1
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Kitzinger R, Fritz G, Henninger C. Nuclear RAC1 is a modulator of the doxorubicin-induced DNA damage response. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119320. [PMID: 35817175 DOI: 10.1016/j.bbamcr.2022.119320] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 06/17/2022] [Accepted: 06/22/2022] [Indexed: 06/15/2023]
Abstract
Rho GTPases like RAC1 are localized on the inner side of the outer cell membrane where they act as molecular switches that can trigger signal transduction pathways in response to various extracellular stimuli. Nuclear functions of RAC1 were identified that are related to mitosis, cell cycle arrest and apoptosis. Previously, we showed that RAC1 plays a role in the doxorubicin (Dox)-induced DNA damage response (DDR). In this context it is still unknown whether cytosolic RAC1 modulates the Dox-induced DDR or if a nuclear fraction of RAC1 is involved. Here, we silenced RAC1 in mouse embryonic fibroblasts (MEF) pharmacologically with EHT1864 or by using siRNA against Rac1. Additionally, we transfected MEF with RAC1 mutants (wild-type, dominant-negative, constitutively active) containing a nuclear localization sequence (NLS). Afterwards, we analysed the Dox-induced DDR by evaluation of fluorescent nuclear γH2AX and 53BP1 foci formation, as well as by detection of activated proteins of the DDR by western blot to elucidate the role of nuclear RAC1 in the DDR. Treatment with EHT1864 as well as Rac1 knock-down reduced the Dox-induced DSB-formation to a similar extent. Enhanced nuclear localization of dominant-negative as well as constitutively active RAC1 mimicked these effects. Expression of the RAC1 mutants altered the Dox-induced amount of pP53 and pKAP1 protein. The observed effects were independent of S1981 ATM phosphorylation. We conclude that RAC1 is required for a substantial activation of the Dox-induced DDR and balanced levels of active/inactive RAC1 inside the nucleus are a prerequisite for this response.
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Affiliation(s)
- Rebekka Kitzinger
- Institute of Toxicology, Medical Faculty of the Heinrich Heine University Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany
| | - Gerhard Fritz
- Institute of Toxicology, Medical Faculty of the Heinrich Heine University Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany
| | - Christian Henninger
- Institute of Toxicology, Medical Faculty of the Heinrich Heine University Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany.
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2
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Lan T, Yu M, Chen W, Yin J, Chang HT, Tang S, Zhao Y, Svoronos S, Wong SWK, Tseng Y. Decomposition of cell activities revealing the role of the cell cycle in driving biofunctional heterogeneity. Sci Rep 2021; 11:23431. [PMID: 34873244 PMCID: PMC8648726 DOI: 10.1038/s41598-021-02926-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 11/16/2021] [Indexed: 11/09/2022] Open
Abstract
Heterogeneity of cell phenotypes remains a barrier in progressing cell research and a challenge in conquering cancer-related drug resistance. Cell morphology, the most direct property of cell phenotype, evolves along the progression of the cell cycle; meanwhile, cell motility, the dynamic property of cell phenotype, also alters over the cell cycle. However, a quantifiable research understanding the relationship between the cell cycle and cell migration is missing. Herein, we coordinate the migratory behaviours of NIH 3T3 fibroblasts to their corresponding phases of the cell cycle, the G1, the S, and the G2 phases, and explain the relationship through the spatiotemporal arrangements between the Rho GTPases’ signals and cyclin-dependent kinase inhibitors, p21Cip1, and p27Kip1. Taken together, we demonstrate that both cell morphology and the dynamic subcellular behaviour are homogenous within each stage of the cell cycle phases but heterogenous between phases through quantitative cell analyses and an interactive molecular mechanism between the cell cycle and cell migration, posing potential implications in countering drug resistance.
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Affiliation(s)
- Tian Lan
- Innovation Research Institute of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, 250355, Shandong, China.,Department of Chemical Engineering, University of Florida, Gainesville, FL, 32611, USA
| | - Meng Yu
- Innovation Research Institute of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, 250355, Shandong, China
| | - Weisheng Chen
- Department of Chemical Engineering, University of Florida, Gainesville, FL, 32611, USA
| | - Jun Yin
- Department of Chemical Engineering, University of Florida, Gainesville, FL, 32611, USA
| | - Hsiang-Tsun Chang
- Department of Chemical Engineering, University of Florida, Gainesville, FL, 32611, USA
| | - Shan Tang
- Department of Chemical Engineering, University of Florida, Gainesville, FL, 32611, USA
| | - Ye Zhao
- Innovation Research Institute of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, 250355, Shandong, China
| | - Spyros Svoronos
- Department of Chemical Engineering, University of Florida, Gainesville, FL, 32611, USA
| | - Samuel W K Wong
- Department of Statistics and Actuarial Science, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
| | - Yiider Tseng
- Innovation Research Institute of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Jinan, 250355, Shandong, China. .,Department of Chemical Engineering, University of Florida, Gainesville, FL, 32611, USA.
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3
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EphA2 signaling within integrin adhesions regulates fibrillar adhesion elongation and fibronectin deposition. Matrix Biol 2021; 103-104:1-21. [PMID: 34537369 DOI: 10.1016/j.matbio.2021.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 09/01/2021] [Accepted: 09/09/2021] [Indexed: 12/28/2022]
Abstract
The multifunctional glycoprotein fibronectin influences several crucial cellular processes and contributes to multiple pathologies. While a link exists between fibronectin-associated pathologies and the receptor tyrosine kinase EphA2, the mechanism by which EphA2 promotes fibronectin matrix remodeling remains unknown. We previously demonstrated that EphA2 deletion reduces smooth muscle fibronectin deposition and blunts fibronectin deposition in atherosclerosis without influencing fibronectin expression. We now show that EphA2 expression is required for contractility-dependent elongation of tensin- and α5β1 integrin-rich fibrillar adhesions that drive fibronectin fibrillogenesis. Mechanistically, EphA2 localizes to integrin adhesions where focal adhesion kinase mediates ligand-independent Y772 phosphorylation, and mutation of this site significantly blunts fibrillar adhesion length. EphA2 deficiency decreases smooth muscle cell contractility by enhancing p190RhoGAP activation and reducing RhoA activity, whereas stimulating RhoA signaling in EphA2 deficient cells rescues fibrillar adhesion elongation. Together, these data identify EphA2 as a novel regulator of fibrillar adhesion elongation and provide the first data identifying a role for EphA2 signaling in integrin adhesions.
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4
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Bolado-Carrancio A, Rukhlenko OS, Nikonova E, Tsyganov MA, Wheeler A, Garcia-Munoz A, Kolch W, von Kriegsheim A, Kholodenko BN. Periodic propagating waves coordinate RhoGTPase network dynamics at the leading and trailing edges during cell migration. eLife 2020; 9:58165. [PMID: 32705984 PMCID: PMC7380942 DOI: 10.7554/elife.58165] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 07/02/2020] [Indexed: 12/27/2022] Open
Abstract
Migrating cells need to coordinate distinct leading and trailing edge dynamics but the underlying mechanisms are unclear. Here, we combine experiments and mathematical modeling to elaborate the minimal autonomous biochemical machinery necessary and sufficient for this dynamic coordination and cell movement. RhoA activates Rac1 via DIA and inhibits Rac1 via ROCK, while Rac1 inhibits RhoA through PAK. Our data suggest that in motile, polarized cells, RhoA–ROCK interactions prevail at the rear, whereas RhoA-DIA interactions dominate at the front where Rac1/Rho oscillations drive protrusions and retractions. At the rear, high RhoA and low Rac1 activities are maintained until a wave of oscillatory GTPase activities from the cell front reaches the rear, inducing transient GTPase oscillations and RhoA activity spikes. After the rear retracts, the initial GTPase pattern resumes. Our findings show how periodic, propagating GTPase waves coordinate distinct GTPase patterns at the leading and trailing edge dynamics in moving cells.
