Дисертації з теми "Lipid signal"
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Frangioudakis, Georgia St Vincent's Clinical School UNSW. "Insulin signal transduction in vivo in states of lipid-induced insulin resistance." Awarded by:University of New South Wales. St Vincent's Clinical School, 2004. http://handle.unsw.edu.au/1959.4/27419.
Pott, Markus Philipp. "Organic hydroperoxide-induced lipid peroxidation (LPO) and signal transduction pathways in human keratinocytes." [S.l.] : [s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=96545293X.
FEZZA, FILOMENA. "Regulation of endocannabinoid system by lipid rafts along the neuroimmune axis." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2006. http://hdl.handle.net/2108/202611.
Anandamide (arachidonoylethanolamide, AEA) and the other endocannabinoid 2-arachidonoylglycerol (2-AG) bind to and activate two G protein-coupled receptors (GPCR), namely type-1 (CB1R) and type-2 (CB2R) cannabinoid receptors. CB1R are localized mainly in the central nervous system, but are also expressed in peripheral tissues like immune cells. Conversely CB2R are predominantly expressed peripherally, but they are also present in the brain. Therefore, activation of CB1 or CB2 receptors by AEA or 2-AG has many central and peripheral effects. These actions are controlled through not yet fully characterized cellular mechanisms, that regulate the release of endocannabinoids from membrane precursors, their uptake by cells, and finally their intracellular disposal. The key agent in AEA synthesis is the N-acylphosphatidylethanolamines (NAPE)-hydrolyzing phospholipase D (NAPE-PLD), whereas degradation occurs through an AEA membrane transporter (AMT), and a fatty acid amide hydrolase (FAAH). Besides CB receptors, AEA binds also to type 1 vanilloid receptors (now called transient receptor potential channel vanilloid receptor subunit 1, TRPV1). On the other hand, 2-AG is released from membrane lipids by means of a sn-1-specific diacylglycerol lipase (DAGL), and is hydrolyzed by a specific monoacylglycerol lipase (MAGL). The transport of 2-AG through the cellular membrane has been shown to be saturable and energyindependent, and might occur through the same AMT that transports AEA. Altogether AEA and 2-AG, with other congeners, the proteins that bind, transport, synthesize and hydrolyze these lipids, form the “endocannabinoid system”. Lipid rafts are subdomains of the plasma membrane that contain high concentrations of cholesterol and glycosphingolipids, and are well-known modulators of the activity of a number of GPCR. In fact, they modulate signaling and membrane trafficking in many cell types. The growing evidence suggesting that lipid rafts might modulate the endocannabinoid signaling prompted us to investigate also the possible effect of lipid rafts integrity on CB receptors, on AEA metabolism in neuronal and immune cells and on the proteins that synthesize, transport and degrade 2-AG. We have used the methyl--cyclodextrin (MCD), a membrane cholesterol depletor that is widely used to disrupt the integrity of lipid rafts. We have chosen rat C6 glioma cells, because they have a well characterized endocannabinoid system. We extended the study to human CHP100 neuroblastoma cells, which have the same ability as C6 cells to metabolize AEA, but are devoid of CB1R and hence are more sensitive to the pro-apoptotic activity of AEA. We did not further extend this study to 2-AG and the enzymes that degrade and synthesize it, because 2-AG does not have pro-apoptotic activity toward C6 cells or CHP100 cells, in keeping with the observation that it does not activate TRPV1 receptors. Furthermore, we have chosen human DAUDI leukemia cells, because they have active AMT and FAAH, and express functional CB2R. On the other hand, in DAUDI cells lipid rafts regulate important functions like exosome secretion, or growth arrest induced by antitumor drugs. In addition, we checked for the first time the effect of membrane cholesterol depletion or enrichment on 2-AG metabolism in C6 cells and DAUDI cells. In conclusion, this study monitor the effect of lipid rafts integrity on all the major proteins that bind and metabolize AEA and 2-AG, both in neuronal and immune cells. The results point out that CB1R and endocannabinoid transporters are probably localized within lipid rafts, at variace with CB2R and the other proteins of the endocannabinoid system.
Sampey, Brante P. "Studies of the adduction of hepatocellular proteins by 4-HNE in animals [sic] models of alcoholic liver disease : systematic analysis of hepatocellular Erk 1/2 modulation and dysregulation of the Erk-Elk-AP1 signal transduction pathway /." Connect to full text via ProQuest. IP filtered, 2005.
Typescript. Includes bibliographical references (leaves 141-156). Free to UCDHSC affiliates. Online version available via ProQuest Digital Dissertations;
Metcalfe, Maureen Grage. "Two-dimensional crystallization of archaeal signal peptide peptidases for structural studies by electron crystrallography." Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53984.
Lautscham, Lena Astrid [Verfasser], and Ben [Akademischer Betreuer] Fabry. "Cell migration and mechanosensitive signal transduction on 2-dimensional biomembrane-mimicking lipid bilayer stacks and in confined 3-dimensional microstructures / Lena Astrid Lautscham. Gutachter: Ben Fabry." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2015. http://d-nb.info/1076166105/34.
