Dissertations / Theses on the topic 'Protéines de surface cellulaire'
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Martel, Laurence. "Méthodes d'analyse de surface appliquées à l'étude de protéines." Phd thesis, Université Joseph Fourier (Grenoble), 2002. http://tel.archives-ouvertes.fr/tel-00006293.
Jung, Heung-Chae. "Protéine de nucléation de la glace : son expression et son utilisation pour l'ancrage de protéines étrangères à la surface cellulaire bactérienne." Compiègne, 1998. http://www.theses.fr/1998COMP1147.
Parzy, Daniel. "Protéine-kinases et ligands de surface : contribution à l'étude de la communication intra- et extra-cellulaire chez Plasmodium falciparum." Aix-Marseille 2, 2000. http://www.theses.fr/2000AIX22097.
Romero, Saavedra Luis Félipe. "Systematic analysis of surface proteins in Enterococci : discovery of potential targets for vaccine development." Caen, 2015. http://www.theses.fr/2015CAEN2013.
Enterococci, most commonly regarded as members of the microbial flora of the gastro intestinal tract, have emerged as human pathogens of significant concern in the last decades. Principally due to their innate and acquired resistance to antibiotics, the research for new therapeutic alternatives is needed. Surface proteins play important roles in bacterial interactions between the cell and its environment, making them ideal targets for drugs and vaccine development, mainly because of their ability to interact with the host immune system. In this study, we identified and characterized some of the immunogenic surface-related proteins present in a vancomycin-resistant Enterococcus faecium clinical isolate. The identified proteins were evaluated as potential targets for vaccine development. The protein candidates were identified either by three different surface protein extraction methods or by analysis of transcriptomic data from a mouse peritonitis model. We selected for this study eight surface related-proteins, six from the proteomic approaches (BML, DdcP, LysM, PBP5, PpiC and SCP) and two (AdcAfm and PsaAfm) from the transcriptomic analysis. We were able to demonstrate that rabbit polyclonal antibodies raised against the purified recombinant proteins induced specific opsonic antibodies that mediated killing of five enterococcal clinical strains. Furthermore, we showed that passive immunization with seven of the anti-protein sera significantly reduced the bacterial load of E. Faecium E155 in mice. Altogether, our results demonstrate the effectiveness of these protein antigens as promising vaccine candidates against enterococcal infections as well as the feasibility of these proteomic and transcriptomic approaches to identify novel protein antigens
Gross, Julien. "Caractérisation de surfaces biofonctionnalisées pour l’étude de protéines de la chaîne respiratoire par spectroscopie infrarouge couplée à l’électrochimie." Strasbourg, 2011. http://www.theses.fr/2011STRA6140.
This work is about the functionalization of surfaces for the study of membranes proteins from the respiratory chain with the help of the differential spectroscopy. In the first time, the study of the cytochrome c oxidase named ba3 from Thermus thermophilus was done. It is described, that when the pH increases, homotropic electrostatic interactions disrupt the midpoint potentials of the protein. This study has highlighted the crucial role of the heme propionates in the mechanism of the protein. Then, the protein-protein interaction between two soluble hemoproteins from the respiratory chain of the same organism was studied. A complete characterization of the two isolated proteins is carried out and the formed complex is analysed. This study shows the importance of the heme propionates, which play a crucial role in this interaction and allowed us to characterize the interaction in the molecular level. Finally, a more practical application of the surface functionalization was conducted with the study of a cathode of a biopile. This project allowed us to develop a new technique for the immobilization of proteins, using 3D gold nanoparticles. We have access, through the cyclic voltammetry, to the midpoint potentials of the proteins and we can study the electron transfer. This method was first developed on the laccase from Bacillus subtilis, and then applied to the proteins already studied. The midpoint potentials obtained from the immobilized system and those obtained in solution are compared
Malandrin, Laurence. "Les protéines de surface de pseudomonas syringae (sensu lato) : description, variabilité et application taxonomique." Angers, 1995. http://www.theses.fr/1995ANGE0015.
Jegou, Antoine. "Etude de l'adhésion gamétique par mesure de force : modulation des propriétés d'adhésion par organisation des protéines membranaires." Paris 7, 2008. http://www.theses.fr/2008PA077111.
In mammals, fertilization consists in a sequence of biological events that ends with the adhesion and the fusion of two gamete membranes. In this thesis, we develop an experimental technique to study the early stage of the adhesion between a single mouse spermatozoon and an oocyte under physiological conditions. We adapt the Biomembrane Force Probe to the study of gamete interactions and measure the evolution of the traction force between the two cells during the separation phase following a short contact. We show the existence of two types (called "E" and "V") of microdomains at the oocyte surface, which differ in their adhesion properties. The transmembrane protein CD9 tetraspanin, which is expressed by the oocyte, is necessary for the fusion process. It controls the formation of protein complexes. Measurements of the interaction forces show that CD9-null oocytes have no "E" domains. This result shows that CD9 participates in the adhesion from the very onset. Our experiments describe the modulation of gamete adhesion by the organisation of receptors at the oocyte surface. Moreover, for short contact times, single point attachment events allow us to probe the elastic response of the oocyte, to measure its effective membrane viscosity by pulling tethers, and to estimate the adhesion energy between its membrane and its cytoskeleton. The biophysical approach we developed in this thesis is complementary to biological strategies. It appears as a promising tool for the study of adhesion at the molecular level
Presle, Adrien. "Le facteur de restriction viral BST2/Tetherin ancre les Midbody post-cytokinétiques à la surface cellulaire." Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS476.
The Midbody Remnant (MBR) is a structure that arises once cytokinetic abscission, the last step in cell division, is completed. Then, the MBR interacts with the cell surface and can play various roles in development, polarisation or cell proliferation. I first characterized a new MBR purification method. This study revealed that BST2, a protein known to anchor enveloped viruses to the cell surface, is enriched at the MBR. I thus focused on BST2 and its role at the MBR, especially in the interaction with the recipient cell plasma membrane. I fist confirmed by microscopy the enrichment of BST2 t the MBR. Similarly to viruses, the absence of BST2 increases the detachment of MBRs from the cell surface. They are thus released in the extracellular medium, increasing their transfer to neighbouring cells. Mechanistically, in parallel with virion restriction, BST2 dimerization and GPI anchor are both required for proper localization and functions of BST2 at the MBR. Using purified MBRs, we showed that BST2 at the midbody membrane -but not at the plasma membrane of the cell- is important for MBR retention to the cell surface. Altogether, these results show that BST2 localizes at the midbody remnant to promote its retention at the cell surface of non-infected cells. I propose that, in a way analogous to enveloped virions, BST2 tethers midbody remnants and participates in promoting their proper interaction with recipient cells
Baz, Ahsene. "Modulation des protéines prosomales (proteasomales) au cours de la différenciation des cellules leucémiques lymphoblastiques humaines (CCRF-CEM) induite par le phorbol-myristate-acétate (PMA) et leurs relations avec les protéines de surface et le complexe majeur d'histocompatibilité (MHC)." Montpellier 1, 1997. http://www.theses.fr/1997MON1T029.
