokinesis defects induced by Arp2/3 inhibition can be rescued by activating RhoA. Our study reveals an intricate feedback from the actin cytoskeleton to the small GTPase. Our work highlights the role of Arp2/3-branched actin in signal transduction aside from its function in serving as critical cytoskeletal components to maintain cell morphology and motility.
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10
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Mehidi A, Rossier O, Schaks M, Chazeau A, Binamé F, Remorino A, Coppey M, Karatas Z, Sibarita JB, Rottner K, Moreau V, Giannone G. Transient Activations of Rac1 at the Lamellipodium Tip Trigger Membrane Protrusion. Curr Biol 2019; 29:2852-2866.e5. [DOI: 10.1016/j.cub.2019.07.035] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 04/25/2019] [Accepted: 07/11/2019] [Indexed: 01/22/2023]
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11
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Ramadass M, Johnson JL, Marki A, Zhang J, Wolf D, Kiosses WB, Pestonjamasp K, Ley K, Catz SD. The trafficking protein JFC1 regulates Rac1-GTP localization at the uropod controlling neutrophil chemotaxis and in vivo migration. J Leukoc Biol 2019; 105:1209-1224. [PMID: 30748033 DOI: 10.1002/jlb.1vma0818-320r] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 01/09/2019] [Accepted: 01/22/2019] [Indexed: 01/01/2023] Open
Abstract
Neutrophil chemotaxis is essential in responses to infection and underlies inflammation. In neutrophils, the small GTPase Rac1 has discrete functions at both the leading edge and in the retraction of the trailing structure at the cell's rear (uropod), but how Rac1 is regulated at the uropod is unknown. Here, we identified a mechanism mediated by the trafficking protein synaptotagmin-like 1 (SYTL1 or JFC1) that controls Rac1-GTP recycling from the uropod and promotes directional migration of neutrophils. JFC1-null neutrophils displayed defective polarization and impaired directional migration to N-formyl-methionine-leucyl-phenylalanine in vitro, but chemoattractant-induced actin remodeling, calcium signaling and Erk activation were normal in these cells. Defective chemotaxis was not explained by impaired azurophilic granule exocytosis associated with JFC1 deficiency. Mechanistically, we show that active Rac1 localizes at dynamic vesicles where endogenous JFC1 colocalizes with Rac1-GTP. Super-resolution microscopy (STORM) analysis shows adjacent distribution of JFC1 and Rac1-GTP, which increases upon activation. JFC1 interacts with Rac1-GTP in a Rab27a-independent manner to regulate Rac1-GTP trafficking. JFC1-null cells exhibited Rac1-GTP accumulation at the uropod and increased tail length, and Rac1-GTP uropod accumulation was recapitulated by inhibition of ROCK or by interference with microtubule remodeling. In vivo, neutrophil dynamic studies in mixed bone marrow chimeric mice show that JFC1-/- neutrophils are unable to move directionally toward the source of the chemoattractant, supporting the notion that JFC1 deficiency results in defective neutrophil migration. Our results suggest that defective Rac1-GTP recycling from the uropod affects directionality and highlight JFC1-mediated Rac1 trafficking as a potential target to regulate chemotaxis in inflammation and immunity.
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Affiliation(s)
- Mahalakshmi Ramadass
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, USA
| | - Jennifer L Johnson
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, USA
| | - Alex Marki
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA
| | - Jinzhong Zhang
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, USA
| | - Dennis Wolf
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA
| | - William B Kiosses
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, USA
| | - Kersi Pestonjamasp
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, USA
| | - Klaus Ley
- Division of Inflammation Biology, La Jolla Institute for Allergy and Immunology, La Jolla, California, USA
| | - Sergio D Catz
- Department of Molecular Medicine, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, USA
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12
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de Beco S, Vaidžiulytė K, Manzi J, Dalier F, di Federico F, Cornilleau G, Dahan M, Coppey M. Optogenetic dissection of Rac1 and Cdc42 gradient shaping. Nat Commun 2018; 9:4816. [PMID: 30446664 PMCID: PMC6240110 DOI: 10.1038/s41467-018-07286-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 10/19/2018] [Indexed: 12/22/2022] Open
Abstract
During cell migration, Rho GTPases spontaneously form spatial gradients that define the front and back of cells. At the front, active Cdc42 forms a steep gradient whereas active Rac1 forms a more extended pattern peaking a few microns away. What are the mechanisms shaping these gradients, and what is the functional role of the shape of these gradients? Here we report, using a combination of optogenetics and micropatterning, that Cdc42 and Rac1 gradients are set by spatial patterns of activators and deactivators and not directly by transport mechanisms. Cdc42 simply follows the distribution of Guanine nucleotide Exchange Factors, whereas Rac1 shaping requires the activity of a GTPase-Activating Protein, β2-chimaerin, which is sharply localized at the tip of the cell through feedbacks from Cdc42 and Rac1. Functionally, the spatial extent of Rho GTPases gradients governs cell migration, a sharp Cdc42 gradient maximizes directionality while an extended Rac1 gradient controls the speed. A steep gradient of Cdc42 is at the front of migrating cells, whereas the active Rac1 gradient is graded. Here the authors show that Cdc42 gradients follow the distribution of GEFs and govern direction of migration, while Rac1 gradients require the activity of the GAP β2-chimaerin and control cell speed.
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Affiliation(s)
- S de Beco
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, Sorbonne Université, CNRS, 75005, Paris, France
| | - K Vaidžiulytė
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, Sorbonne Université, CNRS, 75005, Paris, France
| | - J Manzi
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, Sorbonne Université, CNRS, 75005, Paris, France
| | - F Dalier
- PASTEUR, Département de chimie, École normale supérieure, CNRS UMR 8640, PSL Research University, Sorbonne Université, 75005, Paris, France
| | - F di Federico
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, Sorbonne Université, CNRS, 75005, Paris, France
| | - G Cornilleau
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, Sorbonne Université, CNRS, 75005, Paris, France
| | - M Dahan
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, Sorbonne Université, CNRS, 75005, Paris, France
| | - M Coppey
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, Sorbonne Université, CNRS, 75005, Paris, France.
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13
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Csépányi-Kömi R, Pásztor M, Bartos B, Ligeti E. The neglected terminators: Rho family GAPs in neutrophils. Eur J Clin Invest 2018; 48 Suppl 2:e12993. [PMID: 29972685 DOI: 10.1111/eci.12993] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 07/02/2018] [Indexed: 12/13/2022]
Abstract
BACKGROUND GTPase-activating proteins (GAPs) accelerate the rate of hydrolysis of GTP bound to small GTPases, thereby limiting the prevalence and concentration of the active, GTP-bound form of these proteins. The large number of potential GAPs acting on members of the Rho family of small GTPases raises the question of specificity or redundancy. RESULTS In this review, we summarize experimental data obtained on the role of Rho family GAPs in neutrophils, highlight cases where more than one GAP is involved in a physiological function and show examples that GAPs can be involved not only in termination but also in initiation of cellular processes. We demonstrate that the expression-level regulation of GAPs may also occur in short-living cells such as neutrophils. Finally, we provide insight into the existence and structure of molecular complexes in which Rho family GAPs are involved. CONCLUSION GAPs play more complex and varied roles than being simple terminators of cellular processes.
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Affiliation(s)
| | - Máté Pásztor
- Department of Physiology, Semmelweis University, Budapest, Hungary
| | - Balázs Bartos
- Department of Physiology, Semmelweis University, Budapest, Hungary
| | - Erzsébet Ligeti
- Department of Physiology, Semmelweis University, Budapest, Hungary
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14
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Van Geel O, Hartsuiker R, Gadella TWJ. Increasing spatial resolution of photoregulated GTPases through immobilized peripheral membrane proteins. Small GTPases 2018; 11:441-450. [PMID: 30182785 PMCID: PMC7549704 DOI: 10.1080/21541248.2018.1507411] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Light-induced dimerizing systems, e.g. iLID, are an increasingly utilized optogenetics tool to perturb cellular signaling. The major benefit of this technique is that it allows external spatiotemporal control over protein localization with sub-cellular specificity. However, when it comes to local recruitment of signaling components to the plasmamembrane, this precision in localization is easily lost due to rapid diffusion of the membrane anchor. In this study, we explore different approaches of countering the diffusion of peripheral membrane anchors, to the point where we detect immobilized fractions with iFRAP on a timescale of several minutes. One method involves simultaneous binding of the membrane anchor to a secondary structure, the microtubules. The other strategy utilizes clustering of the anchor into large immobile structures, which can also be interlinked by employing tandem recruitable domains. For both approaches, the anchors are peripheral membrane constructs, which also makes them suitable for in vitro use. Upon combining these slower diffusing anchors with recruitable guanine exchange factors (GEFs), we show that we can elicit much more localized morphological responses from Rac1 and Cdc42 as compared to a regular CAAX-box based membrane anchor in living cells. Thanks to these new slow diffusing anchors, more precisely defined membrane recruitment experiments are now possible.
