http://biblioteca.universia.net/html_bura/verColeccion/params/id/29033.html Mostrando recursos 1 - 20 de 694 es http://biblioteca.universia.net/img/logotipo.jpg http://biblioteca.universia.net/ http://biblioteca.universia.net/html_bura/ficha/params/title/nuclear-inheritance-and-genetic-exchange-without-meiosis-in-the-binucleate/id/56678646.html The protozoan parasite Giardia intestinalis (also known as Giardia lamblia) is a major waterborne pathogen. During its life cycle, Giardia alternates between the actively growing trophozoite, which has two diploid nuclei with low levels of allelic heterozygosity, and the infectious cyst, which has four nuclei and a tough outer wall. Although the formation of the cyst wall has been studied extensively, we still lack basic knowledge about many fundamental aspects of the cyst, including the sour... Carpenter, Meredith L.; Assaf, Zoe June; Gourguechon, Stéphane; Cande, W. Zacheus http://biblioteca.universia.net/html_bura/ficha/params/title/regulation-of-sphingolipid-synthesis-through-orm1-and-orm2-in-yeast/id/56678645.html Sphingolipids are crucial components of membranes, and sphingolipid metabolites serve as signaling molecules. Yeast Orm1 and Orm2 belong to a conserved family of ER membrane proteins that regulate serine palmitoyltransferase, which catalyzes the first and rate-limiting step in sphingolipid synthesis. We now show that sphingolipid synthesis through Orm1 is a target of TOR signaling, which regulates cell growth in response to nutritional signals. Orm1 phosphorylation is dependent on the Tap42–p... Liu, Ming; Huang, Chunjuan; Polu, Surendranath R.; Schneiter, Roger; Chang, Amy http://biblioteca.universia.net/html_bura/ficha/params/title/chronic-photo-oxidative-stress-and-subsequent-mcp-1-activation-as/id/56678644.html Age-related macular degeneration (AMD) is the leading cause of blindness among the elderly in developed countries. Although pathogenic factors, such as oxidative stress, inflammation and genetics are thought to contribute to the development of AMD, little is known about the relationships and priorities between these factors. Here, we show that chronic photo-oxidative stress is an environmental factor involved in AMD pathogenesis. We first demonstrated that exposure to light induced phospholip... Suzuki, Mihoko; Tsujikawa, Motokazu; Itabe, Hiroyuki; Du, Zhao-Jiang; Xie, Ping; Matsumura, Nagakazu; Fu, Xiaoming; Zhang, Renliang; Sonoda, Koh-hei; Egashira, Kensuke; Hazen, Stanley L.; Kamei, Motohiro http://biblioteca.universia.net/html_bura/ficha/params/title/autophagy-and-cell-growth-–-the-yin-and-yang-of/id/56678643.html As a response to nutrient deprivation and other cell stresses, autophagy is often induced in the context of reduced or arrested cell growth. A plethora of signaling molecules and pathways have been shown to have opposing effects on cell growth and autophagy, and results of recent functional screens on a genomic scale support the idea that these processes might represent mutually exclusive cell fates. Understanding the ways in which autophagy and cell growth relate to one another is becoming i... Neufeld, Thomas P. http://biblioteca.universia.net/html_bura/ficha/params/title/pten-at-glance/id/56664358.html Shi, Yuji; Paluch, Benjamin E.; Wang, Xinjiang; Jiang, Xuejun http://biblioteca.universia.net/html_bura/ficha/params/title/supervillin-couples-myosin-dependent-contractility-to-podosomes-and-enables-their/id/56655688.html Podosomes are actin-rich adhesion and invasion structures. Especially in macrophages, podosomes exist in two subpopulations, large precursors at the cell periphery and smaller podosomes (successors) in the cell interior. To date, the mechanisms that differentially regulate these subpopulations are largely unknown. Here, we show that the membrane-associated protein supervillin localizes preferentially to successor podosomes and becomes enriched at precursors immediately before their dissolutio... Bhuwania, Ridhirama; Cornfine, Susanne; Fang, Zhiyou; Krüger, Marcus; Luna, Elizabeth J.; Linder, Stefan http://biblioteca.universia.net/html_bura/ficha/params/title/pdgfrβ-expression-and-function-in-fibroblasts-derived-from-pluripotent-cells/id/56655687.html Platelet-derived growth factor receptor-beta (PDGFRβ) is required for the development of mesenchymal cell types, and plays a diverse role in the function of fibroblasts in tissue homeostasis and regeneration. In this study, we characterized the expression of PDGFRβ in fibroblasts derived from human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), and showed that this expression is important for cellular functions such as migration, extracellular matrix production