Baujard-Lamotte, Lucie. "Interactions surfaces-protéines-cellules : Adsorption de la fibronectine sur supports modèles et influence sur le comportement cellulaire." Cergy-Pontoise, 2007. http://biblioweb.u-cergy.fr/theses/07CERG0390.pdf.
In living tissues, cell behaviors depend on close connections between cells and their environment, the extracellular matrix (ECM). For in vitro cell culture experiments, a classic strategy to improve cell culture is to coat cell culture supports by an ECM protein which is able to promote cell adhesion, like fibronectin. The aim of this thesis is to analyze the surfaces-proteins-cells relationship, and especially the properties of fibronectin adsorbed onto model surfaces and their influence on cell behavior. Different model supports (glass, OTS, polystyrene) are generated and characterized. Then, adsorption kinetics using various protein concentrations are followed, and the amount and the conformational changes of adsorbed fibronectin are concomitantly determined. Finally, cell adhesion and morphology are studied in different cell seeding conditions, and for two cell types
Saulière, Aude. "Etapes membranaires de la transduction du signal par les récepteurs couplés aux protéines G : organisation dynamique du récepteur mu aux opioïdes humain à la surface de neuroblastomes." Toulouse 3, 2007. http://www.theses.fr/2007TOU30121.
We address the question of the existence of a specific membrane organization which could favor the interactions between the G protein coupled receptor (GPCR), the G protein and the effector. Here we examine the lateral diffusion of the human mu opioid receptor (hMOR) in regard to its activation by ligands and to membrane environment modifications. The T7-EGFP-hMOR stably expressed in SH-SY5Y is found to be fully functional. Its mobility analysis was achieved using two complementary biophysical approaches which are vrFRAP (variable radii fluorescence recovery after photobleaching) and SPT (single particle tracking). At 22°C these analyses reveal a double compartimentation of the receptors in permeable domains (about 1 µm radius) and in smaller domains (200 nm radius). Moreover receptors exhibiting a directed diffusion are observed. The temperature was modulated, the actin cytoskeleton was partially destroyed, and the G protein/receptor interaction was impeded to determine the sources of the receptor organisation. It appears that many parameters are playing a part in the complex receptor organisation. Our results show that the interactions of hMOR with G proteins or with the cortical cytoskeleton influence its membrane organisation. Antagonists binding don't modify the receptor organisation in permeable sub-micrometer size domains. On the contrary agonists binding induce a decrease of both the domain size and the diffusion coefficient. Our results highlight the influence of numerous parameters on the hMOR dynamic organisation. They demonstrate the interest of a conjoint use of vrFRAP and SPT approaches to obtain a global vision of a protein plasma membrane organisation
Nehmé, Rony. "Expression et purification du récepteur humain de la voie Hedgehog, Smoothened, dans une conformation native et stable." Nice, 2009. http://www.theses.fr/2009NICE4031.
The Hedgehog pathway is one of the most important pathways in embryogenesis and in proliferation of adult stem cells. This pathway involves two transmembrane receptors, Patched and Smoothened whose dysfunctions have been linked to many human diseases including cancers. This study reports expression and purification of the human GPCR Smoothened, for structure-function relationship characterization. Therefore I developed the heterologous expression of Human Smoothened (hSmo) in the yeast S. Cerevisiae. Using SPR technology, I showed that hSmo, expressed at the plasma membrane of yeast, is in its native conformation able to bind its antagonist, cyclopamine (CPN). Then, I developed the purification of hSmo by affinity chromatography and tested new surfactants. Results show that the new surfactants stabilize hSmo in solution after purification and are preserve antagonist-binding ability of Smo suggesting that purified hSmo maintains its native conformation in solution. In addition, characterization of a single mutation of Smoothened (hSmoG435R) combined to one of the surfactants, revealed an enhanced stability of the receptor. These established conditions will be useful for crystallization assays. SPR strategies developed in this study will also be used for the research of hSmo’s cytoplasmic partners. Together, structural and functional data will contribute to the better understanding of Smo signaling and to the development of new cancer therapies
Allouche, Rania. "Effet anti-inflammatoire d’hydrolysats de protéines de surface ou intracellulaires de Streptococcus thermophilus obtenus après action de protéases digestives." Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0344.
Inflammation is a mechanism that provides protection against injury, trauma, or infection caused by damaged cells, irritants, or pathogens. This process removes harmful agents and damaged tissue components. Nevertheless, chronic low-grade inflammation is often associated with various pathologies. Diet could be a promising way of action. Indeed, bioactive peptides derived from the hydrolysis of dietary proteins could modulate key inflammatory factors and consequently delay the onset of these chronic diseases. Furthermore, lactic acid bacteria, components of fermented milk products, exhibit anti-inflammatory properties both in vitro and in vivo studies. Among them, Streptococcus thermophilus (ST) is regularly consumed by a significant part of the population. Studies have shown that some strains of ST display anti inflammatory activity in vitro with an unknown mechanism of action. In this work, it was hypothesized that peptides released after hydrolysis by digestive proteases of the surface or intracellular proteins of this bacterium could be involved at least partially in this activity. Firstly, hydrolysates were obtained by shaving surface proteins with trypsin or pepsin followed or not by trypsinolysis. The tandem mass spectrometry analysis indicated that the majority of the identified peptides belonged to the surface proteins of this bacterium. Secondly, the anti inflammatory activity of the hydrolysates was evaluated in two inflamed cell models. The hydrolysate obtained after tryptic shaving and trypsinolysis of surface proteins of ST LMD 9 significantly decreased the secretion of the pro-inflammatory cytokine IL 8 in lipopolysaccharide (LPS) stimulated HT 29 cells. The same hydrolysate also reduced production of IL 8 and of the pro-inflammatory cytokine IL 1β as well as protein expression levels of Pro IL 1β and COX 2 in LPS-stimulated THP 1 macrophages. It was proposed that the surface protease PrtS could be a source of active peptides during gastrointestinal digestion. To verify this hypothesis, hydrolysates were prepared by shaving with pepsin followed or not by trypsinolysis of the surface proteins of two phenotypically distinct strains of ST: LMD 9 (PrtS+) and CNRZ 21N (PrtS-). Modulation of pro-inflammatory mediators IL 8, IL 1β, Pro IL 1β and COX 2 was assessed in LPS-stimulated THP 1 macrophages and IL 8 in LPS stimulated HT 29 cells. The hydrolysates from the two strains showed an anti inflammatory action but modulation of all these inflammatory mediators was strain, hydrolysate, and concentration dependent. Interestingly, the strain lacking PrtS also showed anti-inflammatory activity. Therefore, peptides released from surface proteins of ST strains by proteases of the gastrointestinal tract during digestion of a product containing this bacterium could exert anti-inflammatory effects and thus could reduce the risk of inflammation related chronic diseases. Finally, the intracellular proteins of the LMD 9 and CNRZ 21N strains were recovered by sonication and hydrolysed with Corolase PP, a mixture of pancreatic proteases. Hydrolysates generated from a fraction of these proteins of both strains demonstrated anti inflammatory action by modulating some of the pro-inflammatory mediators in LPS stimulated THP 1 macrophages. To our knowledge, this is the first study demonstrating the anti inflammatory activity of peptides derived from surface proteins and a fraction of the intracellular proteins of ST strains. These paraprobiotics or postbiotics, likely to be released in the digestive tract of the consumer, could participate in the overall anti inflammatory effect of S. thermophilus which had been demonstrated with certain strains. They could display beneficial effects on human health and therefore could be a promising bioactive ingredient for the development of novel functional foods for the prevention of low grade inflammation
Jonquières, Renaud. "Association de la protéine InlB à la surface de Listeria monocytogènes : conséquences sur l'invasion de cellules eucaryotes non-phagocytaires." Paris 7, 2001. http://www.theses.fr/2001PA077090.