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Affiliation(s)
- Orry Van Geel
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam , Amsterdam, The Netherlands
| | - Roland Hartsuiker
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, van Leeuwenhoek Centre for Advanced Microscopy, University of Amsterdam , Amsterdam, The Netherlands
| | - Theodorus W J Gadella
- 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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15
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Filić V, Marinović M, Šoštar M, Weber I. Modulation of small GTPase activity by NME proteins. J Transl Med 2018; 98:589-601. [PMID: 29434248 DOI: 10.1038/s41374-018-0023-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 12/06/2017] [Accepted: 12/29/2017] [Indexed: 12/26/2022] Open
Abstract
NME proteins are reported to influence signal transduction activity of small GTPases from the Ras superfamily by diverse mechanisms in addition to their generic NDP kinase activity, which replenishes the cytoplasmic pool of GTP. Comprehensive evidence shows that NME proteins modulate the activity of Ras GTPases, in particular members of the Rho family, via binding to their major activators GEFs. Direct interaction between several NMEs and Ras GTPases were also indicated in vitro and in vivo. These modes of regulation are mainly independent of the NME's kinase activity. NMEs also modulate the Ras-mediated signal transduction by interfering with the formation of a Ras signaling complex at the plasma membrane. In several examples, NMEs were proposed to perform the role of GAP proteins by promoting hydrolysis of the bound GTP, but this activity still requires additional verification. Early suggestions that NMEs can activate small GTPases by direct phosphorylation of the bound GDP, or by high-rate loading of GTP onto a closely apposed GTPase, were largely dismissed. In this review article, we survey and put into perspective published examples of identified and hypothetical mechanisms of Ras signaling modulation by NME proteins. We also point out involvement of NMEs in the transcriptional regulation of components of Ras GTPases-mediated signal transduction pathways, and reciprocal regulation of NME function by small GTPases, particularly related to NME's binding to membranes.
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Affiliation(s)
- Vedrana Filić
- Ruđer Bošković Institute, Division of Molecular Biology, Bijenička 54, HR-10000, Zagreb, Croatia
| | - Maja Marinović
- Ruđer Bošković Institute, Division of Molecular Biology, Bijenička 54, HR-10000, Zagreb, Croatia
| | - Marko Šoštar
- Ruđer Bošković Institute, Division of Molecular Biology, Bijenička 54, HR-10000, Zagreb, Croatia
| | - Igor Weber
- Ruđer Bošković Institute, Division of Molecular Biology, Bijenička 54, HR-10000, Zagreb, Croatia.
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16
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Lawson CD, Ridley AJ. Rho GTPase signaling complexes in cell migration and invasion. J Cell Biol 2018; 217:447-457. [PMID: 29233866 PMCID: PMC5800797 DOI: 10.1083/jcb.201612069] [Citation(s) in RCA: 304] [Impact Index Per Article: 50.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 10/23/2017] [Accepted: 11/17/2017] [Indexed: 12/02/2022] Open
Abstract
Cell migration is dependent on the dynamic formation and disassembly of actin filament-based structures, including lamellipodia, filopodia, invadopodia, and membrane blebs, as well as on cell-cell and cell-extracellular matrix adhesions. These processes all involve Rho family small guanosine triphosphatases (GTPases), which are regulated by the opposing actions of guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Rho GTPase activity needs to be precisely tuned at distinct cellular locations to enable cells to move in response to different environments and stimuli. In this review, we focus on the ability of RhoGEFs and RhoGAPs to form complexes with diverse binding partners, and describe how this influences their ability to control localized GTPase activity in the context of migration and invasion.
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Affiliation(s)
- Campbell D Lawson
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, England, UK
| | - Anne J Ridley
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, England, UK
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17
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Aspenström P. BAR Domain Proteins Regulate Rho GTPase Signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1111:33-53. [PMID: 30151649 DOI: 10.1007/5584_2018_259] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The Bin-Amphiphysin-Rvs (BAR) domain is a membrane lipid binding domain present in a wide variety of proteins, often proteins with a role in Rho-regulated signaling pathways. BAR domains do not only confer binding to lipid bilayers, they also possess a membrane sculpturing ability and thereby directly control the topology of biomembranes. BAR domain-containing proteins participate in a plethora of physiological processes but the common denominator is their capacity to link membrane dynamics to actin dynamics and thereby integrate processes such as endocytosis, exocytosis, vesicle trafficking, cell morphogenesis and cell migration. The Rho family of small GTPases constitutes an important bridging theme for many BAR domain-containing proteins. This review article will focus predominantly on the role of BAR proteins as regulators or effectors of Rho GTPases and it will only briefly discuss the structural and biophysical function of the BAR domains.
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Affiliation(s)
- Pontus Aspenström
- Department of Microbiology, and Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden.
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18
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Marei H, Malliri A. Rac1 in human diseases: The therapeutic potential of targeting Rac1 signaling regulatory mechanisms. Small GTPases 2017; 8:139-163. [PMID: 27442895 PMCID: PMC5584733 DOI: 10.1080/21541248.2016.1211398] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 07/05/2016] [Accepted: 07/05/2016] [Indexed: 12/11/2022] Open
Abstract
Abnormal Rac1 signaling is linked to a number of debilitating human diseases, including cancer, cardiovascular diseases and neurodegenerative disorders. As such, Rac1 represents an attractive therapeutic target, yet the search for effective Rac1 inhibitors is still underway. Given the adverse effects associated with Rac1 signaling perturbation, cells have evolved several mechanisms to ensure the tight regulation of Rac1 signaling. Thus, characterizing these mechanisms can provide invaluable information regarding major cellular events that lead to aberrant Rac1 signaling. Importantly, this information can be utilized to further facilitate the development of effective pharmacological modulators that can restore normal Rac1 signaling. In this review, we focus on the pathological role of Rac1 signaling, highlighting the benefits and potential drawbacks of targeting Rac1 in a clinical setting. Additionally, we provide an overview of available compounds that target key Rac1 regulatory mechanisms and discuss future therapeutic avenues arising from our understanding of these mechanisms.
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Affiliation(s)
- Hadir Marei
- Cell Signaling Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK
| | - Angeliki Malliri
- Cell Signaling Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK
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Marei H, Malliri A. GEFs: Dual regulation of Rac1 signaling. Small GTPases 2017; 8:90-99. [PMID: 27314616 PMCID: PMC5464116 DOI: 10.1080/21541248.2016.1202635] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 06/10/2016] [Accepted: 06/10/2016] [Indexed: 12/15/2022] Open
Abstract
GEFs play a critical role in regulating Rac1 signaling. They serve as signaling nodes converting upstream signals into downstream Rac1-driven cellular responses. Through associating with membrane-bound Rac1, GEFs facilitate the exchange of GDP for GTP, thereby activating Rac1. As a result, Rac1 undergoes conformational changes that mediate its interaction with downstream effectors, linking Rac1 to a multitude of physiological and pathological processes. Interestingly, there are at least 20 GEFs involved in Rac1 activation, suggesting a more complex role of GEFs in regulating Rac1 signaling apart from promoting the exchange of GDP for GTP. Indeed, accumulating evidence implicates GEFs in directing the specificity of Rac1-driven signaling cascades, although the underlying mechanisms were poorly defined. Recently, through conducting a comparative study, we highlighted the role of 2 Rac-specific GEFs, Tiam1 and P-Rex1, in dictating the biological outcome downstream of Rac1. Importantly, further proteomic analysis uncovered a GEF activity-independent function for both GEFs in modulating the Rac1 interactome, which results in the stimulation of GEF-specific signaling cascades. Here, we provide an overview of our recent findings and discuss the role of GEFs as master regulators of Rac1 signaling with a particular focus on GEF-mediated modulation of cell migration following Rac1 activation.
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Affiliation(s)
- Hadir Marei
- Cell Signaling Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK
| | - Angeliki Malliri
- Cell Signaling Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK
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20
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Marei H, Carpy A, Macek B, Malliri A. Proteomic analysis of Rac1 signaling regulation by guanine nucleotide exchange factors. Cell Cycle 2016; 15:1961-74. [PMID: 27152953 PMCID: PMC4968972 DOI: 10.1080/15384101.2016.1183852] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 04/13/2016] [Accepted: 04/22/2016] [Indexed: 10/30/2022] Open
Abstract
The small GTPase Rac1 is implicated in various cellular processes that are essential for normal cell function. Deregulation of Rac1 signaling has also been linked to a number of diseases, including cancer. The diversity of Rac1 functioning in cells is mainly attributed to its ability to bind to a multitude of downstream effectors following activation by Guanine nucleotide Exchange Factors (GEFs). Despite the identification of a large number of Rac1 binding partners, factors influencing downstream specificity are poorly defined, thus hindering the detailed understanding of both Rac1's normal and pathological functions. In a recent study, we demonstrated a role for 2 Rac-specific GEFs, Tiam1 and P-Rex1, in mediating Rac1 anti- versus pro-migratory effects, respectively. Importantly, via conducting a quantitative proteomic screen, we identified distinct changes in the Rac1 interactome following activation by either GEF, indicating that these opposing effects are mediated through GEF modulation of the Rac1 interactome. Here, we present the full list of identified Rac1 interactors together with functional annotation of the differentially regulated Rac1 binding partners. In light of this data, we also provide additional insights into known and novel signaling cascades that might account for the GEF-mediated Rac1-driven cellular effects.
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Affiliation(s)
- Hadir Marei
- Cell Signaling Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK
| | - Alejandro Carpy
- Proteome Center Tuebingen, Interfaculty Institute for Cell Biology, University of Tuebingen, Tuebingen, Germany
| | - Boris Macek
- Proteome Center Tuebingen, Interfaculty Institute for Cell Biology, University of Tuebingen, Tuebingen, Germany
| | - Angeliki Malliri
- Cell Signaling Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester, UK
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21
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Marei H, Carpy A, Woroniuk A, Vennin C, White G, Timpson P, Macek B, Malliri A. Differential Rac1 signalling by guanine nucleotide exchange factors implicates FLII in regulating Rac1-driven cell migration. Nat Commun 2016; 7:10664. [PMID: 26887924 PMCID: PMC4759627 DOI: 10.1038/ncomms10664] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 01/08/2016] [Indexed: 01/22/2023] Open
Abstract
The small GTPase Rac1 has been implicated in the formation and dissemination of tumours. Upon activation by guanine nucleotide exchange factors (GEFs), Rac1 associates with a variety of proteins in the cell thereby regulating various functions, including cell migration. However, activation of Rac1 can lead to opposing migratory phenotypes raising the possibility of exacerbating tumour progression when targeting Rac1 in a clinical setting. This calls for the identification of factors that influence Rac1-driven cell motility. Here we show that Tiam1 and P-Rex1, two Rac GEFs, promote Rac1 anti- and pro-migratory signalling cascades, respectively, through regulating the Rac1 interactome. In particular, we demonstrate that P-Rex1 stimulates migration through enhancing the interaction between Rac1 and the actin-remodelling protein flightless-1 homologue, to modulate cell contraction in a RhoA-ROCK-independent manner.