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Affiliation(s)
- Alfonso Bolado-Carrancio
- Edinburgh Cancer Research Centre, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Oleksii S Rukhlenko
- Systems Biology Ireland, School of Medicine and Medical Science, University College Dublin, Belfield, Ireland
| | - Elena Nikonova
- Systems Biology Ireland, School of Medicine and Medical Science, University College Dublin, Belfield, Ireland
| | - Mikhail A Tsyganov
- Systems Biology Ireland, School of Medicine and Medical Science, University College Dublin, Belfield, Ireland.,Institute of Theoretical and Experimental Biophysics, Pushchino, Russian Federation
| | - Anne Wheeler
- Edinburgh Cancer Research Centre, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Amaya Garcia-Munoz
- Systems Biology Ireland, School of Medicine and Medical Science, University College Dublin, Belfield, Ireland
| | - Walter Kolch
- Systems Biology Ireland, School of Medicine and Medical Science, University College Dublin, Belfield, Ireland.,Conway Institute of Biomolecular & Biomedical Research, University College Dublin, Belfield, Ireland
| | - Alex von Kriegsheim
- Edinburgh Cancer Research Centre, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom.,Systems Biology Ireland, School of Medicine and Medical Science, University College Dublin, Belfield, Ireland
| | - Boris N Kholodenko
- Systems Biology Ireland, School of Medicine and Medical Science, University College Dublin, Belfield, Ireland.,Conway Institute of Biomolecular & Biomedical Research, University College Dublin, Belfield, Ireland.,Department of Pharmacology, Yale University School of Medicine, New Haven, United States
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5
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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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6
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Feddersen CR, Schillo JL, Varzavand A, Vaughn HR, Wadsworth LS, Voigt AP, Zhu EY, Jennings BM, Mullen SA, Bobera J, Riordan JD, Stipp CS, Dupuy AJ. Src-Dependent DBL Family Members Drive Resistance to Vemurafenib in Human Melanoma. Cancer Res 2019; 79:5074-5087. [PMID: 31416844 PMCID: PMC6774858 DOI: 10.1158/0008-5472.can-19-0244] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 06/05/2019] [Accepted: 08/06/2019] [Indexed: 12/25/2022]
Abstract
The use of selective BRAF inhibitors (BRAFi) has produced remarkable outcomes for patients with advanced cutaneous melanoma harboring a BRAFV600E mutation. Unfortunately, the majority of patients eventually develop drug-resistant disease. We employed a genetic screening approach to identify gain-of-function mechanisms of BRAFi resistance in two independent melanoma cell lines. Our screens identified both known and unappreciated drivers of BRAFi resistance, including multiple members of the DBL family. Mechanistic studies identified a DBL/RAC1/PAK signaling axis capable of driving resistance to both current and next-generation BRAFis. However, we show that the SRC inhibitor, saracatinib, can block the DBL-driven resistance. Our work highlights the utility of our straightforward genetic screening method in identifying new drug combinations to combat acquired BRAFi resistance. SIGNIFICANCE: A simple, rapid, and flexible genetic screening approach identifies genes that drive resistance to MAPK inhibitors when overexpressed in human melanoma cells.
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Affiliation(s)
- Charlotte R Feddersen
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Jacob L Schillo
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Afshin Varzavand
- Department of Biology, College of Liberal Arts and Sciences, University of Iowa, Iowa City, Iowa
| | - Hayley R Vaughn
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Lexy S Wadsworth
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Andrew P Voigt
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Eliot Y Zhu
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Brooke M Jennings
- Department of Biology, College of Liberal Arts and Sciences, University of Iowa, Iowa City, Iowa
| | - Sarah A Mullen
- Department of Biology, College of Liberal Arts and Sciences, University of Iowa, Iowa City, Iowa
| | - Jeremy Bobera
- Department of Biology, College of Liberal Arts and Sciences, University of Iowa, Iowa City, Iowa
| | - Jesse D Riordan
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Christopher S Stipp
- Department of Biology, College of Liberal Arts and Sciences, University of Iowa, Iowa City, Iowa.
- Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa
| | - Adam J Dupuy
- Department of Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, Iowa.
- Holden Comprehensive Cancer Center, University of Iowa, Iowa City, Iowa
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7
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Selection and Characterization of a Nanobody Biosensor of GTP-Bound RHO Activities. Antibodies (Basel) 2019; 8:antib8010008. [PMID: 31544814 PMCID: PMC6640709 DOI: 10.3390/antib8010008] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 12/19/2018] [Accepted: 12/20/2018] [Indexed: 12/28/2022] Open
Abstract
RHO (Ras HOmologous) GTPases are molecular switches that activate, in their state bound to Guanosine triphosphate (GTP), key signaling pathways, which involve actin cytoskeleton dynamics. Previously, we selected the nanobody RH12, from a synthetic phage display library, which binds the GTP-bound active conformation of RHOA (Ras Homologous family member A). However, when expressed as an intracellular antibody, its blocking effect on RHO signaling led to a loss of actin fibers, which in turn affected cell shape and cell survival. Here, in order to engineer an intracellular biosensor of RHOA-GTP activation, we screened the same phage nanobody library and identified another RHO-GTP selective intracellular nanobody, but with no apparent toxicity. The recombinant RH57 nanobody displays high affinity towards GTP-bound RHOA/B/C subgroup of small GTPases in vitro. Intracellular expression of the RH57 allowed selective co-precipitation with the GTP-bound state of the endogenous RHOA subfamily. When expressed as a fluorescent fusion protein, the chromobody GFP-RH57 was localized to the inner plasma membrane upon stimulation of the activation of endogenous RHO. Finally, the RH57 nanobody was used to establish a BRET-based biosensor (Bioluminescence Resonance Energy Transfer) of RHO activation. The dynamic range of the BRET signal could potentially offer new opportunities to develop cell-based screening of RHOA subfamily activation modulators.
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8
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Liu W, Zhou Y, Peng T, Zhou P, Ding X, Li Z, Zhong H, Xu Y, Chen S, Hang HC, Shao F. N ε-fatty acylation of multiple membrane-associated proteins by Shigella IcsB effector to modulate host function. Nat Microbiol 2018; 3:996-1009. [PMID: 30061757 PMCID: PMC6466622 DOI: 10.1038/s41564-018-0215-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 06/27/2018] [Indexed: 11/09/2022]
Abstract
Shigella flexneri, an intracellular Gram-negative bacterium causative for shigellosis, employs a type III secretion system to deliver virulence effectors into host cells. One such effector, IcsB, is critical for S. flexneri intracellular survival and pathogenesis, but its mechanism of action is unknown. Here, we discover that IcsB is an 18-carbon fatty acyltransferase catalysing lysine Nε-fatty acylation. IcsB disrupted the actin cytoskeleton in eukaryotes, resulting from Nε-fatty acylation of RhoGTPases on lysine residues in their polybasic region. Chemical proteomic profiling identified about 60 additional targets modified by IcsB during infection, which were validated by biochemical assays. Most IcsB targets are membrane-associated proteins bearing a lysine-rich polybasic region, including members of the Ras, Rho and Rab families of small GTPases. IcsB also modifies SNARE proteins and other non-GTPase substrates, suggesting an extensive interplay between S. flexneri and host membrane trafficking. IcsB is localized on the Shigella-containing vacuole to fatty-acylate its targets. Knockout of CHMP5-one of the IcsB targets and a component of the ESCRT-III complex-specifically affected S. flexneri escape from host autophagy. The unique Nε-fatty acyltransferase activity of IcsB and its altering of the fatty acylation landscape of host membrane proteomes represent an unprecedented mechanism in bacterial pathogenesis.
