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Hildebrandt ER, Hussain SA, Sieburg MA, Ravishankar R, Asad N, Gore S, Ito T, Hougland JL, Dore TM, Schmidt WK. Targeted genetic and small molecule disruption of N-Ras CaaX cleavage alters its localization and oncogenic potential. Bioorg Chem 2024; 147:107316. [PMID: 38583246 PMCID: PMC11098683 DOI: 10.1016/j.bioorg.2024.107316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/16/2024] [Accepted: 03/26/2024] [Indexed: 04/09/2024]
Abstract
Ras GTPases and other CaaX proteins undergo multiple post-translational modifications at their carboxyl-terminus. These events initiate with prenylation of a cysteine and are followed by endoproteolytic removal of the 'aaX' tripeptide and carboxylmethylation. Some CaaX proteins are only subject to prenylation, however, due to the presence of an uncleavable sequence. In this study, uncleavable sequences were used to stage Ras isoforms in a farnesylated and uncleaved state to address the impact of CaaX proteolysis on protein localization and function. This targeted strategy is more specific than those that chemically inhibit the Rce1 CaaX protease or delete the RCE1 gene because global abrogation of CaaX proteolysis impacts the entire CaaX protein proteome and effects cannot be attributed to any specific CaaX protein of the many concurrently affected. With this targeted strategy, clear mislocalization and reduced activity of farnesylated and uncleaved Ras isoforms was observed. In addition, new peptidomimetics based on cleavable Ras CaaX sequences and the uncleavable CAHQ sequence were synthesized and tested as Rce1 inhibitors using in vitro and cell-based assays. Consistently, these non-hydrolyzable peptidomimetic Rce1 inhibitors recapitulate Ras mislocalization effects when modeled on cleavable but not uncleavable CaaX sequences. These findings indicate that a prenylated and uncleavable CaaX sequence, which can be easily applied to a wide range of mammalian CaaX proteins, can be used to probe the specific impact of CaaX proteolysis on CaaX protein properties under conditions of an otherwise normally processed CaaX protein proteome.
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Affiliation(s)
- Emily R Hildebrandt
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA, USA
| | - Shaneela A Hussain
- New York University Abu Dhabi, Saadiyat Island, PO Box 129188, Abu Dhabi, UAE
| | | | - Rajani Ravishankar
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA, USA
| | - Nadeem Asad
- New York University Abu Dhabi, Saadiyat Island, PO Box 129188, Abu Dhabi, UAE
| | - Sangram Gore
- New York University Abu Dhabi, Saadiyat Island, PO Box 129188, Abu Dhabi, UAE
| | - Takahiro Ito
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA, USA
| | - James L Hougland
- Department of Chemistry, Syracuse University, Syracuse, NY, USA; Department of Biology, Syracuse University, Syracuse, NY, USA; BioInspired Syracuse, Syracuse University, Syracuse, NY, USA
| | - Timothy M Dore
- New York University Abu Dhabi, Saadiyat Island, PO Box 129188, Abu Dhabi, UAE; Department of Chemistry, University of Georgia, Athens, GA, USA
| | - Walter K Schmidt
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA, USA.
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2
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Jayadev R, Chi Q, Sherwood DR. Post-embryonic endogenous expression and localization of LET-60/Ras in C. elegans. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000931. [PMID: 37692087 PMCID: PMC10492041 DOI: 10.17912/micropub.biology.000931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/17/2023] [Accepted: 08/25/2023] [Indexed: 09/12/2023]
Abstract
Ras GTPases regulate many developmental and physiological processes and mutations in Ras are associated with numerous human cancers. Here, we report the function, levels, and localization of an N-terminal knock-in of mNeonGreen (mNG) into C. elegans LET-60 /Ras. mNG:: LET-60 interferes with some but not all LET-60 /Ras functions. mNG:: LET-60 is broadly present in tissues, found at different levels in cells, and concentrates in distinct subcellular compartments, including the nucleolus, nucleus, intracellular region, and plasma membrane. These results suggest that mNG:: LET-60 can be a useful tool for determining LET-60 levels and localization once its functionality in a developmental or physiological process is established.
