1
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Zhao S, Mekbib KY, van der Ent MA, Allington G, Prendergast A, Chau JE, Smith H, Shohfi J, Ocken J, Duran D, Furey CG, Hao LT, Duy PQ, Reeves BC, Zhang J, Nelson-Williams C, Chen D, Li B, Nottoli T, Bai S, Rolle M, Zeng X, Dong W, Fu PY, Wang YC, Mane S, Piwowarczyk P, Fehnel KP, See AP, Iskandar BJ, Aagaard-Kienitz B, Moyer QJ, Dennis E, Kiziltug E, Kundishora AJ, DeSpenza T, Greenberg ABW, Kidanemariam SM, Hale AT, Johnston JM, Jackson EM, Storm PB, Lang SS, Butler WE, Carter BS, Chapman P, Stapleton CJ, Patel AB, Rodesch G, Smajda S, Berenstein A, Barak T, Erson-Omay EZ, Zhao H, Moreno-De-Luca A, Proctor MR, Smith ER, Orbach DB, Alper SL, Nicoli S, Boggon TJ, Lifton RP, Gunel M, King PD, Jin SC, Kahle KT. Mutation of key signaling regulators of cerebrovascular development in vein of Galen malformations. Nat Commun 2023; 14:7452. [PMID: 37978175 PMCID: PMC10656524 DOI: 10.1038/s41467-023-43062-z] [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: 11/07/2022] [Accepted: 10/30/2023] [Indexed: 11/19/2023] Open
Abstract
To elucidate the pathogenesis of vein of Galen malformations (VOGMs), the most common and most severe of congenital brain arteriovenous malformations, we performed an integrated analysis of 310 VOGM proband-family exomes and 336,326 human cerebrovasculature single-cell transcriptomes. We found the Ras suppressor p120 RasGAP (RASA1) harbored a genome-wide significant burden of loss-of-function de novo variants (2042.5-fold, p = 4.79 x 10-7). Rare, damaging transmitted variants were enriched in Ephrin receptor-B4 (EPHB4) (17.5-fold, p = 1.22 x 10-5), which cooperates with p120 RasGAP to regulate vascular development. Additional probands had damaging variants in ACVRL1, NOTCH1, ITGB1, and PTPN11. ACVRL1 variants were also identified in a multi-generational VOGM pedigree. Integrative genomic analysis defined developing endothelial cells as a likely spatio-temporal locus of VOGM pathophysiology. Mice expressing a VOGM-specific EPHB4 kinase-domain missense variant (Phe867Leu) exhibited disrupted developmental angiogenesis and impaired hierarchical development of arterial-capillary-venous networks, but only in the presence of a "second-hit" allele. These results illuminate human arterio-venous development and VOGM pathobiology and have implications for patients and their families.
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Affiliation(s)
- Shujuan Zhao
- Department of Genetics, Washington University School of Medicine, St. Louis, MO, USA
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Kedous Y Mekbib
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | - Martijn A van der Ent
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Garrett Allington
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
| | - Andrew Prendergast
- Yale Zebrafish Research Core, Yale School of Medicine, New Haven, CT, USA
| | - Jocelyn E Chau
- Department of Molecular Biophysics and Biochemistry, Yale School of Medicine, New Haven, CT, USA
| | - Hannah Smith
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | - John Shohfi
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | - Jack Ocken
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | - Daniel Duran
- Department of Neurosurgery, University of Mississippi Medical Center, Jackson, MS, USA
| | - Charuta G Furey
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
- Department of Neurosurgery, Barrow Neurological Institute, Phoenix, AZ, USA
- Ivy Brain Tumor Center, Department of Translational Neuroscience, Barrow Neurological Institute, Phoenix, AZ, USA
| | - Le Thi Hao
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Phan Q Duy
- Department of Neurosurgery, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Benjamin C Reeves
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | - Junhui Zhang
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA
| | | | - Di Chen
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Boyang Li
- Department of Biostatistics, Yale School of Public Health, New Haven, CT, USA
| | - Timothy Nottoli
- Yale Genome Editing Center, Department of Comparative Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Suxia Bai
- Yale Genome Editing Center, Department of Comparative Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Myron Rolle
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Xue Zeng
- Department of Molecular Biophysics and Biochemistry, Yale School of Medicine, New Haven, CT, USA
- Laboratory of Human Genetics and Genomics, The Rockefeller University, New York, NY, USA
| | - Weilai Dong
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA
- Laboratory of Human Genetics and Genomics, The Rockefeller University, New York, NY, USA
| | - Po-Ying Fu
- Department of Genetics, Washington University School of Medicine, St. Louis, MO, USA
| | - Yung-Chun Wang
- Department of Genetics, Washington University School of Medicine, St. Louis, MO, USA
| | - Shrikant Mane
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA
| | - Paulina Piwowarczyk
- Department of Neurosurgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Katie Pricola Fehnel
- Department of Neurosurgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Alfred Pokmeng See
- Department of Neurosurgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Bermans J Iskandar
- Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Beverly Aagaard-Kienitz
- Department of Neurological Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA
| | - Quentin J Moyer
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Evan Dennis
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Emre Kiziltug
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Adam J Kundishora
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | - Tyrone DeSpenza
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | - Ana B W Greenberg
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | | | - Andrew T Hale
- Department of Neurosurgery, University of Alabama School of Medicine, Birmingham, AL, USA
| | - James M Johnston
- Department of Neurosurgery, University of Alabama School of Medicine, Birmingham, AL, USA
| | - Eric M Jackson
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Phillip B Storm
- Department of Neurosurgery, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
- Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Shih-Shan Lang
- Department of Neurosurgery, Hospital of the University of Pennsylvania, Philadelphia, PA, USA
- Division of Neurosurgery, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - William E Butler
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Bob S Carter
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Paul Chapman
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Christopher J Stapleton
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Aman B Patel
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Georges Rodesch
- Service de Neuroradiologie Diagnostique et Thérapeutique, Hôpital Foch, Suresnes, France
- Department of Interventional Neuroradiology, Hôpital Fondation A. de Rothschild, Paris, France
| | - Stanislas Smajda
- Department of Interventional Neuroradiology, Hôpital Fondation A. de Rothschild, Paris, France
| | - Alejandro Berenstein
- Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Tanyeri Barak
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | | | - Hongyu Zhao
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA
- Department of Biostatistics, Yale School of Public Health, New Haven, CT, USA
| | - Andres Moreno-De-Luca
- Department of Radiology, Autism & Developmental Medicine Institute, Genomic Medicine Institute, Geisinger, Danville, PA, USA
| | - Mark R Proctor
- Department of Neurosurgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Edward R Smith
- Department of Neurosurgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Darren B Orbach
- Department of Neurosurgery, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Department of Neurointerventional Radiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Seth L Alper
- Division of Nephrology and Center for Vascular Biology Research, Beth Israel Deaconess Medical Center, and Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Stefania Nicoli
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, USA
- Yale Cardiovascular Research Center, Department of Internal Medicine, Section of Cardiology, Yale School of Medicine, New Haven, CT, USA
| | - Titus J Boggon
- Department of Molecular Biophysics and Biochemistry, Yale School of Medicine, New Haven, CT, USA
- Department of Pharmacology, Yale School of Medicine, New Haven, CT, USA
| | - Richard P Lifton
- Laboratory of Human Genetics and Genomics, The Rockefeller University, New York, NY, USA
| | - Murat Gunel
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA
| | - Philip D King
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Sheng Chih Jin
- Department of Genetics, Washington University School of Medicine, St. Louis, MO, USA.
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, USA.
| | - Kristopher T Kahle
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
- Department of Neurosurgery, Yale School of Medicine, New Haven, CT, USA.
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, US.
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.
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Zhao S, Mekbib KY, van der Ent MA, Allington G, Prendergast A, Chau JE, Smith H, Shohfi J, Ocken J, Duran D, Furey CG, Le HT, Duy PQ, Reeves BC, Zhang J, Nelson-Williams C, Chen D, Li B, Nottoli T, Bai S, Rolle M, Zeng X, Dong W, Fu PY, Wang YC, Mane S, Piwowarczyk P, Fehnel KP, See AP, Iskandar BJ, Aagaard-Kienitz B, Kundishora AJ, DeSpenza T, Greenberg ABW, Kidanemariam SM, Hale AT, Johnston JM, Jackson EM, Storm PB, Lang SS, Butler WE, Carter BS, Chapman P, Stapleton CJ, Patel AB, Rodesch G, Smajda S, Berenstein A, Barak T, Erson-Omay EZ, Zhao H, Moreno-De-Luca A, Proctor MR, Smith ER, Orbach DB, Alper SL, Nicoli S, Boggon TJ, Lifton RP, Gunel M, King PD, Jin SC, Kahle KT. Genetic dysregulation of an endothelial Ras signaling network in vein of Galen malformations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.18.532837. [PMID: 36993588 PMCID: PMC10055230 DOI: 10.1101/2023.03.18.532837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
To elucidate the pathogenesis of vein of Galen malformations (VOGMs), the most common and severe congenital brain arteriovenous malformation, we performed an integrated analysis of 310 VOGM proband-family exomes and 336,326 human cerebrovasculature single-cell transcriptomes. We found the Ras suppressor p120 RasGAP ( RASA1 ) harbored a genome-wide significant burden of loss-of-function de novo variants (p=4.79×10 -7 ). Rare, damaging transmitted variants were enriched in Ephrin receptor-B4 ( EPHB4 ) (p=1.22×10 -5 ), which cooperates with p120 RasGAP to limit Ras activation. Other probands had pathogenic variants in ACVRL1 , NOTCH1 , ITGB1 , and PTPN11 . ACVRL1 variants were also identified in a multi-generational VOGM pedigree. Integrative genomics defined developing endothelial cells as a key spatio-temporal locus of VOGM pathophysiology. Mice expressing a VOGM-specific EPHB4 kinase-domain missense variant exhibited constitutive endothelial Ras/ERK/MAPK activation and impaired hierarchical development of angiogenesis-regulated arterial-capillary-venous networks, but only when carrying a "second-hit" allele. These results illuminate human arterio-venous development and VOGM pathobiology and have clinical implications.