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Affiliation(s)
- Hadir Marei
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester M204BX, UK
| | - Alejandro Carpy
- Proteome Center Tuebingen, Interfaculty Institute for Cell Biology, University of Tuebingen, Tuebingen 72026, Germany
| | - Anna Woroniuk
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester M204BX, UK
| | - Claire Vennin
- Invasion and Metastasis Group, Garvan Institute of Medical Research, The Kinghorn Cancer Centre, Faculty of Medicine, St Vincent's Clinical School, University of New South Wales, Darlinghurst, New South Wales 2010, Australia
| | - Gavin White
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester M204BX, UK
| | - Paul Timpson
- Invasion and Metastasis Group, Garvan Institute of Medical Research, The Kinghorn Cancer Centre, Faculty of Medicine, St Vincent's Clinical School, University of New South Wales, Darlinghurst, New South Wales 2010, Australia
| | - Boris Macek
- Proteome Center Tuebingen, Interfaculty Institute for Cell Biology, University of Tuebingen, Tuebingen 72026, Germany
| | - Angeliki Malliri
- Cell Signalling Group, Cancer Research UK Manchester Institute, The University of Manchester, Manchester M204BX, UK
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22
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Xu K, Tian X, Oh SY, Movassaghi M, Naber SP, Kuperwasser C, Buchsbaum RJ. The fibroblast Tiam1-osteopontin pathway modulates breast cancer invasion and metastasis. Breast Cancer Res 2016; 18:14. [PMID: 26821678 PMCID: PMC4730665 DOI: 10.1186/s13058-016-0674-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 12/30/2015] [Indexed: 12/21/2022] Open
Abstract
Background The tumor microenvironment has complex effects in cancer pathophysiology that are not fully understood. Most cancer therapies are directed against malignant cells specifically, leaving pro-malignant signals from the microenvironment unaddressed. Defining specific mechanisms by which the tumor microenvironment contributes to breast cancer metastasis may lead to new therapeutic approaches against advanced breast cancer. Methods We use a novel method for manipulating three-dimensional mixed cell co-cultures, along with studies in mouse xenograft models of human breast cancer and a histologic study of human breast cancer samples, to investigate how breast cancer-associated fibroblasts affect the malignant behaviors of breast cancer cells. Results Altering fibroblast Tiam1 expression induces changes in invasion, migration, epithelial-mesenchymal transition, and cancer stem cell characteristics in associated breast cancer cells. These changes are both dependent on fibroblast secretion of osteopontin and also long-lasting even after cancer cell dissociation from the fibroblasts, indicating a novel Tiam1-osteopontin pathway in breast cancer-associated fibroblasts. Notably, inhibition of fibroblast osteopontin with low doses of a novel small molecule prevents lung metastasis in a mouse model of human breast cancer metastasis. Moreover, fibroblast expression patterns of Tiam1 and osteopontin in human breast cancers show converse changes correlating with invasion, supporting the hypothesis that this pathway in tumor-associated fibroblasts regulates breast cancer invasiveness in human disease and is thus clinically relevant. Conclusions These findings suggest a new therapeutic paradigm for preventing breast cancer metastasis. Pro-malignant signals from the tumor microenvironment with long-lasting effects on associated cancer cells may perpetuate the metastatic potential of developing cancers. Inhibition of these microenvironment signals represents a new therapeutic strategy against cancer metastasis that enables targeting of stromal cells with less genetic plasticity than associated cancer cells and opens new avenues for investigation of novel therapeutic targets and agents. Electronic supplementary material The online version of this article (doi:10.1186/s13058-016-0674-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kun Xu
- Molecular Oncology Research Institute, Tufts Medical Center, 75 Kneeland Street, Boston, MA, 02111, USA.
| | - Xuejun Tian
- Department of Pathology, Tufts Medical Center, 800 Washington Street, Boston, MA, 02111, USA.
| | - Sun Y Oh
- Molecular Oncology Research Institute, Tufts Medical Center, 75 Kneeland Street, Boston, MA, 02111, USA. .,Department of Medicine, Tufts Medical Center, 800 Washington Street, Boston, MA, 02111, USA.
| | - Mohammad Movassaghi
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA.
| | - Stephen P Naber
- Department of Pathology, Tufts Medical Center, 800 Washington Street, Boston, MA, 02111, USA.
| | - Charlotte Kuperwasser
- Molecular Oncology Research Institute, Tufts Medical Center, 75 Kneeland Street, Boston, MA, 02111, USA. .,Developmental, Molecular, and Chemical Biology Department, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA, 02111, USA.
| | - Rachel J Buchsbaum
- Molecular Oncology Research Institute, Tufts Medical Center, 75 Kneeland Street, Boston, MA, 02111, USA. .,Department of Medicine, Tufts Medical Center, 800 Washington Street, Boston, MA, 02111, USA.
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Cheng W, Liu Y, Zuo Z, Yin X, Jiang B, Chen D, Peng C, Yang J. Biological effects of RNAi targeted inhibiting Tiam1 gene expression on cholangiocarcinoma cells. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2015; 8:15511-15526. [PMID: 26884821 PMCID: PMC4730034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Accepted: 11/22/2015] [Indexed: 06/05/2023]
Abstract
OBJECTIVE To investigate the characteristics of Tiam1 gene expression in human cholangiocarcinoma tissues and benign bile duct tissues, and to analyze the correlations between Tiam1 gene expression and the degree of tumor differentiation, invasive and metastatic abilities. To explore the effect of targeted inhibiting Tiam1 gene expression on proliferation and migration activity of human cholangiocarcinoma cells. METHODS Expression of Tiam1 in 83 cases of cholangiocarcinoma tissues and 25 cases of benign bile tissues was detected using immunohistochemistry. The clinical data of patients with cholangiocarcinoma were collected. The correlations between Tiam1 gene expression and the clinicopathologic features in patients with cholangiocarcinoma were analyzed. The human cholangiocarcinoma RBE cells were divided into 3 groups. Cells in experimental group and control group were respectively transfected with Tiam1 shRNA lentiviral vectors and negative shRNA lentiviral control vectors. Cells in blank group received no treatment. Real-time PCR endogenesis was used to verify Tiam1 gene expression. Cell cycle experiments and MTT assay were used to measure cell proliferation activity. Transwell test was used to detect cell migration activity. RESULTS The negative rate Tiam1 protein expression in cholangiocarcinoma tissues was significantly higher than that in benign bile tissues (P<0.001). Tiam1 protein expression in cholangiocarcinoma tissues had correlations with cholangiocarcinoma differentiation degree, TNM stage and lymph node metastasis (P<0.05), and had no significant correlations with gender, age and distant metastasis (P>0.05). Real-time PCR detection indicated that Tiam1 expression of experimental group was significantly lower than that in control group and blank group (P<0.05), demonstrating that Tiam1 shRNA was effective on Tiam1 gene silencing in RBE cells. Cell cycle experiment showed that the percentage of S phase in cell cycle in experimental group was lower than that in control group and blank group (P<0.05), demonstrating that after the down-regulation of Tiam1 gene expression, the speed of cell proliferation was inhibited. MTT assay results showed that the total growth speed in experimental group was significantly lower than that in control group and blank group (P<0.05), indicating that the proliferation activity of cholangiocarcinoma cells was inhibited after targeted inhibition of Tiam1 gene expression. Transwell detection results showed that the metastasis rate in experimental group was significantly lower than that in control group and blank group (P<0.05), demonstrating that targeted inhibition of Tiam1 gene expression could significantly inhibit migration ability of RBE cells. CONCLUSION Tiam1 expression significantly increased in cholangiocarcinoma tissues, and increased along with the degree of malignancy of cholangiocarcinoma. Targeted silencing Tiam1 expression could inhibit proliferation and migration activity of cholangiocarcinoma cells.
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Affiliation(s)
- Wei Cheng
- Department of Hepatobiliary Surgery, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal UniversityChangsha, Hunan, China
| | - Yaling Liu
- Department of Hepatobiliary Surgery, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal UniversityChangsha, Hunan, China
| | - Zhi Zuo
- Department of Hepatobiliary Surgery, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal UniversityChangsha, Hunan, China
| | - Xinmin Yin
- Department of Hepatobiliary Surgery, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal UniversityChangsha, Hunan, China
| | - Bo Jiang
- Department of Hepatobiliary Surgery, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal UniversityChangsha, Hunan, China
| | - Daojin Chen
- The Third Hospital of Central South UniversityChangsha, Hunan, China
| | - Chuang Peng
- Department of Hepatobiliary Surgery, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal UniversityChangsha, Hunan, China
| | - Jianhui Yang
- Department of Hepatobiliary Surgery, Hunan Provincial People’s Hospital, The First Affiliated Hospital of Hunan Normal UniversityChangsha, Hunan, China
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Kang J, Park H, Kim E. IRSp53/BAIAP2 in dendritic spine development, NMDA receptor regulation, and psychiatric disorders. Neuropharmacology 2015; 100:27-39. [PMID: 26275848 DOI: 10.1016/j.neuropharm.2015.06.019] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 06/26/2015] [Accepted: 06/28/2015] [Indexed: 01/08/2023]
Abstract
IRSp53 (also known as BAIAP2) is a multi-domain scaffolding and adaptor protein that has been implicated in the regulation of membrane and actin dynamics at subcellular structures, including filopodia and lamellipodia. Accumulating evidence indicates that IRSp53 is an abundant component of the postsynaptic density at excitatory synapses and an important regulator of actin-rich dendritic spines. In addition, IRSp53 has been implicated in diverse psychiatric disorders, including autism spectrum disorders, schizophrenia, and attention deficit/hyperactivity disorder. Mice lacking IRSp53 display enhanced NMDA (N-methyl-d-aspartate) receptor function accompanied by social and cognitive deficits, which are reversed by pharmacological suppression of NMDA receptor function. These results suggest the hypothesis that defective actin/membrane modulation in IRSp53-deficient dendritic spines may lead to social and cognitive deficits through NMDA receptor dysfunction. This article is part of the Special Issue entitled 'Synaptopathy--from Biology to Therapy'.