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Affiliation(s)
| | - Qiuyi Chi
- Department of Biology, Duke University, Durham, NC, USA
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3
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Phenotypic Switching of Naïve T Cells to Immune-Suppressive Treg-Like Cells by Mutant KRAS. J Clin Med 2019; 8:jcm8101726. [PMID: 31635338 PMCID: PMC6832522 DOI: 10.3390/jcm8101726] [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: 09/12/2019] [Revised: 10/09/2019] [Accepted: 10/15/2019] [Indexed: 12/30/2022] Open
Abstract
Oncogenic (mutant) Ras protein Kirsten rat sarcoma viral oncogene homolog (KRAS) promotes uncontrolled proliferation, altered metabolism, and loss of genome integrity in a cell-intrinsic manner. Here, we demonstrate that CD4+ T cells when incubated with tumor-derived exosomes from mutant (MT) KRAS non-small-cell lung cancer (NSCLC) cells, patient sera, or a mouse xenograft model, induce phenotypic conversion to FOXP3+ Treg-like cells that are immune-suppressive. Furthermore, transfecting T cells with MT KRAS cDNA alone induced phenotypic switching and mathematical modeling supported this conclusion. Single-cell sequencing identified the interferon pathway as the mechanism underlying the phenotypic switch. These observations highlight a novel cytokine-independent, cell-extrinsic role for KRAS in T cell phenotypic switching. Thus, targeting this new class of Tregs represents a unique therapeutic approach for NSCLC. Since KRAS is the most frequently mutated oncogene in a wide variety of cancers, the findings of this investigation are likely to be of broad interest and have a large scientific impact.
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Tiwari A, Rebholz S, Maier E, Dehghan Harati M, Zips D, Sers C, Rodemann HP, Toulany M. Stress-Induced Phosphorylation of Nuclear YB-1 Depends on Nuclear Trafficking of p90 Ribosomal S6 Kinase. Int J Mol Sci 2018; 19:ijms19082441. [PMID: 30126195 PMCID: PMC6121600 DOI: 10.3390/ijms19082441] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 08/14/2018] [Accepted: 08/17/2018] [Indexed: 12/24/2022] Open
Abstract
Ionizing radiation (IR) and epidermal growth factor (EGF) stimulate Y-box binding protein-1 (YB-1) phosphorylation at Ser-102 in KRAS wild-type (KRASwt) cells, whereas in KRAS mutated (KRASmut) cells, YB-1 is constitutively phosphorylated, independent of IR or EGF. YB-1 activity stimulates the repair of IR-induced DNA double-strand breaks (DSBs) in the nucleus. Thus far, the YB-1 nuclear translocation pattern after cell exposure to various cellular stressors is not clear. In the present study, we investigated the pattern of YB-1 phosphorylation and its possible translocation to the nucleus in KRASwt cells after exposure to IR, EGF treatment, and conditional expression of mutated KRAS(G12V). IR, EGF, and conditional KRAS(G12V) expression induced YB-1 phosphorylation in both the cytoplasmic and nuclear fractions of KRASwt cells. None of the stimuli induced YB-1 nuclear translocation, while p90 ribosomal s6 kinase (RSK) translocation was enhanced in KRASwt cells after any of the stimuli. EGF-induced RSK translocation to the nucleus and nuclear YB-1 phosphorylation were completely blocked by the EGF receptor kinase inhibitor erlotinib. Likewise, RSK inhibition blocked RSK nuclear translocation and nuclear YB-1 phosphorylation after irradiation and KRAS(G12V) overexpression. In summary, acute stimulation of YB-1 phosphorylation does not lead to YB-1 translocation from the cytoplasm to the nucleus. Rather, irradiation, EGF treatment, or KRAS(G12V) overexpression induces RSK activation, leading to its translocation to the nucleus, where it activates already-existing nuclear YB-1. Our novel finding illuminates the signaling pathways involved in nuclear YB-1 phosphorylation and provides a rationale for designing appropriate targeting strategies to block YB-1 in oncology as well as in radiation oncology.