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Stiegler AL, Vish KJ, Boggon TJ. Tandem engagement of phosphotyrosines by the dual SH2 domains of p120RasGAP. Structure 2022; 30:1603-1614.e5. [PMID: 36417908 PMCID: PMC9722645 DOI: 10.1016/j.str.2022.10.009] [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: 06/27/2022] [Revised: 09/22/2022] [Accepted: 10/27/2022] [Indexed: 11/23/2022]
Abstract
p120RasGAP is a multidomain GTPase-activating protein for Ras. The presence of two Src homology 2 domains in an SH2-SH3-SH2 module raises the possibility that p120RasGAP simultaneously binds dual phosphotyrosine residues in target proteins. One known binding partner with two proximal phosphotyrosines is p190RhoGAP, a GTPase-activating protein for Rho GTPases. Here, we present the crystal structure of the p120RasGAP SH2-SH3-SH2 module bound to a doubly tyrosine-phosphorylated p190RhoGAP peptide, revealing simultaneous phosphotyrosine recognition by the SH2 domains. The compact arrangement places the SH2 domains in close proximity resembling an SH2 domain tandem and exposed SH3 domain. Affinity measurements support synergistic binding, while solution scattering reveals that dual phosphotyrosine binding induces compaction of this region. Our studies reflect a binding mode that limits conformational flexibility within the SH2-SH3-SH2 cassette and relies on the spacing and sequence surrounding the two phosphotyrosines, potentially representing a selectivity mechanism for downstream signaling events.
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Affiliation(s)
- Amy L Stiegler
- Department of Pharmacology, Yale University, New Haven, CT, USA
| | - Kimberly J Vish
- Department of Pharmacology, Yale University, New Haven, CT, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Titus J Boggon
- Department of Pharmacology, Yale University, New Haven, CT, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA; Yale Cancer Center, Yale University, New Haven, CT, USA.
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4
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Abstract
In this review, I provide a brief history of the discovery of RAS and the GAPs and GEFs that regulate its activity from a personal perspective. Much of this history has been driven by technological breakthroughs that occurred concurrently, such as molecular cloning, cDNA expression to analyze RAS proteins and their structures, and application of PCR to detect mutations. I discuss the RAS superfamily and RAS proteins as therapeutic targets, including recent advances in developing RAS inhibitors. I also describe the role of the RAS Initiative at Frederick National Laboratory for Cancer Research in advancing development of RAS inhibitors and providing new insights into signaling complexes and interaction of RAS proteins with the plasma membrane.
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Affiliation(s)
- Frank McCormick
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, United States; Frederick National Laboratory for Cancer Research, Frederick, MD, United States.
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5
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Primikiris P, Hadjigeorgiou G, Tsamopoulou M, Biondi A, Iosif C. Review on the current treatment status of vein of Galen malformations and future directions in research and treatment. Expert Rev Med Devices 2021; 18:933-954. [PMID: 34424109 DOI: 10.1080/17434440.2021.1970527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Vein of Galen malformations (VOGMs) represent a rare pathologic entity with often catastrophic natural history. The advances in endovascular treatment in recent years have allowed for a paradigm shift in the treatment and outcome of these high-flow shunts, even though their pathogenetic mechanisms and evolution remain in part obscure. AREAS COVERED The overall management of VOGMs requires a tailored case-to-case approach, starting with in utero detection and reserving endovascular treatment for indicated cases. Lately, the advances in translational research with whole-genome sequencing and the coupling with cellular-level hemodynamics attempt to shed more light in the pathogenesis and evolution of these lesions. At the same time the advances in endovascular techniques allow for more safety and tailored technical strategy planning. Furthermore, the advances in MRI techniques allow a better understanding of their vascular anatomy. In view of these recent advances and by performing a PUBMED literature review of the last 15 years, we attempt a review of the evolutions in the imaging, management, endovascular treatment and understanding of underlying mechanisms for VOGMs. EXPERT OPINION The progress in the fields detailed in this review appears very promising in better understanding VOGMs and expanding the available therapeutic arsenal.
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Affiliation(s)
- Panagiotis Primikiris
- Department of Interventional Neuroradiology, Jean Minjoz University Hospital, Besancon, France
| | | | - Maria Tsamopoulou
- School of Medicine, National Kapodistrian University of Athens, Greece
| | - Alessandra Biondi
- Department of Interventional Neuroradiology, Jean Minjoz University Hospital, Besancon, France
| | - Christina Iosif
- School of Medicine, European University of Cyprus, Nicosia, Cyprus.,Department of Interventional Neuroradiology, Henry Dunant Hospital, Athens, Greece
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Gasper R, Wittinghofer F. The Ras switch in structural and historical perspective. Biol Chem 2020; 401:143-163. [PMID: 31600136 DOI: 10.1515/hsz-2019-0330] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 09/23/2019] [Indexed: 12/22/2022]
Abstract
Since its discovery as an oncogene more than 40 years ago, Ras has been and still is in the focus of many academic and pharmaceutical labs around the world. A huge amount of work has accumulated on its biology. However, many questions about the role of the different Ras isoforms in health and disease still exist and a full understanding will require more intensive work in the future. Here we try to survey some of the structural findings in a historical perspective and how it has influenced our understanding of structure-function and mechanistic relationships of Ras and its interactions. The structures show that Ras is a stable molecular machine that uses the dynamics of its switch regions for the interaction with all regulators and effectors. This conformational flexibility has been used to create small molecule drug candidates against this important oncoprotein.
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Affiliation(s)
- Raphael Gasper
- Max-Planck-Institut für molekulare Physiologie, Otto-Hahn-Str. 11, D-44227 Dortmund, Germany
| | - Fred Wittinghofer
- Max-Planck-Institut für molekulare Physiologie, Otto-Hahn-Str. 11, D-44227 Dortmund, Germany
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7
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Jaber Chehayeb R, Wang J, Stiegler AL, Boggon TJ. The GTPase-activating protein p120RasGAP has an evolutionarily conserved "FLVR-unique" SH2 domain. J Biol Chem 2020; 295:10511-10521. [PMID: 32540970 PMCID: PMC7397115 DOI: 10.1074/jbc.ra120.013976] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/09/2020] [Indexed: 01/07/2023] Open
Abstract
The Src homology 2 (SH2) domain has a highly conserved architecture that recognizes linear phosphotyrosine motifs and is present in a wide range of signaling pathways across different evolutionary taxa. A hallmark of SH2 domains is the arginine residue in the conserved FLVR motif that forms a direct salt bridge with bound phosphotyrosine. Here, we solve the X-ray crystal structures of the C-terminal SH2 domain of p120RasGAP (RASA1) in its apo and peptide-bound form. We find that the arginine residue in the FLVR motif does not directly contact pTyr1087 of a bound phosphopeptide derived from p190RhoGAP; rather, it makes an intramolecular salt bridge to an aspartic acid. Unexpectedly, coordination of phosphotyrosine is achieved by a modified binding pocket that appears early in evolution. Using isothermal titration calorimetry, we find that substitution of the FLVR arginine R377A does not cause a significant loss of phosphopeptide binding, but rather a tandem substitution of R398A (SH2 position βD4) and K400A (SH2 position βD6) is required to disrupt the binding. These results indicate a hitherto unrecognized diversity in SH2 domain interactions with phosphotyrosine and classify the C-terminal SH2 domain of p120RasGAP as "FLVR-unique."
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Affiliation(s)
- Rachel Jaber Chehayeb
- Yale College, New Haven, Connecticut, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Jessica Wang
- Yale College, New Haven, Connecticut, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Amy L Stiegler
- Department of Pharmacology, Yale University, New Haven, Connecticut, USA
| | - Titus J Boggon
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
- Department of Pharmacology, Yale University, New Haven, Connecticut, USA
- Yale Cancer Center, Yale University, New Haven, Connecticut, USA
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8
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Harrell Stewart DR, Clark GJ. Pumping the brakes on RAS - negative regulators and death effectors of RAS. J Cell Sci 2020; 133:133/3/jcs238865. [PMID: 32041893 DOI: 10.1242/jcs.238865] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Mutations that activate the RAS oncoproteins are common in cancer. However, aberrant upregulation of RAS activity often occurs in the absence of activating mutations in the RAS genes due to defects in RAS regulators. It is now clear that loss of function of Ras GTPase-activating proteins (RasGAPs) is common in tumors, and germline mutations in certain RasGAP genes are responsible for some clinical syndromes. Although regulation of RAS is central to their activity, RasGAPs exhibit great diversity in their binding partners and therefore affect signaling by multiple mechanisms that are independent of RAS. The RASSF family of tumor suppressors are essential to RAS-induced apoptosis and senescence, and constitute a barrier to RAS-mediated transformation. Suppression of RASSF protein expression can also promote the development of excessive RAS signaling by uncoupling RAS from growth inhibitory pathways. Here, we will examine how these effectors of RAS contribute to tumor suppression, through both RAS-dependent and RAS-independent mechanisms.
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Affiliation(s)
- Desmond R Harrell Stewart
- Department of Pharmacology & Toxicology, University of Louisville School of Medicine, Louisville, KY 40222, USA
| | - Geoffrey J Clark
- Department of Pharmacology & Toxicology, University of Louisville School of Medicine, Louisville, KY 40222, USA
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9
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Jaber Chehayeb R, Boggon TJ. SH2 Domain Binding: Diverse FLVRs of Partnership. Front Endocrinol (Lausanne) 2020; 11:575220. [PMID: 33042028 PMCID: PMC7530234 DOI: 10.3389/fendo.2020.575220] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/12/2020] [Indexed: 11/27/2022] Open
Abstract
The Src homology 2 (SH2) domain has a special role as one of the cornerstone examples of a "modular" domain. The interactions of this domain are very well-conserved, and have long been described as a bidentate, or "two-pronged plug" interaction between the domain and a phosphotyrosine (pTyr) peptide. Recent work has, however, highlighted unusual features of the SH2 domain that illustrate a greater diversity than was previously appreciated. In this review we discuss some of the novel and unusual characteristics across the SH2 family, including unusual peptide binding pockets, multiple pTyr recognition sites, recognition sites for unphosphorylated peptides, and recently identified variability in the conserved FLVR motif.
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Affiliation(s)
- Rachel Jaber Chehayeb
- Yale College, New Haven, CT, United States
- Department of Molecular Biophysics and Biochemistry, New Haven, CT, United States
| | - Titus J. Boggon
- Department of Molecular Biophysics and Biochemistry, New Haven, CT, United States
- Department of Pharmacology, New Haven, CT, United States
- Yale Cancer Center, Yale University, New Haven, CT, United States
- *Correspondence: Titus J. Boggon
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10
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Scheffzek K, Shivalingaiah G. Ras-Specific GTPase-Activating Proteins-Structures, Mechanisms, and Interactions. Cold Spring Harb Perspect Med 2019; 9:cshperspect.a031500. [PMID: 30104198 DOI: 10.1101/cshperspect.a031500] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Ras-specific GTPase-activating proteins (RasGAPs) down-regulate the biological activity of Ras proteins by accelerating their intrinsic rate of GTP hydrolysis, basically by a transition state stabilizing mechanism. Oncogenic Ras is commonly not sensitive to RasGAPs caused by interference of mutants with the electronic or steric requirements of the transition state, resulting in up-regulation of activated Ras in respective cells. RasGAPs are modular proteins containing a helical catalytic RasGAP module surrounded by smaller domains that are frequently involved in the subcellular localization or contributing to regulatory features of their host proteins. In this review, we summarize current knowledge about RasGAP structure, mechanism, regulation, and dual-substrate specificity and discuss in some detail neurofibromin, one of the most important negative Ras regulators in cellular growth control and neuronal function.