and as... Hewitt, Kyle J.; Shamis, Yulia; Knight, Elana; Smith, Avi; Maione, Anna; Alt-Holland, Addy; Sheridan, Steven D.; Haggarty, Stephen J.; Garlick, Jonathan A. http://biblioteca.universia.net/html_bura/ficha/params/title/micro-environmental-control-of-cell-migration-–-myosin-iia-is/id/56655686.html Recent evidence suggests that organization of the extracellular matrix (ECM) into aligned fibrils or fibril-like ECM topographies promotes rapid migration in fibroblasts. However, the mechanisms of cell migration that are altered by these changes in micro-environmental topography remain unknown. Here, using 1D fibrillar migration as a model system for oriented fibrillar 3D matrices, we find that fibroblast leading-edge dynamics are enhanced by 1D fibrillar micropatterns and demonstrate a depe... Doyle, Andrew D.; Kutys, Matthew L.; Conti, Mary Anne; Matsumoto, Kazue; Adelstein, Robert S.; Yamada, Kenneth M. http://biblioteca.universia.net/html_bura/ficha/params/title/functional-differences-between-kindlin-1-and-kindlin-2-in-keratinocytes/id/56655685.html Integrin-β1-null keratinocytes can adhere to fibronectin through integrin αvβ6, but form large peripheral focal adhesions and exhibit defective cell spreading. Here we report that, in addition to the reduced avidity of αvβ6 integrin binding to fibronectin, the inability of integrin β6 to efficiently bind and recruit kindlin-2 to focal adhesions directly contributes to these phenotypes. Kindlins regulate integrins through direct interactions with the integrin-β cytoplasmic tail and keratinocyt... Bandyopadhyay, Aditi; Rothschild, Gerson; Kim, Sean; Calderwood, David A.; Raghavan, Srikala http://biblioteca.universia.net/html_bura/ficha/params/title/keratin-8-phosphorylation-regulates-keratin-reorganization-and-migration-of-epithelial/id/56655684.html Cell migration and invasion are largely dependent on the complex organization of the various cytoskeletal components. Whereas the role of actin filaments and microtubules in cell motility is well established, the role of intermediate filaments in this process is incompletely understood. Organization and structure of the keratin cytoskeleton, which consists of heteropolymers of at least one type 1 and one type 2 intermediate filament, are in part regulated by post-translational modifications. ... Busch, Tobias; Armacki, Milena; Eiseler, Tim; Joodi, Golsa; Temme, Claudia; Jansen, Julia; von Wichert, Götz; Omary, M. Bishr; Spatz, Joachim; Seufferlein, Thomas http://biblioteca.universia.net/html_bura/ficha/params/title/vangl2-regulates-membrane-trafficking-of-mmp14-to-control-cell-polarity/id/56655683.html Planar cell polarity (PCP) describes the polarized orientation of cells within the plane of a tissue. Unlike epithelial PCP, the mechanisms underlying PCP signaling in migrating cells remain undefined. Here, the establishment of PCP must be coordinated with dynamic changes in cell adhesion and extracellular matrix (ECM) organization. During gastrulation, the membrane type-1 matrix metalloproteinase (MT1-MMP or MMP14) is required for PCP and convergence and extension cell movements. We report ... Williams, B. Blairanne; Cantrell, V. Ashley; Mundell, Nathan A.; Bennett, Andrea C.; Quick, Rachel E.; Jessen, Jason R. http://biblioteca.universia.net/html_bura/ficha/params/title/lamins-at-glance/id/56655682.html Ho, Chin Yee; Lammerding, Jan http://biblioteca.universia.net/html_bura/ficha/params/title/conserved-role-of-iqgap1-in-regulating-tor-complex-1/id/56586042.html Defining the mechanisms that control cell growth and division is crucial to understanding cell homeostasis, which impacts human diseases such as cancer and diabetes. IQGAP1, a widely conserved effector and/or regulator of the GTPase CDC42, is a putative oncoprotein that controls cell proliferation; however, its mechanism in tumorigenesis is unknown. The mechanistic target of rapamycin (mTOR) pathway, the center of cell growth control, is commonly activated in human cancers, but has proved to ... Tekletsadik, Yemsrach K.; Sonn, Robert; Osman, Mahasin A. http://biblioteca.universia.net/html_bura/ficha/params/title/disruption-of-kif3a-in-osteoblasts-results-in-defective-bone-formation/id/56586041.html We investigated whether Kif3a in osteoblasts has a direct role in regulating postnatal bone formation. We conditionally deleted Kif3a in osteoblasts by crossing osteocalcin (Oc; also known as Bglap)–Cre with Kif3aflox/null mice. Conditional Kif3a-null mice (Kif3aOc-cKO) had a 75% reduction in Kif3a transcripts in bone and osteoblasts. Conditional deletion of Kif3a resulted in the reduction of primary cilia number by 51% and length by 27% in osteoblasts. Kif3aOc-cKO