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Even, Yasmine. "Caractéristiques et fonctions d'une Cdk-like, CDC2L5." Paris 6, 2005. http://www.theses.fr/2005PA066136.
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Birot, Adrien. "Regulation of fission yeast cohesin by the Cyclin Dependent Kinase PeF1." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0386/document.
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Le complexe cohésine est un complexe protéique en forme d'anneau composé de quatre sous-unités essentielles très conservées: Smc1, Smc3, Rad21 et Scc3. Par sa capacité à encercler les molécules d’ADN, les cohésines participent à de nombreux processus cellulaires tels que la ségrégation des chromosomes, la signalisation et la réparation des dommages à l’ADN, la régulation de la transcription et l'organisation du génome. Pour assurer ces différentes fonctions biologiques les cohésines doivent être finement régulées à la fois dans le temps et l’espace. Ces régulations reposent en partie sur le contrôle de leur association à la chromatine (capture de l’ADN). Cela nécessite l'action d'un «facteur de chargement » composé de deux protéines conservées et essentielles, Mis4 et Ssl3 chez la levure S. pombe. Comment ce complexe régule la capture de l’ADN par l’anneau de cohésine dans l'espace et le temps demeure à ce jour très mal compris. Afin d’identifier des régulateurs de l’association des cohésines à la chromatine, nous avons réalisé un crible génétique visant à rechercher des suppresseurs de la mutation thermosensible mis4-367. Ce crible a conduit à l’identification de la Cyclin-Dependent Kinase Pef1 qui agit comme un régulateur négatif de la cohésion des chromatides soeurs en contrôlant vraisemblablement négativement l’association des cohésines à la chromatine. De forts arguments expérimentaux indiquent que Pef1 exerce sa fonction en régulant directement la phosphorylation de la sous-unité Rad21 du complexe cohésine. De façon intéressante, via un autre crible génétique, nous avons identifié la phosphatase Pph3/Psy2 qui joue un rôle dans l’établissement de la cohésion des chromatides soeurs en contrôlant la déphosphorylation de Rad21.Ensemble, ces données suggèrent que le contrôle de l’état de phosphorylation de la sous-unité Rad21 du complexe cohésine joue un rôle central dans le processus de cohésion chez la levure S. PombeCohesin is a highly conserved ring-shaped protein complex made of four essential subunits: Psm1, Psm3, Rad21 and Psc3. By its ability to capture DNA molecules within its ring-like structure, cohesion plays a key role in many cellular processes such as chromosome segregation, DNA damage signalling and repair, transcriptional gene regulation and nuclear organization. To ensure all of its biological functions, cohesin must be tightly regulated in space and time. This regulation relies in part on the control of cohesin binding to chromatin (DNA capture). Cohesin recruitment to chromatin requires the action of a “loading complex” made of two conserved and essential proteins named Mis4 and Ssl3 in the fission yeast. How this complex regulates where and when DNA capture by the cohesin ring must occur remains poorly understood. To identify regulators of cohesin binding to chromatin we have performed a genetic screen for suppressors of the thermosensitive mutation mis4-367. This genetic screen has led to the identification of the cyclin-dependent-kinase Pef1 that acts as a negative regulator of sister chromatids cohesion may be bynegatively controlling cohesin binding to chromatin. Strong experimental evidences indicate that Pef1 exerts its function at least in part by directly phosphorylating the Rad21 subunit of the cohesin complex. Interestingly, a genetic screen made in parallel identified the Pph3/Psy2 phosphatase as implicated in the establishment of sister chromatid cohesion by regulating Rad21 dephosphorylation. Strikingly, the control of Rad21 phosphorylation status appears central to the cohesion process in the fission yeast S. pombe
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Northen, Julian S. "Design of novel pyrimido[5,4-d]pyrimidine cyclin dependent kinase (cdk) inhibitors." Thesis, University of Newcastle Upon Tyne, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391320.
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Parsons, Rachel. "The design and synthesis of pyrimidine based cyclin-dependent kinase (CDK) inhibitors." Thesis, University of Newcastle Upon Tyne, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.408491.
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Bonnet, Christine. "Un motif sur la cycline B nécessaire à l'activation de CDK1 chez la levure ?" Paris 6, 2002. http://www.theses.fr/2002PA066509.
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Nafati, Mehdi. "Caractérisation fonctionnelle des inhibiteurs de Cyclin-Dependent Kinase (CDK) dans le fruit de tomate (Solanum lycopersicum)." Thesis, Bordeaux 2, 2010. http://www.theses.fr/2010BOR21712/document.
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Au sein de l’unité mixte de recherche 619 de l’Institut National de Recherche Agronomique, le groupe « Organogénèse du Fruit et Endoréduplication » étudie les acteurs moléculaires prenant part au contrôle du cycle cellulaire dans le fruit de tomate. L’objet de la présente thèse est l’étude de l’inhibiteur du cycle cellulaire Kip-Related Protein, et son rôle durant le développement du fruit. Identification de motifs protéiques fonctionnels chez l’Inhibiteur de Kinase Cycline-Dependent SlKRP1 chez Solanum lycopersicum : Leur rôle dans les interactions avec des partenaires du cycle cellulaire Les Kip-related proteins (KRPs) jouent un rôle majeur dans la régulation du cycle cellulaire. Il a été montré qu’ils inhibent les complexes CDK/Cyclin et ainsi bloquent la progression du cycle cellulaire. Malgré leur manque d’homologie avec leurs homologues animaux au delà de leur motif de liaison CDK/Cyclin, localisé à l’extrémité C-terminal de la protéine dans les séquences de plante, des études antérieurs ont montré la présence de motifs conservés spécifiques aux plantes chez certaines KRPs. Nous n’avons cependant que peu d’information concernant leur fonction. Nous montrons ici que les KRPs sont distribués en deux sous groupes phylogénétiques, et que chaque sous-groupe dispose de courts motifs spécifiques conservés. Les KRPs du sous-groupe 1 disposent ainsi de six motifs conservés entre eux. Utilisant SlKRP1, qui appartient au sous-groupe 1, nous avons identifié des motifs responsables de la localisation de la protéine et de ses interactions protéine-protéine. Nous montrons que le motif 2 est responsable de l’interaction avec CSN5, une sous-unité du complexe signalosome, et que le motif 5 a un effet redondant avec le motif 3 pour ce qui est de la localisation sub-cellulaire de la protéine. Nous montrons de plus que SlKRP1 est capable de guider SlCDKA1 et SlCycD3;1 vers le noyau, et ce même en l’absence du motif de liaison CDK/Cycline précédemment référencé. Ce nouveau site d’interaction est probablement localisé dans la partie centrale de la séquence de SlKRP1. Ces résultats apportent de nouveaux indices quant au rôle de la partie encore méconnue de cette protéine. La surexpression de SlKRP1 dans le mésocarpe de tomate détruit la proportionnalité entre endoréduplication et taille cellulaire Le fruit est un organe spécialisé résultant du développement de l’ovaire après pollinisation et fertilisation, et qui offre un environnement adéquat pour la maturation des graines et leur dispersion. De part leur importance en nutrition humaine et leur importance économique, les espèces à fruit charnu ont été le sujet d’étude développementales principalement orientée vers la formation de l’ovaire, la mise à fruit et la maturation du fruit. La phase de croissance du fruit a été beaucoup moins étudiée, bien que la division cellulaire et la croissance cellulaire prenant place durant cette période soient cruciales à la détermination de la taille finale du fruit, ainsi que de sa masse et sa forme. Le développement du mésocarpe du fruit de tomate se déroule par la succession d’une phase de division cellulaire suivie d’une phase d’expansion cellulaire associée à l’endoréduplication, menant à la formation de cellules géantes (jusqu’à 0,5mm) avec des niveaux de ploïdie pouvant atteindre 256C. Bien qu’une relation évidente entre endoréduplication et croissance cellulaire ait été montrée par de nombreux exemples chez les plantes, le rôle exact de l’endoréduplication n’a toujours pas été élucidé, étant donné que la plupart des expériences induisant une modification du niveau d’endoréduplication dans la plante affectaient aussi la division cellulaire. Nous avons étudié la cinétique du dévelopement du mésocarpe de tomate au niveau morphologique et cytologique et avons étudié l’effet de la diminution du niveau d’endoréduplication sur le dévelopement du fruit en sur-exprimant l’inhibiteur du cycle cellulaire Kip-Related Protein 1 (SlKRP1) spécifiquement dans les cellules en croissance du mésocarpe de tomate. Nous montrons une proportionnalité directe entre endoréduplication et taille cellulaire durant le développement normal du fruit, ce qui nous a permis de construire un modèle de développement du mésocarpe définissant l’épaisseur du péricarpe en ne prenant en compte que le nombre de divisions cellulaires et le nombre de tours d’endoréduplication. De façon surprenante, les mésocarpes de tomate affectés dans leur niveau d’endoréduplication par la sur-expression de SlKRP1 ne sont pas affectés au niveau de la taille des cellules ou du fruit, ni dans leur contenu métabolique. Nos résultats démontrent pour la première fois qu’alors que le niveau de ploïdie est étroitement lié avec la taille des cellules et du fruit, l’endoréduplication n’est pas responsable de la croissance cellulaire du mésocarpe de tomateWithin the Joint Research Unit 619 of the National Institute of Agronomic Research (INRA), the group "Organogenesis of the Fruit and endoreduplication" examines the molecular players involved in cell cycle control in tomato fruit. The purpose of this thesis is the study of the cell cycle inhibitor Kip-Related Protein and its role during fruit development. Identification of protein motifs in the functional inhibitor of Cyclin-Dependent Kinase in Solanum lycopersicum SlKRP1: Their role in interactions with partners in the cell cycle The Kip-related proteins (KRPs) play a major role in the regulation of cell cycle. It has been shown to inhibit the CDK / Cyclin and thus block cell cycle progression. Despite their lack of homology with their counterparts in animals beyond their binding motif CDK / Cyclin, located at the C-terminal protein sequences in the plant, previous studies have shown the presence of