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Affiliation(s)
- Aadhya Tiwari
- Division of Radiobiology & Molecular Environmental Research, Department of Radiation Oncology, University of Tuebingen, Tuebingen, Germany.
- German Consortium for Translational Cancer Research (DKTK), Partner Site Tuebingen and German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Simone Rebholz
- Division of Radiobiology & Molecular Environmental Research, Department of Radiation Oncology, University of Tuebingen, Tuebingen, Germany.
- German Consortium for Translational Cancer Research (DKTK), Partner Site Tuebingen and German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Eva Maier
- Division of Radiobiology & Molecular Environmental Research, Department of Radiation Oncology, University of Tuebingen, Tuebingen, Germany.
- German Consortium for Translational Cancer Research (DKTK), Partner Site Tuebingen and German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Mozhgan Dehghan Harati
- Division of Radiobiology & Molecular Environmental Research, Department of Radiation Oncology, University of Tuebingen, Tuebingen, Germany.
- German Consortium for Translational Cancer Research (DKTK), Partner Site Tuebingen and German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Daniel Zips
- Division of Radiobiology & Molecular Environmental Research, Department of Radiation Oncology, University of Tuebingen, Tuebingen, Germany.
- German Consortium for Translational Cancer Research (DKTK), Partner Site Tuebingen and German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Christine Sers
- Laboratory of Molecular Tumor Pathology and Systems Biology, Institute of Pathology, Charité Universitätsmedizin Berlin, Berlin, Germany.
- German Consortium for Translational Cancer Research (DKTK), Partner Site Berlin and German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - H Peter Rodemann
- Division of Radiobiology & Molecular Environmental Research, Department of Radiation Oncology, University of Tuebingen, Tuebingen, Germany.
- German Consortium for Translational Cancer Research (DKTK), Partner Site Tuebingen and German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Mahmoud Toulany
- Division of Radiobiology & Molecular Environmental Research, Department of Radiation Oncology, University of Tuebingen, Tuebingen, Germany.
- German Consortium for Translational Cancer Research (DKTK), Partner Site Tuebingen and German Cancer Research Center (DKFZ), Heidelberg, Germany.
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5
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Ritchie C, Mack A, Harper L, Alfadhli A, Stork PJS, Nan X, Barklis E. Analysis of K-Ras Interactions by Biotin Ligase Tagging. Cancer Genomics Proteomics 2018. [PMID: 28647697 DOI: 10.21873/cgp.20034] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Mutations of the human K-Ras 4B (K-Ras) G protein are associated with a significant proportion of all human cancers. Despite this fact, a comprehensive analysis of K-Ras interactions is lacking. Our investigations focus on characterization of the K-Ras interaction network. MATERIALS AND METHODS We employed a biotin ligase-tagging approach, in which tagged K-Ras proteins biotinylate neighbor proteins in a proximity-dependent fashion, and proteins are identified via mass spectrometry (MS) sequencing. RESULTS In transfected cells, a total of 748 biotinylated proteins were identified from cells expressing biotin ligase-tagged K-Ras variants. Significant differences were observed between membrane-associated variants and a farnesylation-defective mutant. In pancreatic cancer cells, 56 K-Ras interaction partners were identified. Most of these were cytoskeletal or plasma membrane proteins, and many have been identified previously as potential cancer biomarkers. CONCLUSION Biotin ligase tagging offers a rapid and convenient approach to the characterization of K-Ras interaction networks.
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Affiliation(s)
- Christopher Ritchie
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR, U.S.A
| | - Andrew Mack
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR, U.S.A
| | - Logan Harper
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR, U.S.A
| | - Ayna Alfadhli
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR, U.S.A
| | - Philip J S Stork
- Department of Vollum Institute, Oregon Health & Science University, Portland, OR, U.S.A
| | - Xiaolin Nan
- Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR, U.S.A
| | - Eric Barklis
- Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR, U.S.A.
