These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Atg6 is required for multiple vesicle trafficking pathways and hematopoiesis in Drosophila  

PubMed Central

Atg6 (beclin 1 in mammals) is a core component of the Vps34 complex that is required for autophagy. Beclin 1 (Becn1) functions as a tumor suppressor, and Becn1+/- tumors in mice possess elevated cell stress and p62 levels, altered NF-?B signaling and genome instability. The tumor suppressor function of Becn1 has been attributed to its role in autophagy, and the potential functions of Atg6/Becn1 in other vesicle trafficking pathways for tumor development have not been considered. Here, we generate Atg6 mutant Drosophila and demonstrate that Atg6 is essential for autophagy, endocytosis and protein secretion. By contrast, the core autophagy gene Atg1 is required for autophagy and protein secretion, but it is not required for endocytosis. Unlike null mutants of other core autophagy genes, all Atg6 mutant animals possess blood cell masses. Atg6 mutants have enlarged lymph glands (the hematopoietic organ in Drosophila), possess elevated blood cell numbers, and the formation of melanotic blood cell masses in these mutants is not suppressed by mutations in either p62 or NF?B genes. Thus, like mammals, altered Atg6 function in flies causes hematopoietic abnormalities and lethality, and our data indicate that this is due to defects in multiple membrane trafficking processes. PMID:23406899

Shravage, Bhupendra V.; Hill, Jahda H.; Powers, Christine M.; Wu, Louisa; Baehrecke, Eric H.

2013-01-01

2

Fluctuation of multiple metabolic pathways is required for Escherichia coli in response to chlortetracycline stress.  

PubMed

Bacterial antibiotic resistance has become a worldwide challenge with the overuse and misuse of drugs. Several mechanisms for the resistance are revealed, but information regarding the bacterial global response to antibiotics is largely absent. In this study, we characterized the differential proteome of Escherichia coli K12 BW25113 in response to chlortetracycline stress using isobaric tags for relative and absolute quantitation labeling quantitative proteomics technology. A total of 723 proteins including 10,763 peptides were identified with 184 decreasing and 147 increasing in abundance by liquid chromatography matrix assisted laser desorption ionization mass spectrometry. Most interestingly, crucial metabolic pathways such as the tricarboxylic acid cycle, pyruvate metabolism and glycolysis/gluconeogenesis sharply fluctuated, while the ribosome protein complexes contributing to the translation process were generally elevated in chlortetracycline stress, which is known for a compensative tactic due to the action of chlortetracycline on the ribosome. Further antimicrobial susceptibility assays validated the role of differential proteins in metabolic pathways using genetically modified mutants of gene deletion of these differential proteins. Our study demonstrated that the down-regulation of metabolic pathways was a part of the global response and played an important role in the antibiotics resistance. These results indicate that reverting of these fluctuated pathways may become a novel strategy to combat antibiotic-resistant bacteria. PMID:24510206

Lin, Xiangmin; Kang, Liqun; Li, Hui; Peng, Xuanxian

2014-04-01

3

Multiple Pathways for All Students  

ERIC Educational Resources Information Center

Maine has been focusing on the importance of postsecondary training. Maine's Skowhegan Area High School (SAHS) and Somerset Career and Technical Center (SCTC) have partnered in a Multiple Pathways initiative (funded by the Nellie Mae Education Foundation) to increase students' high school completion rate and to increase enrollment in postsecondary…

Stirling, Lee Anna

2012-01-01

4

Multiple pathways regulate shoot branching  

PubMed Central

Shoot branching patterns result from the spatio-temporal regulation of axillary bud outgrowth. Numerous endogenous, developmental and environmental factors are integrated at the bud and plant levels to determine numbers of growing shoots. Multiple pathways that converge to common integrators are most probably involved. We propose several pathways involving not only the classical hormones auxin, cytokinins and strigolactones, but also other signals with a strong influence on shoot branching such as gibberellins, sugars or molecular actors of plant phase transition. We also deal with recent findings about the molecular mechanisms and the pathway involved in the response to shade as an example of an environmental signal controlling branching. We propose the TEOSINTE BRANCHED1, CYCLOIDEA, PCF transcription factor TB1/BRC1 and the polar auxin transport stream in the stem as possible integrators of these pathways. We finally discuss how modeling can help to represent this highly dynamic system by articulating knowledges and hypothesis and calculating the phenotype properties they imply.

Rameau, Catherine; Bertheloot, Jessica; Leduc, Nathalie; Andrieu, Bruno; Foucher, Fabrice; Sakr, Soulaiman

2015-01-01

5

Multiple pathways regulate shoot branching.  

PubMed

Shoot branching patterns result from the spatio-temporal regulation of axillary bud outgrowth. Numerous endogenous, developmental and environmental factors are integrated at the bud and plant levels to determine numbers of growing shoots. Multiple pathways that converge to common integrators are most probably involved. We propose several pathways involving not only the classical hormones auxin, cytokinins and strigolactones, but also other signals with a strong influence on shoot branching such as gibberellins, sugars or molecular actors of plant phase transition. We also deal with recent findings about the molecular mechanisms and the pathway involved in the response to shade as an example of an environmental signal controlling branching. We propose the TEOSINTE BRANCHED1, CYCLOIDEA, PCF transcription factor TB1/BRC1 and the polar auxin transport stream in the stem as possible integrators of these pathways. We finally discuss how modeling can help to represent this highly dynamic system by articulating knowledges and hypothesis and calculating the phenotype properties they imply. PMID:25628627

Rameau, Catherine; Bertheloot, Jessica; Leduc, Nathalie; Andrieu, Bruno; Foucher, Fabrice; Sakr, Soulaiman

2014-01-01

6

On the Time Required to Perform Multiplication  

Microsoft Academic Search

The time required to perform multiplication is investigated. A lower bound on the time required to perform multiplication, as well as multiplication modulo N, is derived and it is shown that these lower bounds can be approached. Then a lower bound on the amount of time required to perform the most significant part of multiplication (⌞xy\\/N⌟) is derived.

Shmuel Winograd; Yorktown Heights

1967-01-01

7

Demonstration of differential quantitative requirements for NSF among multiple vesicle fusion pathways of GLUT4 using a dominant-negative ATPase-deficient NSF  

SciTech Connect

In this study, we investigated the relative participation of N-ethylmaleimide-sensitive factor (NSF) in vivo in a complex multistep vesicle trafficking system, the translocation response of GLUT4 to insulin in rat adipose cells. Transfections of rat adipose cells demonstrate that over-expression of wild-type NSF has no effect on total, or basal and insulin-stimulated cell-surface expression of HA-tagged GLUT4. In contrast, a dominant-negative NSF (NSF-D1EQ) can be expressed at a low enough level that it has little effect on total HA-GLUT4, but does reduce both basal and insulin-stimulated cell-surface HA-GLUT4 by {approx}50% without affecting the GLUT4 fold-translocation response to insulin. However, high expression levels of NSF-D1EQ decrease total HA-GLUT4. The inhibitory effect of NSF-D1EQ on cell-surface HA-GLUT4 is reversed when endocytosis is inhibited by co-expression of a dominant-negative dynamin (dynamin-K44A). Moreover, NSF-D1EQ does not affect cell-surface levels of constitutively recycling GLUT1 and TfR, suggesting a predominant effect of low-level NSF-D1EQ on the trafficking of GLUT4 from the endocytic recycling compared to the intracellular GLUT4-specific compartment. Thus, our data demonstrate that the multiple fusion steps in GLUT4 trafficking have differential quantitative requirements for NSF activity. This indicates that the rates of plasma and intracellular membrane fusion reactions vary, leading to differential needs for the turnover of the SNARE proteins.

Chen Xiaoli [Experimental Diabetes, Metabolism, and Nutrition Section, Diabetes Branch, NIDDK, NIH, Bethesda, MD (United States); Matsumoto, Hideko [Experimental Diabetes, Metabolism, and Nutrition Section, Diabetes Branch, NIDDK, NIH, Bethesda, MD (United States); Hinck, Cynthia S. [Experimental Diabetes, Metabolism, and Nutrition Section, Diabetes Branch, NIDDK, NIH, Bethesda, MD (United States); Al-Hasani, Hadi [Institute of Biochemistry, University of Cologne, Cologne (Germany); St-Denis, Jean-Francois [Experimental Diabetes, Metabolism, and Nutrition Section, Diabetes Branch, NIDDK, NIH, Bethesda, MD (United States); Whiteheart, Sidney W. [Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY (United States); Cushman, Samuel W. [Experimental Diabetes, Metabolism, and Nutrition Section, Diabetes Branch, NIDDK, NIH, Bethesda, MD (United States)]. E-mail: sam_cushman@nih.gov

2005-07-22

8

Moral enhancement requires multiple virtues.  

PubMed

Some of the debates around the concept of moral enhancement have focused on whether the improvement of a single trait, such as empathy or intelligence, would be a good in general, or in all circumstances. All virtue theories, however, both secular and religious, have articulated multiple virtues that temper and inform one another in the development of a mature moral character. The project of moral enhancement requires a reengagement with virtue ethics and contemporary moral psychology to develop an empirically grounded model of the virtues and a fuller model of character development. Each of these virtues may be manipulable with electronic, psychopharmaceutical, and genetic interventions. A set of interdependent virtues is proposed, along with some of the research pointing to ways such virtues could be enhanced. PMID:25473861

Hughes, James J

2015-01-01

9

The TOR complex 1 is required for the interaction of multiple cargo proteins selected for the vacuole import and degradation pathway  

PubMed Central

Upon starving Saccharomyces cerevisiae of glucose, the key gluconeogenic enzymes fructose-1,6-bisphosphatase (FBPase), malate dehydrogenase (MDH2), isocitrate lyase (Icl1p) and phosphoenolpyruvate carboxykinase (Pck1p) are induced. When glucose is added to cells that have been starved for 3 days, these gluconeogenic enzymes are degraded in the vacuole via the vacuole import and degradation (Vid) pathway. Moreover, it has been determined that during glucose starvation, these cargo proteins interact with the target of rapamycin complex 1 (TORC1), which is comprised of Tor1p, Tco89p, Lst8p and Kog1p. However, following glucose replenishment, Tor1p dissociates from the cargo proteins. We have determined that cells overexpressing TOR1 inhibited the phosphorylation of FBPase and its subsequent degradation in the vacuole. Interestingly, while the deletion of TCO89 inhibited FBPase degradation, it did not inhibit the phosphorylation of FBPase. Both Tor1p and Tco89p were found in endosomes originating from the plasma membrane as well as in retrograde vesicles forming from the vacuole membrane. Here we further discuss our findings and elaborate on our current model of the Vid pathway. PMID:21331250

Alibhoy, Abbas A

2010-01-01

10

The TOR complex 1 is required for the interaction of multiple cargo proteins selected for the vacuole import and degradation pathway.  

PubMed

Upon starving Saccharomyces cerevisiae of glucose, the key gluconeogenic enzymes fructose-1,6-bisphosphatase (FBPase), malate dehydrogenase (MDH2), isocitrate lyase (Icl1p) and phosphoenolpyruvate carboxykinase (Pck1p) are induced. When glucose is added to cells that have been starved for 3 days, these gluconeogenic enzymes are degraded in the vacuole via the vacuole import and degradation (Vid) pathway. Moreover, it has been determined that during glucose starvation, these cargo proteins interact with the target of rapamycin complex 1 (TORC1), which is comprised of Tor1p, Tco89p, Lst8p and Kog1p. However, following glucose replenishment, Tor1p dissociates from the cargo proteins. We have determined that cells overexpressing TOR1 inhibited the phosphorylation of FBPase and its subsequent degradation in the vacuole. Interestingly, while the deletion of TCO89 inhibited FBPase degradation, it did not inhibit the phosphorylation of FBPase. Both Tor1p and Tco89p were found in endosomes originating from the plasma membrane as well as in retrograde vesicles forming from the vacuole membrane. Here we further discuss our findings and elaborate on our current model of the Vid pathway. PMID:21331250

Alibhoy, Abbas A; Chiang, Hui-Ling

2010-11-01

11

Ykt6p Is a Multifunctional Yeast R-SNARE That Is Required for Multiple Membrane Transport Pathways to the Vacuole  

Microsoft Academic Search

Intracellular membrane fusion requires that membrane-bound soluble N-ethylmaleimide-sensi- tive factor attachment protein receptor (SNARE) proteins on both vesicle and target membranes form a highly specific complex necessary to bring the membranes close in space. Ykt6p is a yeast R-SNARE protein that has been implicated in retrograde transport to the cis-Golgi compartment. Ykt6p has been also been found to fractionate with

Youngseok Kweon; Anca Rothe; Elizabeth Conibear; Tom H. Stevens

2003-01-01

12

Multiple ecological pathways to extinction in mammals  

PubMed Central

As human population and resource demands continue to grow, biodiversity conservation has never been more critical. About one-quarter of all mammals are in danger of extinction, and more than half of all mammal populations are in decline. A major priority for conservation science is to understand the ecological traits that predict extinction risk and the interactions among those predictors that make certain species more vulnerable than others. Here, using a new database of nearly 4,500 mammal species, we use decision-tree models to quantify the multiple interacting factors associated with extinction risk. We show that the correlates of extinction risk vary widely across mammals and that there are unique pathways to extinction for species with different lifestyles and combinations of traits. We find that risk is relative and that all kinds of mammals, across all body sizes, can be at risk depending on their specific ecologies. Our results increase the understanding of extinction processes, generate simple rules of thumb that identify species at greatest risk, and highlight the potential of decision-tree analyses to inform conservation efforts. PMID:19528635

Davidson, Ana D.; Hamilton, Marcus J.; Boyer, Alison G.; Brown, James H.; Ceballos, Gerardo

2009-01-01

13

Extreme-Longevity Mutations Orchestrate Silencing of Multiple Signaling Pathways  

PubMed Central

Long-lived mutants provide unique insights into the genetic factors that limit lifespan in wild-type animals. Most mutants and RNA-interference targets found to extend life, typically by 1.5- to 2.5-fold, were discovered in C. elegans. Several longevity-assurance pathways are conserved across widely divergent taxa, indicating that mechanisms of lifespan regulation evolved several hundred million years ago. Strong mutations to the C. elegans gene encoding AGE-1/PI3KCS achieve unprecedented longevity by orchestrating the modulation (predominantly silencing) of multiple signaling pathways. This is evident in a profound attenuation of total kinase activity, leading to reduced phosphoprotein content. Mutations to the gene encoding the catalytic subunit of PI3K (phosphatidylinositol 3-kinase) have the potential to modulate all enzymes that depend on its product, PIP3, for membrane tethering or activation by other kinases. Remarkably, strong mutants inactivating PI3K also silence multiple signaling pathways at the transcript level, partially but not entirely mediated by the DAF-16/FOXO transcription factor. Mammals have a relatively large proportion of somatic cells, and survival depends on their replication, whereas somatic cell divisions in nematodes are limited to development and reproductive tissues. Thus, translation of longevity gains from nematodes to mammals requires disentangling the downstream consequences of signaling mutations, to avoid their deleterious consequences. PMID:19465083

Shmookler Reis, Robert J.; Bharill, Puneet; Tazearslan, Cagdas; Ayyadevara, Srinivas

2009-01-01

14

Development of water requirement factors for biomass conversion pathway  

Microsoft Academic Search

Published data were used to develop an integrated spreadsheet-based model to estimate total water requirement for 12 biomass conversion pathways. The water requirement for crop production was attributed only to the grains in the estimates since agricultural residues are produced irrespective of their use for fuel or electricity. Corn stover- and wheat straw-based ethanol production pathways are water efficient, requiring

Shikhar Singh; Amit Kumar

2011-01-01

15

Multiple folding pathways for heterologously expressed human prion protein  

E-print Network

Multiple folding pathways for heterologously expressed human prion protein Graham S. Jackson , Anthony R. Clarke a , John Collinge aY * a Prion Disease Group, Department of Neurogenetics, Imperial-conformation in free solution. The data we present here shows that the human prion protein can exist in multiple

Hosszu, Laszlo

16

Multiple hydride reduction pathways in isoflavonoids  

PubMed Central

Background Isoflavonoids are of interest owing to their appearance in metabolic pathways of isoflavones, and their estrogenic and other physiological properties, making them promising lead compounds for drug design. Results The reduction of isoflavones by various hydride reagents occurs by a 1,4-pathway in contrast to ordinary ?-alkoxy-?,?-unsaturated ketones. Isoflavan-4-ones, cis- and trans-isoflavan-4-ols, ?-methyldeoxybenzoins or 1,2-diphenylprop-2-en-1-ols are obtained depending on the hydride reagent, mostly in good yields. The stereoselective reduction of isoflavan-4-ones is also discussed. Conclusion The work described in this paper shows that most structural types of reduced isoflavonoids are now reliably available in satisfactory or good yields by hydride reductions to be used as authentic reference compounds in analytical and biological studies. PMID:16934147

Salakka, Auli K; Jokela, Tuija H; Wähälä, Kristiina

2006-01-01

17

Costs of California Multiple Pathway Programs. Policy Report  

ERIC Educational Resources Information Center

There is widespread agreement that many of California's high schools are doing a poor job of preparing their students for college and careers. The James Irvine Foundation is sponsoring a major initiative to develop "Multiple Pathways"--now called the Linked Learning approach--as a strategy for improving the performance of California high schools.…

Parsi, Ace; Plank, David; Stern, David

2010-01-01

18

Drug-pathway interaction prediction via multiple feature fusion.  

PubMed

Predicting new drug-pathway interactions from heterogeneous biological data is important not only for the understanding of various drug response and molecular interaction processes, but also for the development of novel drugs and the therapy of human diseases. In this paper, three different learning methods including the Bipartite Local Models method (BLM), Gaussian Interaction Profiles kernels (GIP) method and Graph-based Semi-supervised Learning method (GBSSL) were used to predict drug-pathway interactions. To realize the purpose, drugs were firstly represented by functional groups and chemical structure similarity, and pathways were represented by their related gene expressions and semantic similarity based features. Then, the parameter optimization procedures were further adopted to deal with heterogeneous data sources. As a result, the proposed methods achieved a high ROC curve score (AUC score) over 0.95, which validated the effectiveness of multiple information integration. Moreover, several new potential drug-pathway interactions were identified for further biological function research. PMID:25122125

Song, Meiyue; Yan, Yan; Jiang, Zhenran

2014-11-01

19

Development of water requirement factors for biomass conversion pathway.  

PubMed

Published data were used to develop an integrated spreadsheet-based model to estimate total water requirement for 12 biomass conversion pathways. The water requirement for crop production was attributed only to the grains in the estimates since agricultural residues are produced irrespective of their use for fuel or electricity. Corn stover- and wheat straw-based ethanol production pathways are water efficient, requiring only 0.3 l, whereas biopower production pathways (i.e. direct combustion and bio-oil production) require about 0.8-0.9 l of water per MJ. Wheat- and corn-based ethanol production pathways consume 77 and 108 l of water per MJ, respectively. Utilization of switchgrass for production of ethanol, biopower through the direct combustion, and pyrolysis consume 128, 187 and 229 l of water per MJ, respectively. Biodiesel production from canola seed consumes 124 l of water per MJ. Corn stover- and wheat straw-based conversion pathways are most water efficient. PMID:20888758

Singh, Shikhar; Kumar, Amit

2011-01-01

20

Ubiquitin-protein ligases in muscle wasting: multiple parallel pathways?  

NASA Technical Reports Server (NTRS)

PURPOSE OF REVIEW: Studies in a wide variety of animal models of muscle wasting have led to the concept that increased protein breakdown via the ubiquitin-proteasome pathway is responsible for the loss of muscle mass seen as muscle atrophy. The complexity of the ubiquitination apparatus has hampered our understanding of how this pathway is activated in atrophying muscles and which ubiquitin-conjugating enzymes in muscle are responsible. RECENT FINDINGS: Recent experiments have shown that two newly identified ubiquitin-protein ligases (E3s), atrogin-1/MAFbx and MURF-1, are critical in the development of muscle atrophy. Other in-vitro studies also implicated E2(14k) and E3alpha, of the N-end rule pathway, as playing an important role in the process. SUMMARY: It seems likely that multiple pathways of ubiquitin conjugation are activated in parallel in atrophying muscle, perhaps to target for degradation specific classes of muscle proteins. The emerging challenge will be to define the protein targets for, as well as inhibitors of, these E3s.

Lecker, Stewart H.; Goldberg, A. L. (Principal Investigator)

2003-01-01

21

Multiple signal transduction pathways alterations during nerve agent toxicity.  

PubMed

Nerve agent toxicity is primarily due to the synaptic build up of toxic levels of acetylcholine. The acute lethal effects of the nerve agents are generally attributed to respiratory failure caused by a combination of effects at both central and peripheral levels and are further complicated by copious secretions, muscle fasciculations, and convulsions. In addition to this, a range of non cholinergic effects have been observed. The development of effective treatment to block multiple effects resulting from nerve agent exposure is hampered by a limited understanding of the molecular changes responsible for their persistent effects. Excessive accumulation of acetylcholine leads to activation nicotinic and muscarinic acetylcholine receptors, these receptors activate diverse kind of cellular responses by distinct signaling pathways. Metabolism of cyclic nucleotides, membrane phospholipids, activation of a multitude of protein kinases and the induction of transcription factors are the key biochemical steps and pathways that have been investigated. This review will focus on the effects of nerve agents on signal transduction pathways; particularly, MAP kinases, protein kinase C isozymes, calcium calmodulin dependent protein kinase II (CaMKII) and on cytoskeletal proteins, calpain, and certain transcription factors and discusses how such changes may be involved in nerve agent induced neurotoxicity. Alterations in these key brain proteins could explain the neurological impairments following nerve agent exposure. A better understanding of the whole picture may lead to new pharmacological interventions aimed to improve or modulate those signal transduction pathways affected during nerve agent poisoning or associated pathologies that are responsible for neuronal disturbances. PMID:22001750

RamaRao, G; Bhattacharya, B K

2012-01-01

22

Multiple pathways contribute to the pathogenesis of Huntington disease  

PubMed Central

Huntington disease (HD) is caused by expansion of a polyglutamine (polyQ) domain in the protein known as huntingtin (htt), and the disease is characterized by selective neurodegeneration. Expansion of the polyQ domain is not exclusive to HD, but occurs in eight other inherited neurodegenerative disorders that show distinct neuropathology. Yet in spite of the clear genetic defects and associated neurodegeneration seen with all the polyQ diseases, their pathogenesis remains elusive. The present review focuses on HD, outlining the effects of mutant htt in the nucleus and neuronal processes as well as the role of cell-cell interactions in HD pathology. The widespread expression and localization of mutant htt and its interactions with a variety of proteins suggest that mutant htt engages multiple pathogenic pathways. Understanding these pathways will help us to elucidate the pathogenesis of HD and to target therapies effectively. PMID:17173700

Li, Shihua; Li, Xiao-Jiang

2006-01-01

23

Inhibition of Myogenesis by Notch: Evidence for Multiple Pathways  

PubMed Central

Notch signaling is critical for skeletal muscle development and regeneration, permitting the expansion of progenitor cells by preventing premature differentiation. We have interrogated the pathways through which ligand-mediated signaling inhibits myogenesis by identifying Notch target genes and assessing their impact on differentiation in vitro. Notch activation led to the robust induction of the transcriptional repressors Hey1 and HeyL in myoblasts, but only constitutive expression of Hey1 blocked myogenesis. siRNA-mediated knockdown of Hey1 had no effect on Notch’s ability to inhibit differentiation, suggesting the existence of additional, possibly redundant pathways. We identified 82 genes whose expression was activated when C2C12 myoblasts were cultured in the presence of the Notch ligand Dll4. One of these, MyoR, is a novel Notch-responsive gene, whose protein product is known to repress myogenesis in vitro. siRNA-mediated knockdown of MyoR alone, or in combination with Hey1, was also ineffective at rescuing differentiation in the presence of Dll4. Our data support a model in which Notch signaling inhibits myogenesis through multiple pathways, two of which are defined by the Notch target genes Hey1 and MyoR. PMID:18727102

Buas, Matthew F.; Kabak, Shara; Kadesch, Tom

2014-01-01

24

Reovirus Uses Multiple Endocytic Pathways for Cell Entry  

PubMed Central

Entry of reovirus virions has been well studied in several tissue culture systems. After attachment to junctional adhesion molecule A (JAM-A), virions undergo clathrin-mediated endocytosis followed by proteolytic disassembly of the capsid and penetration to the cytoplasm. However, during in vivo infection of the intestinal tract, and likely in the tumor microenvironment, capsid proteolysis (uncoating) is initiated extracellularly. We used multiple approaches to determine if uncoated reovirus particles, called intermediate subviral particles (ISVPs), enter cells by directly penetrating the limiting membrane or if they take advantage of endocytic pathways to establish productive infection. We found that entry and infection by reovirus ISVPs was inhibited by dynasore, an inhibitor of dynamin-dependent endocytosis, as well as by genistein and dominant-negative caveolin-1, which block caveolar endocytosis. Inhibition of caveolar endocytosis also reduced infection by reovirus virions. Extraction of membrane cholesterol with methyl-?-cyclodextrin inhibited infection by virions but had no effect when infection was initiated with ISVPs. We found this pathway to be independent of both clathrin and caveolin. Together, these data suggest that reovirus virions can use both dynamin-dependent and dynamin-independent endocytic pathways during cell entry, and they reveal that reovirus ISVPs can take advantage of caveolar endocytosis to establish productive infection. PMID:22973022

Schulz, Wade L.; Haj, Amelia K.

2012-01-01

25

Multiple pathway asbestos exposure assessment for a Superfund community.  

PubMed

Libby, MT, USA, was the home to workers at a historical vermiculite mining facility and served as the processing and distribution center for this industrial product that was contaminated with amphibole asbestos. Several pathways of environmental asbestos exposure to the general population have been identified. The local clinic and health screening program collects data from participants on past occupational and environmental exposures to vermiculite and asbestos. Health studies among this population have demonstrated associations between amphibole exposure and health outcomes, but critical questions regarding the nature and level of exposure associated with specific outcomes remain unanswered. The objective of this study was to develop a comprehensive exposure assessment approach that integrates information on individuals' contact frequency with multiple exposure pathways. For 3031 participants, we describe cumulative exposure metrics for environmental exposures, occupational exposures, and residents' contact with carry-home asbestos from household workers. As expected, cumulative exposures for all three occupational categories were higher among men compared with women, and cumulative exposures for household contact and environmental pathways were higher among women. The comprehensive exposure assessment strategies will advance health studies and risk assessment approaches in this population with a complex history of both occupational and environmental asbestos exposure. PMID:24756101

Noonan, Curtis W; Conway, Kathrene; Landguth, Erin L; McNew, Tracy; Linker, Laura; Pfau, Jean; Black, Brad; Szeinuk, Jaime; Flores, Raja

2015-01-01

26

Multiple sweet receptors and transduction pathways revealed in knockout mice by temperature dependence and gurmarin sensitivity.  

PubMed

Sweet taste transduction involves taste receptor type 1, member 2 (T1R2), taste receptor type 1, member 3 (T1R3), gustducin, and TRPM5. Because knockout (KO) mice lacking T1R3, gustducin's Galpha subunit (Galphagust), or TRPM5 exhibited greatly reduced, but not abolished responses of the chorda tympani (CT) nerve to sweet compounds, it is likely that multiple sweet transduction pathways exist. That gurmarin (Gur), a sweet taste inhibitor, inhibits some but not all mouse CT responses to sweet compounds supports the existence of multiple sweet pathways. Here, we investigated Gur inhibition of CT responses to sweet compounds as a function of temperature in KO mice lacking T1R3, Galphagust, or TRPM5. In T1R3-KO mice, responses to sucrose and glucose were Gur sensitive (GS) and displayed a temperature-dependent increase (TDI). In Galphagust-KO mice, responses to sucrose and glucose were Gur-insensitive (GI) and showed a TDI. In TRPM5-KO mice, responses to glucose were GS and showed a TDI. All three KO mice exhibited no detectable responses to SC45647, and their responses to saccharin displayed neither GS nor a TDI. For all three KO mice, the lingual application of pronase, another sweet response inhibitor, almost fully abolished responses to sucrose and glucose but did not affect responses to saccharin. These results provide evidence for 1) the existence of multiple transduction pathways underlying responses to sugars: a T1R3-independent GS pathway for sucrose and glucose, and a TRPM5-independent temperature sensitive GS pathway for glucose; 2) the requirement for Galphagust in GS sweet taste responses; and 3) the existence of a sweet independent pathway for saccharin, in mouse taste cells on the anterior tongue. PMID:19211717

Ohkuri, Tadahiro; Yasumatsu, Keiko; Horio, Nao; Jyotaki, Masafumi; Margolskee, Robert F; Ninomiya, Yuzo

2009-04-01

27

Multiple pathways guide oxygen diffusion into flavoenzyme active sites  

PubMed Central

Dioxygen (O2) and other gas molecules have a fundamental role in a variety of enzymatic reactions. However, it is only poorly understood which O2 uptake mechanism enzymes employ to promote efficient catalysis and how general this is. We investigated O2 diffusion pathways into monooxygenase and oxidase flavoenzymes, using an integrated computational and experimental approach. Enhanced-statistics molecular dynamics simulations reveal spontaneous protein-guided O2 diffusion from the bulk solvent to preorganized protein cavities. The predicted protein-guided diffusion paths and the importance of key cavity residues for oxygen diffusion were verified by combining site-directed mutagenesis, rapid kinetics experiments, and high-resolution X-ray structures. This study indicates that monooxygenase and oxidase flavoenzymes employ multiple funnel-shaped diffusion pathways to absorb O2 from the solvent and direct it to the reacting C4a atom of the flavin cofactor. The difference in O2 reactivity among dehydrogenases, monooxygenases, and oxidases ultimately resides in the fine modulation of the local environment embedding the reactive locus of the flavin. PMID:19541622

Baron, Riccardo; Riley, Conor; Chenprakhon, Pirom; Thotsaporn, Kittisak; Winter, Remko T.; Alfieri, Andrea; Forneris, Federico; van Berkel, Willem J. H.; Chaiyen, Pimchai; Fraaije, Marco W.; Mattevi, Andrea; McCammon, J. Andrew

2009-01-01

28

Multiple pathways guide oxygen diffusion into flavoenzyme active sites.  

PubMed

Dioxygen (O(2)) and other gas molecules have a fundamental role in a variety of enzymatic reactions. However, it is only poorly understood which O(2) uptake mechanism enzymes employ to promote efficient catalysis and how general this is. We investigated O(2) diffusion pathways into monooxygenase and oxidase flavoenzymes, using an integrated computational and experimental approach. Enhanced-statistics molecular dynamics simulations reveal spontaneous protein-guided O(2) diffusion from the bulk solvent to preorganized protein cavities. The predicted protein-guided diffusion paths and the importance of key cavity residues for oxygen diffusion were verified by combining site-directed mutagenesis, rapid kinetics experiments, and high-resolution X-ray structures. This study indicates that monooxygenase and oxidase flavoenzymes employ multiple funnel-shaped diffusion pathways to absorb O(2) from the solvent and direct it to the reacting C4a atom of the flavin cofactor. The difference in O(2) reactivity among dehydrogenases, monooxygenases, and oxidases ultimately resides in the fine modulation of the local environment embedding the reactive locus of the flavin. PMID:19541622

Baron, Riccardo; Riley, Conor; Chenprakhon, Pirom; Thotsaporn, Kittisak; Winter, Remko T; Alfieri, Andrea; Forneris, Federico; van Berkel, Willem J H; Chaiyen, Pimchai; Fraaije, Marco W; Mattevi, Andrea; McCammon, J Andrew

2009-06-30

29

Induction of Cytoprotective Pathways Is Central to the Extension of Lifespan Conferred by Multiple Longevity Pathways  

PubMed Central

Many genetic and physiological treatments that extend lifespan also confer resistance to a variety of stressors, suggesting that cytoprotective mechanisms underpin the regulation of longevity. It has not been established, however, whether the induction of cytoprotective pathways is essential for lifespan extension or merely correlated. Using a panel of GFP-fused stress response genes, we identified the suites of cytoprotective pathways upregulated by 160 gene inactivations known to increase Caenorhabditis elegans longevity, including the mitochondrial UPR (hsp-6, hsp-60), the ER UPR (hsp-4), ROS response (sod-3, gst-4), and xenobiotic detoxification (gst-4). We then screened for other gene inactivations that disrupt the induction of these responses by xenobiotic or genetic triggers, identifying 29 gene inactivations required for cytoprotective gene expression. If cytoprotective responses contribute directly to lifespan extension, inactivation of these genes would be expected to compromise the extension of lifespan conferred by decreased insulin/IGF-1 signaling, caloric restriction, or the inhibition of mitochondrial function. We find that inactivation of 25 of 29 cytoprotection-regulatory genes shortens the extension of longevity normally induced by decreased insulin/IGF-1 signaling, disruption of mitochondrial function, or caloric restriction, without disrupting normal longevity nearly as dramatically. These data demonstrate that induction of cytoprotective pathways is central to longevity extension and identify a large set of new genetic components of the pathways that detect cellular damage and couple that detection to downstream cytoprotective effectors. PMID:22829775

Shore, David E.; Carr, Christopher E.; Ruvkun, Gary

2012-01-01

30

Estrogen Signaling Multiple Pathways to Impact Gene Transcription  

PubMed Central

Steroid hormones exert profound effects on cell growth, development, differentiation, and homeostasis. Their effects are mediated through specific intracellular steroid receptors that act via multiple mechanisms. Among others, the action mechanism starting upon 17?-estradiol (E2) binds to its receptors (ER) is considered a paradigmatic example of how steroid hormones function. Ligand-activated ER dimerizes and translocates in the nucleus where it recognizes specific hormone response elements located in or near promoter DNA regions of target genes. Behind the classical genomic mechanism shared with other steroid hormones, E2 also modulates gene expression by a second indirect mechanism that involves the interaction of ER with other transcription factors which, in turn, bind their cognate DNA elements. In this case, ER modulates the activities of transcription factors such as the activator protein (AP)-1, nuclear factor-?B (NF-?B) and stimulating protein-1 (Sp-1), by stabilizing DNA-protein complexes and/or recruiting co-activators. In addition, E2 binding to ER may also exert rapid actions that start with the activation of a variety of signal transduction pathways (e.g. ERK/MAPK, p38/MAPK, PI3K/AKT, PLC/PKC). The debate about the contribution of different ER-mediated signaling pathways to coordinate the expression of specific sets of genes is still open. This review will focus on the recent knowledge about the mechanism by which ERs regulate the expression of target genes and the emerging field of integration of membrane and nuclear receptor signaling, giving examples of the ways by which the genomic and non-genomic actions of ERs on target genes converge. PMID:18369406

Marino, Maria; Galluzzo, Paola; Ascenzi, Paolo

2006-01-01

31

Timing the multiple cell death pathways initiated by Rose Bengal acetate photodynamic therapy  

Microsoft Academic Search

Rose Bengal acetate photodynamic therapy (RBAc–PDT) induced multiple cell death pathways in HeLa cells through ROS and ER stress. Indeed, apoptosis was the first preferred mechanism of death, and it was triggered by at least four different pathways, whose independent temporal activation ensures cell killing when one or several of the pathways are inactivated. Apoptosis occurred as early as 1

E Panzarini; V Inguscio; L Dini

2011-01-01

32

Requirements for a conservative protein translocation pathway in chloroplasts.  

PubMed

The chloroplast inner envelope translocon subunit Tic110 is imported via a soluble stromal translocation intermediate. In this study an in-organellar import system is established which allows for an accumulation of this intermediate in order to analyze its requirements for reexport. All results demonstrate that the re-export of Tic110 from the soluble intermediate stage into the inner envelope requires ATP hydrolysis, which cannot be replaced by other NTPs. Furthermore, the molecular chaperone Hsp93 seems prominently involved in the reexport pathway of Tic110, because other stromal intermediates like that of the oxygen evolving complex subunit OE33 (iOE33) en route to the thylakoid lumen interacts preferentially with Hsp70. PMID:17507010

Vojta, Lea; Soll, Jürgen; Bölter, Bettina

2007-06-12

33

Inferring signaling pathway topologies from multiple perturbation measurements of specific biochemical species.  

PubMed

The specification of biological decisions by signaling pathways is encoded by the interplay between activation dynamics and network topologies. Although we can describe complex networks, we cannot easily determine which topology the cell actually uses to transduce a specific signal. Experimental testing of all plausible topologies is infeasible because of the combinatorially large number of experiments required to explore the complete hypothesis space. Here, we demonstrate that Bayesian inference-based modeling provides an approach to explore and constrain this hypothesis space,permitting the rational ranking of pathway models. Our approach can use measurements of a limited number of biochemical species when combined with multiple perturbations. As proof of concept, we examined the activation of the extracellular signal-regulated kinase (ERK) pathway by epidermal growth factor. The predicted and experimentally validated model shows that both Raf-1 and, unexpectedly,B-Raf are needed to fully activate ERK in two different cell lines. Thus, our formal methodology rationally infers evidentially supported pathway topologies even when a limited number of biochemical and kinetic measurements are available. PMID:20731071

Xu, Tian-Rui; Vyshemirsky, Vladislav; Gormand, Amélie; von Kriegsheim, Alex; Girolami, Mark; Baillie, George S; Ketley, Dominic; Dunlop, Allan J; Milligan, Graeme; Houslay, Miles D; Kolch, Walter

2010-01-01

34

Inferring signaling pathway topologies from multiple perturbation measurements of specific biochemical species.  

PubMed

The specification of biological decisions by signaling pathways is encoded by the interplay between activation dynamics and network topologies. Although we can describe complex networks, we cannot easily determine which topology the cell actually uses to transduce a specific signal. Experimental testing of all plausible topologies is infeasible because of the combinatorially large number of experiments required to explore the complete hypothesis space. Here, we demonstrate that Bayesian inference-based modeling provides an approach to explore and constrain this hypothesis space, permitting the rational ranking of pathway models. Our approach can use measurements of a limited number of biochemical species when combined with multiple perturbations. As proof of concept, we examined the activation of the extracellular signal-regulated kinase (ERK) pathway by epidermal growth factor. The predicted and experimentally validated model shows that both Raf-1 and, unexpectedly, B-Raf are needed to fully activate ERK in two different cell lines. Thus, our formal methodology rationally infers evidentially supported pathway topologies even when a limited number of biochemical and kinetic measurements are available. PMID:20234003

Xu, Tian-Rui; Vyshemirsky, Vladislav; Gormand, Amélie; von Kriegsheim, Alex; Girolami, Mark; Baillie, George S; Ketley, Dominic; Dunlop, Allan J; Milligan, Graeme; Houslay, Miles D; Kolch, Walter

2010-01-01

35

Regulation of Multiple Carbon Monoxide Consumption Pathways in Anaerobic Bacteria  

PubMed Central

Carbon monoxide (CO), well known as a toxic gas, is increasingly recognized as a key metabolite and signaling molecule. Microbial utilization of CO is quite common, evidenced by the rapid escalation in description of new species of CO-utilizing bacteria and archaea. Carbon monoxide dehydrogenase (CODH), the protein complex that enables anaerobic CO-utilization, has been well-characterized from an increasing number of microorganisms, however the regulation of multiple CO-related gene clusters in single isolates remains unexplored. Many species are extraordinarily resistant to high CO concentrations, thriving under pure CO at more than one atmosphere. We hypothesized that, in strains that can grow exclusively on CO, both carbon acquisition via the CODH/acetyl CoA synthase complex and energy conservation via a CODH-linked hydrogenase must be differentially regulated in response to the availability of CO. The CO-sensing transcriptional activator, CooA is present in most CO-oxidizing bacteria. Here we present a genomic and phylogenetic survey of CODH operons and cooA genes found in CooA-containing bacteria. Two distinct groups of CooA homologs were found: one clade (CooA-1) is found in the majority of CooA-containing bacteria, whereas the other clade (CooA-2) is found only in genomes that encode multiple CODH clusters, suggesting that the CooA-2 might be important for cross-regulation of competing CODH operons. Recombinant CooA-1 and CooA-2 regulators from the prototypical CO-utilizing bacterium Carboxydothermus hydrogenoformans were purified, and promoter binding analyses revealed that CooA-1 specifically regulates the hydrogenase-linked CODH, whereas CooA-2 is able to regulate both the hydrogenase-linked CODH and the CODH/ACS operons. These studies point to the ability of dual CooA homologs to partition CO into divergent CO-utilizing pathways resulting in efficient consumption of a single limiting growth substrate available across a wide range of concentrations. PMID:21808633

Techtmann, Stephen M.; Colman, Albert S.; Murphy, Michael B.; Schackwitz, Wendy S.; Goodwin, Lynne A.; Robb, Frank T.

2011-01-01

36

Sustaining multiple ecosystem functions in grassland communities requires higher biodiversity  

E-print Network

Sustaining multiple ecosystem functions in grassland communities requires higher biodiversity Erika (sent for review July 27, 2009) Society places value on the multiple functions of ecosystems from ecosystems to provide threshold levels of up to eight ecosystem functions simultaneously. Across years

Zavaleta, Erika

37

Why do personality traits predict divorce? Multiple pathways through satisfaction.  

PubMed

While previous studies indicate that personality traits influence the likelihood of divorce, the processes that drive this relationship have yet to be examined. Accordingly, the current study utilized a nationally representative, longitudinal sample (N = 8,206) to test whether relationship satisfaction is a pathway by which personality traits influence relationship dissolution. Specifically, we examined 2 different pathways: the enduring dynamics and emergent distress pathways. The enduring dynamics pathway specifies that the association between personality and relationship satisfaction reflects ongoing relationship dynamics, which are presumed to be stable across a relationship. In contrast, the emergent distress pathway proposes that personality leads to worsening dynamics across the course of a relationship, which is indicated by changes in satisfaction. For each pathway, we assessed actor, partner, and combined effects for the Big Five. Results replicate previous research in that personality traits prospectively predict relationship dissolution. Both the enduring dynamics and emergent distress pathways served to explain this relationship, though the enduring dynamics model evidenced the largest effects. The emergent distress pathway was stronger for couples who experienced certain life events, suggesting that personality plays a role in adapting to changing life circumstances. Moreover, results suggest that the personality of the dyad is important in this process: Above and beyond actor effects, partner effects influenced relationship functioning (although the influence of combined effects was less clear). In sum, the current study demonstrates that personality traits shape the overall quality of one's relationship, which in turn influences the likelihood of relationship dissolution. PMID:24841100

Solomon, Brittany C; Jackson, Joshua J

2014-06-01

38

Transition model for ricin-aptamer interactions with multiple pathways and energy barriers.  

PubMed

We develop a transition model to interpret single-molecule ricin-aptamer interactions with multiple unbinding pathways and energy barriers measured by atomic force microscopy dynamic force spectroscopy. Molecular simulations establish the relationship between binding conformations and the corresponding unbinding pathways. Each unbinding pathway follows a Bell-Evans multiple-barrier model. Markov-type transition matrices are developed to analyze the redistribution of unbinding events among the pathways under different loading rates. Our study provides detailed information about complex behaviors in ricin-aptamer unbinding events. PMID:25353521

Wang, Bin; Xu, Bingqian

2014-02-01

39

Transition model for ricin-aptamer interactions with multiple pathways and energy barriers  

NASA Astrophysics Data System (ADS)

We develop a transition model to interpret single-molecule ricin-aptamer interactions with multiple unbinding pathways and energy barriers measured by atomic force microscopy dynamic force spectroscopy. Molecular simulations establish the relationship between binding conformations and the corresponding unbinding pathways. Each unbinding pathway follows a Bell-Evans multiple-barrier model. Markov-type transition matrices are developed to analyze the redistribution of unbinding events among the pathways under different loading rates. Our study provides detailed information about complex behaviors in ricin-aptamer unbinding events.

Wang, Bin; Xu, Bingqian

2014-02-01

40

MicroRNA-17?92 plays a causative role in lymphomagenesis by coordinating multiple oncogenic pathways  

PubMed Central

MicroRNAs (miRNAs) have been broadly implicated in cancer, but their exact function and mechanism in carcinogenesis remain poorly understood. Elevated miR-17?92 expression is frequently found in human cancers, mainly due to gene amplification and Myc-mediated transcriptional upregulation. Here we show that B cell-specific miR-17?92 transgenic mice developed lymphomas with high penetrance and that, conversely, Myc-driven lymphomagenesis stringently requires two intact alleles of miR-17?92. We experimentally identified miR-17?92 target genes by PAR-CLIP and validated select target genes in miR-17?92 transgenic mice. These analyses demonstrate that miR-17?92 drives lymphomagenesis by suppressing the expression of multiple negative regulators of the PI3K and NF?B pathways and by inhibiting the mitochondrial apoptosis pathway. Accordingly, miR-17?92-driven lymphoma cells exhibited constitutive activation of the PI3K and NF?B pathways and chemical inhibition of either pathway reduced tumour size and prolonged the survival of lymphoma-bearing mice. These findings establish miR-17?92 as a powerful cancer driver that coordinates the activation of multiple oncogenic pathways, and demonstrate for the first time that chemical inhibition of miRNA downstream pathways has therapeutic value in treating cancers caused by miRNA dysregulation. PMID:23921550

Jin, Hyun Yong; Oda, Hiroyo; Lai, Maoyi; Skalsky, Rebecca L; Bethel, Kelly; Shepherd, Jovan; Kang, Seung Goo; Liu, Wen-Hsien; Sabouri-Ghomi, Mohsen; Cullen, Bryan R; Rajewsky, Klaus; Xiao, Changchun

2013-01-01

41

Multiple Transmission Pathways and Disease Dynamics in a Waterborne Pathogen Model  

Microsoft Academic Search

Multiple transmission pathways exist for many waterborne diseases, including cholera, Giardia, Cryptosporidium, and Campylobacter. Theoretical work exploring the effects of multiple transmission pathways on disease dynamics is incomplete. Here, we consider\\u000a a simple ODE model that extends the classical SIR framework by adding a compartment (W) that tracks pathogen concentration in the water. Infected individuals shed pathogen into the water compartment,

Joseph H. Tien; David J. D. Earn

2010-01-01

42

Reliable pre-eclampsia pathways based on multiple independent microarray data sets.  

PubMed

Pre-eclampsia is a multifactorial disorder characterized by heterogeneous clinical manifestations. Gene expression profiling of preeclamptic placenta have provided different and even opposite results, partly due to data compromised by various experimental artefacts. Here we aimed to identify reliable pre-eclampsia-specific pathways using multiple independent microarray data sets. Gene expression data of control and preeclamptic placentas were obtained from Gene Expression Omnibus. Single-sample gene-set enrichment analysis was performed to generate gene-set activation scores of 9707 pathways obtained from the Molecular Signatures Database. Candidate pathways were identified by t-test-based screening using data sets, GSE10588, GSE14722 and GSE25906. Additionally, recursive feature elimination was applied to arrive at a further reduced set of pathways. To assess the validity of the pre-eclampsia pathways, a statistically-validated protocol was executed using five data sets including two independent other validation data sets, GSE30186, GSE44711. Quantitative real-time PCR was performed for genes in a panel of potential pre-eclampsia pathways using placentas of 20 women with normal or severe preeclamptic singleton pregnancies (n = 10, respectively). A panel of ten pathways were found to discriminate women with pre-eclampsia from controls with high accuracy. Among these were pathways not previously associated with pre-eclampsia, such as the GABA receptor pathway, as well as pathways that have already been linked to pre-eclampsia, such as the glutathione and CDKN1C pathways. mRNA expression of GABRA3 (GABA receptor pathway), GCLC and GCLM (glutathione metabolic pathway), and CDKN1C was significantly reduced in the preeclamptic placentas. In conclusion, ten accurate and reliable pre-eclampsia pathways were identified based on multiple independent microarray data sets. A pathway-based classification may be a worthwhile approach to elucidate the pathogenesis of pre-eclampsia. PMID:25323968

Kawasaki, Kaoru; Kondoh, Eiji; Chigusa, Yoshitsugu; Ujita, Mari; Murakami, Ryusuke; Mogami, Haruta; Brown, J B; Okuno, Yasushi; Konishi, Ikuo

2015-02-01

43

Studies of the lamin proteinase reveal multiple parallel biochemical pathways during apoptotic execution.  

PubMed Central

Although specific proteinases play a critical role in the active phase of apoptosis, their substrates are largely unknown. We previously identified poly(ADP-ribose) polymerase (PARP) as an apoptosis-associated substrate for proteinase(s) related to interleukin 1 beta-converting enzyme (ICE). Now we have used a cell-free system to characterize proteinase(s) that cleave the nuclear lamins during apoptosis. Lamin cleavage during apoptosis requires the action of a second ICE-like enyzme, which exhibits kinetics of cleavage and a profile of sensitivity to specific inhibitors that is distinct from the PARP proteinase. Thus, multiple ICE-like enzymes are required for apoptotic events in these cell-free extracts. Inhibition of the lamin proteinase with tosyllysine "chloromethyl ketone" blocks nuclear apoptosis prior to the packaging of condensed chromatin into apoptotic bodies. Under these conditions, the nuclear DNA is fully cleaved to a nucleosomal ladder. Our studies reveal that the lamin proteinase and the fragmentation nuclease function in independent parallel pathways during the final stages of apoptotic execution. Neither pathway alone is sufficient for completion of nuclear apoptosis. Instead, the various activities cooperate to drive the disassembly of the nucleus. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:7568069

Lazebnik, Y A; Takahashi, A; Moir, R D; Goldman, R D; Poirier, G G; Kaufmann, S H; Earnshaw, W C

1995-01-01

44

Induction of Cytoprotective Pathways Is Central to the Extension of Lifespan Conferred by Multiple Longevity Pathways  

Microsoft Academic Search

Many genetic and physiological treatments that extend lifespan also confer resistance to a variety of stressors, suggesting that cytoprotective mechanisms underpin the regulation of longevity. It has not been established, however, whether the induction of cytoprotective pathways is essential for lifespan extension or merely correlated. Using a panel of GFP-fused stress response genes, we identified the suites of cytoprotective pathways

David E. Shore; Christopher E. Carr; Gary Ruvkun

2012-01-01

45

Hedgehog Pathway Modulation by Multiple Lipid Binding Sites on the Smoothened Effector of Signal Response  

PubMed Central

Summary Hedgehog (Hh) signaling during development and in postembryonic tissues requires activation of the 7TM oncoprotein Smoothened (Smo), by mechanisms that may involve endogenous lipidic modulators. Exogenous Smo ligands previously identified include the plant sterol cyclopamine (and its therapeutically useful synthetic mimics) and hydroxylated cholesterol derivatives (oxysterols); Smo is also highly sensitive to cellular sterol levels. The relationships between these effects are unclear because the relevant Smo structural determinants are unknown. We identify the conserved extracellular cysteine rich domain (CRD) as the site of action for oxysterols on Smo, involving residues structurally analogous to those contacting the Wnt lipid adduct in the homologous Frizzled CRD; this modulatory effect is distinct from that of cyclopamine mimics, from Hh-mediated regulation, and from the permissive action of cellular sterol pools. These results imply that Hh pathway activity is sensitive to lipid binding at several Smo sites, suggesting mechanisms for tuning by multiple physiological inputs. PMID:23954590

Myers, Benjamin R.; Sever, Navdar; Chong, Yong Chun; Kim, James; Belani, Jitendra D.; Rychnovsky, Scott; Bazan, J. Fernando; Beachy, Philip A.

2014-01-01

46

Piceatannol exhibits selective toxicity to multiple myeloma cells and influences the Wnt/ beta-catenin pathway.  

PubMed

Aberrant activation of Wnt/?-catenin signaling promotes development and progression of various malignant neoplasms. Recent studies observed that the Wnt pathway is constitutively active in myeloma cells and promotes an exaggerated proliferation. Thus, the Wnt signaling pathway might be an attractive therapeutic target for multiple myeloma. In this study, we identified piceatannol as an inhibitor of the Wnt/?-catenin pathway and as a potent inducer of apoptosis in myeloma cells. Interestingly, healthy cells remained mainly unaffected. These results reveal a significant selective induction of apoptosis by piceatannol and suggest a significant in vivo effect against multiple myeloma. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24470348

Schmeel, Frederic Carsten; Schmeel, Leonard Christopher; Kim, Young; Schmidt-Wolf, Ingo G H

2014-12-01

47

Bayesian joint selection of genes and pathways: applications in multiple myeloma genomics.  

PubMed

It is well-established that the development of a disease, especially cancer, is a complex process that results from the joint effects of multiple genes involved in various molecular signaling pathways. In this article, we propose methods to discover genes and molecular pathways significantly associated with clinical outcomes in cancer samples. We exploit the natural hierarchal structure of genes related to a given pathway as a group of interacting genes to conduct selection of both pathways and genes. We posit the problem in a hierarchical structured variable selection (HSVS) framework to analyze the corresponding gene expression data. HSVS methods conduct simultaneous variable selection at the pathway (group level) and the gene (within-group) level. To adapt to the overlapping group structure present in the pathway-gene hierarchy of the data, we developed an overlap-HSVS method that introduces latent partial effect variables that partition the marginal effect of the covariates and corresponding weights for a proportional shrinkage of the partial effects. Combining gene expression data with prior pathway information from the KEGG databases, we identified several gene-pathway combinations that are significantly associated with clinical outcomes of multiple myeloma. Biological discoveries support this relationship for the pathways and the corresponding genes we identified. PMID:25520554

Zhang, Lin; Morris, Jeffrey S; Zhang, Jiexin; Orlowski, Robert Z; Baladandayuthapani, Veerabhadran

2014-01-01

48

Canonical and noncanonical Hedgehog pathway in the pathogenesis of multiple myeloma  

PubMed Central

The Hedgehog (Hh) pathway is required for cell-fate determination during the embryonic life, as well as cell growth and differentiation in the adult organism, where the inappropriate activation has been implicated in several cancers. Here we demonstrate that Hh signaling plays a significant role in growth and survival of multiple myeloma (MM) cells. We observed that CD138+ MM cells express Hh genes and confirmed Smoothened (Smo)–dependent Hh signaling in MM using a novel synthetic Smo inhibitor, NVP-LDE225 (Novartis), which decreased MM cell viability by inducing specific down-regulation of Gli1 and Ptch1, hallmarks of Hh activity. In addition, we detected a nuclear localization of Gli1 in MM cells, which is completely abrogated by Forskolin, a Gli1-modulating compound, confirming Smo-independent mechanisms leading to Hh activation in MM. Finally, we identified that bone marrow stromal cells are a source of the Shh ligand, although they are resistant to the Hh inhibitor because of defective Smo expression and Ptch1 up-regulation. Further in vitro as well as in vivo studies showed antitumor efficacy of NVP-LDE225 in combination with bortezomib. Altogether, our data demonstrate activation of both canonical and noncanonical Hh pathway in MM, thus providing the rationale for testing Hh inhibitors in clinical trials to improve MM patient outcome. PMID:22821765

Blotta, Simona; Jakubikova, Jana; Calimeri, Teresa; Roccaro, Aldo M.; Amodio, Nicola; Azab, Abdel Kareem; Foresta, Umberto; Mitsiades, Constantine S.; Rossi, Marco; Todoerti, Katia; Molica, Stefano; Morabito, Fortunato; Neri, Antonino; Tagliaferri, Piersandro; Tassone, Pierfrancesco; Anderson, Kenneth C.

2012-01-01

49

Multiple internalization pathways of polyelectrolyte multilayer capsules into mammalian cells.  

PubMed

Polyelectrolyte multilayer (PEM) capsules are carrier vehicles with great potential for biomedical applications. With the future aim of designing biocompatible, effective therapeutic delivery systems (e.g., for cancer), the pathway of internalization (uptake and fate) of PEM capsules was investigated. In particular the following experiments were performed: (i) the study of capsule co-localization with established endocytic markers, (ii) switching-off endocytotic pathways with pharmaceutical/chemical inhibitors, and (iii) characterization and quantification of capsule uptake with confocal and electron microscopy. As result, capsules co-localized with lipid rafts and with phagolysosomes, but not with other endocytic vesicles. Chemical interference of endocytosis with chemical blockers indicated that PEM capsules enter the investigated cell lines through a mechanism slightly sensitive to electrostatic interactions, independent of clathrin and caveolae, and strongly dependent on cholesterol-rich domains and organelle acidification. Microscopic characterization of cells during capsule uptake showed the formation of phagocytic cups (vesicles) to engulf the capsules, an increased number of mitochondria, and a final localization in the perinuclear cytoplasma. Combining all these indicators we conclude that PEM capsule internalization in general occurs as a combination of different sequential mechanisms. Initially, an adsorptive mechanism due to strong electrostatic interactions governs the stabilization of the capsules at the cell surface. Membrane ruffling and filopodia extensions are responsible for capsule engulfing through the formation of a phagocytic cup. Co-localization with lipid raft domains activates the cell to initiate a lipid-raft-mediated macropinocytosis. Internalization vesicles are very acidic and co-localize only with phagolysosome markers, excluding caveolin-mediated pathways and indicating that upon phagocytosis the capsules are sorted to heterophagolysosomes. PMID:23826767

Kastl, Lena; Sasse, Daniel; Wulf, Verena; Hartmann, Raimo; Mircheski, Josif; Ranke, Christiane; Carregal-Romero, Susana; Martínez-López, José Antonio; Fernández-Chacón, Rafael; Parak, Wolfgang J; Elsasser, Hans-Peter; Rivera Gil, Pilar

2013-08-27

50

Screening Reactive Metabolites Bioactivated by Multiple Enzyme Pathways Using a Multiplexed Microfluidic System  

PubMed Central

A multiplexed, microfluidic platform to detect reactive metabolites is described, and its performance is illustrated for compounds metabolized by oxidative and bioconjugation enzymes in multi-enzyme pathways to mimic natural human drug metabolism. The device features four 8-electrode screen printed carbon arrays coated with thin films of DNA, a ruthenium-polyvinylpyridine (RuPVP) catalyst, and multiple enzyme sources including human liver microsomes (HLM), cytochrome P450 (cyt P450) 1B1 supersomes, microsomal epoxide hydrolase (EH), human S9 liver fractions (Hs9) and N-acetyltransferase (NAT). Arrays are arranged in parallel to facilitate multiple compound screening, enabling up to 32 enzyme reactions and measurements in 20–30 min. In the first step of the assay, metabolic reactions are achieved under constant flow of oxygenated reactant solutions by electrode driven natural catalytic cycles of cyt P450s and cofactor-supported bioconjugation enzymes. Reactive metabolites formed in the enzyme reactions can react with DNA. Relative DNA damage is measuring in the second assay step using square wave voltammetry (SWV) with RuPVP as catalyst. Studies were done on chemicals known to require metabolic activation to induce genotoxicity, and results reproduced known features of metabolite DNA-reactivity for the test compounds. Metabolism of benzo[a]pyrene (B[a]P) by cyt P450s and epoxide hydrolase showed an enhanced relative DNA damage rate for DNA damage compared to cyt P450s alone. DNA damage rates for arylamines by pathways featuring both oxidative and conjugative enzymes at pH 7.4 gave better correlation with rodent genotoxicity metric TD50. Results illustrate the broad utility of the reactive metabolite screening device. PMID:23095952

Wasalathanthri, Dhanuka P.; Faria, Ronaldo C.; Malla, Spundana; Joshi, Amit A.; Schenkman, John B.; Rusling, James F.

2012-01-01

51

Cytolethal Distending Toxins Require Components of the ER-Associated Degradation Pathway for Host Cell Entry  

PubMed Central

Intracellular acting protein exotoxins produced by bacteria and plants are important molecular determinants that drive numerous human diseases. A subset of these toxins, the cytolethal distending toxins (CDTs), are encoded by several Gram-negative pathogens and have been proposed to enhance virulence by allowing evasion of the immune system. CDTs are trafficked in a retrograde manner from the cell surface through the Golgi apparatus and into the endoplasmic reticulum (ER) before ultimately reaching the host cell nucleus. However, the mechanism by which CDTs exit the ER is not known. Here we show that three central components of the host ER associated degradation (ERAD) machinery, Derlin-2 (Derl2), the E3 ubiquitin-protein ligase Hrd1, and the AAA ATPase p97, are required for intoxication by some CDTs. Complementation of Derl2-deficient cells with Derl2:Derl1 chimeras identified two previously uncharacterized functional domains in Derl2, the N-terminal 88 amino acids and the second ER-luminal loop, as required for intoxication by the CDT encoded by Haemophilus ducreyi (Hd-CDT). In contrast, two motifs required for Derlin-dependent retrotranslocation of ERAD substrates, a conserved WR motif and an SHP box that mediates interaction with the AAA ATPase p97, were found to be dispensable for Hd-CDT intoxication. Interestingly, this previously undescribed mechanism is shared with the plant toxin ricin. These data reveal a requirement for multiple components of the ERAD pathway for CDT intoxication and provide insight into a Derl2-dependent pathway exploited by retrograde trafficking toxins. PMID:25078082

Eshraghi, Aria; Dixon, Shandee D.; Tamilselvam, Batcha; Kim, Emily Jin-Kyung; Gargi, Amandeep; Kulik, Julia C.; Damoiseaux, Robert; Blanke, Steven R.; Bradley, Kenneth A.

2014-01-01

52

Cytolethal distending toxins require components of the ER-associated degradation pathway for host cell entry.  

PubMed

Intracellular acting protein exotoxins produced by bacteria and plants are important molecular determinants that drive numerous human diseases. A subset of these toxins, the cytolethal distending toxins (CDTs), are encoded by several Gram-negative pathogens and have been proposed to enhance virulence by allowing evasion of the immune system. CDTs are trafficked in a retrograde manner from the cell surface through the Golgi apparatus and into the endoplasmic reticulum (ER) before ultimately reaching the host cell nucleus. However, the mechanism by which CDTs exit the ER is not known. Here we show that three central components of the host ER associated degradation (ERAD) machinery, Derlin-2 (Derl2), the E3 ubiquitin-protein ligase Hrd1, and the AAA ATPase p97, are required for intoxication by some CDTs. Complementation of Derl2-deficient cells with Derl2:Derl1 chimeras identified two previously uncharacterized functional domains in Derl2, the N-terminal 88 amino acids and the second ER-luminal loop, as required for intoxication by the CDT encoded by Haemophilus ducreyi (Hd-CDT). In contrast, two motifs required for Derlin-dependent retrotranslocation of ERAD substrates, a conserved WR motif and an SHP box that mediates interaction with the AAA ATPase p97, were found to be dispensable for Hd-CDT intoxication. Interestingly, this previously undescribed mechanism is shared with the plant toxin ricin. These data reveal a requirement for multiple components of the ERAD pathway for CDT intoxication and provide insight into a Derl2-dependent pathway exploited by retrograde trafficking toxins. PMID:25078082

Eshraghi, Aria; Dixon, Shandee D; Tamilselvam, Batcha; Kim, Emily Jin-Kyung; Gargi, Amandeep; Kulik, Julia C; Damoiseaux, Robert; Blanke, Steven R; Bradley, Kenneth A

2014-07-01

53

Network-based identification of biomarkers coexpressed with multiple pathways.  

PubMed

Unraveling complex molecular interactions and networks and incorporating clinical information in modeling will present a paradigm shift in molecular medicine. Embedding biological relevance via modeling molecular networks and pathways has become increasingly important for biomarker identification in cancer susceptibility and metastasis studies. Here, we give a comprehensive overview of computational methods used for biomarker identification, and provide a performance comparison of several network models used in studies of cancer susceptibility, disease progression, and prognostication. Specifically, we evaluated implication networks, Boolean networks, Bayesian networks, and Pearson's correlation networks in constructing gene coexpression networks for identifying lung cancer diagnostic and prognostic biomarkers. The results show that implication networks, implemented in Genet package, identified sets of biomarkers that generated an accurate prediction of lung cancer risk and metastases; meanwhile, implication networks revealed more biologically relevant molecular interactions than Boolean networks, Bayesian networks, and Pearson's correlation networks when evaluated with MSigDB database. PMID:25392692

Guo, Nancy Lan; Wan, Ying-Wooi

2014-01-01

54

Network-Based Identification of Biomarkers Coexpressed with Multiple Pathways  

PubMed Central

Unraveling complex molecular interactions and networks and incorporating clinical information in modeling will present a paradigm shift in molecular medicine. Embedding biological relevance via modeling molecular networks and pathways has become increasingly important for biomarker identification in cancer susceptibility and metastasis studies. Here, we give a comprehensive overview of computational methods used for biomarker identification, and provide a performance comparison of several network models used in studies of cancer susceptibility, disease progression, and prognostication. Specifically, we evaluated implication networks, Boolean networks, Bayesian networks, and Pearson’s correlation networks in constructing gene coexpression networks for identifying lung cancer diagnostic and prognostic biomarkers. The results show that implication networks, implemented in Genet package, identified sets of biomarkers that generated an accurate prediction of lung cancer risk and metastases; meanwhile, implication networks revealed more biologically relevant molecular interactions than Boolean networks, Bayesian networks, and Pearson’s correlation networks when evaluated with MSigDB database. PMID:25392692

Guo, Nancy Lan; Wan, Ying-Wooi

2014-01-01

55

Oralmotor slowing in multiple sclerosis: Relationship to neuropsychological tasks requiring an oral response  

E-print Network

Oralmotor slowing in multiple sclerosis: Relationship to neuropsychological tasks requiring an oral with multiple sclerosis (MS) patients now exclude tests that require significant motor writing or manual­462.) Keywords: Multiple sclerosis, Neuropsychological functioning, Cognitive functioning, Oral motor speed

Dennis, Nancy

56

Distinct Signaling Mechanisms in Multiple Developmental Pathways by the SCRAMBLED Receptor of Arabidopsis1[OPEN  

PubMed Central

SCRAMBLED (SCM), a leucine-rich repeat receptor-like kinase in Arabidopsis (Arabidopsis thaliana), is required for positional signaling in the root epidermis and for tissue/organ development in the shoot. To further understand SCM action, we generated a series of kinase domain variants and analyzed their ability to complement scm mutant defects. We found that the SCM kinase domain, but not kinase activity, is required for its role in root epidermal patterning, supporting the view that SCM is an atypical receptor kinase. We also describe a previously uncharacterized role for SCM in fruit dehiscence, because mature siliques from scm mutants fail to open properly. Interestingly, the kinase domain of SCM appears to be dispensable for this developmental process. Furthermore, we found that most of the SCM kinase domain mutations dramatically inhibit inflorescence development. Because this process is not affected in scm null mutants, it is likely that SCM acts redundantly to regulate inflorescence size. The importance of distinct kinase residues for these three developmental processes provides an explanation for the maintenance of the conserved kinase domain in the SCM protein, and it may generally explain its conservation in other atypical kinases. Furthermore, these results indicate that individual leucine-rich repeat receptor-like kinases may participate in multiple pathways using distinct signaling mechanisms to mediate diverse cellular communication events. PMID:25136062

Kwak, Su-Hwan; Woo, Sooah; Lee, Myeong Min; Schiefelbein, John

2014-01-01

57

Multiple Pathways for Triacylglycerol Biosynthesis in Streptomyces coelicolor?  