Hur, Sunyoung. "Molecular mechanism of barnacle adhesion : a structural approach and underlying biochemistry." Electronic Thesis or Diss., Sorbonne université, 2022. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2022SORUS572.pdf.
Barnacles adhere themselves robustly and permanently to diverse underwater substrates through strong interactions of a multi-protein complex layer called the “cement”. However, the intermolecular interactions responsible for the strong adhesive properties of the barnacle cement remains poorly understood. A central hypothesis of this thesis is that underwater properties of the cement complex are intimately linked to the molecular characteristics of cement proteins (CPs) forming the cement complex. Previous studies have shown that the cement is made of amyloid-like nanofibrils that may contribute to adhesion. However, the protein responsible for the formation of these nanofibrils remain unknown. In this study, the nanoscale morphological features of recombinant cement proteins (CPs) from the barnacle Megabalanus rosa (MrCP19 and MrCP20, with the numbers indicating molecular weight of 19 kDa and 20 kDa respectively) were characterized by Circular Dichroism (CD) measurement, Thioflavin T (ThT) assay, Atomic Force Microscopy (AFM), and Transmission Electron Microscopy (TEM), suggesting the potential to form nano-fibrillar structures under certain conditions. Based on the proteins’ primary structure and surface morphology, mechanical, biochemical, and antimicrobial studies were conducted to understand the unique roles of these interfacial proteins on barnacle growth and surface attachment process, for instance biomineralization and biodegradation control. Measurements using Surface Force Apparatus (SFA) and Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) illustrated that electrostatic interactions play a key role in surface adsorption and adhesion of MrCP19 and MrCP20. In addition, the mutual influence of barnacle base plate growth (calcium carbonate mineralization) and the adjacent cement protein MrCP20 fibrillation was investigated using self-assembled monolayer (SAM) functionalized gold surfaces, Raman spectroscopy, QCM-D, X-ray photoelectron spectrometer (XPS), and Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Concurrently, the influence of the external substrate adjacent cement protein MrCP19 on bacteria cells which are present in biofilm on underwater surfaces in marine environment was demonstrated using different microbiology tests including zone of inhibition test, Minimum inhibitory concentration (MIC) assay, TEM, fluorescence study, and so on. More interestingly, an intriguing hypothesis regarding amyloid fibrillation process and antimicrobial activity was suggested. Based on these preliminary examinations, the two interfacial CPs showed distinctive potential responsibilities on barnacle settlement not only with its adhesion but also with other functional roles at the interfaces. This work will improve our knowledge about individual contributions of MrCP19 and MrCP20 in cement complex and hence in overall underwater adhesion capacity of barnacles. In this regard, the thesis aims at providing molecular guidelines towards the development of CPs inspired polymeric (peptide or protein based) mimics from this bio-adhesive molecular system
Daumas, Frédéric. "Diffusion latérale du récepteur ư aux opioi͏̈des analysée par suivi de particule unique à la surface de cellules vivantes : relation organisation dynamique-fonction." Toulouse 3, 2002. http://www.theses.fr/2002TOU30180.
G protein coupled receptors are involved with other partners in a signal transduction pathway whose mechanism is still not completely understood. We used single particle tracking to study the real time lateral movements of the æ opioid receptor on the surface of fibroblast cells stably transfected by a T7-tagged æ opioid receptor. Two populations could be distinguished : 10% of the receptors exhibit a directed diffusion mode and 90% have a "walking confined diffusion" mode combining a short term confined diffusion with a long term random walk. .
Vincent, Patrick. "Trafic intracellulaire des phospholipides du système endomembranaire chez un végétal supérieur Allium porrum L. : étude de la relation synthèse-transport de la phosphatidylsérine à la surface cellulaire. Caractérisation chez ce végétal d'ADNc codant pour des protéines membres potentiels de la famille des SNAREs Ykt6p, impliquée dans le transport RE-Golgi." Bordeaux 2, 2000. http://www.theses.fr/2000BOR28816.
The work presented in this thesis concerns the study of the biogenesis of the plasma membrane in higher plants, on the model of Allium porrum. The plasma membrane of the eukaryotes is enriched in phosphatidylserine, where it plays a fundamental role in various biological activities, notably in the membrane traffic, allowing for exchanges in the extracellular environment. The studies carried out on the relationship between the synthesis and the transport of this phospholipid to the cellular surface, have demonstrated that there may be two different origins : vesicular, through the endoplasmic reticulum-Golgi apparatus pathway, and locally, by synthesis activity on the plasma membrane. Very long chain fatty acid species are sorted and directed in priority towards the secretion pathway. They are synthetized in the endoplasmic reticulum by a Base exchange activity, but also at the cellular surface with the same enzyme activity. In order to characterise vesicles which are rich in phosphatidylserine, formed and isolated from the endoplasmic reticulum in an cell-free system, studies have been carried out on the research of cDNA coding for proteins which are potentially members of Ykt6p SNAREs. In animals and yeast cells, this family is involved in the specific targeting of vesicles which come from the endoplasmic reticulum and which are to be used in the Golgi apparatus
Rouhana, Jad. "Etude et modulation des interactions protéine-protéine : l’activation de la petite protéine G Arf1 par son facteur d’échange Arno." Thesis, Montpellier 1, 2013. http://www.theses.fr/2013MON13507/document.
