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Sample records for pathways regulate tnf-a

  1. METABOLIC PATHWAY REGULATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Research efforts in the past two decades have revealed the complex mechanisms employed by fungi to control gene activity. The tremendous expansion in our knowledge of the regulation of nitrogen metabolism and carbon metabolism, due largely to the powerful combination of genetics, biochemistry, and ...

  2. Mechanisms of Hippo pathway regulation.

    PubMed

    Meng, Zhipeng; Moroishi, Toshiro; Guan, Kun-Liang

    2016-01-01

    The Hippo pathway was initially identified in Drosophila melanogaster screens for tissue growth two decades ago and has been a subject extensively studied in both Drosophila and mammals in the last several years. The core of the Hippo pathway consists of a kinase cascade, transcription coactivators, and DNA-binding partners. Recent studies have expanded the Hippo pathway as a complex signaling network with >30 components. This pathway is regulated by intrinsic cell machineries, such as cell-cell contact, cell polarity, and actin cytoskeleton, as well as a wide range of signals, including cellular energy status, mechanical cues, and hormonal signals that act through G-protein-coupled receptors. The major functions of the Hippo pathway have been defined to restrict tissue growth in adults and modulate cell proliferation, differentiation, and migration in developing organs. Furthermore, dysregulation of the Hippo pathway leads to aberrant cell growth and neoplasia. In this review, we focus on recent developments in our understanding of the molecular actions of the core Hippo kinase cascade and discuss key open questions in the regulation and function of the Hippo pathway. PMID:26728553

  3. Mechanisms of Hippo pathway regulation

    PubMed Central

    Meng, Zhipeng; Moroishi, Toshiro; Guan, Kun-Liang

    2016-01-01

    The Hippo pathway was initially identified in Drosophila melanogaster screens for tissue growth two decades ago and has been a subject extensively studied in both Drosophila and mammals in the last several years. The core of the Hippo pathway consists of a kinase cascade, transcription coactivators, and DNA-binding partners. Recent studies have expanded the Hippo pathway as a complex signaling network with >30 components. This pathway is regulated by intrinsic cell machineries, such as cell–cell contact, cell polarity, and actin cytoskeleton, as well as a wide range of signals, including cellular energy status, mechanical cues, and hormonal signals that act through G-protein-coupled receptors. The major functions of the Hippo pathway have been defined to restrict tissue growth in adults and modulate cell proliferation, differentiation, and migration in developing organs. Furthermore, dysregulation of the Hippo pathway leads to aberrant cell growth and neoplasia. In this review, we focus on recent developments in our understanding of the molecular actions of the core Hippo kinase cascade and discuss key open questions in the regulation and function of the Hippo pathway. PMID:26728553

  4. Multiple pathways regulate shoot branching

    PubMed Central

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

    2015-01-01

    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

  5. Methylerythritol 4-phosphate (MEP) pathway metabolic regulation.

    PubMed

    Banerjee, A; Sharkey, T D

    2014-08-01

    Covering: up to February 2014. The methylerythritol 4-phosphate (MEP) pathway is the recently discovered source of isoprenoid precursors isopentenyl diphosphate (IDP) and dimethylallyl diphosphate (DMADP) in most bacteria, some eukaryotic parasites, and the plastids of plant cells. The precursors lead to the formation of various isoprenoids having diverse roles in different biological processes. Some isoprenoids have important commercial uses. Isoprene, which is made in surprising abundance by some trees, plays a significant role in atmospheric chemistry. The genetic regulation of this pathway has been discussed but information about metabolic regulation is just now becoming available. This review covers metabolic regulation of the MEP pathway starting from the inputs of carbon, ATP, and reducing power. A number of different regulatory mechanisms involving intermediate metabolites and/or enzymes are discussed. Some recent data indicate that methylerythritol cyclodiphosphate (MEcDP), the fifth intermediate of this pathway, is a key metabolite. It has been found to play diverse roles in regulation within the pathway as well as coordinating other biological processes by acting as a stress regulator in bacteria and possibly a retrograde signal from plastids to the nucleus in plants. In this review we focus on the role of the MEP pathway in photosynthetic leaves during isoprene emission and more generally the metabolic regulation of the MEP pathway in both plants and bacteria. PMID:24921065

  6. Plant phytotoxicity: A self-regulating pathway

    SciTech Connect

    Not Available

    1989-07-01

    During the session on regulating sludge utilization, held at BioCycle's 19th Annual National conference on Composting and Recycling, a participant asked one of the speakers, Dr. Alan Rubin of the US EPA's Office of Water Regulations and Standards, why the plant phytotoxicity pathway should be the most limiting, especially when there is no concern about human or animal health. The question related specifically to copper being the most limiting metal concentration limit for many sludge composting and land application programs under the proposed Part 503 regulations. And the most limiting pathway for copper is Pathway 7, sludge-soil-plant phytotoxicity. Rubin responded that the regulation is supposed to protect both human health and the environment, e.g. plants and animals other than humans.

  7. Hippo pathway regulation of gastrointestinal tissues.

    PubMed

    Yu, Fa-Xing; Meng, Zhipeng; Plouffe, Steven W; Guan, Kun-Liang

    2015-01-01

    The Hippo pathway plays a crucial role in regulating tissue homeostasis and organ size, and its deregulation is frequently observed in human cancer. Yap is the major effector of and is inhibited by the Hippo pathway. In mouse model studies, inducible Yap expression in multiple tissues results in organ overgrowth. In the liver, knockout of upstream Hippo pathway components or transgenic expression of Yap leads to liver enlargement and hepatocellular carcinoma. In the small intestine or colon, deletion of upstream Hippo pathway components also results in expansion of intestinal progenitor cells and eventual development of adenomas. Genetic deletion of Yap in the intestine does not change the intestinal structure, but Yap is essential for intestinal repair upon certain types of tissue injury. The function of the Hippo pathway has also been studied in other gastrointestinal tissues, including the pancreas and stomach. Here we provide a brief overview of the Hippo pathway and discuss the physiological and pathological functions of this tumor suppressor pathway in gastrointestinal tissues. PMID:25293527

  8. Crosstalk among Epigenetic Pathways Regulates Neurogenesis

    PubMed Central

    Jobe, Emily M.; McQuate, Andrea L.; Zhao, Xinyu

    2012-01-01

    The process of neurogenesis includes neural stem cell proliferation, fate specification, young neuron migration, neuronal maturation, and functional integration into existing circuits. Although neurogenesis occurs largely during embryonic development, low levels but functionally important neurogenesis persists in restricted regions of the postnatal brain, including the subgranular zone of the dentate gyrus in the hippocampus and the subventricular zone of the lateral ventricles. This review will cover both embryonic and adult neurogenesis with an emphasis on the latter. Of the many endogenous mediators of postnatal neurogenesis, epigenetic pathways, such as mediators of DNA methylation, chromatin remodeling systems, and non-coding RNA modulators, appear to play an integral role. Mounting evidence shows that such epigenetic factors form regulatory networks, which govern each step of postnatal neurogenesis. In this review, we explore the emerging roles of epigenetic mechanisms particularly microRNAs, element-1 silencing transcription factor/neuron-restrictive silencing factor (REST/NRSF), polycomb proteins, and methyl-CpG bindings proteins, in regulating the entire process of postnatal and adult neurogenesis. We further summarize recent data regarding how the crosstalk among these different epigenetic proteins forms the critical regulatory network that regulates neuronal development. We finally discuss how crosstalk between these pathways may serve to translate environmental cues into control of the neurogenic process. PMID:22586361

  9. Wnt pathway regulation of intestinal stem cells.

    PubMed

    Mah, Amanda T; Yan, Kelley S; Kuo, Calvin J

    2016-09-01

    Wnt signalling is involved in multiple aspects of embryonic development and adult tissue homeostasis, notably via controlling cellular proliferation and differentiation. Wnt signalling is subject to stringent positive and negative regulation to promote proper development and homeostasis yet avoid aberrant growth. Such multi-layer regulation includes post-translational modification and processing of Wnt proteins themselves, R-spondin (Rspo) amplification of Wnt signalling, diverse receptor families, and intracellular and extracellular antagonists and destruction and transcription complexes. In the gastrointestinal tract, Wnt signalling is crucial for development and renewal of the intestinal epithelium. Intestinal stem cells (ISCs) undergo symmetric division and neutral drift dynamics to renew the intestinal epithelium. Sources of Wnts and Wnt amplifers such as R-spondins are beginning to be elucidated as well as their functional contribution to intestinal homeostasis. In this review we focus on regulation of ISCs and intestinal homeostasis by the Wnt/Rspo pathway, the potential cellular sources of Wnt signalling regulators and highlight potential future areas of study. PMID:27581568

  10. [Pathways of flowering regulation in plants].

    PubMed

    Liu, Yongping; Yang, Jing; Yang, Mingfeng

    2015-11-01

    Flowering, the floral transition from vegetative growth to reproductive growth, is induced by diverse endogenous and exogenous cues, such as photoperiod, temperature, hormones and age. Precise flowering time is critical to plant growth and evolution of species. The numerous renewal molecular and genetic results have revealed five flowering time pathways, including classical photoperiod pathway, vernalization pathway, autonomous pathway, gibberellins (GA) pathway and newly identified age pathway. These pathways take on relatively independent role, and involve extensive crosstalks and feedback loops. This review describes the complicated regulatory network of this floral transition to understand the molecular mechanism of flowering and provide references for further research in more plants. PMID:26939439

  11. Global Regulation of a Differentiation MAPK Pathway in Yeast

    PubMed Central

    Chavel, Colin A.; Caccamise, Lauren M.; Li, Boyang; Cullen, Paul J.

    2014-01-01

    Cell differentiation requires different pathways to act in concert to produce a specialized cell type. The budding yeast Saccharomyces cerevisiae undergoes filamentous growth in response to nutrient limitation. Differentiation to the filamentous cell type requires multiple signaling pathways, including a mitogen-activated protein kinase (MAPK) pathway. To identify new regulators of the filamentous growth MAPK pathway, a genetic screen was performed with a collection of 4072 nonessential deletion mutants constructed in the filamentous (Σ1278b) strain background. The screen, in combination with directed gene-deletion analysis, uncovered 97 new regulators of the filamentous growth MAPK pathway comprising 40% of the major regulators of filamentous growth. Functional classification extended known connections to the pathway and identified new connections. One function for the extensive regulatory network was to adjust the activity of the filamentous growth MAPK pathway to the activity of other pathways that regulate the response. In support of this idea, an unregulated filamentous growth MAPK pathway led to an uncoordinated response. Many of the pathways that regulate filamentous growth also regulated each other’s targets, which brings to light an integrated signaling network that regulates the differentiation response. The regulatory network characterized here provides a template for understanding MAPK-dependent differentiation that may extend to other systems, including fungal pathogens and metazoans. PMID:25189875

  12. Master Regulators, Regulatory Networks, and Pathways of Glioblastoma Subtypes

    PubMed Central

    Bozdag, Serdar; Li, Aiguo; Baysan, Mehmet; Fine, Howard A

    2014-01-01

    Glioblastoma multiforme (GBM) is the most common malignant brain tumor. GBM samples are classified into subtypes based on their transcriptomic and epigenetic profiles. Despite numerous studies to better characterize GBM biology, a comprehensive study to identify GBM subtype- specific master regulators, gene regulatory networks, and pathways is missing. Here, we used FastMEDUSA to compute master regulators and gene regulatory networks for each GBM subtype. We also ran Gene Set Enrichment Analysis and Ingenuity Pathway Analysis on GBM expression dataset from The Cancer Genome Atlas Project to compute GBM- and GBM subtype-specific pathways. Our analysis was able to recover some of the known master regulators and pathways in GBM as well as some putative novel regulators and pathways, which will aide in our understanding of the unique biology of GBM subtypes. PMID:25368508

  13. Function and Regulation in MAPK Signaling Pathways

    PubMed Central

    Chen, Raymond E.; Thorner, Jeremy

    2007-01-01

    Signaling pathways that activate different mitogen-activated protein kinases (MAPKs) elicit many of the responses that are evoked in cells by changes in certain environmental conditions and upon exposure to a variety of hormonal and other stimuli. These pathways were first elucidated in the unicellular eukaryote Saccharomyces cerevisiae (budding yeast). Studies of MAPK pathways in this organism continue to be especially informative in revealing the molecular mechanisms by which MAPK cascades operate, propagate signals, modulate cellular processes, and are controlled by regulatory factors both internal to and external to the pathways. Here we highlight recent advances and new insights about MAPK-based signaling that have been made through studies in yeast, which provide lessons directly applicable to, and that enhance our understanding of, MAPK-mediated signaling in mammalian cells. PMID:17604854

  14. Oscillatory Dynamics of the Extracellular Signal-regulated Kinase Pathway

    SciTech Connect

    Shankaran, Harish; Wiley, H. S.

    2010-12-01

    The extracellular signal-regulated kinase (ERK) pathway is a central signaling pathway in development and disease and is regulated by multiple negative and positive feedback loops. Recent studies have shown negative feedback from ERK to upstream regulators can give rise to biochemical oscillations with a periodicity of between 15-30 minutes. Feedback due to the stimulated transcription of negative regulators of the ERK pathway can also give rise to transcriptional oscillations with a periodicity of 1-2h. The biological significance of these oscillations is not clear, but recent evidence suggests that transcriptional oscillations participate in developmental processes, such as somite formation. Biochemical oscillations are more enigmatic, but could provide a mechanism for encoding different types of inputs into a common signaling pathway.

  15. Regulation of the gibberellin pathway by auxin and DELLA proteins.

    PubMed

    O'Neill, Damian P; Davidson, Sandra E; Clarke, Victoria C; Yamauchi, Yukika; Yamaguchi, Shinjiro; Kamiya, Yuji; Reid, James B; Ross, John J

    2010-10-01

    The synthesis and deactivation of bioactive gibberellins (GA) are regulated by auxin and by GA signalling. The effect of GA on its own pathway is mediated by DELLA proteins. Like auxin, the DELLAs promote GA synthesis and inhibit its deactivation. Here, we investigate the relationships between auxin and DELLA regulation of the GA pathway in stems, using a pea double mutant that is deficient in DELLA proteins. In general terms our results demonstrate that auxin and DELLAs independently regulate the GA pathway, contrary to some previous suggestions. The extent to which DELLA regulation was able to counteract the effects of auxin regulation varied from gene to gene. For Mendel's LE gene (PsGA3ox1) no counteraction was observed. However, for another synthesis gene, a GA 20-oxidase, the effect of auxin was weak and in WT plants appeared to be completely over-ridden by DELLA regulation. For a key GA deactivation (2-oxidase) gene, PsGA2ox1, the up-regulation induced by auxin deficiency was reduced to some extent by DELLA regulation. A second pea 2-oxidase gene, PsGA2ox2, was up-regulated by auxin, in a DELLA-independent manner. In Arabidopsis also, one 2-oxidase gene was down-regulated by auxin while another was up-regulated. Monitoring the metabolism pattern of GA(20) showed that in Arabidopsis, as in pea, auxin can promote the accumulation of bioactive GA. PMID:20706734

  16. Mevalonate Pathway Regulates Cell Size Homeostasis and Proteostasis through Autophagy

    PubMed Central

    Miettinen, Teemu P.; Björklund, Mikael

    2015-01-01

    Summary Balance between cell growth and proliferation determines cell size homeostasis, but little is known about how metabolic pathways are involved in the maintenance of this balance. Here, we perform a screen with a library of clinically used drug molecules for their effects on cell size. We find that statins, inhibitors of the mevalonate pathway, reduce cell proliferation and increase cell size and cellular protein density in various cell types, including primary human cells. Mevalonate pathway effects on cell size and protein density are mediated through geranylgeranylation of the small GTPase RAB11, which is required for basal autophagic flux. Our results identify the mevalonate pathway as a metabolic regulator of autophagy and expose a paradox in the regulation of cell size and proteostasis, where inhibition of an anabolic pathway can cause an increase in cell size and cellular protein density. PMID:26686643

  17. Chloride Regulation in the Pain Pathway

    PubMed Central

    Price, Theodore J; Cervero, Fernando; Gold, Michael S; Hammond, Donna L; Prescott, Steven A

    2009-01-01

    Melzack and Wall’s Gate Control Theory of Pain laid the theoretical groundwork for a role of spinal inhibition in endogenous pain control. While the Gate Control Theory was based on the notion that spinal inhibition is dynamically regulated, mechanisms underlying the regulation of inhibition have turned out to be far more complex than Melzack and Wall could have ever imagined. Recent evidence indicates that an exquisitely sensitive form of regulation involves changes in anion equilibrium potential (Eanion), which subsequently impacts fast synaptic inhibition mediated GABAA, and to a lesser extent, glycine receptor activation, the prototypic ligand gated anion channels. The cation-chloride co-transporters (in particular NKCC1 and KCC2) have emerged as proteins that play a critical role in the dynamic regulation of Eanion which in turn appears to play a critical role in hyperalgesia and allodynia following peripheral inflammation or nerve injury. This review summarizes the current state of knowledge in this area with particular attention to how such findings relate to endogenous mechanisms of hyperalgesia and allodynia and potential applications for therapeutics based on modulation of intracellular Cl− gradients or pharmacological interventions targeting GABAA receptors PMID:19167425

  18. Mechanical Regulation of Signaling Pathways in Bone

    PubMed Central

    Thompson, William R.; Rubin, Clinton T.; Rubin, Janet

    2012-01-01

    A wide range of cell types depend on mechanically induced signals to enable appropriate physiological responses. The skeleton is particularly dependent on mechanical information to guide the resident cell population towards adaptation, maintenance and repair. Research at the organ, tissue, cell and molecular levels has improved our understanding of how the skeleton can recognize the functional environment, and how these challenges are translated into cellular information that can site-specifically alter phenotype. This review first considers those cells within the skeleton that are responsive to mechanical signals, including osteoblasts, osteoclasts, osteocytes and osteoprogenitors. This is discussed in light of a range of experimental approaches that can vary parameters such as strain, fluid shear stress, and pressure. The identity of mechanoreceptor candidates is approached, with consideration of integrins, pericellular tethers, focal adhesions, ion channels, cadherins, connexins, and the plasma membrane including caveolar and non-caveolar lipid rafts and their influence on integral signaling protein interactions. Several mechanically regulated intracellular signaling cascades are detailed including activation of kinases (Akt, MAPK, FAK), β-catenin, GTPases, and calcium signaling events. While the interaction of bone cells with their mechanical environment is complex, an understanding of mechanical regulation of bone signaling is crucial to understanding bone physiology, the etiology of diseases such as osteoporosis, and to the development of interventions to improve bone strength. PMID:22575727

  19. Neurotrophin signalling pathways regulating neuronal apoptosis.

    PubMed

    Miller, F D; Kaplan, D R

    2001-07-01

    Recent evidence indicates that naturally occurring neuronal death in mammals is regulated by the interplay between receptor-mediated prosurvival and proapoptotic signals. The neurotrophins, a family of growth factors best known for their positive effects on neuronal biology, have now been shown to mediate both positive and negative survival signals, by signalling through the Trk and p75 neurotrophin receptors, respectively. The mechanisms whereby these two neurotrophin receptors interact to determine neuronal survival have been difficult to decipher, largely because both can signal independently or coincidentally, depending upon the cell or developmental context. Nonetheless, the past several years have seen significant advances in our understanding of this receptor signalling system. In this review, we focus on the proapoptotic actions of the p75 neurotrophin receptor (p75NTR), and on the interplay between Trk and p75NTR that determines neuronal survival. PMID:11529497

  20. Regulators in the apoptotic pathway during spermatogenesis: Killers or guards?

    PubMed

    Xu, Ya-Ru; Dong, Hong-Shan; Yang, Wan-Xi

    2016-05-15

    Apoptosis occurs at any time in the ontogeny of the testis, especially during the first wave of spermatogenesis. However, the exact mechanisms by which homeostasis of apoptosis and survival in GCs and mature sperm are orchestrated remain unclear. Three pathways during the process of apoptosis in mammals are discussed extensively. The three pathways are extrinsic pathway, mitochondrial pathway and endoplasmic reticulum pathway. Based on that, many factors, such as growth factors (SCF, FGF, TGF), hormones (FSH, LH, E2, MIS), partial oxygen pressure, and testis specific genes are involved in apoptosis and survival process. The pathways of apoptosis adopted by the GCs and sperm depend on the types of stimuli they receive. Diverse pathways are initiated in heat-stress induced apoptosis of GCs and the destiny of GCs suppressed by hyperglycemia is mainly regulated by a rheostat of total oxidants and anti-oxidants which leading to intrinsic pathway. In this review, we provide an overview of three classic pathways and important factors involved in the process of germ cell apoptosis and survival, and discuss the recent advances made in understanding of the molecular mechanisms of spermatogenic cells and sperm response to stress-inducers, such as heat stress and hyperglycemia. All the findings may provide clues to the control of male fertility or treating germ cell tumors and other testis associated pathological conditions, at the same time, a novel idea may result in devising much safer contraception with high efficiency. PMID:26861610

  1. The N-end rule pathway and regulation by proteolysis

    PubMed Central

    Varshavsky, Alexander

    2011-01-01

    The N-end rule relates the regulation of the in vivo half-life of a protein to the identity of its N-terminal residue. Degradation signals (degrons) that are targeted by the N-end rule pathway include a set called N-degrons. The main determinant of an N-degron is a destabilizing N-terminal residue of a protein. In eukaryotes, the N-end rule pathway is a part of the ubiquitin system and consists of two branches, the Ac/N-end rule and the Arg/N-end rule pathways. The Ac/N-end rule pathway targets proteins containing Nα-terminally acetylated (Nt-acetylated) residues. The Arg/N-end rule pathway recognizes unacetylated N-terminal residues and involves N-terminal arginylation. Together, these branches target for degradation a majority of cellular proteins. For example, more than 80% of human proteins are cotranslationally Nt-acetylated. Thus, most proteins harbor a specific degradation signal, termed AcN-degron, from the moment of their birth. Specific N-end rule pathways are also present in prokaryotes and in mitochondria. Enzymes that produce N-degrons include methionine-aminopeptidases, caspases, calpains, Nt-acetylases, Nt-amidases, arginyl-transferases, and leucyl-transferases. Regulated degradation of specific proteins by the N-end rule pathway mediates a legion of physiological functions, including the sensing of heme, oxygen, and nitric oxide; selective elimination of misfolded proteins; the regulation of DNA repair, segregation, and condensation; the signaling by G proteins; the regulation of peptide import, fat metabolism, viral and bacterial infections, apoptosis, meiosis, spermatogenesis, neurogenesis, and cardiovascular development; and the functioning of adult organs, including the pancreas and the brain. Discovered 25 years ago, this pathway continues to be a fount of biological insights. PMID:21633985

  2. The Hippo-Salvador signaling pathway regulates renal tubulointerstitial fibrosis

    PubMed Central

    Seo, Eunjeong; Kim, Wan-Young; Hur, Jeongmi; Kim, Hanbyul; Nam, Sun Ah; Choi, Arum; Kim, Yu-Mi; Park, Sang Hee; Chung, Chaeuk; Kim, Jin; Min, Soohong; Myung, Seung-Jae; Lim, Dae-Sik; Kim, Yong Kyun

    2016-01-01

    Renal tubulointerstitial fibrosis (TIF) is the final pathway of various renal injuries that result in chronic kidney disease. The mammalian Hippo-Salvador signaling pathway has been implicated in the regulation of cell proliferation, cell death, tissue regeneration, and tumorigenesis. Here, we report that the Hippo-Salvador pathway plays a role in disease development in patients with TIF and in a mouse model of TIF. Mice with tubular epithelial cell (TEC)-specific deletions of Sav1 (Salvador homolog 1) exhibited aggravated renal TIF, enhanced epithelial-mesenchymal transition-like phenotypic changes, apoptosis, and proliferation after unilateral ureteral obstruction (UUO). Moreover, Sav1 depletion in TECs increased transforming growth factor (TGF)-β and activated β-catenin expression after UUO, which likely accounts for the abovementioned enhanced TEC fibrotic phenotype. In addition, TAZ (transcriptional coactivator with PDZ-binding motif), a major downstream effector of the Hippo pathway, was significantly activated in Sav1-knockout mice in vivo. An in vitro study showed that TAZ directly regulates TGF-β and TGF-β receptor II expression. Collectively, our data indicate that the Hippo-Salvador pathway plays a role in the pathogenesis of TIF and that regulating this pathway may be a therapeutic strategy for reducing TIF. PMID:27550469

  3. The Hippo-Salvador signaling pathway regulates renal tubulointerstitial fibrosis.

    PubMed

    Seo, Eunjeong; Kim, Wan-Young; Hur, Jeongmi; Kim, Hanbyul; Nam, Sun Ah; Choi, Arum; Kim, Yu-Mi; Park, Sang Hee; Chung, Chaeuk; Kim, Jin; Min, Soohong; Myung, Seung-Jae; Lim, Dae-Sik; Kim, Yong Kyun

    2016-01-01

    Renal tubulointerstitial fibrosis (TIF) is the final pathway of various renal injuries that result in chronic kidney disease. The mammalian Hippo-Salvador signaling pathway has been implicated in the regulation of cell proliferation, cell death, tissue regeneration, and tumorigenesis. Here, we report that the Hippo-Salvador pathway plays a role in disease development in patients with TIF and in a mouse model of TIF. Mice with tubular epithelial cell (TEC)-specific deletions of Sav1 (Salvador homolog 1) exhibited aggravated renal TIF, enhanced epithelial-mesenchymal transition-like phenotypic changes, apoptosis, and proliferation after unilateral ureteral obstruction (UUO). Moreover, Sav1 depletion in TECs increased transforming growth factor (TGF)-β and activated β-catenin expression after UUO, which likely accounts for the abovementioned enhanced TEC fibrotic phenotype. In addition, TAZ (transcriptional coactivator with PDZ-binding motif), a major downstream effector of the Hippo pathway, was significantly activated in Sav1-knockout mice in vivo. An in vitro study showed that TAZ directly regulates TGF-β and TGF-β receptor II expression. Collectively, our data indicate that the Hippo-Salvador pathway plays a role in the pathogenesis of TIF and that regulating this pathway may be a therapeutic strategy for reducing TIF. PMID:27550469

  4. Nutrient-sensing pathways and metabolic regulation in stem cells.

    PubMed

    Ochocki, Joshua D; Simon, M Celeste

    2013-10-14

    Stem cells exert precise regulation to maintain a balance of self-renewal and differentiation programs to sustain tissue homeostasis throughout the life of an organism. Recent evidence suggests that this regulation is modulated, in part, via metabolic changes and modifications of nutrient-sensing pathways such as mTOR and AMPK. It is becoming increasingly clear that stem cells inhibit oxidative phosphorylation in favor of aerobic glycolysis for energy production. Recent progress has detailed the molecular mechanisms of this metabolic phenotype and has offered insight into new metabolic pathways that may be involved in stem cell homeostasis. PMID:24127214

  5. The Hippo tumor suppressor pathway regulates intestinal stem cell regeneration.

    PubMed

    Karpowicz, Phillip; Perez, Jessica; Perrimon, Norbert

    2010-12-01

    Identification of the signaling pathways that control the proliferation of stem cells (SCs), and whether they act in a cell or non-cell autonomous manner, is key to our understanding of tissue homeostasis and cancer. In the adult Drosophila midgut, the Jun N-Terminal Kinase (JNK) pathway is activated in damaged enterocyte cells (ECs) following injury. This leads to the production of Upd cytokines from ECs, which in turn activate the Janus kinase (JAK)/Signal transducer and activator of transcription (STAT) pathway in Intestinal SCs (ISCs), stimulating their proliferation. In addition, the Hippo pathway has been recently implicated in the regulation of Upd production from the ECs. Here, we show that the Hippo pathway target, Yorkie (Yki), also plays a crucial and cell-autonomous role in ISCs. Activation of Yki in ISCs is sufficient to increase ISC proliferation, a process involving Yki target genes that promote division, survival and the Upd cytokines. We further show that prior to injury, Yki activity is constitutively repressed by the upstream Hippo pathway members Fat and Dachsous (Ds). These findings demonstrate a cell-autonomous role for the Hippo pathway in SCs, and have implications for understanding the role of this pathway in tumorigenesis and cancer stem cells. PMID:21098564

  6. Feedback Regulation of Kinase Signaling Pathways by AREs and GREs.

    PubMed

    Vlasova-St Louis, Irina; Bohjanen, Paul R

    2016-01-01

    In response to environmental signals, kinases phosphorylate numerous proteins, including RNA-binding proteins such as the AU-rich element (ARE) binding proteins, and the GU-rich element (GRE) binding proteins. Posttranslational modifications of these proteins lead to a significant changes in the abundance of target mRNAs, and affect gene expression during cellular activation, proliferation, and stress responses. In this review, we summarize the effect of phosphorylation on the function of ARE-binding proteins ZFP36 and ELAVL1 and the GRE-binding protein CELF1. The networks of target mRNAs that these proteins bind and regulate include transcripts encoding kinases and kinase signaling pathways (KSP) components. Thus, kinase signaling pathways are involved in feedback regulation, whereby kinases regulate RNA-binding proteins that subsequently regulate mRNA stability of ARE- or GRE-containing transcripts that encode components of KSP. PMID:26821046

  7. Feedback Regulation of Kinase Signaling Pathways by AREs and GREs

    PubMed Central

    Vlasova-St. Louis, Irina; Bohjanen, Paul R.

    2016-01-01

    In response to environmental signals, kinases phosphorylate numerous proteins, including RNA-binding proteins such as the AU-rich element (ARE) binding proteins, and the GU-rich element (GRE) binding proteins. Posttranslational modifications of these proteins lead to a significant changes in the abundance of target mRNAs, and affect gene expression during cellular activation, proliferation, and stress responses. In this review, we summarize the effect of phosphorylation on the function of ARE-binding proteins ZFP36 and ELAVL1 and the GRE-binding protein CELF1. The networks of target mRNAs that these proteins bind and regulate include transcripts encoding kinases and kinase signaling pathways (KSP) components. Thus, kinase signaling pathways are involved in feedback regulation, whereby kinases regulate RNA-binding proteins that subsequently regulate mRNA stability of ARE- or GRE-containing transcripts that encode components of KSP. PMID:26821046

  8. Eosinophil granule cationic proteins regulate the classical pathway of complement.

    PubMed Central

    Weiler, J M; Edens, R E; Bell, C S; Gleich, G J

    1995-01-01

    Major basic protein, the primary constituent of eosinophil granules, regulates the alternative and classical pathways of complement. Major basic protein and other eosinophil granule cationic proteins, which are important in mediating tissue damage in allergic disease, regulate the alternative pathway by interfering with C3b interaction with factor B to assemble an alternative pathway C3 convertase. In the present study, eosinophil peroxidase, eosinophil cationic protein and eosinophil-derived neurotoxin, as well as major basic protein, were examined for capacity to regulate the classical pathway. Eosinophil peroxidase, eosinophil cationic protein and major basic protein inhibited formation of cell-bound classical pathway C3 convertase (EAC1,4b,2a), causing 50% inhibition of complement-mediated lysis at about 0.19, 0.75 and 0.5 micrograms/10(7) cellular intermediates, respectively. Eosinophil-derived neurotoxin had no activity on this pathway of complement. The eosinophil granule proteins were examined for activity on the formation of the membrane attack complex. Major basic protein and eosinophil cationic protein had no activity on terminal lysis. In contrast, eosinophil peroxidase inhibited lysis of EAC1,4b,2a,3b,5b, but had only minimal activity on later events in complement lysis. These polycations were then examined to determine the site(s) at which they regulated the early classical pathway. Eosinophil granule polycationic proteins: (1) reduced the Zmax at all time points but had only minimal effect on the Tmax during the formation of the classical pathway C3 convertase (EAC1,4b,2a); (2) inhibited formation of EAC1,4b,2a proportional to C4 but independent of C2 concentration; (3) inhibited fluid phase formation of C1,4b,2a, as reflected by a decrease in C1-induced consumption of C2 over time; and (4) inhibited C1 activity over time without a direct effect on either C4 or C2. These observations suggest that polycations regulate the early classical pathway by

  9. Regulation of methanol utilisation pathway genes in yeasts

    PubMed Central

    Hartner, Franz S; Glieder, Anton

    2006-01-01

    Methylotrophic yeasts such as Candida boidinii, Hansenula polymorpha, Pichia methanolica and Pichia pastoris are an emerging group of eukaryotic hosts for recombinant protein production with an ever increasing number of applications during the last 30 years. Their applications are linked to the use of strong methanol-inducible promoters derived from genes of the methanol utilisation pathway. These promoters are tightly regulated, highly repressed in presence of non-limiting concentrations of glucose in the medium and strongly induced if methanol is used as carbon source. Several factors involved in this tight control and their regulatory effects have been described so far. This review summarises available data about the regulation of promoters from methanol utilisation pathway genes. Furthermore, the role of cis and trans acting factors (e.g. transcription factors, glucose processing enzymes) in the expression of methanol utilisation pathway genes is reviewed both in the context of the native cell environment as well as in heterologous hosts. PMID:17169150

  10. Mechanism and regulation of the nonsense-mediated decay pathway

    PubMed Central

    Hug, Nele; Longman, Dasa; Cáceres, Javier F.

    2016-01-01

    The Nonsense-mediated mRNA decay (NMD) pathway selectively degrades mRNAs harboring premature termination codons (PTCs) but also regulates the abundance of a large number of cellular RNAs. The central role of NMD in the control of gene expression requires the existence of buffering mechanisms that tightly regulate the magnitude of this pathway. Here, we will focus on the mechanism of NMD with an emphasis on the role of RNA helicases in the transition from NMD complexes that recognize a PTC to those that promote mRNA decay. We will also review recent strategies aimed at uncovering novel trans-acting factors and their functional role in the NMD pathway. Finally, we will describe recent progress in the study of the physiological role of the NMD response. PMID:26773057

  11. Smad8/9 Is Regulated Through the BMP Pathway.

    PubMed

    Katakawa, Yuko; Funaba, Masayuki; Murakami, Masaru

    2016-08-01

    Members of the transforming growth factor-β (TGF-β) family function through Smad-dependent and Smad-independent pathways. The Smad-dependent pathway is stimulated through the phosphorylation of receptor-regulated Smad (R-Smad) and inhibited through the dephosphorylation of R-Smad or the gene induction of inhibitory Smad (I-Smad). Little information is available on the regulation of R-Smad gene expression. BMP4 potentiated the up-regulation of Smad8/9 expression in C2C12, H9c2, 3T3-L1, HepG2, B16, and primary fibroblasts. BMP4-induced Smad8/9 expression was cycloheximide-insensitive and LDN-193189-sensitive, suggesting a direct event mediated through BMP type I receptors. BMP4 transcriptionally stimulated the Smad8/9 gene, and BMP-responsive elements (BREs) spanning nt -121 to nt -44 are involved in the up-regulation of Smad8/9 expression in response to BMP4. Phosphorylated Smad1/5/8/9 specifically bound to the BREs of Smad8/9 gene. The present study reveals that Smad8/9 is a unique R-Smad regulated through the BMP pathway at the mRNA level. J. Cell. Biochem. 117: 1788-1796, 2016. © 2016 Wiley Periodicals, Inc. PMID:26748560

  12. Transcriptional Regulation of Carbohydrate Utilization Pathways in the Bifidobacterium Genus

    PubMed Central

    Khoroshkin, Matvei S.; Leyn, Semen A.; Van Sinderen, Douwe; Rodionov, Dmitry A.

    2016-01-01

    Bifidobacteria, which represent common commensals of mammalian gut, are believed to have positive effects on human health. The influence of certain non-digestible carbohydrates (and their use as so-called prebiotics) on growth and metabolic activity of bifidobacteria is of increasing interest; however, mechanisms of transcriptional control of carbohydrate metabolism are poorly understood in these species. We used a comparative genomics approach to reconstruct carbohydrate utilization pathways and transcriptional regulons in 10 Bifidobacterium genomes. Analysis of regulatory gene regions revealed candidate DNA motifs and reconstructed regulons for 268 transcription factors from the LacI, ROK, DeoR, AraC, GntR, and TetR families that form 64 orthologous groups of regulators. Most of the reconstructed regulons are local and control specific catabolic pathways for host- and diet-derived glycans and monosaccharides. Mosaic distributions of many of these local regulators across Bifidobacterium species correlate with distribution of corresponding catabolic pathways. In contrast, the maltose, galactose, sucrose, and fructose regulons, as well as a novel global LacI-family regulator that is predicted to control the central carbohydrate metabolism and arabinose catabolism genes, are universally present in all 10 studied bifidobacteria. A novel group of TetR-family regulators presumably controls the glucoside and galactoside utilization pathways. Paralogs of the ribose repressor RbsR control the pyrimidine nucleoside utilization genes. Multiple paralogs of the maltose regulator MalR co-regulate large sets of genes involved in maltodextrin utilization. The inferred metabolic regulons provide new insights on diverse carbohydrate utilization networks in bifidobacteria that can be employed in metabolic modeling, phenotype prediction and the rational development of novel prebiotics. PMID:26903998

  13. Signal Transduction Pathways that Regulate CAB Gene Expression

    SciTech Connect

    Chory, Joanne

    2006-01-16

    The process of chloroplast differentiation, involves the coordinate regulation of many nuclear and chloroplast genes. The cues for the initiation of this developmental program are both extrinsic (e.g., light) and intrinsic (cell-type and plastid signals). During this project period, we utilized a molecular genetic approach to select for Arabidopsis mutants that did not respond properly to environmental light conditions, as well as mutants that were unable to perceive plastid damage. These latter mutants, called gun mutants, define two retrograde signaling pathways that regulate nuclear gene expression in response to chloroplasts. A major finding was to identify a signal from chloroplasts that regulates nuclear gene transcription. This signal is the build-up of Mg-Protoporphyrin IX, a key intermediate of the chlorophyll biosynthetic pathway. The signaling pathways downstream of this signal are currently being studied. Completion of this project has provided an increased understanding of the input signals and retrograde signaling pathways that control nuclear gene expression in response to the functional state of chloroplasts. These studies should ultimately influence our abilities to manipulate plant growth and development, and will aid in the understanding of the developmental control of photosynthesis.

  14. Signal Transduction Pathways that Regulate CAB Gene Expression

    SciTech Connect

    Chory, Joanne

    2004-12-31

    The process of chloroplast differentiation, involves the coordinate regulation of many nuclear and chloroplast genes. The cues for the initiation of this developmental program are both extrinsic (e.g., light) and intrinsic (cell-type and plastid signals). During this project period, we utilized a molecular genetic approach to select for Arabidopsis mutants that did not respond properly to environmental light conditions, as well as mutants that were unable to perceive plastid damage. These latter mutants, called gun mutants, define two retrograde signaling pathways that regulate nuclear gene expression in response to chloroplasts. A major finding was to identify a signal from chloroplasts that regulates nuclear gene transcription. This signal is the build-up of Mg-Protoporphyrin IX, a key intermediate of the chlorophyll biosynthetic pathway. The signaling pathways downstream of this signal are currently being studied. Completion of this project has provided an increased understanding of the input signals and retrograde signaling pathways that control nuclear gene expression in response to the functional state of chloroplasts. These studies should ultimately influence our abilities to manipulate plant growth and development, and will aid in the understanding of the developmental control of photosynthesis.

  15. YAP regulates neuronal differentiation through Sonic hedgehog signaling pathway

    SciTech Connect

    Lin, Yi-Ting; Ding, Jing-Ya; Li, Ming-Yang; Yeh, Tien-Shun; Wang, Tsu-Wei; Yu, Jenn-Yah

    2012-09-10

    Tight regulation of cell numbers by controlling cell proliferation and apoptosis is important during development. Recently, the Hippo pathway has been shown to regulate tissue growth and organ size in Drosophila. In mammalian cells, it also affects cell proliferation and differentiation in various tissues, including the nervous system. Interplay of several signaling cascades, such as Notch, Wnt, and Sonic Hedgehog (Shh) pathways, control cell proliferation during neuronal differentiation. However, it remains unclear whether the Hippo pathway coordinates with other signaling cascades in regulating neuronal differentiation. Here, we used P19 cells, a mouse embryonic carcinoma cell line, as a model to study roles of YAP, a core component of the Hippo pathway, in neuronal differentiation. P19 cells can be induced to differentiate into neurons by expressing a neural bHLH transcription factor gene Ascl1. Our results showed that YAP promoted cell proliferation and inhibited neuronal differentiation. Expression of Yap activated Shh but not Wnt or Notch signaling activity during neuronal differentiation. Furthermore, expression of Yap increased the expression of Patched homolog 1 (Ptch1), a downstream target of the Shh signaling. Knockdown of Gli2, a transcription factor of the Shh pathway, promoted neuronal differentiation even when Yap was over-expressed. We further demonstrated that over-expression of Yap inhibited neuronal differentiation in primary mouse cortical progenitors and Gli2 knockdown rescued the differentiation defect in Yap over-expressing cells. In conclusion, our study reveals that Shh signaling acts downstream of YAP in regulating neuronal differentiation. -- Highlights: Black-Right-Pointing-Pointer YAP promotes cell proliferation and inhibits neuronal differentiation in P19 cells. Black-Right-Pointing-Pointer YAP promotes Sonic hedgehog signaling activity during neuronal differentiation. Black-Right-Pointing-Pointer Knockdown of Gli2 rescues the Yap

  16. SOCS Regulation of the JAK/STAT Signalling Pathway

    PubMed Central

    Croker, Ben A.; Kiu, Hiu; Nicholson, Sandra E.

    2008-01-01

    The Suppressor Of Cytokine Signalling (SOCS) proteins were, as their name suggests, first described as inhibitors of cytokine signalling. While their actions clearly now extend to other intracellular pathways, they remain key negative regulators of cytokine and growth factor signalling. In this review we focus on the mechanics of SOCS action and the complexities of the mouse models that have underpinned our current understanding of SOCS biology. PMID:18708154

  17. A divergent canonical WNT-signaling pathway regulates microtubule dynamics

    PubMed Central

    Ciani, Lorenza; Krylova, Olga; Smalley, Matthew J.; Dale, Trevor C.; Salinas, Patricia C.