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Affiliation(s)
- Jaeseung Kang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, South Korea
| | - Haram Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, South Korea
| | - Eunjoon Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, South Korea; Center for Synaptic Brain Dysfunctions, Institute for Basic Science (IBS), Daejeon 305-701, South Korea.
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Abstract
BAR proteins comprise a heterogeneous group of multi-domain proteins with diverse biological functions. The common denominator is the Bin-Amphiphysin-Rvs (BAR) domain that not only confers targeting to lipid bilayers, but also provides scaffolding to mold lipid membranes into concave or convex surfaces. This function of BAR proteins is an important determinant in the dynamic reconstruction of membrane vesicles, as well as of the plasma membrane. Several BAR proteins function as linkers between cytoskeletal regulation and membrane dynamics. These links are provided by direct interactions between BAR proteins and actin-nucleation-promoting factors of the Wiskott-Aldrich syndrome protein family and the Diaphanous-related formins. The Rho GTPases are key factors for orchestration of this intricate interplay. This review describes how BAR proteins regulate the activity of Rho GTPases, as well as how Rho GTPases regulate the function of BAR proteins. This mutual collaboration is a central factor in the regulation of vital cellular processes, such as cell migration, cytokinesis, intracellular transport, endocytosis, and exocytosis.
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Affiliation(s)
- Pontus Aspenström
- a Department of Microbiology and Tumor and Cell Biology; Karolinska Institutet ; Stockholm , Sweden
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26
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Visanji NP, Kamali Sarvestani I, Creed MC, Shams Shoaei Z, Nobrega JN, Hamani C, Hazrati LN. Deep brain stimulation of the subthalamic nucleus preferentially alters the translational profile of striatopallidal neurons in an animal model of Parkinson's disease. Front Cell Neurosci 2015; 9:221. [PMID: 26106299 PMCID: PMC4460554 DOI: 10.3389/fncel.2015.00221] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 05/25/2015] [Indexed: 01/17/2023] Open
Abstract
Deep brain stimulation targeting the subthalamic nucleus (STN-DBS) is an effective surgical treatment for the motor symptoms of Parkinson's disease (PD), the precise neuronal mechanisms of which both at molecular and network levels remain a topic of debate. Here we employ two transgenic mouse lines, combining translating ribosomal affinity purification (TRAP) with bacterial artificial chromosome expression (Bac), to selectively identify changes in translational gene expression in either Drd1a-expressing striatonigral or Drd2-expressing striatopallidal medium spiny neurons (MSNs) of the striatum following STN-DBS. 6-hydroxydopamine lesioned mice received either 5 days stimulation via a DBS electrode implanted in the ipsilateral STN or 5 days sham treatment (no stimulation). Striatal polyribosomal RNA was selectively purified from either Drd2 or Drd1a MSNs using the TRAP method and gene expression profiling performed. We identified eight significantly altered genes in Drd2 MSNs (Vps33b, Ppp1r3c, Mapk4, Sorcs2, Neto1, Abca1, Penk1, and Gapdh) and two overlapping genes in Drd1a MSNs (Penk1 and Ppp1r3c) implicated in the molecular mechanisms of STN-DBS. A detailed functional analysis, using a further 728 probes implicated in STN-DBS, suggested an increased ability to receive excitation (mediated by increased dendritic spines, increased calcium influx and enhanced excitatory post synaptic potentials) accompanied by processes that would hamper the initiation of action potentials, transport of neurotransmitters from soma to axon terminals and vesicular release in Drd2-expressing MSNs. Finally, changes in expression of several genes involved in apoptosis as well as cholesterol and fatty acid metabolism were also identified. This increased understanding of the molecular mechanisms induced by STN-DBS may reveal novel targets for future non-surgical therapies for PD.
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Affiliation(s)
- Naomi P Visanji
- Morton and Gloria Shulman Movement Disorders Centre and the Edmund J. Safra Program in Parkinson's disease, Toronto Western Hospital Toronto, ON, Canada
| | - Iman Kamali Sarvestani
- Faculty of Medicine, Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto Toronto, ON, Canada ; Department of Neuroscience, Stockholm Brain Institute, Karolinska Institute Stockholm, Sweden
| | - Meaghan C Creed
- Behavioural Neurobiology Laboratory, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health Toronto, ON, Canada
| | - Zahra Shams Shoaei
- Faculty of Medicine, Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto Toronto, ON, Canada
| | - José N Nobrega
- Behavioural Neurobiology Laboratory, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health Toronto, ON, Canada
| | - Clement Hamani
- Behavioural Neurobiology Laboratory, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health Toronto, ON, Canada ; Division of Neurosurgery, Toronto Western Hospital, University of Toronto Toronto, ON, Canada
| | - Lili-Naz Hazrati
- Faculty of Medicine, Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto Toronto, ON, Canada
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Duman JG, Mulherkar S, Tu YK, X Cheng J, Tolias KF. Mechanisms for spatiotemporal regulation of Rho-GTPase signaling at synapses. Neurosci Lett 2015; 601:4-10. [PMID: 26003445 DOI: 10.1016/j.neulet.2015.05.034] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 05/16/2015] [Accepted: 05/18/2015] [Indexed: 01/16/2023]
Abstract
Synapses mediate information flow between neurons and undergo plastic changes in response to experience, which is critical for learning and memory. Conversely, synaptic defects impair information processing and underlie many brain pathologies. Rho-family GTPases control synaptogenesis by transducing signals from extracellular stimuli to the cytoskeleton and nucleus. The Rho-GTPases Rac1 and Cdc42 promote synapse development and the growth of axons and dendrites, while RhoA antagonizes these processes. Despite its importance, many aspects of Rho-GTPase signaling remain relatively unknown. Rho-GTPases are activated by guanine nucleotide exchange factors (GEFs) and inhibited by GTPase-activating proteins (GAPs). Though the number of both GEFs and GAPs greatly exceeds that of Rho-GTPases, loss of even a single GEF or GAP often has profound effects on cognition and behavior. Here, we explore how the actions of specific GEFs and GAPs give rise to the precise spatiotemporal activation patterns of Rho-GTPases in neurons. We consider the effects of coupling GEFs and GAPs targeting the same Rho-GTPase and the modular pathways that connect specific cellular stimuli with a given Rho-GTPase via different GEFs. We discuss how the creation of sharp borders between Rho-GTPase activation zones is achieved by pairing a GEF for one Rho-GTPase with a GAP for another and the extensive crosstalk between different Rho-GTPases. Given the importance of synapses for cognition and the fundamental roles that Rho-GTPases play in regulating them, a detailed understanding of Rho-GTPase signaling is essential to the progress of neuroscience.
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Affiliation(s)
- Joseph G Duman
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Shalaka Mulherkar
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Yen-Kuei Tu
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Integrative Molecular and Biomedical Sciences Program,Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Jinxuan X Cheng
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Kimberley F Tolias
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Integrative Molecular and Biomedical Sciences Program,Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
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WANG SHUANG, LI SHISHENG, TANG QINGLAI, YANG SHU, WANG SHUHUI, LIU JIAJIA, YANG MI, YANG XINMING. Overexpression of Tiam1 promotes the progression of laryngeal squamous cell carcinoma. Oncol Rep 2015; 33:1807-14. [DOI: 10.3892/or.2015.3785] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 01/21/2015] [Indexed: 11/06/2022] Open
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Jin SX, Bartolome C, Arai JA, Hoffman L, Uzturk BG, Kumar-Singh R, Waxham MN, Feig LA. Domain contributions to signaling specificity differences between Ras-guanine nucleotide releasing factor (Ras-GRF) 1 and Ras-GRF2. J Biol Chem 2014; 289:16551-64. [PMID: 24755227 DOI: 10.1074/jbc.m114.557959] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ras-GRF1 (GRF1) and Ras-GRF2 (GRF2) constitute a family of similar calcium sensors that regulate synaptic plasticity. They are both guanine exchange factors that contain a very similar set of functional domains, including N-terminal pleckstrin homology, coiled-coil, and calmodulin-binding IQ domains and C-terminal Dbl homology Rac-activating domains, Ras-exchange motifs, and CDC25 Ras-activating domains. Nevertheless, they regulate different forms of synaptic plasticity. Although both GRF proteins transduce calcium signals emanating from NMDA-type glutamate receptors in the CA1 region of the hippocampus, GRF1 promotes LTD, whereas GRF2 promotes θ-burst stimulation-induced LTP (TBS-LTP). GRF1 can also mediate high frequency stimulation-induced LTP (HFS-LTP) in mice over 2-months of age, which involves calcium-permeable AMPA-type glutamate receptors. To add to our understanding of how proteins with similar domains can have different functions, WT and various chimeras between GRF1 and GRF2 proteins were tested for their abilities to reconstitute defective LTP and/or LTD in the CA1 hippocampus of Grf1/Grf2 double knock-out mice. These studies revealed a critical role for the GRF2 CDC25 domain in the induction of TBS-LTP by GRF proteins. In contrast, the N-terminal pleckstrin homology and/or coiled-coil domains of GRF1 are key to the induction of HFS-LTP by GRF proteins. Finally, the IQ motif of GRF1 determines whether a GRF protein can induce LTD. Overall, these findings show that for the three forms of synaptic plasticity that are regulated by GRF proteins in the CA1 hippocampus, specificity is encoded in only one or two domains, and a different set of domains for each form of synaptic plasticity.
