Actin cytoskeletal regulation is of critical importance for a number of diverse cellular functions, including cell motility, endocytosis, cell division and transcription. Tight regulation of actin is critical for many aspects of cancer biology and in particular invasion and metastasis. ADF/cofilins are among the most important actin regulatory proteins. Mammals have three highly conserved members, ADF, CFL1 and CFL2, which regulate actin dynamics by severing and depolymerizing actin filaments. Despite a huge literature on the roles of ADF/cofilins in actin treadmilling and cell migration in vitro and in cancer cell behavior during invasion, very little is known about their collective roles in tissue homeostasis. By employing genetic knock-outs of ADF, in conjunction with conditional depletion of CFL1 using a Cre-LoxP system under the control of the keratin 14 promoter, we were able to study the effects of ADF/CFL1 loss in vivo in the mouse epidermis. Furthermore, by generating ADF-null squamous cell carcinoma (SCC) cell lines and by transiently downregulating CFL1 with RNAi, we were able to investigate further the cellular responses after ADF/CFL1 depletion in vitro. Co-depletion of ADF and CFL1 from the mouse epidermis triggered loss of tissue homeostasis characterized by abnormal thickening of the tissue, actin filament accumulation and nuclear deformation. Loss of ADF/CFL1 in cultured malignant keratinocytes also led to aberrant cell morphology accompanied by unrestrained accumulation of actin stress fibers tethered to enlarged focal adhesions. Enhanced SRF/MAL-mediated transcription fuels this uncontrolled actin polymerization which is also mediated by Arp3. Furthermore, these actin filaments are decorated with phospho-myosin light chain, which indicates their contractile nature. As a consequence, the increased intracellular acto-myosin tension results in nuclear deformation, which is promoted by the deregulated actin filaments tethered to the nuclear envelope via the linker of nucleoskeleton and cytoskeleton (LINC) complex. Overall, we describe new conceptual insight into the cellular functions of ADF/cofilins. We show that their activities are essential for the dynamic regulation of contractile actin filaments that, if left unchecked, lead to loss of cellular homeostasis and cell death promoted by loss of nuclear integrity. Additionally, the critical roles of nuclear actin and actin-associated proteins have recently started being appreciated. Thus, for the first time we set out to investigate new functions of cofilins in the nucleus using proteomics, and identify new cofilin binding partners that implicate them in novel cellular pathways, expanding our knowledge on these small actin-binding proteins.

I uppsatsen undersöks effektiviteten av de tre nordiska aktieindexterminerna OMXS30, OBX och OMXC20 vars underliggande index representerar den svenska, norska respektive den danska aktiemarknaden. Analysen baseras på den svaga formen av den effektiva marknadshypotesen och den närbesläktade random walk hypotesen. Aktieindexterminerna undersöks under perioden januari 1997 till december 2008 samt under perioder då den nordiska marknaden karaktäriseras av bull och bear perioder. Testresultaten av Augmented Dickey-Fuller (ADF) samt Kwiatkowski, Phillips, Schmidt och Shin (KPSS) testet tyder på att aktieindexterminerna följer en random walk och att nordiska aktieindexterminer är effektiva under den undersökta perioden. Då testen utförs för de kortare bull och bear perioderna erhålls motsägelsefulla resultat vilket medför att slutsatser om huruvida aktieindexterminerna är effektiva under dessa perioder ej kan dras.