Arf1 is a small GTPases, essentially involved in the vesicular traffic. Arf1 switch between two conformations, an active form bound to GTP and an inactive form bound to GDP. Arno is one of the exchange factors (GEF) that can activate Arf1, through its catalytic Sec7 domain, promoting the exchange of GDP by GTP. Activated in breast cancer cells, Arf1 plays an important role in the migration and proliferation of cancer cells.The aim of my thesis was the study and the modulation of the interaction between small G proteins and their GEFs, more precisely the Arf1-Arno interaction. My work has been planned around two axes: (1) the study of the interaction between Arf1 and Arno, and its modulation with a known inhibitor Brefeldin A (BFA). (2) The development of a rational strategy for designing inhibitors of protein-protein interaction for the Arf1-Arno complex.In the first part of my PhD work, we set up a Surface Plasmon Resonance (SPR) method allowing to determine the kinetic parameters of the interaction between Arf1 and Arno. We also studied the effects of allosteric partners such as GDP, GTP and Mg2+ as well as the known uncompetitive inhibitor (Brefeldin A). This SPR approach allowed a very informative analysis at qualitative and quantitative levels of the various complexes taking place during the exchange reaction that should help to solve the inhibitory mechanism for the known inhibitors reported in the literature. In the second part of my thesis, we propose a strategy for targeting the interaction between Arf1and Arno. This approach is based on virtual screening of fragments at hotspot regions. Using biophysical techniques such fluorescence techniques, SPR, NMR and X-Ray crystallography, we identified and validated Hits, showing by crystallographic structural data their modes of interaction with the target protein Arno. A fluorescence polarization test was also developed to identify false positive fragments to eliminate promiscuous aggregators. Taken together, our work proposes a method based on SPR allowing the study of known inhibitors of GEFs, understanding at molecular level their mode of action. We also propose a general strategy for finding Hit fragments that designing competitive inhibitor of the interaction small G protein with its GEFs, that can be the scaffold for designing more powerful inhibitors
Thakar, Dhruv. "Surfaces biomimétiques pour caractériser les interactions induites par les glycosaminoglycanes aux niveaux moléculaire, supramoléculaire et cellulaire." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAV005/document.
The oriented migration and controlled adhesion of cells is fundamental to many physiological and pathological processes. A family of linear polysaccharides, known as glycosaminoglycans (GAGs), help organizing and presenting signaling proteins, so-called chemokines, on the cell surface and in the extracellular matrix thus regulating cellular behavior. The objective of this PhD thesis was to develop biomimetic surfaces that are highly defined and tunable, for mechanistic studies of GAG-protein interactions on the molecular and supramolecular levels, and to probe cellular responses to defined biochemical and biophysical cues to better understand GAG-mediated cell-cell and cell-matrix communications.Applying oxime ligation, GAGs could be stably functionalized with biotin at the reducing end, and these features proved crucial for the reliable preparation of GAG-functionalized surfaces. A streptavidin monolayer served as a ‘molecular breadboard' to sequentially assemble biotinylated molecules with controlled orientation and surface densities. GAGs (heparan sulfate (HS) in particular), chemokines and other ECM components (e.g. integrin ligands promoting cell adhesion, RGD) were assembled into multifunctional surfaces that recapitulate selected aspects of the in vivo situation. Quartz crystal microbalance (QCM-D) and spectroscopic ellipsometry permitted us to characterize and control the supramolecular presentation of HS and RGD. These model surfaces were used to study the supramolecular interactions between HS and the selected chemokine stromal derived factor SDF-1α/CXCL12α and to analyze cellular responses to extracellular cues. Our data provide evidence that CXCL12α binding rigidifies HS assemblies, and that this effect is due to protein-mediated cross-linking of HS chains. The kinetics of chemokine binding to HS was quantified using surface plasmon resonance (SPR). We also demonstrate that the way in which the chemokine is presented, and in particular the presence of HS, is important for regulating myoblast behavior. Our data shows that the cell surface receptors CXCR4 (the CXCL12α receptor) and integrins (the RGD receptor) can act synergistically in controlling cellular adhesion and migration. These surfaces can generate novel insights in the field of glycobiology, e.g. in dissecting the function of GAGs in chemokine-mediated cellular migration
Rascol, Estelle. "Etude des propriétés de surface de nanoparticules à l’interface avec les fluides biologiques et les membranes cellulaires." Thesis, Montpellier, 2016. http://www.theses.fr/2016MONT3516/document.
This work is a part of a multidisciplinary project focused on the safety of nanoparticles (NPs) developed for theranostic applications. The goal of this thesis is to investigate the role of surface chemistry of NPs at the biological interface. Two types of core-shell NPs have been studied: spherical mesoporous silica Fe3O4@MSN, with a diameter of 100 nm and a magnetic core, and cubic, cuboid and polyhedral NPs composed of Prussian blue analogous, presenting sizes comprised between 47 and 67 nm. The polyhedral Prussian blue NPs Au@BP contain a gold core. The NPs present different sizes, shapes and chemical compositions. Mesoporous silica NPs (MSN), particularly studied for their potential medical applications, have been used to evidence the relevance of model membranes to investigate NPs safety. First, Fe3O4@MSN were homogeneously synthesized, in reproducible 100 mg batches. These NPs have been functionalized by PEG grafting and lipid coating. The influence of the surface properties on the NPs stability have been characterized in various media. A human hepatocarcinoma cell line HepG2 have been used to measure the cell viability and observe the uptake kinetics when the cells are incubated with Fe3O4@MSN. To rely the surface properties of the NPs to their cell effects, the interaction of NPs with membrane models have been studied. Quartz crystal microbalance with dissipation monitoring (QCM-D) and surface plasmon resonance (RPS) were used to follow NPs-model membrane interactions. Functionalized NPs were uptaken faster than the bare ones, in particular lipid coated NPs, but were less cytotoxic for HepG2 cells. The presence of fetal calf serum proteins reduces the interaction of bare Fe3O4@MSN with model membranes, due to the protein corona that formed around the NPs. However, the presence of proteins doesn’t change NPs-model membranes interactions when NPs are functionalized by PEG grafting or coated with a lipid bilayer. The PEG groups and the lipid bilayers constitute a steric barrier which reduces the protein adhesion at the NPs surfaces. On the other hand, Prussian blue analogous NPs were also coated with lipid bilayers. The golden core of the polyhedral one’s confers localized plasmon properties. The lipid bilayer coating is equally performed on spherical, cubic, cuboid or polyhedral shapes of the various NPs. These different NPs are aggregated in high ionic strength conditions, with 150 mM NaCl, but dispersed when coated by lipid bilayer. The influence of the shape on the safety of the NPs may be compared, using these NPs with common surface coating but various shapes
Bacart, Johan. "Oligomérisation des récepteurs à la leptine." Lille 2, 2010. http://www.theses.fr/2010LIL2S013.