    2004-01-01

    Dishevelled (DVL) is associated with axonal microtubules and regulates microtubule stability through the inhibition of the serine/threonine kinase, glycogen synthase kinase 3β (GSK-3β). In the canonical WNT pathway, the negative regulator Axin forms a complex with β-catenin and GSK-3β, resulting in β-catenin degradation. Inhibition of GSK-3β by DVL increases β-catenin stability and TCF transcriptional activation. Here, we show that Axin associates with microtubules and unexpectedly stabilizes microtubules through DVL. In turn, DVL stabilizes microtubules by inhibiting GSK-3β through a transcription- and β-catenin–independent pathway. More importantly, axonal microtubules are stabilized after DVL localizes to axons. Increased microtubule stability is correlated with a decrease in GSK-3β–mediated phosphorylation of MAP-1B. We propose a model in which Axin, through DVL, stabilizes microtubules by inhibiting a pool of GSK-3β, resulting in local changes in the phosphorylation of cellular targets. Our data indicate a bifurcation in the so-called canonical WNT-signaling pathway to regulate microtubule stability. PMID:14734535

  18. p53 regulates the mevalonate pathway in human glioblastoma multiforme

    PubMed Central

    Laezza, C; D'Alessandro, A; Di Croce, L; Picardi, P; Ciaglia, E; Pisanti, S; Malfitano, A M; Comegna, M; Faraonio, R; Gazzerro, P; Bifulco, M

    2015-01-01

    The mevalonate (MVA) pathway is an important metabolic pathway implicated in multiple aspects of tumorigenesis. In this study, we provided evidence that p53 induces the expression of a group of enzymes of the MVA pathway including 3′-hydroxy-3′-methylglutaryl-coenzyme A reductase, MVA kinase, farnesyl diphosphate synthase and farnesyl diphosphate farnesyl transferase 1, in the human glioblastoma multiforme cell line, U343 cells, and in normal human astrocytes, NHAs. Genetic and pharmacologic perturbation of p53 directly influences the expression of these genes. Furthermore, p53 is recruited to the gene promoters in designated p53-responsive elements, thereby increasing their transcription. Such effect was abolished by site-directed mutagenesis in the p53-responsive element of promoter of the genes. These findings highlight another aspect of p53 functions unrelated to tumor suppression and suggest p53 as a novel regulator of the MVA pathway providing insight into the role of this pathway in cancer progression. PMID:26469958

  19. Epigenetic regulator Lid maintains germline stem cells through regulating JAK-STAT signaling pathway activity

    PubMed Central

    Tarayrah, Lama; Li, Yuping; Gan, Qiang; Chen, Xin

    2015-01-01

    ABSTRACT Signaling pathways and epigenetic mechanisms have both been shown to play essential roles in regulating stem cell activity. While the role of either mechanism in this regulation is well established in multiple stem cell lineages, how the two mechanisms interact to regulate stem cell activity is not as well understood. Here we report that in the Drosophila testis, an H3K4me3-specific histone demethylase encoded by little imaginal discs (lid) maintains germline stem cell (GSC) mitotic index and prevents GSC premature differentiation. Lid is required in germ cells for proper expression of the Stat92E transcription factor, the downstream effector of the Janus kinase signal transducer and activator of transcription (JAK-STAT) signaling pathway. Our findings support a germ cell autonomous role for the JAK-STAT pathway in maintaining GSCs and place Lid as an upstream regulator of this pathway. Our study provides new insights into the biological functions of a histone demethylase in vivo and sheds light on the interaction between epigenetic mechanisms and signaling pathways in regulating stem cell activities. PMID:26490676

  20. microRNA Processing Pathway Regulates Olfactory Neuron Morphogenesis

    PubMed Central

    Berdnik, Daniela; Fan, Audrey P.; Potter, Christopher J.; Luo, Liqun

    2008-01-01

    Summary The micro(mi)RNA processing pathway produces miRNAs as posttranscriptional regulators of gene expression. The nuclear RNase III Drosha catalyzes the first processing step together with the dsRNA binding protein DGCR8/Pasha generating pre-miRNAs [1, 2]. The next cleavage employs the cytoplasmic RNase III Dicer producing miRNA duplexes [3, 4]. Finally, Argonautes are recruited with miRNAs into an RNA-induced silencing complex for mRNA recognition (Figure 1A). Here, we identify two members of the miRNA pathway, Pasha and Dicer-1, in a forward genetic screen for mutations that disrupt wiring specificity of Drosophila olfactory projection neurons (PNs). The olfactory system is built as discrete map of highly stereotyped neuronal connections [5, 6]. Each PN targets dendrites to a specific glomerulus in the antennal lobe and projects axons stereotypically into higher brain centers [7–9]. In selected PN classes, pasha and Dicer-1 mutants cause specific PN dendrite mistargeting in the antennal lobe and altered axonal terminations in higher brain centers. Furthermore, Pasha and Dicer-1 act cell-autonomously in postmitotic neurons to regulate dendrite and axon targeting during development. However, Argonaute-1 and Argonaute-2 are dispensable for PN morphogenesis. Our findings suggest a role for the miRNA processing pathway in establishing wiring specificity in the nervous system. PMID:19013069

  1. MicroRNA processing pathway regulates olfactory neuron morphogenesis.

    PubMed

    Berdnik, Daniela; Fan, Audrey P; Potter, Christopher J; Luo, Liqun

    2008-11-25

    The microRNA (miRNA) processing pathway produces miRNAs as posttranscriptional regulators of gene expression. The nuclear RNase III Drosha catalyzes the first processing step together with the dsRNA binding protein DGCR8/Pasha generating pre-miRNAs [1, 2]. The next cleavage employs the cytoplasmic RNase III Dicer producing miRNA duplexes [3, 4]. Finally, Argonautes are recruited with miRNAs into an RNA-induced silencing complex for mRNA recognition (Figure 1A). Here, we identify two members of the miRNA pathway, Pasha and Dicer-1, in a forward genetic screen for mutations that disrupt wiring specificity of Drosophila olfactory projection neurons (PNs). The olfactory system is built as discrete map of highly stereotyped neuronal connections [5, 6]. Each PN targets dendrites to a specific glomerulus in the antennal lobe and projects axons stereotypically into higher brain centers [7-9]. In selected PN classes, pasha and Dicer-1 mutants cause specific PN dendrite mistargeting in the antennal lobe and altered axonal terminations in higher brain centers. Furthermore, Pasha and Dicer-1 act cell autonomously in postmitotic neurons to regulate dendrite and axon targeting during development. However, Argonaute-1 and Argonaute-2 are dispensable for PN morphogenesis. Our findings suggest a role for the miRNA processing pathway in establishing wiring specificity in the nervous system. PMID:19013069

  2. Autopalmitoylation of TEAD Proteins Regulates Transcriptional Output of Hippo Pathway

    PubMed Central

    Chan, PuiYee; Han, Xiao; Zheng, Baohui; DeRan, Michael; Yu, Jianzhong; Jarugumilli, Gopala K.; Deng, Hua; Pan, Duojia; Luo, Xuelian; Wu, Xu

    2016-01-01

    TEA domain (TEAD) transcription factors bind to the co-activator YAP/TAZ, and regulate the transcriptional output of Hippo pathway, playing critical roles in organ size control and tumorigenesis. Protein S-palmitoylation attaches fatty acid (palmitate) to cysteine residues, and regulates protein trafficking, membrane localization and signaling activities. Using activity-based chemical probes, we discovered that human TEADs possess intrinsic palmitoylating enzyme-like activities, and undergo autopalmitoylation at evolutionarily conserved cysteine residues under physiological conditions. We determined the crystal structures of lipid-bound TEADs, and found that the lipid chain of palmitate inserts into a conserved deep hydrophobic pocket. Strikingly, palmitoylation is required for TEAD’s binding to YAP/TAZ, but dispensable for the binding to Vgll4 tumor suppressor. In addition, palmitoylation does not alter TEAD’s localization. Moreover, TEAD palmitoylation-deficient mutants impaired TAZ-mediated muscle differentiation in vitro, and Yorkie-mediated tissue overgrowth in Drosophila in vivo. Our study directly linked autopalmitoylation to the transcriptional regulation of Hippo pathway. PMID:26900866

  3. Calcineurin Signaling Regulates Neural Induction Through Antagonizing the BMP Pathway

    PubMed Central

    Cho, Ahryon; Deng, Suhua; Chen, Lei; Miller, Erik; Wernig, Marius; Graef, Isabella A

    2014-01-01

    Summary Development of the nervous system begins with neural induction, which is controlled by complex signaling networks functioning in concert with one another. Fine-tuning of the bone morphogenetic protein (BMP) pathway is essential for neural induction in the developing embryo. However, the molecular mechanisms by which cells integrate the signaling pathways that contribute to neural induction have remained unclear. We find that neural induction is dependent on the Ca2+-activated phosphatase calcineurin (CaN). FGF-regulated Ca2+ entry activates CaN, which directly and specifically dephosphorylates BMP-regulated Smad1/5 proteins. Genetic and biochemical analyses revealed that CaN adjusts the strength and transcriptional output of BMP signaling and that a reduction of CaN activity leads to an increase of Smad1/5-regulated transcription. As a result, FGF-activated CaN signaling opposes BMP signaling during gastrulation, thereby promoting neural induction and the development of anterior structures. PMID:24698271

  4. SEPT4 is regulated by the Notch signaling pathway.

    PubMed

    Liu, Wenbin

    2012-04-01

    Notch receptor-mediated signaling is an evolutionarily conserved pathway that regulates diverse developmental processes and its dysregulation has been implicated in a variety of developmental disorders and cancers. Notch functions in these processes by activating expression of its target genes. Septin 4 (SEPT4) is a polymerizing GTP-binding protein that serves as scaffold for diverse molecules and is involved in cell proliferation and apoptosis. After activation of the Notch signal, the expression of SEPT4 is up-regulated and cell proliferation is inhibited. When the Notch signal is inhibited by the CSL (CBF1/Su(H)/Lag-1)-binding-domain-negative Mastermind-like protein 1, the expression of SEPT4 is down-regulated, proliferation and colony formation of cells are promoted, but cell adhesion ability is decreased. Nevertheless, the SEPT4 expression is not affected after knock-down of CSL. Meanwhile, if SEPT4 activity is inhibited through RNA interference, the protein level and activity of NOTCH1 remains unchanged, but cell proliferation is dysregulated. This indicates that SEPT4 is a Notch target gene. This relationship between Notch signaling pathway and SEPT4 offers a potential basis for further study of developmental control and carcinogenesis. PMID:21938432

  5. Regulation of ribosomal DNA amplification by the TOR pathway

    PubMed Central

    Jack, Carmen V.; Cruz, Cristina; Hull, Ryan M.; Keller, Markus A.; Ralser, Markus; Houseley, Jonathan

    2015-01-01

    Repeated regions are widespread in eukaryotic genomes, and key functional elements such as the ribosomal DNA tend to be formed of high copy repeated sequences organized in tandem arrays. In general, high copy repeats are remarkably stable, but a number of organisms display rapid ribosomal DNA amplification at specific times or under specific conditions. Here we demonstrate that target of rapamycin (TOR) signaling stimulates ribosomal DNA amplification in budding yeast, linking external nutrient availability to ribosomal DNA copy number. We show that ribosomal DNA amplification is regulated by three histone deacetylases: Sir2, Hst3, and Hst4. These enzymes control homologous recombination-dependent and nonhomologous recombination-dependent amplification pathways that act in concert to mediate rapid, directional ribosomal DNA copy number change. Amplification is completely repressed by rapamycin, an inhibitor of the nutrient-responsive TOR pathway; this effect is separable from growth rate and is mediated directly through Sir2, Hst3, and Hst4. Caloric restriction is known to up-regulate expression of nicotinamidase Pnc1, an enzyme that enhances Sir2, Hst3, and Hst4 activity. In contrast, normal glucose concentrations stretch the ribosome synthesis capacity of cells with low ribosomal DNA copy number, and we find that these cells show a previously unrecognized transcriptional response to caloric excess by reducing PNC1 expression. PNC1 down-regulation forms a key element in the control of ribosomal DNA amplification as overexpression of PNC1 substantially reduces ribosomal DNA amplification rate. Our results reveal how a signaling pathway can orchestrate specific genome changes and demonstrate that the copy number of repetitive DNA can be altered to suit environmental conditions. PMID:26195783

  6. Autophagy as a Regulated Pathway of Cellular Degradation

    PubMed Central

    Klionsky, Daniel J.; Emr, Scott D.

    2009-01-01

    Macroautophagy is a dynamic process involving the rearrangement of subcellular membranes to sequester cytoplasm and organelles for delivery to the lysosome or vacuole where the sequestered cargo is degraded and recycled. This process takes place in all eukaryotic cells. It is highly regulated through the action of various kinases, phosphatases, and guanosine triphosphatases (GTPases). The core protein machinery that is necessary to drive formation and consumption of intermediates in the macroautophagy pathway includes a ubiquitin-like protein conjugation system and a protein complex that directs membrane docking and fusion at the lysosome or vacuole. Macroautophagy plays an important role in developmental processes, human disease, and cellular response to nutrient deprivation. PMID:11099404

  7. Bioinformatic dissecting of TP53 regulation pathway underlying butyrate-induced histone modification in epigenetic regulation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Butyrate affects cell proliferation, differentiation and motility. Butyrate inhibits histone deacetylase (HDAC) activities and induces cell cycle arrest and apoptosis. TP53 is one of the most active upstream regulators discovered by IPA in our RNA sequencing data set. The TP53 signaling pathway pl...

  8. Synaptic activity regulates AMPA receptor trafficking through different recycling pathways.

    PubMed

    Zheng, Ning; Jeyifous, Okunola; Munro, Charlotte; Montgomery, Johanna M; Green, William N

    2015-01-01

    Changes in glutamatergic synaptic strength in brain are dependent on AMPA-type glutamate receptor (AMPAR) recycling, which is assumed to occur through a single local pathway. In this study, we present evidence that AMPAR recycling occurs through different pathways regulated by synaptic activity. Without synaptic stimulation, most AMPARs recycled in dynamin-independent endosomes containing the GTPase, Arf6. Few AMPARs recycled in dynamin-dependent endosomes labeled by transferrin receptors (TfRs). AMPAR recycling was blocked by alterations in the GTPase, TC10, which co-localized with Arf6 endosomes. TC10 mutants that reduced AMPAR recycling had no effect on increased AMPAR levels with long-term potentiation (LTP) and little effect on decreased AMPAR levels with long-term depression. However, internalized AMPAR levels in TfR-containing recycling endosomes increased after LTP, indicating increased AMPAR recycling through the dynamin-dependent pathway with synaptic plasticity. LTP-induced AMPAR endocytosis is inconsistent with local recycling as a source of increased surface receptors, suggesting AMPARs are trafficked from other sites. PMID:25970033

  9. [Sonic Hedgehog signaling pathway and regulation of inner ear development].

    PubMed

    Chen, Zhi-Qiang; Han, Xin-Huan; Cao, Xin

    2013-09-01

    During inner ear development, Sonic Hedgehog (Shh) signaling pathway is involved in the ventral otic identity, cell fate determination of statoacoustic ganglion neurons and hair cell development. Shh protein, secreted from floor plate, antagonizes Wnt protein from roof plate, which refines and maintains dorsoventral axial patterning in the ear. Shh, served as a mitogen during neurogenesis, directly promotes the development of spiral ganglion neuron. After Shh signaling pathway is activated, Ngn1 is freed from Tbx1 repression. As a result, Shh indirectly upregulates the expression of Ngn1, thus regulating neurogenic patterning of inner ear. In addition, Shh regulates the differentiation of hair cells by influencing cell cycle of the progenitor cells located in the cochlea. The basal-to-apical wave of Shh decline ensures the normal devel- opment pattern of hair cells. It is confirmed by a quantity of researches conducted in both animals and patients with hereditary hearing impairment that abnormal Shh signaling results in aberrant transcription of target genes, disturbance of the proper development of inner ear, and human hearing impairment. In humans, diseases accompanied by hearing disorders caused by abnormal Shh signaling include Greig cephalopolysyndactyly syndrome (GCPS), Pallister-Hall syndrome (PHS), Waardenburg syndrome (WS) and medulloblastoma, etc. This review would provide a theoretical basis for further study of molecular mechanisms and clinical use of inner ear development. PMID:24400478

  10. Integration of Shh and Wnt Signaling Pathways Regulating Hematopoiesis.

    PubMed

    Zhou, Zhigang; Wan, Liping; Wang, Chun; Zhou, Kun

    2015-12-01

    To investigate the spatial and temporal programmed expression of Shh and Wnt members during key stages of definitive hematopoiesis and the possible mechanism of Shh and Wnt signaling pathways regulating the proliferation of hematopoietic progenitor cells (HPCs). Spatial and temporal programmed gene expression of Shh and Wnt signaling during hematopoiesis corresponded with c-kit(+)lin(-) HPCs proliferation. C-kit(+)Lin(-) populations derived from aorta-gonad-mesonephros (AGM) of Balb/c mice at E10.5 with increased expression of Shh and Wnt3a demonstrated a greater potential for proliferation. Additionally, supplementation with soluble Shh N-terminal peptide promoted the proliferation of c-kit(+)Lin(-) populations by activating the Wnt signaling pathway, an effect which was inhibited by blocking Shh signaling. A specific inhibitor of wnt signaling was capable of inhibiting Shh-induced proliferation in a similar manner to shh inhibitor. Our results provide valuable information on Shh and Wnt signaling involved in hematopoiesis and highlight the importance of interaction of Shh and Wnt signaling in regulating HPCs proliferation. PMID:26378473

  11. Identification of a neurovascular signaling pathway regulating seizures in mice

    PubMed Central

    Fredriksson, Linda; Stevenson, Tamara K; Su, Enming J; Ragsdale, Margaret; Moore, Shannon; Craciun, Stefan; Schielke, Gerald P; Murphy, Geoffrey G; Lawrence, Daniel A

    2015-01-01

    Objective A growing body of evidence suggests that increased blood–brain barrier (BBB) permeability can contribute to the development of seizures. The protease tissue plasminogen activator (tPA) has been shown to promote BBB permeability and susceptibility to seizures. In this study, we examined the pathway regulated by tPA in seizures. Methods An experimental model of kainate-induced seizures was used in genetically modified mice, including mice deficient in tPA (tPA−/−), its inhibitor neuroserpin (Nsp−/−), or both (Nsp:tPA−/−), and in mice conditionally deficient in the platelet-derived growth factor receptor alpha (PDGFRα). Results Compared to wild-type (WT) mice, Nsp−/− mice have significantly reduced latency to seizure onset and generalization; whereas tPA−/− mice have the opposite phenotype, as do Nsp:tPA−/− mice. Furthermore, interventions that maintain BBB integrity delay seizure propagation, whereas osmotic disruption of the BBB in seizure-resistant tPA−/− mice dramatically reduces the time to seizure onset and accelerates seizure progression. The phenotypic differences in seizure progression between WT, tPA−/−, and Nsp−/− mice are also observed in electroencephalogram recordings in vivo, but absent in ex vivo electrophysiological recordings where regulation of the BBB is no longer necessary to maintain the extracellular environment. Finally, we demonstrate that these effects on seizure progression are mediated through signaling by PDGFRα on perivascular astrocytes. Interpretation Together, these data identify a specific molecular pathway involving tPA-mediated PDGFRα signaling in perivascular astrocytes that regulates seizure progression through control of the BBB. Inhibition of PDGFRα signaling and maintenance of BBB integrity might therefore offer a novel clinical approach for managing seizures. PMID:26273685

  12. The Spectrin cytoskeleton regulates the Hippo signalling pathway

    PubMed Central

    Fletcher, Georgina C; Elbediwy, Ahmed; Khanal, Ichha; Ribeiro, Paulo S; Tapon, Nic; Thompson, Barry J

    2015-01-01

    The Spectrin cytoskeleton is known to be polarised in epithelial cells, yet its role remains poorly understood. Here, we show that the Spectrin cytoskeleton controls Hippo signalling. In the developing Drosophila wing and eye, loss of apical Spectrins (alpha/beta-heavy dimers) produces tissue overgrowth and mis-regulation of Hippo target genes, similar to loss of Crumbs (Crb) or the FERM-domain protein Expanded (Ex). Apical beta-heavy Spectrin binds to Ex and co-localises with it at the apical membrane to antagonise Yki activity. Interestingly, in both the ovarian follicular epithelium and intestinal epithelium of Drosophila, apical Spectrins and Crb are dispensable for repression of Yki, while basolateral Spectrins (alpha/beta dimers) are essential. Finally, the Spectrin cytoskeleton is required to regulate the localisation of the Hippo pathway effector YAP in response to cell density human epithelial cells. Our findings identify both apical and basolateral Spectrins as regulators of Hippo signalling and suggest Spectrins as potential mechanosensors. PMID:25712476

  13. Regulation of iron homeostasis by the p53-ISCU pathway

    PubMed Central

    Funauchi, Yuki; Tanikawa, Chizu; Yi Lo, Paulisally Hau; Mori, Jinichi; Daigo, Yataro; Takano, Atsushi; Miyagi, Yohei; Okawa, Atsushi; Nakamura, Yusuke; Matsuda, Koichi

    2015-01-01

    Accumulation of iron in tissues increases the risk of cancer, but iron regulatory mechanisms in cancer tissues are largely unknown. Here, we report that p53 regulates iron metabolism through the transcriptional regulation of ISCU (iron-sulfur cluster assembly enzyme), which encodes a scaffold protein that plays a critical role in Fe-S cluster biogenesis. p53 activation induced ISCU expression through binding to an intronic p53-binding site. Knockdown of ISCU enhanced the binding of iron regulatory protein 1 (IRP1), a cytosolic Fe-S protein, to an iron-responsive element in the 5′ UTR of ferritin heavy polypeptide 1 (FTH1) mRNA and subsequently reduced the translation of FTH1, a major iron storage protein. In addition, in response to DNA damage, p53 induced FTH1 and suppressed transferrin receptor, which regulates iron entry into cells. HCT116 p53+/+ cells were resistant to iron accumulation, but HCT116 p53−/− cells accumulated intracellular iron after DNA damage. Moreover, excess dietary iron caused significant elevation of serum iron levels in p53−/− mice. ISCU expression was decreased in the majority of human liver cancer tissues, and its reduced expression was significantly associated with p53 mutation. Our finding revealed a novel role of the p53-ISCU pathway in the maintenance of iron homeostasis in hepatocellular carcinogenesis. PMID:26560363

  14. SIRT1 regulates MAPK pathways in vitiligo skin: insight into the molecular pathways of cell survival

    PubMed Central

    Becatti, Matteo; Fiorillo, Claudia; Barygina, Victoria; Cecchi, Cristina; Lotti, Torello; Prignano, Francesca; Silvestro, Agrippino; Nassi, Paolo; Taddei, Niccolò

    2014-01-01

    Vitiligo is an acquired and progressive hypomelanotic disease that manifests as circumscribed depigmented patches on the skin. The aetiology of vitiligo remains unclear, but recent experimental data underline the interactions between melanocytes and other typical skin cells, particularly keratinocytes. Our previous results indicate that keratinocytes from perilesional skin show the features of damaged cells. Sirtuins (silent mating type information regulation 2 homolog) 1, well-known modulators of lifespan in many species, have a role in gene repression, metabolic control, apoptosis and cell survival, DNA repair, development, inflammation, neuroprotection and healthy ageing. In the literature there is no evidence for SIRT1 signalling in vitiligo and its possible involvement in disease progression. Here, biopsies were taken from the perilesional skin of 16 patients suffering from non-segmental vitiligo and SIRT1 signalling was investigated in these cells. For the first time, a new SIRT1/Akt, also known as Protein Kinase B (PKB)/mitogen-activated protein kinase (MAPK) signalling has been revealed in vitiligo. SIRT1 regulates MAPK pathway via Akt-apoptosis signal-regulating kinase-1 and down-regulates pro-apoptotic molecules, leading to decreased oxidative stress and apoptotic cell death in perilesional vitiligo keratinocytes. We therefore propose SIRT1 activation as a novel way of protecting perilesional vitiligo keratinocytes from damage. PMID:24410795

  15. Compartmentalization and Regulation of Sulfate Assimilation Pathways in Plants.

    PubMed

    Bohrer, A-S; Takahashi, H

    2016-01-01

    Plants utilize sulfate to synthesize primary and secondary sulfur-containing metabolites required for growth and survival in the environment. Sulfate is taken up into roots from the soil and distributed to various organs through the functions of membrane-bound sulfate transporters, while it is utilized as the primary substrate for synthesizing sulfur-containing metabolites in the sulfate assimilation pathways. Transporters and enzymes for the assimilative conversion of sulfate are regulated in highly organized manners depending on changes in sulfate supply from the environment and demand for biosynthesis of reduced sulfur compounds in the plant systems. Over the past few decades, the effect of sulfur nutrition on gene expression of sulfate transporters and assimilatory enzymes has been extensively studied with the aim of understanding the full landscape of regulatory networks. PMID:27572125

  16. Pathways of allosteric regulation in Hsp70 chaperones.

    PubMed

    Kityk, Roman; Vogel, Markus; Schlecht, Rainer; Bukau, Bernd; Mayer, Matthias P

    2015-01-01

    Central to the protein folding activity of Hsp70 chaperones is their ability to interact with protein substrates in an ATP-controlled manner, which relies on allosteric regulation between their nucleotide-binding (NBD) and substrate-binding domains (SBD). Here we dissect this mechanism by analysing mutant variants of the Escherichia coli Hsp70 DnaK blocked at distinct steps of allosteric communication. We show that the SBD inhibits ATPase activity by interacting with the NBD through a highly conserved hydrogen bond network, and define the signal transduction pathway that allows bound substrates to trigger ATP hydrolysis. We identify variants deficient in only one direction of allosteric control and demonstrate that ATP-induced substrate release is more important for chaperone activity than substrate-stimulated ATP hydrolysis. These findings provide evidence of an unexpected dichotomic allostery mechanism in Hsp70 chaperones and provide the basis for a comprehensive mechanical model of allostery in Hsp70s. PMID:26383706

  17. Proteolytic regulation of stress response pathways in Escherichia coli.

    PubMed

    Micevski, Dimce; Dougan, David A

    2013-01-01

    Maintaining correct cellular function is a fundamental biological process for all forms of life. A critical aspect of this process is the maintenance of protein homeostasis (proteostasis) in the cell, which is largely performed by a group of proteins, referred to as the protein quality control (PQC) network. This network of proteins, comprised of chaperones and proteases, is critical for maintaining proteostasis not only during favourable growth conditions, but also in response to stress. Indeed proteases play a crucial role in the clearance of unwanted proteins that accumulate during stress, but more importantly, in the activation of various different stress response pathways. In bacteria, the cells response to stress is usually orchestrated by a specific transcription factor (sigma factor). In Escherichia coli there are seven different sigma factors, each of which responds to a particular stress, resulting in the rapid expression of a specific set of genes. The cellular concentration of each transcription factor is tightly controlled, at the level of transcription, translation and protein stability. Here we will focus on the proteolytic regulation of two sigma factors (σ(32) and σ(S)), which control the heat and general stress response pathways, respectively. This review will also briefly discuss the role proteolytic systems play in the clearance of unwanted proteins that accumulate during stress. PMID:23479439

  18. TOR and RAS pathways regulate desiccation tolerance in Saccharomyces cerevisiae

    PubMed Central

    Welch, Aaron Z.; Gibney, Patrick A.; Botstein, David; Koshland, Douglas E.

    2013-01-01

    Tolerance to desiccation in cultures of Saccharomyces cerevisiae is inducible; only one in a million cells from an exponential culture survive desiccation compared with one in five cells in stationary phase. Here we exploit the desiccation sensitivity of exponentially dividing cells to understand the stresses imposed by desiccation and their stress response pathways. We found that induction of desiccation tolerance is cell autonomous and that there is an inverse correlation between desiccation tolerance and growth rate in glucose-, ammonia-, or phosphate-limited continuous cultures. A transient heat shock induces a 5000–fold increase in desiccation tolerance, whereas hyper-ionic, -reductive, -oxidative, or -osmotic stress induced much less. Furthermore, we provide evidence that the Sch9p-regulated branch of the TOR and Ras-cAMP pathway inhibits desiccation tolerance by inhibiting the stress response transcription factors Gis1p, Msn2p, and Msn4p and by activating Sfp1p, a ribosome biogenesis transcription factor. Among 41 mutants defective in ribosome biogenesis, a subset defective in 60S showed a dramatic increase in desiccation tolerance independent of growth rate. We suggest that reduction of a specific intermediate in 60S biogenesis, resulting from conditions such as heat shock and nutrient deprivation, increases desiccation tolerance. PMID:23171550

  19. Adverse outcome pathways: From research to regulation scientific workshop report.

    PubMed

    Kleinstreuer, Nicole C; Sullivan, Kristie; Allen, David; Edwards, Stephen; Mendrick, Donna L; Embry, Michelle; Matheson, Joanna; Rowlands, J Craig; Munn, Sharon; Maull, Elizabeth; Casey, Warren

    2016-04-01

    An adverse outcome pathway (AOP) helps to organize existing knowledge on chemical mode of action, starting with a molecular initiating event such as receptor binding, continuing through key events, and ending with an adverse outcome such as reproductive impairment. AOPs can help identify knowledge gaps where more research is needed to understand the underlying mechanisms, aid in chemical hazard characterization, and guide the development of new testing approaches that use fewer or no animals. A September 2014 workshop in Bethesda, Maryland considered how the AOP concept could improve regulatory assessments of chemical toxicity. Scientists from 21 countries, representing industry, academia, regulatory agencies, and special interest groups, attended the workshop, titled Adverse Outcome Pathways: From Research to Regulation. Workshop plenary presentations were followed by breakout sessions that considered regulatory acceptance of AOPs and AOP-based tools, criteria for building confidence in an AOP for regulatory use, and requirements to build quantitative AOPs and AOP networks. Discussions during the closing session emphasized a need to increase transparent and inclusive collaboration, especially with disciplines outside of toxicology. Additionally, to increase impact, working groups should be established to systematically prioritize and develop AOPs. Multiple collaborative projects and follow-up activities resulted from the workshop. PMID:26774756

  20. Cross-regulation of signaling pathways: An example of nuclear hormone receptors and the canonical Wnt pathway

    SciTech Connect

    Beildeck, Marcy E.; Gelmann, Edward P.; Byers, Stephen W.

    2010-07-01

    Predicting the potential physiological outcome(s) of any given molecular pathway is complex because of cross-talk with other pathways. This is particularly evident in the case of the nuclear hormone receptor and canonical Wnt pathways, which regulate cell growth and proliferation, differentiation, apoptosis, and metastatic potential in numerous tissues. These pathways are known to intersect at many levels: in the intracellular space, at the membrane, in the cytoplasm, and within the nucleus. The outcomes of these interactions are important in the control of stem cell differentiation and maintenance, feedback loops, and regulating oncogenic potential. The aim of this review is to demonstrate the importance of considering pathway cross-talk when predicting functional outcomes of signaling, using nuclear hormone receptor/canonical Wnt pathway cross-talk as an example.

  1. Multiple pathways regulating the calorie restriction response in yeast.

    PubMed

    Rahat, Ofer; Maoz, Noam; Cohen, Haim Y

    2011-02-01

    In yeast, SIR2 overexpression or calorie restriction (CR) results in life-span extension. It was previously suggested that CR activates Sir2 by reducing the levels of Sir2 inhibitors, NADH, or nicotinamide. Whereas NADH reduction is associated with an increase in respiration, nicotinamide clearance is induced by the upregulation of PNC1. Here, we show that, consistent with the hormesis hypothesis, PNC1 is part of a transcriptional stress response module consisting of 39 genes that increases under various stresses. Under high CR (0.1% glucose), Pnc1 becomes activated and its levels increase. However, low CR (0.5% glucose) increases yeast life span without PNC1 induction or activation of any transcriptional stress response. Instead, microarray analysis of low CR shows that the messenger RNA levels of iron transport genes increase, suggesting that this mode of CR is regulated by a shift toward respiration and lowering NADH levels. Thus, at least two pathways regulate the CR response in yeast. PMID:21081478

  2. MicroRNAs: New Regulators of Toll-Like Receptor Signalling Pathways

    PubMed Central

    He, Xiaobing; Jing, Zhizhong; Cheng, Guofeng

    2014-01-01

    Toll-like receptors (TLRs), a critical family of pattern recognition receptors (PRRs), are responsible for the innate immune responses via signalling pathways to provide effective host defence against pathogen infections. However, TLR-signalling pathways are also likely to stringently regulate tissue maintenance and homeostasis by elaborate modulatory mechanisms. MicroRNAs (miRNAs) have emerged as key regulators and as an essential part of the networks involved in regulating TLR-signalling pathways. In this review, we highlight our understanding of the regulation of miRNA expression profiles by TLR-signalling pathways and the regulation of TLR-signalling pathways by miRNAs. We focus on the roles of miRNAs in regulating TLR-signalling pathways by targeting multiple molecules, including TLRs themselves, their associated signalling proteins and regulatory molecules, and transcription factors and functional cytokines induced by them, at multiple levels. PMID:24772440

  3. From tyrosine to melanin: Signaling pathways and factors regulating melanogenesis.

    PubMed

    Rzepka, Zuzanna; Buszman, Ewa; Beberok, Artur; Wrześniok, Dorota

    2016-01-01

    Melanins are natural pigments of skin, hair and eyes and can be classified into two main types: brown to black eumelanin and yellow to reddish-brown pheomelanin. Biosynthesis of melanins takes place in melanosomes, which are specialized cytoplasmic organelles of melanocytes - dendritic cells located in the basal layer of the epidermis, uveal tract of the eye, hair follicles, as well as in the inner ear, central nervous system and heart. Melanogenesis is a multistep process and begins with the conversion of amino acid L-tyrosine to DOPAquinone. The addition of cysteine or glutathione to DOPAquinone leads to the intermediates formation, followed by subsequent transformations and polymerization to the final product, pheomelanin. In the absence of thiol compounds DOPAquinone undergoes an intramolecular cyclization and oxidation to form DOPAchrome, which is then converted to 5,6-dihydroksyindole (DHI) or 5,6-dihydroxyindole-2-carboxylic acid (DHICA). Eumelanin is formed by polymerization of DHI and DHICA and their quinones. Regulation of melanogenesis is achieved by physical and biochemical factors. The article presents the intracellular signaling pathways: cAMP/PKA/CREB/MITF cascade, MAP kinases cascade, PLC/DAG/PKCβ cascade and NO/cGMP/PKG cascade, which are involved in the regulation of expression and activity of the melanogenesis-related proteins by ultraviolet radiation and endogenous agents (cytokines, hormones). Activity of the key melanogenic enzyme, tyrosinase, is also affected by pH and temperature. Many pharmacologically active substances are able to inhibit or stimulate melanin biosynthesis, as evidenced by in vitro studies on cultured pigment cells. PMID:27356601

  4. Trim69 regulates zebrafish brain development by ap-1 pathway

    PubMed Central

    Han, Ruiqin; Wang, Renxian; Zhao, Qing; Han, Yongqing; Zong, Shudong; Miao, Shiying; Song, Wei; Wang, Linfang

    2016-01-01

    Proteins belonging to the TRIM family have been implicated in a variety of cellular processes such as apoptosis, differentiation, neurogenesis, muscular physiology and innate immune responses. Trim69, previously identified as a novel gene cloned from a human testis cDNA library, has a homologous gene in zebrafish and this study focused on investigating the function of trim69 in zebrafish neurogenesis. Trim69 was found to be expressed in zebrafish embryo brain at the early stages. Knockdown of trim69 led to deformed brain development, obvious signs of apoptosis present in the head, and decreased expression of neuronal differentiation and stem cell markers. This phenotype was rescued upon co-injection of human mRNA together along with the trim69 knockdown. Results of this study also showed an interaction between TRIM69 and c-Jun in human cells, and upon TRIM69 knock down c-Jun expression subsequently increased, whereas the over-expression of TRIM69 led to the down-regulation of c-Jun. Additionally, knockdown both c-Jun and trim69 can rescue the deformed brain, evident cellular apoptosis in the head and decreased expression of neuronal differentiation and stem cell markers. Overall, our results support a role for trim69 in the development of the zebrafish brain through ap-1 pathway. PMID:27050765

  5. OASIS modulates hypoxia pathway activity to regulate bone angiogenesis

    PubMed Central

    Cui, Min; Kanemoto, Soshi; Cui, Xiang; Kaneko, Masayuki; Asada, Rie; Matsuhisa, Koji; Tanimoto, Keiji; Yoshimoto, Yuki; Shukunami, Chisa; Imaizumi, Kazunori

    2015-01-01

    OASIS/CREB3L1, an endoplasmic reticulum (ER)-resident transcription factor, plays important roles in osteoblast differentiation. In this study, we identified new crosstalk between OASIS and the hypoxia signaling pathway, which regulates vascularization during bone development. RT-PCR and real-time PCR analyses revealed significant decreases in the expression levels of hypoxia-inducible factor-1α (HIF-1α) target genes such as vascular endothelial growth factor A (VEGFA) in OASIS-deficient (Oasis−/−) mouse embryonic fibroblasts. In coimmunoprecipitation experiments, the N-terminal fragment of OASIS (OASIS-N; activated form of OASIS) bound to HIF-1α through the bZIP domain. Luciferase assays showed that OASIS-N promoted the transcription activities of a reporter gene via a hypoxia-response element (HRE). Furthermore, the expression levels of an angiogenic factor Vegfa was decreased in Oasis−/− osteoblasts. Immunostaining and metatarsal angiogenesis assay showed retarded vascularization in bone tissue of Oasis−/− mice. These results suggest that OASIS affects the expression of HIF-1α target genes through the protein interaction with HIF-1α, and that OASIS-HIF-1α complexes may play essential roles in angiogenesis during bone development. PMID:26558437

  6. Cinnamon polyphenols regulate multiple metabolic pathways involved in intestinal lipid metabolism of primary small intestinal enterocytes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing evidence suggests that dietary factors may affect the expression of multiple genes and signaling pathways including those that regulate intestinal lipoprotein metabolism. The small intestine is actively involved in the regulation of dietary lipid absorption, intracellular transport and me...

  7. Nrf2-driven TERT regulates pentose phosphate pathway in glioblastoma

    PubMed Central

    Ahmad, F; Dixit, D; Sharma, V; Kumar, A; Joshi, S D; Sarkar, C; Sen, E

    2016-01-01

    Given the involvement of telomerase activation and dysregulated metabolism in glioma progression, the connection between these two critical players was investigated. Pharmacological inhibition of human Telomerase reverse transcriptase (hTERT) by Costunolide induced glioma cell apoptosis in a reactive oxygen species (ROS)-dependent manner. Costunolide induced an ROS-dependent increase in p53 abrogated telomerase activity. Costunolide decreased Nrf2 level; and ectopic Nrf2 expression decreased Costunolide-induced ROS generation. While TERT knock-down abrogated Nrf2 levels, overexpression of Nrf2 increased TERT expression. Inhibition of hTERT either by Costunolide, or by siRNA or dominant-negative hTERT (DN-hTERT) abrogated (i) expression of Glucose-6-phosphate dehydrogenase (G6PD) and Transketolase (TKT) – two major nodes in the pentose phosphate (PPP) pathway; and (ii) phosphorylation of glycogen synthase (GS). hTERT knock-down decreased TKT activity and increased glycogen accumulation. Interestingly, siRNA-mediated knock-down of TKT elevated glycogen accumulation. Coherent with the in vitro findings, Costunolide reduced tumor burden in heterotypic xenograft glioma mouse model. Costunolide-treated tumors exhibited diminished TKT activity, heightened glycogen accumulation, and increased senescence. Importantly, glioblastoma multiforme (GBM) patient tumors bearing TERT promoter mutations (C228T and C250T) known to be associated with increased telomerase activity; exhibited elevated Nrf2 and TKT expression and decreased glycogen accumulation. Taken together, our findings highlight the previously unknown (i) role of telomerase in the regulation of PPP and glycogen accumulation and (ii) the involvement of Nrf2-TERT loop in maintaining oxidative defense responses in glioma cells. PMID:27148686

  8. Nrf2-driven TERT regulates pentose phosphate pathway in glioblastoma.

    PubMed

    Ahmad, F; Dixit, D; Sharma, V; Kumar, A; Joshi, S D; Sarkar, C; Sen, E

    2016-01-01

    Given the involvement of telomerase activation and dysregulated metabolism in glioma progression, the connection between these two critical players was investigated. Pharmacological inhibition of human Telomerase reverse transcriptase (hTERT) by Costunolide induced glioma cell apoptosis in a reactive oxygen species (ROS)-dependent manner. Costunolide induced an ROS-dependent increase in p53 abrogated telomerase activity. Costunolide decreased Nrf2 level; and ectopic Nrf2 expression decreased Costunolide-induced ROS generation. While TERT knock-down abrogated Nrf2 levels, overexpression of Nrf2 increased TERT expression. Inhibition of hTERT either by Costunolide, or by siRNA or dominant-negative hTERT (DN-hTERT) abrogated (i) expression of Glucose-6-phosphate dehydrogenase (G6PD) and Transketolase (TKT) - two major nodes in the pentose phosphate (PPP) pathway; and (ii) phosphorylation of glycogen synthase (GS). hTERT knock-down decreased TKT activity and increased glycogen accumulation. Interestingly, siRNA-mediated knock-down of TKT elevated glycogen accumulation. Coherent with the in vitro findings, Costunolide reduced tumor burden in heterotypic xenograft glioma mouse model. Costunolide-treated tumors exhibited diminished TKT activity, heightened glycogen accumulation, and increased senescence. Importantly, glioblastoma multiforme (GBM) patient tumors bearing TERT promoter mutations (C228T and C250T) known to be associated with increased telomerase activity; exhibited elevated Nrf2 and TKT expression and decreased glycogen accumulation. Taken together, our findings highlight the previously unknown (i) role of telomerase in the regulation of PPP and glycogen accumulation and (ii) the involvement of Nrf2-TERT loop in maintaining oxidative defense responses in glioma cells. PMID:27148686

  9. Rac1 promotes chondrogenesis by regulating STAT3 signaling pathway.

    PubMed

    Kim, Hyoin; Sonn, Jong Kyung

    2016-09-01

    The small GTPase protein Rac1 is involved in a wide range of biological processes including cell differentiation. Previously, Rac1 was shown to promote chondrogenesis in micromass cultures of limb mesenchyme. However, the pathways mediating Rac1's role in chondrogenesis are not fully understood. This study aimed to explore the molecular mechanisms by which Rac1 regulates chondrogenic differentiation. Phosphorylation of signal transducer and activator of transcription 3 (STAT3) was increased as chondrogenesis proceeded in micromass cultures of chick wing bud mesenchyme. Inhibition of Rac1 with NSC23766, janus kinase 2 (JAK2) with AG490, or STAT3 with stattic inhibited chondrogenesis and reduced phosphorylation of STAT3. Conversely, overexpression of constitutively active Rac1 (Rac L61) increased phosphorylation of STAT3. Rac L61 expression resulted in increased expression of interleukin 6 (IL-6), and treatment with IL-6 increased phosphorylation of STAT3. NSC23766, AG490, and stattic prohibited cell aggregation, whereas expression of Rac L61 increased cell aggregation, which was reduced by stattic treatment. Our studies indicate that Rac1 induces STAT3 activation through expression and action of IL-6. Overexpression of Rac L61 increased expression of bone morphogenic protein 4 (BMP4). BMP4 promoted chondrogenesis, which was inhibited by K02288, an activin receptor-like kinase-2 inhibitor, and increased phosphorylation of p38 MAP kinase. Overexpression of Rac L61 also increased phosphorylation of p38 MAPK, which was reduced by K02288. These results suggest that Rac1 activates STAT3 by expression of IL-6, which in turn increases expression and activity of BMP4, leading to the promotion of chondrogenesis. PMID:27306109

  10. Intracellular pathways regulating ciliary beating of rat brain ependymal cells

    PubMed Central

    Nguyen, Thien; Chin, Wei-Chun; O’Brien, Jennifer A; Verdugo, Pedro; Berger, Albert J

    2001-01-01

    The mammalian brain ventricles are lined with ciliated ependymal cells. As yet little is known about the mechanisms by which neurotransmitters regulate cilia beat frequency (CBF). Application of 5-HT to ependymal cells in cultured rat brainstem slices caused CBF to increase. 5-HT had an EC50 of 30 μM and at 100 μM attained a near-maximal CBF increase of 52.7 ± 4.1 % (mean ± s.d.) (n= 8). Bathing slices in Ca2+-free solution markedly reduced the 5-HT-mediated increase in CBF. Fluorescence measurements revealed that 5-HT caused a marked transient elevation in cytosolic Ca2+ ([Ca2+]c) that then slowly decreased to a plateau level. Analysis showed that the [Ca2+]c transient was due to release of Ca2+ from inositol 1,4,5-trisphosphate (IP3)-sensitive stores; the plateau was probably due to extracellular Ca2+ influx through Ca2+ release-activated Ca2+ (CRAC) channels. Application of ATP caused a sustained decrease in CBF. ATP had an EC50 of about 50 μM and 100 μM ATP resulted in a maximal 57.5 ± 6.5 % (n= 12) decrease in CBF. The ATP-induced decrease in CBF was unaffected by lowering extracellular [Ca2+], and no changes in [Ca2+]c were observed. Exposure of ependymal cells to forskolin caused a decrease in CBF. Ciliated ependymal cells loaded with caged cAMP exhibited a 54.3 ± 7.5 % (n= 9) decrease in CBF following uncaging. These results suggest that ATP reduces CBF by a Ca2+-independent cAMP-mediated pathway. Application of 5-HT and adenosine-5′-O-3-thiotriphosphate (ATP-γ-S) to acutely isolated ciliated ependymal cells resulted in CBF responses similar to those of ependymal cells in cultured slices suggesting that these neurotransmitters act directly on these cells. The opposite response of ciliated ependymal cells to 5-HT and ATP provides a novel mechanism for their active involvement in central nervous system signalling. PMID:11179397

  11. Casein kinase iepsilon in the wnt pathway: regulation of beta-catenin function.

    PubMed

    Sakanaka, C; Leong, P; Xu, L; Harrison, S D; Williams, L T

    1999-10-26

    Wnt and its intracellular effector beta-catenin regulate developmental and oncogenic processes. Using expression cloning to identify novel components of the Wnt pathway, we isolated casein kinase Iepsilon (CKIepsilon). CKIepsilon mimicked Wnt in inducing a secondary axis in Xenopus, stabilizing beta-catenin, and stimulating gene transcription in cells. Inhibition of endogenous CKIepsilon by kinase-defective CKIepsilon or CKIepsilon antisense-oligonucleotides attenuated Wnt signaling. CKIepsilon was in a complex with axin and other downstream components of the Wnt pathway, including Dishevelled. CKIepsilon appears to be a positive regulator of the pathway and a link between upstream signals and the complexes that regulate beta-catenin. PMID:10535959

  12. Adverse Outcome Pathways: From Research to Regulation - Scientific Workshop Report

    EPA Science Inventory

    An adverse outcome pathway (AOP) organizes existing knowledge on chemical mode of action, starting with a molecular initiating event such as receptor binding, continuing through key events, and ending with an adverse outcome such as reproductive impairment. AOPs can help identify...