Casiraghi, Marina. "Functional modulation of a G protein-coupled receptor conformational landscape in a lipid bilayer." Thesis, Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCC138/document.
G protein-coupled receptors (GPCRs) are the largest family of integral membrane protein receptors present in most eukaryotic cells. They play a key role in signal transduction and understanding their signalling mechanism represents one of the main issues in biology today. In the characterization of the energy landscape of these receptors, at the atomic scale, X-ray crystal atomic structures published during the last decade represent the major breakthrough and contribution in the structural biology of GPCRs. They represent a precious starting point in the understanding of the mechanism of signal transduction by placing structures in the conformational ensemble of these receptors along the activation pathway. To complete these static snapshots that correspond to low energy and highly populated states, a characterization of the whole conformational ensemble and associated kinetic barriers is fundamental to complete the picture. To this aim we proposed an innovative approach to observe GPCRs dynamic conformational landscape and how it is modulated by ligands and lipids, that are known to play a key role in membrane protein structures and functions (e.g.). One of the most appropriate tool to explore GPCR kinetic barriers is solution state NMR. To do so, we used 13CH3 probes immersed in a perdeuterated environment, the most appropriate isotope-labelling scheme to investigate conformational landscapes of large proteins or protein complexes with this spectroscopy. We chose Escherichia coli as expression system for its ability to grow in very hostile conditions like 100%-D2O solutions. In order to overcome the usual expression issues concerning GPCRs, we applied an innovative protocol which targets the expression directly to inclusion bodies. This allows the production of high amounts of proteins (up to 6 mg/litre of culture of pure 13CH3-u-2H-GPCRs). Once purified, receptors are folded in amphipols and then transferred to nanometric lipid bilayers or nanodiscs. Importantly quantitative pharmacological measurements indicate that receptors embedded in NLBs following this protocol are stable and fully active in the conditions of the NMR experiments. NMR investigation of a GPCR in a NLB gave rise to a resolution never achieved in the field thanks to a fine tuned biochemistry and a perdeuteration of the receptor. According to our data, the prototypical receptor, the leukotriene B4 receptor (BLT2), is able to explore multiple different conformations, even in the unliganded state, including the active state. This conformational landscape is further modulated by ligands and lipids. In particular, we observed that an increment in the sterol content of the membrane modifies the distribution of the different conformational states of the receptor in favour of the active one, indicating a positive allosteric regulation of the sterol on the activation of this receptor, as confirmed by GTP-to-G protein binding measurements. This property of the sterol is likely important for the control of the signalling properties of GPCRs
Panakova, Daniela. "Lipoprotein particles associate with lipid-linked proteins and are required for long-range Wingless and Hedgehog signaling." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2005. http://nbn-resolving.de/urn:nbn:de:swb:14-1122025765300-27455.
Poidevin, Mickaël. "La synthèse d'acides gras dans des cellules spécialisées agit à distance sur le processus d'activation des ovocytes chez la drosophile." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASL016.
A statistical study by the World Health Organization revealed that one adult over six is affected by infertility problems. This major social issue is complex and multifactorial, with worldwide trends that are difficult to assess. It is therefore essential to carry out more research to better understand not only the evolution of infertility, but also the cellular and molecular mechanisms leading to efficient fertility.Serendipitously, we discovered that a genetic screen to enzymes responsible for fatty acid synthesis in specialized Drosophila cells provoked a sterile phenotype. These specialized cells, called as oenocytes, are essential for fatty acid metabolism, and are involved in numerous processes, including lipid homeostasis, protection against desiccation and pheromonal communication.My work shows that the synthesis of one or more very long-chain fatty acids in oenocytes is essential for female fertility, and that a defect in this synthesis causes spermatozoa to be retaintion in the storage organs, spermathecae and seminal receptacle. I have shown that the sterility phenotype is not linked to a defect in sperm activity, and that sperm fertilize mature oocytes efficiently. On the other hand, my results indicate that the eggs show an activation defect preventing their development.In insects, activation of the mature oocyte, which leads to embryonic development, is not dependent on sperm entry as in mammals. This activation is triggered by a calcium signal while the oocyte moves through the female genital tract. Taken together, my results show for the first time that an extra-genital lipid-signal triggers the activation of mature oocytes, thus enabling the induction of embryonic development
Waterstradt, Katja. "Der Einfluss des Cholesterolgehaltes der Diskmembranen des Stäbchenaußensegmentes auf die ersten Schritte der visuellen Signaltransduktion." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2009. http://dx.doi.org/10.18452/15949.
