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Baković J, Yu BYK, Silva D, Baczynska M, Peak-Chew SY, Switzer A, Burchell L, Wigneshweraraj S, Vandanashree M, Gopal B, Filonenko V, Skehel M, Gout I. Redox Regulation of the Quorum-sensing Transcription Factor AgrA by Coenzyme A. Antioxidants (Basel) 2021; 10:antiox10060841. [PMID: 34070323 PMCID: PMC8228455 DOI: 10.3390/antiox10060841] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/21/2021] [Accepted: 05/21/2021] [Indexed: 12/23/2022] Open
Abstract
Staphylococcus aureus (S. aureus) is an aggressive opportunistic pathogen of prominent virulence and antibiotic resistance. These characteristics are due in part to the accessory gene regulator (agr) quorum-sensing system, which allows for the rapid adaptation of S. aureus to environmental changes and thus promotes virulence and the development of pathogenesis. AgrA is the agr system response regulator that binds to the P2 and P3 promoters and upregulates agr expression. In this study, we reveal that S. aureus AgrA is modified by covalent binding of CoA (CoAlation) in response to oxidative or metabolic stress. The sites of CoAlation were mapped by liquid chromatography tandem mass spectrometry (LC-MS/MS) and revealed that oxidation-sensing Cys199 is modified by CoA. Surface plasmon resonance (SPR) analysis showed an inhibitory effect of CoAlation on the DNA-binding activity, as CoAlated AgrA had significantly lower affinity towards the P2 and P3 promoters than non-CoAlated AgrA. Overall, this study provides novel insights into the mode of transcriptional regulation in S. aureus and further elucidates the link between the quorum-sensing and oxidation-sensing roles of the agr system.
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Affiliation(s)
- Jovana Baković
- Department of Structural and Molecular Biology, University College London, London WC1E 6BT, UK; (J.B.); (B.Y.K.Y.); (D.S.); (M.B.)
| | - Bess Yi Kun Yu
- Department of Structural and Molecular Biology, University College London, London WC1E 6BT, UK; (J.B.); (B.Y.K.Y.); (D.S.); (M.B.)
| | - Daniel Silva
- Department of Structural and Molecular Biology, University College London, London WC1E 6BT, UK; (J.B.); (B.Y.K.Y.); (D.S.); (M.B.)
| | - Maria Baczynska
- Department of Structural and Molecular Biology, University College London, London WC1E 6BT, UK; (J.B.); (B.Y.K.Y.); (D.S.); (M.B.)
| | - Sew Yeu Peak-Chew
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK; (S.Y.P.-C.); (M.S.)
| | - Amy Switzer
- Section of Microbiology, Faculty of Medicine and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK; (A.S.); (L.B.); (S.W.)
| | - Lynn Burchell
- Section of Microbiology, Faculty of Medicine and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK; (A.S.); (L.B.); (S.W.)
| | - Sivaramesh Wigneshweraraj
- Section of Microbiology, Faculty of Medicine and MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, UK; (A.S.); (L.B.); (S.W.)
| | | | - Balasubramanian Gopal
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560012, India; (M.V.); (B.G.)
| | - Valeriy Filonenko
- Department of Cell Signaling, Institute of Molecular Biology and Genetics, 143 Kyiv, Ukraine;
| | - Mark Skehel
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK; (S.Y.P.-C.); (M.S.)
| | - Ivan Gout
- Department of Structural and Molecular Biology, University College London, London WC1E 6BT, UK; (J.B.); (B.Y.K.Y.); (D.S.); (M.B.)
- Department of Cell Signaling, Institute of Molecular Biology and Genetics, 143 Kyiv, Ukraine;
- Correspondence: ; Tel.: +0044-2076794482; Fax: +0044-2076797193
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2
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McQuail J, Switzer A, Burchell L, Wigneshweraraj S. The RNA-binding protein Hfq assembles into foci-like structures in nitrogen starved Escherichia coli. J Biol Chem 2020; 295:12355-12367. [PMID: 32532816 PMCID: PMC7458820 DOI: 10.1074/jbc.ra120.014107] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/09/2020] [Indexed: 11/13/2022] Open
Abstract
The initial adaptive responses to nutrient depletion in bacteria often occur at the level of gene expression. Hfq is an RNA-binding protein present in diverse bacterial lineages that contributes to many different aspects of RNA metabolism during gene expression. Using photoactivated localization microscopy and single-molecule tracking, we demonstrate that Hfq forms a distinct and reversible focus-like structure in Escherichia coli specifically experiencing long-term nitrogen starvation. Using the ability of T7 phage to replicate in nitrogen-starved bacteria as a biological probe of E. coli cell function during nitrogen starvation, we demonstrate that Hfq foci have a role in the adaptive response of E. coli to long-term nitrogen starvation. We further show that Hfq foci formation does not depend on gene expression once nitrogen starvation has set in and occurs indepen-dently of the transcription factor N-regulatory protein C, which activates the initial adaptive response to N starvation in E. coli These results serve as a paradigm to demonstrate that bacterial adaptation to long-term nutrient starvation can be spatiotemporally coordinated and can occur independently of de novo gene expression during starvation.