  13. Regulation of the expression of the whole genome of Ustilago maydis by a MAPK pathway.

    PubMed

    Martínez-Soto, Domingo; Ruiz-Herrera, José

    2015-05-01

    The operation of mitogen-activated protein kinase (MAPK) signal transduction pathways is one of the most important mechanisms for the transfer of extracellular information into the cell. These pathways are highly conserved in eukaryotic organisms. In fungi, MAPK pathways are involved in the regulation of a number of cellular processes such as metabolism, homeostasis, pathogenesis and cell differentiation and morphogenesis. Considering the importance of pathways, in the present work we proceeded to identify all the genes that are regulated by the signal transduction pathway involved in mating, pathogenesis and morphogenesis of Ustilago maydis. Accordingly we made a comparison between the transcriptomes from a wild-type strain and an Ubc2 mutant affected in the interacting protein of this pathway by use of microarrays. By this methodology, we identified 939 genes regulated directly or indirectly by the MAPK pathway. Of them, 432 were positively, and 507 were negatively found regulated. By functional grouping, genes encoding cyclin-dependent kinases, transcription factors, proteins involved in signal transduction, in synthesis of wall and cell membrane, and involved in dimorphism were identified as differentially regulated. These data reveal the importance of these global studies, and the large (and unsuspected) number of functions of the fungus under the control of this MAPK, providing clues to the possible mechanisms involved. PMID:25666931

  14. The Retinoblastoma pathway regulates stem cell proliferation in freshwater planarians.

    PubMed

    Zhu, Shu Jun; Pearson, Bret J

    2013-01-15

    Freshwater planarians are flatworms of the Lophotrochozoan superphylum and are well known for their regenerative abilities, which rely on a large population of pluripotent adult stem cells. However, the mechanisms by which planarians maintain a precise population of adult stem cells while balancing proliferation and cell death, remain to be elucidated. Here we have identified, characterized, and functionally tested the core Retinoblastoma (Rb) pathway components in planarian adult stem cell biology. The Rb pathway is an ancient and conserved mechanism of proliferation control from plants to animals and is composed of three core components: an Rb protein, and a transcription factor heterodimer of E2F and DP proteins. Although the planarian genome contains all components of the Rb pathway, we found that they have undergone gene loss from the ancestral state, similar to other species in their phylum. The single Rb homolog (Smed-Rb) was highly expressed in planarian stem cells and was required for stem cell maintenance, similar to the Rb-homologs p107 and p130 in vertebrates. We show that planarians and their phylum have undergone the most severe reduction in E2F genes observed thus far, and the single remaining E2F was predicted to be a repressive-type E2F (Smed-E2F4-1). Knockdown of either Smed-E2F4-1 or its dimerization partner Dp (Smed-Dp) by RNAi resulted in temporary hyper-proliferation. Finally, we showed that known Rb-interacting genes in other systems, histone deacetylase 1 and cyclinD (Smed-HDAC1; Smed-cycD), were similar to Rb in expression and phenotypes when knocked down by RNAi, suggesting that these established interactions with Rb may also be conserved in planarians. Together, these results showed that planarians use the conserved components of the Rb tumor suppressor pathway to control proliferation and cell survival. PMID:23123964

  15. Glucose metabolism and hexosamine pathway regulate oncogene-induced senescence.

    PubMed

    Gitenay, D; Wiel, C; Lallet-Daher, H; Vindrieux, D; Aubert, S; Payen, L; Simonnet, H; Bernard, D

    2014-01-01

    Oncogenic stress-induced senescence (OIS) prevents the ability of oncogenic signals to induce tumorigenesis. It is now largely admitted that the mitogenic effect of oncogenes requires metabolic adaptations to respond to new energetic and bio constituent needs. Yet, whether glucose metabolism affects OIS response is largely unknown. This is largely because of the fact that most of the OIS cellular models are cultivated in glucose excess. In this study, we used human epithelial cells, cultivated without glucose excess, to study alteration and functional role of glucose metabolism during OIS. We report a slowdown of glucose uptake and metabolism during OIS. Increasing glucose metabolism by expressing hexokinase2 (HK2), which converts glucose to glucose-6-phosphate (G6P), favors escape from OIS. Inversely, expressing a glucose-6-phosphatase, [corrected] pharmacological inhibition of HK2, or adding nonmetabolizable glucose induced a premature senescence. Manipulations of various metabolites covering G6P downstream pathways (hexosamine, glycolysis, and pentose phosphate pathways) suggest an unexpected role of the hexosamine pathway in controlling OIS. Altogether, our results show that decreased glucose metabolism occurs during and participates to OIS. PMID:24577087

  16. Post-Transcriptional Regulation of Interferons and Their Signaling Pathways

    PubMed Central

    2014-01-01

    Interferons (IFNs) are low molecular weight cell-derived proteins that include the type I, II, and III IFN families. IFNs are critical for an optimal immune response during microbial infections while dysregulated expression can lead to autoimmune diseases. Given its role in disease, it is important to understand cellular mechanisms of IFN regulation. 3′ untranslated regions (3′ UTRs) have emerged as potent regulators of mRNA and protein dosage and are controlled through multiple regulatory elements including adenylate uridylate (AU)-rich elements (AREs) and microRNA (miRNA) recognition elements. These AREs are targeted by RNA-binding proteins (ARE-BPs) for degradation and/or stabilization through an ARE-mediated decay process. miRNA are endogenous, single-stranded RNA molecules ∼22 nucleotides in length that regulate mRNA translation through the miRNA-induced silencing complex. IFN transcripts, like other labile mRNAs, harbor AREs in their 3′ UTRs that dictate the turnover of mRNA. This review is a survey of the literature related to IFN regulation by miRNA, ARE-BPs, and how these complexes interact dynamically on the 3′ UTR. Additionally, downstream effects of these post-transcriptional regulators on the immune response will be discussed. Review topics include past studies, current understanding, and future challenges in the study of post-transcriptional regulation affecting IFN responses. PMID:24702117

  17. Influence maximization in time bounded network identifies transcription factors regulating perturbed pathways

    PubMed Central

    Jo, Kyuri; Jung, Inuk; Moon, Ji Hwan; Kim, Sun

    2016-01-01

    Motivation: To understand the dynamic nature of the biological process, it is crucial to identify perturbed pathways in an altered environment and also to infer regulators that trigger the response. Current time-series analysis methods, however, are not powerful enough to identify perturbed pathways and regulators simultaneously. Widely used methods include methods to determine gene sets such as differentially expressed genes or gene clusters and these genes sets need to be further interpreted in terms of biological pathways using other tools. Most pathway analysis methods are not designed for time series data and they do not consider gene-gene influence on the time dimension. Results: In this article, we propose a novel time-series analysis method TimeTP for determining transcription factors (TFs) regulating pathway perturbation, which narrows the focus to perturbed sub-pathways and utilizes the gene regulatory network and protein–protein interaction network to locate TFs triggering the perturbation. TimeTP first identifies perturbed sub-pathways that propagate the expression changes along the time. Starting points of the perturbed sub-pathways are mapped into the network and the most influential TFs are determined by influence maximization technique. The analysis result is visually summarized in TF-Pathway map in time clock. TimeTP was applied to PIK3CA knock-in dataset and found significant sub-pathways and their regulators relevant to the PIP3 signaling pathway. Availability and Implementation: TimeTP is implemented in Python and available at http://biohealth.snu.ac.kr/software/TimeTP/. Supplementary information: Supplementary data are available at Bioinformatics online. Contact: sunkim.bioinfo@snu.ac.kr PMID:27307609

  18. Reconstitution of the Cytoplasmic Regulation of the Wnt Signaling Pathway Using Xenopus Egg Extracts.

    PubMed

    Hyde, Annastasia Simone; Hang, Brian I; Lee, Ethan

    2016-01-01

    The regulation of β-catenin turnover is the central mechanism governing activation of the Wnt signaling pathway. All components of the pathway are present in the early embryo of Xenopus laevis, and Xenopus egg extracts have been used to recapitulate complex biological reactions such as microtubule dynamics, DNA replication, chromatin assembly, and phases of the cell cycle. Herein, we describe a biochemical method for analyzing β-catenin degradation using radiolabeled and luciferase-fusion proteins in Xenopus egg extracts. We show that in such a biochemical system, cytoplasmic β-catenin degradation is regulated by soluble components of the Wnt pathway as well as small molecules. PMID:27590156

  19. Pathway Regulation of p63, a Director of Epithelial Cell Fate

    PubMed Central

    Yoh, Kathryn; Prywes, Ron

    2015-01-01

    The p53-related gene p63 is required for epithelial cell establishment and its expression is often altered in tumor cells. Great strides have been made in understanding the pathways and mechanisms that regulate p63 levels, such as the Wnt, Hedgehog, Notch, and EGFR pathways. We discuss here the multiple signaling pathways that control p63 expression as well as transcription factors and post-transcriptional mechanisms that regulate p63 levels. While a unified picture has not emerged, it is clear that the fine-tuning of p63 has evolved to carefully control epithelial cell differentiation and fate. PMID:25972840

  20. Regulation of different inflammatory diseases by impacting the mevalonate pathway

    PubMed Central

    Zeiser, Robert; Maas, Kristina; Youssef, Sawsan; Dürr, Christoph; Steinman, Lawrence; Negrin, Robert S

    2009-01-01

    The 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase inhibitors (statins) interfere with the mevalonate pathway. While initially developed for their lipid-lowering properties, statins have been extensively investigated with respect to their impact on autoantigen and alloantigen driven immune responses. Mechanistically it was shown that statins modify immune responses on several levels, including effects on dendritic cells, endothelial cells, macrophages, B cells and T cells. Several lines of evidence suggest that statins act in a disease-specific manner and are not effective in each immune disorder. This review discusses possible modes of action of statins in modulating immunity towards autoantigens and alloantigens. PMID:19191903

  1. Method to determine transcriptional regulation pathways in organisms

    DOEpatents

    Gardner, Timothy S.; Collins, James J.; Hayete, Boris; Faith, Jeremiah

    2012-11-06

    The invention relates to computer-implemented methods and systems for identifying regulatory relationships between expressed regulating polypeptides and targets of the regulatory activities of such regulating polypeptides. More specifically, the invention provides a new method for identifying regulatory dependencies between biochemical species in a cell. In particular embodiments, provided are computer-implemented methods for identifying a regulatory interaction between a transcription factor and a gene target of the transcription factor, or between a transcription factor and a set of gene targets of the transcription factor. Further provided are genome-scale methods for predicting regulatory interactions between a set of transcription factors and a corresponding set of transcriptional target substrates thereof.

  2. Transcriptomic analysis in the developing zebrafish embryo after compound exposure: Individual gene expression and pathway regulation

    SciTech Connect

    Hermsen, Sanne A.B.; Pronk, Tessa E.; Brandhof, Evert-Jan van den; Ven, Leo T.M. van der; Piersma, Aldert H.

    2013-10-01

    The zebrafish embryotoxicity test is a promising alternative assay for developmental toxicity. Classically, morphological assessment of the embryos is applied to evaluate the effects of compound exposure. However, by applying differential gene expression analysis the sensitivity and predictability of the test may be increased. For defining gene expression signatures of developmental toxicity, we explored the possibility of using gene expression signatures of compound exposures based on commonly expressed individual genes as well as based on regulated gene pathways. Four developmental toxic compounds were tested in concentration-response design, caffeine, carbamazepine, retinoic acid and valproic acid, and two non-embryotoxic compounds, D-mannitol and saccharin, were included. With transcriptomic analyses we were able to identify commonly expressed genes, which were mostly development related, after exposure to the embryotoxicants. We also identified gene pathways regulated by the embryotoxicants, suggestive of their modes of action. Furthermore, whereas pathways may be regulated by all compounds, individual gene expression within these pathways can differ for each compound. Overall, the present study suggests that the use of individual gene expression signatures as well as pathway regulation may be useful starting points for defining gene biomarkers for predicting embryotoxicity. - Highlights: • The zebrafish embryotoxicity test in combination with transcriptomics was used. • We explored two approaches of defining gene biomarkers for developmental toxicity. • Four compounds in concentration-response design were tested. • We identified commonly expressed individual genes as well as regulated gene pathways. • Both approaches seem suitable starting points for defining gene biomarkers.

  3. Soil formate regulates the fungal nitrous oxide emission pathway.

    PubMed

    Ma, W K; Farrell, R E; Siciliano, S D

    2008-11-01

    Fungal activity is a major driver in the global nitrogen cycle, and mounting evidence suggests that fungal denitrification activity contributes significantly to soil emissions of the greenhouse gas nitrous oxide (N(2)O). The metabolic pathway and oxygen requirement for fungal denitrification are different from those for bacterial denitrification. We hypothesized that the soil N(2)O emission from fungi is formate and O(2) dependent and that land use and landforms could influence the proportion of N(2)O coming from fungi. Using substrate-induced respiration inhibition under anaerobic and aerobic conditions in combination with (15)N gas analysis, we found that formate and hypoxia (versus anaerobiosis) were essential for the fungal reduction of (15)N-labeled nitrate to (15)N(2)O. As much as 65% of soil-emitted N(2)O was attributable to fungi; however, this was found only in soils from water-accumulating landforms. From these results, we hypothesize that plant root exudates could affect N(2)O production from fungi via the proposed formate-dependent pathway. PMID:18791019

  4. Developmental Pathways of Emotion Regulation in Childhood: A Neuropsychological Perspective

    ERIC Educational Resources Information Center

    Woltering, Steven; Lewis, Marc D.

    2009-01-01

    This article presents a model featuring two types of emotion regulation--reactive and deliberate--and discusses the developmental trajectory of both types. We argue that the later-developing capacity for deliberate control builds on and coevolves with earlier-developing reactive control. Findings from the field of developmental neuroscience are…

  5. IL-1α Counteract TGF-β Regulated Genes and Pathways in Human Fibroblasts.

    PubMed

    Koskela von Sydow, Anita; Janbaz, Chris; Kardeby, Caroline; Repsilber, Dirk; Ivarsson, Mikael

    2016-07-01

    Dysregulated wound healing is commonly associated with excessive fibrosis. Connective tissue growth factor (CTGF/CCN2) is characteristically overexpressed in fibrotic diseases and stimulated by transforming growth factor-β (TGF-β) in dermal fibroblasts. We previously showed that interleukin-1 (IL-1α) counteracts TGF-β-stimulated CTGF mRNA and protein expression in these cells. The aim of this study was to explore the effects of IL-1α on further genes and pathways in TGF-β regulated fibroblasts. Transcriptional microarray and multiple comparison analysis showed that the antagonizing effects of IL-1α was much more prominent than the synergistic effects, both with respect to number of genes and extent of changes in gene expression. Moreover, comparing canonical pathways by gene set enrichment analysis and the Ingenuity Pathway Analysis tool revealed that IL-1α counteracted TGF-β in the top six most confident pathways regulated by both cytokines. Interferon and IL-1 signaling, as well as two pathways involved in apoptosis signaling were suppressed by TGF-β and activated by IL-1α. Pathways involving actin remodeling and focal adhesion dynamics were activated by TGF-β and suppressed by IL-1α. Analyzing upstream regulators in part corroborate the comparison of canonical pathways and added cell cycle regulators as another functional group regulated by IL-1α. Finally, gene set enrichment analysis of fibrosis-related genes indicated that IL-1 moderately counteracts the collective effect of TGF-β on these genes. Microarray results were validated by qPCR. Taken together, the results indicate prominent antagonistic effects of IL-1α on TGF-β regulated interferon signaling, as well as on a wide variety of other genes and pathways in fibroblasts. J. Cell. Biochem. 117: 1622-1632, 2016. © 2015 Wiley Periodicals, Inc. PMID:26629874

  6. Biochemical pathways that regulate acetyltransferase and deacetylase activity in mammalian cells

    PubMed Central

    Mellert, Hestia S.; McMahon, Steven B.

    2009-01-01

    Protein phosphorylation is dynamically regulated in eukaryotic cells via modulation of the enzymatic activity of kinases and phosphatases. Like phosphorylation, acetylation has emerged as a critical regulatory protein modification that is dynamically altered in response to diverse cellular cues. Moreover, acetyltransferases and deacetylases are tightly linked to cellular signaling pathways. Recent studies provide clues about the mechanisms utilized to regulate acetyltransferases and deacetylases. The therapeutic value of deacetylase inhibitors suggests that understanding acetylation pathways will directly impact our ability to rationally target these enzymes in patients. Recently discovered mechanisms which directly regulate the catalytic activity of acetyltransferases and deacetylases provide exciting new insights about these enzymes. PMID:19819149

  7. Mechanisms and pathways of innate immune activation and regulation in health and cancer

    PubMed Central

    Cui, Jun; Chen, Yongjun; Wang, Helen Y; Wang, Rong-Fu

    2015-01-01

    Research on innate immune signaling and regulation has recently focused on pathogen recognition receptors (PRRs) and their signaling pathways. Members of PRRs sense diverse microbial invasions or danger signals, and initiate innate immune signaling pathways, leading to proinflammatory cytokines production, which, in turn, instructs adaptive immune response development. Despite the diverse functions employed by innate immune signaling to respond to a variety of different pathogens, the innate immune response must be tightly regulated. Otherwise, aberrant, uncontrolled immune responses will lead to harmful, or even fatal, consequences. Therefore, it is essential to better discern innate immune signaling and many regulators, controlling various signaling pathways, have been identified. In this review, we focus on the recent advances in our understanding of the activation and regulation of innate immune signaling in the host response to pathogens and cancer. PMID:25625930

  8. Mechanisms and pathways of innate immune activation and regulation in health and cancer.

    PubMed

    Cui, Jun; Chen, Yongjun; Wang, Helen Y; Wang, Rong-Fu

    2014-01-01

    Research on innate immune signaling and regulation has recently focused on pathogen recognition receptors (PRRs) and their signaling pathways. Members of PRRs sense diverse microbial invasions or danger signals, and initiate innate immune signaling pathways, leading to proinflammatory cytokines production, which, in turn, instructs adaptive immune response development. Despite the diverse functions employed by innate immune signaling to respond to a variety of different pathogens, the innate immune response must be tightly regulated. Otherwise, aberrant, uncontrolled immune responses will lead to harmful, or even fatal, consequences. Therefore, it is essential to better discern innate immune signaling and many regulators, controlling various signaling pathways, have been identified. In this review, we focus on the recent advances in our understanding of the activation and regulation of innate immune signaling in the host response to pathogens and cancer. PMID:25625930

  9. SETDB1 accelerates tumorigenesis by regulating WNT signaling pathway

    PubMed Central

    Sun, Qiao-Yang; Ding, Ling-Wen; Xiao, Jin-Fen; Chien, Wenwen; Lim, Su-Lin; Hattori, Norimichi; Goodglick, Lee; Chia, David; Mah, Vei; Alavi, Mohammad; Kim, Sara R.; Doan, Ngan B.; Said, Jonathan W.; Loh, Xin-Yi; Xu, Liang; Liu, Li-Zhen; Yang, Henry; Hayano, Takahide; Shi, Shuo; Xie, Dong; Lin, De-Chen; Koeffler, H. Phillip

    2014-01-01

    We investigated the oncogenic role of SETDB1 focusing on non-small cell lung cancer (NSCLC) having high expression of this protein. A total of 387 lung cancer cases were examined by immunohistochemistry, 72% of NSCLC samples were positive for SETDB1 staining, compared to 46% samples of normal bronchial epithelium (106 cases) (p<0.0001). Percent positive cells and intensity of staining increased significantly with increased grade of disease. Forced expression of SETDB1 in NSCLC cell lines enhanced their clonogenic growth in vitro and markedly increased tumor size in a murine xenograft model; while silencing (shRNA) SETDB1 in NSCLC cells slowed their proliferation. SETDB1 positively stimulated activity of the WNT/β-catenin pathway and diminished P53 expression resulting in enhanced NSCLC growth in vitro and in vivo. Our finding suggests therapeutic targeting SETDB1 may benefit patients whose tumors express high levels of SETDB1. PMID:25404354

  10. Nitrogen regulates CRY1 phosphorylation and circadian clock input pathways.

    PubMed

    Zhou, Yang-Hong; Zhang, Zhong-Wei; Zheng, Chong; Yuan, Shu; He, Yikun

    2016-09-01

    The delayed flowering phenotype caused by nitrogen (N) fertilizer application has been known for a long time, but we know little about the specific molecular mechanism for this phenomenon before. Our study indicated that low nitrogen increases the NADPH/NADP(+) and ATP/AMP ratios which affect adenosine monophosphate-activated protein kinase (AMPK) activity and phosphorylation and abundance of nuclear CRY1 protein. Then CRY1 acts in the N signal input pathway to the circadian clock. Here we further discuss: (1) the role of C/N ratio in flowering, (2) circadian oscillation of plant AMPK transcripts and proteins, (3) conservation of nutrition-mediated CRY1 phosphorylation and degradation, and (4) crosstalks between nitrogen signals and nitric oxide (NO) signals in flowering. PMID:27617369

  11. Chemical regulation of signaling pathways to programmed necrosis.

    PubMed

    Bae, Ji Hyun; Shim, Jung-Hyun; Cho, Young Sik

    2014-06-01

    Necroptosis is an active and well-orchestrated necrosis, distinctive from apoptosis in microscopic structure, and biochemical and molecular features. Unlike apoptosis-undergoing cells, which are removed by macrophage or neighboring cells, necrotic cell death releases danger signals and provokes inflammation, and further a severe damage to neighbor tissue. A regulated necrosis, termed as necroptosis or programmed necrosis, is emerging as a new paradigm of cell death that can be activated when apoptotic machinery is genetically or pathogenically defective. It plays biological significances in pathogenesis of a variety of inflammatory diseases as well as in a beneficial innate immune defense mechanism. This review highlights the identification of hits against necroptosis, and comprehensive approaches to discovery of small molecules that regulate necroptotic cell death. Also, the signaling molecular mechanism of necroptosis and future clinical uses of necroptosis inhibitor will be described in brief. PMID:24715577

  12. A Rule-Based Framework for Gene Regulation Pathways Discovery

    SciTech Connect

    Wilczynski, B; Hvidsten, T; Kryshtafovych, A; Stubbs, L; Komorowski, J; Fidelis, K

    2003-07-21

    We present novel approach to discover the rules that govern gene regulation mechanisms. The method is based on supervised machine learning and is designed to reveal relationships between transcription factors and gene promoters. As the representation of the gene regulatory circuit we have chosen a special form of IF-THEN rules associating certain features (a generalized idea of a Transcription Factor Binding Site) in gene promoters with specific gene expression profiles.

  13. A sugar phosphatase regulates the methylerythritol phosphate (MEP) pathway in malaria parasites

    PubMed Central

    Edwards, Rachel L.; Kelly, Megan L.; Hodge, Dana M.; Tolia, Niraj H.; Odom, Audrey R.

    2014-01-01

    Isoprenoid biosynthesis through the methylerythritol phosphate (MEP) pathway generates commercially important products and is a target for antimicrobial drug development. MEP pathway regulation is poorly understood in microorganisms. We employ a forward genetics approach to understand MEP pathway regulation in the malaria parasite, Plasmodium falciparum. The antimalarial fosmidomycin inhibits the MEP pathway enzyme deoxyxylulose 5-phosphate reductoisomerase (DXR). Fosmidomycin-resistant P. falciparum are enriched for changes in the PF3D7_1033400 locus (hereafter referred to as PfHAD1), encoding a homologue of haloacid dehalogenase (HAD)-like sugar phosphatases. We describe the structural basis for loss-of-function PfHAD1 alleles and find that PfHAD1 dephosphorylates a variety of sugar phosphates, including glycolytic intermediates. Loss of PfHAD1 is required for fosmidomycin resistance. Parasites lacking PfHAD1 have increased MEP pathway metabolites, particularly the DXR substrate, deoxyxylulose 5-phosphate. PfHAD1 therefore controls substrate availability to the MEP pathway. Because PfHAD1 has homologs in plants and bacteria, other HAD proteins may be MEP pathway regulators. PMID:25058848

  14. A sugar phosphatase regulates the methylerythritol phosphate (MEP) pathway in malaria parasites.

    PubMed

    Guggisberg, Ann M; Park, Jooyoung; Edwards, Rachel L; Kelly, Megan L; Hodge, Dana M; Tolia, Niraj H; Odom, Audrey R

    2014-01-01

    Isoprenoid biosynthesis through the methylerythritol phosphate (MEP) pathway generates commercially important products and is a target for antimicrobial drug development. MEP pathway regulation is poorly understood in microorganisms. Here we employ a forward genetics approach to understand MEP pathway regulation in the malaria parasite, Plasmodium falciparum. The antimalarial fosmidomycin inhibits the MEP pathway enzyme deoxyxylulose 5-phosphate reductoisomerase (DXR). Fosmidomycin-resistant P. falciparum are enriched for changes in the PF3D7_1033400 locus (hereafter referred to as PfHAD1), encoding a homologue of haloacid dehalogenase (HAD)-like sugar phosphatases. We describe the structural basis for loss-of-function PfHAD1 alleles and find that PfHAD1 dephosphorylates a variety of sugar phosphates, including glycolytic intermediates. Loss of PfHAD1 is required for fosmidomycin resistance. Parasites lacking PfHAD1 have increased MEP pathway metabolites, particularly the DXR substrate, deoxyxylulose 5-phosphate. PfHAD1 therefore controls substrate availability to the MEP pathway. Because PfHAD1 has homologues in plants and bacteria, other HAD proteins may be MEP pathway regulators. PMID:25058848

  15. Regulation of Natural mRNAs by the Nonsense-Mediated mRNA Decay Pathway

    PubMed Central

    Peccarelli, Megan

    2014-01-01

    The nonsense-mediated mRNA decay (NMD) pathway is a specialized mRNA degradation pathway that degrades select mRNAs. This pathway is conserved in all eukaryotes examined so far, and it triggers the degradation of mRNAs that prematurely terminate translation. Originally identified as a pathway that degrades mRNAs with premature termination codons as a result of errors during transcription, splicing, or damage to the mRNA, NMD is now also recognized as a pathway that degrades some natural mRNAs. The degradation of natural mRNAs by NMD has been identified in multiple eukaryotes, including Saccharomyces cerevisiae, Drosophila melanogaster, Arabidopsis thaliana, and humans. S. cerevisiae is used extensively as a model to study natural mRNA regulation by NMD. Inactivation of the NMD pathway in S. cerevisiae affects approximately 10% of the transcriptome. Similar percentages of natural mRNAs in the D. melanogaster and human transcriptomes are also sensitive to the pathway, indicating that NMD is important for the regulation of gene expression in multiple organisms. NMD can either directly or indirectly regulate the decay rate of natural mRNAs. Direct NMD targets possess NMD-inducing features. This minireview focuses on the regulation of natural mRNAs by the NMD pathway, as well as the features demonstrated to target these mRNAs for decay by the pathway in S. cerevisiae. We also compare NMD-targeting features identified in S. cerevisiae with known NMD-targeting features in other eukaryotic organisms. PMID:25038084

  16. Negative regulation of DAB2IP by Akt and SCFFbw7 pathways

    PubMed Central

    Inuzuka, Hiroyuki

    2014-01-01

    Deletion of ovarian carcinoma 2/disabled homolog 2 (DOC-2/DAB2) interacting protein (DAB2IP), is a tumor suppressor that serves as a scaffold protein involved in coordinately regulating cell proliferation, survival and apoptotic pathways. DAB2IP is epigenetically down-regulated in a variety of tumors through the action of the histone methyltransferase EZH2. Although DAB2IP is transcriptionally down-regulated in a variety of tumors, it remains unclear if other mechanisms contribute to functional inactivation of DAB2IP. Here we demonstrate that DAB2IP can be functionally down-regulated by two independent mechanisms. First, we identified that Akt1 can phosphorylate DAB2IP on S847, which regulates the interaction between DAB2IP and its effector molecules H-Ras and TRAF2. Second, we demonstrated that DAB2IP can be degraded in part through ubiquitin-proteasome pathway by SCFFbw7. DAB2IP harbors two Fbw7 phosho-degron motifs, which can be regulated by the kinase, CK1δ. Our data hence indicate that in addition to epigenetic down-regulation, two additional pathways can functional inactivate DAB2IP. Given that DAB2IP has previously been identified to possess direct causal role in tumorigenesis and metastasis, our data indicate that a variety of pathways may pass through DAB2IP to govern cancer development, and therefore highlight DAB2IP agonists as potential therapeutic approaches for future anti-cancer drug development. PMID:24912918

  17. Carbohydrate Metabolism in Archaea: Current Insights into Unusual Enzymes and Pathways and Their Regulation

    PubMed Central

    Esser, Dominik; Rauch, Bernadette

    2014-01-01

    SUMMARY The metabolism of Archaea, the third domain of life, resembles in its complexity those of Bacteria and lower Eukarya. However, this metabolic complexity in Archaea is accompanied by the absence of many “classical” pathways, particularly in central carbohydrate metabolism. Instead, Archaea are characterized by the presence of unique, modified variants of classical pathways such as the Embden-Meyerhof-Parnas (EMP) pathway and the Entner-Doudoroff (ED) pathway. The pentose phosphate pathway is only partly present (if at all), and pentose degradation also significantly differs from that known for bacterial model organisms. These modifications are accompanied by the invention of “new,” unusual enzymes which cause fundamental consequences for the underlying regulatory principles, and classical allosteric regulation sites well established in Bacteria and Eukarya are lost. The aim of this review is to present the current understanding of central carbohydrate metabolic pathways and their regulation in Archaea. In order to give an overview of their complexity, pathway modifications are discussed with respect to unusual archaeal biocatalysts, their structural and mechanistic characteristics, and their regulatory properties in comparison to their classic counterparts from Bacteria and Eukarya. Furthermore, an overview focusing on hexose metabolic, i.e., glycolytic as well as gluconeogenic, pathways identified in archaeal model organisms is given. Their energy gain is discussed, and new insights into different levels of regulation that have been observed so far, including the transcript and protein levels (e.g., gene regulation, known transcription regulators, and posttranslational modification via reversible protein phosphorylation), are presented. PMID:24600042

  18. The GOLPH3 pathway regulates Golgi shape and function and is activated by DNA damage

    PubMed Central

    Buschman, Matthew D.; Xing, Mengke; Field, Seth J.

    2015-01-01

    The Golgi protein GOLPH3 binds to PtdIns(4)P and MYO18A, linking the Golgi to the actin cytoskeleton. The GOLPH3 pathway is essential for vesicular trafficking from the Golgi to the plasma membrane. A side effect of GOLPH3-dependent trafficking is to generate the extended ribbon shape of the Golgi. Perturbation of the pathway results in changes to both Golgi morphology and secretion, with functional consequences for the cell. The cellular response to DNA damage provides an example of GOLPH3-mediated regulation of the Golgi. Upon DNA damage, DNA-PK phosphorylation of GOLPH3 increases binding to MYO18A, activating the GOLPH3 pathway, which consequently results in Golgi fragmentation, reduced trafficking, and enhanced cell survival. The PtdIns(4)P/GOLPH3/MYO18A/F-actin pathway provides new insight into the relationship between Golgi morphology and function, and their regulation. PMID:26500484

  19. Integrated pathway-based transcription regulation network mining and visualization based on gene expression profiles.

    PubMed

    Kibinge, Nelson; Ono, Naoaki; Horie, Masafumi; Sato, Tetsuo; Sugiura, Tadao; Altaf-Ul-Amin, Md; Saito, Akira; Kanaya, Shigehiko

    2016-06-01

    Conventionally, workflows examining transcription regulation networks from gene expression data involve distinct analytical steps. There is a need for pipelines that unify data mining and inference deduction into a singular framework to enhance interpretation and hypotheses generation. We propose a workflow that merges network construction with gene expression data mining focusing on regulation processes in the context of transcription factor driven gene regulation. The pipeline implements pathway-based modularization of expression profiles into functional units to improve biological interpretation. The integrated workflow was implemented as a web application software (TransReguloNet) with functions that enable pathway visualization and comparison of transcription factor activity between sample conditions defined in the experimental design. The pipeline merges differential expression, network construction, pathway-based abstraction, clustering and visualization. The framework was applied in analysis of actual expression datasets related to lung, breast and prostrate cancer. PMID:27064123

  20. Role of bile acids in the regulation of the metabolic pathways

    PubMed Central

    Taoka, Hiroki; Yokoyama, Yoko; Morimoto, Kohkichi; Kitamura, Naho; Tanigaki, Tatsuya; Takashina, Yoko; Tsubota, Kazuo; Watanabe, Mitsuhiro

    2016-01-01

    Recent studies have revealed that bile acids (BAs) are not only facilitators of dietary lipid absorption but also important signaling molecules exerting multiple physiological functions. Some major signaling pathways involving the nuclear BAs receptor farnesoid X receptor and the G protein-coupled BAs receptor TGR5/M-BAR have been identified to be the targets of BAs. BAs regulate their own homeostasis via signaling pathways. BAs also affect diverse metabolic pathways including glucose metabolism, lipid metabolism and energy expenditure. This paper suggests the mechanism of controlling metabolism via BA signaling and demonstrates that BA signaling is an attractive therapeutic target of the metabolic syndrome. PMID:27433295

  1. Role of bile acids in the regulation of the metabolic pathways.

    PubMed

    Taoka, Hiroki; Yokoyama, Yoko; Morimoto, Kohkichi; Kitamura, Naho; Tanigaki, Tatsuya; Takashina, Yoko; Tsubota, Kazuo; Watanabe, Mitsuhiro

    2016-07-10

    Recent studies have revealed that bile acids (BAs) are not only facilitators of dietary lipid absorption but also important signaling molecules exerting multiple physiological functions. Some major signaling pathways involving the nuclear BAs receptor farnesoid X receptor and the G protein-coupled BAs receptor TGR5/M-BAR have been identified to be the targets of BAs. BAs regulate their own homeostasis via signaling pathways. BAs also affect diverse metabolic pathways including glucose metabolism, lipid metabolism and energy expenditure. This paper suggests the mechanism of controlling metabolism via BA signaling and demonstrates that BA signaling is an attractive therapeutic target of the metabolic syndrome. PMID:27433295

  2. Adaptive Control Model Reveals Systematic Feedback and Key Molecules in Metabolic Pathway Regulation

    PubMed Central

    Moffitt, Richard A.; Merrill, Alfred H.; Wang, May D.