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Affiliation(s)
- Klaus Scheffzek
- Division of Biological Chemistry (Biocenter), Medical University of Innsbruck, A-6020 Innsbruck, Austria
| | - Giridhar Shivalingaiah
- Division of Biological Chemistry (Biocenter), Medical University of Innsbruck, A-6020 Innsbruck, Austria
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11
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Zeng X, Hunt A, Jin SC, Duran D, Gaillard J, Kahle KT. EphrinB2-EphB4-RASA1 Signaling in Human Cerebrovascular Development and Disease. Trends Mol Med 2019; 25:265-286. [PMID: 30819650 DOI: 10.1016/j.molmed.2019.01.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 01/17/2019] [Accepted: 01/29/2019] [Indexed: 12/13/2022]
Abstract
Recent whole exome sequencing studies in humans have provided novel insight into the importance of the ephrinB2-EphB4-RASA1 signaling axis in cerebrovascular development, corroborating and extending previous work in model systems. Here, we aim to review the human cerebrovascular phenotypes associated with ephrinB2-EphB4-RASA1 mutations, including those recently discovered in Vein of Galen malformation: the most common and severe brain arteriovenous malformation in neonates. We will also discuss emerging paradigms of the molecular and cellular pathophysiology of disease-causing ephrinB2-EphB4-RASA1 mutations, including the potential role of somatic mosaicism. These observations have potential diagnostic and therapeutic implications for patients with rare congenital cerebrovascular diseases and their families.
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Affiliation(s)
- Xue Zeng
- Department of Genetics, Yale School of Medicine, New Haven CT, USA; Laboratory of Human Genetics and Genomics, The Rockefeller University, New York, NY, USA
| | - Ava Hunt
- Department of Neurosurgery, Yale School of Medicine, New Haven CT, USA
| | - Sheng Chih Jin
- Laboratory of Human Genetics and Genomics, The Rockefeller University, New York, NY, USA
| | - Daniel Duran
- Department of Neurosurgery, Yale School of Medicine, New Haven CT, USA
| | - Jonathan Gaillard
- Department of Neurosurgery, Yale School of Medicine, New Haven CT, USA
| | - Kristopher T Kahle
- Department of Neurosurgery, Yale School of Medicine, New Haven CT, USA; Department of Pediatrics, Yale School of Medicine, New Haven CT, USA; Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven CT, USA.
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12
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Shin Y, Kim YW, Kim H, Shin N, Kim TS, Kwon TK, Choi JH, Chang JS. RASAL3 preferentially stimulates GTP hydrolysis of the Rho family small GTPase Rac2. Biomed Rep 2018; 9:241-246. [PMID: 30271600 DOI: 10.3892/br.2018.1119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 06/28/2018] [Indexed: 11/05/2022] Open
Abstract
Members of the Ras superfamily of small G-proteins serve as molecular switches of intracellular signaling pathways. Rac2 is a Rho subfamily GTPase switch that is specifically expressed in hematopoietic cells and regulates AKT activation in cell signaling. Ras activating protein-like 3 (RASAL3) is the recently identified Ras GTPase activating protein (GAP) that is also specifically expressed in hematopoietic cells and stimulates p21ras GTPase activity. The restricted expression of both Rac2 and RASAL3 suggests that they may serve critical roles in hematopoietic cell signaling. Here in the present study demonstrates that the catalytic domain of RASAL3 may also be able to interact with Rac2 and stimulate its GTPase activity in vitro. By contrast, p50 rhoGAP molecules did not markedly affect Rac2 GTPase activity, but did accelerate the activity of other Rho GTPases, including Rac1, RhoA and Cdc42. Collectively, the present results indicate, seemingly for the first time, that GAP activity for Rac2 is regulated by the RasGAP family protein, RASAL3.
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Affiliation(s)
- Yoonjae Shin
- Department of Life Science, College of Science and Technology, Daejin University, Pocheon-Si, Gyeonggi-Do 11159, South Korea
| | - Yong Woo Kim
- Department of Life Science, College of Science and Technology, Daejin University, Pocheon-Si, Gyeonggi-Do 11159, South Korea
| | - Hyemin Kim
- Department of Life Science, College of Science and Technology, Daejin University, Pocheon-Si, Gyeonggi-Do 11159, South Korea
| | - Nakyoung Shin
- Department of Life Science, College of Science and Technology, Daejin University, Pocheon-Si, Gyeonggi-Do 11159, South Korea
| | - Tae Sung Kim
- Department of Life Science, College of Science and Technology, Daejin University, Pocheon-Si, Gyeonggi-Do 11159, South Korea
| | - Taeg Kyu Kwon
- Department of Immunology and Physiology, School of Medicine, Keimyung University, Daegu 42601, South Korea
| | - Jang Hyun Choi
- Department of Biological Sciences, Division of Life Sciences, Ulsan National Institute of Science and Technology, Ulsan 44919, South Korea
| | - Jong-Soo Chang
- Department of Life Science, College of Science and Technology, Daejin University, Pocheon-Si, Gyeonggi-Do 11159, South Korea
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Choi Y, Kwon CH, Lee SJ, Park J, Shin JY, Park DY. Integrative analysis of oncogenic fusion genes and their functional impact in colorectal cancer. Br J Cancer 2018; 119:230-240. [PMID: 29955133 PMCID: PMC6048111 DOI: 10.1038/s41416-018-0153-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2018] [Revised: 05/22/2018] [Accepted: 05/29/2018] [Indexed: 12/21/2022] Open
Abstract
Background Fusion genes are good candidates of molecular targets for cancer therapy. However, there is insufficient research on the clinical implications and functional characteristics of fusion genes in colorectal cancer (CRC). Methods In this study, we analysed RNA sequencing data of CRC patients (147 tumour and 47 matched normal tissues) to identify oncogenic fusion genes and evaluated their role in CRC. Results We validated 24 fusion genes, including novel fusions, by three algorithms and Sanger sequencing. Fusions from most patients were mutually exclusive CRC oncogenes and included tumour suppressor gene mutations. Eleven fusion genes from 13 patients (8.8%) were determined as oncogenic fusion genes by analysing their gene expression and function. To investigate their oncogenic impact, we performed proliferation and migration assays of CRC cell lines expressing fusion genes of GTF3A-CDK8, NAGLU- IKZF3, RNF121- FOLR2, and STRN-ALK. Overexpression of these fusion genes increased cell proliferation except GTF3A-CDK8. In addition, overexpression of NAGLU-IKZF3 enhanced migration of CRC cells. We demonstrated that NAGLU-IKZF3, RNF121-FOLR2, and STRN-ALK had tumourigenic effects in CRC. Conclusion In summary, we identified and characterised oncogenic fusion genes and their function in CRC, and implicated NAGLU-IKZF3 and RNF121-FOLR2 as novel molecular targets for personalised medicine development.
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Affiliation(s)
- Yuri Choi
- Department of Pathology, Pusan National University School of Medicine, and Biomedical Research Institute, Pusan National University Hospital, Gudeok-ro 179, Seo-Gu, Busan, 49241, Republic of Korea
| | - Chae Hwa Kwon
- Department of Pathology, Pusan National University School of Medicine, and Biomedical Research Institute, Pusan National University Hospital, Gudeok-ro 179, Seo-Gu, Busan, 49241, Republic of Korea
| | - Seon Jin Lee
- Department of Pathology, Pusan National University School of Medicine, and Biomedical Research Institute, Pusan National University Hospital, Gudeok-ro 179, Seo-Gu, Busan, 49241, Republic of Korea
| | - Joonghoon Park
- Graduate School of International Agricultural Technology and Institute of Green-Bio Science and Technology, Seoul National University, Pyeongchang-gun, Gangwon-do, 232-916, Republic of Korea
| | - Jong-Yeon Shin
- Genomic Medicine Institute (GMI), Medical Research Center, Seoul National University, Seoul, 159-781, Republic of Korea
| | - Do Youn Park
- Department of Pathology, Pusan National University School of Medicine, and Biomedical Research Institute, Pusan National University Hospital, Gudeok-ro 179, Seo-Gu, Busan, 49241, Republic of Korea.
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14
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Kumar R, Khandelwal N, Thachamvally R, Tripathi BN, Barua S, Kashyap SK, Maherchandani S, Kumar N. Role of MAPK/MNK1 signaling in virus replication. Virus Res 2018; 253:48-61. [PMID: 29864503 PMCID: PMC7114592 DOI: 10.1016/j.virusres.2018.05.028] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 04/16/2018] [Accepted: 05/31/2018] [Indexed: 12/23/2022]
Abstract
Viruses are known to exploit cellular signaling pathways. MAPK is a major cell signaling pathway activated by diverse group of viruses. MNK1 regulates both cap-dependent and IRES-mediated mRNA translation. This review discuss the role of MAPK, particularly the role of MNK1 in virus replication.
Viruses are obligate intracellular parasites; they heavily depend on the host cell machinery to effectively replicate and produce new progeny virus particles. Following viral infection, diverse cell signaling pathways are initiated by the cells, with the major goal of establishing an antiviral state. However, viruses have been shown to exploit cellular signaling pathways for their own effective replication. Genome-wide siRNA screens have also identified numerous host factors that either support (proviral) or inhibit (antiviral) virus replication. Some of the host factors might be dispensable for the host but may be critical for virus replication; therefore such cellular factors may serve as targets for development of antiviral therapeutics. Mitogen activated protein kinase (MAPK) is a major cell signaling pathway that is known to be activated by diverse group of viruses. MAPK interacting kinase 1 (MNK1) has been shown to regulate both cap-dependent and internal ribosomal entry sites (IRES)-mediated mRNA translation. In this review we have discuss the role of MAPK in virus replication, particularly the role of MNK1 in replication and translation of viral genome.