The rod outer segment consists of a stack of flat membrane saccules called disc membranes. Along this stack a cholesterol gradient exists with 24 mol% cholesterol in the basal and only 5 mol% in the apical disc membranes. The outer segment contains all the proteins necessary for signal transduction. The photoreceptor rhodopsin as integral membrane protein is embedded in the disc membrane. The G protein transducin and the effector protein phosphodiesterase (PDE) are soluble proteins with lipid modifications, which are associated reversibly to the membrane surface. Disc membranes with different cholesterol contents were prepared to simulate the cholesterol gradient along the rod outer segment and to investigate the influence of disc membrane cholesterol content of these three proteins. Investigations of the transversal distribution of cholesterol in the disc membrane revealed a fast transmembrane movement with a half life of less than one minute at 35 °C. Further, head group specific interactions between cholesterol and phosphatidylcholine could be shown. The Meta I Meta II equilibrium after light activation of rhodopsin was shifted to the Meta I (inactive) site in membranes with high cholesterol. In this work it was shown that in the presence of transducin this equilibrium is shifted completely to the Meta II (active) site because transducin stabilizes specifically the Meta II form of the receptor. Hence the reduced Meta II formation in disc membranes with high cholesterol could be compensated by transducin. The speed of transducin activation is decelerated. By the increased cholesterol content membrane properties are optimized to the binding of transducin and PDE via their lipid modifications. Thus the signal transduction can take place also in disc membranes with high cholesterol.
Ravacci, Graziela Rosa. "Desestruturação de lipid rafts por ácido docosaexaenoico (DHA) induz apoptose em células epiteliais luminais da glândula mamária humana transformadas pela superexpressão de HER-2." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/5/5155/tde-19042013-114655/.
HER-2 receptor overexpression is a cellular abnormality of great clinical significance in breast cancer. It is described in approximately 30% of breast carcinomas, including preneoplasic and malignant lesions, and is associated with poor prognosis. Hyperactivation of HER-2 receptors, a natural consequence of its overexpression, promotes aberrant cell proliferation and tumorigenesis. For signal activation and transduction to occur, HER-2 must be localized in specific compartments in the cell membrane: the lipid rafts. Therefore, we hypothesize that a greater number of HER-2 receptors could indicate a greater quantity of lipid rafts. To test this, we used an oncogenic transformation model that specifically allowed assessment of the effects of HER-2 overexpression and identification of the quantity of lipid rafts: an HB4a cell line derived from normal human breast tissue luminal epithelial cells with low HER-2 expression, and an HB4aC5.2 cell line, a clone derived from HB4a that overexpresses HER-2 receptors. In the HB4aC5.2 cells, HER-2 overexpression was accompanied by an increase in lipid rafts in cell membranes as well as hyperactivation of survival signals, proliferation (increased activation of the proteins Akt and ERK1/2, respectively), and an increased rate of proliferation, compared to the normal HB4a line. In addition, HER-2 overexpression was associated with increased cellular lipogenesis (lipogenic phenotype), dependent on the increased activation of the FASN enzyme and the overexpression of DEPTOR. FASN is responsible for the synthesis of palmitate, used to synthesize lipid rafts. Overexpression of DEPTOR by modulating PPAR? transcriptional activity, may avoid lipotoxicity from excess palmitate. Moreover, DEPTOR, with its ability to reduce mTORC1 complex activity, contributes to cell survival dependent on Akt. To continue, we considered as a second hypothesis that the disruption of lipid rafts could negatively influence HER-2 receptor activation. For this, we treated the same cell lines described above with docosahexaenoic acid (DHA), a omega-3 fatty acid. Our results showed that in HB4aC5.2 cells DHA treatment disrupted the lipid rafts, inhibited signaling initiated by HER-2 receptors (reduced activation of Akt, ERK1/2, and FASN proteins, PPAR? transcriptional activity, and DEPTOR expression) and reversed the lipogenic phenotype. In addition, these cellular and molecular changes were accompanied by a significant induction of apoptosis and death. The same changes were not observed in normal HB4a cells. In conclusion, the present study reinforces the association between HER-2 presence and lipid rafts. It also indicates that the disruption of lipid rafts by DHA reduces HER-2 signaling. Finally, it suggests that DHA-induced disturbances in lipid rafts may represent a useful tool in controlling aberrant signaling triggered by HER-2 receptors, and indicate therapeutic potential in DHA supplementation for chemoprevention and treatment of HER-2 positive breast cancer.
Tellier, Edwige. "Le TNF alpha : maturation par ADAM-17 et activation d'une voie de signalisation sphingomyéline-céramide." Toulouse 3, 2008. http://thesesups.ups-tlse.fr/725/.