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Affiliation(s)
- Josh McQuail
- Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Amy Switzer
- Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Lynn Burchell
- Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
| | - Sivaramesh Wigneshweraraj
- Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, United Kingdom
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3
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Mulvenna N, Hantke I, Burchell L, Nicod S, Bell D, Turgay K, Wigneshweraraj S. Xenogeneic modulation of the ClpCP protease of Bacillus subtilis by a phage-encoded adaptor-like protein. J Biol Chem 2019; 294:17501-17511. [PMID: 31362989 PMCID: PMC6873191 DOI: 10.1074/jbc.ra119.010007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 07/24/2019] [Indexed: 11/06/2022] Open
Abstract
Like eukaryotic and archaeal viruses, which coopt the host's cellular pathways for their replication, bacteriophages have evolved strategies to alter the metabolism of their bacterial host. SPO1 bacteriophage infection of Bacillus subtilis results in comprehensive remodeling of cellular processes, leading to conversion of the bacterial cell into a factory for phage progeny production. A cluster of 26 genes in the SPO1 genome, called the host takeover module, encodes for potentially cytotoxic proteins that specifically shut down various processes in the bacterial host, including transcription, DNA synthesis, and cell division. However, the properties and bacterial targets of many genes of the SPO1 host takeover module remain elusive. Through a systematic analysis of gene products encoded by the SPO1 host takeover module, here we identified eight gene products that attenuated B. subtilis growth. Of the eight phage gene products that attenuated bacterial growth, a 25-kDa protein called Gp53 was shown to interact with the AAA+ chaperone protein ClpC of the ClpCP protease of B. subtilis Our results further reveal that Gp53 is a phage-encoded adaptor-like protein that modulates the activity of the ClpCP protease to enable efficient SPO1 phage progeny development. In summary, our findings indicate that the bacterial ClpCP protease is the target of xenogeneic (dys)regulation by a SPO1 phage-derived factor and add Gp53 to the list of antibacterial products that target bacterial protein degradation and therefore may have utility for the development of novel antibacterial agents.
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Affiliation(s)
- Nancy Mulvenna
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Ingo Hantke
- Institute für Mikrobiologie, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419 Hannover, Germany
| | - Lynn Burchell
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - Sophie Nicod
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
| | - David Bell
- SynbiCITE, iHub, Imperial College London, White City, London W12 0BZ, United Kingdom
| | - Kürşad Turgay
- Institute für Mikrobiologie, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419 Hannover, Germany.,Max Planck Unit for the Science of Pathogens, Chariteplatz 1, 10117 Berlin, Germany
| | - Sivaramesh Wigneshweraraj
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London SW7 2AZ, United Kingdom
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4
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Tabib-Salazar A, Liu B, Shadrin A, Burchell L, Wang Z, Wang Z, Goren MG, Yosef I, Qimron U, Severinov K, Matthews SJ, Wigneshweraraj S. Full shut-off of Escherichia coli RNA-polymerase by T7 phage requires a small phage-encoded DNA-binding protein. Nucleic Acids Res 2017; 45:7697-7707. [PMID: 28486695 PMCID: PMC5569994 DOI: 10.1093/nar/gkx370] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 04/24/2017] [Indexed: 11/13/2022] Open
Abstract
Infection of Escherichia coli by the T7 phage leads to rapid and selective inhibition of the bacterial RNA polymerase (RNAP) by the 7 kDa T7 protein Gp2. We describe the identification and functional and structural characterisation of a novel 7 kDa T7 protein, Gp5.7, which adopts a winged helix-turn-helix-like structure and specifically represses transcription initiation from host RNAP-dependent promoters on the phage genome via a mechanism that involves interaction with DNA and the bacterial RNAP. Whereas Gp2 is indispensable for T7 growth in E. coli, we show that Gp5.7 is required for optimal infection outcome. Our findings provide novel insights into how phages fine-tune the activity of the host transcription machinery to ensure both successful and efficient phage progeny development.
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Affiliation(s)
- Aline Tabib-Salazar
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Bing Liu
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Andrey Shadrin
- G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow 142290, Russia
| | - Lynn Burchell
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Zhexin Wang
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Zhihao Wang
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, London SW7 2AZ, UK
| | - Moran G Goren
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Ido Yosef
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Udi Qimron
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Konstantin Severinov
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, 190 Frelinghuysen Road, Piscataway, NJ 08854-8020, USA
| | - Steve J Matthews
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, London SW7 2AZ, UK
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5
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du Plessis J, Cloete R, Burchell L, Sarkar P, Warren RM, Christoffels A, Wigneshweraraj S, Sampson SL. Exploring the potential of T7 bacteriophage protein Gp2 as a novel inhibitor of mycobacterial RNA polymerase. Tuberculosis (Edinb) 2017; 106:82-90. [PMID: 28802409 DOI: 10.1016/j.tube.2017.07.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 07/04/2017] [Accepted: 07/13/2017] [Indexed: 11/17/2022]
Abstract
Over the past six decades, there has been a decline in novel therapies to treat tuberculosis, while the causative agent of this disease has become increasingly resistant to current treatment regimens. Bacteriophages (phages) are able to kill bacterial cells and understanding this process could lead to novel insights for the treatment of mycobacterial infections. Phages inhibit bacterial gene transcription through phage-encoded proteins which bind to RNA polymerase (RNAP), thereby preventing bacterial transcription. Gp2, a T7 phage protein which binds to the beta prime (β') subunit of RNAP in Escherichia coli, has been well characterized in this regard. Here, we aimed to determine whether Gp2 is able to inhibit RNAP in Mycobacterium tuberculosis as this may provide new possibilities for inhibiting the growth of this deadly pathogen. Results from an electrophoretic mobility shift assay and in vitro transcription assay revealed that Gp2 binds to mycobacterial RNAP and inhibits transcription; however to a much lesser degree than in E. coli. To further understand the molecular basis of these results, a series of in silico techniques were used to assess the interaction between mycobacterial RNAP and Gp2, providing valuable insight into the characteristics of this protein-protein interaction.
