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Sample records for catabolism regulatory protein

  1. Regulatory circuit for responses of nitrogen catabolic gene expression to the GLN3 and DAL80 proteins and nitrogen catabolite repression in Saccharomyces cerevisiae.

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    Daugherty, J R; Rai, R; el Berry, H M; Cooper, T G

    1993-01-01

    We demonstrate that expression of the UGA1, CAN1, GAP1, PUT1, PUT2, PUT4, and DAL4 genes is sensitive to nitrogen catabolite repression. The expression of all these genes, with the exception of UGA1 and PUT2, also required a functional GLN3 protein. In addition, GLN3 protein was required for expression of the DAL1, DAL2, DAL7, GDH1, and GDH2 genes. The UGA1, CAN1, GAP1, and DAL4 genes markedly increased their expression when the DAL80 locus, encoding a negative regulatory element, was disrupted. Expression of the GDH1, PUT1, PUT2, and PUT4 genes also responded to DAL80 disruption, but much more modestly. Expression of GLN1 and GDH2 exhibited parallel responses to the provision of asparagine and glutamine as nitrogen sources but did not follow the regulatory responses noted above for the nitrogen catabolic genes such as DAL5. Steady-state mRNA levels of both genes did not significantly decrease when glutamine was provided as nitrogen source but were lowered by the provision of asparagine. They also did not respond to disruption of DAL80.

  2. Regulatory circuit for responses of nitrogen catabolic gene expression to the GLN3 and DAL80 proteins and nitrogen catabolite repression in Saccharomyces cerevisiae.

    OpenAIRE

    Daugherty, J R; Rai, R; el Berry, H M; Cooper, T. G.

    1993-01-01

    We demonstrate that expression of the UGA1, CAN1, GAP1, PUT1, PUT2, PUT4, and DAL4 genes is sensitive to nitrogen catabolite repression. The expression of all these genes, with the exception of UGA1 and PUT2, also required a functional GLN3 protein. In addition, GLN3 protein was required for expression of the DAL1, DAL2, DAL7, GDH1, and GDH2 genes. The UGA1, CAN1, GAP1, and DAL4 genes markedly increased their expression when the DAL80 locus, encoding a negative regulatory element, was disrupt...

  3. [Biochemical methods for the determination of a clinical protein catabolism].

    Science.gov (United States)

    Roth, E; Funovics, J; Schulz, F; Karner, J

    1980-12-01

    1. 20 patients before surgery received enteral nutrition for three days (12 g nitrogen, 1800 Kcal). Nitrogen and urea excretions in urine during the second and third day were determined. Eleven patients had a negative nitrogen balance (-2,7 and -2,4 g/day). In these patients urea production rates were 21,1 and 20,1 g/day. An urea production rate exceeding 15 g urea/day is probable an indication for a protein catabolism. The reason for this catabolic state seems to be a decreased protein utilisation (49 and 47 percent) as the result of a metabolic stress situation. This metabolic stress was determined according the stress index (Bistrian). The patients were in a stress situation comparable to postoperative stress (+3,7 and +3,9). The determination of urea production rate and catabolic index seems a suitable tool for defining a catabolic state. 2. 3-met-histidine excretion in urine were measured in seven patients postoperatively. In different periods saline or aminoacids solutions (5% alanine) were infused. During alanine administration protein (+49%)--and 3-met-histidine excretions (+50%) increased. It is not possible to state a catabolic situation out of the 3-met-histidine excretion, because an increased excretion may result from a stimulated protein synthesis in muscle tissue or from an increased muscleprotein wasting. 3. Free amino acid pools in plasma and muscle tissue were analysed in patients with severe illness of liver and pancreas. The free amino acid pattern differed from healthy volunteers. In patients with liver disease significantly increased concentrations of phenylalanine, tyrosine and methionine were found. In patients with acute pancreatitis highly abnormal pattern of intracellular amino acids occurred with decreased concentrations of glutamine, cysteine, histidine, lysine, arginine and ornithine. The highly significant decreased concentrations of glutamine (p less than 0,01) indicate a catabolic situation of these patients. A quantification of the

  4. CONSTRUCTION AND ANALYSIS OF IPBR/XYLS HYBRID REGULATORY PROTEINS

    Science.gov (United States)

    IpbR and XylS are related regulatory proteins (having 56% identity). IpbR responds to isopropylbenzene as well as to a variety of hydrophobic chemicals to activate expression of the isopropylbenzene catabolic pathway operon of pRE4 from ipbOP. XylS responds to substituted benzoic...

  5. Changes in substrate utilisation and protein catabolism during multiday cycling in well-trained cyclists.

    Science.gov (United States)

    Oosthuyse, Tanja; Avidon, Ingrid

    2015-01-01

    There is a paucity of studies that have evaluated substrate utilisation and protein catabolism during multiday strenuous exercise in athletes. Eleven well-trained male cyclists completed 3 h of race-simulated cycling on 4 consecutive days. Cyclist exercised 2 h postprandially and with carbohydrate supplementation (~50 g · h(-1)) during exercise. Whole body substrate utilisation was measured by indirect calorimetry, protein catabolism from sweat and urine urea excretion, and blood metabolite concentration was evaluated. Protein catabolism during exercise was significantly greater on days 2-4 (29.9 ± 8.8; 34.0 ± 11.2; 32.0 ± 7.3 g for days 2, 3, and 4, respectively) compared to day 1 (23.3 ± 7.6 g), P catabolism on all successive days.

  6. House sparrows (Passer domesticus) increase protein catabolism in response to water restriction.

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    Gerson, Alexander R; Guglielmo, Christopher G

    2011-04-01

    Birds primarily rely on fat for energy during fasting and to fuel energetically demanding activities. Proteins are catabolized supplemental to fat, the function of which in birds remains poorly understood. It has been proposed that birds may increase the catabolism of body protein under dehydrating conditions as a means to maintain water balance, because catabolism of wet protein yields more total metabolic and bound water (0.155·H(2)O(-1)·kJ(-1)) than wet lipids (0.029 g·H(2)O(-1)·kJ(-1)). On the other hand, protein sparing should be important to maintain function of muscles and organs. We used quantitative magnetic resonance body composition analysis and hygrometry to investigate the effect of water restriction on fat and lean mass catabolism during short-term fasting at rest and in response to a metabolic challenge (4-h shivering) in house sparrows (Passer domesticus). Water loss at rest and during shivering was compared with water gains from the catabolism of tissue. At rest, water-restricted birds had significantly greater lean mass loss, higher plasma uric acid concentration, and plasma osmolality than control birds. Endogenous water gains from lean mass catabolism offset losses over the resting period. Water restriction had no effect on lean mass catabolism during shivering, as water gains from fat oxidation appeared sufficient to maintain water balance. These data provide direct evidence supporting the hypothesis that water stress can increase protein catabolism at rest, possibly as a metabolic strategy to offset high rates of evaporative water loss.

  7. Insulin-like growth factor-I fails to reverse corticosteroid-induced protein catabolism in growing piglets

    NARCIS (Netherlands)

    Hellstern, G; Reijngoud, DJ; Stellaard, F; Okken, A

    1996-01-01

    Corticosteroids such as dexamethasone (DEX) increase leucine turnover and oxidation in humans and animals, indicating whole body protein catabolism. Recently, interest has been growing in the use of recombinant polypeptides such as GH and IGF-I in reversing various states of catabolism. The aim of o

  8. Imbalanced protein expression patterns of anabolic, catabolic, anti-catabolic and inflammatory cytokines in degenerative cervical disc cells: new indications for gene therapeutic treatments of cervical disc diseases.

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    Demissew S Mern

    Full Text Available Degenerative disc disease (DDD of the cervical spine is common after middle age and can cause loss of disc height with painful nerve impingement, bone and joint inflammation. Despite the clinical importance of these problems, in current publications the pathology of cervical disc degeneration has been studied merely from a morphologic view point using magnetic resonance imaging (MRI, without addressing the issue of biological treatment approaches. So far a wide range of endogenously expressed bioactive factors in degenerative cervical disc cells has not yet been investigated, despite its importance for gene therapeutic approaches. Although degenerative lumbar disc cells have been targeted by different biological treatment approaches, the quantities of disc cells and the concentrations of gene therapeutic factors used in animal models differ extremely. These indicate lack of experimentally acquired data regarding disc cell proliferation and levels of target proteins. Therefore, we analysed proliferation and endogenous expression levels of anabolic, catabolic, ant-catabolic, inflammatory cytokines and matrix proteins of degenerative cervical disc cells in three-dimensional cultures. Preoperative MRI grading of cervical discs was used, then grade III and IV nucleus pulposus (NP tissues were isolated from 15 patients, operated due to cervical disc herniation. NP cells were cultured for four weeks with low-glucose in collagen I scaffold. Their proliferation rates were analysed using 3-(4, 5-dimethylthiazolyl-2-2,5-diphenyltetrazolium bromide. Their protein expression levels of 28 therapeutic targets were analysed using enzyme-linked immunosorbent assay. During progressive grades of degeneration NP cell proliferation rates were similar. Significantly decreased aggrecan and collagen II expressions (P<0.0001 were accompanied by accumulations of selective catabolic and inflammatory cytokines (disintegrin and metalloproteinase with thrombospondin motifs 4

  9. Amyloid beta-protein and lipid rafts: focused on biogenesis and catabolism.

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    Araki, Wataru; Tamaoka, Akira

    2015-01-01

    Cerebral accumulation of amyloid β-protein (Aβ) is thought to play a key role in the molecular pathology of Alzheimer's disease (AD). Three secretases (β-, γ-, and α-secretase) are proteases that control the production of Aβ from amyloid precursor protein. Increasing evidence suggests that cholesterol-rich membrane microdomains termed 'lipid rafts' are involved in the biogenesis and accumulation of Aβ as well as Aβ-mediated neurotoxicity. γ-Secretase is enriched in lipid rafts, which are considered an important site for Aβ generation. Additionally, Aβ-degrading peptidases located in lipid rafts, such as neprilysin, appear to play a role in Aβ catabolism. This mini-review focuses on the roles of lipid rafts in the biogenesis and catabolism of Aβ, covering recent research on the relationship between lipid rafts and the three secretases or Aβ-degrading peptidases. Furthermore, the significance of lipid rafts in Aβ aggregation and neurotoxicity is briefly summarized.

  10. DETERMINATION OF PROTEIN CATABOLIC RATE IN PATIENTS ON CHRONIC INTERMITTENT HEMODIALYSIS - UREA OUTPUT MEASUREMENTS COMPARED WITH DIETARY-PROTEIN INTAKE AND WITH CALCULATION OF UREA GENERATION RATE

    NARCIS (Netherlands)

    STEGEMAN, CA; HUISMAN, RM; DEROUW, B; JOOSTEMA, A; DEJONG, PE

    1995-01-01

    We assessed the agreement between different methods of determining protein catabolic rate (PCR) in hemodialysis patients and the possible influence of postdialysis urea rebound and the length of the interdialytic interval on the PCR determination. Protein catabolic rate derived from measured total u

  11. Catabolic and regulatory systems in Shewanella oneidensis MR-1 involved in electricity generation in microbial fuel cells

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    Atsushi eKouzuma

    2015-06-01

    Full Text Available Shewanella oneidensis MR-1 is a facultative anaerobe that respires using a variety of inorganic and organic compounds. MR-1 is also capable of utilizing extracellular solid materials, including anodes in microbial fuel cells (MFCs, as electron acceptors, thereby enabling electricity generation. As MFCs have the potential to generate electricity from biomass waste and wastewater, MR-1 has been extensively studied to identify the molecular systems that are involved in electricity generation in MFCs. These studies have demonstrated the importance of extracellular electron-transfer pathways that electrically connect the quinone pool in the cytoplasmic membrane to extracellular electron acceptors. Electricity generation is also dependent on intracellular catabolic pathways that oxidize electron donors, such as lactate, and regulatory systems that control the expression of genes encoding the components of catabolic and electron-transfer pathways. In addition, recent findings suggest that cell-surface polymers, e.g., exopolysaccharides, and secreted chemicals, which function as electron shuttles, are also involved in electricity generation. Despite these advances in our knowledge on the extracellular electron-transfer processes in MR-1, further efforts are necessary to fully understand the underlying intra- and extra-cellular molecular systems for electricity generation in MFCs. We suggest that investigating how MR-1 coordinates these systems to efficiently transfer electrons to electrodes and conserve electrochemical energy for cell proliferation is important for establishing the biological bases for MFCs.

  12. Membrane lipids regulate ganglioside GM2 catabolism and GM2 activator protein activity.

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    Anheuser, Susi; Breiden, Bernadette; Schwarzmann, Günter; Sandhoff, Konrad

    2015-09-01

    Ganglioside GM2 is the major lysosomal storage compound of Tay-Sachs disease. It also accumulates in Niemann-Pick disease types A and B with primary storage of SM and with cholesterol in type C. Reconstitution of GM2 catabolism with β-hexosaminidase A and GM2 activator protein (GM2AP) at uncharged liposomal surfaces carrying GM2 as substrate generated only a physiologically irrelevant catabolic rate, even at pH 4.2. However, incorporation of anionic phospholipids into the GM2 carrying liposomes stimulated GM2 hydrolysis more than 10-fold, while the incorporation of plasma membrane stabilizing lipids (SM and cholesterol) generated a strong inhibition of GM2 hydrolysis, even in the presence of anionic phospholipids. Mobilization of membrane lipids by GM2AP was also inhibited in the presence of cholesterol or SM, as revealed by surface plasmon resonance studies. These lipids also reduced the interliposomal transfer rate of 2-NBD-GM1 by GM2AP, as observed in assays using Förster resonance energy transfer. Our data raise major concerns about the usage of recombinant His-tagged GM2AP compared with untagged protein. The former binds more strongly to anionic GM2-carrying liposomal surfaces, increases GM2 hydrolysis, and accelerates intermembrane transfer of 2-NBD-GM1, but does not mobilize membrane lipids.

  13. Membrane lipids regulate ganglioside GM2 catabolism and GM2 activator protein activity[S

    Science.gov (United States)

    Anheuser, Susi; Breiden, Bernadette; Schwarzmann, Günter; Sandhoff, Konrad

    2015-01-01

    Ganglioside GM2 is the major lysosomal storage compound of Tay-Sachs disease. It also accumulates in Niemann-Pick disease types A and B with primary storage of SM and with cholesterol in type C. Reconstitution of GM2 catabolism with β-hexosaminidase A and GM2 activator protein (GM2AP) at uncharged liposomal surfaces carrying GM2 as substrate generated only a physiologically irrelevant catabolic rate, even at pH 4.2. However, incorporation of anionic phospholipids into the GM2 carrying liposomes stimulated GM2 hydrolysis more than 10-fold, while the incorporation of plasma membrane stabilizing lipids (SM and cholesterol) generated a strong inhibition of GM2 hydrolysis, even in the presence of anionic phospholipids. Mobilization of membrane lipids by GM2AP was also inhibited in the presence of cholesterol or SM, as revealed by surface plasmon resonance studies. These lipids also reduced the interliposomal transfer rate of 2-NBD-GM1 by GM2AP, as observed in assays using Förster resonance energy transfer. Our data raise major concerns about the usage of recombinant His-tagged GM2AP compared with untagged protein. The former binds more strongly to anionic GM2-carrying liposomal surfaces, increases GM2 hydrolysis, and accelerates intermembrane transfer of 2-NBD-GM1, but does not mobilize membrane lipids. PMID:26175473

  14. Argininosuccinate synthetase regulates hepatic AMPK linking protein catabolism and ureagenesis to hepatic lipid metabolism.

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    Madiraju, Anila K; Alves, Tiago; Zhao, Xiaojian; Cline, Gary W; Zhang, Dongyan; Bhanot, Sanjay; Samuel, Varman T; Kibbey, Richard G; Shulman, Gerald I

    2016-06-14

    A key sensor of cellular energy status, AMP-activated protein kinase (AMPK), interacts allosterically with AMP to maintain an active state. When active, AMPK triggers a metabolic switch, decreasing the activity of anabolic pathways and enhancing catabolic processes such as lipid oxidation to restore the energy balance. Unlike oxidative tissues, in which AMP is generated from adenylate kinase during states of high energy demand, the ornithine cycle enzyme argininosuccinate synthetase (ASS) is a principle site of AMP generation in the liver. Here we show that ASS regulates hepatic AMPK, revealing a central role for ureagenesis flux in the regulation of metabolism via AMPK. Treatment of primary rat hepatocytes with amino acids increased gluconeogenesis and ureagenesis and, despite nutrient excess, induced both AMPK and acetyl-CoA carboxylase (ACC) phosphorylation. Antisense oligonucleotide knockdown of hepatic ASS1 expression in vivo decreased liver AMPK activation, phosphorylation of ACC, and plasma β-hydroxybutyrate concentrations. Taken together these studies demonstrate that increased amino acid flux can activate AMPK through increased AMP generated by ASS, thus providing a novel link between protein catabolism, ureagenesis, and hepatic lipid metabolism.

  15. Role of Myofibrillar Protein Catabolism in Development of Glucocorticoid Myopathy: Aging and Functional Activity Aspects

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    Teet Seene

    2016-05-01

    Full Text Available Muscle weakness in corticosteroid myopathy is mainly the result of the destruction and atrophy of the myofibrillar compartment of fast-twitch muscle fibers. Decrease of titin and myosin, and the ratio of nebulin and MyHC in myopathic muscle, shows that these changes of contractile and elastic proteins are the result of increased catabolism of the abovementioned proteins in skeletal muscle. Slow regeneration of skeletal muscle is in good correlation with a decreased number of satellite cells under the basal lamina of muscle fibers. Aging causes a reduction of AMP-activated protein kinase (AMPK activity as the result of the reduced function of the mitochondrial compartment. AMPK activity increases as a result of increased functional activity. Resistance exercise causes anabolic and anticatabolic effects in skeletal muscle: muscle fibers experience hypertrophy while higher myofibrillar proteins turn over. These changes are leading to the qualitative remodeling of muscle fibers. As a result of these changes, possible maximal muscle strength is increasing. Endurance exercise improves capillary blood supply, increases mitochondrial biogenesis and muscle oxidative capacity, and causes a faster turnover rate of sarcoplasmic proteins as well as qualitative remodeling of type I and IIA muscle fibers. The combination of resistance and endurance exercise may be the fastest way to prevent or decelerate muscle atrophy due to the anabolic and anticatabolic effects of exercise combined with an increase in oxidative capacity. The aim of the present short review is to assess the role of myofibrillar protein catabolism in the development of glucocorticoid-caused myopathy from aging and physical activity aspects.

  16. Role of Myofibrillar Protein Catabolism in Development of Glucocorticoid Myopathy: Aging and Functional Activity Aspects.

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    Seene, Teet; Kaasik, Priit

    2016-05-13

    Muscle weakness in corticosteroid myopathy is mainly the result of the destruction and atrophy of the myofibrillar compartment of fast-twitch muscle fibers. Decrease of titin and myosin, and the ratio of nebulin and MyHC in myopathic muscle, shows that these changes of contractile and elastic proteins are the result of increased catabolism of the abovementioned proteins in skeletal muscle. Slow regeneration of skeletal muscle is in good correlation with a decreased number of satellite cells under the basal lamina of muscle fibers. Aging causes a reduction of AMP-activated protein kinase (AMPK) activity as the result of the reduced function of the mitochondrial compartment. AMPK activity increases as a result of increased functional activity. Resistance exercise causes anabolic and anticatabolic effects in skeletal muscle: muscle fibers experience hypertrophy while higher myofibrillar proteins turn over. These changes are leading to the qualitative remodeling of muscle fibers. As a result of these changes, possible maximal muscle strength is increasing. Endurance exercise improves capillary blood supply, increases mitochondrial biogenesis and muscle oxidative capacity, and causes a faster turnover rate of sarcoplasmic proteins as well as qualitative remodeling of type I and IIA muscle fibers. The combination of resistance and endurance exercise may be the fastest way to prevent or decelerate muscle atrophy due to the anabolic and anticatabolic effects of exercise combined with an increase in oxidative capacity. The aim of the present short review is to assess the role of myofibrillar protein catabolism in the development of glucocorticoid-caused myopathy from aging and physical activity aspects.

  17. Influence of black gram (Vigna mungo) trypsin inhibitory fraction on the hepatic protein catabolism in male albino mice.

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    Kamalakannan, V; Sathyamoorthy, A V; Motlag, D B

    1984-01-01

    The effect of black gram and black gram trypsin inhibitor on the protein catabolism of male albino mice has been investigated. Group 1 was given autoclaved black gram (control), Group II raw black gram and Group III the autoclaved black gram incorporated with 1% black gram trypsin inhibitor. Blood as well as urinary urea and creatine were found to be elevated in Groups II and III. Increased levels of arginase, ornithine transcarbamylase and transaminases were noted in Groups II and III. The results suggested an enhanced catabolism of proteins evoked by the native black gram trypsin inhibitor.

  18. [Protein catabolism and malnutrition in liver cirrhosis - impact of oral nutritional therapy].

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    Norman, K; Valentini, L; Lochs, H; Pirlich, M

    2010-07-01

    Malnutrition with loss of muscle is common in patients with liver cirrhosis and has negative impact on morbidity and mortality. The aetiology of malnutrition is multifactorial and includes inflammation, early onset of gluconeogenesis due to impaired glycogen storage and sometimes hypermetabolism. Reduced nutritional intake, however, plays the most important role in the pathogenesis of malnutrition. There is, however, ample evidence that nutritional intake and therapy are inadequate in liver cirrhosis although studies have clearly shown that dietary counselling and nutritional therapy with oral supplements improve intake in these patients. Protein requirement is considered to be increased in liver cirrhosis and high protein intake has been shown to be well tolerated and associated with an improvement of liver function and nutritional status. Protein intolerance on the other hand is uncommon and hepatic encephalopathy can thus rarely be attributed to high protein consumption. Recommendations for general protein restriction must therefore be considered obsolete and rather a risk factor for an impaired clinical outcome. Furthermore, the administration of late evening meals is highly beneficial in patients with liver disease since the rapid onset of the overnight catabolic state is counteracted. The serum concentration of branched-chain amino acids (BCAA) is decreased in patients with liver cirrhosis and long-term supplementation of BCAA has been shown to improve nutritional status and prolong event-free survival and quality of life.

  19. Seasonal dynamics of flight muscle fatty acid binding protein and catabolic enzymes in a migratory shorebird.

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    Guglielmo, Christopher G; Haunerland, Norbert H; Hochachka, Peter W; Williams, Tony D

    2002-05-01

    We developed an ELISA to measure heart-type fatty acid binding protein (H-FABP) in muscles of the western sandpiper (Calidris mauri), a long-distance migrant shorebird. H-FABP accounted for almost 11% of cytosolic protein in the heart. Pectoralis H-FABP levels were highest during migration (10%) and declined to 6% in tropically wintering female sandpipers. Premigratory birds increased body fat, but not pectoralis H-FABP, indicating that endurance flight training may be required to stimulate H-FABP expression. Juveniles making their first migration had lower pectoralis H-FABP than adults, further supporting a role for flight training. Aerobic capacity, measured by citrate synthase activity, and fatty acid oxidation capacity, measured by 3-hydroxyacyl-CoA-dehydrogenase and carnitine palmitoyl transferase activities, did not change during premigration but increased during migration by 6, 12, and 13%, respectively. The greater relative induction of H-FABP (+70%) with migration than of catabolic enzymes suggests that elevated H-FABP is related to the enhancement of uptake of fatty acids from the circulation. Citrate synthase, 3-hydroxyacyl-CoA-dehydrogenase, and carnitine palmitoyl transferase were positively correlated within individuals, suggesting coexpression, but enzyme activities were unrelated to H-FABP levels.

  20. Vitamin A deficiency increases protein catabolism and induces urea cycle enzymes in rats.

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    Esteban-Pretel, Guillermo; Marín, M Pilar; Cabezuelo, Francisco; Moreno, Verónica; Renau-Piqueras, Jaime; Timoneda, Joaquín; Barber, Teresa

    2010-04-01

    Chronic vitamin A deficiency induces a substantial delay in the rates of weight and height gain in both humans and experimental animals. This effect has been associated with an impaired nutrient metabolism and loss of body protein. Therefore, we analyzed the effect of vitamin A deficiency on endogenous proteolysis and nitrogen metabolism and its reversibility with all-trans retinoic acid (RA). Male weanling rats, housed in pairs, were pair-fed a vitamin A-deficient (VAD) or control diet until they were 60 d old. A group of deficient rats were further treated with daily intraperitoneal injections of all-trans RA for 10 d. Final body and tissue (i.e. liver and heart) weights were significantly lower and tissue:body weight ratios were similar in VAD rats and in controls. Conversely, the epididymal white fat:body weight ratio and the plasma concentrations of alanine aminotransferase and adiponectin were significantly higher in VAD rats, which also had hepatic macrovesicular lipid accumulations. Plasma and gastrocnemius muscle 3-methylhistidine, urine nitrogen, and plasma and urine urea concentrations were all significantly higher in the VAD group. The expression of the genes encoding urea cycle enzymes and their activities increased in VAD livers. These changes were partially reverted by all-trans RA. We propose that fuel partitioning in vitamin A deficiency may shift from fatty acids to protein catabolism as an energy source. Our results emphasize the importance of vitamin A on the energy balance control system and they provide an explanation for the role of vitamin A in protein turnover, development, and growth.

  1. Regulation of glutamate dehydrogenase activity in relation to carbon limitation and protein catabolism in carrot cell suspension cultures.

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    Robinson, S A; Stewart, G R; Phillips, R

    1992-03-01

    Glutamate dehydrogenase (GDH) specific activity and function have been studied in cell suspension cultures of carrot (Daucus carota L. cv Chantenay) in response to carbon and nitrogen supply in the culture medium. The specific activity of GDH was derepressed in sucrose-starved cells concomitant with protein catabolism, ammonium excretion, and the accumulation of metabolically active amino acids. The addition of sucrose led to a rapid decrease in GDH specific activity, an uptake of ammonium from the medium, and a decrease in amino acid levels. The extent of GDH derepression was correlated positively with cellular glutamate concentration. These findings strengthen the view that the function of GDH is the catabolism of glutamate, which under conditions of carbon stress provides carbon skeletons for tricarboxylic acid cycle activity.

  2. Magnolol Affects Cellular Proliferation, Polyamine Biosynthesis and Catabolism-Linked Protein Expression and Associated Cellular Signaling Pathways in Human Prostate Cancer Cells in vitro

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    Brendan T. McKeown

    2015-01-01

    Full Text Available Background: Prostate cancer is the most commonly diagnosed form of cancer in men in Canada and the United States. Both genetic and environmental factors contribute to the development and progression of many cancers, including prostate cancer. Context and purpose of this study: This study investigated the effects of magnolol, a compound found in the roots and bark of the magnolia tree Magnolia officinalis, on cellular proliferation and proliferation-linked activities of PC3 human prostate cancer cells in vitro. Results: PC3 cells exposed to magnolol at a concentration of 80 μM for 6 hours exhibited decreased protein expression of ornithine decarboxylase, a key regulator in polyamine biosynthesis, as well as affecting the expression of other proteins involved in polyamine biosynthesis and catabolism. Furthermore, protein expression of the R2 subunit of ribonucleotide reductase, a key regulatory protein associated with DNA synthesis, was significantly decreased. Finally, the MAPK (mitogen-activated protein kinase, PI3K (phosphatidylinositol 3-kinase, NFκB (nuclear factor of kappa-light-chain-enhancer of activated B cells and AP-1 (activator protein 1 cellular signaling pathways were assayed to determine which, if any, of these pathways magnolol exposure would alter. Protein expressions of p-JNK-1 and c-jun were significantly increased while p-p38, JNK-1/2, PI3Kp85, p-PI3Kp85, p-Akt, NFκBp65, p-IκBα and IκBα protein expressions were significantly decreased. Conclusions: These alterations further support the anti-proliferative effects of magnolol on PC3 human prostate cancer cells in vitro and suggest that magnolol may have potential as a novel anti-prostate cancer agent.

  3. Ectoine-induced proteins in Sinorhizobium meliloti include an Ectoine ABC-type transporter involved in osmoprotection and ectoine catabolism.

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    Jebbar, Mohamed; Sohn-Bösser, Linda; Bremer, Erhard; Bernard, Théophile; Blanco, Carlos

    2005-02-01

    To understand the mechanisms of ectoine-induced osmoprotection in Sinorhizobium meliloti, a proteomic examination of S. meliloti cells grown in minimal medium supplemented with ectoine was undertaken. This revealed the induction of 10 proteins. The protein products of eight genes were identified by using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry. Five of these genes, with four other genes whose products were not detected on two-dimensional gels, belong to the same gene cluster, which is localized on the pSymB megaplasmid. Four of the nine genes encode the characteristic components of an ATP-binding cassette transporter that was named ehu, for ectoine/hydroxyectoine uptake. This transporter was encoded by four genes (ehuA, ehuB, ehuC, and ehuD) that formed an operon with another gene cluster that contains five genes, named eutABCDE for ectoine utilization. On the basis of sequence homologies, eutABCDE encode enzymes with putative and hypothetical functions in ectoine catabolism. Analysis of the properties of ehuA and eutA mutants suggests that S. meliloti possesses at least one additional ectoine catabolic pathway as well as a lower-affinity transport system for ectoine and hydroxyectoine. The expression of ehuB, as determined by measurements of UidA activity, was shown to be induced by ectoine and hydroxyectoine but not by glycine betaine or by high osmolality.

  4. The ygeW encoded protein from Escherichia coli is a knotted ancestral catabolic transcarbamylase

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yongdong; Jin, Zhongmin; Yu, Xiaolin; Allewell, Norma M.; Tuchman, Mendel; Shi, Dashuang (Maryland); (GWU); (Georgia)

    2012-06-28

    Purine degradation plays an essential role in nitrogen metabolism in most organisms. Uric acid is the final product of purine catabolism in humans, anthropoid apes, birds, uricotelic reptiles, and almost all insects. Elevated levels of uric acid in blood (hyperuricemia) cause human diseases such as gout, kidney stones, and renal failure. Although no enzyme has been identified that further degrades uric acid in humans, it can be oxidized to produce allantoin by free-radical attack. Indeed, elevated levels of allantoin are found in patients with rheumatoid arthritis, chronic lung disease, bacterial meningitis, and noninsulin-dependent diabetes mellitus. In other mammals, some insects and gastropods, uric acid is enzymatically degraded to the more soluble allantoin through the sequential action of three enzymes: urate oxidase, 5-hydroxyisourate (HIU) hydrolase and 2-oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline (OHCU) decarboxylase. Therefore, an elective treatment for acute hyperuricemia is the administration of urate oxidase. Many organisms, including plants, some fungi and several bacteria, are able to catabolize allantoin to release nitrogen, carbon, and energy. In Arabidopsis thaliana and Eschrichia coli, S-allantoin has recently been shown to be degraded to glycolate and urea by four enzymes: allantoinase, allantoate amidohydrolase, ureidoglycine aminohydrolase, and ureidoglycolate amidohydrolase.

  5. Regulation of muscle protein synthesis and the effects of catabolic states.

    Science.gov (United States)

    Gordon, Bradley S; Kelleher, Andrew R; Kimball, Scot R

    2013-10-01

    Protein synthesis and degradation are dynamically regulated processes that act in concert to control the accretion or loss of muscle mass. The present article focuses on the mechanisms involved in the impairment of protein synthesis that are associated with skeletal muscle atrophy. The vast majority of mechanisms known to regulate protein synthesis involve modulation of the initiation phase of mRNA translation, which comprises a series of reactions that result in the binding of initiator methionyl-tRNAi and mRNA to the 40S ribosomal subunit. The function of the proteins involved in both events has been shown to be repressed under atrophic conditions such as sepsis, cachexia, chronic kidney disease, sarcopenia, and disuse atrophy. The basis for the inhibition of protein synthesis under such conditions is likely to be multifactorial and includes insulin/insulin-like growth factor 1 resistance, pro-inflammatory cytokine expression, malnutrition, corticosteroids, and/or physical inactivity. The present article provides an overview of the existing literature regarding mechanisms and signaling pathways involved in the regulation of mRNA translation as they apply to skeletal muscle wasting, as well as the efficacy of potential clinical interventions such as nutrition and exercise in the maintenance of skeletal muscle protein synthesis under atrophic conditions. This article is part of a Directed Issue entitled: Molecular basis of muscle wasting.

  6. Polyamine catabolism and disease.

    Science.gov (United States)

    Casero, Robert A; Pegg, Anthony E

    2009-07-15

    In addition to polyamine homoeostasis, it has become increasingly clear that polyamine catabolism can play a dominant role in drug response, apoptosis and the response to stressful stimuli, and contribute to the aetiology of several pathological states, including cancer. The highly inducible enzymes SSAT (spermidine/spermine N1-acetyltransferase) and SMO (spermine oxidase) and the generally constitutively expressed APAO (N1-acetylpolyamine oxidase) appear to play critical roles in many normal and disease processes. The dysregulation of polyamine catabolism frequently accompanies several disease states and suggests that such dysregulation may both provide useful insight into disease mechanism and provide unique druggable targets that can be exploited for therapeutic benefit. Each of these enzymes has the potential to alter polyamine homoeostasis in response to multiple cell signals and the two oxidases produce the reactive oxygen species H2O2 and aldehydes, each with the potential to produce pathological states. The activity of SSAT provides substrates for APAO or substrates for the polyamine exporter, thus reducing the intracellular polyamine concentration, the net effect of which depends on the magnitude and rate of any increase in SSAT. SSAT may also influence cellular metabolism via interaction with other proteins and by perturbing the content of acetyl-CoA and ATP. The goal of the present review is to cover those aspects of polyamine catabolism that have an impact on disease aetiology or treatment and to provide a solid background in this ever more exciting aspect of polyamine biology.

  7. Regulatory mechanisms of skeletal muscle protein turnover during exercise

    DEFF Research Database (Denmark)

    Rose, Adam John; Richter, Erik

    2009-01-01

    Skeletal muscle protein turnover is a relatively slow metabolic process that is altered by various physiological stimuli such as feeding/fasting and exercise. During exercise, catabolism of amino acids contributes very little to ATP turnover in working muscle. With regards to protein turnover......, there is now consistent data from tracer studies in rodents and humans showing that global protein synthesis is blunted in working skeletal muscle. Whether there is altered skeletal muscle protein breakdown during exercise remains unclear. The blunting of protein synthesis is believed to be mediated...... downstream of changes in intracellular Ca(2+) and energy turnover. In particular, a signaling cascade involving Ca(2+)-calmodulin-eEF2 kinase-eEF2 is implicated. The possible functional significance of altered protein turnover in working skeletal muscle during exercise is discussed. Further work...

  8. Plant Antifreeze Proteins and Their Expression Regulatory Mechanism

    Institute of Scientific and Technical Information of China (English)

    Lin Yuan-zhen; Lin Shan-zhi; Zhang Zhi-yi; Zhang Wei; Liu Wen-feng

    2005-01-01

    Low temperature is one of the major limiting environmental factors which constitutes the growth, development,productivity and distribution of plants. Over the past several years, the proteins and genes associated with freezing resistance of plants have been widely studied. The recent progress of domestic and foreign research on plant antifreeze proteins and the identification and characterization of plant antifreeze protein genes, especially on expression regulatory mechanism of plant antifreeze proteins are reviewed in this paper. Finally, some unsolved problems and the trend of research in physiological functions and gene expression regulatory mechanism of plant antifreeze proteins are discussed.

  9. Phenylalanine induces Burkholderia cenocepacia phenylacetic acid catabolism through degradation to phenylacetyl-CoA in synthetic cystic fibrosis sputum medium.