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Affiliation(s)
- Wang Liu
- College of Life Science, Peking University, Beijing, China
- Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, National Institute of Biological Sciences, Beijing, China
- National Institute of Biological Sciences, Beijing, China
| | - Yan Zhou
- National Institute of Biological Sciences, Beijing, China
- College of Life Sciences, Beijing Normal University, Beijing, China
- Life Sciences Institute and Innovation Center for Cell Signaling Network, Zhejiang University, Hangzhou, Zhejiang, China
| | - Tao Peng
- School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen, China
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY, USA
| | - Ping Zhou
- National Institute of Biological Sciences, Beijing, China
| | - Xiaojun Ding
- National Institute of Biological Sciences, Beijing, China
| | - Zilin Li
- National Institute of Biological Sciences, Beijing, China
| | - Haoyu Zhong
- National Institute of Biological Sciences, Beijing, China
| | - Yue Xu
- National Institute of Biological Sciences, Beijing, China
| | - She Chen
- National Institute of Biological Sciences, Beijing, China
| | - Howard C Hang
- Laboratory of Chemical Biology and Microbial Pathogenesis, The Rockefeller University, New York, NY, USA.
| | - Feng Shao
- National Institute of Biological Sciences, Beijing, China.
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China.
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9
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Ito S, Okuda S, Abe M, Fujimoto M, Onuki T, Nishimura T, Takeichi M. Induced cortical tension restores functional junctions in adhesion-defective carcinoma cells. Nat Commun 2017; 8:1834. [PMID: 29184140 PMCID: PMC5705652 DOI: 10.1038/s41467-017-01945-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 10/27/2017] [Indexed: 11/08/2022] Open
Abstract
Normal epithelial cells are stably connected to each other via the apical junctional complex (AJC). AJCs, however, tend to be disrupted during tumor progression, and this process is implicated in cancer dissemination. Here, using colon carcinoma cells that fail to form AJCs, we investigated molecular defects behind this failure through a search for chemical compounds that could restore AJCs, and found that microtubule-polymerization inhibitors (MTIs) were effective. MTIs activated GEF-H1/RhoA signaling, causing actomyosin contraction at the apical cortex. This contraction transmitted force to the cadherin-catenin complex, resulting in a mechanosensitive recruitment of vinculin to cell junctions. This process, in turn, recruited PDZ-RhoGEF to the junctions, leading to the RhoA/ROCK/LIM kinase/cofilin-dependent stabilization of the junctions. RhoGAP depletion mimicked these MTI-mediated processes. Cells that normally organize AJCs did not show such MTI/RhoA sensitivity. Thus, advanced carcinoma cells require elevated RhoA activity for establishing robust junctions, which triggers tension-sensitive reorganization of actin/adhesion regulators.
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Affiliation(s)
- Shoko Ito
- Laboratory for Cell Adhesion and Tissue Patterning, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-Minamimachi, Chuo-ku, Kobe, 650-0047, Japan
| | - Satoru Okuda
- Laboratoty for In Vitro Histogenesis, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-Minamimachi, Chuo-ku, Kobe, 650-0047, Japan
| | - Masako Abe
- Seed Compounds Exploratory Unit for Drug Discovery Platform, Drug Discovery Platforms Cooperation Division, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, 351-0198, Japan
| | - Mari Fujimoto
- Seed Compounds Exploratory Unit for Drug Discovery Platform, Drug Discovery Platforms Cooperation Division, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, 351-0198, Japan
| | - Tetsuo Onuki
- Seed Compounds Exploratory Unit for Drug Discovery Platform, Drug Discovery Platforms Cooperation Division, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, 351-0198, Japan
| | - Tamako Nishimura
- Laboratory for Cell Adhesion and Tissue Patterning, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-Minamimachi, Chuo-ku, Kobe, 650-0047, Japan
- Nara Institute of Science and Technology, Ikoma, 630-0192, Japan
| | - Masatoshi Takeichi
- Laboratory for Cell Adhesion and Tissue Patterning, RIKEN Center for Developmental Biology, 2-2-3 Minatojima-Minamimachi, Chuo-ku, Kobe, 650-0047, Japan.
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10
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Xavier-Ferrucio J, Ricon L, Vieira K, Longhini AL, Lazarini M, Bigarella CL, Franchi G, Krause DS, Saad STO. Hematopoietic defects in response to reduced Arhgap21. Stem Cell Res 2017; 26:17-27. [PMID: 29212046 PMCID: PMC6084430 DOI: 10.1016/j.scr.2017.11.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 11/13/2017] [Accepted: 11/20/2017] [Indexed: 12/28/2022] Open
Abstract
Arhgap21 is a member of the Rho GTPase activating protein (RhoGAP) family, which function as negative regulators of Rho GTPases. Arhgap21 has been implicated in adhesion and migration of cancer cells. However, the role of Arhgap21 has never been investigated in hematopoietic cells. Herein, we evaluated functional aspects of hematopoietic stem and progenitor cells (HSPC) using a haploinsufficient (Arhgap21+/-) mouse. Our results show that Arhgap21+/- mice have an increased frequency of phenotypic HSC, impaired ability to form progenitor colonies in vitro and decreased hematopoietic engraftment in vivo, along with a decrease in LSK cell frequency during serial bone marrow transplantation. Arhgap21+/- hematopoietic progenitor cells have impaired adhesion and enhanced mobilization of immature LSK and myeloid progenitors. Arhgap21+/- mice also exhibit reduced erythroid commitment and differentiation, which was recapitulated in human primary cells, in which knockdown of ARHGAP21 in CMP and MEP resulted in decreased erythroid commitment. Finally, we observed enhanced RhoC activity in the bone marrow cells of Arhgap21+/- mice, indicating that Arhgap21 functions in hematopoiesis may be at least partially mediated by RhoC inactivation.
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Affiliation(s)
- Juliana Xavier-Ferrucio
- Hematology and Blood Transfusion Center University of Campinas/Hemocentro-UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, SP, Brazil; Department of Laboratory Medicine, Yale School of Medicine, New Haven, CT, USA.; Yale Stem Cell Center, Yale School of Medicine, New Haven, CT, USA
| | - Lauremília Ricon
- Hematology and Blood Transfusion Center University of Campinas/Hemocentro-UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, SP, Brazil
| | - Karla Vieira
- Hematology and Blood Transfusion Center University of Campinas/Hemocentro-UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, SP, Brazil
| | - Ana Leda Longhini
- Hematology and Blood Transfusion Center University of Campinas/Hemocentro-UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, SP, Brazil
| | - Mariana Lazarini
- Hematology and Blood Transfusion Center University of Campinas/Hemocentro-UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, SP, Brazil; Department of Biological Sciences, Federal University of São Paulo, Diadema, Brazil
| | - Carolina Louzão Bigarella
- Hematology and Blood Transfusion Center University of Campinas/Hemocentro-UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, SP, Brazil
| | - Gilberto Franchi
- Onco-Hematological Child Research Center (CIPOI), Faculty of Medical Sciences, University of Campinas-UNICAMP, Campinas, SP, Brazil
| | - Diane S Krause
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, CT, USA.; Yale Stem Cell Center, Yale School of Medicine, New Haven, CT, USA
| | - Sara T O Saad
- Hematology and Blood Transfusion Center University of Campinas/Hemocentro-UNICAMP, Instituto Nacional de Ciência e Tecnologia do Sangue, Campinas, SP, Brazil.
