http://biblioteca.universia.net/verColeccion.do?id=3393 Mostrando recursos 1 - 20 de 9,978 es http://biblioteca.universia.net/img/logotipo.jpg http://biblioteca.universia.net/ http://biblioteca.universia.net/ficha.do?id=5313258 The activation of the cyclin-depdndent kinase Cdk1 at the transition from interphase to mitosis induces important changes in microtubule dynamics. Cdk1 phosphorylates a number of microtubule- or tubulin-binding proteins but, hitherto, tubulin itself has not been detected as a Cdk1 substrate. Here we show that Cdk1 phosphorylates ?-tubulin both in vitro and in vivo. Phosphorylation occurs on Ser172 of ?-tubulin, a site that is well conserved in evolution. Using a phosphopeptide antibody, we fi... Fourest-Lieuvin, Anne; Peris, Leticia; Gache, Vincent; Garcia-Saez, Isabel; Juillan-Binard, Céline; Lantez, Violaine; Job, Didier http://biblioteca.universia.net/ficha.do?id=5313259 Animal genomes each encode multiple highly conserved actin isoforms that polymerize to form the microfilament cytoskeleton. Previous studies of vertebrates and invertebrates have shown that many actin isoforms are restricted to either nonmuscle (cytoplasmic) functions, or to myofibril force generation in muscle cells. We have identified two temperature-sensitive and semidominant embryonic-lethal Caenorhabditis elegans mutants, each with a single mis-sense mutation in act-2, one of five C. ele... Willis, John H.; Munro, Edwin; Lyczak, Rebecca; Bowerman, Bruce http://biblioteca.universia.net/ficha.do?id=5313260 The Saccharomyces cerevisiae inhibitor of apoptosis (IAP) repeat protein Bir1 localizes as a chromosomal passenger. A deletion analysis of Bir1 identified two regions important for function. The C-terminal region is essential for growth, binds Sli15, and is necessary and sufficient for the localization of Bir1 as a chromosomal passenger. The middle region is not essential but is required to localize the inner kinetochore protein Ndc10 to the spindle during anaphase and to the midzone at telop... Widlund, Per O.; Lyssand, John S.; Anderson, Scott; Niessen, Sherry; Yates, John R.; Davis, Trisha N. http://biblioteca.universia.net/ficha.do?id=5313261 Slow Wallerian degeneration (WldS) mutant mice express a chimeric nuclear protein that protects sick or injured axons from degeneration. The C-terminal region, derived from NAD+ synthesizing enzyme Nmnat1, is reported to confer neuroprotection in vitro. However, an additional role for the N-terminal 70 amino acids (N70), derived from multiubiquitination factor Ube4b, has not been excluded. In wild-type Ube4b, N70 is part of a sequence essential for ubiquitination activity but its role is not ... Laser, Heike; Conforti, Laura; Morreale, Giacomo; Mack, Till G.M.; Heyer, Molly; Haley, Jane E.; Wishart, Thomas M.; Beirowski, Bogdan; Walker, Simon A.; Haase, Georg; Celik, Arzu; Adalbert, Robert; Wagner, Diana; Grumme, Daniela; Ribchester, Richard R.; Plomann, Markus; Coleman, Michael P. http://biblioteca.universia.net/ficha.do?id=5313262 Functional interactions between classical cadherins and the actin cytoskeleton involve diverse actin activities, including filament nucleation, cross-linking, and bundling. In this report, we explored the capacity of Ena/VASP proteins to regulate the actin cytoskeleton at cadherin-adhesive contacts. We extended the observation that Ena/vasodilator-stimulated phosphoprotein (VASP) proteins localize at cell–cell contacts to demonstrate that E-cadherin homophilic ligation is sufficient to recrui... Scott, Jeanie A.; Shewan, Annette M.; den Elzen, Nicole R.; Loureiro, Joseph J.; Gertler, Frank B.; Yap, Alpha S. http://biblioteca.universia.net/ficha.do?id=5313263 Shiga toxin (Stx) is composed of an A-moiety that inhibits protein synthesis after translocation into the cytosol, and a B-moiety that binds to Gb3 at the cell surface and mediates endocytosis of the toxin. After endocytosis, Stx is transported retrogradely to the endoplasmic reticulum, and then the A-fragment enters the cytosol. In this study, we have investigated whether toxin-induced signaling is involved in its entry. Stx was found to activate Syk and induce rapid tyrosine phosphorylation... Lauvrak, Silje Ugland; Wälchli, Sébastien; Iversen, Tore-Geir; Slagsvold, Hege Holte; Torgersen, Maria Lyngaas; Spilsberg, Bjørn; Sandvig, Kirsten http://biblioteca.universia.net/ficha.do?id=5313264 The septins are GTP-binding, filament-forming proteins that are involved in cytokinesis and