Leptin also called the satiety hormone is mainly produced by adipose tissue and regulate energy balance via the activation of its receptor (OB-R). In human, four isoforms of OB-R are produced by alternative splicing of a unique gene (OB-Ra, b, c, and d). These receptors share the same extracellular and transmembrane domain but have distinct cytoplasmic tails. While the long isoform OB-Rb, plays an essential role in obesity by regulating key signaling pathways implicated in lipid homeostasis, short isoforms (OB-Ra, c, d) functions are still unclear. Co expression of OB-Ra with OB-Rb in key tissue for regulation of obesity, and the shared extracellular and transmembrane domain between the different isoforms, allow us to investigate physical interaction between OB-R isoforms. It is well established that the shared extracellular domain of OB-R isoforms constitutively forms homodimers even in their soluble form. However, interactions between shorts and longs isoforms have not been clearly demonstrated and remain controversial. We have tried to demonstrate these interactions using the BRET (Bioluminescence Resonance Energy Transfer) technology. This method based on a Förster resonance energy transfer between an energy donor and an energy acceptor allows the monitoring of protein-protein interaction in living cells. Our results clearly demonstrate that the different OB-R isoforms homodimerize but also that shorts forms constitutively interact with OB-Rb in living cells. These are weak interactions, indeed disrupted when proteins are solubilized using similar experimental conditions used in co-immunoprécipitation of membrane receptor. The lack of evidence of these interactions in previous reports may then results from chosen methods and most particularly by the involved solubilization step. Unlike homodimers that are present in intracellular membrane and at the cell surface, shorts and longs isoforms are monitored only at the cell surface where they respond to leptin stimulation. This suggests that these complexes are only able to form at the plasma membrane and should have a functional role in signaling. Hence, our results suggest that OB-R isoforms form homodimers during biosynthesis, reach the cell surface where OB-R homodimers cluster in complexes. Leptin stimulation could lead to a conformational change in constitutive homodimers as previously shown, but also to a recruitment of preformed dimers in tetrameric complexes including some short and long isoforms dimers. To conclude, these OB-R heterodimers imply a critic discussion of published datas and may open new perspectives on the real impact of short and long OB-T isoforms on obesity
Cordier, Baptiste. "Compréhension des processus cellulaires associés à l' enveloppe de Bacillus subtilis : GluP, une protéase intramembranaire impliquée dans la dégradation des protéines membranaires & CmmB, un cofacteur de la synthèse de la paroi bactérienne." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4006.
The bacterial cell envelope is an obligatory barrier. It is a fundamental component in essential cellular processes such as morphogenesis and cell division. It hosts about a quarter of the proteins encoded in the genome. My work was aimed at understanding the function of two membrane proteins in the building and the dynamics of the cell envelope in the model bacterium Bacillus subtilis.GluP is a rhomboid intramembrane protease. Usually, rhomboids cleave transmembrane segments within the membrane to modulate protein functions. In eukaryotes, they participate in many cellular processes and their dysfunction lead to several pathologies. However, prokaryotic rhomboid functions remain almost totally unknown. Our results suggest that GluP is involved in bacterial membrane protein quality control, in a process akin to pseudo-rhomboid dependent endoplasmic reticulum associated protein degradation in eukaryotes. GluP forms a complex with FtsH, a major protease in protein quality control. That complex is not involved in the cleavage of a membrane substrate but in its degradation. We propose that GluP is required for the dislocation of the transmembrane segment, thus facilitating full-length substrate degradation by FtsH in the cytoplasm. My thesis second objective was to understand the role of the CmmB protein in morphogenesis. The absence of CmmB leads to slightly enlarged cells. CmmB seems to belong to the peptidoglycan synthesis machinery for cell-wall elongation. Our data support the idea that it is required for the proper activity of one or several penicillin-binding proteins (PBPs). In particular, we propose that CmmB is a cofactor of the PBP2a transpeptidase
Zoccola, Didier. "Étude des molécules de surface du lymphocte T impliquées dans les phénomènes d'adhésion cellulaire : étude des relations structure-fonction de la molécule E2." Nice, 1993. http://www.theses.fr/1993NICE4698.
Demanga, Galamo Corine Josiane. "Analyse méthodique d'une nouvelle famille de protéines de Plasmodium falciparum en vue de la définition de constructions vaccinales polyantigéniques anti-paludiques." Paris 6, 2009. http://www.theses.fr/2009PA066157.
Cantaloube, Jean-François. "Etudes immunologiques et génétiques du récepteur du C3d et du virus d'Epstein-Barr, l'antigène CD21." Montpellier 2, 1990. http://www.theses.fr/1990MON20066.
Terrasse, Rémi. "La glycéraldéhyde-3-phosphate déshydrogénase, une protéine de la glycolyse présente à la surface cellulaire, est impliquée dans la reconnaissance par le système du complément chez Streptococcus pneumoniae." Thesis, Grenoble, 2013. http://www.theses.fr/2013GRENV061/document.
Streptococcus pneumoniae is a major human pathogen, which causes pneumonia, meningitis and septicemia. To insure its survival and dissemination, the pneumococcus deploys an array of virulence factors promoting invasion of tissues and evasion from the immune system. A particular class of proteins not associated with any known export system, the moonlighting proteins, is found at the pneumococcal surface. Moonlighting proteins are conserved cytoplasmic metabolic enzymes or molecular chaperones localized in various cellular compartments and exhibiting additional functions. The glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is found at the surface of numerous eukaryotic and prokaryotic cells, and display diverse roles in the virulence processes of pathogenic organisms. The pneumococcal surface GAPDH acts as a virulence factor by binding to host plasminogen/plasmin, which facilitates the bacterial invasion through the extracellular matrix and the endothelial and epithelial cell barriers. However, the mechanisms leading to the GAPDH export and binding to the bacterial surface had not been deciphered yet. This work demonstrates that the GAPDH is released upon cell lysis and associates with the peptidoglycan. C1q, a key component of the classical complement pathway, is a major player in the response to microbial infection and has been shown to detect noxious altered-self substances such as apoptotic cells. The use of complementary experimental approaches allowed the identification of the GAPDH as a C1q partner when exposed at the surface of S. pneumoniae and human apoptotic cells. However, and rather unexpectedly, the pneumococcal GAPDH activates the complement cascade unlike the human one. Those results encourage further studies in order to understand how C1q recognition of two closely related proteins can lead to such striking differences on its complement activation properties
Six, Anne. "Caractérisation moléculaire et fonctionnelle de la protéine Srr2 et rôle dans l’hypervirulence du clone ST-17 de Streptococcus agalactiae." Thesis, Paris 5, 2013. http://www.theses.fr/2013PA05T038.
Streptococcus agalactiae is the leading cause of invasive infections in neonates. Despite the implementation of prevention strategies, this bacterium remains the main etiological agent of neonatal infections. Hyper-virulent sequence-type 17 strains are particularly associated with meningitis, a type of infection with serious consequences in terms of mortality and morbidity. This clone has unique characteristics, such as fibrinogen binding, and a panel of specific surface proteins. Among these proteins, Srr2 belongs to a family of large streptococcal and staphylococcal glycoproteins involved in pathogenicity. A central domain of Srr2, BR domain, is responsible for the specific binding of fibrinogen by the ST -17 clone and also binds plasminogen and various components of the extracellular matrix. Thereby, it promotes adhesion and crossing of cellular barriers. The interaction of Srr2 with fibrinolytic and coagulation systems of the host could promote bacterial spread through the activation of fibrinolysis and the persistence of the bacteria in the host by the formation of bacterial aggregates. The interaction of Srr2 with fibrinogen also seems to promote bacterial persistence in promoting the internalization and survival of the bacteria in macrophages. Thus, Srr2 confers an advantage to the infectious process of the ST- 17 clone in the host and is an attractive vaccine candidate for the prevention of S. agalactiae infections
Trabelsi, Noureddine. "Évaluation de la lignée myélomonocytaire U-937 comme modèle d'étude de la réponse du macrophage alvéolaire aux particules minérales : application à l'étude de l'effet des particules minérales sur les récepteurs de surface et la glycosylation des protéines." Paris 12, 1997. http://www.theses.fr/1997PA120090.
