Dissertations / Theses on the topic 'Protein 1'
To see the other types of publications on this topic, follow the link: Protein 1.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Protein 1.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Stylianou, Julianna. "Protein-protein interaction of HSV-1 tegument proteins." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/24663.
Full textAbstract:
Herpes simplex virus type 1 virions contain a proteinaceous layer between the nucleocapsid and the virus envelope termed the tegument. The mechanism underlying tegumentation remains largely undefined for all herpesviruses, as does the role of many tegument proteins in virus replication. The networks of protein interactions involved in virus assembly have been largely explored and although large-scale studies have been carried out using yeast two hybrid analyses of herpesvirus protein interactions, few of the identified networks have been validated in infected cells. Here, the molecular interactions that occur between the major tegument proteins VP22, VP16 and VP13/14 and a range of glycoproteins and tegument proteins were defined in detail. Two alternative studies were performed from infected cells, however one based on the purification of GFP-tagged proteins and their protein partners proved more successful. These studies validated previous findings and also identified VP13/14, UL21, UL16 and vhs as novel binding partners of VP22, and VP22, UL21, UL16 and vhs as novel binding partners of VP13/14. Thus, these results have led to the identification of two discrete tegument protein complexes in the infected cell: VP22-VP16-VP13/14-vhs and VP22-VP13/14-UL21-UL16. To investigate the nature of the VP22-VP16-VP13/14-vhs complex in more detail, a number of techniques were used and showed that VP22 and VP13/14 both bind directly to the C-terminus of VP16, but were unable to interact with each other. As anticipated from other studies on transfected cell extracts, vhs was shown to be incorporated into this complex by virtue of its direct binding to VP16 during infection, and did not have the capacity to interact directly with VP22. This work has established a defined network of protein-protein interactions encompassing over one third of tegument proteins, and will improve our understanding of the wider protein interaction networks that lead to the assembly of the herpesvirus tegument.
2
Tse, Muk-hei. "Investigations on recombinant Arabidopsis acyl-coenzyme A binding protein 1." View the Table of Contents & Abstract, 2005. http://sunzi.lib.hku.hk/hkuto/record/B36427664.
Full text
3
Lam, Wai Kwan. "Investigation of interaction between solube adenylyl cyclase and p34SEI-1 /." View abstract or full-text, 2010. http://library.ust.hk/cgi/db/thesis.pl?BIOL%202010%20LAM.
Full text
4
Tse, Muk-hei, and 謝牧熙. "Investigations on recombinant Arabidopsis acyl-coenzyme A binding protein 1." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B36427664.
Full text
5
Bennett, D. H. "Protein phosphatase type 1 binding proteins in Drosophila melanogaster." Thesis, University of Oxford, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365689.
Full text
6
Hetti, Arachchilage Madara Dilhani. "Coevolution of epitopes in HIV-1 pre-integration complex proteins: protein-protein interaction insights." Kent State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=kent1530646538935895.
Full text
7
Niessen, Sherry. "p120e4f-1 : a novel Bmi-1 interacting protein." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80343.
Full textAbstract:
We demonstrated that the Polycomb Group (Pc-G ) gene Bmi-1 is essential for the self-renewal of both normal and leukemic stem cells. The molecular pathways through which Bmi-1 regulates stem cell function remain undefined. We identified p120E4F-1 as a novel factor, which specifically interacts with Bmi-1 in the cytoplasmic fraction of hemopoietic cells. We observed that the ability of Bmi-1 to extend the proliferative/replicative lifespan of primary fibroblasts correlated with a down-regulation of p120E4F-1 protein levels. This function of Bmi-1 occurred without affecting p120E4F-1 mRNA levels suggestive of a direct interaction between the two proteins. Conversely, p120E4F-1 levels were found to be elevated in Bmi-1-/- progenitors of several types of cerebellar interneurons, providing a molecular basis for the neuronal proliferative defect observed in the Bmi-1 -/- cerebellum. From these studies, we propose that the ability of Bmi-1 to regulate stem/progenitor cell proliferation is in part mediated through the down-regulation of cytoplasmic p120 E4F-1 levels.
8
Lawrence, Charlotte. "Towards a small molecule inhibitor of the HIF-1/HIF-1 protein-protein interaction." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/374783/.
Full textAbstract:
Hypoxia-inducible factor (HIF) is a heterodimeric, oxygen-dependent, transcription factor that regulates the cellular response to hypoxia by directing the expression of multiple genes, such as those involved in angiogenesis and glucose transport. HIF activation has been shown to aid the survival of cancer cells in hypoxic regions; hence it is viewed as a potentially important target for cancer therapy. There are two predominant isoforms of HIF, HIF-1 and HIF-2, formed by heterodimerisation of HIF-1 or HIF-2, respectively, with HIF-1. The dimerisation of the two subunits is necessary for DNA-binding and subsequent activation of transcription. Miranda et al. (2013) have recently identified a six amino acid cyclic peptide inhibitor of HIF dimerisation (cyclo-CLLFVY); the Tat-tagged variant is called P1. This has shown activity within several cell-based assays.1 This project sought to identify which amino acid residues of cyclo-CLLFVY were critical to its activity by synthesising five alanine analogues and testing them in cell and biophysical assays. It was not possible to identify an active motif and it could be concluded that the specific conformation of the intact cyclic peptide is required for activity. The functionality of independently bacterially expressed fragments of HIF-1 and HIF-1 was also validated by an EMSA. The Tavassoli group used these proteins to establish the binding location of the inhibitor to the HIF-1-PAS-B domain (work by A. Tavassoli and A. Male).
9
Lubeseder-Martellato, Clara. "The guanylate binding protein-1." Diss., lmu, 2003. http://nbn-resolving.de/urn:nbn:de:bvb:19-11959.
Full text
10
Sarkar, Mohosin M. "Engineering Proteins with GFP: Study of Protein-Protein Interactions In vivo, Protein Expression and Solubility." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1261418776.
Full text
11
Lai, Chun Wan Jeffrey. "Mechanism of G Protein Beta-Gamma Assembly Mediated by Phosducin-Like Protein 1." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/3190.
Full textAbstract:
G-protein coupled receptor signaling (GPCR) is essential for regulating a large variety of hormonal, sensory and neuronal processes in eukaryotic cells. Because the regulation of these physiological responses is critical, GPCR signaling pathways are carefully controlled at different levels within the cascade. Phosducin-like protein 1 (PhLP1) can bind the G protein βγ dimer and participate in GPCR signaling. Recent evidence has supported the concept that PhLP1 can serve as a co-chaperone of the eukaryotic cytosolic chaperonin complex CCT/TRiC to mediate G βγ assembly. Although a general mechanism of PhLP1-mediated G βγ assembly has been postulated, many of the details about this process are still missing. Structural analysis of key complexes that are important intermediates in the G βγ assembly process can generate snapshots that provide molecular details of the mechanism beyond current understanding. We have isolated two important intermediates in the assembly process, the Gβ1-CCT and PhLP1-Gβ1-CCT complexes assembled in vivo in insect cells, and have determined their structures by cryo-electron microscopy (cryo-EM). Structural analysis reveals that Gβ1, representing the WD40 repeat proteins which are a major class of CCT substrates, interacts specifically with the apical domain of CCTβ. Gβ1 binding experiments with several chimeric CCT subunits confirm a strong interaction of Gβ1 with CCTβ and map Gβ1 binding to α-Helix 9 and the loop between β-strands 6 and 7. These regions are part of a hydrophobic surface of the CCTβ apical domain facing the chaperonin cavity. Docking the Gβ molecule into the two 3D reconstructions (Gβ1-CCT and PhLP1-Gβ1-CCT) reveals that upon PhLP1 binding to Gβ1-CCT, the quasi-folded Gβ molecule is constricted to a more native state and shifted to an angle that can lead to the release of folded Gβ1 from CCT. Moreover, mutagenesis of the CCTβ subunit suggests that PhLP1 can interact with the tip of the apical domain of CCTβ subunit at residue S260, which is a downstream phosphorylation target site of RSK and S6K kinases from the Ras-MAPK and mTOR pathways. These results reveal a novel mechanism of PhLP1-mediated Gβ folding and its release from CCT. The next important step in testing the PhLP1-mediated Gβγ assembly hypothesis is to investigate the function of PhLP1 in vivo. We have prepared a rod-specific PhLP1 conditional knockout mouse in which the physiological consequences of the loss of PhLP1 functions have been characterized. The loss of PhLP1 has led to profound consequences on the ability of these rods to detect light as a result of a significant reduction in the expression of transducin (Gt) subunits. Expression of other G protein subunits as well as Gβ5-RGS9-1 complexes was also greatly decreased, yet all of this occurs without resulting in rapid degeneration of the photoreceptor cells. These results show for the first time the essential nature of PhLP1 for Gβγ and Gβ5-RGS dimer assembly in vivo, confirming results from cell culture and structural studies.