PubMed Central

The terminal reaction in triacylglyceride (TAG) biosynthesis is the esterification of diacylglycerol (DAG) with a fatty acid molecule. To study this reaction in Streptomyces coelicolor, we analyzed three candidate genes (sco0958, sco1280, and sco0123) whose products significantly resemble the recently identified wax ester synthase/acyl-coenzyme A (CoA):DAG acyltransferase (DGAT) from Acinetobacter baylyi. The deletion of either sco0123 or sco1280 resulted in no detectable decrease in TAG accumulation. In contrast, the deletion of sco0958 produced a dramatic reduction in neutral lipid production, whereas the overexpression of this gene yielded a significant increase in de novo TAG biosynthesis. In vitro activity assays showed that Sco0958 mediates the esterification of DAG using long-chain acyl-CoAs (C14 to C18) as acyl donors. The Km and Vmax values of this enzyme for myristoyl-CoA were 45 ?M and 822 nmol mg?1 min?1, respectively. Significantly, the triple mutant strain was not completely devoid of storage lipids, indicating the existence of alternative TAG-biosynthetic routes. We present strong evidence demonstrating that the residual production of TAG in this mutant strain is mediated, at least in part, by an acyl-CoA-dependent pathway, since the triple mutant still exhibited DGAT activity. More importantly, there was substantial phospholipid:DGAT (PDAT) activity in the wild type and in the triple mutant. This is the first time that a PDAT activity has been reported for bacteria, highlighting the extreme metabolic diversity of this industrially important soil microorganism. PMID:18310412

Arabolaza, Ana; Rodriguez, Eduardo; Altabe, Silvia; Alvarez, Hector; Gramajo, Hugo

2008-01-01

58

The Drosophila Perlecan gene trol regulates multiple signaling pathways in different developmental contexts  

PubMed Central

Background Heparan sulfate proteoglycans modulate signaling by a variety of growth factors. The mammalian proteoglycan Perlecan binds and regulates signaling by Sonic Hedgehog, Fibroblast Growth Factors (FGFs), Vascular Endothelial Growth Factor (VEGF) and Platelet Derived Growth Factor (PDGF), among others, in contexts ranging from angiogenesis and cardiovascular development to cancer progression. The Drosophila Perlecan homolog trol has been shown to regulate the activity of Hedgehog and Branchless (an FGF homolog) to control the onset of stem cell proliferation in the developing brain during first instar. Here we extend analysis of trol mutant phenotypes to show that trol is required for a variety of developmental events and modulates signaling by multiple growth factors in different situations. Results Different mutations in trol allow developmental progression to varying extents, suggesting that trol is involved in multiple cell-fate and patterning decisions. Analysis of the initiation of neuroblast proliferation at second instar demonstrated that trol regulates this event by modulating signaling by Hedgehog and Branchless, as it does during first instar. Trol protein is distributed over the surface of the larval brain, near the regulated neuroblasts that reside on the cortical surface. Mutations in trol also decrease the number of circulating plasmatocytes. This is likely to be due to decreased expression of pointed, the response gene for VEGF/PDGF signaling that is required for plasmatocyte proliferation. Trol is found on plasmatocytes, where it could regulate VEGF/PDGF signaling. Finally, we show that in second instar brains but not third instar brain lobes and eye discs, mutations in trol affect signaling by Decapentaplegic (a Transforming Growth Factor family member), Wingless (a Wnt growth factor) and Hedgehog. Conclusion These studies extend the known functions of the Drosophila Perlecan homolog trol in both developmental and signaling contexts. These studies also highlight the fact that Trol function is not dedicated to a single molecular mechanism, but is capable of regulating different growth factor pathways depending on the cell-type and event underway. PMID:17980035

Lindner, Jonathan R; Hillman, Paul R; Barrett, Andrea L; Jackson, Megan C; Perry, Trinity L; Park, Youngji; Datta, Sumana

2007-01-01

59

Multiple cell death pathways are independently activated by lethal hypertonicity in renal epithelial cells.  

PubMed

When hypertonicity is imposed with sufficient intensity and acuteness, cells die. Here we investigated the cellular pathways involved in death using a cell line derived from renal epithelium. We found that hypertonicity rapidly induced activation of an intrinsic cell death pathway-release of cytochrome c and activation of caspase-3 and caspase-9-and an extrinsic pathway-activation of caspase-8. Likewise, a lysosomal pathway of cell death characterized by partial lysosomal rupture and release of cathepsin B from lysosomes to the cytosol was also activated. Relationships among the pathways were examined using specific inhibitors. Caspase inhibitors did not affect cathepsin B release into the cytosol by hypertonicity. In addition, cathepsin B inhibitors and caspase inhibitors did not affect hypertonicity-induced cytochrome c release, suggesting that the three pathways were independently activated. Combined inhibition of caspases and cathepsin B conferred significantly more protection from hypertonicity-induced cell death than inhibition of caspase or cathepsin B alone, indicating that all the three pathways contributed to the hypertonicity-induced cell death. Similar pattern of sensitivity to the inhibitors was observed in two other cell lines derived from renal epithelia. We conclude that multiple cell death pathways are independently activated early in response to lethal hypertonic stress in renal epithelial cells. PMID:23986196

Choi, Soo Youn; Lee-Kwon, Whaseon; Lee, Hwan Hee; Lee, Jun Ho; Sanada, Satoru; Kwon, Hyug Moo

2013-11-15

60

Multiple adaptable mechanisms early in the primate visual pathway  

PubMed Central

We describe experiments that isolate and characterize multiple adaptable mechanisms that influence responses of orientation-selective neurons in primary visual cortex (V1) of anesthetized macaque (Macaca fascicularis). The results suggest that three adaptable stages of machinery shape neural responses in V1: a broadly-tuned early stage and a spatio-temporally tuned later stage, both of which provide excitatory input, and a normalization pool that is also broadly tuned. The early stage and the normalization pool are revealed by adapting gratings that themselves fail to evoke a response from the neuron: either low temporal frequency gratings at the null orientation or gratings of any orientation drifting at high temporal frequencies. When effective, adapting stimuli that altered the sensitivity of these two mechanisms caused reductions of contrast gain and often brought about a paradoxical increase in response gain due to a relatively greater desensitization of the normalization pool. The tuned mechanism is desensitized only by stimuli well-matched to a neuron’s receptive field. We could thus infer desensitization of the tuned mechanism by comparing effects obtained with adapting gratings of preferred and null orientation modulated at low temporal frequencies. PMID:22016535

Dhruv, Neel T.; Tailby, Chris; Sokol, Sach H.; Lennie, Peter

2011-01-01

61

Multiple pathways of plasmid DNA transfer in Helicobacter pylori.  

PubMed

Many Helicobacter pylori (Hp) strains carry cryptic plasmids of different size and gene content, the function of which is not well understood. A subgroup of these plasmids (e.g. pHel4, pHel12), contain a mobilisation region, but no cognate type IV secretion system (T4SS) for conjugative transfer. Instead, certain H. pylori strains (e.g. strain P12 carrying plasmid pHel12) can harbour up to four T4SSs in their genome (cag-T4SS, comB, tfs3, tfs4). Here, we show that such indigenous plasmids can be efficiently transferred between H. pylori strains, even in the presence of extracellular DNaseI eliminating natural transformation. Knockout of a plasmid-encoded mobA relaxase gene significantly reduced plasmid DNA transfer in the presence of DNaseI, suggesting a DNA conjugation or mobilisation process. To identify the T4SS involved in this conjugative DNA transfer, each individual T4SS was consecutively deleted from the bacterial chromosome. Using a marker-free counterselectable gene deletion procedure (rpsL counterselection method), a P12 mutant strain was finally obtained with no single T4SS (P12?T4SS). Mating experiments using these mutants identified the comB T4SS in the recipient strain as the major mediator of plasmid DNA transfer between H. pylori strains, both in a DNaseI-sensitive (natural transformation) as well as a DNaseI-resistant manner (conjugative transfer). However, transfer of a pHel12::cat plasmid from a P12?T4SS donor strain into a P12?T4SS recipient strain provided evidence for the existence of a third, T4SS-independent mechanism of DNA transfer. This novel type of plasmid DNA transfer, designated as alternate DNaseI-Resistant (ADR) mechanism, is observed at a rather low frequency under in vitro conditions. Taken together, our study describes for the first time the existence of three distinct pathways of plasmid DNA transfer between H. pylori underscoring the importance of horizontal gene transfer for this species. PMID:23029142

Rohrer, Stefanie; Holsten, Lea; Weiss, Evelyn; Benghezal, Mohammed; Fischer, Wolfgang; Haas, Rainer

2012-01-01

62

Preparing Students for College and Career: California Multiple Pathways. Issue Brief  

ERIC Educational Resources Information Center

To prepare students for success in life, the twenty-first-century American high school needs to shift its focus from preparing for college or career to achieving college and career readiness for every student. One of the most comprehensive efforts towards this goal is the "multiple pathways" initiative in California, which is a reform model aimed…

Richmond, Eric

2009-01-01

63

Use of multiple dispersal pathways facilitates amphibian persistence in stream networks  

E-print Network

Use of multiple dispersal pathways facilitates amphibian persistence in stream networks Evan H. Campbell Granta,b,1 , James D. Nicholsa , Winsor H. Lowec , and William F. Fagand a Northeast Amphibian) Although populations of amphibians are declining worldwide, there is no evidence that salamanders occupying

Lowe, Winsor H.

64

Quantification of Bt-endotoxin exposure pathways in carabid food webs across multiple transgenic events  

Microsoft Academic Search

Despite the reported specificity of Bacillus thuringiensis proteins against target pests, a number of studies have indicated that the uptake of Bt-endotoxins from bioengineered crops could have negative effects on natural enemies. It is therefore essential to quantify exposure pathways in non-target arthropod food webs across multiple transgenic events. Adult ground beetles (Coleoptera: Carabidae) were collected from transgenic corn fields

Julie A. Peterson; John J. Obrycki; James D. Harwood

2009-01-01

65

Creating Multiple Pathways in the Arts: A New York City Case Study  

ERIC Educational Resources Information Center

Increasingly, education policy makers understand the importance of students and families having access to a range of high quality educational opportunities inside and outside of school, 365 days a year. This paper explores the concept of multiple pathways in arts education to further conceptualize and build upon such opportunities, inside and…

Maguire, Cindy; Mishook, Jacob; Garcia, Ivonne; de Gaillande, Genevieve

2013-01-01

66

Direct Observation of Multiple Pathways of Single-Stranded DNA Stretching  

NASA Astrophysics Data System (ADS)

We observed multiple pathways of stretching single-stranded polydeoxynucleotides, poly(dA). Poly(dA) has been shown to undergo unique transitions under mechanical force, and such transitions were attributed to the stacking characteristics of poly(dA). Using single-molecule manipulation studies, we found that poly(dA) has two stretching pathways at high forces. The previously observed pathway has a free energy that is less than what is expected of single-stranded DNA with a random sequence, indicating the existence of a novel conformation of poly(dA) at large extensions. We also observed stepwise transitions between the two pathways by pulling the molecule with constant force, and found that the transitions are cooperative. These results suggest that the unique mechanical property of poly(dA) may play an important role in biological processes such as gene expression.

Chen, Wuen-Shiu; Chen, Wei-Hung; Chen, Zephan; Gooding, Ashton A.; Lin, Kuan-Jiuh; Kiang, Ching-Hwa

2010-11-01

67

Direct sampling of multiple single-molecular rupture dominant pathways involving a multistep transition.  

PubMed

We report a novel single-molecular rupture mechanism revealed by direct sampling of the dominant pathway using a self-optimized path sampling method. Multiple dominant pathways involving multistep transitions are identified. The rupture may take place via a direct unfolding from the native state to the unfolding state, or through a two-step pathway bypassing a distinct intermediate metastable state (IMS). This scenario facilitates us to propose a three-state kinetic model, which can produce a nonlinear dependence of the rupture time on pulling forces similar to the ones reported in the literature. In particular, molecule conformations in the IMS maintain an elongation of the tail at one terminal, by which external pulling will enhance the relative stability of IMS. Consequently, even though the overall transition rate of the multistep pathway is relatively small, the molecule still has to be ruptured via the multistep pathway rather than the direct pathway. Thus, our work demonstrates an IMS trapping effect induced rupture mechanism involving an abnormal switching from a fast dominant pathway to a slow one. PMID:25347216

Jiang, Huijun; Ding, Huai; Hou, Zhonghuai

2014-12-14

68

Genetic and Epigenetic Events Generate Multiple Pathways in Colorectal Cancer Progression  

PubMed Central

Colorectal cancer (CRC) is one of the most common causes of death, despite decades of research. Initially considered as a disease due to genetic mutations, it is now viewed as a complex malignancy because of the involvement of epigenetic abnormalities. A functional equivalence between genetic and epigenetic mechanisms has been suggested in CRC initiation and progression. A hallmark of CRC is its pathogenetic heterogeneity attained through at least three distinct pathways: a traditional (adenoma-carcinoma sequence), an alternative, and more recently the so-called serrated pathway. While the alternative pathway is more heterogeneous and less characterized, the traditional and serrated pathways appear to be more homogeneous and clearly distinct. One unsolved question in colon cancer biology concerns the cells of origin and from which crypt compartment the different pathways originate. Based on molecular and pathological evidences, we propose that the traditional and serrated pathways originate from different crypt compartments explaining their genetic/epigenetic and clinicopathological differences. In this paper, we will discuss the current knowledge of CRC pathogenesis and, specifically, summarize the role of genetic/epigenetic changes in the origin and progression of the multiple CRC pathways. Elucidation of the link between the molecular and clinico-pathological aspects of CRC would improve our understanding of its etiology and impact both prevention and treatment. PMID:22888469

Pancione, Massimo; Remo, Andrea; Colantuoni, Vittorio

2012-01-01

69

Biasing a transition state search to locate multiple reaction pathways Baron Peters, WanZhen Liang, and Alexis T. Bell  

E-print Network

case, four reaction pathways were discovered: two exothermic conrotatory ring openings leading to hexadienes, an endothermic methyl migration pathway leading to a carbene, and an exothermic rearrangementBiasing a transition state search to locate multiple reaction pathways Baron Peters, WanZhen Liang

Bell, Alexis T.

70

Thermal comfort requirements: A study of people with multiple sclerosis  

SciTech Connect

Existing specifications for thermal comfort in built environments are coming under increased criticism for failing to consider the requirements of specific populations. People with physical disabilities are an example of one such population. This paper presents the results of a study on the thermal comfort requirements of 32 people with multiple sclerosis. Subjects were exposed to three conditions: 18.5 C, PMV = {minus}1.5, slightly cool to cool; 23 C, PMV = 0, neutral; 29 C, PMV = +1.5, slightly warm to warm. Results indicate that people with multiple sclerosis have a wide range of responses to the three experimental conditions. The actual percentage dissatisfied was much higher than predicted by Fange's (1970) predicted percentage dissatisfied. Their preferred environment is slightly warmer than 23 C, PMV = 0, neutral. A subgroup of the population prefers an environment that is slightly cooler than 23 C. Further work is needed to qualify if their preferred environments match that of PMV+1 and PMV{minus}1 and to identify if any of the factors such as age, duration of disability, and medication affect the actual mean vote.

Webb, L.H.; Parsons, K.C.; Hodder, S.G.

1999-07-01

71

The toll-dorsal pathway is required for resistance to viral oral infection in Drosophila.  

PubMed

Pathogen entry route can have a strong impact on the result of microbial infections in different hosts, including insects. Drosophila melanogaster has been a successful model system to study the immune response to systemic viral infection. Here we investigate the role of the Toll pathway in resistance to oral viral infection in D. melanogaster. We show that several Toll pathway components, including Spätzle, Toll, Pelle and the NF-kB-like transcription factor Dorsal, are required to resist oral infection with Drosophila C virus. Furthermore, in the fat body Dorsal is translocated from the cytoplasm to the nucleus and a Toll pathway target gene reporter is upregulated in response to Drosophila C Virus infection. This pathway also mediates resistance to several other RNA viruses (Cricket paralysis virus, Flock House virus, and Nora virus). Compared with control, viral titres are highly increased in Toll pathway mutants. The role of the Toll pathway in resistance to viruses in D. melanogaster is restricted to oral infection since we do not observe a phenotype associated with systemic infection. We also show that Wolbachia and other Drosophila-associated microbiota do not interact with the Toll pathway-mediated resistance to oral infection. We therefore identify the Toll pathway as a new general inducible pathway that mediates strong resistance to viruses with a route-specific role. These results contribute to a better understanding of viral oral infection resistance in insects, which is particularly relevant in the context of transmission of arboviruses by insect vectors. PMID:25473839

Ferreira, Alvaro Gil; Naylor, Huw; Esteves, Sara Santana; Pais, Inês Silva; Martins, Nelson Eduardo; Teixeira, Luis

2014-12-01

72

The Toll-Dorsal Pathway Is Required for Resistance to Viral Oral Infection in Drosophila  

PubMed Central

Pathogen entry route can have a strong impact on the result of microbial infections in different hosts, including insects. Drosophila melanogaster has been a successful model system to study the immune response to systemic viral infection. Here we investigate the role of the Toll pathway in resistance to oral viral infection in D. melanogaster. We show that several Toll pathway components, including Spätzle, Toll, Pelle and the NF-kB-like transcription factor Dorsal, are required to resist oral infection with Drosophila C virus. Furthermore, in the fat body Dorsal is translocated from the cytoplasm to the nucleus and a Toll pathway target gene reporter is upregulated in response to Drosophila C Virus infection. This pathway also mediates resistance to several other RNA viruses (Cricket paralysis virus, Flock House virus, and Nora virus). Compared with control, viral titres are highly increased in Toll pathway mutants. The role of the Toll pathway in resistance to viruses in D. melanogaster is restricted to oral infection since we do not observe a phenotype associated with systemic infection. We also show that Wolbachia and other Drosophila-associated microbiota do not interact with the Toll pathway-mediated resistance to oral infection. We therefore identify the Toll pathway as a new general inducible pathway that mediates strong resistance to viruses with a route-specific role. These results contribute to a better understanding of viral oral infection resistance in insects, which is particularly relevant in the context of transmission of arboviruses by insect vectors. PMID:25473839

Ferreira, Álvaro Gil; Naylor, Huw; Esteves, Sara Santana; Pais, Inês Silva; Martins, Nelson Eduardo; Teixeira, Luis

2014-01-01

73

Mycobacterial Esx-3 Requires Multiple Components for Iron Acquisition  

PubMed Central

ABSTRACT The type VII secretion systems are conserved across mycobacterial species and in many Gram-positive bacteria. While the well-characterized Esx-1 pathway is required for the virulence of pathogenic mycobacteria and conjugation in the model organism Mycobacterium smegmatis, Esx-3 contributes to mycobactin-mediated iron acquisition in these bacteria. Here we show that several Esx-3 components are individually required for function under low-iron conditions but that at least one, the membrane-bound protease MycP3 of M. smegmatis, is partially expendable. All of the esx-3 mutants tested, including the ?mycP3ms mutant, failed to export the native Esx-3 substrates EsxHms and EsxGms to quantifiable levels, as determined by targeted mass spectrometry. Although we were able to restore low-iron growth to the esx-3 mutants by genetic complementation, we found a wide range of complementation levels for protein export. Indeed, minute quantities of extracellular EsxHms and EsxGms were sufficient for iron acquisition under our experimental conditions. The apparent separation of Esx-3 function in iron acquisition from robust EsxGms and EsxHms secretion in the ?mycP3ms mutant and in some of the complemented esx-3 mutants compels reexamination of the structure-function relationships for type VII secretion systems. PMID:24803520

Siegrist, M. Sloan; Steigedal, Magnus; Ahmad, Rushdy; Mehra, Alka; Dragset, Marte S.; Schuster, Brian M.; Philips, Jennifer A.; Carr, Steven A.

2014-01-01

74

Classical and/or alternative NF-?B pathway activation in multiple myeloma  

PubMed Central

Mutations involving the nuclear factor-?B (NF-?B) pathway are present in at least 17% of multiple myeloma (MM) tumors and 40% of MM cell lines (MMCLs). These mutations, which are apparent progression events, enable MM tumors to become less dependent on bone marrow signals that activate NF-?B. Studies on a panel of 51 MMCLs provide some clarification of the mechanisms through which these mutations act and the significance of classical versus alternative activation of NF-?B. First, only one mutation (NFKB2) selectively activates the alternative pathway, whereas several mutations (CYLD, NFKB1, and TACI) selectively activate the classical pathway. However, most mutations affecting NF-?B–inducing kinase (NIK) levels (NIK, TRAF2, TRAF3, cIAP1&2, and CD40) activate the alternative but often both pathways. Second, we confirm the critical role of TRAF2 in regulating NIK degradation, whereas TRAF3 enhances but is not essential for cIAP1/2-mediated proteasomal degradation of NIK in MM. Third, using transfection to selectively activate the classical or alternative NF-?B pathways, we show virtually identical changes in gene expression in one MMCL, whereas the changes are similar albeit nonidentical in a second MMCL. Our results suggest that MM tumors can achieve increased autonomy from the bone marrow microenvironment by mutations that activate either NF-?B pathway. PMID:20053756

Demchenko, Yulia N.; Glebov, Oleg K.; Zingone, Adriana; Keats, Jonathan J.; Bergsagel, P. Leif

2010-01-01

75

Parallel inactivation of multiple GAL pathway genes and ecological diversification in yeasts  

PubMed Central

Understanding the evolutionary relationship between genome content and ecological niche is one of the fundamental challenges of biology. The distinct physiologies of yeast species provide a window into how genomes evolve in concert with niche. Although the enzymes of the well studied yeast galactose utilization pathway are present in all domains of life, we have found that multiple genes of the GAL pathway are absent from four yeast species that cannot use galactose. Whereas three species lack any trace of the pathway except a single gene, Saccharomyces kudriavzevii, a close relative of Saccharomyces cerevisiae, retains remnants of all seven dedicated GAL genes as syntenic pseudogenes, providing a rare glimpse of an entire pathway in the process of degeneration. An estimate of the timing of gene inactivation suggests that pathway degeneration began early in the lineage and proceeded rapidly. S. kudriavzevii exhibits several other divergent physiological properties that are associated with a shift in ecological niche. These results suggest that rapid and irreversible gene inactivation and pathway degeneration are associated with adaptation to new ecological niches in natural populations. Inactivated genes may generally serve as markers of specific functions made dispensable by recent adaptive shifts. PMID:15381776

Hittinger, Chris Todd; Rokas, Antonis; Carroll, Sean B.

2004-01-01

76

Multiple Achievement Goals and Multiple Pathways for Learning: The Agenda and Impact of Paul R. Pintrich  

ERIC Educational Resources Information Center

This article considers the profound impact that Paul R. Pintrich had on the field of achievement motivation, specifically achievement goal theory. The article highlights Pintrich's groundbreaking research and theorizing, beginning with his early work integrating research on motivation and cognition and ending with his development of a multiple

Harackiewicz, Judith M.; Linnenbrink, Elizabeth A.

2005-01-01

77

Pathway and network-based analysis of genome-wide association studies in multiple sclerosis  

PubMed Central

Genome-wide association studies (GWAS) testing several hundred thousand SNPs have been performed in multiple sclerosis (MS) and other complex diseases. Typically, the number of markers in which the evidence for association exceeds the genome-wide significance threshold is very small, and markers that do not exceed this threshold are generally neglected. Classical statistical analysis of these datasets in MS revealed genes with known immunological functions. However, many of the markers showing modest association may represent false negatives. We hypothesize that certain combinations of genes flagged by these markers can be identified if they belong to a common biological pathway. Here we conduct a pathway-oriented analysis of two GWAS in MS that takes into account all SNPs with nominal evidence of association (P < 0.05). Gene-wise P-values were superimposed on a human protein interaction network and searches were conducted to identify sub-networks containing a higher proportion of genes associated with MS than expected by chance. These sub-networks, and others generated at random as a control, were categorized for membership of biological pathways. GWAS from eight other diseases were analyzed to assess the specificity of the pathways identified. In the MS datasets, we identified sub-networks of genes from several immunological pathways including cell adhesion, communication and signaling. Remarkably, neural pathways, namely axon-guidance and synaptic potentiation, were also over-represented in MS. In addition to the immunological pathways previously identified, we report here for the first time the potential involvement of neural pathways in MS susceptibility. PMID:19286671

Baranzini, Sergio E.; Galwey, Nicholas W.; Wang, Joanne; Khankhanian, Pouya; Lindberg, Raija; Pelletier, Daniel; Wu, Wen; Uitdehaag, Bernard M.J.; Kappos, Ludwig; Polman, Chris H.; Matthews, Paul M.; Hauser, Stephen L.; Gibson, Rachel A.; Oksenberg, Jorge R.; Barnes, Michael R.

2009-01-01

78

Synergy between Multiple Microtubule-Generating Pathways Confers Robustness to Centrosome-Driven Mitotic Spindle Formation  

PubMed Central

Summary The mitotic spindle is defined by its organized, bipolar mass of microtubules, which drive chromosome alignment and segregation. Although different cells have been shown to use different molecular pathways to generate the microtubules required for spindle formation, how these pathways are coordinated within a single cell is poorly understood. We have tested the limits within which the Drosophila embryonic spindle forms, disrupting the inherent temporal control that overlays mitotic microtubule generation, interfering with the molecular mechanism that generates new microtubules from preexisting ones, and disrupting the spatial relationship between microtubule nucleation and the usually dominant centrosome. Our work uncovers the possible routes to spindle formation in embryos and establishes the central role of Augmin in all microtubule-generating pathways. It also demonstrates that the contributions of each pathway to spindle formation are integrated, highlighting the remarkable flexibility with which cells can respond to perturbations that limit their capacity to generate microtubules. PMID:24389063

Hayward, Daniel; Metz, Jeremy; Pellacani, Claudia; Wakefield, James G.

2014-01-01

79

Multiple pathways from three types of sugar receptor sites to metabotropic transduction pathways of the blowfly: study by the whole cell-clamp experiments.  

PubMed

Multiple pathways from three types of multiple receptor sites to three types of metabotropic signal transduction pathways were investigated in the whole cell-clamp experiments using isolated labellar sugar receptor neurons (cells) of the adult blowfly, Phormia regina. First, the concentration-response curves of three types of sweet taste components specialized to multiple receptor sites were obtained: sucrose for the pyranose sites (P-sites), fructose for the furanose sites (F-sites), and l-valine for the alkyl sites (R-sites). Next, the effects of inhibitors such as 2', 5'-dideoxyadenosine on adenylyl cyclase in the cAMP pathway, LY 83583 on guanylyl cyclase in the cGMP pathway, and U-73122 on phospholipase C in the IP? pathway were examined. The results showed that all of the inhibitors affected each specific target in the second-messenger transduction pathways. The obtained results verified that the P-site corresponded to the cAMP, the F-site to the cGMP, and the R-site to the IP? transduction pathway, and that these three signal pathways did not have crossing points. PMID:21624494

Kan, Hideko; Kataoka-Shirasugi, Naoko; Amakawa, Taisaku

2011-09-01

80

Depression's multiple comorbidities explained by (neuro)inflammatory and oxidative & nitrosative stress pathways.  

PubMed

There is now evidence that depression, as characterized by melancholic symptoms, anxiety, and fatigue and somatic (F&S) symptoms, is the clinical expression of peripheral cell-mediated activation, inflammation and induction of oxidative and nitrosative stress (IO&NS) pathways and of central microglial activation, decreased neurogenesis and increased apoptosis. This review gives an explanation for the multiple "co-morbidities" between depression and a large variety of a) brain disorders related to neurodegeneration, e.g. Alzheimer's, Parkinson's and Huntington's disease, multiple sclerosis and stroke; b) medical disorders, such as cardiovascular disorder, chronic fatigue syndrome, chronic obstructive pulmonary disease, rheumatoid arthritis, psoriasis, systemic lupus erythematosus, inflammatory bowel disease, irritable bowel syndrome, leaky gut, diabetes type 1 and 2, obesity and the metabolic syndrome, and HIV infection; and c) conditions, such as hemodialysis, interferon-?-based immunotherapy, the postnatal period and psychosocial stressors. The common denominator of all those disorders/conditions is the presence of microglial activation and/or activation of peripheral IO&NS pathways. There is evidence that shared peripheral and / or central IO&NS pathways underpin the pathophysiology of depression and the previously mentioned disorders and that activation of these IO&NS pathways contributes to shared risk. The IO&NS pathways function as a smoke sensor that detect threats in the peripheral and central parts of the body and signal these threats as melancholic, anxiety, and fatigue and somatic (F&S) symptoms. The presence of concomitant depression is strongly associated with a lower quality of life and increased morbidity and mortality in medical disorders. This may be explained since depression contributes to increased (neuro)inflammatory burden and may therefore drive the inflammatory and degenerative progression. It is concluded that the activation of peripheral and / or central IO&NS pathways may explain the co-occurrence of depression with the above disorders. This shows that depression belongs to the spectrum of inflammatory and degenerative disorders. PMID:21407167

Maes, Michael; Kubera, Marta; Obuchowiczwa, Ewa; Goehler, Lisa; Brzeszcz, Joanna

2011-01-01

81

Therapeutic Efficacy of Suppressing the JAK/STAT Pathway in Multiple Models of EAE1  

PubMed Central

Pathogenic T helper cells and myeloid cells are involved in the pathogenesis of Multiple Sclerosis (MS) and Experimental Autoimmune Encephalomyelitis (EAE), an animal model of MS. The JAK/STAT pathway is utilized by numerous cytokines for signaling, and is critical for development, regulation and termination of immune responses. Dysregulation of the JAK/STAT pathway has pathological implications in autoimmune and neuroinflammatory diseases. Many of the cytokines involved in MS/EAE, including IL-6, IL-12, IL-23, IFN-? and GM-CSF, use the JAK/STAT pathway to induce biological responses. Thus, targeting JAKs has implications for treating autoimmune inflammation of the brain. We have utilized AZD1480, a JAK1/2 inhibitor, to investigate the therapeutic potential of inhibiting the JAK/STAT pathway in models of EAE. AZD1480 treatment inhibits disease severity in MOG-induced classical and atypical EAE models by preventing entry of immune cells into the brain, suppressing differentiation of Th1 and Th17 cells, deactivating myeloid cells, inhibiting STAT activation in the brain, and reducing expression of pro-inflammatory cytokines and chemokines. Treatment of SJL/J mice with AZD1480 delays disease onset of PLP-induced relapsing-remitting disease, reduces relapses and diminishes clinical severity. AZD1480 treatment was also effective in reducing ongoing paralysis induced by adoptive transfer of either pathogenic Th1 or Th17 cells. In vivo AZD1480 treatment impairs both the priming and expansion of T-cells, and attenuates antigen-presentation functions of myeloid cells. Inhibition of the JAK/STAT pathway has clinical efficacy in multiple pre-clinical models of MS, suggesting the feasibility of the JAK/STAT pathway as a target for neuroinflammatory diseases. PMID:24323580

Liu, Yudong; Holdbrooks, Andrew T.; De Sarno, Patrizia; Rowse, Amber L.; Yanagisawa, Lora L.; McFarland, Braden C.; Harrington, Laurie E.; Raman, Chander; Sabbaj, Steffanie; Benveniste, Etty N.; Qin, Hongwei

2014-01-01

82

Multiple Requirements of PLK1 during Mouse Oocyte Maturation  

PubMed Central

Polo-like kinase 1 (PLK1) orchestrates multiple events of cell division. Although PLK1 function has been intensively studied in centriole-containing and rapidly cycling somatic cells, much less is known about its function in the meiotic divisions of mammalian oocytes, which arrest for a long period of time in prophase before meiotic resumption and lack centrioles for spindle assembly. Here, using specific small molecule inhibition combined with live mouse oocyte imaging, we comprehensively characterize meiotic PLK1’s functions. We show that PLK1 becomes activated at meiotic resumption on microtubule organizing centers (MTOCs) and later at kinetochores. PLK1 is required for efficient meiotic resumption by promoting nuclear envelope breakdown. PLK1 is also needed to recruit centrosomal proteins to acentriolar MTOCs to promote normal spindle formation, as well as for stable kinetochore-microtubule attachment. Consequently, PLK1 inhibition leads to metaphase I arrest with misaligned chromosomes activating the spindle assembly checkpoint (SAC). Unlike in mitosis, the metaphase I arrest is not bypassed by the inactivation of the SAC. We show that PLK1 is required for the full activation of the anaphase promoting complex/cyclosome (APC/C) by promoting the degradation of the APC/C inhibitor EMI1 and is therefore essential for entry into anaphase I. Moreover, our data suggest that PLK1 is required for proper chromosome segregation and the maintenance of chromosome condensation during the meiosis I-II transition, independently of the APC/C. Thus, our results define the meiotic roles of PLK1 in oocytes and reveal interesting differential requirements of PLK1 between mitosis and oocyte meiosis in mammals. PMID:25658810

Solc, Petr; Kitajima, Tomoya S.; Yoshida, Shuhei; Brzakova, Adela; Kaido, Masako; Baran, Vladimir; Mayer, Alexandra; Samalova, Pavlina; Motlik, Jan; Ellenberg, Jan

2015-01-01

83

Multiple functions of MRN in end-joining pathways during isotype class switching  

PubMed Central

Summary The Mre11/Rad50/NBS1 (MRN) complex plays many roles in response to DNA double strand breaks (DSBs), but its functions in repair by non homologous end joining (NHEJ) pathways are poorly understood. We have investigated requirements for MRN in Class Switch Recombination (CSR), a programmed DNA rearrangement in B lymphocytes that requires NHEJ. To this end we have engineered mice that lack the entire MRN complex in B lymphocytes, or possess an intact complex harboring mutant Mre11 lacking DNA nuclease activities. MRN deficiency confers a striking defect in CSR, impacting both the Classic and Alternative NHEJ pathways. In contrast, absence of Mre11 nuclease activities causes a milder phenotype, revealing a separation of function within the complex. We propose a model in which MRN stabilizes distant breaks and processes DNA termini to facilitate repair by both the Classical and Alternative NHEJ pathways. PMID:19633670

Dinkelmann, Maria; Spehalski, Elizabeth; Stoneham, Trina; Buis, Jeffrey; Wu, Yipin; Sekiguchi, JoAnn M.; Ferguson, David O.

2009-01-01

84

Multiple functions of MRN in end-joining pathways during isotype class switching.  

PubMed

The Mre11-Rad50-NBS1 (MRN) complex has many roles in response to DNA double-strand breaks, but its functions in repair by nonhomologous end joining (NHEJ) pathways are poorly understood. We have investigated requirements for MRN in class switch recombination (CSR), a programmed DNA rearrangement in B lymphocytes that requires NHEJ. To this end, we have engineered mice that lack the entire MRN complex in B lymphocytes or that possess an intact complex that harbors mutant Mre11 lacking DNA nuclease activities. MRN deficiency confers a strong defect in CSR, affecting both the classic and the alternative NHEJ pathways. In contrast, absence of Mre11 nuclease activities causes a milder phenotype, revealing a separation of function within the complex. We propose a model in which MRN stabilizes distant breaks and processes DNA termini to facilitate repair by both the classical and alternative NHEJ pathways. PMID:19633670

Dinkelmann, Maria; Spehalski, Elizabeth; Stoneham, Trina; Buis, Jeffrey; Wu, Yipin; Sekiguchi, JoAnn M; Ferguson, David O

2009-08-01

85

A DNA repair pathway score predicts survival in human multiple myeloma: the potential for therapeutic strategy  

PubMed Central

DNA repair is critical to resolve extrinsic or intrinsic DNA damage to ensure regulated gene transcription and DNA replication. These pathways control repair of double strand breaks, interstrand crosslinks, and nucleotide lesions occurring on single strands. Distinct DNA repair pathways are highly inter-linked for the fast and optimal DNA repair. A deregulation of DNA repair pathways may maintain and promote genetic instability and drug resistance to genotoxic agents in tumor cells by specific mechanisms that tolerate or rapidly bypass lesions to drive proliferation and abrogate cell death. Multiple Myeloma (MM) is a plasma cell disorder characterized by genetic instability and poor outcome for some patients, in which the compendium of DNA repair pathways has as yet not been assessed for a disease-specific prognostic relevance. We design a DNA repair risk score based on the expression of genes coding for proteins involved in DNA repair in MM cells. From a consensus list of 84 DNA repair genes, 17 had a bad prognostic value and 5 a good prognostic value for both event-free and overall survival of previously-untreated MM patients. The prognostic information provided by these 22 prognostic genes was summed within a global DNA repair score (DRScore) to take into account the tight linkage of repair pathways. DRscore was strongly predictive for both patients' event free and overall survivals. Also, DRscore has the potential to identify MM patients whose tumor cells are dependent on specific DNA repair pathways to design treatments that induce synthetic lethality by exploiting addiction to deregulated DNA repair pathways. PMID:24809299

Kassambara, Alboukadel; Gourzones-Dmitriev, Claire; Sahota, Surinder; Rème, Thierry; Moreaux, Jérôme; Goldschmidt, Hartmut; Constantinou, Angelos; Pasero, Philippe; Hose, Dirk; Klein, Bernard

2014-01-01

86

Humidity sensation requires both mechanosensory and thermosensory pathways in Caenorhabditis elegans  

PubMed Central

All terrestrial animals must find a proper level of moisture to ensure their health and survival. The cellular-molecular basis for sensing humidity is unknown in most animals, however. We used the model nematode Caenorhabditis elegans to uncover a mechanism for sensing humidity. We found that whereas C. elegans showed no obvious preference for humidity levels under standard culture conditions, worms displayed a strong preference after pairing starvation with different humidity levels, orienting to gradients as shallow as 0.03% relative humidity per millimeter. Cell-specific ablation and rescue experiments demonstrate that orientation to humidity in C. elegans requires the obligatory combination of distinct mechanosensitive and thermosensitive pathways. The mechanosensitive pathway requires a conserved DEG/ENaC/ASIC mechanoreceptor complex in the FLP neuron pair. Because humidity levels influence the hydration of the worm’s cuticle, our results suggest that FLP may convey humidity information by reporting the degree that subcuticular dendritic sensory branches of FLP neurons are stretched by hydration. The thermosensitive pathway requires cGMP-gated channels in the AFD neuron pair. Because humidity levels affect evaporative cooling, AFD may convey humidity information by reporting thermal flux. Thus, humidity sensation arises as a metamodality in C. elegans that requires the integration of parallel mechanosensory and thermosensory pathways. This hygrosensation strategy, first proposed by Thunberg more than 100 y ago, may be conserved because the underlying pathways have cellular and molecular equivalents across a wide range of species, including insects and humans. PMID:24843133

Russell, Joshua; Vidal-Gadea, Andrés G.; Makay, Alex; Lanam, Carolyn; Pierce-Shimomura, Jonathan T.

2014-01-01

87

Activation of Multiple Apoptotic Pathways in Human Nasopharyngeal Carcinoma Cells by the Prenylated Isoflavone, Osajin  

PubMed Central

Osajin is a prenylated isoflavone showing antitumor activity in different tumor cell lines. The underlying mechanism of osajin-induced cancer cell death is not clearly understood. In the present study, the mechanisms of osajin-induced cell death of human nasopharyngeal carcinoma (NPC) cells were explored. Osajin was found to significantly induce apoptosis of NPC cells in a dose- and time-dependent manner. Multiple molecular effects were observed during osajin treatment including a significant loss of mitochondrial transmembrane potential, release of cytochrome c into the cytosol, enhanced expression of Fas ligand (FasL), suppression of glucose-regulated protein 78 kDa (GRP78), and activation of caspases-9, -8, -4 and -3. In addition, up-regulation of proapoptotic Bax protein and down-regulation of antiapoptotic Bcl-2 protein were also observed. Taken together, osajin induces apoptosis in human NPC cells through multiple apoptotic pathways, including the extrinsic death receptor pathway, and intrinsic pathways relying on mitochondria and endoplasmic reticulum stress. Thus, osajin could be developed as a new effective and chemopreventive compound for human NPC. PMID:21532751

Huang, Tsung-Teng; Liu, Fu-Guo; Wei, Chia-Fong; Lu, Chia-Chen; Chen, Chang-Chieh; Lin, Hung-Chi; Ojcius, David M.; Lai, Hsin-Chih

2011-01-01

88

Ptr ToxA requires multiple motifs for complete activity.  

PubMed

Ptr ToxA was the first proteinaceous necrosis-inducing toxin identified and cloned from the wheat pathogen, Pyrenophora tritici-repentis. How this protein causes necrosis in sensitive wheat cultivars is not known. In an effort to understand the structural features of Ptr ToxA required for induction of necrosis, we employed a combination of site-directed mutagenesis and peptide inhibition studies. Mutagenesis was carried out on conserved motifs within the active domain of Ptr ToxA. Proteins with mutations of potential casein kinase 2 phosphorylation sites but not protein kinase C phosphorylation sites have significantly reduced activity. Additionally, mutations in a region with high homology to amino acids surrounding and including the RGD cell attachment motif of vitronectin result in proteins with significantly less activity than Ptr ToxA. The importance of the vitronectin-like motif was confirmed by a decrease of Ptr ToxA-induced activity when coinfiltrated with peptides corresponding to amino acids within this motif. Reduction in Ptr ToxA activity by competition with mutant proteins demonstrates the necessity of multiple motifs for Ptr ToxA activity. PMID:15141953

Manning, Viola A; Andrie, Rachael M; Trippe, Aaron F; Ciuffetti, Lynda M

2004-05-01

89

A G alpha-dependent pathway that antagonizes multiple chemoattractant responses that regulate directional cell movement.  

PubMed

Chemotactic cells, including neutrophils and Dictyostelium discoideum, orient and move directionally in very shallow chemical gradients. As cells polarize, distinct structural and signaling components become spatially constrained to the leading edge or rear of the cell. It has been suggested that complex feedback loops that function downstream of receptor signaling integrate activating and inhibiting pathways to establish cell polarity within such gradients. Much effort has focused on defining activating pathways, whereas inhibitory networks have remained largely unexplored. We have identified a novel signaling function in Dictyostelium involving a Galpha subunit (Galpha9) that antagonizes broad chemotactic response. Mechanistically, Galpha9 functions rapidly following receptor stimulation to negatively regulate PI3K/PTEN, adenylyl cyclase, and guanylyl cyclase pathways. The coordinated activation of these pathways is required to establish the asymmetric mobilization of actin and myosin that typifies polarity and ultimately directs chemotaxis. Most dramatically, cells lacking Galpha9 have extended PI(3,4,5)P(3), cAMP, and cGMP responses and are hyperpolarized. In contrast, cells expressing constitutively activated Galpha9 exhibit a reciprocal phenotype. Their second message pathways are attenuated, and they have lost the ability to suppress lateral pseudopod formation. Potentially, functionally similar Galpha-mediated inhibitory signaling may exist in other eukaryotic cells to regulate chemoattractant response. PMID:15059962

Brzostowski, Joseph A; Parent, Carole A; Kimmel, Alan R

2004-04-01

90

A G?-dependent pathway that antagonizes multiple chemoattractant responses that regulate directional cell movement  

PubMed Central

Chemotactic cells, including neutrophils and Dictyostelium discoideum, orient and move directionally in very shallow chemical gradients. As cells polarize, distinct structural and signaling components become spatially constrained to the leading edge or rear of the cell. It has been suggested that complex feedback loops that function downstream of receptor signaling integrate activating and inhibiting pathways to establish cell polarity within such gradients. Much effort has focused on defining activating pathways, whereas inhibitory networks have remained largely unexplored. We have identified a novel signaling function in Dictyostelium involving a G? subunit (G?9) that antagonizes broad chemotactic response. Mechanistically, G?9 functions rapidly following receptor stimulation to negatively regulate PI3K/PTEN, adenylyl cyclase, and guanylyl cyclase pathways. The coordinated activation of these pathways is required to establish the asymmetric mobilization of actin and myosin that typifies polarity and ultimately directs chemotaxis. Most dramatically, cells lacking G?9 have extended PI(3,4,5)P3, cAMP, and cGMP responses and are hyperpolarized. In contrast, cells expressing constitutively activated G?9 exhibit a reciprocal phenotype. Their second message pathways are attenuated, and they have lost the ability to suppress lateral pseudopod formation. Potentially, functionally similar G?-mediated inhibitory signaling may exist in other eukaryotic cells to regulate chemoattractant response. PMID:15059962

Brzostowski, Joseph A.; Parent, Carole A.; Kimmel, Alan R.

2004-01-01

91

Initiation of Rhombomeric Hoxb4 Expression Requires Induction by Somites and a Retinoid Pathway  

Microsoft Academic Search

Anteroposterior (AP) patterning in the vertebrate hindbrain is dependent upon the establishment of segmental domains of Hox expression. We investigated the mechanism that governs the early expression of Hoxb4 and found that transient signaling from the paraxial mesoderm induces expression in the hindbrain. Induction involves a retinoid pathway requiring retinoic acid receptor (RAR) function within the neural plate. Characterization of

Alex Gould; Nobue Itasaki; Robb Krumlauf

1998-01-01

92

Multiple pathways in nuclear transport: the import of U2 snRNP occurs by a novel kinetic pathway  

PubMed Central

Protein import to the nucleus is a signal-mediated process that exhibits saturation kinetics. We investigated whether signal bearing proteins compete with U2 and U6 snRNPs during import. When injected into Xenopus oocytes, saturating concentrations of P(Lys)-BSA, a protein bearing multiple nuclear localization signals from SV40 large T- antigen, reduce the rate of [125I]P(Lys)-BSA and of [125I]nucleoplasmin import, consistent with their competing for and sharing the same limiting component of the import apparatus. In contrast, saturating concentrations of P(Lys)-BSA do not reduce the rate of HeLa [32P]U2 snRNP assembly or import. The import of U6 snRNP is also competed by P(Lys)-BSA. We conclude that U2 snRNP is imported into oocyte nuclei by a kinetic pathway that is distinct from the one followed by P(Lys)-BSA, nucleoplasmin, and U6 snRNP. PMID:1824847

1991-01-01

93

Apoptosis of bone marrow mesenchymal stem cells caused by hypoxia/reoxygenation via multiple pathways  

PubMed Central

The irreversible loss of cardiomyocytes remains a key problem to resolve, which forms the cellular basis of cardiac dysfunction. MSCs transplantation brings out a promising potential for myocardial renovation with less limitations. However, this cell transplantation therapy is limited by its poor viability after transplantation. Apoptosis is thought to be the major factor that affects the efficiency of MSCs transplantation. Therefore, exploring the process of apoptosis and the underlying mechanisms of MSCs in the ‘harmful’ microenvironment is significant for the sake of improving the efficiency of MSCs transplantation therapy. A hypoxia/reoxygenation (H/R) model of MSCs had been established. TUNEL, Hoechst staining and MTT were used for the evaluation of morphological changes, cell viability and apoptosis. Mitochondrial transmembrane potential was detected by JC-1 using the fluorescence microscopy system. The protein expression of cytochrome c, p-ERK, p-AKT, Bcl-2, Bax, p-JNK, HIF-1? and VEGF was assessed for the analysis of protein changes using the Western blot. In our study, H/R insult lead to apoptosis and cell viability lost in a time-dependent manner in MSCs. Multiple pathways were involved in the apoptosis of MSCs, including cytochrome c released from mitochondria to cytosol, mitochondrial transmembrane potential lost. In addition, p-ERK and p-AKT were downregulated, while Bcl-2, p-JNK and VEGF were upregulated. H/R induced the apoptosis in MSCs is through multiple pathways. These multiple pathways will be helpful for understanding and explaining the process and mechanism of apoptosis in MSCs.

Chen, Tie-Long; Zhu, Guang-Li; Wang, Jian-An; Wang, Yu; He, Xiao-Long; Jiang, Jun

2014-01-01

94

Asthma Is Associated with Multiple Alterations in Anti-Viral Innate Signalling Pathways  

PubMed Central

Background Human rhinovirus (HRV) infection is a major trigger for asthma exacerbations. Anti-viral immunity appears to be abnormal in asthma, with immune dysfunction reported in both airway structural cells and migratory, bone marrow derived cells. Though decreased capacity to produce anti-viral interferons (IFNs) has been reported in asthma, a detailed analysis of the molecular events involved has not been undertaken. Objective To compare the molecular pathway controlling type I IFN synthesis in HRV-stimulated peripheral blood mononuclear cells (PBMC) from asthmatic and healthy subjects. Methods PBMC from 22 allergic asthmatics and 20 healthy donors were cultured with HRV for 24 hours. Multiple components of the Toll-like receptor (TLR), IFN regulatory and NF?? pathways were compared at the mRNA and protein level. Results Multiple deficiencies in the innate immune response to HRV were identified in asthma, with significantly lower expression of IFN?, IFN? and interferon stimulated genes than in healthy subjects. This was accompanied by reduced expression of intra-cellular signalling molecules including interferon regulatory factors (IRF1, IRF7), NF-?B family members (p50, p52, p65 and I?K?) and STAT1, and by reduced responsiveness to TLR7/TLR8 activation. These observations could not be attributed to alterations in the numbers of dendritic cell (DC) subsets in asthma or baseline expression of the viral RNA sensing receptors TLR7/TLR8. In healthy subjects, blocking the activity of type-I IFN or depleting plasmacytoid DC recapitulated many of the abnormalities observed in asthma. Conclusions Multiple abnormalities in innate anti-viral signalling pathways were identified in asthma, with deficiencies in both IFN-dependent and IFN-independent molecules identified. PMID:25203745

Pritchard, Antonia L.; White, Olivia J.; Burel, Julie G.; Carroll, Melanie L.; Phipps, Simon; Upham, John W.

2014-01-01

95

Suppressed RNA-polymerase 1 pathway is associated with benign multiple sclerosis.  

PubMed

Benign multiple sclerosis (BMS) occurs in about 15% of patients with relapsing-remitting multiple sclerosis (RRMS) that over time do not develop significant neurological disability. The molecular events associated with BMS are not clearly understood. This study sought to underlie the biological mechanisms associated with BMS. Blood samples obtained from a cohort of 31 patients with BMS and 36 patients with RRMS were applied for gene expression microarray analysis using HG-U133A-2 array (Affymetrix). Data were analyzed by Partek and pathway reconstruction was performed by Ingenuity for the most informative genes (MIGs). We identified a differing gene expression signature of 406 MIGs between BMS patients, mean±SE age 44.5±1.5 years, 24 females, 7 males, EDSS 1.9±0.2, disease duration 17.0±1.3 years, and RRMS patients, age 40.3±1.8 years, 24 females, 12 males, EDSS 3.5±0.2, disease duration 10.9±1.4 years. The signature was enriched by genes related RNA polymerase I (POL-1) transcription, general inflammatory response and activation of cell death. The most significant under-expressed pathway operating in BMS was the POL-1 pathway (p = 4.0*10(-5)) known while suppressed to activate P53 dependent apoptosis and to suppress NF?B induced inflammation. In accordance, of the 30 P53 target genes presented within the BMS signature, 19 had expression direction consistent with P53 activation. The transcripts within the pathway include POL-1 transcription factor 3 (RRN3, p = 4.8*10(-5)), POL-1 polypeptide D (POLR1D, p = 2.2*10(-4)), leucine-rich PPR-motif containing protein (LRPPRC p = 2.3*10(-5)), followed by suppression of the downstream family of ribosomal genes like RPL3, 6,13,22 and RPS6. In accordance POL-1 transcript and release factor PTRF that terminates POL-1 transcription, was over-expressed (p = 4.4*10(-3)). Verification of POL-1 pathway key genes was confirmed by qRT-PCR, and RRN3 silencing resulted in significant increase in the apoptosis level of PBMC sub-populations in RRMS patients. Our findings demonstrate that suppression of POL-1 pathway induce the low disease activity of BMS. PMID:23077530

Achiron, Anat; Feldman, Anna; Magalashvili, David; Dolev, Mark; Gurevich, Michael

2012-01-01

96

Rapid synthesis of auxin via a new tryptophan-dependent pathway is required for shade avoidance in plants  

PubMed Central

SUMMARY Plants grown at high densities perceive a decrease in the red to far-red (R:FR) ratio of incoming light, resulting from absorption of red light by canopy leaves and reflection of far-red light from neighboring plants. These changes in light quality trigger a series of responses known collectively as the shade avoidance syndrome. During shade avoidance, stems elongate at the expense of leaf and storage organ expansion, branching is inhibited, and flowering is accelerated. We identified several loci in Arabidopsis, mutations in which lead to plants defective in multiple shade avoidance outputs. Here we describe SAV3, an aminotransferase, and show that SAV3 catalyzes the formation of indole-3-pyruvic acid (IPA) from L-tryptophan (L-Trp), the first step in a previously proposed, but uncharacterized, auxin biosynthetic pathway. This pathway is rapidly deployed to biosynthesize auxin at the high levels required to initiate the multiple changes in body plan associated with shade avoidance. PMID:18394996

Tao, Yi; Ferrer, Jean-Luc; Ljung, Karin; Pojer, Florence; Hong, Fangxin; Long, Jeff A.; Li, Lin; Moreno, Javier E.; Bowman, Marianne E.; Ivans, Lauren J.; Cheng, Youfa; Lim, Jason; Zhao, Yunde; Ballaré, Carlos L.; Sandberg, Göran; Noel, Joseph P.; Chory, Joanne

2008-01-01

97

Associations between Proprioceptive Neural Pathway Structural Connectivity and Balance in People with Multiple Sclerosis  

PubMed Central

Mobility and balance impairments are a hallmark of multiple sclerosis (MS), affecting nearly half of patients at presentation and resulting in decreased activity and participation, falls, injuries, and reduced quality of life. A growing body of work suggests that balance impairments in people with mild MS are primarily the result of deficits in proprioception, the ability to determine body position in space in the absence of vision. A better understanding of the pathophysiology of balance disturbances in MS is needed to develop evidence-based rehabilitation approaches. The purpose of the current study was to (1) map the cortical proprioceptive pathway in vivo using diffusion-weighted imaging and (2) assess associations between proprioceptive pathway white matter microstructural integrity and performance on clinical and behavioral balance tasks. We hypothesized that people with MS (PwMS) would have reduced integrity of cerebral proprioceptive pathways, and that reduced white matter microstructure within these tracts would be strongly related to proprioceptive-based balance deficits. We found poorer balance control on proprioceptive-based tasks and reduced white matter microstructural integrity of the cortical proprioceptive tracts in PwMS compared with age-matched healthy controls (HC). Microstructural integrity of this pathway in the right hemisphere was also strongly associated with proprioceptive-based balance control in PwMS and controls. Conversely, while white matter integrity of the right hemisphere’s proprioceptive pathway was significantly correlated with overall balance performance in HC, there was no such relationship in PwMS. These results augment existing literature suggesting that balance control in PwMS may become more dependent upon (1) cerebellar-regulated proprioceptive control, (2) the vestibular system, and/or (3) the visual system. PMID:25368564

Fling, Brett W.; Dutta, Geetanjali Gera; Schlueter, Heather; Cameron, Michelle H.; Horak, Fay B.

2014-01-01

98

Multiple signalling pathways redundantly control glucose transporter GLUT4 gene transcription in skeletal muscle  

PubMed Central

Increased glucose transporter GLUT4 expression in skeletal muscle is an important benefit of regular exercise, resulting in improved insulin sensitivity and glucose tolerance. The Ca2+–calmodulin-dependent kinase II (CaMKII), calcineurin and AMPK pathways have been implicated in GLUT4 gene regulation based on pharmacological evidence. Here, we have used a more specific genetic approach to establish the relative role of the three pathways in fast and slow muscles. Plasmids coding for protein inhibitors of CaMKII or calcineurin were co-transfected in vivo with a GLUT4 enhancer-reporter construct either in normal mice or in mice expressing a kinase dead (KD) AMPK mutant. GLUT4 reporter activity was not inhibited in the slow soleus muscle by blocking either CaMKII or calcineurin alone, but was inhibited by blocking both pathways. GLUT4 reporter activity was likewise unchanged in the soleus of KD-AMPK mice, but was significantly reduced by incapacitation of either CaMKII or calcineurin in these mice. On the other hand, in the fast tibialis anterior (TA) muscle, calcineurin appears to exert a prominent role in the control of GLUT4 reporter activity, independent of CaMKII and AMPK. The results point to a muscle type-specific and redundant regulation of GLUT4 enhancer based on the interplay of multiple signalling pathways, all of which are known to affect myocyte enhancing factor 2 (MEF2) transcriptional activity, a point of convergence of different pathways on muscle gene regulation. PMID:19596898

Murgia, Marta; Jensen, Thomas E; Cusinato, Marzia; Garcia, Marta; Richter, Erik A; Schiaffino, Stefano

2009-01-01

99

The Toll pathway is required in the epidermis for muscle development in the Drosophila embryo  

NASA Technical Reports Server (NTRS)

The Toll signaling pathway functions in several Drosophila processes, including dorsal-ventral pattern formation and the immune response. Here, we demonstrate that this pathway is required in the epidermis for proper muscle development. Previously, we showed that the zygotic Toll protein is necessary for normal muscle development; in the absence of zygotic Toll, close to 50% of hemisegments have muscle patterning defects consisting of missing, duplicated and misinserted muscle fibers (Halfon, M.S., Hashimoto, C., and Keshishian, H., Dev. Biol. 169, 151-167, 1995). We have now also analyzed the requirements for easter, spatzle, tube, and pelle, all of which function in the Toll-mediated dorsal-ventral patterning pathway. We find that spatzle, tube, and pelle, but not easter, are necessary for muscle development. Mutations in these genes give a phenotype identical to that seen in Toll mutants, suggesting that elements of the same pathway used for Toll signaling in dorsal-ventral development are used during muscle development. By expressing the Toll cDNA under the control of distinct Toll enhancer elements in Toll mutant flies, we have examined the spatial requirements for Toll expression during muscle development. Expression of Toll in a subset of epidermal cells that includes the epidermal muscle attachment cells, but not Toll expression in the musculature, is necessary for proper muscle development. Our results suggest that signals received by the epidermis early during muscle development are an important part of the muscle patterning process.

Halfon, M. S.; Keshishian, H.

1998-01-01

100

APL-1, the Alzheimer’s Amyloid Precursor Protein in Caenorhabditis elegans, Modulates Multiple Metabolic Pathways Throughout Development  

PubMed Central

Mutations in the amyloid precursor protein (APP) gene or in genes that process APP are correlated with familial Alzheimer’s disease (AD). The biological function of APP remains unclear. APP is a transmembrane protein that can be sequentially cleaved by different secretases to yield multiple fragments, which can potentially act as signaling molecules. Caenorhabditis elegans encodes one APP-related protein, APL-1, which is essential for viability. Here, we show that APL-1 signaling is dependent on the activity of the FOXO transcription factor DAF-16 and the nuclear hormone receptor DAF-12 and influences metabolic pathways such as developmental progression, body size, and egg-laying rate. Furthermore, apl-1(yn5) mutants, which produce high levels of the extracellular APL-1 fragment, show an incompletely penetrant temperature-sensitive embryonic lethality. In a genetic screen to isolate mutants in which the apl-1(yn5) lethality rate is modified, we identified a suppressor mutation in MOA-1/R155.2, a receptor-protein tyrosine phosphatase, and an enhancer mutation in MOA-2/B0495.6, a protein involved in receptor-mediated endocytosis. Knockdown of apl-1 in an apl-1(yn5) background caused lethality and molting defects at all larval stages, suggesting that apl-1 is required for each transitional molt. We suggest that signaling of the released APL-1 fragment modulates multiple metabolic states and that APL-1 is required throughout development. PMID:22466039

Ewald, Collin Y.; Raps, Daniel A.; Li, Chris

2012-01-01

101

Multiple motor pathways to single smooth muscle cells in the ferret trachea.  

PubMed

1. We investigated the distribution and characteristics of motor pathways to individual smooth muscle cells activated by electrical stimulation of either, single nerves which enter the tracheal plexus (inlet nerves), or a longitudinal nerve trunk (LNT) located near the entrance of an inlet nerve into the plexus. Excitatory junction potentials (EJPs) were recorded using intracellular microelectrodes as an index of smooth muscle cell activation. In all experiments EJPs were completely blocked by tetrodotoxin and by atropine. 2. In smooth muscle fields located in the caudal direction from the point of inlet or LNT nerve stimulation, neural input decreased as a function of distance. There was evidence of a demarcated area innervated by neurons entering the plexus in one inlet nerve. In smooth muscle fields located in the rostral or transverse direction from the site of nerve stimulation, no such demarcated area could be identified. 3. Of the smooth muscle cells located within the innervated fields studied, 83-95% were activated following stimulation of a single inlet nerve or LNT. Evoked EJPs were similar in different innervated cells or units of electrically coupled cells located within the same 1 mm2 'field'. 4. There was overlapping cholinergic motor input to single smooth muscle cells originating from neurons present in different inlet nerves or different neurons present in the same inlet nerve or region of the LNT. Multiple small step increases in the voltage used to stimulate a LNT resulted in three or four step increases in EJP amplitudes. This gives a minimal value for the number of motor pathways that can be activated by neurons in a region of LNT leading to a single smooth muscle cell. 5. Motor pathways to smooth muscle cells located in caudal and rostral fields ran initially in the LNT and exited in proximity to the smooth muscle cell studied. 6. Motor pathways used in transmitting signals to smooth muscle cells to different areas of trachealis muscle varied in their sensitivity to hexamethonium or curare. EJPs evoked in fields located in the caudal direction from the stimulating electrode were abolished by these drugs. Muscle cells located in different rostral fields showed EJPs that were either sensitive or resistant to these drugs. 7. The rostral hexamethonium-resistant pathway ran initially in the LNT but it exited from the LNT several millimetres before reaching the level of the smooth muscle field innervated. This pathway followed stimulation frequencies up to 25 Hz. The final neuron in this pathway released acetylcholine and evoked EJPs were entirely inhibited by atropine.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:1293288

Mitchell, H W; Coburn, R F

1992-10-01

102

Arabidopsis CAND1, an Unmodified CUL1-Interacting Protein, Is Involved in Multiple Developmental Pathways Controlled  

E-print Network

Arabidopsis CAND1, an Unmodified CUL1-Interacting Protein, Is Involved in Multiple Developmental-associated and neddylation-dissociated) and demonstrate that it can preferentially interact with unmodified CUL1 activity of CUL1-containing ubiquitin E3 ligases, indicating that CAND1 is required for their optimal

Deng, Xing-Wang

103

Simultaneous Reconstruction of Multiple Signaling Pathways via the Prize-Collecting Steiner Forest Problem  

PubMed Central

Abstract Signaling and regulatory networks are essential for cells to control processes such as growth, differentiation, and response to stimuli. Although many “omic” data sources are available to probe signaling pathways, these data are typically sparse and noisy. Thus, it has been difficult to use these data to discover the cause of the diseases and to propose new therapeutic strategies. We overcome these problems and use “omic” data to reconstruct simultaneously multiple pathways that are altered in a particular condition by solving the prize-collecting Steiner forest problem. To evaluate this approach, we use the well-characterized yeast pheromone response. We then apply the method to human glioblastoma data, searching for a forest of trees, each of which is rooted in a different cell-surface receptor. This approach discovers both overlapping and independent signaling pathways that are enriched in functionally and clinically relevant proteins, which could provide the basis for new therapeutic strategies. Although the algorithm was not provided with any information about the phosphorylation status of receptors, it identifies a small set of clinically relevant receptors among hundreds present in the interactome. PMID:23383998

Tuncbag, Nurcan; Braunstein, Alfredo; Pagnani, Andrea; Huang, Shao-Shan Carol; Chayes, Jennifer; Borgs, Christian; Zecchina, Riccardo

2013-01-01

104

miR-221 affects multiple cancer pathways by modulating the level of hundreds messenger RNAs  

PubMed Central

microRNA miR-221 is frequently over-expressed in a variety of human neoplasms. Aim of this study was to identify new miR-221 gene targets to improve our understanding on the molecular tumor-promoting mechanisms affected by miR-221. Gene expression profiling of miR-221-transfected-SNU-398 cells was analyzed by the Sylamer algorithm to verify the enrichment of miR-221 targets among down-modulated genes. This analysis revealed that enforced expression of miR-221 in SNU-398 cells caused the down-regulation of 602 mRNAs carrying sequences homologous to miR-221 seed sequence within their 3?UTRs. Pathways analysis performed on these genes revealed their prominent involvement in cell proliferation and apoptosis. Activation of E2F, MYC, NFkB, and ?-catenin pathways was experimentally proven. Some of the new miR-221 target genes, including RB1, WEE1 (cell cycle inhibitors), APAF1 (pro-apoptotic), ANXA1, CTCF (transcriptional repressor), were individually validated as miR-221 targets in SNU-398, HepG2, and HEK293 cell lines. By identifying a large set of miR-221 gene targets, this study improves our knowledge about miR-221 molecular mechanisms involved in tumorigenesis. The modulation of mRNA level of 602 genes confirms the ability of miR-221 to promote cancer by affecting multiple oncogenic pathways. PMID:23630541

Lupini, Laura; Bassi, Cristian; Ferracin, Manuela; Bartonicek, Nenad; D'Abundo, Lucilla; Zagatti, Barbara; Callegari, Elisa; Musa, Gentian; Moshiri, Farzaneh; Gramantieri, Laura; Corrales, Fernando J.; Enright, Anton J.; Sabbioni, Silvia; Negrini, Massimo

2013-01-01

105

Genistein inhibits tumor invasion by suppressing multiple signal transduction pathways in human hepatocellular carcinoma cells  

PubMed Central

Background Genistein (Gen) exhibits anti-mutagenic and anti-metastatic activities in hepatoma cell lines. Gen has suppressive effects on tumor growth and angiogenesis in nude mice. Gen suppresses the enzymatic activity of matrix metalloproteinase (MMP)-9; however, the mechanism underlying its anti-invasive activity on hepatocellular carcinoma (HCC) cells is unclear. Methods In this study, the possible mechanisms underlying Gen-mediated reduction of 12-O-Tetradecanoylphorbol-13-acetate (TPA)-induced cell invasion and inhibition of secreted and cytosolic MMP-9 production in human hepatoma cells (HepG2, Huh-7, and HA22T) and murine embryonic liver cells (BNL CL2) were investigated. Results Gen suppressed MMP-9 transcription by inhibiting activator protein (AP)-1 and nuclear factor-? B (NF-?B) activity. Gen suppressed TPA-induced AP-1 activity through inhibitory phosphorylation of extracellular signal-related kinase (ERK) and c-Jun N-terminal kinase (JNK) signaling pathways, and TPA-stimulated inhibition of NF-?B nuclear translocation through I?B inhibitory signaling pathways. Moreover, Gen suppressed TPA-induced activation of ERK/phosphatidylinositol 3-kinase/Akt upstream of NF-?B and AP-1. Conclusions Gen and its inhibition of multiple signal transduction pathways can control the invasiveness and metastatic potential of HCC. PMID:24433534

2014-01-01

106

Targeting TopBP1 at a convergent point of multiple oncogenic pathways for cancer therapy.  