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Ahmed HH, El-Abhar HS, Hassanin EAK, Abdelkader NF, Shalaby MB. Ginkgo biloba L. leaf extract offers multiple mechanisms in bridling N-methylnitrosourea – mediated experimental colorectal cancer. Biomed Pharmacother 2017; 95:387-393. [DOI: 10.1016/j.biopha.2017.08.103] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 08/19/2017] [Accepted: 08/23/2017] [Indexed: 12/11/2022] Open
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7
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Ahmed HH, El-Abhar HS, Hassanin EAK, Abdelkader NF, Shalaby MB. Punica granatum suppresses colon cancer through downregulation of Wnt/β-Catenin in rat model. REVISTA BRASILEIRA DE FARMACOGNOSIA-BRAZILIAN JOURNAL OF PHARMACOGNOSY 2017. [DOI: 10.1016/j.bjp.2017.05.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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8
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Muñoz-Félix JM, Fuentes-Calvo I, Cuesta C, Eleno N, Crespo P, López-Novoa JM, Martínez-Salgado C. Absence of K-Ras Reduces Proliferation and Migration But Increases Extracellular Matrix Synthesis in Fibroblasts. J Cell Physiol 2016; 231:2224-35. [PMID: 26873620 DOI: 10.1002/jcp.25340] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 02/10/2016] [Indexed: 02/06/2023]
Abstract
The involvement of Ras-GTPases in the development of renal fibrosis has been addressed in the last decade. We have previously shown that H- and N-Ras isoforms participate in the regulation of fibrosis. Herein, we assessed the role of K-Ras in cellular processes involved in the development of fibrosis: proliferation, migration, and extracellular matrix (ECM) proteins synthesis. K-Ras knockout (KO) mouse embryonic fibroblasts (K-ras(-/-) ) stimulated with transforming growth factor-β1 (TGF-β1) exhibited reduced proliferation and impaired mobility than wild-type fibroblasts. Moreover, an increase on ECM production was observed in K-Ras KO fibroblasts in basal conditions. The absence of K-Ras was accompanied by reduced Ras activation and ERK phosphorylation, and increased AKT phosphorylation, but no differences were observed in TGF-β1-induced Smad signaling. The MEK inhibitor U0126 decreased cell proliferation independently of the presence of K-ras but reduced migration and ECM proteins expression only in wild-type fibroblasts, while the PI3K-AKT inhibitor LY294002 decreased cell proliferation, migration, and ECM synthesis in both types of fibroblasts. Thus, our data unveil that K-Ras and its downstream effector pathways distinctively regulate key biological processes in the development of fibrosis. Moreover, we show that K-Ras may be a crucial mediator in TGF-β1-mediated effects in this cell type. J. Cell. Physiol. 231: 2224-2235, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- José M Muñoz-Félix
- Unidad de Fisiopatología Renal y Cardiovascular, Departamento de Fisiología y Farmacología, Instituto "Reina Sofía" de Investigación Nefrológica, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Isabel Fuentes-Calvo
- Unidad de Fisiopatología Renal y Cardiovascular, Departamento de Fisiología y Farmacología, Instituto "Reina Sofía" de Investigación Nefrológica, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Cristina Cuesta
- Unidad de Fisiopatología Renal y Cardiovascular, Departamento de Fisiología y Farmacología, Instituto "Reina Sofía" de Investigación Nefrológica, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Nélida Eleno
- Unidad de Fisiopatología Renal y Cardiovascular, Departamento de Fisiología y Farmacología, Instituto "Reina Sofía" de Investigación Nefrológica, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Piero Crespo
- Facultad de Medicina, Departamento de Biología Molecular, Instituto de Biomedicina y Biotecnología de Cantabria, Consejo Superior de Investigaciones Científicas-IDICAN-Universidad de Cantabria, Santander, Spain
| | - José M López-Novoa
- Unidad de Fisiopatología Renal y Cardiovascular, Departamento de Fisiología y Farmacología, Instituto "Reina Sofía" de Investigación Nefrológica, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain
| | - Carlos Martínez-Salgado
- Unidad de Fisiopatología Renal y Cardiovascular, Departamento de Fisiología y Farmacología, Instituto "Reina Sofía" de Investigación Nefrológica, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Salamanca, Spain.,Instituto de Estudios de Ciencias de la Salud de Castilla y León (IECSCYL), Unidad de Investigación, Hospital Universitario de Salamanca, Salamanca, Spain