    2011-01-01

    Abstract Robust behavior in metabolic pathways resembles stabilized performance in systems under autonomous control. This suggests we can apply control theory to study existing regulation in these cellular networks. Here, we use model-reference adaptive control (MRAC) to investigate the dynamics of de novo sphingolipid synthesis regulation in a combined theoretical and experimental case study. The effects of serine palmitoyltransferase over-expression on this pathway are studied in vitro using human embryonic kidney cells. We report two key results from comparing numerical simulations with observed data. First, MRAC simulations of pathway dynamics are comparable to simulations from a standard model using mass action kinetics. The root-sum-square (RSS) between data and simulations in both cases differ by less than 5%. Second, MRAC simulations suggest systematic pathway regulation in terms of adaptive feedback from individual molecules. In response to increased metabolite levels available for de novo sphingolipid synthesis, feedback from molecules along the main artery of the pathway is regulated more frequently and with greater amplitude than from other molecules along the branches. These biological insights are consistent with current knowledge while being new that they may guide future research in sphingolipid biology. In summary, we report a novel approach to study regulation in cellular networks by applying control theory in the context of robust metabolic pathways. We do this to uncover potential insight into the dynamics of regulation and the reverse engineering of cellular networks for systems biology. This new modeling approach and the implementation routines designed for this case study may be extended to other systems. Supplementary Material is available at www.liebertonline.com/cmb. PMID:21314456

  3. Regulation of convergence and extension movements during vertebrate gastrulation by the Wnt/PCP pathway

    PubMed Central

    Roszko, Isabelle; Sawada, Atsushi; Solnica-Krezel, Lilianna

    2009-01-01

    Vertebrate gastrulation entails massive cell movements that establish and shape the germ layers. During gastrulation, the individual cell behaviors are strictly coordinated in time and space by various signaling pathways. These pathways instruct the cells about proliferation, shape, fate and migration into proper location. Convergence and extension (C&E) movements during vertebrate gastrulation play a major role in the shaping of the embryonic body. In vertebrates, the Wnt/Planar Cell Polarity (Wnt/PCP) pathway is a key regulator of C&E movements, essential for several polarized cell behaviors, including directed cell migration, and mediolateral and radial cell intercalation. However, the molecular mechanisms underlying the acquisition of planar cell polarity by highly dynamic mesenchymal cells engaged in C&E is still not well understood. Each cell in the embryo needs spatial and temporal information, which are required for its appropriate behavior, and the Wnt/PCP pathway provides this information by a yet unclear mechanism. Here we review new evidence implicating the Wnt/PCP pathway in specific cell behaviors required for C&E during zebrafish gastrulation, in comparison to other vertebrates. We also discuss findings on the molecular regulation and the interaction of the Wnt/PCP pathway with other signaling pathways during gastrulation movements. PMID:19761865

  4. Regulation of lifespan in Drosophila by modulation of genes in the TOR signaling pathway.

    PubMed

    Kapahi, Pankaj; Zid, Brian M; Harper, Tony; Koslover, Daniel; Sapin, Viveca; Benzer, Seymour

    2004-05-25

    In many species, reducing nutrient intake without causing malnutrition extends lifespan. Like DR (dietary restriction), modulation of genes in the insulin-signaling pathway, known to alter nutrient sensing, has been shown to extend lifespan in various species. In Drosophila, the target of rapamycin (TOR) and the insulin pathways have emerged as major regulators of growth and size. Hence we examined the role of TOR pathway genes in regulating lifespan by using Drosophila. We show that inhibition of TOR signaling pathway by alteration of the expression of genes in this nutrient-sensing pathway, which is conserved from yeast to human, extends lifespan in a manner that may overlap with known effects of dietary restriction on longevity. In Drosophila, TSC1 and TSC2 (tuberous sclerosis complex genes 1 and 2) act together to inhibit TOR (target of rapamycin), which mediates a signaling pathway that couples amino acid availability to S6 kinase, translation initiation, and growth. We find that overexpression of dTsc1, dTsc2, or dominant-negative forms of dTOR or dS6K all cause lifespan extension. Modulation of expression in the fat is sufficient for the lifespan-extension effects. The lifespan extensions are dependent on nutritional condition, suggesting a possible link between the TOR pathway and dietary restriction. PMID:15186745

  5. Regulation of Lifespan in Drosophila by Modulation of Genes in the TOR Signaling Pathway

    PubMed Central

    Kapahi, Pankaj; Zid, Brian M.; Harper, Tony; Koslover, Daniel; Sapin, Viveca; Benzer, Seymour

    2009-01-01

    Summary In many species, reducing nutrient intake without causing malnutrition extends lifespan [1-3]. Like DR (dietary restriction), modulation of genes in the insulin-signaling pathway, known to alter nutrient sensing, has been shown to extend lifespan in various species [1-4]. In Drosophila, the target of rapamycin (TOR) and the insulin pathways have emerged as major regulators of growth and size. Hence we examined the role of TOR pathway genes in regulating lifespan by using Drosophila. We show that inhibition of TOR signaling pathway by alteration of the expression of genes in this nutrient-sensing pathway, which is conserved from yeast to human, extends lifespan in a manner that may overlap with known effects of dietary restriction on longevity. In Drosophila , TSC1 and TSC2 (tuberous sclerosis complex genes 1 and 2) act together to inhibit TOR (target of rapamycin), which mediates a signaling pathway that couples amino acid availability to S6 kinase, translation initiation, and growth [5]. We find that overexpression of dTsc1, dTsc2, or dominant-negative forms of dTOR or dS6K all cause lifespan extension. Modulation of expression in the fat is sufficient for the lifespan-extension effects. The lifespan extensions are dependent on nutritional condition, suggesting a possible link between the TOR pathway and dietary restriction. PMID:15186745

  6. Ken & barbie selectively regulates the expression of a subset of Jak/STAT pathway target genes.

    PubMed

    Arbouzova, Natalia I; Bach, Erika A; Zeidler, Martin P

    2006-01-10

    A limited number of evolutionarily conserved signal transduction pathways are repeatedly reused during development to regulate a wide range of processes. Here we describe a new negative regulator of JAK/STAT signaling and identify a potential mechanism by which the pleiotropy of responses resulting from pathway activation is generated in vivo. As part of a genetic interaction screen, we have identified Ken & Barbie (Ken) , which is an ortholog of the mammalian proto-oncogene BCL6 , as a negative regulator of the JAK/STAT pathway. Ken genetically interacts with the pathway in vivo and recognizes a DNA consensus sequence overlapping that of STAT92E in vitro. Tissue culture-based assays demonstrate the existence of Ken-sensitive and Ken-insensitive STAT92E binding sites, while ectopically expressed Ken is sufficient to downregulate a subset of JAK/STAT pathway target genes in vivo. Finally, we show that endogenous Ken specifically represses JAK/STAT-dependent expression of ventral veins lacking (vvl) in the posterior spiracles. Ken therefore represents a novel regulator of JAK/STAT signaling whose dynamic spatial and temporal expression is capable of selectively modulating the transcriptional repertoire elicited by activated STAT92E in vivo. PMID:16401426

  7. Afzelin positively regulates melanogenesis through the p38 MAPK pathway.

    PubMed

    Jung, Eunsun; Kim, Jin Hee; Kim, Mi Ok; Jang, Sunghee; Kang, Mingyeong; Oh, Sae Woong; Nho, Youn Hwa; Kang, Seung Hyun; Kim, Min Hee; Park, See-Hyoung; Lee, Jongsung

    2016-07-25

    Melanogenesis refers to synthesis of the skin pigment melanin, which plays a critical role in the protection of skin against ultraviolet irradiation and oxidative stressors. We investigated the effects of afzelin on melanogenesis and its mechanisms of action in human epidermal melanocytes. In this study, we found that afzelin increased both melanin content and tyrosinase activity in a concentration-dependent manner. While the mRNA levels of microphthalmia-associated transcription factor (MITF), tyrosinase, and tyrosinase-related protein (TRP)-1 increased following afzelin treatment, the mRNA levels of TRP-2 were not affected by afzelin. Likewise, afzelin increased the protein levels of MITF, TRP-1, and tyrosinase but not TRP-2. Mechanistically, we found that afzelin regulated melanogenesis by upregulating MITF through phosphorylation of p38 mitogen-activated protein kinase (MAPK), independent of cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) signaling. Taken together, these findings indicate that the promotion of melanogenesis by afzelin occurs through increased MITF gene expression, which is mediated by activation of p38 MAPK, and suggest that afzelin may be useful as a protective agent against ultraviolet irradiation. PMID:27287415

  8. Aryl Hydrocarbon Receptor-Dependent Pathways in Immune Regulation.

    PubMed

    Gargaro, M; Pirro, M; Romani, R; Zelante, T; Fallarino, F

    2016-08-01

    The idea of possible involvement of the aryl hydrocarbon receptor (AhR) in transplant tolerance can be traced back >30 years, when very low doses of dioxin-the most potent AhR ligand-were found to markedly reduce the generation of cytotoxic T lymphocytes in response to alloantigen challenge in vivo. AhR is a ligand-activated transcription factor that is activated by dioxins and other environmental pollutants. We now know that AhR can bind a broad variety of activating ligands that are disparate in nature, including endogenous molecules and those formed in the gut from food and bacterial products. Consequently, in addition to its classical role as a toxicological signal mediator, AhR is emerging as a transcription factor involved in the regulation of both innate and adaptive immune responses in various immune cell types, including lymphocytes and antigen-presenting cells (APCs). Allograft rejection is mostly a T cell-mediated alloimmune response initiated by the recognition of alloantigens presented by donor and recipient APCs to recipient CD4(+) and CD8(+) T cells. Based on those findings, AhR may function as a critical sensor of outside and inside environments, leading to changes in the immune system that may have relevance in transplantation. PMID:26751261

  9. The Flavonoid Pathway Regulates the Petal Colors of Cotton Flower

    PubMed Central

    Tan, Jiafu; Wang, Maojun; Tu, Lili; Nie, Yichun; Lin, Yongjun; Zhang, Xianlong

    2013-01-01

    Although biochemists and geneticists have studied the cotton flower for more than one century, little is known about the molecular mechanisms underlying the dramatic color change that occurs during its short developmental life following blooming. Through the analysis of world cotton germplasms, we found that all of the flowers underwent color changes post-anthesis, but there is a diverse array of petal colors among cotton species, with cream, yellow and red colors dominating the color scheme. Genetic and biochemical analyses indicated that both the original cream and red colors and the color changes post-anthesis were related to flavonoid content. The anthocyanin content and the expression of biosynthesis genes were both increased from blooming to one day post-anthesis (DPA) when the flower was withering and undergoing abscission. Our results indicated that the color changes and flavonoid biosynthesis of cotton flowers were precisely controlled and genetically regulated. In addition, flavonol synthase (FLS) genes involved in flavonol biosynthesis showed specific expression at 11 am when the flowers were fully opened. The anthocyanidin reductase (ANR) genes, which are responsible for proanthocyanidins biosynthesis, showed the highest expression at 6 pm on 0 DPA, when the flowers were withered. Light showed primary, moderate and little effects on flavonol, anthocyanin and proanthocyanidin biosynthesis, respectively. Flavonol biosynthesis was in response to light exposure, while anthocyanin biosynthesis was involved in flower color changes. Further expression analysis of flavonoid genes in flowers of wild type and a flavanone 3-hydroxylase (F3H) silenced line showed that the development of cotton flower color was controlled by a complex interaction between genes and light. These results present novel information regarding flavonoids metabolism and flower development. PMID:23951318

  10. The Hippo Pathway Regulates Neuroblasts and Brain Size in Drosophila melanogaster.

    PubMed

    Poon, Carole L C; Mitchell, Katrina A; Kondo, Shu; Cheng, Louise Y; Harvey, Kieran F

    2016-04-25

    A key question in developmental neurobiology is how neural stem cells regulate their proliferative potential and cellular diversity and thus specify the overall size of the brain. Drosophila melanogaster neural stem cells (neuroblasts) are known to regulate their ability to self-renew by asymmetric cell division and produce different types of neurons and glia through sequential expression of temporal transcription factors [1]. Here, we show that the conserved Hippo pathway, a key regulator of epithelial organ size [2-4], restricts neuroblast proliferative potential and neuronal cell number to regulate brain size. The inhibition of Hippo pathway activity via depletion of the core kinases Tao-1, Hippo, or Warts regulates several key characteristics of neuroblasts during postembryonic neurogenesis. The Hippo pathway is required to maintain timely entry and exit from neurogenesis by regulating both neuroblast reactivation from quiescence and the time at which neuroblasts undergo terminal differentiation. Further, it restricts neuroblast cell-cycle speed, specifies cell size, and alters the proportion of neuron types generated during postembryonic neurogenesis. Collectively, deregulation of Hippo signaling in neuroblasts causes a substantial increase in overall brain size. We show that these effects are mediated via the key downstream transcription co-activator Yorkie and that, indeed, Yorkie overexpression in neuroblasts is sufficient to cause brain overgrowth. These studies reveal a novel mechanism that controls stem cell proliferative potential during postembryonic neurogenesis to regulate brain size. PMID:26996505

  11. The Protein Kinase A Pathway Regulates Zearalenone Production by Modulating Alternative ZEB2 Transcription.

    PubMed

    Park, Ae Ran; Fu, Minmin; Shin, Ji Young; Son, Hokyoung; Lee, Yin-Won

    2016-05-28

    Zearalenone (ZEA) is an estrogenic mycotoxin that is produced by several Fusarium species, including Fusarium graminearum. One of the ZEA biosynthetic genes, ZEB2, encodes two isoforms of Zeb2 by alternative transcription, forming an activator (Zeb2L-Zeb2L homooligomer) and an inhibitor (Zeb2L-Zeb2S heterodimer) that directly regulate the ZEA biosynthetic genes in F. graminearum. Cyclic AMP-dependent protein kinase A (PKA) signaling regulates secondary metabolic processes in several filamentous fungi. In this study, we investigated the effects of the PKA signaling pathway on ZEA biosynthesis. Through functional analyses of PKA catalytic and regulatory subunits (CPKs and PKR), we found that the PKA pathway negatively regulates ZEA production. Genetic and biochemical evidence further demonstrated that the PKA pathway specifically represses ZEB2L transcription and also takes part in posttranscriptional regulation of ZEB2L during ZEA production. Our findings reveal the intriguing mechanism that the PKA pathway regulates secondary metabolite production by reprograming alternative transcription. PMID:26907763

  12. Two Drosophila suppressors of cytokine signaling (SOCS) differentially regulate JAK and EGFR pathway activities

    PubMed Central

    Rawlings, Jason S; Rennebeck, Gabriela; Harrison, Susan MW; Xi, Rongwen; Harrison, Douglas A

    2004-01-01

    Background The Janus kinase (JAK) cascade is an essential and well-conserved pathway required to transduce signals for a variety of ligands in both vertebrates and invertebrates. While activation of the pathway is essential to many processes, mutations from mammals and Drosophila demonstrate that regulation is also critical. The SOCS (Suppressor Of Cytokine Signaling) proteins in mammals are regulators of the JAK pathway that participate in a negative feedback loop, as they are transcriptionally activated by JAK signaling. Examination of one Drosophila SOCS homologue, Socs36E, demonstrated that its expression is responsive to JAK pathway activity and it is capable of downregulating JAK signaling, similar to the well characterized mammalian SOCS. Results Based on sequence analysis of the Drosophila genome, there are three identifiable SOCS homologues in flies. All three are most similar to mammalian SOCS that have not been extensively characterized: Socs36E is most similar to mammalian SOCS5, while Socs44A and Socs16D are most similar to mammalian SOCS6 and 7. Although Socs44A is capable of repressing JAK activity in some tissues, its expression is not regulated by the pathway. Furthermore, Socs44A can enhance the activity of the EGFR/MAPK signaling cascade, in contrast to Socs36E. Conclusions Two Drosophila SOCS proteins have some overlapping and some distinct capabilities. While Socs36E behaves similarly to the canonical vertebrate SOCS, Socs44A is not part of a JAK pathway negative feedback loop. Nonetheless, both SOCS regulate JAK and EGFR signaling pathways, albeit differently. The non-canonical properties of Socs44A may be representative of the class of less characterized vertebrate SOCS with which it shares greatest similarity. PMID:15488148

  13. Snail Coordinately Regulates Downstream Pathways to Control Multiple Aspects of Mammalian Neural Precursor Development

    PubMed Central

    Zander, Mark A.; Burns, Sarah E.; Yang, Guang; Kaplan, David R.

    2014-01-01

    The Snail transcription factor plays a key role in regulating diverse developmental processes but is not thought to play a role in mammalian neural precursors. Here, we have examined radial glial precursor cells of the embryonic murine cortex and demonstrate that Snail regulates their survival, self-renewal, and differentiation into intermediate progenitors and neurons via two distinct and separable target pathways. First, Snail promotes cell survival by antagonizing a p53-dependent death pathway because coincident p53 knockdown rescues survival deficits caused by Snail knockdown. Second, we show that the cell cycle phosphatase Cdc25b is regulated by Snail in radial precursors and that Cdc25b coexpression is sufficient to rescue the decreased radial precursor proliferation and differentiation observed upon Snail knockdown. Thus, Snail acts via p53 and Cdc25b to coordinately regulate multiple aspects of mammalian embryonic neural precursor biology. PMID:24719096

  14. The octadecanoic pathway: signal molecules for the regulation of secondary pathways.

    PubMed Central

    Blechert, S; Brodschelm, W; Hölder, S; Kammerer, L; Kutchan, T M; Mueller, M J; Xia, Z Q; Zenk, M H

    1995-01-01

    Plant defense against microbial pathogens and herbivores relies heavily on the induction of defense proteins and low molecular weight antibiotics. The signals between perception of the aggression, gene activation, and the subsequent biosynthesis of secondary compounds are assumed to be pentacylic oxylipin derivatives. The rapid, but transient, synthesis of cis-jasmonic acid was demonstrated after insect attack on a food plant and by microbial elicitor addition to plant suspension cultures. This effect is highly specific and not caused by a number of environmental stresses such as light, heavy metals, or cold or heat shock. Elicitation of Eschscholtzia cell cultures also led to a rapid alkalinization of the growth medium prior to jasmonate formation. Inhibition of this alkalinization process by the protein kinase inhibitor staurosporine also inhibited jasmonate formation. The induction of specific enzymes in the benzo[c]phenanthridine alkaloid pathway leading to the antimicrobial sanguinarine was induced to a qualitatively and quantitatively similar extent by fungal elicitor, methyl jasmonate, and its linolenic acid-derived precursor 12-oxophytodienoic acid. It is herein proposed that a second oxylipid cascade may exist in plants starting from linoleic acid via 15,16-dihydro-12-oxophytodienoic acid to 9,10-dihydrojasmonate. Experiments with synthetic trihomojasmonate demonstrated that beta-oxidation is not a prerequisite for biological activity and that 12-oxophytodienoic acid and derivatives are most likely fully active as signal transducers. Octadecanoic acid-derived compounds are essential elements in modulating the synthesis of antibiotic compounds and are thus integral to plant defense. Images Fig. 4 Fig. 9 PMID:7753776

  15. A constitutive active MAPK/ERK pathway due to BRAFV600E positively regulates AHR pathway in PTC.

    PubMed

    Occhi, Gianluca; Barollo, Susi; Regazzo, Daniela; Bertazza, Loris; Galuppini, Francesca; Guzzardo, Vincenza; Jaffrain-Rea, Marie Lise; Vianello, Federica; Ciato, Denis; Ceccato, Filippo; Watutantrige-Fernando, Sara; Bisognin, Andrea; Bortoluzzi, Stefania; Pennelli, Gianmaria; Boscaro, Marco; Scaroni, Carla; Mian, Caterina

    2015-10-13

    The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor mediating the toxicity and tumor-promoting properties of dioxin. AHR has been reported to be overexpressed and constitutively active in a variety of solid tumors, but few data are currently available concerning its role in thyroid cancer. In this study we quantitatively explored a series of 51 paired-normal and papillary thyroid carcinoma (PTC) tissues for AHR-related genes. We identified an increased AHR expression/activity in PTC, independently from its nuclear dimerization partner and repressor but strictly related to a constitutive active MAPK/ERK pathway. The AHR up-regulation followed by an increased expression of AHR target genes was confirmed by a meta-analysis of published microarray data, suggesting a ligand-independent active AHR pathway in PTC. In-vitro studies using a PTC-derived cell line (BCPAP) and HEK293 cells showed that BRAFV600E may directly modulate AHR localization, induce AHR expression and activity in an exogenous ligand-independent manner. The AHR pathway might represent a potential novel therapeutic target for PTC in the clinical practice. PMID:26392334

  16. Molecular chaperone Hsp27 regulates the Hippo tumor suppressor pathway in cancer.

    PubMed

    Vahid, Sepideh; Thaper, Daksh; Gibson, Kate F; Bishop, Jennifer L; Zoubeidi, Amina

    2016-01-01

    Heat shock protein 27 (Hsp27) is a molecular chaperone highly expressed in aggressive cancers, where it is involved in numerous pro-tumorigenic signaling pathways. Using functional genomics we identified for the first time that Hsp27 regulates the gene signature of transcriptional co-activators YAP and TAZ, which are negatively regulated by the Hippo Tumor Suppressor pathway. The Hippo pathway inactivates YAP by phosphorylating and increasing its cytoplasmic retention with the 14.3.3 proteins. Gain and loss of function experiments in prostate, breast and lung cancer cells showed that Hsp27 knockdown induced YAP phosphorylation and cytoplasmic localization while overexpression of Hsp27 displayed opposite results. Mechanistically, Hsp27 regulates the Hippo pathway by accelerating the proteasomal degradation of ubiquitinated MST1, the core Hippo kinase, resulting in reduced phosphorylation/activity of LATS1 and MOB1, its downstream effectors. Importantly, our in vitro results were supported by data from human tumors; clinically, high expression of Hsp27 in prostate tumors is correlated with increased expression of YAP gene signature and reduced phosphorylation of YAP in lung and invasive breast cancer clinical samples. This study reveals for the first time a link between Hsp27 and the Hippo cascade, providing a novel mechanism of deregulation of this tumor suppressor pathway across multiple cancers. PMID:27555231

  17. Molecular chaperone Hsp27 regulates the Hippo tumor suppressor pathway in cancer

    PubMed Central

    Vahid, Sepideh; Thaper, Daksh; Gibson, Kate F.; Bishop, Jennifer L.; Zoubeidi, Amina

    2016-01-01

    Heat shock protein 27 (Hsp27) is a molecular chaperone highly expressed in aggressive cancers, where it is involved in numerous pro-tumorigenic signaling pathways. Using functional genomics we identified for the first time that Hsp27 regulates the gene signature of transcriptional co-activators YAP and TAZ, which are negatively regulated by the Hippo Tumor Suppressor pathway. The Hippo pathway inactivates YAP by phosphorylating and increasing its cytoplasmic retention with the 14.3.3 proteins. Gain and loss of function experiments in prostate, breast and lung cancer cells showed that Hsp27 knockdown induced YAP phosphorylation and cytoplasmic localization while overexpression of Hsp27 displayed opposite results. Mechanistically, Hsp27 regulates the Hippo pathway by accelerating the proteasomal degradation of ubiquitinated MST1, the core Hippo kinase, resulting in reduced phosphorylation/activity of LATS1 and MOB1, its downstream effectors. Importantly, our in vitro results were supported by data from human tumors; clinically, high expression of Hsp27 in prostate tumors is correlated with increased expression of YAP gene signature and reduced phosphorylation of YAP in lung and invasive breast cancer clinical samples. This study reveals for the first time a link between Hsp27 and the Hippo cascade, providing a novel mechanism of deregulation of this tumor suppressor pathway across multiple cancers. PMID:27555231

  18. Two novel regulators of N-acetyl-galactosamine utilization pathway and distinct roles in bacterial infections.

    PubMed

    Zhang, Huimin; Ravcheev, Dmitry A; Hu, Dan; Zhang, Fengyu; Gong, Xiufang; Hao, Lina; Cao, Min; Rodionov, Dmitry A; Wang, Changjun; Feng, Youjun

    2015-12-01

    Bacterial pathogens can exploit metabolic pathways to facilitate their successful infection cycles, but little is known about roles of d-galactosamine (GalN)/N-acetyl-d-galactosamine (GalNAc) catabolism pathway in bacterial pathogenesis. Here, we report the genomic reconstruction of GalN/GalNAc utilization pathway in Streptococci and the diversified aga regulons. We delineated two new paralogous AgaR regulators for the GalN/GalNAc catabolism pathway. The electrophoretic mobility shift assays experiment demonstrated that AgaR2 (AgaR1) binds the predicted palindromes, and the combined in vivo data from reverse transcription quantitative polymerase chain reaction and RNA-seq suggested that AgaR2 (not AgaR1) can effectively repress the transcription of the target genes. Removal of agaR2 (not agaR1) from Streptococcus suis 05ZYH33 augments significantly the abilities of both adherence to Hep-2 cells and anti-phagocytosis against RAW264.7 macrophage. As anticipated, the dysfunction in AgaR2-mediated regulation of S. suis impairs its pathogenicity in experimental models of both mice and piglets. Our finding discovered two novel regulators specific for GalN/GalNAc catabolism and assigned them distinct roles into bacterial infections. To the best of our knowledge, it might represent a first paradigm that links the GalN/GalNAc catabolism pathway to bacterial pathogenesis. PMID:26540018

  19. Bioinformatic Evaluation of Transcriptional Regulation of WNT Pathway Genes with reference to Diabetic Nephropathy

    PubMed Central

    McKay, Gareth J.; Kavanagh, David H.; Crean, John K.; Maxwell, Alexander P.

    2016-01-01

    Objective. WNT/β-catenin pathway members have been implicated in interstitial fibrosis and glomerular sclerosis disease processes characteristic of diabetic nephropathy (DN), processes partly controlled by transcription factors (TFs) that bind to gene promoter regions attenuating regulation. We sought to identify predicted cis-acting transcription factor binding sites (TFBSs) overrepresented within WNT pathway members. Methods. We assessed 62 TFBS motif frequencies from the JASPAR databases in 65 WNT pathway genes. P values were estimated on the hypergeometric distribution for each TF. Gene expression profiles of enriched motifs were examined in DN-related datasets to assess clinical significance. Results. Transcription factor AP-2 alpha (TFAP2A), myeloid zinc finger 1 (MZF1), and specificity protein 1 (SP1) were significantly enriched within WNT pathway genes (P values < 6.83 × 10−29, 1.34 × 10−11, and 3.01 × 10−6, resp.). MZF1 expression was significantly increased in DN in a whole kidney dataset (fold change = 1.16; 16% increase; P = 0.03). TFAP2A expression was decreased in an independent dataset (fold change = −1.02; P = 0.03). No differential expression of SP1 was detected. Conclusions. Three TFBS profiles are significantly enriched within WNT pathway genes highlighting the potential of in silico analyses for identification of pathway regulators. Modification of TF binding may possibly limit DN progression, offering potential therapeutic benefit. PMID:26697505

  20. Putting the pieces together: How is the mitochondrial pathway of apoptosis regulated in cancer and chemotherapy?

    PubMed Central

    2014-01-01

    In order to solve a jigsaw puzzle, one must first have the complete picture to logically connect the pieces. However, in cancer biology, we are still gaining an understanding of all the signaling pathways that promote tumorigenesis and how these pathways can be pharmacologically manipulated by conventional and targeted therapies. Despite not having complete knowledge of the mechanisms that cause cancer, the signaling networks responsible for cancer are becoming clearer, and this information is serving as a solid foundation for the development of rationally designed therapies. One goal of chemotherapy is to induce cancer cell death through the mitochondrial pathway of apoptosis. Within this review, we present the pathways that govern the cellular decision to undergo apoptosis as three distinct, yet connected puzzle pieces: (1) How do oncogene and tumor suppressor pathways regulate apoptosis upstream of mitochondria? (2) How does the B-cell lymphoma 2 (BCL-2) family influence tumorigenesis and chemotherapeutic responses? (3) How is post-mitochondrial outer membrane permeabilization (MOMP) regulation of cell death relevant in cancer? When these pieces are united, it is possible to appreciate how cancer signaling directly impacts upon the fundamental cellular mechanisms of apoptosis and potentially reveals novel pharmacological targets within these pathways that may enhance chemotherapeutic success. PMID:25621172

  1. Cell polarity pathways converge and extend to regulate neural tube closure.

    PubMed

    Zohn, Irene E; Chesnutt, Catherine R; Niswander, Lee

    2003-09-01

    Neural tube defects, such as spinabifida, craniorachischisis and anencephaly, are some of the most common birth defects in humans. Recent studies in mouse model systems suggest that craniorachischisis is associated with mutations in genes that regulate cell polarity. Using Xenopus as a model system, Wallingford and Harland have now shed light on the mechanism by which these pathways affect neural tube closure. PMID:12946622

  2. miRNA Profiling Reveals Dysregulation of RET and RET-Regulating Pathways in Hirschsprung's Disease.

    PubMed

    Li, Shuangshuang; Wang, Shiqi; Guo, Zhenhua; Wu, Huan; Jin, Xianqing; Wang, Yi; Li, Xiaoqing; Liang, Shaoyan

    2016-01-01

    Hirschsprung's disease (HSCR), the most common congenital malformation of the gut, is regulated by multiple signal transduction pathways. Several components of these pathways are important targets for microRNAs (miRNAs). Multiple miRNAs have been associated with the pathophysiology of HSCR, and serum miRNAs profiles of HSCR patients have been reported, but miRNA expression in HSCR colon tissue is almost completely unexplored. Using microarray technology, we screened colon tissue to detect miRNAs whose expression profiles were altered in HSCR and identify targets of differentially expressed miRNAs. Following filtering of low-intensity signals, data normalization, and volcano plot filtering, we identified 168 differentially expressed miRNAs (104 up-regulated and 64 down-regulated). Fifty of these mRNAs represent major targets of dysegulated miRNAs and may thus important roles in the pathophysiology of HSCR. Pathway analysis revealed that 7 of the miRNA targets encode proteins involved in regulation of cell proliferation and migration via RET and related signaling pathways (MAPK and PI3K/AKT). Our results identify miRNAs that play key roles in the pathophysiology of the complex multi-factorial disease HSCR. PMID:26933947

  3. miRNA Profiling Reveals Dysregulation of RET and RET-Regulating Pathways in Hirschsprung's Disease

    PubMed Central

    Li, Shuangshuang; Wang, Shiqi; Guo, Zhenhua; Wu, Huan; Jin, Xianqing; Wang, Yi; Li, Xiaoqing; Liang, Shaoyan

    2016-01-01

    Hirschsprung’s disease (HSCR), the most common congenital malformation of the gut, is regulated by multiple signal transduction pathways. Several components of these pathways are important targets for microRNAs (miRNAs). Multiple miRNAs have been associated with the pathophysiology of HSCR, and serum miRNAs profiles of HSCR patients have been reported, but miRNA expression in HSCR colon tissue is almost completely unexplored. Using microarray technology, we screened colon tissue to detect miRNAs whose expression profiles were altered in HSCR and identify targets of differentially expressed miRNAs. Following filtering of low-intensity signals, data normalization, and volcano plot filtering, we identified 168 differentially expressed miRNAs (104 up-regulated and 64 down-regulated). Fifty of these mRNAs represent major targets of dysegulated miRNAs and may thus important roles in the pathophysiology of HSCR. Pathway analysis revealed that 7 of the miRNA targets encode proteins involved in regulation of cell proliferation and migration via RET and related signaling pathways (MAPK and PI3K/AKT). Our results identify miRNAs that play key roles in the pathophysiology of the complex multi-factorial disease HSCR. PMID:26933947

  4. Controlled sumoylation of the mevalonate pathway enzyme HMGS-1 regulates metabolism during aging

    PubMed Central

    Sapir, Amir; Tsur, Assaf; Koorman, Thijs; Ching, Kaitlin; Mishra, Prashant; Bardenheier, Annabelle; Podolsky, Lisa; Bening-Abu-Shach, Ulrike; Boxem, Mike; Chou, Tsui-Fen; Broday, Limor; Sternberg, Paul W.

    2014-01-01

    Many metabolic pathways are critically regulated during development and aging but little is known about the molecular mechanisms underlying this regulation. One key metabolic cascade in eukaryotes is the mevalonate pathway. It catalyzes the synthesis of sterol and nonsterol isoprenoids, such as cholesterol and ubiquinone, as well as other metabolites. In humans, an age-dependent decrease in ubiquinone levels and changes in cholesterol homeostasis suggest that mevalonate pathway activity changes with age. However, our knowledge of the mechanistic basis of these changes remains rudimentary. We have identified a regulatory circuit controlling the sumoylation state of Caenorhabditis elegans HMG-CoA synthase (HMGS-1). This protein is the ortholog of human HMGCS1 enzyme, which mediates the first committed step of the mevalonate pathway. In vivo, HMGS-1 undergoes an age-dependent sumoylation that is balanced by the activity of ULP-4 small ubiquitin-like modifier protease. ULP-4 exhibits an age-regulated expression pattern and a dynamic cytoplasm-to-mitochondria translocation. Thus, spatiotemporal ULP-4 activity controls the HMGS-1 sumoylation state in a mechanism that orchestrates mevalonate pathway activity with the age of the organism. To expand the HMGS-1 regulatory network, we combined proteomic analyses with knockout studies and found that the HMGS-1 level is also governed by the ubiquitin–proteasome pathway. We propose that these conserved molecular circuits have evolved to govern the level of mevalonate pathway flux during aging, a flux whose dysregulation is associated with numerous age-dependent cardiovascular and cancer pathologies. PMID:25187565

  5. Curcumin and Emodin Down-Regulate TGF-β Signaling Pathway in Human Cervical Cancer Cells

    PubMed Central

    Thacker, Pooja Chandrakant; Karunagaran, Devarajan

    2015-01-01

    Cervical cancer is the major cause of cancer related deaths in women, especially in developing countries and Human Papilloma Virus infection in conjunction with multiple deregulated signaling pathways leads to cervical carcinogenesis. TGF-β signaling in later stages of cancer is known to induce epithelial to mesenchymal transition promoting tumor growth. Phytochemicals, curcumin and emodin, are effective as chemopreventive and chemotherapeutic compounds against several cancers including cervical cancer. The main objective of this work was to study the effect of curcumin and emodin on TGF-β signaling pathway and its functional relevance to growth, migration and invasion in two cervical cancer cell lines, SiHa and HeLa. Since TGF-β and Wnt/β-catenin signaling pathways are known to cross talk having common downstream targets, we analyzed the effect of TGF-β on β-catenin (an important player in Wnt/β-catenin signaling) and also studied whether curcumin and emodin modulate them. We observed that curcumin and emodin effectively down regulate TGF-β signaling pathway by decreasing the expression of TGF-β Receptor II, P-Smad3 and Smad4, and also counterbalance the tumorigenic effects of TGF-β by inhibiting the TGF-β-induced migration and invasion. Expression of downstream effectors of TGF-β signaling pathway, cyclinD1, p21 and Pin1, was inhibited along with the down regulation of key mesenchymal markers (Snail and Slug) upon curcumin and emodin treatment. Curcumin and emodin were also found to synergistically inhibit cell population and migration in SiHa and HeLa cells. Moreover, we found that TGF-β activates Wnt/β-catenin signaling pathway in HeLa cells, and curcumin and emodin down regulate the pathway by inhibiting β-catenin. Taken together our data provide a mechanistic basis for the use of curcumin and emodin in the treatment of cervical cancer. PMID:25786122

  6. MicroRNAs Regulating Signaling Pathways: Potential Biomarkers in Systemic Sclerosis

    PubMed Central

    Li, Yisha; Huang, Jing; Guo, Muyao; Zuo, Xiaoxia

    2015-01-01

    Systemic sclerosis (SSc) is a multisystem fibrotic and autoimmune disease. Both genetic and epigenetic elements mediate SSc pathophysiology. This review summarizes the role of one epigenetic element, known as microRNAs (miRNAs), involved in different signaling pathways of SSc pathogenesis. The expression of key components in transforming growth factor-β (TGF-β) signaling pathway has been found to be regulated by miRNAs both upstream and downstream of TGF-β. We are specifically interested in the pathway components upstream of TGF-β, while miRNAs in other signaling pathways have not been extensively studied. The emerging role of miRNAs in vasculopathy of SSc suggests a promising new direction for future investigation. Elucidation of the regulatory role of miRNAs in the expression of signaling factors may facilitate the discovery of novel biomarkers in SSc and improve the understanding and treatment of this disease. PMID:26365208

  7. Hippo signaling regulates Drosophila intestine stem cell proliferation through multiple pathways

    PubMed Central

    Ren, Fangfang; Wang, Bing; Yue, Tao; Yun, Eun-Young; Ip, Y. Tony; Jiang, Jin

    2010-01-01

    Intestinal stem cells (ISCs) in the Drosophila adult midgut are essential for maintaining tissue homeostasis and replenishing lost cells in response to tissue damage. Here we demonstrate that the Hippo (Hpo) signaling pathway, an evolutionarily conserved pathway implicated in organ size control and tumorigenesis, plays an essential role in regulating ISC proliferation. Loss of Hpo signaling in either midgut precursor cells or epithelial cells stimulates ISC proliferation. We provide evidence that loss of Hpo signaling in epithelial cells increases the production of cytokines of the Upd family and multiple EGFR ligands that activate JAK-STAT and EGFR signaling pathways in ISCs to stimulate their proliferation, thus revealing a unique non–cell-autonomous role of Hpo signaling in blocking ISC proliferation. Finally, we show that the Hpo pathway mediator Yorkie (Yki) is also required in precursor cells for injury-induced ISC proliferation in response to tissue-damaging reagent DSS. PMID:21078993

  8. Regulation of TRPM7 Function by IL-6 through the JAK2-STAT3 Signaling Pathway

    PubMed Central

    Wang, Jing; Zhao, Yin; Luo, Zhenzhao; Gao, Yan; Shi, Jing

    2016-01-01

    Aims Previous studies have demonstrated that expression of the TRPM7 channel, which may induce delayed cell death by mediating calcium influx, is precisely regulated. However, functional regulation of TRPM7 channels by endogenous molecules has not been elucidated. The proinflammatory cytokine IL-6 contributes to regulation of Ca2+ influx in cerebral ischemia, but the role of IL-6 in regulating TRPM7 functioning is unknown. Thus, we here investigated the interaction between IL-6 and TRPM7 channels and the relevant mechanisms. Materials and Methods Using whole-cell patch-clamping, we first investigated the effect of IL-6 on TRPM7-like currents in primary cultured cortical neurons. Next, TRPM7-overexpressing HEK293 cells were used to confirm the effect of IL-6/sIL-6R on TRPM7. Finally, we used specific signaling pathway inhibitors to investigate the signaling pathways involved. Results IL-6 or IL-6/sIL-6R dose-dependently inhibited inward TRPM7 currents, in both primary cultured neurons and HEK293 cells overexpressing TRPM7. In intracellular Mg2+-free conditions, extracellular Ca2+ or the α-kinase domain of TRPM7 did not participate in this regulation. The inhibitory effect of IL-6 on TRPM7 could be blocked by specific inhibitors of the JAK2−STAT3 pathway, but not of the PI3K, ERK1/2, or PLC pathways. Conclusions IL-6 inhibits the inward TRPM7 current via the JAK2−STAT3 signaling pathway. PMID:27010689

  9. PDK1-Akt pathway regulates radial neuronal migration and microtubules in the developing mouse neocortex.

    PubMed

    Itoh, Yasuhiro; Higuchi, Maiko; Oishi, Koji; Kishi, Yusuke; Okazaki, Tomohiko; Sakai, Hiroshi; Miyata, Takaki; Nakajima, Kazunori; Gotoh, Yukiko

    2016-05-24

    Neurons migrate a long radial distance by a process known as locomotion in the developing mammalian neocortex. During locomotion, immature neurons undergo saltatory movement along radial glia fibers. The molecular mechanisms that regulate the speed of locomotion are largely unknown. We now show that the serine/threonine kinase Akt and its activator phosphoinositide-dependent protein kinase 1 (PDK1) regulate the speed of locomotion of mouse neocortical neurons through the cortical plate. Inactivation of the PDK1-Akt pathway impaired the coordinated movement of the nucleus and centrosome, a microtubule-dependent process, during neuronal migration. Moreover, the PDK1-Akt pathway was found to control microtubules, likely by regulating the binding of accessory proteins including the dynactin subunit p150(glued) Consistent with this notion, we found that PDK1 regulates the expression of cytoplasmic dynein intermediate chain and light intermediate chain at a posttranscriptional level in the developing neocortex. Our results thus reveal an essential role for the PDK1-Akt pathway in the regulation of a key step of neuronal migration. PMID:27170189

  10. Secretory protein traffic. Chromogranin A contains a dominant targeting signal for the regulated pathway.

    PubMed Central

    Parmer, R J; Xi, X P; Wu, H J; Helman, L J; Petz, L N

    1993-01-01

    Secretory proteins are targeted into either constitutive (secreted upon synthesis) or regulated (stored in vesicles and released in response to a secretagogue) pathways. To investigate mechanisms of protein targeting into catecholamine storage vesicles (CSV), we stably expressed human chromogranin A (CgA), the major soluble protein in human CSV, in the rat pheochromocytoma PC-12 cell line. Chromaffin cell secretagogues (0.1 mM nicotinic cholinergic agonist, 55 mM K+, or 2 mM Ba++) caused cosecretion of human CgA and catecholamines from human CgA-expressing cells. Sucrose gradients colocalized human CgA and catecholamines to subcellular particles of the same buoyant density. Chimeric proteins, in which human CgA (either full-length [457 amino acids] or truncated [amino-terminal 226 amino acids]) was fused in-frame to the ordinarily nonsecreted protein chloramphenicol acetyltransferase (CAT), were expressed transiently in PC-12 cells. Both constructs directed CAT activity into regulated secretory vesicles, as judged by secretagogue-stimulated release. These data demonstrate that human CgA expressed in PC-12 cells is targeted to regulated secretory vesicles. In addition, human CgA can divert an ordinarily non-secreted protein into the regulated secretory pathway, consistent with the operation of a dominant targeting signal for the regulated pathway within the peptide sequence of CgA. Images PMID:8394383

  11. The STARS signaling pathway: a key regulator of skeletal muscle function.

    PubMed

    Lamon, Séverine; Wallace, Marita A; Russell, Aaron P

    2014-09-01

    During the last decade, the striated muscle activator of Rho signaling (STARS), a muscle-specific protein, has been proposed to play an increasingly important role in skeletal muscle growth, metabolism, regeneration and stress adaptation. STARS influences actin dynamics and, as a consequence, regulates the myocardin-related transcription factor A/serum response factor (MRTF-A/SRF) transcriptional program, a well-known pathway controlling skeletal muscle development and function. Muscle-specific stress conditions, such as exercise, positively regulates, while disuse and degenerative muscle diseases are associated with a downregulation of STARS and its downstream partners, suggesting a pivotal role for STARS in skeletal muscle health. This review provides a comprehensive overview of the known role and regulation of STARS and the members of its signaling pathway, RhoA, MRTF-A and SRF, in skeletal muscle. PMID:24557714

  12. Emerging Roles for Intersectin (ITSN) in Regulating Signaling and Disease Pathways

    PubMed Central

    Hunter, Michael P.; Russo, Angela; O’Bryan, John P.

    2013-01-01

    Intersectins (ITSNs) represent a family of multi-domain adaptor proteins that regulate endocytosis and cell signaling. ITSN genes are highly conserved and present in all metazoan genomes examined thus far. Lower eukaryotes have only one ITSN gene, whereas higher eukaryotes have two ITSN genes. ITSN was first identified as an endocytic scaffold protein, and numerous studies reveal a conserved role for ITSN in endocytosis. Subsequently, ITSNs were found to regulate multiple signaling pathways including receptor tyrosine kinases (RTKs), GTPases, and phosphatidylinositol 3-kinase Class 2beta (PI3KC2β). ITSN has also been implicated in diseases such as Down Syndrome (DS), Alzheimer Disease (AD), and other neurodegenerative disorders. This review summarizes the evolutionary conservation of ITSN, the latest research on the role of ITSN in endocytosis, the emerging roles of ITSN in regulating cell signaling pathways, and the involvement of ITSN in human diseases such as DS, AD, and cancer. PMID:23574942

  13. Activation of the TOR Signalling Pathway by Glutamine Regulates Insect Fecundity

    PubMed Central

    Zhai, Yifan; Sun, Zhongxiang; Zhang, Jianqing; Kang, Kui; Chen, Jie; Zhang, Wenqing

    2015-01-01

    The target of rapamycin (TOR) positively controls cell growth in response to nutrients such as amino acids. However, research on the specific nutrients sensed by TOR is limited. Glutamine (Gln), a particularly important amino acid involved in metabolism in organisms, is synthesised and catalysed exclusively by glutamine synthetase (GS), and our previous studies have shown that Gln may regulate fecundity in vivo levels of the brown planthopper (BPH) Nilaparvata lugens. Until now, it has remained unclear whether Gln activates or inhibits the TOR signalling pathway. Here, we performed the combined analyses of iTRAQ (isobaric tags for relative and absolute quantification) and DGE (tag-based digital gene expression) data in N.lugens at the protein and transcript levels after GS RNAi, and we found that 52 pathways overlap, including the TOR pathway. We further experimentally demonstrate that Gln activates the TOR pathway by promoting the serine/threonine protein kinase AKT and inhibiting the 5′AMP-activated protein kinase AMPK phosphorylation activity in the pest. Furthermore, TOR regulates the fecundity of N. lugens probably by mediating vitellogenin (Vg) expression. This work is the first report that Gln activates the TOR pathway in vivo. PMID:26024507

  14. Activation of the TOR Signalling Pathway by Glutamine Regulates Insect Fecundity.

    PubMed

    Zhai, Yifan; Sun, Zhongxiang; Zhang, Jianqing; Kang, Kui; Chen, Jie; Zhang, Wenqing

    2015-01-01

    The target of rapamycin (TOR) positively controls cell growth in response to nutrients such as amino acids. However, research on the specific nutrients sensed by TOR is limited. Glutamine (Gln), a particularly important amino acid involved in metabolism in organisms, is synthesised and catalysed exclusively by glutamine synthetase (GS), and our previous studies have shown that Gln may regulate fecundity in vivo levels of the brown planthopper (BPH) Nilaparvata lugens. Until now, it has remained unclear whether Gln activates or inhibits the TOR signalling pathway. Here, we performed the combined analyses of iTRAQ (isobaric tags for relative and absolute quantification) and DGE (tag-based digital gene expression) data in N. lugens at the protein and transcript levels after GS RNAi, and we found that 52 pathways overlap, including the TOR pathway. We further experimentally demonstrate that Gln activates the TOR pathway by promoting the serine/threonine protein kinase AKT and inhibiting the 5'AMP-activated protein kinase AMPK phosphorylation activity in the pest. Furthermore, TOR regulates the fecundity of N. lugens probably by mediating vitellogenin (Vg) expression. This work is the first report that Gln activates the TOR pathway in vivo. PMID:26024507

  15. Serpin-5 regulates prophenoloxidase activation and antimicrobial peptide pathways in the silkworm, Bombyx mori.

    PubMed

    Li, Junlan; Ma, Li; Lin, Zhe; Zou, Zhen; Lu, Zhiqiang

    2016-06-01

    The prophenoloxidase (PPO) activation pathway and Toll pathway are two critical insect immune responses against microbial infection. Activation of these pathways is mediated by an extracellular serine protease cascade, which is negatively regulated by serpins. In this study, we found that the mRNA abundance of silkworm serpin-5 (BmSpn-5) increased dramatically in the fat body after bacterial infection. The expression level of antimicrobial peptides (AMPs), gloverin-3, cecropin-D and -E decreased in the silkworm larvae injected with recombinant BmSpn-5 protein. Meanwhile, the inhibition of beads melanization, systemic melanization and PPO activation by BmSpn-5 was also observed. By means of immunoaffinity purification and analysis by mass spectrometry, we identified that the silkworm clip domain serine proteases BmHP6 and BmSP21 form a complex with BmSpn-5, which suggests that BmHP6 and SP21 are the cognate proteases of BmSpn-5 and are essential in the serine protease cascade that activates the Toll and PPO pathways. Our study provides a comprehensive characterization of BmSpn-5 and sheds light on the multiple pathways leading to PPO activation and their regulation by serpins. PMID:27084699

  16. Pathways to Sexual Offense Recidivism Following Treatment: An Examination of the Ward and Hudson Self-Regulation Model of Relapse

    ERIC Educational Resources Information Center

    Webster, Stephen D.