conserved motifs plant specific in some KRPs, but there is little information about their function. We show here that the KRPs are distributed into two phylogenetic groups, and that each subgroup has specific short conserved motifs. The KRPs from subgroup 1 have six conserved motifs. Using SlKRP1, which belongs to subgroup 1, we have identified the motifs responsible for the localization of the protein and protein-protein interactions. We demonstrate that the pattern 2 is responsible for the interaction with CSN5, a subunit of the signalosome complex, and that the motif 5 is redundant with motif 3 with respect to the sub-cellular localization of the protein. We also show that SlKRP1 is capable of guiding SlCDKA1 and SlCycD3; 1 to the nucleus, even in the absence of CDK / cyclin binding motif previously referenced. This new site of interaction is probably located in the central part of the sequence of SlKRP1. These results provide new clues about the role of the little-known part of this protein. Overexpression of SlKRP1 in tomato mesocarp disrupts the proportionality between endoreduplication and cell size The fruit is a specialized organ which results from the ovary after pollination and fertilization, and provides a suitable environment for seed maturation and dispersal. Because of their importance in human nutrition and economic importance, fleshy fruit species have been the subject of study mainly focused on the developmental formation of the ovary, fruit set and fruit ripening. The stage of fruit growth has been much less studied, although cell division and cell growth taking place during this period are crucial to determining the final size of the fruit, as well as its mass and shape. The development of tomato fruit mesocarp occurs by the estate of a phase of cell division followed by a phase of cell expansion associated with endoreduplication, leading to the formation of giant cells (up to 0.5 mm) with ploidy levels of up to 256C. Although a clear relationship between endoreduplication and cell growth has been shown by many examples in plants, the exact role of endoreduplication has still not been elucidated, since most of the experiments leading to a change in the level of endoreduplication in plants also affected cell division. We studied the kinetics of the development of tomato mesocarp morphologically and cytologically and studied the effect of the reduced level of endoreduplication in the development of the fruit over-expressing the cell cycle inhibitor Kip-Related Protein 1 (SlKRP1) specifically in the growing cells of the tomato mesocarp. We show a direct proportionality between endoreduplication and cell size during normal development of the fruit, which allowed us to build a model for development of mesocarp defining the thickness of the pericarp by taking into account the number of cell divisions and the number of rounds of endoreduplication. Surprisingly, the tomato mesocarps affected in their level of endoreduplication by over-expression of SlKRP1 are not affected in terms of cell size and fruit, or on their metabolic content. Our results demonstrate for the first time that while the level of ploidy is closely linked with cell size and fruit, endoreduplication is not responsible for the cell growth of tomato mesocarp
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Handschick, Katja [Verfasser]. "Cyclin-dependent kinase (CDK) 6: ein molekularer Schalter zwischen dem Zellzyklus und der inflammatorischen Genregulation / Katja Handschick." Gießen : Universitätsbibliothek, 2014. http://d-nb.info/106858968X/34.
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Riley, Nicola Amy. "Cyclin-dependent kinase (CDK) inhibitor drugs induce apoptosis in human neutrophils through regulation of critical survival proteins." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/8171.
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Neutrophil apoptosis is an important process contributing to the resolution of inflammation. This is because it allows the neutrophil membrane to remain intact preventing it’s potentially histotoxic contents from being released into the extra-cellular milieu, a process that can contribute to the exacerbation of many inflammatory disorders such as rheumatoid arthritis. When considering the life-span of a neutrophil and how it can be augmented by various inflammatory mediators to allow it to carry out its essential protective role in the body’s innate immune defences it is also important to consider how to terminate this process when the inflammatory insult has been dealt with or when the system goes awry. It is this information that we believe may hold the key to developing novel anti-inflammatory therapies. Through exploitation of the mechanisms controlling neutrophil apoptosis, it may be possible to selectively target these cells to enter apoptosis, and therefore help aid the process of resolution, especially if used in conjunction with treatments that up-regulate phagocytosis of apoptotic cells. This is important given that the main treatment for disorders of the inflammatory response are glucocorticoids, which whilst proven to be a powerful treatment for eosinophil based diseases such as asthma where they increase eosinophil apoptosis in conjunction with enhancing phagocytic clearance of apoptotic cells, glucocorticoids have been found to have the converse affect on neutrophils, actually serving to prolong their life-span potentially exacerbating the condition. Furthermore, it has been previously shown that the transcription factor nuclear factor kappa B (NF-κB) plays a pivotal role in neutrophil apoptosis, becoming activated by inflammatory agents such as lipopolysaccharide (LPS) and tumour necrosis factor-alpha (TNF-α). NF-κB activation results in the transcription of many pro-inflammatory agents and anti-apoptotic proteins such as X-linked inhibitor of apoptosis (X-IAP) increasing the life-span of the neutrophil. Interestingly, it has also been demonstrated that key neutrophil survival proteins such as myeloid cell leukemia-1 (Mcl-1) are not directly regulated by NF-κB activation. Therefore it is because of the aforementioned reasons that I have chosen to investigate further neutrophil apoptosis including the role played by NF-κB. Thus, I have investigated the hypothesis that NF-κB-dependent and independent survival proteins critically regulate the rates of neutrophil apoptosis and that newly identified pro-apoptotic agents such as the cyclin-dependent kinase (CDK) inhibitor, R-roscovitine interferes with the expression of such survival proteins. It has been previously found by myself and others in our laboratory during the course of this thesis that cyclin dependent kinase inhibitor (CDKi) drugs such as R-roscovitine are powerful novel anti-inflammatory agents with the ability to up-regulate rates of neutrophil apoptosis in vitro and influence the resolution of neutrophilic inflammation in vivo. Whilst the exact mechanism of CDK inhibitor drugs on neutrophil apoptosis remains elusive, work shown in this thesis demonstrates that R-roscovitine has the ability to over-ride powerful anti-apoptotic signals from pro-inflammatory agents such as granulocyte-macrophage colony stimulating factor (GM-CSF) and LPS causing the neutrophils to enter apoptosis. Furthermore, it has been found that R-roscovitine causes a decrease in levels of the antiapoptotic protein Mcl-1 in as little as 2h and that it prevents the maintenance / protective effect that GM-CSF has on the Mcl-1 protein levels. In addition R-roscovitine may also reduce levels of the NF-κB regulated protein X-IAP. The effect of R-roscovitine on X-IAP was investigated further using an X-IAP HIV-tat construct, though results from this remain inconclusive. This is because although the X-IAP construct appeared to be extending neutrophil longevity, it was discovered that LPS contamination of the construct had occurred which could therefore pose an alternative explanation for the increase in neutrophil life-span. As X-IAP, TNF-α and LPS are all regulated by NF-κB and given that NF-κB is already known to be a key player in neutrophil biology, the effects of R-roscovitine on this important transcription factor were investigated. It was discovered that R-roscovitine does not directly activate NF-κB, since this CDK inhibitor drug does not cause degradation and loss of the cytoplasmic inhibitor of NF-κB, IκBα. This lack of NF-κB activation was confirmed since R-roscovitine did not mobilize the NF-κB subunit, p65, from the cytoplasm to the nucleus. Furthermore, R-roscovitine (unlike the NF-κB inhibitor gliotoxin) does not interfere with the ability of LPS or TNF-α to activate NF-κB. Therefore by R-roscovitine to induce apoptosis, although this does not rule out the involvement of NF-κB at a later stage. When considering a reagent for possible use as a novel anti-inflammatory agent I think it is important to assess what effects it has on the activation state of the neutrophil. Therefore the effects of R-roscovitine on the activation markers CD62L, CD11b and shape change were assessed. It was found that R-roscovitine alone did not cause any significant neutrophil activation as measured using the parameters stated above. Importantly, it was also found that R-roscovitine did not interfere with the activation states induced by the inflammatory mediators GM-CSF, LPS, TNF-α or leukotriene B4 (LTB4). Another important consideration is the effect of R-roscovitine on the removal of apoptotic cells by macrophage phagocytosis. Results demonstrated that pre-treatment of macrophages with R-roscovitine did not augment their uptake of apoptotic neutrophils. In addition Rroscovitine did not detrimentally affect the increase in phagocytosis that results from macrophage treatment with the synthetic glucocorticoid dexamethasone. The data presented in this thesis suggest that CDK inhibitor drugs such as R-roscovitine are novel powerful pro-apoptotic agents for neutrophils with the ability to over-ride antiapoptotic signals from multiple pro-inflammatory mediators. It has been discovered that Rroscovitine causes a reduction in one of the neutrophil’s most prominent anti-apoptotic proteins (Mcl-1) whilst not altering the activation state of the neutrophil and furthermore it does not interfere with the uptake of apoptotic neutrophils by macrophages or result in any alteration to the increase in phagocytosis caused by treatment with dexamethasone. In conclusion, CDK inhibitor drugs such as R-roscovitine have the potential to be promising candidates for novel anti-inflammatory agents with the ability to selectively target neutrophil apoptosis whilst not interfering with steroid induced up-regulation of phagocytosis, therefore allowing a two pronged attack to help treat neutrophil based inflammatory disorders.