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Abstract
According to the standard model of G protein-coupled receptor (GPCR) signaling, GPCRs are localized to the cell membrane where they respond to extracellular signals. Stimulation of GPCRs leads to the activation of heterotrimeric G proteins and their intracellular signaling pathways. However, this model fails to accommodate GPCRs, G proteins, and their downstream effectors that are found on the nuclear membrane or in the nucleus. Evidence from isolated nuclei indicates the presence of GPCRs on the nuclear membrane that can activate similar G protein-dependent signaling pathways in the nucleus as at the cell surface. These pathways also include activation of cyclic adenosine monophosphate, calcium and nitric oxide synthase signaling in cardiomyocytes. In addition, a number of distinct heterotrimeric and monomeric G proteins have been found in the nucleus of various cell types. This review will focus on understanding the function of nuclear G proteins with a focus on cardiac signaling where applicable.
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10
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Arkowitz RA, Bassilana M. Regulation of hyphal morphogenesis by Ras and Rho small GTPases. FUNGAL BIOL REV 2015. [DOI: 10.1016/j.fbr.2015.02.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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11
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ALK1 heterozygosity increases extracellular matrix protein expression, proliferation and migration in fibroblasts. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:1111-22. [DOI: 10.1016/j.bbamcr.2014.02.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 02/19/2014] [Accepted: 02/23/2014] [Indexed: 11/16/2022]
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Abstract
For centuries yeast species have been popular hosts for classical biotechnology processes, such as baking, brewing, and wine making, and more recently for recombinant proteins production, thanks to the advantages of unicellular organisms (i.e., ease of genetic manipulation and rapid growth) together with the ability to perform eukaryotic posttranslational modifications. Moreover, yeast cells have been used for few decades as a tool for identifying the genes and pathways involved in basic cellular processes such as the cell cycle, aging, and stress response. In the budding yeast S. cerevisiae the Ras/cAMP/PKA pathway is directly involved in the regulation of metabolism, cell growth, stress resistance, and proliferation in response to the availability of nutrients and in the adaptation to glucose, controlling cytosolic cAMP levels and consequently the cAMP-dependent protein kinase (PKA) activity. Moreover, Ras signalling has been identified in several pathogenic yeasts as a key controller for virulence, due to its involvement in yeast morphogenesis. Nowadays, yeasts are still useful for Ras-like proteins investigation, both as model organisms and as a test tube to study variants of heterologous Ras-like proteins.
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Affiliation(s)
- Renata Tisi
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
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13
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Abstract
AbstractRas genes are pre-eminent genes that are frequently linked with cancer biology. The functional loss of ras protein caused by various point mutations within the gene, is established as a prognostic factor for the genesis of a constitutively active Ras-MAPK pathway leading to cancer. Ras signaling circuit follows a complex pathway, which connects many signaling molecules and cells. Several strategies have come up for targeting mutant ras proteins for cancer therapy, however, the clinical benefits remain insignificant. Targeting the Ras-MAPK pathway is extremely complicated due its intricate networks involving several upstream and downstream regulators. Blocking oncogenic Ras is still in latent stage and requires alternative approaches to screen the genes involved in Ras transformation. Understanding the mechanism of Ras induced tumorigenesis in diverse cancers and signaling networks will open a path for drug development and other therapeutic approaches.