    2005-01-01

    Ward and Hudson (1998, 2000) proposed a self-regulation model of relapse in sexual offenders, which classifies offenders into one of four pathways. This study examined the validity of the model, whether sexual recidivists are characterized by one predominant pathway and offense type, and whether participants would change pathway pre- to…

  17. Coordinate regulation of the tryptophan biosynthetic pathway and indolic phytoalexin accumulation in Arabidopsis.

    PubMed Central

    Zhao, J; Last, R L

    1996-01-01

    Little is known about the mechanisms that couple regulation of secondary metabolic pathways to the synthesis of primary metabolic precursors. Camalexin, an indolic secondary metabolite, appears to be the major phytoalexin in Arabidopsis. It was previously shown that camalexin accumulation is caused by infection with plant pathogens, by abiotic elicitors, and in spontaneous lesions in the accelerated cell death mutant acd2. We demonstrate that the accumulation of this phytoalexin is accompanied by the induction of the mRNAs and proteins for all of the tryptophan biosynthetic enzymes tested. A strong correlation was observed between the magnitude of camalexin accumulation and the induction of tryptophan biosynthetic proteins, indicating coordinate regulation of these processes. Production of disease symptoms is not sufficient for the response because systemic infection with cauliflower mosaic virus or cucumber mosaic virus did not induce the tryptophan pathway enzymes or camalexin accumulation. Salicylic acid appears to be required, but unlike other documented pathogenesis-related proteins, it is not sufficient for the coordinate induction. Results with trp mutants suggest that the tryptophan pathway is not rate limiting for camalexin accumulation. Taken together, these results are consistent with the hypothesis that the regulation of the tryptophan pathway in plants responds to needs for biosynthesis of secondary metabolites. PMID:8989880

  18. Integrated genomic approaches identify major pathways and upstream regulators in late onset Alzheimer’s disease

    PubMed Central

    Li, Xinzhong; Long, Jintao; He, Taigang; Belshaw, Robert; Scott, James

    2015-01-01

    Previous studies have evaluated gene expression in Alzheimer’s disease (AD) brains to identify mechanistic processes, but have been limited by the size of the datasets studied. Here we have implemented a novel meta-analysis approach to identify differentially expressed genes (DEGs) in published datasets comprising 450 late onset AD (LOAD) brains and 212 controls. We found 3124 DEGs, many of which were highly correlated with Braak stage and cerebral atrophy. Pathway Analysis revealed the most perturbed pathways to be (a) nitric oxide and reactive oxygen species in macrophages (NOROS), (b) NFkB and (c) mitochondrial dysfunction. NOROS was also up-regulated, and mitochondrial dysfunction down-regulated, in healthy ageing subjects. Upstream regulator analysis predicted the TLR4 ligands, STAT3 and NFKBIA, for activated pathways and RICTOR for mitochondrial genes. Protein-protein interaction network analysis emphasised the role of NFKB; identified a key interaction of CLU with complement; and linked TYROBP, TREM2 and DOK3 to modulation of LPS signalling through TLR4 and to phosphatidylinositol metabolism. We suggest that NEUROD6, ZCCHC17, PPEF1 and MANBAL are potentially implicated in LOAD, with predicted links to calcium signalling and protein mannosylation. Our study demonstrates a highly injurious combination of TLR4-mediated NFKB signalling, NOROS inflammatory pathway activation, and mitochondrial dysfunction in LOAD. PMID:26202100

  19. Amarogentin regulates self renewal pathways to restrict liver carcinogenesis in experimental mouse model.

    PubMed

    Sur, Subhayan; Pal, Debolina; Banerjee, Kaustav; Mandal, Suvra; Das, Ashes; Roy, Anup; Panda, Chinmay Kumar

    2016-07-01

    Amarogentin, a secoiridoid glycoside isolated from medicinal plant Swertia chirata, was found to restrict CCl4 /N-nitrosodiethyl amine (NDEA) induced mouse liver carcinogenesis by modulating G1/S cell cycle check point and inducing apoptosis. To understand its therapeutic efficacy on stem cell self renewal pathways, prevalence of CD44 positive cancer stem cell (CSC) population, expressions (mRNA/protein) of some key regulatory genes of self renewal Wnt and Hedgehog pathways along with expressions of E-cadherin and EGFR were analyzed during the liver carcinogenesis and in liver cancer cell line HepG2. It was observed that amarogentin could significantly reduce CD44 positive CSCs in both pre and post initiation stages of carcinogenesis than carcinogen control mice. In Wnt pathway, amarogentin could inhibit expressions of β-catenin, phospho β-catenin (Y-654) and activate expressions of antagonists sFRP1/2 and APC in the liver lesions. In Hedgehog pathway, decreased expressions of Gli1, sonic hedgehog ligand, and SMO along with up-regulation of PTCH1 were seen in the liver lesions due to amarogentin treatment. Moreover, amarogentin could up-regulate E-cadherin expression and down-regulate expression of EGFR in the liver lesions. Similarly, amarogentin could inhibit HepG2 cell growth along with expression and prevalence of CD44 positive CSCs. Similar to in vivo analysis, amarogentin could modulate the expressions of the key regulatory genes of the Wnt and hedgehog pathways and EGFR in HepG2 cells. Thus, our data suggests that the restriction of liver carcinogenesis by amarogentin might be due to reduction of CD44 positive CSCs and modulation of the self renewal pathways. © 2015 Wiley Periodicals, Inc. PMID:26154024

  20. Degradation of Serotonin N-Acetyltransferase, a Circadian Regulator, by the N-end Rule Pathway.

    PubMed

    Wadas, Brandon; Borjigin, Jimo; Huang, Zheping; Oh, Jang-Hyun; Hwang, Cheol-Sang; Varshavsky, Alexander

    2016-08-12

    Serotonin N-acetyltransferase (AANAT) converts serotonin to N-acetylserotonin (NAS), a distinct biological regulator and the immediate precursor of melatonin, a circulating hormone that influences circadian processes, including sleep. N-terminal sequences of AANAT enzymes vary among vertebrates. Mechanisms that regulate the levels of AANAT are incompletely understood. Previous findings were consistent with the possibility that AANAT may be controlled through its degradation by the N-end rule pathway. By expressing the rat and human AANATs and their mutants not only in mammalian cells but also in the yeast Saccharomyces cerevisiae, and by taking advantage of yeast genetics, we show here that two "complementary" forms of rat AANAT are targeted for degradation by two "complementary" branches of the N-end rule pathway. Specifically, the N(α)-terminally acetylated (Nt-acetylated) Ac-AANAT is destroyed through the recognition of its Nt-acetylated N-terminal Met residue by the Ac/N-end rule pathway, whereas the non-Nt-acetylated AANAT is targeted by the Arg/N-end rule pathway, which recognizes the unacetylated N-terminal Met-Leu sequence of rat AANAT. We also show, by constructing lysine-to-arginine mutants of rat AANAT, that its degradation is mediated by polyubiquitylation of its Lys residue(s). Human AANAT, whose N-terminal sequence differs from that of rodent AANATs, is longer-lived than its rat counterpart and appears to be refractory to degradation by the N-end rule pathway. Together, these and related results indicate both a major involvement of the N-end rule pathway in the control of rodent AANATs and substantial differences in the regulation of rodent and human AANATs that stem from differences in their N-terminal sequences. PMID:27339900

  1. Association genetics and transcriptome analysis reveal a gibberellin-responsive pathway involved in regulating photosynthesis.

    PubMed

    Xie, Jianbo; Tian, Jiaxing; Du, Qingzhang; Chen, Jinhui; Li, Ying; Yang, Xiaohui; Li, Bailian; Zhang, Deqiang

    2016-05-01

    Gibberellins (GAs) regulate a wide range of important processes in plant growth and development, including photosynthesis. However, the mechanism by which GAs regulate photosynthesis remains to be understood. Here, we used multi-gene association to investigate the effect of genes in the GA-responsive pathway, as constructed by RNA sequencing, on photosynthesis, growth, and wood property traits, in a population of 435 Populus tomentosa By analyzing changes in the transcriptome following GA treatment, we identified many key photosynthetic genes, in agreement with the observed increase in measurements of photosynthesis. Regulatory motif enrichment analysis revealed that 37 differentially expressed genes related to photosynthesis shared two essential GA-related cis-regulatory elements, the GA response element and the pyrimidine box. Thus, we constructed a GA-responsive pathway consisting of 47 genes involved in regulating photosynthesis, including GID1, RGA, GID2, MYBGa, and 37 photosynthetic differentially expressed genes. Single nucleotide polymorphism (SNP)-based association analysis showed that 142 SNPs, representing 40 candidate genes in this pathway, were significantly associated with photosynthesis, growth, and wood property traits. Epistasis analysis uncovered interactions between 310 SNP-SNP pairs from 37 genes in this pathway, revealing possible genetic interactions. Moreover, a structural gene-gene matrix based on a time-course of transcript abundances provided a better understanding of the multi-gene pathway affecting photosynthesis. The results imply a functional role for these genes in mediating photosynthesis, growth, and wood properties, demonstrating the potential of combining transcriptome-based regulatory pathway construction and genetic association approaches to detect the complex genetic networks underlying quantitative traits. PMID:27091876

  2. Cortactin phosphorylation regulates cell invasion through a pH-dependent pathway

    PubMed Central

    Magalhaes, Marco A. O.; Larson, Daniel R.; Mader, Christopher C.; Bravo-Cordero, Jose Javier; Gil-Henn, Hava; Oser, Matthew; Chen, Xiaoming; Koleske, Anthony J.

    2011-01-01

    Invadopodia are invasive protrusions with proteolytic activity uniquely found in tumor cells. Cortactin phosphorylation is a key step during invadopodia maturation, regulating Nck1 binding and cofilin activity. The precise mechanism of cortactin-dependent cofilin regulation and the roles of this pathway in invadopodia maturation and cell invasion are not fully understood. We provide evidence that cortactin–cofilin binding is regulated by local pH changes at invadopodia that are mediated by the sodium–hydrogen exchanger NHE1. Furthermore, cortactin tyrosine phosphorylation mediates the recruitment of NHE1 to the invadopodium compartment, where it locally increases the pH to cause the release of cofilin from cortactin. We show that this mechanism involving cortactin phosphorylation, local pH increase, and cofilin activation regulates the dynamic cycles of invadopodium protrusion and retraction and is essential for cell invasion in 3D. Together, these findings identify a novel pH-dependent regulation of cell invasion. PMID:22105349

  3. Hedgehog pathway regulators influence cervical cancer cell proliferation, survival and migration

    SciTech Connect

    Samarzija, Ivana; Beard, Peter

    2012-08-17

    Highlights: Black-Right-Pointing-Pointer Unknown cellular mutations complement papillomavirus-induced carcinogenesis. Black-Right-Pointing-Pointer Hedgehog pathway components are expressed by cervical cancer cells. Black-Right-Pointing-Pointer Hedgehog pathway activators and inhibitors regulate cervical cancer cell biology. Black-Right-Pointing-Pointer Cell immortalization by papillomavirus and activation of Hedgehog are independent. -- Abstract: Human papillomavirus (HPV) infection is considered to be a primary hit that causes cervical cancer. However, infection with this agent, although needed, is not sufficient for a cancer to develop. Additional cellular changes are required to complement the action of HPV, but the precise nature of these changes is not clear. Here, we studied the function of the Hedgehog (Hh) signaling pathway in cervical cancer. The Hh pathway can have a role in a number of cancers, including those of liver, lung and digestive tract. We found that components of the Hh pathway are expressed in several cervical cancer cell lines, indicating that there could exists an autocrine Hh signaling loop in these cells. Inhibition of Hh signaling reduces proliferation and survival of the cervical cancer cells and induces their apoptosis as seen by the up-regulation of the pro-apoptotic protein cleaved caspase 3. Our results indicate that Hh signaling is not induced directly by HPV-encoded proteins but rather that Hh-activating mutations are selected in cells initially immortalized by HPV. Sonic Hedgehog (Shh) ligand induces proliferation and promotes migration of the cervical cancer cells studied. Together, these results indicate pro-survival and protective roles of an activated Hh signaling pathway in cervical cancer-derived cells, and suggest that inhibition of this pathway may be a therapeutic option in fighting cervical cancer.

  4. Non-conventional trafficking of the cystic fibrosis transmembrane conductance regulator through the early secretory pathway.

    PubMed

    Yoo, Jin-San; Moyer, Bryan D; Bannykh, Sergei; Yoo, Hyeon-Mi; Riordan, John R; Balch, William E

    2002-03-29

    The mechanism(s) of cystic fibrosis transmembrane conductance regulator (CFTR) trafficking from the endoplasmic reticulum (ER) through the Golgi apparatus, the step impaired in individuals afflicted with the prevalent CFTR-DeltaF508 mutation leading to cystic fibrosis, is largely unknown. Recent morphological observations suggested that CFTR is largely absent from the Golgi in situ (Bannykh, S. I., Bannykh, G. I., Fish, K. N., Moyer, B. D., Riordan, J. R., and Balch, W. E. (2000) Traffic 1, 852-870), raising the possibility of a novel trafficking pathway through the early secretory pathway. We now report that export of CFTR from the ER is regulated by the conventional coat protein complex II (COPII) in all cell types tested. Remarkably, in a cell type-specific manner, processing of CFTR from the core-glycosylated (band B) ER form to the complex-glycosylated (band C) isoform followed a non-conventional pathway that was insensitive to dominant negative Arf1, Rab1a/Rab2 GTPases, or the SNAp REceptor (SNARE) component syntaxin 5, all of which block the conventional trafficking pathway from the ER to the Golgi. Moreover, CFTR transport through the non-conventional pathway was potently blocked by overexpression of the late endosomal target-SNARE syntaxin 13, suggesting that recycling through a late Golgi/endosomal system was a prerequisite for CFTR maturation. We conclude that CFTR transport in the early secretory pathway can involve a novel pathway between the ER and late Golgi/endosomal compartments that may influence developmental expression of CFTR on the cell surface in polarized epithelial cells. PMID:11799116

  5. BRAFV600E Negatively Regulates the AKT Pathway in Melanoma Cell Lines

    PubMed Central

    Chen, Brenden; Tardell, Christine; Higgins, Brian; Packman, Kathryn; Boylan, John F.; Niu, Huifeng

    2012-01-01

    Cross-feedback activation of MAPK and AKT pathways is implicated as a resistance mechanism for cancer therapeutic agents targeting either RAF/MEK or PI3K/AKT/mTOR. It is thus important to have a better understanding of the molecular resistance mechanisms to improve patient survival benefit from these agents. Here we show that BRAFV600E is a negative regulator of the AKT pathway. Expression of BRAFV600E in NIH3T3 cells significantly suppresses MEK inhibitor (RG7167) or mTORC1 inhibitor (rapamycin) induced AKT phosphorylation (pAKT) and downstream signal activation. Treatment-induced pAKT elevation is found in BRAF wild type melanoma cells but not in a subset of melanoma cell lines harboring BRAFV600E. Knock-down of BRAFV600E in these melanoma cells elevates basal pAKT and downstream signals, whereas knock-down of CRAF, MEK1/2 or ERK1/2 or treatment with a BRAF inhibitor have no impact on pAKT. Mechanistically, we show that BRAFV600E interacts with rictor complex (mTORC2) and regulates pAKT through mTORC2. BRAFV600E is identified in mTORC2 after immunoprecipitation of rictor. Knock-down of rictor abrogates BRAFV600E depletion induced pAKT. Knock-down of BRAFV600E enhances cellular enzyme activity of mTORC2. Aberrant activation of AKT pathway by PTEN loss appears to override the negative impact of BRAFV600E on pAKT. Taken together, our findings suggest that in a subset of BRAFV600E melanoma cells, BRAFV600E negatively regulates AKT pathway in a rictor-dependent, MEK/ERK and BRAF kinase-independent manner. Our study reveals a novel molecular mechanism underlying the regulation of feedback loops between the MAPK and AKT pathways. PMID:22880048

  6. BRAFV600E negatively regulates the AKT pathway in melanoma cell lines.

    PubMed

    Chen, Brenden; Tardell, Christine; Higgins, Brian; Packman, Kathryn; Boylan, John F; Niu, Huifeng

    2012-01-01

    Cross-feedback activation of MAPK and AKT pathways is implicated as a resistance mechanism for cancer therapeutic agents targeting either RAF/MEK or PI3K/AKT/mTOR. It is thus important to have a better understanding of the molecular resistance mechanisms to improve patient survival benefit from these agents. Here we show that BRAFV600E is a negative regulator of the AKT pathway. Expression of BRAFV600E in NIH3T3 cells significantly suppresses MEK inhibitor (RG7167) or mTORC1 inhibitor (rapamycin) induced AKT phosphorylation (pAKT) and downstream signal activation. Treatment-induced pAKT elevation is found in BRAF wild type melanoma cells but not in a subset of melanoma cell lines harboring BRAFV600E. Knock-down of BRAFV600E in these melanoma cells elevates basal pAKT and downstream signals, whereas knock-down of CRAF, MEK1/2 or ERK1/2 or treatment with a BRAF inhibitor have no impact on pAKT. Mechanistically, we show that BRAFV600E interacts with rictor complex (mTORC2) and regulates pAKT through mTORC2. BRAFV600E is identified in mTORC2 after immunoprecipitation of rictor. Knock-down of rictor abrogates BRAFV600E depletion induced pAKT. Knock-down of BRAFV600E enhances cellular enzyme activity of mTORC2. Aberrant activation of AKT pathway by PTEN loss appears to override the negative impact of BRAFV600E on pAKT. Taken together, our findings suggest that in a subset of BRAFV600E melanoma cells, BRAFV600E negatively regulates AKT pathway in a rictor-dependent, MEK/ERK and BRAF kinase-independent manner. Our study reveals a novel molecular mechanism underlying the regulation of feedback loops between the MAPK and AKT pathways. PMID:22880048

  7. Global transcriptome analysis reveals circadian regulation of key pathways in plant growth and development

    PubMed Central

    Covington, Michael F; Maloof, Julin N; Straume, Marty; Kay, Steve A; Harmer, Stacey L

    2008-01-01

    Background As nonmotile organisms, plants must rapidly adapt to ever-changing environmental conditions, including those caused by daily light/dark cycles. One important mechanism for anticipating and preparing for such predictable changes is the circadian clock. Nearly all organisms have circadian oscillators that, when they are in phase with the Earth's rotation, provide a competitive advantage. In order to understand how circadian clocks benefit plants, it is necessary to identify the pathways and processes that are clock controlled. Results We have integrated information from multiple circadian microarray experiments performed on Arabidopsis thaliana in order to better estimate the fraction of the plant transcriptome that is circadian regulated. Analyzing the promoters of clock-controlled genes, we identified circadian clock regulatory elements correlated with phase-specific transcript accumulation. We have also identified several physiological pathways enriched for clock-regulated changes in transcript abundance, suggesting they may be modulated by the circadian clock. Conclusion Our analysis suggests that transcript abundance of roughly one-third of expressed A. thaliana genes is circadian regulated. We found four promoter elements, enriched in the promoters of genes with four discrete phases, which may contribute to the time-of-day specific changes in the transcript abundance of these genes. Clock-regulated genes are over-represented among all of the classical plant hormone and multiple stress response pathways, suggesting that all of these pathways are influenced by the circadian clock. Further exploration of the links between the clock and these pathways will lead to a better understanding of how the circadian clock affects plant growth and leads to improved fitness. PMID:18710561

  8. Directional Regulation of Enzyme Pathways through the Control of Substrate Channeling on a DNA Origami Scaffold.

    PubMed

    Ke, Guoliang; Liu, Minghui; Jiang, Shuoxing; Qi, Xiaodong; Yang, Yuhe Renee; Wootten, Shaun; Zhang, Fei; Zhu, Zhi; Liu, Yan; Yang, Chaoyong James; Yan, Hao

    2016-06-20

    Artificial multi-enzyme systems with precise and dynamic control over the enzyme pathway activity are of great significance in bionanotechnology and synthetic biology. Herein, we exploit a spatially addressable DNA nanoplatform for the directional regulation of two enzyme pathways (G6pDH-MDH and G6pDH-LDH) through the control of NAD(+) substrate channeling by specifically shifting NAD(+) between the two enzyme pairs. We believe that this concept will be useful for the design of regulatory biological circuits for synthetic biology and biomedicine. PMID:27159899

  9. Utilization of economical substrate-derived carbohydrates by solventogenic clostridia: pathway dissection, regulation and engineering.

    PubMed

    Gu, Yang; Jiang, Yu; Yang, Sheng; Jiang, Weihong

    2014-10-01

    Solventogenic clostridia can produce acetone, butanol and ethanol (ABE) by using different carbohydrates. For economical reasons, the utilization of cheap and renewable biomass in clostridia-based ABE fermentation has recently attracted increasing interests. With the study of molecular microbiology and development of genetic tools, the understanding of carbohydrate metabolism in clostridia has increased in recent years. Here, we review the pioneering work in this field, with a focus on dissecting the pathways and describing the regulation of the metabolism of economical substrate-derived carbohydrates by clostridia. Recent progress in the metabolic engineering of carbohydrate utilization pathways is also described. PMID:24769507

  10. Regulation and Role of TGFβ Signaling Pathway in Aging and Osteoarthritis Joints

    PubMed Central

    Baugé, Catherine; Girard, Nicolas; Lhuissier, Eva; Bazille, Celine; Boumediene, Karim

    2014-01-01

    Transforming growth factor beta (TGFβ) is a major signalling pathway in joints. This superfamilly is involved in numerous cellular processes in cartilage. Usually, they are considered to favor chondrocyte differentiation and cartilage repair. However, other studies show also deleterious effects of TGFβ which may induce hypertrophy. This may be explained at least in part by alteration of TGFβ signaling pathways in aging chondrocytes. This review focuses on the functions of TGFβ in joints and the regulation of its signaling mediators (receptors, Smads) during aging and osteoarthritis. PMID:25489490

  11. Regulation of innate immune signalling pathways by the tripartite motif (TRIM) family proteins

    PubMed Central

    Kawai, Taro; Akira, Shizuo

    2011-01-01

    The innate immune system recognizes microbial components through pattern-recognition receptors (PRRs), including membrane-bound Toll-like receptors and cytosolic receptors such as RIG-I-like receptors and deoxyribonucleic acid (DNA) sensors. These PRRs trigger distinct signal transduction pathways that culminate in induction of an array of cytokines and other mediators required for host defense. The tripartite motif (TRIM) family is a diverse family of RING finger domain-containing proteins, which are involved in a variety of cellular functions. Importantly, recent studies have shown that they are also involved in the regulation of innate immune responses through the modulation of PRR signalling pathways. PMID:21826793

  12. Regulation of necrotic cell death: p53, PARP1 and cyclophilin D-overlapping pathways of regulated necrosis?

    PubMed

    Ying, Yuan; Padanilam, Babu J

    2016-06-01

    In contrast to apoptosis and autophagy, necrotic cell death was considered to be a random, passive cell death without definable mediators. However, this dogma has been challenged by recent developments suggesting that necrotic cell death can also be a regulated process. Regulated necrosis includes multiple cell death modalities such as necroptosis, parthanatos, ferroptosis, pyroptosis, and mitochondrial permeability transition pore (MPTP)-mediated necrosis. Several distinctive executive molecules, particularly residing on the mitochondrial inner and outer membrane, amalgamating to form the MPTP have been defined. The c-subunit of the F1F0ATP synthase on the inner membrane and Bax/Bak on the outer membrane are considered to be the long sought components that form the MPTP. Opening of the MPTP results in loss of mitochondrial inner membrane potential, disruption of ATP production, increased ROS production, organelle swelling, mitochondrial dysfunction and consequent necrosis. Cyclophilin D, along with adenine nucleotide translocator and the phosphate carrier are considered to be important regulators involved in the opening of MPTP. Increased production of ROS can further trigger other necrotic pathways mediated through molecules such as PARP1, leading to irreversible cell damage. This review examines the roles of PARP1 and cyclophilin D in necrotic cell death. The hierarchical role of p53 in regulation and integration of key components of signaling pathway to elicit MPTP-mediated necrosis and ferroptosis is explored. In the context of recent insights, the indistinct role of necroptosis signaling in tubular necrosis after ischemic kidney injury is scrutinized. We conclude by discussing the participation of p53, PARP1 and cyclophilin D and their overlapping pathways to elicit MPTP-mediated necrosis and ferroptosis in acute kidney injury. PMID:27048819

  13. Postprandial regulation of hepatic microRNAs predicted to target the insulin pathway in rainbow trout.

    PubMed

    Mennigen, Jan A; Panserat, Stéphane; Larquier, Mélanie; Plagnes-Juan, Elisabeth; Medale, Françoise; Seiliez, Iban; Skiba-Cassy, Sandrine

    2012-01-01

    Rainbow trout are carnivorous fish and poor metabolizers of carbohydrates, which established this species as a model organism to study the comparative physiology of insulin. Following the recent characterisation of key roles of several miRNAs in the insulin action on hepatic intermediary metabolism in mammalian models, we investigated the hypothesis that hepatic miRNA expression is postprandially regulated in the rainbow trout and temporally coordinated in the context of insulin-mediated regulation of metabolic gene expression in the liver. To address this hypothesis, we used a time-course experiment in which rainbow trout were fed a commercial diet after short-term fasting. We investigated hepatic miRNA expression, activation of the insulin pathway, and insulin regulated metabolic target genes at several time points. Several miRNAs which negatively regulate hepatic insulin signaling in mammalian model organisms were transiently increased 4 h after the meal, consistent with a potential role in acute postprandial negative feed-back regulation of the insulin pathway and attenuation of gluconeogenic gene expression. We equally observed a transient increase in omy- miRNA-33 and omy-miRNA-122b 4 h after feeding, whose homologues have potent lipogenic roles in the liver of mammalian model systems. A concurrent increase in the activity of the hepatic insulin signaling pathway and the expression of lipogenic genes (srebp1c, fas, acly) was equally observed, while lipolytic gene expression (cpt1a and cpt1b) decreased significantly 4 h after the meal. This suggests lipogenic roles of omy-miRNA-33 and omy-miRNA-122b may be conserved between rainbow trout and mammals and that these miRNAs may furthermore contribute to acute postprandial regulation of de novo hepatic lipid synthesis in rainbow trout. These findings provide a framework for future research of miRNA regulation of hepatic metabolism in trout and will help to further elucidate the metabolic phenotype of rainbow trout

  14. The N-end rule pathway regulates pathogen responses in plants.

    PubMed

    de Marchi, Rémi; Sorel, Maud; Mooney, Brian; Fudal, Isabelle; Goslin, Kevin; Kwaśniewska, Kamila; Ryan, Patrick T; Pfalz, Marina; Kroymann, Juergen; Pollmann, Stephan; Feechan, Angela; Wellmer, Frank; Rivas, Susana; Graciet, Emmanuelle

    2016-01-01

    To efficiently counteract pathogens, plants rely on a complex set of immune responses that are tightly regulated to allow the timely activation, appropriate duration and adequate amplitude of defense programs. The coordination of the plant immune response is known to require the activity of the ubiquitin/proteasome system, which controls the stability of proteins in eukaryotes. Here, we demonstrate that the N-end rule pathway, a subset of the ubiquitin/proteasome system, regulates the defense against a wide range of bacterial and fungal pathogens in the model plant Arabidopsis thaliana. We show that this pathway positively regulates the biosynthesis of plant-defense metabolites such as glucosinolates, as well as the biosynthesis and response to the phytohormone jasmonic acid, which plays a key role in plant immunity. Our results also suggest that the arginylation branch of the N-end rule pathway regulates the timing and amplitude of the defense program against the model pathogen Pseudomonas syringae AvrRpm1. PMID:27173012

  15. Regulation of the retinoblastoma-E2F pathway by the ubiquitin-proteasome system.

    PubMed

    Sengupta, Satyaki; Henry, R William

    2015-10-01

    The retinoblastoma tumor suppressor (RB) and its related family members p107 and p130 regulate cell proliferation through the transcriptional repression of genes involved in cellular G1 to S phase transition. However, RB proteins are functionally versatile, and numerous genetic and biochemical studies point to expansive roles in cellular growth control, pluripotency, and apoptotic response. For the vast majority of genes, RB family members target the E2F family of transcriptional activators as an integral component of its gene regulatory mechanism. These interactions are regulated via reversible phosphorylation by Cyclin/Cyclin-dependent kinase (Cdk) complexes, a major molecular mechanism that regulates transcriptional output of RB/E2F target genes. Recent studies indicate an additional level of regulation involving the ubiquitin-proteasome system that renders pervasive control over each component of the RB pathway. Disruption of the genetic circuitry for proteasome-mediated targeting of the RB pathway has serious consequences on development and cellular transformation, and is associated with several forms of human cancer. In this review, we discuss the role of the ubiquitin-proteasome system in proteolytic control of RB-E2F pathway components, and recent data that points to surprising non-proteolytic roles for the ubiquitin-proteasome system in novel transcriptional regulatory mechanisms. PMID:26319102

  16. The N-end rule pathway regulates pathogen responses in plants

    PubMed Central

    de Marchi, Rémi; Sorel, Maud; Mooney, Brian; Fudal, Isabelle; Goslin, Kevin; Kwaśniewska, Kamila; Ryan, Patrick T.; Pfalz, Marina; Kroymann, Juergen; Pollmann, Stephan; Feechan, Angela; Wellmer, Frank; Rivas, Susana; Graciet, Emmanuelle

    2016-01-01

    To efficiently counteract pathogens, plants rely on a complex set of immune responses that are tightly regulated to allow the timely activation, appropriate duration and adequate amplitude of defense programs. The coordination of the plant immune response is known to require the activity of the ubiquitin/proteasome system, which controls the stability of proteins in eukaryotes. Here, we demonstrate that the N-end rule pathway, a subset of the ubiquitin/proteasome system, regulates the defense against a wide range of bacterial and fungal pathogens in the model plant Arabidopsis thaliana. We show that this pathway positively regulates the biosynthesis of plant-defense metabolites such as glucosinolates, as well as the biosynthesis and response to the phytohormone jasmonic acid, which plays a key role in plant immunity. Our results also suggest that the arginylation branch of the N-end rule pathway regulates the timing and amplitude of the defense program against the model pathogen Pseudomonas syringae AvrRpm1. PMID:27173012

  17. Methionine sulfoxide reductase A regulates cell growth through the p53-p21 pathway

    SciTech Connect

    Choi, Seung Hee; Kim, Hwa-Young

    2011-12-09

    Highlights: Black-Right-Pointing-Pointer Down-regulation of MsrA inhibits normal cell proliferation. Black-Right-Pointing-Pointer MsrA deficiency leads to an increase in p21 by enhanced p53 acetylation. Black-Right-Pointing-Pointer Down-regulation of MsrA causes cell cycle arrest at the G{sub 2}/M stage. Black-Right-Pointing-Pointer MsrA is a regulator of cell growth that mediates the p53-p21 pathway. -- Abstract: MsrA is an oxidoreductase that catalyzes the stereospecific reduction of methionine-S-sulfoxide to methionine. Although MsrA is well-characterized as an antioxidant and has been implicated in the aging process and cellular senescence, its roles in cell proliferation are poorly understood. Here, we report a critical role of MsrA in normal cell proliferation and describe the regulation mechanism of cell growth by this protein. Down-regulation of MsrA inhibited cell proliferation, but MsrA overexpression did not promote it. MsrA deficiency led to an increase in p21, a major cyclin-dependent kinase inhibitor, thereby causing cell cycle arrest at the G{sub 2}/M stage. While protein levels of p53 were not altered upon MsrA deficiency, its acetylation level was significantly elevated, which subsequently activated p21 transcription. The data suggest that MsrA is a regulator of cell growth that mediates the p53-p21 pathway.

  18. Prolyl isomerase Pin1 regulated signaling pathway revealed by Pin1 +/+ and Pin1 -/- mouse embryonic fibroblast cells.

    PubMed

    Huang, Guo-Liang; Qiu, Jin-Hua; Li, Bin-Bin; Wu, Jing-Jing; Lu, Yan; Liu, Xing-Yan; He, Zhiwei

    2013-10-01

    Pin1 (peptidylprolyl cis/trans isomerase, NIMA-interacting 1) plays a key role in a number of diseases including cancer and Alzheimer disease. Previous studies have identified a wide range of phosphoproteins as Pin1 substrates. Related pathways were analyzed separately. The aim of this study was to provide a comprehensive picture involving Pin1 regulation. A genome-wide mRNA expression microarray was carried out using the RNA isolation from Pin1 (+/+) and Pin1 (-/-) mouse embryonic fibroblast (MEF) cells. Signaling pathways regulated by Pin1 were analyzed with the utility of KEGG pathway and GO annotation. An expression pattern regulated by Pin1 was revealed. A total of 606 genes, 375 being up-regulated and 231 down-regulated, were differentially expressed when comparing Pin1 +/+ to Pin1 -/- MEF cells. Totally 48 pathways were shown to be regulated by Pin1 expression in KEGG pathway analysis. In the GO annotation system, 19 processes on biological processes, 15 processes on cellular components, and 18 processes on molecular functions were found to be in the regulation of Pin1 expression. Pathways related to immune system and cancer showed most significant association with Pin1 regulation. Pin1 is an important regulator in a wide range of signaling pathways that were related to immune system and cancer. PMID:23563987

  19. The TOR signaling pathway regulates starvation-induced pseudouridylation of yeast U2 snRNA.

    PubMed

    Wu, Guowei; Radwan, Mohamed K; Xiao, Mu; Adachi, Hironori; Fan, Jason; Yu, Yi-Tao

    2016-08-01

    Pseudouridine (Ψ) has been identified in various types of RNAs, including mRNA, rRNA, tRNA, snRNA, and many other noncoding RNAs. We have previously shown that RNA pseudouridylation, like DNA and protein modifications, can be induced by stress. For instance, growing yeast cells to saturation induces the formation of Ψ93 in U2 snRNA. Here, we further investigate this inducible RNA modification. We show that switching yeast cells from nutrient-rich medium to different nutrient-deprived media (including water) results in the formation of Ψ93 in U2 snRNA. Using gene deletion/conditional depletion as well as rapamycin treatment, we further show that the TOR signaling pathway, which controls cell entry into stationary phase, regulates Ψ93 formation. The RAS/cAMP signaling pathway, which parallels the TOR pathway, plays no role in this inducible modification. PMID:27268497

  20. Aristolochia Manshuriensis Kom Inhibits Adipocyte Differentiation by Regulation of ERK1/2 and Akt Pathway

    PubMed Central

    Kwak, Dong Hoon; Lee, Ji-Hye; Kim, Taesoo; Ahn, Hyo Sun; Cho, Won-Kyung; Ha, Hyunil; Hwang, Youn-Hwan; Ma, Jin Yeul

    2012-01-01

    Aristolochia manshuriensis Kom (AMK) is a traditional medicinal herb used for the treatment of arthritis, rheumatism, hepatitis, and anti-obesity. Because of nephrotoxicity and carcinogenicity of AMK, there are no pharmacological reports on anti-obesity potential of AMK. Here, we showed AMK has an inhibitory effect on adipocyte differentiation of 3T3-L1 cells along with significantly decrease in the lipid accumulation by downregulating several adipocyte-specific transcription factors including peroxisome proliferation-activity receptor γ (PPAR-γ), CCAAT/enhancer binding protein α (C/EBP-α) and C/EBP-β, which are critical for adipogenesis in vitro. AMK also markedly activated the extracellular signal-regulated protein kinase 1/2 (ERK1/2) pathway including Ras, Raf1, and mitogen-activated protein kinase kinase 1 (MEK1), and significantly suppressed Akt pathway by inhibition of phosphoinositide-dependent kinase 1 (PDK1). Aristolochic acid (AA) and ethyl acetate (EtOAc) fraction of AMK with AA were significantly inhibited TG accumulation, and regulated two pathway (ERK1/2 and Akt) during adipocyte differentiation, and was not due to its cytotoxicity. These two pathways were upstream of PPAR-γ and C/EBPα in the adipogenesis. In addition, gene expressions of secreting factors such as fatty acid synthase (FAS), adiponectin, lipopreotein lipase (LPL), and aP2 were significantly inhibited by treatment of AMK during adipogenesis. We used the high-fat diet (HFD)-induced obesity mouse model to determine the inhibitory effects of AMK on obesity. Oral administration of AMK (62.5 mg/kg/day) significantly decreased the fat tissue weight, total cholesterol (TC), and low density lipoprotein-cholesterol (LDL-C) concentration in the blood. The results of this study suggested that AMK inhibited lipid accumulation by the down-regulation of the major transcription factors of the adipogensis pathway including PPAR-γ and C/EBP-α through regulation of Akt pathway and ERK 1

  1. Differential expression of the regulated catecholamine secretory pathway in different hereditary forms of pheochromocytoma

    PubMed Central

    Eisenhofer, Graeme; Huynh, Thanh-Truc; Elkahloun, Abdel; Morris, John C.; Bratslavsky, Gennady; Linehan, W. Marston; Zhuang, Zhengping; Balgley, Brian M.; Lee, Cheng S.; Mannelli, Massimo; Lenders, Jacques W. M.; Bornstein, Stefan R.; Pacak, Karel

    2008-01-01

    Pheochromocytomas in patients with von Hippel-Lindau (VHL) syndrome and multiple endocrine neoplasia type 2 (MEN 2) differ in the types and amounts of catecholamines produced and the resulting signs and symptoms. We hypothesized the presence of different processes of catecholamine release reflecting differential expression of components of the regulated secretory pathway among the two types of hereditary tumors. Differences in catecholamine secretion from tumors in patients with VHL syndrome (n = 47) and MEN 2 (n = 32) were examined using measurements of catecholamines in tumor tissue, urine, and plasma, the last of which was under baseline conditions in all subjects and in a subgroup of patients who received intravenous glucagon to provoke catecholamine release. Microarray and proteomics analyses, quantitative PCR, and Western blotting were used to assess expression of tumor tissue secretory pathway components. The rate constant for baseline catecholamine secretion was 20-fold higher in VHL than in MEN 2 tumors (0.359 ± 0.094 vs. 0.018 ± 0.009 day−1), but catecholamine release was responsive only to glucagon in MEN 2 tumors. Compared with tumors from MEN 2 patients, those from VHL patients were characterized by reduced expression of numerous components of the regulated secretory pathway (e.g., SNAP25, syntaxin, rabphilin 3A, annexin A7, calcium-dependent secretion activator). The mutation-dependent differences in expression of secretory pathway components indicate a more mature regulated secretory pathway in MEN 2 than VHL tumors. These data provide a unique mechanistic link to explain how variations in the molecular machinery governing exocytosis may contribute to clinical differences in the secretion of neurotransmitters or hormones and the subsequent presentation of a disease. PMID:18854424

  2. Differential expression of the regulated catecholamine secretory pathway in different hereditary forms of pheochromocytoma.