PubMed

The progression of many solid tumours is driven by deregulation of multiple common pathways, particularly Rb, PI(3)K/Akt and p53. Prior studies identified TopBP1 as a key mediator for the oncogenic gain-of-function activities of mutant p53 (mutp53) in cancer. In Akt-hyperactive cancer, TopBP1 forms oligomers and represses E2F1-dependent apoptosis. Here we perform a molecular docking screening and identify a lead compound, calcein, capable of blocking TopBP1 oligomerization and p53 binding, resulting in re-activation of E2F1-dependent apoptosis and blockade of mutp53 gain-of-function. Calcein AM, the cell-permeable derivative of calcein, shows significant antitumour activity in a wide spectrum of cultured cancer cells harbouring high TopBP1 levels. These biochemical findings are recapitulated in breast cancer xenograft models. Thus, our study provides proof-of-concept evidence for targeting TopBP1, a convergent point of multiple pathways, as a cancer therapy. PMID:25400145

Chowdhury, Pinki; Lin, Gregory E; Liu, Kang; Song, Yongcheng; Lin, Fang-Tsyr; Lin, Weei-Chin

2014-01-01

107

Beclin 1 is required for neuron viability and regulates endosome pathways via the UVRAG-VPS34 complex.  

PubMed

Deficiency of autophagy protein beclin 1 is implicated in tumorigenesis and neurodegenerative diseases, but the molecular mechanism remains elusive. Previous studies showed that Beclin 1 coordinates the assembly of multiple VPS34 complexes whose distinct phosphatidylinositol 3-kinase III (PI3K-III) lipid kinase activities regulate autophagy at different steps. Recent evidence suggests a function of beclin 1 in regulating multiple VPS34-mediated trafficking pathways beyond autophagy; however, the precise role of beclin 1 in autophagy-independent cellular functions remains poorly understood. Herein we report that beclin 1 regulates endocytosis, in addition to autophagy, and is required for neuron viability in vivo. We find that neuronal beclin 1 associates with endosomes and regulates EEA1/early endosome localization and late endosome formation. Beclin 1 maintains proper cellular phosphatidylinositol 3-phosphate (PI(3)P) distribution and total levels, and loss of beclin 1 causes a disruption of active Rab5 GTPase-associated endosome formation and impairment of endosome maturation, likely due to a failure of Rab5 to recruit VPS34. Furthermore, we find that Beclin 1 deficiency causes complete loss of the UVRAG-VPS34 complex and associated lipid kinase activity. Interestingly, beclin 1 deficiency impairs p40phox-linked endosome formation, which is rescued by overexpressed UVRAG or beclin 1, but not by a coiled-coil domain-truncated beclin 1 (a UVRAG-binding mutant), Atg14L or RUBICON. Thus, our study reveals the essential role for beclin 1 in neuron survival involving multiple membrane trafficking pathways including endocytosis and autophagy, and suggests that the UVRAG-beclin 1 interaction underlies beclin 1's function in endocytosis. PMID:25275521

McKnight, Nicole C; Zhong, Yun; Wold, Mitchell S; Gong, Shiaoching; Phillips, Greg R; Dou, Zhixun; Zhao, Yanxiang; Heintz, Nathaniel; Zong, Wei-Xing; Yue, Zhenyu

2014-10-01

108

Beclin 1 Is Required for Neuron Viability and Regulates Endosome Pathways via the UVRAG-VPS34 Complex  

PubMed Central

Deficiency of autophagy protein beclin 1 is implicated in tumorigenesis and neurodegenerative diseases, but the molecular mechanism remains elusive. Previous studies showed that Beclin 1 coordinates the assembly of multiple VPS34 complexes whose distinct phosphatidylinositol 3-kinase III (PI3K-III) lipid kinase activities regulate autophagy at different steps. Recent evidence suggests a function of beclin 1 in regulating multiple VPS34-mediated trafficking pathways beyond autophagy; however, the precise role of beclin 1 in autophagy-independent cellular functions remains poorly understood. Herein we report that beclin 1 regulates endocytosis, in addition to autophagy, and is required for neuron viability in vivo. We find that neuronal beclin 1 associates with endosomes and regulates EEA1/early endosome localization and late endosome formation. Beclin 1 maintains proper cellular phosphatidylinositol 3-phosphate (PI(3)P) distribution and total levels, and loss of beclin 1 causes a disruption of active Rab5 GTPase-associated endosome formation and impairment of endosome maturation, likely due to a failure of Rab5 to recruit VPS34. Furthermore, we find that Beclin 1 deficiency causes complete loss of the UVRAG-VPS34 complex and associated lipid kinase activity. Interestingly, beclin 1 deficiency impairs p40phox-linked endosome formation, which is rescued by overexpressed UVRAG or beclin 1, but not by a coiled-coil domain-truncated beclin 1 (a UVRAG-binding mutant), Atg14L or RUBICON. Thus, our study reveals the essential role for beclin 1 in neuron survival involving multiple membrane trafficking pathways including endocytosis and autophagy, and suggests that the UVRAG-beclin 1 interaction underlies beclin 1's function in endocytosis. PMID:25275521

Wold, Mitchell S.; Gong, Shiaoching; Phillips, Greg R.; Dou, Zhixun; Zhao, Yanxiang; Heintz, Nathaniel; Zong, Wei-Xing; Yue, Zhenyu

2014-01-01

109

A novel component of the disulfide-reducing pathway required for cytochrome c assembly in plastids.  

PubMed

In plastids, the conversion of energy in the form of light to ATP requires key electron shuttles, the c-type cytochromes, which are defined by the covalent attachment of heme to a CXXCH motif. Plastid c-type cytochrome biogenesis occurs in the thylakoid lumen and requires a system for transmembrane transfer of reductants. Previously, CCDA and CCS5/HCF164, found in all plastid-containing organisms, have been proposed as two components of the disulfide-reducing pathway. In this work, we identify a small novel protein, CCS4, as a third component in this pathway. CCS4 was genetically identified in the green alga Chlamydomonas reinhardtii on the basis of the rescue of the ccs4 mutant, which is blocked in the synthesis of holoforms of plastid c-type cytochromes, namely cytochromes f and c(6). Although CCS4 does not display sequence motifs suggestive of redox or heme-binding function, biochemical and genetic complementation experiments suggest a role in the disulfide-reducing pathway required for heme attachment to apoforms of cytochromes c. Exogenous thiols partially rescue the growth phenotype of the ccs4 mutant concomitant with recovery of holocytochrome f accumulation, as does expression of an ectopic copy of the CCDA gene, encoding a trans-thylakoid transporter of reducing equivalents. We suggest that CCS4 might function to stabilize CCDA or regulate its activity. PMID:21220358

Gabilly, Stéphane T; Kropat, Janette; Karamoko, Mohamed; Page, M Dudley; Nakamoto, Stacie S; Merchant, Sabeeha S; Hamel, Patrice P

2011-03-01

110

The hangover gene defines a stress pathway required for ethanol tolerance development  

PubMed Central

Repeated alcohol consumption leads to the development of tolerance, simply defined as an acquired resistance to the physiological and behavioral effects of the drug. This tolerance allows increased alcohol consumption, which over time leads to physical dependence and possibly addiction1–3. Previous studies showed that Drosophila develop ethanol tolerance with kinetics of acquisition and dissipation that mimic those seen in mammals. This tolerance requires the catecholamine octopamine, the functional analog of mammalian noradrenaline4. Here we describe a novel gene, hangover, required for normal development of ethanol tolerance. hangover flies are also defective in responses to environmental stressors, such as heat and the free radical-generating agent paraquat. Using genetic epistasis tests we show that ethanol tolerance in Drosophila relies on two distinct molecular pathways, a cellular stress pathway defined by hangover and a parallel pathway requiring octopamine. hangover encodes a large nuclear zinc-finger protein suggesting a role in nucleic acid binding. There is growing recognition that stress, at the cellular and systemic levels, contributes to drug- and addiction-related behaviors in mammals. Our studies suggest that this role may be conserved in evolution. PMID:16094367

Scholz, Henrike; Franz, Mirjam; Heberlein, Ulrike

2005-01-01

111

Ursolic acid inhibits colorectal cancer angiogenesis through suppression of multiple signaling pathways.  

PubMed

Angiogenesis plays a critical role in the development of solid tumors by supplying nutrients and oxygen to support continuous growth of tumor as well as providing an avenue for hematogenous metastasis. Tumor angiogenesis is highly regulated by multiple intracellular signaling transduction cascades such as Hedgehog, STAT3, Akt and p70S6K pathways that are known to malfunction in many types of cancer including colorectal cancer (CRC). Therefore, suppression of tumor angiogenesis through targeting these signaling pathways has become a promising strategy for cancer chemotherapy. Ursolic acid (UA) is a major active compound present in many medicinal herbs that have long been used in China for the clinical treatment of various types of cancer. Although previous studies have demonstrated an antitumor effect for UA, the precise mechanisms of its anti-angiogenic activity are not well understood. To further elucidate the mechanism(s) of the tumorcidal activity of UA, using a CRC mouse xenograft model, chick embryo chorioallantoic membrane (CAM) model, the human colon carcinoma cell line HT-29 and human umbilical vein endothelial cells (HUVECs), in the present study we evaluated the efficacy of UA against tumor growth and angiogenesis in vivo and in vitro and investigated the underlying molecular mechanisms. We found that administration of UA significantly inhibited tumor volume but had no effect on body weight changes in CRC mice, suggesting that UA can suppress colon cancer growth in vivo without noticeable signs of toxicity. In addition, UA treatment reduced intratumoral microvessel density (MVD) in CRC mice, decreased the total number of blood vessels in the CAM model, and dose and time-dependently inhibited the proliferation, migration and tube formation of HUVECs, demonstrating UA's antitumor angiogenesis in vivo and in vitro. Moreover, UA treatment inhibited the expression of critical angiogenic factors, such as VEGF-A and bFGF. Furthermore, UA suppressed the activation of sonic hedgehog (SHH), STAT3, Akt and p70S6K pathways. Collectively, our findings suggest that inhibition of tumor angiogenesis via suppression of multiple signaling pathways might be one of the mechanisms whereby UA can be effective in cancer treatment. PMID:24042330

Lin, Jiumao; Chen, Youqin; Wei, Lihui; Hong, Zhenfeng; Sferra, Thomas J; Peng, Jun

2013-11-01

112

Smoldering multiple myeloma requiring treatment: time for a new definition?  

PubMed Central

Smoldering multiple myeloma (SMM) bridges the gap between monoclonal gammopathy of undetermined significance (a mostly premalignant disorder) and active multiple myeloma (MM). Until recently, no interventional study in patients with SMM showed improved overall survival (OS) with therapy as compared with observation. A report from the PETHEMA-GEM (Programa Español de Tratamientos en Hematologica) group described both fewer myeloma-related events and better OS among patients with high-risk SMM who were treated with lenalidomide and dexamethasone. This unique study prompted us to review current knowledge about SMM and address the following questions: (1) Are there patients currently defined as SMM who should be treated routinely? (2) Should the definitions of SMM and MM be reconsidered? (3) Has the time come when not treating is more dangerous than treating? (4) Could unintended medical harm result from overzealous intervention? Our conclusion is that those patients with the highest-risk SMM (extreme bone marrow plasmacytosis, extremely abnormal serum immunoglobulin free light chain ratio, and multiple bone lesions detected only by modern imaging) should be reclassified as active MM so that they can receive MM-appropriate therapy and the paradigm of careful observation for patients with SMM can be preserved. PMID:24144641

Stewart, A. Keith; Chanan-Khan, Asher; Rajkumar, S. Vincent; Kyle, Robert A.; Fonseca, Rafael; Kapoor, Prashant; Bergsagel, P. Leif; McCurdy, Arleigh; Gertz, Morie A.; Lacy, Martha Q.; Lust, John A.; Russell, Stephen J.; Zeldenrust, Steven R.; Reeder, Craig; Roy, Vivek; Buadi, Francis; Dingli, David; Hayman, Suzanne R.; Leung, Nelson; Lin, Yi; Mikhael, Joseph; Kumar, Shaji K.

2013-01-01

113

Smoldering multiple myeloma requiring treatment: time for a new definition?  

PubMed

Smoldering multiple myeloma (SMM) bridges the gap between monoclonal gammopathy of undetermined significance (a mostly premalignant disorder) and active multiple myeloma (MM). Until recently, no interventional study in patients with SMM showed improved overall survival (OS) with therapy as compared with observation. A report from the PETHEMA-GEM (Programa Español de Tratamientos en Hematologica) group described both fewer myeloma-related events and better OS among patients with high-risk SMM who were treated with lenalidomide and dexamethasone. This unique study prompted us to review current knowledge about SMM and address the following questions: (1) Are there patients currently defined as SMM who should be treated routinely? (2) Should the definitions of SMM and MM be reconsidered? (3) Has the time come when not treating is more dangerous than treating? (4) Could unintended medical harm result from overzealous intervention? Our conclusion is that those patients with the highest-risk SMM (extreme bone marrow plasmacytosis, extremely abnormal serum immunoglobulin free light chain ratio, and multiple bone lesions detected only by modern imaging) should be reclassified as active MM so that they can receive MM-appropriate therapy and the paradigm of careful observation for patients with SMM can be preserved. PMID:24144641

Dispenzieri, Angela; Stewart, A Keith; Chanan-Khan, Asher; Rajkumar, S Vincent; Kyle, Robert A; Fonseca, Rafael; Kapoor, Prashant; Bergsagel, P Leif; McCurdy, Arleigh; Gertz, Morie A; Lacy, Martha Q; Lust, John A; Russell, Stephen J; Zeldenrust, Steven R; Reeder, Craig; Roy, Vivek; Buadi, Francis; Dingli, David; Hayman, Suzanne R; Leung, Nelson; Lin, Yi; Mikhael, Joseph; Kumar, Shaji K

2013-12-19

114

Fibroblast activation protein protects bortezomib-induced apoptosis in multiple myeloma cells through ?-catenin signaling pathway.  

PubMed

Multiple myeloma (MM) is a malignant plasma cells proliferative disease. The intricate cross-talk of myeloma cells with bone marrow microenvironment plays an important role in facilitating growth and survival of myeloma cells. Bone marrow mesenchymal stem cells (BMMSCs) are important cells in MM microenvironment. In solid tumors, BMMSCs can be educated by tumor cells to become cancer-associated fibroblasts (CAFs) with high expression of fibroblast activation protein (FAP). FAP was reported to be involved in drug resistance, tumorigenesis, neoplastic progression, angiogenesis, invasion, and metastasis of tumor cells. However, the expression and the role of FAP in MM bone marrow microenvironment are still less known. The present study is aimed to investigate the expression of FAP, the role of FAP, and its relevant signaling pathway in regulating apoptosis induced by bortezomib in MM cells. In this study, our data illustrated that the expression levels of FAP were not different between the cultured BMMSCs isolated from MM patients and normal donors. The expression levels of FAP can be increased by tumor cells conditioned medium (TCCM) stimulation or coculture with RPMI8226 cells. FAP has important role in BMMSCs mediated protecting MM cell lines from apoptosis induced by bortezomib. Further study showed that this process may likely through ?-catenin signaling pathway in vitro. The activation of ?-catenin in MM cell lines was dependent on direct contact with BMMSCs other than separated by transwell or additional condition medium from BMMSCs and cytokines. PMID:25046247

Zi, Fu-Ming; He, Jing-Song; Li, Yi; Wu, Cai; Wu, Wen-Jun; Yang, Yang; Wang, Li-Juan; He, Dong-Hua; Yang, Li; Zhao, Yi; Zheng, Gao-Feng; Han, Xiao-Yan; Huang, He; Yi, Qing; Cai, Zhen

2014-10-01

115

Angiogenic activity of sesamin through the activation of multiple signal pathways  

SciTech Connect

The natural product sesamin has been known to act as a potent antioxidant and prevent endothelial dysfunction. We here found that sesamin increased in vitro angiogenic processes, such as endothelial cell proliferation, migration, and tube formation, as well as neovascularization in an animal model. This compound elicited the activation of multiple angiogenic signal modulators, such as ERK, Akt, endothelial nitric oxide synthase (eNOS), NO production, FAK, and p38 MAPK, but not Src. The MEK inhibitor PD98059 and the PI3K inhibitor Wortmannin specifically inhibited sesamin-induced activation of the ERK and Akt/eNOS pathways. These inhibitors reduced angiogenic events, with high specificity for MEK/ERK-dependent cell proliferation and migration and PI3K/Akt-mediated tube formation. Moreover, inhibition of p38 MAPK effectively inhibited sesamin-induced cell migration. The angiogenic activity of sesamin was not associated with VEGF expression. Furthermore, this compound did not induce vascular permeability and upregulated ICAM-1 and VCAM-1 expression, which are hallmarks of vascular inflammation. These results suggest that sesamin stimulates angiogenesis in vitro and in vivo through the activation of MEK/ERK-, PI3K/Akt/eNOS-, p125{sup FAK}-, and p38 MAPK-dependent pathways, without increasing vascular inflammation, and may be used for treating ischemic diseases and tissue regeneration.

Chung, Byung-Hee [Vascular System Research Center and Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon (Korea, Republic of) [Vascular System Research Center and Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon (Korea, Republic of); Division of Food Biotechnology, School of Biotechnology, Kangwon National University, Chuncheon (Korea, Republic of); Lee, Jung Joon [Center for Molecular Cancer Research, Korea Research Institute of Bioscience and Biotechnology, Daejeon (Korea, Republic of)] [Center for Molecular Cancer Research, Korea Research Institute of Bioscience and Biotechnology, Daejeon (Korea, Republic of); Kim, Jong-Dai [Division of Food Biotechnology, School of Biotechnology, Kangwon National University, Chuncheon (Korea, Republic of)] [Division of Food Biotechnology, School of Biotechnology, Kangwon National University, Chuncheon (Korea, Republic of); Jeoung, Dooil; Lee, Hansoo [Division of Life Sciences, Kangwon National University, Chuncheon (Korea, Republic of)] [Division of Life Sciences, Kangwon National University, Chuncheon (Korea, Republic of); Choe, Jongseon; Ha, Kwon-Soo [Vascular System Research Center and Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon (Korea, Republic of)] [Vascular System Research Center and Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon (Korea, Republic of); Kwon, Young-Geun [Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul (Korea, Republic of)] [Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul (Korea, Republic of); Kim, Young-Myeong, E-mail: ymkim@kangwon.ac.kr [Vascular System Research Center and Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon (Korea, Republic of)] [Vascular System Research Center and Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon (Korea, Republic of)

2010-01-01

116

Select spinal lesions reveal multiple ascending pathways in the rat conveying input from the male genitalia  

PubMed Central

The specific white matter location of all the spinal pathways conveying penile input to the rostral medulla is not known. Our previous studies using rats demonstrated the loss of low but not high threshold penile inputs to medullary reticular formation (MRF) neurons after acute and chronic dorsal column (DC) lesions of the T8 spinal cord and loss of all penile inputs after lesioning the dorsal three-fifths of the cord. In the present study, select T8 lesions were made and terminal electrophysiological recordings were performed 45–60 days later in a limited portion of the nucleus reticularis gigantocellularis (Gi) and Gi pars alpha. Lesions included subtotal dorsal hemisections that spared only the lateral half of the dorsal portion of the lateral funiculus on one side, dorsal and over-dorsal hemisections, and subtotal transections that spared predominantly just the ventromedial white matter. Electrophysiological data for 448 single unit recordings obtained from 32 urethane-anaesthetized rats, when analysed in groups based upon histological lesion reconstructions, revealed (1) ascending bilateral projections in the dorsal, dorsolateral and ventrolateral white matter of the spinal cord conveying information from the male external genitalia to MRF, and (2) ascending bilateral projections in the ventrolateral white matter conveying information from the pelvic visceral organs (bladder, descending colon, urethra) to MRF. Multiple spinal pathways from the penis to the MRF may correspond to different functions, including those processing affective/pleasure/motivational, nociception, and mating-specific (such as for erection and ejaculation) inputs. PMID:20142271

Hubscher, C H; Reed, W R; Kaddumi, E G; Armstrong, J E; Johnson, R D

2010-01-01

117

The Major Cellular Sterol Regulatory Pathway Is Required for Andes Virus Infection  

PubMed Central

The Bunyaviridae comprise a large family of RNA viruses with worldwide distribution and includes the pathogenic New World hantavirus, Andes virus (ANDV). Host factors needed for hantavirus entry remain largely enigmatic and therapeutics are unavailable. To identify cellular requirements for ANDV infection, we performed two parallel genetic screens. Analysis of a large library of insertionally mutagenized human haploid cells and a siRNA genomic screen converged on components (SREBP-2, SCAP, S1P and S2P) of the sterol regulatory pathway as critically important for infection by ANDV. The significance of this pathway was confirmed using functionally deficient cells, TALEN-mediated gene disruption, RNA interference and pharmacologic inhibition. Disruption of sterol regulatory complex function impaired ANDV internalization without affecting virus binding. Pharmacologic manipulation of cholesterol levels demonstrated that ANDV entry is sensitive to changes in cellular cholesterol and raises the possibility that clinically approved regulators of sterol synthesis may prove useful for combating ANDV infection. PMID:24516383

Riblett, Amber M.; Didigu, Chukwuka A.; Wilen, Craig B.; Malani, Nirav; Male, Frances; Lee, Fang-Hua; Bushman, Frederic D.; Cherry, Sara; Doms, Robert W.; Bates, Paul; Briley, Kenneth

2014-01-01

118

Family Histories and Multiple Transitions Among Homeless Young Adults: Pathways to Homelessness  

PubMed Central

This study explored the early family histories of homeless young adults, the types and number of transitions they experienced, and their pathways to the street. Intensive qualitative interviews were audio taped and transcribed with 40 homeless young adults 19 to 21 years of age in the Midwest. Findings show that family backgrounds were generally characterized by substance use, child maltreatment, and witnessing violence, all of which provide social context for understanding why so many of these young people opted to leave home in search of an alternative living situation. The current findings also reveal that while some young adults ran away from home as adolescents, others were “pushed out” (i.e., told to leave), or removed by state agencies. Current study findings illustrate that young adults’ trajectories are marked by multiple living arrangements such as home, foster care, detention facility, and drug rehabilitation. Overall, study results show that young adults’ family histories place them on trajectories for early independence marked by multiple transitions and numerous living situations, culminating in a lack of a permanent residence to call home. PMID:24151346

Tyler, Kimberly A.; Schmitz, Rachel M.

2013-01-01

119

Aryl hydrocarbon receptor knock-out exacerbates choroidal neovascularization via multiple pathogenic pathways  

PubMed Central

The aryl hydrocarbon receptor (AhR) is a heterodimeric transcriptional regulator with pleiotropic functions in xenobiotic metabolism and detoxification, vascular development and cancer. Herein, we report a previously undescribed role for the AhR signalling pathway in the pathogenesis of the wet, neovascular subtype of age-related macular degeneration (AMD), the leading cause of vision loss in the elderly in the Western world. Comparative analysis of gene expression profiles of aged AhR?/? and wild-type (wt) mice, using high-throughput RNA sequencing, revealed differential modulation of genes belonging to several AMD-related pathogenic pathways, including inflammation, angiogenesis and extracellular matrix regulation. To investigate AhR regulation of these pathways in wet AMD, we experimentally induced choroidal neovascular lesions in AhR?/? mice and found that they measured significantly larger in area and volume compared to age-matched wt mice. Furthermore, these lesions displayed a higher number of ionized calcium-binding adaptor molecule 1-positive (Iba1+) microglial cells and a greater amount of collagen type IV deposition, events also seen in human wet AMD pathology specimens. Consistent with our in vivo observations, AhR knock-down was sufficient to increase choroidal endothelial cell migration and tube formation in vitro. Moreover, AhR knock-down caused an increase in collagen type IV production and secretion in both retinal pigment epithelial (RPE) and choroidal endothelial cell cultures, increased expression of angiogenic and inflammatory molecules, including vascular endothelial growth factor A (VEGFA) and chemokine (C–C motif) ligand 2 (CCL2) in RPE cells, and increased expression of secreted phosphoprotein 1 (SPP1) and transforming growth factor-?1 (TGF?1) in choroidal endothelial cells. Collectively, our findings identify AhR as a regulator of multiple pathogenic pathways in experimentally induced choroidal neovascularization, findings that are consistent with a possible role of AhR in wet AMD. The data discussed in this paper have been deposited in NCBI's Gene Expression Omnibus; GEO Submission No. GSE56983, NCBI Tracking System No. 17021116. PMID:25186463

Choudhary, Mayur; Kazmin, Dmitri; Hu, Peng; Thomas, Russell S; McDonnell, Donald P; Malek, Goldis

2015-01-01

120

Aryl hydrocarbon receptor knock-out exacerbates choroidal neovascularization via multiple pathogenic pathways.  

PubMed

The aryl hydrocarbon receptor (AhR) is a heterodimeric transcriptional regulator with pleiotropic functions in xenobiotic metabolism and detoxification, vascular development and cancer. Herein, we report a previously undescribed role for the AhR signalling pathway in the pathogenesis of the wet, neovascular subtype of age-related macular degeneration (AMD), the leading cause of vision loss in the elderly in the Western world. Comparative analysis of gene expression profiles of aged AhR(-/-) and wild-type (wt) mice, using high-throughput RNA sequencing, revealed differential modulation of genes belonging to several AMD-related pathogenic pathways, including inflammation, angiogenesis and extracellular matrix regulation. To investigate AhR regulation of these pathways in wet AMD, we experimentally induced choroidal neovascular lesions in AhR(-/-) mice and found that they measured significantly larger in area and volume compared to age-matched wt mice. Furthermore, these lesions displayed a higher number of ionized calcium-binding adaptor molecule 1-positive (Iba1(+) ) microglial cells and a greater amount of collagen type IV deposition, events also seen in human wet AMD pathology specimens. Consistent with our in vivo observations, AhR knock-down was sufficient to increase choroidal endothelial cell migration and tube formation in vitro. Moreover, AhR knock-down caused an increase in collagen type IV production and secretion in both retinal pigment epithelial (RPE) and choroidal endothelial cell cultures, increased expression of angiogenic and inflammatory molecules, including vascular endothelial growth factor A (VEGFA) and chemokine (C-C motif) ligand 2 (CCL2) in RPE cells, and increased expression of secreted phosphoprotein 1 (SPP1) and transforming growth factor-?1 (TGF?1) in choroidal endothelial cells. Collectively, our findings identify AhR as a regulator of multiple pathogenic pathways in experimentally induced choroidal neovascularization, findings that are consistent with a possible role of AhR in wet AMD. The data discussed in this paper have been deposited in NCBI's Gene Expression Omnibus; GEO Submission No. GSE56983, NCBI Tracking System No. 17021116. © 2014 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland. PMID:25186463

Choudhary, Mayur; Kazmin, Dmitri; Hu, Peng; Thomas, Russell S; McDonnell, Donald P; Malek, Goldis

2015-01-01

121

Authorisation using Attributes from Multiple Authorities A Study of Requirements  

E-print Network

these requirements against 4 generic models for attribute aggregation and makes some recommendations for future and easily managed authorisation infrastructures is increasingly important. Many grid and campus based are granted access to network resources based on their various attributes e.g. their university affiliation

Kent, University of

122

Aspergillus sporulation and mycotoxin production both require inactivation of the FadA G? protein-dependent signaling pathway  

Microsoft Academic Search

The filamentous fungus Aspergillus nidulans contains a cluster of 25 genes that encode enzymes required to synthesize a toxic and carcinogenic secondary metabolite called sterigmatocystin (ST), a precursor of the better known fungal toxin aflatoxin (AF). One ST Cluster (stc) gene, aflR, functions as a pathway-specific transcriptional regulator for activation of other genes in the ST pathway. However, the mechanisms

Julie K. Hicks; Jae-Hyuk Yu; Nancy P. Keller; Thomas H. Adams

1997-01-01

123

Molecular Cell, Vol. 19, 3951, July 1, 2005, Copyright 2005 by Elsevier Inc. DOI 10.1016/j.molcel.2005.05.021 Multiple RNA Surveillance Pathways Limit  

E-print Network

of the expression of mRNAs encod- the siderophore transporters Arn1p­Arn4p are also in- ing iron uptake proteins). These structures provide Rnt1p with the specificity required toThe control of intracellular iron concentration.molcel.2005.05.021 Multiple RNA Surveillance Pathways Limit Aberrant Expression of Iron Uptake m

Chanfreau, Guillaume

124

Ethylene signaling pathway and MAPK cascades are required for AAL toxin-induced programmed cell death.  

PubMed

Programmed cell death (PCD), known as hypersensitive response cell death, has an important role in plant defense response. The signaling pathway of PCD remains unknown. We employed AAL toxin and Nicotiana umbratica to analysis plant PCD. AAL toxin is a pathogenicity factor of the necrotrophic pathogen Alternaria alternata f. sp. lycopersici. N. umbratica is sensitive to AAL toxin, susceptible to pathogens, and effective in Tobacco rattle virus-based virus-induced gene silencing (VIGS). VIGS analyses indicated that AAL toxin-triggered cell death (ACD) is dependent upon the mitogen-activated protein (MAP) kinase kinase MEK2, which is upstream of both salicylic acid-induced protein kinase (SIPK) and wound-induced protein kinase (WIPK) responsible for ethylene (ET) synthesis. ET treatment of MEK2-silenced N. umbratica re-established ACD. In SIPK- and WIPK-silenced N. umbratica, ACD was compromised and ET accumulation was not observed. However, in contrast to the case of MEK2-silenced plants, ET treatment did not induce cell death in SIPK- and WIPK-silenced plants. This work showed that ET-dependent pathway and MAP kinase cascades are required in ACD. Our results suggested that MEK2-SIPK/WIPK cascades have roles in ET biosynthesis; however, SIPK and WIPK have other roles in ET signaling or another pathway leading to cell death by AAL toxin. PMID:22512379

Mase, Keisuke; Mizuno, Takahito; Ishihama, Nobuaki; Fujii, Takayuki; Mori, Hitoshi; Kodama, Motoichiro; Yoshioka, Hirofumi

2012-08-01

125

Genome Regions Involved in Multiple Regulatory Pathways Identified Using GSEL, a Genome-Wide Database of Regulatory Sequence Elements of  

E-print Network

Genome Regions Involved in Multiple Regulatory Pathways Identified Using GSEL, a Genome://www.geobacter.org/research/gsel/). It compiles information on predicted transcription regulatory elements in the genome of G. sulfurreducens. These elements were derived from analyses that employed genome-wide transcription profiling, comparative genomics

Lovley, Derek

126

Multiple Pathways Involved in Porcine Parvovirus Cellular Entry and Trafficking toward the Nucleus?  

PubMed Central

Porcine parvovirus (PPV) is a major cause of reproductive failure in swine. The mechanisms implicated in the first steps of infection that lead to the delivery of the PPV genome to the nucleus are poorly understood. In the present work, a panel of chemical inhibitors was used to dissect the cellular mechanisms involved in establishing a PPV infection. The results demonstrated that following binding to sialic acids on cell surface glycoproteins, the virus used both clathrin-mediated endocytosis and macropinocytosis pathways to gain access into cells. Virus obtained from infected cells was present either as isolated particles or as aggregates, and these two forms could be separated by low-speed centrifugation. Isolated and purified particles strongly preferred entry by clathrin-mediated endocytosis, whereas aggregates clearly favored macropinocytosis. Subsequent endosomal acidification and traffic to the late endosomes were also shown to be essential for infection. The microtubule network was found to be important during the first 10 h of infection, whereas an intact actin network was required for almost the whole viral cycle. Proteasome processing was found to be essential, and capsid proteins were ubiquitinated relatively early during infection. Taken together, these results provided new insights into the first steps of PPV infection, including the use of alternative entry pathways, unique among members of this viral family. PMID:20484503

Boisvert, Maude; Fernandes, Sandra; Tijssen, Peter

2010-01-01

127

Potential role of multiple carbon fixation pathways during lipid accumulation in Phaeodactylum tricornutum  

PubMed Central

Background Phaeodactylum tricornutum is a unicellular diatom in the class Bacillariophyceae. The full genome has been sequenced (<30?Mb), and approximately 20 to 30% triacylglyceride (TAG) accumulation on a dry cell basis has been reported under different growth conditions. To elucidate P. tricornutum gene expression profiles during nutrient-deprivation and lipid-accumulation, cell cultures were grown with a nitrate to phosphate ratio of 20:1 (N:P) and whole-genome transcripts were monitored over time via RNA-sequence determination. Results The specific Nile Red (NR) fluorescence (NR fluorescence per cell) increased over time; however, the increase in NR fluorescence was initiated before external nitrate was completely exhausted. Exogenous phosphate was depleted before nitrate, and these results indicated that the depletion of exogenous phosphate might be an early trigger for lipid accumulation that is magnified upon nitrate depletion. As expected, many of the genes associated with nitrate and phosphate utilization were up-expressed. The diatom-specific cyclins cyc7 and cyc10 were down-expressed during the nutrient-deplete state, and cyclin B1 was up-expressed during lipid-accumulation after growth cessation. While many of the genes associated with the C3 pathway for photosynthetic carbon reduction were not significantly altered, genes involved in a putative C4 pathway for photosynthetic carbon assimilation were up-expressed as the cells depleted nitrate, phosphate, and exogenous dissolved inorganic carbon (DIC) levels. P. tricornutum has multiple, putative carbonic anhydrases, but only two were significantly up-expressed (2-fold and 4-fold) at the last time point when exogenous DIC levels had increased after the cessation of growth. Alternative pathways that could utilize HCO3- were also suggested by the gene expression profiles (e.g., putative propionyl-CoA and methylmalonyl-CoA decarboxylases). Conclusions The results indicate that P. tricornutum continued carbon dioxide reduction when population growth was arrested and different carbon-concentrating mechanisms were used dependent upon exogenous DIC levels. Based upon overall low gene expression levels for fatty acid synthesis, the results also suggest that the build-up of precursors to the acetyl-CoA carboxylases may play a more significant role in TAG synthesis rather than the actual enzyme levels of acetyl-CoA carboxylases per se. The presented insights into the types and timing of cellular responses to inorganic carbon will help maximize photoautotrophic carbon flow to lipid accumulation. PMID:22672912

2012-01-01

128

Genetic Variation in the IL7RA/IL7 Pathway Increases Multiple Sclerosis Susceptibility  

PubMed Central

Multiple sclerosis (MS) is characterized as an autoimmune demyelinating disease. Numerous family studies have confirmed a strong genetic component underlying its etiology. After several decades of frustrating research, the advent and application of affordable genotyping of dense SNP maps in large datasets has ushered in a new era in which rapid progress is being made in our understanding of the genetics underlying many complex traits. For MS, one of the first discoveries to emerge in this new era was the association with rs6897932[T244I] in the interleukin-7 receptor alpha chain (IL7RA) gene (Gregory et al. 2007; International Multiple Sclerosis Genetics Consortium 2007; Lundmark 2007), a discovery that was accompanied by functional data that suggest this variant is likely to be causative rather than a surrogate proxy (Gregory et al. 2007). We hypothesized that variations in other genes functionally related to IL7RA might also influence MS. We investigated this hypothesis by examining genes in the extended biological pathway related to IL7RA to identify novel associations. We identified 73 genes with putative functional relationships to IL7RA and subsequently genotyped 7,865 SNPs in and around these genes using an Illumina Infinium BeadChip assay. Using 2,961 case-control dataset, two of the gene regions examined, IL7 and SOCS1, had significantly associated single-nucleotide polymorphisms (SNPs) that further replicated in an independent case-control dataset (4,831 samples) with joint p-values as high as 8.29×10-6 and 3.48×10-7, respectively, exceeding the threshold for experiment-wise significance. Our results also implicate two additional novel gene regions that are likely to be associated with MS: PRKCE with p-values reaching 3.47×10-4 and BCL2 with p-values reaching 4.32×10-4. The TYK2 gene, which also emerged in our analysis, has recently been associated with MS (Ban et al. 2009). These results help to further delineate the genetic architecture of MS and validate our pathway approach as an effective method to identify novel associations in a complex disease. PMID:20112030

Zuvich, Rebecca L.; McCauley, Jacob L.; Oksenberg, Jorge R.; Sawcer, Stephen J.; De Jager, Philip L.; Aubin, Cristin; Cross, Anne H.; Piccio, Laura; Aggarwal, Neelum T.; Evans, Denis; Hafler, David A.; Compston, Alastair; Hauser, Stephen L.; Pericak-Vance, Margaret A.; Haines, Jonathan L.

2010-01-01

129

Negative Energy: Why Interdisciplinary Physics Requires Multiple Ontologies  

NSDL National Science Digital Library

Much recent work in physics education research has focused on ontological metaphors for energy, particularly the substance ontology and its pedagogical affordances. The concept of negative energy problematizes the substance ontology for energy, but in many instructional settings, the specific difficulties around negative energy are outweighed by the general advantages of the substance ontology. However, we claim that our interdisciplinary setting (a physics class that builds deep connections to biology and chemistry) leads to a different set of considerations and conclusions. In a course designed to draw interdisciplinary connections, the centrality of chemical bond energy in biology necessitates foregrounding negative energy from the beginning. We argue that the emphasis on negative energy requires a combination of substance and location ontologies. The location ontology enables energies both "above" and "below" zero. We present preliminary student data that illustrate difficulties in reasoning about negative energy, and the affordances of the location metaphor.

Dreyfus, Benjamin W.; Geller, Benjamin D.; Gouvea, Julia; Sawtelle, Vashti; Turpen, Chandra; Redish, Edward F.

2014-01-31

130

40 CFR 63.1356 - Sources with multiple emissions limit or monitoring requirements.  

...AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing Industry Other § 63.1356 Sources with multiple emissions limit or monitoring requirements....

2014-07-01

131

40 CFR 63.1356 - Sources with multiple emission limits or monitoring requirements.  

Code of Federal Regulations, 2012 CFR

...FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing Industry Other § 63.1356 Sources with multiple emission limits or monitoring requirements....

2012-07-01

132

40 CFR 63.1356 - Sources with multiple emissions limit or monitoring requirements.  

Code of Federal Regulations, 2013 CFR

...AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing Industry Other § 63.1356 Sources with multiple emissions limit or monitoring requirements....

2013-07-01

133

40 CFR 63.1356 - Sources with multiple emission limits or monitoring requirements.  

Code of Federal Regulations, 2011 CFR

...FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing Industry Other § 63.1356 Sources with multiple emission limits or monitoring requirements....

2011-07-01

134

Theoretical Tracking of Resonance-Enhanced Multiple Ionization Pathways in X-ray Free-Electron Laser Pulses  

NASA Astrophysics Data System (ADS)

We present an extended Monte Carlo rate equation approach to examine the inner-shell ionization dynamics of atoms in an intense x-ray free-electron laser (XFEL) pulse. In addition to photoionization, Auger decay, and fluorescence processes, we include bound-to-bound transitions in the rate equation calculations. Using an efficient computational scheme, we account for "hidden resonances" unveiled during the course of an XFEL pulse. For Ar, the number of possible electron configurations is increased ten-billion-fold over that required under nonresonant conditions. We investigated the complex ionization dynamics of Ar atoms exposed to an 480-eV XFEL pulse, where production of ions above charge state 10 + is not allowed via direct one-photon ionization. We found that resonance-enhanced x-ray multiple ionization pathways play a dominant role in producing these nominally inaccessible charge states. Our calculated results agree with the measured Ar ion yield and pulse-duration dependence. We also predict the surprising ion yields reported earlier for Kr and Xe. The Monte Carlo rate equation method enables theoretical exploration of the complex dynamics of resonant high-intensity x-ray processes.

Ho, Phay J.; Bostedt, Christoph; Schorb, Sebastian; Young, Linda

2014-12-01

135

Theoretical Tracking of Resonance-Enhanced Multiple Ionization Pathways in X-ray Free-Electron Laser Pulses.  

PubMed

We present an extended Monte Carlo rate equation approach to examine the inner-shell ionization dynamics of atoms in an intense x-ray free-electron laser (XFEL) pulse. In addition to photoionization, Auger decay, and fluorescence processes, we include bound-to-bound transitions in the rate equation calculations. Using an efficient computational scheme, we account for "hidden resonances" unveiled during the course of an XFEL pulse. For Ar, the number of possible electron configurations is increased ten-billion-fold over that required under nonresonant conditions. We investigated the complex ionization dynamics of Ar atoms exposed to an 480-eV XFEL pulse, where production of ions above charge state 10+ is not allowed via direct one-photon ionization. We found that resonance-enhanced x-ray multiple ionization pathways play a dominant role in producing these nominally inaccessible charge states. Our calculated results agree with the measured Ar ion yield and pulse-duration dependence. We also predict the surprising ion yields reported earlier for Kr and Xe. The Monte Carlo rate equation method enables theoretical exploration of the complex dynamics of resonant high-intensity x-ray processes. PMID:25554879

Ho, Phay J; Bostedt, Christoph; Schorb, Sebastian; Young, Linda

2014-12-19

136

Resequencing Analysis of the Candidate Tyrosine Kinase and RAS Pathway Gene Families in Multiple Myeloma  

PubMed Central

Multiple myeloma (MM) is an incurable, B-cell malignancy, characterized by the clonal proliferation and accumulation of malignant plasma cells in bone marrow. Despite recent advances in understanding of genomic aberrations, a comprehensive catalogue of clinically actionable mutations in MM is just beginning to emerge. The tyrosine kinase (TK) and RAS oncogenes, which encode important regulators of various signaling pathways, are among the most frequently altered gene families in cancer. To clarify the role of TK and RAS genes in pathogenesis of MM, we performed a systematic, targeted screening of mutations on prioritized RAS and TK genes, in CD138 sorted bone marrow specimens from 42 untreated patients. We identified a total of 24 mutations in KRAS, PIK3CA, INSR, LTK and MERTK genes. In particular, seven novel mutations in addition to known KRAS mutations were observed. Prediction analysis tools, PolyPhen and SIFT were used to assess the functional significance of these novel mutations. Our analysis predicted that these mutations may have a deleterious effect, resulting in functional alteration of proteins involved in the pathogenesis of myeloma. While further investigation is needed to determine the functional consequences of these proteins, mutational testing of the RAS and TK genes in larger myeloma cohorts might be also useful to establish the recurrent nature of these mutations. PMID:22939401

Hucthagowder, Vishwanathan; Meyer, Rekha; Mullins, Chelsea; Nagarajan, Rakesh; DiPersio, John F.; Vij, Ravi; Tomasson, Michael H.; Kulkarni, Shashikant

2012-01-01

137

DEPTOR is linked to a TORC1-p21 survival proliferation pathway in multiple myeloma cells  

PubMed Central

We investigated the mechanism by which gene silencing of the mTOR inhibitor, DEPTOR, induces cytoreductive effects on multiple myeloma (MM) cells. DEPTOR knockdown resulted in anti-MM effects in several MM cell lines. Using an inducible shRNA to silence DEPTOR, 8226 MM cells underwent TORC1 activation, downregulation of AKT/SGK activity, apoptosis, cell cycle arrest and senescence. These latter cytotoxic effects were prevented by TORC1 paralysis (Raptor knockdown) but not by over-expression of AKT activity. In addition, DEPTOR knockdown-induced MM death was not associated with activation of the unfolded protein response, suggesting that enhanced ER stress did not play a role. In contrast, DEPTOR knockdown in 8226 cells induced p21 expression, independent of p53, and p21 knockdown prevented all of the cytotoxic effects following DEPTOR silencing. DEPTOR silencing resulted in p21 upregulation in additional MM cell lines. Furthermore, DEPTOR silencing in a murine xenograft model resulted in anti-MM effects associated with p21 upregulation. DEPTOR knockdown also resulted in a decreased expression of p21-targeting miRNAs and transfection of miRNA mimics prevented p21 upregulation and apoptosis following DEPTOR silencing. Use of a shRNA-resistant DEPTOR construct ruled out off-target effects of the shRNA. These results indicate that DEPTOR regulates growth and survival of MM cells via a TORC1/p21 pathway and suggest an involvement of p21-targeted miRNAs. PMID:25568666

Yang, Yonghui; Bardeleben, Carolyne; Frost, Patrick; Hoang, Bao; Shi, Yijiang; Finn, Richard; Gera, Joseph; Lichtenstein, Alan

2014-01-01

138

Adenovirus Core Protein pVII Is Translocated into the Nucleus by Multiple Import Receptor Pathways  

PubMed Central

Adenoviruses are nonenveloped viruses with an ?36-kb double-stranded DNA genome that replicate in the nucleus. Protein VII, an abundant structural component of the adenovirus core that is strongly associated with adenovirus DNA, is imported into the nucleus contemporaneously with the adenovirus genome shortly after virus infection and may promote DNA import. In this study, we evaluated whether protein VII uses specific receptor-mediated mechanisms for import into the nucleus. We found that it contains potent nuclear localization signal (NLS) activity by transfection of cultured cells with protein VII fusion constructs and by microinjection of cells with recombinant protein VII fusions. We identified three NLS-containing regions in protein VII by deletion mapping and determined important NLS residues by site-specific mutagenesis. We found that recombinant protein VII and its NLS-containing domains strongly and specifically bind to importin ?, importin ?, importin 7, and transportin, which are among the most abundant cellular nuclear import receptors. Moreover, these receptors can mediate the nuclear import of protein VII fusions in vitro in permeabilized cells. Considered together, these data support the hypothesis that protein VII is a major NLS-containing adaptor for receptor-mediated import of adenovirus DNA and that multiple import pathways are utilized to promote efficient nuclear entry of the viral genome. PMID:16973564

Wodrich, Harald; Cassany, Aurelia; D'Angelo, Maximiliano A.; Guan, Tinglu; Nemerow, Glen; Gerace, Larry

2006-01-01

139

Multiple signaling pathways regulate the transcriptional activity of the orphan nuclear receptor NURR1  

PubMed Central

The orphan nuclear receptor nurr1 (NR4A2) is an essential transcription factor for the acquisition and maintenance of the phenotype of dopamine (DA)-synthesizing neurons in the mesencephalon. Although structurally related to ligand-regulated nuclear receptors, nurr1 is functionally atypical due to its inability to bind a cognate ligand and to activate transcription following canonical nuclear receptor (NR) rules. Importantly, the physiological stimuli that activate this NR and the signaling proteins that regulate its transcriptional activity in mesencephalic neurons are unknown. We used an affinity chromatography approach and CSM14.1 cells of mesencephalic origin to isolate and identify several proteins that interact directly with nurr1 and regulate its transcriptional activity. Notably, we demonstrate that the mitogen-activated protein kinases, ERK2 and ERK5, elevate, whereas LIM Kinase 1 inhibits nurr1 transcriptional activity. Furthermore, nurr1 recruits ERK5 to a NBRE-containing promoter and is a potential substrate for this kinase. We have identified amino acids in the A/B domain of nurr1 important for mediating the ERK5 activating effects on nurr1 transcriptional activity. Our results suggest that nurr1 acts as a point of convergence for multiple signaling pathways that likely play a critical role in differentiation and phenotypic expression of dopaminergic (DAergic) neurons. PMID:17020917

Sacchetti, Paola; Carpentier, Rodolphe; Ségard, Pascaline; Olivé-Cren, Cécile; Lefebvre, Philippe

2006-01-01

140

Frequent engagement of the classical and alternative NF-?B pathways by diverse genetic abnormalities in multiple myeloma  

PubMed Central

Summary Mechanisms of constitutive NF-?B signaling in multiple myeloma are unknown. An inhibitor of I?B kinase beta (IKK?), targeting the classical NF-?B pathway, was lethal to many myeloma cell lines. Several cell lines had elevated expression of NIK due to genomic alterations or protein stabilization while others had inactivating mutations of TRAF3; both kinds of abnormality triggered the classical and alternative NF-?B pathways. A majority of primary myeloma patient samples and cell lines had elevated NF-?B target gene expression, often associated with genetic or epigenetic alteration of NIK, TRAF3, CYLD, BIRC2/BIRC3, CD40, NFKB1, or NFKB2. These data demonstrate that addiction to the NF-?B pathway is frequent in myeloma and suggest that IKK? inhibitors hold promise for the treatment of this disease. Significance Here we show the importance of classical NF-?B signaling in multiple myeloma. We discovered diverse genetic and epigenetic mechanisms leading to NF-?B activity in myeloma cell lines and patient samples. Targeted disruption of classical NF-?B signaling with a small molecule inhibitor of IKK? blocked myeloma cell proliferation and induced cell death. Most primary MM patient samples had evidence of NF-?B pathway activation, suggesting that therapeutic strategies targeting the classical NF-?B pathway should be pursued. PMID:17692804

Annunziata, Christina M.; Davis, R. Eric; Demchenko, Yulia; Bellamy, William; Gabrea, Ana; Zhan, Fenghuang; Lenz, Georg; Hanamura, Ichiro; Wright, George; Xiao, Wenming; Dave, Sandeep; Hurt, Elaine M.; Tan, Bruce; Zhao, Hong; Stephens, Owen; Santra, Madhumita; Williams, David R.; Dang, Lenny; Barlogie, Bart; Shaughnessy, John D.; Kuehl, W. Michael; Staudt, Louis M.

2009-01-01

141

Kinetic modelling of phospholipid synthesis in Plasmodium knowlesi unravels crucial steps and relative importance of multiple pathways  

PubMed Central

Background Plasmodium is the causal parasite of malaria, infectious disease responsible for the death of up to one million people each year. Glycerophospholipid and consequently membrane biosynthesis are essential for the survival of the parasite and are targeted by a new class of antimalarial drugs developed in our lab. In order to understand the highly redundant phospholipid synthethic pathways and eventual mechanism of resistance to various drugs, an organism specific kinetic model of these metabolic pathways need to be developed in Plasmodium species. Results Fluxomic data were used to build a quantitative kinetic model of glycerophospholipid pathways in Plasmodium knowlesi. In vitro incorporation dynamics of phospholipids unravels multiple synthetic pathways. A detailed metabolic network with values of the kinetic parameters (maximum rates and Michaelis constants) has been built. In order to obtain a global search in the parameter space, we have designed a hybrid, discrete and continuous, optimization method. Discrete parameters were used to sample the cone of admissible fluxes, whereas the continuous Michaelis and maximum rates constants were obtained by local minimization of an objective function.The model was used to predict the distribution of fluxes within the network of various metabolic precursors. The quantitative analysis was used to understand eventual links between different pathways. The major source of phosphatidylcholine (PC) is the CDP-choline Kennedy pathway. In silico knock-out experiments showed comparable importance of phosphoethanolamine-N-methyltransferase (PMT) and phosphatidylethanolamine-N-methyltransferase (PEMT) for PC synthesis. The flux values indicate that, major part of serine derived phosphatidylethanolamine (PE) is formed via serine decarboxylation, whereas major part of phosphatidylserine (PS) is formed by base-exchange reactions. Sensitivity analysis of CDP-choline pathway shows that the carrier-mediated choline entry into the parasite and the phosphocholine cytidylyltransferase reaction have the largest sensitivity coefficients in this pathway, but does not distinguish a reaction as an unique rate-limiting step. Conclusion We provide a fully parametrized kinetic model for the multiple phospholipid synthetic pathways in P. knowlesi. This model has been used to clarify the relative importance of the various reactions in these metabolic pathways. Future work extensions of this modelling strategy will serve to elucidate the regulatory mechanisms governing the development of Plasmodium during its blood stages, as well as the mechanisms of action of drugs on membrane biosynthetic pathways and eventual mechanisms of resistance. PMID:24209716

2013-01-01

142

Identification of Common Biological Pathways and Drug Targets Across Multiple Respiratory Viruses Based on Human Host Gene Expression Analysis  

PubMed Central

Background Pandemic and seasonal respiratory viruses are a major global health concern. Given the genetic diversity of respiratory viruses and the emergence of drug resistant strains, the targeted disruption of human host-virus interactions is a potential therapeutic strategy for treating multi-viral infections. The availability of large-scale genomic datasets focused on host-pathogen interactions can be used to discover novel drug targets as well as potential opportunities for drug repositioning. Methods/Results In this study, we performed a large-scale analysis of microarray datasets involving host response to infections by influenza A virus, respiratory syncytial virus, rhinovirus, SARS-coronavirus, metapneumonia virus, coxsackievirus and cytomegalovirus. Common genes and pathways were found through a rigorous, iterative analysis pipeline where relevant host mRNA expression datasets were identified, analyzed for quality and gene differential expression, then mapped to pathways for enrichment analysis. Possible repurposed drugs targets were found through database and literature searches. A total of 67 common biological pathways were identified among the seven different respiratory viruses analyzed, representing fifteen laboratories, nine different cell types, and seven different array platforms. A large overlap in the general immune response was observed among the top twenty of these 67 pathways, adding validation to our analysis strategy. Of the top five pathways, we found 53 differentially expressed genes affected by at least five of the seven viruses. We suggest five new therapeutic indications for existing small molecules or biological agents targeting proteins encoded by the genes F3, IL1B, TNF, CASP1 and MMP9. Pathway enrichment analysis also identified a potential novel host response, the Parkin-Ubiquitin Proteasomal System (Parkin-UPS) pathway, which is known to be involved in the progression of neurodegenerative Parkinson's disease. Conclusions Our study suggests that multiple and diverse respiratory viruses invoke several common host response pathways. Further analysis of these pathways suggests potential opportunities for therapeutic intervention. PMID:22432004

Smith, Steven B.; Dampier, William; Tozeren, Aydin; Brown, James R.; Magid-Slav, Michal

2012-01-01

143

The role of the PI3K-Akt signal transduction pathway in Autographa californica multiple nucleopolyhedrovirus infection of Spodoptera frugiperda cells  

SciTech Connect

Many viruses activate the phosphatidylinositol 3-kinase (PI3K)-Akt signaling pathway, thereby modulating diverse downstream signaling pathways associated with antiapoptosis, proliferation, cell cycling, protein synthesis and glucose metabolism, in order to augment their replication. To date, the role of the PI3K-Akt pathway in Baculovirus replication has not been defined. In the present study, we demonstrate that infection of Sf9 cells with Autographa californica multiple nucleopolyhedrovirus (AcMNPV) elevated cellular Akt phosphorylation at 1 h post-infection. The maximum Akt phosphorylation occurred at 6 h post-infection and remained unchanged until 18 h post-infection. The PI3K-specific inhibitor, LY294002, suppressed Akt phosphorylation in a dose-dependent manner, suggesting that AcMNPV-induced Akt phosphorylation is PI3K-dependent. The inhibition of PI3K-Akt activation by LY294002 significantly reduced the viral yield, including a reduction in budded viruses and occlusion bodies. The virus production was reduced only when the inhibitor was added within 24 h of infection, implying that activation of PI3K occurred early in infection. Correspondingly, both viral DNA replication and late (VP39) and very late (POLH) viral protein expression were impaired by LY294002 treatment; LY294002 had no effect on immediate-early (IE1) and early-late (GP64) protein expression. These results demonstrate that the PI3K-Akt pathway is required for efficient Baculovirus replication.

Xiao Wei; Yang Yi; Weng Qingbei; Lin Tiehao; Yuan Meijin [State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou 510275 (China); Yang Kai, E-mail: yangkai@mail.sysu.edu.c [State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou 510275 (China); Pang Yi [State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou 510275 (China)

2009-08-15

144

TGF-? induction of FGF-2 expression in stromal cells requires integrated smad3 and MAPK pathways  

PubMed Central

Transforming Growth Factor-? (TGF-?) regulates the reactive stroma microenvironment associated with most carcinomas and mediates expression of many stromal derived factors important for tumor progression, including FGF-2 and CTGF. TGF-? is over-expressed in most carcinomas, and FGF-2 action is important in tumor-induced angiogenesis. The signaling mechanisms of how TGF-? regulates FGF-2 expression in the reactive stroma microenvironment are not understood. Accordingly, we have assessed key signaling pathways that mediate TGF-?1-induced FGF-2 expression in prostate stromal fibroblasts and mouse embryo fibroblasts (MEFs) null for Smad2 and Smad3. TGF-?1 induced phosphorylation of Smad2, Smad3, p38 and ERK1/2 proteins in both control MEFs and prostate fibroblasts. Of these, Smad3, but not Smad2 was found to be required for TGF-?1 induction of FGF-2 expression in stromal cells. ChIP analysis revealed a Smad3/Smad4 complex was associated with the -1.9 to -2.3 kb upstream proximal promoter of the FGF-2 gene, further suggesting a Smad3-specific regulation. In addition, chemical inhibition of p38 or ERK1/2 MAPK activity also blocked TGF-?1-induced FGF-2 expression in a Smad3-independent manner. Conversely, inhibition of JNK signaling enhanced FGF-2 expression. Together, these data indicate that expression of FGF-2 in fibroblasts in the tumor stromal cell microenvironment is coordinately dependent on both intact Smad3 and MAP kinase signaling pathways. These pathways and key downstream mediators of TGF-? action in the tumor reactive stroma microenvironment, may evolve as putative targets for therapeutic intervention. PMID:25374926

Strand, Douglas W; Liang, Yao-Yun; Yang, Feng; Barron, David A; Ressler, Steven J; Schauer, Isaiah G; Feng, Xin-Hua; Rowley, David R

2014-01-01

145

Integrated QSAR study for inhibitors of hedgehog signal pathway against multiple cell lines:a collaborative filtering method  

PubMed Central

Background The Hedgehog Signaling Pathway is one of signaling pathways that are very important to embryonic development. The participation of inhibitors in the Hedgehog Signal Pathway can control cell growth and death, and searching novel inhibitors to the functioning of the pathway are in a great demand. As the matter of fact, effective inhibitors could provide efficient therapies for a wide range of malignancies, and targeting such pathway in cells represents a promising new paradigm for cell growth and death control. Current research mainly focuses on the syntheses of the inhibitors of cyclopamine derivatives, which bind specifically to the Smo protein, and can be used for cancer therapy. While quantitatively structure-activity relationship (QSAR) studies have been performed for these compounds among different cell lines, none of them have achieved acceptable results in the prediction of activity values of new compounds. In this study, we proposed a novel collaborative QSAR model for inhibitors of the Hedgehog Signaling Pathway by integration the information from multiple cell lines. Such a model is expected to substantially improve the QSAR ability from single cell lines, and provide useful clues in developing clinically effective inhibitors and modifications of parent lead compounds for target on the Hedgehog Signaling Pathway. Results In this study, we have presented: (1) a collaborative QSAR model, which is used to integrate information among multiple cell lines to boost the QSAR results, rather than only a single cell line QSAR modeling. Our experiments have shown that the performance of our model is significantly better than single cell line QSAR methods; and (2) an efficient feature selection strategy under such collaborative environment, which can derive the commonly important features related to the entire given cell lines, while simultaneously showing their specific contributions to a specific cell-line. Based on feature selection results, we have proposed several possible chemical modifications to improve the inhibitor affinity towards multiple targets in the Hedgehog Signaling Pathway. Conclusions Our model with the feature selection strategy presented here is efficient, robust, and flexible, and can be easily extended to model large-scale multiple cell line/QSAR data. The data and scripts for collaborative QSAR modeling are available in the Additional file 1. PMID:22849868

2012-01-01

146

EFF-1-mediated regenerative axonal fusion requires components of the apoptotic pathway.  

PubMed

Functional regeneration after nervous system injury requires transected axons to reconnect with their original target tissue. Axonal fusion, a spontaneous regenerative mechanism identified in several species, provides an efficient means of achieving target reconnection as a regrowing axon is able to contact and fuse with its own separated axon fragment, thereby re-establishing the original axonal tract. Here we report a molecular characterization of this process in Caenorhabditis elegans, revealing dynamic changes in the subcellular localization of the EFF-1 fusogen after axotomy, and establishing phosphatidylserine (PS) and the PS receptor (PSR-1) as critical components for axonal fusion. PSR-1 functions cell-autonomously in the regrowing neuron and, instead of acting in its canonical signalling pathway, acts in a parallel phagocytic pathway that includes the transthyretin protein TTR-52, as well as CED-7, NRF-5 and CED-6 (refs 9, 10, 11, 12). We show that TTR-52 binds to PS exposed on the injured axon, and can restore fusion several hours after injury. We propose that PS functions as a 'save-me' signal for the distal fragment, allowing conserved apoptotic cell clearance molecules to function in re-establishing axonal integrity during regeneration of the nervous system. PMID:25567286

Neumann, Brent; Coakley, Sean; Giordano-Santini, Rosina; Linton, Casey; Lee, Eui Seung; Nakagawa, Akihisa; Xue, Ding; Hilliard, Massimo A

2015-01-01

147

Genetic Dissection of Differential Signaling Threshold Requirements for the Wnt/?-Catenin Pathway In Vivo  

PubMed Central

Contributions of null and hypomorphic alleles of Apc in mice produce both developmental and pathophysiological phenotypes. To ascribe the resulting genotype-to-phenotype relationship unambiguously to the Wnt/?-catenin pathway, we challenged the allele combinations by genetically restricting intracellular ?-catenin expression in the corresponding compound mutant mice. Subsequent evaluation of the extent of resulting Tcf4-reporter activity in mouse embryo fibroblasts enabled genetic measurement of Wnt/?-catenin signaling in the form of an allelic series of mouse mutants. Different permissive Wnt signaling thresholds appear to be required for the embryonic development of head structures, adult intestinal polyposis, hepatocellular carcinomas, liver zonation, and the development of natural killer cells. Furthermore, we identify a homozygous Apc allele combination with Wnt/?-catenin signaling capacity similar to that in the germline of the Apcmin mice, where somatic Apc loss-of-heterozygosity triggers intestinal polyposis, to distinguish whether co-morbidities in Apcmin mice arise independently of intestinal tumorigenesis. Together, the present genotype–phenotype analysis suggests tissue-specific response levels for the Wnt/?-catenin pathway that regulate both physiological and pathophysiological conditions. PMID:20084116

Burke, Zoe D.; Faux, Maree C.; Samuel, Michael S.; Jarnicki, Andrew G.; Winbanks, Catherine E.; Newton, Ian P.; Meniel, Valerie S.; Suzuki, Hiromu; Stacker, Steven A.; Näthke, Inke S.; Tosh, David; Huelsken, Joerg; Clarke, Alan R.; Heath, Joan K.; Sansom, Owen J.; Ernst, Matthias

2010-01-01

148

Rhizobium–legume symbiosis shares an exocytotic pathway required for arbuscule formation  

PubMed Central

Endosymbiotic interactions are characterized by the formation of specialized membrane compartments, by the host in which the microbes are hosted, in an intracellular manner. Two well-studied examples, which are of major agricultural and ecological importance, are the widespread arbuscular mycorrhizal symbiosis and the Rhizobium–legume symbiosis. In both symbioses, the specialized host membrane that surrounds the microbes forms a symbiotic interface, which facilitates the exchange of, for example, nutrients in a controlled manner and, therefore, forms the heart of endosymbiosis. Despite their key importance, the molecular and cellular mechanisms underlying the formation of these membrane interfaces are largely unknown. Recent studies strongly suggest that the Rhizobium–legume symbiosis coopted a signaling pathway, including receptor, from the more ancient arbuscular mycorrhizal symbiosis to form a symbiotic interface. Here, we show that two highly homologous exocytotic vesicle-associated membrane proteins (VAMPs) are required for formation of the symbiotic membrane interface in both interactions. Silencing of these Medicago VAMP72 genes has a minor effect on nonsymbiotic plant development and nodule formation. However, it blocks symbiosome as well as arbuscule formation, whereas root colonization by the microbes is not affected. Identification of these VAMP72s as common symbiotic regulators in exocytotic vesicle trafficking suggests that the ancient exocytotic pathway forming the periarbuscular membrane compartment has also been coopted in the Rhizobium–legume symbiosis. PMID:22566631

Ivanov, Sergey; Fedorova, Elena E.; Limpens, Erik; De Mita, Stephane; Genre, Andrea; Bonfante, Paola; Bisseling, Ton

2012-01-01

149

Ancient and Novel Small RNA Pathways Compensate for the Loss of piRNAs in Multiple Independent Nematode Lineages  

PubMed Central

Small RNA pathways act at the front line of defence against transposable elements across the Eukaryota. In animals, Piwi interacting small RNAs (piRNAs) are a crucial arm of this defence. However, the evolutionary relationships among piRNAs and other small RNA pathways targeting transposable elements are poorly resolved. To address this question we sequenced small RNAs from multiple, diverse nematode species, producing the first phylum-wide analysis of how small RNA pathways evolve. Surprisingly, despite their prominence in Caenorhabditis elegans and closely related nematodes, piRNAs are absent in all other nematode lineages. We found that there are at least two evolutionarily distinct mechanisms that compensate for the absence of piRNAs, both involving RNA-dependent RNA polymerases (RdRPs). Whilst one pathway is unique to nematodes, the second involves Dicer-dependent RNA-directed DNA methylation, hitherto unknown in animals, and bears striking similarity to transposon-control mechanisms in fungi and plants. Our results highlight the rapid, context-dependent evolution of small RNA pathways and suggest piRNAs in animals may have replaced an ancient eukaryotic RNA-dependent RNA polymerase pathway to control transposable elements. PMID:25668728

Sarkies, Peter; Selkirk, Murray E.; Jones, John T.; Blok, Vivian; Boothby, Thomas; Goldstein, Bob; Hanelt, Ben; Ardila-Garcia, Alex; Fast, Naomi M.; Schiffer, Phillip M.; Kraus, Christopher; Taylor, Mark J.; Koutsovoulos, Georgios; Blaxter, Mark L.; Miska, Eric A.