    Science.gov (United States)

    Yudistira, Harry; McClarty, Leigh; Bloodworth, Ruhi A M; Hammond, Sydney A; Butcher, Haley; Mark, Brian L; Cardona, Silvia T

    2011-09-01

    Synthetic cystic fibrosis sputum medium (SCFM) is rich in amino acids and supports robust growth of Burkholderia cenocepacia, a member of the Burkholderia cepacia complex (Bcc). Previous work demonstrated that B. cenocepacia phenylacetic acid (PA) catabolic genes are up-regulated during growth in SCFM and are required for full virulence in a Caenorhabditis elegans host model. In this work, we investigated the role of phenylalanine, one of the aromatic amino acids present in SCFM, as an inducer of the PA catabolic pathway. Phenylalanine degradation intermediates were used as sole carbon sources for growth and gene reporter experiments. In addition to phenylalanine and PA, phenylethylamine, phenylpyruvate, and 2-phenylacetamide were usable as sole carbon sources by wild type B. cenocepacia K56-2, but not by a PA catabolism-defective mutant. EMSA analysis showed that the binding of PaaR, the negative regulator protein of B. cenocepacia PA catabolism, to PA regulatory DNA could only be relieved by phenylacetyl-Coenzyme A (PA-CoA), but not by any of the putative phenylalanine degradation intermediates. Taken together, our results show that in B. cenocepacia, phenylalanine is catabolized to PA and induces PA catabolism through PA activation to PA-CoA. Thus, PaaR shares the same inducer with PaaX, the regulator of PA catabolism in Escherichia coli, despite belonging to a different protein family.

  10. Combination of recreational soccer and caloric restricted diet reduces markers of protein catabolism and cardiovascular risk in patients with type 2 diabetes

    DEFF Research Database (Denmark)

    de Sousa, M Vieira; Fukui, R; Krustrup, Peter

    2017-01-01

    Background: Moderate calorie-restricted diets and exercise training prevent loss of lean mass and cardiovascular risk. Because adherence to routine exercise recommendation is generally poor, we utilized recreational soccer training as a novel therapeutic exercise intervention in type 2 diabetes (T2......D) patients. Objective: We compared the effects of acute and chronic soccer training plus calorie-restricted diet on protein catabolism and cardiovascular risk markers in T2D. Design, setting and subjects: Fifty-one T2D patients (61.1±6.4 years, 29 females: 22 males) were randomly allocated...

  11. Modifier effects between regulatory and protein-coding variation.

    Directory of Open Access Journals (Sweden)

    Antigone S Dimas

    2008-10-01

    Full Text Available Genome-wide associations have shown a lot of promise in dissecting the genetics of complex traits in humans with single variants, yet a large fraction of the genetic effects is still unaccounted for. Analyzing genetic interactions between variants (epistasis is one of the potential ways forward. We investigated the abundance and functional impact of a specific type of epistasis, namely the interaction between regulatory and protein-coding variants. Using genotype and gene expression data from the 210 unrelated individuals of the original four HapMap populations, we have explored the combined effects of regulatory and protein-coding single nucleotide polymorphisms (SNPs. We predict that about 18% (1,502 out of 8,233 nsSNPs of protein-coding variants are differentially expressed among individuals and demonstrate that regulatory variants can modify the functional effect of a coding variant in cis. Furthermore, we show that such interactions in cis can affect the expression of downstream targets of the gene containing the protein-coding SNP. In this way, a cis interaction between regulatory and protein-coding variants has a trans impact on gene expression. Given the abundance of both types of variants in human populations, we propose that joint consideration of regulatory and protein-coding variants may reveal additional genetic effects underlying complex traits and disease and may shed light on causes of differential penetrance of known disease variants.

  12. Modifier effects between regulatory and protein-coding variation.

    Science.gov (United States)

    Dimas, Antigone S; Stranger, Barbara E; Beazley, Claude; Finn, Robert D; Ingle, Catherine E; Forrest, Matthew S; Ritchie, Matthew E; Deloukas, Panos; Tavaré, Simon; Dermitzakis, Emmanouil T

    2008-10-01

    Genome-wide associations have shown a lot of promise in dissecting the genetics of complex traits in humans with single variants, yet a large fraction of the genetic effects is still unaccounted for. Analyzing genetic interactions between variants (epistasis) is one of the potential ways forward. We investigated the abundance and functional impact of a specific type of epistasis, namely the interaction between regulatory and protein-coding variants. Using genotype and gene expression data from the 210 unrelated individuals of the original four HapMap populations, we have explored the combined effects of regulatory and protein-coding single nucleotide polymorphisms (SNPs). We predict that about 18% (1,502 out of 8,233 nsSNPs) of protein-coding variants are differentially expressed among individuals and demonstrate that regulatory variants can modify the functional effect of a coding variant in cis. Furthermore, we show that such interactions in cis can affect the expression of downstream targets of the gene containing the protein-coding SNP. In this way, a cis interaction between regulatory and protein-coding variants has a trans impact on gene expression. Given the abundance of both types of variants in human populations, we propose that joint consideration of regulatory and protein-coding variants may reveal additional genetic effects underlying complex traits and disease and may shed light on causes of differential penetrance of known disease variants.

  13. The mitochondrial sulfur dioxygenase ETHYLMALONIC ENCEPHALOPATHY PROTEIN1 is required for amino acid catabolism during carbohydrate starvation and embryo development in Arabidopsis.

    Science.gov (United States)

    Krüßel, Lena; Junemann, Johannes; Wirtz, Markus; Birke, Hannah; Thornton, Jeremy D; Browning, Luke W; Poschet, Gernot; Hell, Rüdiger; Balk, Janneke; Braun, Hans-Peter; Hildebrandt, Tatjana M

    2014-05-01

    The sulfur dioxygenase ETHYLMALONIC ENCEPHALOPATHY PROTEIN1 (ETHE1) catalyzes the oxidation of persulfides in the mitochondrial matrix and is essential for early embryo development in Arabidopsis (Arabidopsis thaliana). We investigated the biochemical and physiological functions of ETHE1 in plant metabolism using recombinant Arabidopsis ETHE1 and three transfer DNA insertion lines with 50% to 99% decreased sulfur dioxygenase activity. Our results identified a new mitochondrial pathway catalyzing the detoxification of reduced sulfur species derived from cysteine catabolism by oxidation to thiosulfate. Knockdown of the sulfur dioxygenase impaired embryo development and produced phenotypes of starvation-induced chlorosis during short-day growth conditions and extended darkness, indicating that ETHE1 has a key function in situations of high protein turnover, such as seed production and the use of amino acids as alternative respiratory substrates during carbohydrate starvation. The amino acid profile of mutant plants was similar to that caused by defects in the electron-transfer flavoprotein/electron-transfer flavoprotein:ubiquinone oxidoreductase complex and associated dehydrogenases. Thus, in addition to sulfur amino acid catabolism, ETHE1 also affects the oxidation of branched-chain amino acids and lysine.

  14. Understanding Sugar Catabolism in Unicellular Cyanobacteria Toward the Application in Biofuel and Biomaterial Production.

    Science.gov (United States)

    Osanai, Takashi; Iijima, Hiroko; Hirai, Masami Yokota

    2016-01-01

    Synechocystis sp. PCC 6803 is a model species of the cyanobacteria that undergo oxygenic photosynthesis, and has garnered much attention for its potential biotechnological applications. The regulatory mechanism of sugar metabolism in this cyanobacterium has been intensively studied and recent omics approaches have revealed the changes in transcripts, proteins, and metabolites of sugar catabolism under different light and nutrient conditions. Several transcriptional regulators that control the gene expression of enzymes related to sugar catabolism have been identified in the past 10 years, including a sigma factor, transcription factors, and histidine kinases. The modification of these genes can lead to alterations in the primary metabolism as well as the levels of high-value products such as bioplastics and hydrogen. This review summarizes recent studies on sugar catabolism in Synechocystis sp. PCC 6803, emphasizing the importance of elucidating the molecular mechanisms of cyanobacterial metabolism for biotechnological applications.

  15. Functional Classification of Immune Regulatory Proteins

    Energy Technology Data Exchange (ETDEWEB)

    Rubinstein, Rotem [Albert Einstein College of Medicine, Bronx, NY (United States); Ramagopal, Udupi A. [Albert Einstein College of Medicine, Bronx, NY (United States); Nathenson, Stanley G. [Albert Einstein College of Medicine, Bronx, NY (United States); Almo, Steven C. [Albert Einstein College of Medicine, Bronx, NY (United States); Fiser, Andras [Albert Einstein College of Medicine, Bronx, NY (United States)

    2013-05-01

    Members of the immunoglobulin superfamily (IgSF) control innate and adaptive immunity and are prime targets for the treatment of autoimmune diseases, infectious diseases, and malignancies. We describe a computational method, termed the Brotherhood algorithm, which utilizes intermediate sequence information to classify proteins into functionally related families. This approach identifies functional relationships within the IgSF and predicts additional receptor-ligand interactions. As a specific example, we examine the nectin/nectin-like family of cell adhesion and signaling proteins and propose receptor-ligand interactions within this family. We were guided by the Brotherhood approach and present the high-resolution structural characterization of a homophilic interaction involving the class-I MHC-restricted T-cell-associated molecule, which we now classify as a nectin-like family member. The Brotherhood algorithm is likely to have a significant impact on structural immunology by identifying those proteins and complexes for which structural characterization will be particularly informative.

  16. Sumoylation: a regulatory protein modification in health and disease.

    Science.gov (United States)

    Flotho, Annette; Melchior, Frauke

    2013-01-01

    Posttranslational modification with small ubiquitin-related modifier (SUMO) proteins is now established as one of the key regulatory protein modifications in eukaryotic cells. Hundreds of proteins involved in processes such as chromatin organization, transcription, DNA repair, macromolecular assembly, protein homeostasis, trafficking, and signal transduction are subject to reversible sumoylation. Hence, it is not surprising that disease links are beginning to emerge and that interference with sumoylation is being considered for intervention. Here, we summarize basic mechanisms and highlight recent developments in the physiology of sumoylation.

  17. Plant villins:Versatile actin regulatory proteins

    Institute of Scientific and Technical Information of China (English)

    Shanjin Huang; Xiaolu Qu; Ruihui Zhang

    2015-01-01

    Regulation of actin dynamics is a central theme in cel biology that is important for different aspects of cel physiology. Vil in, a member of the vil in/gelsolin/fragmin superfamily of proteins, is an important regulator of actin. Vil ins contain six gelsolin homology domains (G1–G6) and an extra headpiece domain. In contrast to their mammalian counterparts, plant vil ins are expressed widely, implying that plant vil ins play a more general role in regulating actin dynamics. Some plant vil ins have a defined role in modifying actin dynamics in the pol en tube;most of their in vivo activities remain to be ascertained. Recently, our understanding of the functions and mechanisms of action for plant vil ins has progressed rapidly, primarily due to the advent of Arabidopsis thaliana genetic approaches and imaging capabilities that can visualize actin dynamics at the single filament level in vitro and in living plant cel s. In this review, we focus on discussing the biochemical activities and modes of regulation of plant vil ins. Here, we present current understand-ing of the functions of plant vil ins. Final y, we highlight some of the key unanswered questions regarding the functions and regulation of plant vil ins for future research.

  18. Dynamical Analysis of Protein Regulatory Network in Budding Yeast Nucleus

    Institute of Scientific and Technical Information of China (English)

    LI Fang-Ting; JIA Xun

    2006-01-01

    @@ Recent progresses in the protein regulatory network of budding yeast Saccharomyces cerevisiae have provided a global picture of its protein network for further dynamical research. We simplify and modularize the protein regulatory networks in yeast nucleus, and study the dynamical properties of the core 37-node network by a Boolean network model, especially the evolution steps and final fixed points. Our simulation results show that the number of fixed points N(k) for a given size of the attraction basin k obeys a power-law distribution N(k)∝k-2.024. The yeast network is more similar to a scale-free network than a random network in the above dynamical properties.

  19. Amino Acid Catabolism in Plants.

    Science.gov (United States)

    Hildebrandt, Tatjana M; Nunes Nesi, Adriano; Araújo, Wagner L; Braun, Hans-Peter

    2015-11-02

    Amino acids have various prominent functions in plants. Besides their usage during protein biosynthesis, they also represent building blocks for several other biosynthesis pathways and play pivotal roles during signaling processes as well as in plant stress response. In general, pool sizes of the 20 amino acids differ strongly and change dynamically depending on the developmental and physiological state of the plant cell. Besides amino acid biosynthesis, which has already been investigated in great detail, the catabolism of amino acids is of central importance for adjusting their pool sizes but so far has drawn much less attention. The degradation of amino acids can also contribute substantially to the energy state of plant cells under certain physiological conditions, e.g. carbon starvation. In this review, we discuss the biological role of amino acid catabolism and summarize current knowledge on amino acid degradation pathways and their regulation in the context of plant cell physiology.

  20. Promoters, Transcripts, and Regulatory Proteins of Mungbean Yellow Mosaic Geminivirus†

    OpenAIRE

    Shivaprasad, P. V.; Akbergenov, Rashid; Trinks, Daniela; R Rajeswaran; Veluthambi, K; Hohn, Thomas; Pooggin, Mikhail M.

    2005-01-01

    Geminiviruses package circular single-stranded DNA and replicate in the nucleus via a double-stranded intermediate. This intermediate also serves as a template for bidirectional transcription by polymerase II. Here, we map promoters and transcripts and characterize regulatory proteins of Mungbean yellow mosaic virus-Vigna (MYMV), a bipartite geminivirus in the genus Begomovirus. The following new features, which might also apply to other begomoviruses, were revealed in MYMV. The leftward and ...

  1. Crystal structure of nitrogen regulatory protein IIANtr from Neisseria meningitidis

    Directory of Open Access Journals (Sweden)

    Stammers David K

    2005-08-01

    Full Text Available Abstract Background The NMB0736 gene of Neisseria meningitidis serogroup B strain MC58 encodes the putative nitrogen regulatory protein, IIANtr (abbreviated to NM-IIANtr. The homologous protein present in Escherichia coli is implicated in the control of nitrogen assimilation. As part of a structural proteomics approach to the study of pathogenic Neisseria spp., we have selected this protein for structure determination by X-ray crystallography. Results The NM-IIANtr was over-expressed in E. coli and was shown to be partially mono-phosphorylated, as assessed by mass spectrometry of the purified protein. Crystals of un-phosphorylated protein were obtained and diffraction data collected to 2.5 Å resolution. The structure of NM-IIANtr was solved by molecular replacement using the coordinates of the E. coli nitrogen regulatory protein IIAntr [PDB: 1A6J] as the starting model. The overall fold of the Neisseria enzyme shows a high degree of similarity to the IIANtr from E. coli, and the position of the phosphoryl acceptor histidine residue (H67 is conserved. The orientation of an adjacent arginine residue (R69 suggests that it may also be involved in coordinating the phosphate group. Comparison of the structure with that of E. coli IIAmtl complexed with HPr [PDB: 1J6T] indicates that NM-IIANtr binds in a similar way to the HPr-like enzyme in Neisseria. Conclusion The structure of NM-IIANtr confirms its assignment as a homologue of the IIANtr proteins found in a range of other Gram-negative bacteria. We conclude that the NM- IIANtr protein functions as part of a phosphorylation cascade which, in contrast to E. coli, shares the upstream phosphotransfer protein with the sugar uptake phosphoenolpyruvate:sugar phosphotransferase system (PTS, but in common with E. coli has a distinct downstream effector mechanism.

  2. Krill protein hydrolysate reduces plasma triacylglycerol level with concurrent increase in plasma bile acid level and hepatic fatty acid catabolism in high-fat fed mice

    Directory of Open Access Journals (Sweden)

    Marie S. Ramsvik

    2013-11-01

    Full Text Available Background: Krill powder, consisting of both lipids and proteins, has been reported to modulate hepatic lipid catabolism in animals. Fish protein hydrolysate diets have also been reported to affect lipid metabolism and to elevate bile acid (BA level in plasma. BA interacts with a number of nuclear receptors and thus affects a variety of signaling pathways, including very low density lipoprotein (VLDL secretion. The aim of the present study was to investigate whether a krill protein hydrolysate (KPH could affect lipid and BA metabolism in mice. Method: C57BL/6 mice were fed a high-fat (21%, w/w diet containing 20% crude protein (w/w as casein (control group or KPH for 6 weeks. Lipids and fatty acid composition were measured from plasma, enzyme activity and gene expression were analyzed from liver samples, and BA was measured from plasma. Results: The effect of dietary treatment with KPH resulted in reduced levels of plasma triacylglycerols (TAG and non-esterified fatty acids (NEFAs. The KPH treated mice had also a marked increased plasma BA concentration. The increased plasma BA level was associated with induction of genes related to membrane canalicular exporter proteins (Abcc2, Abcb4 and to BA exporters to blood (Abcc3 and Abcc4. Of note, we observed a 2-fold increased nuclear farnesoid X receptor (Fxr mRNA levels in the liver of mice fed KPH. We also observed increased activity of the nuclear peroxiosme proliferator-activated receptor alpha (PPARα target gene carnitine plamitoyltransferase 2 (CPT-2. Conclusion: The KPH diet showed to influence lipid and BA metabolism in high-fat fed mice. Moreover, increased mitochondrial fatty acid oxidation and elevation of BA concentration may regulate the plasma level of TAGs and NEFAs.

  3. Ectoine-Induced Proteins in Sinorhizobium meliloti Include an Ectoine ABC-Type Transporter Involved in Osmoprotection and Ectoine Catabolism

    OpenAIRE

    Jebbar, Mohamed; Sohn-Bösser, Linda; Bremer, Erhard; Bernard, Théophile; Blanco, Carlos

    2005-01-01

    To understand the mechanisms of ectoine-induced osmoprotection in Sinorhizobium meliloti, a proteomic examination of S. meliloti cells grown in minimal medium supplemented with ectoine was undertaken. This revealed the induction of 10 proteins. The protein products of eight genes were identified by using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry. Five of these genes, with four other genes whose products were not detected on two-dimensional gels, belong to th...

  4. QM/MM investigation of the reaction rates of substrates of 2,3-dimethylmalate lyase: A catabolic protein isolated from Aspergillus niger.

    Science.gov (United States)

    Chotpatiwetchkul, Warot; Jongkon, Nathjanan; Hannongbua, Supa; Gleeson, M Paul

    2016-07-01

    Aspergillus niger is an industrially important microorganism used in the production of citric acid. It is a common cause of food spoilage and represents a health issue for patients with compromised immune systems. Recent studies on Aspergillus niger have revealed details on the isocitrate lyase (ICL) superfamily and its role in catabolism, including (2R, 3S)-dimethylmalate lyase (DMML). Members of this and related lyase super families are of considerable interest as potential treatments for bacterial and fungal infections, including Tuberculosis. In our efforts to better understand this class of protein, we investigate the catalytic mechanism of DMML, studying five different substrates and two different active site metals configurations using molecular dynamics (MD) and hybrid quantum mechanics/molecular mechanics (QM/MM) calculations. We show that the predicted barriers to reaction for the substrates show good agreement with the experimental kcat values. This results help to confirm the validity of the proposed mechanism and open up the possibility of developing novel mechanism based inhibitors specifically for this target.

  5. Laboratory tests for disorders of complement and complement regulatory proteins.

    Science.gov (United States)

    Shih, Angela R; Murali, Mandakolathur R

    2015-12-01

    The complement pathway is a cascade of proteases that is involved in immune surveillance and innate immunity, as well as adaptive immunity. Dysfunction of the complement cascade may be mediated by aberrations in the pathways of activation, complement regulatory proteins, or complement deficiencies, and has been linked to a number of hematologic disorders, including paroxysmal noctural hemoglobinuria (PNH), hereditary angioedema (HAE), and atypical hemolytic-uremic syndrome (aHUS). Here, current laboratory tests for disorders of the complement pathway are reviewed, and their utility and limitations in hematologic disorders and systemic diseases are discussed. Current therapeutic advances targeting the complement pathway in treatment of complement-mediated hematologic disorders are also reviewed.

  6. A whole-grain-rich diet reduces urinary excretion of markers of protein catabolism and gut microbiota metabolism in healthy men after one week.

    Science.gov (United States)

    Ross, Alastair B; Pere-Trépat, Emma; Montoliu, Ivan; Martin, Francois-Pierre J; Collino, Sebastiano; Moco, Sofia; Godin, Jean-Philippe; Cléroux, Marilyn; Guy, Philippe A; Breton, Isabelle; Bibiloni, Rodrigo; Thorimbert, Anita; Tavazzi, Isabelle; Tornier, Lionel; Bebuis, Aude; Bruce, Stephen J; Beaumont, Maurice; Fay, Laurent-Bernard; Kochhar, Sunil

    2013-06-01

    Epidemiological studies consistently find that diets rich in whole-grain (WG) cereals lead to decreased risk of disease compared with refined grain (RG)-based diets. Aside from a greater amount of fiber and micronutrients, possible mechanisms for why WGs may be beneficial for health remain speculative. In an exploratory, randomized, researcher-blinded, crossover trial, we measured metabolic profile differences between healthy participants eating a diet based on WGs compared with a diet based on RGs. Seventeen healthy adult participants (11 female, 6 male) consumed a controlled diet based on either WG-rich or RG-rich foods for 2 wk, followed by the other diet after a 5-wk washout period. Both diets were the same except for the use of WG (150 g/d) or RG foods. The metabolic profiles of plasma, urine, and fecal water were measured using (1)H-nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry (plasma only). After 1 wk of intervention, the WG diet led to decreases in urinary excretion of metabolites related to protein catabolism (urea, methylguanadine), lipid (carnitine and acylcarnitines) and gut microbial (4-hydroxyphenylacetate, trimethylacetate, dimethylacetate) metabolism in men compared with the same time point during the RG intervention. There were no differences between the interventions after 2 wk. Urinary urea, carnitine, and acylcarnitine were lower at wk 1 of the WG intervention relative to the RG intervention in all participants. Fecal water short-chain fatty acids acetate and butyrate were relatively greater after the WG diet compared to the RG diet. Although based on a small population and for a short time period, these observations suggest that a WG diet may affect protein metabolism.

  7. Exploitation of complement regulatory proteins by Borrelia and Francisella.

    Science.gov (United States)

    Madar, Marian; Bencurova, Elena; Mlynarcik, Patrik; Almeida, André M; Soares, Renata; Bhide, Katarina; Pulzova, Lucia; Kovac, Andrej; Coelho, Ana V; Bhide, Mangesh

    2015-06-01

    Pathogens have developed sophisticated mechanisms of complement evasion such as binding to the host complement regulatory proteins (CRPs) on their surface or expression of CRP mimicking molecules. The ability of pathogens to evade the complement system has been correlated with pathogenesis and host selectivity. Hitherto, little work has been undertaken to determine whether Borrelia and Francisella exploit various CRPs to block complement attack. Seventeen Borrelia (twelve species) and six Francisella (three subspecies) strains were used to assess their ability to bind human, sheep and cattle CRPs or mimic membrane associated complement regulators. A series of experiments including affinity ligand binding experiments, pull-down assays and mass spectrometry based protein identification, revealed an array of CRP binding proteins of Borrelia and Francisella. Unlike Francisella, Borrelia strains were able to bind multiple human CRPs. Three strains of Borrelia (SKT-4, SKT-2 and HO14) showed the presence of a human CD46-homologous motif, indicating their ability to possess putative human CD46 mimicking molecules. Similarly, five strains of Borrelia and two strains of Francisella may have surface proteins with human CD59-homologous motifs. Among ovine and bovine CRPs, the only CRP bound by Francisella (LVS, Tul4 strain) was vitronectin, while ovine C4BP, ovine factor H and bovine factor H were bound to Borrelia strains SKT-2, DN127 and Co53. This study presents an array of proteins of Borrelia and Francisella that bind CRPs or may mimic membrane-CRPs, thus enabling multiphasic complement evasion strategies of these pathogens.

  8. Promoters, Transcripts, and Regulatory Proteins of Mungbean Yellow Mosaic Geminivirus†

    Science.gov (United States)

    Shivaprasad, P. V.; Akbergenov, Rashid; Trinks, Daniela; Rajeswaran, R.; Veluthambi, K.; Hohn, Thomas; Pooggin, Mikhail M.

    2005-01-01

    Geminiviruses package circular single-stranded DNA and replicate in the nucleus via a double-stranded intermediate. This intermediate also serves as a template for bidirectional transcription by polymerase II. Here, we map promoters and transcripts and characterize regulatory proteins of Mungbean yellow mosaic virus-Vigna (MYMV), a bipartite geminivirus in the genus Begomovirus. The following new features, which might also apply to other begomoviruses, were revealed in MYMV. The leftward and rightward promoters on DNA-B share the transcription activator AC2-responsive region, which does not overlap the common region that is nearly identical in the two DNA components. The transcription unit for BC1 (movement protein) includes a conserved, leader-based intron. Besides negative-feedback regulation of its own leftward promoter on DNA-A, the replication protein AC1, in cooperation with AC2, synergistically transactivates the rightward promoter, which drives a dicistronic transcription unit for the coat protein AV1. AC2 and the replication enhancer AC3 are expressed from one dicistronic transcript driven by a strong promoter mapped within the upstream AC1 gene. Early and constitutive expression of AC2 is consistent with its essential dual function as an activator of viral transcription and a suppressor of silencing. PMID:15956560

  9. Promoters, transcripts, and regulatory proteins of Mungbean yellow mosaic geminivirus.

    Science.gov (United States)

    Shivaprasad, P V; Akbergenov, Rashid; Trinks, Daniela; Rajeswaran, R; Veluthambi, K; Hohn, Thomas; Pooggin, Mikhail M

    2005-07-01

    Geminiviruses package circular single-stranded DNA and replicate in the nucleus via a double-stranded intermediate. This intermediate also serves as a template for bidirectional transcription by polymerase II. Here, we map promoters and transcripts and characterize regulatory proteins of Mungbean yellow mosaic virus-Vigna (MYMV), a bipartite geminivirus in the genus Begomovirus. The following new features, which might also apply to other begomoviruses, were revealed in MYMV. The leftward and rightward promoters on DNA-B share the transcription activator AC2-responsive region, which does not overlap the common region that is nearly identical in the two DNA components. The transcription unit for BC1 (movement protein) includes a conserved, leader-based intron. Besides negative-feedback regulation of its own leftward promoter on DNA-A, the replication protein AC1, in cooperation with AC2, synergistically transactivates the rightward promoter, which drives a dicistronic transcription unit for the coat protein AV1. AC2 and the replication enhancer AC3 are expressed from one dicistronic transcript driven by a strong promoter mapped within the upstream AC1 gene. Early and constitutive expression of AC2 is consistent with its essential dual function as an activator of viral transcription and a suppressor of silencing.

  10. Iron Regulatory Proteins Mediate Host Resistance to Salmonella Infection.

    Science.gov (United States)

    Nairz, Manfred; Ferring-Appel, Dunja; Casarrubea, Daniela; Sonnweber, Thomas; Viatte, Lydie; Schroll, Andrea; Haschka, David; Fang, Ferric C; Hentze, Matthias W; Weiss, Guenter; Galy, Bruno

    2015-08-12

    Macrophages are essential for systemic iron recycling, and also control iron availability to pathogens. Iron metabolism in mammalian cells is orchestrated posttranscriptionally by iron-regulatory proteins (IRP)-1 and -2. Here, we generated mice with selective and combined ablation of both IRPs in macrophages to investigate the role of IRPs in controlling iron availability. These animals are hyperferritinemic but otherwise display normal clinical iron parameters. However, mutant mice rapidly succumb to systemic infection with Salmonella Typhimurium, a pathogenic bacterium that multiplies within macrophages, with increased bacterial burdens in liver and spleen. Ex vivo infection experiments indicate that IRP function restricts bacterial access to iron via the EntC and Feo bacterial iron-acquisition systems. Further, IRPs contain Salmonella by promoting the induction of lipocalin 2, a host antimicrobial factor that inhibits bacterial uptake of iron-laden siderophores, and by suppressing the ferritin iron pool. This work reveals the importance of the IRPs in innate immunity.

  11. Enzymatic Mercury Detoxification: The Regulatory Protein MerR

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    Ctortecka, B; Walsh, C T; Comess, K M

    2002-01-01

    Mercury ions and organomercurial reagents are extremely toxic due to their affinity for thiol groups. Many bacteria contain an elaborate detoxification system for a metabolic conversion of toxic Hg$^{2+}$ or organomercurials to less toxic elemental Hg$^0$. The main components of the enzymatic mercury detoxification (see Fig. 1) are the regulatory protein MerR (mercury responsive genetic switch), the organomercurial lyase MerB (cleavage of carbon mercury bonds), and the mercuric ion reductase MerA (reduction of mercuric ions). In these proteins Hg$^{2+}$ is usually coordinated by the thiol groups of cysteines. We utilize the nuclear quadrupole interaction (NQI) of ${\\rm^{199m}}$Hg detected by time differential perturbed angular correlation (TDPAC) to identify the Hg metal site geometries in these proteins in order to elucidate the molecular origin of the ultrasensitivity, selectivity and reaction mechanism of this detoxification system. The short lived TDPAC probe ${\\rm^{199m}}$Hg ($\\tau_{1/2} =$ 43 min) is su...

  12. Maintaining cholesterol homeostasis:Sterol regulatory element-binding proteins

    Institute of Scientific and Technical Information of China (English)

    Lutz W. Weber; Meinrad Boll; Andreas Stampfl

    2004-01-01

    The molecular mechanism of how hepatocytes maintain cholesterol homeostasis has become much more transparent with the discovery of sterol regulatory element binding proteins (SREBPs) in recent years. These membrane proteins are members of the basic helix-loop-helix-leucine zipper (bHLHZip) family of transcription factors. They activate the expression of at least 30 genes involved in the synthesis of cholesterol and lipids. SREBPs are synthesized as precursor proteins in the endoplasmic reticulum (ER), where they form a complex with another protein, SREBP cleavage activating protein (SCAP).The SCAP molecule contains a sterol sensory domain. In the presence of high cellular sterol concentrations SCAP confines SREBP to the ER. With low cellular concentrations, SCAP escorts SREBP to activation in the Golgi. There, SREBP undergoes two proteolytic cleavage steps to release the mature, biologically active transcription factor, nuclear SREBP (nSREBP). nSREBP translocates to the nucleus and binds to sterol response elements (SRE) in the promoter/enhancer regions of target genes. Additional transcription factors are required to activate transcription of these genes. Three different SREBPs are known, SREBPs-1a, -1c and -2. SREBP-1a and -1c are isoforms produced from a single gene by alternate splicing. SREBP-2is encoded by a different gene and does not display any isoforms. It appears that SREBPs alone, in the sequence described above, can exert complete control over cholesterol synthesis, whereas many additional factors (hormones,cytokines, etc.) are required for complete control of lipid metabolism. Medicinal manipulation of the SREBP/SCAP system is expected to prove highly beneficial in the management of cholesterol-related disease.

  13. Pleiotropy constrains the evolution of protein but not regulatory sequences in a transcription regulatory network influencing complex social behaviours

    Directory of Open Access Journals (Sweden)

    Daria eMolodtsova

    2014-12-01

    Full Text Available It is increasingly apparent that genes and networks that influence complex behaviour are evolutionary conserved, which is paradoxical considering that behaviour is labile over evolutionary timescales. How does adaptive change in behaviour arise if behaviour is controlled by conserved, pleiotropic, and likely evolutionary constrained genes? Pleiotropy and connectedness are known to constrain the general rate of protein evolution, prompting some to suggest that the evolution of complex traits, including behaviour, is fuelled by regulatory sequence evolution. However, we seldom have data on the strength of selection on mutations in coding and regulatory sequences, and this hinders our ability to study how pleiotropy influences coding and regulatory sequence evolution. Here we use population genomics to estimate the strength of selection on coding and regulatory mutations for a transcriptional regulatory network that influences complex behaviour of honey bees. We found that replacement mutations in highly connected transcription factors and target genes experience significantly stronger negative selection relative to weakly connected transcription factors and targets. Adaptively evolving proteins were significantly more likely to reside at the periphery of the regulatory network, while proteins with signs of negative selection were near the core of the network. Interestingly, connectedness and network structure had minimal influence on the strength of selection on putative regulatory sequences for both transcription factors and their targets. Our study indicates that adaptive evolution of complex behaviour can arise because of positive selection on protein-coding mutations in peripheral genes, and on regulatory sequence mutations in both transcription factors and their targets throughout the network.

  14. Influence of anesthesia and surgery on the expression of transport receptors and catabolic enzymes of amyloid β-protein in aged rats

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    Yong-zhe LIU

    2014-10-01

    Full Text Available Objective To investigate the expression changes in transport receptor and catabolic enzymes of amyloid β-protein (Aβ in the brain of aged rats after surgery. Methods One hundred healthy SD rats were randomly divided into 4 groups according to their ages: aged control group (n=10, aged surgery group (n=40, young control group (n=10, and young surgery group (n=40. Rats in surgery group underwent hepatic lobectomy under anesthesia with 2% sevoflurane, followed by a 2-hour continuous anesthesia after the surgery, and then sacrificed on the 1st, 3rd, 7th and 15th day after surgery to obtain specimens. The expression of low-density lipoprotein receptor-related protein 1 (LRP-1 and receptor for advanced glycation end products (RAGE in the hippocampus, and the expression of insulin-degrading enzyme (IDE and neprilysin (NEP in the cerebral cortex were determined by immunohistochemistry. The mRNA expression of IDE and NEP in the hippocampus was determined with RT-PCR. Results Compared with aged control group, the expression of LRP-1, NEP and NEP mRNA decreased and the expression of RAGE increased at each time point, the expression of IDE decreased at 1st and 15th day after surgery, and the expression of IDE mRNA decreased at 3rd and 7th day and increased at 15th day after surgery in aged surgery group (P<0.05, P<0.01. Compared with young control group, the expression of IDE mRNA decreased and expressions of RAGE and NEP mRNA increased at each time point, the expression of LRP-1 decreased at 3rd, 7th and 15th day, the expression of IDE decreased at 1st, 3rd day and increased at 15th day, and the expression of NEP increased at 1st day and decreased at 3rd, 7th and 15th day after surgery in young surgery group (P<0.05, P<0.01. Conclusion The procedure of anesthesia and surgery could significantly inhibit the outward transport and enzymatic degradation of Aβ in the brain of aged rats, and this effect is less evident in young rats. DOI: 10.11855/j

  15. Protein modularity, cooperative binding, and hybrid regulatory states underlie transcriptional network diversification.

    Science.gov (United States)

    Baker, Christopher R; Booth, Lauren N; Sorrells, Trevor R; Johnson, Alexander D

    2012-09-28

    We examine how different transcriptional network structures can evolve from an ancestral network. By characterizing how the ancestral mode of gene regulation for genes specific to a-type cells in yeast species evolved from an activating paradigm to a repressing one, we show that regulatory protein modularity, conversion of one cis-regulatory sequence to another, distribution of binding energy among protein-protein and protein-DNA interactions, and exploitation of ancestral network features all contribute to the evolution of a novel regulatory mode. The formation of this derived mode of regulation did not disrupt the ancestral mode and thereby created a hybrid regulatory state where both means of transcription regulation (ancestral and derived) contribute to the conserved expression pattern of the network. Finally, we show how this hybrid regulatory state has resolved in different ways in different lineages to generate the diversity of regulatory network structures observed in modern species.