Durant mon travail de thèse, j'ai étudié le rôle central de l'ADF/cofiline, une protéine qui se lie au cytosquelette d'actine, décore spécifiquement les parties 'âgées' des filaments d'actine, diminue localement par un facteur 5 la rigidité du filament et provoque la fragmentation du filament à l'interface entre les sections nues et décorées. Dans ma première étude (Suarez et al., Current Biology, 2011), j'ai utilisé la microscopie à onde évanescente et une ADF/cofiline fluorescente pour démontrer que l'ADF/cofiline est un marqueur de l'état nucléotidique (ATP, ADP-Pi ou ADP) des sous-unités d'un filament d'actine en cours de polymérisation. De plus, l'ADF/cofiline, en accélérant la dissociation du phosphate inorganique (Pi), limite la taille du cap ATP/ADP-Pi du filament d'actine, sans toutefois le réduire à une taille zéro. Des analyses statistiques sur filaments isolés établissent une corrélation parfaite entre la densité de fixation de l'ADF/cofiline et son efficacité de fragmentation. Paradoxalement, l'efficacité de fragmentation est maximale pour une densité d'ADF/cofiline de 0.5. Ceci est confirmé par des analyses supplémentaires qui montrent que les sites de fragmentation du filament coïncident avec la position des frontières entre zones décorées et zones nues. Les conséquences de ce dernier résultat paradoxal sont l'objet de ma seconde étude (McCullough et al., 2011, Biophysical Journal). En combinant différentes sources d'ADF/cofilines (vertébré et levure) et d'actines (vertébré et levure), nous montrons, sur les quatre couples actine-ADF/cofiline possibles, qu'il existe une très forte corrélation entre (1) l'efficacité de fragmentation (qui dépend de la combinaison entre actine et ADF/cofiline) et (2) la déformation du filament, mesurée à la frontière entre zone décorée et zone nue. Au cours de ma troisième étude (Reymann et al., Molecular Biology of the Cell, 2011), nous montrons que le mécanisme de fragmentation ADF/cofiline-dépendant, établi à l'échelle d'un filament isolé, peut s'appliquer aussi à l'échelle d'une comète d'actine qui comporte un réseau complexe de filaments. Mon travail de thèse a montré que le mode d'action de l'ADF/cofiline se situe à l'intersection entre mécanismes microscopiques et macroscopiques, d'une part, et entre chimie et physique, d'autre part. Les caractéristiques microscopiques des interactions de cette protéine avec un filament d'actine isolé sont fondamentales pour expliquer des évènements macroscopiques, comme la fragmentation de filaments ou de structures complexes. D'autre part, nous avons montré comment les propriétés chimiques de l'ADF/cofiline modifient les propriétés physiques locales du filament et conduisent à la fragmentation. L'ADF/cofiline a un rôle central pour l'intégration de mécanismes physico-chimiques, à l'échelle microscopique, afin d'assurer un comportement cohérent à l'échelle de la cellule.

No description available.

Les oncogènes Bcr-Abl (p190bcr-abl et p210bcr-abl) sont issus d'une translocation chromosomique t(9,22) qui fusionne en phase les gènes bcr et c-abl. p210bcr-abl est généralement responsable de la Leucémie Myéloïde Chronique (LMC) alors que p190bcr-abl induit un sous type de Leucémie Aigue Lymphoblastique (LAL). La seule différence structurale entre ces deux protéines est la présence d'un domaine DH/PH au sein de p210bcr-abl activateur spécifique de RhoA. L'expression de Bcr-Abl dans la lignée Ba/F3 est associée au déclenchement d'une migration spontanée, dépourvue de directionnalité, sous la dépendance de la GTPase Rac1.L'activation de RhoA, spécifique des cellules Ba/F3p210, est associée à un phénotype migratoire amœboïde dans une matrice de Matrigel™ en 3D où les cellules Ba/F3p190 dépourvues de RhoA activé, présentent une mobilité de type roulement. Dans ce travail, nous avons mis en évidence que l'activation spécifique de ROCK1 par RhoA détermine deux voies parallèles et mutuellement indispensables pour le mouvement amœboïde : 1) la voie de la Chaine Légère de Myosine (CLM) 2) celle des protéines de la famille ADF (Actin Depolymerizing Factor), et plus particulièrement l'isoforme ADF/destrine. Nous démontrons également l'existence d'invadopodes spécifiquement dans les cellules Ba/F3p190, dont la formation est sous la dépendance de l'absence d'activation de RhoA corrélée à une augmentation de l'activation de Cdc42. Enfin nous démontrons que la voie de signalisation RhoA/ROCK est spécifiquement activée dans les progéniteurs hématopoïétiques CD34+ issus de patients atteints de LMC et ce, indépendamment de l'activité tyrosine kinase de Bcr-Abl. / Bcr-Abl chimeric oncogenes (p190bcr-abl and p210bcr-abl) result from the t(9,22) chromosomal translocation that fuse the bcr and the c-abl genes. p210bcr-abl and p190bcr-abl are associated with Chronic Myelogenous Leukemia (CML) and a subset of Acute Lymphoblastic Leukemia (ALL) respectively. The only difference between these two chimeras is the presence of a specific RhoA-GEF domain in the p210bcr-abl oncogene. Bcr-Abl expression in Ba/F3 lymphoblasts induces spontaneous migration of these cells without apparent directionality. Motility triggering of Bcr-Abl-expressing Ba/F3 depends on the RhoGTPase Rac1.RhoA activity is associated with a typical amoeboid movement of Ba/F3p210 cells embedded in Matrigel™ 3D matrix, whereas the Ba/F3p190 cells, devoid of RhoA activity, display a rolling-type motility. In this work we showed that activation of the RhoA effector ROCK1 triggers two parallel pathways which are both necessary for amoeboid movement: 1) the Myosin Light chain (MLC) pathway 2) ADF family proteins (Actin Depolymerizing Factor) pathway, specifically the ADF/destrin isoform. Besides, we showed that Ba/F3p190 cells could assemble invadopodia-like structures. The formation of these structures is driven by the reduction of RhoA activity associated with the absence of the DH/PH domain in p190bcr-abl and correlates with an increase in Cdc42 activity. We finally demonstrated that the RhoA/ROCK pathway is constitutively activated in CD34+ cells isolated from CML patients while not in their normal counterparts. We also demonstrated that this activation is independent of the tyrosine Kinase activity of Bcr-Abl.