2015-01-01

150

Ancient and Novel Small RNA Pathways Compensate for the Loss of piRNAs in Multiple Independent Nematode Lineages.  

PubMed

Small RNA pathways act at the front line of defence against transposable elements across the Eukaryota. In animals, Piwi interacting small RNAs (piRNAs) are a crucial arm of this defence. However, the evolutionary relationships among piRNAs and other small RNA pathways targeting transposable elements are poorly resolved. To address this question we sequenced small RNAs from multiple, diverse nematode species, producing the first phylum-wide analysis of how small RNA pathways evolve. Surprisingly, despite their prominence in Caenorhabditis elegans and closely related nematodes, piRNAs are absent in all other nematode lineages. We found that there are at least two evolutionarily distinct mechanisms that compensate for the absence of piRNAs, both involving RNA-dependent RNA polymerases (RdRPs). Whilst one pathway is unique to nematodes, the second involves Dicer-dependent RNA-directed DNA methylation, hitherto unknown in animals, and bears striking similarity to transposon-control mechanisms in fungi and plants. Our results highlight the rapid, context-dependent evolution of small RNA pathways and suggest piRNAs in animals may have replaced an ancient eukaryotic RNA-dependent RNA polymerase pathway to control transposable elements. PMID:25668728

Sarkies, Peter; Selkirk, Murray E; Jones, John T; Blok, Vivian; Boothby, Thomas; Goldstein, Bob; Hanelt, Ben; Ardila-Garcia, Alex; Fast, Naomi M; Schiffer, Phillip M; Kraus, Christopher; Taylor, Mark J; Koutsovoulos, Georgios; Blaxter, Mark L; Miska, Eric A

2015-02-01

151

Pseudomonas aeruginosa Uses Multiple Pathways To Acquire Iron during Chronic Infection in Cystic Fibrosis Lungs  

PubMed Central

Pseudomonas aeruginosa chronically infects the lungs of more than 80% of adult patients with cystic fibrosis (CF) and is a major contributor to the progression of disease pathology. P. aeruginosa requires iron for growth and has multiple iron uptake systems that have been studied in bacteria grown in laboratory culture. The purpose of this research was to determine which of these are active during infection in CF. RNA was extracted from 149 sputum samples obtained from 23 CF patients. Reverse transcription–quantitative real-time PCR (RT-qPCR) was used to measure the expression of P. aeruginosa genes encoding transport systems for the siderophores pyoverdine and pyochelin, for heme, and for ferrous ions. Expression of P. aeruginosa genes could be quantified in 89% of the sputum samples. Expression of genes associated with siderophore-mediated iron uptake was detected in most samples but was at low levels in some samples, indicating that other iron uptake mechanisms are active. Expression of genes encoding heme transport systems was also detected in most samples, indicating that heme uptake occurs during infection in CF. feoB expression was detected in all sputum samples, implying an important role for ferrous ion uptake by P. aeruginosa in CF. Our data show that multiple P. aeruginosa iron uptake mechanisms are active in chronic CF infection and that RT-qPCR of RNA extracted from sputum provides a powerful tool for investigating bacterial physiology during infection in CF. PMID:23690396

Konings, Anna F.; Martin, Lois W.; Sharples, Katrina J.; Roddam, Louise F.; Latham, Roger; Reid, David W.

2013-01-01

152

Precise lamination of retinal axons generates multiple parallel input pathways in the tectum  

PubMed Central

The axons of retinal ganglion cells (RGCs) form topographic connections in the optic tectum, recreating a two-dimensional map of the visual field in the midbrain. RGC axons are also targeted to specific positions along the laminar axis of the tectum. Understanding the sensory transformations performed by the tectum requires identification of the rules that control the formation of synaptic laminae by RGC axons. However, there is little information regarding the spatial relationships between multiple axons as they establish laminar and retinotopic arborization fields within the same region of neuropil. Moreover, the contribution of RGC axon lamination to the processing of visual information is unknown. We have utilized Brainbow genetic labeling to visualize groups of individually identifiable axons during the assembly of a precise laminar map in the tectum. Live imaging of multiple RGCs revealed that axons target specific sublaminar positions during initial innervation and maintain their relative laminar positions throughout early larval development, ruling out a model for lamina selection based on iterative refinements. During this period of laminar stability, RGC arbors undergo structural rearrangements that shift their relative retinotopic positions. Analysis of cell type-specific lamination patterns revealed that distinct combinations of RGCs converge to form each sublamina, and this input heterogeneity correlates with different functional responses to visual stimuli. These findings suggest that lamina-specific sorting of retinal inputs provides an anatomical blueprint for the integration of visual features in the tectum. PMID:23486973

Robles, Estuardo; Filosa, Alessandro; Baier, Herwig

2013-01-01

153

Reactions of diborane with ammonia and ammonia borane: catalytic effects for multiple pathways for hydrogen release.  

PubMed

High-level electronic structure calculations have been used to construct portions of the potential energy surfaces related to the reaction of diborane with ammonia and ammonia borane (B2H6 + NH3 and B2H6 + BH3NH3)to probe the molecular mechanism of H2 release. Geometries of stationary points were optimized at the MP2/aug-cc-pVTZ level. Total energies were computed at the coupled-cluster CCSD(T) theory level with the correlation-consistent basis sets. The results show a wide range of reaction pathways for H2 elimination. The initial interaction of B2H6 + NH3 leads to a weak preassociation complex, from which a B-H-B bridge bond is broken giving rise to a more stable H3BHBH2NH3 adduct. This intermediate, which is also formed from BH3NH3 + BH3, is connected with at least six transition states for H2 release with energies 18-93 kal/mol above the separated reactants. The lowest-lying transition state is a six-member cycle, in which BH3exerts a bifunctional catalytic effect accelerating H2 generation within a B-H-H-N framework. Diborane also induces a catalytic effect for H2 elimination from BH3NH3 via a three-step pathway with cyclic transition states. Following conformational changes, the rate-determining transition state for H2 release is approximately 27 kcal/mol above the B2H6 + BH3NH3 reactants, as compared with an energy barrier of approximately 37 kcal/mol for H2 release from BH3NH3. The behavior of two separated BH3 molecules is more complex and involves multiple reaction pathways. Channels from diborane or borane initially converge to a complex comprising the H3BHBH2NH3adduct plus BH3. The interaction of free BH3 with the BH3 moiety of BH3NH3 via a six-member transition state with diborane type of bonding leads to a lower-energy transition state. The corresponding energy barrier is approximately 8 kcal/mol, relative to the reference point H3BHBH2NH3 adduct + BH3. These transition states are 27-36 kcal/mol above BH3NH3 + B2H6, but 1-9 kcal/mol below the separated reactants BH3NH3 + 2 BH3. Upon chemical activation of B2H6 by forming 2 BH3, there should be sufficient internal energy to undergo spontaneous H2 release. Proceeding in the opposite direction, the H2 regeneration of the products of the B2H6 + BH3NH3reaction should be a feasible process under mild thermal conditions. PMID:18767778

Nguyen, Vinh Son; Matus, Myrna H; Nguyen, Minh Tho; Dixon, David A

2008-10-01

154

Multiple pathways of angiotensin I conversion and their functional role in the canine penile corpus cavernosum.  

PubMed

Multiple pathways of angiotensin (Ang) I conversion and their functional role in the canine penile corpus cavernosum were investigated. Biochemical analysis revealed high activities of angiotensin-converting enzyme (ACE) (6.9 +/- 1.7 mU/mg of protein, mean +/- S.E.M., n = 8) and chymase-like enzyme (4.0 +/- 1.4 mU/mg of protein). Functional recording of isometric tension showed that Ang I (3 x 10(-7) M) induced a tension of 0.17 +/- 0.05 g (n = 5), which was reduced to about 60% by pretreatment with an ACE inhibitor, lisinopril (10(-6) M), and almost completely blocked by lisinopril in combination with a chymase inhibitor, chymostatin (10(-4) M). Binding sites for ACE and Ang II receptors were studied by in vitro autoradiography using 125I-351A and 125I-[Sar1, Ile8]Ang II as ligands, respectively. Dense binding of ACE appeared in the endothelial layer of the corpus cavernosum penis, and Ang II receptors were localized in the trabecular smooth muscle layer. An AT1 receptor antagonist, CV-11974 (10(-6) M), markedly displaced 125I-[Sar1, Ile8]Ang II bindings, indicating that the corpus cavernosum penis contains AT1 receptors exclusively. Immunohistochemical studies demonstrated ACE in the endothelium of the corpus cavernosum penis. Mast cells that produce chymase were present mainly in the cavernosal area. These results demonstrate that chymase, in addition to ACE, is involved in the contraction of canine penile corpus cavernosum through local Ang II formation. PMID:11408523

Iwamoto, Y; Song, K; Takai, S; Yamada, M; Jin, D; Sakaguchi, M; Ueda, H; Katsuoka, Y; Miyazaki, M

2001-07-01

155

Piwi Is Required in Multiple Cell Types to Control Germline Stem Cell Lineage Development in the Drosophila Ovary  

PubMed Central

The piRNA pathway plays an important role in maintaining genome stability in the germ line by silencing transposable elements (TEs) from fly to mammals. As a highly conserved piRNA pathway component, Piwi is widely expressed in both germ cells and somatic cells in the Drosophila ovary and is required for piRNA production in both cell types. In addition to its known role in somatic cap cells to maintain germline stem cells (GSCs), this study has demonstrated that Piwi has novel functions in somatic cells and germ cells of the Drosophila ovary to promote germ cell differentiation. Piwi knockdown in escort cells causes a reduction in escort cell (EC) number and accumulation of undifferentiated germ cells, some of which show active BMP signaling, indicating that Piwi is required to maintain ECs and promote germ cell differentiation. Simultaneous knockdown of dpp, encoding a BMP, in ECs can partially rescue the germ cell differentiation defect, indicating that Piwi is required in ECs to repress dpp. Consistent with its key role in piRNA production, TE transcripts increase significantly and DNA damage is also elevated in the piwi knockdown somatic cells. Germ cell-specific knockdown of piwi surprisingly causes depletion of germ cells before adulthood, suggesting that Piwi might control primordial germ cell maintenance or GSC establishment. Finally, Piwi inactivation in the germ line of the adult ovary leads to gradual GSC loss and germ cell differentiation defects, indicating the intrinsic role of Piwi in adult GSC maintenance and differentiation. This study has revealed new germline requirement of Piwi in controlling GSC maintenance and lineage differentiation as well as its new somatic function in promoting germ cell differentiation. Therefore, Piwi is required in multiple cell types to control GSC lineage development in the Drosophila ovary. PMID:24658126

Ma, Xing; Wang, Su; Do, Trieu; Song, Xiaoqing; Inaba, Mayu; Nishimoto, Yoshiya; Liu, Lu-ping; Gao, Yuan; Mao, Ying; Li, Hui; McDowell, William; Park, Jungeun; Malanowski, Kate; Peak, Allison; Perera, Anoja; Li, Hua; Gaudenz, Karin; Haug, Jeff; Yamashita, Yukiko; Lin, Haifan; Ni, Jian-quan; Xie, Ting

2014-01-01

156

Assessing structure and function of the afferent visual pathway in multiple sclerosis and associated optic neuritis  

Microsoft Academic Search

The afferent visual pathway is commonly affected in MS. Assessment of the afferent visual pathway using clinical, imaging\\u000a and electrophysiological methods not only provides insights into the pathophysiology of MS, but also provides a method of\\u000a investigating potential therapeutic measures in MS. This review summarises the various assessment methods, in particular imaging\\u000a techniques of the visual pathway. Retinal nerve fibre

Madhan Kolappan; Andrew P. D. Henderson; Thomas M. Jenkins; Claudia A. M. Wheeler-Kingshott; Gordon T. Plant; Alan J. Thompson; David H. Miller

2009-01-01

157

Biosynthesis of 2-Hydroxyethylphosphonate, an Unexpected Intermediate Common to Multiple Phosphonate Biosynthetic Pathways*S?  

PubMed Central

Phosphonic acids encompass a common yet chemically diverse class of natural products that often possess potent biological activities. Here we report that, despite the significant structural differences among many of these compounds, their biosynthetic routes contain an unexpected common intermediate, 2-hydroxyethyl-phosphonate, which is synthesized from phosphonoacetaldehyde by a distinct family of metal-dependent alcohol dehydrogenases (ADHs). Although the sequence identity of the ADH family members is relatively low (34–37%), in vitro biochemical characterization of the homologs involved in biosynthesis of the antibiotics fosfomycin, phosphinothricin tripeptide, and dehydrophos (formerly A53868) unequivocally confirms their enzymatic activities. These unique ADHs have exquisite substrate specificity, unusual metal requirements, and an unprecedented monomeric quaternary structure. Further, sequence analysis shows that these ADHs form a monophyletic group along with additional family members encoded by putative phosphonate biosynthetic gene clusters. Thus, the reduction of phosphonoacetaldehyde to hydroxyethyl-phosphonate may represent a common step in the biosynthesis of many phosphonate natural products, a finding that lends insight into the evolution of phosphonate biosynthetic pathways and the chemical structures of new C–P containing secondary metabolites. PMID:18544530

Shao, Zengyi; Blodgett, Joshua A. V.; Circello, Benjamin T.; Eliot, Andrew C.; Woodyer, Ryan; Li, Gongyong; van der Donk, Wilfred A.; Metcalf, William W.; Zhao, Huimin

2008-01-01

158

Maintaining thermogenesis in cold exposed humans: relying on multiple metabolic pathways.  

PubMed

In cold exposed humans, increasing thermogenic rate is essential to prevent decreases in core temperature. This review describes the metabolic requirements of thermogenic pathways, mainly shivering thermogenesis, the largest contributor of heat. Research has shown that thermogenesis is sustained from a combination of carbohydrates, lipids, and proteins. The mixture of fuels is influenced by shivering intensity and pattern as well as by modifications in energy reserves and nutritional status. To date, there are no indications that differences in the types of fuel being used can alter shivering and overall heat production. We also bring forth the potential contribution of nonshivering thermogenesis in adult humans via the activation of brown adipose tissue (BAT) and explore some means to stimulate the activity of this highly thermogenic tissue. Clearly, the potential role of BAT, especially in young lean adults, can no longer be ignored. However, much work remains to clearly identify the quantitative nature of this tissue's contribution to total thermogenic rate and influence on shivering thermogenesis. Identifying ways to potentiate the effects of BAT via cold acclimation and/or the ingestion of compounds that stimulate the thermogenic process may have important implications in cold endurance and survival. PMID:25428848

Blondin, Denis P; Tingelstad, Hans Christian; Mantha, Olivier L; Gosselin, Chantal; Haman, François

2014-10-01

159

Yap1, transcription regulator in the Hippo signaling pathway, is required for Xenopus limb bud regeneration.  

PubMed

The Hippo signaling pathway is conserved from insects to mammals and is important for multiple processes, including cell proliferation, apoptosis and tissue homeostasis. Hippo signaling is also crucial for regeneration, including intercalary regeneration, of the whole body in the flatworm and of the leg in the cricket. However, its role in vertebrate epimorphic regeneration is unknown. Therefore, to identify principles of regeneration that are conserved among bilaterians, we investigated the role of Hippo signaling in the limb bud regeneration of an anuran amphibian, Xenopus laevis. We found that a transcription factor, Yap1, an important downstream effector of Hippo signaling, is upregulated in the regenerating limb bud. To evaluate Yap1?s function in limb bud regeneration, we made transgenic animals that expressed a dominant-negative form of Yap under a heat-shock promoter. Overexpression of a dominant-negative form of Yap in tadpoles reduced cell proliferation, induced ectopic apoptosis, perturbed the expression domains of limb-patterning genes including hoxa13, hoxa11, and shh in the regenerating limb bud. Transient expression of a dominant-negative Yap in transgenic tadpoles also caused limb bud regeneration defects, and reduced intercalary regeneration. These results indicate that Yap1 has a crucial role in controlling the limb regenerative capacity in Xenopus, and suggest that the involvement of Hippo signaling in regeneration is conserved between vertebrates and invertebrates. This finding provides molecular evidence that common principles underlie regeneration across phyla, and may contribute to the development of new therapies in regenerative medicine. PMID:24491818

Hayashi, Shinichi; Tamura, Koji; Yokoyama, Hitoshi

2014-04-01

160

Cell discarding policies supporting multiple delay and loss requirements in ATM networks  

Microsoft Academic Search

Future ATM networks will carry a wide range of applications which could differ significantly in their delay and loss requirements. In such an environment, supporting multiple delay requirements as well as loss requirements becomes indispensable to the priority mechanisms such as cell discarding policies employed in ATM switches. Traditional cell discarding policies, such as last-in-first-out (LIFO), pushout, threshold, and QoS

Yinggang Xie; Tao Yang

1997-01-01

161

Differential Effects of Multiplicity of Infection on Helicobacter pylori Induced Signaling Pathways and Interleukin8 Gene Transcription  

Microsoft Academic Search

Interleukin-8 (IL-8) plays a central role in the pathogenesis of Helicobacter pylori infection. We used four different H. pylori strains isolated from patients with gastritis or duodenal ulcer disease to examine their differential effects on signaling\\u000a pathways and IL-8 gene response in gastric epithelial cells. IL-8 mRNA level is elevated in response to high (100) multiplicity\\u000a of infection (MOI) independent

Birgit Ritter; Petra Kilian; Marc Rene Reboll; Klaus Resch; Johanna Kay DiStefano; Ronald Frank; Winfried Beil; Mahtab Nourbakhsh

2011-01-01

162

MRI of optic nerve and postchiasmal visual pathways and visual evoked potentials in secondary progressive multiple sclerosis  

Microsoft Academic Search

We studied the relationship between abnormalities shown by MRI and functional disturbances in the visual pathway as assessed\\u000a by the visual evoked potential (VEP) in 25 patients with established multiple sclerosis (MS); only 4 of whom had a history\\u000a of acute optic neuritis. Optic nerve MRI was abnormal in 19 (76 %) and is thus useful in detecting subclinical disease.

M. B. Davies; R. Williams; N. Haq; L. Pelosi; C. P. Hawkins

1998-01-01

163

Vps41p Function in the Alkaline Phosphatase Pathway Requires Homo-oligomerization and Interaction with AP3 through Two Distinct Domains  

Microsoft Academic Search

Transport of proteins through the ALP (alkaline phosphatase) pathway to the vacuole requires the function of the AP-3 adaptor complex and Vps41p. However, unlike other adaptor protein- dependent pathways, the ALP pathway has not been shown to require additional accessory proteins or coat proteins, such as membrane recruitment factors or clathrin. Two independent genetic approaches have been used to identify

Tamara Darsow; David J. Katzmann; Christopher R. Cowles; Scott D. Emr

2001-01-01

164

The MRN-CtIP pathway is required for metaphase chromosome alignment  

PubMed Central

Summary Faithful duplication of the genome in S phase followed by its accurate segregation in mitosis is essential to maintain genomic integrity. Recent studies have suggested that proteins involved in DNA transactions are also required for whole chromosome stability. Here we demonstrate that the MRN (Mre11, Rad50, and Nbs1) complex and CtIP are required for accurate chromosome segregation. Depletion of Mre11 or CtIP, antibody-mediated inhibition of Mre11, or small molecule inhibition of MRN using mirin results in metaphase chromosome alignment defects in Xenopus egg extracts. Similarly, loss of MRN function adversely affects spindle assembly around DNA-coated beads in egg extracts. Inhibition of MRN function in mammalian cells triggers a metaphase delay and disrupts the RCC1-dependent RanGTP gradient. Addition of the Mre11 inhibitor mirin to egg extracts and mammalian cells reduces RCC1 association with mitotic chromosomes. Thus, the MRN-CtIP pathway contributes to Ran-dependent mitotic spindle assembly by modulating RCC1 chromosome association. PMID:23434370

Rozier, Lorene; Guo, Yige; Peterson, Shaun; Sato, Mai; Baer, Richard; Gautier, Jean; Mao, Yinghui

2013-01-01

165

The MRN-CtIP pathway is required for metaphase chromosome alignment.  

PubMed

Faithful duplication of the genome in S phase followed by its accurate segregation in mitosis is essential to maintain genomic integrity. Recent studies have suggested that proteins involved in DNA transactions are also required for whole-chromosome stability. Here we demonstrate that the MRN (Mre11, Rad50, and Nbs1) complex and CtIP are required for accurate chromosome segregation. Depletion of Mre11 or CtIP, antibody-mediated inhibition of Mre11, or small-molecule inhibition of MRN using mirin results in metaphase chromosome alignment defects in Xenopus egg extracts. Similarly, loss of MRN function adversely affects spindle assembly around DNA-coated beads in egg extracts. Inhibition of MRN function in mammalian cells triggers a metaphase delay and disrupts the RCC1-dependent RanGTP gradient. Addition of the Mre11 inhibitor mirin to egg extracts and mammalian cells reduces RCC1 association with mitotic chromosomes. Thus, the MRN-CtIP pathway contributes to Ran-dependent mitotic spindle assembly by modulating RCC1 chromosome association. PMID:23434370

Rozier, Lorene; Guo, Yige; Peterson, Shaun; Sato, Mai; Baer, Richard; Gautier, Jean; Mao, Yinghui

2013-03-28

166

Yvh1 is required for a late maturation step in the 60S biogenesis pathway  

PubMed Central

Before entering translation, preribosomal particles undergo sequential late maturation steps. In the case of pre-60S particles, these steps involve the release of shuttling maturation factors and transport receptors. In this study, we report a new maturation step in the 60S biogenesis pathway in budding yeast. We show that efficient release of the nucleolar/nuclear ribosomal-like protein Mrt4 (homologous to the acidic ribosomal P-protein Rpp0) from pre-60S particles requires the highly conserved protein Yvh1, which associates only with late pre-60S particles. Cell biological and biochemical analyses reveal that Mrt4 fails to dissociate from late pre-60S particles in yvh1? cells, inducing a delay in nuclear pre–ribosomal RNA processing and a pre-60S export defect in yvh1? cells. Moreover, we have isolated gain of function alleles of Mrt4 that specifically bypass the requirement for Yvh1 and rescue all yvh1?-associated phenotypes. Together, our data suggest that Yvh1-mediated release of Mrt4 precedes cytoplasmic loading of Rpp0 on pre-60S particles and is an obligatory late step toward construction of translation-competent 60S subunits. PMID:19797079

Kemmler, Stefan; Occhipinti, Laura; Veisu, Maria

2009-01-01

167

Annexin II-dependent actin remodelling evoked by hydrogen peroxide requires the metalloproteinase/sphingolipid pathway  

PubMed Central

Actin remodeling is a dynamic process associated with cell shape modification occurring during cell cycle and proliferation. Oxidative stress plays a role in actin reorganization via various systems including p38MAPK. Beside, the mitogenic response evoked by hydrogen peroxide (H2O2) in fibroblasts and smooth muscle cells (SMC) involves the metalloproteinase (MMPs)/sphingomyelinase 2 (nSMase2) signaling pathway. The aim of this work was to investigate whether this system plays a role in actin remodeling induced by H2O2. Low H2O2 dose (5 µM) rapidly triggered a signaling cascade leading to nSMase2 activation, src and annexin 2 (AnxA2) phosphorylation, and actin remodeling, in fibroblasts and SMC. These events were blocked by pharmacological inhibitors of MMPs (Ro28-2653) and p38MAPK (SB203580), and were lacking in MMP2?/? and in nSMase2-mutant (fro) fibroblasts. Likewise, H2O2 was unable to induce actin remodeling in fro and MMP2?/? fibroblasts or in cells pretreated with p38MAPK, or MMP inhibitors. Finally we show that nSMase2 activation by H2O2, depends on MMP2 and p38MAPK, and is required for the src-dependent phosphorylation of AnxA2, and actin remodeling. Taken together, these findings indicate for the first time that AnxA2 phosphorylation and actin remodeling evoked by oxidative stress depend on the sphingolipid pathway, via MMP2 and p38MAPK. PMID:25574848

Cinq-Frais, Christel; Coatrieux, Christelle; Savary, Aude; D’Angelo, Romina; Bernis, Corinne; Salvayre, Robert; Nègre-Salvayre, Anne; Augé, Nathalie

2014-01-01

168

Pituitary Adenylate Cyclase-activating Polypeptide (PACAP)/PAC1HOP1 Receptor Activation Coordinates Multiple Neurotrophic Signaling Pathways  

PubMed Central

MAPK and Akt pathways are predominant mediators of trophic signaling for many neuronal systems. Among the vasoactive intestinal peptide/secretin/glucagon family of related peptides, pituitary adenylate cyclase-activating polypeptide (PACAP) binding to specific PAC1 receptor isoforms can engage multiple signaling pathways and promote neuroprotection through mechanisms that are not well understood. Using a primary sympathetic neuronal system, the current studies demonstrate that PACAP activation of PAC1HOP1 receptors engages both MAPK and Akt neurotrophic pathways in an integrated program to facilitate neuronal survival after growth factor withdrawal. PACAP not only stimulated prosurvival ERK1/2 and ERK5 activation but also abrogated SAPK/JNK and p38 MAPK signaling in parallel. In contrast to the potent and rapid effects of PACAP in ERK1/2 phosphorylation, PACAP stimulated Akt phosphorylation in a late phase of PAC1HOP1 receptor signaling. From inhibitor and immunoprecipitation analyses, the PACAP/PAC1HOP1 receptor-mediated Akt responses did not represent transactivation mechanisms but appeared to depend on G?q/phosphatidylinositol 3-kinase ? activity and vesicular internalization pathways. Phosphatidylinositol 3-kinase ?-selective inhibitors blocked PACAP-stimulated Akt phosphorylation in primary neuronal cultures and in PAC1HOP1-overexpressing cell lines; RNA interference-mediated knockdown of the receptor effectors attenuated PACAP-mediated Akt activation. Similarly, perturbation of endocytic pathways also blocked Akt phosphorylation. Between ERK and Akt pathways, PACAP-stimulated Akt signaling was the primary cascade that attenuated cultured neuron apoptosis after growth factor withdrawal. The partitioning of PACAP-mediated Akt signaling in endosomes may be a key mechanism contributing to the high spatial and temporal specificity in signal transduction necessary for survival pathways. PMID:20093365

May, Victor; Lutz, Eve; MacKenzie, Christopher; Schutz, Kristin C.; Dozark, Kate; Braas, Karen M.

2010-01-01

169

The Root Hair Assay Facilitates the Use of Genetic and Pharmacological Tools in Order to Dissect Multiple Signalling Pathways That Lead to Programmed Cell Death  

PubMed Central

The activation of programmed cell death (PCD) is often a result of complex signalling pathways whose relationship and intersection are not well understood. We recently described a PCD root hair assay and proposed that it could be used to rapidly screen genetic or pharmacological modulators of PCD. To further assess the applicability of the root hair assay for studying multiple signalling pathways leading to PCD activation we have investigated the crosstalk between salicylic acid, autophagy and apoptosis-like PCD (AL-PCD) in Arabidopsis thaliana. The root hair assay was used to determine rates of AL-PCD induced by a panel of cell death inducing treatments in wild type plants treated with chemical modulators of salicylic acid synthesis or autophagy, and in genetic lines defective in autophagy or salicylic acid signalling. The assay demonstrated that PCD induced by exogenous salicylic acid or fumonisin B1 displayed a requirement for salicylic acid signalling and was partially dependent on the salicylic acid signal transducer NPR1. Autophagy deficiency resulted in an increase in the rates of AL-PCD induced by salicylic acid and fumonisin B1, but not by gibberellic acid or abiotic stress. The phenylalanine ammonia lyase-dependent salicylic acid synthesis pathway contributed only to death induced by salicylic acid and fumonisin B1. 3-Methyladenine, which is commonly used as an inhibitor of autophagy, appeared to influence PCD induction in all treatments suggesting a possible secondary, non-autophagic, effect on a core component of the plant PCD pathway. The results suggest that salicylic acid signalling is negatively regulated by autophagy during salicylic acid and mycotoxin-induced AL-PCD. However, this crosstalk does not appear to be directly involved in PCD induced by gibberellic acid or abiotic stress. This study demonstrates that the root hair assay is an effective tool for relatively rapid investigation of complex signalling pathways leading to the activation of PCD. PMID:24755572

Kacprzyk, Joanna; Devine, Aoife; McCabe, Paul F.

2014-01-01

170

Gene expression profiles from discordant monozygotic twins suggest that molecular pathways are shared among multiple systemic autoimmune diseases  

PubMed Central

Introduction The objective of this study is to determine if multiple systemic autoimmune diseases (SAID) share gene expression pathways that could provide insights into pathogenic mechanisms common to these disorders. Methods RNA microarray analyses (Agilent Human 1A(V2) 20K oligo arrays) were used to quantify gene expression in peripheral blood cells from 20 monozygotic (MZ) twin pairs discordant for SAID. Six affected probands with systemic lupus erythematosus (SLE), six with rheumatoid arthritis (RA), eight with idiopathic inflammatory myopathies (IIM), and their same-gendered unaffected twins, were enrolled. Comparisons were made between discordant twin pairs and these were also each compared to 40 unrelated control subjects (matched 2:1 to each twin by age, gender and ethnicity) using statistical and molecular pathway analyses. Relative quantitative PCR was used to verify independently measures of differential gene expression assessed by microarray analysis. Results Probands and unrelated, matched controls differed significantly in gene expression for 104 probes corresponding to 92 identifiable genes (multiple-comparison adjusted P values < 0.1). Differentially expressed genes involved several overlapping pathways including immune responses (16%), signaling pathways (24%), transcription/translation regulators (26%), and metabolic functions (15%). Interferon (IFN)-response genes (IFI27, OASF, PLSCR1, EIF2AK2, TNFAIP6, and TNFSF10) were up-regulated in probands compared to unrelated controls. Many of the abnormally expressed genes played regulatory roles in multiple cellular pathways. We did not detect any probes expressed differentially in comparisons among the three SAID phenotypes. Similarly, we found no significant differences in gene expression when comparing probands to unaffected twins or unaffected twins to unrelated controls. Gene expression levels for unaffected twins appeared intermediate between that of probands and unrelated controls for 6535 probes (32% of the total probes) as would be expected by chance. By contrast, in unaffected twins intermediate ordering was observed for 84 of the 104 probes (81%) whose expression differed significantly between probands and unrelated controls. Conclusions Alterations in expression of a limited number of genes may influence the dysregulation of numerous, integrated immune response, cell signaling and regulatory pathways that are common to a number of SAID. Gene expression profiles in peripheral blood suggest that for genes in these critical pathways, unaffected twins may be in a transitional or intermediate state of immune dysregulation between twins with SAID and unrelated controls, perhaps predisposing them to the development of SAID given the necessary and sufficient environmental exposures. PMID:21521520

2011-01-01

171

Autocrine prolactin induced by the Pten–Akt pathway is required for lactation initiation and provides a direct link between the Akt and Stat5 pathways  

PubMed Central

Extrapituitary prolactin (Prl) is produced in humans and rodents; however, little is known about its in vivo regulation or physiological function. We now report that autocrine prolactin is required for terminal mammary epithelial differentiation during pregnancy and that its production is regulated by the Pten–PI3K–Akt pathway. Conditional activation of the PI3K–Akt pathway in the mammary glands of virgin mice by either Akt1 expression or Pten deletion rapidly induced terminal mammary epithelial differentiation accompanied by the synthesis of milk despite the absence of lobuloalveolar development. Surprisingly, we found that mammary differentiation was due to the PI3K–Akt-dependent synthesis and secretion of autocrine prolactin and downstream activation of the prolactin receptor (Prlr)–Jak–Stat5 pathway. Consistent with this, Akt-induced mammary differentiation was abrogated in Prl?/?, Prlr?/?, and Stat5?/? mice. Furthermore, cells treated with conditioned medium from mammary glands in which Akt had been activated underwent rapid Stat5 phosphorylation in a manner that was blocked by inhibition of Jak2, treatment with an anti-Prl antibody, or deletion of the prolactin gene. Demonstrating a physiological requirement for autocrine prolactin, mammary glands from lactation-defective Akt1?/?;Akt2+/? mice failed to express autocrine prolactin or activate Stat5 during late pregnancy despite normal levels of circulating serum prolactin and pituitary prolactin production. Our findings reveal that PI3K–Akt pathway activation is necessary and sufficient to induce autocrine prolactin production in the mammary gland, Stat5 activation, and terminal mammary epithelial differentiation, even in the absence of the normal developmental program that prepares the mammary gland for lactation. Together, these findings identify a function for autocrine prolactin during normal development and demonstrate its endogenous regulation by the PI3K–Akt pathway. PMID:23028142

Chen, Chien-Chung; Stairs, Douglas B.; Boxer, Robert B.; Belka, George K.; Horseman, Nelson D.; Alvarez, James V.; Chodosh, Lewis A.

2012-01-01

172

GATA4 knockdown in MA-10 Leydig cells identifies multiple target genes in the steroidogenic pathway.  

PubMed

GATA4 is an essential transcription factor required for the initiation of genital ridge formation, for normal testicular and ovarian differentiation at the time of sex determination, and for male and female fertility in adulthood. In spite of its crucial roles, the genes and/or gene networks that are ultimately regulated by GATA4 in gonadal tissues remain to be fully understood. This is particularly true for the steroidogenic lineages such as Leydig cells of the testis where many in vitro (promoter) studies have provided good circumstantial evidence that GATA4 is a key regulator of Leydig cell gene expression and steroidogenesis, but formal proof is still lacking. We therefore performed a microarray screening analysis of MA-10 Leydig cells in which Gata4 expression was knocked down using an siRNA strategy. Analysis identified several GATA4-regulated pathways including cholesterol synthesis, cholesterol transport, and especially steroidogenesis. A decrease in GATA4 protein was associated with decreased expression of steroidogenic genes previously suspected to be GATA4 targets such as Cyp11a1 and Star. Gata4 knockdown also led to an important decrease in other novel steroidogenic targets including Srd5a1, Gsta3, Hsd3b1, and Hsd3b6, as well as genes known to participate in cholesterol metabolism such as Scarb1, Ldlr, Soat1, Scap, and Cyp51. Consistent with the decreased expression of these genes, a reduction in GATA4 protein compromised the ability of MA-10 cells to produce steroids both basally and under hormone stimulation. These data therefore provide strong evidence that GATA4 is an essential transcription factor that sits atop of the Leydig cell steroidogenic program. PMID:25504870

Bergeron, Francis; Nadeau, Gabriel; S Viger, Robert

2015-03-01

173

mir-30d Regulates multiple genes in the autophagy pathway and impairs autophagy process in human cancer cells  

SciTech Connect

Highlights: ? Gene set enrichment analysis indicated mir-30d might regulate the autophagy pathway. ? mir-30d represses the expression of BECN1, BNIP3L, ATG12, ATG5 and ATG2. ? BECN1, BNIP3L, ATG12, ATG5 and ATG2 are direct targets of mir-30d. ? mir-30d inhibits autophagosome formation and LC3B-I conversion to LC3B-II. ? mir-30d regulates the autophagy process. -- Abstract: In human epithelial cancers, the microRNA (miRNA) mir-30d is amplified with high frequency and serves as a critical oncomir by regulating metastasis, apoptosis, proliferation, and differentiation. Autophagy, a degradation pathway for long-lived protein and organelles, regulates the survival and death of many cell types. Increasing evidence suggests that autophagy plays an important function in epithelial tumor initiation and progression. Using a combined bioinformatics approach, gene set enrichment analysis, and miRNA target prediction, we found that mir-30d might regulate multiple genes in the autophagy pathway including BECN1, BNIP3L, ATG12, ATG5, and ATG2. Our further functional experiments demonstrated that the expression of these core proteins in the autophagy pathway was directly suppressed by mir-30d in cancer cells. Finally, we showed that mir-30d regulated the autophagy process by inhibiting autophagosome formation and LC3B-I conversion to LC3B-II. Taken together, our results provide evidence that the oncomir mir-30d impairs the autophagy process by targeting multiple genes in the autophagy pathway. This result will contribute to understanding the molecular mechanism of mir-30d in tumorigenesis and developing novel cancer therapy strategy.

Yang, Xiaojun [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States) [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Department of General Surgery, Gansu Provincial Hospital, Lanzhou, Gansu 710000 (China); Zhong, Xiaomin [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States) [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Obstetrics and Gynecology Hospital, Fudan University, Shanghai 200011 (China); Tanyi, Janos L.; Shen, Jianfeng [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States)] [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States); Xu, Congjian [Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Obstetrics and Gynecology Hospital, Fudan University, Shanghai 200011 (China)] [Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Obstetrics and Gynecology Hospital, Fudan University, Shanghai 200011 (China); Gao, Peng [Department of General Surgery, Gansu Provincial Hospital, Lanzhou, Gansu 710000 (China)] [Department of General Surgery, Gansu Provincial Hospital, Lanzhou, Gansu 710000 (China); Zheng, Tim M. [Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104 (United States)] [Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104 (United States); DeMichele, Angela [Division of Hematology and Oncology, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104 (United States)] [Division of Hematology and Oncology, Department of Medicine, University of Pennsylvania, Philadelphia, PA 19104 (United States); Zhang, Lin, E-mail: linzhang@mail.med.upenn.edu [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States)] [Ovarian Cancer Research Center and Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, PA 19104 (United States)

2013-02-15

174

Ras pathways in Caenorhabditis elegans  

Microsoft Academic Search

The let-60 ras gene of Caenorhabditis elegans is required for multiple aspects of development. The vulval differentiation pathway is the most intensively studied of these, but the ras pathway has now been shown to also be essential for male spicule development. Using vulval differentiation, molecular genetic techniques are now being used to study structure\\/function relationships of particular signaling components and

Paul S. Kayne; Paul W. Sternberg

1995-01-01

175

Selective inhibitor of endosomal trafficking pathways exploited by multiple toxins and viruses.  

PubMed

Pathogenic microorganisms and toxins have evolved a variety of mechanisms to gain access to the host-cell cytosol and thereby exert virulent effects upon the host. One common mechanism of cellular entry requires trafficking to an acidified endosome, which promotes translocation across the host membrane. To identify small-molecule inhibitors that block this process, a library of 30,000 small molecules was screened for inhibitors of anthrax lethal toxin. Here we report that 4-bromobenzaldehyde N-(2,6-dimethylphenyl)semicarbazone, the most active compound identified in the screen, inhibits intoxication by lethal toxin and blocks the entry of multiple other acid-dependent bacterial toxins and viruses into mammalian cells. This compound, which we named EGA, also delays lysosomal targeting and degradation of the EGF receptor, indicating that it targets host-membrane trafficking. In contrast, EGA does not block endosomal recycling of transferrin, retrograde trafficking of ricin, phagolysosomal trafficking, or phagosome permeabilization by Franciscella tularensis. Furthermore, EGA does not neutralize acidic organelles, demonstrating that its mechanism of action is distinct from pH-raising agents such as ammonium chloride and bafilomycin A1. EGA is a powerful tool for the study of membrane trafficking and represents a class of host-targeted compounds for therapeutic development to treat infectious disease. PMID:24191014

Gillespie, Eugene J; Ho, Chi-Lee C; Balaji, Kavitha; Clemens, Daniel L; Deng, Gang; Wang, Yao E; Elsaesser, Heidi J; Tamilselvam, Batcha; Gargi, Amandeep; Dixon, Shandee D; France, Bryan; Chamberlain, Brian T; Blanke, Steven R; Cheng, Genhong; de la Torre, Juan Carlos; Brooks, David G; Jung, Michael E; Colicelli, John; Damoiseaux, Robert; Bradley, Kenneth A

2013-12-10

176

Selective inhibitor of endosomal trafficking pathways exploited by multiple toxins and viruses  

PubMed Central

Pathogenic microorganisms and toxins have evolved a variety of mechanisms to gain access to the host-cell cytosol and thereby exert virulent effects upon the host. One common mechanism of cellular entry requires trafficking to an acidified endosome, which promotes translocation across the host membrane. To identify small-molecule inhibitors that block this process, a library of 30,000 small molecules was screened for inhibitors of anthrax lethal toxin. Here we report that 4-bromobenzaldehyde N-(2,6-dimethylphenyl)semicarbazone, the most active compound identified in the screen, inhibits intoxication by lethal toxin and blocks the entry of multiple other acid-dependent bacterial toxins and viruses into mammalian cells. This compound, which we named EGA, also delays lysosomal targeting and degradation of the EGF receptor, indicating that it targets host-membrane trafficking. In contrast, EGA does not block endosomal recycling of transferrin, retrograde trafficking of ricin, phagolysosomal trafficking, or phagosome permeabilization by Franciscella tularensis. Furthermore, EGA does not neutralize acidic organelles, demonstrating that its mechanism of action is distinct from pH-raising agents such as ammonium chloride and bafilomycin A1. EGA is a powerful tool for the study of membrane trafficking and represents a class of host-targeted compounds for therapeutic development to treat infectious disease. PMID:24191014

Gillespie, Eugene J.; Ho, Chi-Lee C.; Balaji, Kavitha; Clemens, Daniel L.; Deng, Gang; Wang, Yao E.; Elsaesser, Heidi J.; Tamilselvam, Batcha; Gargi, Amandeep; Dixon, Shandee D.; France, Bryan; Chamberlain, Brian T.; Blanke, Steven R.; Cheng, Genhong; de la Torre, Juan Carlos; Brooks, David G.; Jung, Michael E.; Colicelli, John; Damoiseaux, Robert; Bradley, Kenneth A.

2013-01-01

177

Determining the elastic properties of aptamer-ricin single molecule multiple pathway interactions  

NASA Astrophysics Data System (ADS)

We report on the elastic properties of ricin and anti-ricin aptamer interactions, which showed three stable binding conformations, each of which has its special elastic properties. These different unbinding pathways were investigated by the dynamic force spectroscopy. A series-spring model combining the worm-like-chain model and Hook's law was used to estimate the apparent spring constants of the aptamer and linker molecule polyethylene glycol. The aptamer in its three different unbinding pathways showed different apparent spring constants. The two reaction barriers in the unbinding pathways also influence the apparent spring constant of the aptamer. This special elastic behavior of aptamer was used to distinguish its three unbinding pathways under different loading rates. This method also offered a way to distinguish and discard the non-specific interactions in single molecule experiments.

Wang, Bin; Park, Bosoon; Kwon, Yongkuk; Xu, Bingqian

2014-05-01

178

Simultaneous Reconstruction of Multiple Signaling Pathways via the Prize-Collecting Steiner Forest Problem  

E-print Network

Signaling networks are essential for cells to control processes such as growth and response to stimuli. Although many “omic” data sources are available to probe signaling pathways, these data are typically sparse and noisy. ...

Tuncbag, Nurcan

179

WNT/beta-catenin pathway activation in Wilms tumors: a unifying mechanism with multiple entries?  

PubMed

Based on characterization of both genomic and expression status of WT1 and CTNNB1 (beta-catenin) in a series of 60 Wilms tumor samples, combined with genome-wide expression profiling of these tumors, normal mature and fetal kidney controls, we show that WT1/beta-catenin expression was a better classifier than WT1/CTNNB1 mutations. We present molecular data supporting that the WNT pathway is involved in both tumor classes, with and without WT1/beta-catenin alterations. In the tumor class with WT1/beta-catenin alterations, we identified overexpression of 14 previously unreported WNT target genes, including TWIST1. We show that the TWIST1 protein was specifically expressed in these tumors, where staining was restricted to the stromal, nuclear beta-catenin positive, component. By comparing the state of the WNT pathway in tumors without WT1/beta-catenin alterations and fetal kidneys we provide evidence that suggests that these tumors have a heightened level of pathway activation. We characterized mutations of the WNT pathway regulator gene WTX in 16% of this tumor class. Moreover, genome-transcriptome correlation analysis allowed us to identify three other WNT pathway regulator genes that could participate in the activation of the WNT pathway: BCL9 (1p36.2), CTNNBIP1 (1p36.2), and CBY1 (22q13.1). These genes thus represent new potential important actors in WT tumorigenesis. PMID:19530245

Corbin, Marie; de Reyniès, Aurélien; Rickman, David S; Berrebi, Dominique; Boccon-Gibod, Liliane; Cohen-Gogo, Sarah; Fabre, Monique; Jaubert, Francis; Faussillon, Marine; Yilmaz, Funda; Sarnacki, Sabine; Landman-Parker, Judith; Patte, Catherine; Schleiermacher, Gudrun; Antignac, Corinne; Jeanpierre, Cécile

2009-09-01

180

TNIK is required for postsynaptic and nuclear signalling pathways and cognitive function  

PubMed Central

Traf2 and NcK interacting Kinase (TNiK) contains serine-threonine kinase and scaffold domains and has been implicated in cell proliferation and glutamate receptor regulation in vitro. Here we report its role in vivo using mice carrying a knockout mutation. TNiK binds protein complexes in the synapse linking it to the NMDA receptor (NMDAR) via AKAP9. NMDAR and metabotropic receptors bidirectionally regulate TNiK phosphorylation and TNiK was required for AMPA expression and synaptic function. TNiK also organises nuclear complexes and in the absence of TNiK, there was a marked elevation in GSK3? and phosphorylation levels of its cognate phosphorylation sites on NeuroD1 with alterations in Wnt pathway signalling. We observed impairments in dentate gyrus neurogenesis in TNiK knockout mice and cognitive testing using the touchscreen apparatus revealed impairments in pattern separation on a test of spatial discrimination. Object-location paired associates learning, which is dependent on glutamatergic signalling was also impaired. Additionally, TNiK knockout mice displayed hyperlocomotor behavior that could be rapidly reversed by GSK3? inhibitors, indicating the potential for pharmacological rescue of a behavioral phenotype. These data establish TNiK as a critical regulator of cognitive functions and suggest it may play a regulatory role in diseases impacting on its interacting proteins and complexes. PMID:23035106

Coba, M.P.; Komiyama, N.H.; Nithianantharajah, J.; Kopanitsa, M.V.; Indersmitten, T.; Skene, N.G.; Tuck, E.J.; Fricker, D.G.; Elsegood, K.A.; Stanford, L.E.; Afinowi, N.; Saksida, L.M.; Bussey, T.J.; O’Dell, T.J.; Grant, S.G.N.

2014-01-01

181

Autonomous basin climbing method with sampling of multiple transition pathways: application to anisotropic diffusion of point defects in hcp Zr  

NASA Astrophysics Data System (ADS)

This paper presents an extension of the autonomous basin climbing (ABC) method, an atomistic activation-relaxation technique for sampling transition-state pathways. The extended algorithm (ABC-E) allows the sampling of multiple transition pathways from a given minimum, with the additional feature of identifying the pathways in the order of increasing activation barriers, thereby prioritizing them according to their importance in the kinetics. Combined with on-the-fly kinetic Monte Carlo calculations, the method is applied to simulate the anisotropic diffusion of point defects in hcp Zr. Multiple migration mechanisms are identified for both the interstitials and vacancies, and benchmarked against results from other methods in the literature. The self-interstitial atom (SIA) diffusion kinetics shows a maximum anisotropy at intermediate temperatures (400~700?K), a non-monotonic behavior that we explain to originate from the stabilities and migration mechanisms associated with different SIA sites. The accuracy of the ABC-E calculations is validated, in part, by the existing results in the literature for point defect diffusion in hcp Zr, and by benchmarking against analytical results on a hypothetical rough-energy landscape. Lastly, sampling prioritization and computational efficiency are demonstrated through a direct comparison between the ABC-E and the activation relaxation technique.

Fan, Yue; Yip, Sidney; Yildiz, Bilge

2014-09-01

182

Autonomous basin climbing method with sampling of multiple transition pathways: application to anisotropic diffusion of point defects in hcp Zr.  

PubMed

This paper presents an extension of the autonomous basin climbing (ABC) method, an atomistic activation-relaxation technique for sampling transition-state pathways. The extended algorithm (ABC-E) allows the sampling of multiple transition pathways from a given minimum, with the additional feature of identifying the pathways in the order of increasing activation barriers, thereby prioritizing them according to their importance in the kinetics. Combined with on-the-fly kinetic Monte Carlo calculations, the method is applied to simulate the anisotropic diffusion of point defects in hcp Zr. Multiple migration mechanisms are identified for both the interstitials and vacancies, and benchmarked against results from other methods in the literature. The self-interstitial atom (SIA) diffusion kinetics shows a maximum anisotropy at intermediate temperatures (400~700 K), a non-monotonic behavior that we explain to originate from the stabilities and migration mechanisms associated with different SIA sites. The accuracy of the ABC-E calculations is validated, in part, by the existing results in the literature for point defect diffusion in hcp Zr, and by benchmarking against analytical results on a hypothetical rough-energy landscape. Lastly, sampling prioritization and computational efficiency are demonstrated through a direct comparison between the ABC-E and the activation relaxation technique. PMID:25134625

Fan, Yue; Yip, Sidney; Yildiz, Bilge

2014-09-10

183

Integration of multiple signaling pathway activities resolves K-RAS/N-RAS mutation paradox in colon epithelial cell response to inflammatory cytokine stimulation  

E-print Network

Colon tumors frequently harbor mutation in K-RAS and/or N-RAS, members of a GTPase family operating as a central hub for multiple key signaling pathways. While these proteins are strongly homologous, they exhibit diverse ...

Kreeger, Pamela K.

184

Maximal adamantyl-substituted retinoid-related molecule-induced apoptosis requires NF-?B noncanonical and canonical pathway activation  

PubMed Central

NF-?B transcription factors have a critical role in regulating cell survival and apoptosis. We have previously shown that 4-(3-Cl-(1-adamantyl)-4-hydroxyphenyl)-3-chlorocinnamic acid (3-Cl-AHPC), an adamantyl-substituted retinoid molecule, induced apoptosis and required NF-?B activation in prostate and breast carcinoma cells. Here, we show that 3-Cl-AHPC activated both I?B kinase (IKK)? and IKK? with subsequent activation of the canonical and noncanonical NF-?B pathways in the human breast carcinoma and leukemia cell lines. 3-Cl-AHPC-mediated activation of the NF-?B canonical pathway occurred within 6?h, whereas maximal activation of the NF-?B noncanonical pathway required 48?h. Knockout of IKK? or IKK? expression in mouse embryonic fibroblast cells and knockdown of IKK? or IKK? in MDA-MB-468 cells resulted in the inhibition of 3-Cl-AHPC-mediated apoptosis, indicating that activation of canonical and noncanonical pathways are required for maximal 3-Cl-AHPC-mediated apoptosis. 3-Cl-AHPC activation of the noncanonical pathway was preceded by caspase-mediated decrease in the E3-ligase c-IAP1 with subsequent stabilization of NF-?B-inducing kinase (NIK) expression, increased binding of NIK by TRAF3, activation of IKK?, and the resultant increased levels of RelB and p52. Increased expression of c-IAP1 blocked 3-Cl-AHPC-mediated stabilization of NIK levels and 3-Cl-AHPC-mediated apoptosis. Cdc37 expression was required for activation of IKK? and IKK? by 3-Cl-AHPC. These findings suggest that NF-?B pathways have an important role in 3-Cl-AHPC-mediated apoptosis. PMID:20671747

Farhana, L; Dawson, M I; Murshed, F; Fontana, J A

2011-01-01

185

Arabidopsis Transcriptome Profiling Indicates That Multiple Regulatory Pathways Are Activated during Cold Acclimation in Addition to the CBF Cold Response PathwayW?  

PubMed Central

Many plants, including Arabidopsis, increase in freezing tolerance in response to low, nonfreezing temperatures, a phenomenon known as cold acclimation. Previous studies established that cold acclimation involves rapid expression of the CBF transcriptional activators (also known as DREB1 proteins) in response to low temperature followed by induction of the CBF regulon (CBF-targeted genes), which contributes to an increase in freezing tolerance. Here, we present the results of transcriptome-profiling experiments indicating the existence of multiple low-temperature regulatory pathways in addition to the CBF cold response pathway. The transcript levels of ?8000 genes were determined at multiple times after plants were transferred from warm to cold temperature and in warm-grown plants that constitutively expressed CBF1, CBF2, or CBF3. A total of 306 genes were identified as being cold responsive, with transcripts for 218 genes increasing and those for 88 genes decreasing threefold or more at one or more time points during the 7-day experiment. These results indicate that extensive downregulation of gene expression occurs during cold acclimation. Of the cold-responsive genes, 48 encode known or putative transcription factors. Two of these, RAP2.1 and RAP2.6, were activated by CBF expression and thus presumably control subregulons of the CBF regulon. Transcriptome comparisons indicated that only 12% of the cold-responsive genes are certain members of the CBF regulon. Moreover, at least 28% of the cold-responsive genes were not regulated by the CBF transcription factors, including 15 encoding known or putative transcription factors, indicating that these cold-responsive genes are members of different low-temperature regulons. Significantly, CBF expression at warm temperatures repressed the expression of eight genes that also were downregulated by low temperature, indicating that in addition to gene induction, gene repression is likely to play an integral role in cold acclimation. PMID:12172015

Fowler, Sarah; Thomashow, Michael F.

2002-01-01

186

The 3-Hydroxy-2-Butanone Pathway Is Required for Pectobacterium carotovorum Pathogenesis  

PubMed Central

Pectobacterium species are necrotrophic bacterial pathogens that cause soft rot diseases in potatoes and several other crops worldwide. Gene expression data identified Pectobacterium carotovorum subsp. carotovorum budB, which encodes the ?-acetolactate synthase enzyme in the 2,3-butanediol pathway, as more highly expressed in potato tubers than potato stems. This pathway is of interest because volatiles produced by the 2,3-butanediol pathway have been shown to act as plant growth promoting molecules, insect attractants, and, in other bacterial species, affect virulence and fitness. Disruption of the 2,3-butanediol pathway reduced virulence of P. c. subsp. carotovorum WPP14 on potato tubers and impaired alkalinization of growth medium and potato tubers under anaerobic conditions. Alkalinization of the milieu via this pathway may aid in plant cell maceration since Pectobacterium pectate lyases are most active at alkaline pH. PMID:21876734

Marquez-Villavicencio, Maria del Pilar; Weber, Brooke; Witherell, R. Andrews; Willis, David K.; Charkowski, Amy O.

2011-01-01

187

Enzyme activity demonstrates multiple pathways of innate immunity in Indo-Pacific anthozoans  

PubMed Central

Coral reefs are threatened by increasing levels of coral disease and the functional loss of obligate algal symbionts (bleaching). Levels of immunity relate directly to susceptibility to these threats; however, our understanding of fundamental aspects of coral immunology is lacking. We show that three melanin-synthesis pathway components (mono-phenoloxidase, ortho-diphenoloxidase (tyrosinase-type pathway) and para-diphenoloxidase (laccase-type pathway)) are present in both their active (phenoloxidase, PO) and inactive (prophenoloxidase, PPO) forms across a diverse range of 22 species of healthy Indo-Pacific anthozoans. We also demonstrate transglutaminase activity of the coagulation cascade for, to our knowledge, the first time in a coral. Melanin-synthesis enzyme activities varied among taxa, although they were generally lowest in the coral family Acroporidae and highest in the Poritidae and Oculinidae. Inactive tyrosinase-type activity (PPO) and active laccase-type activity (PO) correlate with taxonomic patterns in disease resistance, whereas the converse pattern in activity levels correlates with bleaching resistance. Overall, we demonstrate the presence of several melanin-synthesis pathways in Indo-Pacific corals, co-regulation among some pathway components, and highlight their potential roles in coral health. PMID:22810430

Palmer, C. V.; Bythell, J. C.; Willis, B. L.

2012-01-01

188

BDNF-mediated regulation of ethanol consumption requires the activation of the MAP kinase pathway and protein synthesis  

PubMed Central

We previously found that the brain-derived neurotrophic factor (BDNF) in the dorsolateral striatum (DLS) is part of a homeostatic pathway that gates ethanol self-administration [Jeanblanc et al. (2009). J Neurosci, 29, 13494–13502)]. Specifically, we showed that moderate levels (10%) of ethanol consumption increase BDNF expression within the DLS, and that direct infusion of BDNF into the DLS decreases operant self-administration of a 10% ethanol solution. BDNF binding to its receptor, TrkB, activates the mitogen-activated protein kinase (MAPK), phospholipase C-? (PLC-?) and phosphatidylinositol 3-kinase (PI3K) pathways. Thus, here, we set out to identify which of these intracellular pathway(s) plays a role in the regulation of ethanol consumption by BDNF. We found that inhibition of the MAPK, but not PLC-? or PI3K, activity blocks the BDNF-mediated reduction of ethanol consumption. As activation of the MAPK pathway leads to the initiation of transcription and/or translation events, we tested whether the BDNF-mediated reduction of ethanol self-administration requires de novo protein synthesis. We found that the inhibitory effect of BDNF on ethanol intake is blocked by the protein synthesis inhibitor cycloheximide. Together, our results show that BDNF attenuates ethanol drinking via activation of the MAPK pathway in a protein synthesis-dependent manner within the DLS. PMID:23189980

Jeanblanc, Jerome; Logrip, Marian L.; Janak, Patricia H.; Ron, Dorit

2013-01-01

189

Single-target RNA interference for the blockade of multiple interacting proinflammatory and profibrotic pathways in cardiac fibroblasts.  

PubMed

Therapeutic targets of broad relevance are likely located in pathogenic pathways common to disorders of various etiologies. Screening for targets of this type revealed CCN genes to be consistently upregulated in multiple cardiomyopathies. We developed RNA interference (RNAi) to silence CCN2 and found this single-target approach to block multiple proinflammatory and profibrotic pathways in activated primary cardiac fibroblasts (PCFBs). The RNAi-strategy was developed in murine PCFBs and then investigated in "individual" human PCFBs grown from human endomyocardial biopsies (EMBs). Screening of short hairpin RNA (shRNA) sequences for high silencing efficacy and specificity yielded RNAi adenovectors silencing CCN2 in murine or human PCFBs, respectively. Comparison of RNAi with CCN2-modulating microRNA (miR) vectors expressing miR-30c or miR-133b showed higher efficacy of RNAi. In murine PCFBs, CCN2 silencing resulted in strongly reduced expression of stretch-induced chemokines (Ccl2, Ccl7, Ccl8), matrix metalloproteinases (MMP2, MMP9), extracellular matrix (Col3a1), and a cell-to-cell contact protein (Cx43), suggesting multiple signal pathways to be linked to CCN2. Immune cell chemotaxis towards CCN2-depleted PCFBs was significantly reduced. We demonstrate here that this RNAi strategy is technically applicable to "individual" human PCFBs, too, but that these display individually strikingly different responses to CCN2 depletion. Either genomically encoded factors or stable epigenetic modification may explain different responses between individual PCFBs. The new RNAi approach addresses a key regulator protein induced in cardiomyopathies. Investigation of this and other molecular therapies in individual human PCBFs may help to dissect differential pathogenic processes between otherwise similar disease entities and individuals. PMID:24239602

Tank, Juliane; Lindner, Diana; Wang, Xiaomin; Stroux, Andrea; Gilke, Leona; Gast, Martina; Zietsch, Christin; Skurk, Carsten; Scheibenbogen, Carmen; Klingel, Karin; Lassner, Dirk; Kühl, Uwe; Schultheiss, Heinz-Peter; Westermann, Dirk; Poller, Wolfgang

2014-01-01

190

Multiple Genetic Alterations within the PI3K Pathway Are Responsible for AKT Activation in Patients with Ovarian Carcinoma  

PubMed Central

The phosphatidylinositol 3-kinase (PI3K)/AKT pathway is activated in multiple cancers including ovarian carcinoma (OC). However, the relative contribution of the single components within the PI3K pathway to AKT activation in OC is still unclear. We examined 98 tumor samples from Italian OC patients for alterations in the members of the PI3K pathway. We report that AKT is significantly hyperactive in OC compared to normal tissue (n?=?93; p<0.0001) and that AKT activation is preferentially observed in the elderly (>58 years old; n?=?93; p<0.05). The most frequent alteration is the overexpression of the p110? catalytic subunit of PI3K (63/93, ?68%); less frequent alterations comprise the loss of PTEN (24/89, 27%) and the overexpression of AKT1 (18/96, 19%) or AKT2 (11/88,12.5%). Mutations in the PIK3CA or KRAS genes were detected at lower frequency (12% and 10%, respectively) whereas mutations in AKT1 or AKT2 genes were absent. Although many tumors presented a single lesion (28/93, of which 23 overexpressed PIK3CA, 1 overexpressed AKT and 4 had lost PTEN), many OC (35/93) presented multiple alterations within the PI3K pathway. Apparently, aberrant PI3K signalling was mediated by activation of the canonical downstream AKT-dependent mTOR/S6K1/4EBP1 pathway and by regulation of expression of oncogenic transcription factors that include HMGA1, JUN-B, FOS and MYC but not by AKT-independent activation of SGK3. FISH analysis indicated that gene amplification of PIK3CA, AKT1 and AKT2 (but not of PI3KR1) and the loss of PTEN are common and may account for changes in the expression of the corresponding proteins. In conclusion, our results indicate that p110? overexpression represents the most frequent alteration within the PI3K/AKT pathway in OC. However, p110? overexpression may not be sufficient to activate AKT signalling and drive ovarian tumorigenesis since many tumors overexpressing PI3K presented at least one additional alteration. PMID:23408974

De Marco, Carmela; Rinaldo, Nicola; Bruni, Paola; Malzoni, Carmine; Zullo, Fulvio; Fabiani, Fernanda; Losito, Simona; Scrima, Marianna; Marino, Federica Zito; Franco, Renato; Quintiero, Alfina; Agosti, Valter; Viglietto, Giuseppe

2013-01-01

191

Gene expression profiles from discordant monozygotic twins suggest that molecular pathways are shared among multiple systemic autoimmune diseases  

Microsoft Academic Search

Introduction  The objective of this study is to determine if multiple systemic autoimmune diseases (SAID) share gene expression pathways\\u000a that could provide insights into pathogenic mechanisms common to these disorders.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  RNA microarray analyses (Agilent Human 1A(V2) 20K oligo arrays) were used to quantify gene expression in peripheral blood\\u000a cells from 20 monozygotic (MZ) twin pairs discordant for SAID. Six affected probands

Terrance P O’Hanlon; Lisa G Rider; Lu Gan; Rick Fannin; Richard S Paules; David M Umbach; Clarice R Weinberg; Ruchir R Shah; Deepak Mav; Mark F Gourley; Frederick W Miller

2011-01-01

192

NFAT5 regulates the canonical Wnt pathway and is required for cardiomyogenic differentiation  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer NFAT5 protein expression is downregulated during cardiomyogenesis. Black-Right-Pointing-Pointer Inhibition of NFAT5 function suppresses canonical Wnt signaling. Black-Right-Pointing-Pointer Inhibition of NFAT5 function attenuates mesodermal induction. Black-Right-Pointing-Pointer NFAT5 function is required for cardiomyogenesis. -- Abstract: While nuclear factor of activated T cells 5 (NFAT5), a transcription factor implicated in osmotic stress response, is suggested to be involved in other processes such as migration and proliferation, its role in cardiomyogenesis is largely unknown. Here, we examined the role of NFAT5 in cardiac differentiation of P19CL6 cells, and observed that it was abundantly expressed in undifferentiated P19CL6 cells, and its protein expression was significantly downregulated by enhanced proteasomal degradation during DMSO-induced cardiomyogenesis. Expression of a dominant negative mutant of NFAT5 markedly attenuated cardiomyogenesis, which was associated with the inhibition of mesodermal differentiation. TOPflash reporter assay revealed that the transcriptional activity of canonical Wnt signaling was activated prior to mesodermal differentiation, and this activation was markedly attenuated by NFAT5 inhibition. Pharmacological activation of canonical Wnt signaling by [2 Prime Z, 3 Prime E]-6-bromoindirubin-3 Prime -oxime (BIO) restored Brachyury expression in NFAT5DN-expressing cells. Inhibition of NFAT5 markedly attenuated Wnt3 and Wnt3a induction. Expression of Dkk1 and Cerberus1, which are secreted Wnt antagonists, was also inhibited by NFAT5 inhibition. Thus, endogenous NFAT5 regulates the coordinated expression of Wnt ligands and antagonists, which are essential for cardiomyogenesis through the canonical Wnt pathway. These results demonstrated a novel role of NFAT5 in cardiac differentiation of stem cells.