  16. Effects of ingesting protein with various forms of carbohydrate following resistance-exercise on substrate availability and markers of anabolism, catabolism, and immunity

    Directory of Open Access Journals (Sweden)

    Greenwood Michael

    2007-11-01

    Full Text Available Abstract Background Ingestion of carbohydrate (CHO and protein (PRO following intense exercise has been reported to increase insulin levels, optimize glycogen resynthesis, enhance PRO synthesis, and lessen the immuno-suppressive effects of intense exercise. Since different forms of CHO have varying glycemic effects, the purpose of this study was to determine whether the type of CHO ingested with PRO following resistance-exercise affects blood glucose availability and insulin levels, markers of anabolism and catabolism, and/or general immune markers. Methods 40 resistance-trained subjects performed a standardized resistance training workout and then ingested in a double blind and randomized manner 40 g of whey PRO with 120 g of sucrose (S, honey powder (H, or maltodextrin (M. A non-supplemented control group (C was also evaluated. Blood samples were collected prior to and following exercise as well as 30, 60, 90, and 120 min after ingestion of the supplements. Data were analyzed by repeated measures ANOVA or ANCOVA using baseline values as a covariate if necessary. Results Glucose concentration 30 min following ingestion showed the H group (7.12 ± 0.2 mmol/L to be greater than S (5.53 ± 0.6 mmol/L; p uIU/mL, H (150.1 ± 25.39 uIU/mL, and M (154.8 ± 18.9 uIU/mL were greater than C (8.7 ± 2.9 uIU/mL as was AUC with no significant differences observed among types of CHO. No significant group × time effects were observed among groups in testosterone, cortisol, the ratio of testosterone to cortisol, muscle and liver enzymes, or general markers of immunity. Conclusion CHO and PRO ingestion following exercise significantly influences glucose and insulin concentrations. Although some trends were observed suggesting that H maintained blood glucose levels to a better degree, no significant differences were observed among types of CHO ingested on insulin levels. These findings suggest that each of these forms of CHO can serve as effective sources of

  17. The Evolution of the Secreted Regulatory Protein Progranulin.

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    Roger G E Palfree

    Full Text Available Progranulin is a secreted growth factor that is active in tumorigenesis, wound repair, and inflammation. Haploinsufficiency of the human progranulin gene, GRN, causes frontotemporal dementia. Progranulins are composed of chains of cysteine-rich granulin modules. Modules may be released from progranulin by proteolysis as 6kDa granulin polypeptides. Both intact progranulin and some of the granulin polypeptides are biologically active. The granulin module occurs in certain plant proteases and progranulins are present in early diverging metazoan clades such as the sponges, indicating their ancient evolutionary origin. There is only one Grn gene in mammalian genomes. More gene-rich Grn families occur in teleost fish with between 3 and 6 members per species including short-form Grns that have no tetrapod counterparts. Our goals are to elucidate progranulin and granulin module evolution by investigating (i: the origins of metazoan progranulins (ii: the evolutionary relationships between the single Grn of tetrapods and the multiple Grn genes of fish (iii: the evolution of granulin module architectures of vertebrate progranulins (iv: the conservation of mammalian granulin polypeptide sequences and how the conserved granulin amino acid sequences map to the known three dimensional structures of granulin modules. We report that progranulin-like proteins are present in unicellular eukaryotes that are closely related to metazoa suggesting that progranulin is among the earliest extracellular regulatory proteins still employed by multicellular animals. From the genomes of the elephant shark and coelacanth we identified contemporary representatives of a precursor for short-from Grn genes of ray-finned fish that is lost in tetrapods. In vertebrate Grns pathways of exon duplication resulted in a conserved module architecture at the amino-terminus that is frequently accompanied by an unusual pattern of tandem nearly identical module repeats near the carboxyl

  18. Regulation of myo-inositol catabolism by a GntR-type repressor SCO6974 in Streptomyces coelicolor.

    Science.gov (United States)

    Yu, Lingjun; Li, Shuxian; Gao, Wenyan; Pan, Yuanyuan; Tan, Huarong; Liu, Gang

    2015-04-01

    Myo-inositol is important for Streptomyces growth and morphological differentiation. Genomic sequence analysis revealed a myo-inositol catabolic gene cluster in Streptomyces coelicolor. Disruption of the corresponding genes in this cluster abolished the bacterial growth on myo-inositol as a single carbon source. The transcriptions of these genes were remarkably enhanced by addition of myo-inositol in minimal medium. A putative regulatory gene SCO6974, encoding a GntR family protein, is situated in the cluster. Disruption of SCO6974 significantly enhanced the transcription of myo-inositol catabolic genes. SCO6974 was shown to interact with the promoter regions of myo-inositol catabolic genes using electrophoretic mobility shift assays. DNase I footprinting assays demonstrated that SCO6974 recognized a conserved palindromic sequence (A/T)TGT(A/C)N(G/T)(G/T)ACA(A/T). Base substitution of the conserved sequence completely abolished the binding of SCO6974 to the targets demonstrating that SCO6974 directly represses the transcriptions of myo-inositol catabolic genes. Furthermore, the disruption of SCO6974 was correlated with a reduced sporulation of S. coelicolor in mannitol soya flour medium and with the overproduction of actinorhodin and calcium-dependent antibiotic. The addition of myo-inositol suppressed the sporulation deficiency of the mutant, indicating that the effect could be related to a shortage in myo-inositol due to its enhanced catabolism in this strain. This enhanced myo-inositol catabolism likely yields dihydroxyacetone phosphate and acetyl-CoA that are indirect or direct precursors of the overproduced antibiotics.

  19. Body weight independently affects articular cartilage catabolism.

    Science.gov (United States)

    Denning, W Matt; Winward, Jason G; Pardo, Michael Becker; Hopkins, J Ty; Seeley, Matthew K

    2015-06-01

    Although obesity is associated with osteoarthritis, it is unclear whether body weight (BW) independently affects articular cartilage catabolism (i.e., independent from physiological factors that also accompany obesity). The primary purpose of this study was to evaluate the independent effect of BW on articular cartilage catabolism associated with walking. A secondary purpose was to determine how decreased BW influenced cardiovascular response due to walking. Twelve able-bodied subjects walked for 30 minutes on a lower-body positive pressure treadmill during three sessions: control (unadjusted BW), +40%BW, and -40%BW. Serum cartilage oligomeric matrix protein (COMP) was measured immediately before (baseline) and after, and 15 and 30 minutes after the walk. Heart rate (HR) and rate of perceived exertion (RPE) were measured every three minutes during the walk. Relative to baseline, average serum COMP concentration was 13% and 5% greater immediately after and 15 minutes after the walk. Immediately after the walk, serum COMP concentration was 14% greater for the +40%BW session than for the -40%BW session. HR and RPE were greater for the +40%BW session than for the other two sessions, but did not differ between the control and -40%BW sessions. BW independently influences acute articular cartilage catabolism and cardiovascular response due to walking: as BW increases, so does acute articular cartilage catabolism and cardiovascular response. These results indicate that lower-body positive pressure walking may benefit certain individuals by reducing acute articular cartilage catabolism, due to walking, while maintaining cardiovascular response. Key pointsWalking for 30 minutes with adjustments in body weight (normal body weight, +40% and -40% body weight) significantly influences articular cartilage catabolism, measured via serum COMP concentration.Compared to baseline levels, walking with +40% body weight and normal body weight both elicited significant increases in

  20. Antidiabetic effects of glucokinase regulatory protein small-molecule disruptors

    Science.gov (United States)

    Lloyd, David J.; St Jean, David J.; Kurzeja, Robert J. M.; Wahl, Robert C.; Michelsen, Klaus; Cupples, Rod; Chen, Michelle; Wu, John; Sivits, Glenn; Helmering, Joan; Komorowski, Renée; Ashton, Kate S.; Pennington, Lewis D.; Fotsch, Christopher; Vazir, Mukta; Chen, Kui; Chmait, Samer; Zhang, Jiandong; Liu, Longbin; Norman, Mark H.; Andrews, Kristin L.; Bartberger, Michael D.; van, Gwyneth; Galbreath, Elizabeth J.; Vonderfecht, Steven L.; Wang, Minghan; Jordan, Steven R.; Véniant, Murielle M.; Hale, Clarence

    2013-12-01

    Glucose homeostasis is a vital and complex process, and its disruption can cause hyperglycaemia and type II diabetes mellitus. Glucokinase (GK), a key enzyme that regulates glucose homeostasis, converts glucose to glucose-6-phosphate in pancreatic β-cells, liver hepatocytes, specific hypothalamic neurons, and gut enterocytes. In hepatocytes, GK regulates glucose uptake and glycogen synthesis, suppresses glucose production, and is subject to the endogenous inhibitor GK regulatory protein (GKRP). During fasting, GKRP binds, inactivates and sequesters GK in the nucleus, which removes GK from the gluconeogenic process and prevents a futile cycle of glucose phosphorylation. Compounds that directly hyperactivate GK (GK activators) lower blood glucose levels and are being evaluated clinically as potential therapeutics for the treatment of type II diabetes mellitus. However, initial reports indicate that an increased risk of hypoglycaemia is associated with some GK activators. To mitigate the risk of hypoglycaemia, we sought to increase GK activity by blocking GKRP. Here we describe the identification of two potent small-molecule GK-GKRP disruptors (AMG-1694 and AMG-3969) that normalized blood glucose levels in several rodent models of diabetes. These compounds potently reversed the inhibitory effect of GKRP on GK activity and promoted GK translocation both in vitro (isolated hepatocytes) and in vivo (liver). A co-crystal structure of full-length human GKRP in complex with AMG-1694 revealed a previously unknown binding pocket in GKRP distinct from that of the phosphofructose-binding site. Furthermore, with AMG-1694 and AMG-3969 (but not GK activators), blood glucose lowering was restricted to diabetic and not normoglycaemic animals. These findings exploit a new cellular mechanism for lowering blood glucose levels with reduced potential for hypoglycaemic risk in patients with type II diabetes mellitus.

  1. Basal autophagy is required for the efficient catabolism of sialyloligosaccharides.

    Science.gov (United States)

    Seino, Junichi; Wang, Li; Harada, Yoichiro; Huang, Chengcheng; Ishii, Kumiko; Mizushima, Noboru; Suzuki, Tadashi

    2013-09-13

    Macroautophagy is an essential, homeostatic process involving degradation of a cell's own components; it plays a role in catabolizing cellular components, such as protein or lipids, and damaged or excess organelles. Here, we show that in Atg5(-/-) cells, sialyloligosaccharides specifically accumulated in the cytosol. Accumulation of these glycans was observed under non-starved conditions, suggesting that non-induced, basal autophagy is essential for their catabolism. Interestingly, once accumulated in the cytosol, sialylglycans cannot be efficiently catabolized by resumption of the autophagic process, suggesting that functional autophagy is important for preventing sialyloligosaccharides from accumulating in the cytosol. Moreover, knockdown of sialin, a lysosomal transporter of sialic acids, resulted in a significant reduction of sialyloligosaccharides, implying that autophagy affects the substrate specificity of this transporter. This study thus provides a surprising link between basal autophagy and catabolism of N-linked glycans.

  2. Type One Protein Phosphatase 1 and Its Regulatory Protein Inhibitor 2 Negatively Regulate ABA Signaling

    Science.gov (United States)

    Zhao, Yang; Xie, Shaojun; Batelli, Giorgia; Wang, Bangshing; Duan, Cheng-Guo; Wang, Xingang; Xing, Lu; Lei, Mingguang; Yan, Jun; Zhu, Xiaohong; Zhu, Jian-Kang

    2016-01-01

    The phytohormone abscisic acid (ABA) regulates plant growth, development and responses to biotic and abiotic stresses. The core ABA signaling pathway consists of three major components: ABA receptor (PYR1/PYLs), type 2C Protein Phosphatase (PP2C) and SNF1-related protein kinase 2 (SnRK2). Nevertheless, the complexity of ABA signaling remains to be explored. To uncover new components of ABA signal transduction pathways, we performed a yeast two-hybrid screen for SnRK2-interacting proteins. We found that Type One Protein Phosphatase 1 (TOPP1) and its regulatory protein, At Inhibitor-2 (AtI-2), physically interact with SnRK2s and also with PYLs. TOPP1 inhibited the kinase activity of SnRK2.6, and this inhibition could be enhanced by AtI-2. Transactivation assays showed that TOPP1 and AtI-2 negatively regulated the SnRK2.2/3/6-mediated activation of the ABA responsive reporter gene RD29B, supporting a negative role of TOPP1 and AtI-2 in ABA signaling. Consistent with these findings, topp1 and ati-2 mutant plants displayed hypersensitivities to ABA and salt treatments, and transcriptome analysis of TOPP1 and AtI-2 knockout plants revealed an increased expression of multiple ABA-responsive genes in the mutants. Taken together, our results uncover TOPP1 and AtI-2 as negative regulators of ABA signaling. PMID:26943172

  3. Novel inositol catabolic pathway in Thermotoga maritima.

    Science.gov (United States)

    Rodionova, Irina A; Leyn, Semen A; Burkart, Michael D; Boucher, Nathalie; Noll, Kenneth M; Osterman, Andrei L; Rodionov, Dmitry A

    2013-08-01

    myo-inositol (MI) is a key sugar alcohol component of various metabolites, e.g. phosphatidylinositol-based phospholipids that are abundant in animal and plant cells. The seven-step pathway of MI degradation was previously characterized in various soil bacteria including Bacillus subtilis. Through a combination of bioinformatics and experimental techniques we identified a novel variant of the MI catabolic pathway in the marine hyperthermophilic bacterium Thermotoga maritima. By using in vitro biochemical assays with purified recombinant proteins we characterized four inositol catabolic enzymes encoded in the TM0412-TM0416 chromosomal gene cluster. The novel catabolic pathway in T. maritima starts as the conventional route using the myo-inositol dehydrogenase IolG followed by three novel reactions. The first 2-keto-myo-inositol intermediate is oxidized by another, previously unknown NAD-dependent dehydrogenase TM0412 (named IolM), and a yet unidentified product of this reaction is further hydrolysed by TM0413 (IolN) to form 5-keto-l-gluconate. The fourth step involves epimerization of 5-keto-l-gluconate to d-tagaturonate by TM0416 (IolO). T. maritima is unable to grow on myo-inositol as a single carbon source. The determined in vitro specificity of the InoEFGK (TM0418-TM0421) transporter to myo-inositol-phosphate suggests that the novel pathway in Thermotoga utilizes a phosphorylated derivative of inositol.

  4. Development of coagulation regulatory proteins in the fetal and neonatal lamb.

    Science.gov (United States)

    Manco-Johnson, Marilyn J; Jacobson, Linda J; Hacker, Michele R; Townsend, Susan F; Murphy, James; Hay, William

    2002-10-01

    To investigate the development of coagulation regulatory proteins-protein C (PC), protein S (PS), and antithrombin (AT)-in relationship to the procoagulant protein factor X (FX), a chronically catheterized fetal ovine model was used. Infusion and sampling catheters were placed into pregnant ewes and their fetuses and maintained from mid-gestation. From a total of 110 fetuses, 17 lambs, and 63 ewes that were studied on one to 15 occasions, 212 fetal, 88 neonatal, and 157 maternal samples were obtained. Liver tissue was obtained from 31 fetuses and 15 ewes. Plasma levels of all proteins studied were higher in the ewe than in the fetus (p 0.05). This study suggests that fetal regulation of coagulation proteins follows characteristic patterns relative to the vitamin K dependence of the protein rather than its role as a procoagulant versus regulatory protein.

  5. Analysis of protein phosphatase-1 and aurora protein kinase suppressors reveals new aspects of regulatory protein function in Saccharomyces cerevisiae.

    Directory of Open Access Journals (Sweden)

    Anuprita Ghosh

    Full Text Available Protein phosphatase-1 (PP1 controls many processes in eukaryotic cells. Modulation of mitosis by reversing phosphorylation of proteins phosphorylated by aurora protein kinase is a critical function for PP1. Overexpression of the sole PP1, Glc7, in budding yeast, Saccharomyces cerevisiae, is lethal. This work shows that lethality requires the function of Glc7 regulatory proteins Sds22, Reg2, and phosphorylated Glc8. This finding shows that Glc7 overexpression induced cell death requires a specific subset of the many Glc7-interacting proteins and therefore is likely caused by promiscuous dephosphorylation of a variety of substrates. Additionally, suppression can occur by reducing Glc7 protein levels by high-copy Fpr3 without use of its proline isomerase domain. This divulges a novel function of Fpr3. Most suppressors of GLC7 overexpression also suppress aurora protein kinase, ipl1, temperature-sensitive mutations. However, high-copy mutant SDS22 genes show reciprocal suppression of GLC7 overexpression induced cell death or ipl1 temperature sensitivity. Sds22 binds to many proteins besides Glc7. The N-terminal 25 residues of Sds22 are sufficient to bind, directly or indirectly, to seven proteins studied here including the spindle assembly checkpoint protein, Bub3. These data demonstrate that Sds22 organizes several proteins in addition to Glc7 to perform functions that counteract Ipl1 activity or lead to hyper Glc7 induced cell death. These data also emphasize that Sds22 targets Glc7 to nuclear locations distinct from Ipl1 substrates.

  6. Renal catabolism of albumin – current views and controversies

    Directory of Open Access Journals (Sweden)

    Jakub Gburek

    2011-10-01

    Full Text Available Albumin is the main protein of blood plasma, lymph, cerebrospinal fluid and interstitial fluid. The protein assists in many important body functions, including maintenance of proper colloidal osmotic pressure, transport of important metabolites and antioxidant action. Synthesis of albumin takes place mainly in the liver, and its catabolism occurs mostly in vascular endothelium of muscle, skin and liver as well as in the kidney tubular epithelium. Renal catabolism of albumin consists of glomerular filtration and tubular reabsorption. The tubular processes include endocytosis via the multiligand scavenger receptor tandem megalin and cubilin-amnionless complex. Possible ways of further catabolism of this protein are lysosomal proteolysis to amino acids and short peptides, recycling of degradation products into the bloodstream and tubular lumen or transcytosis of whole molecules. The article discusses the molecular aspects of these processes and presents the controversies arising in the light of the last decade of research.

  7. Redox proteins of hydroxylating bacterial dioxygenases establish a regulatory cascade that prevents gratuitous induction of tetralin biodegradation genes

    Science.gov (United States)

    Ledesma-García, Laura; Sánchez-Azqueta, Ana; Medina, Milagros; Reyes-Ramírez, Francisca; Santero, Eduardo

    2016-01-01

    Bacterial dioxygenase systems are multicomponent enzymes that catalyze the initial degradation of many environmentally hazardous compounds. In Sphingopyxis granuli strain TFA tetralin dioxygenase hydroxylates tetralin, an organic contaminant. It consists of a ferredoxin reductase (ThnA4), a ferredoxin (ThnA3) and a oxygenase (ThnA1/ThnA2), forming a NAD(P)H–ThnA4–ThnA3–ThnA1/ThnA2 electron transport chain. ThnA3 has also a regulatory function since it prevents expression of tetralin degradation genes (thn) in the presence of non-metabolizable substrates of the catabolic pathway. This role is of physiological relevance since avoids gratuitous and wasteful production of catabolic enzymes. Our hypothesis for thn regulation implies that ThnA3 exerts its action by diverting electrons towards the regulator ThnY, an iron-sulfur flavoprotein that together with the transcriptional activator ThnR is necessary for thn gene expression. Here we analyze electron transfer among ThnA4, ThnA3 and ThnY by using stopped-flow spectrophotometry and determination of midpoint reduction potentials. Our results indicate that when accumulated in its reduced form ThnA3 is able to fully reduce ThnY. In addition, we have reproduced in vitro the regulatory circuit in the proposed physiological direction, NAD(P)H–ThnA4–ThnA3–ThnY. ThnA3 represents an unprecedented way of communication between a catabolic pathway and its regulatory system to prevent gratuitous induction. PMID:27030382

  8. Complement regulatory protein genes in channel catfish and their involvement in disease defense response.

    Science.gov (United States)

    Jiang, Chen; Zhang, Jiaren; Yao, Jun; Liu, Shikai; Li, Yun; Song, Lin; Li, Chao; Wang, Xiaozhu; Liu, Zhanjiang

    2015-11-01

    Complement system is one of the most important defense systems of innate immunity, which plays a crucial role in disease defense responses in channel catfish. However, inappropriate and excessive complement activation could lead to potential damage to the host cells. Therefore the complement system is controlled by a set of complement regulatory proteins to allow normal defensive functions, but prevent hazardous complement activation to host tissues. In this study, we identified nine complement regulatory protein genes from the channel catfish genome. Phylogenetic and syntenic analyses were conducted to determine their orthology relationships, supporting their correct annotation and potential functional inferences. The expression profiles of the complement regulatory protein genes were determined in channel catfish healthy tissues and after infection with the two main bacterial pathogens, Edwardsiella ictaluri and Flavobacterium columnare. The vast majority of complement regulatory protein genes were significantly regulated after bacterial infections, but interestingly were generally up-regulated after E. ictaluri infection while mostly down-regulated after F. columnare infection, suggesting a pathogen-specific pattern of regulation. Collectively, these findings suggested that complement regulatory protein genes may play complex roles in the host immune responses to bacterial pathogens in channel catfish.

  9. Dynamic SPR monitoring of yeast nuclear protein binding to a cis-regulatory element.

    Science.gov (United States)

    Mao, Grace; Brody, James P

    2007-11-09

    Gene expression is controlled by protein complexes binding to short specific sequences of DNA, called cis-regulatory elements. Expression of most eukaryotic genes is controlled by dozens of these elements. Comprehensive identification and monitoring of these elements is a major goal of genomics. In pursuit of this goal, we are developing a surface plasmon resonance (SPR) based assay to identify and monitor cis-regulatory elements. To test whether we could reliably monitor protein binding to a regulatory element, we immobilized a 16bp region of Saccharomyces cerevisiae chromosome 5 onto a gold surface. This 16bp region of DNA is known to bind several proteins and thought to control expression of the gene RNR1, which varies through the cell cycle. We synchronized yeast cell cultures, and then sampled these cultures at a regular interval. These samples were processed to purify nuclear lysate, which was then exposed to the sensor. We found that nuclear protein binds this particular element of DNA at a significantly higher rate (as compared to unsynchronized cells) during G1 phase. Other time points show levels of DNA-nuclear protein binding similar to the unsynchronized control. We also measured the apparent association complex of the binding to be 0.014s(-1). We conclude that (1) SPR-based assays can monitor DNA-nuclear protein binding and that (2) for this particular cis-regulatory element, maximum DNA-nuclear protein binding occurs during G1 phase.

  10. Bimolecular fluorescence complementation as a tool to study interactions of regulatory proteins in plant protoplasts.

    Science.gov (United States)

    Pattanaik, Sitakanta; Werkman, Joshua R; Yuan, Ling

    2011-01-01

    Protein-protein interactions are an important aspect of the gene regulation process. The expression of a gene in response to certain stimuli, within a specific cell type or at a particular developmental stage, involves a complex network of interactions between different regulatory proteins and the cis-regulatory elements present in the promoter of the gene. A number of methods have been developed to study protein-protein interactions in vitro and in vivo in plant cells, one of which is bimolecular fluorescence complementation (BiFC). BiFC is a relatively simple technique based upon the reconstitution of a fluorescent protein. The interacting protein complex can be visualized directly in a living plant cell when two non-fluorescent fragments, of an otherwise fluorescent protein, are fused to proteins found within that complex. Interaction of tagged proteins brings the two non-fluorescent fragments into close proximity and reconstitutes the fluorescent protein. In addition, the subcellular location of an interacting protein complex in the cell can be simultaneously determined. Using this approach, we have successfully demonstrated a protein-protein interaction between a R2R3 MYB and a basic helix-loop-helix MYC transcription factor related to flavonoid biosynthetic pathway in tobacco protoplasts.

  11. Physiological and regulatory effects of controlled overproduction of five cold shock proteins of Lactococcus lactis

    NARCIS (Netherlands)

    Wouters, J.A.; Mailhes, M.; Rombouts, F.M.; Vos, de W.M.; Kuipers, O.P.; Abee, T.

    2000-01-01

    The physiological and regulatory effects of overproduction of five cold shock proteins (CSPs) of Lactococcus lactis were studied. CspB, CspD, and CspE could be overproduced at high levels (up to 19␘f the total protein), whereas for CspA and CspC limited overproduction (0.3 to 0.5␘f the total protein

  12. Functional protein clusters and regulatory motifs in Hypsibius dujardini und Milnesium tardigradum

    OpenAIRE

    Förster, Frank; Liang, Chunguang; Beisser, Daniela; Frohme, Marcus; Schill, Ralph O.; Dandekar, Thomas

    2009-01-01

    Functional protein clusters and regulatory motifs do not only mediate the unique adaptation of tardigrades against extreme temperature and other harsh environmental conditions, but are important markers to distinguish species and taxonomic units. We show here in detail results of our current comparison between Hypsibius dujardini and Milnesium tardigradum. We found 50 different clusters of sequence similar proteins between both tardigrades of which 10 are tardigrade specific. Proteins of othe...

  13. A high-throughput method to examine protein-nucleotide interactions identifies targets of the bacterial transcriptional regulatory protein fur.

    Science.gov (United States)

    Yu, Chunxiao; Lopez, Carlos A; Hu, Han; Xia, Yu; Freedman, David S; Reddington, Alexander P; Daaboul, George G; Unlü, M Selim; Genco, Caroline Attardo

    2014-01-01

    The Ferric uptake regulatory protein (Fur) is a transcriptional regulatory protein that functions to control gene transcription in response to iron in a number of pathogenic bacteria. In this study, we applied a label-free, quantitative and high-throughput analysis method, Interferometric Reflectance Imaging Sensor (IRIS), to rapidly characterize Fur-DNA interactions in vitro with predicted Fur binding sequences in the genome of Neisseria gonorrhoeae, the causative agent of the sexually transmitted disease gonorrhea. IRIS can easily be applied to examine multiple protein-protein, protein-nucleotide and nucleotide-nucleotide complexes simultaneously and demonstrated here that seventy percent of the predicted Fur boxes in promoter regions of iron-induced genes bound to Fur in vitro with a range of affinities as observed using this microarray screening technology. Combining binding data with mRNA expression levels in a gonococcal fur mutant strain allowed us to identify five new gonococcal genes under Fur-mediated direct regulation.

  14. Regulatory crosstalk by protein kinases on CFTR trafficking and activity

    Science.gov (United States)

    Farinha, Carlos Miguel; Swiatecka-Urban, Agnieszka; Brautigan, David; Jordan, Peter

    2016-01-01

    Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) is a member of the ATP binding cassette (ABC) transporter superfamily that functions as a cAMP-activated chloride ion channel in fluid-transporting epithelia. There is abundant evidence that CFTR activity (i.e. channel opening and closing) is regulated by protein kinases and phosphatases via phosphorylation and dephosphorylation. Here, we review recent evidence for the role of protein kinases in regulation of CFTR delivery to and retention in the plasma membrane. We review this information in a broader context of regulation of other transporters by protein kinases because the overall functional output of transporters involves the integrated control of both their number at the plasma membrane and their specific activity. While many details of the regulation of intracellular distribution of CFTR and other transporters remain to be elucidated, we hope that this review will motivate research providing new insights into how protein kinases control membrane transport to impact health and disease.

  15. RNA-Binding Proteins in Trichomonas vaginalis: Atypical Multifunctional Proteins Involved in a Posttranscriptional Iron Regulatory Mechanism

    Science.gov (United States)

    Figueroa-Angulo, Elisa E.; Calla-Choque, Jaeson S.; Mancilla-Olea, Maria Inocente; Arroyo, Rossana

    2015-01-01

    Iron homeostasis is highly regulated in vertebrates through a regulatory system mediated by RNA-protein interactions between the iron regulatory proteins (IRPs) that interact with an iron responsive element (IRE) located in certain mRNAs, dubbed the IRE-IRP regulatory system. Trichomonas vaginalis, the causal agent of trichomoniasis, presents high iron dependency to regulate its growth, metabolism, and virulence properties. Although T. vaginalis lacks IRPs or proteins with aconitase activity, possesses gene expression mechanisms of iron regulation at the transcriptional and posttranscriptional levels. However, only one gene with iron regulation at the transcriptional level has been described. Recently, our research group described an iron posttranscriptional regulatory mechanism in the T. vaginalis tvcp4 and tvcp12 cysteine proteinase mRNAs. The tvcp4 and tvcp12 mRNAs have a stem-loop structure in the 5'-coding region or in the 3'-UTR, respectively that interacts with T. vaginalis multifunctional proteins HSP70, α-Actinin, and Actin under iron starvation condition, causing translation inhibition or mRNA stabilization similar to the previously characterized IRE-IRP system in eukaryotes. Herein, we summarize recent progress and shed some light on atypical RNA-binding proteins that may participate in the iron posttranscriptional regulation in T. vaginalis. PMID:26703754

  16. Subnuclear organization and trafficking of regulatory proteins: implications for biological control and cancer.

    Science.gov (United States)

    Stein, G S; van Wijnen, A J; Stein, J L; Lian, J B; Montecino, M; Zaidi, K; Javed, A

    2000-01-01

    The regulated and regulatory components that interrelate nuclear structure and function must be experimentally established. A formidable challenge is to define further the control of transcription factor targeting to acceptor sites associated with the nuclear matrix. It will be important to determine whether acceptor proteins are associated with a pre-existing core-filament structural lattice or whether a compositely organized scaffold of regulatory factors is dynamically assembled. An inclusive model for all steps in the targeting of proteins to subnuclear sites cannot yet be proposed. However, this model must account for the apparent diversity of intranuclear targeting signals. It is also important to assess the extent to which regulatory discrimination is mediated by subnuclear domain-specific trafficking signals. Furthermore, the checkpoints that monitor subnuclear distribution of regulatory factors and the sorting steps that ensure both structural and functional fidelity of nuclear domains in which replication and expression of genes occur must be biochemically and mechanistically defined. There is emerging recognition that placement of regulatory components of gene expression must be temporally and spatially coordinated to facilitate biological control. The consequences of breaches in nuclear structure-function relationships are observed in an expanding series of diseases that include cancer [Weis et al., 1994; Rogaia et al., 1997; Yano et al., 1997; Rowley, 1998; Zeng et al., 1998; McNeil et al., 1999; Tao and Levine, 1999a] and neurological disorders [Skinner et al., 1997]. As the repertoire of architecture-associated regulatory factors and cofactors expands, workers in the field are becoming increasingly confident that nuclear organization contributes significantly to control of transcription. To gain increased appreciation for the complexities of subnuclear organization and gene regulation, we must continue to characterize mechanisms that direct

  17. Selective translational control of the Alzheimer amyloid precursor protein transcript by iron regulatory protein-1.

    Science.gov (United States)

    Cho, Hyun-Hee; Cahill, Catherine M; Vanderburg, Charles R; Scherzer, Clemens R; Wang, Bin; Huang, Xudong; Rogers, Jack T

    2010-10-08

    Iron influx increases the translation of the Alzheimer amyloid precursor protein (APP) via an iron-responsive element (IRE) RNA stem loop in its 5'-untranslated region. Equal modulated interaction of the iron regulatory proteins (IRP1 and IRP2) with canonical IREs controls iron-dependent translation of the ferritin subunits. However, our immunoprecipitation RT-PCR and RNA binding experiments demonstrated that IRP1, but not IRP2, selectively bound the APP IRE in human neural cells. This selective IRP1 interaction pattern was evident in human brain and blood tissue from normal and Alzheimer disease patients. We computer-predicted an optimal novel RNA stem loop structure for the human, rhesus monkey, and mouse APP IREs with reference to the canonical ferritin IREs but also the IREs encoded by erythroid heme biosynthetic aminolevulinate synthase and Hif-2α mRNAs, which preferentially bind IRP1. Selective 2'-hydroxyl acylation analyzed by primer extension analysis was consistent with a 13-base single-stranded terminal loop and a conserved GC-rich stem. Biotinylated RNA probes deleted of the conserved CAGA motif in the terminal loop did not bind to IRP1 relative to wild type probes and could no longer base pair to form a predicted AGA triloop. An AGU pseudo-triloop is key for IRP1 binding to the canonical ferritin IREs. RNA probes encoding the APP IRE stem loop exhibited the same high affinity binding to rhIRP1 as occurs for the H-ferritin IRE (35 pm). Intracellular iron chelation increased binding of IRP1 to the APP IRE, decreasing intracellular APP expression in SH-SY5Y cells. Functionally, shRNA knockdown of IRP1 caused increased expression of neural APP consistent with IRP1-APP IRE-driven translation.

  18. THE REGULATORY EFFECT OF NUCLEOSIDE DIPHOSPHATE KINASE ON G-PROTEIN AND G-PROTEIN MEDIATED PHOSPHOLIPASE C

    Institute of Scientific and Technical Information of China (English)

    张德昌; 张宽仁

    1995-01-01

    The effect of nueleoside diphosphate kinase (NDPK) on the activity of guanine nueleotide regulatory protein (G-protein) mediated phospholipase C (PLC) and on the [35S ] GTPTτS binding of G-protein was investigated in this work in order to demonstrate the mechanism behind the regulation of G-protein and its effector PLC by NDPK. The stimulation of PLC in turkey erythrocyte membrane by both GTP and GTPτS indicated that the PLC stimulation was msdiated by G-protein, NDPK alone stimulated PLC activity, as well as the stimulation in the presence of GTP and GDP, in a dose-dependent manner. However, NDPK inhibited GTPτS-stimulated PLC, Furthermore, NDPK inhibited [35S] GTPτS binding of purified Gi-protein in a non-competitive manner. A hypothesis implying an important role of direct interaction of G-protein and NDPK in the regulation of their functions is suggested and discussed.

  19. Contribution of Asparagine Catabolism to Salmonella Virulence.

    Science.gov (United States)

    McLaughlin, Patrick A; McClelland, Michael; Yang, Hee-Jeong; Porwollik, Steffen; Bogomolnaya, Lydia; Chen, Juei-Suei; Andrews-Polymenis, Helene; van der Velden, Adrianus W M

    2017-02-01

    Salmonellae are pathogenic bacteria that cause significant morbidity and mortality in humans worldwide. Salmonellae establish infection and avoid clearance by the immune system by mechanisms that are not well understood. We previously showed that l-asparaginase II produced by Salmonella enterica serovar Typhimurium (S Typhimurium) inhibits T cell responses and mediates virulence. In addition, we previously showed that asparagine deprivation such as that mediated by l-asparaginase II of S Typhimurium causes suppression of activation-induced T cell metabolic reprogramming. Here, we report that STM3997, which encodes a homolog of disulfide bond protein A (dsbA) of Escherichia coli, is required for l-asparaginase II stability and function. Furthermore, we report that l-asparaginase II localizes primarily to the periplasm and acts together with l-asparaginase I to provide S Typhimurium the ability to catabolize asparagine and assimilate nitrogen. Importantly, we determined that, in a murine model of infection, S Typhimurium lacking both l-asparaginase I and II genes competes poorly with wild-type S Typhimurium for colonization of target tissues. Collectively, these results indicate that asparagine catabolism contributes to S Typhimurium virulence, providing new insights into the competition for nutrients at the host-pathogen interface.

  20. Involvement of Phosphatidylinositol 3-kinase in the regulation of proline catabolism in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Anne-Sophie eLeprince

    2015-01-01

    Full Text Available Plant adaptation to abiotic stresses such as drought and salinity involves complex regulatory processes. Deciphering the signalling components that are involved in stress signal transduction and cellular responses is of importance to understand how plants cope with salt stress. Accumulation of osmolytes such as proline is considered to participate in the osmotic adjustment of plant cells to salinity. Proline accumulation results from a tight regulation between its biosynthesis and catabolism. Lipid signal components such as phospholipases C and D have previously been shown to be involved in the regulation of proline metabolism in Arabidopsis thaliana. In this study, we demonstrate that proline metabolism is also regulated by class-III Phosphatidylinositol 3-kinase (PI3K, VPS34, which catalyses the formation of phosphatidylinositol 3-phosphate (PI3P from phosphatidylinositol. Using pharmacological and biochemical approaches, we show that the PI3K inhibitor, LY294002, affects PI3P levels in vivo and that it triggers a decrease in proline accumulation in response to salt treatment of A. thaliana seedlings. The lower proline accumulation is correlated with a lower transcript level of Pyrroline-5-carboxylate synthetase 1 biosynthetic enzyme and higher transcript and protein levels of Proline dehydrogenase 1 (ProDH1, a key-enzyme in proline catabolism. We also found that the ProDH1 expression is induced in a pi3k-hemizygous mutant, further demonstrating that PI3K is involved in the regulation of proline catabolism through transcriptional regulation of ProDH1. A broader metabolomic analysis indicates that LY294002 also reduced other metabolites, such as hydrophobic and aromatic amino acids and sugars like raffinose.