Soumbo, Marvine. "Adsorption des protéines sur les surfaces de couches minces de silice seules ou additivées de nanoparticules d'argent : impact sur les forces d'adhésion de Candida albicans." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30258.
Microbial adhesion on solid surfaces is the source of multiple negative impacts in many areas. This step is considered prior to biofilm formation. It might be influenced by the presence of a conditioning layer generated after protein adsorption on the surface. Thus, strategies to act during the initial phase of microbial adhesion represent an appropriate approach to prevent bio-contamination of solid surfaces. However, they require understanding of the underlying mechanisms at the molecular level. In this context, nanocomposite materials based on silver nanoparticles (AgNPs) and silica (SiO2) appear as relevant tools. This thesis focuses on the use of nanocomposite thin layers containing a plan of AgNPs exposed on their surfaces or buried in a SiO2plasma matrix at a controlled distance of a few nanometers from the surface in order to explore, on the one hand, the adhesion of model proteins (Bovine Serum Albumin, DsRed and Fibronectin) and their conformational changes and secondly, the kinetics of detachment of the yeast Candida albicans under the different conditions. AgNPs are well known for their antimicrobial activities but also for their optical properties allowing detection of molecular signatures at their proximities. Following the application of surface-enhanced Raman spectroscopy using AgNP-based nanocomposite layers, the detection of three conformations of DsRed (red fluorescent protein) adsorbed and dehydrated on plasmonic substrates was achieved. The obtained results show that the conformational changes of proteins with a strong internal coherence are reversible. In parallel, we have evaluated the dynamics of the organization and behavior of BSA, Fn and DsRed in contact with thin silica layers or silica layers containing AgNPs. Contact angle measurements of droplets of different protein concentrations showed increasing hydrophilic interaction with thermal SiO2th. For the nanocomposite layers, the surface hydrophobicity is modified. The thickness and optical properties of the adsorbed protein layers were evaluated by spectroscopic ellipsometry. Depending on the protein concentration in solution the results show the evolution of a non-continuous and non-dense protein monolayer to a more compact and complex monolayer at high concentrations. [...]
Longo, Johan. "Design of biomechanocatalytic surfaces : modulations of enzymatic activity through macromolecular conformational changes." Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAE022/document.
Since many years, a new generation of materials called « smart materials » and defined by their capacity to adapt to their environment is intensively developed. Systems sensitive to different stimuli such as pH, light or ionic strength have been reported. One of these stimuli can also be a mechanical force which is involved in many reactions in nature such as, cells adhesion and proliferation, tissues growing or even plants developments. The aim of my thesis was dedicated to the elaboration of mechano-responsive materials. More precisely, materials that transform a stretching constraint into a chemical signal by mimicking the physical processes used by nature, namely protein conformational changes. We planned to achieve this goal by covalently grafting proteins or enzymes onto a stretchable substrate or incorporating them into cross-linked polymer networks. Stretching these materials should induce protein conformational changes leading to modifications of their properties
Hattar, Susan. "Concept de surfaces biomimétiques pour stimuler in vitro l'ostéogenèse." Paris 7, 2004. http://www.theses.fr/2004PA07A001.
Rey, Isabelle. "Contrôle de l'activité cellulaire des protéines p21 ras par des protéines régulatrices." Paris 6, 1990. http://www.theses.fr/1990PA066667.
Mehlen, Patrick. "Les petites protéines de stress : des protéines qui contrôlent la mort cellulaire." Lyon 1, 1995. http://www.theses.fr/1995LYO10275.
Velzenberger, Elodie. "Validations biologiques et physico-chimiques d'un revêtement cellulosique de boîtes pour cultures cellulaires bioactives." Compiègne, 2008. http://www.theses.fr/2008COMP1784.
Surface properties of biomaterials may influence protein adsorption and the composition of the protein layer may affect the morphology and the functional orientations of adherent cells. In this work, both biological and physico-chemical approaches were combined to characterize an original cellulosic coating (CEL) for cell culture and to better understand the interactions involved between a surface, proteins and finally cells. The aim of this multi-disciplinary project is to correlate surface properties (at the micrometric and at the nanometric scale) with biological activations. Three adherent murine cell lines were chosen (fibroblasts Swiss 3T3, pre-osteoblasts MC-3T3 and melanoma cells B16F10). Liquid-liquid contact angle measurements and AFM enabled to characterize the physico-chemical properties of the cellulosic substratum before and after fibronectin adsorption. The principal results obtained with the cellulosic substratum are summerized below : Cell aggregation; A cellular proliferation inhibition with a blocking in G1-phase; An induction of apoptosis; CEL is hydrophilic and a little amount of fibronectin is adsorbed on the substratum in a conformation which is not appropriate for cell adhesion (bad accessibility to RGD site); Instantaneous affinity negligible of fibronectin for the cellulosic material. This study evidences that CEL is an anti-adhesive biomaterial which gives reproducible and demonstrative results. Moreover, this work underlines the necessity to combine several approaches (ELISA assays, liquid-liquid contact angle measurements, force spectroscopy) to characterize the interaction between a protein and a biomaterial surface under physiological conditions
Charpentier, Nathalie. "Les protéines Go de transduction, étude cellulaire et moléculaire." Montpellier 2, 1993. http://www.theses.fr/1993MON20196.
Dalkara, Deniz. "Transfert intracellulaire de protéines." Université Louis Pasteur (Strasbourg) (1971-2008), 2006. http://www.theses.fr/2006STR13021.
During this thesis we have developped an efficient method for intracytoplasmic protein delivery into mammalian cells. This method employs cationic lipids, previously used in gene delivery, to complex proteins and to transport them into the cytoplasm of cells in culture. In the last decade, the most commonly used approach for protein expression has been the transfection of its gene. Considering that the aim of transfection is to produce proteins and that synthetic vectors are capable of efficient gene delivery to mammalian cells ; we studied direct intracellular protein delivery using these carriers. The direct delivery of functionally active proteins can be helpful in overcoming some bottlenecks of transfection mediated protein production. We thus initiated studying intracellular protein delivery using the cationic lipid DOGS. We studied the interaction of the cationic lipid with bovine serum albumin and determined the different parameters involved in creating complexes that are well internalised by cells. We applied the notions acquired during the intracellular delivery of this model protein to a variety of other proteins with different physico-chemical properties in order to apprehend the contribution of these properties to the processus of complexation and vectorisation by DOGS. We successfully delivered a variety of proteins such as monoclonal antibodies, an enzyme, and a phycobilliprotein into different mammalian cell lines. Furthermore, we demonstrated that the antibodies delivered using this method retain their ability to bind their antigens once they reach the cytoplasm. From this point of view, intracellular protein delivery with cationic lipids can be considered another way to interfere with cellular activities. During this thesis, we have thus developped an original strategy for the intracellular delivery of proteins which will allow us to deliver, in vivo, a large variety of proteins for therapeutic purposes or functional studies
Gavard, Olivia. "Modélisation et analyse de l'interactome de la kinase humaine Aurora A." Doctoral thesis, Université Laval, 2016. http://hdl.handle.net/20.500.11794/26685.