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Weitensteiner, Sabine. "Cyclin-dependent kinase 5 in endothelial cell migration: Elucidating regulatory mechanisms upstream of Cdk5 and evaluating novel Cdk inhibitors as anti-angiogenic drugs." Diss., lmu, 2011. http://nbn-resolving.de/urn:nbn:de:bvb:19-136480.
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Gloulou, Olfa. "Identification de nouvelles structures inhibitrices de kinases : conception synthèse et évaluation biologique." Thesis, Paris 5, 2013. http://www.theses.fr/2013PA05P637/document.
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Cette thèse a pour objectif l’identification de nouveaux inhibiteurs de kinase et plus particulièrement de kinases dépendantes de cyclines (CDKs). Des inhibiteurs de CDKs sont en essais cliniques depuis une dizaine d’année. Un faisceau d’informations récentes montre que cette nouvelle classe pharmacologique pourrait prochainement occuper une place prépondérante dans la thérapie antitumorale. L’introduction de cette thèse décrit les principaux inhibiteurs de CDKs en se focalisant sur ceux dont le développement clinique est en cours et sur les structures les plus récemment divulguées (2009 à 2013). Trois molécules avancées en études cliniques s’avèrent intéressantes et s’approchent de la mise sur le marché : la Roscovitine (phase clinique IIb), le Dinaciclib (phase clinique III) et le Palbociclib (phase clinique III). D’un point de vue expérimental, cette thèse se décompose en deux parties principales. La première modulation a consisté à rechercher des nouveaux groupements qui pourraient sur des squelettes déjà connus comme les purines apporter un avantage en ce qui concerne l’activité des produits. Les structures cristallines des complexes inhibiteur-enzymes et notamment celles de Roscovitine-CDK2 et CR8-CDK2 ont guidé la conception des nouvelles molécules. C’est ainsi que sur les structures biaryliques déjà connues, un groupement phénol a été greffé sur l’un des cycles conduisant ainsi à de nouveaux inhibiteurs de kinases. Ces molécules sont plus puissantes que les produits non hydroxylés. L’augmentation de l’activité est particulièrement sensible au niveau de la kinase CDK2 qui est impliquée notamment dans régulation du cycle cellulaire. La seconde partie du travail porte sur la recherche de structures isostères des purines. Ainsi, le squelette thieno[3,2-d]pyrimidines a été développé de novo. Deux types d’intermédiaires produits ont été préparés afin de permettre la diversification des structures. En premier temps la voie de synthèse via l’intermédiaire thiométhyle a été conduite, néanmois cette voie présente certaines limites. Le deuxième intermédiaire trihalogéné a permi d’optimiser la préparation des molécules thieno[3,2-d]pyrimidines. Les évaluations des produits préparés ne sont pas totalement terminées. Ces molécules sont moins puissantes que les purines sur les CDKs mais agissent au niveau d’autres kinasesIn the introduction, the main functions of cyclin dependent kinases are detailed. Whenever it was possible the link with pathologies where these kinases are overexpressed is presented. This is followed by the description of the inhibitors which are actually undergoing clinical testing. Most of these clinical studies are targeting cancer and leukemia. Impressive clinical results have been disclosed for Dinaciclib, Palbociclib and Roscovitine. The synthesis of two series of compounds is then envisioned. The first series of products are purine derivatives bearing a hydroxybiarylmethyl group on the 6 position of the purine scaffold. Two approaches were compared in the synthesis of the hydroxylbiarylmethylamino group. In both approaches the key step was the orthoformylation of phenols using magnesium chloride as catalyst. The prepared compounds were evaluated against kinases and a tumor cell line. They were found more potent than homologous products without hydroxyls. The second families of products are thieno[3,2-d]pyrimidines. A new general route to these products based on the preparation of 7-bromo-2,4-dichloro-thieno[3,2-d]pyrimidine which can allow the synthesis of a large diversity of trisubstituted derivatives
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Johnson, Neil. "Investigation into the therapeutic potential of novel cyclin dependent kinase (CDK) inhibitors in the treatment of antiestrogen sensitive and resistant breast cancer." Thesis, University of Newcastle Upon Tyne, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427304.
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Weitensteiner, Sabine [Verfasser], and Stefan [Akademischer Betreuer] Zahler. "Cyclin-dependent kinase 5 in endothelial cell migration : elucidating regulatory mechanisms upstream of Cdk5 and evaluating novel Cdk inhibitors as anti-angiogenic drugs / Sabine Weitensteiner. Betreuer: Stefan Zahler." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2011. http://d-nb.info/1017233233/34.
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Bisteau, Xavier. "Activation de la CDK4, clef de l'engagement du cycle cellulaire et carrefour des voies oncogéniques: évaluation de l'implication de la kinase activatrice des CDKs (CAK) et des phosphorylations de p21." Doctoral thesis, Universite Libre de Bruxelles, 2013. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209523.
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Ganier, Olivier. "Etude des fonctions de la cycline A2 dans la progression du cycle cellulaire des cellules de mammifères." Paris 6, 2007. http://www.theses.fr/2007PA066207.
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Le déroulement ordonné des phases G1, S, G2 et M du cycle cellulaire est principalement contrôlé par l'activité des kinases dépendantes des cyclines (CDK). La cycline A2 est présente dès la transition G1/S jusqu'en prométaphase. Afin de déterminer ses fonctions spécifiques dans la progression du cycle cellulaire des cellules de mammifères, nous avons inhibé son expression par interférence à l'ARN. Ceci conduit à une accélération de l'entrée en phase S suivante. Sa ré-expression restreinte au cycle cellulaire précédent est suffisante pour rétablir un "timing" correct d'entrée en phase S. L'inhibition de l'expression de la cycline A2 conduit à une stabilisation anormale de ORC1 sur la chromatine dès la mitose précédente et durant la phase G1 suivante et son expression ectopique conduit également à une accélération de l'entrée en phase S, suggérant que la phase S est régulé lors du cycle cellulaire précédent et que l'action de la cycline A2 sur ORC1 participe à cette régulation.
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Lindqvist, Arne. "Regulation of CDK dephosphorylation in mitotic entry /." Stockholm, 2005. http://diss.kib.ki.se/2005/91-7140-362-0/.
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Bajaj, Narinder Singh. "Cyclin dependent kinase 5 (CDK5) and neurodegeneration." Thesis, King's College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312768.
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Brümmer, Anneke. "Mathematical modelling of DNA replication." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2010. http://dx.doi.org/10.18452/16212.