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14
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Broggi S, Martegani E, Colombo S. Live-cell imaging of endogenous Ras-GTP shows predominant Ras activation at the plasma membrane and in the nucleus in Saccharomyces cerevisiae. Int J Biochem Cell Biol 2012; 45:384-94. [PMID: 23127800 DOI: 10.1016/j.biocel.2012.10.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 10/02/2012] [Accepted: 10/25/2012] [Indexed: 10/27/2022]
Abstract
Ras proteins function as a point of convergence for different signalling pathways in eukaryotes and are involved in many cellular responses; their different subcellular locations could regulate distinct functions. To investigate the localization of active Ras in vivo in Saccharomyces cerevisiae, we expressed a probe consisting of a GFP fusion with a trimeric Ras binding domain of Raf1 (eGFP-RBD3), which binds Ras-GTP with a much higher affinity than Ras-GDP. Our results show that in wild type cells active Ras accumulates mainly at the plasma membrane and in the nucleus during growth on medium containing glucose, while it accumulates mainly in mitochondria in wild type glucose-starved cells and relocalizes to the plasma membrane and to the nucleus upon addition of this sugar. A similar pattern is observed in a strain deleted in the CYR1 gene indicating that the absence of adenylate cyclase does not impair the localization of Ras-GTP. Remarkably, in a gpa2Δ, but not in a gpr1Δ mutant, active Ras accumulates in internal membranes and mitochondria, both when cells are growing on glucose medium or are starved, indicating that Gpa2, but not Gpr1 is required for the recruitment of Ras-GTP at the plasma membrane and in the nucleus. Moreover, deletion of both HXK1 and HXK2 also causes a mitochondrial localization of the probe, which relocalizes to the plasma membrane and to the nucleus upon expression of HXK2 on a centromeric plasmid, suggesting that this kinase is involved in the proper localization of active Ras.
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Affiliation(s)
- Serena Broggi
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
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15
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Ferreira L, Fuentes-Calvo I, Muñoz-Félix JM, Muñiz-Martín C, Sánchez-Juanes F, Raposo C, González-Buitrago JM, López-Novoa JM, Martínez-Salgado C. Functional specific roles of H-ras and N-ras. A proteomic approach using knockout cell lines. Electrophoresis 2012; 33:1385-96. [PMID: 22648805 DOI: 10.1002/elps.201100606] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Ras small GTPases function as transducers of extracellular signals regulating cell survival, growth and differentiation. There are three major ras isoforms: H-, N- and K-Ras. To improve the understanding of H- and N-Ras protein signalling networks, we compared total proteome changes in mouse embryonic fibroblasts knock out for H-ras and/or N-ras, using proteomics tools combining 2DE, semi-quantitative image analysis, in-gel trypsin digestion and mass spectrometry. There are four up-regulated proteins due to the loss of expression of H-Ras (including cyclin-dependent kinase inhibitor 2A) and eight down-regulated (including stress-70 protein, dihydropyrimidinase-related-protein 3, heat shock cognate 71 kDa protein, tropomyosin beta chain, Rho GDP-dissociation inhibitor 1) and six up-regulated proteins (e.g. leukocyte elastase inhibitor A, L-lactate dehydrogenase B chain, c-Myc-responsive protein Rcl, interleukin-1 receptor antagonist protein) due to the loss of expression of both N- and H-Ras. Most of these proteins are related to Ras signalling in one way or another. Changes in expression of some of these proteins were further confirmed by Western blot. This proteomic comparative analysis from loss of function of H- and N-Ras knockout fibroblasts yields interpretable data to elucidate the differential protein expression, and contributes to evaluate the possibilities for physiological and therapeutic targets.