The serine-threonine kinase Aurora A is an essential mitotic cell cycle protein. Aurora A is necessary for mitotic entry and for the maturation and separation of centrosomes. It participates in mitotic spindle assembly and chromosome biorientation, and it is essential for the completion of cytokinesis. Furthermore, Aurora A activity is necessary for the equal distribution of mitochondria to daughter cells and, through its role in the alternative splicing of mRNA of apoptotic factors, it provides a link between cell cycle control and apoptosis. Beyond its mitotic functions, several recent studies suggest that Aurora A is also important during interphase. Notably, it influences microtubule dynamics, promotes cell migration and polarity control and is essential for primary cilia disassembly. Reflecting the fact that Aurora A is found to be up-regulated in many cancers, deregulation of Aurora A activity can result in an aberrant cell cycle, ultimately leading to malignant transformation of cells. The crucial regulation of Aurora A’s numerous functions is achieved through its interaction with several protein partners, which modulate its activity, localisation and stability. Aurora A in turn phosporylates a number of them, thus regulating their activity, localisation and stability. However, the known interactions of Aurora A cannot explain all the phenotypes that have been described of its deregulation. To better understand the functions of Aurora A, the regulation mechanisms governing it, and to expose its multiple roles in the cell, I have built and analysed an Aurora A interactome using tandem affinity purification coupled with mass spectrometry. This resulted in the identification of 477 potential interacting partners, of which, 180 were determined to have a high probability of interacting directly with the kinase. In-depth bioinformatic analysis of this interactome has revealed the associated partners to be related to mitochondria and mRNA splicing, highlighting the potential involvement of Aurora A in these mechanisms. To validate the interactome, two of the proteins identified in this study, WDR62 and CEP97, were examined in detail. Here I show that these two proteins colocalise with Aurora A, and are phosphorylated by the kinase. WDR62 is implicated in microcephaly and is deregulated in certain cancers. I have shown that Aurora A phosphorylates WDR62 during mitosis, and that this phosphorylation is necessary for its localisation to the centrosomes. CEP97 is a poorly charactarised protein of the primary cilium, abnormalities of which are associated with ciliopathies. I have shown that Aurora A phosphorylates CEP97 in vitro, and that the inhibition of Aurora A activity in vivo perturbs the localisation of CEP97 to cilia and centrosomes. This study has identified a number of new Aurora A-interacting proteins, implicating the kinase with novel functions. These functions, related to mitochondria and mRNA splicing have opened up a new area for further investigation.
Sergeeva, Yulia. "Complexes ADN/polycation en solution et aux interfaces en tant que vecteurs de transfection non viraux de pointe." Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-01064224.
Boucher, Julie. "Glycation des protéines intracellulaires : impact sur la fonction contractile cellulaire." Thèse, Université de Sherbrooke, 2015. http://hdl.handle.net/11143/6847.
Igel, Angélique. "Mécanismes d'inactivation des protéines amyloïdes." Paris 7, 2013. http://www.theses.fr/2013PA077101.
Amyloides fibers correspond to insoluble protein assemblies associated to the neurodegenerative diseases. By taking into account properties biophysics of these fibers which confer them a very high resistance, and the spectre of their transmissibility, everything lets suggest that medical surgical acts could potentially lead or transmit amyloidoses by the inoculation of nucleation seed. The objective of this work is to estimate mechanisms of inactivation of A ß and prion assemblies, to understand the mechanisms of inactivation of amyloides proteins. At first, we estimated the evolution of the quaternary structure of the assemblies of prion stemming from 3 strains (263K, vCJD and 139A) after decontamination treatments. Ail results demonstrate that the inactivation of prion are strain dependent. This intrinsic property of strain would be due to different structuring of PrP protomers within the assemblies. Finally, similar approaches to those used on the field of prions were used to estimate the résistance of amyloide assemblies stemming from the Alzheimer's disease (peptide A ß). Our preliminary results of synthetic peptide A ß inactivation, show that this peptide, in its fibrillar state, possesses properties conferring it a high strength. To deepenour results in a model of peptide having sudden a maturation of in-vivo withdrawal, we have designed a new cellular model expressing the peptide A640. This new tool is operational recently and seems promising for the study of the properties of the peptide Aß
Navarro, Christel. "HScrib : protéine clé de la polarité cellulaire." Aix-Marseille 2, 2005. http://www.theses.fr/2005AIX20655.
Scribble is a LAP protein, characterized as tumor suppressor in Drosophila. We have shown that the LRRs of human Scribble (hScrib) are essential for its subcellular localization. Moreover, this membrane recruitment is depending on E-cadherin engagement. We provide evidences that in vertebrates, hScrib is probably not involved in apico-basal polarity. In order to identify its functions, we have isolated some protein partners of hScrib, which are ZO-2, bPIX/GIT1 and TSHR. All of them interact with the PDZ domains of hScrib. The ZO-2/hScrib's functions are still unitentified. The hScrib/bPIX complex is involved in regulated exocytosis and in neuronal transmission. Moreover, this complexe mediates vesicular recycling of TSHR. These new functions associated with the role of hScrib in planar cell polarity led us to consider hScrib as a key protein of cell polarity
Berthier, Alexandre. "Développement d'outils « biocapteurs/modèle cellulaire » pour l'identification de ligands et l'étude des interactions ADN/protéine et protéines/protéines." Phd thesis, Université de Franche-Comté, 2008. http://tel.archives-ouvertes.fr/tel-00404562.
Berthier, Alexandre. "Développement d’outils « biocapteurs/modèle cellulaire » pour l’identification de ligands et l’étude des interactions ADN/protéine et protéines/protéines." Besançon, 2008. http://www.theses.fr/2008BESA2054.
