1
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Li T, Chao TC, Tsai KL. Structures and compositional dynamics of Mediator in transcription regulation. Curr Opin Struct Biol 2024; 88:102892. [PMID: 39067114 DOI: 10.1016/j.sbi.2024.102892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 06/30/2024] [Accepted: 07/05/2024] [Indexed: 07/30/2024]
Abstract
The eukaryotic Mediator, comprising a large Core (cMED) and a dissociable CDK8 kinase module (CKM), functions as a critical coregulator during RNA polymerase II (RNAPII) transcription. cMED recruits RNAPII and facilitates the assembly of the pre-initiation complex (PIC) at promoters. In contrast, CKM prevents RNAPII binding to cMED while simultaneously exerting positive or negative influence on gene transcription through its kinase function. Recent structural studies on cMED and CKM have revealed their intricate architectures and subunit interactions. Here, we explore these structures, providing a comprehensive insight into Mediator (cMED-CKM) architecture and its potential mechanism in regulating RNAPII transcription. Additionally, we discuss the remaining puzzles that require further investigation to fully understand how cMED coordinates with CKM to regulate transcription in various events.
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Affiliation(s)
- Tao Li
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston TX, USA
| | - Ti-Chun Chao
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston TX, USA
| | - Kuang-Lei Tsai
- Department of Biochemistry and Molecular Biology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston TX, USA.
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2
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Schiano C, Luongo L, Maione S, Napoli C. Mediator complex in neurological disease. Life Sci 2023; 329:121986. [PMID: 37516429 DOI: 10.1016/j.lfs.2023.121986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 07/18/2023] [Accepted: 07/26/2023] [Indexed: 07/31/2023]
Abstract
Neurological diseases, including traumatic brain injuries, stroke (haemorrhagic and ischemic), and inherent neurodegenerative diseases cause acquired disability in humans, representing a leading cause of death worldwide. The Mediator complex (MED) is a large, evolutionarily conserved multiprotein that facilities the interaction between transcription factors and RNA Polymerase II in eukaryotes. Some MED subunits have been found altered in the brain, although their specific functions in neurodegenerative diseases are not fully understood. Mutations in MED subunits were associated with a wide range of genetic diseases for MED12, MED13, MED13L, MED20, MED23, MED25, and CDK8 genes. In addition, MED12 and MED23 were deregulated in the Alzheimer's Disease. Interestingly, most of the genomic mutations have been found in the subunits of the kinase module. To date, there is only one evidence on MED1 involvement in post-stroke cognitive deficits. Although the underlying neurodegenerative disorders may be different, we are confident that the signal cascades of the biological-cognitive mechanisms of brain adaptation, which begin after brain deterioration, may also differ. Here, we analysed relevant studies in English published up to June 2023. They were identified through a search of electronic databases including PubMed, Medline, EMBASE and Scopus, including search terms such as "Mediator complex", "neurological disease", "brains". Thematic content analysis was conducted to collect and summarize all studies demonstrating MED alteration to understand the role of this central transcriptional regulatory complex in the brain. Improved and deeper knowledge of the regulatory mechanisms in neurological diseases can increase the ability of physicians to predict onset and progression, thereby improving diagnostic care and providing appropriate treatment decisions.
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Affiliation(s)
- Concetta Schiano
- Department of Advanced Medical and Surgical Sciences (DAMSS), University of Campania "Luigi Vanvitelli", Italy.