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Bevor sich eine Zelle teilt muss sie ihr gesamtes genetisches Material verdoppeln. Eukaryotische Genome werden von einer Vielzahl von Replikationsstartpunkten, den sogenannten Origins, aus repliziert, die über das gesamte Genome verteilt sind. In dieser Arbeit wird der zugrundeliegende molekulare Mechanismus quantitativ analysiert, der für die nahezu simultane Initiierung der Origins exakt ein Mal pro Zellzyklus verantwortlich ist. Basierend auf umfangreichen experimentellen Studien, wird zunächst ein molekulares regulatorisches Netzwerk rekonstruiert, welches das Binden von Molekülen an die Origins beschreibt, an denen sich schließlich komplette Replikationskomplexe (RKs) bilden. Die molekularen Reaktionen werden dann in ein Differentialgleichungssystem übersetzt. Um dieses mathematische Modell zu parametrisieren, werden gemessene Proteinkonzentrationen als Anfangswerte verwendet, während kinetische Parametersätze in einen Optimierungsverfahren erzeugt werden, in welchem die Dauer, in der sich eine Mindestanzahl von RKs gebildet hat, minimiert wird. Das Modell identifiziert einen Konflikt zwischen einer schnellen Initiierung der Origins und einer effizienten Verhinderung der DNA Rereplikation. Modellanalysen deuten darauf hin, dass eine zeitlich verzögerte Origininitiierung verursacht durch die multiple Phosphorylierung der Proteine Sic1 und Sld2 durch Cyclin-abhängige Kinasen, G1-Cdk bzw. S-Cdk, essentiell für die Lösung dieses Konfliktes ist. Insbesondere verschafft die Mehrfach-Phosphorylierung von Sld2 durch S-Cdk eine zeitliche Verzögerung, die robust gegenüber Veränderungen in der S-Cdk Aktivierungskinetik ist und außerdem eine nahezu simultane Aktivierung der Origins ermöglicht. Die berechnete Verteilung der Fertigstellungszeiten der RKs, oder die Verteilung der Originaktivierungszeiten, wird auch genutzt, um die Konsequenzen bestimmter Mutationen im Assemblierungsprozess auf das Kopieren des genetischen Materials in der S Phase des Zellzyklus zu simulieren.Before a cell divides it has to duplicate its entire genetic material. Eukaryotic genomes are replicated from multiple replication origins across the genome. This work is focused on the quantitative analysis of the underlying molecular mechanism that allows these origins to initiate DNA replication almost simultaneously and exactly once per cell cycle. Based on a vast amount of experimental findings, a molecular regulatory network is constructed that describes the assembly of the molecules at the replication origins that finally form complete replication complexes. Using mass–action kinetics, the molecular reactions are translated into a system of differential equations. To parameterize the mathematical model, the initial protein concentrations are taken from experimental data, while kinetic parameter sets are determined using an optimization approach, in particular a minimization of the duration, in which a minimum number of replication complexes has formed. The model identifies a conflict between the rapid initiation of replication origins and the efficient inhibition of DNA rereplication. Analyses of the model suggest that a time delay before the initiation of DNA replication provided by the multiple phosphorylations of the proteins Sic1 and Sld2 by cyclin-dependent kinases in G1 and S phase, G1-Cdk and S-Cdk, respectively, may be essential to solve this conflict. In particular, multisite phosphorylation of Sld2 by S-Cdk creates a time delay that is robust to changes in the S-Cdk activation kinetics and additionally allows the near-simultaneous activation of multiple replication origins. The calculated distribution of the assembly times of replication complexes, that is also the distribution of origin activation times, is then used to simulate the consequences of certain mutations in the assembly process on the copying of the genetic material in S phase of the cell cycle.
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Jämsä, Anne. "In vitro modelling of tau phosphorylating kinases: emphasis on Cdk5 /." Stockholm, 2007. http://diss.kib.ki.se/2007/978-91-7357-400-6/.
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Zeng, Fanli. "Novel Modes of Regulation of Cyclin Dependent Kinase Cdk1." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/133357.
Full textAbstract:
Les quinases dependents de ciclina (CDKs) dirigeixen la progressió del cicle cel·lular a
les cèl·lules eucariotes. A l’organisme eucariota model Saccharomyces cerevisiae
(llevat de gemmació) una sola quinasa dependent de ciclina, Cdk1, és essencial i
suficient per dirigir el cicle cel·lular. Unida alternativament a ciclines de fase G1, S i
G2/M, Cdk1 regula els programes transcripcionals del cicle cel·lular, la replicació i
segregació dels cromosomes, la dinàmica del fus mitòtic, el creixement cel·lular polar,
la morfogènesi, etc. La desregulació de l’activitat CDK promou la proliferació
descontrolada i la inestabilitat genòmica.
Donada la seva funció essencial en la progressió del cicle cel·lular, Cdk1 és
estretament regulada per proteïnes associades (les ciclines, Cks1, i inhibidors de les
CDKs –CKIs) i per modificacions post-traduccionals. Tanmateix, molts detalls de la
regulació de Cdk1 romanen desconeguts, com és el cas de com les activitats CDK de
fase G1 o de fase M són inhibides en resposta a determinats estressos cel·lulars.
Quan la progressió del cicle cel·lular és amenaçada per la presència d’estressos
genotòxics tals com l’estrès replicatiu o la presència de dany al DNA, un mecanisme de
vigilància, l’anomenat checkpoint de la fase S, s’activa per tal de protegir la integritat
del genoma. Al llevat de gemmació, el checkpoint de la fase S és mediat per la quinasa
Mec1 (ATR/ATM a humans) i la seva quinasa efectora Rad53 (Chk2 a humans).
Per explorar si la quinasa efectora Rad53 regula Cdk1 en resposta a estrès
genotòxic, hem explorat dues qüestions principals: (1) la fosforilació de Cdk1 per
Rad53 i (2) la regulació per Rad53 de proteïnes associades a Cdk1.
Pel que fa a la primera qüestió, aprofitant un assaig quinasa in vitro amb Rad53,
mostrem que Cdk1 és fosforilat directament per Rad53. Hem identificat
proteòmicament dos llocs de Cdk1 (Ser46, Ser258) fosforilats per Rad53 in vitro. Les
cèl·lules dirigides per l’al·lel no-fosforilable (Cdk1-2A) mostren un fenotip wee,
compatible amb una activitat CDK incrementada/desregulada. Les cèl·lules dirigides
per l’al·lel fosfomimètic (Cdk1-2E) són allargades i més grans que les cèl·lules
silvestres, compatible amb una activitat CDK reduïda. A més, assignem i quantifiquem
les diferents formes fosforilades de Cdk1 in vivo mitjançant electroforesi Phos-tag.
Respecte la segona qüestió, hem identificat proteòmicament proteïnes associades
a Cdk1 en presència d’estrès replicatiu en forma dependent de Rad53. Hem estudiat en
detall el producte del gen de funció desconeguda YPL014W, que bategem Cip1 (per
Cdk1 Interacting Protein 1), que obté la puntuació més alta en l’anàlisi. Les nostres
dades mostren que Cip1 és una proteïna regulada al llarg del cicle cel·lular. A més,
l’abundància de Cip1 s’incrementa en forma dependent de Rad53 en presència d’estrès
replicatiu. La sobre-expressió de Cip1 bloqueja les cèl·lules a fase G1 i estabilitza el
CKI de fase S Sic1 in vivo. A més, Cip1 interacciona específicament amb el complex de
fase G1 Cln2-Cdk1, però no amb el complex de fase S Clb5-Cdk1 or el de fase M
Clb2-Cdk1. Cip1 inhibeix l’activitat Cln2-CDK tant in vivo com in vitro. Els nostres
resultats suggereixen que Cip1 pot ser un nou CKI de l’activitat CDK de fase G1.Cyclin dependent kinases are drive cell division cycle progression in eukaryotic cells. In the model eukaryotic organism Saccharomyces cerevisiae (budding yeast) a single Cyclin Dependent Kinase, Cdk1, is essential and sufficient to drive the cell cycle. Alternately bound to G1, S and G2/M phase cyclins, Cdk1 regulates cell cycle transcriptional programs, chromosome replication and segregation, spindle dynamics, polarized cell growth, morphogenesis, etc. Misregulated CDK activity induces unscheduled proliferation as well as genomic instability. Given its essential function in cell cycle progression, Cdk1 is tightly regulated by binding partners (cyclins, Cks1 and Cyclin dependent Kinase Inhibitors -CKIs) and post-translational modifications. However, many details on Cdk1 regulation remain unknown, such as how G1 or mitotic CDK activities are inhibited in response to challenging conditions. When the cell cycle progression is challenged by genotoxic stress such as DNA replication stress or DNA damage, a surveillance mechanism, the S phase checkpoint is activated to protect the integrity of the genome. In the budding yeast the S phase checkpoint is mediated by the Mec1 kinase (ATR/ATM in humans) and its downstream effector kinase Rad53 (Chk2 in humans). To explore whether the effector kinase Rad53 regulates Cdk1 in response to genotoxic stress, we have been exploring two main avenues: (1) Cdk1 phosphorylation by the S phase checkpoint effector kinase Rad53 and (2) Rad53 dependent regulation of Cdk1 associated factors. With respect to the first question, taking advantage of a Rad53 in vitro kinase assay, we show that recombinant Cdk1 is directly phosphorylated by Rad53. We also proteomically identified two sites of Cdk1 (Ser46, Ser258) phosphorylated by Rad53 in vitro. Cells carrying the non-phosphorylatable Cdk1 allele (Cdk1-2A) display a wee phenotype, compatible with increased/unrestrained CDK activity. Cells carrying the phosphomimetic Cdk1 allele (Cdk1-2E) are elongated and larger in size than wild type cells. Moreover, we also assign and quantify the different phosphorylation forms of Cdk1 in vivo using Phos-tag electrophoresis technology. With respect to the second question, we have proteomically identified proteins associated with Cdk1 in the presence of replication stress in a Rad53 dependent manner. The product of the unknown function gene YPL014W, which we name Cip1 (for Cdk1 Interacting Protein 1), with the highest score, is further studied. Our data shows that Cip1 is a cell cycle regulated protein. In addition, the abundance of Cip1 increases in a Rad53 dependent manner upon DNA replication stress. Overexpression of Cip1 blocks cells in G1 and stabilizes the S-phase-Cdk1 inhibitor Sic1 in vivo. Moreover, Cip1 specifically interacts with G1 phase Cln2-Cdk1 but not with S phase Clb5-Cdk1 or M phase Clb2-Cdk1. Cip1 inhibits Cln2-CDK activity both in vivo and in vitro. Our finding suggests that Cip1 may be a novel CKI of G1 phase CDK activity.