  1. Treatment with alpha-melanocyte stimulating hormone preserves calcium regulatory proteins in rat heart allografts.

    Science.gov (United States)

    Colombo, Gualtiero; Sordi, Andrea; Lonati, Caterina; Carlin, Andrea; Turcatti, Flavia; Leonardi, Patrizia; Gatti, Stefano; Catania, Anna

    2008-08-01

    Prevention of graft dysfunction is a major objective in transplantation medicine. Previous research on experimental heart transplantation indicated that treatment with the immunomodulatory peptide alpha-melanocyte stimulating hormone (alpha-MSH) improves histopathology, prolongs allograft survival, and reduces expression of the main tissue injury mediators. Because calcium-handling is critical in heart graft function, we determined the effects of transplantation injury and influences of alpha-MSH treatment on representative calcium regulatory proteins in rat heart allografts. Hearts from Brown Norway rats were transplanted heterotopically into MHC incompatible Lewis rats. Ca(2+)/calmodulin-dependent protein kinase II (CaMKII), protein kinase C epsilon (PKC epsilon), sarcoplasmic/endoplasmic reticulum calcium-ATPase 2 (SERCA2a), arrestin-beta1 (Arrb1), cholinergic receptor M2 (Chrm2), and inositol 1,4,5-triphosphate receptor 1 (InsP(3)R1) were examined in: (1) non-transplanted donor hearts; (2) allografts from saline-treated rats; and (3) allografts from rats treated with the synthetic alpha-MSH analog Nle4-DPhe7-alpha-MSH (NDP-alpha-MSH) (100 microg i.p. every 12h). Transplantation injury was associated with severe reduction in calcium regulatory protein transcription and expression level. NDP-alpha-MSH administration partly reversed inhibition of protein transcription and almost completely prevented protein loss. Finally, because certain effects of cyclic 3'-5'-adenosine monophosphate (cAMP) signaling on calcium handling in cardiac myocytes depend on activation of exchange protein directly activated by cAMP 1 (Epac1), we determined Epac1 mRNA and protein expression in heart allografts. Transplantation injury markedly reduced Epac1. NDP-alpha-MSH treatment significantly preserved both Epac1 protein and mRNA in the allografts. Administration of alpha-MSH or related melanocortins could reduce transplantation-induced dysfunction through protection of heart calcium

  2. A synthetic biology approach to self-regulatory recombinant protein production in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Dragosits Martin

    2012-03-01

    Full Text Available Abstract Background Recombinant protein production is a process of great industrial interest, with products that range from pharmaceuticals to biofuels. Since high level production of recombinant protein imposes significant stress in the host organism, several methods have been developed over the years to optimize protein production. So far, these trial-and-error techniques have proved laborious and sensitive to process parameters, while there has been no attempt to address the problem by applying Synthetic Biology principles and methods, such as integration of standardized parts in novel synthetic circuits. Results We present a novel self-regulatory protein production system that couples the control of recombinant protein production with a stress-induced, negative feedback mechanism. The synthetic circuit allows the down-regulation of recombinant protein expression through a stress-induced promoter. We used E. coli as the host organism, since it is widely used in recombinant processes. Our results show that the introduction of the self-regulatory circuit increases the soluble/insoluble ratio of recombinant protein at the expense of total protein yield. To further elucidate the dynamics of the system, we developed a computational model that is in agreement with the observed experimental data, and provides insight on the interplay between protein solubility and yield. Conclusion Our work introduces the idea of a self-regulatory circuit for recombinant protein products, and paves the way for processes with reduced external control or monitoring needs. It demonstrates that the library of standard biological parts serves as a valuable resource for initial synthetic blocks that needs to be further refined to be successfully applied in practical problems of biotechnological significance. Finally, the development of a predictive model in conjunction with experimental validation facilitates a better understanding of the underlying dynamics and can be

  3. Dynamic control of the complement system by modulated expression of regulatory proteins.

    Science.gov (United States)

    Thurman, Joshua M; Renner, Brandon

    2011-01-01

    The complement system serves many biological functions, including the eradication of invasive pathogens and the removal of damaged cells and immune-complexes. Uncontrolled complement activation causes injury to host cells, however, so adequate regulation of the system is essential. Control of the complement system is maintained by a group of cell surface and circulating proteins referred to as complement regulatory proteins. The expression of the cell surface complement regulatory proteins varies from tissue to tissue. Furthermore, specific cell types can upregulate or downregulate the expression of these proteins in response to a variety of signals or insults. Altered regulation of the complement regulatory proteins can have important effects on local complement activation. In some circumstances this can be beneficial, such as in the setting of certain infections. In other circumstances, however, this can be a cause of complement-mediated injury of the tissue. A full understanding of the mechanisms by which the complement system is modulated at the local level can have important implications for how we diagnose and treat a wide range of inflammatory diseases.

  4. [Do the variations in water carbon dioxide pressure and PH have an effect on the nature of end products of protein catabolism, ammonia and urea, in the clawed frog Xenopus laevis?].

    Science.gov (United States)

    Dejours, P; Armand, J; Beekenkamp, H

    1991-01-01

    The effects of PCO2 and pH changes in the ambient water on the nitrogen catabolism and the proportions of the excreted nitrogenous end products, ammonia and urea, were studied in the clawed frog, Xenopus laevis, at 24 degrees C. In animals living in artificial fresh water, the exposure to a hypocapnic alkalosis (PCO2 = 0.7 Torr instead of 10 Torr) did not entail any change in the nitrogen catabolism. In animals who lived in a water loaded with NaCl and had therefore a higher oxygen consumption, an intense nitrogen catabolism and a marked ureotelism, the hypocapnic alkalosis seems to have increased the intensity of the nitrogen catabolism. In neither group were there signs of ammonia toxicity.

  5. Phenylbutyrate improves nitrogen disposal via alternative pathway without eliciting an increase in protein breakdown and catabolism in control and ornithine transcarbamylace-deficient patients

    Science.gov (United States)

    Phenylbutyrate (PB) is a drug used in urea cycle disorder patients to elicit alternative pathways for nitrogen disposal. However, PB decreases plasma branched chain amino acid (BCAA) concentrations and prior research suggests that PB may increase leucine oxidation, indicating increased protein degra...

  6. Reduction in the rates of protein and amino acid catabolism to slow down the accumulation of endogenous ammonia: a strategy potentially adopted by mudskippers (Periophthalmodon schlosseri snd Boleophthalmus boddaerti) during aerial exposure in constant darkness.

    Science.gov (United States)

    Lim, C B; Chew, S F; Anderson, P M; Ip, Y K

    2001-05-01

    This study was designed to elucidate the strategies adopted by mudskippers to handle endogenous ammonia during aerial exposure in constant darkness. Under these conditions, specimens exhibited minimal locomotory activity, and the ammonia and urea excretion rates in both Periophthalmodon schlosseri and Boleophthalmus boddaerti decreased significantly. As a consequence, ammonia accumulation occurred in the tissues of both species of mudskipper. A significant increase in urea levels was found in the liver of P. schlosseri after 24h of aerial exposure, but no similar increase was seen in the tissues of B. boddaerti. It is unlikely that these two species of mudskipper detoxified ammonia to urea during aerial exposure since B. boddaerti does not possess a complete ornithine-urea cycle (OUC) and, although all the OUC enzymes were present in P. schlosseri, the activity of carbamoyl phosphate synthetase present in the liver mitochondria was too low to render the OUC functional for ammonia detoxification. Peritoneal injection of 15NH4Cl into P. schlosseri showed that this mudskipper was capable of incorporating some of the labelled ammonia into urea in its liver. However, aerial exposure did not affect this capability and did not induce detoxification of the accumulated ammonia to urea. Mudskippers exposed to terrestrial conditions and constant darkness did, however, show significant decreases in the total free amino acid content in the liver and blood, in the case of P. schlosseri and in the muscle of B. boddaerti. No changes in the alanine or glutamine content of the muscle were found in either species. Analyses of the balance between the reduction in nitrogenous excretion and the increase in nitrogenous accumulation further revealed that these two species of mudskipper were capable of reducing their protein and amino acid catabolic rates. Such adaptations constitute the most efficient way to avoid the build-up of internal ammonia, and would render unnecessary the

  7. Iron regulatory proteins control a mucosal block to intestinal iron absorption.

    Science.gov (United States)

    Galy, Bruno; Ferring-Appel, Dunja; Becker, Christiane; Gretz, Norbert; Gröne, Hermann-Josef; Schümann, Klaus; Hentze, Matthias W

    2013-03-28

    Mammalian iron metabolism is regulated systemically by the hormone hepcidin and cellularly by iron regulatory proteins (IRPs) that orchestrate a posttranscriptional regulatory network. Through ligand-inducible genetic ablation of both IRPs in the gut epithelium of adult mice, we demonstrate that IRP deficiency impairs iron absorption and promotes mucosal iron retention via a ferritin-mediated "mucosal block." We show that IRP deficiency does not interfere with intestinal sensing of body iron loading and erythropoietic iron need, but rather alters the basal expression of the iron-absorption machinery. IRPs thus secure sufficient iron transport across absorptive enterocytes by restricting the ferritin "mucosal block" and define a basal set point for iron absorption upon which IRP-independent systemic regulatory inputs are overlaid.

  8. Iron Regulatory Proteins Control a Mucosal Block to Intestinal Iron Absorption

    Directory of Open Access Journals (Sweden)

    Bruno Galy

    2013-03-01

    Full Text Available Mammalian iron metabolism is regulated systemically by the hormone hepcidin and cellularly by iron regulatory proteins (IRPs that orchestrate a posttranscriptional regulatory network. Through ligand-inducible genetic ablation of both IRPs in the gut epithelium of adult mice, we demonstrate that IRP deficiency impairs iron absorption and promotes mucosal iron retention via a ferritin-mediated “mucosal block.” We show that IRP deficiency does not interfere with intestinal sensing of body iron loading and erythropoietic iron need, but rather alters the basal expression of the iron-absorption machinery. IRPs thus secure sufficient iron transport across absorptive enterocytes by restricting the ferritin “mucosal block” and define a basal set point for iron absorption upon which IRP-independent systemic regulatory inputs are overlaid.

  9. Intact pituitary function is decisive for the catabolic response to TNF-α - studies of protein, glucose and fatty acid metabolism in hypopituitary and healthy subjects

    DEFF Research Database (Denmark)

    Bach, Ermina; Møller, Andreas Buch; Jørgensen, Jens Otto Lunde

    2015-01-01

    Context: TNF-α generates inflammatory responses and insulin resistance, lipolysis and protein breakdown. It is unclear whether these changes depend on intact hypothalamo-pituitary stress hormone responses triggering release of cortisol and growth hormone. Objective: To define differential effects......-α on lipase expression or regulation in fat. Conclusions: TNF-α increased both urea and amino acid fluxes and EGP significantly more in CTR compared to HP, suggesting that increases in endogenous cortisol and GH release are significant components of the metabolic response to TNF-α....... of TNF-α on glucose, protein and lipid metabolism in hypopituitary patients (without intact hypothalamo-pituitary axis) and healthy controls. Design: Randomized, placebo controlled, single-blinded. Setting, participants and intervention: We studied eight hypopituitary patients(HP) and eight matched...

  10. Membrane-bound complement regulatory proteins as biomarkers and potential therapeutic targets for SLE.

    Science.gov (United States)

    Das, Nibhriti; Biswas, Bintili; Khera, Rohan

    2013-01-01

    For the last two decades, there had been remarkable advancement in understanding the role of complement regulatory proteins in autoimmune disorders and importance of complement inhibitors as therapeutics. Systemic lupus erythematosus is a prototype of systemic autoimmune disorders. The disease, though rare, is potentially fatal and afflicts women at their reproductive age. It is a complex disease with multiorgan involvement, and each patient presents with a different set of symptoms. The diagnosis is often difficult and is based on the diagnostic criteria set by the American Rheumatology Association. Presence of antinuclear antibodies and more specifically antidouble-stranded DNA indicates SLE. Since the disease is multifactorial and its phenotypes are highly heterogeneous, there is a need to identify multiple noninvasive biomarkers for SLE. Lack of validated biomarkers for SLE disease activity or response to treatment is a barrier to the efficient management of the disease, drug discovery, as well as development of new therapeutics. Recent studies with gene knockout mice have suggested that membrane-bound complement regulatory proteins (CRPs) may critically determine the sensitivity of host tissues to complement injury in autoimmune and inflammatory disorders. Case-controlled and followup studies carried out in our laboratory suggest an intimate relation between the level of DAF, MCP, CR1, and CD59 transcripts and the disease activity in SLE. Based on comparative evaluation of our data on these four membrane-bound complement regulatory proteins, we envisaged CR1 and MCP transcripts as putative noninvasive disease activity markers and the respective proteins as therapeutic targets for SLE. Following is a brief appraisal on membrane-bound complement regulatory proteins DAF, MCP, CR1, and CD59 as biomarkers and therapeutic targets for SLE.

  11. Divisome and segrosome components of Deinococcus radiodurans interact through cell division regulatory proteins.

    Science.gov (United States)

    Maurya, Ganesh K; Modi, Kruti; Misra, Hari S

    2016-08-01

    The Deinococcus radiodurans genome encodes many of the known components of divisome as well as four sets of genome partitioning proteins, ParA and ParB on its multipartite genome. Interdependent regulation of cell division and genome segregation is not understood. In vivo interactions of D. radiodurans' sdivisome, segrosome and other cell division regulatory proteins expressed on multicopy plasmids were studied in Escherichia coli using a bacterial two-hybrid system and confirmed by co-immunoprecipitation with the proteins made in E. coli. Many of these showed interactions both with the self and with other proteins. For example, DrFtsA, DrFtsZ, DrMinD, DrMinC, DrDivIVA and all four ParB proteins individually formed at least homodimers, while DrFtsA interacted with DrFtsZ, DrFtsW, DrFtsE, DrFtsK and DrMinD. DrMinD also showed interaction with DrFtsW, DrFtsE and DrMinC. Interestingly, septum site determining protein, DrDivIVA showed interactions with secondary genome ParAs as well as ParB1, ParB3 and ParB4 while DrMinC interacted with ParB1 and ParB3. PprA, a pleiotropic protein recently implicated in cell division regulation, neither interacted with divisome proteins nor ParBs but interacted at different levels with all four ParAs. These results suggest the formation of independent multiprotein complexes of 'DrFts' proteins, segrosome proteins and cell division regulatory proteins, and these complexes could interact with each other through DrMinC and DrDivIVA, and PprA in D. radiodurans.

  12. The Atg1-Tor pathway regulates yolk catabolism in Drosophila embryos.

    Science.gov (United States)

    Kuhn, Hallie; Sopko, Richelle; Coughlin, Margaret; Perrimon, Norbert; Mitchison, Tim

    2015-11-15

    Yolk provides an important source of nutrients during the early development of oviparous organisms. It is composed mainly of vitellogenin proteins packed into membrane-bound compartments called yolk platelets. Catabolism of yolk is initiated by acidification of the yolk platelet, leading to the activation of Cathepsin-like proteinases, but it is unknown how this process is triggered. Yolk catabolism initiates at cellularization in Drosophila melanogaster embryos. Using maternal shRNA technology we found that yolk catabolism depends on the Tor pathway and on the autophagy-initiating kinase Atg1. Whereas Atg1 was required for a burst of spatially regulated autophagy during late cellularization, autophagy was not required for initiating yolk catabolism. We propose that the conserved Tor metabolic sensing pathway regulates yolk catabolism, similar to Tor-dependent metabolic regulation on the lysosome.

  13. Bone marrow: its contribution to heme catabolism.

    Science.gov (United States)

    Mähönen, Y; Anttinen, M; Vuopio, P; Tenhunen, R

    1976-01-01

    Heme oxygenase (HO) and biliverdin reductase (BR), the two NADPH-dependent enzymes involved in the degradation of hemoglobin and its derivatives, were measured in bone marrow aspirates from 5 hematologically normal persons, 4 patients with chronic leucemia (CL), 11 patients with acute leucemia (AL), 8 patients with refractory sideroblastic anemia (RA), 7 patients with iron-deficiency anemia (IA), 5 patients with hemolytic anemia (HA), and 7 patients with secondary anemia (SA) to determine the enzymatic capacity of the bone marrow in different hematologic disorders for heme catabolism. HO activity in the bone marrow of normal persons was 0.42 +/- 0.28 (SD) nmoles bilirubin/10 mg protein/min; in CL, 2.15 +/- 1.34; in AL, 0.39 +/- 0.25; in RA, 0.58 +/- 0.37; in IA, 0.41 +/- 0.28; in HA, 2.56 +/- 1.40; and in SA, 1.72 +/- 1.06. BR activity, respectively, was in normal persons 8.7 +/- 2.4 (SD) nmoles bilirubin/10 mg protein/min; in CL, 13.6 +/- 9.1; in AL, 3.8 +/- 3.1 in RA, 5.1 +/- 2.7; in IA, 5.5 +/- 3.7; in HA, 17.0 +/- 7.2; and in SA, 10.5 +/- 4.2. On the basis of these findings it seems evident that both oxygenase and biliverdin reductase activities of the bone marrow are capable of adaptive regulation. The physiologic role of bone marrow in heme catabolism seems to be of significant importance.

  14. DNA-protein interaction at erythroid important regulatory elements of MEL cells by in vivo footprinting

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Using ligation-mediated PCR method to study the status of DNA-protein interaction at hypersensitive site 2 of locus control Region and β maj promoter of MEL cell line before and after induction, MEL cell has been cultured and induced to differentiation by Hemin and DMSO, then the live cells have been treated with dimethyl sulfate. Ligation mediated PCR has been carried out following the chemical cleavage. The results demonstrate that before and after induction, the status of DNA-protein interaction at both hypersensitive site 2 and β maj promoter change significantly, indicating that distal regulatory elements (locus control region, hypersensitive sites) as well as proximal regulatory elements (promoter, enhancer) of β -globin gene cluster participate in the regulation of developmental specificity.

  15. Overexpression of KH-type splicing regulatory protein regulates proliferation, migration, and implantation ability of osteosarcoma

    Science.gov (United States)

    Pruksakorn, Dumnoensun; Teeyakasem, Pimpisa; Klangjorhor, Jeerawan; Chaiyawat, Parunya; Settakorn, Jongkolnee; Diskul-Na-Ayudthaya, Penchatr; Chokchaichamnankit, Daranee; Pothacharoen, Peraphan; Srisomsap, Chantragan

    2016-01-01

    Osteosarcoma is a common malignant bone tumor in children and adolescents. The current 5-year survival rate is ~60% and that seems to be reaching a plateau. In order to improve treatment outcomes of osteosarcoma, a better understanding of tumorigenesis and underlying molecular mechanisms is required for searching out possible new treatment targets. This study aimed to identify the potential proteins involving the pathogenesis of osteosarcoma using a proteomics approach. Proteins extracted from primary cell culture of osteosarcoma (n=7) and osteoblasts of cancellous bone (n=7) were studied. Using 2-DE based proteomics and LC-MS/MS analysis, we successfully determined seven differentially expressed protein spots. Four upregulated proteins and three downregulated proteins were observed in this study in which KH-type splicing regulatory protein (KSRP) was selected for further exploration. KSRP was significantly upregulated in osteosarcoma cells compared to osteoblasts using western blot assay. In addition, immunohistochemistry demonstrated that KSRP was also highly expressed in osteosarcoma tissue of independent cases from the experimental group. More importantly, KSRP silencing of osteosarcoma cell lines significantly decreased cell proliferation, migration ability, as well as implantation and growth ability in chick chorioallantoic membrane assay. Taken together, these findings demonstrate, that KSRP plays important roles in regulatory controls of osteosarcoma pathogenesis and serves as a potentially therapeutic target of osteosarcoma. PMID:27573585

  16. Structural studies of bacterial transcriptional regulatory proteins by multidimensional heteronuclear NMR

    Energy Technology Data Exchange (ETDEWEB)

    Volkman, B.F.

    1995-02-01

    Nuclear magnetic resonance spectroscopy was used to elucidate detailed structural information for peptide and protein molecules. A small peptide was designed and synthesized, and its three-dimensional structure was calculated using distance information derived from two-dimensional NMR measurements. The peptide was used to induce antibodies in mice, and the cross-reactivity of the antibodies with a related protein was analyzed with enzyme-linked immunosorbent assays. Two proteins which are involved in regulation of transcription in bacteria were also studied. The ferric uptake regulation (Fur) protein is a metal-dependent repressor which controls iron uptake in bacteria. Two- and three-dimensional NMR techniques, coupled with uniform and selective isotope labeling allowed the nearly complete assignment of the resonances of the metal-binding domain of the Fur protein. NTRC is a transcriptional enhancer binding protein whose N-terminal domain is a {open_quote}receiver domain{close_quote} in the family of {open_quote}two-component{close_quote} regulatory systems. Phosphorylation of the N-terminal domain of NTRC activates the initiation of transcription of aeries encoding proteins involved in nitrogen regulation. Three- and four-dimensional NMR spectroscopy methods have been used to complete the resonance assignments and determine the solution structure of the N-terminal receiver domain of the NTRC protein. Comparison of the solution structure of the NTRC receiver domain with the crystal structures of the homologous protein CheY reveals a very similar fold, with the only significant difference being the position of helix 4 relative to the rest of the protein. The determination of the structure of the NTRC receiver domain is the first step toward understanding a mechanism of signal transduction which is common to many bacterial regulatory systems.

  17. A high-throughput method to examine protein-nucleotide interactions identifies targets of the bacterial transcriptional regulatory protein fur.

    Directory of Open Access Journals (Sweden)

    Chunxiao Yu

    Full Text Available The Ferric uptake regulatory protein (Fur is a transcriptional regulatory protein that functions to control gene transcription in response to iron in a number of pathogenic bacteria. In this study, we applied a label-free, quantitative and high-throughput analysis method, Interferometric Reflectance Imaging Sensor (IRIS, to rapidly characterize Fur-DNA interactions in vitro with predicted Fur binding sequences in the genome of Neisseria gonorrhoeae, the causative agent of the sexually transmitted disease gonorrhea. IRIS can easily be applied to examine multiple protein-protein, protein-nucleotide and nucleotide-nucleotide complexes simultaneously and demonstrated here that seventy percent of the predicted Fur boxes in promoter regions of iron-induced genes bound to Fur in vitro with a range of affinities as observed using this microarray screening technology. Combining binding data with mRNA expression levels in a gonococcal fur mutant strain allowed us to identify five new gonococcal genes under Fur-mediated direct regulation.

  18. [The effect of extremely low doses of the novel regulatory plant proteins ].

    Science.gov (United States)

    Krasnov, M S; Margasiuk, D V; Iamskov, I A; Iamskova, V P

    2003-01-01

    Searching and study on regulatory proteins, which can keep under control the scope of important processes as like as cell adhesion, proliferation, differentiation and morphogenesis, is an actual aim of the current biochemistry. Recently we have identified S-100 proteins in plants of following species: plantain (Plantago major L.), aloe (Aloe arborescens L.), and bilberry (Vaccinum myrtillus L.). Extraction and purification of S-100 proteins gotten from these plants were performed by the method we developed earlier for adhesion proteins of animal tissues. Homogeneity of the studied plant proteins was evaluated and confirmed by HPLC and SDS-electrophoresis in PAAG. Both, plant and animal proteins have appeared to be biologically active at extremely low doses. The tests were performed by adhesiometrical method in short-term tissue culture of mouse's liver in vitro. As a result it was established that the plant proteins insert a membranotropic effect being added in extremely low doses, corresponding to 10(-10)-10(-13) mg/ml. Keeping in mind that the plantain is well known remedy for wound protection and healing, in several experiments we studied the biological effect of plant S-100 proteins on animal cells. It was found that S-100 proteins obtained from plantain influences proliferation of human fibroblasts in vitro. It was found that after the treatment with this protein in low doses the cell growth rate increases essentially.

  19. Inferring Gene Networks for Strains of Dehalococcoides Highlights Conserved Relationships between Genes Encoding Core Catabolic and Cell-Wall Structural Proteins.

    Science.gov (United States)

    Mansfeldt, Cresten B; Heavner, Gretchen W; Rowe, Annette R; Hayete, Boris; Church, Bruce W; Richardson, Ruth E

    2016-01-01

    The interpretation of high-throughput gene expression data for non-model microorganisms remains obscured because of the high fraction of hypothetical genes and the limited number of methods for the robust inference of gene networks. Therefore, to elucidate gene-gene and gene-condition linkages in the bioremediation-important genus Dehalococcoides, we applied a Bayesian inference strategy called Reverse Engineering/Forward Simulation (REFS™) on transcriptomic data collected from two organohalide-respiring communities containing different Dehalococcoides mccartyi strains: the Cornell University mixed community D2 and the commercially available KB-1® bioaugmentation culture. In total, 49 and 24 microarray datasets were included in the REFS™ analysis to generate an ensemble of 1,000 networks for the Dehalococcoides population in the Cornell D2 and KB-1® culture, respectively. Considering only linkages that appeared in the consensus network for each culture (exceeding the determined frequency cutoff of ≥ 60%), the resulting Cornell D2 and KB-1® consensus networks maintained 1,105 nodes (genes or conditions) with 974 edges and 1,714 nodes with 1,455 edges, respectively. These consensus networks captured multiple strong and biologically informative relationships. One of the main highlighted relationships shared between these two cultures was a direct edge between the transcript encoding for the major reductive dehalogenase (tceA (D2) or vcrA (KB-1®)) and the transcript for the putative S-layer cell wall protein (DET1407 (D2) or KB1_1396 (KB-1®)). Additionally, transcripts for two key oxidoreductases (a [Ni Fe] hydrogenase, Hup, and a protein with similarity to a formate dehydrogenase, "Fdh") were strongly linked, generalizing a strong relationship noted previously for Dehalococcoides mccartyi strain 195 to multiple strains of Dehalococcoides. Notably, the pangenome array utilized when monitoring the KB-1® culture was capable of resolving signals from multiple

  20. Inferring Gene Networks for Strains of Dehalococcoides Highlights Conserved Relationships between Genes Encoding Core Catabolic and Cell-Wall Structural Proteins

    Science.gov (United States)

    Mansfeldt, Cresten B.; Heavner, Gretchen W.; Rowe, Annette R.; Hayete, Boris; Church, Bruce W.; Richardson, Ruth E.

    2016-01-01

    The interpretation of high-throughput gene expression data for non-model microorganisms remains obscured because of the high fraction of hypothetical genes and the limited number of methods for the robust inference of gene networks. Therefore, to elucidate gene-gene and gene-condition linkages in the bioremediation-important genus Dehalococcoides, we applied a Bayesian inference strategy called Reverse Engineering/Forward Simulation (REFS™) on transcriptomic data collected from two organohalide-respiring communities containing different Dehalococcoides mccartyi strains: the Cornell University mixed community D2 and the commercially available KB-1® bioaugmentation culture. In total, 49 and 24 microarray datasets were included in the REFS™ analysis to generate an ensemble of 1,000 networks for the Dehalococcoides population in the Cornell D2 and KB-1® culture, respectively. Considering only linkages that appeared in the consensus network for each culture (exceeding the determined frequency cutoff of ≥ 60%), the resulting Cornell D2 and KB-1® consensus networks maintained 1,105 nodes (genes or conditions) with 974 edges and 1,714 nodes with 1,455 edges, respectively. These consensus networks captured multiple strong and biologically informative relationships. One of the main highlighted relationships shared between these two cultures was a direct edge between the transcript encoding for the major reductive dehalogenase (tceA (D2) or vcrA (KB-1®)) and the transcript for the putative S-layer cell wall protein (DET1407 (D2) or KB1_1396 (KB-1®)). Additionally, transcripts for two key oxidoreductases (a [Ni Fe] hydrogenase, Hup, and a protein with similarity to a formate dehydrogenase, “Fdh”) were strongly linked, generalizing a strong relationship noted previously for Dehalococcoides mccartyi strain 195 to multiple strains of Dehalococcoides. Notably, the pangenome array utilized when monitoring the KB-1® culture was capable of resolving signals from

  1. Proteomic shifts in embryonic stem cells with gene dose modifications suggest the presence of balancer proteins in protein regulatory networks.

    Directory of Open Access Journals (Sweden)

    Lei Mao

    Full Text Available Large numbers of protein expression changes are usually observed in mouse models for neurodegenerative diseases, even when only a single gene was mutated in each case. To study the effect of gene dose alterations on the cellular proteome, we carried out a proteomic investigation on murine embryonic stem cells that either overexpressed individual genes or displayed aneuploidy over a genomic region encompassing 14 genes. The number of variant proteins detected per cell line ranged between 70 and 110, and did not correlate with the number of modified genes. In cell lines with single gene mutations, up and down-regulated proteins were always in balance in comparison to parental cell lines regarding number as well as concentration of differentially expressed proteins. In contrast, dose alteration of 14 genes resulted in an unequal number of up and down-regulated proteins, though the balance was kept at the level of protein concentration. We propose that the observed protein changes might partially be explained by a proteomic network response. Hence, we hypothesize the existence of a class of "balancer" proteins within the proteomic network, defined as proteins that buffer or cushion a system, and thus oppose multiple system disturbances. Through database queries and resilience analysis of the protein interaction network, we found that potential balancer proteins are of high cellular abundance, possess a low number of direct interaction partners, and show great allelic variation. Moreover, balancer proteins contribute more heavily to the network entropy, and thus are of high importance in terms of system resilience. We propose that the "elasticity" of the proteomic regulatory network mediated by balancer proteins may compensate for changes that occur under diseased conditions.

  2. Lanosterol metabolism and sterol regulatory element binding protein (SREBP) expression in male germ cell maturation.

    Science.gov (United States)

    Fon Tacer, Klementina; Kalanj-Bognar, Svjetlana; Waterman, Michael R; Rozman, Damjana

    2003-06-01

    Expression of genes involved in cholesterol biosynthesis in male germ cells is insensitive to the negative cholesterol feedback regulation, in contrast to cholesterol level-sensitive/sterol regulatory element binding protein (SREBP)-dependent gene regulation in somatic cells. The role of sterol regulatory element binding proteins in spermatogenic cells was an enigma until recently, when a soluble, 55kDa cholesterol-insensitive form of SREBP2 (SREBP2gc) was discovered [Mol. Cell. Endocrinol. 22 (2002) 8478], being translated from a germ cell-specific SREBP2 mRNA. Our RT-PCR results also show that SREBP2 as well as SREBP1c mRNAs are detectable in prepubertal and postpubertal male germ cells while SREBP1a is not detected. Surprisingly, three SREBP2 immunoreactive proteins (72, 63 and 55kDa), that are not present in mouse liver nuclei, reside in testis nuclei of prepubertal and adult mice. The 55kDa protein is likely SREBP2gc, the other two isoforms are novel. HPLC measurements in liver and testes of fasted prepubertal and postpubertal mice showed no significant difference in cholesterol level. However, FF-MAS and lanosterol/testis-meiosis activating sterol (T-MAS) intermediates that are detectable mainly in testes, increase in fasted postpubertal mice which coincides well with the elevated level of 68kDa SREBP2. Similar to SREBP2gc, the two novel SREBP2 immunoreactive proteins seem to be insensitive to the level of cholesterol.

  3. Anaerobic catabolism of aromatic compounds: a genetic and genomic view.

    Science.gov (United States)

    Carmona, Manuel; Zamarro, María Teresa; Blázquez, Blas; Durante-Rodríguez, Gonzalo; Juárez, Javier F; Valderrama, J Andrés; Barragán, María J L; García, José Luis; Díaz, Eduardo

    2009-03-01

    Aromatic compounds belong to one of the most widely distributed classes of organic compounds in nature, and a significant number of xenobiotics belong to this family of compounds. Since many habitats containing large amounts of aromatic compounds are often anoxic, the anaerobic catabolism of aromatic compounds by microorganisms becomes crucial in biogeochemical cycles and in the sustainable development of the biosphere. The mineralization of aromatic compounds by facultative or obligate anaerobic bacteria can be coupled to anaerobic respiration with a variety of electron acceptors as well as to fermentation and anoxygenic photosynthesis. Since the redox potential of the electron-accepting system dictates the degradative strategy, there is wide biochemical diversity among anaerobic aromatic degraders. However, the genetic determinants of all these processes and the mechanisms involved in their regulation are much less studied. This review focuses on the recent findings that standard molecular biology approaches together with new high-throughput technologies (e.g., genome sequencing, transcriptomics, proteomics, and metagenomics) have provided regarding the genetics, regulation, ecophysiology, and evolution of anaerobic aromatic degradation pathways. These studies revealed that the anaerobic catabolism of aromatic compounds is more diverse and widespread than previously thought, and the complex metabolic and stress programs associated with the use of aromatic compounds under anaerobic conditions are starting to be unraveled. Anaerobic biotransformation processes based on unprecedented enzymes and pathways with novel metabolic capabilities, as well as the design of novel regulatory circuits and catabolic networks of great biotechnological potential in synthetic biology, are now feasible to approach.

  4. Cytoplasmic dynein and its regulatory proteins in Golgi pathology in nervous system disorders

    Directory of Open Access Journals (Sweden)

    Dick eJaarsma

    2015-10-01

    Full Text Available The Golgi apparatus is a dynamic organelle involved in processing and sorting of lipids and proteins. In neurons, the Golgi apparatus is important for the development of axons and dendrites and maintenance of their highly polarized morphology. The motor protein complex cytoplasmic dynein has an important role in Golgi apparatus positioning and function. Together with dynactin and other regulatory factors it drives microtubule minus-end directed motility of Golgi membranes. Inhibition of dynein results in fragmentation and dispersion of the Golgi ribbon in the neuronal cell body, resembling the Golgi abnormalities observed in some neurodegenerative disorders, in particular motor neuron diseases. Mutations in dynein and its regulatory factors, including the dynactin subunit p150Glued, BICD2 and Lis-1, are associated with several human nervous system disorders, including cortical malformation and motor neuropathy. Here we review the role of dynein and its regulatory factors in Golgi function and positioning, and the potential role of dynein malfunction in causing Golgi apparatus abnormalities in nervous system disorders.

  5. RNA regulatory networks diversified through curvature of the PUF protein scaffold.

    Science.gov (United States)

    Wilinski, Daniel; Qiu, Chen; Lapointe, Christopher P; Nevil, Markus; Campbell, Zachary T; Tanaka Hall, Traci M; Wickens, Marvin

    2015-09-14

    Proteins bind and control mRNAs, directing their localization, translation and stability. Members of the PUF family of RNA-binding proteins control multiple mRNAs in a single cell, and play key roles in development, stem cell maintenance and memory formation. Here we identified the mRNA targets of a S. cerevisiae PUF protein, Puf5p, by ultraviolet-crosslinking-affinity purification and high-throughput sequencing (HITS-CLIP). The binding sites recognized by Puf5p are diverse, with variable spacer lengths between two specific sequences. Each length of site correlates with a distinct biological function. Crystal structures of Puf5p-RNA complexes reveal that the protein scaffold presents an exceptionally flat and extended interaction surface relative to other PUF proteins. In complexes with RNAs of different lengths, the protein is unchanged. A single PUF protein repeat is sufficient to induce broadening of specificity. Changes in protein architecture, such as alterations in curvature, may lead to evolution of mRNA regulatory networks.

  6. The D-galacturonic acid catabolic pathway in Botrytis cinerea.

    Science.gov (United States)

    Zhang, Lisha; Thiewes, Harry; van Kan, Jan A L

    2011-10-01

    D-galacturonic acid is the most abundant component of pectin, one of the major polysaccharide constituents of plant cell walls. Galacturonic acid potentially is an important carbon source for microorganisms living on (decaying) plant material. A catabolic pathway was proposed in filamentous fungi, comprising three enzymatic steps, involving D-galacturonate reductase, L-galactonate dehydratase, and 2-keto-3-deoxy-L-galactonate aldolase. We describe the functional, biochemical and genetic characterization of the entire D-galacturonate-specific catabolic pathway in the plant pathogenic fungus Botrytis cinerea. The B. cinerea genome contains two non-homologous galacturonate reductase genes (Bcgar1 and Bcgar2), a galactonate dehydratase gene (Bclgd1), and a 2-keto-3-deoxy-L-galactonate aldolase gene (Bclga1). Their expression levels were highly induced in cultures containing GalA, pectate, or pectin as the sole carbon source. The four proteins were expressed in Escherichia coli and their enzymatic activity was characterized. Targeted gene replacement of all four genes in B. cinerea, either separately or in combinations, yielded mutants that were affected in growth on D-galacturonic acid, pectate, or pectin as the sole carbon source. In Aspergillus nidulans and A. niger, the first catabolic conversion only involves the Bcgar2 ortholog, while in Hypocrea jecorina, it only involves the Bcgar1 ortholog. In B. cinerea, however, BcGAR1 and BcGAR2 jointly contribute to the first step of the catabolic pathway, albeit to different extent. The virulence of all B. cinerea mutants in the D-galacturonic acid catabolic pathway on tomato leaves, apple fruit and bell peppers was unaltered.

  7. Functional homology between the yeast regulatory proteins GAL4 and LAC9: LAC9-mediated transcriptional activation in Kluyveromyces lactis involves protein binding to a regulatory sequence homologous to the GAL4 protein-binding site.

