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Chen J, Stark LA. Insights into the Relationship between Nucleolar Stress and the NF-κB Pathway. Trends Genet 2019; 35:768-780. [PMID: 31434627 DOI: 10.1016/j.tig.2019.07.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/22/2019] [Accepted: 07/24/2019] [Indexed: 02/06/2023]
Abstract
The nuclear organelle the nucleolus and the transcription factor nuclear factor of κ-light-chain-enhancer of activated B cells (NF-κB) are both central to the control of cellular homeostasis, dysregulated in common diseases and implicated in the ageing process. Until recently, it was believed that they acted independently to regulate homeostasis in health and disease. However, there is an emerging body of evidence suggesting that nucleoli and NF-κB signalling converge at multiple levels. Here we will review current understanding of this crosstalk. We will discuss activation of the NF-κB pathway by nucleolar stress and induction of apoptosis by nucleolar sequestration of NF-κB/RelA. We will also discuss the role of TIF-IA, COMMD1, and nucleophosmin, which are key players in this crosstalk, and the therapeutic relevance, particularly with respect to the antitumour effects of aspirin.
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Affiliation(s)
- Jingyu Chen
- University of Edinburgh Cancer Research Centre, Institute of Genetics and Molecular Medicine, Western General Hospital, Crewe Road, Edinburgh, Scotland EH4 2XU, UK
| | - Lesley A Stark
- University of Edinburgh Cancer Research Centre, Institute of Genetics and Molecular Medicine, Western General Hospital, Crewe Road, Edinburgh, Scotland EH4 2XU, UK.
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2
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Abdrabou A, Wang Z. Post-Translational Modification and Subcellular Distribution of Rac1: An Update. Cells 2018; 7:cells7120263. [PMID: 30544910 PMCID: PMC6316090 DOI: 10.3390/cells7120263] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 12/06/2018] [Accepted: 12/10/2018] [Indexed: 12/27/2022] Open
Abstract
Rac1 is a small GTPase that belongs to the Rho family. The Rho family of small GTPases is a subfamily of the Ras superfamily. The Rho family of GTPases mediate a plethora of cellular effects, including regulation of cytoarchitecture, cell size, cell adhesion, cell polarity, cell motility, proliferation, apoptosis/survival, and membrane trafficking. The cycling of Rac1 between the GTP (guanosine triphosphate)- and GDP (guanosine diphosphate)-bound states is essential for effective signal flow to elicit downstream biological functions. The cycle between inactive and active forms is controlled by three classes of regulatory proteins: Guanine nucleotide exchange factors (GEFs), GTPase-activating proteins (GAPs), and guanine-nucleotide-dissociation inhibitors (GDIs). Other modifications include RNA splicing and microRNAs; various post-translational modifications have also been shown to regulate the activity and function of Rac1. The reported post-translational modifications include lipidation, ubiquitination, phosphorylation, and adenylylation, which have all been shown to play important roles in the regulation of Rac1 and other Rho GTPases. Moreover, the Rac1 activity and function are regulated by its subcellular distribution and translocation. This review focused on the most recent progress in Rac1 research, especially in the area of post-translational modification and subcellular distribution and translocation.
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Affiliation(s)
- Abdalla Abdrabou
- Department of Medical Genetics, and Signal Transduction Research Group, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
| | - Zhixiang Wang
- Department of Medical Genetics, and Signal Transduction Research Group, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2H7, Canada.