Adachi, Atsuo [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan)] [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan); Takahashi, Tomosaburo, E-mail: ttaka@koto.kpu-m.ac.jp [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan)] [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan); Ogata, Takehiro; Imoto-Tsubakimoto, Hiroko; Nakanishi, Naohiko [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan)] [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan); Ueyama, Tomomi, E-mail: toueyama-circ@umin.ac.jp [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan)] [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan); Matsubara, Hiroaki [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan)] [Department of Cardiovascular Medicine, Kyoto Prefectural University of Medicine, Kyoto 602-8566 (Japan)

2012-09-28

193

Immortalized Suprachiasmatic Nucleus Cells Express Components of Multiple Circadian Regulatory Pathways  

E-print Network

that differentiated SCN 2.2 cultures expressed a broad range of putative clock genes, as well as components of daytime suprachiasmatic nucleus (SCN). The SCN drives circadian behavior, expresses rhythmic gene expression pathways that characterize SCN function. Rhyth- mic gene expression has been demonstrated in NIH/ 3T3

Gillette, Martha U.

194

Functional replacement of a primary metabolic pathway via multiple independent eukaryote-to-eukaryote gene transfers  

E-print Network

recognized as a major force in the evolution of prokaryotes (e.g. Boucher et al., 2003). However transferred between prokaryotes as well as from prokaryotes to eukaryotes [e.g. the transfer of a pathway involved in vitamin B6 biosynthesis, from a prokaryotic source to a nematode; (Craig et al., 2008

Nedelcu, Aurora M.

195

Multiple phytohormone signalling pathways modulate susceptibility of tomato plants to Alternaria alternata f. sp. lycopersici.  

PubMed

Three phytohormone molecules - ethylene (ET), jasmonic acid (JA) and salicylic acid (SA) - play key roles in mediating disease response to necrotrophic fungal pathogens. This study investigated the roles of the ET, JA, and SA pathways as well as their crosstalk during the interaction between tomato (Solanum lycopersicum) plants and a necrotrophic fungal pathogen Alternaria alternata f. sp. lycopersici (AAL). Both the ET and JASMONIC ACID INSENSITIVE1 (JAI1) receptor-dependent JA signalling pathways are necessary for susceptibility, while SA response promotes resistance to AAL infection. In addition, the role of JA in susceptibility to AAL is partly dependent on ET biosynthesis and perception, while the SA pathway enhances resistance to AAL and antagonizes the ET response. Based on these results, it is proposed that ET, JA, and SA each on their own can influence the susceptibility of tomato to AAL. Furthermore, the functions of JA and SA in susceptibility to the pathogen are correlated with the enhanced or decreased action of ET, respectively. This study has revealed the functional relationship among the three key hormone pathways in tomato defence against AAL. PMID:23264518

Jia, Chengguo; Zhang, Liping; Liu, Lihong; Wang, Jiansheng; Li, Chuanyou; Wang, Qiaomei

2013-01-01

196

The aryl hydrocarbon receptor cross-talks with multiple signal transduction pathways  

PubMed Central

Exposure to toxic polycyclic aromatic hydrocarbons raises a number of toxic and carcinogenic responses in experimental animals and humans mediated for the most part by the aryl hydrocarbon---or dioxin---receptor (AHR). The AHR is a ligand-activated transcription factor whose central role in the induction of drug-metabolizing enzymes has long been recognized. For quite some time now, it has become clear that the AHR also functions in pathways outside of its role in detoxification and that perturbation of these pathways by xenobiotic ligands may be an important part of the toxicity of these compounds. AHR activation by some of its ligands participates among others in pathways critical to cell cycle regulation, mitogen-activated protein kinase cascades, immediate-early gene induction, cross-talk within the RB/E2F axis and mobilization of crucial calcium stores. Ultimately, the effect of a particular AHR ligand may depend as much on the adaptive interactions that it established with pathways and proteins expressed in a specific cell or tissue as on the toxic responses that it raises. PMID:18817753

Puga, Alvaro; Ma, Ci; Marlowe, Jennifer L.

2009-01-01

197

Multiple phytohormone signalling pathways modulate susceptibility of tomato plants to Alternaria alternata f. sp. lycopersici  

PubMed Central

Three phytohormone molecules – ethylene (ET), jasmonic acid (JA) and salicylic acid (SA) – play key roles in mediating disease response to necrotrophic fungal pathogens. This study investigated the roles of the ET, JA, and SA pathways as well as their crosstalk during the interaction between tomato (Solanum lycopersicum) plants and a necrotrophic fungal pathogen Alternaria alternata f. sp. lycopersici (AAL). Both the ET and JASMONIC ACID INSENSITIVE1 (JAI1) receptor-dependent JA signalling pathways are necessary for susceptibility, while SA response promotes resistance to AAL infection. In addition, the role of JA in susceptibility to AAL is partly dependent on ET biosynthesis and perception, while the SA pathway enhances resistance to AAL and antagonizes the ET response. Based on these results, it is proposed that ET, JA, and SA each on their own can influence the susceptibility of tomato to AAL. Furthermore, the functions of JA and SA in susceptibility to the pathogen are correlated with the enhanced or decreased action of ET, respectively. This study has revealed the functional relationship among the three key hormone pathways in tomato defence against AAL. PMID:23264518

Jia, Chengguo; Zhang, Liping; Wang, Qiaomei

2013-01-01

198

Multiple signalling pathways underlie the protective effect of levosimendan in cardiac myocytes.  

PubMed

Levosimendan is a cardiovascular drug for the treatment of acute and decompensated heart failure. The current weight of evidence on the cardioprotective effects of levosimendan originates from whole heart models and there is no information on the mechanism whereby signalling pathways are activated. In the present study, we investigated the effect of levosimendan on ischaemia/reperfusion injury and the underlying mechanism in cardiac myocytes. Pretreatment with levosimendan reversed the effects of ischaemia and ischaemia/reperfusion on cell viability and enhanced phosphorylation of Akt, p38-mitogen activated protein kinase (MAPK) and extracellular signal-regulated kinases 1/2 (ERK1/2). Inhibitors of these kinases and the blocker of the mitochondrial K(ATP) channels, 5-hydroxydecanoate, completely abolished the protection afforded by levosimendan. Levosimendan stimulated the phosphorylation of Akt, ERK1/2 and p38-MAPK with different kinetics and the activation of these pathways was dependent on the opening of the mitochondrial K(ATP) channels and the production of oxygen free radicals. The levosimendan-induced phosphorylation of ERK1/2 and Akt was reduced by inhibitors of epidermal growth factor receptor and Src. On the other hand, inhibition of the protein kinase A (PKA) pathway reduced phosphorylation of p38-MAPK. Furthermore, p38-MAPK was activated when a phosphodiesterase inhibitor or a selective PKA activator was used. Overall, our results suggest that levosimendan regulates the wiring of the natural salvaging pathways to execute the prosurvival signals. This network includes Akt, ERK1/2 and p38-MAPK. Opening of mitochondrial K(ATP) channels and the subsequent production of oxygen free radicals, the epidermal growth factor receptor/Src, and the cAMP/PKA pathways seem to mediate this response. PMID:21664904

Markou, Thomais; Makridou, Zoe; Galatou, Eleftheria; Lazou, Antigone

2011-09-30

199

The Requirement for Sodium as a Micronutrient by Species Having the C4 Dicarboxylic Photosynthetic Pathway  

PubMed Central

Six species having characteristics of plants with the C4 dicarboxylic photosynthetic pathway, Echinochloa utilis L. Ohwi et Yabuno (Japanese millet), Cynodon dactylon L. (Bermuda grass), Kyllinga brevifolia Rottb., Amaranthus tricolor L. cv. Early splendour, Kochia childsii Hort., and Portulaca grandiflora Hook (rose moss), responded decisively to 0.1 milliequivalent per liter NaCl supplied to their culture solutions initially containing less than 0.08 microequivalent per liter Na. Chlorosis and necrosis occurred in leaves of plants not receiving sodium. Portulaca failed to set flower in the sodium-deficient cultures. Under similar conditions Poa pratensis L. (Kentucky blue grass) having characteristics of the C3 photosynthetic pathway made normal growth and did not respond to the addition of sodium. It is concluded from these results and previously reported work that sodium is generally essential for species having the C4 pathway but not for species with the C3 pathway. Images PMID:16658050

Brownell, P. F.; Crossland, C. J.

1972-01-01

200

Modulation of multiple pathways involved in the maintenance of neuronal function during aging by fisetin  

Microsoft Academic Search

Multiple factors have been implicated in the age-related declines in brain function. Thus, it is unlikely that modulating\\u000a only a single factor will be effective at slowing this decline. A better approach is to identify small molecules that have\\u000a multiple biological activities relevant to the maintenance of brain function. Over the last few years, we have identified\\u000a an orally active,

Pamela Maher

2009-01-01

201

Effect of multiple mutations in tricarboxylic acid cycle and one-carbon metabolism pathways on Edwardsiella ictaluri pathogenesis.  

PubMed

Edwardsiella ictaluri is a Gram-negative facultative intracellular pathogen causing enteric septicemia of catfish (ESC). We have shown recently that tricarboxylic acid cycle (TCA) and one-carbon (C1) metabolism are involved in E. ictaluri pathogenesis. However, the effect of multiple mutations in these pathways is unknown. Here, we report four novel E. ictaluri mutants carrying double gene mutations in TCA cycle (Ei?mdh?sdhC, Ei?frdA?sdhC), C1 metabolism (Ei?glyA?gcvP), and both TCA and C1 metabolism pathways (Ei?gcvP?sdhC). In-frame gene deletions were constructed by allelic exchange and mutants' virulence and vaccine efficacy were evaluated using in vivo bioluminescence imaging (BLI) as well as end point mortality counts in catfish fingerlings. Results indicated that all the double gene mutants were attenuated compared to wild-type (wt) E. ictaluri. There was a 1.39-fold average reduction in bioluminescence, and hence bacterial numbers, from all the mutants except for Ei?frdA?sdhC at 144 h post-infection. Vaccination with mutants was very effective in protecting channel catfish against subsequent infection with virulent E. ictaluri 93-146 strain. In particular, immersion vaccination resulted in complete protection. Our results provide further evidence on the importance of TCA and C1 metabolism pathways in bacterial pathogenesis. PMID:24418045

Dahal, N; Abdelhamed, H; Lu, J; Karsi, A; Lawrence, M L

2014-02-21

202

Multiple signaling pathways regulate contractile activity?mediated PGC?1? gene expression and activity in skeletal muscle cells  

PubMed Central

Abstract PGC?1? is an important transcriptional coactivator that plays a key role in mediating mitochondrial biogenesis. Within seconds of the onset of contractile activity, a number of rapid cellular events occur that form part of the initial signaling processes involved in PGC?1? gene regulation, such as elevations in cytoplasmic calcium, AMPK and p38 activation, and elevated ROS production. We observed that basal levels of PGC?1? promoter activity were more sensitive to resting Ca2+ levels, compared to ROS, p38 or, AMPK signaling. Moreover, enhanced PGC?1? transcription and post?translational activity on DNA were a result of the activation of multiple signal transduction pathways during contractile activity of myotubes. AMPK, ROS, and Ca2+ appear to be necessary for the regulation of contractile activity?induced PGC?1? gene expression, governed partly through p38 MAPK and CaMKII activity. Whether these signaling pathways are arranged as a linear sequence of events, or as largely independent pathways during contractile activity, remains to be determined. PMID:24843073

Zhang, Yuan; Uguccioni, Giulia; Ljubicic, Vladimir; Irrcher, Isabella; Iqbal, Sobia; Singh, Kaustabh; Ding, Shuzhe; Hood, David A.

2014-01-01

203

Differential gene expression in multiple neurological, inflammatory and connective tissue pathways in a spontaneous model of human small vessel stroke  

PubMed Central

Aims Cerebral small vessel disease (SVD) causes a fifth of all strokes plus diffuse brain damage leading to cognitive decline, physical disabilities and dementia. The aetiology and pathogenesis of SVD are unknown, but largely attributed to hypertension or microatheroma. Methods We used the spontaneously hypertensive stroke-prone rat (SHRSP), the closest spontaneous experimental model of human SVD, and age-matched control rats kept under identical, non-salt-loaded conditions, to perform a blinded analysis of mRNA microarray, qRT-PCR and pathway analysis in two brain regions (frontal and mid-coronal) commonly affected by SVD in the SHRSP at age five, 16 and 21 weeks. Results We found gene expression abnormalities, with fold changes ranging from 2.5 to 59 for the 10 most differentially expressed genes, related to endothelial tight junctions (reduced), nitric oxide bioavailability (reduced), myelination (impaired), glial and microglial activity (increased), matrix proteins (impaired), vascular reactivity (impaired) and albumin (reduced), consistent with protein expression defects in the same rats. All were present at age 5 weeks thus predating blood pressure elevation. ‘Neurological’ and ‘inflammatory’ pathways were more affected than ‘vascular’ functional pathways. Conclusions This set of defects, although individually modest, when acting in combination could explain the SHRSP's susceptibility to microvascular and brain injury, compared with control rats. Similar combined, individually modest, but multiple neurovascular unit defects, could explain susceptibility to spontaneous human SVD. PMID:24417612

Bailey, Emma L; McBride, Martin W; Beattie, Wendy; McClure, John D; Graham, Delyth; Dominiczak, Anna F; Sudlow, Cathie LM; Smith, Colin; Wardlaw, Joanna M

2014-01-01

204

A MAP Kinase pathway in Caenorhabditis elegans is required for defense against infection by opportunistic Proteus species.  

PubMed

Caenorhabditis elegans innate immunity requires a conserved mitogen activated protein kinase (MAPK) pathway that regulates the basal and pathogen-induced expression of immune effectors. Being in the group of opportunistic pathogens, Proteus spp. cause large number of nosocomial infections. Since, Proteus spp. do not cause death in wild type C. elegans, to understand the role and contribution of MAP Kinase pathway, the mutants (sek-1 and pmk-1) of this pathway were employed. Physiological experiments revealed that the Proteus spp. were able to kill MAP Kinase pathway mutant's C. elegans significantly. To understand the involvement of innate immune pathways specific players at the mRNA level, the regulation of few candidate antimicrobial genes were kinetically investigated during Proteus spp. infections. Real-time PCR analysis indicated a regulation of few candidate immune regulatory genes (F08G5.6, lys-7, nlp-29, ATF-7 and daf-16) during the course of Proteus spp. infections. In addition, the lipopolysaccharides (LPS) isolated from Proteus mirabilis upon exposure to mutant C. elegans showed modifications at their functional regions suggesting that the pathogen modifies its internal machinery according to the specific host for effective pathogenesis. PMID:23597661

JebaMercy, Gnanasekaran; Vigneshwari, Loganathan; Balamurugan, Krishnaswamy

2013-01-01

205

Oyster Shell Proteins Originate from Multiple Organs and Their Probable Transport Pathway to the Shell Formation Front  

PubMed Central

Mollusk shell is one kind of potential biomaterial, but its vague mineralization mechanism hinders its further application. Mollusk shell matrix proteins are important functional components that are embedded in the shell, which play important roles in shell formation. The proteome of the oyster shell had been determined based on the oyster genome sequence by our group and gives the chance for further deep study in this area. The classical model of shell formation posits that the shell proteins are mantle-secreted. But, in this study, we further analyzed the shell proteome data in combination with organ transcriptome data and we found that the shell proteins may be produced by multiple organs though the mantle is still the most important organ for shell formation. To identify the transport pathways of these shell proteins not in classical model of shell formation, we conducted a shell damage experiment and we determined the shell-related gene set to identify the possible transport pathways from multiple organs to the shell formation front. We also found that there may exist a remodeling mechanism in the process of shell formation. Based on these results along with some published results, we proposed a new immature model, which will help us think about the mechanism of shell formation in a different way. PMID:23840499

Zhu, Yabing; Du, Yishuai; Song, Xiaorui; Chen, Yuanxin; Huang, Ronglian; Que, Huayong; Fang, Xiaodong; Zhang, Guofan

2013-01-01

206

Multispecific Drug Transporter Slc22a8 (Oat3) Regulates Multiple Metabolic and Signaling Pathways  

PubMed Central

Multispecific drug transporters of the solute carrier and ATP-binding cassette families are highly conserved through evolution, but their true physiologic role remains unclear. Analyses of the organic anion transporter 3 (OAT3; encoded by Slc22a8/Oat3, originally Roct) knockout mouse have confirmed its critical role in the renal handling of common drugs (e.g., antibiotics, antivirals, diuretics) and toxins. Previous targeted metabolomics of the knockout of the closely related Oat1 have demonstrated a central metabolic role, but the same approach with Oat3 failed to reveal a similar set of endogenous substrates. Nevertheless, the Oat3 knockout is the only Oat described so far with a physiologically significant phenotype, suggesting the disturbance of metabolic or signaling pathways. Here we analyzed global gene expression in Oat3 knockout tissue, which implicated OAT3 in phase I and phase II metabolism (drug metabolizing enzymes or DMEs), as well as signaling pathways. Metabolic reconstruction with the recently developed “mouse Recon1” supported the involvement of Oat3 in the aforementioned pathways. Untargeted metabolomics were used to determine whether the predicted metabolic alterations could be confirmed. Many significant changes were observed; several metabolites were tested for direct interaction with mOAT3, whereas others were supported by published data. Oat3 thus appears critical for the handling of phase I (hydroxylation) and phase II (glucuronidation) metabolites. Oat3 also plays a role in bioenergetic pathways (e.g., the tricarboxylic acid cycle), as well as those involving vitamins (e.g., folate), steroids, prostaglandins, gut microbiome products, uremic toxins, cyclic nucleotides, amino acids, glycans, and possibly hyaluronic acid. The data seemingly consistent with the Remote Sensing and Signaling Hypothesis (Ahn and Nigam, 2009; Wu et al., 2011), also suggests that Oat3 is essential for the handling of dietary flavonoids and antioxidants. PMID:23920220

Wu, Wei; Jamshidi, Neema; Eraly, Satish A.; Liu, Henry C.; Bush, Kevin T.; Palsson, Bernhard O.

2013-01-01

207

PEP-1-CAT protects hypoxia/reoxygenation-induced cardiomyocyte apoptosis through multiple sigaling pathways  

PubMed Central

Background Catalase (CAT) breaks down H2O2 into H2O and O2 to protects cells from oxidative damage. However, its translational potential is limited because exogenous CAT cannot enter living cells automatically. This study is aimed to investigate if PEP-1-CAT fusion protein can effectively protect cardiomyocytes from oxidative stress due to hypoxia/reoxygenation (H/R)-induced injury. Methods H9c2 cardomyocytes were pretreated with catalase (CAT) or PEP-1-CAT fusion protein followed by culturing in a hypoxia and re-oxygenation condition. Cell apoptosis were measured by Annexin V and PI double staining and Flow cytometry. Intracellular superoxide anion level was determined, and mitochondrial membrane potential was measured. Expression of apoptosis-related proteins including Bcl-2, Bax, Caspase-3, PARP, p38 and phospho-p38 was analyzed by western blotting. Results PEP-1-CAT protected H9c2 from H/R-induced morphological alteration and reduced the release of lactate dehydrogenase (LDH) and malondialdehyde content. Superoxide anion production was also decreased. In addition, PEP-1-CAT inhibited H9c2 apoptosis and blocked the expression of apoptosis stimulator Bax while increased the expression of Bcl-2, leading to an increased mitochondrial membrane potential. Mechanistically, PEP-1-CAT inhibited p38 MAPK while activating PI3K/Akt and Erk1/2 signaling pathways, resulting in blockade of Bcl2/Bax/mitochondrial apoptotic pathway. Conclusion Our study has revealed a novel mechanism by which PEP-1-CAT protects cardiomyocyte from H/R-induced injury. PEP-1-CAT blocks Bcl2/Bax/mitochondrial apoptotic pathway by inhibiting p38 MAPK while activating PI3K/Akt and Erk1/2 signaling pathways. PMID:23642335

2013-01-01

208

Multiple signaling pathways control nitrogen-mediated root elongation in maize  

PubMed Central

Response of root system architecture to nutrient availability is an essential way for plants to adapt to soil environments. Nitrogen can affect root development either as a result of changes in the external concentration, or through changes in the internal nutrient status of the plant. Low soil N stimulates root elongation in maize. Recent evidence suggests that plant hormones auxin and cytokinin, as well as NO signaling pathway, are involved in the regulation of root elongation by low nitrogen nutrition. PMID:19704443

Chen, Fanjun; Zhang, Fusuo

2008-01-01

209

Multiple signaling pathways control nitrogen-mediated root elongation in maize.  

PubMed

Response of root system architecture to nutrient availability is an essential way for plants to adapt to soil environments. Nitrogen can affect root development either as a result of changes in the external concentration, or through changes in the internal nutrient status of the plant. Low soil N stimulates root elongation in maize. Recent evidence suggests that plant hormones auxin and cytokinin, as well as NO signaling pathway, are involved in the regulation of root elongation by low nitrogen nutrition. PMID:19704443

Mi, Guohua; Chen, Fanjun; Zhang, Fusuo

2008-11-01

210

Noise-induced quantum coherence in photosynthetic complexes with multiple energy transfer pathways  

E-print Network

We theoretically investigate exciton relaxation dynamics in molecular aggregates based on model photosynthetic complexes under various conditions of incoherent excitation. We show that noise-induced quantum coherence is generated between spatially-separated exciton states which belong to the same or different energy transfer pathways, coupled via real and virtual transfer processes. Such quantum coherence effects may be used to improve light-harvesting efficiency and to reveal quantum phenomena in biology.

Dmitri V. Voronine; Konstantin E. Dorfman; Bin Cao; Amitabh Joshi

2014-08-12

211

The Glycolytic Inhibitor 2-Deoxyglucose Activates Multiple Prosurvival Pathways through IGF1R*  

PubMed Central

Recent molecular studies indicate that aerobic glycolysis plays an important role in tumorigenesis and is a valid target for cancer therapy. Although 2-deoxyglucose (2-DG) is well characterized as a glycolytic inhibitor, we recently discovered that it activates a prosurvival oncoprotein, AKT, through PI3K. In this study, we discovered that 2-DG treatments disrupted the binding between insulin-like growth factor 1 (IGF-1) and IGF-binding protein 3 (IGFBP3) so that the free form of IGF-1 could be released from the IGF-1·IGFBP3 complex to activate IGF-1 receptor (IGF1R) signaling. Because IGF1R signaling is involved, PI3K/AKT constitutes only one of the prosurvival pathways that are activated by 2-DG treatment; we validated that MEK-ERK signaling was also induced in an IGF1R-dependent manner in some cancer cell lines. Furthermore, our phospho-specific antibody microarray analysis indicated that 2-DG up-regulated the phosphorylation of 64 sites within various signaling pathways in H460 cells. Chemical inhibition of IGF1R reduced 57 of these up-regulations. These data suggest that 2-DG-induced activation of many survival pathways can be jointly attenuated through IGF1R inhibition. Our in vitro analysis demonstrated that treatment with a combination of subtoxic doses of 2-DG and the IGF1R inhibitor II reduced cancer cell proliferation 90% and promoted significant apoptosis. PMID:19574224

Zhong, Diansheng; Xiong, Li; Liu, Tongrui; Liu, Xiuju; Liu, Xiangguo; Chen, Jing; Sun, Shi-Yong; Khuri, Fadlo R.; Zong, Yaping; Zhou, Qinghua; Zhou, Wei

2009-01-01

212

Multiple propionyl coenzyme A-supplying pathways for production of the bioplastic poly(3-hydroxybutyrate-co-3-hydroxyvalerate) in Haloferax mediterranei.  

PubMed

Haloferax mediterranei is able to accumulate the bioplastic poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with more than 10 mol% 3-hydroxyvalerate (3HV) from unrelated carbon sources. However, the pathways that produce propionyl coenzyme A (propionyl-CoA), an important precursor of 3HV monomer, have not yet been determined. Bioinformatic analysis of H. mediterranei genome indicated that this strain uses multiple pathways for propionyl-CoA biosynthesis, including the citramalate/2-oxobutyrate pathway, the aspartate/2-oxobutyrate pathway, the methylmalonyl-CoA pathway, and a novel 3-hydroxypropionate pathway. Cofeeding of pathway intermediates and inactivating pathway-specific genes supported that these four pathways were indeed involved in the biosynthesis of 3HV monomer. The novel 3-hydroxypropionate pathway that couples CO2 assimilation with PHBV biosynthesis was further confirmed by analysis of (13)C positional enrichment in 3HV. Notably, (13)C metabolic flux analysis showed that the citramalate/2-oxobutyrate pathway (53.0% flux) and the 3-hydroxypropionate pathway (30.6% flux) were the two main generators of propionyl-CoA from glucose. In addition, genetic perturbation on the transcriptome of the ?phaEC mutant (deficient in PHBV accumulation) revealed that a considerable number of genes in the four propionyl-CoA synthetic pathways were significantly downregulated. We determined for the first time four propionyl-CoA-supplying pathways for PHBV production in haloarchaea, particularly including a new 3-hydroxypropionate pathway. These results would provide novel strategies for the production of PHBV with controllable 3HV molar fraction. PMID:23435886

Han, Jing; Hou, Jing; Zhang, Fan; Ai, Guomin; Li, Ming; Cai, Shuangfeng; Liu, Hailong; Wang, Lei; Wang, Zejian; Zhang, Siliang; Cai, Lei; Zhao, Dahe; Zhou, Jian; Xiang, Hua

2013-05-01

213

Methoxychlor affects multiple hormone signaling pathways in the largemouth bass (Micropterus salmoides) liver  

PubMed Central

Methoxychlor (MXC) is an organochlorine pesticide that has been shown to have estrogenic activity by activating estrogen receptors and inducing vitellogenin production in male fish. Previous studies report that exposure to MXC induces changes in mRNA abundance of reproductive genes in the liver and testes of largemouth bass (Micropterus salmoides). The objective of the present study was to better characterize the mode of action of MXC by measuring the global transcriptomic response in the male largemouth liver using an oligonucleotide microarray. Microarray analysis identified highly significant changes in the expression of 37 transcripts (p<0.001) (20 induced and 17 decreased) in the liver after MXC injection and a total of 900 expression changes (p<0.05) in transcripts with high homology to known genes. Largemouth bass estrogen receptor alpha (esr1) and androgen receptor (ar) were among the transcripts that were increased in the liver after MXC treatment. Functional enrichment analysis identified the molecular functions of steroid binding and androgen receptor activity as well as steroid hormone receptor activity as being significantly over-represented gene ontology terms. Pathway analysis identified c-fos signaling as being putatively affected through both estrogen and androgen signaling. This study provides evidence that MXC elicits transcriptional effects through the estrogen receptor as well as androgen receptor-mediated pathways in the liver. PMID:21276474

Martyniuk, Christopher J.; Spade, Daniel J.; Blum, Jason L.; Kroll, Kevin J.; Denslow, Nancy D.

2011-01-01

214

CytoSolve: A Scalable Computational Method for Dynamic Integration of Multiple Molecular Pathway Models  

PubMed Central

A grand challenge of computational systems biology is to create a molecular pathway model of the whole cell. Current approaches involve merging smaller molecular pathway models’ source codes to create a large monolithic model (computer program) that runs on a single computer. Such a larger model is difficult, if not impossible, to maintain given ongoing updates to the source codes of the smaller models. This paper describes a new system called CytoSolve that dynamically integrates computations of smaller models that can run in parallel across different machines without the need to merge the source codes of the individual models. This approach is demonstrated on the classic Epidermal Growth Factor Receptor (EGFR) model of Kholodenko. The EGFR model is split into four smaller models and each smaller model is distributed on a different machine. Results from four smaller models are dynamically integrated to generate identical results to the monolithic EGFR model running on a single machine. The overhead for parallel and dynamic computation is approximately twice that of a monolithic model running on a single machine. The CytoSolve approach provides a scalable method since smaller models may reside on any computer worldwide, where the source code of each model can be independently maintained and updated. PMID:21423324

Dewey, C. Forbes

2010-01-01

215

The Effect of Multiple Single Nucleotide Polymorphisms in the Folic Acid Pathway Genes on Homocysteine Metabolism  

PubMed Central

Objective. To investigate the joint effects of the single nucleotide polymorphisms (SNPs) of genes in the folic acid pathway on homocysteine (Hcy) metabolism. Methods. Four hundred women with normal pregnancies were enrolled in this study. SNPs were identified by MassARRAY. Serum folic acid and Hcy concentration were measured. Analysis of variance (ANOVA) and support vector machine (SVM) regressions were used to analyze the joint effects of SNPs on the Hcy level. Results. SNPs of MTHFR (rs1801133 and rs3733965) were significantly associated with maternal serum Hcy level. In the different genotypes of MTHFR (rs1801133), SNPs of RFC1 (rs1051266), TCN2 (rs9606756), BHMT (rs3733890), and CBS (rs234713 and rs2851391) were linked with the Hcy level adjusted for folic acid concentration. The integrated SNPs scores were significantly associated with the residual Hcy concentration (RHC) (r = 0.247). The Hcy level was significantly higher in the group with high SNP scores than that in other groups with SNP scores of less than 0.2 (P = 0.000). Moreover, this difference was even more significant in moderate and high levels of folic acid. Conclusion. SNPs of genes in the folic acid pathway possibly affect the Hcy metabolism in the presence of moderate and high levels of folic acid. PMID:24524080

Liang, Shuang; Zhou, Yuanpeng; Wang, Huijun; Qian, Yanyan; Ma, Duan; Tian, Weidong; Persaud-Sharma, Vishwani; Yu, Chen; Ren, Yunyun; Zhou, Shufeng; Li, Xiaotian

2014-01-01

216

Methoxychlor affects multiple hormone signaling pathways in the largemouth bass (Micropterus salmoides) liver.  

PubMed

Methoxychlor (MXC) is an organochlorine pesticide that has been shown to have estrogenic activity by activating estrogen receptors and inducing vitellogenin production in male fish. Previous studies report that exposure to MXC induces changes in mRNA abundance of reproductive genes in the liver and testes of largemouth bass (Micropterus salmoides). The objective of the present study was to better characterize the mode of action of MXC by measuring the global transcriptomic response in the male largemouth liver using an oligonucleotide microarray. Microarray analysis identified highly significant changes in the expression of 37 transcripts (p<0.001) (20 induced and 17 decreased) in the liver after MXC injection and a total of 900 expression changes (p<0.05) in transcripts with high homology to known genes. Largemouth bass estrogen receptor alpha (esr1) and androgen receptor (ar) were among the transcripts that were increased in the liver after MXC treatment. Functional enrichment analysis identified the molecular functions of steroid binding and androgen receptor activity as well as steroid hormone receptor activity as being significantly over-represented gene ontology terms. Pathway analysis identified c-fos signaling as being putatively affected through both estrogen and androgen signaling. This study provides evidence that MXC elicits transcriptional effects through the estrogen receptor as well as androgen receptor-mediated pathways in the liver. PMID:21276474

Martyniuk, Christopher J; Spade, Daniel J; Blum, Jason L; Kroll, Kevin J; Denslow, Nancy D

2011-02-01

217

Targeting angiogenesis from multiple pathways simultaneously: BIBF 1120, an investigational novel triple angiokinase inhibitor.  

PubMed

Angiogenesis is considered one of the major components of tumor progression and metastasis. Interfering with the formation and stabilization of tumor blood vessels could increase tumor response rates and may translate into improved clinical outcomes in cancer patients. The clinical efficacy demonstrated in phase III trials with bevacizumab, a monoclonal antibody that targets vascular endothelial growth factor ligand, suggests that targeting angiogenesis is a rational approach to cancer management. Agents that target additional proangiogenic intracellular signaling pathways also have the potential to contribute to our anticancer armamentarium. Novel targeted agents that have antiangiogenic properties have been developed in recent years such as sorafenib, sunitinib, vandetanib, and others. Many of them inhibit additional pathways beyond vascular endothelial growth factor signaling. One of these investigational targeted agents is a triple angiokinase inhibitor known as BIBF 1120. This compound targets not only vascular endothelial growth factor receptors, but also fibroblast growth factor receptors, and platelet-derived growth factor receptors. The preliminary clinical efficacy of BIBF 1120 is discussed in the context of the most relevant clinical data in several malignancies including non-small cell lung cancer. PMID:21350804

Santos, Edgardo S; Gomez, Jorge E; Raez, Luis E

2012-06-01

218

Multiple pathways are responsible for Anti-inflammatory and Cardiovascular activities of Hordeum vulgare L.  

PubMed

Background Hordeum vulgare L. (HV or barley) is used by traditional healers to treat various inflammatory and cardiovascular diseases, without the knowledge of pharmacologic rationale behind its actions. This study was designed to explore the potential scientific mechanism(s) that could explain the use of Hordeum vulgare in traditional medicine as a treatment for various inflammatory and cardiovascular diseases.MethodsA crude extract and its three fractions were prepared from HV and screened for the inhibition of platelet aggregation and various metabolites of cyclooxygenase (COX), lipoxygenase (LOX) pathways of arachidonic acid (AA) metabolism as well as for its effects on certain antioxidant enzymes. Platelet aggregation was monitored using turbidometric principle, AA metabolism through radioimmunoassay and antioxidant enzymes by commercial kits using spectrophotometer.ResultsResults show that HV exhibited activities against all human platelet agonists used except adenine diphosphate, and inhibited both COX and LOX pathways of AA metabolism. It also elevated the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx). However, these activities were distributed in various fractions of HV. Aqueous fraction was most potent in elevating SOD activity; chloroform fraction had concentrated compounds responsible for COX inhibition while n-hexane seems to possess compounds responsible for LOX inhibition as well as the only fraction enhancing the activity of GPx.ConclusionsThese results suggest the likely mechanisms responsible for observed anti-inflammatory and cardiovascular effects of HV in traditional medicine. PMID:25428431

Gul, Saima; Ahmed, Sagheer; Kifli, Nurolaini; Uddin, Qazi; Batool Tahir, Nafisa; Hussain, Abrar; Jaafar, Hawa; Moga, Marius; Zia-Ul-Haq, Muhammad

2014-11-26

219

egl-4 acts through a transforming growth factor-beta/SMAD pathway in Caenorhabditis elegans to regulate multiple neuronal circuits in response to sensory cues.  

PubMed Central

Sensory cues regulate several aspects of behavior and development in Caenorhabditis elegans, including entry into and exit from an alternative developmental stage called the dauer larva. Three parallel pathways, including a TGF-beta-like pathway, regulate dauer formation. The mechanisms by which the activities of these pathways are regulated by sensory signals are largely unknown. The gene egl-4 was initially identified based on its egg-laying defects. We show here that egl-4 has many pleiotropies, including defects in chemosensory behavior, body size, synaptic transmission, and dauer formation. Our results are consistent with a role for egl-4 in relaying sensory cues to multiple behavioral and developmental circuits in C. elegans. By epistasis analysis, we also place egl-4 in the TGF-beta-like branch and show that a SMAD gene functions downstream of egl-4 in multiple egl-4-regulated pathways, including chemosensation. PMID:10978280

Daniels, S A; Ailion, M; Thomas, J H; Sengupta, P

2000-01-01

220

Multiplication  

NSDL National Science Digital Library

How sharp are your multiplication skills? Give these great math games a try ! Play Asteroids blaster and test your multiplication skills. How fast can you solve the problem... play a round of Baseball multiplication and see! Multiplication is fun and delicious with Crazy Cones. Help Lemonade Larry determine the correct amount! Test your multiplication skills with Tic Tac Toe! ...

Ms.Roberts

2009-02-24

221

Life Stress, Genes, and Depression: Multiple Pathways Lead to Increased Risk and New Opportunities for Intervention  

NSDL National Science Digital Library

This STKE Review with 2 figures and 122 references concerns the interaction between stress, genetic factors, and vulnerability to depression. Evidence suggests that the combination of genetics, early life stress, and ongoing stress determine how an individual responds to stress and his vulnerability to psychiatric disorders, such as depression. It is likely that genetic factors and life stress contribute not only to alterations in various neurotransmitter systems, but also to the impairments of cellular plasticity and resilience that are observed in depression. Increased understanding of the specific cellular and neurochemical alterations that contribute to depression, and of the intracellular signaling pathways that underlie cellular plasticity and resilience, may lead to the identification of novel therapeutic targets and, therefore, to the development of novel antidepressant therapies.

Dennis S. Charney (National Institute of Mental Health;Mood and Anxiety Disorders Research Program REV); Husseini K. Manji (National Institute of Mental Health;Laboratory of Molecular Pathophysiology REV)

2004-03-23

222

Targeting multiple angiogenic pathways simultaneously: experience with nintedanib in non-small-cell lung cancer.  

PubMed

Angiogenesis plays a major role in the growth and progression of non-small-cell lung cancer (NSCLC), and there is increasing interest in the development of therapies that block this particular aspect of tumorigenesis. Bevacizumab was the first US FDA-approved inhibitor of angiogenesis after demonstrating improved progression-free survival and overall survival in combination with chemotherapy in treating NSCLC. However, the benefit of bevacizumab is only modest and transient as the tumors inevitably develop resistance to this particular treatment. Therefore, new therapies are being developed that attempt to inhibit angiogenesis through several different pathways. One promising new drug, nintedanib, is an oral triple angiokinase inhibitor that acts by blocking not only VEGFR, but also FGFR and PDGFR, which are involved in the development of resistance to bevacizumab. This article discusses the rationale for this approach and summarizes the clinical trial data on nintedanib, including the two most recent Phase III trials. PMID:24947258

Durm, Greg; Hanna, Nasser

2014-05-01

223

Multiple signaling pathways mediate ghrelin-induced proliferation of hippocampal neural stem cells.  

PubMed

Ghrelin, an endogenous ligand for the GH secretagogue receptor (GHS-R) receptor 1a (GHS-R1a), has been implicated in several physiologic processes involving the hippocampus. The aim of this study was to investigate the molecular mechanisms of ghrelin-stimulated neurogenesis using cultured adult rat hippocampal neural stem cells (NSCs). The expression of GHS-R1a was detected in hippocampal NSCs, as assessed by western blot analysis and immunocytochemistry. Ghrelin treatment increased the proliferation of cultured hippocampal NSCs assessed by BrdU incorporation. The exposure of cells to the receptor-specific antagonist d-Lys-3-GHRP-6 abolished the proliferative effect of ghrelin. By contrast, ghrelin showed no significant effect on cell differentiation. The expression of GHS-R1a was significantly increased by ghrelin treatment. The analysis of signaling pathways showed that ghrelin caused rapid activation of ERK1/2 and Akt, which were blocked by the GHS-R1a antagonist. In addition, ghrelin stimulated the phosphorylation of Akt downstream effectors, such as glycogen synthase kinase (GSK)-3?, mammalian target of rapamycin (mTOR), and p70(S6K). The activation of STAT3 was also caused by ghrelin treatment. Furthermore, pretreatment of cells with specific inhibitors of MEK/ERK1/2, phosphatidylinositol-3-kinase (PI3K)/Akt, mTOR, and Jak2/STAT3 attenuated ghrelin-induced cell proliferation. Taken together, our results support a role for ghrelin in adult hippocampal neurogenesis and suggest the involvement of the ERK1/2, PI3K/Akt, and STAT3 signaling pathways in the mediation of the actions of ghrelin on neurogenesis. Our data also suggest that PI3K/Akt-mediated inactivation of GSK-3? and activation of mTOR/p70(S6K) contribute to the proliferative effect of ghrelin. PMID:23608221

Chung, Hyunju; Li, Endan; Kim, Yumi; Kim, Sehee; Park, Seungjoon

2013-07-01

224

Induction of Protein Secretory Pathway Is Required for Systemic Acquired Resistance  

Microsoft Academic Search

In plants, systemic acquired resistance (SAR) is established as a result of NPR1-regulated expression of pathogenesis-related (PR) genes. Using gene expression profiling in Arabidopsis, we found that in addition to controlling the expression of PR genes, NPR1 also directly controls the expression of the protein secretory pathway genes. Up-regulation of these genes is essential for SAR, because mutations in some

Dong Wang; Natalie D. Weaver; Meenu Kesarwani; Xinnian Dong

2005-01-01

225

ATP Requirements and Small Interfering RNA Structure in the RNA Interference Pathway  

Microsoft Academic Search

We examined the role of ATP in the RNA interference (RNAi) pathway. Our data reveal two ATP-dependent steps and suggest that the RNAi reaction comprises at least four sequential steps: ATP-dependent processing of double-stranded RNA into small interfering RNAs (siRNAs), incorporation of siRNAs into an inactive ?360 kDa protein\\/RNA complex, ATP-dependent unwinding of the siRNA duplex to generate an active

Antti Nykänen; Benjamin Haley; Phillip D. Zamore

2001-01-01

226

A Functional Slow Recycling Pathway of Transferrin is Required for Growth of Chlamydia  

PubMed Central

An inhibitor of host cell lysophospholipid acyltransferase, an enzyme involved in lipid metabolism blocked growth of the obligate intracellular pathogen Chlamydia through its action on the transport of transferrin (Tf) via the slow pathway of recycling. A detailed characterization of this inhibition revealed that Tf accumulated in vesicles positive for Rab11, with a concomitant reduction in the level of Tf found within the transport intermediate Rab4/11 hybrid vesicles. The net result was the failure to be recycled to the plasma membrane. In chlamydiae-infected cells, the Tf-containing Rab11-positive vesicles were typically found intimately associated with the inclusion, and treatment with the inhibitor caused their accumulation, suggesting that the timely progression and completion of Tf recycling was necessary for proper chlamydial growth. Growth inhibition by the compound could be negated by the simple removal of the Tf-containing fraction of the serum, a further indication that accumulation of Tf around the chlamydial inclusion was deleterious to the pathogen. Thus, it appears that manipulating the slow recycling pathway can have biological consequences for Chlamydia and implies the need to regulate carefully the interaction of the inclusion with this host trafficking pathway. PMID:21607082

Ouellette, Scot P.; Carabeo, Rey A.

2010-01-01

227

Understanding Autoimmune Mechanisms in Multiple Sclerosis Using Gene Expression Microarrays: Treatment Effect and Cytokine-related Pathways  

PubMed Central

Multiple sclerosis (MS) is a central nervous system disease in which activated autoreactive T-cells invade the blood brain barrier and initiate an inflammatory response that leads to myelin destruction and axonal loss. The etiology of MS, as well as the mechanisms associated with its unexpected onset, the unpredictable clinical course spanning decades, and the different rates of progression leading to disability over time, remains an enigma. We have applied gene expression microarrays technology in peripheral blood mononuclear cells (PBMC) to better understand MS pathogenesis and better target treatment approaches. A signature of 535 genes were found to distinguish immunomodulatory treatment effects between 13 treated and 13 untreated MS patients. In addition, the expression pattern of 1109 gene transcripts that were previously reported to significantly differentiate between MS patients and healthy subjects were further analyzed to study the effect of cytokine-related pathways on disease pathogenesis. When relative gene expression for 26 MS patients was compared to 18 healthy controls, 30 genes related to various cytokine-associated pathways were identified. These genes belong to a variety of families such as interleukins, small inducible cytokine subfamily and tumor necrosis factor ligand and receptor. Further analysis disclosed seven cytokine-associated genes within the immunomodulatory treatment signature, and two cytokine-associated genes SCYA4 (small inducible cytokine A4) and FCAR (Fc fragment of IgA, CD89) that were common to both the MS gene expression signature and the immunomodulatory treatment gene expression signature. Our results indicate that cytokine-associated genes are involved in various pathogenic pathways in MS and also related to immunomodulatory treatment effects. PMID:15559377

Achiron, A.; Gurevich, M.; Magalashvili, D.; Kishner, I.; Dolev, M.; Mandel, M.

2004-01-01

228

Patrinia scabiosaefolia extract suppresses proliferation and promotes apoptosis by inhibiting the STAT3 pathway in human multiple myeloma cells.  

PubMed

Signal transducer and activator of transcription 3 (STAT3) plays an important role in tumor cell survival and proliferation and thus has become a major focus in the development of anti-cancer therapies. Patrinia scabiosaefolia has been used for the treatment of various types of cancer. However, the precise mechanism of the anti-cancer activity of Patrinia scabiosaefolia remains unclear. In this study, we evaluated the effect of the ethanol extract of Patrinia scabiosaefolia (EEPS) on proliferation and apoptosis in human multiple myeloma U266 cells that persistently express phosphorylated STAT3, and investigated the possible molecular mechanisms mediating its biological effects. We found that EEPS inhibited the phosphorylation of STAT3 in U266 cells. Consequently, the inhibitory effect of EEPS on STAT3 activation resulted in the suppression of cell proliferation and the induction of cell apoptosis. Moreover, EEPS treatment inhibited the expression of cyclin D1 (a promoter of cell proliferation) and Bcl-2 (an inhibitor of apoptosis), two important target genes of the STAT3 signaling pathway. Our findings for the first time demonstrate that Patrinia scabiosaefolia inhibits proliferation and promotes the apoptosis of cancer cells via inhibition of the STAT3 pathway, which may in part explain its anti-cancer activity. PMID:21468570

Peng, Jun; Chen, Youqin; Lin, Jiumao; Zhuang, Qunchuan; Xu, Wei; Hong, Zhenfeng; Sferra, Thomas J

2011-01-01

229

Overcoming inherent resistance to histone deacetylase inhibitors in multiple myeloma cells by targeting pathways integral to the actin cytoskeleton  

PubMed Central

Histone deacetylase inhibitors (HDACi) are novel chemotherapeutics undergoing evaluation in clinical trials for the potential treatment of patients with multiple myeloma (MM). Although HDACi have demonstrable synergy when combined with proteasome inhibitors (PIs), recent evidence indicates that combination of HDACi and PI is beneficial only in a subset of patients with advanced MM, clearly indicating that other rational combinations should be explored. In this context we hypothesized that understanding the molecular signature associated with inherent resistance to HDACi would provide a basis for the identification of therapeutic combinations with improved clinical efficacy. Using human myeloma cell lines (HMCL) categorized as sensitive, intermediate or resistant to HDACi, gene expression profiling (GEP) and gene ontology enrichment analyses were performed to determine if a genetic signature associated with inherent resistance to HDACi-resistance could be identified. Correlation of GEP to increasing or decreasing sensitivity to HDACi indicated a unique 35-gene signature that was significantly enriched for two pathways – regulation of actin cytoskeleton and protein processing in endoplasmic reticulum. When HMCL and primary MM samples were treated with a combination of HDACi and agents targeting the signaling pathways integral to the actin cytoskeleton, synergistic cell death was observed in all instances, thus providing a rationale for combining these agents with HDACi for the treatment of MM to overcome resistance. This report validates a molecular approach for the identification of HDACi partner drugs and provides an experimental framework for the identification of novel therapeutic combinations for anti-MM treatment. PMID:24651437

Mithraprabhu, S; Khong, T; Spencer, A

2014-01-01

230

Network-Based Multiple Sclerosis Pathway Analysis with GWAS Data from 15,000 Cases and 30,000 Controls  

PubMed Central

Multiple sclerosis (MS) is an inflammatory CNS disease with a substantial genetic component, originally mapped to only the human leukocyte antigen (HLA) region. In the last 5 years, a total of seven genome-wide association studies and one meta-analysis successfully identified 57 non-HLA susceptibility loci. Here, we merged nominal statistical evidence of association and physical evidence of interaction to conduct a protein-interaction-network-based pathway analysis (PINBPA) on two large genetic MS studies comprising a total of 15,317 cases and 29,529 controls. The distribution of nominally significant loci at the gene level matched the patterns of extended linkage disequilibrium in regions of interest. We found that products of genome-wide significantly associated genes are more likely to interact physically and belong to the same or related pathways. We next searched for subnetworks (modules) of genes (and their encoded proteins) enriched with nominally associated loci within each study and identified those modules in common between the two studies. We demonstrate that these modules are more likely to contain genes with bona fide susceptibility variants and, in addition, identify several high-confidence candidates (including BCL10, CD48, REL, TRAF3, and TEC). PINBPA is a powerful approach to gaining further insights into the biology of associated genes and to prioritizing candidates for subsequent genetic studies of complex traits. PMID:23731539

Baranzini, Sergio E.; Khankhanian, Pouya; Patsopoulos, Nikolaos A.; Li, Michael; Stankovich, Jim; Cotsapas, Chris; Søndergaard, Helle Bach; Ban, Maria; Barizzone, Nadia; Bergamaschi, Laura; Booth, David; Buck, Dorothea; Cavalla, Paola; Celius, Elisabeth G.; Comabella, Manuel; Comi, Giancarlo; Compston, Alastair; Cournu-Rebeix, Isabelle; D’alfonso, Sandra; Damotte, Vincent; Din, Lennox; Dubois, Bénédicte; Elovaara, Irina; Esposito, Federica; Fontaine, Bertrand; Franke, Andre; Goris, An; Gourraud, Pierre-Antoine; Graetz, Christiane; Guerini, Franca R.; Guillot-Noel, Léna; Hafler, David; Hakonarson, Hakon; Hall, Per; Hamsten, Anders; Harbo, Hanne F.; Hemmer, Bernhard; Hillert, Jan; Kemppinen, Anu; Kockum, Ingrid; Koivisto, Keijo; Larsson, Malin; Lathrop, Mark; Leone, Maurizio; Lill, Christina M.; Macciardi, Fabio; Martin, Roland; Martinelli, Vittorio; Martinelli-Boneschi, Filippo; McCauley, Jacob L.; Myhr, Kjell-Morten; Naldi, Paola; Olsson, Tomas; Oturai, Annette; Pericak-Vance, Margaret A.; Perla, Franco; Reunanen, Mauri; Saarela, Janna; Saker-Delye, Safa; Salvetti, Marco; Sellebjerg, Finn; Sørensen, Per Soelberg; Spurkland, Anne; Stewart, Graeme; Taylor, Bruce; Tienari, Pentti; Winkelmann, Juliane; Zipp, Frauke; Ivinson, Adrian J.; Haines, Jonathan L.; Sawcer, Stephen; DeJager, Philip; Hauser, Stephen L.; Oksenberg, Jorge R.

2013-01-01

231

Yeast Pescadillo is required for multiple activities during 60S ribosomal subunit synthesis.  

PubMed Central

The Pescadillo protein was identified via a developmental defect and implicated in cell cycle progression. Here we report that human Pescadillo and its yeast homolog (Yph1p or Nop7p) are localized to the nucleolus. Depletion of Nop7p leads to nuclear accumulation of pre-60S particles, indicating a defect in subunit export, and it interacts genetically with a tagged form of the ribosomal protein Rpl25p, consistent with a role in subunit assembly. Two pre-rRNA processing pathways generate alternative forms of the 5.8S rRNA, designated 5.8S(L) and 5.8Ss. In cells depleted for Nop7p, the 27SA3 pre-rRNA accumulated, whereas later processing intermediates and the mature 5.8Ss rRNA were depleted. Less depletion was seen for the 5.8S(L) pathway. TAP-tagged Nop7p coprecipitated precursors to both 5.8S(L) and 5.8Ss but not the mature rRNAs. We conclude that Nop7p is required for efficient exonucleolytic processing of the 27SA3 pre-rRNA and has additional functions in 60S subunit assembly and transport. Nop7p is a component of at least three different pre-60S particles, and we propose that it carries out distinct functions in each of these complexes. PMID:12022229

Oeffinger, Marlene; Leung, Anthony; Lamond, Angus; Tollervey, David; Lueng, Anthony

2002-01-01

232

Multiple Smaller Missions as a Direct Pathway to Mars Sample Return  

NASA Technical Reports Server (NTRS)

Recent discoveries by the Mars Exploration Rovers, Mars Express, Mars Odyssey, and Mars Reconnaissance Orbiter spacecraft include multiple, tantalizing astrobiological targets representing both past and present environments on Mars. The most desirable path to Mars Sample Return (MSR) would be to collect and return samples from that site which provides the clearest examples of the variety of rock types considered a high priority for sample return (pristine igneous, sedimentary, and hydrothermal). Here we propose an MSR architecture in which the next steps (potentially launched in 2018) would entail a series of smaller missions, including caching, to multiple landing sites to verify the presence of high priority sample return targets through in situ analyses. This alternative architecture to one flagship-class sample caching mission to a single site would preserve a direct path to MSR as stipulated by the Planetary Decadal Survey, while permitting investigation of diverse deposit types and providing comparison of the site of returned samples to other aqueous environments on early Mars

Niles, P. B.; Draper, D. S.; Evans, C. A.; Gibson, E. K.; Graham, L. D.; Jones, J. H.; Lederer, S. M.; Ming, D.; Seaman, C. H.; Archer, P. D.; Andrews-Hanna, J.; Baldridge, A. M.; Bourke, M. C.; Crown, D. A.; Fries, M.; Knudson, A. T.; Michalski, J.; Dobrea, E. Noe; Vaniman, D.; Weitz, C. M.; Williams, R. M. E.; Bell, J. F., III; Knauth, L. P.

2012-01-01

233

Proper actin ring formation and septum constriction requires coordinated regulation of SIN and MOR pathways through the germinal centre kinase MST-1.  

PubMed

Nuclear DBF2p-related (NDR) kinases constitute a functionally conserved protein family of eukaryotic regulators that control cell division and polarity. In fungi, they function as effector kinases of the morphogenesis (MOR) and septation initiation (SIN) networks and are activated by pathway-specific germinal centre (GC) kinases. We characterized a third GC kinase, MST-1, that connects both kinase cascades. Genetic and biochemical interactions with SIN components and life cell imaging identify MST-1 as SIN-associated kinase that functions in parallel with the GC kinase SID-1 to activate the SIN-effector kinase DBF-2. SID-1 and MST-1 are both regulated by the upstream SIN kinase CDC-7, yet in an opposite manner. Aberrant cortical actomyosin rings are formed in ?mst-1, which resulted in mis-positioned septa and irregular spirals, indicating that MST-1-dependent regulation of the SIN is required for proper formation and constriction of the septal actomyosin ring. However, MST-1 also interacts with several components of the MOR network and modulates MOR activity at multiple levels. MST-1 functions as promiscuous enzyme and also activates the MOR effector kinase COT-1 through hydrophobic motif phosphorylation. In addition, MST-1 physically interacts with the MOR kinase POD-6, and dimerization of both proteins inactivates the GC kinase hetero-complex. These data specify an antagonistic relationship between the SIN and MOR during septum formation in the filamentous ascomycete model Neurospora crassa that is, at least in part, coordinated through the GC kinase MST-1. The similarity of the SIN and MOR pathways to the animal Hippo and Ndr pathways, respectively, suggests that intensive cross-communication between distinct NDR kinase modules may also be relevant for the homologous NDR kinases of higher eukaryotes. PMID:24762679

Heilig, Yvonne; Dettmann, Anne; Mouriño-Pérez, Rosa R; Schmitt, Kerstin; Valerius, Oliver; Seiler, Stephan

2014-04-01

234

Multiple Requirements of the Focal Dermal Hypoplasia Gene Porcupine during Ocular Morphogenesis.  

PubMed

Wnt glycoproteins control key processes during development and disease by activating various downstream pathways. Wnt secretion requires post-translational modification mediated by the O-acyltransferase encoded by the Drosophila porcupine homolog gene (PORCN). In humans, PORCN mutations cause focal dermal hypoplasia (FDH, or Goltz syndrome), an X-linked dominant multisystem birth defect that is frequently accompanied by ocular abnormalities such as coloboma, microphthalmia, or even anophthalmia. Although genetic ablation of Porcn in mouse has provided insight into the etiology of defects caused by ectomesodermal dysplasia in FDH, the requirement for Porcn and the actual Wnt ligands during eye development have been unknown. In this study, Porcn hemizygosity occasionally caused ocular defects reminiscent of FDH. Conditional inactivation of Porcn in periocular mesenchyme led to defects in mid- and hindbrain and in craniofacial development, but was insufficient to cause ocular abnormalities. However, a combination of conditional Porcn depletion in optic vesicle neuroectoderm, lens, and neural crest-derived periocular mesenchyme induced severe eye abnormalities with high penetrance. In particular, we observed coloboma, transdifferentiation of the dorsal and ventral retinal pigment epithelium, defective optic cup periphery, and closure defects of the eyelid, as well as defective corneal morphogenesis. Thus, Porcn is required in both extraocular and neuroectodermal tissues to regulate distinct Wnt-dependent processes during morphogenesis of the posterior and anterior segments of the eye. PMID:25451153

Bankhead, Elizabeth J; Colasanto, Mary P; Dyorich, Kayla M; Jamrich, Milan; Murtaugh, L Charles; Fuhrmann, Sabine

2015-01-01

235

Evidence for multiple pathways of sup 125 I-insulin internalization in isolated rat hepatocytes  

SciTech Connect

Insulin internalization has been characterized frequently as occurring by the coated pit pathway of receptor-mediated endocytosis. The present study in rat hepatocytes demonstrates that insulin internalization is, in part, receptor-mediated, but also occurs by nonreceptor-mediated or fluid-phase endocytosis. Endocytosis was probed with four perturbations: depletion of metabolic energy with anoxia, inhibition of endocytosis with phenylarsine oxide, disruption of coated pits with hyperosmolar sucrose, and inhibition of receptor recycling or ligand-receptor dissociation with monensin. Internalization of {sup 125}I-epidermal growth factor and {sup 125}I-asialofetuin was compared to {sup 125}I-insulin internalization. Pretreatment of cells with anoxia or hyperosmolarity inhibited {sup 125}I-insulin internalization by 40%; pretreatment with phenylarsine oxide resulted in inhibition by 54%. Monensin has no effect on uptake or degradation of a high insulin concentration, but inhibited degradation of a low insulin concentration resulting in intracellular accumulation of insulin. In contract, all four perturbations inhibited {sup 125}I-asialofetuin internalization by greater than 90%. Phenylarsine oxide almost completely abolished {sup 125}I-epidermal growth factor uptake; the other perturbations caused partial inhibition. Competition studies demonstrated that insulin internalization was receptor-mediated over a wide concentration range.

Moss, A.L.

1988-01-01

236

Multiple calcium pathways induce the expression of SNAP-25 protein in chromaffin cells.  

PubMed

Incubation of bovine adrenal chromaffin cells in high K+ (38 mM) during 24-48 h enhanced 2.5 to five times the expression of SNAP-25 protein and mRNA, respectively. This increase was reduced 86% by furnidipine (an L-type Ca2+ channel blocker) but was unaffected by either omega-conotoxin GVIA (an N-type Ca2+ channel blocker) or -agatoxin IVA (a P/Q-type Ca2+ channel blocker). Combined blockade of N and P/Q channels with omega-conotoxin MVIIC did, however, block by 76% the protein expression. The inhibitory effects of fumidipine were partially reversed when the external Ca2+ concentration was raised from 1.6 to 5 mM. These findings, together with the fact that nicotinic receptor activation or Ca2+ release from internal stores also enhanced SNAP-25 protein expression, suggest that an increment of cytosolic Ca2+ concentration ([Ca2+]), rather than its source or Ca2+ entry pathway, is the critical signal to induce the protein expression. The greater coupling between L-type Ca2+ channels and protein expression might be due to two facts: (a) L channels contributed 50% to the global [Ca2+]i rise induced by 38 mM K+ in indo-1-loaded chromaffin cells and (b) L channels undergo less inactivation than N or P/Q channels on sustained stimulation of these cells. PMID:10693936

García-Palomero, E; Montiel, C; Herrero, C J; García, A G; Alvarez, R M; Arnalich, F M; Renart, J; Lara, H; Cárdenas, A M

2000-03-01

237

Multiple charge-separation pathways in photosystem II: modeling of transient absorption kinetics.  

PubMed

We explain the transient absorption kinetics (E. Romero, I. H. M. van Stokkum, V. I. Novoderezhkin, J. P. Dekker, R. van Grondelle, Biochemistry 2010, 49, 4300) measured for isolated reaction centers of photosystem II at 77 K upon excitation of the primary donor band (680 nm). The excited-state dynamics is modeled on the basis of the exciton states of 6 cofactors coupled to 4 charge-transfer (CT) states. One CT state (corresponding to charge separation within the special pair) is supposed to be strongly coupled with the excited states, whereas the other radical pairs are supposed to be localized. Relaxation within the strongly coupled manifold and transfer to localized CT's are described by the modified Redfield and generalized Förster theories, respectively. A simultaneous and quantitative fit of the 680, 545, and 460 nm kinetics (corresponding to respectively the Q(y) transitions of the red-most cofactors, Q(x) transition of pheophytin, and pheophytin anion absorption) enables us to define the pathways and time scales of primary electron transfer. A consistent modeling of the data is only possible with a Scheme where charge separation occurs from both the accessory chlorophyll and from the special pair, giving rise to fast and slow components of the pheophytin anion formation, respectively. PMID:21322104

Novoderezhkin, Vladimir I; Romero, Elisabet; Dekker, Jan P; van Grondelle, Rienk

2011-02-25

238

Chemical modification and degradation of atrazine in Medicago sativa through multiple pathways.  

PubMed

Atrazine is a member of the triazine herbicide family intensively used to control weeds for crop production. In this study, atrazine residues and its degraded products in alfalfa (Medicago sativa) were characterized using UPLC-TOF-MS/MS. Most of atrazine absorbed in plants was found as chemically modified derivatives like deisopropylated atrazine (DIA), dehydrogenated atrazine (DHA), or methylated atrazine (MEA), and some atrazine derivatives were conjugated through different functional groups such as sugar, glutathione, and amino acids. Interestingly, the specific conjugates DHA+hGSH (homoglutathione) and MEA-HCl+hGSH in alfalfa were detected. These results suggest that atrazine in alfalfa can be degraded through different pathways. The increased activities of glycosyltransferase and glutathione S-transferase were determined to support the atrazine degradation models. The outcome of the work uncovered the detailed mechanism for the residual atrazine accumulation and degradation in alfalfa and will help to evaluate whether the crop is suitable to be cultivated in the atrazine-polluted soil. PMID:25226578

Zhang, Jing Jing; Lu, Yi Chen; Yang, Hong

2014-10-01

239

Pseudomonas aeruginosa fimL regulates multiple virulence functions by intersecting with Vfr-modulated pathways  

Microsoft Academic Search

Summary Virulence of Pseudomonas aeruginosa involves the co-ordinate expression of a range of factors including type IV pili (tfp), the type III secretion system (TTSS) and quorum sensing. Tfp are required for twitching motility, efficient biofilm formation, and for adhesion and type III secretion (TTS)-mediated damage to mam- malian cells. We describe a novel gene ( fimL ) that is

Cynthia B. Whitchurch; Scott A. Beatson; James C. Comolli; Thania Jakobsen; Jennifer L. Sargent; Jacob J. Bertrand; Joyce West; Mikkel Klausen; Leslie L. Waite; Pil Jung Kang; Tim Tolker-Nielsen; John S. Mattick; Joanne N. Engel

240

Replication of murine coronavirus requires multiple cysteines in the endodomain of spike protein  

SciTech Connect

A conserved cysteine-rich motif located between the transmembrane domain and the endodomain is essential for membrane fusion and assembly of coronavirus spike (S) protein. Here, we proved that three cysteines within the motif, but not dependent on position, are minimally required for the survival of the recombinant mouse hepatitis virus. When the carboxy termini with these mutated motifs of S proteins were respectively introduced into a heterogeneous protein, both incorporation into lipid rafts and S-palmitoylation of these recombinant proteins showed a similar quantity requirement to cysteine residues. Meanwhile, the redistribution of these proteins on cellular surface indicated that the absence of the positively charged rather than cysteine residues in the motif might lead the dramatic reduction in syncytial formation of some mutants with the deleted motifs. These results suggest that multiple cysteine as well as charged residues concurrently improves the membrane-associated functions of S protein in viral replication and cytopathogenesis.

Yang, Jinhua; Lv, Jun; Wang, Yuyan; Gao, Shuang; Yao, Qianqian; Qu, Di; Ye, Rong, E-mail: yerong24@fudan.edu.cn

2012-06-05

241

Concurrent activation of multiple vasoactive signaling pathways in vasoconstriction caused by tubuloglomerular feedback: a quantitative assessment.  

PubMed

Tubuloglomerular feedback (TGF) describes the negative relationship between (a) NaCl concentration at the macula densa and (b) glomerular filtration rate or glomerular capillary pressure. TGF-induced vasoconstriction of the afferent arteriole results from the enhanced effect of several vasoconstrictors with an effect size sequence of adenosine = 20-HETE > angiotensin II > thromboxane = superoxide > renal nerves > ATP. TGF-mediated vasoconstriction is limited by the simultaneous release of several vasodilators with an effect size sequence of nitric oxide > carbon monoxide = kinins > adenosine. The sum of the constrictor effects exceeds that of the dilator effects by the magnitude of the TGF response. The validity of the additive model used in this analysis can be tested by determining the effect of combined inhibition of some or all agents contributing to TGF. Multiple independent contributors to TGF are consistent with the variability of TGF and of the factors contributing to TGF resetting. PMID:25668021

Schnermann, Jurgen

2015-02-10

242

Simulating multiple merger pathways to the central kinematics of early-type galaxies  

NASA Astrophysics Data System (ADS)

Two-dimensional integral field surveys such as ATLAS3D are producing rich observational data sets yielding insights into galaxy formation. These new kinematic observations have highlighted the need to understand the evolutionary mechanisms leading to a spectrum of fast rotators and slow rotators in early-type galaxies. We address the formation of slow and fast rotators through a series of controlled, comprehensive hydrodynamical simulations, sampling idealized galaxy merger scenarios constructed from model spiral galaxies. Idealized and controlled simulations of this sort complement the more `realistic' cosmological simulations by isolating and analysing the effects of specific parameters, as we do in this paper. We recreate minor and major binary mergers, binary merger trees with multiple progenitors, and multiple sequential mergers. Within each of these categories of formation history, we correlate progenitor gas fraction, mass ratio, orbital pericentre, orbital ellipticity, and spin with remnant kinematic properties. We create kinematic profiles of these 95 simulations comparable to ATLAS3D data. By constructing remnant profiles of the projected specific angular momentum (? _R= < R|V|rangle / < R ?{V^2+? ^2}rangle), triaxiality, and measuring the incidences of kinematic twists and kinematically decoupled cores, we distinguish between varying formation scenarios. We find that binary mergers nearly always form fast rotators. Slow rotators can be formed from zero initial angular momentum configurations and gas-poor mergers, but are not as round as the ATLAS3D galaxies. Remnants of binary merger trees are triaxial slow rotators. Sequential mergers form round slow rotators that most resemble the ATLAS3D rotators.