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Affiliation(s)
- J du Plessis
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, SA MRC Centre for TB Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa.
| | - R Cloete
- South African National Bioinformatics Institute (SANBI), SA Medical Research Council Bioinformatics Unit, University of the Western Cape, South Africa.
| | - L Burchell
- MRC Centre for Molecular Bacteriology and Infection, Faculty of Medicine, South Kensington Campus, Imperial College, United Kingdom.
| | - P Sarkar
- MRC Centre for Molecular Bacteriology and Infection, Faculty of Medicine, South Kensington Campus, Imperial College, United Kingdom.
| | - R M Warren
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, SA MRC Centre for TB Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa.
| | - A Christoffels
- South African National Bioinformatics Institute (SANBI), SA Medical Research Council Bioinformatics Unit, University of the Western Cape, South Africa.
| | - S Wigneshweraraj
- MRC Centre for Molecular Bacteriology and Infection, Faculty of Medicine, South Kensington Campus, Imperial College, United Kingdom.
| | - S L Sampson
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, SA MRC Centre for TB Research, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa.
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6
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Brown DR, Sheppard CM, Burchell L, Matthews S, Wigneshweraraj S. The Xp10 Bacteriophage Protein P7 Inhibits Transcription by the Major and Major Variant Forms of the Host RNA Polymerase via a Common Mechanism. J Mol Biol 2016; 428:3911-3919. [PMID: 27515396 PMCID: PMC5053324 DOI: 10.1016/j.jmb.2016.08.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/02/2016] [Accepted: 08/03/2016] [Indexed: 01/24/2023]
Abstract
The σ factor is a functionally obligatory subunit of the bacterial transcription machinery, the RNA polymerase. Bacteriophage-encoded small proteins that either modulate or inhibit the bacterial RNAP to allow the temporal regulation of bacteriophage gene expression often target the activity of the major bacterial σ factor, σ70. Previously, we showed that during Xanthomonas oryzae phage Xp10 infection, the phage protein P7 inhibits the host RNAP by preventing the productive engagement with the promoter and simultaneously displaces the σ70 factor from the RNAP. In this study, we demonstrate that P7 also inhibits the productive engagement of the bacterial RNAP containing the major variant bacterial σ factor, σ54, with its cognate promoter. The results suggest for the first time that the major variant form of the host RNAP can also be targeted by bacteriophage-encoded transcription regulatory proteins. Since the major and major variant σ factor interacting surfaces in the RNAP substantially overlap, but different regions of σ70 and σ54 are used for binding to the RNAP, our results further underscore the importance of the σ–RNAP interface in bacterial RNAP function and regulation and potentially for intervention by antibacterials. Xp10 phage transcription regulator P7 inhibits transcription by RNAP containing σ54. P7 prevents the productive engagement of the σ54–RNAP with the promoter DNA. • P7 disrupts preformed σ54–RNAP-promoter complexes.
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Affiliation(s)
- D R Brown
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, SW7 2AZ, UK.
| | - C M Sheppard
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, SW7 2AZ, UK
| | - L Burchell
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, SW7 2AZ, UK
| | - S Matthews
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, SW7 2AZ, UK
| | - S Wigneshweraraj
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, SW7 2AZ, UK.
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7
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Figueira R, Brown DR, Ferreira D, Eldridge MJG, Burchell L, Pan Z, Helaine S, Wigneshweraraj S. Adaptation to sustained nitrogen starvation by Escherichia coli requires the eukaryote-like serine/threonine kinase YeaG. Sci Rep 2015; 5:17524. [PMID: 26621053 PMCID: PMC4664914 DOI: 10.1038/srep17524] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 10/30/2015] [Indexed: 12/13/2022] Open
Abstract
The Escherichia coli eukaryote-like serine/threonine kinase, encoded by yeaG, is expressed in response to diverse stresses, including nitrogen (N) starvation. A role for yeaG in bacterial stress response is unknown. Here we reveal for the first time that wild-type E. coli displays metabolic heterogeneity following sustained periods of N starvation, with the metabolically active population displaying compromised viability. In contrast, such heterogeneity in metabolic activity is not observed in an E. coli ∆yeaG mutant, which continues to exist as a single and metabolically active population and thus displays an overall compromised ability to survive sustained periods of N starvation. The mechanism by which yeaG acts, involves the transcriptional repression of two toxin/antitoxin modules, mqsR/mqsA and dinJ/yafQ. This, consequently, has a positive effect on the expression of rpoS, the master regulator of the general bacterial stress response. Overall, results indicate that yeaG is required to fully execute the rpoS-dependent gene expression program to allow E. coli to adapt to sustained N starvation and unravels a novel facet to the regulatory basis that underpins adaptive response to N stress.