    OpenAIRE

    Breunig, K D; Kuger, P

    1987-01-01

    As shown previously, the beta-galactosidase gene of Kluyveromyces lactis is transcriptionally regulated via an upstream activation site (UASL) which contains a sequence homologous to the GAL4 protein-binding site in Saccharomyces cerevisiae (M. Ruzzi, K.D. Breunig, A.G. Ficca, and C.P. Hollenberg, Mol. Cell. Biol. 7:991-997, 1987). Here we demonstrate that the region of homology specifically binds a K. lactis regulatory protein. The binding activity was detectable in protein extracts from wil...

  8. Structure of dual function iron regulatory protein 1 complexed with ferritin IRE-RNA

    Energy Technology Data Exchange (ETDEWEB)

    Walden, William E.; Selezneva, Anna I.; Dupuy, Jérôme; Volbeda, Anne; Fontecilla-Camps, Juan C.; Theil, Elizabeth C.; Volz1, Karl (IBS); (CHORI); (UIC)

    2011-07-27

    Iron regulatory protein 1 (IRP1) binds iron-responsive elements (IREs) in messenger RNAs (mRNAs), to repress translation or degradation, or binds an iron-sulfur cluster, to become a cytosolic aconitase enzyme. The 2.8 angstrom resolution crystal structure of the IRP1:ferritin H IRE complex shows an open protein conformation compared with that of cytosolic aconitase. The extended, L-shaped IRP1 molecule embraces the IRE stem-loop through interactions at two sites separated by {approx}30 angstroms, each involving about a dozen protein:RNA bonds. Extensive conformational changes related to binding the IRE or an iron-sulfur cluster explain the alternate functions of IRP1 as an mRNA regulator or enzyme.

  9. Role of complement and complement regulatory proteins in the complications of diabetes.

    Science.gov (United States)

    Ghosh, Pamela; Sahoo, Rupam; Vaidya, Anand; Chorev, Michael; Halperin, Jose A

    2015-06-01

    It is well established that the organ damage that complicates human diabetes is caused by prolonged hyperglycemia, but the cellular and molecular mechanisms by which high levels of glucose cause tissue damage in humans are still not fully understood. The prevalent hypothesis explaining the mechanisms that may underlie the pathogenesis of diabetes complications includes overproduction of reactive oxygen species, increased flux through the polyol pathway, overactivity of the hexosamine pathway causing intracellular formation of advanced glycation end products, and activation of protein kinase C isoforms. In addition, experimental and clinical evidence reported in past decades supports a strong link between the complement system, complement regulatory proteins, and the pathogenesis of diabetes complications. In this article, we summarize the body of evidence that supports a role for the complement system and complement regulatory proteins in the pathogenesis of diabetic vascular complications, with specific emphasis on the role of the membrane attack complex (MAC) and of CD59, an extracellular cell membrane-anchored inhibitor of MAC formation that is inactivated by nonenzymatic glycation. We discuss a pathogenic model of human diabetic complications in which a combination of CD59 inactivation by glycation and hyperglycemia-induced complement activation increases MAC deposition, activates pathways of intracellular signaling, and induces the release of proinflammatory, prothrombotic cytokines and growth factors. Combined, complement-dependent and complement-independent mechanisms induced by high glucose promote inflammation, proliferation, and thrombosis as characteristically seen in the target organs of diabetes complications.

  10. EWS and FUS bind a subset of transcribed genes encoding proteins enriched in RNA regulatory functions

    DEFF Research Database (Denmark)

    Luo, Yonglun; Friis, Jenny Blechingberg; Fernandes, Ana Miguel;

    2015-01-01

    IP-seq). Our results show that FUS and EWS bind to a subset of actively transcribed genes, that binding often is downstream the poly(A)-signal, and that binding overlaps with RNA polymerase II. Functional examinations of selected target genes identified that FUS and EWS can regulate gene expression...... at different levels. Gene Ontology analyses showed that FUS and EWS target genes preferentially encode proteins involved in regulatory processes at the RNA level. Conclusions The presented results yield new insights into gene interactions of EWS and FUS and have identified a set of FUS and EWS target genes...

  11. Human Sterol Regulatory Element-Binding Protein 1a Contributes Significantly to Hepatic Lipogenic Gene Expression

    OpenAIRE

    Andreas Bitter; Nüssler, Andreas K.; Thasler, Wolfgang E.; Kathrin Klein; Zanger, Ulrich M.; Matthias Schwab; Oliver Burk

    2015-01-01

    Background/Aims: Sterol regulatory element-binding protein (SREBP) 1, the master regulator of lipogenesis, was shown to be associated with non-alcoholic fatty liver disease, which is attributed to its major isoform SREBP1c. Based on studies in mice, the minor isoform SREBP1a is regarded as negligible for hepatic lipogenesis. This study aims to elucidate the expression and functional role of SREBP1a in human liver. Methods: mRNA expression of both isoforms was quantified in cohorts of human li...

  12. Spatial proximity statistics suggest a regulatory role of protein phosphorylation on compound binding.

    Science.gov (United States)

    Korkuć, Paula; Walther, Dirk

    2016-05-01

    Phosphorylation is an important post-translational modification that regulates protein function by the attachment of negatively charged phosphate groups to phosphorylatable amino acid residues. As a mode of action, an influence of phosphorylation on the binding of compounds to proteins has been discussed and described for a number of proteins in the literature. However, a systematic statistical survey probing for enriched phosphorylation sites close to compound binding sites in support of this notion and with properly chosen random reference distributions has not been presented yet. Using high-resolution protein structures from the Protein Data Bank including their co-crystallized non-covalently bound compounds and experimentally determined phosphorylation sites, we analyzed the pairwise distance distributions of phosphorylation and compound binding sites on protein surfaces. We found that phosphorylation sites are indeed located at significantly closer distances to compounds than expected by chance holding true specifically also for the subset of compound binding sites serving as catalytic sites of metabolic reactions. This tendency was particularly evident when treating phosphorylation sites as collective sets supporting the relevance of phosphorylation hotspots. Interestingly, phosphorylation sites were found to be closer to negatively charged than to positively charged compounds suggesting a stronger modulation of the binding of negatively charged compounds in dependence on phosphorylation status than on positively charged compounds. The enrichment of phosphorylation sites near compound binding sites confirms a regulatory role of phosphorylation in compound binding and provides a solid statistical basis for the literature-reported selected events.

  13. Role of Glucokinase in the Subcellular Localization of Glucokinase Regulatory Protein

    Directory of Open Access Journals (Sweden)

    Ling Jin

    2015-04-01

    Full Text Available Glucokinase (GCK is the rate-limiting enzyme of liver glucose metabolism. Through protein-protein interactions, glucokinase regulatory protein (GCKR post-transcriptionally regulates GCK function in the liver, and causes its nuclear localization. However the role of GCK in regulating GCKR localization is unknown. In the present study, using in vitro and in vivo models, we examined the levels of GCK and GCKR, and their subcellular localization. We found that total cellular levels of GCKR did not vary in the in vivo models, but its subcellular localization did. In animals with normal levels of GCK, GCKR is mainly localized to the nuclei of hepatocytes. In seven-day old rats and liver-specific Gck gene knockout mice (animals that lack or have reduced levels of GCK protein, GCKR was found primarily in the cytoplasm. The interaction of GCK with GCKR was further examined using in vitro models where we varied the levels of GCK and GCKR. Varying the level of GCK protein had no effect on total cellular GCKR protein levels. Taken together, our results indicate that GCK is important for the localization of GCKR to the nucleus and raises the possibility that GCKR may have functions in addition to those regulating GCK activity in the cytoplasm.

  14. Proliferation of transformed somatotroph cells related to low or absent expression of protein kinase a regulatory subunit 1A protein.

    Science.gov (United States)

    Lania, Andrea G; Mantovani, Giovanna; Ferrero, Stefano; Pellegrini, Caterina; Bondioni, Sara; Peverelli, Erika; Braidotti, Paola; Locatelli, Marco; Zavanone, Mario L; Ferrante, Emanuela; Bosari, Silvano; Beck-Peccoz, Paolo; Spada, Anna

    2004-12-15

    The two regulatory subunits (R1 and R2) of protein kinase A (PKA) are differentially expressed in cancer cell lines and exert diverse roles in growth control. Recently, mutations of the PKA regulatory subunit 1A gene (PRKAR1A) have been identified in patients with Carney complex. The aim of this study was to evaluate the expression of the PKA regulatory subunits R1A, R2A, and R2B in a series of 30 pituitary adenomas and the effects of subunit activation on cell proliferation. In these tumors, neither mutation of PRKAR1A nor loss of heterozygosity was identified. By real-time PCR, mRNA of the three subunits was detected in all of the tumors, R1A being the most represented in the majority of samples. By contrast, immunohistochemistry documented low or absent R1A levels in all tumors, whereas R2A and R2B were highly expressed, thus resulting in an unbalanced R1/R2 ratio. The low levels of R1A were, at least in part, due to proteasome-mediated degradation. The effect of the R1/R2 ratio on proliferation was assessed in GH3 cells, which showed a similar unbalanced pattern of R subunits expression, and in growth hormone-secreting adenomas. The R2-selective cAMP analog 8-Cl cAMP and R1A RNA silencing, stimulated cell proliferation and increased Cyclin D1 expression, respectively, in human and rat adenomatous somatotrophs. These data show that a low R1/R2 ratio promoted proliferation of transformed somatotrophs and are consistent with the Carney complex model in which R1A inactivating mutations further unbalance this ratio in favor of R2 subunits. These results suggest that low expression of R1A protein may favor cAMP-dependent proliferation of transformed somatotrophs.

  15. Identification of Functional Regulatory Residues of the β-Lactam Inducible Penicillin Binding Protein in Methicillin-Resistant Staphylococcus aureus

    OpenAIRE

    Mbah, Andreas N.; Isokpehi, Raphael D

    2013-01-01

    Resistance to methicillin by Staphylococcus aureus is a persistent clinical problem worldwide. A mechanism for resistance has been proposed in which methicillin resistant Staphylococcus aureus (MRSA) isolates acquired a new protein called β -lactam inducible penicillin binding protein (PBP-2′). The PBP-2′ functions by substituting other penicillin binding proteins which have been inhibited by β -lactam antibiotics. Presently, there is no structural and regulatory information on PBP-2′ protein...

  16. Protein phosphatase 2A regulatory subunit B56α limits phosphatase activity in the heart.

    Science.gov (United States)

    Little, Sean C; Curran, Jerry; Makara, Michael A; Kline, Crystal F; Ho, Hsiang-Ting; Xu, Zhaobin; Wu, Xiangqiong; Polina, Iuliia; Musa, Hassan; Meadows, Allison M; Carnes, Cynthia A; Biesiadecki, Brandon J; Davis, Jonathan P; Weisleder, Noah; Györke, Sandor; Wehrens, Xander H; Hund, Thomas J; Mohler, Peter J

    2015-07-21

    Protein phosphatase 2A (PP2A) is a serine/threonine-selective holoenzyme composed of a catalytic, scaffolding, and regulatory subunit. In the heart, PP2A activity is requisite for cardiac excitation-contraction coupling and central in adrenergic signaling. We found that mice deficient in the PP2A regulatory subunit B56α (1 of 13 regulatory subunits) had altered PP2A signaling in the heart that was associated with changes in cardiac physiology, suggesting that the B56α regulatory subunit had an autoinhibitory role that suppressed excess PP2A activity. The increase in PP2A activity in the mice with reduced B56α expression resulted in slower heart rates and increased heart rate variability, conduction defects, and increased sensitivity of heart rate to parasympathetic agonists. Increased PP2A activity in B56α(+/-) myocytes resulted in reduced Ca(2+) waves and sparks, which was associated with decreased phosphorylation (and thus decreased activation) of the ryanodine receptor RyR2, an ion channel on intracellular membranes that is involved in Ca(2+) regulation in cardiomyocytes. In line with an autoinhibitory role for B56α, in vivo expression of B56α in the absence of altered abundance of other PP2A subunits decreased basal phosphatase activity. Consequently, in vivo expression of B56α suppressed parasympathetic regulation of heart rate and increased RyR2 phosphorylation in cardiomyocytes. These data show that an integral component of the PP2A holoenzyme has an important inhibitory role in controlling PP2A enzyme activity in the heart.

  17. Mitochondrial fusion and ERK activity regulate steroidogenic acute regulatory protein localization in mitochondria.

    Science.gov (United States)

    Duarte, Alejandra; Castillo, Ana Fernanda; Podestá, Ernesto J; Poderoso, Cecilia

    2014-01-01

    The rate-limiting step in the biosynthesis of steroid hormones, known as the transfer of cholesterol from the outer to the inner mitochondrial membrane, is facilitated by StAR, the Steroidogenic Acute Regulatory protein. We have described that mitochondrial ERK1/2 phosphorylates StAR and that mitochondrial fusion, through the up-regulation of a fusion protein Mitofusin 2, is essential during steroidogenesis. Here, we demonstrate that mitochondrial StAR together with mitochondrial active ERK and PKA are necessary for maximal steroid production. Phosphorylation of StAR by ERK is required for the maintenance of this protein in mitochondria, observed by means of over-expression of a StAR variant lacking the ERK phosphorylation residue. Mitochondrial fusion regulates StAR levels in mitochondria after hormone stimulation. In this study, Mitofusin 2 knockdown and mitochondrial fusion inhibition in MA-10 Leydig cells diminished StAR mRNA levels and concomitantly mitochondrial StAR protein. Together our results unveil the requirement of mitochondrial fusion in the regulation of the localization and mRNA abundance of StAR. We here establish the relevance of mitochondrial phosphorylation events in the correct localization of this key protein to exert its action in specialized cells. These discoveries highlight the importance of mitochondrial fusion and ERK phosphorylation in cholesterol transport by means of directing StAR to the outer mitochondrial membrane to achieve a large number of steroid molecules per unit of StAR.

  18. iTRAQ-Based Quantitative Proteomics Identifies Potential Regulatory Proteins Involved in Chicken Eggshell Brownness

    Science.gov (United States)

    Wu, Guiqin; Shi, Fengying; Liu, Aiqiao; Yang, Ning

    2016-01-01

    Brown eggs are popular in many countries and consumers regard eggshell brownness as an important indicator of egg quality. However, the potential regulatory proteins and detailed molecular mechanisms regulating eggshell brownness have yet to be clearly defined. In the present study, we performed quantitative proteomics analysis with iTRAQ technology in the shell gland epithelium of hens laying dark and light brown eggs to investigate the candidate proteins and molecular mechanisms underlying variation in chicken eggshell brownness. The results indicated 147 differentially expressed proteins between these two groups, among which 65 and 82 proteins were significantly up-regulated in the light and dark groups, respectively. Functional analysis indicated that in the light group, the down-regulated iron-sulfur cluster assembly protein (Iba57) would decrease the synthesis of protoporphyrin IX; furthermore, the up-regulated protein solute carrier family 25 (mitochondrial carrier; adenine nucleotide translocator), member 5 (SLC25A5) and down-regulated translocator protein (TSPO) would lead to increased amounts of protoporphyrin IX transported into the mitochondria matrix to form heme with iron, which is supplied by ovotransferrin protein (TF). In other words, chickens from the light group produce less protoporphyrin IX, which is mainly used for heme synthesis. Therefore, the exported protoporphyrin IX available for eggshell deposition and brownness is reduced in the light group. The current study provides valuable information to elucidate variation of chicken eggshell brownness, and demonstrates the feasibility and sensitivity of iTRAQ-based quantitative proteomics analysis in providing useful insights into the molecular mechanisms underlying brown eggshell pigmentation. PMID:28006025

  19. Malignant mixed Mullerian tumors of the uterus: histopathological evaluation of cell cycle and apoptotic regulatory proteins

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    Senger Jenna-Lynn B

    2010-07-01

    Full Text Available Abstract Aim The aim of our study was to evaluate survival outcomes in malignant mixed Mullerian tumors (MMMT of the uterus with respect to the role of cell cycle and apoptotic regulatory proteins in the carcinomatous and sarcomatous components. Methods 23 cases of uterine MMMT identified from the Saskatchewan Cancer Agency (1970-1999 were evaluated. Immunohistochemical expression of Bad, Mcl-1, bcl-x, bak, mdm2, bax, p16, p21, p53, p27, EMA, Bcl-2, Ki67 and PCNA was correlated with clinico-pathological data including survival outcomes. Results Histopathological examination confirmed malignant epithelial component with homologous (12 cases and heterologous (11 cases sarcomatous elements. P53 was strongly expressed (70-95% in 15 cases and negative in 5 cases. The average survival in the p53+ve cases was 3.56 years as opposed to 8.94 years in p53-ve cases. Overexpression of p16 and Mcl-1 were observed in patients with longer survival outcomes (> 2 years. P16 and p21 were overexpressed in the carcinomatous and sarcomatous elements respectively. Cyclin-D1 was focally expressed only in the carcinomatous elements. Conclusions Our study supports that a cell cycle and apoptotic regulatory protein dysregulation is an important pathway for tumorigenesis and b p53 is an important immunoprognostic marker in MMMT of the uterus.

  20. Physiological and Regulatory Effects of Controlled Overproduction of Five Cold Shock Proteins of Lactococcus lactis MG1363

    NARCIS (Netherlands)

    Wouters, Jeroen A.; Mailhes, Marielle; Rombouts, Frank M.; Vos, Willem M. de; Kuipers, Oscar P.; Abee, Tjakko

    2000-01-01

    The physiological and regulatory effects of overproduction of five cold shock proteins (CSPs) of Lactococcus lactis were studied. CspB, CspD, and CspE could be overproduced at high levels (up to 19% of the total protein), whereas for CspA and CspC limited overproduction (0.3 to 0.5% of the total pro

  1. Pro-protein convertases control the maturation and processing of the iron-regulatory protein, RGMc/hemojuvelin

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    Rotwein Peter

    2008-04-01

    Full Text Available Abstract Background Repulsive guidance molecule c (RGMc or hemojuvelin, a glycosylphosphatidylinositol-linked glycoprotein expressed in liver and striated muscle, plays a central role in systemic iron balance. Inactivating mutations in the RGMc gene cause juvenile hemochromatosis (JH, a rapidly progressing iron storage disorder with severe systemic manifestations. RGMc undergoes complex biosynthetic steps leading to membrane-bound and soluble forms of the protein, including both 50 and 40 kDa single-chain species. Results We now show that pro-protein convertases (PC are responsible for conversion of 50 kDa RGMc to a 40 kDa protein with a truncated COOH-terminus. Unlike related molecules RGMa and RGMb, RGMc encodes a conserved PC recognition and cleavage site, and JH-associated RGMc frame-shift mutants undergo COOH-terminal cleavage only if this site is present. A cell-impermeable peptide PC inhibitor blocks the appearance of 40 kDa RGMc in extra-cellular fluid, as does an engineered mutation in the conserved PC recognition sequence, while the PC furin cleaves 50 kDa RGMc in vitro into a 40 kDa molecule with an intact NH2-terminus. Iron loading reduces release of RGMc from the cell membrane, and diminishes accumulation of the 40 kDa species in cell culture medium. Conclusion Our results define a role for PCs in the maturation of RGMc that may have implications for the physiological actions of this critical iron-regulatory protein.

  2. Regulatory switches for hierarchical use of carbon sources in E. coli

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    Ruth S. Perez-Alfaro

    2014-09-01

    Full Text Available In this work we study the preferential use of carbon sources in the bacterium Escherichia coli. To that end we engineered transcriptional fusions of the reporter gene gfpmut2, downstream of transcription-factor promoters, and analyzed their activity under several conditions. The chosen transcription factors are known to regulate catabolic operons associated to the consumption of alternative sugars. The obtained results indicate the following hierarchical order of sugar preference in this bacterium: glucose > arabinose > sorbitol > galactose. Further dynamical results allowed us to conjecture that this hierarchical behavior might be operated by at least the following three regulatory strategies: 1 the coordinated activation of the corresponding operons by the global regulator catabolic repressor protein (CRP, 2 their asymmetrical responses to specific and unspecific sugars and, 3 the architecture of the associated gene regulatory networks.

  3. Discovery of Novel Splice Variants and Regulatory Mechanisms for Microsomal Triglyceride Transfer Protein in Human Tissues

    Science.gov (United States)

    Suzuki, Takashi; Swift, Larry L.

    2016-01-01

    Microsomal triglyceride transfer protein (MTP) is a unique lipid transfer protein essential for the assembly of triglyceride-rich lipoproteins by the liver and intestine. Previous studies in mice identified a splice variant of MTP with an alternate first exon. Splice variants of human MTP have not been reported. Using PCR approaches we have identified two splice variants in human tissues, which we have named MTP-B and MTP-C. MTP-B has a unique first exon (Ex1B) located 10.5 kb upstream of the first exon (Ex1A) for canonical MTP (MTP-A); MTP-C contains both first exons for MTP-A and MTP-B. MTP-B was found in a number of tissues, whereas MTP-C was prominent in brain and testis. MTP-B does not encode a protein; MTP-C encodes the same protein encoded by MTP-A, although MTP-C translation is strongly inhibited by regulatory elements within its 5′-UTR. Using luciferase assays, we demonstrate that the promoter region upstream of exon 1B is quite adequate to drive expression of MTP. We conclude that alternate splicing plays a key role in regulating cellular MTP levels by introducing distinct promoter regions and unique 5′-UTRs, which contain elements that alter translation efficiency, enabling the cell to optimize MTP activity. PMID:27256115

  4. Structural basis for specific recognition of multiple mRNA targets by a PUF regulatory protein

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yeming; Opperman, Laura; Wickens, Marvin; Tanaka Hall, Traci M. (NIH); (UW)

    2011-11-02

    Caenorhabditis elegans fem-3 binding factor (FBF) is a founding member of the PUMILIO/FBF (PUF) family of mRNA regulatory proteins. It regulates multiple mRNAs critical for stem cell maintenance and germline development. Here, we report crystal structures of FBF in complex with 6 different 9-nt RNA sequences, including elements from 4 natural mRNAs. These structures reveal that FBF binds to conserved bases at positions 1-3 and 7-8. The key specificity determinant of FBF vs. other PUF proteins lies in positions 4-6. In FBF/RNA complexes, these bases stack directly with one another and turn away from the RNA-binding surface. A short region of FBF is sufficient to impart its unique specificity and lies directly opposite the flipped bases. We suggest that this region imposes a flattened curvature on the protein; hence, the requirement for the additional nucleotide. The principles of FBF/RNA recognition suggest a general mechanism by which PUF proteins recognize distinct families of RNAs yet exploit very nearly identical atomic contacts in doing so.

  5. Structural basis for specific recognition of multiple mRNA targets by a PUF regulatory protein

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yeming; Opperman, Laura; Wickens, Marvin; Tanaka Hall, Traci M.; (NIH); (UW)

    2010-08-19

    Caenorhabditis elegans fem-3 binding factor (FBF) is a founding member of the PUMILIO/FBF (PUF) family of mRNA regulatory proteins. It regulates multiple mRNAs critical for stem cell maintenance and germline development. Here, we report crystal structures of FBF in complex with 6 different 9-nt RNA sequences, including elements from 4 natural mRNAs. These structures reveal that FBF binds to conserved bases at positions 1-3 and 7-8. The key specificity determinant of FBF vs. other PUF proteins lies in positions 4-6. In FBF/RNA complexes, these bases stack directly with one another and turn away from the RNA-binding surface. A short region of FBF is sufficient to impart its unique specificity and lies directly opposite the flipped bases. We suggest that this region imposes a flattened curvature on the protein; hence, the requirement for the additional nucleotide. The principles of FBF/RNA recognition suggest a general mechanism by which PUF proteins recognize distinct families of RNAs yet exploit very nearly identical atomic contacts in doing so.

  6. Mutations in complement regulatory proteins predispose to preeclampsia: a genetic analysis of the PROMISSE cohort.

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    Jane E Salmon

    2011-03-01

    Full Text Available BACKGROUND: Pregnancy in women with systemic lupus erythematosus (SLE or antiphospholipid antibodies (APL Ab--autoimmune conditions characterized by complement-mediated injury--is associated with increased risk of preeclampsia and miscarriage. Our previous studies in mice indicate that complement activation targeted to the placenta drives angiogenic imbalance and placental insufficiency. METHODS AND FINDINGS: We use PROMISSE, a prospective study of 250 pregnant patients with SLE and/or APL Ab, to test the hypothesis in humans that impaired capacity to limit complement activation predisposes to preeclampsia. We sequenced genes encoding three complement regulatory proteins--membrane cofactor protein (MCP, complement factor I (CFI, and complement factor H (CFH--in 40 patients who had preeclampsia and found heterozygous mutations in seven (18%. Five of these patients had risk variants in MCP or CFI that were previously identified in atypical hemolytic uremic syndrome, a disease characterized by endothelial damage. One had a novel mutation in MCP that impairs regulation of C4b. These findings constitute, to our knowledge, the first genetic defects associated with preeclampsia in SLE and/or APL Ab. We confirmed the association of hypomorphic variants of MCP and CFI in a cohort of non-autoimmune preeclampsia patients in which five of 59 were heterozygous for mutations. CONCLUSION: The presence of risk variants in complement regulatory proteins in patients with SLE and/or APL Ab who develop preeclampsia, as well as in preeclampsia patients lacking autoimmune disease, links complement activation to disease pathogenesis and suggests new targets for treatment of this important public health problem. STUDY REGISTRATION: ClinicalTrials.gov NCT00198068.

  7. Pyridine metabolism in tea plants: salvage, conjugate formation and catabolism.

    Science.gov (United States)

    Ashihara, Hiroshi; Deng, Wei-Wei

    2012-11-01

    Pyridine compounds, including nicotinic acid and nicotinamide, are key metabolites of both the salvage pathway for NAD and the biosynthesis of related secondary compounds. We examined the in situ metabolic fate of [carbonyl-(14)C]nicotinamide, [2-(14)C]nicotinic acid and [carboxyl-(14)C]nicotinic acid riboside in tissue segments of tea (Camellia sinensis) plants, and determined the activity of enzymes involved in pyridine metabolism in protein extracts from young tea leaves. Exogenously supplied (14)C-labelled nicotinamide was readily converted to nicotinic acid, and some nicotinic acid was salvaged to nicotinic acid mononucleotide and then utilized for the synthesis of NAD and NADP. The nicotinic acid riboside salvage pathway discovered recently in mungbean cotyledons is also operative in tea leaves. Nicotinic acid was converted to nicotinic acid N-glucoside, but not to trigonelline (N-methylnicotinic acid), in any part of tea seedlings. Active catabolism of nicotinic acid was observed in tea leaves. The fate of [2-(14)C]nicotinic acid indicates that glutaric acid is a major catabolite of nicotinic acid; it was further metabolised, and carbon atoms were finally released as CO(2). The catabolic pathway observed in tea leaves appears to start with the nicotinic acid N-glucoside formation; this pathway differs from catabolic pathways observed in microorganisms. Profiles of pyridine metabolism in tea plants are discussed.

  8. E6-Associated Protein Dependent Estrogen Receptor Regulation of Protein Kinase A Regulatory Subunit R2A Expression in Neuroblastoma.

    Science.gov (United States)

    Obeid, Jean-Pierre; Zeidan, Youssef H; Zafar, Nawal; El Hokayem, Jimmy

    2017-02-18

    E6ap is a known transcriptional coregulator for estrogen receptor alpha (Er, Erα) in the presence of estrogen. Protein kinase A (PKA) contains two regulatory subunits derived from four genes. Recent evidence demonstrates that PKA regulates E6ap activity. Data generated in our lab indicated estrogen dependent regulation of Pkar2a levels. Our project sets to investigate a possible feedback mechanism constituting of Erα and E6ap transcriptional regulation of Pkar2a expression. Western blot evaluated protein regulation correlations with E2 in mouse neuroblastoma lines. Bioinformatics detected estrogen response element (ERE) sequences. quantitative polymerase chain reaction (qPCR) validated the western blot results. ERE oligonucleotides were synthesized. Reporter gene transcriptional activity was evaluated via Luciferase assay output. Electromobility shift assay (EMSA) assessed direct binding between Erα relevant sequences. Chromatin immunoprecipitation (ChIP) and Re-ChIP were conducted in quantifying protein complex recruitment levels. Pkar2a protein expression directly correlated with E2, and four putative ERE sequences were identified. Pkar2a mRNA expression reverted to baseline with either E2 or E6ap absent. In the presence of E2, ERE-1 and ERE-4 possessed Luciferase reporter gene transcriptional capabilities. ERE-1 portrayed band shifts, representing direct binding to Erα with E2 supplementation. With E2, ERE-1 significantly enhanced Erα and E6ap recruitment levels to the Pkar2a promoter. Pkar2a is directly regulated by Erα and E6ap in the presence of estrogen stimulus. This work indicates a feedback mechanism in the interplay between PKA and E6ap, which may prove crucial for the role of both proteins in cancers and neurogenetic diseases like Angelman syndrome.

  9. Transcriptional control by two leucine-responsive regulatory proteins in Halobacterium salinarum R1

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    Tarasov Valery

    2010-05-01

    Full Text Available Abstract Background Archaea combine bacterial-as well as eukaryotic-like features to regulate cellular processes. Halobacterium salinarum R1 encodes eight leucine-responsive regulatory protein (Lrp-homologues. The function of two of them, Irp (OE3923F and lrpA1 (OE2621R, were analyzed by gene deletion and overexpression, including genome scale impacts using microarrays. Results It was shown that Lrp affects the transcription of multiple target genes, including those encoding enzymes involved in amino acid synthesis, central metabolism, transport processes and other regulators of transcription. In contrast, LrpA1 regulates transcription in a more specific manner. The aspB3 gene, coding for an aspartate transaminase, was repressed by LrpA1 in the presence of L-aspartate. Analytical DNA-affinity chromatography was adapted to high salt, and demonstrated binding of LrpA1 to its own promoter, as well as L-aspartate dependent binding to the aspB3 promoter. Conclusion The gene expression profiles of two archaeal Lrp-homologues report in detail their role in H. salinarum R1. LrpA1 and Lrp show similar functions to those already described in bacteria, but in addition they play a key role in regulatory networks, such as controlling the transcription of other regulators. In a more detailed analysis ligand dependent binding of LrpA1 was demonstrated to its target gene aspB3.

  10. Evolutionary adaptation of an AraC-like regulatory protein in Citrobacter rodentium and Escherichia species.

    Science.gov (United States)

    Tan, Aimee; Petty, Nicola K; Hocking, Dianna; Bennett-Wood, Vicki; Wakefield, Matthew; Praszkier, Judyta; Tauschek, Marija; Yang, Ji; Robins-Browne, Roy

    2015-04-01

    The evolution of pathogenic bacteria is a multifaceted and complex process, which is strongly influenced by the horizontal acquisition of genetic elements and their subsequent expression in their new hosts. A well-studied example is the RegA regulon of the enteric pathogen Citrobacter rodentium. The RegA regulatory protein is a member of the AraC/XylS superfamily, which coordinates the expression of a gene repertoire that is necessary for full pathogenicity of this murine pathogen. Upon stimulation by an exogenous, gut-associated signal, namely, bicarbonate ions, RegA activates the expression of a series of genes, including virulence factors, such as autotransporters, fimbriae, a dispersin-like protein, and the grlRA operon on the locus of enterocyte effacement pathogenicity island. Interestingly, the genes encoding RegA homologues are distributed across the genus Escherichia, encompassing pathogenic and nonpathogenic subtypes. In this study, we carried out a series of bioinformatic, transcriptional, and functional analyses of the RegA regulons of these bacteria. Our results demonstrated that regA has been horizontally transferred to Escherichia spp. and C. rodentium. Comparative studies of two RegA homologues, namely, those from C. rodentium and E. coli SMS-3-5, a multiresistant environmental strain of E. coli, showed that the two regulators acted similarly in vitro but differed in terms of their abilities to activate the virulence of C. rodentium in vivo, which evidently was due to their differential activation of grlRA. Our data indicate that RegA from C. rodentium has strain-specific adaptations that facilitate infection of its murine host. These findings shed new light on the development of virulence by C. rodentium and on the evolution of virulence-regulatory genes of bacterial pathogens in general.

  11. Signal regulatory protein alpha (SIRPalpha cells in the adaptive response to ESAT-6/CFP-10 protein of tuberculous mycobacteria.

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    W Ray Waters

    Full Text Available BACKGROUND: Early secretory antigenic target-6 (ESAT-6 and culture filtrate protein-10 (CFP-10 are co-secreted proteins of Mycobacterium tuberculosis complex mycobacteria (includes M. bovis, the zoonotic agent of bovine tuberculosis involved in phagolysosome escape of the bacillus and, potentially, in the efficient induction of granulomas. Upon tuberculosis infection, multi-nucleate giant cells are elicited, likely as a response aimed at containing mycobacteria. In tissue culture models, signal regulatory protein (SIRPalpha (also referred to as macrophage fusion receptor or CD172a is essential for multi-nucleate giant cell formation. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, ESAT-6/CFP-10 complex and SIRPalpha interactions were evaluated with samples obtained from calves experimentally infected with M. bovis. Peripheral blood CD172a(+ (SIRPalpha-expressing cells from M. bovis-infected calves proliferated upon in vitro stimulation with ESAT-6/CFP-10 (either as a fusion protein or a peptide cocktail, but not with cells from animals receiving M. bovis strains lacking ESAT-6/CFP-10 (i.e, M. bovis BCG or M. bovis DeltaRD1. Sorted CD172a(+ cells from these cultures had a dendritic cell/macrophage morphology, bound fluorescently-tagged rESAT-6:CFP-10, bound and phagocytosed live M. bovis BCG, and co-expressed CD11c, DEC-205, CD44, MHC II, CD80/86 (a subset also co-expressed CD11b or CD8alpha. Intradermal administration of rESAT-6:CFP-10 into tuberculous calves elicited a delayed type hypersensitive response consisting of CD11c(+, CD172a(+, and CD3(+ cells, including CD172a-expressing multi-nucleated giant cells. CONCLUSIONS/SIGNIFICANCE: These findings demonstrate the ability of ESAT-6/CFP-10 to specifically expand CD172a(+ cells, bind to CD172a(+ cells, and induce multi-nucleated giant cells expressing CD172a.

  12. Computational identification of new structured cis-regulatory elements in the 3'-untranslated region of human protein coding genes.

    Science.gov (United States)

    Chen, Xiaowei Sylvia; Brown, Chris M

    2012-10-01

    Messenger ribonucleic acids (RNAs) contain a large number of cis-regulatory RNA elements that function in many types of post-transcriptional regulation. These cis-regulatory elements are often characterized by conserved structures and/or sequences. Although some classes are well known, given the wide range of RNA-interacting proteins in eukaryotes, it is likely that many new classes of cis-regulatory elements are yet to be discovered. An approach to this is to use computational methods that have the advantage of analysing genomic data, particularly comparative data on a large scale. In this study, a set of structural discovery algorithms was applied followed by support vector machine (SVM) classification. We trained a new classification model (CisRNA-SVM) on a set of known structured cis-regulatory elements from 3'-untranslated regions (UTRs) and successfully distinguished these and groups of cis-regulatory elements not been strained on from control genomic and shuffled sequences. The new method outperformed previous methods in classification of cis-regulatory RNA elements. This model was then used to predict new elements from cross-species conserved regions of human 3'-UTRs. Clustering of these elements identified new classes of potential cis-regulatory elements. The model, training and testing sets and novel human predictions are available at: http://mRNA.otago.ac.nz/CisRNA-SVM.

  13. Bioremediation of petroleum hydrocarbons: catabolic genes, microbial communities, and applications.

    Science.gov (United States)

    Fuentes, Sebastián; Méndez, Valentina; Aguila, Patricia; Seeger, Michael

    2014-06-01

    Bioremediation is an environmental sustainable and cost-effective technology for the cleanup of hydrocarbon-polluted soils and coasts. In spite of that longer times are usually required compared with physicochemical strategies, complete degradation of the pollutant can be achieved, and no further confinement of polluted matrix is needed. Microbial aerobic degradation is achieved by the incorporation of molecular oxygen into the inert hydrocarbon molecule and funneling intermediates into central catabolic pathways. Several families of alkane monooxygenases and ring hydroxylating dioxygenases are distributed mainly among Proteobacteria, Actinobacteria, Firmicutes and Fungi strains. Catabolic routes, regulatory networks, and tolerance/resistance mechanisms have been characterized in model hydrocarbon-degrading bacteria to understand and optimize their metabolic capabilities, providing the basis to enhance microbial fitness in order to improve hydrocarbon removal. However, microbial communities taken as a whole play a key role in hydrocarbon pollution events. Microbial community dynamics during biodegradation is crucial for understanding how they respond and adapt to pollution and remediation. Several strategies have been applied worldwide for the recovery of sites contaminated with persistent organic pollutants, such as polycyclic aromatic hydrocarbons and petroleum derivatives. Common strategies include controlling environmental variables (e.g., oxygen availability, hydrocarbon solubility, nutrient balance) and managing hydrocarbon-degrading microorganisms, in order to overcome the rate-limiting factors that slow down hydrocarbon biodegradation.