Made available in DSpace on 2016-03-15T19:30:44Z (GMT). No. of bitstreams: 1 Andre Wakamatsu.pdf: 3217691 bytes, checksum: 1c24d8cfb446c335c1b83266a22241de (MD5) Previous issue date: 2011-02-17 / Fundo Mackenzie de Pesquisa / The competitive strategy of a firm is defined by choosing one alternative over the rivals, from differentiated activities set to deliver a product or service (strategic positioning). If firms cooperate or collude with each other, they don t have choices conflict and the strategy would not be necessary. To verify if several firms in the same market are in collusion, the responsible economic defense agencies considers the hypothesis that firms are in monopolistic competition (known as the hypothetical monopolist approach). Coe, Krause (2008) made an empirical study with the methods commonly used to evaluate the price-based approaches using synthetic data obtained from a market simulation with differentiated products. However,the authors consider a market structure where firms try to maximize profit without the constraint that, in long run, economic profit is zero. The aim of this work was to generate synthetic data considering the monopolistic competition and analyze if two econometric tests,Augmented Dickey-Fuller (ADF) and co-integration, can be used to delimitate this market structure. Since it was considered that the market consists of firms that have products with substitutes, the trends of the firms prices was stationary over time and therefore the price series should be correlated and co-integrated. In addition, it was analyzed what would happen to the equilibrium prices when an importing company, for example, a product that would be considered a substitute by the consumers, but had no problems related to the increased cost of production in the domestic market. It was observed that the importing firms, when its price was lower than that the other firms in the domestic market, tend to slow the increase of the firms price. / A estratégia competitiva de uma empresa significa escolher uma alternativa em relação aos concorrentes, a partir de um conjunto diferenciado de atividades, para a entrega de um produto ou serviço de valor único (posicionamento estratégico). Se as empresas não tivessem conflito de escolhas, a estratégia não seria necessária. Uma forma delas não terem conflito de escolha é ter uma conduta de cooperação ou conluio. Para se verificar se diversas empresas em um mesmo mercado estão em colusão, os órgãos responsáveis pela defesa econômica considera a hipótese de que as empresas estão em concorrência monopolística (conhecida como abordagem do monopolista hipotético). Coe; Krause (2008) fizeram um estudo empírico com relação aos métodos comumente utilizados para avaliar as abordagens baseadas em preço por meio do uso de dados sintéticos obtidos de uma simulação de um mercado com produtos diferenciados. Entretanto, os autores consideraram uma estrutura de mercado em que as empresas tentam maximizar o lucro, sem a restrição de manter o lucro econômico igual a zero. Neste trabalho, a proposta foi gerar dados sintéticos considerando que as empresas estão em competição monopolística e analisar se dois testes econométricos, Dickey-Fuller ampliado (ADF) e co-integração, servem para delimitar este tipo de estrutura. Uma vez que foi considerado que o mercado é composto de empresas que tem produtos substitutos próximos, a evolução dos preços exercidos pelas empresas foi estacionária ao longo do tempo e, portanto, as séries dos preços eram correlacionadas e co-integradas. Além disso, também foi analisado o que ocorreria com os preços de equilíbrio quando uma empresa importadora, por exemplo,importasse um produto que seria considerado um substituto direto pelos consumidores, mas não tivesse os problemas relacionados ao aumento do custo de produção no mercado nacional.Foi observado que uma empresa importadora, quando exerce um preço menor do que o exercido pelas empresas do mercado nacional, tende a diminuir o ritmo de aumento do preço das outras empresas, disciplinando-as.