| | - Livio Luongo
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Italy; IRCSS, Neuromed, Pozzilli, Italy
| | - Sabatino Maione
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Italy; IRCSS, Neuromed, Pozzilli, Italy
| | - Claudio Napoli
- Department of Advanced Medical and Surgical Sciences (DAMSS), University of Campania "Luigi Vanvitelli", Italy; Clinical Department of Internal Medicine and Specialistic Units, Division of Clinical Immunology and Immunohematology, Transfusion Medicine, and Transplant Immunology (SIMT), Regional Reference Laboratory of Transplant Immunology (LIT), Azienda Universitaria Policlinico (AOU), Italy
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3
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Jullien D, Guillou E, Bernat-Fabre S, Payet A, Bourbon HMG, Boube M. Inducible degradation of the Drosophila Mediator subunit Med19 reveals its role in regulating developmental but not constitutively-expressed genes. PLoS One 2022; 17:e0275613. [PMID: 36445897 PMCID: PMC9707739 DOI: 10.1371/journal.pone.0275613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 09/20/2022] [Indexed: 11/30/2022] Open
Abstract
The multi-subunit Mediator complex plays a critical role in gene expression by bridging enhancer-bound transcription factors and the RNA polymerase II machinery. Although experimental case studies suggest differential roles of Mediator subunits, a comprehensive view of the specific set of genes regulated by individual subunits in a developing tissue is still missing. Here we address this fundamental question by focusing on the Med19 subunit and using the Drosophila wing imaginal disc as a developmental model. By coupling auxin-inducible degradation of endogenous Med19 in vivo with RNA-seq, we got access to the early consequences of Med19 elimination on gene expression. Differential gene expression analysis reveals that Med19 is not globally required for mRNA transcription but specifically regulates positively or negatively less than a quarter of the expressed genes. By crossing our transcriptomic data with those of Drosophila gene expression profile database, we found that Med19-dependent genes are highly enriched with spatially-regulated genes while the expression of most constitutively expressed genes is not affected upon Med19 loss. Whereas globally downregulation does not exceed upregulation, we identified a functional class of genes encoding spatially-regulated transcription factors, and more generally developmental regulators, responding unidirectionally to Med19 loss with an expression collapse. Moreover, we show in vivo that the Notch-responsive wingless and the E(spl)-C genes require Med19 for their expression. Combined with experimental evidences suggesting that Med19 could function as a direct transcriptional effector of Notch signaling, our data support a model in which Med19 plays a critical role in the transcriptional activation of developmental genes in response to cell signaling pathways.
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Affiliation(s)
- Denis Jullien
- Center for Integrative Biology, Molecular Cellular and Developmental (MCD) Biology Unit UMR 5077, Federal University of Toulouse, Toulouse, France
- * E-mail: (MB); (DJ)
| | - Emmanuelle Guillou
- Center for Integrative Biology, Molecular Cellular and Developmental (MCD) Biology Unit UMR 5077, Federal University of Toulouse, Toulouse, France
| | - Sandra Bernat-Fabre
- Center for Integrative Biology, Molecular Cellular and Developmental (MCD) Biology Unit UMR 5077, Federal University of Toulouse, Toulouse, France
| | - Adeline Payet
- Center for Integrative Biology, Molecular Cellular and Developmental (MCD) Biology Unit UMR 5077, Federal University of Toulouse, Toulouse, France
| | - Henri-Marc G. Bourbon
- Center for Integrative Biology, Molecular Cellular and Developmental (MCD) Biology Unit UMR 5077, Federal University of Toulouse, Toulouse, France
| | - Muriel Boube
- Center for Integrative Biology, Molecular Cellular and Developmental (MCD) Biology Unit UMR 5077, Federal University of Toulouse, Toulouse, France
- RESTORE Research Center, Université de Toulouse, INSERM 1301, CNRS 5070, EFS, ENVT, Toulouse, France
- * E-mail: (MB); (DJ)
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4