TNF alpha (Tumor Necrosis Factor alpha) is a pro-inflammatory cytokine existing in two molecular forms, a transmembrane form cleaved to produced a soluble form. TNF alpha is implicated in numerous physiological and physiopathologicals processes such as atherosclerosis. Within the lesions, soluble TNF alpha seems to play a major role : genetically modified mice expressing exclusively a transmembrane form of TNF alpha develop atherosclerosis lesions with an inflammatory state which is significantly reduced compared to lesions of wild type mice (Canault et al. , 2004). Cleavage of TNF alpha transmembrane form is due to the metalloproteinase ADAM-17 (A Disintegrine and Metalloproteinase-17). Today, regulation of ADAM-17 cleavage activity is poorly documented. We have voiced hypothesis that the membrane localization of ADAM-17 and its substrates was implicated to its regulation. We show that ADAM-17 mature form is localized into membrane particular domains, the lipid rafts (Tellier et al. , 2006) and that this localization determined its activity. We also show that cell cholesterol homeostasis modifications by HDLs lead to a ADAM-17 substrates cleavage perturbations (Tellier et al. , 2007). TNF alpha induce number signaling pathways in atherosclerosis plaques cells, leading to several effects including SMC (smooth muscle cells) proliferation. Literature show that TNF alpha active neutral sphingomyelinase (nSMase) and that nSMase mitogene effect involve MMP2 and MT1-MMP (Auge et al. , 2004 ; Nègre-Salvayre et al. , 2005). We have postulated that TNF alpha could induce cell proliferation by a pathway implicating metalloproteinases and neutral SMase activation. Our results show that TNF alpha induced mesenchymal cells proliferation is due to pro-protein convertase furin, MT1-MMP ad MMP2 metalloproteinases sequential activation followed by sphingomyeline/ceramide pathway (Tellier et al. , 2008). In conclusion, our results give new data on the TNF alpha biodisponibility regulation as on pro-atherogene effect via stress mitogene pathway activation
Edwards, Bethanie Rachele. "The biogeochemistry of lipid derived infochemical signals in the ocean." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/103254.
Cataloged from PDF version of thesis.
Includes bibliographical references.
The role of oxylipins in ocean biogeochemistry was investigated using microcosm amendment experiments, environmental lipidomics, and culture based studies. Oxylipins are a bioactive class of secondary metabolites produced by diatoms and other eukaryotic phytoplankton. Previous research has focused mainly on one class of oxylipins, polyunsaturated aldehydes (PUAs), and their impacts on copepods. And few studies have looked at the impacts of oxylipins in situ. Here I show that oxylipins have the potential to impact carbon flux attenuation, oxylipin production in situ is linked to diatom bloom decline and viruses, and oxylipins deter microzooplankton grazing. Sinking particles collected in the North Atlantic were determined to be hot spots for PUAs with concentrations in the micromolar range. Natural particle associated microbial communities exhibited a dose dependent response to PUAs. Stimulatory PUA concentrations ranged from 1-10 ptM, resulting in enhanced remineralization of organic matter by particle associated microbes. Thus, PUAs produced during bloom decline may lead to greater flux attenuation and nutrient recycling. A novel lipidomics approach was applied along a cruise track in the California Coastal System revealing that canonical diatom free fatty acids and oxylipins dominated the dissolved lipidome and oxylipin abundance was correlated with diatom bloom demise as assessed by phaeophytin and biogenic Si. RNA viruses were likely the cause of diatom bloom demise and may have induced oxylipin production. The link between viruses and oxylipins represents a new infochemical signaling pathway in the ocean. Many oxylipins that are novel to the marine environment were also identified. The dissolved lipidome was sampled during grazing experiments with the microzooplankton grazer Oxyrrhis marina and both wild type Phaeodactylum tricornutum and a chronically stressed, transgenic strain (PtNOA). Grazing was suppressed in the PtNOA treatments compared to the WT, likely due to upregulation of small unknown lipophilic molecules. This suggests that cellular stress and oxylipin production may deter microzooplankton grazing in the environment potentially altering the transfer of energy through the microbial food web. By employing interdisciplinary approaches, we have learned that oxylipins production in situ is linked to bloom decline and the bioactivity of these compounds has significant implications for ocean biogeochemical cycles.
by Bethanie Rachele Edwards.
Ph. D.
Dove, Stephen K. D. "Inositol lipids and signalling in higher plants." Thesis, University of East Anglia, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338295.
Balogh, Gabor. "Role of membranes in mammalian stress response : sensing, lipid signals and adaptation." Thesis, Cardiff University, 2011. http://orca.cf.ac.uk/26933/.
Rogalski, Sherri Lynn. "Modulation of Kir3 by lipids and tyrosine phosphorylation /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/6274.
Grimault, Stephan. "Détermination des propriétés du signal RMN par une approche numérique : application aux expériences de diffusion et d'imagerie fonctionnelle." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10157.
Rowe, Daniel C. "Analysis of Toll-Like Receptor 4 Signal Transduction and IRF3 Activation in the Innate Immune Response: A Dissertation." eScholarship@UMMS, 2006. https://escholarship.umassmed.edu/gsbs_diss/163.
Tolentino, Timothy P. "The Roles of Membrane Rafts in CD32A Mediated Formation of a Phagocytic Contact Area." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16127.
Hayes, Susan J. "Analysis of FYVE Domain-Containing Proteins in Signaling and Endocytosis: a dissertation." eScholarship@UMMS, 2003. http://escholarship.umassmed.edu/gsbs_diss/208.
Hayes, Susan J. "Analysis of FYVE Domain-Containing Proteins in Signaling and Endocytosis: a dissertation." eScholarship@UMMS, 2004. https://escholarship.umassmed.edu/gsbs_diss/208.
