113 research outputs found

    Myeloproliferative disorder FOP-FGFR1 fusion kinase recruits phosphoinositide-3 kinase and phospholipase Cγ at the centrosome

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    <p>Abstract</p> <p>Background</p> <p>The t(6;8) translocation found in rare and agressive myeloproliferative disorders results in a chimeric gene encoding the FOP-FGFR1 fusion protein. This protein comprises the N-terminal region of the centrosomal protein FOP and the tyrosine kinase of the FGFR1 receptor. FOP-FGFR1 is localized at the centrosome where it exerts a constitutive kinase activity.</p> <p>Results</p> <p>We show that FOP-FGFR1 interacts with the large centrosomal protein CAP350 and that CAP350 is necessary for FOP-FGFR1 localisation at centrosome. FOP-FGFR1 activates the phosphoinositide-3 kinase (PI3K) pathway. We show that p85 interacts with tyrosine 475 of FOP-FGFR1, which is located in a YXXM consensus binding sequence for an SH2 domain of p85. This interaction is in part responsible for PI3K activation. Ba/F3 cells that express FOP-FGFR1 mutated at tyrosine 475 have reduced proliferative ability. Treatment with PI3K pathway inhibitors induces death of FOP-FGFR1 expressing cells. FOP-FGFR1 also recruits phospholipase Cγ1 (PLCγ1) at the centrosome. We show that this enzyme is recruited by FOP-FGFR1 at the centrosome during interphase.</p> <p>Conclusion</p> <p>These results delineate a particular type of oncogenic mechanism by which an ectopic kinase recruits its substrates at the centrosome whence unappropriate signaling induces continuous cell growth and MPD.</p

    La Recherche en Chimie aux Frontières de la Connaissance

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    National audienceMixed research units are building blocks, flexible but permanent, in rapidly evolving fields of research. Several measures shape the activities of research teams and thus give rise to “poles of research”. They also help consolidate national networks, identify strong points, boost the sharing of top-level equipment and stimulate collaboration between academics and industrialists. Chemists’ diverse activities lie on a thematic continuum that reaches beyond disciplinary bounds and crisscrosses the industrial and academic spheres. The dichotomy between, on the one hand, the structure in terms of disciplines used by the authorities in charge and, on the other hand, the socioeconomic priorities set by funding agencies should enable scientists to pursue topnotch research. It should also lead to the emergence of new concepts corresponding to breakthroughs that will reshape chemistry in the future.L’Unité Mixte de Recherche est la brique élémentaire, souple et pérenne d’un paysage de la recherche en évolution rapide. De nombreux dispositifs viennent structurer l’activité de ces équipes pour faire émerger des pôles de recherche, consolider le maillage des réseaux nationaux, identifier les points forts, mutualiser des équipements de haut niveau et promouvoir les collaborations académiques et industrielles. La diversité de l’activité des chimistes se place dans un continuum thématique dépassant les frontières disciplinaires et traversant les mondes académiques et industriels. La dichotomie entre les structures disciplinaires de nos tutelles et l’affichage de défis socio-économiques par les agences de financement doivent permettre aux acteurs de mettre en œuvre des recherches de très haut niveau tout en favorisant l’émergence et la description de nouveaux concepts en rupture qui permettront de construire la chimie de demain

    The maintenance of centriole appendages and motile cilia basal body anchoring relies on TBCCD1

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    Centrosomes are organelles consisting of two structurally and functionally distinct centrioles, with the mother centriole having complex distal (DA) and subdistal appendages (SDA). Despite their importance, how appendages are assembled and maintained remains unclear. This study investigated human TBCCD1, a centrosomal protein essential for centrosome positioning, to uncover its localization and role at centrioles. We found that TBCCD1 localizes at both proximal and distal regions of the two centrioles, forming a complex structure spanning from SDA to DA and extending inside and outside the centriole lumen. TBCCD1 depletion caused centrosome mispositioning, which was partially rescued by taxol, and the loss of microtubules (MTs) anchored to centrosomes. TBCCD1 depletion also reduced levels of SDA proteins involved in MT anchoring such as Centriolin/CEP110, Ninein, and CEP170. Additionally, TBCCD1 was essential for the correct positioning of motile cilia basal bodies and associated structures in Paramecium. This study reveals that TBCCD1 is an evolutionarily conserved protein essential for centriole and basal body localization and appendage assembly and maintenance. A BioID screening also linked TBCCD1 to ciliopathy-associated protein networks.info:eu-repo/semantics/publishedVersio