  14. Systematic identification of regulatory proteins critical for T-cell activation

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    Kolbinger Frank

    2003-09-01

    Full Text Available Abstract Background The activation of T cells, mediated by the T-cell receptor (TCR, activates a battery of specific membrane-associated, cytosolic and nuclear proteins. Identifying the signaling proteins downstream of TCR activation will help us to understand the regulation of immune responses and will contribute to developing therapeutic agents that target immune regulation. Results In an effort to identify novel signaling molecules specific for T-cell activation we undertook a large-scale dominant effector genetic screen using retroviral technology. We cloned and characterized 33 distinct genes from over 2,800 clones obtained in a screen of 7 × 108 Jurkat T cells on the basis of a reduction in TCR-activation-induced CD69 expression after expressing retrovirally derived cDNA libraries. We identified known signaling molecules such as Lck, ZAP70, Syk, PLCγ1 and SHP-1 (PTP1C as truncation mutants with dominant-negative or constitutively active functions. We also discovered molecules not previously known to have functions in this pathway, including a novel protein with a RING domain (found in a class of ubiquitin ligases; we call this protein TRAC-1, transmembrane molecules (EDG1, IL-10Rα and integrin α2, cytoplasmic enzymes and adaptors (PAK2, A-Raf-1, TCPTP, Grb7, SH2-B and GG2-1, and cytoskeletal molecules (moesin and vimentin. Furthermore, using truncated Lck, PLCγ1, EDG1 and PAK2 mutants as examples, we showed that these dominant immune-regulatory molecules interfere with IL-2 production in human primary lymphocytes. Conclusions This study identified important signal regulators in T-cell activation. It also demonstrated a highly efficient strategy for discovering many components of signal transduction pathways and validating them in physiological settings.

  15. The Multifaceted Activity of the VirF Regulatory Protein in the Shigella Lifestyle

    Science.gov (United States)

    Di Martino, Maria Letizia; Falconi, Maurizio; Micheli, Gioacchino; Colonna, Bianca; Prosseda, Gianni

    2016-01-01

    Shigella is a highly adapted human pathogen, mainly found in the developing world and causing a severe enteric syndrome. The highly sophisticated infectious strategy of Shigella banks on the capacity to invade the intestinal epithelial barrier and cause its inflammatory destruction. The cellular pathogenesis and clinical presentation of shigellosis are the sum of the complex action of a large number of bacterial virulence factors mainly located on a large virulence plasmid (pINV). The expression of pINV genes is controlled by multiple environmental stimuli through a regulatory cascade involving proteins and sRNAs encoded by both the pINV and the chromosome. The primary regulator of the virulence phenotype is VirF, a DNA-binding protein belonging to the AraC family of transcriptional regulators. The virF gene, located on the pINV, is expressed only within the host, mainly in response to the temperature transition occurring when the bacterium transits from the outer environment to the intestinal milieu. VirF then acts as anti-H-NS protein and directly activates the icsA and virB genes, triggering the full expression of the invasion program of Shigella. In this review we will focus on the structure of VirF, on its sophisticated regulation, and on its role as major player in the path leading from the non-invasive to the invasive phenotype of Shigella. We will address also the involvement of VirF in mechanisms aimed at withstanding adverse conditions inside the host, indicating that this protein is emerging as a global regulator whose action is not limited to virulence systems. Finally, we will discuss recent observations conferring VirF the potential of a novel antibacterial target for shigellosis. PMID:27747215

  16. The multifaceted activity of the VirF regulatory protein in the Shigella lifestyle

    Directory of Open Access Journals (Sweden)

    Maria Letizia Di Martino

    2016-09-01

    Full Text Available Shigella is a highly adapted human pathogen, mainly found in the developing world and causing a severe enteric syndrome. The highly sophisticated infectious strategy of Shigella banks on the capacity to invade the intestinal epithelial barrier and cause its inflammatory destruction. The cellular pathogenesis and clinical presentation of shigellosis are the sum of the complex action of a large number of bacterial virulence factors mainly located on a large virulence plasmid (pINV. The expression of pINV genes is controlled by multiple environmental stimuli through a regulatory cascade involving proteins and sRNAs encoded by both the pINV and the chromosome. The primary regulator of the virulence phenotype is VirF, a DNA-binding protein belonging to the AraC family of transcriptional regulators. The virF gene, located on the pINV, is expressed only within the host, mainly in response to the temperature transition occurring when the bacterium transits from the outer environment to the intestinal milieu. VirF then acts as anti-H-NS protein and directly activates the icsA and virB genes, triggering the full expression of the invasion program of Shigella. In this review we will focus on the structure of VirF, on its sophisticated regulation, and on its role as major player in the path leading from the non invasive to the invasive phenotype of Shigella. We will address also the involvement of VirF in mechanisms aimed at withstanding adverse conditions inside the host, indicating that this protein is emerging as a global regulator whose action is not limited to virulence systems. Finally, we will discuss recent observations conferring VirF the potential of a novel antibacterial target for shigellosis.

  17. Duck hepatitis B virus expresses a regulatory HBx-like protein from a hidden open reading frame.

    Science.gov (United States)

    Chang, S F; Netter, H J; Hildt, E; Schuster, R; Schaefer, S; Hsu, Y C; Rang, A; Will, H

    2001-01-01

    Duck hepatitis B viruses (DHBV), unlike mammalian hepadnaviruses, are thought to lack X genes, which encode transcription-regulatory proteins believed to contribute to the development of hepatocellular carcinoma. A lack of association of chronic DHBV infection with hepatocellular carcinoma development supports this belief. Here, we demonstrate that DHBV genomes have a hidden open reading frame from which a transcription-regulatory protein, designated DHBx, is expressed both in vitro and in vivo. We show that DHBx enhances neither viral protein expression, intracellular DNA synthesis, nor virion production when assayed in the full-length genome context in LMH cells. However, similar to mammalian hepadnavirus X proteins, DHBx activates cellular and viral promoters via the Raf-mitogen-activated protein kinase signaling pathway and localizes primarily in the cytoplasm. The functional similarities as well as the weak sequence homologies of DHBx and the X proteins of mammalian hepadnaviruses strongly suggest a common ancestry of ortho- and avihepadnavirus X genes. In addition, our data disclose similar intracellular localization and transcription regulatory functions of the corresponding proteins, raise new questions as to their presumed role in hepatocarcinogenesis, and imply unique opportunities for deciphering of their still-enigmatic in vivo functions.

  18. Hypoxia alters cell cycle regulatory protein expression and induces premature maturation of oligodendrocyte precursor cells.

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    Ravi Shankar Akundi

    Full Text Available BACKGROUND: Periventricular white matter injury (PWMI is a common form of brain injury sustained by preterm infants. A major factor that predisposes to PWMI is hypoxia. Because oligodendrocytes (OLs are responsible for myelination of axons, abnormal OL development or function may affect brain myelination. At present our understanding of the influences of hypoxia on OL development is limited. To examine isolated effects of hypoxia on OLs, we examined the influences of hypoxia on OL development in vitro. METHODOLOGY/FINDINGS: Cultures of oligodendrocyte precursor cells (OPCs were prepared from mixed glial cultures and were 99% pure. OPCs were maintained at 21% O(2 or hypoxia (1% or 4% O(2 for up to 7 days. We observed that 1% O(2 lead to an increase in the proportion of myelin basic protein (MBP-positive OLs after 1 week in culture, and a decrease in the proportion of platelet-derived growth factor receptor alpha (PDGFRalpha-positive cells suggesting premature OL maturation. Increased expression of the cell cycle regulatory proteins p27(Kip1 and phospho-cdc2, which play a role in OL differentiation, was seen as well. CONCLUSIONS: These results show that hypoxia interferes with the normal process of OL differentiation by inducing premature OPC maturation.

  19. A mutation in protein phosphatase 2A regulatory subunit A affects auxin transport in Arabidopsis

    Science.gov (United States)

    Garbers, C.; DeLong, A.; Deruere, J.; Bernasconi, P.; Soll, D.; Evans, M. L. (Principal Investigator)

    1996-01-01

    The phytohormone auxin controls processes such as cell elongation, root hair development and root branching. Tropisms, growth curvatures triggered by gravity, light and touch, are also auxin-mediated responses. Auxin is synthesized in the shoot apex and transported through the stem, but the molecular mechanism of auxin transport is not well understood. Naphthylphthalamic acid (NPA) and other inhibitors of auxin transport block tropic curvature responses and inhibit root and shoot elongation. We have isolated a novel Arabidopsis thaliana mutant designated roots curl in NPA (rcn1). Mutant seedlings exhibit altered responses to NPA in root curling and hypocotyl elongation. Auxin efflux in mutant seedlings displays increased sensitivity to NPA. The rcn1 mutation was transferred-DNA (T-DNA) tagged and sequences flanking the T-DNA insert were cloned. Analysis of the RCN1 cDNA reveals that the T-DNA insertion disrupts a gene for the regulatory A subunit of protein phosphatase 2A (PP2A-A). The RCN1 gene rescues the rcn1 mutant phenotype and also complements the temperature-sensitive phenotype of the Saccharomyces cerevisiae PP2A-A mutation, tpd3-1. These data implicate protein phosphatase 2A in the regulation of auxin transport in Arabidopsis.

  20. Unperturbed posttranscriptional regulatory Rev protein function and HIV-1 replication in astrocytes.

    Directory of Open Access Journals (Sweden)

    Ashok Chauhan

    Full Text Available Astrocytes protect neurons, but also evoke proinflammatory responses to injury and viral infections, including HIV. There is a prevailing notion that HIV-1 Rev protein function in astrocytes is perturbed, leading to restricted viral replication. In earlier studies, our finding of restricted viral entry into astrocytes led us to investigate whether there are any intracellular restrictions, including crippled Rev function, in astrocytes. Despite barely detectable levels of DDX3 (Rev-supporting RNA helicase and TRBP (anti-PKR in primary astrocytes compared to astrocytic cells, Rev function was unperturbed in wild-type, but not DDX3-ablated astrocytes. As in permissive cells, after HIV-1 entry bypass in astrocytes, viral-encoded Tat and Rev proteins had robust regulatory activities, leading to efficient viral replication. Productive HIV-1 infection in astrocytes persisted for several weeks. Our findings on HIV-1 entry bypass in astrocytes demonstrated that the intracellular environment is conducive to viral replication and that Tat and Rev functions are unperturbed.

  1. Dynamic localization of glucokinase and its regulatory protein in hypothalamic tanycytes.

    Directory of Open Access Journals (Sweden)

    Magdiel Salgado

    Full Text Available Glucokinase (GK, the hexokinase involved in glucose sensing in pancreatic β cells, is also expressed in hypothalamic tanycytes, which cover the ventricular walls of the basal hypothalamus and are implicated in an indirect control of neuronal activity by glucose. Previously, we demonstrated that GK was preferentially localized in tanycyte nuclei in euglycemic rats, which has been reported in hepatocytes and is suggestive of the presence of the GK regulatory protein, GKRP. In the present study, GK intracellular localization in hypothalamic and hepatic tissues of the same rats under several glycemic conditions was compared using confocal microscopy and Western blot analysis. In the hypothalamus, increased GK nuclear localization was observed in hyperglycemic conditions; however, it was primarily localized in the cytoplasm in hepatic tissue under the same conditions. Both GK and GKRP were next cloned from primary cultures of tanycytes. Expression of GK by Escherichia coli revealed a functional cooperative protein with a S0.5 of 10 mM. GKRP, expressed in Saccharomyces cerevisiae, inhibited GK activity in vitro with a Ki 0.2 µM. We also demonstrated increased nuclear reactivity of both GK and GKRP in response to high glucose concentrations in tanycyte cultures. These data were confirmed using Western blot analysis of nuclear extracts. Results indicate that GK undergoes short-term regulation by nuclear compartmentalization. Thus, in tanycytes, GK can act as a molecular switch to arrest cellular responses to increased glucose.

  2. Innate immunity and protective neuroinflammation: new emphasis on the role of neuroimmune regulatory proteins.

    Science.gov (United States)

    Griffiths, M; Neal, J W; Gasque, P

    2007-01-01

    Brain inflammation due to infection, hemorrhage, and aging is associated with activation of the local innate immune system as expressed by infiltrating cells, resident glial cells, and neurons. The innate immune response relies on the detection of "nonself" and "danger-self" ligands behaving as "eat me signals" by a plethora of pattern recognition receptors (PRRs) expressed by professional and amateur phagocytes to promote the clearance of pathogens, toxic cell debris (amyloid fibrils, aggregated synucleins, prions), and apoptotic cells accumulating within the brain parenchyma and the cerebrospinal fluid (CSF). These PRRs (e.g., complement, TLR, CD14, scavenger receptors) are highly conserved between vertebrates and invertebrates and may represent the most ancestral innate scavenging system involved in tissue homeostasis. However, in some diseases, these protective mechanisms lead to neurodegeneration on the ground that several innate immune molecules have neurocytotoxic activities. The response is a "double-edged sword" representing a fine balance between protective and detrimental effects. Several key regulatory mechanisms have now been evidenced in the control of CNS innate immunity, and these could be harnessed to explore novel therapeutic avenues. We will herein provide new emphasis on the role of neuroimmune regulatory proteins (NIRegs), such as CD95L, TNF, CD200, CD47, sialic acids, CD55, CD46, fH, C3a, HMGB1, which are involved in silencing innate immunity at the cellular and molecular levels and suppression of inflammation. For instance, NIRegs may play an important role in controlling lymphocyte/macrophage/microglia hyperinflammatory responses, while sparing host defense and repair mechanisms. Moreover, NIRegs have direct beneficial effects on neurogenesis and contributing to brain tissue remodeling.

  3. Regulation and evolution of malonate and propionate catabolism in proteobacteria.

    Science.gov (United States)

    Suvorova, I A; Ravcheev, D A; Gelfand, M S

    2012-06-01

    Bacteria catabolize malonate via two pathways, encoded by the mdc and mat genes. In various bacteria, transcription of these genes is controlled by the GntR family transcription factors (TFs) MatR/MdcY and/or the LysR family transcription factor MdcR. Propionate is metabolized via the methylcitrate pathway, comprising enzymes encoded by the prp and acn genes. PrpR, the Fis family sigma 54-dependent transcription factor, is known to be a transcriptional activator of the prp genes. Here, we report a detailed comparative genomic analysis of malonate and propionate metabolism and its regulation in proteobacteria. We characterize genomic loci and gene regulation and identify binding motifs for four new TFs and also new regulon members, in particular, tripartite ATP-independent periplasmic (TRAP) transporters. We describe restructuring of the genomic loci and regulatory interactions during the evolution of proteobacteria.

  4. Adaptation of Tri-molecular fluorescence complementation allows assaying of regulatory Csr RNA-protein interactions in bacteria.

    Science.gov (United States)

    Gelderman, Grant; Sivakumar, Anusha; Lipp, Sarah; Contreras, Lydia

    2015-02-01

    sRNAs play a significant role in controlling and regulating cellular metabolism. One of the more interesting aspects of certain sRNAs is their ability to make global changes in the cell by interacting with regulatory proteins. In this work, we demonstrate the use of an in vivo Tri-molecular Fluorescence Complementation assay to detect and visualize the central regulatory sRNA-protein interaction of the Carbon Storage Regulatory system in E. coli. The Carbon Storage Regulator consists primarily of an RNA binding protein, CsrA, that alters the activity of mRNA targets and of an sRNA, CsrB, that modulates the activity of CsrA. We describe the construction of a fluorescence complementation system that detects the interactions between CsrB and CsrA. Additionally, we demonstrate that the intensity of the fluorescence of this system is able to detect changes in the affinity of the CsrB-CsrA interaction, as caused by mutations in the protein sequence of CsrA. While previous methods have adopted this technique to study mRNA or RNA localization, this is the first attempt to use this technique to study the sRNA-protein interaction directly in bacteria. This method presents a potentially powerful tool to study complex bacterial RNA protein interactions in vivo.

  5. Steroidogenic acute regulatory protein (StAR), a novel mitochondrial cholesterol transporter.

    Science.gov (United States)

    Miller, Walter L

    2007-06-01

    Cholesterol is a vital component of cellular membranes, and is the substrate for biosynthesis of steroids, oxysterols and bile acids. The mechanisms directing the intracellular trafficking of this nearly insoluble molecule have received increased attention through the discovery of the steroidogenic acute regulatory protein (StAR) and similar proteins containing StAR-related lipid transfer (START) domains. StAR can transfer cholesterol between synthetic liposomes in vitro, an activity which appears to correspond to the trans-cytoplasmic transport of cholesterol to mitochondria. However, trans-cytoplasmic cholesterol transport in vivo appears to involve the recently-described protein StarD4, which is expressed in most cells. Steroidogenic cells must also move large amounts of cholesterol from the outer mitochondrial membrane to the first steroidogenic enzyme, which lies on the matrix side of the inner membrane; this action requires StAR. Congenital lipoid adrenal hyperplasia, a rare and severe disorder of human steroidogenesis, results from mutations in StAR, providing a StAR knockout of nature that has provided key insights into its activity. Cell biology experiments show that StAR moves large amounts of cholesterol from the outer to inner mitochondrial membrane, but acts exclusively on the outer membrane. Biophysical data show that only the carboxyl-terminal alpha-helix of StAR interacts with the outer membrane. Spectroscopic data and molecular dynamics simulations show that StAR's interactions with protonated phospholipid head groups on the outer mitochondrial membrane induce a conformational change (molten globule transition) needed for StAR's activity. StAR appears to act in concert with the peripheral benzodiazepine receptor, but the precise itinerary of a cholesterol molecule entering the mitochondrion remains unclear.

  6. Phage phi 29 regulatory protein p4 stabilizes the binding of the RNA polymerase to the late promoter in a process involving direct protein-protein contacts.

    Science.gov (United States)

    Nuez, B; Rojo, F; Salas, M

    1992-12-01

    Transcription from the late promoter, PA3, of Bacillus subtilis phage phi 29 is activated by the viral regulatory protein p4. A kinetic analysis of the activation process has revealed that the role of protein p4 is to stabilize the binding of RNA polymerase to the promoter as a closed complex without significantly affecting further steps of the initiation process. Electrophoretic band-shift assays performed with a DNA fragment spanning only the protein p4 binding site showed that RNA polymerase could efficiently retard the complex formed by protein p4 bound to the DNA. Similarly, when a DNA fragment containing only the RNA polymerase-binding region of PA3 was used, p4 greatly stimulated the binding of RNA polymerase to the DNA. These results strongly suggest that p4 and RNA polymerase contact each other at the PA3 promoter. In the light of current knowledge of the p4 activation mechanism, we propose that direct contacts between the two proteins participate in the activation process.

  7. Catabolism and detoxification of 1-aminoalkylphosphonic acids

    DEFF Research Database (Denmark)

    Hove-Jensen, Bjarne; McSorley, Fern R.; Zechel, David L.

    2012-01-01

    In Escherichia coli uptake and catabolism of organophosphonates are governed by the phnCDEFGHIJKLMNOP operon. The phnO cistron is shown to encode aminoalkylphosphonate N-acetyltransferase, which utilizes acetylcoenzyme A as acetyl donor and aminomethylphosphonate, (S)- and (R)-1-aminoethylphospho...

  8. Regulation of carbon catabolism in Lactococcus lactis.

    NARCIS (Netherlands)

    Aleksandrzak, T; Kowalczyk, M; Kok, J; Bardowski, J; Bielecki, S; Tramper, J; Polak, J

    2000-01-01

    The Lactococcus lactis IL1403 is a lactose negative, plasmid free strain. Nevertheless, it is able to hydrolyze lactose in the presence of cellobiose. In this work we describe identification of a gene involved in this process. The gene was found to be homologous to the sugar catabolism regulator, cc

  9. Identification of Functional Regulatory Residues of the β-Lactam Inducible Penicillin Binding Protein in Methicillin-Resistant Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Andreas N. Mbah

    2013-01-01

    Full Text Available Resistance to methicillin by Staphylococcus aureus is a persistent clinical problem worldwide. A mechanism for resistance has been proposed in which methicillin resistant Staphylococcus aureus (MRSA isolates acquired a new protein called β-lactam inducible penicillin binding protein (PBP-2′. The PBP-2′ functions by substituting other penicillin binding proteins which have been inhibited by β-lactam antibiotics. Presently, there is no structural and regulatory information on PBP-2′ protein. We conducted a complete structural and functional regulatory analysis of PBP-2′ protein. Our analysis revealed that the PBP-2′ is very stable with more hydrophilic amino acids expressing antigenic sites. PBP-2′ has three striking regulatory points constituted by first penicillin binding site at Ser25, second penicillin binding site at Ser405, and finally a single metallic ligand binding site at Glu657 which binds to Zn2+ ions. This report highlights structural features of PBP-2′ that can serve as targets for developing new chemotherapeutic agents and conducting site direct mutagenesis experiments.

  10. Identification of Functional Regulatory Residues of the β -Lactam Inducible Penicillin Binding Protein in Methicillin-Resistant Staphylococcus aureus.

    Science.gov (United States)

    Mbah, Andreas N; Isokpehi, Raphael D

    2013-01-01

    Resistance to methicillin by Staphylococcus aureus is a persistent clinical problem worldwide. A mechanism for resistance has been proposed in which methicillin resistant Staphylococcus aureus (MRSA) isolates acquired a new protein called β -lactam inducible penicillin binding protein (PBP-2'). The PBP-2' functions by substituting other penicillin binding proteins which have been inhibited by β -lactam antibiotics. Presently, there is no structural and regulatory information on PBP-2' protein. We conducted a complete structural and functional regulatory analysis of PBP-2' protein. Our analysis revealed that the PBP-2' is very stable with more hydrophilic amino acids expressing antigenic sites. PBP-2' has three striking regulatory points constituted by first penicillin binding site at Ser25, second penicillin binding site at Ser405, and finally a single metallic ligand binding site at Glu657 which binds to Zn(2+) ions. This report highlights structural features of PBP-2' that can serve as targets for developing new chemotherapeutic agents and conducting site direct mutagenesis experiments.

  11. Expression of steroidogenic acute regulatory protein and its regulation by interferon-gamma in rat corpus luteum

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The steroidogenic acute regulatory protein (StAR) is the key regulatory protein of steroidogenesis. De novo synthesis of StAR protein is required for intramitochondrial translocation of cholesterol to the cytochrome P450 side chain cleavage enzyme which is located on the matrix side of the inner mitochondrial membrane. This is the rate-limiting step of steroid biosynthesis. Using in situ hybridization and immunohistochemistry we studied StAR expression in various stages of the corpora luteal and its regulation by interferon-gamma (IFNγ) in the adult pseudopregnant rat. The results indicated that expression of StAR in the corpora luteal was correlated with progesteron production and IFNγ was capable of inhibiting its expression.

  12. Cross-phosphorylation of bacterial serine/threonine and tyrosine protein kinases on key regulatory residues

    Directory of Open Access Journals (Sweden)

    Lei eShi

    2014-09-01

    Full Text Available Bacteria possess protein serine/threonine and tyrosine kinases which resemble eukaryal kinases in their capacity to phosphorylate multiple substrates. We hypothesized that the analogy might extend further, and bacterial kinases may also undergo mutual phosphorylation and activation, which is currently considered as a hallmark of eukaryal kinase networks. In order to test this hypothesis, we explored the capacity of all members of four different classes of serine/threonine and tyrosine kinases present in the firmicute model organism Bacillus subtilis to phosphorylate each other in vitro and interact with each other in vivo. The interactomics data suggested a high degree of connectivity among all types of kinases, while phosphorylation assays revealed equally wide-spread cross-phosphorylation events. Our findings suggest that the Hanks-type kinases PrkC, PrkD and YabT exhibit the highest capacity to phosphorylate other B. subtilis kinases, while the BY-kinase PtkA and the two-component-like kinases RsbW and SpoIIAB show the highest propensity to be phosphorylated by other kinases. Analysis of phosphorylated residues on several selected recipient kinases suggests that most cross-phosphorylation events concern key regulatory residues. Therefore, cross-phosphorylation events are very likely to influence the capacity of recipient kinases to phosphorylate substrates downstream in the signal transduction cascade. We therefore conclude that bacterial serine/threonine and tyrosine kinases probably engage in a network-type behavior previously described only in eukaryal cells.

  13. Importance of fumarate and nitrate reduction regulatory protein for intestinal proliferation of Vibrio vulnificus.

    Science.gov (United States)

    Kado, Takehiro; Kashimoto, Takashige; Yamazaki, Kohei; Ueno, Shunji

    2017-01-01

    The sepsis caused by Vibrio vulnificus is characterized by an average incubation period of 26 h and a high mortality rate exceeding 50%. The fast growth and dissemination of V. vulnificus in vivo lead to poor clinical outcomes in patients. Therefore, elucidation of the proliferation mechanisms of this organism in vivo may lead to the development of an effective therapeutic strategy. In this study, we focused on the low oxygen concentration in the intestinal milieu because of its drastic difference from that in air. Fumarate and nitrate reduction regulatory protein (FNR) is known to be a global transcriptional regulator for adaptation to anaerobic conditions in various bacteria. We generated a strain of V. vulnificus in which the fnr gene was replaced with an erythromycin resistance gene (fnr::erm mutant). When the fnr::erm mutant was tested in a growth competition assay against the wild-type (WT) in vivo, the competitive index of fnr::erm mutant to WT in the intestinal loop and liver was 0.378 ± 0.192 (mean ± SD) and 0.243 ± 0.123, respectively. These data suggested that FNR is important for the proliferation of V. vulnificus in the intestine to achieve a critical mass to be able to invade the systemic circulation.

  14. Crystal structures of catalytic and regulatory subunits of rat protein kinase CK2

    Institute of Scientific and Technical Information of China (English)

    ZHOU WeiHong; SHEN YueQuan; QIN XiaoHong; YAN XiaoJie; XIE XingQiao; LI Liang; FANG ShaSha; LONG JiaFu; ADELMAN John; TANG Wei-Jen

    2009-01-01

    Protein kinase CK2 consists of two catalytic subunits (CK2α) and two regulatory subunits (CK2β). Here,we report the crystal structures of rat CK2α mutant (rCK2α-△C, 1-335) and CK2β(rCK2β). The overall topology of rCK2α-△C and rCK2βare very similar to the human enzyme, although large structural dif-ferences could be observed in the N-terminal domain of rCK2α-△C. Our reported structure of rCK2α-△C is in the close conformation state while the counterpart hCK2α is in the open conformation state, indi-cating the conformation of CK2α molecule has high plasticity. The structure of rCK2β represents the conformation of free CK2β. Upon CK2α binding, the C-terminal region undergoes a drastic conforma-tional change. The major region of interaction within the interface of CK2αCK2β may serve as a bridge to transmit the conformational change and thus regulate the activity of CK2α.

  15. Human Sterol Regulatory Element-Binding Protein 1a Contributes Significantly to Hepatic Lipogenic Gene Expression

    Directory of Open Access Journals (Sweden)

    Andreas Bitter

    2015-01-01

    Full Text Available Background/Aims: Sterol regulatory element-binding protein (SREBP 1, the master regulator of lipogenesis, was shown to be associated with non-alcoholic fatty liver disease, which is attributed to its major isoform SREBP1c. Based on studies in mice, the minor isoform SREBP1a is regarded as negligible for hepatic lipogenesis. This study aims to elucidate the expression and functional role of SREBP1a in human liver. Methods: mRNA expression of both isoforms was quantified in cohorts of human livers and primary human hepatocytes. Hepatocytes were treated with PF-429242 to inhibit the proteolytic activation of SREBP precursor protein. SREBP1a-specifc and pan-SREBP1 knock-down were performed by transfection of respective siRNAs. Lipogenic SREBP-target gene expression was analyzed by real-time RT-PCR. Results: In human liver, SREBP1a accounts for up to half of the total SREBP1 pool. Treatment with PF-429242 indicated SREBP-dependent auto-regulation of SREBP1a, which however was much weaker than of SREBP1c. SREBP1a-specifc knock-down also reduced significantly the expression of SREBP1c and of SREBP-target genes. Regarding most SREBP-target genes, simultaneous knock-down of both isoforms resulted in effects of only similar extent as SREBP1a-specific knock-down. Conclusion: We here showed that SREBP1a is significantly contributing to the human hepatic SREBP1 pool and has a share in human hepatic lipogenic gene expression.

  16. Heat Shock Protein 90 Modulates Lipid Homeostasis by Regulating the Stability and Function of Sterol Regulatory Element-binding Protein (SREBP) and SREBP Cleavage-activating Protein.

    Science.gov (United States)

    Kuan, Yen-Chou; Hashidume, Tsutomu; Shibata, Takahiro; Uchida, Koji; Shimizu, Makoto; Inoue, Jun; Sato, Ryuichiro

    2017-02-17

    Sterol regulatory element-binding proteins (SREBPs) are the key transcription factors that modulate lipid biosynthesis. SREBPs are synthesized as endoplasmic reticulum-bound precursors that require proteolytic activation in the Golgi apparatus. The stability and maturation of precursor SREBPs depend on their binding to SREBP cleavage-activating protein (SCAP), which escorts the SCAP-SREBP complex to the Golgi apparatus. In this study, we identified heat shock protein (HSP) 90 as a novel SREBP regulator that binds to and stabilizes SCAP-SREBP. In HepG2 cells, HSP90 inhibition led to proteasome-dependent degradation of SCAP-SREBP, which resulted in the down-regulation of SREBP target genes and the reduction in intracellular triglyceride and cholesterol levels. We also demonstrated in vivo that HSP90 inhibition decreased SCAP-SREBP protein, down-regulated SREBP target genes, and reduced lipids levels in mouse livers. We propose that HSP90 plays an indispensable role in SREBP regulation by stabilizing the SCAP-SREBP complex, facilitating the activation of SREBP to maintain lipids homeostasis.

  17. Arginine Catabolism and the Arginine Succinyltransferase Pathway in Escherichia coli

    OpenAIRE

    Schneider, Barbara L.; Kiupakis, Alexandros K.; Reitzer, Lawrence J.

    1998-01-01

    Arginine catabolism produces ammonia without transferring nitrogen to another compound, yet the only known pathway of arginine catabolism in Escherichia coli (through arginine decarboxylase) does not produce ammonia. Our aims were to find the ammonia-producing pathway of arginine catabolism in E. coli and to examine its function. We showed that the only previously described pathway of arginine catabolism, which does not produce ammonia, accounted for only 3% of the arginine consumed. A search...

  18. Substrate uptake and subcellular compartmentation of anoxic cholesterol catabolism in Sterolibacterium denitrificans.

    Science.gov (United States)

    Lin, Ching-Wen; Wang, Po-Hsiang; Ismail, Wael; Tsai, Yu-Wen; El Nayal, Ashraf; Yang, Chia-Ying; Yang, Fu-Chun; Wang, Chia-Hsiang; Chiang, Yin-Ru

    2015-01-09

    Cholesterol catabolism by actinobacteria has been extensively studied. In contrast, the uptake and catabolism of cholesterol by Gram-negative species are poorly understood. Here, we investigated microbial cholesterol catabolism at the subcellular level. (13)C metabolomic analysis revealed that anaerobically grown Sterolibacterium denitrificans, a β-proteobacterium, adopts an oxygenase-independent pathway to degrade cholesterol. S. denitrificans cells did not produce biosurfactants upon growth on cholesterol and exhibited high cell surface hydrophobicity. Moreover, S. denitrificans did not produce extracellular catabolic enzymes to transform cholesterol. Accordingly, S. denitrificans accessed cholesterol by direction adhesion. Cholesterol is imported through the outer membrane via a putative FadL-like transport system, which is induced by neutral sterols. The outer membrane steroid transporter is able to selectively import various C27 sterols into the periplasm. S. denitrificans spheroplasts exhibited a significantly higher efficiency in cholest-4-en-3-one-26-oic acid uptake than in cholesterol uptake. We separated S. denitrificans proteins into four fractions, namely the outer membrane, periplasm, inner membrane, and cytoplasm, and we observed the individual catabolic reactions within them. Our data indicated that, in the periplasm, various periplasmic and peripheral membrane enzymes transform cholesterol into cholest-4-en-3-one-26-oic acid. The C27 acidic steroid is then transported into the cytoplasm, in which side-chain degradation and the subsequent sterane cleavage occur. This study sheds light into microbial cholesterol metabolism under anoxic conditions.

  19. Source of dietary protein influences kinetics of plasma gut regulatory peptide concentration in response to feeding in preruminant calves.

    Science.gov (United States)

    le Huërou-Luron, I; Gestin, M; Le Dréan, G; Romé, V; Bernard, C; Chayvialle, J A; Guilloteau, P

    1998-03-01

    The kinetics of the peripheral plasma concentrations of eight gut regulatory peptides were examined in response to feeding in preruminant calves. Two experiments were carried out in animals fed milk substitutes either based on milk protein (control diet) or in which casein had been replaced by hydrolyzed fish (fish diet in experiment 1) or whey (whey diet in experiment 2) protein concentrate. In contrast to the control diet, the latter two did not coagulate within the abomasum. No variation was observed in plasma concentrations of gut regulatory peptides during 1-1.4 hr before the morning meal regardless of the nature of the dietary protein. With the control diet, the meal was followed by an increase in cholecystokinin, gastrin and gastric inhibitory polypeptide and a fall in secretin, vasoactive intestinal polypeptide and motilin, whereas no significant change was observed for somatostatin and pancreatic polypeptide. The replacement of casein by protein substitutes did not greatly modify the pattern of plasma responses to feeding, but the prefeeding and postfeeding levels were highly affected. We conclude that the most important characteristic influencing plasma gut peptide concentrations is the ability of dietary protein to clot in the abomasum, consequently determining the pattern of gastric emptying, and that variations appear depending on the origin of protein substitutes in relation to the duodenal content and mainly to the digesta pH.

  20. Redox Modulation of Cellular Signaling and Metabolism Through Reversible Oxidation of Methionine Sensors in Calcium Regulatory Proteins

    Energy Technology Data Exchange (ETDEWEB)

    Bigelow, Diana J.; Squier, Thomas C.

    2005-01-17

    Adaptive responses associated with environmental stressors are critical to cell survival. These involve the modulation of central signaling protein functions through site-specific and enzymatically reversible oxidative modifications of methionines to coordinate cellular metabolism, energy utilization, and calcium signaling. Under conditions when cellular redox and antioxidant defenses are overwhelmed, the selective oxidation of critical methionines within selected protein sensors functions to down-regulate energy metabolism and the further generation of reactive oxygen species (ROS). Mechanistically, these functional changes within protein sensors take advantage of the helix-breaking character of methionine sulfoxide. Thus, depending on either the ecological niche of the organism or the cellular milieu of different organ systems, cellular metabolism can be fine-tuned to maintain optimal function in the face of variable amounts of collateral oxidative damage. The sensitivity of several calcium regulatory proteins to oxidative modification provides cellular sensors that link oxidative stress to cellular response and recovery. Calmodulin (CaM) is one such critical calcium regulatory protein, which is functionally sensitive to methionine oxidation. Helix destabilization resulting from the oxidation of either Met{sup 144} or Met{sup 145} results in the nonproductive association between CaM and target proteins. The ability of oxidized CaM to stabilize its target proteins in an inhibited state with an affinity similar to that of native (unoxidized) CaM permits this central regulatory protein to function as a cellular rheostat that down-regulates energy metabolism in response to oxidative stress. Likewise, oxidation of a methionine within a critical switch region of the regulatory protein phospholamban is expected to destabilize the phosphorylationdependent helix formation necessary for the release of enzyme inhibition, resulting in a down-regulation of the Ca-ATPase in

  1. Influence of oxygen on DNA binding, positive control, and stability of the Bradyrhizobium japonicum NifA regulatory protein.

    OpenAIRE

    1991-01-01

    Central to the genetic regulatory circuit that controls Bradyrhizobium japonicum nif and fix gene expression is the NifA protein. NifA activates transcription of several nif and fix genes and autoregulates its expression during symbiosis in soybean root nodules or in free-living microaerobic conditions. High O2 tensions result in the lack of nif expression, possibly by inactivation of NifA through oxidation of an essential metal cofactor. Several B. japonicum nif and fix promoters have upstre...