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Öztürk E, Despot-Slade E, Pichler M, Zenobi-Wong M. RhoA activation and nuclearization marks loss of chondrocyte phenotype in crosstalk with Wnt pathway. Exp Cell Res 2017; 360:113-124. [PMID: 28865751 DOI: 10.1016/j.yexcr.2017.08.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 08/20/2017] [Accepted: 08/29/2017] [Indexed: 12/24/2022]
Abstract
De-differentiation comprises a major drawback for the use of autologous chondrocytes in cartilage repair. Here, we investigate the role of RhoA and canonical Wnt signaling in chondrocyte phenotype. Chondrocyte de-differentiation is accompanied by an upregulation and nuclear localization of RhoA. Effectors of canonical Wnt signaling including β-catenin and YAP/TAZ are upregulated in de-differentiating chondrocytes in a Rho-dependent manner. Inhibition of Rho activation with C3 transferase inhibits nuclear localization of RhoA, induces expression of chondrogenic markers on 2D and enhances the chondrogenic effect of 3D culturing. Upregulation of chondrogenic markers by Rho inhibition is accompanied by loss of canonical Wnt signaling markers in 3D or on 2D whereas treatment of chondrocytes with Wnt-3a abrogates this effect. However, induction of canonical Wnt signaling inhibits chondrogenic markers on 2D but enhances chondrogenic re-differentiation on 2D with C3 transferase or in 3D. These data provide insights on the context-dependent role of RhoA and Wnt signaling in de-differentiation and on mechanisms to induce chondrogenic markers for therapeutic approaches.
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Affiliation(s)
- Ece Öztürk
- Cartilage Engineering + Regeneration Laboratory, ETH Zurich, Otto-Stern-Weg 7, 8093 Zurich, Switzerland
| | - Evelin Despot-Slade
- Cartilage Engineering + Regeneration Laboratory, ETH Zurich, Otto-Stern-Weg 7, 8093 Zurich, Switzerland
| | - Michael Pichler
- Cartilage Engineering + Regeneration Laboratory, ETH Zurich, Otto-Stern-Weg 7, 8093 Zurich, Switzerland
| | - Marcy Zenobi-Wong
- Cartilage Engineering + Regeneration Laboratory, ETH Zurich, Otto-Stern-Weg 7, 8093 Zurich, Switzerland.
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Li Y, Hu Y, Che L, Jia J, Chen M. Nucleolar localization of Small G protein RhoA is associated with active RNA synthesis in human carcinoma HEp-2 cells. Oncol Lett 2016; 11:3605-3610. [PMID: 27313679 PMCID: PMC4888017 DOI: 10.3892/ol.2016.4450] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 03/01/2016] [Indexed: 01/09/2023] Open
Abstract
Previous studies have demonstrated that the nuclear localization of ras homolog family member A (RhoA), with prominent concentration in the nucleolus, is a common feature in human cancer tissues and cancer cell lines. Although a previous study has demonstrated that the nuclear translocation of RhoA occurs via active transport, a process that occurs through importin α in a nuclear factor-κB-dependent manner, the mechanism, biological function and pathological meaning of the nucleolar residency of RhoA remain to be elucidated. As the cell nucleolus is the site of ribosome biosynthesis, the aim of the present study was to investigate the association between RNA synthesis and the nucleolar localization of RhoA, as well as the molecular mechanisms underlying the residency of RhoA in the nucleolus of HEp-2 (human larynx epithelial carcinoma) cells. Indirect immunofluorescence microscopy was used to evaluate the subcellular distribution of nuclear RhoA, and immunoblotting analysis was used to determine the total cellular protein level of RhoA. Consistent with the results of previous studies, untreated HEp-2 cells exhibited bright nucleolar staining, indicating an increased concentration of RhoA in the nucleoli. Treatment with actinomycin D for the inhibition of RNA synthesis caused a redistribution of RhoA from the nucleoli to the nucleoplasm with a speckled staining pattern. Immunoblotting revealed that neither the total cellular amount of RhoA nor the integrity of RhoA was affected by treatment with actinomycin D. In cells that were treated at a decreased concentration (0.05 mg/l) of actinomycin D, the redistribution of RhoA was reversible following the removal of the drug from the culture medium. However, this reversal was not observed at an increased drug concentration (1 mg/l). Overall, to the best of our knowledge, the results of the present study provide the first in situ evidence that the inhibition of RNA synthesis induces a redistribution of nucleolar RhoA to the nucleoplasm, and additionally suggest that the nucleolar residency of RhoA in HEp-2 cells may be associated with active RNA synthesis.