Mitra, Ganguli Tora. "Modulation of Voltage-Gated N-Type Calcium Channels by G Protein-Coupled Receptors Involves Lipids and Proteins: A Dissertation." eScholarship@UMMS, 2008. https://escholarship.umassmed.edu/gsbs_diss/389.
Cazade, Magali. "Nouvelles voies de modulation des canaux calciques de type T." Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20106.
New pathways of regulation of T-type calcium channels.Thanks to their role in cellular excitability and calcium homeostasis, T-type calcium channels are involved in several physiological functions such as sleep or control of cardiac rythmicity and vascular tone. They are also involved in some diseases such as pain or epilepsy. The regulation of T-type calcium channels is still poorly understood and that is the challenge of this thesis.In a first part of the study, we caracterised the effect of some endogenous lipids on these channels, particularly the metabolites of arachidonic acid, and identified the 5,6-EET as a new blocker of T-type channels. We then evaluated the existence of a binding site of lipoamino acids on T-type channels using binding experiments made with a specific inhibitor of these channels, the TTA-A1 molecule.In a second part, we studied the regulation of T-type channels by calcium. We showed that a calcium entry through T-type channels or through P2X4 and NMDA receptors activation induced an inhibition of T-type current. Calcium would activate a phosphatase which would trigger a shift of the steady-state inactivation curve toward negative potentials, reducing the availability of channels. This phenomenon of current inhibition due to calcium entry may be a feedback mechanism limiting calcium entry in the cell to avoid toxicity due to a too high intracellular calcium concentration. After this inhibition, when calcium entry is stopped, the current increases. This increase seems to be due to the intervention of the Pak protein kinase which would make T-type channels available again.In conclusion, we studied and caracterised tow new mechanisms of T-type channels regulation: a modulation by lipids, and a modulation by calcium and the Pak protein kinase
Rodríguez, Solovey Leisa Natacha. "IDENTIFICATION OF TARGETS AND AUXILIARY PROTEINS OF PYR/PYL/RCAR ABA RECEPTORS: PROTEIN PHOSPHATASES TYPE 2C (PP2Cs) AND C2-DOMAIN ABA-RELATED PROTEINS (CARs)." Doctoral thesis, Universitat Politècnica de València, 2015. http://hdl.handle.net/10251/58862.
[ES] RESUMEN La señalización por la hormona vegetal ácido abscísico (ABA) desempeña un papel crítico en la regulación del crecimiento de la raíz y en la arquitectura del sistema radical. La promoción de crecimiento de la raíz en condiciones de estrés hídrico mediada por ABA es clave para la supervivencia de las plantas bajo condiciones limitantes de agua. En este trabajo, hemos explorado el papel de los receptores PYR/PYL/RCAR (PYRABACTIN RESISTANCE1 (PYR1)/PYR1 LIKE (PYL)/ REGULATORY COMPONENTS OF ABA RECEPTORS) de Arabidopsis (Arabidopsis thaliana) en la ruta de señalización de ABA en raíz. Así, hemos descubierto que el receptor de ABA PYL8 juega un papel no redundante en la regulación de la percepción de ABA en raíz. Inesperadamente, dada la naturaleza multigénica y la redundancia funcional parcial observada en la familia PYR/PYL/RCAR, el mutante pyl8 fue el único mutante sencillo de pérdida de función de los receptores PYR/PYL/RCAR que mostraba una sensibilidad reducida a la inhibición del crecimiento mediada por ABA en raíz. Este efecto se debe a la falta de inhibición mediada por PYL8 de varias fosfatasas del grupo A tipo 2C (PP2Cs), ya que PYL8 es capaz de interactuar in vivo con al menos cinco PP2Cs, denominadas HYPERSENSITIVE TO ABA1 (HAB1), HAB2, ABAINSENSITIVE1 (ABI1), ABI2, and PP2CA/ABA-HYPERSENSITIVE GERMINATION3 según lo han revelado la purificación por afinidad en tándem (TAP por sus siglas en inglés) y estudios proteómicos de espectrometría de masas. La transducción de la señal del ABA localizada en la membrana plasmática celular juega un papel crucial en los pasos iniciales de la señalización de la fitohormona, pero los mecanismos moleculares que unen los componentes básicos de la señalización y la membrana plasmática no están claros. Estudiando las interacciones de los receptores del ABA PYR/PYL/RCAR con la membrana plasmática hemos encontrado que éstos pueden interaccionar transitoriamente con ella de forma dependiente de calcio gracias a una familia de proteínas con dominios C2 relacionadas con la ruta de señalización de ABA (denominadas C2-domain ABA-related (CAR) proteins). Específicamente, se encontró que PYL4 interacciona de manera independiente de ABA con CAR1 tanto en la membrana plasmática como en el núcleo de las células vegetales. La proteína CAR1 pertenece a una familia multigénica constituida por 10 miembros en Arabidopsis thaliana, desde CAR1 hasta CAR10, y que solo se encuentra en plantas. Los ensayos de complementación bi-molecular de fluorescencia y de co-immunoprecipitación confirmaron la interacción en células vegetales tanto de PYL4-CAR1 como de otras parejas de PYR/PYL-CAR. La cristalización de la proteína CAR4 reveló que, además de un dominio C2 clásico de unión a lípidos dependiente de calcio, las proteínas de la familia CAR presentan un dominio específico que probablemente es responsable de la interacción con los receptores PYR/PYL/RCAR y de su posterior reclutamiento a las vesículas de fosfolípidos. Esta interacción es relevante para la función de los receptores PYR/PYL/RCAR en la señalización del ABA, ya que diferentes mutantes triples car de pérdida de función, que tienen afectados los genes CAR1, CAR4, CAR5, y CAR9, demostraron una reducción de la sensibilidad al ABA en ensayos de establecimiento de plántula y crecimiento de la raíz. En resumen, hemos identificado nueva familia de proteínas que son capaces mediar las interacciones transitorias dependientes de Ca2+ con vesículas de fosfolípidos, lo que a su vez afecta localización de PYR/PYL/RCAR y regula positivamente la señalización de ABA.