12
Li, Chun-bong. "Mechanisms of HIV-1 Tat induced immune response." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B31537169.
Full text
13
Li, Chun-bong, and 李振邦. "Mechanisms of HIV-1 Tat induced immune response." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B31537169.
Full text
14
Smith, Stephanie Kathryn Fiona. "Structure/function of presenilin 1 in relation to Alzheimer's disease." Thesis, University of Bristol, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267017.
Full text
15
Striebinger, Hannah. "Membran-assoziierte Protein-Protein-Interaktionen des Herpes simplex-Virus 1." Diss., lmu, 2012. http://nbn-resolving.de/urn:nbn:de:bvb:19-146882.
Full text
16
Douglas, Chanel Catherine. "A study into the protein/protein interactions involved in HIV-1 capsid assembly." Thesis, Birmingham, Ala. : University of Alabama at Birmingham, 2007. https://www.mhsl.uab.edu/dt/2008r/douglas.pdf.
Full text
17
Hellborg, Fredrik. "Identification, cloning and characterization of the p53 induced gene human wig-1 /." Stockholm, 2004. http://diss.kib.ki.se/2004/91-7140-190-3/.
Full text
18
Gibson, Rosemary M. "Protein engineering of #Beta#-lactamase 1." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.256768.
Full text
19
Paxton, Camille Whitney. "Kelch related protein 1 in myogenesis." Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.611690.
Full text
20
Koscky, Paier Carlos Roberto 1983. "Caracterização estrutural do complexo protéico Calsarcina 1 : Calcineurina A." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/314411.
Full textAbstract:
Orientador: Kleber Gomes FranchiniTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-26T03:49:49Z (GMT). No. of bitstreams: 1 KosckyPaier_CarlosRoberto_D.pdf: 7798282 bytes, checksum: 043e551d51c3a8309982d9ff59835b10 (MD5) Previous issue date: 2014
Resumo: A via de sinalização da Calcineurina (Cn), uma fosfatase dependente de cálcio, desempenha papel chave no desenvolvimento, na hipertrofia e no remodelamento patológico do coração. A Calcineurina é negativamente regulada pelas Calsarcinas (CS), uma família de proteínas específicas do músculo estriado, que interagem diretamente com Cn. No entanto, os mecanismos moleculares de inibição de Cn por CS permanecem obscuros. Compreender a estrutura do complexo Cn:CS é fundamental para desvendar esse mecanismo de regulação. Neste trabalho foram combinados ensaios bioquímicos, crosslinking químico acoplado à Espectrometria de Massas (experimentos de MS / MS), análise mutacional e uma estratégia de modelagem computacional para a caracterização estrutural do complexo CnA:CS1 (isto é, constituído pela subunidade A de Cn e a isoforma 1 de CS, ambas murinas). O complexo recombinante foi submetido a crosslinking químico, tripsinizado e analisado por LC-MS/MS. Os dados obtidos foram utilizados em um docking in silico dos modelos de ambos os polipeptídeos, gerando várias poses para o complexo. As poses de menor energia de ligação foram agrupadas de acordo com semelhança estrutural e submetidas à simulação de dinâmica molecular. A superfície de interação identificada em CnA abrangeu as ?-hélices 1, 3 e loops vizinhos, enquanto a superfície correspondente de CS1 compreendeu os loops carboxiterminais das regiões Leu179-Phe185, Phe195-Ser199 e Thr250-Leu264. Notavelmente, a superfície de interação de CnA situa-se muito próxima à folha-? 14, o principal sítio de ligação do motivo PxIxIT do fator de transcrição NFAT, importante efetor da Calcineurina. Experimentos realizados com vários mutantes de CnA (FLAG- CnA) e CS1 (myc -CS1 ) foram utilizados para validar o modelo estrutural do complexo CnA:CS1. Os resíduos Lys40 (CnA) e Glu254 (CS1) foram identificados como críticos para a estabilidade do complexo. O modelo gerado neste estudo apoia a hipótese de que CS1 interage com um sítio alostérico para inibir a atividade de CnA
Abstract: Signaling by the calcium-dependent phosphatase calcineurin (Cn) plays key roles in regulating cardiac development, hypertrophy, and pathological remodeling. Cn binds to and is negatively regulated by calsarcins (CS), a family of muscle-specific proteins. However, the molecular mechanisms involved in the inhibition of Cn by CS remain unclear. Understanding the architecture and structure of Cn-CS complex is critical to unravel the regulation of Cn by CS. Here we combined biochemical assays, chemical crosslinking coupled to mass spectrometry experiments (MS/MS), mutational analysis and a modeling strategy for structural characterization of CnA-CS1 assembly. The MS/MS data obtained from the cross-linked peptides of both proteins were used to guide an in silico docking of their polypeptide models. The protein complex models with the smallest estimated binding energy were clustered according to structural similarity and submitted to molecular dynamics simulation. The interacting surface of CnA was mapped in a pocket between the 1st and 3rd ?-helixes and surrounding loops, while the corresponding surface of CS1 was mapped to the carboxyterminal loops within the Leu179-Phe185, Phe195-Ser199 and Thr250-Leu264 regions. Notably, the region of CnA that interacts with CS1 was found to be located in close proximity, but not coincident, to the ?-sheet 14, the main binding site for the PVIVIT sequence of NFAT. Experiments performed with several CnA (FLAG-CnA) and CS1 (myc-CS1) mutants were used to validate the structural model of the CnA-CS1 assembly. The Lys40 (CnA) and Glu254 (CS1) residues were identified as critical for the complex stability. The model that emerges from this study supports the notion that CS1 interacts with an allosteric site to inhibit the activity of CnA
Doutorado
Bioquimica
Doutor em Biologia Funcional e Molecular
21
Laudon, Hanna. "Functional domains in the Alzheimer's disease-associated presenilin 1 protein /." Stockholm, 2004. http://diss.kib.ki.se/2004/91-7140-085-0/.
Full text
22
Chan, Man Kid. "The interaction between Y box binding protein 1 and DNA replication proteins." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66802.