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Affiliation(s)
- Yueying Li
- Department of Physiology, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China
| | - Yong Hu
- Department of Neonatology, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai 200040, P.R. China
| | - Lilong Che
- Department of Physiology, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China
| | - Junhai Jia
- Department of Physiology, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China
| | - Min Chen
- Department of Physiology, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu 212013, P.R. China
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Rohrbeck A, Fühner V, Schröder A, Hagemann S, Vu XK, Berndt S, Hust M, Pich A, Just I. Detection and Quantification of ADP-Ribosylated RhoA/B by Monoclonal Antibody. Toxins (Basel) 2016; 8:100. [PMID: 27043630 PMCID: PMC4848626 DOI: 10.3390/toxins8040100] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 03/20/2016] [Accepted: 03/29/2016] [Indexed: 01/03/2023] Open
Abstract
Clostridium botulinum exoenzyme C3 is the prototype of C3-like ADP-ribosyltransferases that modify the GTPases RhoA, B, and C. C3 catalyzes the transfer of an ADP-ribose moiety from the co-substrate nicotinamide adenine dinucleotide (NAD) to asparagine-41 of Rho-GTPases. Although C3 does not possess cell-binding/-translocation domains, C3 is able to efficiently enter intact cells, including neuronal and macrophage-like cells. Conventionally, the detection of C3 uptake into cells is carried out via the gel-shift assay of modified RhoA. Since this gel-shift assay does not always provide clear, evaluable results an additional method to confirm the ADP-ribosylation of RhoA is necessary. Therefore, a new monoclonal antibody has been generated that specifically detects ADP-ribosylated RhoA/B, but not RhoC, in Western blot and immunohistochemical assay. The scFv antibody fragment was selected by phage display using the human naive antibody gene libraries HAL9/10. Subsequently, the antibody was produced as scFv-Fc and was found to be as sensitive as a commercially available RhoA antibody providing reproducible and specific results. We demonstrate that this specific antibody can be successfully applied for the analysis of ADP-ribosylated RhoA/B in C3-treated Chinese hamster ovary (CHO) and HT22 cells. Moreover, ADP-ribosylation of RhoA was detected within 10 min in C3-treated CHO wild-type cells, indicative of C3 cell entry.
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Affiliation(s)
- Astrid Rohrbeck
- Institute of Toxicology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
| | - Viola Fühner
- Biotechnology and Bioinformatics, Department of Biotechnology, Institute for Biochemistry, Technische Universität Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany.
| | - Anke Schröder
- Institute of Toxicology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
| | - Sandra Hagemann
- Institute of Toxicology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
| | - Xuan-Khang Vu
- Institute of Toxicology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
| | - Sarah Berndt
- Institute of Toxicology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
| | - Michael Hust
- Biotechnology and Bioinformatics, Department of Biotechnology, Institute for Biochemistry, Technische Universität Braunschweig, Spielmannstr. 7, 38106 Braunschweig, Germany.
| | - Andreas Pich
- Institute of Toxicology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
| | - Ingo Just
- Institute of Toxicology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
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Tong J, Li L, Ballermann B, Wang Z. Phosphorylation and Activation of RhoA by ERK in Response to Epidermal Growth Factor Stimulation. PLoS One 2016; 11:e0147103. [PMID: 26816343 PMCID: PMC4729484 DOI: 10.1371/journal.pone.0147103] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 12/29/2015] [Indexed: 12/21/2022] Open
Abstract
The small GTPase RhoA has been implicated in various cellular activities, including the formation of stress fibers, cell motility, and cytokinesis. In addition to the canonical GTPase cycle, recent findings have suggested that phosphorylation further contributes to the tight regulation of Rho GTPases. Indeed, RhoA is phosphorylated on serine 188 (188S) by a number of protein kinases. We have recently reported that Rac1 is phosphorylated on threonine 108 (108T) by extracellular signal-regulated kinases (ERK) in response to epidermal growth factor (EGF) stimulation. Here, we provide evidence that RhoA is phosphorylated by ERK on 88S and 100T in response to EGF stimulation. We show that ERK interacts with RhoA and that this interaction is dependent on the ERK docking site (D-site) at the C-terminus of RhoA. EGF stimulation enhanced the activation of the endogenous RhoA. The phosphomimetic mutant, GFP-RhoA S88E/T100E, when transiently expressed in COS-7 cells, displayed higher GTP-binding than wild type RhoA. Moreover, the expression of GFP-RhoA S88E/T100E increased actin stress fiber formation in COS-7 cells, which is consistent with its higher activity. In contrast to Rac1, phosphorylation of RhoA by ERK does not target RhoA to the nucleus. Finally, we show that regardless of the phosphorylation status of RhoA and Rac1, substitution of the RhoA PBR with the Rac1 PBR targets RhoA to the nucleus and substitution of Rac1 PBR with RhoA PBR significantly reduces the nuclear localization of Rac1. In conclusion, ERK phosphorylates RhoA on 88S and 100T in response to EGF, which upregulates RhoA activity.