歐元的問世，代表的是從1970年代固定匯率被打破以來，世界金融體系最大一次的變革，其對全球之金融及社會文化有很深遠的意義；因此，有關美國與歐元區間之匯率、利率及物價關係的探討遂成為國際金融市場所關心的焦點之一；本文以Frankel (1992)所提出衡量國際間資本移動性的三種利率平價說：拋補利率平價說(Covered Interest Parity，CIP) 、無拋補利率平價說 (Uncovered Interest Parity，UIP)、實質利率平價說 (Real Interest Parity，RIP)為基礎，來檢驗此三種利率平價說是否成立。在實證方法上，本文以Dickey & Fuller (1979,1981)之ADF單根檢定來確定變數之數列特性，再採Johansen (1988)之最大概似估計法，對CIP、UIP與RIP進行實證分析。實證結果發現，於1999 年 1 月至 2004 年 7 月期間，美國與歐元區間 CIP 與 UIP 同時成立，表示當兩國資產報酬率有差異時，可以經由國際間資本的移動，使得報酬率最後有趨於相等的傾向；並且接受遠期匯率為未來即期匯率的不偏估計值之虛無假設，顯示歐元與美元間外匯市場具有效率性。另外，本文之實證結果並不支持 RIP 的成立，其有可能歐元區與美國在編制物價指數時，所使用的物價項目和比重情況不同而異，因此難以表示出公正之匯價；再者由於現實之貨幣、商品市場之不完全，與人民不一定能完全預期及存在貨幣幻覺等許許多多未考慮因素下，故在諸多驗證 RIP之文獻中，亦大多顯示無法找到其均衡之平價關係。 / The emergence of Eurodollar exemplified a significant reformation in the world financial system since the fixed rate had been broken in 1970, which brings far-reaching significance to the global finance and social culture. Therefore some discussions on exchange rate, interest rate and price relationship in the range of US Dollar and Eurodollar are one of focuses the international financial market concerns; On the basis of the three kinds of interest rate parity Frankel brought forward (1992) including Covered Interest Parity (CIP), Uncovered Interest Parity (UIP) and Real Interest Parity (RIP), this research mainly proves their feasibility. For the empirical methods, the Dickey & Fuller (1979, 1981)’s ADF unit root test was used to confirm the characteristics of variable series in this research; additionally, Johansen’s maximum likelihood method (1988) was adopted to do the empirical analysis on CIP, UIP and RIP. Based on the empirical results, we found out that the CIP and UIP are tenable simultaneously in the range of tenable US Dollar and Eurodollar from 1999 January to 2004 July. That means when return on asserts between two counties has some differences, it would become towards equality lastly on the basis of international capital mobility. And the null hypothesis that the forward rate is an unbiased predictor of the future spot rate can be employed, revealing the foreign exchange market in the range of Eurodollar and US Dollar has certain efficiency. Additionally, The empirical results of this research do not support the RIP, because it would vary with different prices and proportion used while making the price index in the range of Eurodollar and US Dollar, and cannot present equitable exchange rate; furthermore, because of imperfect current currency and commodity markets, and many unconsidered factors such as people’ incompletely anticipation and money illusion, most researches for validating RIP fail to find out its balanced parity relation.