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Mashukova A, Forteza R, Shah VN, Salas PJ. The cell polarity kinase Par1b/MARK2 activation selects specific NF-kB transcripts via phosphorylation of core mediator Med17/TRAP80. Mol Biol Cell 2021; 32:690-702. [PMID: 33596087 PMCID: PMC8108508 DOI: 10.1091/mbc.e20-10-0646] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Par1b/MARK2 is a Ser/Thr kinase with pleiotropic effects that participates in the generation of apico-basal polarity in Caenorhabditis elegans. It is phosphorylated by atypical PKC(ι/λ) in Thr595 and inhibited. Because previous work showed a decrease in atypical protein kinase C (aPKC) activity under proinflammatory conditions, we analyzed the hypothesis that the resulting decrease in Thr595-MARK2 with increased kinase activity may also participate in innate immunity. We confirmed that pT595-MARK2 was decreased under inflammatory stimulation. The increase in MARK2 activity was verified by Par3 delocalization and rescue with a specific inhibitor. MARK2 overexpression significantly enhanced the transcriptional activity of NF-kB for a subset of transcripts. It also resulted in phosphorylation of a single band (∼Mr 80,000) coimmunoprecipitating with RelA, identified as Med17. In vitro phosphorylation showed direct phosphorylation of Med17 in Ser152 by recombinant MARK2. Expression of S152D-Med17 mimicked the effect of MARK2 activation on downstream transcriptional regulation, which was antagonized by S152A-Med17. The decrease in pThr595 phosphorylation was validated in aPKC-deficient mouse jejunal mucosae. The transcriptional effects were confirmed in transcriptome analysis and transcript enrichment determinations in cells expressing S152D-Med17. We conclude that theMARK2-Med17 axis represents a novel form of cross-talk between polarity signaling and transcriptional regulation including, but not restricted to, innate immunity responses.
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Affiliation(s)
- Anastasia Mashukova
- Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL 33136.,Department of Medical Education, Dr. Kiran C. Patel College of Allopathic Medicine, Nova Southeastern University, Fort Lauderdale, FL 33314
| | - Radia Forteza
- Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL 33136
| | - Viraj N Shah
- Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL 33136
| | - Pedro J Salas
- Department of Cell Biology, University of Miami Miller School of Medicine, Miami, FL 33136
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5
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Wang Y, Li J, Li J, Li P, Wang L, Di L. An Enhancer-Based Analysis Revealed a New Function of Androgen Receptor in Tumor Cell Immune Evasion. Front Genet 2020; 11:595550. [PMID: 33343635 PMCID: PMC7738566 DOI: 10.3389/fgene.2020.595550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Accepted: 11/02/2020] [Indexed: 12/12/2022] Open
Abstract
Cancer is characterized by dysregulation at multiple levels, such as gene transcription. Enhancers are well-studied transcription regulators that can enhance target transcripts through DNA loop formation mediated by chromosome folding. The gain or loss of the interaction between an enhancer and its target gene has a critical effect on gene expression. In this study, we analyzed GRO-seq data to identify active enhancers from seven common cancer cell lines and studied the function of these enhancers across multiple cancer types. By constructing an "enhancer effect score" (EES), we found a significant correlation between EES and tumor-infiltrating lymphocytes (TILs) in prostate cancer. Further analysis revealed that androgen receptor (AR) plays an important role in regulating the immune checkpoint gene PVR via its enhancer. These results suggest that AR contributes to prostate cancer aggressiveness by promoting cancer cell immune evasion.
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Affiliation(s)
| | | | | | | | | | - Lijun Di
- Cancer Center, Faculty of Health Sciences, University of Macau, Macau, China
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6
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Hoppe C, Bowles JR, Minchington TG, Sutcliffe C, Upadhyai P, Rattray M, Ashe HL. Modulation of the Promoter Activation Rate Dictates the Transcriptional Response to Graded BMP Signaling Levels in the Drosophila Embryo. Dev Cell 2020; 54:727-741.e7. [PMID: 32758422 PMCID: PMC7527239 DOI: 10.1016/j.devcel.2020.07.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 05/13/2020] [Accepted: 07/11/2020] [Indexed: 01/08/2023]
Abstract
Morphogen gradients specify cell fates during development, with a classic example being the bone morphogenetic protein (BMP) gradient's conserved role in embryonic dorsal-ventral axis patterning. Here, we elucidate how the BMP gradient is interpreted in the Drosophila embryo by combining live imaging with computational modeling to infer transcriptional burst parameters at single-cell resolution. By comparing burst kinetics in cells receiving different levels of BMP signaling, we show that BMP signaling controls burst frequency by regulating the promoter activation rate. We provide evidence that the promoter activation rate is influenced by both enhancer and promoter sequences, whereas Pol II loading rate is primarily modulated by the enhancer. Consistent with BMP-dependent regulation of burst frequency, the numbers of BMP target gene transcripts per cell are graded across their expression domains. We suggest that graded mRNA output is a general feature of morphogen gradient interpretation and discuss how this can impact on cell-fate decisions.