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Affiliation(s)
- Ram Kumar
- Virology Laboratory, National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana 125001, India; Department of Veterinary Microbiology and Biotechnology, Rajasthan University of Veterinary and Animal Sciences, Bikaner, Rajasthan 334001, India
| | - Nitin Khandelwal
- Virology Laboratory, National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana 125001, India
| | - Riyesh Thachamvally
- Virology Laboratory, National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana 125001, India
| | - Bhupendra Nath Tripathi
- Virology Laboratory, National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana 125001, India
| | - Sanjay Barua
- Virology Laboratory, National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana 125001, India
| | - Sudhir Kumar Kashyap
- Department of Veterinary Microbiology and Biotechnology, Rajasthan University of Veterinary and Animal Sciences, Bikaner, Rajasthan 334001, India
| | - Sunil Maherchandani
- Department of Veterinary Microbiology and Biotechnology, Rajasthan University of Veterinary and Animal Sciences, Bikaner, Rajasthan 334001, India
| | - Naveen Kumar
- Virology Laboratory, National Centre for Veterinary Type Cultures, ICAR-National Research Centre on Equines, Hisar, Haryana 125001, India.
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15
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Duran D, Karschnia P, Gaillard JR, Karimy JK, Youngblood MW, DiLuna ML, Matouk CC, Aagaard-Kienitz B, Smith ER, Orbach DB, Rodesch G, Berenstein A, Gunel M, Kahle KT. Human genetics and molecular mechanisms of vein of Galen malformation. J Neurosurg Pediatr 2018; 21:367-374. [PMID: 29350590 DOI: 10.3171/2017.9.peds17365] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Vein of Galen malformations (VOGMs) are rare developmental cerebrovascular lesions characterized by fistulas between the choroidal circulation and the median prosencephalic vein. Although the treatment of VOGMs has greatly benefited from advances in endovascular therapy, including technical innovation in interventional neuroradiology, many patients are recalcitrant to procedural intervention or lack accessibility to specialized care centers, highlighting the need for improved screening, diagnostics, and therapeutics. A fundamental obstacle to identifying novel targets is the limited understanding of VOGM molecular pathophysiology, including its human genetics, and the lack of an adequate VOGM animal model. Herein, the known human mutations associated with VOGMs are reviewed to provide a framework for future gene discovery. Gene mutations have been identified in 2 Mendelian syndromes of which VOGM is an infrequent but associated phenotype: capillary malformation-arteriovenous malformation syndrome ( RASA1) and hereditary hemorrhagic telangiectasia ( ENG and ACVRL1). However, these mutations probably represent only a small fraction of all VOGM cases. Traditional genetic approaches have been limited in their ability to identify additional causative genes for VOGM because kindreds are rare, limited in patient number, and/or seem to have sporadic inheritance patterns, attributable in part to incomplete penetrance and phenotypic variability. The authors hypothesize that the apparent sporadic occurrence of VOGM may frequently be attributable to de novo mutation or incomplete penetrance of rare transmitted variants. Collaboration among treating physicians, patients' families, and investigators using next-generation sequencing could lead to the discovery of novel genes for VOGM. This could improve the understanding of normal vascular biology, elucidate the pathogenesis of VOGM and possibly other more common arteriovenous malformation subtypes, and pave the way for advances in the diagnosis and treatment of patients with VOGM.
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Affiliation(s)
| | | | | | | | | | | | | | - Beverly Aagaard-Kienitz
- 2Department of Neurological Surgery, University of Wisconsin, Madison, Wisconsin; Departments of
| | | | - Darren B Orbach
- 4Neurointerventional Radiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Georges Rodesch
- 5Service de Neuroradiologie Diagnostique et Thérapeutique, Hôpital Foch, Suresnes, France; and
| | - Alejandro Berenstein
- 6Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Murat Gunel
- 1Department of Neurosurgery.,7Department of Genetics.,8Centers for Mendelian Genomics and Yale Program on Neurogenetics, and
| | - Kristopher T Kahle
- 1Department of Neurosurgery.,8Centers for Mendelian Genomics and Yale Program on Neurogenetics, and.,9Department of Pediatrics and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut
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16
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Circulating MicroRNA-21 Is Involved in Lymph Node Metastasis in Cervical Cancer by Targeting RASA1. Int J Gynecol Cancer 2017; 26:810-6. [PMID: 27101583 DOI: 10.1097/igc.0000000000000694] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVE The aims of this study were to discover if increased circulating microRNA-21 (miR-21) expression in serum is associated with lymph node metastasis in patients with cervical cancer and look further into the molecular mechanism of these. Whole-blood samples from 89 patients who have been histopathologically confirmed as having cervical cancer and 20 control subjects were collected, and then the association between lymph node metastasis and the level of circulating miR-21 was compared. Then cervical cancer cell lines HeLa (HPV-18 DNA, E6/E7RNA) and HT-3 (HPV DNA, E6/E7RNA) were used to confirm the interaction between miR-21 and RASA1. The role of RASA1 in cervical cancer cell migration was also studied in HeLa. Increased circulating miR-21 expression in serum is associated with lymph node metastasis in patients with cervical cancer. MicroRNA-21 reduces RASA1 expression in cervical cancer cell lines and promotes cervical cancer cell migration via RASA1. Furthermore, Ras-induced epithelial-mesenchymal transition contributes to miR-21/RASA1 axis promoting cervical cancer cell migration. Circulating miR-21 in serum could be a promising biomarker in auxiliary diagnosis of lymph node metastasis in cervical cancer, and inhibition of miR-21/RASA1 axis could be a possible strategy to restrain migration of cervical cancer.
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Abstract
Cells respond to changes in their environment, to developmental cues, and to pathogen aggression through the action of a complex network of proteins. These networks can be decomposed into a multitude of signaling pathways that relay signals from the microenvironment to the cellular components involved in eliciting a specific response. Perturbations in these signaling processes are at the root of multiple pathologies, the most notable of these being cancer. The study of receptor tyrosine kinase (RTK) signaling led to the first description of a mechanism whereby an extracellular signal is transmitted to the nucleus to induce a transcriptional response. Genetic studies conducted in drosophila and nematodes have provided key elements to this puzzle. Here, we briefly discuss the somewhat lesser known contribution of these multicellular organisms to our understanding of what has come to be known as the prototype of signaling pathways. We also discuss the ostensibly much larger network of regulators that has emerged from recent functional genomic investigations of RTK/RAS/ERK signaling.
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Affiliation(s)
- Dariel Ashton-Beaucage
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montreal, QC, Canada, H3C 3J7
| | - Marc Therrien
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montreal, QC, Canada, H3C 3J7.
- Département de Pathologie et de Biologie Cellulaire, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montreal, QC, Canada, H3C 3J7.
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18
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Testing for Ancient Selection Using Cross-population Allele Frequency Differentiation. Genetics 2015; 202:733-50. [PMID: 26596347 DOI: 10.1534/genetics.115.178095] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Accepted: 11/18/2015] [Indexed: 12/18/2022] Open
Abstract
A powerful way to detect selection in a population is by modeling local allele frequency changes in a particular region of the genome under scenarios of selection and neutrality and finding which model is most compatible with the data. A previous method based on a cross-population composite likelihood ratio (XP-CLR) uses an outgroup population to detect departures from neutrality that could be compatible with hard or soft sweeps, at linked sites near a beneficial allele. However, this method is most sensitive to recent selection and may miss selective events that happened a long time ago. To overcome this, we developed an extension of XP-CLR that jointly models the behavior of a selected allele in a three-population tree. Our method - called "3-population composite likelihood ratio" (3P-CLR) - outperforms XP-CLR when testing for selection that occurred before two populations split from each other and can distinguish between those events and events that occurred specifically in each of the populations after the split. We applied our new test to population genomic data from the 1000 Genomes Project, to search for selective sweeps that occurred before the split of Yoruba and Eurasians, but after their split from Neanderthals, and that could have led to the spread of modern-human-specific phenotypes. We also searched for sweep events that occurred in East Asians, Europeans, and the ancestors of both populations, after their split from Yoruba. In both cases, we are able to confirm a number of regions identified by previous methods and find several new candidates for selection in recent and ancient times. For some of these, we also find suggestive functional mutations that may have driven the selective events.
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19
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The discovery of modular binding domains: building blocks of cell signalling. Nat Rev Mol Cell Biol 2015; 16:691-8. [PMID: 26420231 DOI: 10.1038/nrm4068] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cell signalling - the ability of a cell to process information from the environment and change its behaviour in response - is a central property of life. Signalling depends on proteins that are assembled from a toolkit of modular domains, each of which confers a specific activity or function. The discovery of modular protein- and lipid-binding domains was a crucial turning point in understanding the logic and evolution of signalling mechanisms.
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20
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RasGAP Promotes Autophagy and Thereby Suppresses Platelet-Derived Growth Factor Receptor-Mediated Signaling Events, Cellular Responses, and Pathology. Mol Cell Biol 2015; 35:1673-85. [PMID: 25733681 DOI: 10.1128/mcb.01248-14] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 02/24/2015] [Indexed: 11/20/2022] Open
Abstract
Platelet-derived growth factors (PDGFs) and their receptors (PDGFRs) make profound contributions to both physiology and pathology. While it is widely believed that direct (PDGF-mediated) activation is the primary mode of activating PDGFRs, the discovery that they can also be activated indirectly begs the question of the relevance of the indirect mode of activating PDGFRs. In the context of a blinding eye disease, indirect activation of PDGFRα results in persistent signaling, which suppresses the level of p53 and thereby promotes viability of cells that drive pathogenesis. Under the same conditions, PDGFRβ fails to undergo indirect activation. In this paper, we report that RasGAP (GTPase-activating protein of Ras) prevented indirect activation of PDGFRβ. RasGAP, which associates with PDGFRβ but not PDGFRα, reduced the level of mitochondrion-derived reactive oxygen species, which are required for enduring activation of PDGFRs. Furthermore, preventing PDGFRβ from associating with RasGAP allowed it to signal enduringly and drive pathogenesis of a blinding eye disease. These results indicate a previously unappreciated role of RasGAP in antagonizing indirect activation of PDGFRβ, define the underlying mechanism, and raise the possibility that PDGFRβ-mediated diseases involve indirect activation of PDGFRβ.