    PubMed

    Eisenhofer, Graeme; Huynh, Thanh-Truc; Elkahloun, Abdel; Morris, John C; Bratslavsky, Gennady; Linehan, W Marston; Zhuang, Zhengping; Balgley, Brian M; Lee, Cheng S; Mannelli, Massimo; Lenders, Jacques W M; Bornstein, Stefan R; Pacak, Karel

    2008-11-01

    Pheochromocytomas in patients with von Hippel-Lindau (VHL) syndrome and multiple endocrine neoplasia type 2 (MEN 2) differ in the types and amounts of catecholamines produced and the resulting signs and symptoms. We hypothesized the presence of different processes of catecholamine release reflecting differential expression of components of the regulated secretory pathway among the two types of hereditary tumors. Differences in catecholamine secretion from tumors in patients with VHL syndrome (n = 47) and MEN 2 (n = 32) were examined using measurements of catecholamines in tumor tissue, urine, and plasma, the last of which was under baseline conditions in all subjects and in a subgroup of patients who received intravenous glucagon to provoke catecholamine release. Microarray and proteomics analyses, quantitative PCR, and Western blotting were used to assess expression of tumor tissue secretory pathway components. The rate constant for baseline catecholamine secretion was 20-fold higher in VHL than in MEN 2 tumors (0.359 +/- 0.094 vs. 0.018 +/- 0.009 day(-1)), but catecholamine release was responsive only to glucagon in MEN 2 tumors. Compared with tumors from MEN 2 patients, those from VHL patients were characterized by reduced expression of numerous components of the regulated secretory pathway (e.g., SNAP25, syntaxin, rabphilin 3A, annexin A7, calcium-dependent secretion activator). The mutation-dependent differences in expression of secretory pathway components indicate a more mature regulated secretory pathway in MEN 2 than VHL tumors. These data provide a unique mechanistic link to explain how variations in the molecular machinery governing exocytosis may contribute to clinical differences in the secretion of neurotransmitters or hormones and the subsequent presentation of a disease. PMID:18854424

  3. The orphan GPCR, Gpr161, regulates the retinoic acid and canonical Wnt pathways during neurulation.

    PubMed

    Li, Bo I; Matteson, Paul G; Ababon, Myka F; Nato, Alejandro Q; Lin, Yong; Nanda, Vikas; Matise, Tara C; Millonig, James H

    2015-06-01

    The vacuolated lens (vl) mouse mutation arose on the C3H/HeSnJ background and results in lethality, neural tube defects (NTDs) and cataracts. The vl phenotypes are due to a deletion/frameshift mutation in the orphan GPCR, Gpr161. A recent study using a null allele demonstrated that Gpr161 functions in primary cilia and represses the Shh pathway. We show the hypomorphic Gpr161(vl) allele does not severely affect the Shh pathway. To identify additional pathways regulated by Gpr161 during neurulation, we took advantage of naturally occurring genetic variation in the mouse. Previously Gpr161(vl-C3H) was crossed to different inbred backgrounds including MOLF/EiJ and the Gpr161(vl) mutant phenotypes were rescued. Five modifiers were mapped (Modvl: Modifier of vl) including Modvl5(MOLF). In this study we demonstrate the Modvl5(MOLF) congenic rescues the Gpr161(vl)-associated lethality and NTDs but not cataracts. Bioinformatics determined the transcription factor, Cdx1, is the only annotated gene within the Modvl5 95% CI co-expressed with Gpr161 during neurulation and not expressed in the eye. Using Cdx1 as an entry point, we identified the retinoid acid (RA) and canonical Wnt pathways as downstream targets of Gpr161. QRT-PCR, ISH and IHC determined that expression of RA and Wnt genes are down-regulated in Gpr161(vl/vl) but rescued by the Modvl5(MOLF) congenic during neurulation. Intraperitoneal RA injection restores expression of canonical Wnt markers and rescues Gpr161(vl/vl) NTDs. These results establish the RA and canonical Wnt as pathways downstream of Gpr161 during neurulation, and suggest that Modvl5(MOLF) bypasses the Gpr161(vl) mutation by restoring the activity of these pathways. PMID:25753732

  4. Essential Role of TGF-β/Smad Pathway on Statin Dependent Vascular Smooth Muscle Cell Regulation

    PubMed Central

    Rodríguez-Vita, Juan; Sánchez-Galán, Eva; Santamaría, Beatriz; Sánchez-López, Elsa; Rodrigues-Díez, Raquel; Blanco-Colio, Luís Miguel; Egido, Jesús; Ortiz, Alberto; Ruiz-Ortega, Marta

    2008-01-01

    Background The 3-hydroxy-3-methylglutaryl CoA reductase inhibitors (also called statins) exert proven beneficial effects on cardiovascular diseases. Recent data suggest a protective role for Transforming Growth Factor-β (TGF-β) in atherosclerosis by regulating the balance between inflammation and extracellular matrix accumulation. However, there are no studies about the effect of statins on TGF-β/Smad pathway in atherosclerosis and vascular cells. Methodology In cultured vascular smooth muscle cells (VSMCs) statins enhanced Smad pathway activation caused by TGF-β. In addition, statins upregulated TGF-β receptor type II (TRII), and increased TGF-β synthesis and TGF-β/Smad-dependent actions. In this sense, statins, through Smad activation, render VSMCs more susceptible to TGF-β induced apoptosis and increased TGF-β-mediated ECM production. It is well documented that high doses of statins induce apoptosis in cultured VSMC in the presence of serum; however the precise mechanism of this effect remains to be elucidated. We have found that statins-induced apoptosis was mediated by TGF-β/Smad pathway. Finally, we have described that RhoA inhibition is a common intracellular mechanisms involved in statins effects. The in vivo relevance of these findings was assessed in an experimental model of atherosclerosis in apolipoprotein E deficient mice: Treatment with Atorvastatin increased Smad3 phosphorylation and TRII overexpression, associated to elevated ECM deposition in the VSMCs within atheroma plaques, while apoptosis was not detected. Conclusions Statins enhance TGF-β/Smad pathway, regulating ligand levels, receptor, main signaling pathway and cellular responses of VSMC, including apoptosis and ECM accumulation. Our findings show that TGF-β/Smad pathway is essential for statins-dependent actions in VSMCs. PMID:19088845

  5. Adiponectin Regulates Vascular Endothelial Growth Factor-C Expression in Macrophages via Syk-ERK Pathway

    PubMed Central

    Hu, Di; Fukuhara, Atsunori; Miyata, Yugo; Yokoyama, Chieko; Otsuki, Michio; Kihara, Shinji; Shimomura, Iichiro

    2013-01-01

    Adiponectin is exclusively expressed in adipose tissues and exhibits protective effects against cardiovascular and metabolic diseases. It enhances AMP-activated kinase (AMPK) and peroxisome proliferator-activated receptor α (PPARα) signaling in the liver and skeletal muscles, however, its signaling pathways in macrophages remain to be elucidated. Here, we show that adiponectin upregulated the expression of vascular endothelial growth factor (VEGF)-C, and induced phosphorylation of extracellular signal-regulated kinase (ERK) in macrophages. Inhibition of Syk abrogated adiponectin-induced VEGF-C expression and ERK phosphorylation. Furthermore, inhibition of ERK blocked the induction of VEGF-C gene. Inhibition of Syk, but not that of ERK, abrogated adiponectin-induced expression of cyclooxygenase (COX)-2, tissue inhibitor of metalloproteinase (TIMP)-1, and interleukin (IL)-6. These results indicate that adiponectin regulates VEGF-C expression via Syk-ERK pathway in macrophages. PMID:23424645

  6. Regulation of Hydroxylation and Nitroreduction Pathways during Metabolism of the Neonicotinoid Insecticide Imidacloprid by Pseudomonas putida.

    PubMed

    Lu, Tian-Qi; Mao, Shi-Yun; Sun, Shi-Lei; Yang, Wen-Long; Ge, Feng; Dai, Yi-Jun

    2016-06-22

    Imidacloprid (IMI) is mainly metabolized via nitroreduction and hydroxylation pathways, which produce different metabolites that are toxic to mammals and insects. However, regulation of IMI metabolic flux between nitroreduction and hydroxylation pathways is still unclear. In this study, Pseudomonas putida was found to metabolize IMI to 5-hydroxy and nitroso IMI and was therefore used for investigating the regulation of IMI metabolic flux. The cell growth time, cosubstrate, dissolved oxygen concentration, and pH showed significant effect on IMI degradation and nitroso and 5-hydroxy IMI formation. Gene cloning and overexpression in Escherichia coli proved that P. putida KT2440 aldehyde oxidase mediated IMI nitroreduction to nitroso IMI, while cytochrome P450 monooxygenase (CYP) failed to improve IMI hydroxylation. Moreover, E. coli cells without CYP could hydroxylate IMI, demonstrating the role of a non-CYP enzyme in IMI hydroxylation. Thus, the present study helps to further understand the environmental fate of IMI and its underlying mechanism. PMID:27230024

  7. TRIM29 regulates the p63-mediated pathway in cervical cancer cells.

    PubMed

    Masuda, Yasushi; Takahashi, Hidehisa; Hatakeyama, Shigetsugu

    2015-10-01

    Cell invasion and adhesion play an important role in cancer metastasis and are orchestrated by a complicated network of transcription factors including p63. Here, we show that a member of the tripartite motif protein family, TRIM29, is required for regulation of the p63-mediated pathway in cervical cancer cells. TRIM29 knockdown alters the adhesion and invasion activities of cervical cancer cells. TRIM29 knockdown and overexpression cause a significant decrease and increase of TAp63α expression, respectively. TRIM29 knockdown alters the expression pattern of integrins and increases ZEB1 expression. TRIM29 is required for suppression of an increase in the adhesion activity of cells by TAp63α. These findings suggest that TRIM29 regulates the p63-mediated pathway and the behavior of cervical cancer cells. PMID:26071105

  8. Signaling pathways regulating Homer1a expression: implications for antidepressant therapy.

    PubMed

    Serchov, Tsvetan; Heumann, Rolf; van Calker, Dietrich; Biber, Knut

    2016-03-01

    Homer1a is upregulated by several different antidepressant measures, including non-pharmacological treatments, like sleep deprivation (SD) and electroconvulsive therapy (ECT) and antidepressant drugs, such as imipramine, fluoxetine and ketamine. Homer1a induction might thus be a crucial joint mechanism for antidepressant therapy in general. However, the upstream signaling pathways that regulate or induce Homer1a expression are still not well understood. The main focus of the present review is to offer an overview of the current knowledge about the potential role of Homer1a in depression and the signaling pathways responsible for Homer1a regulation. It is suggested here that a detailed characterization of the signaling mechanisms leading to Homer1a expression might provide novel therapeutic targets for antidepressant drug development. PMID:26641965

  9. Mitotic catenation is monitored and resolved by a PKCε-regulated pathway.

    PubMed

    Brownlow, Nicola; Pike, Tanya; Zicha, Daniel; Collinson, Lucy; Parker, Peter J

    2014-01-01

    Exit from mitosis is controlled by silencing of the spindle assembly checkpoint (SAC). It is important that preceding exit, all sister chromatid pairs are correctly bioriented, and that residual catenation is resolved, permitting complete sister chromatid separation in the ensuing anaphase. Here we determine that the metaphase response to catenation in mammalian cells operates through PKCε. The PKCε-controlled pathway regulates exit from the SAC only when mitotic cells are challenged by retained catenation and this delayed exit is characterized by BubR1-high and Mad2-low kinetochores. In addition, we show that this pathway is necessary to facilitate resolution of retained catenanes in mitosis. When delayed by catenation in mitosis, inhibition of PKCε results in premature entry into anaphase with PICH-positive strands and chromosome bridging. These findings demonstrate the importance of PKCε-mediated regulation in protection from loss of chromosome integrity in cells failing to resolve catenation in G2. PMID:25483024

  10. Regulation of Pol III Transcription by Nutrient and Stress Signaling Pathways

    PubMed Central

    Moir, Robyn D.; Willis, Ian M.

    2012-01-01

    Transcription by RNA polymerase III (pol III) is responsible for ~15% of total cellular transcription through the generation of small structured RNAs such as tRNA and 5S RNA. The coordinate synthesis of these molecules with ribosomal protein mRNAs and rRNA couples the production of ribosomes and their tRNA substrates and balances protein synthetic capacity with the growth requirements of the cell. Ribosome biogenesis in general and pol III transcription in particular is known to be regulated by nutrient availability, cell stress and cell cycle stage and is perturbed in pathological states. High throughput proteomic studies have catalogued modifications to pol III subunits, assembly, initiation and accessory factors but most of these modifications have yet to be linked to functional consequences. Here we review our current understanding of the major points of regulation in the pol III transcription apparatus, the targets of regulation and the signaling pathways known to regulate their function. PMID:23165150

  11. Distinct pathways of insulin-regulated versus diabetes-regulated gene expression: An in vivo analysis in MIRKO mice

    PubMed Central

    Yechoor, Vijay K.; Patti, Mary-Elizabeth; Ueki, Kohjiro; Laustsen, Palle G.; Saccone, Robert; Rauniyar, Ravi; Kahn, C. Ronald

    2004-01-01

    Diabetes mellitus is a complex metabolic disorder accompanied by alterations in cellular physiology, metabolism, and gene expression. These alterations can be primary (due to loss of direct insulin action) or secondary (due to the metabolic perturbations associated with the disease). To dissect and quantitate these two separate effects, we compared the skeletal muscle gene-expression profiles of muscle insulin receptor knockout (MIRKO) mice and their Lox controls in the basal, streptozotocin-induced diabetic, and insulin-treated diabetic states. Pure deficiency of insulin action as present in the MIRKO mouse results in regulation of 130 genes, with down-regulation of NSF (N-ethylmaleimide-sensitive fusion protein) and VAMP-2 (vesicle-associated membrane protein 2), stearoyl CoA desaturase 1, and cAMP-specific phosphodiesterase 4B, as well as up-regulation of some signaling-related genes, such as Akt2, and the fatty-acid transporter CD36. In diabetes, additional transcriptional mechanisms are activated, resulting in alterations in expression of ≈500 genes, including a highly coordinated down-regulation of genes of the mitochondrial electron-transport chain and one of the mammalian homologues of the histone deacetylase Sir2, which has been implicated in the link between nutrition and longevity. These distinct pathways of direct and indirect regulation of gene expression provide insights into the complex mechanisms of transcriptional control in diabetes and areas of potential therapeutic targeting. PMID:15546994

  12. Regulation of PHLDA1 Expression by JAK2-ERK1/2-STAT3 Signaling Pathway.

    PubMed

    Lyu, Ji Hyo; Huang, Bin; Park, Dae-Weon; Baek, Suk-Hwan

    2016-02-01

    Toll-like receptor 2 (TLR2)-mediated signaling cascades and gene regulation are mainly involved in diseases, such as immunity and inflammation. In this study, microarray analysis was performed using bone marrow-derived macrophages (BMDM) and Raw 264.7 cells to identify novel proteins involved in the TLR2-mediated cellular response. We found that pleckstrin homology-like domain family, member 1 (PHLDA1) is a novel gene up-regulated by TLR2 stimulation and determined the unique signaling pathway for its expression. Treatment with TLR2 agonist Pam3 CSK4 increased mRNA, protein, and fluorescence staining of PHLDA1. Induction of PHLDA1 by TLR2 stimulation disappeared from TLR2 KO mice-derived BMDM. Among janus kinase (JAK) family members, JAK2 was involved in TLR2-stimulated PHLDA1 expression. Signal transducer and activator of transcription 3 (STAT3) also participated in PHLDA1 expression downstream of the JAK2. Interestingly, ERK1/2 was an intermediate between JAK2 and STAT3. In silico analysis revealed the presence of highly conserved γ-activated sites within mouse PHLDA1 promoter and confirmed the JAK2-STAT3 pathway is important to Pam3 CSK4 -induced PHLDA1 transcription. These findings suggest that the JAK2-ERK1/2-STAT3 pathway is an important signaling pathway for PHLDA1 expression and that these proteins may play a critical role in eliciting TLR2-mediated immune and inflammatory response. PMID:26239656

  13. Regulation of Cell Wall Biogenesis in Saccharomyces cerevisiae: The Cell Wall Integrity Signaling Pathway

    PubMed Central

    Levin, David E.

    2011-01-01

    The yeast cell wall is a strong, but elastic, structure that is essential not only for the maintenance of cell shape and integrity, but also for progression through the cell cycle. During growth and morphogenesis, and in response to environmental challenges, the cell wall is remodeled in a highly regulated and polarized manner, a process that is principally under the control of the cell wall integrity (CWI) signaling pathway. This pathway transmits wall stress signals from the cell surface to the Rho1 GTPase, which mobilizes a physiologic response through a variety of effectors. Activation of CWI signaling regulates the production of various carbohydrate polymers of the cell wall, as well as their polarized delivery to the site of cell wall remodeling. This review article centers on CWI signaling in Saccharomyces cerevisiae through the cell cycle and in response to cell wall stress. The interface of this signaling pathway with other pathways that contribute to the maintenance of cell wall integrity is also discussed. PMID:22174182

  14. Signaling molecules and pathways regulating the fate of spermatogonial stem cells

    PubMed Central

    He, Zuping; Kokkinaki, Maria; Dym, Martin

    2009-01-01

    Spermatogenesis is the process that involves the division and differentiation of spermatogonial stem cells (SSCs) into mature spermatozoa. SSCs are a subpopulation of type A spermatogonia resting on the basement membrane in the mammalian testis. Self-renewal and differentiation of SSCs are the foundation of normal spermatogenesis, and thus a better understanding of molecular mechanisms and signaling pathways in the SSCs is of paramount importance for the regulation of spermatogenesis and may eventually lead to novel targets for male contraception as well as for gene therapy of male infertility and testicular cancer. Uncovering the molecular mechanisms is also of great interest to a better understanding of SSC aging and for developing novel therapeutic strategies for degenerative diseases in view of the recent work demonstrating the pluripotent potential of the SSC. Progress has recently been made in elucidating the signaling molecules and pathways that determine cell fate decisions of SSCs. In this review, we first address the morphological features, phenotypic characteristics, and the potential of SSCs. And then we focus on the recent advances in defining the key signaling molecules and crucial signaling pathways regulating self-renewal and differentiation of SSCs. The association of aberrant expression of signaling molecules and cascades with abnormal spermatogenesis and testicular cancer are also discussed. Finally we point out potential future directions to pursue in research on signaling pathways of SSCs. PMID:19263492

  15. ERK5 pathway regulates the phosphorylation of tumour suppressor hDlg during mitosis

    SciTech Connect

    Inesta-Vaquera, Francisco A.; Campbell, David G.; Arthur, J. Simon C.; Cuenda, Ana

    2010-08-13

    Research highlights: {yields} hDlg is phosphorylated during mitosis in multiple residues. {yields} Prospho-hDlg is excluded from the midbody during mitosis. {yields} hDlg is not phosphorylated by p38{gamma} or JNK1/2 during mitosis. {yields} ERK5 pathway mediates hDlg phosphorylation in mitosis. -- Abstract: Human disc-large (hDlg) is a scaffold protein critical for the maintenance of cell polarity and adhesion. hDlg is thought to be a tumour suppressor that regulates the cell cycle and proliferation. However, the mechanism and pathways involved in hDlg regulation during these processes is still unclear. Here we report that hDlg is phosphorylated during mitosis, and we establish the identity of at least three residues phosphorylated in hDlg; some are previously unreported. Phosphorylation affects hDlg localisation excluding it from the contact point between the two daughter cells. Our results reveal a previously unreported pathway for hDlg phosphorylation in mitosis and show that ERK5 pathway mediates hDlg cell cycle dependent phosphorylation. This is likely to have important implications in the correct timely mitotic entry and mitosis progression.

  16. Cdk9 T-loop Phosphorylation is Regulated by the Calcium Signaling Pathway

    PubMed Central

    Ramakrishnan, Rajesh; Rice, Andrew P.

    2011-01-01

    Eukaryotic RNA polymerase II transcriptional elongation is a tightly regulated process and is dependent upon positive transcription elongation factor-b (P-TEFb). The core P-TEFb complex is composed of Cdk9 and Cyclin T and is essential for the expression of most protein coding genes. Cdk9 kinase function is dependent upon phosphorylation of Thr186 in its T-loop. In this study, we examined kinases and signaling pathways that influence Cdk9 T-loop phosphorylation. Using an RNAi screen in HeLa cells, we found that Cdk9 T-loop phosphorylation is regulated by Calcium/Calmodulin- dependent kinase 1D (CaMK1D). Using small molecules inhibitors in HeLa cells and primary CD4+ T lymphocytes, we found that the Ca2+ signaling pathway is required for Cdk9 T-loop phosphorylation. Inhibition of Ca2+ signaling led to dephosphorylation of Thr186 on Cdk9. In reporter plasmid assays, inhibition of the Ca2+ signaling pathway repressed the PCNA promoter and HIV-1 Tat transactivation of the HIV-1 LTR, but not HTLV-1 Tax transactivation of the HTLV-1 LTR, suggesting that perturbation of the Ca2+ pathway and reduction of Cdk9 T-loop phosphorylation inhibits transcription units that have a rigorous requirement for P-TEFb function. PMID:21448926

  17. The PINK1-Parkin pathway is involved in the regulation of mitochondrial remodeling process

    SciTech Connect

    Park, Jeehye; Lee, Gina; Chung, Jongkyeong

    2009-01-16

    The two Parkinson's disease (PD) genes, PTEN-induced kinase 1 (PINK1) and parkin, are linked in a common pathway which affects mitochondrial integrity and function. However, it is still not known what this pathway does in the mitochondria. Therefore, we investigated its physiological function in Drosophila. Because Drosophila PINK1 and parkin mutants show changes in mitochondrial morphology in both indirect flight muscles and dopaminergic neurons, we here investigated whether the PINK1-Parkin pathway genetically interacts with the regulators of mitochondrial fusion and fission such as Drp1, which promotes mitochondrial fission, and Opa1 or Marf, which induces mitochondrial fusion. Surprisingly, DrosophilaPINK1 and parkin mutant phenotypes were markedly suppressed by overexpression of Drp1 or downregulation of Opa1 or Marf, indicating that the PINK1-Parkin pathway regulates mitochondrial remodeling process in the direction of promoting mitochondrial fission. Therefore, we strongly suggest that mitochondrial fusion and fission process could be a prominent therapeutic target for the treatment of PD.

  18. TRIM39 negatively regulates the NFκB-mediated signaling pathway through stabilization of Cactin.

    PubMed

    Suzuki, Masanobu; Watanabe, Masashi; Nakamaru, Yuji; Takagi, Dai; Takahashi, Hidehisa; Fukuda, Satoshi; Hatakeyama, Shigetsugu

    2016-03-01

    NFκB is one of the central regulators of cell survival, immunity, inflammation, carcinogenesis and organogenesis. The activation of NFκB is strictly regulated by several posttranslational modifications including phosphorylation, neddylation and ubiquitination. Several types of ubiquitination play important roles in multi-step regulations of the NFκB pathway. Some of the tripartite motif-containing (TRIM) proteins functioning as E3 ubiquitin ligases are known to regulate various biological processes such as inflammatory signaling pathways. One of the TRIM family proteins, TRIM39, for which the gene has single nucleotide polymorphisms, has been identified as one of the genetic factors in Behcet's disease. However, the role of TRIM39 in inflammatory signaling had not been fully elucidated. In this study, to elucidate the function of TRIM39 in inflammatory signaling, we performed yeast two-hybrid screening using TRIM39 as a bait and identified Cactin, which has been reported to inhibit NFκB- and TLR-mediated transcriptions. We show that TRIM39 stabilizes Cactin protein and that Cactin is upregulated after TNFα stimulation. TRIM39 knockdown also causes activation of the NFκB signal. These findings suggest that TRIM39 negatively regulates the NFκB signal in collaboration with Cactin induced by inflammatory stimulants such as TNFα. PMID:26363554

  19. Functional CRISPR screening identifies the ufmylation pathway as a regulator of SQSTM1/p62.

    PubMed

    DeJesus, Rowena; Moretti, Francesca; McAllister, Gregory; Wang, Zuncai; Bergman, Phil; Liu, Shanming; Frias, Elizabeth; Alford, John; Reece-Hoyes, John S; Lindeman, Alicia; Kelliher, Jennifer; Russ, Carsten; Knehr, Judith; Carbone, Walter; Beibel, Martin; Roma, Guglielmo; Ng, Aylwin; Tallarico, John A; Porter, Jeffery A; Xavier, Ramnik J; Mickanin, Craig; Murphy, Leon O; Hoffman, Gregory R; Nyfeler, Beat

    2016-01-01

    SQSTM1 is an adaptor protein that integrates multiple cellular signaling pathways and whose expression is tightly regulated at the transcriptional and post-translational level. Here, we describe a forward genetic screening paradigm exploiting CRISPR-mediated genome editing coupled to a cell selection step by FACS to identify regulators of SQSTM1. Through systematic comparison of pooled libraries, we show that CRISPR is superior to RNAi in identifying known SQSTM1 modulators. A genome-wide CRISPR screen exposed MTOR signalling and the entire macroautophagy machinery as key regulators of SQSTM1 and identified several novel modulators including HNRNPM, SLC39A14, SRRD, PGK1 and the ufmylation cascade. We show that ufmylation regulates SQSTM1 by eliciting a cell type-specific ER stress response which induces SQSTM1 expression and results in its accumulation in the cytosol. This study validates pooled CRISPR screening as a powerful method to map the repertoire of cellular pathways that regulate the fate of an individual target protein. PMID:27351204

  20. The Transcription Factor EB (TFEB) Regulates Osteoblast Differentiation Through ATF4/CHOP-Dependent Pathway.

    PubMed

    Yoneshima, Erika; Okamoto, Kuniaki; Sakai, Eiko; Nishishita, Kazuhisa; Yoshida, Noriaki; Tsukuba, Takayuki

    2016-06-01

    Osteoblasts are bone-forming cells that produce large amounts of collagen type I and various bone matrix proteins. Although osteoblast differentiation is highly regulated by various factors, it remains unknown whether lysosomes are directly involved in osteoblast differentiation. Here, we demonstrate the transcription factor EB (TFEB), a master regulator of lysosomal biogenesis, modulates osteoblast differentiation. The expression levels of TFEB as well as those of endosomal/lysosomal proteins were up-regulated during osteoblast differentiation using mouse osteoblastic MC3T3-E1 cells. By gene knockdown (KD) experiments with small interfering RNA (siRNA), TFEB depletion caused markedly reduced osteoblast differentiation as compared with the control cells. Conversely, overexpression (OE) of TFEB resulted in strikingly enhanced osteoblastogenesis compared to the control cells. By analysis of down-stream effector molecules, TFEB KD was found to cause marked up-regulation of activating transcription factor 4 (ATF4) and CCAAT/enhancer-binding protein homologous protein (CHOP), both of which are essential factors for osteoblastogenesis. In contrast, TFEB OE promoted osteoblast differentiation through reduced expression of ATF4 and CHOP without differentiation agents. Given the importance of ATF4 and CHOP in osteoblastogenesis, it is clear that the TFEB-regulated signaling pathway for osteoblast differentiation is involved in ATF4/CHOP-dependent signaling pathway. PMID:26519689

  1. Functional CRISPR screening identifies the ufmylation pathway as a regulator of SQSTM1/p62

    PubMed Central

    DeJesus, Rowena; Moretti, Francesca; McAllister, Gregory; Wang, Zuncai; Bergman, Phil; Liu, Shanming; Frias, Elizabeth; Alford, John; Reece-Hoyes, John S; Lindeman, Alicia; Kelliher, Jennifer; Russ, Carsten; Knehr, Judith; Carbone, Walter; Beibel, Martin; Roma, Guglielmo; Ng, Aylwin; Tallarico, John A; Porter, Jeffery A; Xavier, Ramnik J; Mickanin, Craig; Murphy, Leon O; Hoffman, Gregory R; Nyfeler, Beat

    2016-01-01

    SQSTM1 is an adaptor protein that integrates multiple cellular signaling pathways and whose expression is tightly regulated at the transcriptional and post-translational level. Here, we describe a forward genetic screening paradigm exploiting CRISPR-mediated genome editing coupled to a cell selection step by FACS to identify regulators of SQSTM1. Through systematic comparison of pooled libraries, we show that CRISPR is superior to RNAi in identifying known SQSTM1 modulators. A genome-wide CRISPR screen exposed MTOR signalling and the entire macroautophagy machinery as key regulators of SQSTM1 and identified several novel modulators including HNRNPM, SLC39A14, SRRD, PGK1 and the ufmylation cascade. We show that ufmylation regulates SQSTM1 by eliciting a cell type-specific ER stress response which induces SQSTM1 expression and results in its accumulation in the cytosol. This study validates pooled CRISPR screening as a powerful method to map the repertoire of cellular pathways that regulate the fate of an individual target protein. DOI: http://dx.doi.org/10.7554/eLife.17290.001 PMID:27351204

  2. Dual Control of Muscle Cell Survival by Distinct Growth Factor-Regulated Signaling Pathways

    PubMed Central

    Lawlor, Margaret A.; Feng, Xiuhong; Everding, Daniel R.; Sieger, Kerry; Stewart, Claire E. H.; Rotwein, Peter

    2000-01-01

    In addition to their ability to stimulate cell proliferation, polypeptide growth factors are able to maintain cell survival under conditions that otherwise lead to apoptotic death. Growth factors control cell viability through regulation of critical intracellular signal transduction pathways. We previously characterized C2 muscle cell lines that lacked endogenous expression of insulin-like growth factor II (IGF-II). These cells did not differentiate but underwent apoptotic death in low-serum differentiation medium. Death could be prevented by IGF analogues that activated the IGF-I receptor or by unrelated growth factors such as platelet-derived growth factor BB (PDGF-BB). Here we analyze the signaling pathways involved in growth factor-mediated myoblast survival. PDGF treatment caused sustained activation of extracellular-regulated kinases 1 and 2 (ERK1 and -2), while IGF-I only transiently induced these enzymes. Transient transfection of a constitutively active Mek1, a specific upstream activator of ERKs, maintained myoblast viability in the absence of growth factors, while inhibition of Mek1 by the drug UO126 blocked PDGF-mediated but not IGF-stimulated survival. Although both growth factors activated phosphatidylinositol 3-kinase (PI3-kinase) to similar extents, only IGF-I treatment led to sustained stimulation of its downstream kinase, Akt. Transient transfection of a constitutively active PI3-kinase or an inducible Akt promoted myoblast viability in the absence of growth factors, while inhibition of PI3-kinase activity by the drug LY294002 selectively blocked IGF- but not PDGF-mediated muscle cell survival. In aggregate, these observations demonstrate that distinct growth factor-regulated signaling pathways independently control myoblast survival. Since IGF action also stimulates muscle differentiation, these results suggest a means to regulate myogenesis through selective manipulation of different signal transduction pathways. PMID:10757809

  3. Regulation of the polyamine metabolic pathway in the endometrium of cows during early diestrus.

    PubMed

    Ramos, Roney dos Santos; Mesquita, Fernando Silveira; D'Alexandri, Fabio L; Gonella-Diaza, Angela Maria; Papa, Paula de Carvalho; Binelli, Mario

    2014-07-01

    The timing and magnitude of exposure to preovulatory estradiol followed by post-ovulatory progesterone (periovulatory endocrine milieu) in cattle modulate endometrial gene expression, histotroph composition, and conceptus development, but the mechanisms underlying this regulation remain unknown. Using an experimental model based on the modulation of follicle growth, this work aimed to evaluate if the polyamine metabolic pathway is regulated by the periovulatory endocrine milieu. Nelore cows were manipulated to ovulate small (n = 15) or large (n = 15) follicles, then the profiles of polyamines and their synthetic enzymes were compared between groups. Transcripts for the enzymes of this pathway, ornithine decarboxylase 1 (ODC1; the rate-limiting enzyme in polyamine biosynthesis) protein quantification, adenosylmethionine decarboxylase 1 (AMD1) protein immunolocalization, and concentrations of the different polyamines (putrescine, spermidine, and spermine) were respectively quantified by quantitative reverse-transcriptase PCR, immunoblotting, immunohistochemistry, and gas chromatography-mass spectrometry in both the endometrium and uterine flushing. No differences in gene and protein expression or concentration of polyamines were observed between groups. There were significant correlations between the relative abundance of ODC1 and spermidine/spermine N1-acetyltransferase 1 (SAT1) transcripts as well as between antizyme inhibitor 1 (AZIN1) and adenosylmethionine decarboxylase 1 (AMD1) transcripts. In conclusion, our results show that the polyamine metabolic pathway is present and functional, but not regulated by the periovulatory endocrine milieu in the bovine endometrium. PMID:24659573

  4. Mucolipin-3 Regulates Luminal Calcium, Acidification, and Membrane Fusion in the Endosomal Pathway*

    PubMed Central

    Lelouvier, Benjamin; Puertollano, Rosa

    2011-01-01

    Mucolipin-3 (MCOLN3) is a pH-regulated Ca2+ channel that localizes to the endosomal pathway. Gain-of-function mutation in MCOLN3 causes the varitint-waddler (Va) phenotype in mice, which is characterized by hearing loss, vestibular dysfunction, and coat color dilution. The Va phenotype results from a punctual mutation (A419P) in the pore region of MCOLN3 that locks the channel in an open conformation causing massive entry of Ca2+ inside cells and inducing cell death by apoptosis. Overexpression of wild-type MCOLN3 produces severe alterations of the endosomal pathway, including enlargement and clustering of endosomes, delayed EGF receptor degradation, and impaired autophagosome maturation, thus suggesting that MCOLN3 plays an important role in the regulation of endosomal function. To understand better the physiological role of MCOLN3, we inhibited MCOLN3 function by expression of a channel-dead dominant negative mutant (458DD/KK) or by knockdown of endogenous MCOLN3. Remarkably, we found that impairment of MCOLN3 activity caused a significant accumulation of luminal Ca2+ in endosomes. This accumulation led to severe defects in endosomal acidification as well as to increased endosomal fusion. Our findings reveal a prominent role for MCOLN3 in regulating Ca2+ homeostasis at the endosomal pathway and confirm the importance of luminal Ca2+ for proper acidification and membrane fusion. PMID:21245134

  5. Mechanisms of JAK/STAT pathway negative regulation by the short coreceptor Eye Transformer/Latran

    PubMed Central

    Fisher, Katherine H.; Stec, Wojciech; Brown, Stephen; Zeidler, Martin P.

    2016-01-01

    Transmembrane receptors interact with extracellular ligands to transduce intracellular signaling cascades, modulate target gene expression, and regulate processes such as proliferation, apoptosis, differentiation, and homeostasis. As a consequence, aberrant signaling events often underlie human disease. Whereas the vertebrate JAK/STAT signaling cascade is transduced via multiple receptor combinations, the Drosophila pathway has only one full-length signaling receptor, Domeless (Dome), and a single negatively acting receptor, Eye Transformer/Latran (Et/Lat). Here we investigate the molecular mechanisms underlying Et/Lat activity. We demonstrate that Et/Lat negatively regulates the JAK/STAT pathway activity and can bind to Dome, thus reducing Dome:Dome homodimerization by creating signaling-incompetent Dome:Et/Lat heterodimers. Surprisingly, we find that Et/Lat is able to bind to both JAK and STAT92E but, despite the presence of putative cytokine-binding motifs, does not detectably interact with pathway ligands. We find that Et/Lat is trafficked through the endocytic machinery for lysosomal degradation but at a much slower rate than Dome, a difference that may enhance its ability to sequester Dome into signaling-incompetent complexes. Our data offer new insights into the molecular mechanism and regulation of Et/Lat in Drosophila that may inform our understanding of how short receptors function in other organisms. PMID:26658615

  6. Mechanisms of JAK/STAT pathway negative regulation by the short coreceptor Eye Transformer/Latran.

    PubMed

    Fisher, Katherine H; Stec, Wojciech; Brown, Stephen; Zeidler, Martin P

    2016-02-01

    Transmembrane receptors interact with extracellular ligands to transduce intracellular signaling cascades, modulate target gene expression, and regulate processes such as proliferation, apoptosis, differentiation, and homeostasis. As a consequence, aberrant signaling events often underlie human disease. Whereas the vertebrate JAK/STAT signaling cascade is transduced via multiple receptor combinations, the Drosophila pathway has only one full-length signaling receptor, Domeless (Dome), and a single negatively acting receptor, Eye Transformer/Latran (Et/Lat). Here we investigate the molecular mechanisms underlying Et/Lat activity. We demonstrate that Et/Lat negatively regulates the JAK/STAT pathway activity and can bind to Dome, thus reducing Dome:Dome homodimerization by creating signaling-incompetent Dome:Et/Lat heterodimers. Surprisingly, we find that Et/Lat is able to bind to both JAK and STAT92E but, despite the presence of putative cytokine-binding motifs, does not detectably interact with pathway ligands. We find that Et/Lat is trafficked through the endocytic machinery for lysosomal degradation but at a much slower rate than Dome, a difference that may enhance its ability to sequester Dome into signaling-incompetent complexes. Our data offer new insights into the molecular mechanism and regulation of Et/Lat in Drosophila that may inform our understanding of how short receptors function in other organisms. PMID:26658615

  7. A GRHL3-regulated repair pathway suppresses immune-mediated epidermal hyperplasia

    PubMed Central

    Gordon, William M.; Zeller, Michael D.; Klein, Rachel H.; Swindell, William R.; Ho, Hsiang; Espetia, Francisco; Gudjonsson, Johann E.; Baldi, Pierre F.; Andersen, Bogi

    2014-01-01

    Dermal infiltration of T cells is an important step in the onset and progression of immune-mediated skin diseases such as psoriasis; however, it is not known whether epidermal factors play a primary role in the development of these diseases. Here, we determined that the prodifferentiation transcription factor grainyhead-like 3 (GRHL3), which is essential during epidermal development, is dispensable for adult skin homeostasis, but required for barrier repair after adult epidermal injury. Consistent with activation of a GRHL3-regulated repair pathway in psoriasis, we found that GRHL3 is upregulated in lesional skin and binds known epidermal differentiation gene targets. Using an imiquimod-induced model of immune-mediated epidermal hyperplasia, we found that mice lacking GRHL3 have an exacerbated epidermal damage response, greater sensitivity to disease induction, delayed resolution of epidermal lesions, and resistance to anti–IL-22 therapy compared with WT animals. ChIP-Seq and gene expression profiling of murine skin revealed that while GRHL3 regulates differentiation pathways both during development and during repair from immune-mediated damage, it targets distinct sets of genes in the 2 processes. In particular, GRHL3 suppressed a number of alarmin and other proinflammatory genes after immune injury. This study identifies a GRHL3-regulated epidermal barrier repair pathway that suppresses disease initiation and helps resolve existing lesions in immune-mediated epidermal hyperplasia. PMID:25347468

  8. Proinflammatory Cytokines Regulate Cementogenic Differentiation of Periodontal Ligament Cells by Wnt/Ca(2+) Signaling Pathway.

    PubMed

    Han, Pingping; Lloyd, Tain; Chen, Zetao; Xiao, Yin

    2016-05-01

    Periodontal inflammation can inhibit cell differentiation of periodontal ligament cells (PDLCs), resulting in decreased bone/cementum regeneration ability. The Wnt signaling pathway, including canonical Wnt/β-catenin signaling and noncanonical Wnt/Ca(2+) signaling, plays essential roles in cell proliferation and differentiation during tooth development. However, little is still known whether noncanonical Wnt/Ca(2+) signaling cascade could regulate cementogenic/osteogenic differentiation capability of PDLCs within an inflammatory environment. Therefore, in this study, human PDLCs (hPDLCs) and their cementogenic differentiation potential were investigated in the presence of cytokines. The data demonstrated that both cytokines interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) inhibited cell proliferation, relative alkaline phosphatase activity, bone/cementum-related gene/protein expression, and canonical Wnt pathway-related gene/protein expression in hPDLCs. Interestingly, both cytokines upregulated the noncanonical Wnt/Ca(2+) signaling-related gene and protein expression in hPDLCs. When the Wnt/Ca(2+) pathway was blocked by Ca(2+)/calmodulin-dependent protein kinase II inhibitor KN93, even in the presence of IL-6 and TNF-α, cementogenesis could be stimulated in hPDLCs. Our data indicate that the Wnt/Ca(2+) pathway plays an inhibitory role on PDLC cementogenic differentiation in inflammatory microenvironments. Therefore, targeting the Wnt/Ca(2+) pathway may provide a novel therapeutic approach to improve periodontal regeneration for periodontal diseases. PMID:27074616

  9. HIF-1α pathway: role, regulation and intervention for cancer therapy.

    PubMed

    Masoud, Georgina N; Li, Wei

    2015-09-01

    Hypoxia-inducible factor-1 (HIF-1) has been recognized as an important cancer drug target. Many recent studies have provided convincing evidences of strong correlation between elevated levels of HIF-1 and tumor metastasis, angiogenesis, poor patient prognosis as well as tumor resistance therapy. It was found that hypoxia (low O2 levels) is a common character in many types of solid tumors. As an adaptive response to hypoxic stress, hypoxic tumor cells activate several survival pathways to carry out their essential biological processes in different ways compared with normal cells. Recent advances in cancer biology at the cellular and molecular levels highlighted the HIF-1α pathway as a crucial survival pathway for which novel strategies of cancer therapy could be developed. However, targeting the HIF-1α pathway has been a challenging but promising progresses have been made in the past twenty years. This review summarizes the role and regulation of the HIF-1α in cancer, and recent therapeutic approaches targeting this important pathway. PMID:26579469

  10. Transcriptional regulators in the Hippo signaling pathway control organ growth in Xenopus tadpole tail regeneration.

    PubMed

    Hayashi, Shinichi; Ochi, Haruki; Ogino, Hajime; Kawasumi, Aiko; Kamei, Yasuhiro; Tamura, Koji; Yokoyama, Hitoshi

    2014-12-01

    The size and shape of tissues are tightly controlled by synchronized processes among cells and tissues to produce an integrated organ. The Hippo signaling pathway controls both cell proliferation and apoptosis by dual signal-transduction states regulated through a repressive kinase cascade. Yap1 and Tead, transcriptional regulators that act downstream of the Hippo signaling kinase cascade, have essential roles in regulating cell proliferation. In amphibian limb or tail regeneration, the local tissue outgrowth terminates when the correct size is reached, suggesting that organ size is strictly controlled during epimorphic organ-level regeneration. We recently demonstrated that Yap1 is required for the regeneration of Xenopus tadpole limb buds (Hayashi et al., 2014, Dev. Biol. 388, 57-67), but the molecular link between the Hippo pathway and organ size control in vertebrate epimorphic regeneration is not fully understood. To examine the requirement of Hippo pathway transcriptional regulators in epimorphic regeneration, including organ size control, we inhibited these regulators during Xenopus tadpole tail regeneration by overexpressing a dominant-negative form of Yap (dnYap) or Tead4 (dnTead4) under a heat-shock promoter in transgenic animal lines. Each inhibition resulted in regeneration defects accompanied by reduced cell mitosis and increased apoptosis. Single-cell gene manipulation experiments indicated that Tead4 cell-autonomously regulates the survival of neural progenitor cells in the regenerating tail. In amphibians, amputation at the proximal level of the tail (deep amputation) results in faster regeneration than that at the distal level (shallow amputation), to restore the original-sized tail with similar timing. However, dnTead4 overexpression abolished the position-dependent differential growth rate of tail regeneration. These results suggest that the transcriptional regulators in the Hippo pathway, Tead4 and Yap1, are required for general vertebrate

  11. The regulation of pulmonary inflammation by the hypoxia-inducible factor-hydroxylase oxygen-sensing pathway.

    PubMed

    Whyte, Moira K B; Walmsley, Sarah R

    2014-12-01

    Although the hypoxia-inducible factor (HIF)-hydroxylase oxygen-sensing pathway has been extensively reviewed in the context of cellular responses to hypoxia and cancer biology, its importance in regulating innate immune biology is less well described. In this review, we focus on the role of the HIF-hydroxylase pathway in regulating myeloid cell responses and its relevance to inflammatory lung disease. The more specific roles of individual HIF/ prolyl hydroxylase pathway members in vivo are discussed in the context of lineage-specific rodent models of inflammation, with final reference made to the therapeutic challenges of targeting the HIF/hydroxylase pathway in immune cells. PMID:25525731

  12. Regulation of Autophagic Activation by Rta of Epstein-Barr Virus via the Extracellular Signal-Regulated Kinase Pathway

    PubMed Central

    Chen, Lee-Wen; Wang, Wen-Hung; Chang, Pey-Jium; Chiu, Ya-Fang; Hung, Chen-Chia; Lin, Ying-Ju; Liou, Jieh-Yuan; Tsai, Wan-Ju; Hung, Chia-Ling

    2014-01-01

    ABSTRACT Autophagy is an intracellular degradation pathway that provides a host defense mechanism against intracellular pathogens. However, many viruses exploit this mechanism to promote their replication. This study shows that lytic induction of Epstein-Barr virus (EBV) increases the membrane-bound form of LC3 (LC3-II) and LC3-containing punctate structures in EBV-positive cells. Transfecting 293T cells with a plasmid that expresses Rta also induces autophagy, revealing that Rta is responsible for autophagic activation. The activation involves Atg5, a key component of autophagy, but not the mTOR pathway. The expression of Rta also activates the transcription of the genes that participate in the formation of autophagosomes, including LC3A, LC3B, and ATG9B genes, as well as those that are involved in the regulation of autophagy, including the genes TNF, IRGM, and TRAIL. Additionally, treatment with U0126 inhibits the Rta-induced autophagy and the expression of autophagy genes, indicating that the autophagic activation is caused by the activation of extracellular signal-regulated kinase (ERK) signaling by Rta. Finally, the inhibition of autophagic activity by an autophagy inhibitor, 3-methyladenine, or Atg5 small interfering RNA, reduces the expression of EBV lytic proteins and the production of viral particles, revealing that autophagy is critical to EBV lytic progression. This investigation reveals how an EBV-encoded transcription factor promotes autophagy to affect viral lytic development. PMID:25122800

  13. Feedback inhibition of deoxy-D-xylulose-5-phosphate synthase regulates the methylerythritol 4-phosphate pathway.

    PubMed

    Banerjee, Aparajita; Wu, Yan; Banerjee, Rahul; Li, Yue; Yan, Honggao; Sharkey, Thomas D

    2013-06-01

    The 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway leads to the biosynthesis of isopentenyl diphosphate (IDP) and dimethylallyl diphosphate (DMADP), the precursors for isoprene and higher isoprenoids. Isoprene has significant effects on atmospheric chemistry, whereas other isoprenoids have diverse roles ranging from various biological processes to applications in commercial uses. Understanding the metabolic regulation of the MEP pathway is important considering the numerous applications of this pathway. The 1-deoxy-D-xylulose-5-phosphate synthase (DXS) enzyme was cloned from Populus trichocarpa, and the recombinant protein (PtDXS) was purified from Escherichia coli. The steady-state kinetic parameters were measured by a coupled enzyme assay. An LC-MS/MS-based assay involving the direct quantification of the end product of the enzymatic reaction, 1-deoxy-D-xylulose 5-phosphate (DXP), was developed. The effect of different metabolites of the MEP pathway on PtDXS activity was tested. PtDXS was inhibited by IDP and DMADP. Both of these metabolites compete with thiamine pyrophosphate for binding with the enzyme. An atomic structural model of PtDXS in complex with thiamine pyrophosphate and Mg(2+) was built by homology modeling and refined by molecular dynamics simulations. The refined structure was used to model the binding of IDP and DMADP and indicated that IDP and DMADP might bind with the enzyme in a manner very similar to the binding of thiamine pyrophosphate. The feedback inhibition of PtDXS by IDP and DMADP constitutes an important mechanism of metabolic regulation of the MEP pathway and indicates that thiamine pyrophosphate-dependent enzymes may often be affected by IDP and DMADP. PMID:23612965

  14. Merlin inhibits growth hormone-regulated Raf-ERKs pathways by binding to Grb2 protein

    SciTech Connect

    Lim, Jung Yeon; Kim, Hongtae; Jeun, Sin-Soo . E-mail: ssjeun@catholic.ac.kr; Kang, Seok-Gu; Lee, Kyung-Jin

    2006-02-24

    Numerous studies have suggested that the NF2 protein merlin is involved in the regulation of abnormal cell growth and proliferation. In this study, to better understand the merlin's mechanisms that contribute to the inhibition of tumorigenesis, we examined the potential action of merlin on the cell proliferative signaling pathways in response to growth hormone (GH). Merlin effectively attenuated the GH-induced serum response element (SRE) and Elk-1-mediated transcriptional activation, as well as the endogenous SRE-regulated gene c-fos expression in NIH3T3 cells. In addition, merlin prevented the Raf-1 complex activation process, which resulted in the suppression of MAP kinase/ERK, extracellular signal-regulated kinase (ERKs), and Elk-1 phosphorylation, which are the downstream signals of Raf-1. Moreover, it was shown that merlin interacted with endogenous growth factor receptor bound 2 (Grb2) protein and inhibited its expression. These results suggest that merlin contributes, via its protein-to-protein interaction with Grb2 and consequent inhibition of the MAPK pathways, to the regulation of the abnormal cell proliferation, and this provides a further mechanism underlying the tumor suppressor function of merlin.