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Harlow, Lisa Katherine. "Structure-activity studies of 2-arylaminopurine cyclin-dependant kindase (CDK) inhibitors." Thesis, University of Newcastle Upon Tyne, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.505843.
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Cheng, Kai. "Identification of Pctaire1 as a p35-interacting protein and a novel substrate for Cdk5 /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?BICH%202003%20CHENG.
Full textAbstract:
Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2003.Includes bibliographical references (leaves 153-177). Also available in electronic version. Access restricted to campus users.
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Henderson, Andrew. "Isosteres of sulfonamide inhibitors of cyclin-dependent kinases (CDKs)." Thesis, University of Newcastle Upon Tyne, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.512187.
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Chen, Jian 1969. "Regulation of CAK activity of Cdk7 in Drosophila melanogaster." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82842.
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Cdk7 (Cyclin-dependent kinase 7) is conserved from yeast to human and involved in multiple functions. Cdk7 acts as a CAK (Cdk activating kinase) in a trimeric complex with Cyclin H and Mat1. The CAK activity is required for the full activation of the Cdks that directly regulate the cell cycle transitions. In addition, Cdk7 is the kinase subunit of TFIIH, the general transcription/DNA repair factor IIH. TFIIH is required for the general transcription of messenger RNAs by RNA polymerase II and for the transcription-coupled nucleotide excision repair functions. As in other systems, Drosophila Cdk7 has multiple functions. In order to understand how different functions of Cdk7 are regulated, I performed genetic screens to identify the regulators or downstream factors of multiple functions of Cdk7. Several candidate dominant suppressors and enhancers were identified in these screens. One strong suppressor of cdk7, xpd, encodes another subunit of TFIIH. The genetic suppression by xpd attracted me to further characterize the biological significance of this interaction. I showed that Xpd does have a novel function in regulating CAK activity of cdk7 , it down-regulates mitotic CAK activity. Furthermore, I found that Xpd protein levels are cell cycle dependent, being down-regulated at the beginning of the mitosis. Based on these data, I propose a model that mitotic down-regulation of Xpd results in increased CAK activity, positively regulating mitotic progression. Simultaneously, this down-regulation can be expected to contribute to the mechanisms of mitotic silencing of basal transcription.
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He, Lisheng. "Characterization of p35, a neuronal activator of Cdk5, as a novel microtubule-associated protein /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?BICH%202007%20HE.
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Ren, Ping. "Control of cytokinesis by the mitotic cyclin dependent kinase M-Cdk1." Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/458616.
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La citocinesi és el darrer procés regulat del cicle de divisió cel·lular mitòtica eucariota.
Les cèl·lules entren en citocinesi un cop la segregació dels cromosomes s’ha
completat satisfactòriament. Durant la citocinesi les cèl·lules es separen físicament,
donant lloc a dues cèl·lules filles. Els defectes en el control de la citocinesi donen lloc
a aneuploïdies i inestabilitat genòmica. Un controlador clau de la citocinesi és
l’activitat Quinasa Dependent de Ciclina (M-Cdk1). El nostre projecte deriva de la
correlació observada entre l’entrada en citocinesi i l’eliminació de l’activitat M-Cdk1.
Complementària a aquesta observació, l’expressió d’un al·lel hiper-estable de la
ciclina mitòtica Clb2 bloca la citocinesi. Per tant, la mateixa activitat que empeny les
cèl·lules a entrar en mitosi i que hi promou l’anafase, impedeix que la citocinesi pugui
iniciar-se prematurament. Aquestes observacions suggereixen que una o més
proteïnes, essencials per disparar la citocinesi, són inhibides per fosforilació per MCdk1.
La identitat d’aquest/s substrat/s crític/s és desconeguda. Per tant, l’objectiu
d’aquesta tesi ha estat el d’avançar en la comprensió de com l’activitat M-Cdk1 evita
la citocinesi prematura durant l’anafase, a l’organisme eucariota model
Saccharomyces cerevisiae. El treball realitzat revela que, en presència dominant
d’activitat M-Cdk1 elevada, la Xarxa de Sortida de Mitosi (Mitotic Exit Network,
MEN) està, contra tot pronòstic, parcialment activada en presència d’activitat M-Cdk1
elevada i dominant, i és la responsable de l’alliberament de la fosfatasa Cdc14 al
citoplasma en aquestes condicions.Cytokinesis is the final regulated process in the eukaryotic mitotic cell division cycle. Cells enter cytokinesis once that chromosome segregation is satisfactorily completed. During cytokinesis cells physically separate, giving place to two daughter cells. Defects in the control of cytokinesis result in aneuploidies and genomic instability. A key controller of cytokinesis is the mitotic Cdk1 (M-Cdk1) activity. Our project derives from the observed correlation between the onset of cytokinesis and the termination of M-Cdk1 activity. Complementary to such observation, expression of a hyperstable allele of the mitotic cyclin Clb2, blocks cytokinesis. Thus, the very same activity that pushes cells into mitosis and promotes mitotic entry and anaphase, blocks the occurrence of premature cytokinesis. These observations suggest that one or more proteins, essential to trigger cytokinesis, are inhibited by M-Cdk1 phosphorylation. The identity of such critical M-Cdk1 substrate/s is unknown. Therefore, the goal of this thesis is to gain insight on how M-Cdk1 prevents premature cytokinesis during anaphase in the model eukaryotic organism Saccharomyces cerevisiae. The thesis work reveals that the Mitotic Exit Network is unexpectedly partially activated in the presence of prevailing high M-Cdk1 activity, and drives the release of the Cdc14 phosphatase to the cytoplasm under such conditions.
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Wu, Qian. "Involvement of Cdk5/p35 in EphB2-dependent dendritic spine development /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?BICH%202008%20WUQ.
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Ng, Kung Yau. "ANKRA2 interacts with p35 and is a substrate for Cdk5/p35 /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?BICH%202006%20NG.
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Chin, Wing Hong. "Identification of TrkB as a p35 interacting protein and a Cdk5 substrate /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?BICH%202005%20CHIN.
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Poh, Wei Theng. "The role of Cdc7 and cyclin-dependent kinases in DNA replication and S phase." Thesis, University of Dundee, 2012. https://discovery.dundee.ac.uk/en/studentTheses/a5399a6d-9aef-4152-9a13-222dcf27aa55.