Moody, Christopher E.; Romanowsky, Aaron J.; Cox, Thomas J.; Novak, G. S.; Primack, Joel R.

2014-10-01

243

Multiple pathways for the primary step of the spiropyran photochromic reaction: a CASPT2//CASSCF study.  

PubMed

CASSCF and CASPT2 studies on the reaction mechanism of the photochromic ring-opening process of a spiropyran (SP) (1',3',3'-trimethylspiro-[2H-1-benzopyran-2,2'-indoline], also known as BIPS) have been performed and possible excited-state C-O (and C-N) bond cleavage pathways and S1-to-S0 nonadiabatic transition channels have been explored. (1) The C-O bond dissociation in SP does not follow a conical-intersection mechanism that has been proposed in a model study with a simplified benzopyran. The CASSCF-optimized crossing points are actually avoided crossings with a large S1-S0 energy gap at the CASPT2 level; thus, they could not act as efficient S1-to-S0 funnels. (2) C-O bond cleavage paths on S1 leading to both the CCC (cis-cis-cis with respect to the configuration around ?, ?, ?) and TCC (trans-cis-cis) intermediates of merocyanine (MC) are barrierless, in line with the experimentally observed ultrafast formation of MC. (3) An unexpected low-energy hydrogen-out-of-plane (HOOP) valley on the (???*) surface was located not far from the C-O bond cleavage path and was suggested to be an efficient S1-to-S0 nonadiabatic decay channel. Triggered by the active HOOP mode, the molecule can easily access the S1-HOOP valley and then make a transition to the S0 surface through the narrow S1-S0 gap that exists in an extended region. Nonadiabatic decay through a conical intersection on C-N dissociation path as well as the HOOP funnel is responsible for high internal conversion yields of SP. These findings shedding light on the complex mechanism of SP-MC interconversion provide fundamental information for design spiropyran-based photochromic devices. PMID:23819704

Liu, Fengyi; Morokuma, Keiji

2013-07-24

244

Diosgenin inhibits superoxide generation in FMLP-activated mouse neutrophils via multiple pathways.  

PubMed

Diosgenin possesses anti-inflammatory and anticancer properties. Activated neutrophils produce high concentrations of the superoxide anion which is involved in the pathophysiology of inflammation-related diseases and cancer. In the present study, the inhibitory effect and possible mechanisms of diosgenin on superoxide generation were investigated in mouse bone marrow neutrophils. Diosgenin potently and concentration-dependently inhibited the extracellular and intracellular superoxide anion generation in Formyl-Met-Leu-Phe (FMLP)- activated neutrophils, with IC50 values of 0.50 ± 0.08 ?M and 0.66 ± 0.13 ?M, respectively. Such inhibition was not mediated by scavenging the superoxide anion or by a cytotoxic effect. Diosgenin inhibited the phosphorylation of p47phox and membrane translocation of p47phox and p67phox, and thus blocking the assembly of nicotinamide adenine dinucleotide phosphate oxidase. Moreover, cellular cyclic adenosine monophosphate (cAMP) levels and protein kinase A (PKA) expression were also effectively increased by diosgenin. It attenuated FMLP-induced increase of phosphorylation of cytosolic phospholipase A (cPLA2), p21-activated kinase (PAK), Akt, p38 mitogen-activated protein kinase (p38MAPK), extracellular signal-regulated kinase (ERK1/2), and c-Jun N-terminal kinase (JNK). Our data indicate that diosgenin exhibits inhibitory effects on superoxide anion production through the blockade of cAMP, PKA, cPLA2, PAK, Akt and MAPKs signaling pathways. The results may explain the clinical implications of diosgenin in the treatment of inflammation-related disorders. PMID:25246240

Lin, Y; Jia, R; Liu, Y; Gao, Y; Zeng, X; Kou, J; Yu, B

2014-12-01

245

Nociceptin inhibits uterine contractions in term-pregnant rats by signaling through multiple pathways.  

PubMed

The actions of the endogenous peptide nociceptin (PNOC; previously abbreviated as N/OFQ) on the myometrium have not been investigated previously. Our aim was to study the presence and functional role of PNOC in the modulation of uterine contractility in pregnant rats at term. The presence of PNOC and its receptors (OPRL1; previously called NOP) in the uterus were detected by radioimmunoassay and radioligand-binding experiments. The PNOC-stimulated G protein activation was assessed by a [(35)S]GTPgammaS-binding technique. The effects of PNOC in uterine rings precontracted with KCl or oxytocin were also tested in vitro. Uterine levels of cAMP were measured by enzyme immunoassay. The K(+) channel blockers tetraethylammonium and paxilline were used to study the role of K(+) channels in mediating the uterine effects of PNOC. Both PNOC and OPRL1 were present in the uterus. PNOC revealed a maximum contraction inhibition of approximately 30%, which was increased to 40% by naloxone. Naloxone and pertussis toxin significantly attenuated the G protein-stimulating effect of PNOC. The uterine cAMP levels were elevated by PNOC and naloxone and after preincubation with pertussis toxin. Tetraethylammonium and paxilline reduced the contraction-inhibiting effect of PNOC and naloxone to approximately 10% and 15%, respectively. We presume that PNOC plays a role in regulating uterine contractility at term. Its effect is mediated partly by stimulatory heterotrimeric G (G(s)) proteins coupled to OPRL1 receptors and elevated cAMP levels, and also by Ca(2+)-dependent K(+) channels. Our results demonstrate a novel action and signaling pathway for PNOC that might be a potential drug target. PMID:20237332

Klukovits, A; Tekes, K; Gündüz Cinar, O; Benyhe, S; Borsodi, A; Deák, B H; Hajagos-Tóth, J; Verli, J; Falkay, G; Gáspár, R

2010-07-01

246

The Hedgehog processing pathway is required for NSCLC growth and survival  

PubMed Central

Considerable interest has been generated from the results of recent clinical trials using SMOOTHENED (SMO) antagonists to inhibit the growth of HEDGEHOG (HH) signaling dependent tumors. This interest is tempered by the discovery of SMO mutations mediating resistance, underscoring the rationale for developing therapeutic strategies that interrupt HH signaling at levels distinct from those inhibiting SMO function. Here, we demonstrate that HH dependent non-small cell lung carcinoma (NSCLC) growth is sensitive to blockade of the HH pathway upstream of SMO, at the level of HH ligand processing. Individually, the use of different lentivirally delivered shRNA constructs targeting two functionally distinct HH-processing proteins, SKINNY HEDGEHOG (SKN) or DISPATCHED-1 (DISP-1), in NSCLC cell lines produced similar decreases in cell proliferation and increased cell death. Further, providing either an exogenous source of processed HH or a SMO agonist reverses these effects. The attenuation of HH processing, by knocking down either of these gene products, also abrogated tumor growth in mouse xenografts. Finally, we extended these findings to primary clinical specimens, showing that SKN is frequently over-expressed in NSCLC and that higher DISP-1 expression is associated with an unfavorable clinical outcome. Our results show a critical role for HH processing in HH-dependent tumors, identifies two potential druggable targets in the HH pathway, and suggest that similar therapeutic strategies could be explored to treat patients harboring HH ligand dependent cancers. PMID:22733134

Rodriguez-Blanco, Jezabel; Schilling, Neal S.; Tokhunts, Robert; Giambelli, Camilla; Long, Jun; Liang Fei, Dennis; Singh, Samer; Black, Kendall E.; Wang, Zhiqiang; Galimberti, Fabrizio; Bejarano, Pablo A.; Elliot, Sharon; Glassberg, Marilyn K.; Nguyen, Dao M.; Lockwood, William W.; Lam, Wan L.; Dmitrovsky, Ethan; Capobianco, Anthony J.; Robbins, David J.

2013-01-01

247

Modelling the Response of FOXO Transcription Factors to Multiple Post-Translational Modifications Made by Ageing-Related Signalling Pathways  

PubMed Central

FOXO transcription factors are an important, conserved family of regulators of cellular processes including metabolism, cell-cycle progression, apoptosis and stress resistance. They are required for the efficacy of several of the genetic interventions that modulate lifespan. FOXO activity is regulated by multiple post-translational modifications (PTMs) that affect its subcellular localization, half-life, DNA binding and transcriptional activity. Here, we show how a mathematical modelling approach can be used to simulate the effects, singly and in combination, of these PTMs. Our model is implemented using the Systems Biology Markup Language (SBML), generated by an ancillary program and simulated in a stochastic framework. The use of the ancillary program to generate the SBML is necessary because the possibility that many regulatory PTMs may be added, each independently of the others, means that a large number of chemically distinct forms of the FOXO molecule must be taken into account, and the program is used to generate them. Although the model does not yet include detailed representations of events upstream and downstream of FOXO, we show how it can qualitatively, and in some cases quantitatively, reproduce the known effects of certain treatments that induce various single and multiple PTMs, and allows for a complex spatiotemporal interplay of effects due to the activation of multiple PTM-inducing treatments. Thus, it provides an important framework to integrate current knowledge about the behaviour of FOXO. The approach should be generally applicable to other proteins experiencing multiple regulations. PMID:20567500

Smith, Graham R.; Shanley, Daryl P.

2010-01-01

248

Maximal adamantyl-substituted retinoid-related molecule-induced apoptosis requires NF-?B noncanonical and canonical pathway activation  

Microsoft Academic Search

NF-?B transcription factors have a critical role in regulating cell survival and apoptosis. We have previously shown that 4-(3-Cl-(1-adamantyl)-4-hydroxyphenyl)-3-chlorocinnamic acid (3-Cl-AHPC), an adamantyl-substituted retinoid molecule, induced apoptosis and required NF-?B activation in prostate and breast carcinoma cells. Here, we show that 3-Cl-AHPC activated both I?B kinase (IKK)? and IKK? with subsequent activation of the canonical and noncanonical NF-?B pathways in

L Farhana; M I Dawson; F Murshed; J A Fontana

2011-01-01

249

Targeting NGF pathway for developing neuroprotective therapies for multiple sclerosis and other neurological diseases.  

PubMed

Inflammation is the first line of defense against injury and infection and works both by controlling the ongoing pathological processes and by promoting neuroprotection and regeneration. When the inflammatory response is hyper activated, it plays a pivotal role in the pathophysiology of many neurological diseases, as it can also be a source of additional injury to host cells. Since neurons lack the ability to divide and recover poorly from injury, they are extremely vulnerable to auto destructive immune and inflammatory processes, and this side effect is fundamental to the outcome of neurological diseases. Inappropriate immune responses are responsible for diseases such as Multiple Sclerosis (MS), Alzheimer's disease (AD) or Parkinson's disease (PD) and for the increased disability after brain trauma or stroke. However, in certain circumstances immune responses in the brain might have a neuroprotective effect, possibly mediated by the release of trophic factors from inflammatory and/or glial cells. The nerve growth factor (NGF) was the first neurotrophin discovered for its stimulatory effect on differentiation, survival, and growth of neurons in peripheral and central nervous system. This factor can protect axons and myelin from inflammatory damage and also can modulate the immune system, reducing the enhanced excitotoxicity during acute inflammatory activation. Therefore, because its neuroprotective activity and immunomodulatory effects, NGF may represent a new therapeutic approach for the treatment of numerous brain disorders. PMID:21701990

Colafrancesco, Valeria; Villoslada, Pablo

2011-06-01

250

T cell-specific inhibition of multiple apoptotic pathways blocks negative selection and causes autoimmunity  

PubMed Central

T cell self-tolerance is thought to involve peripheral tolerance and negative selection, involving apoptosis of autoreactive thymocytes. However, evidence supporting an essential role for negative selection is limited. Loss of Bim, a Bcl-2 BH3-only protein essential for thymocyte apoptosis, rarely results in autoimmunity on the C57BL/6 background. Mice with T cell-specific over-expression of Bcl-2, that blocks multiple BH3-only proteins, are also largely normal. The nuclear receptor Nur77, also implicated in negative selection, might function redundantly to promote apoptosis by associating with Bcl-2 and exposing its potentially pro-apoptotic BH3 domain. Here, we report that T cell-specific expression of a Bcl2 BH3 mutant transgene results in enhanced rescue of thymocytes from negative selection. Concomitantly, Treg development is increased. However, aged BH3 mutant mice progressively accumulate activated, autoreactive T cells, culminating in development of multi-organ autoimmunity and lethality. These data provide strong evidence that negative selection is crucial for establishing T cell tolerance. DOI: http://dx.doi.org/10.7554/eLife.03468.001 PMID:25182415

Burger, Megan L; Leung, Kenneth K; Bennett, Margaux J; Winoto, Astar

2014-01-01

251

Targeting MAGO proteins with a peptide aptamer reinforces their essential roles in multiple rice developmental pathways.  

PubMed

Peptide aptamers are artificial short peptides that potentially interfere with the biological roles of their target proteins; however, this technology has not yet been applied to plant functional genomics. MAGO and Y14, the two core subunits of the exon junction complex (EJC), form obligate heterodimers in eukaryotes. In Oryza sativa L. (rice), each of the two genes has two homologs, designated OsMAGO1 and OsMAGO2, and OsY14a and OsY14b, respectively. Here, we characterized a 16-amino acida peptide aptamer (PAP) for the rice MAGO proteins. PAP and rice Y14 bound competitively to rice MAGO proteins. Specifically targeting the MAGO proteins by expressing the aptamer in transgenic rice plants did not affect the endogenous synthesis and accumulation of MAGO proteins; however, the phenotypic variations observed in multiple organs phenocopied those of transgenic rice plants harboring RNA interference (RNAi) constructs in which the accumulation of MAGO and/or OsY14a transcripts and MAGO proteins was downregulated severely. Morphologically, the aptamer transgenic plants were short with abnormally developed flowers, and the stamens exhibited reduced degradation and absorption of both the endothecium and tapetum, thus confirming that EJC core heterodimers play essential roles in rice development, growth and reproduction. This study reveals that as a complementary approach of RNAi, peptide aptamers are powerful tools for interfering with the function of proteins in higher plants. PMID:25230811

Gong, Pichang; Quan, Hui; He, Chaoying

2014-12-01

252

The requirement for recombination factors differs considerably between different pathways of homologous double-strand break repair in somatic plant cells.  

PubMed

In recent years, multiple factors involved in DNA double-strand break (DSB) repair have been characterised in Arabidopsis thaliana. Using homologous sequences in somatic cells, DSBs are mainly repaired by two different pathways: synthesis-dependent strand annealing (SDSA) and single-strand annealing (SSA). By applying recombination substrates in which recombination is initiated by the induction of a site-specific DSB by the homing endonuclease I-SceI, we were able to characterise the involvement of different factors in both pathways. The nucleases MRE11 and COM1, both involved in DSB end processing, were not required for either SDSA or SSA in our assay system. Both SDSA and SSA were even more efficient without MRE11, in accordance with the fact that a loss of MRE11 might negatively affect the efficiency of non-homologous end joining. Loss of the classical recombinase RAD51 or its two paralogues RAD51C and XRCC3, as well as the SWI2/SNF2 remodelling factor RAD54, resulted in a drastic deficiency in SDSA but had hardly any influence on SSA, confirming that a strand exchange reaction is only required for SDSA. The helicase FANCM, which is postulated to be involved in the stabilisation of recombination intermediates, is surprisingly not only needed for SDSA but to a lesser extent also for SSA. Both SSA and SDSA were affected only weakly when the SMC6B protein, implicated in sister chromatid recombination, was absent, indicating that SSA and SDSA are in most cases intrachromatid recombination reactions. PMID:22860689

Roth, Nadine; Klimesch, Jacqueline; Dukowic-Schulze, Stefanie; Pacher, Michael; Mannuss, Anja; Puchta, Holger

2012-12-01

253

Assessing data quality for a federal environmental restoration project: Rationalizing the requirements of multiple clients  

SciTech Connect

Most environmental restoration projects at federal facilities face the difficult task of melding the quality assurance (QA) requirements of multiple clients, as well as dealing with historical data that are often of unknown quality. At Lawrence Livermore National Laboratory (LLNL), we have successfully integrated the requirements of our multiple clients by carefully developing a QA program that efficiently meets our clients` needs. The Site 300 Experimental Test Site is operated by LLNL in support of its national defense program. The responsibility for conducting environmental contaminant investigations and restoration at Site 300 is vested in the Site 300 Environmental Restoration Project (Site 300 ERP) of LLNL`s Environmental Restoration Division. LLNL Site 300 ERP must comply with the QA requirements of several clients, which include: the LLNL Environmental Protection Department, the DOE, the US Environmental Protection Agency-Region IX (EPA), the California Regional Water Quality Control Board -- Central Valley Region, and the California Department of Toxic Substances Control. This comprehensive QA program was used to determine the acceptability of historical data. The Site 300 ERP began soil and ground water investigations in 1982. However, we did not begin receiving analytical quality assurance/quality control (QA/QC) data until 1989; therefore, the pre-1989 data that were collected are of unknown quality. The US EPA QAMS-005/80 defines data quality as the totality of features and characteristics of data that bears on its ability to satisfy a given purpose. In the current context, the characteristics of major importance are accuracy, precision, completeness, representativeness, and comparability. Using our established QA program, we determined the quality of this historical data based on its comparability to the post-1989 data. By accepting this historical data, we were able to save a considerable amount of money in recharacterization costs.

Kiszka, V.R.; Carlsen, T.M.

1994-07-01

254

The Hippo signaling pathway is required for salivary gland development and its dysregulation is associated with Sjogren's-like disease  

PubMed Central

Sjogren's syndrome (SS) is a complex autoimmune disease that primarily affects salivary and lacrimal glands and is associated with high morbidity. Although the prevailing dogma is that immune system pathology drives SS, increasing evidence points to structural defects, including defective E-cadherin adhesion, to be involved in its etiology. We have shown that E-cadherin plays pivotal roles in the development of the mouse salivary submandibular gland (SMG) by organizing apical-basal polarity in acinar and ductal progenitors and by signaling survival for differentiating duct cells. Recently, E-cadherin junctions have been shown to interact with effectors of the Hippo signaling pathway, a core pathway regulating organ size, cell proliferation and differentiation. We now show that Hippo signaling is required for SMG branching morphogenesis and is involved in the pathophysiology of SS. During SMG development, a Hippo pathway effector, TAZ, becomes increasingly phosphorylated and associated with E-cadherin and ?-catenin, consistent with the activation of Hippo signaling. Inhibition of Lats2, an upstream kinase that promotes TAZ phosphorylation, results in dysmorphogenesis of the SMG and impaired duct formation. SMGs from NOD mice, a mouse model for SS, phenocopy the Lats2-inhibited SMGs and exhibit a reduction in E-cadherin junctional components, including TAZ. Importantly, labial specimens from human SS patients display mislocalization of TAZ from junctional regions to the nucleus, coincident with accumulation of extracellular matrix components, fibronectin and CTGF, known downstream targets of TAZ. Our studies show that Hippo signaling plays a crucial role in SMG branching morphogenesis and provide evidence that defects in this pathway are associated with SS in humans. PMID:24080911

Enger, Tone Berge; Samad-Zadeh, Arman; Bouchie, Meghan; Skarstein, Kathrine; Galtung, Hilde Kanli; Mera, Toshiyuki; Walker, Janice; Menko, A. Sue; Varelas, Xaralabos; Faustman, Denise L.; Jensen, Janicke Liaaen; Kukuruzinska, Maria

2013-01-01

255

Gambogic acid inhibits multiple myeloma mediated osteoclastogenesis through suppression of chemokine receptor CXCR4 signaling pathways.  

PubMed

Bone disease, characterized by the presence of lytic lesions and osteoporosis is the hallmark of multiple myeloma (MM). Stromal cell-derived factor 1? (SDF-1?) and its receptor, CXC chemokine receptor 4 (CXCR4), has been implicated as a regulator of bone resorption, suggesting that agents that can suppress SDF1?/CXCR4 signaling might inhibit osteoclastogenesis, a process closely linked to bone resorption. We, therefore, investigated whether gambogic acid (GA), a xanthone, could inhibit CXCR4 signaling and suppress osteoclastogenesis induced by MM cells. Through docking studies we predicted that GA directly interacts with CXCR4. This xanthone down-regulates the expression of CXCR4 on MM cells in a dose- and time-dependent manner. The down-regulation of CXCR4 was not due to proteolytic degradation, but rather GA suppresses CXCR4 mRNA expression by inhibiting nuclear factor-kappa B (NF-?B) DNA binding. This was further confirmed by quantitative chromatin immunoprecipitation assay, as GA inhibits p65 binding at the CXCR4 promoter. GA suppressed SDF-1?-induced chemotaxis of MM cells and downstream signaling of CXCR4 by inhibiting phosphorylation of Akt, p38, and Erk1/2 in MM cells. GA abrogated the RANKL-induced differentiation of macrophages to osteoclasts in a dose- and time-dependent manner. In addition, we found that MM cells induced differentiation of macrophages to osteoclasts, and that GA suppressed this process. Importantly, suppression of osteoclastogenesis by GA was mediated through IL-6 inhibition. Overall, our results show that GA is a novel inhibitor of CXCR4 expression and has a strong potential to suppress osteoclastogenesis mediated by MM cells. PMID:25034231

Pandey, Manoj K; Kale, Vijay P; Song, Chunhua; Sung, Shen-shu; Sharma, Arun K; Talamo, Giampaolo; Dovat, Sinisa; Amin, Shantu G

2014-10-01

256

Mesenchymal stem cells inhibit multiple myeloma cells via the Fas/Fas ligand pathway  

PubMed Central

Introduction Cell-based therapy represents a new frontier in the treatment of a wide variety of human diseases traditionally associated with morbidity outcomes, including those involving inflammation, autoimmunity, tissue damage, and cancer. However, the use of mesenchymal stem cells (MSCs) to treat multiple myeloma (MM) bone disease has raised concerns. Specifically, evidence has shown that infused MSCs might support tumor growth and metastasis. Methods In this study, we used a standard disseminated MM model in mice to identify the in vivo effects of intravenous MSC infusion. In addition, a series of in vitro co-culture assays were preformed to explore whether Fas/Fas ligand (Fas-L) is involved in the inhibitory effects of MSCs on MM cells. Results In the MM mouse model, treatment of MSCs with highly expressed Fas ligand (Fas-Lhigh MSCs) showed remarkable inhibitory effects on MM indenization in terms of extending the mouse survival rate and inhibiting tumor growth, bone resorption in the lumbus and collum femoris, and MM cell metastasis in the lungs and kidneys. In addition, reduced proliferation and increased apoptosis of MM cells was observed when co-cultured with Fas-Lhigh MSCs in vitro. Furthermore, mechanistically, the binding between Fas and Fas-L significantly induced apoptosis in MM cells, as evidenced through an increase in the expression of apoptosis marker and Fas in MM cells. In contrast, Fas-Lnull MSCs promote MM growth. Conclusions These data suggest that Fas/Fas-L-induced MM apoptosis plays a crucial role in the MSC-based inhibition of MM growth. Although whether MSCs inhibit or promote cancer growth remains controversial, the levels of Fas-L expression in MSCs determine, at least partially, the effects of MSCs on MM cell growth. PMID:24025590

2013-01-01

257

Inquiry in Conversation: Exploring the Multiple Solution Pathway (MSP) Lesson Structure as a Means to Progressive Discourse in the Science Classroom  

ERIC Educational Resources Information Center

This exploratory, descriptive study examined the way five chemistry teachers from four different schools enacted their visions of an activity labeled as the multiple solution pathway (MSP) lesson structure--one in which students were given a relevant problem to solve and the opportunity to propose and explore several solutions to the problem. A…

Criswell, Brett A.

2009-01-01

258

Multiple Folding Pathways for the P4-P6 RNA Domain Scott K. Silverman,*, Michael L. Deras, Sarah A. Woodson, Stephen A. Scaringe,| and Thomas R. Cech*,,  

E-print Network

-nucleotide P4-P6 domain of the Tetrahymena group I intron RNA, using stopped-flow fluorescence with 1 ms timeMultiple Folding Pathways for the P4-P6 RNA Domain Scott K. Silverman,*, Michael L. Deras,§ Sarah A ABSTRACT: We recently described site-specific pyrene labeling of RNA to monitor Mg2+-dependent equilibrium

Silverman, Scott K.

259

Multiple Pathways Are Co-regulated by the Protein Kinase Snf1 and the Transcription Factors Adr1 and Cat8*S  

E-print Network

Multiple Pathways Are Co-regulated by the Protein Kinase Snf1 and the Transcription Factors Adr1 shifted to the aerobic oxidation of non-fermentable carbon sources. The Snf1 protein ki- nase complex on the Snf1 protein kinase for derepression. Many more genes are SNF1-de- pendent than are either ADR1

260

Evidence for Multiple Export Pathways of Mercury from the Inoperative New Idria Hg Mine, CA  

NASA Astrophysics Data System (ADS)

Understanding mercury transport from inoperative Hg mines is important for California because of the presence of nearly 2,000 abandoned Hg mines in the California Coast Range. Since its closure in 1972, the New Idria Hg mine has developed an extensive acid mine drainage (AMD) system (pH 3) that drains into the San Carlos Creek (pH 9) about 100m downstream of a mine tailings pile. Sediment samples along the AMD system were analyzed using synchrotron radiation-based X-ray fluorescence (XRF), ?-X-ray absorption near edge structure (?-XANES) spectroscopy, extended X-ray absorption fine structure (EXAFS) spectroscopy, and sequential chemical extractions (SCE). It was determined by XRF mapping that Hg within the AMD settling pond sediments occurs mostly as colloids ranging in size from 1-10 ?m. Hg speciation of the colloids, determined by ?-XANES and EXAFS, consisted of 80% ?-HgS and 20% ?-HgS. SCE analysis of sediments along the entire AMD system resulted in the HgS fraction comprising >95% of the total Hg, suggesting minor Hg adsorption. Even though liquid Hg(0) can be panned in the stream it was not detected by SCE, suggesting that liquid Hg(0) settles into deeper portions of the sediments than were sampled. Mercury volatilization to the atmosphere is the other main pathway for Hg release from the New Idria mine site. Analysis of three size fractions of calcine waste material exhibited an increase in Hg volatilization when exposed to light (>500 nm) over dark controls. Calcine size fractions of 500-2000 ?m, 75-125 ?m, and <45 ?m exhibited light:dark ratios of 1.7 ± 0.05, 3.7 ± 0.05, and 4.3 ± 0.1, respectively. A new low-temperature EXAFS technique to directly detect liquid Hg(0) within Hg-contaminated soils was used to determine that mercury speciation in the three size fractions consisted of ?-HgS, ?-HgS, Eglestonite, Montroydite, and liquid Hg(0). The samples with light:dark ratios of 3.7 and 4.3 contained 10% and 9% Hg(0), respectively, while the sample with the lowest ratio had no detectable liquid Hg(0). A plot of light:dark Hg flux ratios vs. % liquid Hg(0) of waste material from other Hg mine sites shows a linear relationship, suggesting that the light:dark ratio of gaseous Hg release from Hg mine sites is strongly influenced by the presence of elemental Hg in the sediments. Based on our results, Hg is being exported from the site as colloidal HgS in the AMD system and by volatilization of liquid Hg(0) present in waste material.

Jew, A. D.; Luong, P. N.; Kim, C. S.; Rytuba, J. J.; Gustin, M. S.; Brown, G. E.

2009-12-01

261

A mitogen-responsive promoter region that is synergistically activated through multiple signalling pathways.  

PubMed Central

A regulatory region of the human transferrin receptor gene promoter was found to be required for increased expression in response to serum or growth factors. This region contains two elements that appear to cooperate for full responsiveness. We found that sodium orthovanadate treatment of cells significantly activated expression of promoter constructs containing these elements. 12-O-Tetradecanoylphorbol-13-acetate alone induced a twofold increase in expression but acted synergistically with vanadate to generate a highly elevated level of expression. Dibutyryl cyclic AMP alone had no effect on expression, but when added together with vanadate and 12-O-tetradecanoylphorbol-13-acetate, led to superinduction of the promoter construct. Induction of expression by these reagents was delayed several hours, and the kinetics were identical to those observed for serum induction. Images PMID:8382776

Ouyang, Q; Bommakanti, M; Miskimins, W K

1993-01-01

262

Identification and Analyses of AUX-IAA target genes controlling multiple pathways in developing fiber cells of Gossypium hirsutum L  

PubMed Central

Technological development led to an increased interest in systems biological approaches in plants to characterize developmental mechanism and candidate genes relevant to specific tissue or cell morphology. AUX-IAA proteins are important plant-specific putative transcription factors. There are several reports on physiological response of this family in Arabidopsis but in cotton fiber the transcriptional network through which AUX-IAA regulated its target genes is still unknown. in-silico modelling of cotton fiber development specific gene expression data (108 microarrays and 22,737 genes) using Algorithm for the Reconstruction of Accurate Cellular Networks (ARACNe) reveals 3690 putative AUX-IAA target genes of which 139 genes were known to be AUX-IAA co-regulated within Arabidopsis. Further AUX-IAA targeted gene regulatory network (GRN) had substantial impact on the transcriptional dynamics of cotton fiber, as showed by, altered TF networks, and Gene Ontology (GO) biological processes and metabolic pathway associated with its target genes. Analysis of the AUX-IAA-correlated gene network reveals multiple functions for AUX-IAA target genes such as unidimensional cell growth, cellular nitrogen compound metabolic process, nucleosome organization, DNA-protein complex and process related to cell wall. These candidate networks/pathways have a variety of profound impacts on such cellular functions as stress response, cell proliferation, and cell differentiation. While these functions are fairly broad, their underlying TF networks may provide a global view of AUX-IAA regulated gene expression and a GRN that guides future studies in understanding role of AUX-IAA box protein and its targets regulating fiber development. PMID:24497725

Nigam, Deepti; Sawant, Samir V

2013-01-01

263

Multiple Tumor Suppressor microRNAs Regulate Telomerase and TCF7, an Important Transcriptional Regulator of the Wnt Pathway  

PubMed Central

The human TERT (hTERT) gene encodes the telomerase catalytic subunit which plays a role in telomerase regulation. Telomerase is activated in more than 90% of all human malignancies and understanding how telomerase is regulated is necessary for implementation of successful anti-cancer therapies. microRNAs (miRNAs) are important regulators of gene expression in eukaryotic cells but evidence of their role in telomerase regulation has not been documented. To determine whether hTERT activity is regulated by multiple miRNAs, eight miRNAs which have putative binding sites in the hTERT 3?UTR together with miR-138-5p were evaluated in luciferase assays with a reporter containing the hTERT 3?UTR. Six miRNAs (let-7g*, miR-133a, miR-138-5p, miR-342-5p, miR-491-5p, and miR-541-3p) specifically inhibited the expression of the reporter luciferase-driven constructs and let-7g*, miR-133a, miR-138-5p, and miR-491-5p also downregulated endogenous telomerase activity in cells. Moreover, all six miRNAs significantly inhibited cell proliferation. miRNAs (miR-133a, miR-138-5p, 342-5p, 491-5p, 541-3p) also have predicted binding sites within the 3?UTR of three genes involved in Wnt signaling (TCF7, MSI1, and PAX5). These miRNAs inhibited the expression of the luciferase reporter constructs containing 3?UTRs of these genes and downregulated protein expression of the TCF7 transcription factor, which mediates the canonical Wnt pathway. Together, these results suggest the existence of a miRNA regulatory network involving the hTERT and Wnt pathway. PMID:24551047

Bargmann, William; Bose, Henry R.

2014-01-01

264

Uterine Rbpj is required for embryonic-uterine orientation and decidual remodeling via Notch pathway-independent and -dependent mechanisms.  

PubMed

Coordinated uterine-embryonic axis formation and decidual remodeling are hallmarks of mammalian post-implantation embryo development. Embryonic-uterine orientation is determined at initial implantation and synchronized with decidual development. However, the molecular mechanisms controlling these events remain elusive despite its discovery a long time ago. In the present study, we found that uterine-specific deletion of Rbpj, the nuclear transducer of Notch signaling, resulted in abnormal embryonic-uterine orientation and decidual patterning at post-implantation stages, leading to substantial embryo loss. We further revealed that prior to embryo attachment, Rbpj confers on-time uterine lumen shape transformation via physically interacting with uterine estrogen receptor (ER?) in a Notch pathway-independent manner, which is essential for the initial establishment of embryo orientation in alignment with uterine axis. While at post-implantation stages, Rbpj directly regulates the expression of uterine matrix metalloproteinase in a Notch pathway-dependent manner, which is required for normal post-implantation decidual remodeling. These results demonstrate that uterine Rbpj is essential for normal embryo development via instructing the initial embryonic-uterine orientation and ensuring normal decidual patterning in a stage-specific manner. Our data also substantiate the concept that normal mammalian embryonic-uterine orientation requires proper guidance from developmentally controlled uterine signaling. PMID:24971735

Zhang, Shuang; Kong, Shuangbo; Wang, Bingyan; Cheng, Xiaohong; Chen, Yongjie; Wu, Weiwei; Wang, Qiang; Shi, Junchao; Zhang, Ying; Wang, Shumin; Lu, Jinhua; Lydon, John P; DeMayo, Francesco; Pear, Warren S; Han, Hua; Lin, Haiyan; Li, Lei; Wang, Hongmei; Wang, Yan-Ling; Li, Bing; Chen, Qi; Duan, Enkui; Wang, Haibin

2014-08-01

265

Uterine Rbpj is required for embryonic-uterine orientation and decidual remodeling via Notch pathway-independent and -dependent mechanisms  

PubMed Central

Coordinated uterine-embryonic axis formation and decidual remodeling are hallmarks of mammalian post-implantation embryo development. Embryonic-uterine orientation is determined at initial implantation and synchronized with decidual development. However, the molecular mechanisms controlling these events remain elusive despite its discovery a long time ago. In the present study, we found that uterine-specific deletion of Rbpj, the nuclear transducer of Notch signaling, resulted in abnormal embryonic-uterine orientation and decidual patterning at post-implantation stages, leading to substantial embryo loss. We further revealed that prior to embryo attachment, Rbpj confers on-time uterine lumen shape transformation via physically interacting with uterine estrogen receptor (ER?) in a Notch pathway-independent manner, which is essential for the initial establishment of embryo orientation in alignment with uterine axis. While at post-implantation stages, Rbpj directly regulates the expression of uterine matrix metalloproteinase in a Notch pathway-dependent manner, which is required for normal post-implantation decidual remodeling. These results demonstrate that uterine Rbpj is essential for normal embryo development via instructing the initial embryonic-uterine orientation and ensuring normal decidual patterning in a stage-specific manner. Our data also substantiate the concept that normal mammalian embryonic-uterine orientation requires proper guidance from developmentally controlled uterine signaling. PMID:24971735

Zhang, Shuang; Kong, Shuangbo; Wang, Bingyan; Cheng, Xiaohong; Chen, Yongjie; Wu, Weiwei; Wang, Qiang; Shi, Junchao; Zhang, Ying; Wang, Shumin; Lu, Jinhua; Lydon, John P; DeMayo, Francesco; Pear, Warren S; Han, Hua; Lin, Haiyan; Li, Lei; Wang, Hongmei; Wang, Yan-ling; Li, Bing; Chen, Qi; Duan, Enkui; Wang, Haibin

2014-01-01

266

Simulating evolution by gene duplication of protein features that require multiple amino acid residues  

PubMed Central

Gene duplication is thought to be a major source of evolutionary innovation because it allows one copy of a gene to mutate and explore genetic space while the other copy continues to fulfill the original function. Models of the process often implicitly assume that a single mutation to the duplicated gene can confer a new selectable property. Yet some protein features, such as disulfide bonds or ligand binding sites, require the participation of two or more amino acid residues, which could require several mutations. Here we model the evolution of such protein features by what we consider to be the conceptually simplest route—point mutation in duplicated genes. We show that for very large population sizes N, where at steady state in the absence of selection the population would be expected to contain one or more duplicated alleles coding for the feature, the time to fixation in the population hovers near the inverse of the point mutation rate, and varies sluggishly with the ?th root of 1/N, where ? is the number of nucleotide positions that must be mutated to produce the feature. At smaller population sizes, the time to fixation varies linearly with 1/N and exceeds the inverse of the point mutation rate. We conclude that, in general, to be fixed in 108 generations, the production of novel protein features that require the participation of two or more amino acid residues simply by multiple point mutations in duplicated genes would entail population sizes of no less than 109. PMID:15340163

Behe, Michael J.; Snoke, David W.

2004-01-01

267

RNAi screening reveals requirement for host cell secretory pathway in infection by diverse families of negative-strand RNA viruses  

PubMed Central

Negative-strand (NS) RNA viruses comprise many pathogens that cause serious diseases in humans and animals. Despite their clinical importance, little is known about the host factors required for their infection. Using vesicular stomatitis virus (VSV), a prototypic NS RNA virus in the family Rhabdoviridae, we conducted a human genome-wide siRNA screen and identified 72 host genes required for viral infection. Many of these identified genes were also required for infection by two other NS RNA viruses, the lymphocytic choriomeningitis virus of the Arenaviridae family and human parainfluenza virus type 3 of the Paramyxoviridae family. Genes affecting different stages of VSV infection, such as entry/uncoating, gene expression, and assembly/release, were identified. Depletion of the proteins of the coatomer complex I or its upstream effectors ARF1 or GBF1 led to detection of reduced levels of VSV RNA. Coatomer complex I was also required for infection of lymphocytic choriomeningitis virus and human parainfluenza virus type 3. These results highlight the evolutionarily conserved requirements for gene expression of diverse families of NS RNA viruses and demonstrate the involvement of host cell secretory pathway in the process. PMID:22065774

Panda, Debasis; Das, Anshuman; Dinh, Phat X.; Subramaniam, Sakthivel; Nayak, Debasis; Barrows, Nicholas J.; Pearson, James L.; Thompson, Jesse; Kelly, David L.; Ladunga, Istvan; Pattnaik, Asit K.

2011-01-01

268

Multiplication  

NSDL National Science Digital Library

Here are some fun games to make practicing multiplication fun!!! Before you start the fun... click Multiplication Tables to review what you already know! Can you figure out the Multiplication Hidden Picture... you better know your math skills first or the picture will burst! It\\'s times to have a \\"blast\\"... Blow me away with theMultiplication Tunnel Blaster Now your ready to join the team! Show me ...

Walker, Ms.

2008-03-26

269

Characterization of an ERAD pathway for non-glycosylated BiP substrates which requires Herp  

PubMed Central

SUMMARY To investigate the disposal of non-glycosylated BiP substrates, we used a non-secreted ? LC, which exists in a partially (ox1) and completely (ox2) oxidized state. The ox2 form is partially reduced in order to be degraded and only the ox1 form is ubiquitinated and associates with both Herp, and Derlin-1. Herp is in a complex with ubiquitinated proteins and with the 26S proteasome, suggesting that it plays a role in linking substrates with the proteasome. Over-expressed Herp also interacts with two other BiP substrates but not with two calnexin substrates. Either expression of p97 or Hrd1 mutants, which are in a complex with Herp and Derlin-1, or reducing Herp levels inhibited the degradation of the BiP substrates, whereas the latter had no effect on the degradation of the calnexin substrates. This suggests that there is some distinction in the pathways used to dispose of these two types of ERAD substrates. PMID:18042451

Okuda-Shimizu, Yuki; Hendershot, Linda M.

2007-01-01

270

Klf5 Deletion Promotes Pten Deletion–Initiated Luminal-Type Mouse Prostate Tumors through Multiple Oncogenic Signaling Pathways12  

PubMed Central

Krüppel-like factor 5 (KLF5) regulates multiple biologic processes. Its function in tumorigenesis appears contradictory though, showing both tumor suppressor and tumor promoting activities. In this study, we examined whether and how Klf5 functions in prostatic tumorigenesis using mice with prostate-specific deletion of Klf5 and phosphatase and tensin homolog (Pten), both of which are frequently inactivated in human prostate cancer. Histologic analysis demonstrated that when one Pten allele was deleted, which causes mouse prostatic intraepithelial neoplasia (mPIN), Klf5 deletion accelerated the emergence and progression of mPIN. When both Pten alleles were deleted, which causes prostate cancer, Klf5 deletion promoted tumor growth, increased cell proliferation, and caused more severe morphologic and molecular alterations. Homozygous deletion of Klf5 was more effective than hemizygous deletion. Unexpectedly, while Pten deletion alone expanded basal cell population in a tumor as reported, Klf5 deletion in the Pten-null background clearly reduced basal cell population while expanding luminal cell population. Global gene expression profiling, pathway analysis, and experimental validation indicate that multiple mechanisms could mediate the tumor-promoting effect of Klf5 deletion, including the up-regulation of epidermal growth factor and its downstream signaling molecules AKT and ERK and the inactivation of the p15 cell cycle inhibitor. KLF5 also appears to cooperate with several transcription factors, including CREB1, Sp1, Myc, ER and AR, to regulate gene expression. These findings validate the tumor suppressor function of KLF5. They also yield a mouse model that shares two common genetic alterations with human prostate cancer—mutation/deletion of Pten and deletion of Klf5. PMID:25425963

Xing, Changsheng; Ci, Xinpei; Sun, Xiaodong; Fu, Xiaoying; Zhang, Zhiqian; Dong, Eric N.; Hao, Zhao-Zhe; Dong, Jin-Tang

2014-01-01

271

A calmodulin-binding/CGCG box DNA-binding protein family involved in multiple signaling pathways in plants  

NASA Technical Reports Server (NTRS)

We reported earlier that the tobacco early ethylene-responsive gene NtER1 encodes a calmodulin-binding protein (Yang, T., and Poovaiah, B. W. (2000) J. Biol. Chem. 275, 38467-38473). Here we demonstrate that there is one NtER1 homolog as well as five related genes in Arabidopsis. These six genes are rapidly and differentially induced by environmental signals such as temperature extremes, UVB, salt, and wounding; hormones such as ethylene and abscisic acid; and signal molecules such as methyl jasmonate, H(2)O(2), and salicylic acid. Hence, they were designated as AtSR1-6 (Arabidopsis thaliana signal-responsive genes). Ca(2+)/calmodulin binds to all AtSRs, and their calmodulin-binding regions are located on a conserved basic amphiphilic alpha-helical motif in the C terminus. AtSR1 targets the nucleus and specifically recognizes a novel 6-bp CGCG box (A/C/G)CGCG(G/T/C). The multiple CGCG cis-elements are found in promoters of genes such as those involved in ethylene signaling, abscisic acid signaling, and light signal perception. The DNA-binding domain in AtSR1 is located on the N-terminal 146 bp where all AtSR1-related proteins share high similarity but have no similarity to other known DNA-binding proteins. The calmodulin-binding nuclear proteins isolated from wounded leaves exhibit specific CGCG box DNA binding activities. These results suggest that the AtSR gene family encodes a family of calmodulin-binding/DNA-binding proteins involved in multiple signal transduction pathways in plants.

Yang, Tianbao; Poovaiah, B. W.

2002-01-01

272

The housekeeping gene hypoxanthine guanine phosphoribosyltransferase (HPRT) regulates multiple developmental and metabolic pathways of murine embryonic stem cell neuronal differentiation.  

PubMed

The mechanisms by which mutations of the purinergic housekeeping gene hypoxanthine guanine phosphoribosyltransferase (HPRT) cause the severe neurodevelopmental Lesch Nyhan Disease (LND) are poorly understood. The best recognized neural consequences of HPRT deficiency are defective basal ganglia expression of the neurotransmitter dopamine (DA) and aberrant DA neuronal function. We have reported that HPRT deficiency leads to dysregulated expression of multiple DA-related developmental functions and cellular signaling defects in a variety of HPRT-deficient cells, including human induced pluripotent stem (iPS) cells. We now describe results of gene expression studies during neuronal differentiation of HPRT-deficient murine ESD3 embryonic stem cells and report that HPRT knockdown causes a marked switch from neuronal to glial gene expression and dysregulates expression of Sox2 and its regulator, genes vital for stem cell pluripotency and for the neuronal/glial cell fate decision. In addition, HPRT deficiency dysregulates many cellular functions controlling cell cycle and proliferation mechanisms, RNA metabolism, DNA replication and repair, replication stress, lysosome function, membrane trafficking, signaling pathway for platelet activation (SPPA) multiple neurotransmission systems and sphingolipid, sulfur and glycan metabolism. We propose that the neural aberrations of HPRT deficiency result from combinatorial effects of these multi-system metabolic errors. Since some of these aberrations are also found in forms of Alzheimer's and Huntington's disease, we predict that some of these systems defects play similar neuropathogenic roles in diverse neurodevelopmental and neurodegenerative diseases in common and may therefore provide new experimental opportunities for clarifying pathogenesis and for devising new potential therapeutic targets in developmental and genetic disease. PMID:24130677

Kang, Tae Hyuk; Park, Yongjin; Bader, Joel S; Friedmann, Theodore

2013-01-01

273

The Housekeeping Gene Hypoxanthine Guanine Phosphoribosyltransferase (HPRT) Regulates Multiple Developmental and Metabolic Pathways of Murine Embryonic Stem Cell Neuronal Differentiation  

PubMed Central

The mechanisms by which mutations of the purinergic housekeeping gene hypoxanthine guanine phosphoribosyltransferase (HPRT) cause the severe neurodevelopmental Lesch Nyhan Disease (LND) are poorly understood. The best recognized neural consequences of HPRT deficiency are defective basal ganglia expression of the neurotransmitter dopamine (DA) and aberrant DA neuronal function. We have reported that HPRT deficiency leads to dysregulated expression of multiple DA-related developmental functions and cellular signaling defects in a variety of HPRT-deficient cells, including human induced pluripotent stem (iPS) cells. We now describe results of gene expression studies during neuronal differentiation of HPRT-deficient murine ESD3 embryonic stem cells and report that HPRT knockdown causes a marked switch from neuronal to glial gene expression and dysregulates expression of Sox2 and its regulator, genes vital for stem cell pluripotency and for the neuronal/glial cell fate decision. In addition, HPRT deficiency dysregulates many cellular functions controlling cell cycle and proliferation mechanisms, RNA metabolism, DNA replication and repair, replication stress, lysosome function, membrane trafficking, signaling pathway for platelet activation (SPPA) multiple neurotransmission systems and sphingolipid, sulfur and glycan metabolism. We propose that the neural aberrations of HPRT deficiency result from combinatorial effects of these multi-system metabolic errors. Since some of these aberrations are also found in forms of Alzheimer's and Huntington's disease, we predict that some of these systems defects play similar neuropathogenic roles in diverse neurodevelopmental and neurodegenerative diseases in common and may therefore provide new experimental opportunities for clarifying pathogenesis and for devising new potential therapeutic targets in developmental and genetic disease. PMID:24130677

Bader, Joel S.; Friedmann, Theodore

2013-01-01

274

AtGSNOR1 function is required for multiple developmental programs in Arabidopsis.  

PubMed

Nitric oxide (NO) has been proposed to regulate a diverse array of activities during plant growth, development and immune function. S-nitrosylation, the addition of an NO moiety to a reactive cysteine thiol, to form an S-nitrosothiol (SNO), is emerging as a prototypic redox-based post-translational modification. An ARABIDOPSIS THALIANA S-NITROSOGLUTATHIONE (GSNO) REDUCTASE (AtGSNOR1) is thought to be the major regulator of total cellular SNO levels in this plant species. Here, we report on the impact of loss- and gain-of-function mutations in AtGSNOR1 upon plant growth and development. Loss of AtGSNOR1 function in atgsnor1-3 plants increased the number of initiated higher order axillary shoots that remain active, resulting in a loss of apical dominance relative to wild type. In addition atgsnor1-3 affected leaf shape, germination, 2,4-D sensitivity and reduced hypocotyl elongation in both light and dark grown seedlings. Silique size and seed production were also decreased in atgsnor1-3 plants and the latter was reduced in atgsnor1-1 plants, which overexpress AtGSNOR1. Overexpression of AtGSNOR1 slightly delayed flowering time in both long and short days, whereas atgsnor1-3 showed early flowering compared to wild type. In the atgsnor1-3 line, FLOWERING LOCUS C (FLC) expression was reduced, whereas transcription of CONSTANS (CO) was enhanced. Therefore, AtGSNOR1 may negatively regulate the autonomous and photoperiod flowering time pathways. Both overexpression and loss of AtGSNOR1 function also reduced primary root growth, while root hair development was increased in atgsnor1-1 and reduced in atgsnor1-3 plants. Collectively, our findings imply that AtGSNOR1 controls multiple genetic networks integral to plant growth and development. PMID:22767201

Kwon, Eunjung; Feechan, Angela; Yun, Byung-Wook; Hwang, Byung-Ho; Pallas, Jacqueline A; Kang, Jeong-Gu; Loake, Gary J

2012-09-01

275

A genome-wide siRNA screen reveals multiple mTORC1 independent signaling pathways regulating autophagy under normal nutritional conditions  

PubMed Central

Summary Autophagy is a cellular catabolic mechanism that plays an essential function in protecting multicellular eukaryotes from neurodegeneration, cancer and other diseases. However, we still know very little about mechanisms regulating autophagy under normal homeostatic conditions when nutrients are not limiting. In a genome-wide human siRNA screen, we demonstrate that under normal nutrient conditions up regulation of autophagy requires the type III PI3 kinase, but not inhibition of mTORC1, the essential negative regulator of starvation-induced autophagy. We show that a group of growth factors and cytokines inhibit the type III PI3 kinase through multiple pathways, including the MAPK-ERK1/2, Stat3, Akt/Foxo3 and CXCR4/GPCR, which are all known to positively regulate cell growth and proliferation. Our study suggests that the type III PI3 kinase integrates diverse signals to regulate cellular levels of autophagy, and that autophagy and cell proliferation may represent two alternative cell fates that are regulated in a mutually exclusive manner. PMID:20627085

Lipinski, Marta M.; Hoffman, Greg; Ng, Aylwin; Zhou, Wen; Py, Bénédicte F.; Hsu, Emily; Liu, Xuxin; Eisenberg, Jason; Liu, Jun; Blenis, John; Xavier, Ramnik J.; Yuan, Junying

2010-01-01

276

Canonical Wnt Pathway Inhibitor ICG-001 Induces Cytotoxicity of Multiple Myeloma Cells in Wnt-Independent Manner  

PubMed Central

Canonical Wnt signaling has been implicated in the regulation of multiple myeloma (MM) growth. Here, we investigated whether the targeting of this pathway with a novel pharmacological inhibitor ICG-001 would result in an anti-tumor effect and improvement of chemosensitivity in MM. As expected, ICG-001 specifically down-regulated ?-catenin/TCF-mediated transcription in MM cells. Treatment with ICG-001 resulted in growth arrest and apoptosis in MM cell lines and primary MM cells. Moreover, ICG-001 enhanced the cytotoxic effects of doxorubicin and melphalan and abrogated chemoresistance of MM cells to these chemotherapeutics induced by bone marrow stroma. The cytotoxic effect of ICG-001 was caspase-dependent and mediated through transcriptional up-regulation of BH3-only pro-apoptotic members of the Bcl-2 family Noxa and Puma but not through inhibition of canonical Wnt signaling. ICG-001 selectively induced apoptosis in primary MM cells but did not affect non-MM cells of the bone marrow microenvironment. Experiments using a xenograft model of MM showed substantial anti-tumor effects of this compound in vivo. Thus, our study demonstrated that the small molecule inhibitor ICG-001 has strong anti-MM effects and could be developed further for therapeutic intervention in this disease. PMID:25635944

Grigson, Eileen R.; Ozerova, Maria; Pisklakova, Alexandra; Liu, Hao; Sullivan, Daniel M.; Nefedova, Yulia

2015-01-01

277

Potent activity of carfilzomib, a novel, irreversible inhibitor of the ubiquitin-proteasome pathway, against preclinical models of multiple myeloma  

PubMed Central

The proteasome has emerged as an important target for cancer therapy with the approval of bortezomib, a first-in-class, reversible proteasome inhibitor, for relapsed/refractory multiple myeloma (MM). However, many patients have disease that does not respond to bortezomib, whereas others develop resistance, suggesting the need for other inhibitors with enhanced activity. We therefore evaluated a novel, irreversible, epoxomicin-related proteasome inhibitor, carfilzomib. In models of MM, this agent potently bound and specifically inhibited the chymotrypsin-like proteasome and immunoproteasome activities, resulting in accumulation of ubiquitinated substrates. Carfilzomib induced a dose- and time-dependent inhibition of proliferation, ultimately leading to apoptosis. Programmed cell death was associated with activation of c-Jun-N-terminal kinase, mitochondrial membrane depolarization, release of cytochrome c, and activation of both intrinsic and extrinsic caspase pathways. This agent also inhibited proliferation and activated apoptosis in patient-derived MM cells and neoplastic cells from patients with other hematologic malignancies. Importantly, carfilzomib showed increased efficacy compared with bortezomib and was active against bortezomib-resistant MM cell lines and samples from patients with clinical bortezomib resistance. Carfilzomib also overcame resistance to other conventional agents and acted synergistically with dexamethasone to enhance cell death. Taken together, these data provide a rationale for the clinical evaluation of carfilzomib in MM. PMID:17591945

Kuhn, Deborah J.; Chen, Qing; Voorhees, Peter M.; Strader, John S.; Shenk, Kevin D.; Sun, Congcong M.; Demo, Susan D.; Bennett, Mark K.; van Leeuwen, Fijs W. B.; Chanan-Khan, Asher A.

2007-01-01

278

Fluxes of Ca2+ and K+ Are Required for the Listeriolysin O-Dependent Internalization Pathway of Listeria monocytogenes  

PubMed Central

Listeria monocytogenes is responsible for the life-threatening food-borne disease listeriosis. This disease mainly affects elderly and immunocompromised individuals, causing bacteremia and meningoencephalitis. In pregnant women, L. monocytogenes infection leads to abortion and severe infection of the fetus or newborn. The L. monocytogenes intracellular life cycle is critical for pathogenesis. Previous studies have established that the major virulence factor of L. monocytogenes, the pore-forming toxin listeriolysin O (LLO), is sufficient to induce L. monocytogenes internalization into human epithelial cell lines. This internalization pathway strictly requires the formation of LLO pores in the plasma membrane and can be stimulated by the heterologous pore-forming toxin pneumolysin, suggesting that LLO acts nonspecifically by forming transmembrane pores. The present work tested the hypothesis that Ca2+ and K+ fluxes subsequent to perforation by LLO control L. monocytogenes internalization. We report that L. monocytogenes perforates the host cell plasma membrane in an LLO-dependent fashion at the early stage of invasion. In response to perforation, host cells undergo Ca2+-dependent but K+-independent resealing of their plasma membrane. In contrast to the plasma membrane resealing process, LLO-induced L. monocytogenes internalization requires both Ca2+ and K+ fluxes. Further linking ion fluxes to bacterial internalization, treating cells with a combination of Ca2+ and K+ ionophores but not with individual ionophores is sufficient to induce efficient internalization of large cargoes, such as 1-?m polystyrene beads and bacteria. We propose that LLO-induced L. monocytogenes internalization requires a Ca2+- and K+-dependent internalization pathway that is mechanistically distinct from the process of plasma membrane resealing. PMID:24366251

Vadia, Stephen

2014-01-01

279

Higher biodiversity is required to sustain multiple ecosystem processes across temperature regimes  

PubMed Central

Biodiversity loss is occurring rapidly worldwide, yet it is uncertain whether few or many species are required to sustain ecosystem functioning in the face of environmental change. The importance of biodiversity might be enhanced when multiple ecosystem processes (termed multifunctionality) and environmental contexts are considered, yet no studies have quantified this explicitly to date. We measured five key processes and their combined multifunctionality at three temperatures (5, 10 and 15 °C) in freshwater aquaria containing different animal assemblages (1–4 benthic macroinvertebrate species). For single processes, biodiversity effects were weak and were best predicted by additive-based models, i.e. polyculture performances represented the sum of their monoculture parts. There were, however, significant effects of biodiversity on multifunctionality at the low and the high (but not the intermediate) temperature. Variation in the contribution of species to processes across temperatures meant that greater biodiversity was required to sustain multifunctionality across different temperatures than was the case for single processes. This suggests that previous studies might have underestimated the importance of biodiversity in sustaining ecosystem functioning in a changing environment. PMID:25131335

Perkins, Daniel M; Bailey, R A; Dossena, Matteo; Gamfeldt, Lars; Reiss, Julia; Trimmer, Mark; Woodward, Guy

2015-01-01

280

PP2A (Cdc)?? is required for multiple events during meiosis I.  

PubMed

Protein phosphatase 2A (PP2A) is a heterotrimer consisting of A and B regulatory subunits and a C catalytic subunit. PP2A regulates mitotic cell events that include the cell cycle, nutrient sensing, p53 stability and various mitogenic signals. The role of PP2A during meiosis is less understood. We explored the role of Saccharomyces cerevisiae PP2A during meiosis. We show a PP2A (Cdc)?? containing the human B/55 family B subunit ortholog, Cdc55, is required for progression through meiosis I. Mutant cells lacking Cdc55 remain mononucleated. They harbor meiotic gene expression, premeiotic DNA replication, homologous recombination and spindle pole body (SPB) defects. They initiate but do not complete replication and are defective in performing intergenic homologous recombination. Bypass alleles, which allow cells defective in recombination to finish meiosis, do not suppress the meiosis I defect. cdc55 cells arrest with a single SPB lacking microtubules, or duplicated but not separated SBPs containing microtubules. Finally, the premeiotic replication defect is suppressed by loss of Rad9 checkpoint function. We conclude PP2A (Cdc)?? is required for the proper temporal initiation of multiple meiotic events and/or monitors these events to ensure their fidelity. PMID:21455032

Nolt, Jocelyn K; Rice, Lyndi M; Gallo-Ebert, Christina; Bisher, Margaret E; Nickels, Joseph T

2011-05-01

281

P38 AND EGF RECEPTOR KINASE-MEDIATED ACTIVATION OF THE PHOSPHATIDYLINOSITOL 3-KINASE/AKT PATHWAY IS REQUIRED FOR ZN2+INDUCED CYCLOOXYGENASE-2 EXPRESSION  

EPA Science Inventory

Cyclooxygenase 2 (COX-2) expression is induced by physiological and inflammatory stimuli. Regulation of COX-2 expression is stimulus- and cell type-specific. Exposure to Zn2+ has been associated with activation of multiple intracellular signaling pathways as well as the induction...

282

Rigosertib as a selective anti-tumor agent can ameliorate multiple dysregulated signaling transduction pathways in high-grade myelodysplastic syndrome.  

PubMed

Rigosertib has demonstrated therapeutic activity for patients with high-risk myelodysplastic syndrome (MDS) in clinical trials. However, the role of rigosertib in MDS has not been thoroughly characterized. In this study, we found out that rigosertib induced apoptosis, blocked the cell cycle at the G2/M phase and subsequently inhibited the proliferation of CD34+ cells from MDS, while it minimally affected the normal CD34+ cells. Further studies showed that rigosertib acted via the activation of the P53 signaling pathway. Bioinformatics analysis based on gene expression profile and flow cytometry analysis revealed the abnormal activation of the Akt-PI3K, Jak-STAT and Wnt pathways in high-grade MDS, while the p38 MAPK, SAPK/JNK and P53 pathways were abnormally activated in low-grade MDS. Rigosertib could markedly inhibit the activation of the Akt-PI3K and Wnt pathways, whereas it activated the SAPK/JNK and P53 pathways in high-grade MDS. A receptor tyrosine kinase phosphorylation array demonstrated that rigosertib could increase the activation of RET and PDGFR-? while reducing the activation of Tie2 and VEGFR2 in MDS cells. Taken together, these data indicate that rigosertib is a selective and promising anti-tumor agent that could ameliorate multiple dysregulated signaling transduction pathways in high-grade MDS. PMID:25472472

Xu, Feng; He, Qi; Li, Xiao; Chang, Chun-Kang; Wu, Ling-Yun; Zhang, Zheng; Liu, Li; Shi, Wen-Hui; Zhu, Yang; Zhao, You-Shan; Gu, Shu-Cheng; Fei, Cheng-Ming; Guo, Juan; Wu, Dong; Zhou, Liyu

2014-01-01

283

Activation of the mTOR signalling pathway is required for pancreatic growth in protease-inhibitor-fed mice.  

PubMed

Cholecystokinin (CCK)-induced pancreatic growth in mice involves parallel increases in DNA and protein. The mammalian target of rapamycin (mTOR) signalling pathway regulates mRNA translation and its activation is implicated in growth of various tissues. The aim of this study was to elucidate whether mTOR activation is required for pancreatic growth in a mouse model of increased endogenous CCK release. In mice fed chow containing the synthetic protease inhibitor camostat, protein synthetic rates and phosphorylation of two downstream targets of mTOR, eukaryotic initiation factor 4E binding protein 1 (4E-BP1) and the ribosomal protein S6 (S6), increased in comparison with fasted controls. The camostat-induced increases in protein synthesis and 4E-BP1 and S6 phosphorylation were almost totally abolished by administration of the mTOR inhibitor rapamycin 1 h prior to camostat feeding. In contrast, the phosphorylation of ERK1/2 and JNK and the expression of the early response genes c-jun, c-fos, ATF3 and egr-1 induced by camostat feeding were not affected by rapamycin. In mice fed camostat for 7 days, the ratio of pancreatic to body weight increased by 143%, but when rapamycin was administered daily this was reduced to a 22% increase. Changes in pancreatic mass were paralleled by protein and DNA content following camostat feeding and rapamycin administration. Moreover, while BrdU incorporation, an indicator of DNA synthesis, was increased to 448% of control values after 2 days of camostat feeding, rapamycin administration completely inhibited this increase. We conclude that the mTOR signalling pathway is required for CCK-induced cell division and pancreatic growth. PMID:16613881

Crozier, Stephen J; Sans, M Dolors; Guo, LiLi; D'Alecy, Louis G; Williams, John A

2006-06-15

284

A melanin-independent interaction between Mc1r and Met signaling pathways is required for HGF-dependent melanoma.  

PubMed

Melanocortin 1 receptor (MC1R) signaling stimulates black eumelanin production through a cAMP-dependent pathway. MC1R polymorphisms can impair this process, resulting in a predominance of red phaeomelanin. The red hair, fair skin and UV sensitive phenotype is a well-described melanoma risk factor. MC1R polymorphisms also confer melanoma risk independent of pigment. We investigated the effect of Mc1r deficiency in a mouse model of UV-induced melanoma. C57BL/6-Mc1r(+/+) -HGF transgenic mice have a characteristic hyperpigmented black phenotype with extra-follicular dermal melanocytes located at the dermal/epidermal junction. UVB induces melanoma, independent of melanin pigmentation, but UVA-induced and spontaneous melanomas are dependent on black eumelanin. We crossed these mice with yellow C57BL/6-Mc1r(e/e) animals which have a non-functional Mc1r and produce predominantly yellow phaeomelanin. Yellow C57BL/6-Mc1r(e/e) -HGF mice produced no melanoma in response to UVR or spontaneously even though the HGF transgene and its receptor Met were expressed. Total melanin was less than in C57BL/6-Mc1r(+/+) -HGF mice, hyperpigmentation was not observed and there were few extra-follicular melanocytes. Thus, functional Mc1r was required for expression of the transgenic HGF phenotype. Heterozygous C57BL/6-Mc1r(e/+) -HGF mice were black and hyperpigmented and, although extra-follicular melanocytes and skin melanin content were similar to C57BL/6-Mc1r(+/+) -HGF animals, they developed UV-induced and spontaneous melanomas with significantly less efficiency by all criteria. Thus, heterozygosity for Mc1r was sufficient to restore the transgenic HGF phenotype but insufficient to fully restore melanoma. We conclude that a previously unsuspected melanin-independent interaction between Mc1r and Met signaling pathways is required for HGF-dependent melanoma and postulate that this pathway is involved in human melanoma. PMID:24975581

Wolnicka-Glubisz, Agnieszka; Strickland, Faith M; Wielgus, Albert; Anver, Miriam; Merlino, Glenn; De Fabo, Edward C; Noonan, Frances P

2015-02-15

285

Requirement for Both Shc and Phosphatidylinositol 3? Kinase Signaling Pathways in Polyomavirus Middle T-Mediated Mammary Tumorigenesis  

PubMed Central

Transgenic mice expressing the polyomavirus (PyV) middle T antigen (MT) develop multifocal mammary tumors which frequently metastasize to the lung. The potent transforming activity of PyV MT is correlated with its capacity to activate and associate with a number of signaling molecules, including the Src family tyrosine kinases, the 85-kDa Src homology 2 subunit of the phosphatidylinositol 3? (PI-3?) kinase, and the Shc adapter protein. To uncover the role of these signaling proteins in MT-mediated mammary tumorigenesis, we have generated transgenic mice that express mutant PyV MT antigens decoupled from either the Shc or the PI-3? kinase signaling pathway. In contrast to the rapid induction of metastatic mammary tumors observed in the strains expressing wild-type PyV MT, mammary epithelial cell-specific expression of either mutant PyV MT resulted in the induction of extensive mammary epithelial hyperplasias. The mammary epithelial hyperplasias expressing the mutant PyV MT defective in recruiting the PI-3? kinase were highly apoptotic, suggesting that recruitment of PI-3? kinase by MT affects cell survival. Whereas the initial phenotypes observed in both strains were global mammary epithelial hyperplasias, focal mammary tumors eventually arose in all female transgenic mice. Genetic and biochemical analyses of tumorigenesis in the transgenic strains expressing the PyV MT mutant lacking the Shc binding site revealed that a proportion of the metastatic tumors arising in these mice displayed evidence of reversion of the mutant Shc binding site. In contrast, no evidence of reversion of the PI-3? kinase binding site was noted in tumors derived from the strains expressing the PI-3? kinase binding site MT mutant. Tumor progression in both mutant strains was further correlated with upregulation of the epidermal growth factor receptor family members which are known to couple to the PI-3? kinase and Shc signaling pathways. Taken together, these observations suggest that PyV MT-mediated tumorigenesis requires activation of both Shc and PI-3? kinase, which appear to be required for stimulation of cell proliferation and survival signaling pathways, respectively. PMID:9528804

Webster, Marc A.; Hutchinson, John N.; Rauh, Michael J.; Muthuswamy, Senthil K.; Anton, Martina; Tortorice, Christopher G.; Cardiff, Robert D.; Graham, Frank L.; Hassell, John A.; Muller, William J.