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Affiliation(s)
- Rita Figueira
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, UK
| | - Daniel R Brown
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, UK
| | - Delfim Ferreira
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, UK
| | - Matthew J G Eldridge
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, UK
| | - Lynn Burchell
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, UK
| | - Zhensheng Pan
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, UK
| | - Sophie Helaine
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, UK
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Nicod SS, Weinzierl ROJ, Burchell L, Escalera-Maurer A, James EH, Wigneshweraraj S. Systematic mutational analysis of the LytTR DNA binding domain of Staphylococcus aureus virulence gene transcription factor AgrA. Nucleic Acids Res 2014; 42:12523-36. [PMID: 25352558 PMCID: PMC4227749 DOI: 10.1093/nar/gku1015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Most DNA-binding bacterial transcription factors contact DNA through a recognition α-helix in their DNA-binding domains. An emerging class of DNA-binding transcription factors, predominantly found in pathogenic bacteria interact with the DNA via a relatively novel type of DNA-binding domain, called the LytTR domain, which mainly comprises β strands. Even though the crystal structure of the LytTR domain of the virulence gene transcription factor AgrA from Staphylococcus aureus bound to its cognate DNA sequence is available, the contribution of specific amino acid residues in the LytTR domain of AgrA to transcription activation remains elusive. Here, for the first time, we have systematically investigated the role of amino acid residues in transcription activation in a LytTR domain-containing transcription factor. Our analysis, which involves in vivo and in vitro analyses and molecular dynamics simulations of S. aureus AgrA identifies a highly conserved tyrosine residue, Y229, as a major amino acid determinant for maximal activation of transcription by AgrA and provides novel insights into structure-function relationships in S. aureus AgrA.
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Affiliation(s)
- Sophie S Nicod
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, London, UK
| | | | - Lynn Burchell
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, London, UK
| | | | - Ellen H James
- MRC Centre for Molecular Microbiology and Infection, Imperial College London, London, UK
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9
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Bill A, Rosethorne EM, Kent TC, Fawcett L, Burchell L, van Diepen MT, Marelli A, Batalov S, Miraglia L, Orth AP, Renaud NA, Charlton SJ, Gosling M, Gaither LA, Groot-Kormelink PJ. High throughput mutagenesis for identification of residues regulating human prostacyclin (hIP) receptor expression and function. PLoS One 2014; 9:e97973. [PMID: 24886841 PMCID: PMC4041722 DOI: 10.1371/journal.pone.0097973] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 04/25/2014] [Indexed: 12/12/2022] Open
Abstract
The human prostacyclin receptor (hIP receptor) is a seven-transmembrane G protein-coupled receptor (GPCR) that plays a critical role in vascular smooth muscle relaxation and platelet aggregation. hIP receptor dysfunction has been implicated in numerous cardiovascular abnormalities, including myocardial infarction, hypertension, thrombosis and atherosclerosis. Genomic sequencing has discovered several genetic variations in the PTGIR gene coding for hIP receptor, however, its structure-function relationship has not been sufficiently explored. Here we set out to investigate the applicability of high throughput random mutagenesis to study the structure-function relationship of hIP receptor. While chemical mutagenesis was not suitable to generate a mutagenesis library with sufficient coverage, our data demonstrate error-prone PCR (epPCR) mediated mutagenesis as a valuable method for the unbiased screening of residues regulating hIP receptor function and expression. Here we describe the generation and functional characterization of an epPCR derived mutagenesis library compromising >4000 mutants of the hIP receptor. We introduce next generation sequencing as a useful tool to validate the quality of mutagenesis libraries by providing information about the coverage, mutation rate and mutational bias. We identified 18 mutants of the hIP receptor that were expressed at the cell surface, but demonstrated impaired receptor function. A total of 38 non-synonymous mutations were identified within the coding region of the hIP receptor, mapping to 36 distinct residues, including several mutations previously reported to affect the signaling of the hIP receptor. Thus, our data demonstrates epPCR mediated random mutagenesis as a valuable and practical method to study the structure-function relationship of GPCRs.