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Affiliation(s)
- Shan-Xue Jin
- From the Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts 02111 and
| | - Christopher Bartolome
- From the Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts 02111 and
| | - Junko A Arai
- From the Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts 02111 and
| | - Laurel Hoffman
- the Department of Neurobiology and Anatomy, University of Texas, Houston, Texas
| | - B Gizem Uzturk
- From the Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts 02111 and
| | - Rajendra Kumar-Singh
- From the Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts 02111 and
| | - M Neal Waxham
- the Department of Neurobiology and Anatomy, University of Texas, Houston, Texas
| | - Larry A Feig
- From the Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, Massachusetts 02111 and
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30
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Kast DJ, Yang C, Disanza A, Boczkowska M, Madasu Y, Scita G, Svitkina T, Dominguez R. Mechanism of IRSp53 inhibition and combinatorial activation by Cdc42 and downstream effectors. Nat Struct Mol Biol 2014; 21:413-22. [PMID: 24584464 DOI: 10.1038/nsmb.2781] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 01/28/2014] [Indexed: 12/16/2022]
Abstract
The Rho family GTPase effector IRSp53 has essential roles in filopodia formation and neuronal development, but its regulatory mechanism is poorly understood. IRSp53 contains a membrane-binding BAR domain followed by an unconventional CRIB motif that overlaps with a proline-rich region (CRIB-PR) and an SH3 domain that recruits actin cytoskeleton effectors. Using a fluorescence reporter assay, we show that human IRSp53 adopts a closed inactive conformation that opens synergistically with the binding of human Cdc42 to the CRIB-PR and effector proteins, such as the tumor-promoting factor Eps8, to the SH3 domain. The crystal structure of Cdc42 bound to the CRIB-PR reveals a new mode of effector binding to Rho family GTPases. Structure-inspired mutations disrupt autoinhibition and Cdc42 binding in vitro and decouple Cdc42- and IRSp53-dependent filopodia formation in cells. The data support a combinatorial mechanism of IRSp53 activation.
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Affiliation(s)
- David J Kast
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Changsong Yang
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | | | - Malgorzata Boczkowska
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yadaiah Madasu
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Giorgio Scita
- 1] FIRC Institute of Molecular Oncology, Milan, Italy. [2] Department of Health Sciences, University of Milan School of Medicine, Milan, Italy
| | - Tatyana Svitkina
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Roberto Dominguez
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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31
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Lőrincz ÁM, Szarvas G, Smith SME, Ligeti E. Role of Rac GTPase activating proteins in regulation of NADPH oxidase in human neutrophils. Free Radic Biol Med 2014; 68:65-71. [PMID: 24321316 DOI: 10.1016/j.freeradbiomed.2013.12.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 11/15/2013] [Accepted: 12/01/2013] [Indexed: 10/25/2022]
Abstract
Precise spatiotemporal regulation of O2(-)-generating NADPH oxidases (Nox) is a vital requirement. In the case of Nox1-3, which depend on the small GTPase Rac, acceleration of GTP hydrolysis by GTPase activating protein (GAP) could represent a feasible temporal control mechanism. Our goal was to investigate the molecular interactions between RacGAPs and phagocytic Nox2 in neutrophilic granulocytes. In structural studies we revealed that simultaneous interaction of Rac with its effector protein p67(phox) and regulatory protein RacGAP was sterically possible. The effect of RacGAPs was experimentally investigated in a cell-free O2(-)-generating system consisting of isolated membranes and recombinant p47(phox) and p67(phox) proteins. Addition of soluble RacGAPs decreased O2(-) production and there was no difference in the effect of four RacGAPs previously identified in neutrophils. Depletion of membrane-associated RacGAPs had a selective effect: a decrease in ARHGAP1 or ARHGAP25 level increased O2(-) production but a depletion of ARHGAP35 had no effect. Only membrane-localized RacGAPs seem to be able to interact with Rac when it is assembled in the Nox2 complex. Thus, in neutrophils multiple RacGAPs are involved in the control of O2(-) production by Nox2, allowing selective regulation via different signaling pathways.
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Affiliation(s)
- Ákos M Lőrincz
- Department of Physiology, Semmelweis University, Tűzoltó u. 37-47, 1094 Budapest, Hungary
| | - Gábor Szarvas
- Department of Physiology, Semmelweis University, Tűzoltó u. 37-47, 1094 Budapest, Hungary
| | - Susan M E Smith
- Department of Biology and Physics, Kennesaw State University, 1000 Chastain Road, Building 12, Room 308, Kennesaw, GA 30144, USA
| | - Erzsébet Ligeti
- Department of Physiology, Semmelweis University, Tűzoltó u. 37-47, 1094 Budapest, Hungary.
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32
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The guanine nucleotide exchange factor Tiam1: A Janus-faced molecule in cellular signaling. Cell Signal 2014; 26:483-91. [DOI: 10.1016/j.cellsig.2013.11.034] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 11/26/2013] [Indexed: 11/22/2022]
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33
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Wang S, Li S, Yang X, Yang S, Liu S, Liu B, Liu J. Elevated expression of T-lymphoma invasion and metastasis inducing factor 1 in squamous-cell carcinoma of the head and neck and its clinical significance. Eur J Cancer 2013; 50:379-87. [PMID: 24189000 DOI: 10.1016/j.ejca.2013.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 07/28/2013] [Accepted: 10/03/2013] [Indexed: 12/17/2022]
Abstract
PURPOSE T-lymphoma invasion and metastasis inducing factor 1 (Tiam1) overexpression has been reported in a variety of human cancers. However, the investigation of Tiam1 in squamous-cell carcinoma of the head and neck (SCCHN) is extremely rare. The aim of the present study is to assess Tiam1 expression and to explore its role in SCCHN. METHODS Tiam1 expression in 119 primary SCCHN tissue specimens was analysed by immunohistochemistry and correlated with clinicopathological parameters and patients' survival. Additionally, 12 paired SCCHN tissues were evaluated for Tiam1 expression by Western blotting. RESULTS Western blotting indicated that Tiam1 expression levels in SCCHN carcinomas were significantly higher than those in the corresponding paraneoplastic tissues (P<0.001). Immmunohistochemistry staining revealed that Tiam1 was detected in all primary tumour samples, moreover, Tiam1 overexpression was significantly correlated with lymph node metastasis (P<0.001), clinical stage (P<0.001), histological grade (P=0.001) and recurrence (P<0.001). Survival analysis demonstrated that high Tiam1 expression was significantly correlated with shorter disease-free survival and overall survival (both P<0.001). When combining the Tiam1 expression and lymph node status, Kaplan-Meier survival showed that patients with Tiam1 overexpression/lymph node metastasis (+) had both shorter disease-free and overall survival than others (both P<0.001). Multivariate Cox proportional hazards model analysis confirmed that lymph node metastasis, histological grade and Tiam1 overexpression were statistically significant, independent predictor of prognosis for patients with SCCHN. CONCLUSION Tiam1 may contribute to SCCHN progression, and represent as a novel prognostic indicator as well as a potential therapeutic target for SCCHN.
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Affiliation(s)
- Shuang Wang
- Department of Otolaryngology-Head and Neck Surgery, The Second Xiangya Hospital, Central South University, 139 Renmin Road, Changsha 410011, Hunan, PR China
| | - Shisheng Li
- Department of Otolaryngology-Head and Neck Surgery, The Second Xiangya Hospital, Central South University, 139 Renmin Road, Changsha 410011, Hunan, PR China
| | - Xinming Yang
- Department of Otolaryngology-Head and Neck Surgery, The Second Xiangya Hospital, Central South University, 139 Renmin Road, Changsha 410011, Hunan, PR China.
| | - Shu Yang
- Department of Otolaryngology-Head and Neck Surgery, The Second Xiangya Hospital, Central South University, 139 Renmin Road, Changsha 410011, Hunan, PR China
| | - Shuhua Liu
- Department of Otolaryngology-Head and Neck Surgery, The Second Xiangya Hospital, Central South University, 139 Renmin Road, Changsha 410011, Hunan, PR China
| | - Bingbing Liu
- Department of Otolaryngology-Head and Neck Surgery, The Second Xiangya Hospital, Central South University, 139 Renmin Road, Changsha 410011, Hunan, PR China
| | - Jiajia Liu
- Department of Otolaryngology-Head and Neck Surgery, The Second Xiangya Hospital, Central South University, 139 Renmin Road, Changsha 410011, Hunan, PR China
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Subramanian N, Navaneethakrishnan S, Biswas J, Kanwar RK, Kanwar JR, Krishnakumar S. RNAi mediated Tiam1 gene knockdown inhibits invasion of retinoblastoma. PLoS One 2013; 8:e70422. [PMID: 23950931 PMCID: PMC3737373 DOI: 10.1371/journal.pone.0070422] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2013] [Accepted: 06/18/2013] [Indexed: 11/18/2022] Open
Abstract
T lymphoma invasion and metastasis protein (Tiam1) is up-regulated in variety of cancers and its expression level is related to metastatic potential of the type of cancer. Earlier, Tiam1 was shown to be overexpressed in retinoblastoma (RB) and we hypothesized that it was involved in invasiveness of RB. This was tested by silencing Tiam1 in RB cell lines (Y79 and Weri-Rb1) using siRNA pool, targeting different regions of Tiam1 mRNA. The cDNA microarray of Tiam1 silenced cells showed gene regulations altered by Tiam1 were predominantly on the actin cytoskeleton interacting proteins, apoptotic initiators and tumorogenic potential targets. The silenced phenotype resulted in decreased growth and increased apoptosis with non-invasive characteristics. Transfection of full length and N-terminal truncated construct (C1199) clearly revealed membrane localization of Tiam1 and not in the case of C580 construct. F-actin staining showed the interaction of Tiam1 with actin in the membrane edges that leads to ruffling, and also imparts varying invasive potential to the cell. The results obtained from our study show for the first time that Tiam1 modulates the cell invasion, mediated by actin cytoskeleton remodeling in RB.