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Affiliation(s)
- Caroline Hoppe
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| | - Jonathan R Bowles
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| | - Thomas G Minchington
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| | - Catherine Sutcliffe
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| | - Priyanka Upadhyai
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK
| | - Magnus Rattray
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK.
| | - Hilary L Ashe
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9PT, UK.
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7
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André KM, Sipos EH, Soutourina J. Mediator Roles Going Beyond Transcription. Trends Genet 2020; 37:224-234. [PMID: 32921511 DOI: 10.1016/j.tig.2020.08.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 08/19/2020] [Accepted: 08/20/2020] [Indexed: 12/25/2022]
Abstract
Dysfunctions of nuclear processes including transcription and DNA repair lead to severe human diseases. Gaining an understanding of how these processes operate in the crowded context of chromatin can be particularly challenging. Mediator is a large multiprotein complex conserved in eukaryotes with a key coactivator role in the regulation of RNA polymerase (Pol) II transcription. Despite intensive studies, the molecular mechanisms underlying Mediator function remain to be fully understood. Novel findings have provided insights into the relationship between Mediator and chromatin architecture, revealed its role in connecting transcription with DNA repair and proposed an emerging mechanism of phase separation involving Mediator condensates. Recent developments in the field suggest multiple functions of Mediator going beyond transcriptional processes per se that would explain its involvement in various human pathologies.
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Affiliation(s)
- Kévin M André
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Eliet H Sipos
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France
| | - Julie Soutourina
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.
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Jeffery HM, Weinzierl ROJ. Multivalent and Bidirectional Binding of Transcriptional Transactivation Domains to the MED25 Coactivator. Biomolecules 2020; 10:biom10091205. [PMID: 32825095 PMCID: PMC7564715 DOI: 10.3390/biom10091205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/14/2020] [Accepted: 08/17/2020] [Indexed: 11/16/2022] Open
Abstract
The human mediator subunit MED25 acts as a coactivator that binds the transcriptional activation domains (TADs) present in various cellular and viral gene-specific transcription factors. Previous studies, including on NMR measurements and site-directed mutagenesis, have only yielded low-resolution models that are difficult to refine further by experimental means. Here, we apply computational molecular dynamics simulations to study the interactions of two different TADs from the human transcription factor ETV5 (ERM) and herpes virus VP16-H1 with MED25. Like other well-studied coactivator-TAD complexes, the interactions of these intrinsically disordered domains with the coactivator surface are temporary and highly dynamic (‘fuzzy’). Due to the fact that the MED25 TAD-binding region is organized as an elongated cleft, we specifically asked whether these TADs are capable of binding in either orientation and how this could be achieved structurally and energetically. The binding of both the ETV5 and VP16-TADs in either orientation appears to be possible but occurs in a conformationally distinct manner and utilizes different sets of hydrophobic residues present in the TADs to drive the interactions. We propose that MED25 and at least a subset of human TADs specifically evolved a redundant set of molecular interaction patterns to allow binding to particular coactivators without major prior spatial constraints.