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Affiliation(s)
- Anke Bill
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Elizabeth M. Rosethorne
- Respiratory Disease Area, Novartis Institutes for Biomedical Research, Horsham, United Kingdom
| | - Toby C. Kent
- Respiratory Disease Area, Novartis Institutes for Biomedical Research, Horsham, United Kingdom
| | - Lindsay Fawcett
- Respiratory Disease Area, Novartis Institutes for Biomedical Research, Horsham, United Kingdom
| | - Lynn Burchell
- Respiratory Disease Area, Novartis Institutes for Biomedical Research, Horsham, United Kingdom
| | - Michiel T. van Diepen
- Respiratory Disease Area, Novartis Institutes for Biomedical Research, Horsham, United Kingdom
| | - Anthony Marelli
- Infectious Diseases, Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Sergey Batalov
- Infectious Diseases, Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Loren Miraglia
- Infectious Diseases, Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Anthony P. Orth
- Infectious Diseases, Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Nicole A. Renaud
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Steven J. Charlton
- Respiratory Disease Area, Novartis Institutes for Biomedical Research, Horsham, United Kingdom
| | - Martin Gosling
- Respiratory Disease Area, Novartis Institutes for Biomedical Research, Horsham, United Kingdom
| | - L. Alex Gaither
- Developmental and Molecular Pathways, Novartis Institutes for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Paul J. Groot-Kormelink
- Respiratory Disease Area, Novartis Institutes for Biomedical Research, Horsham, United Kingdom
- Musculoskeletal Disease Area, Novartis Institutes for Biomedical Research, Basel, Switzerland
- * E-mail:
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10
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Spratt DE, Martinez-Torres RJ, Noh YJ, Mercier P, Manczyk N, Barber KR, Aguirre JD, Burchell L, Purkiss A, Walden H, Shaw GS. A molecular explanation for the recessive nature of parkin-linked Parkinson's disease. Nat Commun 2013; 4:1983. [PMID: 23770917 PMCID: PMC3709501 DOI: 10.1038/ncomms2983] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 05/03/2013] [Indexed: 12/12/2022] Open
Abstract
Mutations in the park2 gene, encoding the RING-inBetweenRING-RING E3 ubiquitin ligase parkin, cause 50% of autosomal recessive juvenile Parkinsonism cases. More than 70 known pathogenic mutations occur throughout parkin, many of which cluster in the inhibitory amino-terminal ubiquitin-like domain, and the carboxy-terminal RING2 domain that is indispensable for ubiquitin transfer. A structural rationale showing how autosomal recessive juvenile Parkinsonism mutations alter parkin function is still lacking. Here we show that the structure of parkin RING2 is distinct from canonical RING E3 ligases and lacks key elements required for E2-conjugating enzyme recruitment. Several pathogenic mutations in RING2 alter the environment of a single surface-exposed catalytic cysteine to inhibit ubiquitination. Native parkin adopts a globular inhibited conformation in solution facilitated by the association of the ubiquitin-like domain with the RING-inBetweenRING-RING C-terminus. Autosomal recessive juvenile Parkinsonism mutations disrupt this conformation. Finally, parkin autoubiquitinates only in cis, providing a molecular explanation for the recessive nature of autosomal recessive juvenile Parkinsonism.
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Affiliation(s)
- Donald E Spratt
- Department of Biochemistry, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada N6A 5C1
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Kondapalli C, Kazlauskaite A, Zhang N, Woodroof HI, Campbell DG, Gourlay R, Burchell L, Walden H, Macartney TJ, Deak M, Knebel A, Alessi DR, Muqit MMK. PINK1 is activated by mitochondrial membrane potential depolarization and stimulates Parkin E3 ligase activity by phosphorylating Serine 65. Open Biol 2012; 2:120080. [PMID: 22724072 PMCID: PMC3376738 DOI: 10.1098/rsob.120080] [Citation(s) in RCA: 659] [Impact Index Per Article: 54.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2012] [Accepted: 04/30/2012] [Indexed: 11/23/2022] Open
Abstract
Missense mutations in PTEN-induced kinase 1 (PINK1) cause autosomal-recessive inherited Parkinson's disease (PD). We have exploited our recent discovery that recombinant insect PINK1 is catalytically active to test whether PINK1 directly phosphorylates 15 proteins encoded by PD-associated genes as well as proteins reported to bind PINK1. We have discovered that insect PINK1 efficiently phosphorylates only one of these proteins, namely the E3 ligase Parkin. We have mapped the phosphorylation site to a highly conserved residue within the Ubl domain of Parkin at Ser(65). We show that human PINK1 is specifically activated by mitochondrial membrane potential (Δψm) depolarization, enabling it to phosphorylate Parkin at Ser(65). We further show that phosphorylation of Parkin at Ser(65) leads to marked activation of its E3 ligase activity that is prevented by mutation of Ser(65) or inactivation of PINK1. We provide evidence that once activated, PINK1 autophosphorylates at several residues, including Thr(257), which is accompanied by an electrophoretic mobility band-shift. These results provide the first evidence that PINK1 is activated following Δψm depolarization and suggest that PINK1 directly phosphorylates and activates Parkin. Our findings indicate that monitoring phosphorylation of Parkin at Ser(65) and/or PINK1 at Thr(257) represent the first biomarkers for examining activity of the PINK1-Parkin signalling pathway in vivo. Our findings also suggest that small molecule activators of Parkin that mimic the effect of PINK1 phosphorylation may confer therapeutic benefit for PD.