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21
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Liu Y, Liu T, Sun Q, Niu M, Jiang Y, Pang D. Downregulation of Ras GTPase‑activating protein 1 is associated with poor survival of breast invasive ductal carcinoma patients. Oncol Rep 2014; 33:119-24. [PMID: 25394563 DOI: 10.3892/or.2014.3604] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 09/15/2014] [Indexed: 11/05/2022] Open
Abstract
Ras GTPase‑activating protein 1 (RASA1) functions to inactivate Ras‑GTPase and inhibit the mitogenic signal. Reduction or loss of RASA1 expression occurs during human cancer development and progression. This study investigated RASA1 expression in normal and breast cancer tissue specimens to determine the association with prognosis of breast cancer patients. Two sets of patient samples (45 fresh tissues and 373 paraffin‑embedded tissues) were analyzed for RASA1 expression using RT‑qPCR and immunohisto-chemistry. The results showed that the expression of RASA1 mRNA was lower in breast cancer tissues than in the corresponding normal tissues (P<0.001). Additionally, RASA1 expression was reduced in 60.6% (226/373) of breast cancer tissues. The reduced RASA1 expression was significantly associated with tumor lymph node metastasis (P=0.002), advanced TNM stages (P=0.017), estrogen receptor (ER) expression (P=0.002), Ki‑67 (P=0.009), higher histological grade (P<0.001), and triple‑negative breast cancer (P=0.041). Moreover, the reduced RASA1 expression was associated with shorter disease‑free survival (P=0.036) and overall survival (P<0.001) of breast cancer patients. RASA1 expression, together with tumor lymph‑node metastasis, TNM stage, Her‑2 expression, and triple‑negative breast cancer were independent factors in predicting survival of breast cancer patients. In conclusion, RASA1 expression is frequently reduced in breast cancer tissues, and the reduced RASA1 expression is associated with breast cancer progression and poor survival and disease‑free survival of patients.
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Affiliation(s)
- Yang Liu
- Department of Breast Surgery, The Affiliated Cancer Hospital, Harbin Medical University, Nangang, Harbin, Heilongjiang, P.R. China
| | - Tong Liu
- Department of Breast Surgery, The Affiliated Cancer Hospital, Harbin Medical University, Nangang, Harbin, Heilongjiang, P.R. China
| | - Qian Sun
- Department of Breast Surgery, The Affiliated Cancer Hospital, Harbin Medical University, Nangang, Harbin, Heilongjiang, P.R. China
| | - Ming Niu
- Department of Breast Surgery, The Affiliated Cancer Hospital, Harbin Medical University, Nangang, Harbin, Heilongjiang, P.R. China
| | - Yang Jiang
- Department of Pathology, The Affiliated Cancer Hospital, Harbin Medical University, Nangang, Harbin, Heilongjiang, P.R. China
| | - Da Pang
- Department of Breast Surgery, The Affiliated Cancer Hospital, Harbin Medical University, Nangang, Harbin, Heilongjiang, P.R. China
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22
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Cox AD, Der CJ. Ras history: The saga continues. Small GTPases 2014; 1:2-27. [PMID: 21686117 DOI: 10.4161/sgtp.1.1.12178] [Citation(s) in RCA: 506] [Impact Index Per Article: 50.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2010] [Revised: 05/17/2010] [Accepted: 05/24/2010] [Indexed: 12/24/2022] Open
Abstract
Although the roots of Ras sprouted from the rich history of retrovirus research, it was the discovery of mutationally activated RAS genes in human cancer in 1982 that stimulated an intensive research effort to understand Ras protein structure, biochemistry and biology. While the ultimate goal has been developing anti-Ras drugs for cancer treatment, discoveries from Ras have laid the foundation for three broad areas of science. First, they focused studies on the origins of cancer to the molecular level, with the subsequent discovery of genes mutated in cancer that now number in the thousands. Second, elucidation of the biochemical mechanisms by which Ras facilitates signal transduction established many of our fundamental concepts of how a normal cell orchestrates responses to extracellular cues. Third, Ras proteins are also founding members of a large superfamily of small GTPases that regulate all key cellular processes and established the versatile role of small GTP-binding proteins in biology. We highlight some of the key findings of the last 28 years.
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Affiliation(s)
- Adrienne D Cox
- Department of Radiation Oncology; Lineberger Comprehensive Cancer Center; University of North Carolina at Chapel Hill; Chapel Hill, NC USA
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23
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Bosquet JG, Marchion DC, Chon H, Lancaster JM, Chanock S. Analysis of chemotherapeutic response in ovarian cancers using publicly available high-throughput data. Cancer Res 2014; 74:3902-12. [PMID: 24848511 DOI: 10.1158/0008-5472.can-14-0186] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A third of patients with epithelial ovarian cancer (OVCA) will not respond to standard treatment. The determination of a robust signature that predicts chemoresponse could lead to the identification of molecular markers for response as well as possible clinical implementation in the future to identify patients at risk of failing therapy. This pilot study was designed to identify biologic processes affecting candidate pathways associated with chemoresponse and to create a robust gene signature for follow-up studies. After identifying common pathways associated with chemoresponse in serous OVCA in three independent gene-expression experiments, we assessed the biologic processes associated with them using The Cancer Genome Atlas (TCGA) dataset for serous OVCA. We identified differential copy-number alterations (CNA), mutations, DNA methylation, and miRNA expression between patients that responded to standard treatment and those who did not or recurred prematurely. We correlated these significant parameters with gene expression to create a signature of 422 genes associated with chemoresponse. A consensus clustering of this signature identified two differentiated clusters with unique molecular patterns: cluster 1 was significant for cellular signaling and immune response (mainly cell-mediated); and cluster 2 was significant for pathways involving DNA-damage repair and replication, cell cycle, and apoptosis. Validation through consensus clustering was performed in five independent OVCA gene-expression experiments. Genes were located in the same cluster with consistent agreement in all five studies (κ coefficient ≥ 0.6 in 4). Integrating high-throughput biologic data have created a robust molecular signature that predicts chemoresponse in OVCA.
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Affiliation(s)
- Jesus Gonzalez Bosquet
- Authors' Affiliations: Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, University of Iowa Hospitals and Clinics, Iowa City, Iowa;
| | - Douglas C Marchion
- Department of Women's Oncology, Experimental Therapeutics Program, Department of Oncologic Sciences
| | - HyeSook Chon
- Department of Women's Oncology, Gynecologic Oncology, Department of Oncologic Sciences, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida; and
| | - Johnathan M Lancaster
- Department of Women's Oncology, Gynecologic Oncology, Department of Oncologic Sciences, H. Lee Moffitt Cancer Center and Research Institute, Tampa, Florida; and
| | - Stephen Chanock
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Bethesda, Maryland
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24
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Maertens O, Cichowski K. An expanding role for RAS GTPase activating proteins (RAS GAPs) in cancer. Adv Biol Regul 2014; 55:1-14. [PMID: 24814062 DOI: 10.1016/j.jbior.2014.04.002] [Citation(s) in RCA: 119] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 04/16/2014] [Accepted: 04/16/2014] [Indexed: 10/25/2022]
Abstract
The RAS pathway is one of the most commonly deregulated pathways in human cancer. Mutations in RAS genes occur in nearly 30% of all human tumors. However in some tumor types RAS mutations are conspicuously absent or rare, despite the fact that RAS and downstream effector pathways are hyperactivated. Recently, RAS GTPase Activating Proteins (RAS GAPs) have emerged as an expanding class of tumor suppressors that, when inactivated, provide an alternative mechanism of activating RAS. RAS GAPs normally turn off RAS by catalyzing the hydrolysis of RAS-GTP. As such, the loss of a RAS GAP would be expected to promote excessive RAS activation. Indeed, this is the case for the NF1 gene, which plays an established role in a familial tumor predisposition syndrome and a variety of sporadic cancers. However, there are 13 additional RAS GAP family members in the human genome. We are only now beginning to understand why there are so many RAS GAPs, how they differentially function, and what their potential role(s) in human cancer are. This review will focus on our current understanding of RAS GAPs in human disease and will highlight important outstanding questions.
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Affiliation(s)
- Ophélia Maertens
- Genetics Division, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Karen Cichowski
- Genetics Division, Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA; Ludwig Center at Dana-Farber/Harvard Cancer Center, Boston, MA 02115, USA.
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25
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Organ SL, Hai J, Radulovich N, Marshall CB, Leung L, Sasazuki T, Shirasawa S, Zhu CQ, Navab R, Ikura M, Tsao MS. p120RasGAP is a mediator of rho pathway activation and tumorigenicity in the DLD1 colorectal cancer cell line. PLoS One 2014; 9:e86103. [PMID: 24465899 PMCID: PMC3897622 DOI: 10.1371/journal.pone.0086103] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 12/05/2013] [Indexed: 12/25/2022] Open
Abstract
KRAS is mutated in ∼40% of colorectal cancer (CRC), and there are limited effective treatments for advanced KRAS mutant CRC. Therefore, it is crucial that downstream mediators of oncogenic KRAS continue to be studied. We identified p190RhoGAP as being phosphorylated in the DLD1 CRC cell line, which expresses a heterozygous KRAS G13D allele, and not in DKO4 in which the mutant allele has been deleted by somatic recombination. We found that a ubiquitous binding partner of p190RhoGAP, p120RasGAP (RasGAP), is expressed in much lower levels in DKO4 cells compared to DLD1, and this expression is regulated by KRAS. Rescue of RasGAP expression in DKO4 rescued Rho pathway activation and partially rescued tumorigenicity in DKO4 cells, indicating that the combination of mutant KRAS and RasGAP expression is crucial to these phenotypes. We conclude that RasGAP is an important effector of mutant KRAS in CRC.
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Affiliation(s)
- Shawna L. Organ
- Princess Margaret Cancer Centre, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Josephine Hai
- Princess Margaret Cancer Centre, Toronto, Ontario, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Nikolina Radulovich
- Princess Margaret Cancer Centre, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | | | - Lisa Leung
- Princess Margaret Cancer Centre, Toronto, Ontario, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Takehiko Sasazuki
- Department of Pathology, Research Institute, International Medical Center of Japan, Tokyo, Japan
| | - Senji Shirasawa
- Department of Cell Biology, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Chang-Qi Zhu
- Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Roya Navab
- Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Mitsuhiko Ikura
- Princess Margaret Cancer Centre, Toronto, Ontario, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Ming-Sound Tsao
- Princess Margaret Cancer Centre, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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Alternative Splicing Regulation of Cancer-Related Pathways in Caenorhabditis elegans: An In Vivo Model System with a Powerful Reverse Genetics Toolbox. Int J Cell Biol 2013; 2013:636050. [PMID: 24069034 PMCID: PMC3771449 DOI: 10.1155/2013/636050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 07/29/2013] [Indexed: 11/18/2022] Open
Abstract
Alternative splicing allows for the generation of protein diversity and fine-tunes gene expression. Several model systems have been used for the in vivo study of alternative splicing. Here we review the use of the nematode Caenorhabditis elegans to study splicing regulation in vivo. Recent studies have shown that close to 25% of genes in the worm genome undergo alternative splicing. A big proportion of these events are functional, conserved, and under strict regulation either across development or other conditions. Several techniques like genome-wide RNAi screens and bichromatic reporters are available for the study of alternative splicing in worms. In this review, we focus, first, on the main studies that have been performed to dissect alternative splicing in this system and later on examples from genes that have human homologs that are implicated in cancer. The significant advancement towards understanding the regulation of alternative splicing and cancer that the C. elegans system has offered is discussed.