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Affiliation(s)
- Nithya Subramanian
- Larsen and Toubro Department of Ocular Pathology, Vision Research Foundation, Sankara Nethralaya, Chennai, India
- Nanomedicine Laboratory of Immunology and Molecular Biomedical Research (N-LIMBR), School of Medicine (SoM), Molecular and Medical Research (MMR) Strategic Research Centre, Faculty of Health, Deakin University, Geelong Technology Precinct (GTP), Geelong, Victoria, Australia
| | - Saranya Navaneethakrishnan
- Larsen and Toubro Department of Ocular Pathology, Vision Research Foundation, Sankara Nethralaya, Chennai, India
| | - Jyotirmay Biswas
- Larsen and Toubro Department of Ocular Pathology, Vision Research Foundation, Sankara Nethralaya, Chennai, India
| | - Rupinder K. Kanwar
- Nanomedicine Laboratory of Immunology and Molecular Biomedical Research (N-LIMBR), School of Medicine (SoM), Molecular and Medical Research (MMR) Strategic Research Centre, Faculty of Health, Deakin University, Geelong Technology Precinct (GTP), Geelong, Victoria, Australia
| | - Jagat R. Kanwar
- Nanomedicine Laboratory of Immunology and Molecular Biomedical Research (N-LIMBR), School of Medicine (SoM), Molecular and Medical Research (MMR) Strategic Research Centre, Faculty of Health, Deakin University, Geelong Technology Precinct (GTP), Geelong, Victoria, Australia
- * E-mail: (SK); (JRK)
| | - Subramanian Krishnakumar
- Larsen and Toubro Department of Ocular Pathology, Vision Research Foundation, Sankara Nethralaya, Chennai, India
- * E-mail: (SK); (JRK)
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35
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Panja D, Bramham CR. BDNF mechanisms in late LTP formation: A synthesis and breakdown. Neuropharmacology 2013; 76 Pt C:664-76. [PMID: 23831365 DOI: 10.1016/j.neuropharm.2013.06.024] [Citation(s) in RCA: 228] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Revised: 06/21/2013] [Accepted: 06/23/2013] [Indexed: 12/12/2022]
Abstract
Unraveling the molecular mechanisms governing long-term synaptic plasticity is a key to understanding how the brain stores information in neural circuits and adapts to a changing environment. Brain-derived neurotrophic factor (BDNF) has emerged as a regulator of stable, late phase long-term potentiation (L-LTP) at excitatory glutamatergic synapses in the adult brain. However, the mechanisms by which BDNF triggers L-LTP are controversial. Here, we distill and discuss the latest advances along three main lines: 1) TrkB receptor-coupled translational control underlying dendritic protein synthesis and L-LTP, 2) Mechanisms for BDNF-induced rescue of L-LTP when protein synthesis is blocked, and 3) BDNF-TrkB regulation of actin cytoskeletal dynamics in dendritic spines. Finally, we explore the inter-relationships between BDNF-regulated mechanisms, how these mechanisms contribute to different forms of L-LTP in the hippocampus and dentate gyrus, and outline outstanding issues for future research. This article is part of the Special Issue entitled 'BDNF Regulation of Synaptic Structure, Function, and Plasticity'.
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Affiliation(s)
- Debabrata Panja
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway; KG Jebsen Centre for Research on Neuropsychiatric Disorders, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway
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36
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Joshi M, Gakhar L, Fuentes EJ. High-resolution structure of the Tiam1 PHn-CC-Ex domain. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:744-52. [PMID: 23832200 PMCID: PMC3702317 DOI: 10.1107/s1744309113014206] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 05/22/2013] [Indexed: 01/22/2023]
Abstract
The T-lymphoma and metastasis gene 1 (TIAM1) encodes a guanine nucleotide-exchange factor protein (Tiam1) that is specific for the Rho-family GTPase Rac1 and is important for cell polarity, migration and adhesion. Tiam1 is a large multi-domain protein that contains several protein-protein binding domains that are important for regulating cellular function. The PHn-CC-Ex domain is critical for plasma-membrane association and interactions with protein-scaffold proteins (e.g. Par3b, spinophilin, IRSp53 and JIP2) that direct Tiam1-Rac1 signaling specificity. It was determined that the coiled-coil domain of Par3b binds the PHn-CC-Ex domain with a dissociation constant of ≈ 30 µM. Moreover, the structures of two variants of the Tiam1 PHn-CC-Ex domain were solved at resolutions of 1.98 and 2.15 Å, respectively. The structures indicate that the PHn, CC and Ex regions form independent subdomains that together provide an integrated platform for binding partner proteins. Small-angle X-ray scattering (SAXS) data indicate that the Tiam1 PHn-CC-Ex domain is monomeric in solution and that the solution and crystal structures are very similar. Together, these data provide the foundation necessary to elucidate the structural mechanism of the PHn-CC-Ex/scaffold interactions that are critical for Tiam1-Rac1 signaling specificity.
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Affiliation(s)
- Monika Joshi
- Department of Biochemistry, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Lokesh Gakhar
- Department of Biochemistry, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
- Protein Crystallography Facility, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
| | - Ernesto J. Fuentes
- Department of Biochemistry, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
- Holden Comprehensive Cancer Center, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1109, USA
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The adhesion-GPCR BAI1 regulates synaptogenesis by controlling the recruitment of the Par3/Tiam1 polarity complex to synaptic sites. J Neurosci 2013; 33:6964-78. [PMID: 23595754 DOI: 10.1523/jneurosci.3978-12.2013] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Excitatory synapses are polarized structures that primarily reside on dendritic spines in the brain. The small GTPase Rac1 regulates the development and plasticity of synapses and spines by modulating actin dynamics. By restricting the Rac1-guanine nucleotide exchange factor Tiam1 to spines, the polarity protein Par3 promotes synapse development by spatially controlling Rac1 activation. However, the mechanism for recruiting Par3 to spines is unknown. Here, we identify brain-specific angiogenesis inhibitor 1 (BAI1) as a synaptic adhesion GPCR that is required for spinogenesis and synaptogenesis in mice and rats. We show that BAI1 interacts with Par3/Tiam1 and recruits these proteins to synaptic sites. BAI1 knockdown results in Par3/Tiam1 mislocalization and loss of activated Rac1 and filamentous actin from spines. Interestingly, BAI1 also mediates Rac-dependent engulfment in professional phagocytes through its interaction with a different Rac1-guanine nucleotide exchange factor module, ELMO/DOCK180. However, this interaction is dispensable for BAI1's role in synapse development because a BAI1 mutant that cannot interact with ELMO/DOCK180 rescues spine defects in BAI1-knockdown neurons, whereas a mutant that cannot interact with Par3/Tiam1 rescues neither spine defects nor Par3 localization. Further, overexpression of Tiam1 rescues BAI1 knockdown spine phenotypes. These results indicate that BAI1 plays an important role in synaptogenesis that is mechanistically distinct from its role in phagocytosis. Furthermore, our results provide the first example of a cell surface receptor that targets members of the PAR polarity complex to synapses.
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Jin SX, Arai J, Tian X, Kumar-Singh R, Feig LA. Acquisition of contextual discrimination involves the appearance of a RAS-GRF1/p38 mitogen-activated protein (MAP) kinase-mediated signaling pathway that promotes long term potentiation (LTP). J Biol Chem 2013; 288:21703-13. [PMID: 23766509 DOI: 10.1074/jbc.m113.471904] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
RAS-GRF1 is a guanine nucleotide exchange factor with the ability to activate RAS and RAC GTPases in response to elevated calcium levels. We previously showed that beginning at 1 month of age, RAS-GRF1 mediates NMDA-type glutamate receptor (NMDAR)-induction of long term depression in the CA1 region of the hippocampus of mice. Here we show that beginning at 2 months of age, when mice first acquire the ability to discriminate between closely related contexts, RAS-GRF1 begins to contribute to the induction of long term potentiation (LTP) in the CA1 hippocampus by mediating the action of calcium-permeable, AMPA-type glutamate receptors (CP-AMPARs). Surprisingly, LTP induction by CP-AMPARs through RAS-GRF1 occurs via activation of p38 MAP kinase rather than ERK MAP kinase, which has more frequently been linked to LTP. Moreover, contextual discrimination is blocked by knockdown of Ras-Grf1 expression specifically in the CA1 hippocampus, infusion of a p38 MAP kinase inhibitor into the CA1 hippocampus, or the injection of an inhibitor of CP-AMPARs. These findings implicate the CA1 hippocampus in the developmentally dependent capacity to distinguish closely related contexts through the appearance of a novel LTP-supporting signaling pathway.