    Développement d'une trousse de dosage d'organokines par spectrométrie de masse

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    Lors d'une prise en charge thérapeutique, l'identification de marqueurs biologiques permettant un meilleur diagnostic ainsi qu'une caractérisation évolutive du patient est essentielle. A cet égard, les organokines occupent une place importante car elles sont considérées comme des médiateurs moléculaires de la communication (cross-talk) inter-organes. Nous développons actuellement une méthode de quantification multiplexe de ces organokines. Cette recherche s'inscrit dans une des thématiques phares de l'Institut de Recherche Santé de l'UMONS et résulte d'une collaboration entre 6 services de l'Institut dans le domaine de la biomédecine intégrative. L'identification d'altérations du cross-talk inter-organes vise au développement futur de nouvelles stratégies thérapeutiques dans différents contextes pathologiques. Les organokines sont produites à partir de divers organes tels le tissu adipeux (adipokines), les muscles striés squelettiques (myokines), le foie (hépatokines), ou encore le cerveau (neurokines). Chacune de ces molécules est relarguée dans la circulation sanguine et agit ensuite à distance au niveau d'autres tissus et organes, jouant un rôle essentiel dans la coordination et le maintien de l'homéostasie, notamment métabolique. Il est aujourd'hui reconnu qu'une production ainsi qu'une libération excessive et inappropriée de ces organokines participe au développement et à la progression de pathologies comme l'obésité, le diabète de type 2 et les maladies cardiovasculaires. Actuellement, les organokines sont dosées individuellement par l'utilisation de tests ELISA ou RIA. Ces approches, non seulement coûteuses, n'existent pas pour toutes les organokines d'intérêt. Dans ce contexte, la spectrométrie de masse, approche très sensible, permet la quantification simultanée de nombreuses protéines dans différentes matrices biologiques dont le sérum ou le plasma. Ce projet implique une approche translationnelle directement en lien avec la clinique. Cette approche permettra d'acquérir une vision globale et intégrée des mécanismes de communication inter-organes impliqués dans les pathologies étudiées et de développer ainsi des stratégies thérapeutiques innovantes

    C11orf70 Mutations Disrupting the Intraflagellar Transport-Dependent Assembly of Multiple Axonemal Dyneins Cause Primary Ciliary Dyskinesia

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    Primary ciliary dyskinesia (PCD) is a genetically and phenotypically heterogeneous disorder characterized by destructive respiratory disease and laterality abnormalities due to randomized left-right body asymmetry. PCD is mostly caused by mutations affecting the core axoneme structure of motile cilia that is essential for movement. Genes that cause PCD when mutated include a group that encode proteins essential for the assembly of the ciliary dynein motors and the active transport process that delivers them from their cytoplasmic assembly site into the axoneme. We screened a cohort of affected individuals for disease-causing mutations using a targeted next generation sequencing panel and identified two unrelated families (three affected children) with mutations in the uncharacterized C11orf70 gene (official gene name CFAP300). The affected children share a consistent PCD phenotype from early life with laterality defects and immotile respiratory cilia displaying combined loss of inner and outer dynein arms (IDA+ODA). Phylogenetic analysis shows C11orf70 is highly conserved, distributed across species similarly to proteins involved in the intraflagellar transport (IFT)-dependant assembly of axonemal dyneins. Paramecium C11orf70 RNAi knockdown led to combined loss of ciliary IDA+ODA with reduced cilia beating and swim velocity. Tagged C11orf70 in Paramecium and Chlamydomonas localizes mainly in the cytoplasm with a small amount in the ciliary component. IFT139/TTC21B (IFT-A protein) and FLA10 (IFT kinesin) depletion experiments show that its transport within cilia is IFT dependent. During ciliogenesis, C11orf70 accumulates at the ciliary tips in a similar distribution to the IFT-B protein IFT46. In summary, C11orf70 is essential for assembly of dynein arms and C11orf70 mutations cause defective cilia motility and PCD

    Mutations in Outer Dynein Arm Heavy Chain DNAH9 Cause Motile Cilia Defects and Situs Inversus