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The cell cycle is a highly orchestrated developmental process that eventually leads to the reproduction of a cell. In metazoans, it is driven by the successive activation of cyclin-dependent kinases (Cdk) and proper coordination of cell cycle transitions and processes ensure genomic stability. DNA replication takes place during S phase to faithfully duplicate a cell’s genetic material. In eukaryotes, S phase onset involves the initiation of numerous licensed replication origins across the genome and requires the activities of two protein kinases, S phase-Cdk and Cdc7. In this thesis, I present work relating to the role of the S phase-promoting kinases in DNA replication and S phase regulation. Using the cell-free system of Xenopus egg extracts, a small molecule inhibitor of Cdc7, PHA-767491, was characterised. PHA-767491 was then used to demonstrate that Cdc7 executes its activity early in S phase before the Cdk-dependent step. Cdc7 is not rate limiting for the progression of the replication timing programme once its essential function has been executed, unlike S-Cdk whose activity is required throughout S phase. Protein Phosphatase 1 (PP1) was identified as a modulator of Cdc7 activity in egg extracts, which rapidly reverses Cdc7-dependent phosphorylation of chromatin-bound Mcm4 and likely functionally lowers Cdc7 activity during an etoposide-induced checkpoint response. This provides a novel mechanism for regulating Cdc7 by counteracting its activity on essential replication substrates in the event of replicative stress. In the second part of the thesis, the design strategy for generating a Cdc7-conditional knockout mouse (cko) is outlined and results from the screen for a transgenic founder are presented. A Cdc7-cko mouse will be a valuable tool to further dissect Cdc7 function and regulation in mammalian cells. In the final section, S phase entry and progression in mouse embryonic fibroblasts lacking both Cdk1 and Cdk2 was examined. Contrary to expectations, Cdk1/Cdk2 double knockout cells can enter S phase in the absence of detectable S phase-Cdk activity. S phase progression, however, was inefficient. Cdc6 and cyclin E1 proteins were found to accumulate in high levels in these cells. The exact function(s) and mechanism(s) for these observations remain to be discovered. With this work, I hope to provide additional insight into the roles and regulation of S phase kinases in eukaryotic DNA replication.
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Yu, Yan. "Functional investigation of the neuronal Cdk5 activator p35 in the regulation of actin dynamics /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?BICH%202005%20YUY.
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Hou, Zhibo. "Function and regulation of the neuronal Cdk5/p35 kinase in the control of protein translation /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?BICH%202007%20HOU.
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Soni, Deena. "Studies on regulation of mitotic transition by cyclin B1/CDK1." Connect to text online, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=case1099070698.
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Thesis (Ph. D.)--Case Western Reserve University, 2005.[School of Medicine] Department of Environmental Health Sciences. Includes bibliographical references. Available online via OhioLINK's ETD Center.
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Xu, Pei. "Cdk5 activity is required for BDNF-stimulated neuronal survival and synaptic plasticity /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?BICH%202008%20XU.
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Dixon-Clarke, Sarah. "Structure and inhibition of novel cyclin-dependent kinases." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:3c6955c9-469a-4f4b-9577-309ccb57b742.
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Protein phosphorylation by members of the cyclin-dependent kinase (CDK) family determines the cell cycle and regulates gene transcription. CDK12 and CDK16 are relatively poorly characterised family members containing atypical domain extensions and represent novel targets for structural studies, as well as cancer drug discovery. In this thesis, I developed protocols to express and purify the human CDK12 kinase domain in complex with its obligate partner, CycK. I solved three distinct crystal structures of the complex providing insights into the structural mechanisms determining CycK assembly and kinase activation. These structures revealed a C-terminal kinase extension that folded flexibly across the active site of CDK12 to potentially gate the binding of the substrate ATP. My structures also identified Cys1039 in the C-terminal extension as the binding site for the first selective covalent inhibitor of CDK12, which has enormous potential as a pharmacological probe to investigate the functions of CDK12 in the DNA damage response and cancer. I also identified rebastinib and dabrafenib as potent, clinically-relevant inhibitors of CDK16 and solved a co-crystal structure that defined the extended type II binding mode of rebastinib. Preliminary trials using these relatively non-selective compounds to inhibit CDK16 in melanoma and medulloblastoma cancer cell lines revealed rebastinib as the more efficacious drug causing loss of cell proliferation in the 1-2 micromolar range. Use of the co-crystal structure to design more selective derivatives would be advantageous to further explore the specific role of CDK16. Finally, I identified a D-type viral cyclin from Kaposi's sarcoma-associated herpesvirus that could bind to the CDK16 kinase domain and interfere with its functional complex with human CycY causing loss of CDK16 activity. These studies provide novel insights into the structural and regulatory mechanisms of two underexplored CDK family subgroups and establish new opportunities for cancer drug development.
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Auckland, Ian. "Quantitative Analysis of a Cell Cycle Checkpoint in Xenopus laevis Cell-Free Egg Extracts." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/34734.
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In somatic cells, checkpoint pathways trigger cell cycle arrest in response to
unreplicated or damaged DNA by inhibiting the activity of cyclin-dependent kinases
(Cdks). In the Xenopus laevis embryo, checkpoints are not operational until the
midblastula transition (MBT). Studies in cell-free egg extracts indicate that a threshold
concentration of nuclei, which approximates the MBT concentration, is required to elicit
a checkpoint. The checkpoint response to unreplicated DNA in the extract prevents
transition into mitosis by inhibiting Cdk1/cyclin B, causing an increase in the minimum
amount of cyclin B necessary to enter mitosis, termed the cyclin threshold. Once the
threshold of cyclin is maintained or exceeded, the system will proceed into mitosis after a
lag time. We have investigated the relationship between nuclear concentration and cell
cycle regulation in the extract. By precisely regulating the concentration of cyclin B and
nuclear content in extract samples, we have found 1) the concentration of nuclei affects
cyclin B thresholds and lag time of entry into mitosis, 2) elevated cyclin thresholds
caused by DNA replication blocks are further increased by increasing the concentration
of nuclei, and 3) double-stranded DNA breaks in the extract system do not affect cyclin
thresholds or lag time of entry into mitosis within the range of nuclear concentrations that
can be efficiently replicated. This data provides evidence of the importance of the
nucleocytoplasmic ratio in normal cell cycle progression and its importance for
checkpoint acquisition during early Xenopus laevis development.Master of Science
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Romsaiyud, Jariya. "Synthesis of the small peptide analogues of cyclin dependent kinase (CDK4) for cancer treatment." Thesis, University of Southampton, 2010. https://eprints.soton.ac.uk/191335/.
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Cyclin-dependent kinases (CDKs) are a group of enzymes that are involved in cell cycle progression regulation. The CDKs activate host proteins through phosphorylation on serine or threonine using adenosine triphosphate as a phosphate donor. Especially, cyclindependent kinase 4 (CDK4) has attracted much attention as a potential therapeutic target in treating cancer because it is the key player in the control of cell proliferation. Comparison of the best model of CDK4 with the structures of CDK6 and CDK2 is shown difference in the cyclin-binding region and in overall electrostatic potential. A partially hydrophobic, externalized loop structure present in CDK4, but absent in CDK2 and CDK6 is identified. The hypothesis is that should CDK4 be involved in binding to an additional unidentified protein partner, this fragment provides the most likely candidate for the binding site. This has led to the discovery of a peptide 1, N-Ac-L-Pro-L-Arg(H)-Gly-L-Pro-L-Arg(H)-L-Pro- NH2, from a previously uncharacterized structural domain on CDK4. In this work, solution phase peptide synthetic method is optimized and developed to synthesize linear peptide 64, N-Boc-L-Pro-L-Arg(NO2)-Gly-L-Pro-L-Arg(NO2)-L-Pro-OMe. A series of side chain modification peptides of compound 64 was synthesized and found that peptide 71, N-Ac-LPro- L-Arg(NO2)-Gly-L-Pro-L-Arg(NO2)-L-Pro-OMe had the most potent for anticancer activity. Therefore, alanine scanning compounds of hexapeptide 71 were synthesized by replacing each amino acid residue with L-alanine to investigate which amino acid residue had shown anticancer activity. Solid phase method was also optimized to synthesized peptide 1 and its alanine scanning compounds. To improve anticancer activity, cyclic peptides are synthesized by solution phase method. Biological assays were optimized. Clonogenic assay was chosen to test with our synthetic peptides against RT112 bladder cancer and MRC5-hTERT fibroblast cells
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Soni, Deena V. "Studies on the regulation of mitotic transition by cyclin B1/Cdk1." Case Western Reserve University School of Graduate Studies / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=case1099070698.
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Stott, Francesca Joanne. "Analysis of the INK4 family of cyclin dependent kinase inhibitors, in the mammalian cell cycle." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322001.
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Ji, Jun-Yuan. "Functions of Cdk1-cyclin B in regulating the early embryonic mitoses in Drosophila /." Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/5124.
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Santos, André Bandiera de Oliveira. "Expressão imuno-histoquímica das proteínas p16, ciclina D1, CDK4, pRb, p53 e p21 em melanomas cutâneos de cabeça, pescoço e tronco e sua relação com prognóstico." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/5/5132/tde-21062010-171113/.