Full textAbstract:
A coordinated response to DNA damage is vital to maintain cellular viability and prevent the onset of disease. In mammalian cells, the intra-S phase checkpoint regulator, ATR (Ataxia-telangiectasia mutated and RAD3-related) kinase coordinates the response to DNA damage to ensure the genome is accurately and completely replicated before the cell enters mitosis. Y box Binding Protein 1 (YB-1), a transcription and translation factor, has previously been implicated in cell proliferation and the development of chemotherapeutic resistance. YB-1 has been linked to a wide variety of cellular stresses, but has not been studied in the context of DNA replication. In this study, we determined that YB-1 associates to both the β-globin replication origin (origin-containing) and the control (origin-lacking) DNA regions. This observation suggested that YB-1 may be involved in DNA replication elongation instead of initiation. By immunoprecipiating YB-1, we identified that PCNA and MCM7 preferentially interact with YB-1 during S phase. The examination of the spatial and temporal dynamics of these interactions by immunofluorescence microscopy, however, did not reveal nuclear colocalization of these proteins. By treating cells with hydroxyurea to stall the replication fork, we re-examined the protein-protein interaction between YB-1 and MCM7 and found that following 8 hours of hydroxyurea treatment, YB-1 and MCM7 exhibited diffuse colocalization in the cell nucleus. This finding may implicate YB-1 in exerting a late-onset response to prolonged replication fork arrest either directly at stalled replication forks or at "dormant" origins bound by MCM complexes. A number of roles for YB-1 can be postulated, such as the requirement of YB-1 in facilitating the resumption of DNA replication, or the activation of additional origins to duplicate the genome in the presence of a replication stress. This finding may in turn account foUne réponse coordonnée lors de dommages à l'ADN est vitale pour le maintien de la viabilité cellulaire et pour éviter l'installation de maladies. Dans les cellules de mammifères, le point de contrôle de la phase S, la protéine kinase ATR (Ataxia-telangiectasia mutated and RAD3-related), coordonne la réponse aux dommages de l'ADN afin d'assurer une réplication complète et fidèle du génome avant l'entrée en mitose. La protéine YB-1 (Y box Binding Protein 1), un facteur de transcription et de traduction, est impliqué dans la prolifération cellulaire et la résistance aux chimiothérapies. YB-1 est également lié à une large variété de stress cellulaires but aucune donnée n'est disponible quant à son rôle dans la réplication de l'ADN. Lors de mon travail de Master, j'ai pu montrer qu'YB-1 s'associe à la fois à l'origine de réplication de la β-globine et dans les régions contrôles de l'ADN. Ce résultat suggère qu'YB-1 pourrait être impliqué dans la phase d'élongation de la réplication de l'ADN plutôt que dans celui de l'initiation. Par immunoprécipitation, j'ai identifié PCNA et MCM7 comme interacteurs préférentiels d'YB-1 en phase S. Par contre, en immunofluorescence, je n'observe pas de colocalisation nucléaire entre ces protéines. Lors du blocage de la fourche de réplication par un traitement à l'hydroxyurée, l'interaction entre YB-1 et MCM7 a été réexaminée et j'ai mis en évidence que 8h après le traitement, ces deux protéines présentent une co-localisation diffuse dans le noyau. Ces données indiquent qu'YB-1 pourrait être impliqué dans une réponse tardive suite à un arrêt prolongé de la fourche de réplication soit directement au point d'arrêt soit au niveau d'origines « dormantes » liées aux complexes MCM. YB-1 peut donc avoir plusieurs rôles tels que l'aide à la reprise de la réplication de l'ADN ou l'activation d'origines de réplicatio
23
Begum, Rumena. "Kindlin-1 protein-protein interactions and functional relevance to Kindler syndrome." Thesis, King's College London (University of London), 2013. https://kclpure.kcl.ac.uk/portal/en/theses/kindlin1-proteinprotein-interactions-and-functional-relevance-to-kindler-syndrome(6c122016-c55d-4cbe-b4c3-99be4def7e9e).html.
Full textAbstract:
Kindler syndrome (KS) is an autosomal recessive genodermatosis resulting from pathogenic mutations in the FERMT1 (KIND) gene. This gene encodes kindlin-1 (also known as fermitin family homologue 1), a focal adhesion protein involved in activation of the integrin family of extracellular matrix receptors. Most cases of KS show a marked reduction or complete absence of the kindlin-1 protein in keratinocytes, resulting in defective integrin activation and abnormal cell adhesion and migration. However, currently very little is known about the way in which different FERMT1 mutations found in patients impact upon keratinocyte behaviour. The aim of this thesis is to screen for novel binding partners of kindlin-1 to elucidate possible new functions for this protein in epidermal cells. The main approaches taken were to assess differentially expressed proteins in normal vs. KS patient keratinocytes and also to use recombinant wild type and mutant kindlin-1 for pulldown assays to identify novel binding partners. Mass spectrometry analysis revealed a number of downregulated proteins in KS keratinocytes including epidermal growth factor receptor (EGFR) and thrombospondin-1 (TSP-1). Immunoblotting confirmed a significant reduction in both of these proteins. Further investigation showed changes in localisation of both TSP-1 and EGFR, and also defective signalling and response following EGF stimulation in KS keratinocytes. Moreover, EGFR levels in KS keratinocytes were partially restored following treatment with lysosomal inhibitors, suggesting that kindlin-1 can regulate the recycling of this receptor. Mass spectrometry analysis also identified the potential interaction partners of kindlin-1 to be talin and integrin linked kinase (ILK). Biochemical analysis revealed that kindlin-1 interacts specifically with the talin head domain. This interaction was significantly reduced with a mutant form of kindlin-1 dentified in a KS patient that lacks part of the F3 subdomain. Taken together, these studies have identified novel proteins that are regulated by kindlin-1 and may be important regulators of keratinocyte adhesion and migration.
24
Bain, Sharon Joanne Macnab. "Analysis of protein-protein interactions in the shell of herpes simplex virus type 1 (HSV-1) capsids." Thesis, University of Glasgow, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301830.
Full text
25
Méndez, Vidal Cristina. "Molecular studies of WIG-1, A P53-induced zinc finger protein /." Stockholm, 2003. http://diss.kib.ki.se/2003/91-7349-732-0.
Full text
26
Topping, Ryan. "Quantitative methods for reconstructing protein-protein interaction histories." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/14618.
Full textAbstract:
Protein-protein interactions (PPIs) are vital for the function of a cell and the evolution of these interactions produce much of the evolution of phenotype of an organism. However, as the evolutionary process cannot be observed, methods are required to infer evolution from existing data. An understanding of the resulting evolutionary relationships between species can then provide information for PPI prediction and function assignment. This thesis further develops and applies the interaction tree method for modelling PPI evolution within and between protein families. In this approach, a phylogeny of the protein family/ies of interest is used to explicitly construct a history of duplication and specification events. Given a model relating sequence change in this phylogeny to the probability of a rewiring event occurring, this method can then infer probabilities of interaction between the ancestral proteins described in the phylogeny. It is shown that the method can be adapted to infer the evolution of PPIs within obligate protein complexes, using a large set of such complexes to validate this application. This approach is then applied to reconstruct the history of the proteasome complex, using x-ray crystallography structures of the complex as input, with validation to show its utility in predicting present day complexes for which we have no structural data. The methodology is then adapted for application to transient PPIs. It is shown that the approach used in the previous chapter is inadequate here and a new scoring system is described based on a likelihood score of interaction. The predictive ability of this score is shown in predicting known two component systems in bacteria and its use in an interaction tree setting is demonstrated through inference of the interaction history between the histidine kinase and response regulator proteins responsible for sporulation onset in a set of bacteria. This thesis demonstrates that with suitable modifications the interaction tree approach is widely applicable to modelling PPI evolution and also, importantly, predicting existing PPIs. This demonstrates the need to incorporate phylogenetic data in to methods of predicting PPIs and gives some measure of the benefit in doing so.
27
Bane, Steven Edward. "Expression and characterization of the human neurokinin 1 receptor from Escherichia coli." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 99 p, 2007. http://proquest.umi.com/pqdweb?did=1342742951&sid=1&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Full text
28
Boutell, Christopher John. "Characterisation of the herpes simplex virus type 1 (HSV-1) triplex proteins." Thesis, University of Glasgow, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326428.
Full text
29
Chernov, Konstantin Grigorievich. "Interplay of YB-1 between tubulin and mRNA." Thesis, Evry-Val d'Essonne, 2008. http://www.theses.fr/2008EVRY0040/document.