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11
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Karabiyik C, Fernandes R, Figueiredo FR, Socodato R, Brakebusch C, Lambertsen KL, Relvas JB, Santos SD. Neuronal Rho GTPase Rac1 elimination confers neuroprotection in a mouse model of permanent ischemic stroke. Brain Pathol 2017; 28:569-580. [PMID: 28960571 DOI: 10.1111/bpa.12562] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 09/21/2017] [Indexed: 01/08/2023] Open
Abstract
The Rho GTPase Rac1 is a multifunctional protein involved in distinct pathways ranging from development to pathology. The aim of the present study was to unravel the contribution of neuronal Rac1 in regulating the response to brain injury induced by permanent focal cerebral ischemia (pMCAO). Our results show that pMCAO significantly increased total Rac1 levels in wild type mice, mainly through rising nuclear Rac1, while a reduction in Rac1 activation was observed. Such changes preceded cell death induced by excitotoxic stress. Pharmacological inhibition of Rac1 in primary neuronal cortical cells prevented the increase in oxidative stress induced after overactivation of glutamate receptors. However, this was not sufficient to prevent the associated neuronal cell death. In contrast, RNAi-mediated knock down of Rac1 in primary cortical neurons prevented cell death elicited by glutamate excitotoxicity and decreased the activity of NADPH oxidase. To test whether in vivo down regulation of neuronal Rac1 was neuroprotective after pMCAO, we used tamoxifen-inducible neuron-specific conditional Rac1-knockout mice. We observed a significant 50% decrease in brain infarct volume of knockout mice and a concomitant increase in HIF-1α expression compared to littermate control mice, demonstrating that ablation of Rac1 in neurons is neuroprotective. Transmission electron microscopy performed in the ischemic brain showed that lysosomes in the infarct of Rac1- knockout mice were preserved at similar levels to those of non-infarcted tissue, while littermate mice displayed a decrease in the number of lysosomes, further corroborating the notion that Rac1 ablation in neurons is neuroprotective. Our results demonstrate that Rac1 plays important roles in the ischemic pathological cascade and that modulation of its levels is of therapeutic interest.
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Affiliation(s)
- Cansu Karabiyik
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Glial Cell Biology, IBMC- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense C, Denmark
| | - Rui Fernandes
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,HEMS, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Francisco Rosário Figueiredo
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,HEMS, IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Renato Socodato
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Glial Cell Biology, IBMC- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Cord Brakebusch
- Biotech Research and Innovation Center, University of Copenhagen, Denmark
| | - Kate Lykke Lambertsen
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense C, Denmark.,Department of Neurology, Odense University Hospital, Odence C, Denmark.,BRIDGE - Brain Research - Inter-Disciplinary Guided Excellence, Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - João Bettencourt Relvas
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Glial Cell Biology, IBMC- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Sofia Duque Santos
- i3S - Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Glial Cell Biology, IBMC- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,INEB - Instituto de Engenharia Biomédica, Universidade do Porto, Porto, Portugal
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12
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Wald JH, Hatakeyama J, Printsev I, Cuevas A, Fry WH, Saldana MJ, Vorst KV, Rowson-Hodel A, Angelastro JM, Sweeney C, Carraway KL. Suppression of planar cell polarity signaling and migration in glioblastoma by Nrdp1-mediated Dvl polyubiquitination. Oncogene 2017; 36:5158-5167. [PMID: 28481871 PMCID: PMC5589482 DOI: 10.1038/onc.2017.126] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 02/15/2017] [Accepted: 03/23/2017] [Indexed: 12/16/2022]
Abstract
The lethality of the aggressive brain tumor glioblastoma multiforme (GBM) results in part from its strong propensity to invade surrounding normal brain tissue. Although oncogenic drivers such as epidermal growth factor receptor activation and Phosphatase and Tensin homolog inactivation are thought to promote the motility and invasiveness of GBM cells via phosphatidylinostitol 3-kinase activation, other unexplored mechanisms may also contribute to malignancy. Here we demonstrate that several components of the planar cell polarity (PCP) arm of non-canonical Wnt signaling including VANGL1, VANGL2 and FZD7 are transcriptionally upregulated in glioma and correlate with poorer patient outcome. Knockdown of the core PCP pathway component VANGL1 suppresses the motility of GBM cell lines, pointing to an important mechanistic role for this pathway in glioblastoma malignancy. We further observe that restoration of Nrdp1, a RING finger type E3 ubiquitin ligase whose suppression in GBM also correlates with poor prognosis, reduces GBM cell migration and invasiveness by suppressing PCP signaling. Our observations indicate that Nrdp1 physically interacts with the Vangl1 and Vangl2 proteins to mediate the K63-linked polyubiquitination of the Dishevelled, Egl-10 and Pleckstrin (DEP) domain of the Wnt pathway protein Dishevelled (Dvl). Ubiquitination hinders Dvl binding to phosphatidic acid, an interaction necessary for efficient Dvl recruitment to the plasma membrane upon Wnt stimulation of Fzd receptor and for the propagation of downstream signals. We conclude that the PCP pathway contributes significantly to the motility and hence the invasiveness of GBM cells, and that Nrdp1 acts as a negative regulator of PCP signaling by inhibiting Dvl through a novel polyubiquitination mechanism. We propose that the upregulation of core PCP components, together with the loss of the key negative regulator Nrdp1, act coordinately to promote GBM invasiveness and malignancy.
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Affiliation(s)
- Jessica H. Wald
- Department of Biochemistry and Molecular Medicine, and UC Davis Comprehensive Cancer Center, University of California Davis School of Medicine, Sacramento, CA, USA
| | - Jason Hatakeyama
- Department of Biochemistry and Molecular Medicine, and UC Davis Comprehensive Cancer Center, University of California Davis School of Medicine, Sacramento, CA, USA
| | - Ignat Printsev
- Department of Biochemistry and Molecular Medicine, and UC Davis Comprehensive Cancer Center, University of California Davis School of Medicine, Sacramento, CA, USA
| | - Antonio Cuevas
- Department of Biochemistry and Molecular Medicine, and UC Davis Comprehensive Cancer Center, University of California Davis School of Medicine, Sacramento, CA, USA
| | - William H.D. Fry
- Department of Biochemistry and Molecular Medicine, and UC Davis Comprehensive Cancer Center, University of California Davis School of Medicine, Sacramento, CA, USA
| | - Matthew J. Saldana
- Department of Biochemistry and Molecular Medicine, and UC Davis Comprehensive Cancer Center, University of California Davis School of Medicine, Sacramento, CA, USA
| | - Kacey Vander Vorst
- Department of Biochemistry and Molecular Medicine, and UC Davis Comprehensive Cancer Center, University of California Davis School of Medicine, Sacramento, CA, USA
| | - Ashley Rowson-Hodel
- Department of Biochemistry and Molecular Medicine, and UC Davis Comprehensive Cancer Center, University of California Davis School of Medicine, Sacramento, CA, USA
| | - James M. Angelastro
- Department of Molecular Biosciences, University of California Davis School of Veterinary Medicine, Davis, CA, USA
| | - Colleen Sweeney
- Department of Biochemistry and Molecular Medicine, and UC Davis Comprehensive Cancer Center, University of California Davis School of Medicine, Sacramento, CA, USA
| | - Kermit L. Carraway
- Department of Biochemistry and Molecular Medicine, and UC Davis Comprehensive Cancer Center, University of California Davis School of Medicine, Sacramento, CA, USA
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13
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More SK, Chiplunkar SV, Kalraiya RD. Galectin-3-induced cell spreading and motility relies on distinct signaling mechanisms compared to fibronectin. Mol Cell Biochem 2016; 416:179-91. [DOI: 10.1007/s11010-016-2706-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 04/19/2016] [Indexed: 12/14/2022]
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14
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Amphetamine activates Rho GTPase signaling to mediate dopamine transporter internalization and acute behavioral effects of amphetamine. Proc Natl Acad Sci U S A 2015; 112:E7138-47. [PMID: 26553986 DOI: 10.1073/pnas.1511670112] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Acute amphetamine (AMPH) exposure elevates extracellular dopamine through a variety of mechanisms that include inhibition of dopamine reuptake, depletion of vesicular stores, and facilitation of dopamine efflux across the plasma membrane. Recent work has shown that the DAT substrate AMPH, unlike cocaine and other nontransported blockers, can also stimulate endocytosis of the plasma membrane dopamine transporter (DAT). Here, we show that when AMPH enters the cytoplasm it rapidly stimulates DAT internalization through a dynamin-dependent, clathrin-independent process. This effect, which can be observed in transfected cells, cultured dopamine neurons, and midbrain slices, is mediated by activation of the small GTPase RhoA. Inhibition of RhoA activity with C3 exotoxin or a dominant-negative RhoA blocks AMPH-induced DAT internalization. These actions depend on AMPH entry into the cell and are blocked by the DAT inhibitor cocaine. AMPH also stimulates cAMP accumulation and PKA-dependent inactivation of RhoA, thus providing a mechanism whereby PKA- and RhoA-dependent signaling pathways can interact to regulate the timing and robustness of AMPH's effects on DAT internalization. Consistent with this model, the activation of D1/D5 receptors that couple to PKA in dopamine neurons antagonizes RhoA activation, DAT internalization, and hyperlocomotion observed in mice after AMPH treatment. These observations support the existence of an unanticipated intracellular target that mediates the effects of AMPH on RhoA and cAMP signaling and suggest new pathways to target to disrupt AMPH action.