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Affiliation(s)
- Laura Ferreira
- Unidad de Investigación, Hospital Universitario de Salamanca, Spain
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16
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Contente S, Yeh TJA, Friedman RM. H-ras localizes to cell nuclei and varies with the cell cycle. Genes Cancer 2011; 2:166-72. [PMID: 21779490 PMCID: PMC3111243 DOI: 10.1177/1947601911405042] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 02/18/2011] [Accepted: 03/04/2011] [Indexed: 01/10/2023] Open
Abstract
H-Ras functions as a signal switch molecule in numerous signaling pathways in the cytoplasm, requiring H-Ras localization to the inner surface of the cytoplasmic membrane, and H-Ras is considered to be a cytoplasmic protein. Immunoblot studies of cells transformed by overexpression of c-H-ras indicated that H-Ras protein was present in both cytoplasmic and nuclear extracts, suggesting a possible correlation of nuclear H-Ras and cellular transformation. Unexpectedly, additional studies revealed that H-Ras protein was also present in the nuclei of nontransformed and primary mouse cells, which do not overexpress H-Ras. Mouse fibroblast NIH 3T3 cells, L cells, and a primary fibroblast line all had H-Ras present in both cytoplasmic and nuclear extracts. Nuclear extracts of cells synchronized by growth without serum displayed an increasing amount of H-Ras and cyclin D1 as cells grew after serum addition. Treatment with farnesyltransferase inhibitor caused loss of H-Ras from the nucleus. Immunofluorescence in situ studies of nuclei from synchronized cultures showed that H-Ras protein appeared in and disappeared from the nuclei as the cells moved through the growth cycle. This cycling occurred in both nontransformed and ras-transformed cells. Flow cytometry measurements on parallel cultures revealed that the time point at which the greatest percentage of cells were in S phase, for each line, corresponded to appearance of a noticeably stronger in situ signal for H-Ras. H-Ras may participate in nuclear signaling pathways associated with replication in addition to its cytoplasmic signaling functions.
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Affiliation(s)
- Sara Contente
- Department of Pathology, F. Edward Hébert School of Medicine, and United States Military Cancer Institute, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
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EphrinA1 inhibits malignant mesothelioma tumor growth via let-7 microRNA-mediated repression of the RAS oncogene. Cancer Gene Ther 2011; 18:806-16. [PMID: 21869823 DOI: 10.1038/cgt.2011.50] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
EphrinA1 binding with receptor EphA2 suppresses malignant mesothelioma (MM) growth. The mechanisms whereby EphrinA1 attenuates the MM cell (MMC) growth are not clear. In this study, we report that the activation of MMCs with EphrinA1 leads to an induction of let-7 microRNA (miRNA) expression, repression of RAS proto-oncogene and the attenuation of MM tumor growth. The expression of miRNAs was determined by reverse transcription-quantitative polymerase chain reaction and in situ hybridization. RAS expression was determined by q-PCR, western blotting and immunofluorescence. MMC proliferation and tumor growth were determined by WST-1 and Matrigel assay, respectively. EphrinA1 activation induced several fold increases in let-7a1, let-7a3, let-7f1 and let-7f2 miRNA expression in MMCs. In contrast, EphrinA1 activation significantly downregulated H-RAS, K-RAS and N-RAS expression and inhibited MMC proliferation and tumor growth. In MMCs transfected with 2'-O-methyl antisense oligonucleotides to let-7 miRNA, EphrinA1 activation failed to inhibit the proliferative response and tumor growth. In mismatch antisense oligonucleotide-treated MMCs, the proliferation and tumor growth were comparable to untreated proliferating cells. Furthermore, the transfection of MMCs with let-7a miRNA precursor inhibited RAS expression and attenuated MMC tumor growth. Our data revealed that EphrinA1 signaling induces let-7 miRNA expression and attenuates MM tumor growth by targeting RAS proto-oncogene in MMCs.
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Fracalossi ACC, Comparini L, Funabashi K, Godoy C, Iwamura ESM, Nascimento FD, Nader HB, Oshima CTF, Ribeiro DA. Ras gene mutation is not related to tumour invasion during rat tongue carcinogenesis induced by 4-nitroquinoline 1-oxide. J Oral Pathol Med 2011; 40:325-33. [DOI: 10.1111/j.1600-0714.2010.00987.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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