Full textAbstract:
YB-1 est un régulateur important de l’expression des gènes dans les cellules eucaryotes. En plus de son rôle dans la transcription, YB-1 joue un rôle clé dans la traduction et la stabilisation des ARN messagers. Nous avons identifié plusieurs nouveaux partenaires de la protéine YB-1 par chromatographie d’affinité à partir de différents extraits tissulaires. Parmi ces partenaires, nous avons démontré que YB-1 interagit avec la tubuline et les microtubules et stimule fortement l'assemblage des microtubules in vitro. Les microtubules assemblés en présence de YB-1 ont une ultrastructure normale, et les données montrent que YB-1 recouvre probablement la surface extérieure des microtubules. De la même façon YB-1 stimule aussi l'assemblage de la tubuline-MAP qui est plus proche des complexes protéiques qui existent dans la cellule, et de la tubuline clivée par subtilisine ce qui suggère que son interaction avec la tubuline ne relève pas seulement d’effets électrostatiques. Nous avons enfin découvert que la tubuline interfère avec la formation des complexes ARNm:YB-1. Ces résultats suggèrent que YB-1 peut réguler l'assemblage des microtubules in vivo et que son interaction avec la tubuline peut contribuer à la régulation de la traduction des ARN messagers. En effet, in vivo, la traduction des mRNPs dépend de l’état de saturation de l’ARN messager par YB-1. Nous avons montré ici que lorsque le rapport YB-1:ARNm est faible, les complexes mRNPs possèdent des structures non-compactes, alors que les mRNPs saturés sont compacts. Ce changement structural est observé de façon parallèle à l'inhibition de la traduction des ARN messagers lorsqu’ils passent des polysomes (traduits) aux mRNPs libres (non traduits). De façon intéressante, nous avons découvert que les mRNPs saturés se lient aux microtubules via des interactions protéine:protéine et ont tendance à former des agrégats sur la surface des microtubules. Cette dernière propriété pourrait contribuer à la formation de granules de stress et à la localisation des mRNPs dans le cytoplasme. Finalement, un modèle de diffusion facilité a été développé pour expliquer l'assemblage des microtubules orchestré par les polyamines naturelles (telles que YB-1 qui sont positivement chargées dans la cellules). L’ensemble de ces données contribuent à une meilleure compréhension de processus biologiques fondamentaux concernant l’assemblage de la tubuline en microtubules et le trafic des ARN dans la cellule. Ils pourraient avoir un intérêt pour développer de nouveaux médicaments qui ciblent les microtubulesYB-1 is a major regulator of gene expression in eukaryotic cells. In addition to its role in transcription, YB-1 plays a key role in translation and stabilization of mRNAs. We identify several novels YB-1 protein partners by affinity chromatography of different tissue extracts. We observed that YB-1 interacts with tubulin and microtubules and stimulates microtubule assembly in vitro. Microtubules assembled in the presence of YB-1 exhibited a normal single wall ultrastructure where YB-1 probably coats the outer microtubule wall. Furthermore, we found that YB-1 also promotes the assembly of MAPs-tubulin and subtilisin-treated tubulin. Additionally, we demonstrated that tubulin interferes with mRNA:YB-1 complexes. These results suggest that YB-1 may regulate microtubule assembly in vivo and that its interaction with tubulin may contribute to the control of mRNA translation. The translational status of mRNPs in vivo depends on amount of YB-1 associated with mRNA. We show here that at low YB-1:mRNA ratios mRNP complexes possess an incompact structures, whereas saturated mRNPs are compact. This structural change corresponds to translation inhibition when mRNA moves from polysomal (translatable) to free (untranslatable) mRNPs. Saturated mRNPs bind to microtubules via protein:protein interactions and tend to self-aggregate on microtubule surface. This property could contribute to stress granule formation, mRNPs traffic and localization of translation apparatus within cytoplasm. Finally, the facilitated diffusion model was developed to explain enhancement of microtubule assembly by positively charged natural polyamines in living cells. Altogether our data contribute to the understanding of fundamental biological processes
30
Aviat, Florence. "Étude d'une protéine de leptospires : Hemolysis Associated Protein 1 : Hap 1." Nantes, 2006. http://www.theses.fr/2006NANT2012.
Full textAbstract:
La leptospirose est une zoonose de représentation mondiale concernant la plupart des Mammifères dont l'homme. Hap1 a été purifiée dans une fraction protéique de 32 kDa extraite de leptospires, bactéries responsables de la leptospirose. La protéine Hap1 s'est révélée être associée à une protection hétérologue contre la leptospirose chez des gerbilles. Le gène hap1 a été exprimé par E. Coli afin de produire la protéine recombinante rHap1. Ce travail confirme et prolonge les travaux antérieurs : Hap1 est secrétée par les seuls leptospires pathogènes lors de leur multiplication. Très immunogène et protectrice dans les conditions naturelles, cette protéine sous sa forme recombinante ne permet pas de reproduire les activités protectrices dans les conditions naturelles. L'objectif de ce travail était donc de purifier la ou les formes naturelles de la protéine Hap1 afin d'en définir les présentations structurales expliquant cette contradictionLeptospirosis is a zoonosis with a worldwide distribution concerning most Mammalians among which humans. Hap1 was purified from an antigenic zone with an apparent molecular mass of 32 kDa extracted from leptospires, bacteria responsible for leptospirosis. Immunization with Hap1 expressed by adenovirus or plasmid induced in gerbils a protection against leptospirosis. Then hap1 gene was expressed by E. Coli to product the recombinant protein rHap. This present work confirms these previous data: Hap1 is secreted during the multiplication of only pathogenic leptospires. Very immunogenic and protective in the natural conditions, this protein in the recombinant form doesn't permit to reproduce protective activity in the natural conditions. So, the purpose of this work was to purify one or many Hap1 naturally forms in order to determine the structural difference to understand this contradiction
31
McCready, Tara Lyn. "Inhibition of protein phosphatase-1 by endogenous inhibitor proteins and natural product toxins." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0032/NQ46885.pdf.
Full text
32
LOBO, DENISE DA SILVEIRA. "PROTEIN-PROTEIN INTERACTION ANALYSIS OF THE DEFENSIN PSD1 FROM PISUM SATIVUM WITH NEUROSPORA CRASSA PROTEINS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2006. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=9447@1.
Full textAbstract:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRODefensinas de planta, componentes inatos do sistema imune das plantas, são peptídeos antifúngicos, catiônicos, com estrutura primária rica em cisteína. Evidência dada pela literatura demonstrou que trechos de esfingolipídios complexos na membrana dos fungos, contendo manosildiinositolfosforilceramida e glicosilceramida, são sítios de ligação seletivos para as defensinas de planta isoladas de Dahlia merckii e Raphanus sativus, respectivamente. Entretanto, desconhece-se se as defensinas de planta interagem direta ou indiretamente com alvos intracelulares dos fungos. A fim de identificar interações físicas e diretas do tipo proteína- proteína, um sistema de duplo-híbrido, em levedura, baseado no fator de transcrição GAL4, foi construído utilizando-se como isca, a defensina da planta Pisum sativum, Psd1 (Pisum sativum defensin 1). Proteínas alvos, capazes de interagirem com o peptídeo Psd1, foram detectadas através do rastreamento de uma biblioteca de cDNA do fungo Neurospora crassa. Do resultado deste rastreamento, nove dentre quinze candidatos, selecionados pelo método do duplo-híbrido, foram identificados como proteínas nucleares da N. crassa. Um clone, detectado com alta freqüência neste rastreamento, apresentou homologia de seqüência com a proteína ciclina F, relacionada com o controle do ciclo celular. O ensaio de co-purificação utilizando a proteína conjugada a glutationa S-transferase (GST) validou in vitro o resultado obtido pelo sistema duplohíbrido. Análise por microscopia de fluorescência da Psd1, conjugada a FITC, e, dos núcleos do fungo Fusarium solani, marcados com DAPI, demonstrou in vivo a co-localização da defensina de planta Psd1 com os núcleos do fungo. Para pesquisar o modo de ação da Psd1 ao nível do ciclo celular, utilizou-se o modelo multicelular da retina de ratos neonatais, em desenvolvimento. Neste modelo, a migração nuclear intercinética, correlacionada com as transições de fase de S para M do ciclo celular, foi observada na presença da Psd1. Verificouse que Psd1 impediu a migração nuclear em neuroblastos, parando o ciclo celular na transição de S para G2. Estes resultados revelaram modos de ação da defensina de planta Psd1 sobre a fisiologia nuclear.