  2. The complement regulatory protein CD59: insights into attenuation of choroidal neovascularization.

    Science.gov (United States)

    Schnabolk, Gloriane; Tomlinson, Stephen; Rohrer, Bärbel

    2014-01-01

    Complement activation is associated with age-related macular degeneration (AMD), with the retinal pigment epithelium (RPE) being one of the main target tissues. In AMD, disease severity is correlated with the formation of the membrane attack complex (MAC), the terminal step in the complement cascade, as well as diminished RPE expression of CD59, a membrane-bound regulatory protein of MAC formation. This has prompted the search for therapeutic strategies based on MAC inhibition, and soluble forms of CD59 (sCD59) have been investigated in mouse laser-induced choroidal neovascularization, a model for "wet" AMD. Unlike membrane-bound CD59, sCD59 provides relatively poor cell protection from complement, and different strategies to increase sCD59 activity at the cell membrane level have been investigated. These include increasing the circulatory half-life of sCD59 by the addition of an Fc moiety; increasing the half-life of sCD59 in target tissues by modifying CD59 with a (non-specific) membrane-targeting domain; and by locally overexpressing sCD59 via adenoviral vectors. Finally, a different strategy currently under investigation employs complement receptor (CR)2-mediated targeting of CD59 exclusively to membranes under complement attack. CR2 recognizes long-lasting membrane-bound breakdown activation fragments of complement C3. CR2-CD59 may have greater therapeutic potential than other complement inhibitory approaches, since it can be administered either systemically or locally, it will bind specifically to membranes containing activated complement activation fragments, and dosing can be regulated. Hence, this strategy might offer opportunities for site-specific inhibition of complement in diseases with restricted sites of inflammation such as AMD.

  3. Control of hydroxyproline catabolism in Sinorhizobium meliloti.

    Science.gov (United States)

    White, Catharine E; Gavina, Jennilee M A; Morton, Richard; Britz-McKibbin, Philip; Finan, Turlough M

    2012-09-01

    Hydroxyproline (Hyp) in decaying organic matter is a rich source of carbon and nitrogen for microorganisms. A bacterial pathway for Hyp catabolism is known; however, genes and function relationships are not established. In the pathway, trans-4-hydroxy-L-proline (4-L-Hyp) is epimerized to cis-4-hydroxy-D-proline (4-D-Hyp), and then, in three enzymatic reactions, the D-isomer is converted via Δ-pyrroline-4-hydroxy-2-carboxylate (HPC) and α-ketoglutarate semialdehyde (KGSA) to α-ketoglutarate (KG). Here a transcriptional analysis of cells growing on 4-L-Hyp, and the regulation and functions of genes from a Hyp catabolism locus of the legume endosymbiont Sinorhizobium meliloti are reported. Fourteen hydroxyproline catabolism genes (hyp), in five transcripts hypR, hypD, hypH, hypST and hypMNPQO(RE)XYZ, were negatively regulated by hypR. hypRE was shown to encode 4-hydroxyproline 2-epimerase and a hypRE mutant grew with 4-D-Hyp but not 4-L-Hyp. hypO, hypD and hypH are predicted to encode 4-D-Hyp oxidase, HPC deaminase and α-KGSA dehydrogenase respectively. The functions for hypS, hypT, hypX, hypY and hypZ remain to be determined. The data suggest 4-Hyp is converted to the tricarboxylic acid cycle intermediate α-ketoglutarate via the pathway established biochemically for Pseudomonas. This report describes the first molecular characterization of a Hyp catabolism locus.

  4. Involvement of the iron regulatory protein from Eisenia andrei earthworms in the regulation of cellular iron homeostasis.

    Directory of Open Access Journals (Sweden)

    Petra Procházková

    Full Text Available Iron homeostasis in cells is regulated by iron regulatory proteins (IRPs that exist in different organisms. IRPs are cytosolic proteins that bind to iron-responsive elements (IREs of the 5'- or 3'-untranslated regions (UTR of mRNAs that encode many proteins involved in iron metabolism. In this study, we have cloned and described a new regulatory protein belonging to the family of IRPs from the earthworm Eisenia andrei (EaIRP. The earthworm IRE site in 5'-UTR of ferritin mRNA most likely folds into a secondary structure that differs from the conventional IRE structures of ferritin due to the absence of a typically unpaired cytosine that participates in protein binding. Prepared recombinant EaIRP and proteins from mammalian liver extracts are able to bind both mammalian and Eisenia IRE structures of ferritin mRNA, although the affinity of the rEaIRP/Eisenia IRE structure is rather low. This result suggests the possible contribution of a conventional IRE structure. When IRP is supplemented with a Fe-S cluster, it can function as a cytosolic aconitase. Cellular cytosolic and mitochondrial fractions, as well as recombinant EaIRP, exhibit aconitase activity that can be abolished by the action of oxygen radicals. The highest expression of EaIRP was detected in parts of the digestive tract. We can assume that earthworms may possess an IRE/IRP regulatory network as a potential mechanism for maintaining cellular iron homeostasis, although the aconitase function of EaIRP is most likely more relevant.

  5. Cysteine catabolism: a novel metabolic pathway contributing to glioblastoma growth.

    Science.gov (United States)

    Prabhu, Antony; Sarcar, Bhaswati; Kahali, Soumen; Yuan, Zhigang; Johnson, Joseph J; Adam, Klaus-Peter; Kensicki, Elizabeth; Chinnaiyan, Prakash

    2014-02-01

    The relevance of cysteine metabolism in cancer has gained considerable interest in recent years, largely focusing on its role in generating the antioxidant glutathione. Through metabolomic profiling using a combination of high-throughput liquid and gas chromatography-based mass spectrometry on a total of 69 patient-derived glioma specimens, this report documents the discovery of a parallel pathway involving cysteine catabolism that results in the accumulation of cysteine sulfinic acid (CSA) in glioblastoma. These studies identified CSA to rank as one of the top metabolites differentiating glioblastoma from low-grade glioma. There was strong intratumoral concordance of CSA levels with expression of its biosynthetic enzyme cysteine dioxygenase 1 (CDO1). Studies designed to determine the biologic consequence of this metabolic pathway identified its capacity to inhibit oxidative phosphorylation in glioblastoma cells, which was determined by decreased cellular respiration, decreased ATP production, and increased mitochondrial membrane potential following pathway activation. CSA-induced attenuation of oxidative phosphorylation was attributed to inhibition of the regulatory enzyme pyruvate dehydrogenase. Studies performed in vivo abrogating the CDO1/CSA axis using a lentiviral-mediated short hairpin RNA approach resulted in significant tumor growth inhibition in a glioblastoma mouse model, supporting the potential for this metabolic pathway to serve as a therapeutic target. Collectively, we identified a novel, targetable metabolic pathway involving cysteine catabolism contributing to the growth of aggressive high-grade gliomas. These findings serve as a framework for future investigations designed to more comprehensively determine the clinical application of this metabolic pathway and its contributory role in tumorigenesis.

  6. Functional characterization and expression analysis of rice δ(1)-pyrroline-5-carboxylate dehydrogenase provide new insight into the regulation of proline and arginine catabolism.

    Science.gov (United States)

    Forlani, Giuseppe; Bertazzini, Michele; Zarattini, Marco; Funck, Dietmar

    2015-01-01

    While intracellular proline accumulation in response to various stress conditions has been investigated in great detail, the biochemistry and physiological relevance of proline degradation in plants is much less understood. Moreover, the second and last step in proline catabolism, the oxidation of δ(1)-pyrroline-5-carboxylic acid (P5C) to glutamate, is shared with arginine catabolism. Little information is available to date concerning the regulatory mechanisms coordinating these two pathways. Expression of the gene coding for P5C dehydrogenase was analyzed in rice by real-time PCR either following the exogenous supply of amino acids of the glutamate family, or under hyperosmotic stress conditions. The rice enzyme was heterologously expressed in E. coli, and the affinity-purified protein was thoroughly characterized with respect to structural and functional properties. A tetrameric oligomerization state was observed in size exclusion chromatography, which suggests a structure of the plant enzyme different from that shown for the bacterial P5C dehydrogenases structurally characterized to date. Kinetic analysis accounted for a preferential use of NAD(+) as the electron acceptor. Cations were found to modulate enzyme activity, whereas anion effects were negligible. Several metal ions were inhibitory in the micromolar range. Interestingly, arginine also inhibited the enzyme at higher concentrations, with a mechanism of uncompetitive type with respect to P5C. This implies that millimolar levels of arginine would increase the affinity of P5C dehydrogenase toward its specific substrate. Results are discussed in view of the involvement of the enzyme in either proline or arginine catabolism.

  7. CTL Responses to Regulatory Proteins Tat and Rev in HIV-1 B'/C Virus-Infected Individuals

    Institute of Scientific and Technical Information of China (English)

    MING-MING JIA; KUN-XUE HONG; JIAN-PING CHEN; HONG-WEI LIU; SHA LIU; XIAO-QING ZHANG; HONG-JING ZHAO; YI-MING SHAO

    2008-01-01

    To characterize HIV-1 specific CTL responses to regulatory proteins Tat and Rev in HIV-B'/C vires-infected ART-naive individuals. Methods HIV-1-specific CTL responses were analyzed by IFN-γ ELISPOT assay using overlapping peptides spanning the consensus sequences of HIV-1 clade C Tat and Rev proteins. Statistical analysis and graphical presentation were performed using SIGMAPLOT 10.0 and SIGMASTAT 3.5. For samples with a positive response, the magnitude of CTL responses was compared between HIV-1 C proteins by Wilcoxon rank sum test, and the significance threshold was P<0.05. Results Tat and Rev were frequently recognized, with 23% and 52% of the tested individuals having detectable responses to these proteins, respectively. Several immunodominant regions were detected in Rev. No significant correlation was observed between the magnitude and breadth of CTL responses to regulatory proteins and the control of virus replication in this study. Conclusion Tat and Rev can serve as targets for HIV-1-specific CTL, and several immunodominant regions are detectable in Rev. Further characterization of epitopes and their role in virus control may shed light on pathogenesis of HIV-1 natural infection and also be useful for the design and testing of candidate vaccines.

  8. Partitioning of genetic variation between regulatory and coding gene segments: the predominance of software variation in genes encoding introvert proteins.

    Science.gov (United States)

    Mitchison, A

    1997-01-01

    In considering genetic variation in eukaryotes, a fundamental distinction can be made between variation in regulatory (software) and coding (hardware) gene segments. For quantitative traits the bulk of variation, particularly that near the population mean, appears to reside in regulatory segments. The main exceptions to this rule concern proteins which handle extrinsic substances, here termed extrovert proteins. The immune system includes an unusually large proportion of this exceptional category, but even so its chief source of variation may well be polymorphism in regulatory gene segments. The main evidence for this view emerges from genome scanning for quantitative trait loci (QTL), which in the case of the immune system points to a major contribution of pro-inflammatory cytokine genes. Further support comes from sequencing of major histocompatibility complex (Mhc) class II promoters, where a high level of polymorphism has been detected. These Mhc promoters appear to act, in part at least, by gating the back-signal from T cells into antigen-presenting cells. Both these forms of polymorphism are likely to be sustained by the need for flexibility in the immune response. Future work on promoter polymorphism is likely to benefit from the input from genome informatics.

  9. Cloning, expression, purification and crystallization of a transcriptional regulatory protein (Rv3291c) from Mycobacterium tuberculosis H37Rv.

    Science.gov (United States)

    Shrivastava, Tripti; Kumar, Sandeep; Ramachandran, Ravishankar

    2004-10-01

    Rv3291c, the translational product of the Mycobacterium tuberculosis Rv3291c gene, is an 18 kDa protein. It is a putative transcriptional regulatory protein belonging to the leucine-responsive regulatory protein/asparagine synthase C (Lrp/AsnC) family, which are proteins that have been identified in archaea and bacteria. Rv3291c probably plays a significant role during the persistent/latent phase of M. tuberculosis, as supported by its up-regulation several-fold during this stage. Orthorhombic crystals of recombinant Rv3291c have been grown from trisodium citrate dihydrate-buffered solutions containing monoammonium dihydrogen phosphate. Diffraction data extending to 2.7 A have been collected from a single crystal with unit-cell parameters a = 99.6, b = 100.7, c = 100.6 A. Assuming an octamer in the asymmetric unit results in a Matthews coefficient (VM) of 1.75 A3 Da(-1), corresponding to a solvent content of about 30%.

  10. 14-3-3 checkpoint regulatory proteins interact specifically with DNA repair protein human exonuclease 1 (hEXO1) via a semi-conserved motif

    DEFF Research Database (Denmark)

    Andersen, Sofie Dabros; Keijzers, Guido; Rampakakis, Emmanouil

    2012-01-01

    Human exonuclease 1 (hEXO1) acts directly in diverse DNA processing events, including replication, mismatch repair (MMR), and double strand break repair (DSBR), and it was also recently described to function as damage sensor and apoptosis inducer following DNA damage. In contrast, 14-3-3 proteins...... experiments reveal weak affinity of the more selective isoform 14-3-3s but both 14-3-3 isoforms ¿ and s significantly stimulate hEXO1 activity, indicating that these regulatory proteins exert a common regulation mode on hEXO1. Results demonstrate that binding involves the phosphorable amino acid S746 in hEXO1...... are specifically induced by replication inhibition leading to protein ubiquitination and degradation. We demonstrate direct and robust interaction between hEXO1 and six of the seven 14-3-3 isoforms in vitro, suggestive of a novel protein interaction network between DNA repair and cell cycle control. Binding...

  11. Inactivation of a heterocyst-specific invertase indicates a principal role of sucrose catabolism in heterocysts of Anabaena sp.

    Science.gov (United States)

    López-Igual, Rocío; Flores, Enrique; Herrero, Antonia

    2010-10-01

    Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that carries out N(2) fixation in specialized cells called heterocysts, which exchange nutrients and regulators with the filament's vegetative cells that perform the photosynthetic fixation of CO(2). The Anabaena genome carries two genes coding for alkaline/neutral invertases, invA and invB. As shown by Northern analysis, both genes were expressed monocistronically and induced under nitrogen deprivation, although induction was stronger for invB than for invA. Whereas expression of an InvA-N-GFP fusion (green fluorescent protein [GFP] fused to the N terminus of the InvA protein [InvA-N]) was homogeneous along the cyanobacterial filament, consistent with the lack of dependence on HetR, expression of an InvB-N-GFP fusion upon combined nitrogen deprivation took place mainly in differentiating and mature heterocysts. In an hetR genetic background, the InvB-N-GFP fusion was strongly expressed all along the filament. An insertional mutant of invA could grow diazotrophically but was impaired in nifHDK induction and exhibited an increased frequency of heterocysts, suggesting a regulatory role of the invertase-mediated carbon flux in vegetative cells. In contrast, an invB mutant was strongly impaired in diazotrophic growth, showing a crucial role of sucrose catabolism mediated by the InvB invertase in the heterocysts.

  12. Catabolism of volatile organic compounds influences plant survival.

    Science.gov (United States)

    Oikawa, Patricia Y; Lerdau, Manuel T

    2013-12-01

    Plants emit a diverse array of phytogenic volatile organic compounds (VOCs). The production and emission of VOCs has been an important area of research for decades. However, recent research has revealed the importance of VOC catabolism by plants and VOC degradation in the atmosphere for plant growth and survival. Specifically, VOC catabolism and degradation have implications for plant C balance, tolerance to environmental stress, plant signaling, and plant-atmosphere interactions. Here we review recent advances in our understanding of VOC catabolism and degradation, propose experiments for investigating VOC catabolism, and suggest ways to incorporate catabolism into VOC emission models. Improving our knowledge of VOC catabolism and degradation is crucial for understanding plant metabolism and predicting plant survival in polluted environments.

  13. Catabolism of hyaluronan: involvement of transition metals

    OpenAIRE

    Šoltés, Ladislav; Kogan, Grigorij

    2009-01-01

    One of the very complex structures in the vertebrates is the joint. The main component of the joint is the synovial fluid with its high-molar-mass glycosaminoglycan hyaluronan, which turnover is approximately twelve hours. Since the synovial fluid does not contain any hyaluronidases, the fast hyaluronan catabolism is caused primarily by reductive-oxidative processes. Eight transition metals – V23, Mn25, Fe26, Co27, Ni28, Cu29, Zn30, and Mo42 – naturally occurring in living organism are essent...

  14. EWS and FUS bind a subset of transcribed genes encoding proteins enriched in RNA regulatory functions

    DEFF Research Database (Denmark)

    Luo, Yonglun; Friis, Jenny Blechingberg; Fernandes, Ana Miguel;

    2015-01-01

    and involved in the human neurological diseases amyotrophic lateral sclerosis and fronto-temporal lobar degeneration. Results To determine the gene regulatory functions of FUS and EWS at the level of chromatin, we have performed chromatin immunoprecipitation followed by next generation sequencing (Ch...

  15. 烫伤早期TNFα与IL-1增强骨骼肌蛋白质分解代谢作用机制的研究%Mechanism of TNFα and IL-1 enhancing protein catabolism in skeletal muscles of mice in early stage after severe burn

    Institute of Scientific and Technical Information of China (English)

    聂梅; 董燕麟

    2001-01-01

    Objective To observe the effects and mechanism of TNFα and IL-1 on protein catabolism of skeletal muscles of mice in the early stage of severe burn. Methods A BALB/c mice model was established with full thickness scalded of 18%~20% TBSA including the back and one hind limb. The catabolic rate of protein of soleus muscle was reflected with the net tyrosine releasing rate. The changes of the tyrosine releasing rates of the injured and uninjured limbs, the levels of TNFα and IL-1 of the plasma and soleus muscle, and the activities of lysosomal proteolytic enzymes were observed in 72 h after scald injury of the mice. Results After injury, the levels of TNFα and IL-1 of plasma, injured and uninjured limbs were all increased, and reached the summit at the 48th h, but those of the injured limb were much higher than those of the uninjured one, then gradually the levels were decreased in 72 h. The protein catabolic rate of uninjured limb was higher than the normal at h 48, but it came to normal level at h 72. The rate of the injured limb was higher than that of normal and uninjured limbs significantly 72 h after the scalding. hrTNFα and hrIL-1 enhanced the protein catabolic rate and the activities of lysosomal protrolytic enzymes in the soleus muscle of normal mice in vivo and in vitro respectively. Conclusion In the early stage of scald injury, TNFα and IL-1 could enhance the lysosomal protease activity, increase the protein catabolic rate in skeletal muscle and promote the negative nitrogen balance directly. These effects may not depend on the actions of emergent hormones.%目的 观察严重烫伤小鼠早期TNFα与IL-1对骨骼肌蛋白质分解代谢的影响及其机制。方法 建立包括背部及一侧后肢18%~20% Ⅲ度体表烫伤小鼠模型。以比目鱼肌体外温育酪氨酸净释放量反映骨骼肌蛋白质分解速率,观察72 h内伤肢、未伤肢骨骼肌蛋白质分解速率,以及血浆、伤肢、未伤肢TNFα与IL-1

  16. Stress-induced Start Codon Fidelity Regulates Arsenite-inducible Regulatory Particle-associated Protein (AIRAP) Translation*

    Science.gov (United States)

    Zach, Lolita; Braunstein, Ilana; Stanhill, Ariel

    2014-01-01

    Initial steps in protein synthesis are highly regulated processes as they define the reading frame of the translation machinery. Eukaryotic translation initiation is a process facilitated by numerous factors (eIFs), aimed to form a “scanning” mechanism toward the initiation codon. Translation initiation of the main open reading frame (ORF) in an mRNA transcript has been reported to be regulated by upstream open reading frames (uORFs) in a manner of re-initiation. This mode of regulation is governed by the phosphorylation status of eIF2α and controlled by cellular stresses. Another mode of translational initiation regulation is leaky scanning, and this regulatory process has not been extensively studied. We have identified arsenite-inducible regulatory particle-associated protein (AIRAP) transcript to be translationally induced during arsenite stress conditions. AIRAP transcript contains a single uORF in a poor-kozak context. AIRAP translation induction is governed by means of leaky scanning and not re-initiation. This induction of AIRAP is solely dependent on eIF1 and the uORF kozak context. We show that eIF1 is phosphorylated under specific conditions that induce protein misfolding and have biochemically characterized this site of phosphorylation. Our data indicate that leaky scanning like re-initiation is responsive to stress conditions and that leaky scanning can induce ORF translation by bypassing poor kozak context of a single uORF transcript. PMID:24898249

  17. Drug-drug interactions related to altered absorption and plasma protein binding: theoretical and regulatory considerations, and an industry perspective.

    Science.gov (United States)

    Hochman, Jerome; Tang, Cuyue; Prueksaritanont, Thomayant

    2015-03-01

    Drug-drug interactions (DDIs) related to altered drug absorption and plasma protein binding have received much less attention from regulatory agencies relative to DDIs mediated via drug metabolizing enzymes and transporters. In this review, a number of theoretical bases and regulatory framework are presented for these DDI aspects. Also presented is an industry perspective on how to approach these issues in support of drug development. Overall, with the exception of highly permeable and highly soluble (BCS 1) drugs, DDIs related to drug-induced changes in gastrointestinal (GI) physiology can be substantial, thus warranting more attentions. For a better understanding of absorption-associated DDI potential in a clinical setting, mechanistic studies should be conducted based on holistic integration of the pharmaceutical profiles (e.g., pH-dependent solubility) and pharmacological properties (e.g., GI physiology and therapeutic margin) of drug candidates. Although majority of DDI events related to altered plasma protein binding are not expected to be of clinical significance, exceptions exist for a subset of compounds with certain pharmacokinetic and pharmacological properties. Knowledge of the identity of binding proteins and the binding extent in various clinical setting (including disease states) can be valuable in aiding clinical DDI data interpretations, and ensuring safe and effective use of new drugs.

  18. Interaction of the regulatory and catalytic subunits of cAMP-dependent protein kinase. Electrostatic sites on the type Ialpha regulatory subunit.

    Science.gov (United States)

    Gibson, R M; Ji-Buechler, Y; Taylor, S S

    1997-06-27

    Since a basic surface on the catalytic (C) subunit of cAMP-dependent protein kinase is important for binding to the regulatory (R) subunit, acidic residues in R were sought that might contribute to R-C interaction. Using differential labeling by a water-soluble carbodiimide (Buechler, T. A., and Taylor, S. S. (1990) Biochemistry 29, 1937-1943), seven specific carboxylates in RIalpha were identified that were protected from chemical modification in the holoenzyme; each was then replaced with Ala. Of these, rRI(E15A/E106A/D107A)), rRI(E105A), rRI(D140A), rRI(E143A), and rRI(D258A) all were defective in holoenzyme formation and define negative electrostatic surfaces on RIalpha. An additional conserved carboxylate, Glu101 in RIalpha and the equivalent, Glu99 in RIIalpha were mutated to Ala. Replacement of Glu101 had no effect while rRII(E99A) was very defective. RIalpha and RIIalpha thus differ in the molecular details of how they recognize C. Unlike wild-type RI, two additional mutants, rRI(D170A) and rRI(K242A), inhibited C-subunit stoichiometrically in the presence of cAMP and show increases in both on- and off-rates. Asp170, which contributes directly to the hydrogen bonding network in cAMP-binding site A, thus contributes also to holoenzyme stability.

  19. Sterol Regulatory Element Binding Protein 1a Regulates Hepatic Fatty Acid Partitioning by Activating Acetyl Coenzyme A Carboxylase 2

    OpenAIRE

    Im, Seung-Soon; Hammond, Linda E.; Yousef, Leyla; Nugas-Selby, Cherryl; Shin, Dong-Ju; Seo, Young-Kyo; Fong, Loren G.; Young, Stephen G.; Osborne, Timothy F.

    2009-01-01

    We generated a line of mice in which sterol regulatory element binding protein 1a (SREBP-1a) was specifically inactivated by insertional mutagenesis. Homozygous mutant mice were completely viable despite expressing SREBP-1a mRNA below 5% of normal, and there were minimal effects on expression of either SREBP-1c or -2. Microarray expression studies in liver, where SREBP-1a mRNA is 1/10 the level of the highly similar SREBP-1c, demonstrated that only a few genes were affected. The only downregu...

  20. Tryptophan catabolizing enzymes – party of three

    Directory of Open Access Journals (Sweden)

    Helen J Ball

    2014-10-01

    Full Text Available Indoleamine 2,3-dioxygenase (IDO and tryptophan 2,3-dioxygenase (TDO are tryptophan-degrading enzymes that have independently evolved to catalyze the first step in tryptophan catabolism via the kynurenine pathway. The depletion of tryptophan and formation of kynurenine pathway metabolites modulates the activity of the mammalian immune, reproductive and central nervous systems. IDO and TDO enzymes can have overlapping or distinct functions depending on their expression patterns. The expression of TDO and IDO enzymes in mammals differs not only by tissue/cellular localization but also by their induction by distinct stimuli. To add to the complexity, these genes also have undergone duplications in some organisms leading to multiple isoforms of IDO or TDO. For example, many vertebrates, including all mammals, have acquired two IDO genes via gene duplication, although the IDO1-like gene has been lost in some lower vertebrate lineages. Gene duplications can allow the homologs to diverge and acquire different properties to the original gene. There is evidence for IDO enzymes having differing enzymatic characteristics, signaling properties and biological functions. This review analyses the evolutionary convergence of IDO and TDO enzymes as tryptophan-catabolizing enzymes and the divergent evolution of IDO homologs to generate an enzyme family with diverse characteristics not possessed by TDO enzymes, with an emphasis on the immune system.

  1. Insights into the evolution of sialic acid catabolism among bacteria

    Directory of Open Access Journals (Sweden)

    Almagro-Moreno Salvador

    2009-05-01

    Full Text Available Abstract Background Sialic acids comprise a family of nine-carbon amino sugars that are prevalent in mucus rich environments. Sialic acids from the human host are used by a number of pathogens as an energy source. Here we explore the evolution of the genes involved in the catabolism of sialic acid. Results The cluster of genes encoding the enzymes N-acetylneuraminate lyase (NanA, epimerase (NanE, and kinase (NanK, necessary for the catabolism of sialic acid (the Nan cluster, are confined 46 bacterial species, 42 of which colonize mammals, 33 as pathogens and 9 as gut commensals. We found a putative sialic acid transporter associated with the Nan cluster in most species. We reconstructed the phylogenetic history of the NanA, NanE, and NanK proteins from the 46 species and compared them to the species tree based on 16S rRNA. Within the NanA phylogeny, Gram-negative and Gram-positive bacteria do not form distinct clades. NanA from Yersinia and Vibrio species was most closely related to the NanA clade from eukaryotes. To examine this further, we reconstructed the phylogeny of all NanA homologues in the databases. In this analysis of 83 NanA sequences, Bacteroidetes, a human commensal group formed a distinct clade with Verrucomicrobia, and branched with the Eukaryotes and the Yersinia/Vibrio clades. We speculate that pathogens such as V. cholerae may have acquired NanA from a commensal aiding their colonization of the human gut. Both the NanE and NanK phylogenies more closely represented the species tree but numerous incidences of incongruence are noted. We confirmed the predicted function of the sialic acid catabolism cluster in members the major intestinal pathogens Salmonella enterica, Vibrio cholerae, V. vulnificus, Yersinia enterocolitica and Y. pestis. Conclusion The Nan cluster among bacteria is confined to human pathogens and commensals conferring them the ability to utilize a ubiquitous carbon source in mucus rich surfaces of the human body

  2. Regulatory pathways for ATP-binding cassette transport proteins in kidney proximal tubules

    NARCIS (Netherlands)

    Masereeuw, R.; Russel, F.G.M.

    2012-01-01

    The ATP-binding cassette transport proteins (ABC transporters) represent important determinants of drug excretion. Protective or excretory tissues where these transporters mediate substrate efflux include the kidney proximal tubule. Regulation of the transport proteins in this tissue requires elabor

  3. Identification of Novel Targets of the Human Cell Cycle Regulatory Protein Cdc34

    Science.gov (United States)

    1997-07-01

    human Cdc34 and its interacting proteins using Southern, Northern and Western blot analysis. 11 PROPRIETARY Conclusion Knowledge gained about...expression in yeast. Task 2: Month 2-3: Excision of the library (the prey) encoding candidate interacting proteins fused to the activation domain from...Cdc34 and its interacting proteins in carcinogenesis. Task 7: Month 18-28: Study of the structure of human CDC34 and its novel partner proteins in

  4. Cell Cycle and Apoptosis Regulatory Protein (CARP)-1 is Expressed inOsteoblasts and Regulated by PTH

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Sonali; Mahalingam, Chandrika D.; Das, Varsha [Department of Internal Medicine/Endocrinology, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Jamal, Shazia [Department of Oncology, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Levi, Edi [Department of Oncology, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Department of Pathology, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Rishi, Arun K. [Department of Oncology, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201 (United States); VA Medical Center, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Datta, Nabanita S., E-mail: ndatta@med.wayne.edu [Department of Internal Medicine/Endocrinology, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, MI 48201 (United States); Cardiovascular Research Institute, Wayne State University School of Medicine, Detroit, MI 48201 (United States)

    2013-07-12

    Highlights: •CARP-1 is identified for the first time in bone cells. •PTH downregulates CARP-1 expression in differentiated osteoblasts. •PTH displaces CARP-1 from nucleus to the cytoplasm in differentiated osteoblasts. •Downregulation of CARP-1 by PTH involves PKA, PKC and P-p38 MAPK pathways. -- Abstract: Bone mass is dependent on osteoblast proliferation, differentiation and life-span of osteoblasts. Parathyroid hormone (PTH) controls osteoblast cell cycle regulatory proteins and suppresses mature osteoblasts apoptosis. Intermittent administration of PTH increases bone mass but the mechanism of action are complex and incompletely understood. Cell Cycle and Apoptosis Regulatory Protein (CARP)-1 (aka CCAR1) is a novel transducer of signaling by diverse agents including cell growth and differentiation factors. To gain further insight into the molecular mechanism, we investigated involvement of CARP-1 in PTH signaling in osteoblasts. Immunostaining studies revealed presence of CARP-1 in osteoblasts and osteocytes, while a minimal to absent levels were noted in the chondrocytes of femora from 10 to 12-week old mice. Treatment of 7-day differentiated MC3T3-E1 clone-4 (MC-4) mouse osteoblastic cells and primary calvarial osteoblasts with PTH for 30 min to 5 h followed by Western blot analysis showed 2- to 3-fold down-regulation of CARP-1 protein expression in a dose- and time-dependent manner compared to the respective vehicle treated control cells. H-89, a Protein Kinase A (PKA) inhibitor, suppressed PTH action on CARP-1 protein expression indicating PKA-dependent mechanism. PMA, a Protein Kinase C (PKC) agonist, mimicked PTH action, and the PKC inhibitor, GF109203X, partially blocked PTH-dependent downregulation of CARP-1, implying involvement of PKC. U0126, a Mitogen-Activated Protein Kinase (MAPK) Kinase (MEK) inhibitor, failed to interfere with CARP-1 suppression by PTH. In contrast, SB203580, p38 inhibitor, attenuated PTH down-regulation of CARP-1

  5. Branched-chain amino acid catabolism fuels adipocyte differentiation and lipogenesis.

    Science.gov (United States)

    Green, Courtney R; Wallace, Martina; Divakaruni, Ajit S; Phillips, Susan A; Murphy, Anne N; Ciaraldi, Theodore P; Metallo, Christian M

    2016-01-01

    Adipose tissue plays important roles in regulating carbohydrate and lipid homeostasis, but less is known about the regulation of amino acid metabolism in adipocytes. Here we applied isotope tracing to pre-adipocytes and differentiated adipocytes to quantify the contributions of different substrates to tricarboxylic acid (TCA) metabolism and lipogenesis. In contrast to proliferating cells, which use glucose and glutamine for acetyl-coenzyme A (AcCoA) generation, differentiated adipocytes showed increased branched-chain amino acid (BCAA) catabolic flux such that leucine and isoleucine from medium and/or from protein catabolism accounted for as much as 30% of lipogenic AcCoA pools. Medium cobalamin deficiency caused methylmalonic acid accumulation and odd-chain fatty acid synthesis. Vitamin B12 supplementation reduced these metabolites and altered the balance of substrates entering mitochondria. Finally, inhibition of BCAA catabolism compromised adipogenesis. These results quantitatively highlight the contribution of BCAAs to adipocyte metabolism and suggest that BCAA catabolism has a functional role in adipocyte differentiation.

  6. The activation of hepatic and muscle polyamine catabolism improves glucose homeostasis.

    Science.gov (United States)

    Koponen, Taina; Cerrada-Gimenez, Marc; Pirinen, Eija; Hohtola, Esa; Paananen, Jussi; Vuohelainen, Susanna; Tusa, Maija; Pirnes-Karhu, Sini; Heikkinen, Sami; Virkamäki, Antti; Uimari, Anne; Alhonen, Leena; Laakso, Markku

    2012-02-01

    The mitochondrial biogenesis and energy expenditure regulator, PGC-1α, has been previously reported to be induced in the white adipose tissue (WAT) and liver of mice overexpressing spermidine/spermine N (1)-acetyltransferase (SSAT). The activation of PGC-1α in these mouse lines leads to increased number of mitochondria, improved glucose homeostasis, reduced WAT mass and elevated basal metabolic rate. The constant activation of polyamine catabolism produces a futile cycle that greatly reduces the ATP pools and induces 5'-AMP-activated protein kinase (AMPK), which in turn activates PGC-1α in WAT. In this study, we have investigated the effects of activated polyamine catabolism on the glucose and energy metabolisms when targeted to specific tissues. For that we used a mouse line overexpressing SSAT under the endogenous SSAT promoter, an inducible SSAT overexpressing mouse model using the metallothionein I promoter (MT-SSAT), and a mouse model with WAT-specific SSAT overexpression (aP2-SSAT). The results demonstrated that WAT-specific SSAT overexpression was sufficient to increase the number of mitochondria, reduce WAT mass and protect the mice from high-fat diet-induced obesity. However, the improvement in the glucose homeostasis is achieved only when polyamine catabolism is enhanced at the same time in the liver and skeletal muscle. Our results suggest that the tissue-specific targeting of activated polyamine catabolism may reveal new possibilities for the development of drugs boosting mitochondrial metabolism and eventually for treatment of obesity and type 2 diabetes.

  7. Evolution of a G protein-coupled receptor response by mutations in regulatory network interactions

    DEFF Research Database (Denmark)

    Di Roberto, Raphaël B; Chang, Belinda; Trusina, Ala;

    2016-01-01

    All cellular functions depend on the concerted action of multiple proteins organized in complex networks. To understand how selection acts on protein networks, we used the yeast mating receptor Ste2, a pheromone-activated G protein-coupled receptor, as a model system. In Saccharomyces cerevisiae...

  8. Defective tryptophan catabolism underlies inflammation in mouse chronic granulomatous disease.

    Science.gov (United States)

    Romani, Luigina; Fallarino, Francesca; De Luca, Antonella; Montagnoli, Claudia; D'Angelo, Carmen; Zelante, Teresa; Vacca, Carmine; Bistoni, Francesco; Fioretti, Maria C; Grohmann, Ursula; Segal, Brahm H; Puccetti, Paolo

    2008-01-10

    Half a century ago, chronic granulomatous disease (CGD) was first described as a disease fatally affecting the ability of children to survive infections. Various milestone discoveries have since been made, from an insufficient ability of patients' leucocytes to kill microbes to the underlying genetic abnormalities. In this inherited disorder, phagocytes lack NADPH oxidase activity and do not generate reactive oxygen species, most notably superoxide anion, causing recurrent bacterial and fungal infections. Patients with CGD also suffer from chronic inflammatory conditions, most prominently granuloma formation in hollow viscera. The precise mechanisms of the increased microbial pathogenicity have been unclear, and more so the reasons for the exaggerated inflammatory response. Here we show that a superoxide-dependent step in tryptophan metabolism along the kynurenine pathway is blocked in CGD mice with lethal pulmonary aspergillosis, leading to unrestrained Vgamma1(+) gammadelta T-cell reactivity, dominant production of interleukin (IL)-17, defective regulatory T-cell activity and acute inflammatory lung injury. Although beneficial effects are induced by IL-17 neutralization or gammadelta T-cell contraction, complete cure and reversal of the hyperinflammatory phenotype are achieved by replacement therapy with a natural kynurenine distal to the blockade in the pathway. Effective therapy, which includes co-administration of recombinant interferon-gamma (IFN-gamma), restores production of downstream immunoactive metabolites and enables the emergence of regulatory Vgamma4(+) gammadelta and Foxp3(+) alphabeta T cells. Therefore, paradoxically, the lack of reactive oxygen species contributes to the hyperinflammatory phenotype associated with NADPH oxidase deficiencies, through a dysfunctional kynurenine pathway of tryptophan catabolism. Yet, this condition can be reverted by reactivating the pathway downstream of the superoxide-dependent step.