[CAT] RESUM La senyalització per l'hormona vegetal àcid abcíssic (ABA) exerceix un paper crític en la regulació del creixement de l'arrel i també en l'arquitectura del sistema radical. La promoció del creixement de l'arrel en condicions d'estrés hídric, regulada per ABA és clau per la supervivència de les plantes sota condicions limitants d'aigua. Amb aquest treball, hem investigat el paper dels receptors PYR/PYL/RCAR (PYRABACTIN RESISTANCE1 (PYR1)/PYR1 LIKE (PYL)/ REGULATORY COMPONENTS OF ABA RECEPTORS) d'Arabidopsis (Arabidopsis thaliana) en el camí de senyalització d'ABA en arrel. Així, hem descobert que el receptor d'ABA PYL8 exerceix un paper no redundant en la regulació de la percepció d'ABA en arrel. Inesperadament, donada la naturalesa multigènica i la redundància funcional parcial que s'observa en la família PYR/PYL/RCAR, el mutant pyl8 va ser l'únic mutant senzill de pèrdua de funció dels receptors PYR/PYL/RCAR que mostrava una sensibilitat reduïda a la inhibició del creixement mitjançada per l'ABA en l'arrel. Doncs aquest efecte es deu a la falta d'inhibició regulada per PYL8 de diverses fosfatases del grup A tipus 2C (PP2Cs), ja que PYL8 té la capacitat d'interactuar in vivo almenys amb cinc PP2Cs, anomenades HYPERSENSITIVE TO ABA1 (HAB1), HAB2, ABAINSENSITIVE1 (ABI1), ABI2, and PP2CA/ABAHYPERSENSITIVE GERMINATION3 segons ho han revelat per una banda la purificació per afinitat en tàndem (TAP són les seues sigles en anglés) i per altra banda, estudis proteòmics d'espectrometria de masses. Pel que fa a la transducció del senyal del l'ABA, la qual es localitza en la membrana plasmàtica cel¿lular, juga un paper molt important en els primers instants de la senyalització de la fitohormona, no obstant això els mecanismes moleculars que uneixen els components bàsics d'aquesta senyalització amb la membrana plasmàtica, no es troben del tot clars. Per tant, s'han estudiat les interaccions que tenen els receptors del ABA PYR/PYL/RCAR amb la membrana plasmàtica, i hem trobat que aquests tenen la capacitat d'interaccionar transitòriament amb la membrana de forma dependent al calci, gràcies a una família de proteïnes amb domini C2, les quals es troben relacionades amb la ruta de senyalització d'ABA(anomenades C2domain ABArelated (CAR) proteins).Específicament, es va trobar que PYL4 interacciona d'una manera independent al ABA amb CAR1, tant en la membrana plasmàtica, com en el nucli de les cèl¿lules vegetals. La proteïna CAR1 pertany a la família multigènica constituïda per 10 components en Arabidopsis thaliana, des de CAR1 fins CAR10, que tan sols es troba en plantes. Els assajos de complementació bimolecular de fluorescència i de co-immunoprecipitació, van confirmar la interacció en cèl¿lules vegetals, tant de PYL4CAR1 com d'altres parelles de PYR/PYL-CAR. La cristal¿lització de la proteïna CAR4 va revelar que, a més d'un domini C2 clàssic de unió a lípids dependent del calci, les proteïnes de la família CAR presenten un domini PYR/PYL/RCAR, i del seu posterior reclutament a les vesícules fosfolipídiques. Doncs, aquesta interacció és rellevant en la funció dels receptors PYR/PYL/RCAR, ja que participa en la senyalització del l'ABA. Aquesta interacció es clau per a la funció dels receptors, ja que diferents mutants triples car de pèrdua de funció, els quals posseïxen afectats els gens CAR1, CAR4, CAR5 i CAR9, van mostrar una reducció de la sensibilitat a l'ABA en assajos d'establiment de plàntula i creixement de l'arrel. En conclusió, hem identificat una nova família de proteïnes amb la capacitat d'organitzar les interaccions transitòries dependents del calci amb vesícules de fosfolípids, fet que al seu torn afecta la localització de PYR/PYL/RCAR i regula positivament la senyalització d'ABA.