1998-01-01

286

Identification of a gene required for membrane protein retention in the early secretory pathway.  

PubMed Central

The yeast SEC12 gene product (Sec12p) is an integral membrane protein required for the protein transport from the endoplasmic reticulum (ER) to the Golgi apparatus. Although this protein is almost exclusively localized in the ER, a significant fraction of Sec12p is modified by an enzyme that resides in the early compartment of the Golgi apparatus, suggesting that Sec12p is cycling between the ER and the early Golgi. We have taken a genetic approach to investigate the retention mechanism of Sec12p. Analysis of mutants that are defective in the retention of the Sec12-Mf alpha 1 fusion protein in the early secretory compartments has identified a gene, RER1. A recessive mutation in RER1 causes mislocalization of the authentic Sec12p as well as two different Sec12 fusion proteins to the late Golgi apparatus and even to the cell surface. However, the rer1 mutant is not defective in the retention of an ER-resident soluble protein, BiP, suggesting that soluble and membrane proteins are retained in the ER by distinct mechanisms. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:8367481

Nishikawa, S; Nakano, A

1993-01-01

287

Germ cells are not required to establish the female pathway in mouse fetal gonads.  

PubMed

The fetal gonad is composed of a mixture of somatic cell lineages and germ cells. The fate of the gonad, male or female, is determined by a population of somatic cells that differentiate into Sertoli or granulosa cells and direct testis or ovary development. It is well established that germ cells are not required for the establishment or maintenance of Sertoli cells or testis cords in the male gonad. However, in the agametic ovary, follicles do not form suggesting that germ cells may influence granulosa cell development. Prior investigations of ovaries in which pre-meiotic germ cells were ablated during fetal life reported no histological changes during stages prior to birth. However, whether granulosa cells underwent normal molecular differentiation was not investigated. In cases where germ cell loss occurred secondary to other mutations, transdifferentiation of granulosa cells towards a Sertoli cell fate was observed, raising questions about whether germ cells play an active role in establishing or maintaining the fate of granulosa cells. We developed a group of molecular markers associated with ovarian development, and show here that the loss of pre-meiotic germ cells does not disrupt the somatic ovarian differentiation program during fetal life, or cause transdifferentiation as defined by expression of Sertoli markers. Since we do not find defects in the ovarian somatic program, the subsequent failure to form follicles at perinatal stages is likely attributable to the absence of germ cells rather than to defects in the somatic cells. PMID:23091613

Maatouk, Danielle M; Mork, Lindsey; Hinson, Ashley; Kobayashi, Akio; McMahon, Andrew P; Capel, Blanche

2012-01-01

288

Growth Transformation of Human T Cells by Herpesvirus Saimiri Requires Multiple Tip-Lck Interaction Motifs  

PubMed Central

Lymphoma induction and T-cell transformation by herpesvirus saimiri strain C488 depends on two viral oncoproteins, StpC and Tip. The major interaction partner of Tip is the protein tyrosine kinase Lck, a key regulator of T-cell activation. The Lck binding domain (LBD) of Tip comprises two interaction motifs, a proline-rich SH3 domain-binding sequence (SH3B) and a region with homology to the C terminus of Src family kinase domains (CSKH). In addition, biophysical binding analyses with purified Lck-SH2 domain suggest the phosphorylated tyrosine residue 127 of Tip (pY127) as a potential third Lck interaction site. Here, we addressed the relevance of the individual binding motifs, SH3B, CSKH, and pY127, for Tip-Lck interaction and for human T-cell transformation. Both motifs within the LBD displayed Lck binding activities and cooperated to achieve a highly efficient interaction, while pY127, the major tyrosine phosphorylation site of Tip, did not enhance Lck binding in T cells. Herpesvirus saimiri strain C488 recombinants lacking one or both LBD motifs of Tip lost their transforming potential on human cord blood lymphocytes. Recombinant virus expressing Tip with a mutation at position Y127 was still able to transform human T lymphocytes but, in contrast to wild-type virus, was strictly dependent on exogenous interleukin-2. Thus, the strong Lck binding mediated by cooperation of both LBD motifs was essential for the transformation of human T cells by herpesvirus saimiri C488. The major tyrosine phosphorylation site Y127 of Tip was particularly required for transformation in the absence of exogenous interleukin-2, suggesting its involvement in cytokine signaling pathways. PMID:17005671

Heck, Elke; Friedrich, Ute; Gack, Michaela U.; Lengenfelder, Doris; Schmidt, Monika; Müller-Fleckenstein, Ingrid; Fleckenstein, Bernhard; Ensser, Armin; Biesinger, Brigitte

2006-01-01

289

Growth transformation of human T cells by herpesvirus saimiri requires multiple Tip-Lck interaction motifs.  

PubMed

Lymphoma induction and T-cell transformation by herpesvirus saimiri strain C488 depends on two viral oncoproteins, StpC and Tip. The major interaction partner of Tip is the protein tyrosine kinase Lck, a key regulator of T-cell activation. The Lck binding domain (LBD) of Tip comprises two interaction motifs, a proline-rich SH3 domain-binding sequence (SH3B) and a region with homology to the C terminus of Src family kinase domains (CSKH). In addition, biophysical binding analyses with purified Lck-SH2 domain suggest the phosphorylated tyrosine residue 127 of Tip (pY127) as a potential third Lck interaction site. Here, we addressed the relevance of the individual binding motifs, SH3B, CSKH, and pY127, for Tip-Lck interaction and for human T-cell transformation. Both motifs within the LBD displayed Lck binding activities and cooperated to achieve a highly efficient interaction, while pY127, the major tyrosine phosphorylation site of Tip, did not enhance Lck binding in T cells. Herpesvirus saimiri strain C488 recombinants lacking one or both LBD motifs of Tip lost their transforming potential on human cord blood lymphocytes. Recombinant virus expressing Tip with a mutation at position Y127 was still able to transform human T lymphocytes but, in contrast to wild-type virus, was strictly dependent on exogenous interleukin-2. Thus, the strong Lck binding mediated by cooperation of both LBD motifs was essential for the transformation of human T cells by herpesvirus saimiri C488. The major tyrosine phosphorylation site Y127 of Tip was particularly required for transformation in the absence of exogenous interleukin-2, suggesting its involvement in cytokine signaling pathways. PMID:17005671

Heck, Elke; Friedrich, Ute; Gack, Michaela U; Lengenfelder, Doris; Schmidt, Monika; Müller-Fleckenstein, Ingrid; Fleckenstein, Bernhard; Ensser, Armin; Biesinger, Brigitte

2006-10-01

290

Gossypol induces apoptosis in multiple myeloma cells by inhibition of interleukin-6 signaling and Bcl-2/Mcl-1 pathway  

PubMed Central

Multiple myeloma (MM) is a clonal plasma cell disorder affecting the immune system with various systemic symptoms. MM remains incurable even with high dose chemotherapy using conventional drugs, thus necessitating development of novel therapeutic strategies. Gossypol (Gos) is a natural polyphenolic compound extracted from cotton plants, and has been shown to possess anti-neoplastic activity against various tumors. Recent studies have shown that Gos is an inhibitor for Bcl-2 or Bcl-XL acting as BH3 mimetics that interfere interaction between pro-apoptotic BH3-only proteins and Bcl-2/Bcl-XL. Since most of the patients with MM overexpress Bcl-2 protein, we considered Gos might be a promising therapeutic agent for MM. We herein show that Gos efficiently induced apoptosis and inhibited proliferation of the OPM2 MM cell line, in a dose- and time-dependent manner. Gos induced activation of caspase-3 and cytochrome c release from mitochondria, showing mitochondrial dysfunction pathway is operational during apoptosis. Further investigation revealed that phosphorylation of Bcl-2 at serine-70 was attenuated by Gos treatment, while protein levels were not affected. In addition, Mcl-1 was downregulated by Gos. Interestingly, phosphorylation of JAK2, STAT3, ERK1/2 and p38MAPK was inhibited by Gos-treatment, indicating that Gos globally suppressed interleukin-6 (IL-6) signals. Moreover, JAK2 inhibition mimicked the effect of Gos in OPM2 cells including Bcl-2 dephosphorylation and Mcl-1 downregulation. These results demonstrated that Gos induces apoptosis in MM cells not only through displacing BH3-only proteins from Bcl-2, but also through inhibiting IL-6 signaling, which leads to Bcl-2 dephosphorylation and Mcl-1 downregulation. PMID:25231749

SADAHIRA, KEN; SAGAWA, MORIHIKO; NAKAZATO, TOMONORI; UCHIDA, HIDEO; IKEDA, YASUO; OKAMOTO, SHINICHIRO; NAKAJIMA, HIDEAKI; KIZAKI, MASAHIRO

2014-01-01

291

The Ess1 prolyl isomerase is required for transcription termination of small noncoding RNAs via the Nrd1 pathway.  

PubMed

Genome-wide studies have identified abundant small, noncoding RNAs, including small nuclear RNAs, small nucleolar RNAs (snoRNAs), cryptic unstable transcripts (CUTs), and upstream regulatory RNAs (uRNAs), that are transcribed by RNA polymerase II (pol II) and terminated by an Nrd1-dependent pathway. Here, we show that the prolyl isomerase Ess1 is required for Nrd1-dependent termination of noncoding RNAs. Ess1 binds the carboxy-terminal domain (CTD) of pol II and is thought to regulate transcription by conformational isomerization of Ser-Pro bonds within the CTD. In ess1 mutants, expression of approximately 10% of the genome was altered, due primarily to defects in termination of snoRNAs, CUTs, stable unannotated transcripts, and uRNAs. Ess1 promoted dephosphorylation of Ser5 (but not Ser2) within the CTD, most likely by the Ssu72 phosphatase. We also provide evidence for a competition between Nrd1 and Pcf11 for CTD binding that is regulated by Ess1. These data indicate that a prolyl isomerase is required for specifying the "CTD code." PMID:19854134

Singh, Navjot; Ma, Zhuo; Gemmill, Trent; Wu, Xiaoyun; Defiglio, Holland; Rossettini, Anne; Rabeler, Christina; Beane, Olivia; Morse, Randall H; Palumbo, Michael J; Hanes, Steven D

2009-10-23

292

Pseudomonas fluorescens: Fur is required for multiple biological properties associated with pathogenesis.  

PubMed

Pseudomonas fluorescens, a Gram-negative bacterium, is an aquaculture pathogen with a broad host range. In a previous study, we had demonstrated that knockout of the fur gene of a pathogenic P. fluorescens strain, TSS, resulted in profound virulence attenuation. In this work, we studied the properties of the fur knockout mutant, TFM, in comparison with the wild type strain TSS. We found that compared to TSS, TFM (i) was impaired in siderophore production and extracellular enzyme activities, (ii) exhibited altered global polarity, (iii) was dramatically reduced in the ability to resist oxidative stress, (iv) showed higher tolerance to manganese, and (v) exhibited significantly reduced cytotoxicity. When incubated with cultured host cells, TFM displayed a cellular binding index much lower than that of TSS. Neither TFM nor TSS was able to survive and replicate in host cells. Following inoculation into Japanese flounder (Paralichthys olivaceus), TSS upregulated the expression of a wide range of genes involved in innate immunity, notably IL-1? and two CC chemokines. In contrast, TFM caused significant inductions of only a few genes and to much lower magnitudes than TSS. Given the strong inductions of IL-1? and the two chemokines by TSS, the effect of these three genes on P. fluorescens invasion was examined. The results showed that overexpression of these genes in flounder significantly inhibited TSS dissemination into and colonization of host tissues. Taken together, these results indicate that Fur is required for multiple processes associated with virulence, and that proinflammatory cytokines and chemokines likely play important roles in the clearance of P. fluorescens infection. PMID:25465175

Zhou, Ze-Jun; Zhang, Lu; Sun, Li

2015-01-30

293

Multiple WASP-interacting Protein Recognition Motifs Are Required for a Functional Interaction with N-WASP*  

E-print Network

Multiple WASP-interacting Protein Recognition Motifs Are Required for a Functional Interaction with N-WASP* Received for publication,October 23, 2006, and in revised form, December 27, 2006 Published Research UK, London Research Institute, 44 Lincoln's Inn Fields, London WC2A 3PX, United Kingdom The WASP

Prehoda, Ken

294

Seeking unique and common biological themes in multiple gene lists or datasets: pathway pattern extraction pipeline for pathway-level comparative analysis  

Microsoft Academic Search

Background: One of the challenges in the analysis of microarray data is to integrate and compare the selected (e.g., differential) gene lists from multiple experiments for common or unique underlying biological themes. A common way to approach this problem is to extract common genes from these gene lists and then subject these genes to enrichment analysis to reveal the underlying

Ming Yi; Uma Mudunuri; Anney Che; Robert M. Stephens

2009-01-01

295

Pituitary adenylate cyclase-activating polypeptide (PACAP) inhibits the slow afterhyperpolarizing current sIAHP in CA1 pyramidal neurons by activating multiple signaling pathways.  

PubMed

The slow afterhyperpolarizing current (sIAHP ) is a calcium-dependent potassium current that underlies the late phase of spike frequency adaptation in hippocampal and neocortical neurons. sIAHP is a well-known target of modulation by several neurotransmitters acting via the cyclic AMP (cAMP) and protein kinase A (PKA)-dependent pathway. The neuropeptide pituitary adenylate cyclase activating peptide (PACAP) and its receptors are present in the hippocampal formation. In this study we have investigated the effect of PACAP on the sIAHP and the signal transduction pathway used to modulate intrinsic excitability of hippocampal pyramidal neurons. We show that PACAP inhibits the sIAHP , resulting in a decrease of spike frequency adaptation, in rat CA1 pyramidal cells. The suppression of sIAHP by PACAP is mediated by PAC1 and VPAC1 receptors. Inhibition of PKA reduced the effect of PACAP on sIAHP, suggesting that PACAP exerts part of its inhibitory effect on sIAHP by increasing cAMP and activating PKA. The suppression of sIAHP by PACAP was also strongly hindered by the inhibition of p38 MAP kinase (p38 MAPK). Concomitant inhibition of PKA and p38 MAPK indicates that these two kinases act in a sequential manner in the same pathway leading to the suppression of sIAHP. Conversely, protein kinase C is not part of the signal transduction pathway used by PACAP to inhibit sIAHP in CA1 neurons. Our results show that PACAP enhances the excitability of CA1 pyramidal neurons by inhibiting the sIAHP through the activation of multiple signaling pathways, most prominently cAMP/PKA and p38 MAPK. Our findings disclose a novel modulatory action of p38 MAPK on intrinsic excitability and the sIAHP, underscoring the role of this current as a neuromodulatory hub regulated by multiple protein kinases in cortical neurons. PMID:23996525

Taylor, Ruth D T; Madsen, Marita Grønning; Krause, Michael; Sampedro-Castañeda, Marisol; Stocker, Martin; Pedarzani, Paola

2014-01-01

296

Lipopolysaccharide-induced activation of NF-{kappa}B non-canonical pathway requires BCL10 serine 138 and NIK phosphorylations  

SciTech Connect

Background and aims: B-cell lymphoma/leukemia (BCL)-10 and reactive oxygen species mediate two pathways of NF-{kappa}B (RelA) activation by lipopolysaccharide (LPS) in human colonic epithelial cells. The pathway for LPS activation of RelB by the non-canonical pathway (RelB) in non-myeloid cells was not yet reported, but important for understanding the range of potential microbial LPS-induced effects in inflammatory bowel disease. Methods: Experiments were performed in human colonic epithelial cells and in mouse embryonic fibroblasts deficient in components of the IkappaB kinase (IKK) signalosome, in order to detect mediators of the non-canonical pathway of NF-{kappa}B activation, including nuclear RelB and p52 and phospho- and total NF-{kappa}B inducing kinase (NIK). BCL10 was silenced by siRNA and effects of mutations of specific phosphorylation sites of BCL10 (Ser138Gly and Ser218Gly) were determined. Results: By the non-canonical pathway, LPS exposure increased nuclear RelB and p52, and phospho-NIK, with no change in total NIK. Phosphorylation of BCL10 serine 138 was required for NIK phosphorylation, since mutation of this residue eliminated the increases in phospho-NIK and nuclear RelB and p52. Mutations of either serine 138 or serine 218 reduced RelA, p50, and phospho-I{kappa}B{alpha} of the canonical pathway. Effects of LPS stimulation and BCL10 silencing on NIK phosphorylation were demonstrated in confocal images. Conclusions: LPS induces activation of both canonical and non-canonical pathways of NF-{kappa}B in human colonic epithelial cells, and the non-canonical pathway requires phosphorylations of BCL10 (serine 138) and NIK. These findings demonstrate the important role of BCL10 in mediating LPS-induced inflammation in human colonic epithelial cells and may open new avenues for therapeutic interventions.

Bhattacharyya, Sumit; Borthakur, Alip; Dudeja, Pradeep K. [Department of Medicine, University of Illinois at Chicago and Jesse Brown VA Medical Center, Chicago, IL 60612-7227 (United States)] [Department of Medicine, University of Illinois at Chicago and Jesse Brown VA Medical Center, Chicago, IL 60612-7227 (United States); Tobacman, Joanne K., E-mail: jkt@uic.edu [Department of Medicine, University of Illinois at Chicago and Jesse Brown VA Medical Center, Chicago, IL 60612-7227 (United States)

2010-11-15

297

Coexpression of multiple genes reconstitutes two pathways of very long-chain polyunsaturated fatty acid biosynthesis in Pichia pastoris.  

PubMed

The introduction of novel traits to cells often requires the stable coexpression of multiple genes within the same cell. Herein, we report that C22 very long-chain polyunsaturated fatty acids (VLC-PUFAs) were synthesized from C18 precursors by reactions catalyzed by delta 6-desaturase, an ELOVL5 involved in VLC-PUFA elongation, and delta 5-desaturase. The coexpression of McD6DES, AsELOVL5, and PtD5DES encoding the corresponding enzymes, produced docosatetraenoic acid (C22:4 n-6) and docosapentaenoic acid (C22:5 n-3), as well as arachidonic acid (C20:4 n-6) and eicosapentaenoic acid (C20:5 n-3) in the methylotrophic yeast Pichia pastoris. The expression of each gene increased within 24 h, with high transcript levels after induction with 0.5 or 1 % methanol. High levels of the newly expressed VLC-PUFAs occurred after 144 h. This expression system exemplifies the recent progress and future possibilities of the metabolic engineering of VLC-PUFAs in oilseed crops. PMID:24863294

Kim, Sun Hee; Roh, Kyung Hee; Kim, Kwang-Soo; Kim, Hyun Uk; Lee, Kyeong-Ryeol; Kang, Han-Chul; Kim, Jong-Bum

2014-09-01

298

The transcription factor E4BP4 is not required for extramedullary pathways of NK cell development.  

PubMed

NK cells contribute to antitumor and antiviral immunosurveillance. Their development in the bone marrow (BM) requires the transcription factor E4BP4/NFIL3, but requirements in other organs are less well defined. In this study, we show that CD3(-)NK1.1(+)NKp46(+)CD122(+) NK cells of immature phenotype and expressing low eomesodermin levels are found in thymus, spleen, and liver of E4BP4-deficient mice, whereas numbers of mature, eomesodermin(high) conventional NK cells are drastically reduced. E4BP4-deficient CD44(+)CD25(-) double-negative 1 thymocytes efficiently develop in vitro into NK cells with kinetics, phenotype, and functionality similar to wild-type controls, whereas no NK cells develop from E4BP4-deficient BM precursors. In E4BP4/Rag-1 double-deficient (DKO) mice, NK cells resembling those in Rag-1-deficient controls are found in similar numbers in the thymus and liver. However, NK precursors are reduced in DKO BM, and no NK cells develop from DKO BM progenitors in vitro. DKO thymocyte precursors readily develop into NK cells, but DKO BM transfers into nude recipients and NK cells in E4BP4/Rag-1/IL-7 triple-KO mice indicated thymus-independent NK cell development. In the presence of T cells or E4BP4-sufficient NK cells, DKO NK cells have a selective disadvantage, and thymic and hepatic DKO NK cells show reduced survival when adoptively transferred into lymphopenic hosts. This correlates with higher apoptosis rates and lower responsiveness to IL-15 in vitro. In conclusion, we demonstrate E4BP4-independent development of NK cells of immature phenotype, reduced fitness, short t1/2, and potential extramedullary origin. Our data identify E4BP4-independent NK cell developmental pathways and a role for E4BP4 in NK cell homeostasis. PMID:24534532

Crotta, Stefania; Gkioka, Annita; Male, Victoria; Duarte, João H; Davidson, Sophia; Nisoli, Ilaria; Brady, Hugh J M; Wack, Andreas

2014-03-15

299

Gene Expression Profile Reveals Abnormalities of Multiple Signaling Pathways in Mesenchymal Stem Cell Derived from Patients with Systemic Lupus Erythematosus  

PubMed Central

We aimed to compare bone-marrow-derived mesenchymal stem cells (BMMSCs) between systemic lupus erythematosus (SLE) and normal controls by means of cDNA microarray, immunohistochemistry, immunofluorescence, and immunoblotting. Our results showed there were a total of 1, 905 genes which were differentially expressed by BMMSCs derived from SLE patients, of which, 652 genes were upregulated and 1, 253 were downregulated. Gene ontology (GO) analysis showed that the majority of these genes were related to cell cycle and protein binding. Pathway analysis exhibited that differentially regulated signal pathways involved actin cytoskeleton, focal adhesion, tight junction, and TGF-? pathway. The high protein level of BMP-5 and low expression of Id-1 indicated that there might be dysregulation in BMP/TGF-? signaling pathway. The expression of Id-1 in SLE BMMSCs was reversely correlated with serum TNF-? levels. The protein level of cyclin E decreased in the cell cycling regulation pathway. Moreover, the MAPK signaling pathway was activated in BMMSCs from SLE patients via phosphorylation of ERK1/2 and SAPK/JNK. The actin distribution pattern of BMMSCs from SLE patients was also found disordered. Our results suggested that there were distinguished differences of BMMSCs between SLE patients and normal controls. PMID:22966240

Tang, Yu; Ma, Xiaolei; Zhang, Huayong; Gu, Zhifeng; Hou, Yayi; Gilkeson, Gary S.; Lu, Liwei; Zeng, Xiaofeng; Sun, Lingyun

2012-01-01

300

Multiple IMU system test plan, volume 4. [subroutines for space shuttle requirements  

NASA Technical Reports Server (NTRS)

Operating procedures for this redundant system are described. A test plan is developed with two objectives. First, performance of the hardware and software delivered is demonstrated. Second, applicability of multiple IMU systems to the space shuttle mission is shown through detailed experiments with FDI algorithms and other multiple IMU software: gyrocompassing, calibration, and navigation. Gimbal flip is examined in light of its possible detrimental effects on FDI and navigation. For Vol. 3, see N74-10296.

Landey, M.; Vincent, K. T., Jr.; Whittredge, R. S.

1974-01-01

301

Membrane Recruitment of Aut7p in the Autophagy and Cytoplasm to Vacuole Targeting Pathways Requires Aut1p, Aut2p, and the Autophagy Conjugation Complex  

Microsoft Academic Search

Autophagy is a degradative pathway by which cells sequester nonessential, bulk cytosol into double-membrane vesicles (autophagosomes) and de- liver them to the vacuole for recycling. Using this strategy, eukaryotic cells survive periods of nutritional starvation. Under nutrient-rich conditions, autophagy machinery is required for the delivery of a resident vac- uolar hydrolase, aminopeptidase I, by the cytoplasm to vacuole targeting (Cvt)

John Kim; Wei-Pang Huang; Daniel J. Klionsky

2001-01-01

302

Proteomic-based identification of multiple pathways underlying n-butylidenephthalide-induced apoptosis in LNCaP human prostate cancer cells.  

PubMed

Although numerous studies have shown the cancer-preventive properties of butylidenephthalide (BP), there is little report of BP affecting human prostate cancer cells. In the present study, proteomic-based approaches were used to elucidate the anticancer mechanism of BP in LNCaP human prostate cancer cells. BP treatment decreased the viability of LNCaP human prostate cancer cells in a concentration- and time-dependent manner, which was correlated with G0/G1 phase cell cycle arrest. Increased cell cycle arrest was associated with a decrease in the level of CCND1, CDK2, and PCNA proteins and an increase in the level of CDKN2A, CDKN1A, and SFN proteins. Proteomic studies revealed that among 48 differentially expressed proteins, 25 proteins were down-regulated and 23 proteins were up-regulated and these proteins fall into one large protein protein interaction network. Among these proteins, FAS, AIFM1, BIK, CYCS, SFN, PPP2R1A, CALR, HSPA5, DDIT3, and ERN1 are apoptosis and endoplasmic reticulum (ER) stress associated proteins. Proteomic data suggested that multiple signaling pathways including FAS-dependent pathway, mitochondrial pathway, and ER stress pathway are involved in the apoptosis induced by BP. PMID:23770345

Pang, Cheng-Yoong; Chiu, Sheng-Chun; Harn, Horng-Jyh; Zhai, Wei-Jun; Lin, Shinn-Zong; Yang, Hsueh-Hui

2013-09-01

303

Renal Protective Role of Xiexin Decoction with Multiple Active Ingredients Involves Inhibition of Inflammation through Downregulation of the Nuclear Factor-?B Pathway in Diabetic Rats  

PubMed Central

In Chinese medicine, Xiexin decoction (XXD) has been used for the clinical treatment of diabetes for at least 1700 years. The present study was conducted to investigate the effective ingredients of XXD and their molecular mechanisms of antidiabetic nephropathy in rats. Rats with diabetes induced by high-fat diet and streptozotocin were treated with XXD extract for 12 weeks. XXD significantly improved the glucolipid metabolism disorder, attenuated albuminuria and renal pathological changes, reduced renal advanced glycation end-products, inhibited receptor for advanced glycation end-product and inflammation factors expression, suppressed renal nuclear factor-?B pathway activity, and downregulated renal transforming growth factor-?1. The concentrations of multiple components in plasma from XXD were determined by liquid chromatography and tandem mass spectrometry. Pharmacokinetic/pharmacodynamic analysis using partial least square regression revealed that 8 ingredients of XXD were responsible for renal protective effects via actions on multiple molecular targets. Our study suggests that the renal protective role of XXD with multiple effective ingredients involves inhibition of inflammation through downregulation of the nuclear factor-?B pathway, reducing renal advanced glycation end-products and receptor for advanced glycation end-product in diabetic rats. PMID:23935673

Wu, Jia-sheng; Shi, Rong; Zhong, Jie; Lu, Xiong; Ma, Bing-liang; Wang, Tian-ming; Zan, Bin; Ma, Yue-ming; Cheng, Neng-neng; Qiu, Fu-rong

2013-01-01

304

Cervical aortic arch with multiple aortic aneurysms that required two aortic replacements with a 34-year interval.  

PubMed

A 57-year old female was referred to our hospital after symptoms of hoarseness and dysphagia for a few years. She was diagnosed with a cervical vessel anomaly during childhood and had undergone surgery for a right-sided thoracic descending aortic aneurysm through a right thoracotomy at the age of 23 years. Now, enhanced computed tomography revealed newly developed multiple aneurysms in the aorta between the left carotid artery and the proximal descending aorta in the left hemithorax. A successful aortic surgical repair was accomplished via a left posterolateral thoracotomy. To our knowledge, this is the first case of a cervical aortic arch with formation of multiple aneurysms that required multiple surgeries via bilateral thoracotomies. This case suggests the inherent fragility and possibility of later aneurysmal formation in malformed vessels, thereby emphasizing the importance of periodical imaging tests in this rare congenital anomaly. PMID:25100228

Ito, Hideki; Abe, Tomonobu; Oshima, Hideki; Usui, Akihiko

2014-11-01

305

Growth factor requirements for the stimulation of germinal center B cells: evidence for an IL-2-dependent pathway of development.  

PubMed

Germinal center (GC) B cells readily undergo apoptosis, a tendency which can be suppressed in vitro by immobilized anti-Ig; mAb to CD40 and soluble CD23 (in synergy with IL-1 alpha) also effect rescue of GC cells from programmed cell death. In the present study, the signals which stimulate rescued GC populations to DNA synthesis have been examined and compared to those established for the activation of follicular mantle (FM) B cells. On co-culture with anti-Ig, optimal responses in FM B cells can be achieved with a combination of IL-4 and CD40 antibody; these activities also provided a modest stimulus to GC cells but, for this population, anti-Ig was ineffective at augmenting the response further. Stimulations of GC B cells were enhanced, however, when performed on a support of primary fetal lung fibroblasts; a major influence of stroma was to promote, by direct cell-cell contact, the CD40-dependent survival of GC B cells. FM B cells were relatively independent of such stromal support. In marked contrast to FM cells, GC B cells were found to respond by enhanced DNA synthesis to IL-2 even when quite low concentrations of the factor were present (IC50 = 2 U/ml). Stimulation of GC cells via this pathway was augmented almost 2-fold on the inclusion of anti-Ig whereas neither fibroblasts, IL-4, nor CD40 antibody made any additional contribution to the IL-2-dependent response. The requirements found for stimulating GC cells in vitro are discussed with reference to the signals that this population may encounter in appropriate microenvironments in vivo: the variety of options apparently available could reflect changing priorities at different stages of a developing GC response. PMID:1723294

Holder, M J; Liu, Y J; Defrance, T; Flores-Romo, L; MacLennan, I C; Gordon, J

1991-12-01

306

78 FR 13781 - Filings Required of Multiple Employer Welfare Arrangements and Certain Other Related Entities  

Federal Register 2010, 2011, 2012, 2013

...or businesses under common control. The determination of whether...business is under ``common control'' with another trade or business...of this paragraph, common control shall not be based on an interest...by section 302(b) of the Multiple Employer Welfare...

2013-03-01

307

Male alternative reproductive behaviours in a Mediterranean wrasse, Symphodus ocellatus: Evidence from otoliths for multiple life-history pathways  

Microsoft Academic Search

Although alternative reproductive behaviours have been studied extensively, it has only been possible in a few cases to document the underlying life-history pathways and factors that determine their expression. In Symphodus ocellatus, a Mediterranean wrasse, males adopt a variety of behaviours. Within a season, they may invest in territory defence, nest building and broodcare (nesting males); join nesting males in

Suzanne H. Alonzo; Michael Taborsky; Peter Wirtz

308

49 CFR 234.306 - Multiple dispatching or maintaining railroads with respect to the same highway-rail or pathway...  

Code of Federal Regulations, 2013 CFR

... Multiple dispatching or maintaining railroads with respect to the same highway-rail...crossing; appointment of responsible railroad. 234.306 Section 234.306 Transportation...Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF...

2013-10-01

309

49 CFR 234.306 - Multiple dispatching or maintaining railroads with respect to the same highway-rail or pathway...  

Code of Federal Regulations, 2012 CFR

... Multiple dispatching or maintaining railroads with respect to the same highway-rail...crossing; appointment of responsible railroad. 234.306 Section 234.306 Transportation...Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF...

2012-10-01

310

Decursin and Doxorubicin Are in Synergy for the Induction of Apoptosis via STAT3 and/or mTOR Pathways in Human Multiple Myeloma Cells  

PubMed Central

Background. Combination cancer therapy is one of the attractive approaches to overcome drug resistance of cancer cells. In the present study, we investigated the synergistic effect of decursin from Angelica gigas and doxorubicin on the induction of apoptosis in three human multiple myeloma cells. Methodology/Principal Findings. Combined treatment of decursin and doxorubicin significantly exerted significant cytotoxicity compared to doxorubicin or decursin in U266, RPMI8226, and MM.1S cells. Furthermore, the combination treatment enhanced the activation of caspase-9 and -3, the cleavage of PARP, and the sub G1 population compared to either drug alone in three multiple myeloma cells. In addition, the combined treatment downregulated the phosphorylation of mTOR and its downstream S6K1 and activated the phosphorylation of ERK in three multiple myeloma cells. Furthermore, the combined treatment reduced mitochondrial membrane potential, suppressed the phosphorylation of JAK2, STAT3, and Src, activated SHP-2, and attenuated the expression of cyclind-D1 and survivin in U266 cells. Conversely, tyrosine phosphatase inhibitor pervanadate reversed STAT3 inactivation and also PARP cleavage and caspase-3 activation induced by combined treatment of doxorubicin and decursin in U266 cells. Conclusions/Significance. Overall, the combination treatment of decursin and doxorubicin can enhance apoptotic activity via mTOR and/or STAT3 signaling pathway in multiple myeloma cells. PMID:23818927

Jang, Jinsil; Jeong, Soo-Jin; Kwon, Hee-Young; Jung, Ji Hoon; Sohn, Eun Jung; Lee, Hyo-Jung; Kim, Ji-Hyun; Kim, Sun-Hee; Kim, Jin Hyoung; Kim, Sung-Hoon

2013-01-01

311

Transcription factor-pathway co-expression analysis reveals cooperation between SP1 and ESR1 on dysregulating cell cycle arrest in non-hyperdiploid multiple myeloma  

PubMed Central

Multiple myeloma is a hematological cancer of plasma B-cells and remains incurable. Two major subtypes of myeloma, hyperdiploid (HMM) and non-hyperdiploid myeloma (NHMM), have distinct chromosomal alterations and different survival outcomes. Transcription factors (TrFs) have been implicated in myeloma oncogenesis but their dysregulation in myeloma subtypes are less studied. Here we develop a TrF-pathway co-expression analysis to identify altered co-expression between two sample types. We apply the method to the two myeloma subtypes and the cell cycle arrest pathway, which is significantly differentially expressed between the two subtypes. We find that TrFs MYC, NF-?B and HOXA9 have significantly lower co-expression with cell cycle arrest in HMM, co-occurring with their over-activation in HMM. In contrast, TrFs ESR1, SP1 and E2F1 have significantly lower co-expression with cell cycle arrest in NHMM. SP1 ChIP targets are enriched by cell cycle arrest genes. These results motivate a cooperation model of ESR1 and SP1 in regulating cell cycle arrest, and a hypothesis that their over-activation in NHMM disrupts proper regulation of cell cycle arrest. Co-targeting ESR1 and SP1 shows a synergistic effect on inhibiting myeloma proliferation in NHMM cell lines. Therefore, studying TrF-pathway co-expression dysregulation in human cancers facilitates forming novel hypotheses towards clinical utility. PMID:23925045

Wang, Xujun; Yan, Zhenyu; Fulciniti, Mariateresa; Li, Yingxiang; Gkotzamanidou, Maria; Amin, Samir B; Shah, Parantu K; Zhang, Yong

2014-01-01

312

Enhancement of HCO3 Permeability across the Apical Membrane of Bovine Corneal Endothelium by Multiple Signaling Pathways  

Microsoft Academic Search

PURPOSE. In this study, the involvement of signaling pathways in the regulation of HCO3 permeability across the apical membrane of the corneal endothelium was examined. METHODS. Cultured bovine corneal endothelial cells (CBCECs) were grown to confluence on permeable membranes. Apical and basolateral sides were perfused with a HCO3 -rich Cl- free Ringer's solution (28.5 mM; pH 7.5). Relative changes in

Yan Zhang; Qiang Xie; Xing Cai Sun; Joseph A. Bonanno

313

Source-pathway separation of multiple contaminants during a rainfall-runoff event in an artificially drained agricultural watershed.  

PubMed

A watershed's water quality is influenced by contaminant-transport pathways unique to each landscape. Accurate information on contaminant-pathways could provide a basis for mitigation through well-targeted approaches. This study determined dynamics of nitrate-N, total P, Escherichia coli, and sediment during a runoff event in Tipton Creek, Iowa. The watershed, under crop and livestock production, has extensive tile drainage discharging through an alluvial valley. A September 2006 storm yielded 5.9 mm of discharge during the ensuing 7 d, which was monitored at the outlet (19,850 ha), two tile-drainage outfalls (total 1856 ha), and a runoff flume (11 ha) within the sloped valley. Hydrograph separations indicated 13% of tile discharge was from surface intakes. Tile and outlet nitrate-N loads were similar, verifying subsurface tiles dominate nitrate delivery. On a unit-area basis, tile total P and E. coli loads, respectively, were about half and 30% of the outlet's; their rapid, synchronous timing showed surface intakes are an important pathway for both contaminants. Flume results indicated field runoff was a significant source of total P and E. coli loads, but not the dominant one. At the outlet, sediment, P, and E. coli were reasonably synchronous. Radionuclide activities of (7)Be and (210)Pb in suspended sediments showed sheet-and-rill erosion sourced only 22% of sediment contributions; therefore, channel sources dominated and were an important source of P and E. coli. The contaminants followed unique pathways, necessitating separate mitigation strategies. To comprehensively address water quality, erosion-control and nitrogen-management practices currently encouraged could be complemented by buffering surface intakes and stabilizing stream banks. PMID:20400584

Tomer, M D; Wilson, C G; Moorman, T B; Cole, K J; Heer, D; Isenhart, T M

2010-01-01

314

Clonal Evolution in t(14;18)Positive Follicular Lymphoma, Evidence for Multiple Common Pathways, and Frequent Parallel Clonal Evolution  

Microsoft Academic Search

Purpose: Follicular lymphoma typically has acquired a t(14;18) translocation, but subsequent additional cytogenetic abnormalities contribute to disease progression. The main aims of the study are to (a) identify the frequency and temporal sequence of cytogenetic events in t(14;18)-positive follicular lymphoma, (b) determine if there are specific pathways in the evolution of follicular lymphoma, (c) determine the clonal divergence in cases

Francesco d'Amore; Eric Chan; Javeed Iqbal; Huimin Geng; Li Xiao; Michelle M. Hess; Warren G. Sanger; Lynette Smith; Carsten Wiuf; Oskar Hagberg; Kai Fu; Wing C. Chan; Bhavana J. Dave

2008-01-01

315

Isoprenoid pathway activity is required for IgE receptor-mediated, tyrosine kinase-coupled transmembrane signaling in permeabilized RBL-2H3 rat basophilic leukemia cells.  

PubMed Central

Previously, we reported that the isoprenoid pathway inhibitor, lovastatin, blocks the activation by IgE receptor cross-linking of 45Ca2+ influx, 1,4,5-inositol trisphosphate production, secretion, and membrane changes (ruffling, spreading) in intact RBL-2H3 rat basophilic leukemia cells. These results indicated that an isoprenoid pathway intermediate, very likely an isoprenylated protein, is importantly involved in the control of IgE receptor-mediated signal transduction. Here, we show that 20 h of pretreatment with lovastatin also inhibits antigen-induced secretion and membrane responses in streptolysin O-(SLO)-permeabilized cells. However, lovastatin does not inhibit secretion stimulated by the nonhydrolyzable GTP analog, GTP gamma S. Furthermore, the membrane responses to GTP gamma S persist, although in an attenuated form, in lovastatin-treated permeabilized cells. The relative insensitivity of GTP gamma S-induced responses to lovastatin was one of several indications that antigen and GTP gamma S may activate separate pathways leading to transmembrane responses in permeabilized cells. Further experiments showed that the beta-thio derivative of GDP, GDPBAS, inhibits the secretory and membrane responses to GTP gamma S, as expected for a GTP-binding protein-dependent signaling pathway, while having little effect on antigen-induced responses. Conversely, genistein blocks the secretory and membrane responses to antigen, as expected for a tyrosine kinase-dependent pathway, without altering the GTP gamma S-induced responses. From these results, and from additional data from cells treated with tyrphostins and sodium orthovanadate, we propose that IgE receptor-mediated secretion from permeabilized RBL-2H3 cells occurs by a tyrosine kinase-dependent pathway that requires isoprenoid pathway activity for function.We propose further that RBL-2H3 cells contain a separate GTP-binding protein-mediated signaling pathway whose direct activation by GTP gamma S is either independent of isoprenoid pathway activity or depends on the activity of an isoprenylated protein that is not significantly depleted after 20 h of lovastatin treatment. Images PMID:1777505

Deanin, G G; Pfeiffer, J R; Cutts, J L; Fore, M L; Oliver, J M

1991-01-01

316

Requirements and potential development pathways for fission energy supply infrastructures of the 21st century - a systems viewpoint.  

SciTech Connect

Using an energy supply systems approach, we envision attributes and characteristic needs of a future global fission-based energy supply infrastructure, enumerate potential pathways for meeting those needs, and identify the underlying enabling science and technology developments for R and D efforts to meet the needs.

Wade, D. C.

1999-06-14

317

The LIM homeobox gene Isl1 is required for the correct development of the striatonigral pathway in the mouse.  

PubMed

The mammalian striatum controls the output of the basal ganglia via two distinct efferent pathways, the direct (i.e., striatonigral) and the indirect (i.e., striatopallidal) pathways. The LIM homeodomain transcription factor Islet1 (Isl1) is expressed in a subpopulation of striatal progenitors; however, its specific role in striatal development remains unknown. Our genetic fate-mapping results show that Isl1-expressing progenitors give rise to striatal neurons belonging to the striatonigral pathway. Conditional inactivation of Isl1 in the telencephalon resulted in a smaller striatum with fewer striatonigral neurons and reduced projections to the substantia nigra. Additionally, conditional inactivation in the ventral forebrain (including both the telencephalon and diencephalon) revealed a unique role for Isl1 in diencephalic cells bordering the internal capsule for the normal development of the striatonigral pathway involving PlexinD1-Semaphorin 3e (Sema3e) signaling. Finally, Isl1 conditional mutants displayed a hyperlocomotion phenotype, and their locomotor response to psychostimulants was significantly blunted, indicating that the alterations in basal ganglia circuitry contribute to these mutant behaviors. PMID:24082127

Ehrman, Lisa A; Mu, Xiuqian; Waclaw, Ronald R; Yoshida, Yutaka; Vorhees, Charles V; Klein, William H; Campbell, Kenneth

2013-10-15

318

Complete reversal of epithelial to mesenchymal transition requires inhibition of both ZEB expression and the Rho pathway  

Microsoft Academic Search

BACKGROUND: Epithelial to Mesenchymal Transition (EMT) induced by Transforming Growth Factor-? (TGF-?) is an important cellular event in organogenesis, cancer, and organ fibrosis. The process to reverse EMT is not well established. Our purpose is to define signaling pathways and transcription factors that maintain the TGF-?-induced mesenchymal state. RESULTS: Inhibitors of five kinases implicated in EMT, TGF-? Type I receptor

Shreyas Das; Bryan N Becker; F Michael Hoffmann; Janet E Mertz

2009-01-01

319

Patterns of somatic mutations in VH genes reveal pathways of clonal transformation from MGUS to multiple myeloma  

Microsoft Academic Search

Monoclonal gammopathy of undeter- mined significance (MGUS) can trans- form to multiple myeloma (MM). In my- eloma, mutated VH genes with sequence homogeneity reveal a postfollicular ori- gin. Previously, some MGUS cases showed mutated VH genes with intra- clonal variation, indicating an earlier stage of arrest. We investigated progression from 2 of 2 MGUS to MM, in which VH genes

Niklas Zojer; Heinz Ludwig; Michael Fiegl; Freda K. Stevenson; Surinder S. Sahota

2003-01-01

320

Policy, Service Pathways and Mortality: A 10-Year Longitudinal Study of People with Profound Intellectual and Multiple Disabilities  

ERIC Educational Resources Information Center

Background: One hundred and forty-two children and adults with profound intellectual and multiple disabilities were identified in 1993 in a single Scottish region on whom detailed information was collected via a postal questionnaire survey. Methods: They were followed up in 2003. The time spanned represented a period of significant policy change…

Hogg, James; Juhlberg, K.; Lambe, L.

2007-01-01

321

Celsr1 is required for the generation of polarity at multiple levels of the mouse oviduct.  

PubMed

The oviduct is an important organ in reproduction where fertilization occurs, and through which the fertilized eggs are carried to the uterus in mammals. This organ is highly polarized, where the epithelium forms longitudinal folds along the ovary-uterus axis, and the epithelial multicilia beat towards the uterus to transport the ovulated ova. Here, we analyzed the postnatal development of mouse oviduct and report that multilevel polarities of the oviduct are regulated by a planar cell polarity (PCP) gene, Celsr1. In the epithelium, Celsr1 is concentrated in the specific cellular boundaries perpendicular to the ovary-uterus axis from postnatal day 2. We found a new feature of cellular polarity in the oviduct - the apical surface of epithelial cells is elongated along the ovary-uterus axis. In Celsr1-deficient mice, the ciliary motion is not orchestrated along the ovary-uterus axis and the transport ability of beating cilia is impaired. Epithelial cells show less elongation and randomized orientation, and epithelial folds show randomized directionality and ectopic branches in the mutant. Our mosaic analysis suggests that the geometry of epithelial cells is primarily regulated by Celsr1 and as a consequence the epithelial folds are aligned. Taken together, we reveal the characteristics of the multilevel polarity formation processes in the mouse oviduct epithelium and suggest a novel function of the PCP pathway for proper tissue morphogenesis. PMID:25406397

Shi, Dongbo; Komatsu, Kouji; Hirao, Mayumi; Toyooka, Yayoi; Koyama, Hiroshi; Tissir, Fadel; Goffinet, André M; Uemura, Tadashi; Fujimori, Toshihiko

2014-12-01

322

Multiple PLDs Required for High Salinity and Water Deficit Tolerance in Plants  

PubMed Central

High salinity and drought have received much attention because they severely affect crop production worldwide. Analysis and comprehension of the plant's response to excessive salt and dehydration will aid in the development of stress-tolerant crop varieties. Signal transduction lies at the basis of the response to these stresses, and numerous signaling pathways have been implicated. Here, we provide further evidence for the involvement of phospholipase D (PLD) in the plant's response to high salinity and dehydration. A tomato (Lycopersicon esculentum) ?-class PLD, LePLD?1, is transcriptionally up-regulated and activated in cell suspension cultures treated with salt. Gene silencing revealed that this PLD is indeed involved in the salt-induced phosphatidic acid production, but not exclusively. Genetically modified tomato plants with reduced LePLD?1 protein levels did not reveal altered salt tolerance. In Arabidopsis (Arabidopsis thaliana), both AtPLD?1 and AtPLD? were found to be activated in response to salt stress. Moreover, pld?1 and pld? single and double knock-out mutants exhibited enhanced sensitivity to high salinity stress in a plate assay. Furthermore, we show that both PLDs are activated upon dehydration and the knock-out mutants are hypersensitive to hyperosmotic stress, displaying strongly reduced growth. PMID:19017627

Bargmann, Bastiaan O. R.; Laxalt, Ana M.; ter Riet, Bas; van Schooten, Bas; Merquiol, Emmanuelle; Testerink, Christa; Haring, Michel A.; Bartels, Dorothea; Munnik, Teun

2009-01-01

323

Evaluating Multiple Indices from a Canopy Reflectance Sensor to Estimate Corn N Requirements  

Technology Transfer Automated Retrieval System (TEKTRAN)

With the increasing cost of fertilizer N, there is a renewed emphasis on developing new technologies for quantifying in-season N requirements for corn. The objectives of this research are (i) to evaluate different vegetative indices derived from an active reflectance sensor in estimating in-season N...

324

Whole gene expression profile in blood reveals multiple pathways deregulation in R6/2 mouse model  

PubMed Central

Background Huntington Disease (HD) is a progressive neurological disorder, with pathological manifestations in brain areas and in periphery caused by the ubiquitous expression of mutant Huntingtin protein. Transcriptional dysregulation is considered a key molecular mechanism responsible of HD pathogenesis but, although numerous studies investigated mRNA alterations in HD, so far none evaluated a whole gene expression profile in blood of R6/2 mouse model. Findings To discover novel pathogenic mechanisms and potential peripheral biomarkers useful to monitor disease progression or drug efficacy, a microarray study was performed in blood of R6/2 at manifest stage and wild type littermate mice. This approach allowed to propose new peripheral molecular processes involved in HD and to suggest different panels of candidate biomarkers. Among the discovered deregulated processes, we focused on specific ones: complement and coagulation cascades, PPAR signaling, cardiac muscle contraction, and dilated cardiomyopathy pathways. Selected genes derived from these pathways were additionally investigated in other accessible tissues to validate these matrices as source of biomarkers, and in brain, to link central and peripheral disease manifestations. Conclusions Our findings validated the skeletal muscle as suitable source to investigate peripheral transcriptional alterations in HD and supported the hypothesis that immunological alteration may contribute to neurological degeneration. Moreover, the identification of altered signaling in mouse blood enforce R6/2 transgenic mouse as a powerful HD model while suggesting novel disease biomarkers for pre-clinical investigation. PMID:24252798

2013-01-01

325

Adenosine is required for sustained inflammasome activation via the A2A receptor and the HIF-1? pathway  

NASA Astrophysics Data System (ADS)

Inflammasome pathways are important in chronic diseases; however, it is not known how the signalling is sustained after initiation. Inflammasome activation is dependent on stimuli such as lipopolysaccharide (LPS) and ATP that provide two distinct signals resulting in rapid production of interleukin (IL)-1?, with the lack of response to repeat stimulation. Here we report that adenosine is a key regulator of inflammasome activity, increasing the duration of the inflammatory response via the A2A receptor. Adenosine does not replace signals provided by stimuli such as LPS or ATP but sustains inflammasome activity via a cAMP/PKA/CREB/HIF-1? pathway. In the setting of the lack of IL-1? responses after previous exposure to LPS, adenosine can supersede this tolerogenic state and drive IL-1? production. These data reveal that inflammasome activity is sustained, after initial activation, by A2A receptor-mediated signalling.

Ouyang, Xinshou; Ghani, Ayaz; Malik, Ahsan; Wilder, Tuere; Colegio, Oscar Rene; Flavell, Richard Anthony; Cronstein, Bruce Neil; Mehal, Wajahat Zafar

2013-12-01

326

The Twin-Arginine Translocation Pathway of Mycobacterium smegmatis Is Functional and Required for the Export of Mycobacterial  -Lactamases  

Microsoft Academic Search

The twin-arginine translocation (Tat) pathway exports folded proteins across the bacterial cytoplasmic membrane and is responsible for the proper extracytoplasmic localization of proteins involved in a variety of cellular functions, including pathogenesis. The Mycobacterium tuberculosis and Mycobacterium smegmatis ge- nomes contain open reading frames with homology to components of the Tat export system (TatABC) as well as potential Tat-exported proteins

Justin A. McDonough; Kari E. Hacker; Anthony R. Flores; Miriam Braunstein

2005-01-01

327

Embolization of a giant arterioportal fistula requiring multiple Amplatzer vascular plugs.  

PubMed

Arterioportal fistulas (APFs) are rare vascular communications between the mesenteric arterial tree and the portal vein. The causes and presentations of this entity are varied. APFs related to tumor, infection, and trauma have been described. Patients may be asymptomatic or present with hemobilia, portal hypertension, or mesenteric steal syndrome. Small APFs require no intervention, with treatment indicated for large or symptomatic APFs. The treatment has shifted from surgical ligation or hepatic resection to an endovascular-first approach. We describe an endovascular treatment option for the management of an acquired extrahepatic (type 2) APF and present a review of the literature. PMID:24840744

Ward, Thomas J; Marin, Michael L; Lookstein, Robert A

2014-05-16

328

ccm2-like is required for cardiovascular development as a novel component of the Heg-CCM pathway  

PubMed Central

The Heart of Glass-Cerebral Cavernous Malformation (Heg-CCM) pathway is essential for normal cardiovascular development in zebrafish and mouse. In zebrafish, the Heg-CCM pathway mutants santa(ccm1/san), valentine (ccm2/vtn), and heart of glass (heg) exhibit severely dilated hearts and inflow tracts and a complete absence of blood circulation. We identified a novel gene based on its sequence identity with ccm2, which we have named ccm2-like (ccm2l), and characterized its role in cardiovascular development. Disruption of ccm2l by morpholino injection causes dilation of the atrium and inflow tract and compromised blood circulation. Morpholino co-injection experiments identify ccm2l as an enhancer of the characteristic Heg-CCM dilated heart phenotype, and we find that ccm2 overexpression can partially rescue ccm2l morphant defects. Finally, we show that Ccm2l binds Ccm1 and perform deletion and mutational analyses to define the regions of Ccm1 that mediate its binding to Ccm2l and its previously established interactors Ccm2 and Heg. These genetic and biochemical data argue that ccm2l is a necessary component of the Heg-CCM pathway. PMID:23328253

Rosen, Jonathan N.; Sogah, Vanessa M.; Ye, Lillian Y.; Mably, John D.

2015-01-01

329

Assessment of groundwater pathways and contaminant transport in Florida and Georgia using multiple chemical and microbiological indicators  

USGS Publications Warehouse

The hydrogeology of Florida, especially in the northern part of the state, and southwestern Georgia is characterized by a predominance of limestone aquifers overlain by varying amounts of sands, silts, and clays. This karstic system of aquifers and their associated springs is particularly vulnerable to contamination from various anthropogenic activities at the land surface. Numerous sinkholes, disappearing streams, and conduit systems or dissolution pathways, often associated with large spring systems, allow rapid movement of contaminants from the land surface to the groundwater system with little or no attenuation or degradation. The fate of contaminants in the groundwater system is not fully understood, but traveltimes from sources are greatly reduced when conduits are intercepted by pumping wells and springs. Contaminant introduction to groundwater systems in Florida and Georgia is not limited to seepage from land surface, but can be associated with passive (drainage wells) and forced subsurface injection (aquifer storage and recovery, waste-water disposal).

Mahon, Gary L.

2011-01-01

330

Feedback Phosphorylation of the Yeast a-Factor Receptor Requires Activation of the Downstream Signaling Pathway from G Protein through Mitogen-Activated Protein Kinase  

PubMed Central

The two yeast pheromone receptors, the a and ?-factor receptors, share many functional similarities: both G protein-coupled receptors couple to the same downstream signal transduction pathway, and both receptors undergo feedback regulation involving increased phosphorylation on their C-terminal domains in response to ligand challenge. The present work, which focuses on the signaling mechanism controlling this feedback phosphorylation, indicates one striking difference. While the ?-factor-induced phosphorylation of the ?-factor receptor does not require activation of the downstream G protein-directed signaling pathway (B. Zanolari, S. Raths, B. Singer-Kruger, and H. Riezman, Cell 71:755–763, 1992), the a-factor-induced phosphorylation of the a-factor receptor (Ste3p) clearly does. Induced Ste3p phosphorylation was blocked in cells with disruptions of various components of the pheromone response pathway, indicating a requirement of pathway components extending from the G protein down through the mitogen-activated protein kinase (MAPK). Furthermore, Ste3p phosphorylation can be induced in the absence of the a-factor ligand when the signaling pathway is artificially activated, indicating that the liganded receptor is not required as a substrate for induced phosphorylation. While the activation of signaling is critical for the feedback phosphorylation of Ste3p, pheromone-induced gene transcription, one of the major outcomes of pheromone signaling, appears not to be required. This conclusion is indicated by three results. First, ste12? cells differ from cells with disruptions of the upstream signaling elements (e.g., ste4?, ste20?, ste5?, ste11?, ste7?, or fus3? kss1? cells) in that they clearly retain some capacity for inducing Ste3p phosphorylation. Second, while activated alleles of STE11 and STE12 induce a strong transcriptional response, they fail to induce a-factor receptor phosphorylation. Third, blocking of new pheromone-induced protein synthesis with cycloheximide fails to block phosphorylation. These findings are discussed within the context of a recently proposed model for pheromone signaling (P. M. Pryciak and F. A. Huntress, Genes Dev. 12:2684–2697, 1998): a key step of this model is the activation of the MAPK Fus3p through the G??-dependent relocalization of the Ste5p-MAPK cascade to the plasma membrane. Ste3p phosphorylation may involve activated MAPK Fus3p feeding back upon plasma membrane targets. PMID:10611235

Feng, Ying; Davis, Nicholas G.

2000-01-01

331

Extended Pausing by Humans on Multiple Fixed-Ratio Schedules with Varied Reinforcer Magnitude and Response Requirements  

PubMed Central

We conducted three experiments to reproduce and extend Perone and Courtney's (1992) study of pausing at the beginning of fixed-ratio schedules. In a multiple schedule with unequal amounts of food across two components, they found that pigeons paused longest in the component associated with the smaller amount of food (the lean component), but only when it was preceded by the rich component. In our studies, adults with mild intellectual disabilities responded on a touch-sensitive computer monitor to produce money. In Experiment 1, the multiple-schedule components differed in both response requirement and reinforcer magnitude (i.e., the rich component required fewer responses and produced more money than the lean component). Effects shown with pigeons were reproduced in all 7 participants. In Experiment 2, we removed the stimuli that signaled the two schedule components, and participants' extended pausing was eliminated. In Experiment 3, to assess sensitivity to reinforcer magnitude versus fixed-ratio size, we presented conditions with equal ratio sizes but disparate magnitudes and conditions with equal magnitudes but disparate ratio sizes. Sensitivity to these manipulations was idiosyncratic. The present experiments obtained schedule control in verbally competent human participants and, despite procedural differences, we reproduced findings with animal participants. We showed that pausing is jointly determined by past conditions of reinforcement and stimuli correlated with upcoming conditions. PMID:21541121

Williams, Dean C; Saunders, Kathryn J; Perone, Michael

2011-01-01

332

Role of the phosphatidylinositol 3-kinase\\/Akt and mTOR\\/P70S6-kinase pathways in the proliferation and apoptosis in multiple myeloma  

Microsoft Academic Search

Multiple myeloma (MM) is a plasma cell malignancy preliminary localized in the bone marrow and characterized by its capacity to disseminate. IL-6 and IGF-1 have been shown to mediate proliferative and anti-apoptotic signals in plasmocytes. However, in primary plasma-cell leukemia (PCL) and in end-stage aggressive extramedullar disease, the cytokine requirement for both effects may be not mandatory. This suggests that

Frédéric Pene; Yann-Erick Claessens; Odile Muller; Franck Viguié; Patrick Mayeux; François Dreyfus; Catherine Lacombe; Didier Bouscary

2002-01-01

333

Multiple Common Susceptibility Variants near BMP Pathway Loci GREM1, BMP4, and BMP2 Explain Part of the Missing Heritability of Colorectal Cancer  

PubMed Central

Genome-wide association studies (GWAS) have identified 14 tagging single nucleotide polymorphisms (tagSNPs) that are associated with the risk of colorectal cancer (CRC), and several of these tagSNPs are near bone morphogenetic protein (BMP) pathway loci. The penalty of multiple testing implicit in GWAS increases the attraction of complementary approaches for disease gene discovery, including candidate gene- or pathway-based analyses. The strongest candidate loci for additional predisposition SNPs are arguably those already known both to have functional relevance and to be involved in disease risk. To investigate this proposition, we searched for novel CRC susceptibility variants close to the BMP pathway genes GREM1 (15q13.3), BMP4 (14q22.2), and BMP2 (20p12.3) using sample sets totalling 24,910 CRC cases and 26,275 controls. We identified new, independent CRC predisposition SNPs close to BMP4 (rs1957636, P?=?3.93×10?10) and BMP2 (rs4813802, P?=?4.65×10?11). Near GREM1, we found using fine-mapping that the previously-identified association between tagSNP rs4779584 and CRC actually resulted from two independent signals represented by rs16969681 (P?=?5.33×10?8) and rs11632715 (P?=?2.30×10?10). As low-penetrance predisposition variants become harder to identify—owing to small effect sizes and/or low risk allele frequencies—approaches based on informed candidate gene selection may become increasingly attractive. Our data emphasise that genetic fine-mapping studies can deconvolute associations that have arisen owing to independent correlation of a tagSNP with more than one functional SNP, thus explaining some of the apparently missing heritability of common diseases. PMID:21655089

Dobbins, Sara E.; Tenesa, Albert; Jones, Angela M.; Howarth, Kimberley; Palles, Claire; Broderick, Peter; Jaeger, Emma E. M.; Farrington, Susan; Lewis, Annabelle; Prendergast, James G. D.; Pittman, Alan M.; Theodoratou, Evropi; Olver, Bianca; Walker, Marion; Penegar, Steven; Barclay, Ella; Whiffin, Nicola; Martin, Lynn; Ballereau, Stephane; Lloyd, Amy; Gorman, Maggie; Lubbe, Steven; Howie, Bryan; Marchini, Jonathan; Ruiz-Ponte, Clara; Fernandez-Rozadilla, Ceres; Castells, Antoni; Carracedo, Angel; Castellvi-Bel, Sergi; Duggan, David; Conti, David; Cazier, Jean-Baptiste; Campbell, Harry; Sieber, Oliver; Lipton, Lara; Gibbs, Peter; Martin, Nicholas G.; Montgomery, Grant W.; Young, Joanne; Baird, Paul N.; Gallinger, Steven; Newcomb, Polly; Hopper, John; Jenkins, Mark A.; Aaltonen, Lauri A.; Kerr, David J.; Cheadle, Jeremy; Pharoah, Paul; Casey, Graham; Houlston, Richard S.; Dunlop, Malcolm G.

2011-01-01

334

Multiple Effects of a Novel Epothilone Analog on Cellular Processes and Signaling Pathways Regulated by Rac1 GTPase in the Human Breast Cancer Cells  

PubMed Central

The epothilones are a class of microtubule inhibitors that exhibit a strong antitumor activity. UTD2 is a novel epothilone analog generated by genetic manipulation of the polyketide biosynthetic gene cluster. This study investigated the effects of UTD2 on the actin cytoskeleton and its critical regulators, and the signaling pathways which are essential for cell motility, growth and survival in MCF-7 breast cancer cells. Results showed that UTD2 inhibited the cellular functions of actin cytoskeleton, such as wound-closure, migration and invasion, as well as adhesion. Our study further demonstrated that UTD2 suppressed Rac1 GTPase activation and reduced the activity of PAK1, which is a downstream effector of Rac1, while the activity of Cdc42 was not affected. Additionally, the phosphorylation of p38 and ERK were significantly inhibited, but the phosphorylation of JNK remained the same after UTD2 treatment. Moreover, UTD2 inhibited the activity and mRNA expression of MMP-2, which plays a key role in cell motility. UTD2 also reduced the phosphorylation of Akt, which is an important signaling kinase regulating the cell survival through Rac1. Furthermore, UTD2 interrupted the synergy between Rac1 and Raf in focus formation assays. Taken together, these results indicated that UTD2 exerted multiple effects on the actin cytoskeleton and signaling pathways associated with Rac1. This study provided novel insights into the molecular mechanism of the antineoplastic and antimetastatic activities of epothilones. Our findings also suggest that the signaling pathways regulated by Rac1 may be evaluated as biomarkers for the response to therapy in clinical trials of epothilones. PMID:24757372

Zhang, Hong; An, Fan

2014-01-01

335

Inquiry in conversation: Exploring the multiple solution pathway (MSP) lesson structure as a means to progressive discourse in the science classroom  

NASA Astrophysics Data System (ADS)

This exploratory, descriptive study examined the way five chemistry teachers from four different schools enacted their visions of an activity labeled as the multiple solution pathway (MSP) lesson structure -- one in which students were given a relevant problem to solve and the opportunity to propose and explore several solutions to the problem. A theoretical and analytical framework for characterizing what transpired within these enactments was developed mainly out of Bereiter's principle of progressive discourse and its accompanying commitments, but also by drawing on Peirce's fallibilist epistemology, Gal'perin's notion of the orienting basis of an action, and Davydov's distinction between empirical and theoretical generalizations. Data from utterance-level discourse analysis of the videotaped lessons, supplemented by pre- and post-lesson interviews with both students and teachers was used to answer the research question: What is the nature of the interactions that occur during Multiple Solution Pathway (MSP) lessons and how are those interactions related to the structure of activity and the way in which ideas are explored within those lessons? The data showed that there were two general structures of activity utilized by the five teachers and that these different structures impacted the extent to which two of the progressive discourse commitments (expansion and openness) were supported. It also indicated that the teachers likely operated off a 'teacher as evaluator' metaphor and a discrepant event vision of the way the lesson should unfold, both features of which limited the extent to which progressive discourse was maintained in these lessons. Pedagogical implications for more fully realizing the potential of the MSP structure are presented.

Criswell, Brett A.

336

[The activation of the type I interferon signaling pathway in multiple sclerosis patients treated with russian analogue of ?-interferon-1b: transcriptome profiling data.  

PubMed

Implementation of the analogues of ?-interferon (?-IFN), produced by recombinant strains of E. coli (?-IFN-1b), for internal use in the Russian Federation for the treatment of multiple sclerosis (MS), implies a verification of their action at the transcriptome level in order to confirm the activation of the main signaling pathways involved in IFNb mechanism of action. In this work, the analysis is carried out for Infibeta (Generium, Russia). Using genome-wide transcriptional profiling with ILLUMINA HT-12 microarray, the differentially expressed genes in peripheral blood mononuclear cells of MS patients upon administration of Infibeta were studied. Comparison of gene expression levels in treatment-naive MS patients prior to first ?-IFN administration and 10 hours after it, identified 490 genes with significantly changed expression level, where 191 genes were up-regulated and 299 genes were down-regulated. Among the involved genes are those coding the components of the inflammatory system, innate and adaptive immunity, apoptosis, signal transduction, transcription, translation, degradation. Using gene set analysis, we confirmed the involvement of type I interferon signaling pathway genes and interferon-inducible genes in a patient's individual response to drug. Thus, the transcriptome profiling analysis allows concluding that the mechanism of action of Infibeta immunomodulatory drug is equal to that described for the original ?-IFN drugs. PMID:24662360

Danilova, L V; Popova, E V; Kulakova, O G; Tsareva, E Iu; Favorov, A V; Favorova, O O; Bo?ko, A N

2014-01-01

337

Regulation of Hxt3 and Hxt7 turnover converges on the Vid30 complex and requires inactivation of the Ras/cAMP/PKA pathway in Saccharomyces cerevisiae.  