Plant defensins, innate components of the plant immune system, are cationic, antifungal peptides, with a cysteine- rich primary structure. Evidence from the literature demonstrated that fungus membrane patches containing complex sphingolipids, mannosyldiinositolphosphorylceramide and glucosylceramides, are selective binding sites for the plant defensins isolated from Dahlia merckii and Raphanus sativus, respectively. However, whether the plant defensins interact directly or indirectly with fungus intracellular targets is unknown. To identify direct physical protein-protein interactions, a GAL4-based yeast two-hybrid system was constructed, using the plant peptide, Pisum sativum defensin 1 (Psd1), as the bait protein. Target proteins, capable of interacting with the bait Psd1, were detected by screening a Neurospora crassa cDNA library. In this screening, nine out of fifteen two-hybrid candidates were identified as N. crassa nuclear proteins. One clone, detected with high frequency in the screening, presented sequence similarity to a N. crassa cyclin F, related to the cell cycle control. The GST pull- down co purification assay corroborated this two-hybrid result in vitro. Fluorescence microscopy analysis of FITC- conjugated Psd1 and DAPI-stained Fusarium solani nuclei demonstrated in vivo the co-localization of the plant peptide Psd1 and the fungus nuclei. We used the developing retina of neonatal rats as a multicellular model to study Psd1 mode of action at the cell cycle level. In this model, we observed in vivo the interkinetic nuclear migration, correlated to the transitions from S to M-phase of the cell cycle, in the presence of the Psd1 peptide. It was shown that Psd1 impaired nuclear migration of neuroblasts by arresting the cell cycle at the S to G2- phase transition. These results revealed modes of action of the plant defensin Psd1 upon the nuclear physiology.
33
McLaren, Lorna J. "The mouse protein phosphatase inhibitor-1 gene." Thesis, University of Edinburgh, 2001. http://hdl.handle.net/1842/24958.
Full textAbstract:
Intracellular proteins are phosphorylated by kinases and dephosphorylated by phosphatases. Protein phosphatase inhibitor-1 (I-1) inhibits protein phosphatase-1 (PP-1), thereby increasing the phosphorylated state of proteins in the cell. The initial aim of the work reported here was to determine whether I-1 is a kidney 'stem' cell marker (Svennilson et al., 1995); if so, it would be the first unique marker for these cells. The project involved characterizing the protein coding region of the mouse I-1 gene, determining the I-1 protein expression pattern in the developing mouse embryo and analysing potential promoter elements of the I-1 gene. A mouse genomic library was screened using a mouse cDNA clone homologous to the published rat I-1 mRNA and two types of clones with positive sequence homology to the rat mRNA sequence were isolated. These overlapping clones were sequenced, and analysis showed that the predicted mRNA and protein sequences contain 513 nucleotides and 171 amino acids, respectively, with both sharing over 95% homology with the known rat sequences. Further comparison of the predicted mouse protein I-1 sequence to those of rabbit, rat and human showed that there is strong homology across species, and that all share motifs which are important for inhibiting PP-1 (a KIQF sequence at amino acid positions 9-12 and a threonine at position 35). The mouse I-1 gene contains seven protein-coding exons which lie in a 7 kb region of DNA on chromosome 15, band F. Svennilson et al. (1995) detected I-1 expression in peripheral metanephric mesenchyme (nephron progenitor) cells in rate sections using RNA in situ hibridization. With this in mind, the mouse protein expression pattern was determined using wholemount tissue, a commercially available anti-I-1 antibody and fluorescent confocal microscopy. The results showed that I-1 is not a 'stem' cell marker in the developing kidney, but is restricted to the peripheral epithelial layer of cells of the kidney i.e. the mesothelium.
34
Jesus, João André Fernandes de. "Aß effects in protein phosphatase 1 complexes." Master's thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/21535.
Full textAbstract:
Mestrado em Biomedicina MolecularThe brain is a complex structure, which is comprised by neurons capable of communication through synapses. These usually occur between an axon terminal and a dendritic spine of different neurons. The dendritic spines are dynamic structures that allow for a rapid adaptation to different stimuli. PP1 is a phosphatase protein that catalyses the majority of dephosphorylation reactions in the human body. It has different functions that vary, from glycogen metabolism to synaptic regulation. Neurabins (1 and 2) are two PP1 regulator subunits that are structurally and functionally similar to each other. They are highly enriched in the dendritic spines, interacting with several proteins, including PP1, and targeting them to receptors, cytoskeleton or other cellular compartments. Thus, regulating neuronal morphology and synaptic transmission and plasticity. Phactr3 belongs to the actin regulatory protein family, which comprises four members. Phactr3 is involved in cell migration and regulates cytoskeleton dynamics. It interacts with PP1 forming a complex that is controlled by changes in cytoplasmic G-actin concentration, thus, regulating actin cytoskeleton dynamics. Neurodegenerative diseases are usually characterised by the loss of synapses, neural death, gradual loss of cognitive functions and memory. It is believed that Aβ is the major culprit in these changes. Aβ results from an abnormal cleavage of APP, via the amyloidogenic pathway, resulting in the overproduction of toxic peptides. The main aim of this thesis was to evaluate the effects of Aβ on Neurabins and Phactr3 expression, and in PP1 complexes. The results show a slight decrease in neurabins’ expression, and a slight increase in Phactr3 expression. The results also show a decrease in interaction between PP1 and Neurabin-1, possibly due to direct effect of Aβ on Neurabin-1 or the imbalance of phosphatases and kinases, and between PP1 and Phactr3, possibly due to variations of G-actin levels which competes with PP1 to binding with Phactr3. The same changes were not observed in Neurabin-2/PP1 complexes. A possible explanation is that both are differently regulated by several kinases. The results allow us to conclude that Aβ interferes in the expression of all three proteins and in the interaction of Neurabin-1/PP1. However, additional studies are required in order to better understand the physiological relevance of these complexes.