other processes. In the yeast Saccharomyces cerevisiae, the septins are recruited to the presumptive bud site at the cell cortex, where they form a ring through which the bud emerges. We report here that in wild-type cells, the septins typically become detectable in the vicinity of the bud site several minutes before ring formation, but the ring itself is the first distinct structure that forms. Septin... Iwase, Masayuki; Luo, Jianying; Nagaraj, Satish; Longtine, Mark; Kim, Hyong Bai; Haarer, Brian K.; Caruso, Carlo; Tong, Zongtian; Pringle, John R.; Bi, Erfei http://biblioteca.universia.net/ficha.do?id=5313265 DDX1 bodies, cleavage bodies, Cajal bodies (CBs), and gems are nuclear suborganelles that contain factors involved in RNA transcription and/or processing. Although all four nuclear bodies can exist as distinct entities, they often colocalize or overlap with each other. To better understand the relationship between these four nuclear bodies, we examined their spatial distribution as a function of the cell cycle. Here, we report that whereas DDX1 bodies, CBs and gems are present throughout inte... Li, Lei; Roy, Ken; Katyal, Sachin; Sun, Xuejun; Bléoo, Stacey; Godbout, Roseline http://biblioteca.universia.net/ficha.do?id=5313266 The Ras–Raf–mitogen-activated protein kinase cascade is a key growth-signaling pathway, which uncontrolled activation results in transformation. Although the exact mechanisms underlying Raf-1 regulation remain incompletely understood, phosphorylation has been proposed to play a critical role in this regulation. We report here three novel epidermal growth factor-induced in vivo Raf-1 phosphorylation sites that mediate positive feedback Raf-1 regulation. Using mass spectrometry, we identified R... Balan, Vitaly; Leicht, Deborah T.; Zhu, Jun; Balan, Karina; Kaplun, Alexander; Singh-Gupta, Vinita; Qin, Jun; Ruan, Hong; Comb, Michael J.; Tzivion, Guri http://biblioteca.universia.net/ficha.do?id=5313267 Barrier-to-autointegration factor (BAF) is a conserved 10-kDa chromatin protein essential in proliferating cells. BAF dimers bind double-stranded DNA, histone H3, histone H1.1, lamin A, and transcription regulators, plus emerin and other LEM-domain nuclear proteins. Two-dimensional gel analysis showed that endogenous human and Xenopus BAF are posttranslationally modified by phosphorylation and potentially other modifications and that they are hyperphosphorylated during mitosis. The invariant ... Bengtsson, Luiza; Wilson, Katherine L. http://biblioteca.universia.net/ficha.do?id=5313268 Sphingolipids are required for many cellular functions including response to heat shock. We analyzed the yeast lcb1-100 mutant, which is conditionally impaired in the first step of sphingolipid biosynthesis and shows a strong decrease in heat shock protein synthesis and viability. Transcription and nuclear export of heat shock protein mRNAs is not affected. However, lcb1-100 cells exhibited a strong decrease in protein synthesis caused by a defect in translation initiation under heat stress c... Meier, Karsten D.; Deloche, Olivier; Kajiwara, Kentaro; Funato, Kouichi; Riezman, Howard http://biblioteca.universia.net/ficha.do?id=5313269 Eukaryotic cells reprogram their global patterns of gene expression in response to stress. Recent studies in Schizosaccharomyces pombe showed that the RNA-binding protein Csx1 plays a central role in controlling gene expression during oxidative stress. It does so by stabilizing atf1+ mRNA, which encodes a subunit of a bZIP transcription factor required for gene expression during oxidative stress. Here, we describe two related proteins, Cip1 and Cip2, that were identified by multidimensional p... Martín, Victoria; Rodríguez-Gabriel, Miguel A.; McDonald, W. Hayes; Watt, Stephen; Yates, John R.; Bähler, Jürg; Russell, Paul http://biblioteca.universia.net/ficha.do?id=5313270 The Saccharomyces cerevisiae SUV3 gene encodes the helicase component of the mitochondrial degradosome (mtEXO), the principal 3?