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Affiliation(s)
- Junfeng Tong
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
- Signal Transduction Research Group, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
| | - Laiji Li
- Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
- Signal Transduction Research Group, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
| | - Barbara Ballermann
- Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
- Signal Transduction Research Group, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
| | - Zhixiang Wang
- Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
- Signal Transduction Research Group, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, T6G 2H7, Canada
- * E-mail:
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Li H, Wang Z, Zhang W, Qian K, Xu W, Zhang S. Fbxw7 regulates tumor apoptosis, growth arrest and the epithelial-to-mesenchymal transition in part through the RhoA signaling pathway in gastric cancer. Cancer Lett 2015; 370:39-55. [PMID: 26458995 DOI: 10.1016/j.canlet.2015.10.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 09/12/2015] [Accepted: 10/03/2015] [Indexed: 11/30/2022]
Abstract
F-box and WD repeat domain-containing7 (Fbxw7), a member of the F-box family of proteins, which are components of an E3 ubiquitin ligase complex, plays an important role as a general tumor suppressor in regulating the effects of various oncoproteins. Recently, accumulating studies have shown that Fbxw7 plays an important role in tumor cell motility, invasion and cancer metastasis. However, little is known about the signaling mechanisms that regulate tumor apoptosis, growth arrest and the epithelial-to-mesenchymal transition (EMT) in gastric cancer. In our study, we confirmed that Fbxw7 expression was decreased in gastric cancer tissues, and that Fbxw7 inhibited gastric cancer progression by inducing apoptosis and growth arrest. Furthermore, gastric cancer migration and invasion were decreased or increased following Fbxw7 overexpression or knockdown, respectively, and the expressions of various EMT markers, such as E-cadherin, N-cadherin and vimentin, were altered after Fbxw7 inhibition or overexpression. Furthermore, we demonstrated that Fbxw7 inhibits the EMT via the down-regulation of Snail 1 and ZEB 1, which are upstream transcription factors that promote this process. Additionally, RhoA showed higher expression in the same gastric cancer tissues than in normal tumor-adjacent samples. We found that Fbxw7 expression was negatively correlated with RhoA protein expression in gastric cancer tissues based on Pearson's correlation coefficient analysis. Moreover, we found that RhoA protein abundance was regulated by Fbxw7 via ubiquitination and proteasomal degradation in gastric cancer. We further demonstrated the effects of RhoA re-expression or inhibition on stable Fbxw7-overexpressing or Fbxw7-silenced cell lines in vitro and in vivo. These results suggest that Fbxw7 induces apoptosis and growth arrest and inhibits the EMT in part by down-regulating the RhoA signaling pathway.
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Affiliation(s)
- Hui Li
- Department of Gastrointestinal Surgery, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China
| | - Ziwei Wang
- Department of Gastrointestinal Surgery, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China.
| | - Wei Zhang
- Department of Gastrointestinal Surgery, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China
| | - Kun Qian
- Department of Gastrointestinal Surgery, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China
| | - Wei Xu
- Department of Gastrointestinal Surgery, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China
| | - Shouru Zhang
- Department of Gastrointestinal Surgery, The First Affiliated Hospital, Chongqing Medical University, Chongqing 400016, China
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Ma S, Deng J, Li B, Li X, Yan Z, Zhu J, Chen G, Wang Z, Jiang H, Miao L, Li J. Development of Second-Generation Small-Molecule RhoA Inhibitors with Enhanced Water Solubility, Tissue Potency, and Significant in vivo Efficacy. ChemMedChem 2014; 10:193-206. [DOI: 10.1002/cmdc.201402386] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Indexed: 12/24/2022]
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