Rodríguez Solovey, LN. (2015). IDENTIFICATION OF TARGETS AND AUXILIARY PROTEINS OF PYR/PYL/RCAR ABA RECEPTORS: PROTEIN PHOSPHATASES TYPE 2C (PP2Cs) AND C2-DOMAIN ABA-RELATED PROTEINS (CARs) [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/58862
TESIS
Abdoul-Azize, Souleymane. "Implication de la signalisation calcique et des MAP kinases dans la perception gustative lipidique." Phd thesis, Université de Bourgogne, 2013. http://tel.archives-ouvertes.fr/tel-01018378.
Chen, Bo-Cheng, and 陳柏誠. "Validation of lipid contamination elimination using signal space projection on phantom." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/499hwf.
國立臺灣科技大學
電子工程系
107
Lipid contamination from the intense subcutaneous lipid signal that produces Gibbs ringing artifacts may complicate the quantitation of metabolites in the Magnetic Resonance Spectroscopic Image. In 2D MRSI, lipid suppression is usually achieved by placing 8 outer volume saturation bands (OVS) around the brain with subcutaneous lipids or use inversion recovery to eliminate fat signals. In this study, post-processing method based on spatial signal projection (SSP) was used to achieve the effect of suppressing lipid signal. SSP extracts signal components of lipids and removes them to achieve effective lipid suppression. In this experiment, the effect of lipid suppressions was tested in brain phantoms. Data of brain phantom were collected by echo planar spectroscopic imaging (EPSI), and the concentration of metabolites after SSP lipid suppression was compared with the known concentration of brain phantom. The feasibility of SSP method for lipid suppression was demonstrated.
Hooks, Shelley Brown. "Regulation of Lysophosphatidic Acid signaling by Lipid Phosphate Phosphatases /." 2001. http://wwwlib.umi.com/dissertations/fullcit/3000142.
Lu, Li-Ming, and 呂理銘. "Differential signal pathways induced by LPS and Lipid A in human T cells." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/42304161836953702545.
國立陽明大學
生理學研究所
91
Previous works indicated that Bacterial lipoplysaccharide (LPS) and it's toxically center, lipid A (LA), stimulated NF-κB mRNA expression and NF-κB protein activation, but not the proliferation in T cells. The increasing in intracellular calcium was through phosphoinositide 3-kinase (PI3K) pathway by Lipid A, whereas, the increases in intracellular pH (pHi) was through protein kinase C (PKC)/phospholipase D (PLD) pathway in T cells. Therefore, the aim of this study was to investigate whether gene expression by LPS or LA were regulated by differential signals stimulated in human peripheral T cells. The changes in intracellular calcium ([Ca2+]i) were measured by fluorescent dye, Fura-2, and the mRNA expression in Toll-like receptors (TLRs, TLR2 and TLR4), NF-κB and PLD were measured by reverse transcriptional-polymerase chain reaction (RT-PCR). The T cell proliferation was determined by [3H]-thymidine incorporation. The appearance of cell marker CD40L、TLR2、TLR4 on T cells were analyzed by flow cytometry. Inhibitors of PI3K, LY294002 and Wortmanin, inhibitor of PKCθ, Rottlerin, and inhibitor of protein tyrosine kinase (PTK), Genistein were used to explore the alternation on signals and the expression by lipid A. The results indicate that 1) The Ca2+ influx, but not intracellular calcium release by LA and was suppressed by Wortmanin and LY294002; 2) The mRNA expression on PLD、TLR4 was induced by LPS at 30 min and reached a peak at 1h. In addition, the mRNA expression on NF-κB and TLR2 was induced by LPS and reached a peak at 1 h. In contrast, LA did not stimulate PLD and TLR2 expression but increased the expression of NF-κB at 1h and reached a peak at 4 h; 3) The mRNA expression on NF-κB by LA was suppressed by pretreate cells with EGTA and Wortmanin, however, the expression on TLR4 was not affected; 4) Both LPS and LA did not affect the expression of cell surface protein marker CD40L. LPS increased the expression of cell surface protein markers, TLR2 and TLR4. Whereas, LA increased the expression of TLR2 but not TLR4; 5) Combinations of LA and PMA did not alter [3H]-thymidine incorporation into T cells. In summary, LPS could induce the mRNA expression on PLD, NF-κB, TLR2 and TLR4 as well as the cell surface protein on TLR2 and TLR4. In contrast, LA only increased mRNA expression of NF-κB and TLR4 as well as the cell surface protein on TLR2. In conclusion, the mRNA expression on PLD and TLR2 was the only differential signal that found by LPS and LA, thus, LPS had better enhancement than LA on T cell natural immunity.