-to-5? exoribonuclease of yeast mitochondria responsible for RNA turnover and surveillance. Inactivation of SUV3 (suv3?) causes multiple defects related to overaccumulation of aberrant transcripts and precursors, leading to a disruption of mitochondrial gene expression and loss of respiratory function. We isolated spontaneous suppressors that partially restore mitoch... Rogowska, Agata T.; Puchta, Olga; Czarnecka, Anna M.; Kaniak, Aneta; Stepien, Piotr P.; Golik, Pawel http://biblioteca.universia.net/ficha.do?id=5313271 Tetanus neurotoxin-insensitive vesicle-associated membrane protein (TI-VAMP)-mediated fusion of intracellular vesicles with the plasma membrane is crucial for neurite outgrowth, a pathway not requiring synaptobrevin-dependent exocytosis. Yet, it is not known how the TI-VAMP membrane trafficking pathway is regulated or how it is coordinated with cytoskeletal dynamics within the growth cone that guide neurite outgrowth. Here, we demonstrate that TI-VAMP, but not synaptobrevin 2, concentrates in... Alberts, Philipp; Rudge, Rachel; Irinopoulou, Theano; Danglot, Lydia; Gauthier-Rouvière, Cécile; Galli, Thierry http://biblioteca.universia.net/ficha.do?id=5313272 The focal adhesion-associated signaling protein HEF1 undergoes a striking relocalization to the spindle at mitosis, but a function for HEF1 in mitotic signaling has not been demonstrated. We here report that overexpression of HEF1 leads to failure of cells to progress through cytokinesis, whereas depletion of HEF1 by small interfering RNA (siRNA) leads to defects earlier in M phase before cleavage furrow formation. These defects can be explained mechanistically by our determination that HEF1 ... Dadke, Disha; Jarnik, Michael; Pugacheva, Elena N.; Singh, Mahendra K.; Golemis, Erica A. http://biblioteca.universia.net/ficha.do?id=5313273 In filamentous fungi, the stabilization of a polarity axis is likely to be a pivotal event underlying the emergence of a germ tube from a germinating spore. Recent results implicate the polarisome in this process and also suggest that it requires localized membrane organization. Here, we employ a chemical genetic approach to demonstrate that ceramide synthesis is necessary for the formation of a stable polarity axis in the model fungus Aspergillus nidulans. We demonstrate that a novel compoun... Li, Shaojie; Du, Liangcheng; Yuen, Gary; Harris, Steven D. http://biblioteca.universia.net/ficha.do?id=5313274 Sorting nexin 1 (SNX1) and SNX2 are the mammalian homologues of the yeast Vps5p retromer component that functions in endosome-to-Golgi trafficking. SNX1 is also implicated in endosome-to-lysosome sorting of cell surface receptors, although its requirement in this process remains to be determined. To assess SNX1 function in endocytic sorting of protease-activated receptor-1 (PAR1), we used siRNA to deplete HeLa cells of endogenous SNX1 protein. PAR1, a G-protein-coupled receptor, is proteolyti... Gullapalli, Anuradha; Wolfe, Breann L.; Griffin, Courtney T.; Magnuson, Terry; Trejo, JoAnn http://biblioteca.universia.net/ficha.do?id=5313275 Speckles are nuclear bodies that contain pre-mRNA splicing factors and polyadenylated RNA. Because nuclear poly(A) RNA consists of both mRNA transcripts and nucleus-restricted RNAs, we tested whether poly(A) RNA in speckles is dynamic or rather an immobile, perhaps structural, component. Fluorescein-labeled oligo(dT) was introduced into HeLa cells stably expressing a red fluorescent protein chimera of the splicing factor SC35 and allowed to hybridize. Fluorescence correlation spectroscopy (FC... Politz, Joan C. Ritland; Tuft, Richard A.; Prasanth, Kannanganattu V.; Baudendistel, Nina; Fogarty, Kevin E.; Lifshitz, Larry M.; Langowski, Jörg; Spector, David L.; Pederson, Thoru http://biblioteca.universia.net/ficha.do?id=5313276 The regulated localization of ?-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)-type glutamate receptors (AMPARs) to synapses is an important component of synaptic signaling and plasticity. Regulated ubiquitination and endocytosis determine the synaptic levels of AMPARs, but it is unclear which factors conduct these processes. To identify genes that regulate AMPAR synaptic abundance, we screened for mutants that accumulate high synaptic levels of the AMPAR subunit GLR-1 in Caenorha... Schaefer, Henry; Rongo, Christopher http://biblioteca.universia.net/ficha.do?id=5313277 N-cadherin is recruited to the heterotypic contact during transendothelial migration of melanoma cells in a coculture system with tumor cells seeded on top of a monolayer of endothelial cells. However, ?-catenin dissociates from N-cadherin and redistributes to the nucleus of transmigrating melanoma cells to activate gene transcription. In this report, we demonstrate that Src becomes activated at the heterotypic contact between the transmigrating melanoma cell and neighboring endothelial cells... Qi, Jianfei; Wang, Junfu; Romanyuk, Olena; Siu, Chi-Hung