Housing bubbles could have a great impact on the economy of a country, especially for a country as large as China. Therefore, it is necessary to evaluate the housing bubble situation of a region. Based on the classification of cities, this research has selected Yangzhou as the main research sample to predict the overall situation of housing bubble in third-level cities in China. The paper integrates the relevant theories and methods of the housing bubble research mentioned in the literature, and seeks out a set of suitable real estate bubble research methods: using ADF test, EG cointegration analysis to see whether the indicators are suitable as variables in the Granger causality test and regression analysis, and then perform regression analysis on the appropriate variables and housing prices to judge the real estate bubble. Also, the result of Yangzhou is applied to compare with that of Beijing and Shanghai so as to get the difference of real estate markets between first- and third-level cities. / Bostadsbubblor kan ge allvarlig inverkan på ett lands ekonomi, särskilt för ett så stort land som Kina. Därför är det nödvändigt att utvärdera om eventuella bostadsbubblor förekommer i olika regioner. I detta arbete analyseras förekomsten av en bostadsbubbla i en av Kinas städer i den tredje storleksklassen enligt det kinesiska klassificeringssystemet. Studieobjektet som valts är Yangzhou. I uppsatsen diskuteras de relevanta teorier och metoder som förekommer i litteraturen för analys av bostadsbubblor och ett antal metoder tillämpas. ADF-test och Engel-Grainer-kointegration används för att avgöra vilka av de tillgängliga marknadsindikatorerna som är lämpliga att använda vid test av Granger-kausalitet och i regressionsanalyser. Regressioner med de utvalda variablerna görs sedan mot bostadspriser för att erhålla mått på förekomsten av en bostadsbubbla. De empiriska resultaten från studien jämförs också med resultat för Beijing and Shanghai för att påvisa skillnader mellan marknaderna i städer av första respektive tredje storleksklassen.

本研究利用ADF單根檢定以及新觀點的季節性單根檢定做為分析工具，去檢測期貨巿場與現貨巿場是否存在一長期均衡關係。研究對象共有十種，分別為：能源期貨－輕原油、煤油，外匯期貨－日圓、瑞士法郎（對美元），短期利率期貨－一個月期倫敦銀行拆款利率、90天期美國國庫券，公債期貨－2年的美國中期公債、15至30年的美國長期公債，S&P500指數期貨，金屬期貨－高等級銅期貨。 過去檢測長期均衡關係所使用的單根檢定觀點假設其他頻率的單根並不存在，因此當拒絕虛無假設時，我們無法確知拒絕的原因是資料真的沒有單根的存在，抑或是資料具有季節性現象，因此納入季節性考量的HEGY檢定法，將是比較一般化的檢定方法，而且因為HEGY能夠同時檢定季節性及某些非季節性單根的存在與否，而不必假設所有季節性頻率的單根皆同時存在，所以ADF單根檢定法可視為HEGY季節性單根檢定法之特例，因此一般來說，HEGY檢定法之檢定力較ADF單根檢定法為高。 而本文實證結果亦證明，ADF單根檢定法的確無法檢定出季節性單根的有無，當季節性因素存在時，使用ADF單根檢定將可能導致錯誤的推論。

Cool season perennial grasses are the foundation of equine nutrition in the transition zone. The objective of this study was to evaluate forage quality using ADF, NDF, IVTDMD, CP, WSC, and ESC and changes in vegetative swards seasonally, diurnally, across species (Kentucky bluegrass, tall fescue, orchardgrass, and perennial ryegrass) and cultivar. This study was conducted in 2015 and 2017 and plots were maintained vegetatively with two to four week mowing. Morning and afternoon sample collection occurred monthly during the growing season. Samples were flash frozen; freeze dried, ground, and scanned using Near Infrared Reflectance Spectroscopy (NIRS) to predict forage quality. There was a significant year effect; therefore year was analyzed separately. Generally, ADF and NDF were highest for Kentucky bluegrass (30 and 52%), lowest for perennial ryegrass (25 and 46%), and tall fescue and orchardgrass were inconsistent. Crude protein was variable across species and season, ranging 10 to 25%. ADF and NDF concentrations were higher in the morning; IVTDMD, WSC, and ESC were higher in the afternoon; and CP was similar diurnally. In conclusion, forage quality in vegetative cool season grass pastures was sufficient to meet the nutritional needs of most equines, but varied seasonally, diurnally, across species, and cultivar.