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15
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Hwang DY, Kohl S, Fan X, Vivante A, Chan S, Dworschak GC, Schulz J, van Eerde AM, Hilger AC, Gee HY, Pennimpede T, Herrmann BG, van de Hoek G, Renkema KY, Schell C, Huber TB, Reutter HM, Soliman NA, Stajic N, Bogdanovic R, Kehinde EO, Lifton RP, Tasic V, Lu W, Hildebrandt F. Mutations of the SLIT2-ROBO2 pathway genes SLIT2 and SRGAP1 confer risk for congenital anomalies of the kidney and urinary tract. Hum Genet 2015; 134:905-16. [PMID: 26026792 PMCID: PMC4497857 DOI: 10.1007/s00439-015-1570-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 05/18/2015] [Indexed: 12/26/2022]
Abstract
Congenital anomalies of the kidney and urinary tract (CAKUT) account for 40-50% of chronic kidney disease that manifests in the first two decades of life. Thus far, 31 monogenic causes of isolated CAKUT have been described, explaining ~12% of cases. To identify additional CAKUT-causing genes, we performed whole-exome sequencing followed by a genetic burden analysis in 26 genetically unsolved families with CAKUT. We identified two heterozygous mutations in SRGAP1 in 2 unrelated families. SRGAP1 is a small GTPase-activating protein in the SLIT2-ROBO2 signaling pathway, which is essential for development of the metanephric kidney. We then examined the pathway-derived candidate gene SLIT2 for mutations in cohort of 749 individuals with CAKUT and we identified 3 unrelated individuals with heterozygous mutations. The clinical phenotypes of individuals with mutations in SLIT2 or SRGAP1 were cystic dysplastic kidneys, unilateral renal agenesis, and duplicated collecting system. We show that SRGAP1 is expressed in early mouse nephrogenic mesenchyme and that it is coexpressed with ROBO2 in SIX2-positive nephron progenitor cells of the cap mesenchyme in developing rat kidney. We demonstrate that the newly identified mutations in SRGAP1 lead to an augmented inhibition of RAC1 in cultured human embryonic kidney cells and that the SLIT2 mutations compromise the ability of the SLIT2 ligand to inhibit cell migration. Thus, we report on two novel candidate genes for causing monogenic isolated CAKUT in humans.
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Affiliation(s)
- Daw-Yang Hwang
- Division of Nephrology, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Division of Nephrology, Department of Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Stefan Kohl
- Division of Nephrology, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Xueping Fan
- Renal Section, Department of Medicine, Boston University Medical Center, Boston, MA, USA
| | - Asaf Vivante
- Division of Nephrology, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Stefanie Chan
- Renal Section, Department of Medicine, Boston University Medical Center, Boston, MA, USA
| | - Gabriel C Dworschak
- Division of Nephrology, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Institute of Human Genetics, University of Bonn, Bonn, Germany
| | - Julian Schulz
- Division of Nephrology, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Albertien M van Eerde
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Alina C Hilger
- Institute of Human Genetics, University of Bonn, Bonn, Germany
| | - Heon Yung Gee
- Division of Nephrology, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Tracie Pennimpede
- Max Planck Institute for Molecular Genetics, Developmental Genetics Department, Berlin, Germany
| | - Bernhard G Herrmann
- Max Planck Institute for Molecular Genetics, Developmental Genetics Department, Berlin, Germany
| | - Glenn van de Hoek
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Kirsten Y Renkema
- Department of Medical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Christoph Schell
- Renal Division, University Hospital Freiburg, Freiburg, Germany
- Spemann Graduate School of Biology and Medicine, Albert-Ludwigs-University, Freiburg, Germany
- Faculty of Biology, Albert-Ludwigs-University, Freiburg, Germany
| | - Tobias B Huber
- Renal Division, University Hospital Freiburg, Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies, Albert-Ludwigs-University Freiburg, Germany
| | - Heiko M Reutter
- Institute of Human Genetics, University of Bonn, Bonn, Germany
- Department of Neonatology, Children’s Hospital, University of Bonn, Bonn, Germany
| | - Neveen A Soliman
- Department of Pediatrics, Kasr Al Ainy School of Medicine, Cairo University, Cairo, Egypt
- Egyptian Group for Orphan Renal Diseases (EGORD), Cairo, Egypt
| | - Natasa Stajic
- Medical Faculty, University of Belgrade, Belgrade, Serbia
- Institute of Mother and Child Healthcare of Serbia, Belgrade, Serbia
| | - Radovan Bogdanovic
- Medical Faculty, University of Belgrade, Belgrade, Serbia
- Institute of Mother and Child Healthcare of Serbia, Belgrade, Serbia
| | | | - Richard P Lifton
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
- Yale Center for Mendelian Genomics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Velibor Tasic
- Department of Pediatric Nephrology, University Children’s Hospital, Skopje, Macedonia
| | - Weining Lu
- Renal Section, Department of Medicine, Boston University Medical Center, Boston, MA, USA
| | - Friedhelm Hildebrandt
- Division of Nephrology, Department of Medicine, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
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16
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Fan L, Yan H, Pellegrin S, Mellor H. The Rif GTPase regulates cytoskeletal signaling from plexinA4 to promote neurite retraction. Neurosci Lett 2015; 590:178-83. [PMID: 25668492 DOI: 10.1016/j.neulet.2015.02.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 02/02/2015] [Accepted: 02/06/2015] [Indexed: 11/18/2022]
Abstract
The small GTPase Rif is required for the early stages of dendritic spine formation in neurons, acting through the formin mDia2 to control actin polymerization. Rif is expressed at high levels in the brain, suggesting broader roles in neuronal function. We screened a yeast two-hybrid cDNA library to identify additional binding partners for Rif of potential relevance to neuronal function. We found that Rif interacts with FARP1, a neuronal activator of the RhoA GTPase. We show that Rif has two separate roles in FARP1 regulation-in controlling its association with plexinA4, and in releasing active RhoA from a plexinA4/FARP1 complex. The regulation of FARP1 by Rif promotes neurite retraction in cells stimulated with the semaphorin Sema6A.
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Affiliation(s)
- Lifei Fan
- College of Life Sciences, Inner Mongolia University, University Road, Hohhot, China
| | - Huijuan Yan
- College of Life Sciences, Inner Mongolia University, University Road, Hohhot, China
| | - Stephanie Pellegrin
- School of Biochemistry, Medical Sciences Building, University Walk, University of Bristol, Bristol, UK
| | - Harry Mellor
- School of Biochemistry, Medical Sciences Building, University Walk, University of Bristol, Bristol, UK.