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Affiliation(s)
- Chandana Kondapalli
- MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Agne Kazlauskaite
- MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Ning Zhang
- MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Helen I. Woodroof
- MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
- Division of Cell Signalling and Immunology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - David G. Campbell
- MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Robert Gourlay
- MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Lynn Burchell
- Protein Structure and Function Laboratory, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Helen Walden
- Protein Structure and Function Laboratory, Cancer Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Thomas J. Macartney
- MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Maria Deak
- MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Axel Knebel
- MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Dario R. Alessi
- MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Miratul M. K. Muqit
- MRC Protein Phosphorylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
- College of Medicine, Dentistry and Nursing, University of Dundee, Dundee DD1 5EH, UK
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Burchell L, Chaugule VK, Walden H. Small, N-terminal tags activate Parkin E3 ubiquitin ligase activity by disrupting its autoinhibited conformation. PLoS One 2012; 7:e34748. [PMID: 22496854 PMCID: PMC3319606 DOI: 10.1371/journal.pone.0034748] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Accepted: 03/08/2012] [Indexed: 11/30/2022] Open
Abstract
Parkin is an E3 ubiquitin ligase, mutations in which cause Autosomal Recessive Parkinson's Disease. Many studies aimed at understanding Parkin function, regulation and dysfunction are performed using N-terminal epitope tags. We report here that the use of small tags such as FLAG, cMyc and HA, influence the physical stability and activity of Parkin in and out of cells, perturbing the autoinhibited native state of Parkin, resulting in an active-for-autoubiquitination species.
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Affiliation(s)
- Lynn Burchell
- Protein Structure and Function laboratory, The London Research Institute of Cancer Research UK, Lincoln's Inn Fields Laboratories, London, United Kingdom
| | - Viduth K. Chaugule
- Protein Structure and Function laboratory, The London Research Institute of Cancer Research UK, Lincoln's Inn Fields Laboratories, London, United Kingdom
| | - Helen Walden
- Protein Structure and Function laboratory, The London Research Institute of Cancer Research UK, Lincoln's Inn Fields Laboratories, London, United Kingdom
- * E-mail:
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Chaugule VK, Burchell L, Barber KR, Sidhu A, Leslie SJ, Shaw GS, Walden H. Autoregulation of Parkin activity through its ubiquitin-like domain. EMBO J 2011; 30:2853-67. [PMID: 21694720 DOI: 10.1038/emboj.2011.204] [Citation(s) in RCA: 250] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 05/26/2011] [Indexed: 11/09/2022] Open
Abstract
Parkin is an E3-ubiquitin ligase belonging to the RBR (RING-InBetweenRING-RING family), and is involved in the neurodegenerative disorder Parkinson's disease. Autosomal recessive juvenile Parkinsonism, which is one of the most common familial forms of the disease, is directly linked to mutations in the parkin gene. However, the molecular mechanisms of Parkin dysfunction in the disease state remain to be established. We now demonstrate that the ubiquitin-like domain of Parkin functions to inhibit its autoubiquitination. Moreover pathogenic Parkin mutations disrupt this autoinhibition, resulting in a constitutively active molecule. In addition, we show that the mechanism of autoregulation involves ubiquitin binding by a C-terminal region of Parkin. Our observations provide important molecular insights into the underlying basis of Parkinson's disease, and in the regulation of RBR E3-ligase activity.
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Affiliation(s)
- Viduth K Chaugule
- Protein Structure and Function Laboratory, Cancer Research UK, London Research Institute, London, UK
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García-Nafría J, Burchell L, Takezawa M, Rzechorzek NJ, Fogg MJ, Wilson KS. The structure of the genomic Bacillus subtilis dUTPase: novel features in the Phe-lid. Acta Crystallogr D Biol Crystallogr 2010; 66:953-61. [PMID: 20823546 DOI: 10.1107/s0907444910026272] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Accepted: 07/04/2010] [Indexed: 11/11/2022]
Abstract
dUTPases are a ubiquitous family of enzymes that are essential for all organisms and catalyse the breakdown of 2-deoxyuridine triphosphate (dUTP). In Bacillus subtilis there are two homotrimeric dUTPases: a genomic and a prophage form. Here, the structures of the genomic dUTPase and of its complex with the substrate analogue dUpNHpp and calcium are described, both at 1.85 A resolution. The overall fold resembles that of previously solved trimeric dUTPases. The C-terminus, which contains one of the conserved sequence motifs, is disordered in both structures. The crystal of the complex contains six independent protomers which accommodate six dUpNHpp molecules, with three triphosphates in the trans conformation and the other three in the active gauche conformation. The structure of the complex confirms the role of several key residues that are involved in ligand binding and the position of the catalytic water. Asp82, which has previously been proposed to act as a general base, points away from the active site. In the complex Ser64 reorients in order to hydrogen bond the phosphate chain of the substrate. A novel feature has been identified: the position in the sequence of the ;Phe-lid', which packs against the uracil moiety, is adjacent to motif III, whereas in all other dUTPase structures the lid is in a conserved position in motif V of the flexible C-terminal arm. This requires a reconsideration of some aspects of the accepted mechanism.