  15. Deubiquitylating enzyme USP9x regulates hippo pathway activity by controlling angiomotin protein turnover

    PubMed Central

    Thanh Nguyen, Hung; Andrejeva, Diana; Gupta, Rajat; Choudhary, Chunaram; Hong, Xin; Eichhorn, Pieter J A; Loya, Anand C; Cohen, Stephen M

    2016-01-01

    The Hippo pathway has been identified as a key barrier for tumorigenesis, acting through downregulation of YAP/TAZ activity. Elevated YAP/TAZ activity has been documented in many human cancers. Ubiquitylation has been shown to play a key role in regulating YAP/TAZ activity through downregulation of a number of Hippo pathway components. Several ubiquitin ligase complexes have been implicated in this process, however, little is known about the deubiquitylating enzymes that counteract these activities to regulate YAP/TAZ. Here we identify the deubiquitylating enzyme USP9x as a regulator of YAP/TAZ activity. We demonstrate that USPx regulates ubiquitin-mediated turnover of the YAP inhibitor, Angiomotin. USP9x acts to deubiquitylate Angiomotin at lysine 496, resulting in stabilization of Angiomotin and lower YAP/TAZ activity. USP9x mRNA levels were reduced in several cancers. Clinically, USP9x mRNA levels were reduced in several cancers with low USPx expression correlating with poor prognosis in renal clear cell carcinoma. Our data indicate that USP9x may be a useful biomarker for renal clear cell carcinoma. PMID:27462448

  16. Interferon-γ regulates intestinal epithelial homeostasis through converging β-catenin signaling pathways

    PubMed Central

    Nava, Porfirio; Koch, Stefan; Laukoetter, Mike G; Lee, Winston Y; Kolegraff, Keli; Capaldo, Christopher T; Beeman, Neal; Addis, Caroline; Gerner-Smidt, Kirsten; Neumaier, Irmgard; Skerra, Arne; Li, Linheng; Parkos, Charles A; Nusrat, Asma

    2010-01-01

    SUMMARY Inflammatory cytokines have been proposed to regulate epithelial homeostasis during intestinal inflammation. We report here that interferon-γ (IFN-γ) regulates the crucial homeostatic functions of cell proliferation and apoptosis through serine-threonine protein kinase AKT-β-catenin and Wingless-Int (Wnt)-β-catenin signaling pathways. Short-term exposure of intestinal epithelial cells to IFN-γ resulted in activation of β-catenin through AKT, followed by induction of the secreted Wnt inhibitor Dkk1. Consequently, we observed an increase in Dkk1-mediated apoptosis upon extended IFN-γ treatment, and reduced proliferation through depletion of the Wnt co-receptor LRP6. These effects were enhanced by tumor necrosis factor-α (TNF)-α, suggesting synergism between the two cytokines. Consistent with these results, colitis in vivo was associated with decreased β-catenin-T-cell factor (TCF) signaling, loss of plasma membrane-associated LRP6, and reduced epithelial cell proliferation. Proliferation was partially restored in IFN-γ - deficient mice. Thus, we propose that IFN-γ regulates intestinal epithelial homeostasis by sequential regulation of converging β-catenin signaling pathways. PMID:20303298

  17. Gonad differentiation in zebrafish is regulated by the canonical Wnt signaling pathway.

    PubMed

    Sreenivasan, Rajini; Jiang, Junhui; Wang, Xingang; Bártfai, Richárd; Kwan, Hsiao Yuen; Christoffels, Alan; Orbán, László

    2014-02-01

    Zebrafish males undergo a "juvenile ovary-to-testis" gonadal transformation process. Several genes, including nuclear receptor subfamily 5, group A (nr5a) and anti-Müllerian hormone (amh), and pathways such as Tp53-mediated germ-cell apoptosis have been implicated in zebrafish testis formation. However, our knowledge of the regulation of this complex process is incomplete, and much remains to be investigated about the molecular pathways and network of genes that control it. Using a microarray-based analysis of transforming zebrafish male gonads, we demonstrated that their transcriptomes undergo transition from an ovary-like pattern to an ovotestis to a testis-like profile. Microarray results also validated the previous histological and immunohistochemical observation that there is high variation in the duration and extent of commitment to the juvenile ovary phase among individuals. Interestingly, global gene expression profiling of diverging zebrafish juvenile ovaries and transforming ovotestes revealed that some members of the canonical Wnt/beta-catenin signaling pathway were differentially expressed between these two phases. To investigate whether Wnt/beta-catenin signaling plays a role in zebrafish gonad differentiation, we used the Tg (hsp70l:dkk1b-GFP)w32 line to inhibit Wnt/beta-catenin signaling during gonad differentiation. Activation of dkk1b-GFP expression by heat shock resulted in an increased proportion of males and corresponding decrease in gonadal aromatase gene (cyp19a1a) expression. The Wnt target gene, lymphocyte enhancer binding factor 1 (lef1), was also down-regulated in the process. Together, these results provide the first functional evidence that, similarly to mammals, Wnt/beta-catenin signaling is a "pro-female" pathway that regulates gonad differentiation in zebrafish. PMID:24174574

  18. Kaempferol regulates OPN-CD44 pathway to inhibit the atherogenesis of apolipoprotein E deficient mice

    SciTech Connect

    Xiao, Hong-Bo; Lu, Xiang-Yang; Sun, Zhi-Liang; Zhang, Heng-Bo

    2011-12-15

    Recent studies show that osteopontin (OPN) and its receptor cluster of differentiation 44 (CD44) are two pro-inflammatory cytokines contributing to the development of atherosclerosis. The objective of this study was to explore the inhibitory effect of kaempferol, a naturally occurring flavonoid compound, on atherogenesis and the mechanisms involved. The experiments were performed in aorta and plasma from C57BL/6J control and apolipoprotein E-deficient (ApoE{sup -/-}) mice treated or not with kaempferol (50 or 100 mg/kg, intragastrically) for 4 weeks. Kaempferol treatment decreased atherosclerotic lesion area, improved endothelium-dependent vasorelaxation, and increased the maximal relaxation value concomitantly with decrease in the half-maximum effective concentration, plasma OPN level, aortic OPN expression, and aortic CD44 expression in ApoE{sup -/-} mice. In addition, treatment with kaempferol also significantly decreased reactive oxygen species production in mice aorta. The present results suggest that kaempferol regulates OPN-CD44 pathway to inhibit the atherogenesis of ApoE{sup -/-} mice. -- Graphical abstract: Kaempferol regulates OPN-CD44 pathway to inhibit the atherogenesis of ApoE{sup -/-} mice. Highlights: Black-Right-Pointing-Pointer OPN-CD44 pathway plays a critical role in the development of atherosclerosis. Black-Right-Pointing-Pointer We examine lesion area, OPN and CD44 changes after kaempferol treatment. Black-Right-Pointing-Pointer Kaempferol treatment decreased atherosclerotic lesion area in ApoE{sup -/-} mice. Black-Right-Pointing-Pointer Kaempferol treatment decreased aortic OPN and CD44 expressions in ApoE{sup -/-} mice. Black-Right-Pointing-Pointer Kaempferol regulates OPN-CD44 pathway to inhibit the atherogenesis.

  19. PPARs in Regulation of Paraoxonases: Control of Oxidative Stress and Inflammation Pathways

    PubMed Central

    Camps, Jordi; García-Heredia, Anabel; Rull, Anna; Alonso-Villaverde, Carlos; Aragonès, Gerard; Beltrán-Debón, Raúl; Rodríguez-Gallego, Esther; Joven, Jorge

    2012-01-01

    The paraoxonase (PON) group of enzymes, composed of PON1, PON2, and PON3, play an important role in decreasing oxidative stress by degrading lipid peroxides. PON1 synthesis is upregulated by PPAR. Several pharmacological compounds (acting as antioxidants and, hence, atheroprotective) stimulate both PPAR activity and PON1 expression. Recent evidence suggests that PON1 and the monocyte chemoattractant protein-1 (MCP-1) are involved in coordinating the inflammatory response in damaged tissues; PPAR may be central in the regulation of these biochemical pathways. This article reviews the state of knowledge on PON1 biochemistry and function, the influence of genetic variation, and the regulation of PON1 expression by pharmaceutical compounds that increase PPAR activity. We also describe recent lines of evidence suggesting links between PON1 and MCP-1 and how their production may be regulated by PPAR. PMID:22315585

  20. Ankyrin-based Cellular Pathways for Cardiac Ion Channel and Transporter Targeting and Regulation

    PubMed Central

    Cunha, Shane R.; Mohler, Peter J.

    2010-01-01

    The coordinate activities of ion channels and transporters regulate myocyte membrane excitability and normal cardiac function. Dysfunction in cardiac ion channel and transporter function may result in cardiac arrhythmias and sudden cardiac death. While the past fifteen years have linked defects in ion channel biophysical properties with human disease, more recent findings illustrate that ion channel and transporter localization within cardiomyocytes is equally critical for normal membrane excitability and tissue function. Ankyrins are a family of multifunctional adapter proteins required for the expression, membrane localization, and regulation of select cardiac ion channels and transporters. Notably, loss of ankyrin expression in mice, and ankyrin loss-of-function in humans is now associated with defects in myocyte excitability and cardiac physiology. Here, we provide an overview of the roles of ankyrin polypeptides in cardiac physiology, as well as review other recently identified pathways required for the membrane expression and regulation of key cardiac ion channels and transporters. PMID:20934528

  1. Opposite phenotypes of cancer and aging arise from alternative regulation of common signaling pathways.

    PubMed

    Ukraintseva, Svetlana V; Yashin, Anatoly I

    2003-12-01

    Phenotypic features of malignant and senescent cells are in many instances opposite. Cancer cells do not "age"; their metabolic, proliferative, and growth characteristics are opposite to those observed with cellular aging (both replicative and functional). In many such characteristics cancer cells resemble embryonic cells. One can say that cancer manifests itself as a local, uncontrolled "rejuvenation" in an organism. Available evidence from human and animal studies suggests that the opposite phenotypic features of aging and cancer arise from the opposite regulation of genes participating in apoptosis/growth arrest or growth signal transduction pathways in cells. This fact may be applicable in the development of new anti-aging treatments. Genes that are contrarily regulated in cancer and aging cells (e.g., proto-oncogenes or tumor suppressors) could be candidate targets for anti-aging interventions. Their "cancer-like" regulation, if strictly controlled, might help to rejuvenate the human organism. PMID:15033776

  2. Comprehensive profiling analysis of actively resorbing osteoclasts identifies critical signaling pathways regulated by bone substrate

    PubMed Central

    Purdue, P. Edward; Crotti, Tania N.; Shen, Zhenxin; Swantek, Jennifer; Li, Jun; Hill, Jonathan; Hanidu, Adedayo; Dimock, Janice; Nabozny, Gerald; Goldring, Steven R.; McHugh, Kevin P.

    2014-01-01

    As the only cells capable of efficiently resorbing bone, osteoclasts are central mediators of both normal bone remodeling and pathologies associates with excessive bone resorption. However, despite the clear evidence of interplay between osteoclasts and the bone surface in vivo, the role of the bone substrate in regulating osteoclast differentiation and activation at a molecular level has not been fully defined. Here, we present the first comprehensive expression profiles of osteoclasts differentiated on authentic resorbable bone substrates. This analysis has identified numerous critical pathways coordinately regulated by osteoclastogenic cytokines and bone substrate, including the transition from proliferation to differentiation, and sphingosine-1-phosphate signaling. Whilst, as expected, much of this program is dependent upon integrin beta 3, the pre-eminent mediator of osteoclast-bone interaction, a surprisingly significant portion of the bone substrate regulated expression signature is independent of this receptor. Together, these findings identify an important hitherto underappreciated role for bone substrate in osteoclastogenesis. PMID:25534583

  3. Regulatory architecture determines optimal regulation of gene expression in metabolic pathways

    PubMed Central

    Chubukov, Victor; Zuleta, Ignacio A.; Li, Hao

    2012-01-01

    In response to environmental changes, the connections (“arrows”) in gene regulatory networks determine which genes modulate their expression, but the quantitative parameters of the network (“the numbers on the arrows”) are equally important in determining the resulting phenotype. What are the objectives and constraints by which evolution determines these parameters? We explore these issues by analyzing gene expression changes in a number of yeast metabolic pathways in response to nutrient depletion. We find that a striking pattern emerges that couples the regulatory architecture of the pathway to the gene expression response. In particular, we find that pathways controlled by the intermediate metabolite activation (IMA) architecture, in which an intermediate metabolite activates transcription of pathway genes, exhibit the following response: the enzyme immediately downstream of the regulatory metabolite is under the strongest transcriptional control, whereas the induction of the enzymes upstream of the regulatory intermediate is relatively weak. This pattern of responses is absent in pathways not controlled by an IMA architecture. The observation can be explained by the constraint imposed by the fundamental feedback structure of the network, which places downstream enzymes under a negative feedback loop and upstream ones under a positive feedback loop. This general design principle for transcriptional control of a metabolic pathway can be derived from a simple cost/benefit model of gene expression, in which the observed pattern is an optimal solution. Our results suggest that the parameters regulating metabolic enzyme expression are optimized by evolution, under the strong constraint of the underlying regulatory architecture. PMID:22416120

  4. Regulation of multiple angiogenic pathways by Dll4 and Notch in human umbilical vein endothelial cells.

    PubMed

    Harrington, Laura S; Sainson, Richard C A; Williams, Cassin Kimmel; Taylor, Jennifer M; Shi, Wen; Li, Ji-Liang; Harris, Adrian L

    2008-03-01

    The Notch ligand, Dll4, is essential for angiogenesis during embryonic vascular development and is involved in tumour angiogenesis. Several recent publications demonstrated that blockade of Dll4 signalling inhibits tumour growth, suggesting that it may constitute a good candidate for anti-cancer therapy. In order to understand the role of Dll4 at the cellular level, we performed an analysis of Dll4-regulated genes in HUVECs. The genes identified included several angiogenic signalling pathways, such as VEGF, FGF and HGF. In particular we identified downregulation (VEGFR2, placenta growth factor PlGF) of VEGF pathway components resulting in the overall effect of limiting the response of HUVEC to VEGF. However extensive upregulation of VEGFR1 was observed allowing continued response to its ligand PlGF but the soluble form of the VEGFR1, sVEGFR1 was also upregulated. PlGF enhanced tubulogenesis of HUVEC suggesting that downregulation of PlGF and upregulation of VEGFR1 including sVEGFR1 are important mechanisms by which Dll4 attenuates PlGF and VEGF signalling. Dll4-stimulated HUVECs had impaired ERK activation in response to VEGF and HGF indicating that Dll4 signalling negatively regulates these pathways. Dll4 expression reduced vessel sprout length in a 3D tubulogenesis assay confirming that Dll4 signalling inhibits angiogenesis. Altogether, our data suggest that Dll4 expression acts as a switch from the proliferative phase of angiogenesis to the maturation and stabilisation phase by blocking endothelial cell proliferation and allowing induction of a more mature, differentiated phenotype. The regulation of sVEGFR1 provides a novel mechanism for Dll4 signalling to regulate cells at distance, not just in adjacent cells. PMID:17692341

  5. Universality and diversity in the signal transduction pathway that regulates seasonal reproduction in vertebrates

    PubMed Central

    Nakane, Yusuke; Yoshimura, Takashi

    2014-01-01

    Most vertebrates living outside the tropical zone show robust physiological responses in response to seasonal changes in photoperiod, such as seasonal reproduction, molt, and migration. The highly sophisticated photoperiodic mechanism in Japanese quail has been used to uncover the mechanism of seasonal reproduction. Molecular analysis of quail mediobasal hypothalamus (MBH) revealed that local thyroid hormone activation within the MBH plays a critical role in the photoperiodic response of gonads. This activation is accomplished by two gene switches: thyroid hormone-activating (DIO2) and thyroid hormone-inactivating enzymes (DIO3). Functional genomics studies have shown that long-day induced thyroid-stimulating hormone (TSH) in the pars tuberalis (PT) of the pituitary gland regulates DIO2/3 switching. In birds, light information received directly by deep brain photoreceptors regulates PT TSH. Recent studies demonstrated that Opsin 5-positive cerebrospinal fluid (CSF)-contacting neurons are deep brain photoreceptors that regulate avian seasonal reproduction. Although the involvement of TSH and DIO2/3 in seasonal reproduction has been confirmed in various mammals, the light input pathway that regulates PT TSH in mammals differs from that of birds. In mammals, the eye is the only photoreceptor organ and light information received by the eye is transmitted to the pineal gland through the circadian pacemaker, the suprachiasmatic nucleus. Nocturnal melatonin secretion from the pineal gland indicates the length of night and regulates the PT TSH. In fish, the regulatory machinery for seasonal reproduction, from light input to neuroendocrine output, has been recently demonstrated in the coronet cells of the saccus vasculosus (SV). The SV is unique to fish and coronet cells are CSF-contacting neurons. Here, we discuss the universality and diversity of signal transduction pathways that regulate vertebrate seasonal reproduction. PMID:24959116

  6. Molecular Pathways Regulating Macrovascular Pathology and Vascular Smooth Muscle Cells Phenotype in Type 2 Diabetes

    PubMed Central

    Casella, Sara; Bielli, Alessandra; Mauriello, Alessandro; Orlandi, Augusto

    2015-01-01

    Type 2 diabetes mellitus (T2DM) is a disease reaching a pandemic proportion in developed countries and a major risk factor for almost all cardiovascular diseases and their adverse clinical manifestations. T2DM leads to several macrovascular and microvascular alterations that influence the progression of cardiovascular diseases. Vascular smooth muscle cells (VSMCs) are fundamental players in macrovascular alterations of T2DM patients. VSMCs display phenotypic and functional alterations that reflect an altered intracellular biomolecular scenario of great vessels of T2DM patients. Hyperglycemia itself and through intraparietal accumulation of advanced glycation-end products (AGEs) activate different pathways, in particular nuclear factor-κB and MAPKs, while insulin and insulin growth-factor receptors (IGFR) are implicated in the activation of Akt and extracellular-signal-regulated kinases (ERK) 1/2. Nuclear factor-κB is also responsible of increased susceptibility of VSMCs to pro-apoptotic stimuli. Down-regulation of insulin growth-factor 1 receptors (IGFR-1R) activity in diabetic vessels also influences negatively miR-133a levels, so increasing apoptotic susceptibility of VSMCs. Alterations of those bimolecular pathways and related genes associate to the prevalence of a synthetic phenotype of VSMCs induces extracellular matrix alterations of great vessels. A better knowledge of those biomolecular pathways and related genes in VSMCs will help to understand the mechanisms leading to macrovascular alterations in T2DM patients and to suggest new targeted therapies. PMID:26473856

  7. Dopamine is a key regulator in the signalling pathway underlying predator-induced defences in Daphnia.

    PubMed

    Weiss, Linda C; Leese, Florian; Laforsch, Christian; Tollrian, Ralph

    2015-10-01

    The waterflea Daphnia is a model to investigate the genetic basis of phenotypic plasticity resulting from one differentially expressed genome. Daphnia develops adaptive phenotypes (e.g. morphological defences) thwarting predators, based on chemical predator cue perception. To understand the genomic basis of phenotypic plasticity, the description of the precedent cellular and neuronal mechanisms is fundamental. However, key regulators remain unknown. All neuronal and endocrine stimulants were able to modulate but not induce defences, indicating a pathway of interlinked steps. A candidate able to link neuronal with endocrine responses is the multi-functional amine dopamine. We here tested its involvement in trait formation in Daphnia pulex and Daphnia longicephala using an induction assay composed of predator cues combined with dopaminergic and cholinergic stimulants. The mere application of both stimulants was sufficient to induce morphological defences. We determined dopamine localization in cells found in close association with the defensive trait. These cells serve as centres controlling divergent morphologies. As a mitogen and sclerotization agent, we anticipate that dopamine is involved in proliferation and structural formation of morphological defences. Furthermore, dopamine pathways appear to be interconnected with endocrine pathways, and control juvenile hormone and ecdysone levels. In conclusion, dopamine is suggested as a key regulator of phenotypic plasticity. PMID:26423840

  8. Regulation of the PI3K pathway through a p85α monomer–homodimer equilibrium

    PubMed Central

    Cheung, Lydia WT; Walkiewicz, Katarzyna W; Besong, Tabot MD; Guo, Huifang; Hawke, David H; Arold, Stefan T; Mills, Gordon B

    2015-01-01

    The canonical action of the p85α regulatory subunit of phosphatidylinositol 3-kinase (PI3K) is to associate with the p110α catalytic subunit to allow stimuli-dependent activation of the PI3K pathway. We elucidate a p110α-independent role of homodimerized p85α in the positive regulation of PTEN stability and activity. p110α-free p85α homodimerizes via two intermolecular interactions (SH3:proline-rich region and BH:BH) to selectively bind unphosphorylated activated PTEN. As a consequence, homodimeric but not monomeric p85α suppresses the PI3K pathway by protecting PTEN from E3 ligase WWP2-mediated proteasomal degradation. Further, the p85α homodimer enhances the lipid phosphatase activity and membrane association of PTEN. Strikingly, we identified cancer patient-derived oncogenic p85α mutations that target the homodimerization or PTEN interaction surface. Collectively, our data suggest the equilibrium of p85α monomer–dimers regulates the PI3K pathway and disrupting this equilibrium could lead to disease development. DOI: http://dx.doi.org/10.7554/eLife.06866.001 PMID:26222500

  9. MAN3 gene regulates cadmium tolerance through the glutathione-dependent pathway in Arabidopsis thaliana.

    PubMed

    Chen, Jian; Yang, Libo; Gu, Ju; Bai, Xiaoya; Ren, Yongbin; Fan, Tingting; Han, Yi; Jiang, Li; Xiao, Fangming; Liu, Yongsheng; Cao, Shuqing

    2015-01-01

    Pollution of soil by the heavy metal cadmium (Cd) is a global environmental problem. The glutathione (GSH)-dependent phytochelatin (PC) synthesis pathway is one of the most important mechanisms contributing to Cd accumulation and tolerance. However, the regulation of this pathway is poorly understood. Here, we identified an Arabidopsis thaliana cadmium-tolerant dominant mutant xcd1-D (XVE system-induced cadmium-tolerance 1) and cloned XCD1 gene (previously called MAN3), which encodes an endo-β-mannanase. Overexpression of MAN3 led to enhanced Cd accumulation and tolerance, whereas loss-of-function of MAN3 resulted in decreased Cd accumulation and tolerance. In the presence of estradiol, enhanced Cd accumulation and tolerance in xcd1-D was associated with GSH-dependent, Cd-activated synthesis of PCs, which was correlated with coordinated activation of gene expression. Cd stress-induced expression of MAN3 and the consequently increased mannanase activity, led to increased mannose content in cell walls. Moreover, mannose treatment not only rescued the Cd-sensitive phenotype of the xcd1-2 mutant, but also improved the Cd tolerance of wild-type plants. Significantly, this mannose-mediated Cd accumulation and tolerance is dependent on GSH-dependent PC concentrations via coordinated control of expression of genes involved in PC synthesis. Our results suggest that MAN3 regulates the GSH-dependent PC synthesis pathway that contributes to Cd accumulation and tolerance in A. thaliana by coordinated control of gene expression. PMID:25329733

  10. Intersectin-1s regulates the mitochondrial apoptotic pathway in endothelial cells.

    PubMed

    Predescu, Sanda A; Predescu, Dan N; Knezevic, Ivana; Klein, Irene K; Malik, Asrar B

    2007-06-01

    Intersectins (ITSNs) are multidomain adaptor proteins implicated in endocytosis, regulation of actin polymerization, and Ras/MAPK signaling. We have previously shown that ITSN-1s is required for caveolae fission and internalization in endothelial cells (ECs). In the present study, using small interfering RNA to knock down ITSN-1s protein expression, we demonstrate a novel role of ITSN-1s as a key antiapoptotic protein. Knockdown of ITSN-1s in ECs activated the mitochondrial pathway of apoptosis as determined by genomic DNA fragmentation, extensive mitochondrial fission, activation of the proapoptotic proteins BAK and BAX, and cytochrome c efflux from mitochondria. ITSN-1 knockdown acts as a proapoptotic signal that causes mitochondrial outer membrane permeabilization, dissipation of the mitochondrial membrane potential, and generation of reactive oxygen species. These effects were secondary to decreased activation of Erk1/2 and its direct activator MEK. Bcl-X(L) overexpression prevented BAX activation and the apoptotic ECs death induced by suppression of ITSN-1s. Our findings demonstrate a novel role of ITSN-1s as a negative regulator of the mitochondrial pathway-dependent apoptosis secondary to activation of the Erk1/2 survival signaling pathway. PMID:17405881

  11. Two Pathways Mediate Inter-Domain Allosteric Regulation in Pin1

    PubMed Central

    Guo, Jingjing; Pang, Xiaodong; Zhou, Huan-Xiang

    2014-01-01

    Summary Allostery is an essential means for regulating biomolecular functions and provides unique opportunities for drug design, yet our ability to elucidate allosteric mechanisms remains limited. Here, based on extensive molecular dynamics simulations, we present an atomistic picture of the pathways mediating the allosteric regulation of the PPIase domain of Pin1 by its WW domain. Two pathways jointly propagate the action of substrate-WW binding to produce closure and rigidification of three PPIase catalytic-site loops. One pathway preexists in the apo protein but remains dormant until substrate-WW binding completes the second. The reduction in conformational entropy and preorganization of the catalytic-site loops observed here may explain why substrate-WW binding enhances ligand affinity and catalytic activity of the PPIase domain, and suggest a combination drug therapy for Pin1-related diseases. Whereas the traditional view of allostery has emphasized conformational transition, our study uniquely identifies a distinct role of conformational dynamics in eliciting allostery. PMID:25543254

  12. GAME9 regulates the biosynthesis of steroidal alkaloids and upstream isoprenoids in the plant mevalonate pathway.

    PubMed

    Cárdenas, Pablo D; Sonawane, Prashant D; Pollier, Jacob; Vanden Bossche, Robin; Dewangan, Veena; Weithorn, Efrat; Tal, Lior; Meir, Sagit; Rogachev, Ilana; Malitsky, Sergey; Giri, Ashok P; Goossens, Alain; Burdman, Saul; Aharoni, Asaph

    2016-01-01

    Steroidal glycoalkaloids (SGAs) are cholesterol-derived molecules produced by solanaceous species. They contribute to pathogen defence but are toxic to humans and considered as anti-nutritional compounds. Here we show that GLYCOALKALOID METABOLISM 9 (GAME9), an APETALA2/Ethylene Response Factor, related to regulators of alkaloid production in tobacco and Catharanthus roseus, controls SGA biosynthesis. GAME9 knockdown and overexpression in tomato and potato alters expression of SGAs and upstream mevalonate pathway genes including the cholesterol biosynthesis gene STEROL SIDE CHAIN REDUCTASE 2 (SSR2). Levels of SGAs, C24-alkylsterols and the upstream mevalonate and cholesterol pathways intermediates are modified in these plants. Δ(7)-STEROL-C5(6)-DESATURASE (C5-SD) in the hitherto unresolved cholesterol pathway is a direct target of GAME9. Transactivation and promoter-binding assays show that GAME9 exerts its activity either directly or cooperatively with the SlMYC2 transcription factor as in the case of the C5-SD gene promoter. Our findings provide insight into the regulation of SGA biosynthesis and means for manipulating these metabolites in crops. PMID:26876023

  13. GAME9 regulates the biosynthesis of steroidal alkaloids and upstream isoprenoids in the plant mevalonate pathway

    PubMed Central

    Cárdenas, Pablo D.; Sonawane, Prashant D.; Pollier, Jacob; Vanden Bossche, Robin; Dewangan, Veena; Weithorn, Efrat; Tal, Lior; Meir, Sagit; Rogachev, Ilana; Malitsky, Sergey; Giri, Ashok P.; Goossens, Alain; Burdman, Saul; Aharoni, Asaph

    2016-01-01

    Steroidal glycoalkaloids (SGAs) are cholesterol-derived molecules produced by solanaceous species. They contribute to pathogen defence but are toxic to humans and considered as anti-nutritional compounds. Here we show that GLYCOALKALOID METABOLISM 9 (GAME9), an APETALA2/Ethylene Response Factor, related to regulators of alkaloid production in tobacco and Catharanthus roseus, controls SGA biosynthesis. GAME9 knockdown and overexpression in tomato and potato alters expression of SGAs and upstream mevalonate pathway genes including the cholesterol biosynthesis gene STEROL SIDE CHAIN REDUCTASE 2 (SSR2). Levels of SGAs, C24-alkylsterols and the upstream mevalonate and cholesterol pathways intermediates are modified in these plants. Δ(7)-STEROL-C5(6)-DESATURASE (C5-SD) in the hitherto unresolved cholesterol pathway is a direct target of GAME9. Transactivation and promoter-binding assays show that GAME9 exerts its activity either directly or cooperatively with the SlMYC2 transcription factor as in the case of the C5-SD gene promoter. Our findings provide insight into the regulation of SGA biosynthesis and means for manipulating these metabolites in crops. PMID:26876023

  14. MicroRNAs regulate signaling pathways in osteogenic differentiation of mesenchymal stem cells (Review)

    PubMed Central

    PENG, SHUPING; GAO, DAN; GAO, CHENGDE; WEI, PINGPIN; NIU, MAN; SHUAI, CIJUN

    2016-01-01

    Osteogenesis is a complex multi-step process involving the differentiation of mesenchymal stem cells (MSCs) into osteoblast progenitor cells, preosteoblasts, osteoblasts and osteocytes, and the crosstalk between multiple cell types for the formation and remodeling of bone. The signaling regulatory networks during osteogenesis include various components, including growth factors, transcription factors, micro (mi)RNAs and effectors, a number of which form feedback loops controlling the balance of osteogenic differentiation by positive or negative regulation. miRNAs have been found to be important regulators of osteogenic signaling pathways in multiple aspects and multiple signaling pathways. The present review focusses on the progress in elucidating the role of miRNA in the osteogenesis signaling networks of MSCs as a substitute for bone implantation the the field of bone tissue engineering. In particular, the review classifies which miRNAs promote or suppress the osteogenic process, and summarizes which signaling pathway these miRNAs are involved in. Improvements in knowledge of the characteristics of miRNAs in osteogenesis provide an important step for their application in translational investigations of bone tissue engineering and bone disease. PMID:27222009

  15. A Functional Genome-Wide In Vivo Screen Identifies New Regulators of Signalling Pathways during Early Xenopus Embryogenesis

    PubMed Central

    Zhang, Siwei; Li, Jingjing; Lea, Robert; Amaya, Enrique; Dorey, Karel

    2013-01-01

    Embryonic development requires exquisite regulation of several essential processes, such as patterning of tissues and organs, cell fate decisions, and morphogenesis. Intriguingly, these diverse processes are controlled by only a handful of signalling pathways, and mis-regulation in one or more of these pathways may result in a variety of congenital defects and diseases. Consequently, investigating how these signalling pathways are regulated at the molecular level is essential to understanding the mechanisms underlying vertebrate embryogenesis, as well as developing treatments for human diseases. Here, we designed and performed a large-scale gain-of-function screen in Xenopus embryos aimed at identifying new regulators of MAPK/Erk, PI3K/Akt, BMP, and TGF-β/Nodal signalling pathways. Our gain-of-function screen is based on the identification of gene products that alter the phosphorylation state of key signalling molecules, which report the activation state of the pathways. In total, we have identified 20 new molecules that regulate the activity of one or more signalling pathways during early Xenopus development. This is the first time that such a functional screen has been performed, and the findings pave the way toward a more comprehensive understanding of the molecular mechanisms regulating the activity of important signalling pathways under normal and pathological conditions. PMID:24244509

  16. The role of phosphatidylinositol signaling pathway in regulating serotonin-induced oocyte maturation in Mercenaria mercenaria

    NASA Astrophysics Data System (ADS)

    Wang, Qing; Zhang, Tao

    2011-05-01

    Serotonin (5-HT) has been found to stimulate meiotic maturation of oocytes in many molluscs. During maturation, several signaling pathways are involved, especially the phosphatidylinositol and cAMP pathways. In order to examine the possible role of the phosphatidylinositol signaling pathway in regulating oocyte maturation in Mercenaria mercenaria, the effects of the activator/inhibitor of phospholipase (PLC) and protein kinase C (PKC) on serotonin-induced maturation were studied. Results show that high-concentrations of neomycin (inhibitor of PLC) blocked oocyte maturation, while 9, 10-dimethyl-1, 2-benzanthracene (DMBA, activator of PLC) promoted oocyte maturation in the presence of serotonin. It was also found that in the presence of serotonin, phorbol 12-myristate 13-acetate (PMA, activator of PKC) inhibited oocyte maturation, while sphingosine (inhibitor of PKC) stimulated oocyte maturation. These results indicate that serotonin-induced oocyte maturation requires the activation of the phosphatidylinositol pathway. Decrease of PLC inhibited serotonin-induced oocyte maturation, whereas a decrease of PKC stimulated the maturation. Thus, our study indicates that serotonin promotes maturation of M. mercenaria oocytes through PLC stimulated increase in calcium ion concentration via inositol-1, 4, 5-trisphosphate (IP3) but not PKC.

  17. Drosophila Cyclin G Is a Regulator of the Notch Signalling Pathway during Wing Development

    PubMed Central

    Nagel, Anja C.; Szawinski, Jutta; Zimmermann, Mirjam; Preiss, Anette

    2016-01-01

    Notch signalling regulates a multitude of differentiation processes during Drosophila development. For example, Notch activity is required for proper wing vein differentiation which is hampered in mutants of either the receptor Notch, the ligand Delta or the antagonist Hairless. Moreover, the Notch pathway is involved in several aspects of Drosophila oogenesis as well. We have identified Drosophila Cyclin G (CycG) as a molecular interaction partner of Hairless, the major antagonist in the Notch signalling pathway, in vitro and in vivo. Loss of CycG was shown before to cause female sterility and to disturb the architecture of the egg shell. Nevertheless, Notch dependent processes during oogenesis appeared largely unaffected in cycG mutant egg chambers. Loss of CycG modified the dominant wing phenotypes of Notch, Delta and Hairless mutants. Whereas the Notch loss of function phenotype was ameliorated by a loss of CycG, the phenotypes of either Notch gain of function or of Delta or Hairless loss of function were enhanced. In contrast, loss of CycG had only a minor effect on the wing vein phenotype of mutants affecting the EGFR signalling pathway emphasizing the specificity of the interaction of CycG and Notch pathway members. PMID:26963612

  18. Regulation of the Nampt-mediated NAD salvage pathway and its therapeutic implications in pancreatic cancer.

    PubMed

    Ju, Huai-Qiang; Zhuang, Zhuo-Nan; Li, Hao; Tian, Tian; Lu, Yun-Xin; Fan, Xiao-Qiang; Zhou, Hai-Jun; Mo, Hai-Yu; Sheng, Hui; Chiao, Paul J; Xu, Rui-Hua

    2016-08-28

    Nicotinamide adenine dinucleotide (NAD) is a crucial cofactor for the redox reactions in the metabolic pathways of cancer cells that have elevated aerobic glycolysis (Warburg effect). Cancer cells are reported to rely on NAD recycling and inhibition of the NAD salvage pathway causes metabolic collapse and cell death. However, the underlying regulatory mechanisms and clinical implications for the NAD salvage pathway in pancreatic ductal adenocarcinoma (PDAC) remain unclear. This study showed that the expression of Nampt, the rate-limiting enzyme of the NAD salvage pathway, was significantly increased in PDAC cells and PDAC tissues. Additionally, inhibition of Nampt impaired tumor growth in vitro and tumorigenesis in vivo, which was accompanied by a decreased cellular NAD level and glycolytic activity. Mechanistically, the Nampt expression was independent of Kras and p16 status, but it was directly regulated by miR-206, which was inversely correlated with the expression of Nampt in PDAC tissues. Importantly, pharmacological inhibition of Nampt by its inhibitor, FK866, significantly enhanced the antitumor activity of gemcitabine in PDAC cells and in orthotopic xenograft mouse models. In conclusion, the present study revealed a novel regulatory mechanism for Nampt in PDAC and suggested that Nampt inhibition may override gemcitabine resistance by decreasing the NAD level and suppressing glycolytic activity, warranting further clinical investigation for pancreatic cancer treatment. PMID:27233476

  19. Berberine regulates neurite outgrowth through AMPK-dependent pathways by lowering energy status

    SciTech Connect

    Lu, Jiaqi; Cao, Yuanzhao; Cheng, Kuoyuan; Xu, Bo; Wang, Tianchang; Yang, Qi; Yang, Qin; Feng, Xudong; Xia, Qing

    2015-06-10

    As a widely used anti-bacterial agent and a metabolic inhibitor as well as AMP-activated protein kinase (AMPK) activator, berberine (BBR) has been shown to cross the blood–brain barrier. Its efficacy has been investigated in various disease models of the central nervous system. Neurite outgrowth is critical for nervous system development and is a highly energy-dependent process regulated by AMPK-related pathways. In the present study, we aimed to investigate the effects of BBR on AMPK activation and neurite outgrowth in neurons. The neurite outgrowth of primary rat cortical neurons at different stages of polarization was monitored after exposure of BBR. Intracellular energy level, AMPK activation and polarity-related pathways were also inspected. The results showed that BBR suppressed neurite outgrowth and affected cytoskeleton stability in the early stages of neuronal polarization, which was mediated by lowered energy status and AMPK activation. Liver kinase B1 and PI3K–Akt–GSK3β signaling pathways were also involved. In addition, mitochondrial dysfunction and endoplasmic reticulum stress contributed to the lowered energy status induced by BBR. This study highlighted the knowledge of the complex activities of BBR in neurons and corroborated the significance of energy status during the neuronal polarization. - Highlights: • BBR inhibited neurite outgrowth in early stages of neuronal development. • Lowered neuronal energy status was induced by BBR treatment. • Neuronal energy stress induced by BBR activated AMPK-related pathways. • BBR induced mitochondrial dysfunction and endoplasmic reticulum stress.