PubMed

Eukaryotic cells adjust their intracellular protein complement as a mechanism to adapt to changing environmental signals. In Saccharomyces cerevisiae the hexose transporters Hxt3 and Hxt7 are expressed and function on the plasma membrane in high and low glucose abundance, respectively. By contrast, Hxt3 is endocytosed and degraded in the vacuole when cells are starved of glucose and Hxt7 in response to rapamycin treatment or when nitrogen is limiting. Yeast uses several signaling pathways, including the TORC1 and Ras/cAMP/Protein Kinase A (PKA) pathways, to adapt to nutrient changes in the environment. The multi-protein Vid30 complex (Vid30c), an E3 ubiquitin ligase required for the degradation of FBPase, assists in this adaptation process in a mechanism that is poorly understood. Here we show the endocytosis and the subsequent degradation of both Hxt3 and Hxt7, in response to different nutrient signals, is dependent on components of the Vid30c. Additionally, we define the signaling events required for the turnover of Hxt3 and Hxt7 by showing that Hxt3 turnover requires Ras2 and PKA inactivation, whereas Hxt7 turnover requires TORC1 and Ras2 inactivation. Further investigation led us to identify Rim15, a kinase that is inhibited by both the TORC1 and Ras/cAMP/PKA pathways, as a key downstream effector in signaling both turnover events. Finally, we show that the turnover of both Hxt3 and Hxt7 is dependent on the essential E3 ubiquitin ligase, Rsp5, indicating that the role of the Vid30c might be indirect of Hxt ubiquitylation. PMID:23227176

Snowdon, Chris; van der Merwe, George

2012-01-01

338

Two Stage Cadherin Kinetics Require Multiple Extracellular Domains but Not the Cytoplasmic Region*  

PubMed Central

Micropipette manipulation measurements quantified the pre-steady state binding kinetics between cell pairs mediated by Xenopus cleavage stage cadherin. The time-dependence of the intercellular binding probability exhibits a fast forming, low probability binding state, which transitions to a slower forming, high probability state. The biphasic kinetics are independent of the cytoplasmic region, but the transition to the high probability state requires the third extracellular domain EC3. Deleting either EC3 or EC3–5, or substituting Trp2 for Ala reduces the binding curves to a simple, monophasic rise in binding probability to a limiting plateau, as predicted for a single site binding mechanism. The two stage cadherin binding process reported here directly parallels previous biophysical studies, and confirms that the cadherin ectodomain governs the initial intercellular adhesion dynamics. PMID:17999960

Chien, Yuan-Hung; Jiang, Ning; Li, Fang; Zhang, Fang; Zhu, Cheng; Leckband, Deborah

2012-01-01

339

Modelling equilibrium shoreline response: application across multiple sites and minimum data collection requirements  

NASA Astrophysics Data System (ADS)

The ability to predict shoreline variability and trends for a range of potential future climate scenarios is of increasing interest to coastal scientists. Here we introduce a new shoreline equilibrium model driven by cross-shore processes via changes in non-dimensional fall velocity (i.e., sediment characteristics and wave steepness) and offshore wave power (Davidson et al., submitted). The equilibrium shoreline position is modeled based on a weighted time-average of past non-dimensional fall velocity following the work of Wright et al. (1985). When the prevailing wave conditions are steeper than the time varying equilibrium, the shoreline erodes as sand is expected to move offshore and form a breaker bar. Conversely, when waves are flatter, sand moves onshore and the shoreline builds seawards. The model is applied at a number of sites within Australia and the US to quantify model skill, and to examine free parameter sensitivity and generic transferability between differing sites. Further testing using real-world and synthetic data sets is used to determine the minimum data requirements for calibration of the model, providing useful guidance to future coastline monitoring program requirements. Model hindcasts at six locations within Australia indicate this simple cross-shore equilibrium shoreline model is capable of reproducing multi-year shoreline variability with significant skill. Shoreline variance explained by the model (currently driven only by cross-shore processes) is between 40% (downdrift of an Artificial surfing reef on an exposed open coast) to 66% percent (on a central location of a storm-driven embayed beach, Fig. 1).Hindcast results for the Narrabeen embayment at alongshore locations y=2200m (a), 2600m (b) and 3200m (c). R 2 ranged from 0.57 (y=2600m) to 0.66 (y=3200m). The thickness of the data curve (grey) indicates the potential measurement error.

Splinter, K.; Davidson, M. A.; Turner, I. L.

2012-12-01

340

Recombinant factor VIIa enhances platelet deposition from flowing haemophilic blood but requires the contact pathway to promote fibrin deposition.  

PubMed

In prior microfluidic studies with haemophilic blood perfused over collagen, we found that a severe deficiency (<1% factor level) reduced platelet and fibrin deposition, while a moderate deficiency (1-5%) only reduced fibrin deposition. We investigated: (i) the differential effect of rFVIIa (0.04-20 nm) on platelet and fibrin deposition, and (ii) the contribution of the contact pathway to rFVIIa-induced haemophilic blood clotting. Haemophilic or healthy blood with low and high corn trypsin inhibitor (CTI, 4 or 40 ?g mL(-1) ) was perfused over collagen at an initial venous wall shear rate of 100 s(-1) . At 100 s(-1) wall shear rate, where FXIIa leads to thrombin production without added tissue factor, FXI-deficient blood (3%) or severely FVIII-deficient blood (<1%) produced no fibrin at either CTI level. Whereas rFVIIa potently enhanced platelet deposition, fibrin generation was not rescued. Distinct from the high CTI condition, engagement of the contact pathway (low CTI) in moderately FVIII-deficient (3%) or moderately FIX-deficient blood (5%) resulted in enhanced platelet and fibrin deposition following 4 nm rFVIIa supplementation. In mildly FVIII-deficient blood (15%) at <24 h since haemostatic therapy, rFVIIa enhanced both platelet and fibrin generation in either CTI condition although fibrin was produced more quickly and abundantly in low CTI. For tissue factor-free conditions of severe haemophilic blood clotting, we conclude that rFVIIa reliably generates low levels of 'signaling' thrombin sufficient to enhance platelet deposition on collagen, but is insufficient to drive fibrin polymerization unless potentiated by the contact pathway. PMID:25311576

Li, R; Panckeri, K A; Fogarty, P F; Diamond, S L

2015-03-01

341

Multiple Gene Products and Sequences Required for Excision of the Mobilizable Integrated Bacteroides Element NBU1  

PubMed Central

NBU1 is an integrated 10.3-kbp Bacteroides element, which can excise and transfer to Bacteroides or Escherichia coli recipients, where it integrates into the recipient genome. NBU1 relies on large, >60-kbp, conjugative transposons for factors that trigger excision and for mobilization of the circular form to recipients. Previously, we showed that a single integrase gene, intN1, was necessary and sufficient for integration of NBU1 into its target site on the Bacteroides or E. coli genome. We now show that an unexpectedly large region of NBU1 is required for excision. This region includes, in addition to intN1, four open reading frames plus a large region downstream of the fourth gene, prmN1. This downstream sequence was designated XRS, for “excision-required sequence.” XRS contains the oriT of the circular form of NBU1 and about two-thirds of the adjacent mobilization gene, mobN1. This is the first time an oriT, which is involved in conjugal transfer of the circular form, has been implicated in excision. Disruption of the gene immediately downstream of intN1, orf2, completely abolished excision. The next open reading frame, orf2x, was too small to be disrupted, so we still do not know whether it plays a role in the excision reaction. Deletions were made in each of two open reading frames downstream of orf2x, orf3 and prmN1. Both of these deletions abolished excision, indicating that these genes are also essential for excision. Attempts to complement various mutations in the excision region led us to realize that a portion of the excision region carrying prmN1 and part of the XRS (XRSHIII) inhibited excision when provided in trans on a multicopy plasmid (8 to 10 copies per cell). However, a fragment carrying prmN1, XRS, and the entire mobilization gene, mobN1, did not have this effect. The smaller fragment may be interfering with excision by attracting proteins made by the intact NBU1 and thus removing them from the excision complex. Our results show clearly that excision is a complex process that involves several proteins and a cis-acting region (XRS) which includes the oriT. We suggest that this complex excision machinery may be necessary to allow NBU1 to coordinate nicking at the ends during excision and nicking at the oriT during conjugal transfer, to prevent premature nicking at the oriT before NBU1 has excised and circularized. PMID:10648516

Shoemaker, Nadja B.; Wang, Gui-Rong; Salyers, Abigail A.

2000-01-01

342

Multiple gene products and sequences required for excision of the mobilizable integrated Bacteroides element NBU1.  

PubMed

NBU1 is an integrated 10.3-kbp Bacteroides element, which can excise and transfer to Bacteroides or Escherichia coli recipients, where it integrates into the recipient genome. NBU1 relies on large, >60-kbp, conjugative transposons for factors that trigger excision and for mobilization of the circular form to recipients. Previously, we showed that a single integrase gene, intN1, was necessary and sufficient for integration of NBU1 into its target site on the Bacteroides or E. coli genome. We now show that an unexpectedly large region of NBU1 is required for excision. This region includes, in addition to intN1, four open reading frames plus a large region downstream of the fourth gene, prmN1. This downstream sequence was designated XRS, for "excision-required sequence." XRS contains the oriT of the circular form of NBU1 and about two-thirds of the adjacent mobilization gene, mobN1. This is the first time an oriT, which is involved in conjugal transfer of the circular form, has been implicated in excision. Disruption of the gene immediately downstream of intN1, orf2, completely abolished excision. The next open reading frame, orf2x, was too small to be disrupted, so we still do not know whether it plays a role in the excision reaction. Deletions were made in each of two open reading frames downstream of orf2x, orf3 and prmN1. Both of these deletions abolished excision, indicating that these genes are also essential for excision. Attempts to complement various mutations in the excision region led us to realize that a portion of the excision region carrying prmN1 and part of the XRS (XRS(HIII)) inhibited excision when provided in trans on a multicopy plasmid (8 to 10 copies per cell). However, a fragment carrying prmN1, XRS, and the entire mobilization gene, mobN1, did not have this effect. The smaller fragment may be interfering with excision by attracting proteins made by the intact NBU1 and thus removing them from the excision complex. Our results show clearly that excision is a complex process that involves several proteins and a cis-acting region (XRS) which includes the oriT. We suggest that this complex excision machinery may be necessary to allow NBU1 to coordinate nicking at the ends during excision and nicking at the oriT during conjugal transfer, to prevent premature nicking at the oriT before NBU1 has excised and circularized. PMID:10648516

Shoemaker, N B; Wang, G R; Salyers, A A

2000-02-01

343

Relationship between Optical Coherence Tomography and Electrophysiology of the Visual Pathway in Non-Optic Neuritis Eyes of Multiple Sclerosis Patients  

PubMed Central

Purpose Loss of retinal ganglion cells in in non-optic neuritis eyes of Multiple Sclerosis patients (MS-NON) has recently been demonstrated. However, the pathological basis of this loss at present is not clear. Therefore, the aim of the current study was to investigate associations of clinical (high and low contrast visual acuity) and electrophysiological (electroretinogram and multifocal Visual Evoked Potentials) measures of the visual pathway with neuronal and axonal loss of RGC in order to better understand the nature of this loss. Methods Sixty-two patients with relapsing remitting multiple sclerosis with no previous history of optic neuritis in at least one eye were enrolled. All patients underwent a detailed ophthalmological examination in addition to low contrast visual acuity, Optical Coherence Tomography, full field electroretinogram (ERG) and multifocal visual evoked potentials (mfVEP). Results There was significant reduction of ganglion cell layer thickness, and total and temporal retinal nerve fibre layer (RNFL) thickness (p<0.0001, 0.002 and 0.0002 respectively). Multifocal VEP also demonstrated significant amplitude reduction and latency delay (p<0.0001 for both). Ganglion cell layer thickness, total and temporal RNFL thickness inversely correlated with mfVEP latency (r?=??0.48, p<0.0001 respectively; r?=??0.53, p<0.0001 and r?=??0.59, p<0.0001 respectively). Ganglion cell layer thickness, total and temporal RNFL thickness also inversely correlated with the photopic b-wave latency (r?=??0.35, p?=?0.01; r?=??0.33, p?=?0.025; r?=??0.36, p?=?0.008 respectively). Multivariate linear regression model demonstrated that while both factors were significantly associated with RGC axonal and neuronal loss, the estimated predictive power of the posterior visual pathway damage was considerably larger compare to retinal dysfunction. Conclusion The results of our study demonstrated significant association of RGC axonal and neuronal loss in NON-eyes of MS patients with both retinal dysfunction and post-chiasmal damage of the visual pathway. PMID:25166273

Sriram, Prema; Wang, Chenyu; Yiannikas, Con; Garrick, Raymond; Barnett, Michael; Parratt, John; Graham, Stuart L.; Arvind, Hemamalini; Klistorner, Alexander

2014-01-01

344

Phenotypically linked dichotomy in sea turtle foraging requires multiple conservation approaches.  

PubMed

Marine turtles undergo dramatic ontogenic changes in body size and behavior, with the loggerhead sea turtle, Caretta caretta, typically switching from an initial oceanic juvenile stage to one in the neritic, where maturation is reached and breeding migrations are subsequently undertaken every 2-3 years. Using satellite tracking, we investigated the migratory movements of adult females from one of the world's largest nesting aggregations at Cape Verde, West Africa. In direct contrast with the accepted life-history model for this species, results reveal two distinct adult foraging strategies that appear to be linked to body size. The larger turtles (n = 3) foraged in coastal waters, whereas smaller individuals (n = 7) foraged oceanically. The conservation implications of these findings are profound, with the population compartmentalized into habitats that may be differentially impacted by fishery threats in what is a global fishing hotspot. Although the protection of discrete areas containing coastal individuals may be attainable, the more numerous pelagic individuals are widely dispersed with individuals roaming over more than half a million square kilometers. Therefore, mitigation of fisheries by-catch for sea turtles in the east Atlantic will likely require complex and regionally tailored actions to account for this dichotomous behavior. PMID:16713955

Hawkes, Lucy A; Broderick, Annette C; Coyne, Michael S; Godfrey, Matthew H; Lopez-Jurado, Luis-Felipe; Lopez-Suarez, Pedro; Merino, Sonia Elsy; Varo-Cruz, Nuria; Godley, Brendan J

2006-05-23

345

Multiple risk pathways for schizophrenia converge in serine racemase knockout mice, a mouse model of NMDA receptor hypofunction  

PubMed Central

Schizophrenia is characterized by reduced hippocampal volume, decreased dendritic spine density, altered neuroplasticity signaling pathways, and cognitive deficits associated with impaired hippocampal function. We sought to determine whether this diverse pathology could be linked to NMDA receptor (NMDAR) hypofunction, and thus used the serine racemase-null mutant mouse (SR?/?), which has less than 10% of normal brain d-serine, an NMDAR coagonist. We found that d-serine was necessary for the maintenance of long-term potentiation in the adult hippocampal dentate gyrus and for full NMDAR activity on granule cells. SR?/? mice had reduced dendritic spines and hippocampal volume. These morphological changes were paralleled by diminished BDNF/Akt/mammalian target of rapamycin (mTOR) signaling and impaired performance on a trace-conditioning memory task. Chronic d-serine treatment normalized the electrophysiological, neurochemical, and cognitive deficits in SR?/? mice. These results demonstrate that NMDAR hypofunction can reproduce the numerous hippocampal deficits associated with schizophrenia, which can be reversed by chronic peripheral d-serine treatment. PMID:23729812

Balu, Darrick T.; Li, Yan; Puhl, Matthew D.; Benneyworth, Michael A.; Basu, Alo C.; Takagi, Shunsuke; Bolshakov, Vadim Y.; Coyle, Joseph T.

2013-01-01

346

Fragmentation pathways of polycyclic polyisoprenylated benzophenones and degradation profile of nemorosone by multiple-stage tandem mass spectrometry.  

PubMed

Nemorosone is a polycyclic polyisoprenylated benzophenone (PPBs) with strong cytotoxic activity. It is the major constituent of Clusia rosea floral resin and brown Cuban propolis. Other PPBs found in Cuban propolis are oxidized and cyclized derivatives of nemorosone. The instability of PPBs carrying an enolizable 1,3-diketone system has been suggested, and the elucidation of this aspect is very fundamental for the evaluation of their biologic activity. Electrospray ionization multistage tandem mass spectrometry (ESI-MS(n)) was employed to shed light on the origin of these derivatives of nemorosone and to define the stability of this natural product. For this purpose, we initially performed MS(n) experiments on seven related PPBs to obtain useful information for structural characterization of this class of compounds and to identify the degradation products of nemorosone. The proposed fragmentation pathways, supported by exact mass measurements, allowed the nature of side chains on the bicyclo core and the type and position of their modifications to be established. In a second part, the degradation profile of nemorosone under different conditions was investigated to assess the possible effects of isolation procedures, climatic, and storage conditions on its stability. Our results reveal that nemorosone undergoes rapid degradation in n-hexane and chloroform solutions. The degradation products, identified by HPLC-ESI/MS(n) and NMR, are identical to derivatives of nemorosone previously isolated from propolis and plants. Thus, these PPBs are artefacts formed predominantly during the extraction and purification procedures. PMID:19540134

Piccinelli, Anna Lisa; Campone, Luca; Dal Piaz, Fabrizio; Cuesta-Rubio, Osmany; Rastrelli, Luca

2009-09-01

347

Multiple signaling pathways involved in stimulation of osteoblast differentiation by N-methyl-D-aspartate receptors activation in vitro  

PubMed Central

Aim: Glutamate receptors are expressed in osteoblastic cells. The present study was undertaken to investigate the mechanisms underlying the stimulation of osteoblast differentiation by N-methyl-D-aspartate (NMDA) receptor activation in vitro. Methods: Primary culture of osteoblasts was prepared from SD rats. Microarray was used to detect the changes of gene expression. The effect of NMDA receptor agonist or antagonist on individual gene was examined using RT-PCR. The activity of alkaloid phosphotase (ALP) was assessed using a commercial ALP staining kit. Results: Microarray analyses revealed that 10 genes were up-regulated by NMDA (0.5 mmol/L) and down-regulated by MK801 (100 ?mol/L), while 13 genes down-regulated by NMDA (0.5 mmol/L) and up-regulated by MK801 (100 ?mol/L). Pretreatment of osteoblasts with the specific PKC inhibitor Calphostin C (0.05 ?mol/L), the PKA inhibitor H-89 (20 nmol/L), or the PI3K inhibitor wortmannin (100 nmol/L) blocked the ALP activity increase caused by NMDA (0.5 mmol/L). Furthermore, NMDA (0.5 mmol/L) rapidly increased PI3K phosphorylation, which could be blocked by pretreatment of wortmannin (100 nmol/L). Conclusion: The results suggest that activation of NMDA receptors stimulates osteoblasts differentiation through PKA, PKC, and PI3K signaling pathways, which is a new role for glutamate in regulating bone remodeling. PMID:21685927

Li, Jie-li; Zhao, Lin; Cui, Bin; Deng, Lian-fu; Ning, Guang; Liu, Jian-min

2011-01-01

348

Direct observation of kinetic traps associated with structural transformations leading to multiple pathways of S-layer assembly.  

PubMed

The concept of a folding funnel with kinetic traps describes folding of individual proteins. Using in situ Atomic Force Microscopy to investigate S-layer assembly on mica, we show this concept is equally valid during self-assembly of proteins into extended matrices. We find the S-layer-on-mica system possesses a kinetic trap associated with conformational differences between a long-lived transient state and the final stable state. Both ordered tetrameric states emerge from clusters of the monomer phase, however, they then track along two different pathways. One leads directly to the final low-energy state and the other to the kinetic trap. Over time, the trapped state transforms into the stable state. By analyzing the time and temperature dependencies of formation and transformation we find that the energy barriers to formation of the two states differ by only 0.7 kT, but once the high-energy state forms, the barrier to transformation to the low-energy state is 25 kT. Thus the transient state exhibits the characteristics of a kinetic trap in a folding funnel. PMID:22822216

Shin, Seong-Ho; Chung, Sungwook; Sanii, Babak; Comolli, Luis R; Bertozzi, Carolyn R; De Yoreo, James J

2012-08-01

349

A novel vasculo-angiogenic effect of cilostazol mediated by cross-talk between multiple signalling pathways including the ERK/p38 MAPK signalling transduction cascade.  

PubMed

Cilostazol is an anti-platelet agent with vasodilatory activity that acts by increasing intracellular concentrations of cAMP. Recent reports have suggested that cilostazol may promote angiogenesis. In the present study, we have investigated the effect of cilostazol in promoting angiogenesis and vasculogenesis in a hindlimb ischaemia model and have also examined its potential mechanism of action in vitro and in vivo. We found that cilostazol treatment significantly increased colony formation by human early EPCs (endothelial progenitor cells) through a mechanism involving the activation of cAMP/PKA (protein kinase A), PI3K (phosphoinositide 3-kinase)/Akt/eNOS (endothelial NO synthase) and ERK (extracellular-signal-regulated kinase)/p38 MAPK (mitogen-activated protein kinase) signalling pathways. Cilostazol also enhanced proliferation, chemotaxis, NO production and vascular tube formation in HUVECs (human umbilical vein endothelial cells) through activation of multiple signalling pathways downstream of PI3K/Akt/eNOS. Cilostazol up-regulated VEGF (vascular endothelial growth factor)-A165 expression and secretion of VEGF-A in HUVECs through activation of the PI3K/Akt/eNOS pathway. In a mouse hindlimb ischaemia model, recovery of blood flow ratio (ipsilateral/contralateral) 14 days after surgery was significantly improved in cilostazol-treated mice (10 mg/kg of body weight) compared with vehicle-treated controls (0.63±0.07 and 0.43±0.05 respectively, P<0.05). Circulating CD34+ cells were also increased in cilostazol-treated mice (3614±670 compared with 2151±608 cells/ml, P<0.05). Expression of VEGF and phosphorylation of PI3K/Akt/eNOS and ERK/p38 MAPK in ischaemic muscles were significantly enhanced by cilostazol. Our data suggest that cilostazol produces a vasculo-angiogenic effect by up-regulating a broad signalling network that includes the ERK/p38 MAPK, VEGF-A165, PI3K/Akt/eNOS and cAMP/PKA pathways. PMID:22339730

Chao, Ting-Hsing; Tseng, Shih-Ya; Li, Yi-Heng; Liu, Ping-Yen; Cho, Chung-Lung; Shi, Guey-Yueh; Wu, Hua-Lin; Chen, Jyh-Hong

2012-08-01

350

Thymic medullary epithelium and thymocyte self tolerance require cooperation between CD28-CD80/86 and CD40-CD40L costimulatory pathways  

PubMed Central

A critical process during thymic development of the T cell repertoire is the induction of self-tolerance. Tolerance in developing T cells is highly dependent on medullary thymic epithelial cells (mTEC) and mTEC development in turn requires signals from mature single positive (SP) thymocytes, a bidirectional relationship termed thymus crosstalk. We show that CD28-CD80/86 and CD40-CD40L costimulatory interactions, which mediate negative selection and self-tolerance, upregulate expression of LT?, LT? and RANK in the thymus and are necessary for medullary development. Combined absence of CD28-CD80/86 and CD40-CD40L results in profound deficiency in mTEC development comparable to that observed in the absence of SP thymocytes. This requirement for costimulatory signaling is maintained even in a TCR transgenic model of high affinity TCR-ligand interactions. CD4 thymocytes maturing in the altered thymic epithelial environment of CD40/CD80/86 KO mice are highly autoreactive in vitro and are lethal in congenic adoptive transfer in vivo, demonstrating a critical role for these costimulatory pathways in self-tolerance as well as thymic epithelial development. These findings demonstrate that cooperativity between CD28-CD80/86 and CD40-CD40L pathways is required for normal medullary epithelium and for maintenance of self-tolerance in thymocyte development. PMID:24337745

Williams, Joy A.; Zhang, Jingjing; Jeon, Hyein; Nitta, Takeshi; Ohigashi, Izumi; Klug, David; Kruhlak, Michael J.; Choudhury, Baishakhi; Sharrow, Susan O.; Granger, Larry; Adams, Anthony; Eckhaus, Michael A.; Jenkinson, S. Rhiannon; Richie, Ellen R.; Gress, Ronald E.; Takahama, Yousuke; Hodes, Richard J.

2014-01-01

351

Ras pathways in Caenorhabditis elegans.  

PubMed

The let-60 ras gene of Caenorhabditis elegans is required for multiple aspects of development. The vulvar differentiation pathway is the most intensively studied of these, but the ras pathway has now been shown to also be essential for male spicule development. Using vulval differentiation, molecular genetic techniques are now being used to study structure/function relationships of particular signaling components and to identify new positively and negatively acting proteins of Ras-mediated signaling pathways. Mutations affecting LET-23, a receptor tyrosine kinase homolog, which cause tissue-specific defects have been localized to the carboxyl terminus. SH2 domain specificity has been analyzed through Src/SEM-5 chimeric proteins in transgenic nematodes. A mitogen-activated protein kinase that acts downstream of LET-60 Ras in vulval differentiation has been identified. Negative regulatory genes have been cloned and found to encode novel proteins and a clathrin adaptor protein. PMID:7749323

Kayne, P S; Sternberg, P W

1995-02-01

352

UP12, a novel ursolic acid derivative with potential for targeting multiple signaling pathways in hepatocellular carcinoma.  

PubMed

Targeting cancer cell glucose metabolism is a promising strategy for cancer therapy. In past approaches to cancer drug discovery, ursolic acid (UA) has been chemically modified to improve its antitumor activities and bioavailability. Here, a novel ursolic acid (UA) derivative UP12 was developed via computer-aided drug design to explore potent anti-cancer agents and to examine possible mechanisms. The structural docking analyses suggested that UP12 could bind to the active sites of glucokinase (GK), glucose transporter 1 (GLUT1) and ATPase, which are the main enzymes involved in cancer glucose metabolism. We further investigated the synergistic effect between UP12 and glycolysis inhibitor 2-deoxy-d-glucose (2-DG) in inhibiting glucose metabolism of cancer cells. The pharmacological results showed that the combination enhanced depletion of intracellular ATP and decrease in lactate production, and pushed more cancer cells arrested in the S and G2/M cycle phases. The combination selectively down-regulated the expression of Bcl-2 and HKII proteins, up-regulated the expression of Bax and p53, and collectively resulted in enhanced apoptosis related to caspase-3, -8, and -9 activities, in addition to inhibition on the cell mitochondrial membrane potential. The animal studies further demonstrated that the combination exhibited significant antitumor activity without obvious toxicity. In summary, UP12 can interfere cancer cell metabolism pathway and further enhance the therapeutic effects of 2-DG likely through synergistic suppression of cancer cell glucose metabolism, making UP12 a likely new candidate for anti-cancer drug development. PMID:25522955

Dong, Haiyan; Yang, Xiang; Xie, Jingjing; Xiang, Liping; Li, Yuanfang; Ou, Minrui; Chi, Ting; Liu, Zhenhua; Yu, Suhong; Gao, Yu; Chen, Jianzhong; Shao, Jingwei; Jia, Lee

2015-01-15

353

A requirement for the rac1 GTPase in the signal transduction pathway leading to cardiac myocyte hypertrophy.  

PubMed Central

We have used adenoviral-mediated gene transfer of a constitutively active (V12rac1) and dominant negative (N17rac1) isoform of rac1 to assess the role of this small GTPase in cardiac myocyte hypertrophy. Expression of V12rac1 in neonatal cardiac myocytes results in sarcomeric reorganization and an increase in cell size that is indistinguishable from ligand-stimulated hypertrophy. In addition, V12rac1 expression leads to an increase in atrial natriuretic peptide secretion. In contrast, expression of N17rac1, but not a truncated form of Raf-1, attenuated the morphological hypertrophy associated with phenylephrine stimulation. Consistent with the observed effects on morphology, expression of V12rac1 resulted in an increase in new protein synthesis, while N17rac1 expression inhibited phenylephrine-induced leucine incorporation. These results suggest rac1 is an essential element of the signaling pathway leading to cardiac myocyte hypertrophy. PMID:9727061

Pracyk, J B; Tanaka, K; Hegland, D D; Kim, K S; Sethi, R; Rovira, I I; Blazina, D R; Lee, L; Bruder, J T; Kovesdi, I; Goldshmidt-Clermont, P J; Irani, K; Finkel, T

1998-01-01

354

Erythropoietin activates two distinct signaling pathways required for the initiation and the elongation of c-myc.  

PubMed

Erythropoietin (Epo) stimulation of erythroid cells results in the activation of several kinases and a rapid induction of c-myc expression. Protein kinase C is necessary for Epo up-regulation of c-myc by promoting elongation at the 3'-end of exon 1. PKCepsilon mediates this signal. We now show that Epo triggers two signaling pathways to c-myc. Epo rapidly up-regulated Myc protein in BaF3-EpoR cells. The phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 blocked Myc up-regulation in a concentration-dependent manner but had no effect on the Epo-induced phosphorylation of ERK1 and ERK2. LY294002 also had no effect on Epo up-regulation of c-fos. MEK1 inhibitor PD98059 blocked both the c-myc and the c-fos responses to Epo. PD98059 and the PKC inhibitor H7 also blocked the phosphorylation of ERK1 and ERK2. PD98059 but not LY294002 inhibited Epo induction of ERK1 and ERK2 phosphorylation in normal erythroid cells. LY294002 blocked transcription of c-myc at exon 1. PD98059 had no effect on transcription from exon 1 but, rather, blocked Epo-induced c-myc elongation at the 3'-end of exon 1. These results identify two Epo signaling pathways to c-myc, one of which is PI3K-dependent operating on transcriptional initiation, whereas the other is mitogen-activated protein kinase-dependent operating on elongation. PMID:11483613

Chen, C; Sytkowski, A J

2001-10-19

355

Erythropoietin activates two distinct signaling pathways required for the initiation and the elongation of c-myc  

NASA Technical Reports Server (NTRS)

Erythropoietin (Epo) stimulation of erythroid cells results in the activation of several kinases and a rapid induction of c-myc expression. Protein kinase C is necessary for Epo up-regulation of c-myc by promoting elongation at the 3'-end of exon 1. PKCepsilon mediates this signal. We now show that Epo triggers two signaling pathways to c-myc. Epo rapidly up-regulated Myc protein in BaF3-EpoR cells. The phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 blocked Myc up-regulation in a concentration-dependent manner but had no effect on the Epo-induced phosphorylation of ERK1 and ERK2. LY294002 also had no effect on Epo up-regulation of c-fos. MEK1 inhibitor PD98059 blocked both the c-myc and the c-fos responses to Epo. PD98059 and the PKC inhibitor H7 also blocked the phosphorylation of ERK1 and ERK2. PD98059 but not LY294002 inhibited Epo induction of ERK1 and ERK2 phosphorylation in normal erythroid cells. LY294002 blocked transcription of c-myc at exon 1. PD98059 had no effect on transcription from exon 1 but, rather, blocked Epo-induced c-myc elongation at the 3'-end of exon 1. These results identify two Epo signaling pathways to c-myc, one of which is PI3K-dependent operating on transcriptional initiation, whereas the other is mitogen-activated protein kinase-dependent operating on elongation.

Chen, C.; Sytkowski, A. J.

2001-01-01

356

The essential Ubc4/Ubc5 function in yeast is HECT E3-dependent, and RING E3-dependent pathways require only monoubiquitin transfer by Ubc4.  

PubMed

The ubiquitin (Ub)-conjugating enzymes Ubc4 and Ubc5 are involved in a variety of ubiquitination pathways in yeast, including Rsp5- and anaphase-promoting complex (APC)-mediated pathways. We have found the double deletion of UBC4 and UBC5 genes in yeast to be lethal. To investigate the essential pathway disrupted by the ubc4/ubc5 deletion, several point mutations were inserted in Ubc4. The Ubc4 active site mutation C86A and the E3-binding mutations A97D and F63A were both unable to rescue the lethal phenotype, indicating that an active E3/E2?Ub complex is required for the essential function of Ubc4/Ubc5. A mutation that specifically eliminates RING E3-catalyzed isopeptide formation but not HECT E3 transthiolation (N78S-Ubc4) rescued the lethal phenotype. Thus, the essential redundant function performed by Ubc4 and Ubc5 in yeast is with a HECT-type E3, likely the only essential HECT in yeast, Rsp5. Our results also suggest that Ubc1 can weakly replace Ubc4 to transfer mono-Ub with APC, but Ubc4 cannot replace Ubc1 for poly-Ub chain extension on APC substrates. Finally, the backside Ub-binding mutant S23R-Ubc4 has no observable effect in yeast. Together, our results are consistent with a model in which Ubc4 and Ubc5 are 1) the primary E2s for Rsp5 in yeast and 2) act as monoubiquitinating E2s in RING E3-catalyzed pathways, in contrast to the processive human ortholog UbcH5. PMID:21357418

Stoll, Kate E; Brzovic, Peter S; Davis, Trisha N; Klevit, Rachel E

2011-04-29

357

Pathophysiological processes in multiple sclerosis: focus on nuclear factor erythroid-2-related factor 2 and emerging pathways  

PubMed Central

Multiple sclerosis (MS) is a disease of the central nervous system that is characterized by the demyelination of neuronal axons. Four different patterns of demyelination have been described, showing the heterogeneity in the immunopathologic processes involved in the demyelination. This review will focus on reactive oxygen species (ROS)-related inflammation in MS. Special emphasis will be placed on the nuclear factor erythroid-2-related factor 2 (Nrf2) as it regulates the transcription of ROS-protective genes. In the cytosol, Nrf2 binds to Keap1 (Kelch-like ECH-associated protein 1), and together they are degraded by the 26S proteasome after ubiquitination. If challenged by ROS Nrf2, binding to Keap1 is abrogated, and it translocates into the nucleus. Here it binds to the antioxidant response element and to a small protein termed Maf (musculoaponeurotic fibrosarcoma oncogene homolog). This leads to an enhanced transcription of ROS protective genes and represents the physiological answer against ROS challenge. It has been shown that dimethyl fumarate (DMF) has the same effect and leads to an enhanced transcription of ROS-protective genes. This response is mediated through a reduced binding of Nrf2 to Keap1, thus resulting in a higher level of free Nrf2 in the cytosol. Consequently, more Nrf2 translocates to the nucleus, promoting transcription of its target genes. DMF has been used for the treatment of psoriasis for many years in Germany without the occurrence of major side effects. In psoriasis, DMF reduces ROS-related inflammation in skin. A DMF analog, BG-12, was recently approved for the treatment of relapsing-remitting MS by the European Union and the US Food and Drug Administration. As an oral formulation, it gives patients a convenient and effective alternative to the injectable immune modulators in the long-term treatment of MS. PMID:24591852

Arnold, Philipp; Mojumder, Deb; DeToledo, John; Lucius, Ralph; Wilms, Henrik

2014-01-01

358

Binding of the wheat germ lectin to Cryptococcus neoformans chitooligomers affects multiple mechanisms required for fungal pathogenesis  

PubMed Central

The principal capsular component of Cryptococcus neoformans, glucuronoxylomannan (GXM), interacts with surface glycans, including chitin-like oligomers. Although the role of GXM in cryptococcal infection has been well explored, there is no information on how chitooligomers affect fungal pathogenesis. In this study, surface chitooligomers of C. neoformans were blocked through the use of the wheat germ lectin (WGA) and the effects on animal pathogenesis, interaction with host cells, fungal growth and capsule formation were analyzed. Treatment of C. neoformans cells with WGA followed by infection of mice delayed mortality relative to animals infected with untreated fungal cells. This observation was associated with reduced brain colonization by lectin-treated cryptococci. Blocking chitooligomers also rendered yeast cells less efficient in their ability to associate with phagocytes. WGA did not affect fungal viability, but inhibited GXM release to the extracellular space and capsule formation. In WGA-treated yeast cells, genes that are involved in capsule formation and GXM traffic had their transcription levels decreased in comparison with untreated cells. Our results suggest that cellular pathways required for capsule formation and pathogenic mechanisms are affected by blocking chitin-derived structures at the cell surface of C. neoformans. Targeting chitooligomers with specific ligands may reveal new therapeutic alternatives to control cryptococcosis. PMID:23608320

Fonseca, Fernanda L.; Guimarães, Allan J.; Kmetzsch, Lívia; Dutra, Fabianno F.; Silva, Fernanda D.; Taborda, Carlos P.; Araujo, Glauber de S.; Frases, Susana; Staats, Charley C.; Bozza, Marcelo T.; Schrank, Augusto; Vainstein, Marilene H.; Nimrichter, Leonardo; Casadevall, Arturo; Rodrigues, Marcio L.

2015-01-01

359

The Cpc1 regulator of the cross-pathway control of amino acid biosynthesis is required for pathogenicity of the vascular pathogen Verticillium longisporum.  

PubMed

The plant-pathogenic fungus Verticillium longisporum is a causal agent of early senescence and ripening in cruciferous crops like Brassica napus. Verticillium wilts have become serious agricultural threats in recent decades. Verticillium species infect host plants through the roots and colonize xylem vessels of the host plant. The xylem fluid provides an environment with limited carbon sources and unbalanced amino acid supply, which requires V. longisporum to induce the cross-pathway control of amino acid biosynthesis. RNA-mediated gene silencing reduced the expression of the two CPC1 isogenes (VlCPC1-1 and VlCPC1-2) of the allodiploid V. longisporum up to 85%. VlCPC1 encodes the conserved transcription factor of the cross-pathway control. The silenced mutants were highly sensitive to amino-acid starvation, and the infected plants showed significantly fewer symptoms such as stunting or early senescence in oilseed rape plant infection assays. Consistently, deletion of single CPC1 of the haploid V. dahliae resulted in strains that are sensitive to amino-acid starvation and cause strongly reduced symptoms in the plant-host tomato (Solanum lycopersicum). The allodiploid V. longisporum and the haploid V. dahliae are the first phytopathogenic fungi that were shown to require CPC1 for infection and colonization of their respective host plants, oilseed rape and tomato. PMID:23883358

Timpner, Christian; Braus-Stromeyer, Susanna A; Tran, Van Tuan; Braus, Gerhard H

2013-11-01

360

Functional roles of multiple feedback loops in extracellular signal-regulated kinase and Wnt signaling pathways that regulate epithelial-mesenchymal transition.  

PubMed

Epithelial-mesenchymal transition (EMT) is a key event in the generation of invasive tumor cells. A hallmark of EMT is the repression of E-cadherin expression, which is regulated by various signal transduction pathways including extracellular signal-regulated kinase (ERK) and Wnt. These pathways are highly interconnected via multiple coupled feedback loops (CFL). As the function of such coupled feedback regulations is difficult to analyze experimentally, we used a systems biology approach where computational models were designed to predict biological effects that result from the complex interplay of CFLs. Using epidermal growth factor (EGF) and Wnt as input and E-cadherin transcriptional regulation as output, we established an ordinary differential equation model of the ERK and Wnt signaling network containing six feedback links and used extensive computer simulations to analyze the effects of these feedback links in isolation and different combinations. The results show that the feedbacks can generate a rich dynamic behavior leading to various dose-response patterns and have a decisive role in determining network responses to EGF and Wnt. In particular, we made two important findings: first, that coupled positive feedback loops composed of phosphorylation of Raf kinase inhibitor RKIP by ERK and transcriptional repression of RKIP by Snail have an essential role in causing a switch-like behavior of E-cadherin expression; and second, that RKIP expression inhibits EMT progression by preventing E-cadherin suppression. Taken together, our findings provide us with a system-level understanding of how RKIP can regulate EMT progression and may explain why RKIP is downregulated in so many metastatic cancer cells. PMID:20736375

Shin, Sung-Young; Rath, Oliver; Zebisch, Armin; Choo, Sang-Mok; Kolch, Walter; Cho, Kwang-Hyun

2010-09-01

361

Expression Profiling of Vulvar Carcinoma: Clues for Deranged Extracellular Matrix Remodeling and Effects on Multiple Signaling Pathways Combined with Discrete Patient Subsets12  

PubMed Central

The molecular mechanisms of vulvar squamous cell carcinoma (VSCC) remain obscure. To this end, we investigated systematically for the first time the expression profile of VSCC using the microarray technology, in a total of 11 snap-frozen samples, from five VSCC patients covering early and advanced stages of VSCC undergoing radical surgery and from six matched healthy controls. All experiments were performed using Affymetrix Human Genome U133A 2.0 oligonucleotide arrays, covering 22,277 probe sets. Genes were filtered and analyzed using analysis of variance, t test, fold-change calculations, and unsupervised hierarchical cluster analysis. Further processing included functional analysis and overrepresentation calculations based on Gene Ontology, Database for Annotation, Visualization, and Integrated Discovery, and Ingenuity Pathway Analysis. The molecular phenotypes of VSCC patients exhibited significant and discrete transcriptional differences from the healthy controls, whereas principal component analysis documented that this separation is mediated by a consistent set of gene expression differences. We detected 1077 genes (306 upregulated and 771 downregulated) that were differentially expressed between VSCC patients and healthy controls by at least twofold (P < .01), whereas a novel subset of patients was revealed displaying a distinct pattern of 125 upregulated genes involved in multiple cellular processes. Functional analysis of the 1077 genes documented their involvement in more than 50 signaling pathways, such as PTEN, oncostatin M, and extracellular signal-regulated kinase signaling, affecting extracellular matrix remodeling and invasion. Comparison of our data set with those of the single VIN study revealed that the two entities share a limited number of genes and display unique features. PMID:21966547

Pappa, Kalliopi I; Jacob-Hirsch, Jasmine; Vlachos, George D; Christodoulou, Ioanna; Partsinevelos, George; Amariglio, Ninette; Markaki, Sofia; Antsaklis, Aris; Anagnou, Nicholas P

2011-01-01

362

Deletion of Atbf1/Zfhx3 In Mouse Prostate Causes Neoplastic Lesions, Likely by Attenuation of Membrane and Secretory Proteins and Multiple Signaling Pathways  

PubMed Central

The ATBF1/ZFHX3 gene at 16q22 is the second most frequently mutated gene in human prostate cancer and has reduced expression or mislocalization in several types of human tumors. Nonetheless, the hypothesis that ATBF1 has a tumor suppressor function in prostate cancer has not been tested. In this study, we examined the role of ATBF1 in prostatic carcinogenesis by specifically deleting Atbf1 in mouse prostatic epithelial cells. We also examined the effect of Atbf1 deletion on gene expression and signaling pathways in mouse prostates. Histopathologic analyses showed that Atbf1 deficiency caused hyperplasia and mouse prostatic intraepithelial neoplasia (mPIN) primarily in the dorsal prostate but also in other lobes. Hemizygous deletion of Atbf1 also increased the development of hyperplasia and mPIN, indicating a haploinsufficiency of Atbf1. The mPIN lesions expressed luminal cell markers and harbored molecular changes similar to those in human PIN and prostate cancer, including weaker expression of basal cell marker cytokeratin 5 (Ck5), cell adhesion protein E-cadherin, and the smooth muscle layer marker Sma; elevated expression of the oncoproteins phospho-Erk1/2, phospho-Akt and Muc1; and aberrant protein glycosylation. Gene expression profiling revealed a large number of genes that were dysregulated by Atbf1 deletion, particularly those that encode for secretory and cell membrane proteins. The four signaling networks that were most affected by Atbf1 deletion included those centered on Erk1/2 and IGF1, Akt and FSH, NF-?B and progesterone and ?-estradiol. These findings provide in vivo evidence that ATBF1 is a tumor suppressor in the prostate, suggest that loss of Atbf1 contributes to tumorigenesis by dysregulating membrane and secretory proteins and multiple signaling pathways, and provide a new animal model for prostate cancer. PMID:24934715

Sun, Xiaodong; Fu, Xiaoying; Li, Jie; Xing, Changsheng; Frierson, Henry F.; Wu, Hao; Ding, Xiaokun; Ju, Tongzhong; Cummings, Richard D.; Dong, Jin-Tang

2014-01-01

363

Placental gene-expression profiles of intrahepatic cholestasis of pregnancy reveal involvement of multiple molecular pathways in blood vessel formation and inflammation  

PubMed Central

Background Intrahepatic cholestasis of pregnancy (ICP) is a pregnancy-associated liver disease with potentially deleterious consequences for the fetus, particularly when maternal serum bile-acid concentration >40 ?M. However, the etiology and pathogenesis of ICP remain elusive. To reveal the underlying molecular mechanisms for the association of maternal serum bile-acid level and fetal outcome in ICP patients, DNA microarray was applied to characterize the whole-genome expression profiles of placentas from healthy women and women diagnosed with ICP. Methods Thirty pregnant women recruited in this study were categorized evenly into three groups: healthy group; mild ICP, with serum bile-acid concentration ranging from 10–40 ?M; and severe ICP, with bile-acid concentration >40 ?M. Gene Ontology analysis in combination with construction of gene-interaction and gene co-expression networks were applied to identify the core regulatory genes associated with ICP pathogenesis, which were further validated by quantitative real-time PCR and histological staining. Results The core regulatory genes were mainly involved in immune response, VEGF signaling pathway and G-protein-coupled receptor signaling, implying essential roles of immune response, vasculogenesis and angiogenesis in ICP pathogenesis. This implication was supported by the observed aggregated immune-cell infiltration and deficient blood vessel formation in ICP placentas. Conclusions Our study provides a system-level insight into the placental gene-expression profiles of women with mild or severe ICP, and reveals multiple molecular pathways in immune response and blood vessel formation that might contribute to ICP pathogenesis. PMID:25001852

2014-01-01

364

Multiple structural proteins are required for both transcriptional activation and negative autoregulation of Caulobacter crescentus flagellar genes.  

PubMed Central

The periodic and sequential expression of flagellar (fla) genes in the Caulobacter crescentus cell cycle depends on their organization into levels I to IV of a regulatory hierarchy in which genes at the top of the hierarchy are expressed early in the cell cycle and are required for the later expression of genes below them. In these studies, we have examined the regulatory role of level II fliF operon, which is located near the top of the hierarchy. The last gene in the fliF operon, flbD, encodes a transcriptional factor required for activation of sigma 54-dependent promoters at levels III and IV and negative autoregulation of the level II fliF promoter. We have physically mapped the fliF operon, identified four new genes in the transcription unit, and determined that the organization of these genes is 5'-fliF-fliG-flbE-fliN-flbD-3'. Three of the genes encode homologs of the MS ring protein (FliF) and two switch proteins (FliG and FliN) of enteric bacteria, and the fourth encodes a predicted protein (FlbE) without obvious similarities to known bacterial proteins. We have introduced nonpolar mutations in each of the open reading frames and shown that all of the newly identified genes (fliF, fliG, flbE, and fliN) are required in addition to flbD for activation of the sigma 54-dependent flgK and flbG promoters at level III. In contrast, fliF, fliG, and flbE, but not fliN, are required in addition to flbD for negative autoregulation of the level II fliF promoter. The simplest interpretation of these results is that the requirements of FlbD in transcriptional activation and repression are not identical, and we speculate that FlbD function is subject to dual or overlapping controls. We also discuss the requirement of multiple structural genes for regulation of levels II and III genes and suggest that fla gene expression in C. crescentus may be coupled to two checkpoints in flagellum assembly. Images PMID:8002583

Ramakrishnan, G; Zhao, J L; Newton, A

1994-01-01

365

MicroRNA-7 Inhibits Multiple Oncogenic Pathways to Suppress HER2?16 Mediated Breast Tumorigenesis and Reverse Trastuzumab Resistance  

PubMed Central

The oncogenic isoform of HER2, HER2?16, is expressed with HER2 in nearly 50% of HER2 positive breast tumors where HER2?16 drives metastasis and resistance to multiple therapeutic interventions including tamoxifen and trastuzumab. In recent years microRNAs have been shown to influence multiple aspects of tumorigenesis and tumor cell response to therapy. Accordingly, the HER2?16 oncogene alters microRNA expression to promote endocrine resistance. With the goal of identifying microRNA suppressors of HER2?16 oncogenic activity we investigated the contribution of altered microRNA expression to HER2?16 mediated tumorigenesis and trastuzumab resistance. Using a gene array strategy comparing microRNA expression profiles of MCF-7 to MCF-7/HER2?16 cells, we found that expression of HER2?16 significantly altered expression of 16 microRNAs by 2-fold or more including a 4.8 fold suppression of the miR-7 tumor suppressor. Reestablished expression of miR-7 in the MCF-7/HER2?16 cell line caused a G1 cell cycle arrest and reduced both colony formation and cell migration activity to levels of parental MCF-7 cells. Suppression of miR-7 in the MCF-7 cell line resulted in enhanced colony formation activity but not cell migration, indicating that miR-7 suppression is sufficient to drive tumor cell proliferation but not migration. MiR-7 inhibited MCF-7/HER2?16 cell migration through a mechanism involving suppression of the miR-7 target gene EGFR. In contrast, miR-7 inhibition of MCF-7/HER2?16 cell proliferation involved a pathway where miR-7 expression resulted in the inactivation of Src kinase independent of suppressed EGFR expression. Also independent of EGFR suppression, reestablished miR-7 expression sensitized refractory MCF-7/HER2?16 cells to trastuzumab. Our results demonstrate that reestablished miR-7 expression abolishes HER2?16 induced cell proliferation and migration while sensitizing HER2?16 expressing cells to trastuzumab therapy. We propose that miR-7 regulated pathways, including EGFR and Src kinase, represent targets for the therapeutic intervention of refractory and metastatic HER2?16 driven breast cancer. PMID:25532106

Huynh, Felicia C.; Jones, Frank E.

2014-01-01

366

Clathrin light chains are required for the gyrating-clathrin recycling pathway and thereby promote cell migration  

PubMed Central

The clathrin light chain (CLC) subunits participate in several membrane traffic pathways involving both clathrin and actin, through binding the actin-organizing huntingtin-interacting proteins (Hip). However, CLCs are dispensable for clathrin-mediated endocytosis of many cargoes. Here we observe that CLC depletion affects cell migration through Hip binding and reduces surface expression of ?1-integrin by interference with recycling following normal endocytosis of inactive ?1-integrin. CLC depletion and expression of a modified CLC also inhibit the appearance of gyrating (G)-clathrin structures, known mediators of rapid recycling of transferrin receptor from endosomes. Expression of the modified CLC reduces ?1-integrin and transferrin receptor recycling, as well as cell migration, implicating G-clathrin in these processes. Supporting a physiological role for CLC in migration, the CLCb isoform of CLC is upregulated in migratory human trophoblast cells during uterine invasion. Together, these studies establish CLCs as mediating clathrin–actin interactions needed for recycling by G-clathrin during migration. PMID:24852344

Majeed, Sophia R.; Vasudevan, Lavanya; Chen, Chih-Ying; Luo, Yi; Torres, Jorge A.; Evans, Timothy M.; Sharkey, Andrew; Foraker, Amy B.; Wong, Nicole M. L.; Esk, Christopher; Freeman, Theresa A.; Moffett, Ashley; Keen, James H.; Brodsky, Frances M.

2014-01-01

367

Activation of the Wnt/Planar Cell Polarity Pathway Is Required for Pericyte Recruitment during Pulmonary Angiogenesis.  

PubMed

Pericytes are perivascular cells localized to capillaries that promote vessel maturation, and their absence can contribute to vessel loss. Whether impaired endothelial-pericyte interaction contributes to small vessel loss in pulmonary arterial hypertension (PAH) is unclear. Using 3G5-specific, immunoglobulin G-coated magnetic beads, we isolated pericytes from the lungs of healthy subjects and PAH patients, followed by lineage validation. PAH pericytes seeded with healthy pulmonary microvascular endothelial cells failed to associate with endothelial tubes, resulting in smaller vascular networks compared to those with healthy pericytes. After the demonstration of abnormal polarization toward endothelium via live-imaging and wound-healing studies, we screened PAH pericytes for abnormalities in the Wnt/planar cell polarity (PCP) pathway, which has been shown to regulate cell motility and polarity in the pulmonary vasculature. PAH pericytes had reduced expression of frizzled 7 (Fzd7) and cdc42, genes crucial for Wnt/PCP activation. With simultaneous knockdown of Fzd7 and cdc42 in healthy pericytes in vitro and in a murine model of angiogenesis, motility and polarization toward pulmonary microvascular endothelial cells were reduced, whereas with restoration of both genes in PAH pericytes, endothelial-pericyte association was improved, with larger vascular networks. These studies suggest that the motility and polarity of pericytes during pulmonary angiogenesis are regulated by Wnt/PCP activation, which can be targeted to prevent vessel loss in PAH. PMID:25447046

Yuan, Ke; Orcholski, Mark E; Panaroni, Cristina; Shuffle, Eric M; Huang, Ngan F; Jiang, Xinguo; Tian, Wen; Vladar, Eszter K; Wang, Lingli; Nicolls, Mark R; Wu, Joy Y; de Jesus Perez, Vinicio A

2015-01-01

368

1–42 ?-Amyloid peptide requires PDK1/nPKC/Rac 1 pathway to induce neuronal death  

PubMed Central

1–42 ?-Amyloid (A?1–42) peptide is a key molecule involved in the development of Alzheimer's disease. Some of its effects are manifested at the neuronal morphological level. These morphological changes involve loss of neurites due to cytoskeleton alterations. However, the mechanism of A?1–42 peptide activation of the neurodegenerative program is still poorly understood. Here, A?1–42 peptide-induced transduction of cellular death signals through the phosphatidylinositol 3-kinase (PI3K)/phosphoinositol-dependent kinase (PDK)/novel protein kinase C (nPKC)/Rac 1 axis is described. Furthermore, pharmacological inhibition of PDK1 and nPKC activities blocks Rac 1 activation and neuronal cell death. Our results provide insights into an unsuspected connection between PDK1, nPKCs and Rac 1 in the same signal-transduction pathway and points out nPKCs and Rac 1 as potential therapeutic targets to block the toxic effects of A?1–42 peptide in neurons. PMID:23340502

Manterola, L; Hernando-Rodríguez, M; Ruiz, A; Apraiz, A; Arrizabalaga, O; Vellón, L; Alberdi, E; Cavaliere, F; Lacerda, H M; Jimenez, S; Parada, L A; Matute, C; Zugaza, J L

2013-01-01

369

The ubiquitin-dependent targeting pathway in Saccharomyces cerevisiae plays a critical role in multiple chromatin assembly regulatory steps.  

PubMed Central

In a screen designed to isolate Saccharomyces cerevisiae strains defective for in vitro chromatin assembly, two temperature-sensitive (ts) mutants were obtained: rmc1 and rmc3 (remodeling of chromatin). Cloning of RMC1 and RMC3 revealed a broad role for the ubiquitin-dependent targeting cascade as the ubiquitin-protein ligases (E3s), the anaphase promoting complex (APC; RMC1 encodes APC5) and Rsp5p, respectively, were identified. Genetic studies linked the rmc1/apc5 chromatin assembly defect to APC function: rmc1/apc5 genetically interacted with apc9Delta, apc10Delta, and cdc26Delta mutants. Furthermore, phenotypes associated with the rmc1/apc5 allele were consistent with defects in chromatin metabolism and in APC function: (i) UV sensitivity, (ii) plasmid loss, (iii) accumulation of G2/M cells, and (iv) suppression of the ts defect by growth on glucose-free media and by expression of ubiquitin. On the other hand, the multifunctional E3, Rsp5p, was shown to be required for both in vitro and in vivo chromatin assembly, as well as for the proper transcriptional and translational control of at least histone H3. The finding that the distinctly different E3 enzymes, APC and Rsp5p, both play roles in regulating chromatin assembly highlight the depth of the regulatory networks at play. The significance of these findings will be discussed. PMID:12399376

Harkness, Troy A A; Davies, Gerald F; Ramaswamy, Vijay; Arnason, Terra G

2002-01-01

370

Gibberellic acid nitrite stimulates germination of two species of light-requiring seeds via the nitric oxide pathway.  

PubMed

We used two species of light-requiring seeds, Paulownia tomentosa, which have absolute light requirement (no germination in darkness), and Stellaria media seeds, which germinate in darkness to a certain extent because of presence of preformed active phytochrome, to obtain results strongly suggesting that gibberellic acid nitrite stimulates seed germination via its capability as a functional NO donor. Exogenous application of gibberellic acid nitrite stimulates gibberellin-insensitive Stellaria media seed germination in darkness as do a wide variety of NO donors. Pure gibberellic acid could replace the light requirement of P. tomentosa seeds, thus enabling them to germinate in darkness. Gibberellic acid nitrite did not have this effect. A stimulative effect from gibberellic acid nitrite could be detected only after exposure of these seeds to short, 10 min, pulse of red light. Taken together, these results suggest that gibberellic activity of gibberellic acid nitrite is lost after nitrosation but, regarding to the presence of -O-NO moiety in the molecule, gibberellic acid nitrite shares stimulative properties in seed germination with other compounds with NO-releasing properties. PMID:16154981

Jovanovi?, Vladan; Giba, Zlatko; Djokovi?, Dejan; Milosavljevi?, Slobodan; Grubisi?, Dragoljub; Konjevi?, Radomir

2005-06-01

371

Targeting NAD+ salvage pathway induces autophagy in multiple myeloma cells via mTORC1 and extracellular signal-regulated kinase (ERK1/2) inhibition.  

PubMed

Malignant cells have a higher nicotinamide adenine dinucleotide (NAD(+)) turnover rate than normal cells, making this biosynthetic pathway an attractive target for cancer treatment. Here we investigated the biologic role of a rate-limiting enzyme involved in NAD(+) synthesis, Nampt, in multiple myeloma (MM). Nampt-specific chemical inhibitor FK866 triggered cytotoxicity in MM cell lines and patient MM cells, but not normal donor as well as MM patients PBMCs. Importantly, FK866 in a dose-dependent fashion triggered cytotoxicity in MM cells resistant to conventional and novel anti-MM therapies and overcomes the protective effects of cytokines (IL-6, IGF-1) and bone marrow stromal cells. Nampt knockdown by RNAi confirmed its pivotal role in maintenance of both MM cell viability and intracellular NAD(+) stores. Interestingly, cytotoxicity of FK866 triggered autophagy, but not apoptosis. A transcriptional-dependent (TFEB) and independent (PI3K/mTORC1) activation of autophagy mediated FK866 MM cytotoxicity. Finally, FK866 demonstrated significant anti-MM activity in a xenograft-murine MM model, associated with down-regulation of ERK1/2 phosphorylation and proteolytic cleavage of LC3 in tumor cells. Our data therefore define a key role of Nampt in MM biology, providing the basis for a novel targeted therapeutic approach. PMID:22955917

Cea, Michele; Cagnetta, Antonia; Fulciniti, Mariateresa; Tai, Yu-Tzu; Hideshima, Teru; Chauhan, Dharminder; Roccaro, Aldo; Sacco, Antonio; Calimeri, Teresa; Cottini, Francesca; Jakubikova, Jana; Kong, Sun-Young; Patrone, Franco; Nencioni, Alessio; Gobbi, Marco; Richardson, Paul; Munshi, Nikhil; Anderson, Kenneth C

2012-10-25

372

Perifosine inhibits lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-? production via regulation multiple signaling pathways: new implication for Kawasaki disease (KD) treatment.  

PubMed

Kawasaki disease (KD) is a multisystem vasculitis of unknown etiology, with coronary artery aneurysms occurring in majority of untreated cases. Tumor necrosis factor (TNF)-? is the pleiotropic inflammatory cytokine elevated during the acute phase of KD, which induces damage to vascular endothelial cells to cause systemic vasculitis. We here investigated the potential role of perifosine, a novel Akt inhibitor, on TNF? expression in LPS-stimulated macrophages and in ex-vivo cultured peripheral blood mononuclear cells (PBMCs) of acute KD patients. Here, we found that perifosine inhibited LPS-induced TNF? expression and production in mouse macrophages (RAW 264.7 cells and bone marrow-derived macrophages (BMDMs)). Meanwhile, perifosine administration down-regulated TNF? production in PBMCs isolated from acute KD patients. For the mechanism study, we found that perifosine significantly inhibited Akt and ERK/mitogen-activated protein kinases (MAPK) signaling, while activating AMP-activated protein kinase (AMPK) signaling in both patients' PBMCs and LPS-stimulated macrophages. Interestingly, although perifosine is generally known as an Akt inhibitor, our data suggested that ERK inhibition and AMPK activation, but not Akt inactivation were possibly involved in perifosine-mediated inhibition against TNF? production in monocytes. In conclusion, our data suggested that perifosine significantly inhibited TNF? production via regulation multiple signaling pathways. The results of this study should have significant translational relevance in managing this devastating disease. PMID:23806687

Shen, Jie; Liang, Li; Wang, Chunlin

2013-07-26

373

Cocaine Potentiates Multiple 5-HT2A Receptor Signaling Pathways and Is Associated with Decreased Phosphorylation of 5-HT2A Receptors In Vivo.  

PubMed

Cocaine addiction is a chronic relapsing disorder in which the underlying mechanisms are not well understood. Here, we used Sprague-Dawley rats injected with either saline (1 ml/kg) or cocaine (15 mg/kg) for 7 days (b.i.d, i.p) to study the effect of cocaine on several components of 5-HT2A receptor signaling in prefrontal cortex (PFCx). We detected enhanced activation of 5-HT2A receptor-mediated phospholipase C beta (PLC?) and extracellular regulated kinase 1/2 activity in PFCx of cocaine-treated rats. Although we were unable to detect changes in the protein levels of several proteins associated with 5-HT2A receptor signaling such as caveolin-1, postsynaptic density protein 95, ?-arrestin 2, etc., we found a significant reduction in the phosphorylation status of cortical 5-HT2A receptors. This phenomenon was associated with reduced levels of G-protein receptor kinase 5 (GRK5), but not GRK2 or RSK2, proteins. Our results suggest that decreased phosphorylation of 5-HT2A receptors could mediate, at least in part, the cocaine-induced potentiation of multiple 5-HT2A receptor signaling pathways in rat PFCx. As discussed in this manuscript, we hypothesize that preventing these neuroadaptations in 5-HT2A receptor signaling may alleviate some of the aversive withdrawal-associated symptoms that contribute to relapse to cocaine abuse. PMID:25213649

Franklin, Jade M; Carrasco, Gonzalo A

2015-03-01

374

TRIM13 (RFP2) downregulation decreases tumour cell growth in multiple myeloma through inhibition of NF Kappa B pathway and proteasome activity  

PubMed Central

Multiple myeloma (MM) is an incurable neoplasm caused by proliferation of malignant plasma cells in the bone marrow (BM). MM is characterized frequently by a complete or partial deletion of chromosome 13q14, seen in more than 50% of patients at diagnosis. Within this deleted region the tripartite motif containing 13 (TRIM13, also termed RFP2) gene product has been proposed to be a tumour suppressor gene (TSG). Here, we show that low expression levels of TRIM13 in MM are associated with chromosome 13q deletion and poor clinical outcome. We present a functional analysis of TRIM13 using a loss-of-function approach, and demonstrate that TRIM13 downregulation decreases tumour cell survival as well as cell cycle progression and proliferation of MM cells. In addition, we provide evidence for the involvement of TRIM13 downregulation in inhibiting the NF kappa B pathway and the activity of the 20S proteasome. Although this data does not support a role of TRIM13 as a TSG, it substantiates important roles of TRIM13 in MM tumour survival and proliferation, underscoring its potential role as a novel target for therapeutic intervention. PMID:23647456

Gatt, Moshe E; Takada, Kohichi; Mani, Mala; Lerner, Mikael; Pick, Marjorie; Hideshima, Teru; Carrasco, Daniel E.; Protopopov, Alexei; Ivanova, Elena; Sangfelt, Olle; Grandér, Dan; Barlogie, Bart; Shaughnessy, John D.; Anderson, Kenneth C.; Carrasco, Daniel R.

2013-01-01

375

Fungal communication requires the MAK-2 pathway elements STE-20 and RAS-2, the NRC-1 adapter STE-50 and the MAP kinase scaffold HAM-5.  

PubMed

Intercellular communication is critical for the survival of unicellular organisms as well as for the development and function of multicellular tissues. Cell-to-cell signaling is also required to develop the interconnected mycelial network characteristic of filamentous fungi and is a prerequisite for symbiotic and pathogenic host colonization achieved by molds. Somatic cell-cell communication and subsequent cell fusion is governed by the MAK-2 mitogen activated protein kinase (MAPK) cascade in the filamentous ascomycete model Neurospora crassa, yet the composition and mode of regulation of the MAK-2 pathway are currently unclear. In order to identify additional components involved in MAK-2 signaling we performed affinity purification experiments coupled to mass spectrometry with strains expressing functional GFP-fusion proteins of the MAPK cascade. This approach identified STE-50 as a regulatory subunit of the Ste11p homolog NRC-1 and HAM-5 as cell-communication-specific scaffold protein of the MAPK cascade. Moreover, we defined a network of proteins consisting of two Ste20-related kinases, the small GTPase RAS-2 and the adenylate cyclase capping protein CAP-1 that function upstream of the MAK-2 pathway and whose signals converge on the NRC-1/STE-50 MAP3K complex and the HAM-5 scaffold. Finally, our data suggest an involvement of the striatin interacting phosphatase and kinase (STRIPAK) complex, the casein kinase 2 heterodimer, the phospholipid flippase modulators YPK-1 and NRC-2 and motor protein-dependent vesicle trafficking in the regulation of MAK-2 pathway activity and function. Taken together, these data will have significant implications for our mechanistic understanding of MAPK signaling and for homotypic cell-cell communication in fungi and higher eukaryotes. PMID:25411845

Dettmann, Anne; Heilig, Yvonne; Valerius, Oliver; Ludwig, Sarah; Seiler, Stephan

2014-11-01

376

MoeA, an enzyme in the molybdopterin synthesis pathway, is required for rifamycin SV production in Amycolatopsis mediterranei U32.  

PubMed

Rifamycin SV contains one amide nitrogen atom at its C(7)N moiety. Earlier labeling studies suggested that nitrogen might be incorporated from a pathway involved in a molybdenum-dependent nitrate reductase. However, no genetic evidence is available thus far. The structural gene moeA, which is involved in molybdopterin synthesis in various organisms, has been cloned from rifamycin SV-producing Amycolatopsis mediterranei strain