O cérebro é uma estrutura complexa, que é composta por neurónios capazes de comunicar através de sinapses. Estas normalmente ocorrem entre um terminal axónico e espinha dendritica de neurónios diferentes. As espinhas dendriticas são estruturas dinâmicas que permitem uma rápida adaptação a diferentes estímulos. A PP1 é uma proteína fosfatase que catalisa a maioria das desfosforilações que ocorrem no corpo humano. Tem diversas funções, que variam desde metabolismo de glicogénio a regulação sináptica. As neurorabinas (1 e 2) são duas subunidades reguladores da PP1 que são estruturalmente e funcionalmente idênticas entre si. São muito enriquecidas nas espinhas dendriticas e interagem com diversas proteínas, incluindo a PP1, e guiam as proteínas para receptores, citoesqueleto ou outros compartimentos celulares, regulando assim a morfologia neuronal e transmissão e plasticidade sináptica. A Phactr3 pertence à família de proteínas reguladoras de actina, á qual pertencem quatro membros. A Phactr3 está envolvida na migração celular e regula a dinâmica do citoesqueleto. Interage com a PP1, formando um complexo que é controlado por alterações na concentração de G-actina citoplasmática, regulando assim a dinâmica do citoesqueleto. Doenças neurodegenerativas, são normalmente caracterizadas pela perda de sinapses, morte neuronal, e perda gradual de funções cognitivas e memória. Acredita-se que o principal fator responsável por essas anomalias seja o péptido Aβ. Este resulta de uma clivagem anormal de APP, pela via amiloidogénica, resultando numa sobreprodução do péptido tóxico. O objectivo desta tese era avaliar os efeitos de Aβ nos níveis de expressão das neurorabinas e Phactr3, assim como os complexos formados com a PP1. Os resultados mostram uma ligeira diminuição nos níveis de expressão das neurorabinas, e num ligeiro aumento na expressão de Phactr3. Os resultados também mostram uma diminuição na interação do complexo Neurorabina-1/PP1, provavelmente devido a um efeito direto de Aβ sobre Neurorabina-1 ou um desequilíbrio nas fosfatases e cinases, e Phactr3/PP1, provavelmente devido a variação nos níveis de G-actina, que compete com a PP1 para interagir com Phactr3. As mesmas alterações não foram verificadas no complexo Neurorabina-2/PP1. Uma explicação possível é que ambas as proteínas são reguladas de forma diferente por diversas cinases. Estes resultados permitem concluir que Aβ interfere na expressão das três proteínas e nos níveis de interação de Neurabina-1/PP1 e Phactr3/PP1. No entanto são necessários mais estudos para obter uma melhor compreensão da relevância fisiológica destes complexos.
35
Wallach, Thomas. "A dynamic circadian protein-protein interaction network." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2012. http://dx.doi.org/10.18452/16604.
Full textAbstract:
Die dynamische Regulation von Protein-Protein Interaktionen (PPIs) ist wichtig für den Ablauf von biologischen Prozessen. Die circadiane Uhr, die einen ~24 Stunden Rhythmus generiert und eine Vielzahl von physiologischen Parametern steuert kann auch die Dynamik von PPIs regulieren. Um neue Erkenntnisse über regulatorische Mechanismen innerhalb des molekularen Oszillators zu gewinnen, habe ich zunächst alle möglichen PPIs zwischen 46 circadianen Komponenten mittels eines systematischen yeast-two-hybid (Y2H) Screens bestimmt. Dabei habe ich 109 bis dahin noch unbekannte PPIs identifiziert und einen repräsentativen Anteil mittels Co-Immunopräzipitationsexperimenten in humanen Zellen validiert. Unter den neuen PPIs habe ich bis dahin unbekannte Modulatoren der CLOCK/BMAL1 Transaktivierung identifiziert und dabei die Rolle der Proteinphosphatase 1 (PP1) als dynamischen Regulator der BMAL1 Stabilität funktionell charakterisiert. Das experimentelle PPI Netzwerk wurde mit bereits aus der Literatur bekannten PPIs und Interaktionspartnern ergänzt. Eine systematische RNAi Studie belegte außerdem die Relevanz der aus der Literatur stammenden Interaktoren für die ~24 Stunden Periodizität. Um eine Aussage über die Dynamik der PPIs im Netzwerk treffen zu können, wurden circadiane mRNA Expressionsdaten in das PPI Netzwerk integriert. Systematische Perturbationsstudien, in denen alle Komponenten des experimentellen Netzwerkes mittels RNAi herunterreguliert oder überexprimiert wurden, zeigten eine essentielle Bedeutung für die dynamischen PPIs innerhalb des circadianen Oszillators auf. Desweiteren wurden im circadianen PPI Netzwerk funktionelle Module identifiziert, welche dynamisch organsiert sind. Durch eine systemweite Analyse des humanen Proteoms wurden viele dynamische PPIs identifiziert, die biologische Prozesse wie z.B. Signaltransduktion und Zellzyklus miteinander verbinden. Rhythmische PPIs sind daher von Bedeutung für die zeitliche Organisation zellulärer Physiologie.Essentially all biological processes depend on protein-protein interactions (PPIs). Timing of such interactions is crucial for regulatory function. Although circadian (~24 hrs) clocks constitute fundamental cellular timing mechanisms regulating important physiological processes PPI dynamics on this timescale are largely unknown. To elucidate so far unknown regulatory mechanisms within the circadian clockwork, I have systematically mapped PPIs among 46 circadian components using high-throughput yeast-two-hybrid (Y2H) interaction experiments. I have identified 109 so far uncharacterized interactions and successfully validated a sub-fraction via co-immunoprecipitation experiments in human cells. Among the novel PPIs, I have identified modulators of CLOCK/BMAL1 function and further characterized the role of protein phosphatase 1 (PP1) in the dynamic regulation of BMAL1 abundance. Furthermore, to generate a more comprehensive circadian PPI network, the experimental network was enriched and extended with additional interactions and interaction partners from literature, some of which turned out to be essential for normal circadian dynamics. The integration of circadian mRNA expression profiles allowed us to determine the interaction dynamics within our network. Systematic genetic perturbation studies (RNAi and overexpression in oscillating human cells) revealed a crucial role of dynamic regulation (via rhythmic PPIs) for the molecular clockwork. Furthermore, dynamic modular organization as a pervasive circadian network feature likely contributes to time-of-day dependent control of many cellular processes. Global analysis of the proteome regarding circadian regulation of biological processes via rhythmic PPIs revealed time-of-day dependent organization of the human interactome. Circadian PPIs dynamically connect many important cellular processes like signal transduction and cell cycle, which contribute to temporal organization of cellular physiology.
36
Turner, Kendrick Bruce. "CELL AND PROTEIN-BASED SENSING SYSTEMS FOR THE DETECTION OF ENVIRONMENTALLY AND PHYSIOLOGICALLY RELEVANT MOLECULES." UKnowledge, 2011. http://uknowledge.uky.edu/chemistry_etds/1.
Full textAbstract:
The detection of small molecules in complex sample matrices such as environmental (surface and ground water, sediment, etc.) and biological (blood, serum, plasma, etc.) samples is of paramount importance for monitoring the distribution of environmental pollutants and their patterns of exposure within the population as well as diagnosing and managing diseases. Biosensors have demonstrated a singular ability to sensitively and selectively detect analytes in complex samples without the need for extensive sample preparation and pretreatment. Nature has demonstrated myriad examples of exquisite selectivity in spite of complexity and we seek to take advantage of that attribute in the development of novel biosensing systems.
In the work presented here, we have developed both cell- and proteinbased biosensing systems for the detection of hydroxylated polychlorinated biphenyls (OH-PCBs) and protein-based sensing systems for the detection of glucose. In the development of a whole-cell sensing system, the regulatory protein, HbpR, and its associated promoter was used to modulate the expression of luciferase. Additionally, the effector binding domain of HbpR, HbpR-A, was isolated and modified with a solvatochromic fluorophore resulting in a proteinbased sensing system. For the detection of glucose, two different glucose binding proteins were engineered in an effort to tailor their characteristics, such as binding affinity and thermal stability, to develop a rugged, sensitive proteinbased sensing system. We envision that these biosensing systems will find applications in the areas of environmental pollutant monitoring and the management and treatment of diseases such as diabetes.
37
Hill, Donna Monique. "Mechanism of centaurin-alpha-1 control of neuronal differentiation." Birmingham, Ala. : University of Alabama at Birmingham, 2010. https://www.mhsl.uab.edu/dt/2010m/hill.pdf.
Full textAbstract:
Thesis (M.S.)--University of Alabama at Birmingham, 2009.Title from PDF t.p. (viewed June 30, 2010). Additional advisors: Lori McMahon, Stephen Watts. Includes bibliographical references (p. 31-35).
38
Wang, Shu-Zong. "Cloning and characterization of SAPK interacting protein 1 (SIN1), a type 1 IFN receptor subunit 2 (IFNAR2)-interacting protein /." Free to MU Campus, others may purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p3137761.
Full text
39
Smith, Lucy. "Investigating inhibitors of the IgE:high affinity receptor protein-protein interaction." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/44210.