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    Motile cilia move body fluids and gametes and the beating of cilia lining the airway epithelial surfaces ensures that they are kept clear and protected from inhaled pathogens and consequent respiratory infections. Dynein motor proteins provide mechanical force for cilia beating. Dynein mutations are a common cause of primary ciliary dyskinesia (PCD), an inherited condition characterized by deficient mucociliary clearance and chronic respiratory disease coupled with laterality disturbances and subfertility. Using next-generation sequencing, we detected mutations in the ciliary outer dynein arm (ODA) heavy chain gene DNAH9 in individuals from PCD clinics with situs inversus and in one case male infertility. DNAH9 and its partner heavy chain DNAH5 localize to type 2 ODAs of the distal cilium and in DNAH9-mutated nasal respiratory epithelial cilia we found a loss of DNAH9/DNAH5-containing type 2 ODAs that was restricted to the distal cilia region. This confers a reduced beating frequency with a subtle beating pattern defect affecting the motility of the distal cilia portion. 3D electron tomography ultrastructural studies confirmed regional loss of ODAs from the distal cilium, manifesting as either loss of whole ODA or partial loss of ODA volume. Paramecium DNAH9 knockdown confirms an evolutionarily conserved function for DNAH9 in cilia motility and ODA stability. We find that DNAH9 is widely expressed in the airways, despite DNAH9 mutations appearing to confer symptoms restricted to the upper respiratory tract. In summary, DNAH9 mutations reduce cilia function but some respiratory mucociliary clearance potential may be retained, widening the PCD disease spectrum.</p

    Fine-mapping of prostate cancer susceptibility loci in a large meta-analysis identifies candidate causal variants

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    Prostate cancer is a polygenic disease with a large heritable component. A number of common, low-penetrance prostate cancer risk loci have been identified through GWAS. Here we apply the Bayesian multivariate variable selection algorithm JAM to fine-map 84 prostate cancer susceptibility loci, using summary data from a large European ancestry meta-analysis. We observe evidence for multiple independent signals at 12 regions and 99 risk signals overall. Only 15 original GWAS tag SNPs remain among the catalogue of candidate variants identified; the remainder are replaced by more likely candidates. Biological annotation of our credible set of variants indicates significant enrichment within promoter and enhancer elements, and transcription factor-binding sites, including AR, ERG and FOXA1. In 40 regions at least one variant is colocalised with an eQTL in prostate cancer tissue. The refined set of candidate variants substantially increase the proportion of familial relative risk explained by these known susceptibility regions, which highlights the importance of fine-mapping studies and has implications for clinical risk profiling. © 2018 The Author(s).Prostate cancer is a polygenic disease with a large heritable component. A number of common, low-penetrance prostate cancer risk loci have been identified through GWAS. Here we apply the Bayesian multivariate variable selection algorithm JAM to fine-map 84 prostate cancer susceptibility loci, using summary data from a large European ancestry meta-analysis. We observe evidence for multiple independent signals at 12 regions and 99 risk signals overall. Only 15 original GWAS tag SNPs remain among the catalogue of candidate variants identified; the remainder are replaced by more likely candidates. Biological annotation of our credible set of variants indicates significant enrichment within promoter and enhancer elements, and transcription factor-binding sites, including AR, ERG and FOXA1. In 40 regions at least one variant is colocalised with an eQTL in prostate cancer tissue. The refined set of candidate variants substantially increase the proportion of familial relative risk explained by these known susceptibility regions, which highlights the importance of fine-mapping studies and has implications for clinical risk profiling. © 2018 The Author(s).Peer reviewe

    Germline variation at 8q24 and prostate cancer risk in men of European ancestry

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    Chromosome 8q24 is a susceptibility locus for multiple cancers, including prostate cancer. Here we combine genetic data across the 8q24 susceptibility region from 71,535 prostate cancer cases and 52,935 controls of European ancestry to define the overall contribution of germline variation at 8q24 to prostate cancer risk. We identify 12 independent risk signals for prostate cancer (p < 4.28 × 10−15), including three risk variants that have yet to be reported. From a polygenic risk score (PRS) model, derived to assess the cumulative effect of risk variants at 8q24, men in the top 1% of the PRS have a 4-fold (95%CI = 3.62–4.40) greater risk compared to the population average. These 12 variants account for ~25% of what can be currently explained of the familial risk of prostate cancer by known genetic risk factors. These findings highlight the overwhelming contribution of germline variation at 8q24 on prostate cancer risk which has implications for population risk stratification
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