Pott, Markus Philipp [Verfasser]. "Organic hydroperoxide-induced lipid peroxidation (LPO) and signal transduction pathways in human keratinocytes / vorgelegt von Markus Philipp Pott." 2002. http://d-nb.info/96545293X/34.
Walli, Rehab [Verfasser]. "The role of lipid rafts in UVA radiation-induced signal transduction in human keratinocytes / vorgelegt von Rehab Walli." 2009. http://d-nb.info/100104326X/34.
Nelson, Christopher David. "Characterization of Beta-arrestin-Modulated Lipid Kinase Activities for Diacylglycerol and Phosphatidylinositol 4-Phosphate." Diss., 2007. http://hdl.handle.net/10161/206.
Turk, Harmony 1985. "The Role of Docosahexaenoic Acid in Regulation of Epidermal Growth Factor Receptor Activation and Function." Thesis, 2012. http://hdl.handle.net/1969.1/148103.
Li, Pin. "Effects of carbon nanotubes on airway epithelial cells and model lipid bilayers : proteomic and biophysical studies." Thesis, 2014. http://hdl.handle.net/1805/5968.
Carbon nanomaterials are widely produced and used in industry, medicine and scientific research. To examine the impact of exposure to nanoparticles on human health, the human airway epithelial cell line, Calu-3, was used to evaluate changes in the cellular proteome that could account for alterations in cellular function of airway epithelia after 24 h exposure to 10 μg/mL and 100 ng/mL of two common carbon nanoparticles, singleand multi-wall carbon nanotubes (SWCNT, MWCNT). After exposure to the nanoparticles, label-free quantitative mass spectrometry (LFQMS) was used to study differential protein expression. Ingenuity Pathway Analysis (IPA) was used to conduct a bioinformatics analysis of proteins identified by LFQMS. Interestingly, after exposure to a high concentration (10 μg/mL; 0.4 μg/cm2) of MWCNT or SWCNT, only 8 and 13 proteins, respectively, exhibited changes in abundance. In contrast, the abundance of hundreds of proteins was altered in response to a low concentration (100 ng/mL; 4 ng/cm2) of either CNT. Of the 281 and 282 proteins that were significantly altered in response to MWCNT or SWCNT, respectively, 231 proteins were the same. Bioinformatic analyses found that the proteins common to both kinds of nanotubes are associated with the cellular functions of cell death and survival, cell-to-cell signaling and interaction, cellular assembly and organization, cellular growth and proliferation, infectious disease, molecular transport and protein synthesis. The decrease in expression of the majority proteins suggests a general stress response to protect cells. The STRING database was used to analyze the various functional protein networks. Interestingly, some proteins like cadherin 1 (CDH1), signal transducer and activator of transcription 1 (STAT1), junction plakoglobin (JUP), and apoptosis-associated speck-like protein containing a CARD (PYCARD), appear in several functional categories and tend to be in the center of the networks. This central positioning suggests they may play important roles in multiple cellular functions and activities that are altered in response to carbon nanotube exposure. To examine the effect of nanotubes on the plasma membrane, we investigated the interaction of short purified MWCNT with model lipid membranes using a planar bilayer workstation. Bilayer lipid membranes were synthesized using neutral 1, 2-diphytanoylsn-glycero-3-phosphocholine (DPhPC) in 1 M KCl. The ion channel model protein, Gramicidin A (gA), was incorporated into the bilayers and used to measure the effect of MWCNT on ion transport. The opening and closing of ion channels, amplitude of current, and open probability and lifetime of ion channels were measured and analyzed by Clampfit. The presence of an intermediate concentration of MWCNT (2 μg/ml) could be related to a statistically significant decrease of the open probability and lifetime of gA channels. The proteomic studies revealed changes in response to CNT exposure. An analysis of the changes using multiple databases revealed alterations in pathways, which were consistent with the physiological changes that were observed in cultured cells exposed to very low concentrations of CNT. The physiological changes included the break down of the barrier function and the inhibition of the mucocillary clearance, both of which could increase the risk of CNT’s toxicity to human health. The biophysical studies indicate MWCNTs have an effect on single channel kinetics of Gramicidin A model cation channel. These changes are consistent with the inhibitory effect of nanoparticles on hormone stimulated transepithelial ion flux, but additional experiments will be necessary to substantiate this correlation.
Mar, Fernando José Milhazes. "Novel targets to improve axonal regeneration in the CNS: the role of myelin lipid inhibitors, injury signals and axonal transport." Doctoral thesis, 2014. https://repositorio-aberto.up.pt/handle/10216/75782.
Mar, Fernando José Milhazes. "Novel targets to improve axonal regeneration in the CNS: the role of myelin lipid inhibitors, injury signals and axonal transport." Tese, 2014. https://repositorio-aberto.up.pt/handle/10216/75782.
(6901280), Brianna N. Hudson. "Insights into the Role of the Membrane on Phospholipase C Beta and G Alpha Q-Mediated Activation." Thesis, 2019.