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17
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Xu Z, Zheng X, Yang L, Liu F, Zhang E, Duan W, Bai S, Safdar J, Li Z, Sun C. Chemokine receptor 7 promotes tumor migration and invasiveness via the RhoA/ROCK pathway in metastatic squamous cell carcinoma of the head and neck. Oncol Rep 2014; 33:849-55. [PMID: 25434638 DOI: 10.3892/or.2014.3631] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Accepted: 11/13/2014] [Indexed: 11/06/2022] Open
Abstract
Metastatic squamous cell carcinoma of the head and neck (SCCHN) has been shown to express chemokine receptor 7 (CCR7), which can activate signaling pathways to promote invasion and survival of SCCHN cells. We hypothesized that the RhoA/Rho-associated kinase (ROCK) pathway is involved in the CCR7-induced invasion and migration of metastatic SCCHN cells. Thus, using migration, matrigel invasion and scrape wound-healing assays, we elucidated the role of RhoA in mediating CCR7-associated cellular mobility. Pull-down assays and western blotting were used to measure RhoA and its downstream expression. Immunohistochemical staining and analysis were useful in identifying the correlation between CCR7 and RhoA expression and clinicopathological factors. The results showed that inhibition of RhoA/ROCK reduced the tumor cell migration and invasiveness induced by CCL19. Activated RhoA, proline-rich tyrosine kinase-2 (Pyk2) and cofilin induced by CCL19 were elevated, and increased RhoA, Pyk2 and cofilin activity was eliminated by CCR7mAb, RhoA/ROCK and Pyk2 inhibitors, indicating involvement of the RhoA/ROCK-Pyk2-cofilin cascade. In summary, CCR7 via RhoA/ROCK-Pyk2 cofilin pathway promotes invasion and migration of metastatic SCCHN cells.
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Affiliation(s)
- Zhongfei Xu
- Department of Oromaxillofacial-Head and Neck Surgery, School of Stomatology, China Medical University, Shenyang, Liaoning 110002, P.R. China
| | - Xiaojiao Zheng
- Department of Oromaxillofacial-Head and Neck Surgery, School of Stomatology, China Medical University, Shenyang, Liaoning 110002, P.R. China
| | - Liangliang Yang
- Department of Stomatology, The Fourth Affiliated Hospital of China Medical University, Shenyang, Liaoning 110002, P.R. China
| | - Fayu Liu
- Department of Oromaxillofacial-Head and Neck Surgery, School of Stomatology, China Medical University, Shenyang, Liaoning 110002, P.R. China
| | - Enjiao Zhang
- Department of Oromaxillofacial-Head and Neck Surgery, School of Stomatology, China Medical University, Shenyang, Liaoning 110002, P.R. China
| | - Weiyi Duan
- Department of Oromaxillofacial-Head and Neck Surgery, School of Stomatology, China Medical University, Shenyang, Liaoning 110002, P.R. China
| | - Shuang Bai
- Department of Oromaxillofacial-Head and Neck Surgery, School of Stomatology, China Medical University, Shenyang, Liaoning 110002, P.R. China
| | - Jawad Safdar
- Department of Oromaxillofacial-Head and Neck Surgery, School of Stomatology, China Medical University, Shenyang, Liaoning 110002, P.R. China
| | - Zhenning Li
- Department of Oromaxillofacial-Head and Neck Surgery, School of Stomatology, China Medical University, Shenyang, Liaoning 110002, P.R. China
| | - Changfu Sun
- Department of Oromaxillofacial-Head and Neck Surgery, School of Stomatology, China Medical University, Shenyang, Liaoning 110002, P.R. China
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18
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Cell type-specific Nogo-A gene ablation promotes axonal regeneration in the injured adult optic nerve. Cell Death Differ 2014; 22:323-35. [PMID: 25257170 DOI: 10.1038/cdd.2014.147] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 08/15/2014] [Accepted: 08/18/2014] [Indexed: 01/23/2023] Open
Abstract
Nogo-A is a well-known myelin-enriched inhibitory protein for axonal growth and regeneration in the central nervous system (CNS). Besides oligodendrocytes, our previous data revealed that Nogo-A is also expressed in subpopulations of neurons including retinal ganglion cells, in which it can have a positive role in the neuronal growth response after injury, through an unclear mechanism. In the present study, we analyzed the opposite roles of glial versus neuronal Nogo-A in the injured visual system. To this aim, we created oligodendrocyte (Cnp-Cre(+/-)xRtn4/Nogo-A(flox/flox)) and neuron-specific (Thy1-Cre(tg+)xRtn4(flox/flox)) conditional Nogo-A knock-out (KO) mouse lines. Following complete intraorbital optic nerve crush, both spontaneous and inflammation-mediated axonal outgrowth was increased in the optic nerves of the glia-specific Nogo-A KO mice. In contrast, neuron-specific deletion of Nogo-A in a KO mouse line or after acute gene recombination in retinal ganglion cells mediated by adeno-associated virus serotype 2.Cre virus injection in Rtn4(flox/flox) animals decreased axon sprouting in the injured optic nerve. These results therefore show that selective ablation of Nogo-A in oligodendrocytes and myelin in the optic nerve is more effective at enhancing regrowth of injured axons than what has previously been observed in conventional, complete Nogo-A KO mice. Our data also suggest that neuronal Nogo-A in retinal ganglion cells could participate in enhancing axonal sprouting, possibly by cis-interaction with Nogo receptors at the cell membrane that may counteract trans-Nogo-A signaling. We propose that inactivating Nogo-A in glia while preserving neuronal Nogo-A expression may be a successful strategy to promote axonal regeneration in the CNS.
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19
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Steenblock C, Heckel T, Czupalla C, Espírito Santo AI, Niehage C, Sztacho M, Hoflack B. The Cdc42 guanine nucleotide exchange factor FGD6 coordinates cell polarity and endosomal membrane recycling in osteoclasts. J Biol Chem 2014; 289:18347-59. [PMID: 24821726 DOI: 10.1074/jbc.m113.504894] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The initial step of bone digestion is the adhesion of osteoclasts onto bone surfaces and the assembly of podosomal belts that segregate the bone-facing ruffled membrane from other membrane domains. During bone digestion, membrane components of the ruffled border also need to be recycled after macropinocytosis of digested bone materials. How osteoclast polarity and membrane recycling are coordinated remains unknown. Here, we show that the Cdc42-guanine nucleotide exchange factor FGD6 coordinates these events through its Src-dependent interaction with different actin-based protein networks. At the plasma membrane, FGD6 couples cell adhesion and actin dynamics by regulating podosome formation through the assembly of complexes comprising the Cdc42-interactor IQGAP1, the Rho GTPase-activating protein ARHGAP10, and the integrin interactors Talin-1/2 or Filamin A. On endosomes and transcytotic vesicles, FGD6 regulates retromer-dependent membrane recycling through its interaction with the actin nucleation-promoting factor WASH. These results provide a mechanism by which a single Cdc42-exchange factor controlling different actin-based processes coordinates cell adhesion, cell polarity, and membrane recycling during bone degradation.
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Affiliation(s)
- Charlotte Steenblock
- From the Biotechnology Center, Technische Universität Dresden, Tatzberg 47-51, 01307 Dresden, Germany
| | - Tobias Heckel
- From the Biotechnology Center, Technische Universität Dresden, Tatzberg 47-51, 01307 Dresden, Germany
| | - Cornelia Czupalla
- From the Biotechnology Center, Technische Universität Dresden, Tatzberg 47-51, 01307 Dresden, Germany
| | - Ana Isabel Espírito Santo
- From the Biotechnology Center, Technische Universität Dresden, Tatzberg 47-51, 01307 Dresden, Germany
| | - Christian Niehage
- From the Biotechnology Center, Technische Universität Dresden, Tatzberg 47-51, 01307 Dresden, Germany
| | - Martin Sztacho
- From the Biotechnology Center, Technische Universität Dresden, Tatzberg 47-51, 01307 Dresden, Germany
| | - Bernard Hoflack
- From the Biotechnology Center, Technische Universität Dresden, Tatzberg 47-51, 01307 Dresden, Germany
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20
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Murk K, Blanco Suarez EM, Cockbill LMR, Banks P, Hanley JG. The antagonistic modulation of Arp2/3 activity by N-WASP, WAVE2 and PICK1 defines dynamic changes in astrocyte morphology. J Cell Sci 2013; 126:3873-83. [PMID: 23843614 PMCID: PMC3757329 DOI: 10.1242/jcs.125146] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/30/2013] [Indexed: 01/22/2023] Open
Abstract
Astrocytes exhibit a complex, branched morphology, allowing them to functionally interact with numerous blood vessels, neighboring glial processes and neuronal elements, including synapses. They also respond to central nervous system (CNS) injury by a process known as astrogliosis, which involves morphological changes, including cell body hypertrophy and thickening of major processes. Following severe injury, astrocytes exhibit drastically reduced morphological complexity and collectively form a glial scar. The mechanistic details behind these morphological changes are unknown. Here, we investigate the regulation of the actin-nucleating Arp2/3 complex in controlling dynamic changes in astrocyte morphology. In contrast to other cell types, Arp2/3 inhibition drives the rapid expansion of astrocyte cell bodies and major processes. This intervention results in a reduced morphological complexity of astrocytes in both dissociated culture and in brain slices. We show that this expansion requires functional myosin II downstream of ROCK and RhoA. Knockdown of the Arp2/3 subunit Arp3 or the Arp2/3 activator N-WASP by siRNA also results in cell body expansion and reduced morphological complexity, whereas depleting WAVE2 specifically reduces the branching complexity of astrocyte processes. By contrast, knockdown of the Arp2/3 inhibitor PICK1 increases astrocyte branching complexity. Furthermore, astrocyte expansion induced by ischemic conditions is delayed by PICK1 knockdown or N-WASP overexpression. Our findings identify a new morphological outcome for Arp2/3 activation in restricting rather than promoting outwards movement of the plasma membrane in astrocytes. The Arp2/3 regulators PICK1, and N-WASP and WAVE2 function antagonistically to control the complexity of astrocyte branched morphology, and this mechanism underlies the morphological changes seen in astrocytes during their response to pathological insult.