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15
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Woś M, Sanak M, Burchell L, Mosser A, Soja J, Olechnowicz H, Szczeklik A, Busse W. Rhinovirus Infection in Lower Airways of Asthmatic Patients. J Allergy Clin Immunol 2006. [DOI: 10.1016/j.jaci.2005.12.1239] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
OBJECTIVE To assess cerebrovascular mortality in a UK cohort of patients with pituitary adenoma known to have increased incidence of cerebrovascular accidents (CVA). METHODS A total of 334 patients treated at the Royal Marsden Hospital (RMH) between 1962 and 1986 with surgery and postoperative radiotherapy were followed up via the NHS Central Register (NHSCR) to identify deaths and emigrations. The causes of death were assessed by NHSCR-based death certificates and coded according to the 9th revision of ICD. Follow-up was censored at age 85, on emigration or cancellation of NHSCR. Thirteen patients could not be traced. A total of 4982 person-years was accumulated in the cohort. Expected numbers of deaths were computed from the national age-, sex- and period-specific mortality rates for England and Wales. RESULTS In the pituitary adenoma cohort, 128 deaths were observed compared to 80.9 expected [relative risk (RR) of death 1.58 (95% CI: 1.32-1.90)]. There were 33 cerebrovascular deaths compared with 8.04 expected (RR 4.11, 95% CI 2.84-5.75). Three deaths were from subarachnoid haemorrhage compared to 0.54 expected (RR 5.51, 95% CI 1.14-16.09). There was an increased cerebrovascular mortality in women (RR 6.93, 95% CI 4.29-10.60) compared to men (RR 2.4, 95% CI 1.24-4.20; P = 0.002) and in patients having debulking surgery (RR 5.19, 95% CI 3.50-7.42) compared to biopsy/no surgery (RR 1.33, 95% CI 0.27-3.88; P = 0.02). The RR in patients with nonsecretory tumours was 3.65 (95% CI 2.26-5.58), compared with 5.23 (95% CI 2.25-10.30) in secretory tumours (P = 0.4). The effect of age at radiotherapy was not significant (P = 0.4). CONCLUSION Patients with pituitary adenoma treated with surgery and radiotherapy have an increased risk of cerebrovascular mortality compared to the general population, which mirrors the increased incidence of CVA. The possible risk factors include hypopituitarism, radiotherapy and extent of surgery but none are at present proven causes. The evaluation of new treatment strategies should not only assess intermediate end-points of tumour and endocrine control but should concentrate on long-term survival with particular emphasis on CVA incidence and mortality.
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Affiliation(s)
- M Brada
- Neuro-oncology Unit and Academic Unit of Radiotherapy, Downs Road, Sutton, Surrey, UK.
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Jalali R, Brada M, Perks JR, Warrington AP, Traish D, Burchell L, McNair H, Thomas DG, Robinson S, Johnston DG. Stereotactic conformal radiotherapy for pituitary adenomas: technique and preliminary experience. Clin Endocrinol (Oxf) 2000; 52:695-702. [PMID: 10848873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
OBJECTIVE Stereotactic conformal radiotherapy (SCRT) is a high precision technique of fractionated radiotherapy which ensures accurate delivery of radiation with reduction in the volume of normal tissue irradiated as compared to conventional external beam radiotherapy. We describe the technique and preliminary experience of SCRT in patients with residual and recurrent pituitary adenomas. PATIENTS AND METHODS Between February 1995 and March 1999, 22 patients (mean age: 45.3, range: 20-67 years) with residual or recurrent pituitary adenomas (13 nonfunctioning, nine secretory) were treated with SCRT. All were immobilized in a relocatable Gill-Thomas-Cosman (GTC) frame and tumour was localized on a postcontrast planning computerized tomography (CT) and MRI scan. The gross tumour volume (GTV) and the critical structures were outlined on contiguous 2-3 mm separated slices. A margin of 5 mm (12 patients) to 10 mm (10 patients) was grown around GTV in three-dimensions (3-D) to generate the planning target volume (PTV). The treatment was delivered by three (five patients) and four (17 patients) maximally separated conformal fixed fields with each field conformed to the shape of the tumour using customized lead alloy blocks (19 patients) or multileaf collimator (three patients). The patients were treated on a 6-MV linear accelerator to a dose of 45 Gy in 25 fractions (18 patients) and 50 Gy in 30 fractions (four patients). RESULTS The technique of SCRT has become a part of the routine work of the radiotherapy department. The treatment was well tolerated with minimal acute toxicity. One patient developed transient quadrantanopia 2 weeks after treatment with full recovery after a short course of corticosteroids. One patient had a transient visual deterioration 7 months after treatment due to cystic degeneration of the tumour which fully recovered following surgical decompression. Nine of the 15 patients presenting with visual impairment had improvement after treatment and the visual status remained stable in all others. One patient with acromegaly and one with a prolactinoma achieved normalization of elevated hormonal abnormality four and 10 months after SCRT, respectively. The remaining seven patients with a secretory adenoma had declining hormone levels at last follow-up. Newly initiated hormone replacement therapy was required in five patients. At a median follow-up of 9 months (range 1-44 months), the 1 and 2 year actuarial progression free and overall survival were 100%. CONCLUSION Stereotactic conformal radiotherapy is a high precision technique suitable for the treatment of pituitary adenomas requiring radiotherapy. Preliminary results suggest effective tumour control and low toxicity within the range expected for conventional external beam radiotherapy. While the technique is of potential benefit in reducing the volume of normal brain irradiated, the advantages in terms of sustained tumour control and reduced toxicity over conventional radiotherapy need to be demonstrated in long-term prospective studies.