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O melanoma cutâneo é a neoplasia de pele de maior mortalidade. A imprevisibilidade de sua evolução é uma de suas características principais, o tratamento do tumor primário é, atualmente, de pouca morbidade e, na doença disseminada, as opções terapêuticas são pouco eficazes. É fundamental a pesquisa de marcadores tumorais que permitam a previsão da evolução, melhor compreensão da patogênese do melanoma e possibilitem a descoberta de alvos moleculares. Nesse contexto, estudos genéticos mostraram a importância da regulação do ciclo celular, especialmente a passagem da fase G1-S. Importantes fatores envolvidos compõem a cascata da proteína Rb (p16, ciclina D1, CDK4 e pRb) e da proteína p53 (p53 e p21). Objetivo: verificar a frequência da expressão de p16, ciclina D1,CDK4, pRb, p53 e p21 em melanomas cutâneos de cabeça, pescoço e tronco e sua relação com prognóstico. Métodos: Estudo retrospectivo envolvendo 46 pacientes (sendo 67,3% homens, idade média 57,7 ± 15,8 anos) com melanoma cutâneo de cabeça, pescoço e tronco que foram tratados pela mesma equipe com seguimento mínimo de dois anos. Foram estudados fatores clínicos (topografia do tumor primário, tempo de seguimento, ocorrência de metástases e óbito relacionado), histopatológicos (tipo histológico, índice de Clark, índice de Breslow) e análise imuno-histoquímica pela técnica de micro-array para as proteínas reguladoras do ciclo celular p16, ciclina D1, CDK4, pRb, p53 e p21. Resultados: Houve proporção igualitária entre as topografias (23 casos em tronco, 23 em cabeça e pescoço). Treze pacientes com Clark I (29,5%), cinco com II (11,3%), 16 com III (36,5%), 10 com IV (22,7%) e nenhum com Clark V. A média das medidas de Breslow foi 0,96 (DP=1,01). O seguimento médio foi de 77 meses (DP=47). Oito dos 46 pacientes (17,3%) tiveram evolução desfavorável, com seis óbitos relacionados. A idade foi mais elevada no grupo com evolução desfavorável (p=0,04). Houve expressão de p16 em 80%, ciclina D1 em 58,9%, CDK4 em 43,5%, pRb em 58,5%, p53 em 53,6% e p21 em 52,3% dos melanomas. Em análise univariada, a expressão do p21 foi relacionada com evolução desfavorável (p=0,04), o que não foi observado com a expressão dos outros marcadores (p>0,05). Conclusão: A expressão da proteína p21 nos melanomas cutâneos de cabeça, pescoço e tronco foi relacionada com evolução desfavorável, o que não ocorreu com outros fatores envolvidos na regulação do ciclo celularMelanoma is the most lethal skin cancer. The outcome of melanoma is not predictable in most cases. Although the treatment for the primary tumor is well tolerated, there are no effective therapeutic options in disseminated disease. Efforts are being made in the search for tumoral markers that may predict outcome, increase the comprehension of melanoma pathogenesis, and may also help the search for molecular targets. In this issue, genetic studies concerning the regulation of cell cycle, including the G1-S checkpoint, are important. The retinoblastoma protein (pRb) pathway (p16, cyclin D1, CDK4 and pRb) and the p53 pathway (p53 and p21) are part of this regulation. Objectives: to verify the expression of p16, cyclin D1, CDK4, pRb, p53 and p21 in head, neck and trunk melanomas, and its correlation with prognosis. Method: Retrospective study approved by institution ethics committee. Fourtysix head, neck and trunk melanoma patients (67.3% men, mean age 57.7±15.8) treated by a single surgeon with minimum 2-years follow-up were enrolled. Clinical factors (primary tumor location, follow-up period, metastasis or related deaths), pathologic (histological subtype, Clark and Breslow index) and microarray immunohystochemical analysis of the cell cycle proteins p16, cyclin D1, CDK4, pRb, p53 and p21. Results: Location of the primary tumor was equal for head/neck and trunk (50% each). Thirteen patients were classified as Clark I (29.5%), five as Clark II (11.3%), 16 as Clark III (36.5%), 10 as IV (22.7%), none as Clark V. Mean Breslow measure was 0.96±1.01. Mean follow-up was 77±47 months. Eight patients (17.3%) had bad outcome, with six related deaths. Patients with worse outcome had a higher mean age at diagnosis (p=0,04). Expression of p16 was positive in 80%. Cyclin D1 was positive in 58.9%. CDK4 was positive in 43.5%. pRb was positive in 58.5%. p53 was positive in 53.6%. p21 was positive in 52.3%. Univariated analysis showed that p21 expression was related to worse outcome (p=0,04), while the other markers were not (p>0,05). Conclusion: p21 expression in head, neck and trunk melanomas was related to worse outcome. Expression of the other cell cycle regulators proteins was not
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Lo, Kin Yip. "Regulators of neurotrophin-mediated Trk signaling : SLAM-associated protein (SAP) and cyclin-dependent kinase 5 (Cdk5) /." View abstract or full-text, 2005. http://library.ust.hk/cgi/db/thesis.pl?BICH%202005%20LO.
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Bhaduri, Samyabrata. "Regulation of CDK1 Activity during the G1/S Transition in S. cerevisiae through Specific Cyclin-Substrate Docking: A Dissertation." eScholarship@UMMS, 2014. http://escholarship.umassmed.edu/gsbs_diss/871.
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Several cell cycle events require specific forms of the cyclin-CDK complexes. It has been known for some time that cyclins not only contribute by activating the CDK but also by choosing substrates and/or specifying the location of the CDK holoenzyme. There are several examples of B-type cyclins identifying certain peptide motifs in their specific substrates through a conserved region in their structure. Such interactions were not known for the G1 class of cyclins, which are instrumental in helping the cell decide whether or not to commit to a new cell cycle, a function that is non-redundant with B-type cylins in budding yeast. In this dissertation, I have presented evidence that some G1 cyclins in budding yeast, Cln1/2, specifically identify substrates by interacting with a leucine-proline rich sequence different from the ones used by B-type cyclins. These “LP” type docking motifs determine cyclin specificity, promote phosphorylation of suboptimal CDK sites and multi-site phosphorylation of substrates both in vivo and in vitro. Subsequently, we have discovered the substrate-binding region in Cln2 and further showed that this region is highly conserved amongst a variety of fungal G1 cyclins from budding yeasts to molds and mushrooms, thus suggesting a conserved function across fungal evolution. Interestingly, this region is close to but not same as the one implicated in B-type cyclins to binding substrates. We discovered that the main effect of obliterating this interaction is to delay cell cycle entry in budding yeast, such that cells begin DNA replication and budding only at a larger than normal cell size, possibly resulting from incomplete multi-site phosphorylation of several key substrates. The docking-deficient Cln2 was also defective in promoting polarized bud morphogenesis. Quite interestingly, we found that a CDK inhibitor, Far1, could regulate the Cln2-CDK1 activity partly by inhibiting the Cln2-substrate interaction, thus demonstrating that docking interactions can be targets of regulation. Finally, by studying many fungal cyclins exogenously expressed in budding yeast, we discovered that some have the ability to make the CDK hyper-potent, which suggests that these cyclins confer special properties to the CDK. My work provides mechanistic clues for cyclinspecific events during the cell cycle, demonstrates the usefulness of synthetic strategies in problem solving and also possibly resolves long-standing uncertainties regarding functions of some cell cycle proteins.
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Hsieh, Ricardo. "Expressão da proteína p16, ciclina D1, CDK4 e proteína do retinoblastoma no melanoma acral lentiginoso." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/5/5133/tde-04112008-162931/.