Full textAbstract:
The protein-protein interaction (PPI) between immunoglobulin E (IgE) and its high affinity receptor (FcεRI) is an important part of the allergic response. Inhibition of the IgE:FcεRI interaction is a key strategy for the development of allergy treatments. This PPI has been validated as a therapeutic target by the humanised monoclonal antibody omalizumab, which binds to IgE and prevents the formation of the IgE:FcεRI complex and has proved successful at treating allergic asthma. However, small molecule inhibitors of the IgE:FcεRI PPI that are orally available would be a more desirable form of treatment. This thesis describes the design, synthesis and testing of two series of inhibitors of the IgE:FcεRI interaction; small molecules based on the natural product aspercyclide A and short, linear peptides based on a key binding epitope of FcεRI. It also describes the development of a high-throughput time resolved fluorescence resonance energy transfer (TR-FRET) assay to test inhibitors and subsequent X-ray crystallography and SPR experiments to further investigate the mode of action of the inhibitors. An analogue of aspercyclide A has shown inhibition of the IgE:FcεRI interaction in the micromolar range and an improved potency compared to the natural product itself. A number of 8-residue, linear peptides have been found to inhibit the IgE:FcεRI PPI in the micromolar range when tested in the TR-FRET assay. The most potent peptide has been biotinylated and immobilised for SPR experiments with IgE and FcεRI. These SPR experiments suggest that the peptide inhibits the IgE:FcεRI interaction by binding to the high affinity receptor rather than to IgE.
40
Astanehe, Arezoo. "Role of Y-box binding protein-1 (YB-1) in breast cancer." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/36668.
Full textAbstract:
The Y-box binding protein-1 (YB-1) is a multifunctional protein with roles in transcription, translation, DNA repair, and a recently identified function as an extracellular mitogen. YB-1 is over-expressed in various malignancies including breast carcinoma. Previous work from our laboratory has shown that YB-1 is expressed in approximately 40% of invasive breast carcinomas, and its expression correlates with relapse and poor survival. Further, the oncogenic potential of YB-1 has been demonstrated in breast cancer. In the studies presented in this thesis, we sought to understand the contribution of YB-1 as an oncogenic transcription factor to breast cancer. We focused our studies on the basal-like breast carcinoma (BLBC) and the human epidermal growth factor receptor 2 (HER2) over-expressing breast cancers, as patients with these subtypes suffer the worst prognosis. Using BLBC cell lines, we demonstrated that YB-1 induces expression of MET and PIK3CA to promote anchorage-independent growth and invasion respectively. These studies further identified YB-1 as a potential therapeutic target in BLBC. We then directed our focus to the HER2 over-expressing breast cancers. Although the development of trastuzumab (Herceptin®), a targeted therapy against HER2, has provided a substantial advance in the care of affected patients, resistance remains a prevailing challenge. We identified a novel mechanism by which signalling proteins, mitogen activated protein kinase interacting kinase (MNK) and p90 ribosomal S6 kinase (RSK), interact to increase phosphorylation of YB-1. In turn, phosphorylation of YB-1 promotes its nuclear translocation where it regulates transcription of genes involved in trastuzumab resistance. These results further suggest YB-1 as a therapeutic target to improve outcome for women with trastuzumab refractory disease. As a whole, the studies outlined in this thesis have contributed to our understanding of breast cancer pathogenesis and have identified novel aspects of YB-1 function in BLBC and in HER2 over-expressing breast carcinomas.
41
Dawson, John Francis. "The regulation of protein phosphatase-1 by reversible protein phosphorylation and marine toxins." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ34753.pdf.
Full text
42
Kilisch, Markus. "Quantitative analysis of protein-protein interactions governing TASK-1/TASK-3 intracellular transport." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2016. http://hdl.handle.net/11858/00-1735-0000-0028-87D8-0.
Full text
43
Tian, Wang, la Vega Montserrat Rojo de, Cody J. Schmidlin, Aikseng Ooi, and Donna D. Zhang. "Kelch-like ECH-associated protein 1 (KEAP1) differentially regulates nuclear factor erythroid-2–related factors 1 and 2 (NRF1 and NRF2)." AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, 2018. http://hdl.handle.net/10150/627124.
Full textAbstract:
Nuclear factor erythroid-2-related factor 1 (NRF1) and NRF2 are essential for maintaining redox homeostasis and coordinating cellular stress responses. They are highly homologous transcription factors that regulate the expression of genes bearing antioxidant-response elements (AREs). Genetic ablation of NRF1 or NRF2 results in vastly different phenotypic outcomes, implying that they play different roles and may be differentially regulated. Kelch-like ECH-associated protein 1 (KEAP1) is the main negative regulator of NRF2 and mediates ubiquitylation and degradation of NRF2 through its NRF2-ECH homology-like domain 2 (Neh2). Here, we report that KEAP1 binds to the Neh2-like (Neh2L) domain of NRF1 and stabilizes it. Consistently, NRF1 is more stable in KEAP1(+/+) than in KEAP1(-/-) isogenic cell lines, whereas NRF2 is dramatically stabilized in KEAP1(-/-) cells. Replacing NRF1's Neh2L domain with NRF2's Neh2 domain renders NRF1 sensitive to KEAP1-mediated degradation, indicating that the amino acids between the DLG and ETGE motifs, not just the motifs themselves, are essential for KEAP1-mediated degradation. Systematic site-directed mutagenesis identified the core amino acid residues required for KEAP1-mediated degradation and further indicated that the DLG and ETGE motifs with correct spacing are insufficient as a KEAP1 degron. Our results offer critical insights into our understanding of the differential regulation of NRF1 and NRF2 by KEAP1 and their different physiological roles.
44
Wadd, Sarah. "Identification of the cellular proteins which interact with the essential HSV-1 protein IE63." Thesis, University of Glasgow, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323269.
Full text
45
Bradshaw, Richard Thomas. "Predicting structural and energetic effects of mutations at protein-protein interfaces." Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/17988.
Full textAbstract:
Understanding the structural, dynamical and energetic basis of protein-protein interactions (PPIs) is key for a number of research disciplines. Predicting which sites in PPIs show potential for modulation with binding free energy (ΔG) calculations allows experimental work to be targeted and inhibitors to be rationally designed. However, PPIs remain a challenging target for computational free energy calculations due to their large and complex interfaces. A number of different methods for predicting ΔG from molecular dynamics simulations have been developed, yet each suffers from unique problems in its potential for widespread implementation across PPIs. This thesis initially evaluates the efficacy of the existing MM-PB/GBSA free energy calculation techniques and notes a niche for the improvement of the methods’ predictive power. This is followed by the development of a new computational method for predicting the effects of any PPI interface mutation, which we term Mutational Locally Enhanced Sampling (MULES). MULES generates atomistic molecular dynamics trajectories of native and mutant protein complexes simultaneously. These trajectories are then used to calculate relative binding free energies (ΔΔG) between the two complexes, investigating both structural and energetic effects of individual amino acids at an interface. In principle MULES allows the effect of any mutation to be calculated. Initially tested against a prototypical set of mutations with experimentally measured ΔΔG, MULES showed significantly improved accuracy in ΔΔG prediction and high precision and speed compared to existing methods. The approach was further validated on a large and diverse dataset of approximately 60 individual mutations, comparing results to experimental data and other computational predictions. Validation provided additional evidence for the improved accuracy, precision, speed and particularly versatility of the technique, but also identified areas for improvement. The successes and limitations of MULES discovered here will be of interest to the protein design, drug discovery and computational chemical biology communities.
46
Shurte, Leah A. "Determining Protein-Protein Interactions of ALS-Associated SOD1." Wright State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=wright1464283630.
Full text
47
Sidiqi, Mahjooba. "The structure and RNA-binding of poly (C) protein 1." University of Western Australia. School of Biomedical, Biomolecular and Chemical Sciences, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0077.