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Affiliation(s)
- R Jalali
- Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Trust, London, UK
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18
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Abstract
BACKGROUND AND PURPOSE Patients with pituitary adenomas are effectively treated with a combination of surgery, radiotherapy, and medical therapy. Nevertheless, long-term studies suggest increased mortality that is independent of tumor control, with cerebrovascular accidents (CVA) as the major contributing cause. The purpose of this study was to define the frequency of CVAs in a cohort of patients with pituitary adenoma and identify potential predisposing factors. PATIENTS AND METHODS A cohort of 331 United Kingdom (UK) residents with pituitary adenoma treated at the Royal Marsden Hospital (RMH) between 1962 and 1986 was studied. The frequency of CVA was assessed from RMH and referring hospital records and clinicians, by postal questionnaire of referring hospitals and general practitioners, and by examination of all death certificates. The data were analyzed by actuarial methods, and risk factors were assessed by multivariate analysis. The data were compared to the incidence of CVA in the general population using a published UK population cohort. RESULTS Sixty-four of 331 patients developed CVA after primary treatment of pituitary adenoma. The actuarial incidence of CVA was 4% (95% CI: 2-7%) at 5 years, 11% (95% CI: 8-14%) at 10 years, and 21% (95% CI: 16-28%) at 20 years measured from the date of radiotherapy. The relative risk of CVA compared to the general population in the UK was 4.1. Age was an independent predictive factor for CVA. However, the relative risk in comparison to the general population was independent of age. The relative risk of developing CVA was higher in women compared to men, in patients undergoing debulking surgery compared to less radical procedures, and in patients diagnosed and treated in the 1980s compared to previous decades. The dose of radiotherapy was an additional independent prognostic factor on multivariate analysis. CONCLUSION Patients with pituitary adenoma treated with surgery and radiotherapy have a significantly increased risk of CVA compared to the general population. The factors which may contribute to the increased risk include the presence of pituitary adenoma and consequent endocrine disturbances and the treatment, particularly the extent of surgery and the dose of radiotherapy. When assessing the value of treatment strategies, it is therefore important to include not only intermediate endpoints of tumor and hormonal control, but also late toxicity, including the incidence of CVA and overall survival as the primary endpoint. The potential predisposing factors for CVA need further elucidation to develop treatment strategies with lower risk and consequently, reduced mortality.
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Affiliation(s)
- M Brada
- Neuro-oncology Unit, The Institute of Cancer Research and the Royal Marsden NHS Trust, Sutton, Surrey, UK.
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Moynihan C, Bliss JM, Davidson J, Burchell L, Horwich A. Evaluation of adjuvant psychological therapy in patients with testicular cancer: randomised controlled trial. BMJ 1998; 316:429-35. [PMID: 9492666 PMCID: PMC2665582 DOI: 10.1136/bmj.316.7129.429] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To determine the efficacy of adjuvant psychological therapy in patients with testicular cancer and to compare the characteristics and psychosocial outcomes of men who agreed to participate with those who declined to participate in a randomised trial of psychological intervention. DESIGN Newly diagnosed patients were asked to participate in a randomised trial of psychological support compared with standard medical care. Participants and non-participants completed self assessment questionnaires at baseline and at 2, 4 and 12 months. SETTING Testicular Tumour Unit of the Royal Marsden Hospital. SUBJECTS 73 of 184 (40%) eligible patients agreed to enter the randomised trial (participants) and 81 (44%) declined to participate but agreed to complete further assessments (non-participants). 30 patients wanted no further contact with the researchers. OUTCOME MEASURES Hospital anxiety and depression scale, psychosocial adjustment to illness scale, Rotterdam symptom checklist, mental adjustment to cancer scale. Only scores on the hospital anxiety and depression scale are reported for evaluating treatment efficacy. RESULTS 111 of 184 (60%) eligible men declined to participate in the trial. Patients with stage I disease were most likely to refuse to participate. A patient was less likely to participate if he had low volume disease and was receiving no further treatment. Likelihood of participation was associated with stage of disease and with type of primary treatment (P < 0.001 for heterogeneity). Patients with early stage disease (P < 0.001) and fewer physical symptoms (P < 0.001) were less likely to participate. Psychosocial factors associated with participation included anxious preoccupation regarding disease (P = 0.01). There were no differences in outcome between participants and non-participants during follow up. Patients seemed to gain little benefit from adjuvant psychological therapy. At 2 months change from baseline favoured the treated group in the anxiety subscale (mean difference between groups -1.41 (95% confidence interval -2.86 to 0.03)). This was not sustained when adjusted for factors related to the disease. By 12 months change from baseline seemed to favour the control group (mean difference between groups 1.66 (-0.18 to 3.50)). CONCLUSIONS Patients with testicular cancer seem to have considerable coping abilities. Those who declined to participate in the trial differed from those who participated. Those who agreed to participate may comprise the clinical group who perceive a need for psychological support. No evidence was found to indicate a need for routinely offering adjuvant psychological therapy.
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Affiliation(s)
- C Moynihan
- Academic Department of Radiotherapy and Oncology, Royal Marsden NHS Trust, Sutton, Surrey.
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