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King PD, Lubeck BA, Lapinski PE. Nonredundant functions for Ras GTPase-activating proteins in tissue homeostasis. Sci Signal 2013; 6:re1. [PMID: 23443682 DOI: 10.1126/scisignal.2003669] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Inactivation of the small guanosine triphosphate-binding protein Ras during receptor signal transduction is mediated by Ras guanosine triphosphatase (GTPase)-activating proteins (RasGAPs). Ten different RasGAPs have been identified and have overlapping patterns of tissue distribution. However, genetic analyses are revealing critical nonredundant functions for each RasGAP in tissue homeostasis and as regulators of disease processes in mouse and man. Here, we discuss advances in understanding the role of RasGAPs in the maintenance of tissue integrity.
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Affiliation(s)
- Philip D King
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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28
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SH3 domains: modules of protein-protein interactions. Biophys Rev 2012; 5:29-39. [PMID: 28510178 DOI: 10.1007/s12551-012-0081-z] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 05/29/2012] [Indexed: 01/01/2023] Open
Abstract
Src homology 3 (SH3) domains are involved in the regulation of important cellular pathways, such as cell proliferation, migration and cytoskeletal modifications. Recognition of polyproline and a number of noncanonical sequences by SH3 domains has been extensively studied by crystallography, nuclear magnetic resonance and other methods. High-affinity peptides that bind SH3 domains are used in drug development as candidates for anticancer treatment. This review summarizes the latest achievements in deciphering structural determinants of SH3 function.
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Kennedy RB, Ovsyannikova IG, Pankratz VS, Haralambieva IH, Vierkant RA, Jacobson RM, Poland GA. Genome-wide genetic associations with IFNγ response to smallpox vaccine. Hum Genet 2012; 131:1433-51. [PMID: 22661280 DOI: 10.1007/s00439-012-1179-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2011] [Accepted: 05/08/2012] [Indexed: 11/26/2022]
Abstract
Smallpox is a deadly and debilitating disease that killed hundreds of millions of people in the past century alone. The use of Vaccinia virus-based smallpox vaccines led to the eradication of smallpox. These vaccines are remarkably effective, inducing the characteristic pustule or "take" at the vaccine site in >97 % of recipients, and inducing a wide spectrum of long-lasting humoral and cellular immune responses. The mechanisms behind inter-individual vaccine-response variability are likely to involve host genetic variation, but have not been fully characterized. We report here the first smallpox vaccine response genome-wide association study of over 1,000 recent recipients of Dryvax(®). The data presented here focus on cellular immune responses as measured by both production of secreted IFNγ and quantitation of IFNγ secreting cells by ELISPOT assay. We identified multiple significant SNP associations in genes (RASA1, ADRA1D, TCF7L1, FAS) that are critical components of signaling pathways that directly control lymphocyte IFNγ production or cytotoxic T cell function. Similarly, we found many associations with SNPs located in genes integral to nerve cell function; findings that, given the complex interplay between the nervous and immune systems, deserve closer examination in follow-up studies.
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Affiliation(s)
- Richard B Kennedy
- Program in Translational Immunovirology and Biodefense, Mayo Clinic, Rochester, MN 55905, USA
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Ligeti E, Welti S, Scheffzek K. Inhibition and Termination of Physiological Responses by GTPase Activating Proteins. Physiol Rev 2012; 92:237-72. [DOI: 10.1152/physrev.00045.2010] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Physiological processes are strictly organized in space and time. However, in cell physiology research, more attention is given to the question of space rather than to time. To function as a signal, environmental changes must be restricted in time; they need not only be initiated but also terminated. In this review, we concentrate on the role of one specific protein family involved in biological signal termination. GTPase activating proteins (GAPs) accelerate the endogenously low GTP hydrolysis rate of monomeric guanine nucleotide-binding proteins (GNBPs), limiting thereby their prevalence in the active, GTP-bound form. We discuss cases where defective or excessive GAP activity of specific proteins causes significant alteration in the function of the nervous, endocrine, and hemopoietic systems, or contributes to development of infections and tumors. Biochemical and genetic data as well as observations from human pathology support the notion that GAPs represent vital elements in the spatiotemporal fine tuning of physiological processes.
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Affiliation(s)
- Erzsébet Ligeti
- Department of Physiology, Semmelweis University, Budapest, Hungary; Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany; and Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Stefan Welti
- Department of Physiology, Semmelweis University, Budapest, Hungary; Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany; and Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
| | - Klaus Scheffzek
- Department of Physiology, Semmelweis University, Budapest, Hungary; Structural and Computational Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany; and Division of Biological Chemistry, Biocenter, Innsbruck Medical University, Innsbruck, Austria
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Balanis N, Yoshigi M, Wendt MK, Schiemann WP, Carlin CR. β3 integrin-EGF receptor cross-talk activates p190RhoGAP in mouse mammary gland epithelial cells. Mol Biol Cell 2011; 22:4288-301. [PMID: 21937717 PMCID: PMC3216655 DOI: 10.1091/mbc.e10-08-0700] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Active RhoA localizes to plasma membrane, where it stimulates formation of focal adhesions and stress fibers. RhoA activity is inhibited by p190RhoGAP following integrin-mediated cell attachment to allow sampling of new adhesive environments. p190RhoGAP is itself activated by Src-dependent tyrosine phosphorylation, which facilitates complex formation with p120RasGAP. This complex then translocates to the cell surface, where p190RhoGAP down-regulates RhoA. Here we demonstrate that the epidermal growth factor receptor (EGFR) cooperates with β3 integrin to regulate p190RhoGAP activity in mouse mammary gland epithelial cells. Adhesion to fibronectin stimulates tyrosine phosphorylation of the EGFR in the absence of receptor ligands. Use of a dominant inhibitory EGFR mutant demonstrates that fibronectin-activated EGFR recruits p120RasGAP to the cell periphery. Expression of an inactive β3 integrin subunit abolishes p190RhoGAP tyrosine phosphorylation, demonstrating a mechanistic link between β3 integrin-activated Src and EGFR regulation of the RhoA inhibitor. The β3 integrin/EGFR pathway also has a positive role in formation of filopodia. Together our data suggest that EGFR constitutes an important intrinsic migratory cue since fibronectin is a key component of the microenvironment in normal mammary gland development and breast cancer. Our data also suggest that EGFR expressed at high levels has a role in eliciting cell shape changes associated with epithelial-to-mesenchymal transition.
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Affiliation(s)
- Nikolas Balanis
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH 44106, USA
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Mai A, Veltel S, Pellinen T, Padzik A, Coffey E, Marjomäki V, Ivaska J. Competitive binding of Rab21 and p120RasGAP to integrins regulates receptor traffic and migration. ACTA ACUST UNITED AC 2011; 194:291-306. [PMID: 21768288 PMCID: PMC3144408 DOI: 10.1083/jcb.201012126] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
P120RasGAP competes with Rab21 for binding to the cytoplasmic domain of integrin α-subunits, thereby promoting receptor escape from early endosomes and recycling to the plasma membrane. Integrin trafficking from and to the plasma membrane controls many aspects of cell behavior including cell motility, invasion, and cytokinesis. Recruitment of integrin cargo to the endocytic machinery is regulated by the small GTPase Rab21, but the detailed molecular mechanisms underlying integrin cargo recruitment are yet unknown. Here we identify an important role for p120RasGAP (RASA1) in the recycling of endocytosed α/β1-integrin heterodimers to the plasma membrane. Silencing of p120RasGAP attenuated integrin recycling and augmented cell motility. Mechanistically, p120RasGAP interacted with the cytoplasmic domain of integrin α-subunits via its GAP domain and competed with Rab21 for binding to endocytosed integrins. This in turn facilitated exit of the integrin from Rab21- and EEA1-positive endosomes to drive recycling. Our results assign an unexpected role for p120RasGAP in the regulation of integrin traffic in cancer cells and reveal a new concept of competitive binding of Rab GTPases and GAP proteins to receptors as a regulatory mechanism in trafficking.
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Affiliation(s)
- Anja Mai
- Turku Centre for Biotechnology, Turku 20521, Finland
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Abstract
There have been significant recent advances in the past several years in the field of neurocutaneous vascular syndromes, including the development of more stringent diagnostic criteria for PHACE syndrome, the renaming of macrocephaly-cutis marmorata telangiectatica congenita to macrocephaly-capillary malformation to accurately reflect the true nature of the syndrome, and discovery of new genetic mutations such as RASA-1. There have also been advances in the understanding and management of Sturge-Weber syndrome.PHACE syndrome is a constellation of neurologic, arterial, cardiac, ophthalmologic, and sternal abnormalities associated with infantile hemangiomas. PHACE is an acronym for Posterior fossa malformation, Hemangioma, Arterial anomalies, Coarctation of the aorta, Eye abnormalities. Some authors include an "S" for PHACE(S) to denote the association of ventral defects including Sternal clefting and Supraumbilical raphe.The accurate diagnosis and work-up of these patients require coordination of care across multiple disciplines, including neuroradiology, radiology, dermatology, neurology, surgery, and interventional radiology, among others.This paper is meant to update clinicians and researchers about important advances in these rare, important vascular syndromes, to improve care, and lay the foundation for future directions for research.
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Lorentzen A, Kinkhabwala A, Rocks O, Vartak N, Bastiaens PIH. Regulation of Ras localization by acylation enables a mode of intracellular signal propagation. Sci Signal 2010; 3:ra68. [PMID: 20858867 DOI: 10.1126/scisignal.20001370] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Growth factor stimulation generates transient H-Ras activity at the plasma membrane but sustained activity at the Golgi. Two overlapping regulatory networks control compartmentalized H-Ras activity: the guanosine diphosphate-guanosine triphosphate cycle and the acylation cycle, which constitutively traffics Ras isoforms that can be palmitoylated between intracellular membrane compartments. Quantitative imaging of H-Ras activity after decoupling of these networks revealed regulation of H-Ras activity at the plasma membrane but not at the Golgi. Nevertheless, upon stimulation with epidermal growth factor, Ras activity at the Golgi displayed a pulse-like profile similar to that at the plasma membrane but also remained high after the initial stimulus. A compartmental model that included the acylation cycle and H-Ras regulation at the plasma membrane accounted for the pulse-like profile of H-Ras activity at the Golgi but implied that sustained H-Ras activity at the Golgi required H-Ras activation at an additional compartment, which we experimentally determined to be the endoplasmic reticulum. Thus, in addition to maintaining the localization of Ras, the acylation cycle underlies a previously unknown form of signal propagation similar to radio transmission in its generation of a constitutive Ras "carrier wave" that transmits Ras activity between subcellular compartments.