  20. Iro/IRX transcription factors negatively regulate Dpp/TGF-β pathway activity during intestinal tumorigenesis

    PubMed Central

    Martorell, Òscar; Barriga, Francisco M; Merlos-Suárez, Anna; Stephan-Otto Attolini, Camille; Casanova, Jordi; Batlle, Eduard; Sancho, Elena; Casali, Andreu

    2014-01-01

    Activating mutations in Wnt and EGFR/Ras signaling pathways are common in colorectal cancer (CRC). Remarkably, clonal co-activation of these pathways in the adult Drosophila midgut induces “tumor-like” overgrowths. Here, we show that, in these clones and in CRC cell lines, Dpp/TGF-β acts as a tumor suppressor. Moreover, we discover that the Iroquois/IRX-family-protein Mirror downregulates the transcription of core components of the Dpp pathway, reducing its tumor suppressor activity. We also show that this genetic interaction is conserved in human CRC cells, where the Iro/IRX proteins IRX3 and IRX5 diminish the response to TGF-β. IRX3 and IRX5 are upregulated in human adenomas, and their levels correlate inversely with the gene expression signature of response to TGF-β. In addition, Irx5 expression confers a growth advantage in the presence of TGF-β, but is selected against in its absence. Together, our results identify a set of Iro/IRX proteins as conserved negative regulators of Dpp/TGF-β activity. We propose that during the characteristic adenoma-to-carcinoma transition of human CRC, the activity of IRX proteins could reduce the sensitivity to the cytostatic effect of TGF-β, conferring a growth advantage to tumor cells prior to the acquisition of mutations in TGF-β pathway components. PMID:25296644

  1. Down-regulated Lotus japonicus GCR1 plants exhibit nodulation signalling pathways alteration.

    PubMed

    Rogato, Alessandra; Valkov, Vladimir Totev; Alves, Ludovico Martins; Apone, Fabio; Colucci, Gabriella; Chiurazzi, Maurizio

    2016-06-01

    G Protein Coupled Receptor (GPCRs) are integral membrane proteins involved in various signalling pathways by perceiving many extracellular signals and transducing them to heterotrimeric G proteins, which further transduce these signals to intracellular downstream effectors. GCR1 is the only reliable plant candidate as a member of the GPCRs superfamily. In the legume/rhizobia symbiotic interaction, G proteins are involved in signalling pathways controlling different steps of the nodulation program. In order to investigate the putative hierarchic role played by GCR1 in these symbiotic pathways we identified and characterized the Lotus japonicus gene encoding the seven transmembrane GCR1 protein. The detailed molecular and topological analyses of LjGCR1 expression patterns that are presented suggest a possible involvement in the early steps of nodule organogenesis. Furthermore, phenotypic analyses of independent transgenic RNAi lines, showing a significant LjGCR1 expression down regulation, suggest an epistatic action in the control of molecular markers of nodulation pathways, although no macroscopic symbiotic phenotypes could be revealed. PMID:27095401

  2. RICTOR involvement in the PI3K/AKT pathway regulation in melanocytes and melanoma

    PubMed Central

    Laugier, Florence; Finet-Benyair, Adeline; André, Jocelyne; Rachakonda, P. Sivaramakrishna; Kumar, Rajiv; Bensussan, Armand; Dumaz, Nicolas

    2015-01-01

    Several studies have highlighted the importance of the PI3K pathway in melanocytes and its frequent over-activation in melanoma. However, little is known about regulation of the PI3K pathway in melanocytic cells. We showed that normal human melanocytes are less sensitive to selective PI3K or mTOR inhibitors than to dual PI3K/mTOR inhibitors. The resistance to PI3K inhibitor was due to a rapid AKT reactivation limiting the inhibitor effect on proliferation. Reactivation of AKT was linked to a feedback mechanism involving the mTORC2 complex and in particular its scaffold protein RICTOR. RICTOR overexpression in melanocytes disrupted the negative feedback, activated the AKT pathway and stimulated clonogenicity highlighting the importance of this feedback to restrict melanocyte proliferation. We found that the RICTOR locus is frequently amplified and overexpressed in melanoma and that RICTOR over-expression in NRAS-transformed melanocytes stimulates their clonogenicity, demonstrating that RICTOR amplification can cooperate with NRAS mutation to stimulate melanoma proliferation. These results show that RICTOR plays a central role in PI3K pathway negative feedback in melanocytes and that its deregulation could be involved in melanoma development. PMID:26356562

  3. Fanconi anemia pathway regulates convergent transcription-induced cell death at trinucleotide repeats in human cells

    PubMed Central

    Chatterjee, Nimrat; Lin, Yunfu; Wilson, John H.

    2016-01-01

    Almost 20 incurable neurodegenerative disorders are caused by trinucleotide repeat (TNR) expansion beyond a certain threshold, with disease time of onset and severity positively correlating with repeat length. Typically, long TNRs display a bias toward further expansion and repeats continue to expand not only during germline transmissions from parents to offspring, but also remain highly unstable in somatic tissues of patients. Hence, understanding TNR instability mechanisms sheds light on underlying disease pathology. Recently, we showed that activated ATR is the major signal for convergent-transcription-induced cell death at CAG repeats and is regulated by the mismatch repair (MMR) pathway. Additionally, components of other DNA repair pathways such as transcription-coupled nucleotide excision repair (TC-NER) and R-loop resolution by RNaseH reduce cell death. Because activated ATR signals the Fanconi anemia (FA) pathway of interstrand crosslink DNA repair, we asked whether the FA pathway also modulates convergent-transcription-induced cell death at expanded CAG repeats. We show here that siRNA knockdown of FA components—FANCI, FANCJ, FANCM, FANCA, and FANCD2—decreases cell death, suggesting that FA proteins, like MMR proteins, are activators of cell death during convergent transcription.

  4. The Wnt/beta-catenin pathway regulates Gli-mediated Myf5 expression during somitogenesis.

    PubMed

    Borello, Ugo; Berarducci, Barbara; Murphy, Paula; Bajard, Lola; Buffa, Viviana; Piccolo, Stefano; Buckingham, Margaret; Cossu, Giulio

    2006-09-01

    Canonical Wnt/beta-catenin signaling regulates the activation of the myogenic determination gene Myf5 at the onset of myogenesis, but the underlying molecular mechanism is unknown. Here, we report that the Wnt signal is transduced in muscle progenitor cells by at least two Frizzled (Fz) receptors (Fz1 and/or Fz6), through the canonical beta-catenin pathway, in the epaxial domain of newly formed somites. We show that Myf5 activation is dramatically reduced by blocking the Wnt/beta-catenin pathway in somite progenitor cells, whereas expression of activated beta-catenin is sufficient to activate Myf5 in somites but not in the presomitic mesoderm. In addition, we identified Tcf/Lef sequences immediately 5' to the Myf5 early epaxial enhancer. These sites determine the correct spatiotemporal expression of Myf5 in the epaxial domain of the somite, mediating the synergistic action of the Wnt/beta-catenin and the Shh/Gli pathways. Taken together, these results demonstrate that Myf5 is a direct target of Wnt/beta-catenin, and that its full activation requires a cooperative interaction between the canonical Wnt and the Shh/Gli pathways in muscle progenitor cells. PMID:16936075

  5. Reciprocal regulation of the nitric oxide and cyclooxygenase pathway in pathophysiology: relevance and clinical implications

    PubMed Central

    Kim, Sangwon F.; Mollace, Vincenzo

    2013-01-01

    The nitric oxide (NO) and cyclooxygenase (COX) pathways share a number of similarities. Nitric oxide is the mediator generated from the NO synthase (NOS) pathway, and COX converts arachidonic acid to prostaglandins, prostacyclin, and thromboxane A2. Two major forms of NOS and COX have been identified to date. The constitutive isoforms critically regulate several physiological states. The inducible isoforms are overexpressed during inflammation in a variety of cells, producing large amounts of NO and prostaglandins, which may underlie pathological processes. The cross-talk between the COX and NOS pathways was initially reported by Salvemini and colleagues in 1993, when they demonstrated in a series of in vitro and in vivo studies that NO activates the COX enzymes to produce increased amounts of prostaglandins. Those studies led to the concept that COX enzymes represent important endogenous “receptor” targets for amplifying or modulating the multifaceted roles of NO in physiology and pathology. Since then, numerous studies have furthered our mechanistic understanding of these interactions in pathophysiological settings and delineated potential clinical outcomes. In addition, emerging evidence suggests that the canonical nitroxidative species (NO, superoxide, and/or peroxynitrite) modulate biosynthesis of prostaglandins through non-COX-related pathways. This article provides a comprehensive state-of-the art overview in this area. PMID:23389111

  6. Improving fatty acids production by engineering dynamic pathway regulation and metabolic control

    PubMed Central

    Xu, Peng; Li, Lingyun; Zhang, Fuming; Stephanopoulos, Gregory; Koffas, Mattheos

    2014-01-01

    Global energy demand and environmental concerns have stimulated increasing efforts to produce carbon-neutral fuels directly from renewable resources. Microbially derived aliphatic hydrocarbons, the petroleum-replica fuels, have emerged as promising alternatives to meet this goal. However, engineering metabolic pathways with high productivity and yield requires dynamic redistribution of cellular resources and optimal control of pathway expression. Here we report a genetically encoded metabolic switch that enables dynamic regulation of fatty acids (FA) biosynthesis in Escherichia coli. The engineered strains were able to dynamically compensate the critical enzymes involved in the supply and consumption of malonyl-CoA and efficiently redirect carbon flux toward FA biosynthesis. Implementation of this metabolic control resulted in an oscillatory malonyl-CoA pattern and a balanced metabolism between cell growth and product formation, yielding 15.7- and 2.1-fold improvement in FA titer compared with the wild-type strain and the strain carrying the uncontrolled metabolic pathway. This study provides a new paradigm in metabolic engineering to control and optimize metabolic pathways facilitating the high-yield production of other malonyl-CoA–derived compounds. PMID:25049420

  7. A R2R3-MYB Transcription Factor from Epimedium sagittatum Regulates the Flavonoid Biosynthetic Pathway

    PubMed Central

    Lv, Haiyan; Luo, Ming; Zeng, Shaohua; Pattanaik, Sitakanta; Yuan, Ling; Wang, Ying

    2013-01-01

    Herba epimedii (Epimedium), a traditional Chinese medicine, has been widely used as a kidney tonic and antirheumatic medicine for thousands of years. The bioactive components in herba epimedii are mainly prenylated flavonol glycosides, end-products of the flavonoid pathway. Epimedium species are also used as garden plants due to the colorful flowers and leaves. Many R2R3-MYB transcription factors (TFs) have been identified to regulate the flavonoid and anthocyanin biosynthetic pathways. However, little is known about the R2R3-MYB TFs involved in regulation of the flavonoid pathway in Epimedium. Here, we reported the isolation and functional characterization of the first R2R3-MYB TF (EsMYBA1) from Epimedium sagittatum (Sieb. Et Zucc.) Maxim. Conserved domains and phylogenetic analysis showed that EsMYBA1 belonged to the subgroup 6 clade (anthocyanin-related MYB clade) of R2R3-MYB family, which includes Arabidopsis AtPAP1, apple MdMYB10 and legume MtLAP1. EsMYBA1 was preferentially expressed in leaves, especially in red leaves that contain higher content of anthocyanin. Alternative splicing of EsMYBA1 resulted in three transcripts and two of them encoded a MYB-related protein. Yeast two-hybrid and transient luciferase expression assay showed that EsMYBA1 can interact with several bHLH regulators of the flavonoid pathway and activate the promoters of dihydroflavonol 4-reductase (DFR) and anthocyanidin synthase (ANS). In both transgenic tobacco and Arabidopsis, overexpression of EsMYBA1 induced strong anthocyanin accumulation in reproductive and/or vegetative tissues via up-regulation of the main flavonoid-related genes. Furthermore, transient expression of EsMYBA1 in E. sagittatum leaves by Agrobacterium infiltration also induced anthocyanin accumulation in the wounded area. This first functional characterization of R2R3-MYB TFs in Epimedium species will promote further studies of the flavonoid biosynthesis and regulation in medicinal plants. PMID:23936468

  8. The planar cell polarity pathway drives pathogenesis of chronic lymphocytic leukemia by the regulation of B-lymphocyte migration.

    PubMed

    Kaucká, Markéta; Plevová, Karla; Pavlová, Sárka; Janovská, Pavlína; Mishra, Archana; Verner, Jan; Procházková, Jirina; Krejcí, Pavel; Kotasková, Jana; Ovesná, Petra; Tichy, Boris; Brychtová, Yvona; Doubek, Michael; Kozubík, Alois; Mayer, Jirí; Pospísilová, Sárka; Bryja, Vítezslav

    2013-03-01

    The planar cell polarity (PCP) pathway is a conserved pathway that regulates cell migration and polarity in various contexts. Here we show that key PCP pathway components such as Vangl2, Celsr1, Prickle1, FZD3, FZD7, Dvl2, Dvl3, and casein kinase 1 (CK1)-ε are upregulated in B lymphocytes of patients with chronic lymphocytic leukemia (CLL). Elevated levels of PCP proteins accumulate in advanced stages of the disease. Here, we show that PCP pathway is required for the migration and transendothelial invasion of CLL cells and that patients with high expression of PCP genes, FZD3, FZD7, and PRICKLE1, have a less favorable clinical prognosis. Our findings establish that the PCP pathway acts as an important regulator of CLL cell migration and invasion. PCP proteins represent an important class of molecules regulating pathogenic interaction of CLL cells with their microenvironment. PMID:23338609

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

    PubMed Central

    Bargmann, William; Bose, Henry R.

    2014-01-01

    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

  10. [Dual-role regulations of canonical Wnt/beta-catenin signaling pathway].

    PubMed

    Liu, Yang; Zhang, Chen-guang; Zhou, Chun-yan

    2010-04-18

    In recent years, Wnt/beta-catenin signaling has been identified as a key player in embryogenesis and human diseases. Canonical Wnt signaling pathway is controlled by a variety of classic molecules like Wnt, beta-catenin, Axin, APC, GSK-3beta and CK1, which interact and coordinate to regulate the expressions of cell signaling molecules. The latest evidences suggest that some components of the Wnt/beta-catenin signaling, like APC, GSK-3beta, CK1, Dkk2 and WISE, play dual roles different from what they have been thought previously. Here we reviewed some recent discoveries on the canonical Wnt/beta-catenin signaling pathway to provide some new ideas and principles for signaling transduction studies. PMID:20396373

  11. p24 family proteins: key players in the regulation of trafficking along the secretory pathway.

    PubMed

    Pastor-Cantizano, Noelia; Montesinos, Juan Carlos; Bernat-Silvestre, César; Marcote, María Jesús; Aniento, Fernando

    2016-07-01

    p24 family proteins have been known for a long time, but their functions have remained elusive. However, they are emerging as essential regulators of protein trafficking along the secretory pathway, influencing the composition, structure, and function of different organelles in the pathway, especially the ER and the Golgi apparatus. In addition, they appear to modulate the transport of specific cargos, including GPI-anchored proteins, G-protein-coupled receptors, or K/HDEL ligands. As a consequence, they have been shown to play specific roles in signaling, development, insulin secretion, and the pathogenesis of Alzheimer's disease. The search of new putative ligands may open the way to discover new functions for this fascinating family of proteins. PMID:26224213

  12. Parkin and PINK1 function in a vesicular trafficking pathway regulating mitochondrial quality control

    PubMed Central

    McLelland, Gian-Luca; Soubannier, Vincent; Chen, Carol X; McBride, Heidi M; Fon, Edward A

    2014-01-01

    Mitochondrial dysfunction has long been associated with Parkinson's disease (PD). Parkin and PINK1, two genes associated with familial PD, have been implicated in the degradation of depolarized mitochondria via autophagy (mitophagy). Here, we describe the involvement of parkin and PINK1 in a vesicular pathway regulating mitochondrial quality control. This pathway is distinct from canonical mitophagy and is triggered by the generation of oxidative stress from within mitochondria. Wild-type but not PD-linked mutant parkin supports the biogenesis of a population of mitochondria-derived vesicles (MDVs), which bud off mitochondria and contain a specific repertoire of cargo proteins. These MDVs require PINK1 expression and ultimately target to lysosomes for degradation. We hypothesize that loss of this parkin- and PINK1-dependent trafficking mechanism impairs the ability of mitochondria to selectively degrade oxidized and damaged proteins leading, over time, to the mitochondrial dysfunction noted in PD. PMID:24446486

  13. Autopalmitoylation of TEAD proteins regulates transcriptional output of the Hippo pathway.

    PubMed

    Chan, PuiYee; Han, Xiao; Zheng, Baohui; DeRan, Michael; Yu, Jianzhong; Jarugumilli, Gopala K; Deng, Hua; Pan, Duojia; Luo, Xuelian; Wu, Xu

    2016-04-01

    TEA domain (TEAD) transcription factors bind to the coactivators YAP and TAZ and regulate the transcriptional output of the Hippo pathway, playing critical roles in organ size control and tumorigenesis. Protein S-palmitoylation attaches a fatty acid, palmitate, to cysteine residues and regulates protein trafficking, membrane localization and signaling activities. Using activity-based chemical probes, we discovered that human TEADs possess intrinsic palmitoylating enzyme-like activities and undergo autopalmitoylation at evolutionarily conserved cysteine residues under physiological conditions. We determined the crystal structures of lipid-bound TEADs and found that the lipid chain of palmitate inserts into a conserved deep hydrophobic pocket. Strikingly, palmitoylation did not alter TEAD's localization, but it was required for TEAD's binding to YAP and TAZ and was dispensable for its binding to the Vgll4 tumor suppressor. Moreover, palmitoylation-deficient TEAD mutants impaired TAZ-mediated muscle differentiation in vitro and tissue overgrowth mediated by the Drosophila YAP homolog Yorkie in vivo. Our study directly links autopalmitoylation to the transcriptional regulation of the Hippo pathway. PMID:26900866

  14. Integrins modulate the Egfr signaling pathway to regulate tendon cell differentiation in the Drosophila embryo.

    PubMed

    Martin-Bermudo, M D

    2000-06-01

    Changes in the extracellular matrix (ECM) govern the differentiation of many cell types during embryogenesis. Integrins are cell matrix receptors that play a major role in cell-ECM adhesion and in transmitting signals from the ECM inside the cell to regulate gene expression. In this paper, it is shown that the PS integrins are required at the muscle attachment sites of the Drosophila embryo to regulate tendon cell differentiation. The analysis of the requirements of the individual alpha subunits, alphaPS1 and alphaPS2, demonstrates that both PS1 and PS2 integrins are involved in this process. In the absence of PS integrin function, the expression of tendon cell-specific genes such as stripe and beta1 tubulin is not maintained. In addition, embryos lacking the PS integrins also exhibit reduced levels of activated MAPK. This reduction is probably due to a downregulation of the Epidermal Growth Factor receptor (Egfr) pathway, since an activated form of the Egfr can rescue the phenotype of embryos mutant for the PS integrins. Furthermore, the levels of the Egfr ligand Vein at the muscle attachment sites are reduced in PS mutant embryos. Altogether, these results lead to a model in which integrin-mediated adhesion plays a role in regulating tendon cell differentiation by modulating the activity of the Egfr pathway at the level of its ligand Vein. PMID:10821759

  15. Spatial Regulation of Root Growth: Placing the Plant TOR Pathway in a Developmental Perspective.

    PubMed

    Barrada, Adam; Montané, Marie-Hélène; Robaglia, Christophe; Menand, Benoît

    2015-01-01

    Plant cells contain specialized structures, such as a cell wall and a large vacuole, which play a major role in cell growth. Roots follow an organized pattern of development, making them the organs of choice for studying the spatio-temporal regulation of cell proliferation and growth in plants. During root growth, cells originate from the initials surrounding the quiescent center, proliferate in the division zone of the meristem, and then increase in length in the elongation zone, reaching their final size and differentiation stage in the mature zone. Phytohormones, especially auxins and cytokinins, control the dynamic balance between cell division and differentiation and therefore organ size. Plant growth is also regulated by metabolites and nutrients, such as the sugars produced by photosynthesis or nitrate assimilated from the soil. Recent literature has shown that the conserved eukaryotic TOR (target of rapamycin) kinase pathway plays an important role in orchestrating plant growth. We will summarize how the regulation of cell proliferation and cell expansion by phytohormones are at the heart of root growth and then discuss recent data indicating that the TOR pathway integrates hormonal and nutritive signals to orchestrate root growth. PMID:26295391

  16. The Nuclear Receptor, RORγ, Regulates Pathways Necessary for Breast Cancer Metastasis.

    PubMed

    Oh, Tae Gyu; Wang, Shu-Ching M; Acharya, Bipul R; Goode, Joel M; Graham, J Dinny; Clarke, Christine L; Yap, Alpha S; Muscat, George E O

    2016-04-01

    We have previously reported that RORγ expression was decreased in ER-ve breast cancer, and increased expression improves clinical outcomes. However, the underlying RORγ dependent mechanisms that repress breast carcinogenesis have not been elucidated. Here we report that RORγ negatively regulates the oncogenic TGF-β/EMT and mammary stem cell (MaSC) pathways, whereas RORγ positively regulates DNA-repair. We demonstrate that RORγ expression is: (i) decreased in basal-like subtype cancers, and (ii) inversely correlated with histological grade and drivers of carcinogenesis in breast cancer cohorts. Furthermore, integration of RNA-seq and ChIP-chip data reveals that RORγ regulates the expression of many genes involved in TGF-β/EMT-signaling, DNA-repair and MaSC pathways (including the non-coding RNA, LINC00511). In accordance, pharmacological studies demonstrate that an RORγ agonist suppresses breast cancer cell viability, migration, the EMT transition (microsphere outgrowth) and mammosphere-growth. In contrast, RNA-seq demonstrates an RORγ inverse agonist induces TGF-β/EMT-signaling. These findings suggest pharmacological modulation of RORγ activity may have utility in breast cancer. PMID:27211549

  17. Spatial Regulation of Root Growth: Placing the Plant TOR Pathway in a Developmental Perspective

    PubMed Central

    Barrada, Adam; Montané, Marie-Hélène; Robaglia, Christophe; Menand, Benoît

    2015-01-01

    Plant cells contain specialized structures, such as a cell wall and a large vacuole, which play a major role in cell growth. Roots follow an organized pattern of development, making them the organs of choice for studying the spatio-temporal regulation of cell proliferation and growth in plants. During root growth, cells originate from the initials surrounding the quiescent center, proliferate in the division zone of the meristem, and then increase in length in the elongation zone, reaching their final size and differentiation stage in the mature zone. Phytohormones, especially auxins and cytokinins, control the dynamic balance between cell division and differentiation and therefore organ size. Plant growth is also regulated by metabolites and nutrients, such as the sugars produced by photosynthesis or nitrate assimilated from the soil. Recent literature has shown that the conserved eukaryotic TOR (target of rapamycin) kinase pathway plays an important role in orchestrating plant growth. We will summarize how the regulation of cell proliferation and cell expansion by phytohormones are at the heart of root growth and then discuss recent data indicating that the TOR pathway integrates hormonal and nutritive signals to orchestrate root growth. PMID:26295391

  18. The CRTC1-SIK1 Pathway Regulates Entrainment of the Circadian Clock

    PubMed Central

    Jagannath, Aarti; Butler, Rachel; Godinho, Sofia I.H.; Couch, Yvonne; Brown, Laurence A.; Vasudevan, Sridhar R.; Flanagan, Kevin C.; Anthony, Daniel; Churchill, Grant C.; Wood, Matthew J.A.; Steiner, Guido; Ebeling, Martin; Hossbach, Markus; Wettstein, Joseph G.; Duffield, Giles E.; Gatti, Silvia; Hankins, Mark W.; Foster, Russell G.; Peirson, Stuart N.

    2013-01-01

    Summary Retinal photoreceptors entrain the circadian system to the solar day. This photic resetting involves cAMP response element binding protein (CREB)-mediated upregulation of Per genes within individual cells of the suprachiasmatic nuclei (SCN). Our detailed understanding of this pathway is poor, and it remains unclear why entrainment to a new time zone takes several days. By analyzing the light-regulated transcriptome of the SCN, we have identified a key role for salt inducible kinase 1 (SIK1) and CREB-regulated transcription coactivator 1 (CRTC1) in clock re-setting. An entrainment stimulus causes CRTC1 to coactivate CREB, inducing the expression of Per1 and Sik1. SIK1 then inhibits further shifts of the clock by phosphorylation and deactivation of CRTC1. Knockdown of Sik1 within the SCN results in increased behavioral phase shifts and rapid re-entrainment following experimental jet lag. Thus SIK1 provides negative feedback, acting to suppress the effects of light on the clock. This pathway provides a potential target for the regulation of circadian rhythms. PMID:23993098

  19. The Nuclear Receptor, RORγ, Regulates Pathways Necessary for Breast Cancer Metastasis

    PubMed Central

    Oh, Tae Gyu; Wang, Shu-Ching M.; Acharya, Bipul R.; Goode, Joel M.; Graham, J. Dinny; Clarke, Christine L.; Yap, Alpha S.; Muscat, George E.O.

    2016-01-01

    We have previously reported that RORγ expression was decreased in ER − ve breast cancer, and increased expression improves clinical outcomes. However, the underlying RORγ dependent mechanisms that repress breast carcinogenesis have not been elucidated. Here we report that RORγ negatively regulates the oncogenic TGF-β/EMT and mammary stem cell (MaSC) pathways, whereas RORγ positively regulates DNA-repair. We demonstrate that RORγ expression is: (i) decreased in basal-like subtype cancers, and (ii) inversely correlated with histological grade and drivers of carcinogenesis in breast cancer cohorts. Furthermore, integration of RNA-seq and ChIP-chip data reveals that RORγ regulates the expression of many genes involved in TGF-β/EMT-signaling, DNA-repair and MaSC pathways (including the non-coding RNA, LINC00511). In accordance, pharmacological studies demonstrate that an RORγ agonist suppresses breast cancer cell viability, migration, the EMT transition (microsphere outgrowth) and mammosphere-growth. In contrast, RNA-seq demonstrates an RORγ inverse agonist induces TGF-β/EMT-signaling. These findings suggest pharmacological modulation of RORγ activity may have utility in breast cancer. PMID:27211549

  20. MicroRNA-142-3p Negatively Regulates Canonical Wnt Signaling Pathway

    PubMed Central

    Hu, Tanyu; Phiwpan, Krung; Guo, Jitao; Zhang, Wei; Guo, Jie; Zhang, Zhongmei; Zou, Mangge; Zhang, Xuejie; Zhang, Jianhua

    2016-01-01

    Wnt/β-catenin signaling pathway plays essential roles in mammalian development and tissue homeostasis. MicroRNAs (miRNAs) are a class of regulators involved in modulating this pathway. In this study, we screened miRNAs regulating Wnt/β-catenin signaling by using a TopFlash based luciferase reporter. Surprisingly, we found that miR-142 inhibited Wnt/β-catenin signaling, which was inconsistent with a recent study showing that miR-142-3p targeted Adenomatous Polyposis Coli (APC) to upregulate Wnt/β-catenin signaling. Due to the discordance, we elaborated experiments by using extensive mutagenesis, which demonstrated that the stem-loop structure was important for miR-142 to efficiently suppress Wnt/β-catenin signaling. Moreover, the inhibitory effect of miR-142 relies on miR-142-3p rather than miR-142-5p. Further, we found that miR-142-3p directly modulated translation of Ctnnb1 mRNA (encoding β-catenin) through binding to its 3’ untranslated region (3’ UTR). Finally, miR-142 was able to repress cell cycle progression by inhibiting active Wnt/β-catenin signaling. Thus, our findings highlight the inhibitory role of miR-142-3p in Wnt/β-catenin signaling, which help to understand the complex regulation of Wnt/β-catenin signaling. PMID:27348426

  1. Insulin and mTOR Pathway Regulate HDAC3-Mediated Deacetylation and Activation of PGK1

    PubMed Central

    Wang, Shiwen; Jiang, Bowen; Zhang, Tengfei; Liu, Lixia; Wang, Yi; Wang, Yiping; Chen, Xiufei; Lin, Huaipeng; Zhou, Lisha; Xia, Yukun; Chen, Leilei; Yang, Chen; Xiong, Yue; Ye, Dan; Guan, Kun-Liang

    2015-01-01

    Phosphoglycerate kinase 1 (PGK1) catalyzes the reversible transfer of a phosphoryl group from 1, 3-bisphosphoglycerate (1, 3-BPG) to ADP, producing 3-phosphoglycerate (3-PG) and ATP. PGK1 plays a key role in coordinating glycolytic energy production with one-carbon metabolism, serine biosynthesis, and cellular redox regulation. Here, we report that PGK1 is acetylated at lysine 220 (K220), which inhibits PGK1 activity by disrupting the binding with its substrate, ADP. We have identified KAT9 and HDAC3 as the potential acetyltransferase and deacetylase, respectively, for PGK1. Insulin promotes K220 deacetylation to stimulate PGK1 activity. We show that the PI3K/AKT/mTOR pathway regulates HDAC3 S424 phosphorylation, which promotes HDAC3-PGK1 interaction and PGK1 K220 deacetylation. Our study uncovers a previously unknown mechanism for the insulin and mTOR pathway in regulation of glycolytic ATP production and cellular redox potential via HDAC3-mediated PGK1 deacetylation. PMID:26356530

  2. Unraveling the Specific Regulation of the Central Pathway for Anaerobic Degradation of 3-Methylbenzoate*

    PubMed Central

    Juárez, Javier F.; Liu, Huixiang; Zamarro, María T.; McMahon, Stephen; Liu, Huanting; Naismith, James H.; Eberlein, Christian; Boll, Matthias; Carmona, Manuel; Díaz, Eduardo

    2015-01-01

    The mbd cluster encodes the anaerobic degradation of 3-methylbenzoate in the β-proteobacterium Azoarcus sp. CIB. The specific transcriptional regulation circuit that controls the expression of the mbd genes was investigated. The PO, PB1, and P3R promoters responsible for the expression of the mbd genes, their cognate MbdR transcriptional repressor, as well as the MbdR operator regions (ATACN10GTAT) have been characterized. The three-dimensional structure of MbdR has been solved revealing a conformation similar to that of other TetR family transcriptional regulators. The first intermediate of the catabolic pathway, i.e. 3-methylbenzoyl-CoA, was shown to act as the inducer molecule. An additional MbdR-dependent promoter, PA, which contributes to the expression of the CoA ligase that activates 3-methylbenzoate to 3-methylbenzoyl-CoA, was shown to be necessary for an efficient induction of the mbd genes. Our results suggest that the mbd cluster recruited a regulatory system based on the MbdR regulator and its target promoters to evolve a distinct central catabolic pathway that is only expressed for the anaerobic degradation of aromatic compounds that generate 3-methylbenzoyl-CoA as the central metabolite. All these results highlight the importance of the regulatory systems in the evolution and adaptation of bacteria to the anaerobic degradation of aromatic compounds. PMID:25795774

  3. MicroRNA-221 and -222 Regulate Radiation Sensitivity by Targeting the PTEN Pathway

    SciTech Connect

    Zhang Chunzhi; Kang Chunsheng; Wang Ping; Cao Yongzhen; Lv Zhonghong; Yu Shizhu; Wang Guangxiu; Zhang Anling; Jia Zhifan; Han Lei; Yang Chunying; Ishiyama, Hiromichi; Teh, Bin S.; Xu Bo; Pu Peiyu

    2011-05-01

    Purpose: MicroRNAs (miRNAs) are noncoding RNAs inhibiting expression of numerous target genes by posttranscriptional regulation. miRNA-221 and miRNA-222 (miRNA-221/-222) expression is elevated in radioresistant tumor cell lines; however, it is not known whether and how miRNAs control cellular responses to ionizing irradiation. Methods and Materials: We used bioinformatic analyses, luciferase reporter assay, and genetic knockdown and biochemical assays to characterize the regulation pathways of miRNA-221/-222 in response to radiation treatment. Results: We identified the PTEN gene as a target of miRNA-221/-222. Furthermore, we found that knocking down miRNA-221/-222 by antisense oligonucleotides upregulated PTEN expression. Upregulated PTEN expression suppressed AKT activity and increased radiation-induced apoptosis, resulting in enhancement of radiosensitivity in tumor cells. Conclusions: miRNA-221/-222 control radiation sensitivity by regulating the PTEN/AKT pathway and can be explored as novel targets for radiosensitization.

  4. CREB-binding protein regulates lung cancer growth by targeting MAPK and CPSF4 signaling pathway.

    PubMed

    Tang, Zhipeng; Yu, Wendan; Zhang, Changlin; Zhao, Shilei; Yu, Zhenlong; Xiao, Xiangsheng; Tang, Ranran; Xuan, Yang; Yang, Wenjing; Hao, Jiaojiao; Xu, Tingting; Zhang, Qianyi; Huang, Wenlin; Deng, Wuguo; Guo, Wei

    2016-02-01

    CBP (CREB-binding protein) is a transcriptional co-activator which possesses HAT (histone acetyltransferases) activity and participates in many biological processes, including embryonic development, growth control and homeostasis. However, its roles and the underlying mechanisms in the regulation of carcinogenesis and tumor development remain largely unknown. Here we investigated the molecular mechanisms and potential targets of CBP involved in tumor growth and survival in lung cancer cells. Elevated expression of CBP was detected in lung cancer cells and tumor tissues compared to the normal lung cells and tissues. Knockdown of CBP by siRNA or inhibition of its HAT activity using specific chemical inhibitor effectively suppressed cell proliferation, migration and colony formation and induced apoptosis in lung cancer cells by inhibiting MAPK and activating cytochrome C/caspase-dependent signaling pathways. Co-immunoprecipitation and immunofluorescence analyses revealed the co-localization and interaction between CBP and CPSF4 (cleavage and polyadenylation specific factor 4) proteins in lung cancer cells. Knockdown of CPSF4 inhibited hTERT transcription and cell growth induced by CBP, and vice versa, demonstrating the synergetic effect of CBP and CPSF4 in the regulation of lung cancer cell growth and survival. Moreover, we found that high expression of both CBP and CPSF4 predicted a poor prognosis in the patients with lung adenocarcinomas. Collectively, our results indicate that CBP regulates lung cancer growth by targeting MAPK and CPSF4 signaling pathways. PMID:26628108

  5. Src promotes cutaneous wound healing by regulating MMP-2 through the ERK pathway

    PubMed Central

    WU, XUE; YANG, LONGLONG; ZHENG, ZHAO; LI, ZHENZHEN; SHI, JIHONG; LI, YAN; HAN, SHICHAO; GAO, JIANXIN; TANG, CHAOWU; SU, LINLIN; HU, DAHAI

    2016-01-01

    Wound healing is a highly orchestrated, multistep process, and delayed wound healing is a significant symptomatic clinical problem. Keratinocyte migration and re-epithelialization play the most important roles in wound healing, as they determine the rate of wound healing. In our previous study, we found that Src, one of the oldest proto-oncogenes encoding a membrane-associated, non-receptor protein tyrosine kinase, promotes keratinocyte migration. We therefore hypothesized that Src promotes wound healing through enhanced keratinocyte migration. In order to test this hypothesis, vectors for overexpressing Src and small interfering RNAs (siRNAs) for silencing of Src were used in the present study. We found that the overexpression of Src accelerated keratinocyte migration in vitro and promoted wound healing in vivo without exerting a marked effect on cell proliferation. The extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) signaling pathways play important roles in Src-accelerated keratinocyte migration. Further experiments demonstrated that Src induced the protein expression of matrix metallopro-teinase-2 (MMP-2) and decreased the protein expression of E-cadherin. We suggest that ERK signaling is involved in the Src-mediated regulation of MMP-2 expression. The present study provided evidence that Src promotes keratinocyte migration and cutaneous wound healing, in which the regulation of MMP-2 through the ERK pathway plays an important role, and thus we also demonstrated a potential therapeutic role for Src in cutaneous wound healing. PMID:26821191

  6. Graphics processing units as tools to predict mechanisms of biological signaling pathway regulation

    NASA Astrophysics Data System (ADS)

    McCarter, Patrick; Elston, Timothy; Nagiek, Michal; Dohlman, Henrik

    2013-04-01

    Biochemical and genomic studies have revealed protein components of S. cerevisiae (yeast) signal transduction networks. These networks allow the transmission of extracellular signals to the cell nucleus through coordinated biochemical interactions, resulting in direct responses to specific external stimuli. The coordination and regulation mechanisms of proteins in these networks have not been fully characterized. Thus, in this work we develop systems of ordinary differential equations to characterize processes that regulate signaling pathways. We employ graphics processing units (GPUs) in high performance computing environments to search in parallel through substantially more comprehensive parameter sets than allowed by personal computers. As a result, we are able to parameterize larger models with experimental data, leading to an increase in our model prediction capabilities. Thus far these models have helped to identify specific mechanisms such as positive and negative feedback loops that control network protein activity. We ultimately believe that the use of GPUs in biochemical signal transduction pathway modeling will help to discern how regulation mechanisms allow cells to respond to multiple external stimuli.

  7. Unraveling the specific regulation of the central pathway for anaerobic degradation of 3-methylbenzoate.

    PubMed

    Juárez, Javier F; Liu, Huixiang; Zamarro, María T; McMahon, Stephen; Liu, Huanting; Naismith, James H; Eberlein, Christian; Boll, Matthias; Carmona, Manuel; Díaz, Eduardo

    2015-05-01

    The mbd cluster encodes the anaerobic degradation of 3-methylbenzoate in the β-proteobacterium Azoarcus sp. CIB. The specific transcriptional regulation circuit that controls the expression of the mbd genes was investigated. The PO, PB 1, and P3 R promoters responsible for the expression of the mbd genes, their cognate MbdR transcriptional repressor, as well as the MbdR operator regions (ATACN10GTAT) have been characterized. The three-dimensional structure of MbdR has been solved revealing a conformation similar to that of other TetR family transcriptional regulators. The first intermediate of the catabolic pathway, i.e. 3-methylbenzoyl-CoA, was shown to act as the inducer molecule. An additional MbdR-dependent promoter, PA, which contributes to the expression of the CoA ligase that activates 3-methylbenzoate to 3-methylbenzoyl-CoA, was shown to be necessary for an efficient induction of the mbd genes. Our results suggest that the mbd cluster recruited a regulatory system based on the MbdR regulator and its target promoters to evolve a distinct central catabolic pathway that is only expressed for the anaerobic degradation of aromatic compounds that generate 3-methylbenzoyl-CoA as the central metabolite. All these results highlight the importance of the regulatory systems in the evolution and adaptation of bacteria to the anaerobic degradation of aromatic compounds. PMID:25795774

  8. Cross talk of signaling pathways in the regulation of the glucocorticoid receptor function.

    PubMed

    Davies, Laura; Karthikeyan, Nirupama; Lynch, James T; Sial, Elin-Alia; Gkourtsa, Areti; Demonacos, Constantinos; Krstic-Demonacos, Marija

    2008-06-01

    Several posttranslational modifications including phosphorylation have been detected on the glucocorticoid receptor (GR). However, the interdependence and combinatorial regulation of these modifications and their role in GR functions are poorly understood. We studied the effects of c-Jun N-terminal kinase (JNK)-dependent phosphorylation of GR on its sumoylation status and the impact that these modifications have on GR transcriptional activity. GR is targeted for phosphorylation at serine 246 (S246) by the JNK protein family in a rapid and transient manner. The levels of S246 phosphorylation of endogenous GR increased significantly in cells treated with UV radiation that activates JNK. S246 GR phosphorylation by JNK facilitated subsequent GR sumoylation at lysines 297 and 313. GR sumoylation increased with JNK activation and was inhibited in cells treated with JNK inhibitor. GR sumoylation in cells with activated JNK was mediated preferentially by small ubiquitin-like modifier (SUMO)2 rather than SUMO1. An increase in GR transcriptional activity was observed after inhibition of JNK or SUMO pathways and suppression of GR transcriptional activity after activation of both pathways in cells transfected with GR-responsive reporter genes. Endogenous GR transcriptional activity was inhibited on endogenous target genes IGF binding protein (IGFBP) and glucocorticoid-induced leucine zipper (GILZ) when JNK and SUMO pathways were induced individually or simultaneously. Activation of both of these signals inhibited GR-mediated regulation of human inhibitor of apoptosis gene (hIAP), whereas simultaneous activation had no effect. We conclude that phosphorylation aids GR sumoylation and that cross talk of JNK and SUMO pathways fine tune GR transcriptional activity in a target gene-specific manner, thereby modulating the hormonal response of cells exposed to stress. PMID:18337589

  9. UHRF1 regulation of the Keap1-Nrf2 pathway in pancreatic cancer contributes to oncogenesis.

    PubMed

    Abu-Alainin, Wafa; Gana, Thompson; Liloglou, Triantafillos; Olayanju, Adedamola; Barrera, Lawrence N; Ferguson, Robert; Campbell, Fiona; Andrews, Timothy; Goldring, Christopher; Kitteringham, Neil; Park, Brian K; Nedjadi, Taoufik; Schmid, Michael C; Slupsky, Joseph R; Greenhalf, William; Neoptolemos, John P; Costello, Eithne

    2016-02-01

    The cellular defence protein Nrf2 is a mediator of oncogenesis in pancreatic ductal adenocarcinoma (PDAC) and other cancers. However, the control of Nrf2 expression and activity in cancer is not fully understood. We previously reported the absence of Keap1, a pivotal regulator of Nrf2, in ∼70% of PDAC cases. Here we describe a novel mechanism whereby the epigenetic regulator UHRF1 suppresses Keap1 protein levels. UHRF1 expression was observed in 20% (5 of 25) of benign pancreatic ducts compared to 86% (114 of 132) of pancreatic tumours, and an inverse relationship between UHRF1 and Keap1 levels in PDAC tumours (n = 124) was apparent (p = 0.002). We also provide evidence that UHRF1-mediated regulation of the Nrf2 pathway contributes to the aggressive behaviour of PDAC. Depletion of UHRF1 from PDAC cells decreased growth and enhanced apoptosis and cell cycle arrest. UHRF1 depletion also led to reduced levels of Nrf2-regulated downstream proteins and was accompanied by heightened oxidative stress, in the form of lower glutathione levels and increased reactive oxygen species. Concomitant depletion of Keap1 and UHRF1 restored Nrf2 levels and reversed cell cycle arrest and the increase in reactive oxygen species. Mechanistically, depletion of UHRF1 reduced global and tumour suppressor promoter methylation in pancreatic cancer cell lines, and KEAP1 gene promoter methylation was reduced in one of three cell lines examined. Thus, methylation of the KEAP1 gene promoter may contribute to the suppression of Keap1 protein levels by UHRF1, although our data suggest that additional mechanisms need to be explored. Finally, we demonstrate that K-Ras drives UHRF1 expression, establishing a novel link between this oncogene and Nrf2-mediated cellular protection. Since UHRF1 over-expression occurs in other cancers, its ability to regulate the Keap1-Nrf2 pathway may be critically important to the malignant behaviour of these cancers. PMID:26497117

  10. THE E2/FRB PATHWAY REGULATION OF DNA REPLICATION AND PROTEIN BIOSYNTHESIS

    EPA Science Inventory

    The E2F/Rb pathway plays a pivotal role in the control of cell cycle progression and regulates the expression of genes required for Gl/S transition. Our study examines the genomic response in Drosophila embryos after overexpression and mutation of E2F/Rb pathway molecules. Hierar...