mice developed osteopenia b... Qiu, Ni; Xiao, Zhousheng; Cao, Li; Buechel, Meagan M.; David, Valentin; Roan, Esra; Quarles, L. Darryl http://biblioteca.universia.net/html_bura/ficha/params/title/erα-mediated-repression-of-pro-inflammatory-cytokine-expression-by-glucocorticoids/id/56586040.html Most glandular tissues comprise polarized epithelial cells organized around a single central lumen. Although there is active research investigating the molecular networks involved in the regulation of lumenogenesis, little is known about the extracellular factors that influence lumen formation and maintenance. Using a three-dimensional culture system of epithelial endometrial cells, we have revealed a new role for pro-inflammatory cytokines such as TNFα and IL1α in the formation and, more imp... Eritja, Nuria; Mirantes, Cristina; Llobet, David; Masip, Gemma; Matias-Guiu, Xavier; Dolcet, Xavi http://biblioteca.universia.net/html_bura/ficha/params/title/znrf2-is-released-from-membranes-by-growth-factors-and-together/id/56561673.html Here, we describe a phosphorylation-based reverse myristoyl switch for mammalian ZNRF2, and show that this E3 ubiquitin ligase and its sister protein ZNRF1 regulate the Na+/K+ pump (Na+/K+ATPase). N-myristoylation localizes ZNRF1 and ZNRF2 to intracellular membranes and enhances their activity. However, when ZNRF2 is phosphorylated in response to agonists including insulin and growth factors, it binds to 14-3-3 and is released into the cytosol. On membranes, ZNRF1 and ZNRF2 interact with the ... Hoxhaj, Gerta; Najafov, Ayaz; Toth, Rachel; Campbell, David G.; Prescott, Alan R.; MacKintosh, Carol http://biblioteca.universia.net/html_bura/ficha/params/title/increased-retinoic-acid-levels-through-ablation-of-cyp26b1-determine-the/id/56559965.html The process by which the periderm transitions to stratified epidermis with the establishment of the skin barrier is unknown. Understanding the cellular and molecular processes involved is crucial for the treatment of human pathologies, where abnormal skin development and barrier dysfunction are associated with hypothermia and perinatal dehydration. For the first time, we demonstrate that retinoic acid (RA) levels are important for periderm desquamation, embryonic skin differentiation and barr... Okano, Junko; Lichti, Ulrike; Mamiya, Satoru; Aronova, Maria; Zhang, Guofeng; Yuspa, Stuart H.; Hamada, Hiroshi; Sakai, Yasuo; Morasso, Maria I. http://biblioteca.universia.net/html_bura/ficha/params/title/dystrophin-compromised-sarcoglycan-δ-knockout-diaphragm-requires-full-wild-type/id/56559964.html Limb-girdle muscular dystrophy-2F (LGMD-2F) is an incurable degenerative muscle disorder caused by a mutation in the sarcoglycan-δ (SGδ)-encoding gene (SGCD in humans). The lack of SGδ results in the complete disruption of the sarcoglycan complex (SGC) in the skeletal and cardiac muscle within the larger dystrophin–glycoprotein complex (DGC). The long-term consequences of SG ablation on other members of the DGC are currently unknown. We produced mosaic mice through the injection of wild-type ... Vitale, Joseph M.; Schneider, Joel S.; Beck, Amanda J.; Zhao, Qingshi; Chang, Corey; Gordan, Richard; Michaels, Jennifer; Bhaumik, Mantu; Fraidenraich, Diego http://biblioteca.universia.net/html_bura/ficha/params/title/the-ipla-ca2-channel-of-dictyostelium-discoideum-is-necessary-for/id/56559963.html During aggregation of Dictyostelium discoideum, nondissipating, symmetrical, outwardly moving waves of cAMP direct cells towards aggregation centers. It has been assumed that the spatial and temporal characteristics of the front and back of each cAMP wave regulate both chemokinesis and chemotaxis. However, during the period preceding aggregation, cells acquire not only the capacity to chemotax in a spatial gradient of cAMP, but also in a spatial gradient of Ca2+. The null mutant of the putati... Lusche, Daniel F.; Wessels, Deborah; Scherer, Amanda; Daniels, Karla; Kuhl, Spencer; Soll, David R. http://biblioteca.universia.net/html_bura/ficha/params/title/involvement-of-actin-polymerization-in-podosome-dynamics/id/56559962.html Podosomes, which are formed by different monocyte derivatives, are small adhesion structures whose coordinated dynamics and cytoskeletal reorganization drive their motile and invasive features. Using live-cell microscopy, we explored the temporal molecular steps of the de novo assembly and disassembly of podosomes in cultured osteoclasts. We demonstrate here that the earliest visible step in podosome assembly is the local accumulation of the plaque protein paxillin, along with cortactin, whic... Luxenburg, Chen; Winograd-Katz, Sabina; Addadi, Lia; Geiger, Benjamin