Estrogens could modulate gene expression by interacting with Estrogens Receptors (ER). These receptors were described as transcription factor and are able to interact with a specific DNA sequence called Estrogens Response Element (ERE). The screening of molecules able to link to ER and to modulate gene expression could be applied to new therapeutic developments (menopauses, hormonodependant cancers) or could have an impact on healthcare and environment protection (endocrine disturbers). We have designed two Surface Plasmons Resonance (SPR) biosensors to develop a fast and low cost molecular screening strategy. In order to validate the routine application of these tools, SPR results must be correlated with more classical data obtained with a cellular model. That was why we have transfected a human breast cancer cell line (MCF-7) with a reporter vector. We have identified a new ERα agonist phytoestrogene (7-O-β-D-glucopyranolychrysin) using this double approach. Furthermore, one of ours biosensors was also applicable to the proteins/proteins interactions detection. We have decided to use this sensor to identify new partners of GEC1 protein. In conclusion, we have designed in parallel DNA/protein biosensors and cellular model in order to identify xenoestrogen (7-O-β-D-glucopyranolychrysin). We have also developed a proteins/proteins biosensor which was consistent with protein partner identification
Berthet, Cyril. "Études des relations des protéines BTG-APRO avec leurs partenaires CAF1 et PRMT1." Lyon 1, 2001. http://www.theses.fr/2001LYO1T231.
Dubois, Marie-Line. "Implication des protéines MCM dans la réponse cellulaire aux dommages à l’ADN." Mémoire, Université de Sherbrooke, 2015. http://hdl.handle.net/11143/9568.
Baudot, Anaïs. "Analyse bioinformatique des interactomes : une approche de la fonction cellulaire des protéines." Aix-Marseille 2, 2007. http://www.theses.fr/2007AIX22021.
Organism cell functioning mainly depends on physical interactions, more particularly between proteins. These protein-protein interactions form complex intricate networks in the cell. The aim of my PhD work was first to automatize the PRODISTIN method, developped in the lab in order to extract biological information from interaction networks, and to expand it to weighted networks. Second, the method has been applied to study paralogous genes, remnant of yeast whole genome duplication. It permitted to propose a functional scale of divergence for duplicated genes based on the analysis of protein-protein interactions. Third, we made a global analysis of 9 signaling pathways integrated in the drosophila interactome. We identified a modular signaling network lying centrally in the interactome and predicted a signaling function for certain proteins of yet unknown function. We are currently working on a local analysis of Pi3K signaling pathway integrated in human interactome
Bérubé, Julie. "Influence de l'environnement cellulaire sur l'activité des protéines antirétrovirales TRIM5α et TRIMCyp." Thèse, Université du Québec à Trois-Rivières, 2011. http://depot-e.uqtr.ca/2264/1/030276729.pdf.
Delpech, Floriane. "Dynamique cellulaire des protéines de la réplication chez l'archée halophile Haloferax volcanii." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLX087/document.
The aim of this thesis project was to improve our understanding of DNA replication in archaea, the third domain of life with bacteria and eukarya. The model organism chosen for these studies is the halophilic archaea Haloferax volcanii, a mesophilic aerobe for which genetics tools allow studying in living cells the localization of proteins fused to the Green Fluorescent protein (GFP). Four proteins involved in DNA replication were fused to the GFP and expressed under the control of their own promoter: (i) the ‘Flap Endonuclease 1’ (FEN1), involved in Okazaki fragments maturation, (ii) the ‘Origin Recognition Complex’ (ORC1), involved in DNA replication origin recognition, (iii) the ‘Proliferating Cellular Nuclear Antigen’ (PCNA), processivity factor of replicative DNA polymerases, and (iv) the ‘Replication Protein A’ (RPA2), single-stranded DNA binding protein essential for DNA replication in H. volcanii. Only the PCNA fusion to the GFP was not successful, suggesting that the GFP hinders essential roles of PCNA in DNA replication. Fen1 and Orc1 were successfully fused to the GFP and expressed in living cells, but specific localization in cells related to growth phase, reflecting different replication dynamics, were not observed. In contrast, we could observed fluorescent foci formed by the fully functional GFP::Rpa2 protein that actively responded to DNA damage in H. volcanii cells. The number of these fluorescent foci per cell was constant during cell growth but it significantly increased in cells exposed to aphidicoline, which inhibits DNA synthesis during replication. When cells were treated with phleomycine, a DNA damaging agent mainly causing double-strand breaks, formation of a massive fluorescent focus coinciding with DNA compaction was observed. Our results suggest that the specific cellular localization of GFP::Rpa2 observed reflects Rpa2 roles in DNA repair and/or DNA replication fork restart
Rannou, Yoann. "Contrôle de la division cellulaire par les protéines kinases Mnk1 et Aurora." Rennes 1, 2008. http://www.theses.fr/2008REN1S123.
During mitosis two genetically identical daughter cells are generating. Mitosis is tightly controlled by various proteins like kinases in order to avoid errors which can lead to chromosomal instability. The aim of my PhD was to identify new kinases involved in mitosis control. I have identified the Mnk1 kinase which allows cell abscission by recruiting the centriolin at the midbody. I have also showed that the N-terminal domain of Aurora-A kinase regulates its localization at centrosomes, whereas Aurora-B N-terminal domain facilitates its nuclear localization. Finally I have described a new Aurora-A function. This kinase phosphorylates the Numb protein, a cell fate determinant involved asymmetric division. Numb phosphorylation by Aurora-A could control its localization and/or its endocytic activity
Chinchilla, Delphine. "Le rôle des ankyrine protéines kinases dans le développement végétal." Paris 11, 2003. http://www.theses.fr/2003PA112067.
Protein kinases are key components of signalling pathways. The Msapk1 gene (for Medicago saliva ankyrin protein kinase), coding for a novel protein kinase, was isolated as expressed in spontaneous nodules in alfalfa. This kinase has an unique aminoterminal domain containing three ankyrin repeats. This structure resembles that from animal Integrin Linked Kinases which are involved in cell adhesion in mammalian cells. The major objective of this work was to characterize the APK gene in Medicago spp. And their homologues in Arabidopsis thaliana, in order to understand their function in plant development. Msapkl expression was round to be induced upon hyperosmotic stress in Medicago roots. Moreover, a MsAPK1-GFP fusion protein localized to a cytoskeletal network after an osmotic shock in onion cells. By heterologous expression in E. Coli, we also showed that MsAPK1 phosphorylates tubulin in vitro. These results suggest that MsAPK1 may regulate cytoskeleton modifications occurring during cellular responses to osmotic stress in plants. In Arabidopsis, the AtAPK genes, homologues of Msapk1, were round to be differentially expressed in several organs. Despite the high conservation between Arabidopsis and Medicago truncatula genes, the AtAPKs seem not to be involved in osmotic responses in this species. Reverse genetics approaches on APK, developed to create "loss of function" and "gain of function" effects, suggest that APK genes are functionally redundant in Arabidopsis. In parallel, we characterized the induction of a CDPK gene expression, called MsCPK3, during nodule development in alfalfa. This activation takes place concomitantly with the induction of CDPK activity in alfalfa roots, during the early steps of nodulation. This CDPK is a potential target for calcium action in Fabaceae. These results add to the characterization of new protein kinases in Medicago spp. Involved in osmotic stress responses and nodule organogenesis. Moreover, the studies on APK may open new perspectives on their participation in plant cell adhesion processes