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Affiliation(s)
- Kai Murk
- School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Elena M. Blanco Suarez
- School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Louisa M. R. Cockbill
- School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Paul Banks
- School of Physiology and Pharmacology, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
| | - Jonathan G. Hanley
- School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK
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21
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Biased agonism of protease-activated receptor 1 by activated protein C caused by noncanonical cleavage at Arg46. Blood 2012; 120:5237-46. [PMID: 23149848 DOI: 10.1182/blood-2012-08-452169] [Citation(s) in RCA: 170] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Activated protein C (APC) exerts endothelial cytoprotective actions that require protease-activated receptor 1 (PAR1), whereas thrombin acting via PAR1 causes endothelial disruptive, proinflammatory actions. APC's activities, but not thrombin's, require PAR1 located in caveolae. PAR1 is a biased 7-transmembrane receptor because G proteins mediate thrombin's signaling, whereas β-arrestin 2 mediates APC's signaling. Here we elucidate novel mechanisms for APC's initiation of signaling. Biochemical studies of APC's protease specificity showed that APC cleaved PAR1 sequences at both Arg41 and Arg46. That PAR1 cleavage at Arg46 can occur on cells was supported by APC's cleavage of N-terminal-SEAP-tagged R41Q-PAR1 but not R41Q/R46Q-PAR1 mutants transfected into cells and by anti-PAR1 epitope mapping of APC-treated endothelial cells. A synthetic peptide composing PAR1 residues 47-66, TR47, stimulated protective signaling in endothelial cells as reflected in Akt and glycogen synthase kinase 3β phosphorylation, Ras-related C3 botulinum toxin substrate 1 activation, and barrier stabilization effects. In mice, the TR47 peptide reduced VEGF-induced vascular leakage. These in vitro and in vivo data imply that the novel PAR1 N-terminus beginning at residue Asn47, which is generated by APC cleavage at Arg46, mediates APC's cytoprotective signaling and that this unique APC-generated N-terminal peptide tail is a novel biased agonist for PAR1.
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22
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Herbert KJ, Snow ET. Modulation of arsenic-induced epidermal growth factor receptor pathway signalling by resveratrol. Chem Biol Interact 2012; 198:38-48. [PMID: 22634503 DOI: 10.1016/j.cbi.2012.05.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 05/15/2012] [Accepted: 05/15/2012] [Indexed: 01/12/2023]
Abstract
Arsenic (As) is both a human carcinogen and an effective anticancer drug. These aspects of arsenic toxicity develop as a consequence of arsenic-induced oxidative stress and modifications to signal pathway activity which alter gene expression. Resveratrol (RVL) a food antioxidant found in grapes and other fruits, exhibits anti-carcinogenic properties by reducing oxidative stress and restoring signal pathway control. This study investigated the impact of RVL on arsenite [As(III)]-induced cell signalling in HaCaT keratinocytes by assaying phosphorylation status of epidermal growth factor receptor (EGFR) signalling intermediates and measuring changes in expression of Phase II and DNA repair biomarkers. As(III) exposure produced dose-dependent toxicity which was associated with increased activation of EGFR pathway intermediates, cSrc, Rac1 and extracellular signal-regulated kinases 1 and 2 (ERK1/2). Arsenic-mediated ERK1/2 activation negatively regulated DNA polymerase beta expression and up regulated heme-oxygenase-1 at toxic concentrations. RVL treatment modulated As(III)-mediated ERK1/2 activation by shifting the balance of cSrc regulatory domain phosphorylation. These effects significantly altered the response of the EGFR pathway to growth factor-induced stimulation. Our research provides evidence that treatment with pharmacologically relevant doses of RVL influences cellular responses to As(III), largely due to RVL-mediated changes to Src and ERK1/2 activation.
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Affiliation(s)
- Katharine J Herbert
- School of Human Life Sciences, University of Tasmania, Launceston TAS 7248, Australia
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Sphingosine-1-phosphate enhances satellite cell activation in dystrophic muscles through a S1PR2/STAT3 signaling pathway. PLoS One 2012; 7:e37218. [PMID: 22606352 PMCID: PMC3351440 DOI: 10.1371/journal.pone.0037218] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 04/15/2012] [Indexed: 02/02/2023] Open
Abstract
Sphingosine-1-phosphate (S1P) activates a widely expressed family of G protein-coupled receptors, serves as a muscle trophic factor and activates muscle stem cells called satellite cells (SCs) through unknown mechanisms. Here we show that muscle injury induces dynamic changes in S1P signaling and metabolism in vivo. These changes include early and profound induction of the gene encoding the S1P biosynthetic enzyme SphK1, followed by induction of the catabolic enzyme sphingosine phosphate lyase (SPL) 3 days later. These changes correlate with a transient increase in circulating S1P levels after muscle injury. We show a specific requirement for SphK1 to support efficient muscle regeneration and SC proliferation and differentiation. Mdx mice, which serve as a model for muscular dystrophy (MD), were found to be S1P-deficient and exhibited muscle SPL upregulation, suggesting that S1P catabolism is enhanced in dystrophic muscle. Pharmacological SPL inhibition increased muscle S1P levels, improved mdx muscle regeneration and enhanced SC proliferation via S1P receptor 2 (S1PR2)-dependent inhibition of Rac1, thereby activating Signal Transducer and Activator of Transcription 3 (STAT3), a central player in inflammatory signaling. STAT3 activation resulted in p21 and p27 downregulation in a S1PR2-dependent fashion in myoblasts. Our findings suggest that S1P promotes SC progression through the cell cycle by repression of cell cycle inhibitors via S1PR2/STAT3-dependent signaling and that SPL inhibition may provide a therapeutic strategy for MD.