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Affiliation(s)
- Anna Lorentzen
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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35
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p120Ras-GAP binds the DLC1 Rho-GAP tumor suppressor protein and inhibits its RhoA GTPase and growth-suppressing activities. Oncogene 2009; 28:1401-9. [PMID: 19151751 DOI: 10.1038/onc.2008.498] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
DLC1 (deleted in liver cancer 1), which encodes a Rho GTPase-activating protein (Rho-GAP), is a potent tumor suppressor gene that is frequently inactivated in several human cancers. DLC1 is a multidomain protein that has been shown previously to bind members of the tensin gene family. Here we show that p120Ras-GAP (Ras-GAP; also known as RASA1) interacts and extensively colocalizes with DLC1 in focal adhesions. The binding was mapped to the SH3 domain located in the N terminus of Ras-GAP and to the Rho-GAP catalytic domain located in the C terminus of the DLC1. In vitro analyses with purified proteins determined that the isolated Ras-GAP SH3 domain inhibits DLC1 Rho-GAP activity, suggesting that Ras-GAP is a negative regulator of DLC1 Rho-GAP activity. Consistent with this possibility, we found that ectopic overexpression of Ras-GAP in a Ras-GAP-insensitive tumor line impaired the growth-suppressing activity of DLC1 and increased RhoA activity in vivo. Our observations expand the complexity of proteins that regulate DLC1 function and define a novel mechanism of the cross talk between Ras and Rho GTPases.1R01CA129610
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Pamonsinlapatham P, Hadj-Slimane R, Lepelletier Y, Allain B, Toccafondi M, Garbay C, Raynaud F. p120-Ras GTPase activating protein (RasGAP): a multi-interacting protein in downstream signaling. Biochimie 2008; 91:320-8. [PMID: 19022332 DOI: 10.1016/j.biochi.2008.10.010] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Accepted: 10/16/2008] [Indexed: 11/29/2022]
Abstract
p120-RasGAP (Ras GTPase activating protein) plays a key role in the regulation of Ras-GTP bound by promoting GTP hydrolysis via its C-terminal catalytic domain. The p120-RasGAP N-terminal part contains two SH2, SH3, PH (pleckstrin homology) and CaLB/C2 (calcium-dependent phospholipid-binding domain) domains. These protein domains allow various functions, such as anti-/pro-apoptosis, proliferation and also cell migration depending of their distinct partners. The p120-RasGAP domain participates in protein-protein interactions with Akt, Aurora or RhoGAP to regulate functions described bellow. Here, we summarize, in angiogenesis and cancer, the various functional roles played by p120-RasGAP domains and their effector partners in downstream signaling.
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Affiliation(s)
- Perayot Pamonsinlapatham
- Université Paris Descartes, UFR Biomédicale, Laboratoire de Pharmacochimie Moléculaire et Cellulaire, 45 Rue des Saints-Pères, 75270 Paris Cedex 06, France
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37
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Gremer L, Gilsbach B, Ahmadian MR, Wittinghofer A. Fluoride complexes of oncogenic Ras mutants to study the Ras-RasGap interaction. Biol Chem 2008; 389:1163-71. [PMID: 18713003 DOI: 10.1515/bc.2008.132] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Down-regulation of Ras signalling is mediated by specific GTPase-activating proteins (GAPs), which stimulate the very slow GTPase reaction of Ras by 10(5)-fold. The basic features of the GAP activity involve the stabilisation of both switch regions of Ras in the transition state, and the insertion of an arginine finger. In the case of oncogenic Ras mutations, the features of the active site are disturbed. To understand these features in more detail, we have investigated the effects of oncogenic mutations of Ras and compared the GAP-stimulated GTPase reaction with the ability to form GAP-mediated aluminium or beryllium fluoride complexes. In general we find a correlation between the size of the amino acid at position 12, the GTPase activity and ability to form aluminium fluoride complexes. While Gly12 is very sensitive to even the smallest possible structural change, Gly13 is much less sensitive to steric hindrance, but is sensitive to charge. Oncogenic mutants of Ras defective in the GTPase activity can however form ground-state GppNHp complexes with GAP, which can be mimicked by beryllium fluoride binding. We show that beryllium fluoride complexes are less sensitive to structural changes and report on a state close to but different from the ground state of the GAP-stimulated GTPase reaction.
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Affiliation(s)
- Lothar Gremer
- Abteilung Strukturelle Biologie, Max-Planck-Institut für molekulare Physiologie, Otto-Hahn-Strasse 11, D-44227 Dortmund, Germany
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Abstract
Extensive research on the Ras proteins and their functions in cell physiology over the past 30 years has led to numerous insights that have revealed the involvement of Ras not only in tumorigenesis but also in many developmental disorders. Despite great strides in our understanding of the molecular and cellular mechanisms of action of the Ras proteins, the expanding roster of their downstream effectors and the complexity of the signalling cascades that they regulate indicate that much remains to be learnt.
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Affiliation(s)
- Antoine E. Karnoub
- Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
| | - Robert A. Weinberg
- Whitehead Institute for Biomedical Research and Massachusetts Institute of Technology, Cambridge, Massachusetts 02142, USA
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39
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Hershkovitz D, Bercovich D, Sprecher E, Lapidot M. RASA1 mutations may cause hereditary capillary malformations without arteriovenous malformations. Br J Dermatol 2008; 158:1035-40. [PMID: 18363760 DOI: 10.1111/j.1365-2133.2008.08493.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Capillary malformation (CM), a common vascular abnormality, is often present among family members. Recently a rare form of hereditary vascular malformation termed capillary malformation-arteriovenous malformation (CM-AVM) was shown to be caused by heterozygous mutations in RASA1, encoding RAS p21 protein activator 1. CM-AVM is characterized by multiple, small CMs associated with either AVM or arteriovenous fistula (AVF) in affected individuals or at least one of their family members. OBJECTIVES The purpose of the study was to find out whether CMs in the absence of AVM/AVF are associated with RASA1 mutations. PATIENTS/METHODS We assessed three families comprising 14 affected individuals with CMs. Linkage to the RASA1 locus was evaluated using microsatellite markers. The RASA1 gene was scrutinized for pathogenic mutations using denaturing high-performance liquid chromatography screening and direct sequencing. RESULTS AVM/AVF was identified in one of three affected families. CM without AVM/AVF was found to map in one large kindred to the RASA1 locus. Direct sequencing revealed novel heterozygous mutations segregating with CM in all three families. The mutations are predicted to result in premature termination of translation and RASA1 haplo-insufficiency. CONCLUSIONS We have demonstrated that the spectrum of clinical manifestations due to mutations in RASA1 is wider than previously thought and also includes typical CMs not associated with AVM/AVF.
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Affiliation(s)
- D Hershkovitz
- Laboratory of Molecular Dermatology, Department of Dermatology, Rambam Health Care Campus, P.O. Box 9602, Haifa 31096, Israel
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40
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Hershkovitz D, Bergman R, Sprecher E. A novel mutation in RASA1 causes capillary malformation and limb enlargement. Arch Dermatol Res 2008; 300:385-8. [DOI: 10.1007/s00403-008-0842-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2007] [Revised: 02/03/2008] [Accepted: 02/25/2008] [Indexed: 11/30/2022]
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41
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Yang C, Kazanietz MG. Chimaerins: GAPs that bridge diacylglycerol signalling and the small G-protein Rac. Biochem J 2007; 403:1-12. [PMID: 17346241 DOI: 10.1042/bj20061750] [Citation(s) in RCA: 243] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Chimaerins are the only known RhoGAPs (Rho GTPase-activating proteins) that bind phorbol ester tumour promoters and the lipid second messenger DAG (diacylglycerol), and show specific GAP activity towards the small GTPase Rac. This review summarizes our knowledge of the structure, biochemical and biological properties of chimaerins. Recent findings have established that chimaerins are regulated by tyrosine kinase and GPCRs (G-protein-coupled receptors) via PLC (phospholipase C) activation and DAG generation to promote Rac inactivation. The finding that chimaerins, along with some other proteins, are receptors for DAG changed the prevalent view that PKC (protein kinase C) isoenzymes are the only cellular molecules regulated by DAG. In addition, vigorous recent studies have begun to decipher the critical roles of chimaerins in the central nervous system, development and tumour progression.
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Affiliation(s)
- Chengfeng Yang
- Department of Pharmacology and Institute for Translational Medicine and Therapeutics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6160, USA.
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42
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Affiliation(s)
- R Schäfer
- Department of Pathology, University of Zurich, Switzerland
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43
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Wang D, Li Z, Messing EM, Wu G. The SPRY domain-containing SOCS box protein 1 (SSB-1) interacts with MET and enhances the hepatocyte growth factor-induced Erk-Elk-1-serum response element pathway. J Biol Chem 2005; 280:16393-401. [PMID: 15713673 DOI: 10.1074/jbc.m413897200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The suppressor of cytokine signaling (SOCS) protein family includes a SPRY (repeats in splA and RyR) domain-containing SOCS box protein (SSB) subfamily, which consists of four members, SSB-1, SSB-2, SSB-3, and SSB-4. These proteins contain a central SPRY domain and a C-terminal SOCS box. Although some of the SOCS protein subfamilies function as adaptors for a large family of ubiquitin-protein isopeptide ligases to regulate certain signaling pathways, the function of the SSB subfamily remains to be determined. In our previous studies, we have found that two SPRY domain-containing proteins, RanBP9 and RanBP10, interact with MET through the SPRY domain. In the present study, we explored the function of SSB proteins in the regulation of the hepatocyte growth factor (HGF)-MET signaling. Our results showed that all four SSB proteins also interacted with the MET. The MET interaction with SSB-1 was further investigated. We demonstrated that SSB-1 bound to MET tyrosine kinase domain through its SPRY domain. MET interacted with SSB-1 in both the absence and the presence of HGF, but HGF treatment resulted in the recruitment of more SSB-1 by MET. We showed that overexpression of SSB-1 but not other SSB proteins enhanced the HGF-induced serum response element (SRE)-luciferase activity. Overexpression of SSB-1 exhibited no effect on the basal level or epidermal growth factor-induced SRE-luciferase activity. SSB-1 also enhanced HGF-induced Erk phosphorylation. Suppression of SSB-1 by the RNA interference method down-regulated HGF-induced SRE-luciferase activity and decreased Elk-1 activation. These results suggest that SSB-1 may play an important role in enhancing the HGF-induced Erk-Elk-1-SRE pathway. Furthermore, we demonstrated that in response to HGF stimulation, the SSB-1 protein became phosphorylated at tyrosine residue 31. The phosphorylated SSB-1 protein bound to p120Ras-GTPase-activating protein (GAP) but did not promote the degradation of p120RasGAP, indicating that enhanced HGF-MET signaling by overexpression of SSB-1 was not dependent on p120RasGAP degradation.