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Affiliation(s)
- Shan-Xue Jin
- Department of Biochemistry, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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39
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Lewis-Saravalli S, Campbell S, Claing A. ARF1 controls Rac1 signaling to regulate migration of MDA-MB-231 invasive breast cancer cells. Cell Signal 2013; 25:1813-9. [PMID: 23707487 DOI: 10.1016/j.cellsig.2013.05.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 05/07/2013] [Indexed: 12/19/2022]
Abstract
ADP-ribosylation factors (ARFs) are monomeric G proteins that regulate many cellular processes such as reorganization of the actin cytoskeleton. We have previously shown that ARF1 is overexpressed in highly invasive breast cancer cells and contribute to their enhanced migration. In this study, we propose to define the molecular mechanism by which ARF1 regulates this complex cellular response by investigating the role of this ARF GTPase on the activation process of Rac1, a Rho GTPase, associated with lamellipodia formation during cell migration. Here, we first show that inhibition of ARF1 or Rac1 expression markedly impacts the ability of MDA-MB-231 cells to migrate upon EGF stimulation. However, the effect of ARF1 depletion can be reversed by overexpression of the Rac1 active mutant, Rac1 Q(61)L. Depletion of ARF1 also impairs the ability of EGF stimulation to promote GTP-loading of Rac1. To further investigate the possible cross-talk between ARF1 and Rac1, we next examined whether they could form a complex. We observed that the two GTPases could directly interact independently of the nature of the nucleotide bound to them. EGF treatment however resulted in the association of Rac1 with its effector IRSp53, which was completely abrogated in ARF1 depleted cells. We present evidences that this ARF isoform is responsible for the plasma membrane targeting of both Rac1 and IRSp53, a step essential for lamellipodia formation. In conclusion, this study provides a new mechanism by which ARF1 regulates cell migration and identifies this GTPase as a promising pharmacological target to reduce metastasis formation in breast cancer patients.
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Affiliation(s)
- Sebastian Lewis-Saravalli
- Department of Pharmacology, Faculty of Medicine, Université de Montréal, Montreal, QC H3C 3J7, Canada
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40
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Abstract
Small GTPases use GDP/GTP alternation to actuate a variety of functional switches that are pivotal for cell dynamics. The GTPase switch is turned on by GEFs, which stimulate dissociation of the tightly bound GDP, and turned off by GAPs, which accelerate the intrinsically sluggish hydrolysis of GTP. For Ras, Rho, and Rab GTPases, this switch incorporates a membrane/cytosol alternation regulated by GDIs and GDI-like proteins. The structures and core mechanisms of representative members of small GTPase regulators from most families have now been elucidated, illuminating their general traits combined with scores of unique features. Recent studies reveal that small GTPase regulators have themselves unexpectedly sophisticated regulatory mechanisms, by which they process cellular signals and build up specific cell responses. These mechanisms include multilayered autoinhibition with stepwise release, feedback loops mediated by the activated GTPase, feed-forward signaling flow between regulators and effectors, and a phosphorylation code for RhoGDIs. The flipside of these highly integrated functions is that they make small GTPase regulators susceptible to biochemical abnormalities that are directly correlated with diseases, notably a striking number of missense mutations in congenital diseases, and susceptible to bacterial mimics of GEFs, GAPs, and GDIs that take command of small GTPases in infections. This review presents an overview of the current knowledge of these many facets of small GTPase regulation.
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Affiliation(s)
- Jacqueline Cherfils
- Laboratoire d’Enzymologie et Biochimie Structurales, Centre National de la Recherche Scientifique, Centre deRecherche de Gif, Gif-sur-Yvette, France
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41
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Mitin N, Rossman KL, Der CJ. Identification of a novel actin-binding domain within the Rho guanine nucleotide exchange factor TEM4. PLoS One 2012; 7:e41876. [PMID: 22911862 PMCID: PMC3404065 DOI: 10.1371/journal.pone.0041876] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 06/27/2012] [Indexed: 11/19/2022] Open
Abstract
Spatio-temporal activation of Rho GTPases is essential for their function in a variety of biological processes and is achieved in part by regulating the localization of their activators, the Rho guanine nucleotide exchange factors (RhoGEFs). In this study, we provide the first characterization of the full-length protein encoded by RhoGEF TEM4 and delineate its domain structure, catalytic activity, and subcellular localization. First, we determined that TEM4 can stimulate guanine nucleotide exchange on RhoA and the related RhoB and RhoC isoforms. Second, we determined that TEM4, like other Dbl RhoGEFs, contains a functional pleckstrin homology (PH) domain immediately C-terminal to the catalytic Dbl homology (DH) domain. Third, using immunofluorescence analysis, we showed that TEM4 localizes to the actin cytoskeleton through sequences in the N-terminus of TEM4 independently of the DH/PH domains. Using site-directed mutagenesis and deletion analysis, we identified a minimal region between residues 81 and 135 that binds directly to F-actin and has an ∼90-fold higher affinity for ATP-loaded F-actin. Finally, we demonstrated that a single point mutation (R130D) within full-length TEM4 abolishes actin binding and localization of TEM4 to the actin cytoskeleton, as well as dampens the in vivo activity of TEM4 towards RhoC. Taken together, our data demonstrate that TEM4 contains a novel actin binding domain and binding to actin is essential for TEM4 subcellular localization and activity. The unique subcellular localization of TEM4 suggests a spatially-restricted activity and expands the diversity of mechanisms by which RhoGEF function can be regulated.
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Affiliation(s)
- Natalia Mitin
- Lineberger Comprehensive Cancer Center and Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America.
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42
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Csépányi-Kömi R, Lévay M, Ligeti E. Small G proteins and their regulators in cellular signalling. Mol Cell Endocrinol 2012; 353:10-20. [PMID: 22108439 DOI: 10.1016/j.mce.2011.11.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 09/27/2011] [Accepted: 11/07/2011] [Indexed: 01/04/2023]
Abstract
Small molecular weight GTPases (small G proteins) are essential in the transduction of signals from different plasma membrane receptors. Due to their endogenous GTP-hydrolyzing activity, these proteins function as time-dependent biological switches controlling diverse cellular functions including cell shape and migration, cell proliferation, gene transcription, vesicular transport and membrane-trafficking. This review focuses on endocrine diseases linked to small G proteins. We provide examples for the regulation of the activity of small G proteins by various mechanisms such as posttranslational modifications, guanine nucleotide exchange factors (GEFs), GTPase activating proteins (GAPs) or guanine nucleotide dissociation inhibitors (GDIs). Finally we summarize endocrine diseases where small G proteins or their regulatory proteins have been revealed as the cause.
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Affiliation(s)
- Roland Csépányi-Kömi
- Department of Physiology, Semmelweis University, Tűzoltó u. 37-47, 1094 Budapest, Hungary
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43
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Krause SA, Cundell MJ, Poon PP, McGhie J, Johnston GC, Price C, Gray JV. Functional specialisation of yeast Rho1 GTP exchange factors. J Cell Sci 2012; 125:2721-31. [PMID: 22344253 DOI: 10.1242/jcs.100685] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rho GTPases are regulated in complex spatiotemporal patterns that might be dependent, in part at least, on the multiplicity of their GTP exchange factors (GEFs). Here, we examine the extent of and basis for functional specialisation of the Rom2 and Tus1 GEFs that activate the yeast Rho1 GTPase, the orthologue of mammalian RhoA. First, we find that these GEFs selectively activate different Rho1-effector branches. Second, the synthetic genetic networks around ROM2 and TUS1 confirm very different global in vivo roles for these GEFs. Third, the GEFs are not functionally interchangeable: Tus1 cannot replace the essential role of Rom2, even when overexpressed. Fourth, we find that Rom2 and Tus1 localise differently: Rom2 to the growing bud surface and to the bud neck at cytokinesis; Tus1 only to the bud neck, but in a distinct pattern. Finally, we find that these GEFs are dependent on different protein co-factors: Rom2 function and localisation is largely dependent on Ack1, a SEL1-domain-containing protein; Tus1 function and localisation is largely dependent on the Tus1-interacting protein Ypl066w (which we name Rgl1). We have revealed a surprising level of diversity among the Rho1 GEFs that contributes another level of complexity to the spatiotemporal control of Rho1.
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Affiliation(s)
- Sue Ann Krause
- School of Life Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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Liu J, Xu K, Chase M, Ji Y, Logan JK, Buchsbaum RJ. Tiam1-regulated osteopontin in senescent fibroblasts contributes to the migration and invasion of associated epithelial cells. J Cell Sci 2012; 125:376-86. [PMID: 22302986 DOI: 10.1242/jcs.089466] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The tumor microenvironment undergoes changes concurrent with neoplastic progression. Cancer incidence increases with aging and is associated with tissue accumulation of senescent cells. Senescent fibroblasts are thought to contribute to tumor development in aging tissues. We have shown that fibroblasts deficient in the Rac exchange factor Tiam1 promote invasion and metastasis of associated epithelial tumor cells. Here, we use a three-dimensional culture model of cellular invasiveness to outline several steps underlying this effect. We find that stress-induced senescence induces decreased fibroblast Tiam1 protein levels and increased osteopontin levels, and that senescent fibroblast lysates induce Tiam1 protein degradation in a calcium- and calpain-dependent fashion. Changes in fibroblast Tiam1 protein levels induce converse changes in osteopontin mRNA and protein. Senescent fibroblasts induce increased invasion and migration in co-cultured mammary epithelial cells. These effects in epithelial cells are ameliorated by either increasing fibroblast Tiam1 or decreasing fibroblast osteopontin. Finally, in seeded cell migration assays we find that either senescent or Tiam1-deficient fibroblasts induce increased epithelial cell migration that is dependent on fibroblast secretion of osteopontin. These findings indicate that one mechanism by which senescent fibroblasts promote neoplastic progression in associated tumors is through degradation of fibroblast Tiam1 protein and the consequent increase in secretion of osteopontin by fibroblasts.