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Johnson JL, Monfregola J, Napolitano G, Kiosses WB, Catz SD. Vesicular trafficking through cortical actin during exocytosis is regulated by the Rab27a effector JFC1/Slp1 and the RhoA-GTPase-activating protein Gem-interacting protein. Mol Biol Cell 2012; 23:1902-16. [PMID: 22438581 PMCID: PMC3350554 DOI: 10.1091/mbc.e11-12-1001] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The mechanism of cytoskeleton remodeling during exocytosis is not well defined. A combination of vesicular dynamics and functional studies shows that the Rab27a effector JFC1 and the RhoA-GTPase–activating protein Gem-interacting protein are necessary for RhoA regulation, actin depolymerization, and vesicular transport through the actin cortex during exocytosis. Cytoskeleton remodeling is important for the regulation of vesicular transport associated with exocytosis, but a direct association between granular secretory proteins and actin-remodeling molecules has not been shown, and this mechanism remains obscure. Using a proteomic approach, we identified the RhoA-GTPase–activating protein Gem-interacting protein (GMIP) as a factor that associates with the Rab27a effector JFC1 and modulates vesicular transport and exocytosis. GMIP down-regulation induced RhoA activation and actin polymerization. Importantly, GMIP-down-regulated cells showed impaired vesicular transport and exocytosis, while inhibition of the RhoA-signaling pathway induced actin depolymerization and facilitated exocytosis. We show that RhoA activity polarizes around JFC1-containing secretory granules, suggesting that it may control directionality of granule movement. Using quantitative live-cell microscopy, we show that JFC1-containing secretory organelles move in areas near the plasma membrane deprived of polymerized actin and that dynamic vesicles maintain an actin-free environment in their surroundings. Supporting a role for JFC1 in RhoA inactivation and actin remodeling during exocytosis, JFC1 knockout neutrophils showed increased RhoA activity, and azurophilic granules were unable to traverse cortical actin in cells lacking JFC1. We propose that during exocytosis, actin depolymerization commences near the secretory organelle, not the plasma membrane, and that secretory granules use a JFC1- and GMIP-dependent molecular mechanism to traverse cortical actin.
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Affiliation(s)
- Jennifer L Johnson
- Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, CA 92037, USA
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25
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Niebel B, Weiche B, Mueller AL, Li DY, Karnowski N, Famulok M. A luminescent oxygen channeling biosensor that measures small GTPase activation. Chem Commun (Camb) 2011; 47:7521-3. [PMID: 21625685 DOI: 10.1039/c1cc11944c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We established a homogeneous luminescent oxygen channeling sensor for measuring activation states of small GTPases. The assay quantifies activated GTPases in cell lysates, can be applied to different GTPases, and can be used for multiplex screening. The study will provide guidelines for determining activation states of diverse GTPases in various biological contexts.
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Affiliation(s)
- Björn Niebel
- LIMES Institute, Chemical Biology & Medicinal Chemistry Unit, University of Bonn, 53121 Bonn, Germany
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26
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Perks CM, Burrows C, Holly JMP. Intrinsic, Pro-Apoptotic Effects of IGFBP-3 on Breast Cancer Cells are Reversible: Involvement of PKA, Rho, and Ceramide. Front Endocrinol (Lausanne) 2011; 2:13. [PMID: 22654794 PMCID: PMC3356103 DOI: 10.3389/fendo.2011.00013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 05/03/2011] [Indexed: 11/29/2022] Open
Abstract
We established previously that IGFBP-3 could exert positive or negative effects on cell function depending upon the extracellular matrix composition and by interacting with integrin signaling. To elicit its pro-apoptotic effects IGFBP-3 bound to caveolin-1 and the beta 1 integrin receptor and increased their association culminating in MAPK activation. Disruption of these complexes or blocking the beta 1 integrin receptor reversed these intrinsic actions of IGFBP-3. In this study we have examined the signaling pathway between integrin receptor binding and MAPK activation that mediates the intrinsic, pro-apoptotic actions of IGFBP-3. We found on inhibiting protein kinase A (PKA), Rho associated kinase (ROCK), and ceramide, the accentuating effects of IGFBP-3 on apoptotic triggers were reversed, such that IGFBP-3 then conferred cell survival. We established that IGFBP-3 activated Rho, the upstream regulator of ROCK and that beta1 integrin and PKA were upstream of Rho activation, whereas the involvement of ceramide was downstream. The beta 1 integrin, PKA, Rho, and ceramide were all upstream of MAPK activation. These data highlight key components involved in the pro-apoptotic effects of IGFBP-3 and that inhibiting them leads to a reversal in the action of IGFBP-3.
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Affiliation(s)
- Claire M. Perks
- *Correspondence: Claire M. Perks, IGF and Metabolic Endocrinology Group, Department of Clinical Sciences at North Bristol, The Medical School, Southmead Hospital, University of Bristol, Bristol, BS10 5NB, UK. e-mail:
| | - Carla Burrows
- IGFs and Metabolic Endocrinology Group, School of Clinical Sciences, Learning and Research Building, Southmead Hospital, University of BristolBristol, UK
| | - Jeff M. P. Holly
- IGFs and Metabolic Endocrinology Group, School of Clinical Sciences, Learning and Research Building, Southmead Hospital, University of BristolBristol, UK
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McIntosh J, Dennison G, Holly JMP, Jarrett C, Frankow A, Foulstone EJ, Winters ZE, Perks CM. IGFBP-3 can either inhibit or enhance EGF-mediated growth of breast epithelial cells dependent upon the presence of fibronectin. J Biol Chem 2010; 285:38788-800. [PMID: 20851879 DOI: 10.1074/jbc.m110.177311] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Progression of breast cancer is associated with remodeling of the extracellular matrix, often involving a switch from estrogen dependence to a dependence on EGF receptor (EGFR)/HER-2 and is accompanied by increased expression of the main binding protein for insulin-like growth factors (IGFBP-3). We have examined the effects of IGFBP-3 on EGF responses of breast epithelial cells in the context of changes in the extracellular matrix. On plastic and laminin with MCF-10A normal breast epithelial cells, EGF and IGFBP-3 each increased cell growth and together produced a synergistic response, whereas with T47D breast cancer cells IGFBP-3 alone had no effect, but the ability of EGF to increase cell proliferation was markedly inhibited in the presence of IGFBP-3. In contrast on fibronectin with MCF-10A cells, IGFBP-3 alone inhibited cell growth and blocked EGF-induced proliferation. With the cancer cells, IGFBP-3 alone had no effect but enhanced the EGF-induced increase in cell growth. The insulin-like growth factor-independent effects of IGFBP-3 alone on cell proliferation were completely abrogated in the presence of an EGFR, tyrosine kinase inhibitor, Iressa. Although IGFBP-3 did not affect EGFR phosphorylation [Tyr(1068)], it was found to modulate receptor internalization and was associated with activation of Rho and subsequent changes in MAPK phosphorylation. The levels of fibronectin and IGFBP-3 within breast tumors may determine their dependence on EGFR and their response to therapies targeting this receptor.
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Affiliation(s)
- Jamie McIntosh
- School of Clinical Sciences, IGFs and Metabolic Endocrinology Group, Learning and Research Building, 2nd Floor, University of Bristol, Southmead Hospital, Bristol BS10 5NB, United Kingdom
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28
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Nini L, Dagnino L. Accurate and reproducible measurements of RhoA activation in small samples of primary cells. Anal Biochem 2010; 398:135-7. [DOI: 10.1016/j.ab.2009.11.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Revised: 10/31/2009] [Accepted: 11/11/2009] [Indexed: 11/17/2022]
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29
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The fic domain: regulation of cell signaling by adenylylation. Mol Cell 2009; 34:93-103. [PMID: 19362538 DOI: 10.1016/j.molcel.2009.03.008] [Citation(s) in RCA: 209] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Revised: 02/12/2009] [Accepted: 03/20/2009] [Indexed: 11/22/2022]
Abstract
We show that the secreted antigen, IbpA, of the respiratory pathogen Histophilus somni induces cytotoxicity in mammalian cells via its Fic domains. Fic domains are defined by a core HPFxxGNGR motif and are conserved from bacteria to humans. We demonstrate that the Fic domains of IbpA catalyze a unique reversible adenylylation event that uses ATP to add an adenosine monophosphate (AMP) moiety to a conserved tyrosine residue in the switch I region of Rho GTPases. This modification requires the conserved histidine of the Fic core motif and renders Rho GTPases inactive. We further demonstrate that the only human protein containing a Fic domain, huntingtin yeast-interacting protein E (HYPE), also adenylylates Rho GTPases in vitro. Thus, we classify Fic domain-containing proteins as a class of enzymes that mediate bacterial pathogenesis as well as a previously unrecognized eukaryotic posttranslational modification that may regulate key signaling events.
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