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Affiliation(s)
- Heather M. Jeffery
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK;
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Robert O. J. Weinzierl
- Department of Life Sciences, Imperial College London, London SW7 2AZ, UK;
- Correspondence:
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9
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Immarigeon C, Bernat-Fabre S, Guillou E, Verger A, Prince E, Benmedjahed MA, Payet A, Couralet M, Monte D, Villeret V, Bourbon HM, Boube M. Mediator complex subunit Med19 binds directly GATA transcription factors and is required with Med1 for GATA-driven gene regulation in vivo. J Biol Chem 2020; 295:13617-13629. [PMID: 32737196 DOI: 10.1074/jbc.ra120.013728] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 07/21/2020] [Indexed: 02/02/2023] Open
Abstract
The evolutionarily conserved multiprotein Mediator complex (MED) serves as an interface between DNA-bound transcription factors (TFs) and the RNA Pol II machinery. It has been proposed that each TF interacts with a dedicated MED subunit to induce specific transcriptional responses. But are these binary partnerships sufficient to mediate TF functions? We have previously established that the Med1 Mediator subunit serves as a cofactor of GATA TFs in Drosophila, as shown in mammals. Here, we observe mutant phenotype similarities between another subunit, Med19, and the Drosophila GATA TF Pannier (Pnr), suggesting functional interaction. We further show that Med19 physically interacts with the Drosophila GATA TFs, Pnr and Serpent (Srp), in vivo and in vitro through their conserved C-zinc finger domains. Moreover, Med19 loss of function experiments in vivo or in cellulo indicate that it is required for Pnr- and Srp-dependent gene expression, suggesting general GATA cofactor functions. Interestingly, Med19 but not Med1 is critical for the regulation of all tested GATA target genes, implying shared or differential use of MED subunits by GATAs depending on the target gene. Lastly, we show a direct interaction between Med19 and Med1 by GST pulldown experiments indicating privileged contacts between these two subunits of the MED middle module. Together, these findings identify Med19/Med1 as a composite GATA TF interface and suggest that binary MED subunit-TF partnerships are probably oversimplified models. We propose several mechanisms to account for the transcriptional regulation of GATA-targeted genes.
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Affiliation(s)
- Clément Immarigeon
- Centre de Biologie Integrative CBD, UMR5547 CNRS/UPS, Université de Toulouse, Toulouse Cedex, France
| | - Sandra Bernat-Fabre
- Centre de Biologie Integrative CBD, UMR5547 CNRS/UPS, Université de Toulouse, Toulouse Cedex, France
| | - Emmanuelle Guillou
- Centre de Biologie Integrative CBD, UMR5547 CNRS/UPS, Université de Toulouse, Toulouse Cedex, France
| | - Alexis Verger
- Inserm, CHU Lille, Institut Pasteur de Lille, CNRS ERL 9002 Integrative Structural Biology, Université Lille, Lille, France
| | - Elodie Prince
- Centre de Biologie Integrative CBD, UMR5547 CNRS/UPS, Université de Toulouse, Toulouse Cedex, France
| | - Mohamed A Benmedjahed
- Centre de Biologie Integrative CBD, UMR5547 CNRS/UPS, Université de Toulouse, Toulouse Cedex, France
| | - Adeline Payet
- Centre de Biologie Integrative CBD, UMR5547 CNRS/UPS, Université de Toulouse, Toulouse Cedex, France
| | - Marie Couralet
- Centre de Biologie Integrative CBD, UMR5547 CNRS/UPS, Université de Toulouse, Toulouse Cedex, France
| | - Didier Monte
- Inserm, CHU Lille, Institut Pasteur de Lille, CNRS ERL 9002 Integrative Structural Biology, Université Lille, Lille, France
| | - Vincent Villeret
- Inserm, CHU Lille, Institut Pasteur de Lille, CNRS ERL 9002 Integrative Structural Biology, Université Lille, Lille, France
| | - Henri-Marc Bourbon
- Centre de Biologie Integrative CBD, UMR5547 CNRS/UPS, Université de Toulouse, Toulouse Cedex, France
| | - Muriel Boube
- Centre de Biologie Integrative CBD, UMR5547 CNRS/UPS, Université de Toulouse, Toulouse Cedex, France.
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