Full textAbstract:
[Truncated abstract] Regulation of mRNA stability is an important posttranscriptional mechanism involved in the control of gene expression. The rate of mRNA decay can differ greatly from one mRNA to another and may be regulated by RNA-protein interactions. A key determinant of mRNA decay are sequence instability (cis) elements often located in the 3' untranslated region (UTR) of many mRNAs. For example, the AU rich elements (AREs), are such well characterized elements, and most commonly involved in promoting mRNA degradation, and specific binding of proteins to these elements leading to the stabilization of some mRNAs. Other cis-elements have been described for mRNA in which mRNA stability is a critical component of gene regulation. This includes the androgen receptor (AR) UC-rich cis element in its 3'UTR. The AR is a key target for therapeutics in human prostate cancer and thus understanding the mechanism involved in regulating its expression is an important goal. The [alpha]CP1 protein, a KH-domain containing RNA-binding protein has been found to bind this UC-rich region of the AR and is thought to play an important role in regulating AR mRNA expression. [alpha]CP1 protein is a triple KH (hnRNP K homology) domain protein with specificity for Crich tracts of RNA and ssDNA (single stranded DNA). Relatively little is known about the structural interaction of [alpha]CP1 with target RNA cis elements, thus the present study aimed to better understand the nature of interaction between 30 nt 3'UTR UC-rich AR mRNA and [alpha]CP1 protein using various biophysical techniques, in an attempt to determine which [alpha]CP1 domain or combination of domains is involved in RNA-binding. These studies could ultimately provide novel targets for drugs aimed to regulate AR mRNA expression in prostate cancer cells. At the commencement of this study little was known about the structure of the [alpha]CP1- KH domains and their basis for poly (C) binding specificity. ... Additional studies addressed the significance of the four core recognition nucleotides (TCCC) using a series of cytosine to thymine mutants. The findings verified some of the results predicted from structural studies, especially the need for maximum KH binding to a core tetranucleotide recognition sequence. Our mutational studies of the four core bases confirmed the importance of cytosine in positions two and three as no binding was observed, while some binding was observed when the fourth base was mutated. In summary, the work presented in this thesis provides new detailed insight into the molecular interactions between the [alpha]CP1-KH domain and AR mRNA. Furthermore, these studies shed light on the nature of protein/mRNA interactions in general, as well as the specific complex that forms on AR mRNA. These studies have provided new understanding into the mode of [alpha]CP1 binding at a target oligonucleotide binding site and, provide a foundation for future studies to define structure of multiprotein/oligonucleotide complexes involved in AR mRNA gene regulation. Understanding the detailed interaction between the AR mRNA and [alpha]CP1 could provide possible targets for drug development at reducing AR expression in prostate cancer cells by interfering with the interaction of [alpha]CP1 and AR-mRNA.
48
Schwartz, Christine. "Muscle LIM protein and Nesprin-1 in Mechanotransduction." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066374/document.
Full textAbstract:
J’ai étudié trois protéines qui participent à deux vois différentes de méchano-transduction qui est la conversion des stimuli physiques en un signal biochimique.Dans une culture cellulaire en 2D, lorsque les cardiomyocytes sont étirés, MLP est transloqué vers le noyau. Sans translocation, les cellules ne parviennent pas à répondre à la stimulation. Les patients porteurs de mutations dans MLP développent une cardiomyopathie comme les souris MLP knock-out (MLP-/-). Mon objectif a été d’élucider le rôle de MLP dans ces cardiomyopathies en surexprimant des mutations de MLP dans les cardiomyocytes isolés des souris MLP-/- néonataux. Dans les cultures 2D mais pas 3D, MLP n’était pas transloqué vers le noyau après l’étirement des cellules. Bien que je n’aie pas pu résoudre ce problème, j’ai mis au point les expériences nécessaires à la poursuite de ce projet.Nesprins s’intègrent dans un complexe transmembranaire de l’enveloppe nucléaire (EN), le LINC complexe, qui connecte le cytosquelette à l’intérieur du noyau. Les myoblastes isolés des patients porteurs des mutations de Nesprin ou de Lamin, qui est associé au LINC complexe, ont présenté des noyaux déformés ainsi que des anomalies de réponses méchanosensibles : Si cultivées sur supports mous, les cellules affichaient un niveau élevé de fibres musculaires stressées et d’adhésions focales. Le knock-down de FHOD, une cible en aval de ROCK et SRC, qui également étaient actives dans ces myoblastes, a réduit ce phénotype. Bien que l’on ait émis l’hypothèse que les mutations dans Nesprins et Lamins conduisent à une instabilité mécanique de l’EN, ces résultats indiquent que les voies de signalisation par l’EN sont perturbées aussiI studied three striated muscle proteins that are participating in two different pathways of mechanotransduction, which is the translation of a physical stimulus into a biochemical signal.When isolated cardiomyocytes are stretched in 2D, MLP shuttles to the nucleus. Without shuttling MLP, these cells fail to respond to the stretch stimulus. Human patients with MLP-mutations develop cardiomyopathies, as well as mice with a knock-out of MLP (MLP-/-). By expressing mutated MLP in neonatal cardiomyocytes of MLP-/- mice, I wanted to elucidate the role of mutant MLP. Surprisingly, MLP did shuttle after stretching of 2D but not 3D cell cultures. Although I could not solve this issue, I prepared the setup for subsequent experiments.Nesprins are part of the nuclear envelope (NE) spanning LINC complex, which connects the cytoskeleton with the nucleus. Myoblasts from patients with mutations in Nesprins or LINC-associated Lamins displayed deformed nuclei and had defects in mechanosensitive responses with an elevated level of stress fibers and focal adhesions on soft surfaces. This phenotype could be rescued by knock-down of formin FHOD1, a downstream target of ROCK and SRC, which also were highly active in the mutant cells. While mutations in Nesprins and Lamins are thought to lead to mechanical instability of the NE, these results indicate that signaling pathways through the NE are disturbed as well
49
Xu, Xiaodong. "Expression and characterization of HIV-1 envelope protein." Thesis, University of Reading, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500515.
Full textAbstract:
We postulated that gp120 and CD4 interaction might expose cryptic epitopes on gp120 that could be immunogenic and so widen the immunogenic response. A fusion protein of a C clade strain of HIV-1 (HIVCN54) gp120 and full-length human CD4 was constructed and expressed using a recombinant baculovirus system. The protein was purified, characterized and used to immunize rabbits. The antiserum generated had an expected anti-gp120 activity and demonstrated a higher capacity than a control serum raised to gp120 alone to block b12 binding, a marker of neutralization. A formal neutralization assay however did not detect neutralizing activity in the CD4-gp120CN54 antiserum. To enhance overall immunogenicity, a gp120CN54-FPV168 fusion protein was also expressed. FPV168 is a fowlpox virus protein. Although designed to elicit a stronger host immune response, the antiserum generated to gp120CN54-FPV168 had a weaker binding activity to gp120 than the antiserum generated to non-fused gp120CN54. A possible reason was protein instability associated with fusion to the N-terminus of FPV168. To ameliorate this problem, three gp120 fusion proteins with N-terminal truncated FPV168 were also constructed. The stability of these proteins was vastly improved but their performance as immunogens continued to be poorer than immunization with gp120 alone. Lastly, experiments describing an alternative strategy of immune enhancement based on targeting of gp120 or fragments of gp120 to antigen presenting cells via use of the human immunoglobulin Fc domain are presented. These were more successful and indicate a future direction that could yet produce an HIV-1 gp120 based immunogen capable of raising the antibody responses required as part of a successful vaccine.
50
Nicoli, Francesco. "Immunomodulatory properties of the HIV-1 Tat protein." Diss., Ludwig-Maximilians-Universität München, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:19-174938.
Full text