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Affiliation(s)
- Jiewei Liu
- Molecular Oncology Research Institute, Tufts Medical Center Boston, MA 02111, USA
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45
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Ligeti E, Welti S, Scheffzek K. Inhibition and Termination of Physiological Responses by GTPase Activating Proteins. Physiol Rev 2012; 92:237-72. [DOI: 10.1152/physrev.00045.2010] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Physiological processes are strictly organized in space and time. However, in cell physiology research, more attention is given to the question of space rather than to time. To function as a signal, environmental changes must be restricted in time; they need not only be initiated but also terminated. In this review, we concentrate on the role of one specific protein family involved in biological signal termination. GTPase activating proteins (GAPs) accelerate the endogenously low GTP hydrolysis rate of monomeric guanine nucleotide-binding proteins (GNBPs), limiting thereby their prevalence in the active, GTP-bound form. We discuss cases where defective or excessive GAP activity of specific proteins causes significant alteration in the function of the nervous, endocrine, and hemopoietic systems, or contributes to development of infections and tumors. Biochemical and genetic data as well as observations from human pathology support the notion that GAPs represent vital elements in the spatiotemporal fine tuning of physiological processes.
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Affiliation(s)
- Erzsébet Ligeti
- Department of Physiology, Semmelweis University, Budapest, Hungary; Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany; and Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Stefan Welti
- Department of Physiology, Semmelweis University, Budapest, Hungary; Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany; and Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Klaus Scheffzek
- Department of Physiology, Semmelweis University, Budapest, Hungary; Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany; and Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
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46
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Abstract
Ras-GRF1 (GRF1) and Ras-GRF2 (GRF2) constitute a family of guanine nucleotide exchange factors (GEFs). The main isoforms, p140-GRF1 and p135-GRF2, have 2 GEF domains that give them the capacity to activate both Ras and Rac GTPases in response to signals from a variety of neurotransmitter receptors. GRF1 and GRF2 proteins are found predominantly in adult neurons of the central nervous system, although they can also be detected in a limited number of other tissues. p140-GRF1 and p135-GRF2 contain calcium/calmodulin-binding IQ domains that allow them to act as calcium sensors to mediate the actions of NMDA-type and calcium-permeable AMPA-type glutamate receptors. p140-GRF1 also mediates the action of dopamine receptors that signal through cAMP. Although p140-GRF1 and p135-GRF2 have similar functional domains, studies of GRF knockout mice show that they can play strikingly different roles in regulating MAP kinase family members, neuronal synaptic plasticity, specific forms of learning and memory, and behavioral responses to psychoactive drugs. In addition, the function of GRF proteins may vary in different regions of the brain. Alternative splice variants yielding smaller GRF1 gene isoforms with fewer functional domains also exist; however, their distinct roles in neurons have not been revealed. Continuing studies of these proteins should yield important insights into the biochemical basis of brain function as well as novel concepts to explain how complex signal transduction proteins, like Ras-GRFs, integrate multiple upstream signals into specific downstream outputs to control brain function.
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Affiliation(s)
- Larry A Feig
- Departments of Biochemistry and Neuroscience, Tufts University School of Medicine, Boston, MA, USA
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47
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Zhao H, Pykäläinen A, Lappalainen P. I-BAR domain proteins: linking actin and plasma membrane dynamics. Curr Opin Cell Biol 2010; 23:14-21. [PMID: 21093245 DOI: 10.1016/j.ceb.2010.10.005] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 10/11/2010] [Accepted: 10/17/2010] [Indexed: 02/05/2023]
Abstract
Dynamic plasma membrane rearrangements occur during many cellular processes including endocytosis, morphogenesis, and migration. Actin polymerization together with proteins that directly deform membranes, such as the BAR superfamily proteins, is essential for generation of membrane invaginations during endocytosis. Importantly, recent studies revealed that direct membrane deformation contributes also to the formation of plasma membrane protrusions such as filopodia and lamellipodia. Inverse BAR (I-BAR) domain proteins bind phosphoinositide-rich membrane with high affinity and generate negative membrane curvature to induce plasma membrane protrusions. I-BAR domain proteins, such as IRSp53, MIM, ABBA, and IRTKS also harbor many protein-protein interaction modules that link them to actin dynamics. Thus, I-BAR domain proteins may connect direct membrane deformation to actin polymerization in cell morphogenesis and migration.
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Affiliation(s)
- Hongxia Zhao
- Institute of Biotechnology, University of Helsinki, P.O. Box 56 (Viikinkaari 9), 00014 Helsinki, Finland
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48
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Abstract
Rho-family GTPases are molecular switches that transmit extracellular cues to intracellular signaling pathways. Their regulation is likely to be highly regulated in space and in time, but most of what is known about Rho-family GTPase signaling has been derived from techniques that do not resolve these dimensions. New imaging technologies now allow the visualization of Rho GTPase signaling with high spatio-temporal resolution. This has led to insights that significantly extend classic models and call for a novel conceptual framework. These approaches clearly show three things. First, Rho GTPase signaling dynamics occur on micrometer length scales and subminute timescales. Second, multiple subcellular pools of one given Rho GTPase can operate simultaneously in time and space to regulate a wide variety of morphogenetic events (e.g. leading-edge membrane protrusion, tail retraction, membrane ruffling). These different Rho GTPase subcellular pools might be described as 'spatio-temporal signaling modules' and might involve the specific interaction of one GTPase with different guanine nucleotide exchange factors (GEFs), GTPase-activating proteins (GAPs) and effectors. Third, complex spatio-temporal signaling programs that involve precise crosstalk between multiple Rho GTPase signaling modules regulate specific morphogenetic events. The next challenge is to decipher the molecular circuitry underlying this complex spatio-temporal modularity to produce integrated models of Rho GTPase signaling.
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Affiliation(s)
- Olivier Pertz
- Institute for Biochemistry and Genetics, Department of Biomedicine, University of Basel, Mattenstrasse 28, 4058 Basel, Switzerland.
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49
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Xu K, Rajagopal S, Klebba I, Dong S, Ji Y, Liu J, Kuperwasser C, Garlick JA, Naber SP, Buchsbaum RJ. The role of fibroblast Tiam1 in tumor cell invasion and metastasis. Oncogene 2010; 29:6533-42. [PMID: 20802514 PMCID: PMC2997941 DOI: 10.1038/onc.2010.385] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The co-evolution of tumors and their microenvironment involves bidirectional communication between tumor cells and tumor-associated stroma. Various cell types are present in tumor-associated stroma, of which fibroblasts are the most abundant. The Rac exchange factor Tiam1 is implicated in multiple signaling pathways in epithelial tumor cells and lack of Tiam1 in tumor cells retards tumor growth in Tiam1 knock-out mouse models. Conversely, tumors arising in Tiam1 knock-out mice have increased invasiveness. We have investigated the role of Tiam1 in tumor-associated fibroblasts as a modulator of tumor cell invasion and metastasis, using retroviral delivery of short hairpin RNA to suppress Tiam1 levels in three different experimental models. In spheroid co-culture of mammary epithelial cells and fibroblasts, Tiam1 silencing in fibroblasts led to increased epithelial cell outgrowth into matrix. In tissue-engineered human skin, Tiam1 silencing in dermal fibroblasts led to increased invasiveness of epidermal keratinocytes with premalignant features. In a model of human breast cancer in mice, co-implantation of mammary fibroblasts inhibited tumor invasion and metastasis, which was reversed by Tiam1 silencing in co-injected fibroblasts. These results suggest that stromal Tiam1 may play a role in modulating the effects of the tumor microenvironment on malignant cell invasion and metastasis. This suggests a set of pathways for further investigation, with implications for future therapeutic targets.
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Affiliation(s)
- K Xu
- Molecular Oncology Research Institute, Tufts Medical Center, Tufts University, Boston, MA 02111, USA
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50
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Harmon B, Campbell N, Ratner L. Role of Abl kinase and the Wave2 signaling complex in HIV-1 entry at a post-hemifusion step. PLoS Pathog 2010; 6:e1000956. [PMID: 20585556 PMCID: PMC2887473 DOI: 10.1371/journal.ppat.1000956] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Accepted: 05/19/2010] [Indexed: 11/18/2022] Open
Abstract
Entry of human immunodeficiency virus type 1 (HIV-1) commences with binding of the envelope glycoprotein (Env) to the receptor CD4, and one of two coreceptors, CXCR4 or CCR5. Env-mediated signaling through coreceptor results in Galphaq-mediated Rac activation and actin cytoskeleton rearrangements necessary for fusion. Guanine nucleotide exchange factors (GEFs) activate Rac and regulate its downstream protein effectors. In this study we show that Env-induced Rac activation is mediated by the Rac GEF Tiam-1, which associates with the adaptor protein IRSp53 to link Rac to the Wave2 complex. Rac and the tyrosine kinase Abl then activate the Wave2 complex and promote Arp2/3-dependent actin polymerization. Env-mediated cell-cell fusion, virus-cell fusion and HIV-1 infection are dependent on Tiam-1, Abl, IRSp53, Wave2, and Arp3 as shown by attenuation of fusion and infection in cells expressing siRNA targeted to these signaling components. HIV-1 Env-dependent cell-cell fusion, virus-cell fusion and infection were also inhibited by Abl kinase inhibitors, imatinib, nilotinib, and dasatinib. Treatment of cells with Abl kinase inhibitors did not affect cell viability or surface expression of CD4 and CCR5. Similar results with inhibitors and siRNAs were obtained when Env-dependent cell-cell fusion, virus-cell fusion or infection was measured, and when cell lines or primary cells were the target. Using membrane curving agents and fluorescence microscopy, we showed that inhibition of Abl kinase activity arrests fusion at the hemifusion (lipid mixing) step, suggesting a role for Abl-mediated actin remodeling in pore formation and expansion. These results suggest a potential utility of Abl kinase inhibitors to treat HIV-1 infected patients.
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Affiliation(s)
- Brooke Harmon
- Division of Molecular Oncology, Washington University School of Medicine, St Louis, Missouri, United States of America
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