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INTRODUÇÃO: O melanoma acral lentiginoso (MAL) tem freqüência expressiva entre os casos de melanoma observados no nosso meio e difere dos outros tipos clinicopatológicos de melanoma cutâneos por não ter a exposição solar como fator predisponente. Poucos trabalhos da literatura enfocam as alterações dos genes supressores de tumores e a expressão de suas proteínas nas lesões de MAL. Por esses motivos propusemo-nos a realizar um estudo retrospectivo visando uma melhor compreensão das proteínas envolvidas na via p16 INK4a /ciclina D1/CDK4/pRb do ciclo celular, no MAL em casuística brasileira. MÉTODOS: Através de técnica de imunoistoquímica foi demonstrada a expressão das proteínas p16, ciclina D1, CDK4 e pRb em 32 lesões de MAL. Comparou-se a freqüência de expressão desses marcadores nos tumores delgados (espessura de até 1,0mm) e espessos (mais de 1,0 mm de espessura), assim como de acordo com a presença ou ausência de ulceração. RESULTADOS: Houve expressão de p16 em 78% das lesões, de ciclina D1 em 61,5%, CDK4 em 84% e pRb em 85% dos MAL analisados. O padrão de imunomarcação das células neoplásicas foi nuclear para todos os anticorpos. Expressão nuclear associada à citoplasmática foi observada em 76% dos tumores positivos para p16 e 81% dos casos positivos para CDK4. Não houve diferenças significativas entre as freqüências de expressão de cada um dos marcadores quando comparados de acordo com sua espessura (delgados e espessos) e presença de ulceração. CONCLUSÕES: A expressão de ciclina D1 e CDK4, nos melanomas acrais lentiginosos, pode ser considerada aberrante e reflexo de provável alteração na via supressora de tumores p16/ciclinaD1/CDK4/pRb. A expressão tecidual de p16 e pRb, demonstrada pela técnica imunoistoquímica, pode não refletir as prováveis alterações da via supressora de tumores estudada. Esses marcadores, isoladamente, não devem ser considerados como fatores prognósticos no melanoma acral lentiginosoINTRODUCTION: Acral lentiginous melanoma (ALM) has an expressive frequency between melanoma cases in our country, and it differs from the others clinical pathological types of cutaneous melanoma, because it does not have sun exposure as a predisposing factor. There are few publications in the literature addressing the expression of tumor suppressor pathway proteins in ALM. For these reasons we proposed to carry out a retrospective study aiming at a better understanding of p16 INK4a /cyclin D1/CDK4/pRb pathway involvement in ALM lesions. METHODS: Expression of p16, cyclin D1, CDK4 and pRB in 32 ALM lesions was displayed by immunohistochemistry. We compared the frequency of the expression of these markers in thin (thickness up to 1.0 mm) and thick lesions (thickness above 1.0 mm), as well as in accordance with the presence or absence of ulceration. RESULTS: 76% of the tumors were positive to p16 and 81% of the cases were positive to CDK4. There was no significant difference between the frequency of the expression of each marker when comparing in accordance with the thickness (thin and thick lesions) and the presence of ulceration. CONCLUSIONS: The expression of cyclin D1 and CDK4 in acral lentiginous melanoma may be considered aberrant and as reflex of a probable alteration in the p16/cyclin D1/CDK4/pRb tumor suppressor pathway. p16 and pRb tumor expression displayed by immunohistochemistry may not reflect probable alterations of the tumor suppressor pathway studied. The expression of these proteins, per se, may not be considered as prognostic factor in acral lentiginous melanoma
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Dann, Jeremiah J. "Immunological characterization and histone kinase activity of cyclin B1 and Cdk1 at G1 and G2/M phase of the cell division cycle in one-cell mouse embryos." Virtual Press, 2004. http://liblink.bsu.edu/uhtbin/catkey/1306852.
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Cyclin B1 is a cell cycle protein typically associated with the regulation of cellular division (mitosis). Previous studies in this laboratory involving preimplantation mouse embryos found that cyclin B1, or a cyclin B 1-related protein, were present at both G1 and G2/M phase of the cell cycle. Not only was cyclin Bi detected during G1 phase in this study, it was found to be present in higher concentrations at G1 phase through the first three cell cycles. These findings were unexpected, because most of the literature suggests that cyclin B1 is normally degraded during G1 phase. Using immunoprecipitation and immunoblot techniques, a more detailed study of cyclin B1 expression was inititated. Using two different primary antibodies direct against cyclin B1, a 48.97 kDa protein band, which is believed to be cyclin B1, was detected at both G1 and G2/M phases in 1-cell mouse embryos. Using another antibody directed against Cdk1, the kinase that forms a complex with cyclin B1 in order to direct the G2/M transition, a 37 kDa protein band was also detected at both G1 and G2/M phases in 1-cell mouse embryos. In order to determine whether cyclin B1 was present as a complex with Cdk1, immunoblotting with the anti-Cdk1 antibody. Again, a 37kDa protein band was detected at both G1 and G2/M phases. Finally, in order to determine whether the cyclin B1/Cdk1 complex exists in its active form, histone kinase assays were performed using anti-cyclin B1 immunoprecipitates. Kinase activity was detected in immunoprecipitates collected from G2/M phase 1-cell embryos, but no kinase activity was detected from immunoprecipitates collected from G1 phase 1-cell embryos. These data indicate that cyclin B1 and Cdk1 are present and exist as a complex in both G1 and G2/M phases of 1-cell mouse embryos, although the complex only appears to be active at the G2/M phase.Department of Biology
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Johansson, Jenny. "SNAP-25 and CDK5 as exocytotic regulators: consequences for synaptic function and insulin release /." Stockholm, 2007. http://diss.kib.ki.se/2007/978-91-7357-100-5/.
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Lam, Eric M. "IDENTIFICATION OF CYCLIN-DEPENDENT KINASE 5 IN T CELLS AND ITS ROLE IN REGULATING T CELL FUNCTION AND DIFFERENTIATION." Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1422014852.
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El, Dika Mohammed. "Régulation de la phase M du cycle cellulaire par CDK1, PP2A et CDC6." Thesis, Rennes 1, 2013. http://www.theses.fr/2013REN1S068.
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L'objectif de cette thèse est de mieux comprendre la régulation de la phase M du cycle cellulaire. Nos expériences ont été effectuées dans des extraits acellulaires d’embryons de Xenopus laevis. Tout d'abord, nous montrons que le moment de l'entrée en phase M est précisément déterminé par un équilibre entre l'activité de la protéine kinase CDK1 et l’activité d’une protéine phosphatase sensible à l'acide okadaïque, PP2A. Nous montrons également le rôle de la protéine CDC6 dans la régulation de l'entrée dans la première phase M embryonnaire. En effet, CDC6 inhibe CDK1 et à travers cette action régule la dynamique de cette kinase lors de l'entrée et de la progression en phase M. Ces résultats mettent en évidence un nouveau contrôle qui précise le moment du clivage embryonnaire. Ce contrôle joue un rôle clé dans la coordination entre les mécanismes de régulation du cycle cellulaire et le programme de développement de l'embryonThe aim of this thesis is to understand better the regulation of the M-phase of the cell cycle. Experiments were done in cell-free extracts of Xenopus laevis one-cell embryos. Firstly, we show that the timing of the M-phase entry is precisely determined by a balance between the activity of CDK1 kinase and okadaic acid sensitive phosphatase, mainly PP2A. Secondly, we show the role of CDC6 protein in regulation of the entry into the first embryonic M-phase. CDC6 inhibits CDK1 and through this action regulates the dynamic of this kinase upon M-phase entry and during M-phase progression. This mechanism discovered during my PhD allows controlling precisely the timing of embryonic cleavage. This control plays a key role in coordinating the cell cycle regulating machinery and the development program of the embryo
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Szeto, Sandy. "Phosphorylation of Filamin A by Cdk1/cyclin B1 Regulates Filamin A Subcellular Localization and is Important for Daughter Cell Separation." Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31732.
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In cell culture, entry into mitosis of many adherent mammalian cells is accompanied by substantial changes in cellular architecture. Flat, spread-out interphase cells detach from the extracellular matrix and become more spherical. These changes in cell shape are mediated by rearrangements in the actin cytoskeleton, a dynamic network of actin filaments that are organized by actin-binding proteins. Filamin A (FLNa) is a 280 kD actin-binding protein that crosslinks actin filaments into parallel bundles or three-dimensional orthogonal networks. We previously identified FLNa as an in vitro substrate of cyclin-dependent kinase 1 (Cdk1), a kinase that regulates entry into mitosis, and hypothesized that Cdk1 phosphorylation of FLNa regulates mitotic actin remodelling. Using mass spectrometry and a p-FLNa antibody, we show that FLNa is phosphorylated in vivo in HeLa cells on multiple Cdk1 sites, including serines 1084, 1459 and 1533. All three sites match the phosphorylation consensus sequence of Cdk1. We further show that p-FLNa is almost fully dephosphorylated by anaphase, consistent with it being a cell cycle-regulated substrate. Using a phospho-specific antibody, we find that p-FLNa has decreased cortical actin localization compared to total FLNa in mitotic cells. To investigate the functional role of mitotic FLNa phosphorylation, we mutated serines 1084, 1459 and 1533 to nonphosphorylatable alanine and expressed this FLNa mutant (FLNa-S1084A, S1459A, S1533A, referred to as “FLNa-AAA GFP”) in FLNa-deficient human M2 melanoma cells. FLNa-AAA GFP-expressing cells have enhanced FLNa-AAA GFP localization at sites of contact between daughter cells and this correlates with defects in cell division and impaired cell migration. Therefore, mitotic delocalization of cortical FLNa is critical for successful cell division and interphase cell behaviour.
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Borysov, Sergiy I. "B-Raf is an essential component of the mitotic machinery critical for activation of MAPK signaling during mitosis in Xenopus egg extracts." [Tampa, Fla] : University of South Florida, 2006. http://purl.fcla.edu/usf/dc/et/SFE0001759.
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Datar, Sanjeev Ashok. "Developmental regulation of growth and cell cycle progression in Drosophila melanogaster : a larval growth arrest screen, and molecular and genetic analysis of the cyclin D/Cdk4 complex /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/5008.
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