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Affiliation(s)
- Dakun Wang
- Department of Urology, Department of Pathology and Laboratory Medicine, and The James P. Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York 14642, USA
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Woodcock SA, Hughes DA. p120 Ras GTPase-activating protein associates with fibroblast growth factor receptors in Drosophila. Biochem J 2004; 380:767-74. [PMID: 15030317 PMCID: PMC1224229 DOI: 10.1042/bj20031848] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2003] [Revised: 03/18/2004] [Accepted: 03/18/2004] [Indexed: 11/17/2022]
Abstract
Btl (breathless) and Htl (heartless), the two FGFRs (fibroblast growth factor receptors) in Drosophila melanogaster, control cell migration and differentiation in the developing embryo. These receptors signal through the conserved Ras/mitogen-activated protein kinase pathway, but how they regulate Ras activity is not known. The present study shows that there is a direct interaction between p120 RasGAP (Ras GTPase-activating protein), a negative regulator of Ras, and activated FGFRs in Drosophila. The interaction is dependent on the SH2 (Src homology 2) domains of RasGAP, which have been shown to interact with a phosphotyrosine residue within the consensus sequence (phospho)YXXPXD. A potential binding site that matches this consensus is found in both Btl and Htl, located between the transmembrane and kinase domains of each receptor. A peptide corresponding to this region was capable of binding RasGAP only when the tyrosine residue was phosphorylated. This tyrosine residue appears to be conserved in human FGFR-1 and mediates the association with the adapter protein CrkII, but no association between dCrk (Drosophila homologue of CrkII) and the activated FGFRs was detected. RasGAP was a substrate of the activated FGFR kinase domain, and mutation of the tyrosine residue within the potential binding site on the receptor prevented tyrosine phosphorylation of RasGAP. RasGAP attenuated FGFR signalling in vivo and this ability was dependent on both its SH2 domains and its GAP activity. On the basis of these results, we propose that RasGAP is directly recruited into activated FGFRs in Drosophila and plays a role in regulating the strength of signalling through Ras and the mitogen-activated protein kinase pathway.
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Affiliation(s)
- Simon A Woodcock
- Department of Biomolecular Sciences, University of Manchester Institute of Science and Technology, PO Box 88, Manchester M60 1QD, UK
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Li G, Zhang XC. GTP hydrolysis mechanism of Ras-like GTPases. J Mol Biol 2004; 340:921-32. [PMID: 15236956 DOI: 10.1016/j.jmb.2004.06.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2004] [Revised: 04/30/2004] [Accepted: 06/04/2004] [Indexed: 11/19/2022]
Abstract
The Ras-like GTPases regulate diverse cellular functions via the chemical cycle of binding and hydrolyzing GTP molecules. They alternate between GTP- and GDP-bound conformations. The GTP-bound conformation is biologically active and promotes a cellular function, such as signal transduction, cytoskeleton organization, protein synthesis/translocation, or a membrane budding/fusion event. GTP hydrolysis turns off the GTPase switch by converting it to the inactive GDP-bound conformation. The fundamental GTP hydrolysis mechanism by these GTPases has generated considerable interest over the last two decades but remained to be firmly established. This review provides an update on the catalytic mechanism with discussions on recent developments from kinetic, structural, and model studies in the context of the various GTP hydrolysis models proposed over the years.
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Affiliation(s)
- Guangpu Li
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 940 S.L. Young Blvd, BMSB 853, Oklahoma City, OK 73104, USA.
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Abstract
The importance of the Rho-GTPases in cancer progression, particularly in the area of metastasis, is becoming increasingly evident. This review will provide an overview of the role of the Rho-regulatory proteins in breast cancer metastatis.
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Affiliation(s)
- Min Lin
- Department of Internal Medicine, The University of Michigan Comprehensive Cancer Center, Ann Arbor, MI 48109-0948, USA
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Ohmine K, Nagai T, Tarumoto T, Miyoshi T, Muroi K, Mano H, Komatsu N, Takaku F, Ozawa K. Analysis of gene expression profiles in an imatinib-resistant cell line, KCL22/SR. Stem Cells 2004; 21:315-21. [PMID: 12743326 DOI: 10.1634/stemcells.21-3-315] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The BCR/ABL tyrosine kinase inhibitor, imatinib, has shown substantial effects in blast crises of chronic myelogenous leukemia. However, most patients relapse after an initial clinical response, indicating that drug resistance is a major problem for patients being treated with imatinib. In this study, we generated a new imatinib-resistant BCR/ABL-positive cell line, KCL22/SR. The 50% inhibitory concentration of imatinib was 11-fold higher in KCL22/SR than in the imatinib-sensitive parental cell line, KCL22. However, KCL22/SR showed no mutations in the BCR/ABL gene and no increase in the levels of BCR/ABL protein and P-glycoprotein. Furthermore, the level of phosphorylated BCR/ABL protein was suppressed by imatinib treatment, suggesting that mechanisms independent of BCR/ABL signaling are involved in the imatinib resistance in KCL22/SR cells. DNA microarray analyses demonstrated that the signal transduction-related molecules, RAS p21 protein activator and RhoA, which could affect Ras signaling, and a surface tumor antigen, L6, were upregulated, while c-Myb and activin A receptor were downregulated in KCL22/SR cells. Furthermore, imatinib treatment significantly suppressed the level of phosphorylated p44/42 in KCL22 cells but not in KCL22/SR cells, even when BCR/ABL was inhibited by imatinib. These results suggest that various mechanisms, including disturbance of Ras-mitogen-activated protein kinase signaling, are involved in imatinib resistance.
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MESH Headings
- Antineoplastic Agents/pharmacology
- Benzamides
- Cell Line, Tumor
- Drug Resistance, Neoplasm/genetics
- Fusion Proteins, bcr-abl/drug effects
- Fusion Proteins, bcr-abl/genetics
- Gene Expression Profiling
- Gene Expression Regulation, Neoplastic/drug effects
- Gene Expression Regulation, Neoplastic/genetics
- Humans
- Imatinib Mesylate
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/immunology
- MAP Kinase Signaling System/drug effects
- MAP Kinase Signaling System/physiology
- Mitogen-Activated Protein Kinase 3
- Mitogen-Activated Protein Kinases/drug effects
- Mitogen-Activated Protein Kinases/metabolism
- Mutation/drug effects
- Mutation/genetics
- Oligonucleotide Array Sequence Analysis
- Phosphorylation/drug effects
- Piperazines/pharmacology
- Pyrimidines/pharmacology
- Secondary Prevention
- Signal Transduction/drug effects
- Signal Transduction/genetics
- ras Proteins/drug effects
- ras Proteins/metabolism
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Affiliation(s)
- Ken Ohmine
- Divisions of Hematology, Cell Transplantation and Transfusion, and Functional Genomics, Jichi Medical School, Tochigi, Japan
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Abstract
Over the last two decades, a new and unifying concept of cellular organization has emerged in which modular protein-protein interactions provide an underlying framework through which signaling pathways are assembled and controlled. In this scheme, posttranslational modifications such as phosphorylation commonly exert their biological effects by regulating molecular interactions, exemplified by the ability of phosphotyrosine sites to bind selectively to SH2 domains. Although these interactions are rather simple in isolation, they can nonetheless be exploited to generate complex cellular systems. Here, I discuss experiments that have led to this view of dynamic cellular behavior and identify some current and future areas of interest in cell signaling.
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Affiliation(s)
- Tony Pawson
- Samuel Lunenfeld Research Institute, Mt. Sinai Hospital, 600 University Avenue, Toronto, ON M5G 1X5, Canada.
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Ahmadian MR, Kiel C, Stege P, Scheffzek K. Structural fingerprints of the Ras-GTPase activating proteins neurofibromin and p120GAP. J Mol Biol 2003; 329:699-710. [PMID: 12787671 DOI: 10.1016/s0022-2836(03)00514-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Ras specific GTPase activating proteins (GAPs), neurofibromin and p120GAP, bind GTP bound Ras and efficiently complement its active site. Here we present comparative data from mutations and fluorescence-based assays of the catalytic domains of both RasGAPs and interpret them using the crystal structures. Three prominent regions in RasGAPs, the arginine-finger loop, the phenylalanine-leucine-arginine (FLR) region and alpha7/variable loop contain structural fingerprints governing the GAP function. The finger loop is crucial for the stabilization of the transition state of the GTPase reaction. This function is controlled by residues proximal to the catalytic arginine, which are strikingly different between the two RasGAPs. These residues specifically determine the orientation and therefore the positioning of the arginine finger in the Ras active site. The invariant FLR region, a hallmark for RasGAPs, indirectly contributes to GTPase stimulation by forming a scaffold, which stabilizes Ras switch regions. We show that a long hydrophobic side-chain in the FLR region is crucial for this function. The alpha7/variable loop uses several conserved residues including two lysine residues, which are involved in numerous interactions with the switch I region of Ras. This region determines the specificity of the Ras-RasGAP interaction.
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Affiliation(s)
- Mohammad Reza Ahmadian
- Department Structural Biology, Max-Planck-Institute for Molecular Physiology, Otto-Hahn-Strasse 11, 44227, Dortmund, Germany
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Abstract
From the pioneering work with acute transforming retroviruses to the current post-genomic era, RAS genes have always been at the leading edge of signal transduction and molecular oncology. Yet, a complete understanding of RAS function and dysfunction - mainly in human cancer - is still to come. The knowledge that has accumulated since their discovery 30 years ago has, however, been remarkable, and should pave the way for not only solving the outstanding issues regarding RAS biology, but also for developing efficacious drugs that could have a significant impact on cancer treatment.
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Affiliation(s)
- Marcos Malumbres
- Molecular Oncology Programme, Centro Nacional de Investigaciones Oncológicas, Melchor Fernández Almagro 3, 28029 Madrid, Spain.
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