  9. Catabolism and safety of supplemental L-arginine in animals.

    Science.gov (United States)

    Wu, Zhenlong; Hou, Yongqing; Hu, Shengdi; Bazer, Fuller W; Meininger, Cynthia J; McNeal, Catherine J; Wu, Guoyao

    2016-07-01

    L-arginine (Arg) is utilized via multiple pathways to synthesize protein and low-molecular-weight bioactive substances (e.g., nitric oxide, creatine, and polyamines) with enormous physiological importance. Furthermore, Arg regulates cell signaling pathways and gene expression to improve cardiovascular function, augment insulin sensitivity, enhance lean tissue mass, and reduce obesity in humans. Despite its versatile roles, the use of Arg as a dietary supplement is limited due to the lack of data to address concerns over its safety in humans. Data from animal studies are reviewed to assess arginine catabolism and the safety of long-term Arg supplementation. The arginase pathway was responsible for catabolism of 76-85 and 81-96 % Arg in extraintestinal tissues of pigs and rats, respectively. Dietary supplementation with Arg-HCl or the Arg base [315- and 630-mg Arg/(kg BW d) for 91 d] had no adverse effects on male or female pigs. Similarly, no safety issues were observed for male or female rats receiving supplementation with 1.8- and 3.6-g Arg/(kg BW d) for at least 91 d. Intravenous administration of Arg-HCl to gestating sheep at 81 and 180 mg Arg/(kg BW d) is safe for at least 82 and 40 d, respectively. Animals fed conventional diets can well tolerate large amounts of supplemental Arg [up to 630-mg Arg/(kg BW d) in pigs or 3.6-g Arg/(kg BW d) in rats] for 91 d, which are equivalent to 573-mg Arg/(kg BW d) for humans. Collectively, these results can help guide studies to determine the safety of long-term oral administration of Arg in humans.

  10. Using BAC transgenesis in zebrafish to identify regulatory sequences of the amyloid precursor protein gene in humans

    Directory of Open Access Journals (Sweden)

    Shakes Leighcraft A

    2012-09-01

    Full Text Available Abstract Background Non-coding DNA in and around the human Amyloid Precursor Protein (APP gene that is central to Alzheimer’s disease (AD shares little sequence similarity with that of appb in zebrafish. Identifying DNA domains regulating expression of the gene in such situations becomes a challenge. Taking advantage of the zebrafish system that allows rapid functional analyses of gene regulatory sequences, we previously showed that two discontinuous DNA domains in zebrafish appb are important for expression of the gene in neurons: an enhancer in intron 1 and sequences 28–31 kb upstream of the gene. Here we identify the putative transcription factor binding sites responsible for this distal cis-acting regulation, and use that information to identify a regulatory region of the human APP gene. Results Functional analyses of intron 1 enhancer mutations in enhancer-trap BACs expressed as transgenes in zebrafish identified putative binding sites of two known transcription factor proteins, E4BP4/ NFIL3 and Forkhead, to be required for expression of appb. A cluster of three E4BP4 sites at −31 kb is also shown to be essential for neuron-specific expression, suggesting that the dependence of expression on upstream sequences is mediated by these E4BP4 sites. E4BP4/ NFIL3 and XFD1 sites in the intron enhancer and E4BP4/ NFIL3 sites at −31 kb specifically and efficiently bind the corresponding zebrafish proteins in vitro. These sites are statistically over-represented in both the zebrafish appb and the human APP genes, although their locations are different. Remarkably, a cluster of four E4BP4 sites in intron 4 of human APP exists in actively transcribing chromatin in a human neuroblastoma cell-line, SHSY5Y, expressing APP as shown using chromatin immunoprecipitation (ChIP experiments. Thus although the two genes share little sequence conservation, they appear to share the same regulatory logic and are regulated by a similar set of transcription

  11. Comparative genomic analysis of two-component regulatory proteins in Pseudomonas syringae

    DEFF Research Database (Denmark)

    Lavin, J.L.; Kiil, Kristoffer; Resano, O.

    2007-01-01

    important differences in TCS proteins among the three P. syringae pathovars. Conclusion: In this article we present a thorough analysis of the identification and distribution of TCS proteins among the sequenced genomes of P. syringae. We have identified differences in TCS proteins among the three P...... requires a complex array of TCS proteins to cope with diverse plant hosts, host responses, and environmental conditions. Results: Based on the genomic data, pattern searches with Hidden Markov Model (HMM) profiles have been used to identify putative HKs and RRs. The genomes of Psy B728a, Pto DC3000 and Pph...... 1448A were found to contain a large number of genes encoding TCS proteins, and a core of complete TCS proteins were shared between these genomes: 30 putative TCS clusters, 11 orphan HKs, 33 orphan RRs, and 16 hybrid HKs. A close analysis of the distribution of genes encoding TCS proteins revealed...

  12. Increased glutamine catabolism mediates bone anabolism in response to WNT signaling.

    Science.gov (United States)

    Karner, Courtney M; Esen, Emel; Okunade, Adewole L; Patterson, Bruce W; Long, Fanxin

    2015-02-01

    WNT signaling stimulates bone formation by increasing both the number of osteoblasts and their protein-synthesis activity. It is not clear how WNT augments the capacity of osteoblast progenitors to meet the increased energetic and synthetic needs associated with mature osteoblasts. Here, in cultured osteoblast progenitors, we determined that WNT stimulates glutamine catabolism through the tricarboxylic acid (TCA) cycle and consequently lowers intracellular glutamine levels. The WNT-induced reduction of glutamine concentration triggered a general control nonderepressible 2-mediated (GCN2-mediated) integrated stress response (ISR) that stimulated expression of genes responsible for amino acid supply, transfer RNA (tRNA) aminoacylation, and protein folding. WNT-induced glutamine catabolism and ISR were β-catenin independent, but required mammalian target of rapamycin complex 1 (mTORC1) activation. In a hyperactive WNT signaling mouse model of human osteosclerosis, inhibition of glutamine catabolism or Gcn2 deletion suppressed excessive bone formation. Together, our data indicate that glutamine is both an energy source and a protein-translation rheostat that is responsive to WNT and suggest that manipulation of the glutamine/GCN2 signaling axis may provide a valuable approach for normalizing deranged protein anabolism associated with human diseases.

  13. Sterol Regulatory Element Binding Protein (Srb1) Is Required for Hypoxic Adaptation and Virulence in the Dimorphic Fungus Histoplasma capsulatum

    Science.gov (United States)

    DuBois, Juwen C.; Smulian, A. George

    2016-01-01

    The Histoplasma capsulatum sterol regulatory element binding protein (SREBP), Srb1 is a member of the basic helix-loop-helix (bHLH), leucine zipper DNA binding protein family of transcription factors that possess a unique tyrosine (Y) residue instead of an arginine (R) residue in the bHLH region. We have determined that Srb1 message levels increase in a time dependent manner during growth under oxygen deprivation (hypoxia). To further understand the role of Srb1 during infection and hypoxia, we silenced the gene encoding Srb1 using RNA interference (RNAi); characterized the resulting phenotype, determined its response to hypoxia, and its ability to cause disease within an infected host. Silencing of Srb1 resulted in a strain of H. capsulatum that is incapable of surviving in vitro hypoxia. We found that without complete Srb1 expression, H. capsulatum is killed by murine macrophages and avirulent in mice given a lethal dose of yeasts. Additionally, silencing Srb1 inhibited the hypoxic upregulation of other known H. capsulatum hypoxia-responsive genes (HRG), and genes that encode ergosterol biosynthetic enzymes. Consistent with these regulatory functions, Srb1 silenced H. capsulatum cells were hypersensitive to the antifungal azole drug itraconazole. These data support the theory that the H. capsulatum SREBP is critical for hypoxic adaptation and is required for H. capsulatum virulence. PMID:27711233

  14. A novel processing system of sterol regulatory element-binding protein-1c regulated by polyunsaturated fatty acid.

    Science.gov (United States)

    Nakakuki, Masanori; Kawano, Hiroyuki; Notsu, Tatsuto; Imada, Kazunori; Mizuguchi, Kiyoshi; Shimano, Hitoshi

    2014-05-01

    The proteolytic cascade is the key step in transactivation of sterol regulatory element-binding proteins (SREBPs), a transcriptional factor of lipid synthesis. Proteolysis of SREBP-2 is strictly regulated by sterols, but that of SREBP-1c was not strongly sterol-regulated, but inhibited by polyunsaturated fatty acids (PUFAs). In this study, the proteolytic processing of SREBP-1 and -2 was examined by transfection studies of cDNA-encoding mutants in which all the known cleavage sites were disrupted. In cultured cells, sterol-regulated SREBP-2 processing was completely eliminated by mutation of cleavage sites. In contrast, the corresponding SREBP-1c mutants as well as wild type exhibited large amounts of cleaved products in the nuclear extracts from culture cells and murine liver in vivo. The nuclear form of the mutant SREBP-1c was induced by delipidated condition and suppressed by eicosapentaenoic acid, an n-3 PUFA, but not by sterols. This novel processing mechanism was affected by neither SREBP cleavage-activating protein (SCAP) nor insulin-induced gene (Insig)-1, unlike SREBP-2, but abolished by a serine protease inhibitor. Through analysis of deletion mutant, a site-2 protease recognition sequence (DRSR) was identified to be involved in this novel processing. These findings suggest that SREBP-1c cleavage could be subjected to a novel PUFA-regulated cleavage system in addition to the sterol-regulatory SCAP/Insig system.

  15. Enzyme IIANtr Regulates Salmonella Invasion Via 1,2-Propanediol And Propionate Catabolism

    Science.gov (United States)

    Yoo, Woongjae; Kim, Dajeong; Yoon, Hyunjin; Ryu, Sangryeol

    2017-01-01

    Many Proteobacteria possess a nitrogen-metabolic phosphotransferase system (PTSNtr) consisting of EINtr, NPr, and EIIANtr (encoded by ptsP, ptsO, and ptsN, respectively). The PTSNtr plays diverse regulatory roles, but the substrate phosphorylated by EIIANtr and its primary functions have not yet been identified. To comprehensively understand the roles of PTSNtr in Salmonella Typhimurium, we compared the whole transcriptomes of wild-type and a ΔptsN mutant. Genome-wide RNA sequencing revealed that 3.5% of the annotated genes were up- or down-regulated by three-fold or more in the absence of EIIANtr. The ΔptsN mutant significantly down-regulated the expression of genes involved in vitamin B12 synthesis, 1,2-propanediol utilization, and propionate catabolism. Moreover, the invasiveness of the ΔptsN mutant increased about 5-fold when 1,2-propanediol or propionate was added, which was attributable to the increased stability of HilD, the transcriptional regulator of Salmonella pathogenicity island-1. Interestingly, an abundance of 1,2-propanediol or propionate promoted the production of EIIANtr, suggesting the possibility of a positive feedback loop between EIIANtr and two catabolic pathways. These results demonstrate that EIIANtr is a key factor for the utilization of 1,2-propanediol and propionate as carbon and energy sources, and thereby modulates the invasiveness of Salmonella via 1,2-propanediol or propionate catabolism. PMID:28333132

  16. Inactivity amplifies the catabolic response of skeletal muscle to cortisol

    Science.gov (United States)

    Ferrando, A. A.; Stuart, C. A.; Sheffield-Moore, M.; Wolfe, R. R.

    1999-01-01

    Severe injury or trauma is accompanied by both hypercortisolemia and prolonged inactivity or bed rest (BR). Trauma and BR alone each result in a loss of muscle nitrogen, albeit through different metabolic alterations. Although BR alone can result in a 2-3% loss of lean body mass, the effects of severe trauma can be 2- to 3-fold greater. We investigated the combined effects of hypercortisolemia and prolonged inactivity on muscle protein metabolism in healthy volunteers. Six males were studied before and after 14 days of strict BR using a model based on arteriovenous sampling and muscle biopsy. Fractional synthesis and breakdown rates of skeletal muscle protein were also directly calculated. Each assessment of protein metabolism was conducted during a 12-h infusion of hydrocortisone sodium succinate (120 microg/kg x h), resulting in blood cortisol concentrations that mimic severe injury (approximately 31 microg/dL). After 14 days of strict BR, hypercortisolemia increased phenylalanine efflux from muscle by 3-fold (P catabolic effects of hypercortisolemia. Furthermore, these effects on healthy volunteers are analogous to those seen after severe injury.

  17. Functional Characterization of a Novel Pro-Apoptotic Transcriptional Regulatory Protein in Ovarian Cancer

    Science.gov (United States)

    2005-01-01

    initiated studies to elucidate PAPX interacting proteins using an antibody array as described below. Although in the initial proposal, we had proposed to...identify PAPX interacting proteins with other techniques such as yeast two hybrid and GST pulldown assays, we also tried the antibody array to achieve...the same goal and were successful in identifying PAPX interacting proteins . To address Aim #3, we utilized antibody array containing antibodies against

  18. Analysis of Two Putative Candida albicans Phosphopantothenoylcysteine Decarboxylase / Protein Phosphatase Z Regulatory Subunits Reveals an Unexpected Distribution of Functional Roles

    Science.gov (United States)

    Petrényi, Katalin; Molero, Cristina; Kónya, Zoltán; Erdődi, Ferenc; Ariño, Joaquin; Dombrádi, Viktor

    2016-01-01

    Protein phosphatase Z (Ppz) is a fungus specific enzyme that regulates cell wall integrity, cation homeostasis and oxidative stress response. Work on Saccharomyces cerevisiae has shown that the enzyme is inhibited by Hal3/Vhs3 moonlighting proteins that together with Cab3 constitute the essential phosphopantothenoylcysteine decarboxylase (PPCDC) enzyme. In Candida albicans CaPpz1 is also involved in the morphological changes and infectiveness of this opportunistic human pathogen. To reveal the CaPpz1 regulatory context we searched the C. albicans database and identified two genes that, based on the structure of their S. cerevisiae counterparts, were termed CaHal3 and CaCab3. By pull down analysis and phosphatase assays we demonstrated that both of the bacterially expressed recombinant proteins were able to bind and inhibit CaPpz1 as well as its C-terminal catalytic domain (CaPpz1-Cter) with comparable efficiency. The binding and inhibition were always more pronounced with CaPpz1-Cter, indicating a protective effect against inhibition by the N-terminal domain in the full length protein. The functions of the C. albicans proteins were tested by their overexpression in S. cerevisiae. Contrary to expectations we found that only CaCab3 and not CaHal3 rescued the phenotypic traits that are related to phosphatase inhibition by ScHal3, such as tolerance to LiCl or hygromycin B, requirement for external K+ concentrations, or growth in a MAP kinase deficient slt2 background. On the other hand, both of the Candida proteins turned out to be essential PPCDC components and behaved as their S. cerevisiae counterparts: expression of CaCab3 and CaHal3 rescued the cab3 and hal3 vhs3 S. cerevisiae mutations, respectively. Thus, both CaHal3 and CaCab3 retained the PPCDC related functions and have the potential for CaPpz1 inhibition in vitro. The fact that only CaCab3 exhibits its phosphatase regulatory potential in vivo suggests that in C. albicans CaCab3, but not CaHal3, acts as a

  19. Prolactin Regulatory Element Binding Protein Is Involved in Hepatitis C Virus Replication by Interaction with NS4B

    Science.gov (United States)

    Kong, Lingbao; Fujimoto, Akira; Nakamura, Mariko; Aoyagi, Haruyo; Matsuda, Mami; Watashi, Koichi; Suzuki, Ryosuke; Arita, Minetaro; Yamagoe, Satoshi; Dohmae, Naoshi; Suzuki, Takehiro; Sakamaki, Yuriko; Ichinose, Shizuko; Suzuki, Tetsuro; Wakita, Takaji

    2016-01-01

    ABSTRACT It has been proposed that the hepatitis C virus (HCV) NS4B protein triggers the membranous HCV replication compartment, but the underlying molecular mechanism is not fully understood. Here, we screened for NS4B-associated membrane proteins by tandem affinity purification and proteome analysis and identified 202 host proteins. Subsequent screening of replicon cells with small interfering RNA identified prolactin regulatory element binding (PREB) to be a novel HCV host cofactor. The interaction between PREB and NS4B was confirmed by immunoprecipitation, immunofluorescence, and proximity ligation assays. PREB colocalized with double-stranded RNA and the newly synthesized HCV RNA labeled with bromouridine triphosphate in HCV replicon cells. Furthermore, PREB shifted to detergent-resistant membranes (DRMs), where HCV replication complexes reside, in the presence of NS4B expression in Huh7 cells. However, a PREB mutant lacking the NS4B-binding region (PREBd3) could not colocalize with double-stranded RNA and did not shift to the DRM in the presence of NS4B. These results indicate that PREB locates at the HCV replication complex by interacting with NS4B. PREB silencing inhibited the formation of the membranous HCV replication compartment and increased the protease and nuclease sensitivity of HCV replicase proteins and RNA in DRMs, respectively. Collectively, these data indicate that PREB promotes HCV RNA replication by participating in the formation of the membranous replication compartment and by maintaining its proper structure by interacting with NS4B. Furthermore, PREB was induced by HCV infection in vitro and in vivo. Our findings provide new insights into HCV host cofactors. IMPORTANCE The hepatitis C virus (HCV) protein NS4B can induce alteration of the endoplasmic reticulum and the formation of a membranous web structure, which provides a platform for the HCV replication complex. The molecular mechanism by which NS4B induces the membranous HCV replication

  20. Summer-to-Winter Phenotypic Flexibility of Fatty Acid Transport and Catabolism in Skeletal Muscle and Heart of Small Birds.

    Science.gov (United States)

    Zhang, Yufeng; King, Marisa O; Harmon, Erin; Swanson, David L

    2015-01-01

    Prolonged shivering in birds is mainly fueled by lipids. Consequently, lipid transport and catabolism are vital for thermogenic performance and could be upregulated along with thermogenic capacity as part of the winter phenotype. We investigated summer-to-winter variation in lipid transport and catabolism by measuring mRNA expression, protein levels, and enzyme activities for several key steps of lipid transport and catabolic pathways in pectoralis muscle and heart in two small temperate-zone resident birds, American goldfinches (Spinus tristis) and black-capped chickadees (Poecile atricapillus). Cytosolic fatty acid binding protein (FABPc; a key component of intramyocyte lipid transport) mRNA and/or protein levels were generally higher in winter for pectoralis muscle and heart for both species. However, seasonal variation in plasma membrane lipid transporters, fatty acyl translocase, and plasma membrane fatty acid binding protein in pectoralis and heart differed between the two species, with winter increases for chickadees and seasonal stability or summer increases for goldfinches. Catabolic enzyme activities generally showed limited seasonal differences for both tissues and both species. These data suggest that FABPc is an important target of upregulation for the winter phenotype in pectoralis and heart of both species. Plasma membrane lipid transporters and lipid catabolic capacity were also elevated in winter for chickadees but not for goldfinches. Because the two species show differential regulation of distinct aspects of lipid transport and catabolism, these data are consistent with other recent studies documenting that different bird species or populations employ a variety of strategies to promote elevated winter thermogenic capacity.

  1. Detection of hCG Responsive Expression of the Steroidogenic Acute Regulatory Protein in Mouse Leydig Cells

    Directory of Open Access Journals (Sweden)

    Manna Pulak R.

    2004-01-01

    Full Text Available The steroidogenic acute regulatory (StAR protein, a novel mitochondrial protein, is involved in the regulation of steroid hormone biosynthesis through its mediation of the intramitochondrial transport of the steroid substrate, cholesterol, to the cytochrome P450 cholesterol side chain cleavage (P450scc enzyme. The expression of StAR protein is regulated by cAMP-dependent signaling in steroidogenic cells. During the course of our studies in mouse Leydig cells, we employ several methods for studying the regulation of StAR protein expression by human chorionic gonadotropin (hCG. A sensitive quantitative reverse transcription and polymerase chain reaction (RT-PCR was utilized for determining StAR mRNA expression. Stimulation of mLTC-1 mouse Leydig tumor cells with hCG resulted in the coordinate regulation of StAR mRNA expression and progesterone accumulation in a time-response manner. The validity and accuracy of quantitative RT-PCR results in mLTC-1 cells were verified by a competitive PCR approach and were further confirmed in primary cultures of isolated mouse Leydig cells. Immunoblotting studies demonstrated an increase in the levels of the StAR protein in a concentration dependent manner following hCG stimulation in mLTC-1 cells. Northern hybridization analysis revealed three StAR transcripts, all of which were of sufficient size to encode functional StAR protein, and which were coordinately expressed in response to hCG. Collectively, the experimental approaches utilized in the present investigation allow for the demonstration and characterization of hCG mediated regulation of StAR mRNA and StAR protein expression in mouse Leydig cells.

  2. A Program for the Study of Skeletal Muscle Catabolism Following Physical Trauma.

    Science.gov (United States)

    1987-12-06

    amino acids ( BCAA - leucine, isoleucine, and valine) are the only essential amino acids that are primarily oxidized in skeletal muscle (16). The amino...it is clear that BCAA (primarily leucine) can reduce net protein degradation in vitro, the effect of amino acid formulas supplemented with additional... BCAA on skeletal muscle breakdown in catabolic patients remains controversial. For example, Freund and Cerra have administered solutions containing up

  3. Intracellular growth is dependent on tyrosine catabolism in the dimorphic fungal pathogen Penicillium marneffei.

    Science.gov (United States)

    Boyce, Kylie J; McLauchlan, Alisha; Schreider, Lena; Andrianopoulos, Alex

    2015-03-01

    During infection, pathogens must utilise the available nutrient sources in order to grow while simultaneously evading or tolerating the host's defence systems. Amino acids are an important nutritional source for pathogenic fungi and can be assimilated from host proteins to provide both carbon and nitrogen. The hpdA gene of the dimorphic fungus Penicillium marneffei, which encodes an enzyme which catalyses the second step of tyrosine catabolism, was identified as up-regulated in pathogenic yeast cells. As well as enabling the fungus to acquire carbon and nitrogen, tyrosine is also a precursor in the formation of two types of protective melanin; DOPA melanin and pyomelanin. Chemical inhibition of HpdA in P. marneffei inhibits ex vivo yeast cell production suggesting that tyrosine is a key nutrient source during infectious growth. The genes required for tyrosine catabolism, including hpdA, are located in a gene cluster and the expression of these genes is induced in the presence of tyrosine. A gene (hmgR) encoding a Zn(II)2-Cys6 binuclear cluster transcription factor is present within the cluster and is required for tyrosine induced expression and repression in the presence of a preferred nitrogen source. AreA, the GATA-type transcription factor which regulates the global response to limiting nitrogen conditions negatively regulates expression of cluster genes in the absence of tyrosine and is required for nitrogen metabolite repression. Deletion of the tyrosine catabolic genes in the cluster affects growth on tyrosine as either a nitrogen or carbon source and affects pyomelanin, but not DOPA melanin, production. In contrast to other genes of the tyrosine catabolic cluster, deletion of hpdA results in no growth within macrophages. This suggests that the ability to catabolise tyrosine is not required for macrophage infection and that HpdA has an additional novel role to that of tyrosine catabolism and pyomelanin production during growth in host cells.

  4. Cytoplasmic dynein and its regulatory proteins in Golgi pathology in nervous system disorders

    NARCIS (Netherlands)

    Jaarsma, Dick; Hoogenraad, Casper C

    2015-01-01

    The Golgi apparatus is a dynamic organelle involved in processing and sorting of lipids and proteins. In neurons, the Golgi apparatus is important for the development of axons and dendrites and maintenance of their highly complex polarized morphology. The motor protein complex cytoplasmic dynein has

  5. Cytoplasmic dynein and its regulatory proteins in Golgi pathology in nervous system disorders

    NARCIS (Netherlands)

    D. Jaarsma (Dick); C.C. Hoogenraad (Casper)

    2015-01-01

    textabstractThe Golgi apparatus is a dynamic organelle involved in processing and sorting of lipids and proteins. In neurons, the Golgi apparatus is important for the development of axons and dendrites and maintenance of their highly complex polarized morphology. The motor protein complex cytoplasmi

  6. Structural Dynamics and Conformational Equilibria of SERCA Regulatory Proteins in Membranes by Solid-State NMR Restrained Simulations

    Science.gov (United States)

    De Simone, Alfonso; Mote, Kaustubh R.; Veglia, Gianluigi

    2014-01-01

    Solid-state NMR spectroscopy is emerging as a powerful approach to determine structure, topology, and conformational dynamics of membrane proteins at the atomic level. Conformational dynamics are often inferred and quantified from the motional averaging of the NMR parameters. However, the nature of these motions is difficult to envision based only on spectroscopic data. Here, we utilized restrained molecular dynamics simulations to probe the structural dynamics, topology and conformational transitions of regulatory membrane proteins of the calcium ATPase SERCA, namely sarcolipin and phospholamban, in explicit lipid bilayers. Specifically, we employed oriented solid-state NMR data, such as dipolar couplings and chemical shift anisotropy measured in lipid bicelles, to refine the conformational ensemble of these proteins in lipid membranes. The samplings accurately reproduced the orientations of transmembrane helices and showed a significant degree of convergence with all of the NMR parameters. Unlike the unrestrained simulations, the resulting sarcolipin structures are in agreement with distances and angles for hydrogen bonds in ideal helices. In the case of phospholamban, the restrained ensemble sampled the conformational interconversion between T (helical) and R (unfolded) states for the cytoplasmic region that could not be observed using standard structural refinements with the same experimental data set. This study underscores the importance of implementing NMR data in molecular dynamics protocols to better describe the conformational landscapes of membrane proteins embedded in realistic lipid membranes. PMID:24940774

  7. Disruption of the regulatory beta subunit of protein kinase CK2 in mice leads to a cell-autonomous defect and early embryonic lethality

    DEFF Research Database (Denmark)

    Buchou, Thierry; Vernet, Muriel; Blond, Olivier

    2003-01-01

    Protein kinase CK2 is a ubiquitous protein kinase implicated in proliferation and cell survival. Its regulatory beta subunit, CK2beta, which is encoded by a single gene in mammals, has been suspected of regulating other protein kinases. In this work, we show that knockout of the CK2beta gene in m....... Thus, our study demonstrates that in mammals, CK2beta is essential for viability at the cellular level, possibly because it acquired new functions during evolution.......Protein kinase CK2 is a ubiquitous protein kinase implicated in proliferation and cell survival. Its regulatory beta subunit, CK2beta, which is encoded by a single gene in mammals, has been suspected of regulating other protein kinases. In this work, we show that knockout of the CK2beta gene...

  8. The mitochondrial PPR protein LOVASTATIN INSENSITIVE 1 plays regulatory roles in cytosolic and plastidial isoprenoid biosynthesis through RNA editing.

    Science.gov (United States)

    Tang, Jianwei; Kobayashi, Keiko; Suzuki, Masashi; Matsumoto, Shogo; Muranaka, Toshiya

    2010-02-01

    Unlike animals, plants synthesize isoprenoids via two pathways, the cytosolic mevalonate (MVA) pathway and the plastidial 2-C-methyl-d-erythritol-4-phosphate (MEP) pathway. Little information is known about the mechanisms that regulate these complex biosynthetic networks over multiple organelles. To understand such regulatory mechanisms of the biosynthesis of isoprenoids in plants, we previously characterized the Arabidopsis mutant, lovastatin insensitive 1 (loi1), which is resistant to lovastatin and clomazone, specific inhibitors of the MVA and MEP pathways, respectively. LOI1 encodes a pentatricopeptide repeat (PPR) protein localized in mitochondria that is thought to have RNA binding ability and function in post-transcriptional regulation of mitochondrial gene expression. LOI1 belongs to the DYW subclass of PPR proteins, which is hypothesized to be correlated with RNA editing. As a result of analysis of RNA editing of mitochondrial genes in loi1, a defect in RNA editing of three genes, nad4, ccb203 and cox3, was identified in loi1. These genes are related to the respiratory chain. Wild type (WT) treated with some respiration inhibitors mimicked the loi1 phenotype. Interestingly, HMG-CoA reductase activity of WT treated with lovastatin combined with antimycin A, an inhibitor of complex III in the respiratory chain, was higher than that of WT treated with only lovastatin, despite the lack of alteration of transcript or protein levels of HMGR. These results suggest that HMGR enzyme activity is regulated through the respiratory cytochrome pathway. Although various mechanisms exist for isoprenoid biosynthesis, our studies demonstrate the novel possibility that mitochondrial respiration plays potentially regulatory roles in isoprenoid biosynthesis.

  9. The nitrogen-regulated response regulator NrrA controls cyanophycin synthesis and glycogen catabolism in the cyanobacterium Synechocystis sp. PCC 6803.

    Science.gov (United States)

    Liu, Deng; Yang, Chen

    2014-01-24

    The cellular metabolism in cyanobacteria is extensively regulated in response to changes of environmental nitrogen availability. Multiple regulators are involved in this process, including a nitrogen-regulated response regulator NrrA. However, the regulatory role of NrrA in most cyanobacteria remains to be elucidated. In this study, we combined a comparative genomic reconstruction of NrrA regulons in 15 diverse cyanobacterial species with detailed experimental characterization of NrrA-mediated regulation in Synechocystis sp. PCC 6803. The reconstructed NrrA regulons in most species included the genes involved in glycogen catabolism, central carbon metabolism, amino acid biosynthesis, and protein degradation. A predicted NrrA-binding motif consisting of two direct repeats of TG(T/A)CA separated by an 8-bp A/T-rich spacer was verified by in vitro binding assays with purified NrrA protein. The predicted target genes of NrrA in Synechocystis sp. PCC 6803 were experimentally validated by comparing the transcript levels and enzyme activities between the wild-type and nrrA-inactivated mutant strains. The effect of NrrA deficiency on intracellular contents of arginine, cyanophycin, and glycogen was studied. Severe impairments in arginine synthesis and cyanophycin accumulation were observed in the nrrA-inactivated mutant. The nrrA inactivation also resulted in a significantly decreased rate of glycogen degradation. Our results indicate that by directly up-regulating expression of the genes involved in arginine synthesis, glycogen degradation, and glycolysis, NrrA controls cyanophycin accumulation and glycogen catabolism in Synechocystis sp. PCC 6803. It is suggested that NrrA plays a role in coordinating the synthesis and degradation of nitrogen and carbon reserves in cyanobacteria.

  10. Selection on Coding and Regulatory Variation Maintains Individuality in Major Urinary Protein Scent Marks in Wild Mice.

    Directory of Open Access Journals (Sweden)

    Michael J Sheehan

    2016-03-01

    Full Text Available Recognition of individuals by scent is widespread across animal taxa. Though animals can often discriminate chemical blends based on many compounds, recent work shows that specific protein pheromones are necessary and sufficient for individual recognition via scent marks in mice. The genetic nature of individuality in scent marks (e.g. coding versus regulatory variation and the evolutionary processes that maintain diversity are poorly understood. The individual signatures in scent marks of house mice are the protein products of a group of highly similar paralogs in the major urinary protein (Mup gene family. Using the offspring of wild-caught mice, we examine individuality in the major urinary protein (MUP scent marks at the DNA, RNA and protein levels. We show that individuality arises through a combination of variation at amino acid coding sites and differential transcription of central Mup genes across individuals, and we identify eSNPs in promoters. There is no evidence of post-transcriptional processes influencing phenotypic diversity as transcripts accurately predict the relative abundance of proteins in urine samples. The match between transcripts and urine samples taken six months earlier also emphasizes that the proportional relationships across central MUP isoforms in urine is stable. Balancing selection maintains coding variants at moderate frequencies, though pheromone diversity appears limited by interactions with vomeronasal receptors. We find that differential transcription of the central Mup paralogs within and between individuals significantly increases the individuality of pheromone blends. Balancing selection on gene regulation allows for increased individuality via combinatorial diversity in a limited number of pheromones.

  11. Identification of a novel Leucine-rich repeat protein and candidate PP1 regulatory subunit expressed in developing spermatids

    Directory of Open Access Journals (Sweden)

    Sperry Ann O

    2008-01-01

    . TLRR is homologous to a class of regulatory subunits for PP1, a central phosphatase in the reversible phosphorylation of proteins that is key to modulation of many intracellular processes. TLRR may serve to target this important signaling molecule near the nucleus of developing spermatids in order to control the cellular rearrangements of spermiogenesis.

  12. A Gammaherpesvirus Complement Regulatory Protein Promotes Initiation of Infection by Activation of Protein Kinase Akt/PKB

    Science.gov (United States)

    Steer, Beatrix; Adler, Barbara; Jonjic, Stipan; Stewart, James P.; Adler, Heiko

    2010-01-01

    Background Viruses have evolved to evade the host's complement system. The open reading frames 4 (ORF4) of gammaherpesviruses encode homologs of regulators of complement activation (RCA) proteins, which inhibit complement activation at the level of C3 and C4 deposition. Besides complement regulation, these proteins are involved in heparan sulfate and glycosaminoglycan binding, and in case of MHV-68, also in viral DNA synthesis in macrophages. Methodology/Principal Findings Here, we made use of MHV-68 to study the role of ORF4 during infection of fibroblasts. While attachment and penetration of virions lacking the RCA protein were not affected, we observed a delayed delivery of the viral genome to the nucleus of infected cells. Analysis of the phosphorylation status of a variety of kinases revealed a significant reduction in phosphorylation of the protein kinase Akt in cells infected with ORF4 mutant virus, when compared to cells infected with wt virus. Consistent with a role of Akt activation in initial stages of infection, inhibition of Akt signaling in wt virus infected cells resulted in a phenotype resembling the phenotype of the ORF4 mutant virus, and activation of Akt by addition of insulin partially reversed the phenotype of the ORF4 mutant virus. Importantly, the homologous ORF4 of KSHV was able to rescue the phenotype of the MHV-68 ORF4 mutant, indicating that ORF4 is functionally conserved and that ORF4 of KSHV might have a similar function in infection initiation. Conclusions/Significance In summary, our studies demonstrate that ORF4 contributes to efficient infection by activation of the protein kinase Akt and thus reveal a novel function of a gammaherpesvirus RCA protein. PMID:20657771

  13. The RFA regulatory sequence-binding protein in the promoter of prostate-specific antigen gene

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    To assure what sequence associated with the androgen regulation, a 15 bp region at the upstream of the ARE of prostate-specific antigen (PSA) promoter, termed RFA, was found indispensable for androgen receptor (AR)-mediated transactivation of PSA promoter. In transfection and CAT assays, some nucleotides substitution in RFA could significantly decrease the androgen inducibility for PSA promoter. The in vitro DNA binding assay demonstrated that RFA bound specifically with some non-receptor protein factors in prostate cell nucleus, but the mutant type of RFA lost this ability, so RFA might be a novel accessory cis-element. The RFA-binding proteins were isolated and purified by affinity chromatography using RFA probes. SDS-PAGE and preliminary protein identification showed these proteins possessed sequence high homology with multifunctional protein heterogeneous nuclear ribonucleoprotein A1, A2 (hnRNP A1, A2). RFA-binding proteins possibly cooperate with AR-mediated transactivation for PSA promoter as coactivator. The study results will facilitate further understanding the mechanism and tissue specificity of PSA promoter.

  14. pH-Regulatory Proteins as Potential Targets in Breast Cancer

    DEFF Research Database (Denmark)

    Andersen, Anne Poder

    tissues. The focus of the present PhD study is on understanding the mechanisms through which pH-regulatory transporters are regulated by the breast tumor microenvironment, and how these transporters in turn favor cancer progression. In Paper I, we summarized the recent knowledge on the dynamic...... exhibit distinct spatial organization during 3D growth of MCF-7 and MDA-MB-231 breast cancer cells. By pharmacological inhibition and stable shRNA-mediated knockdown, we addressed the specific contributions of the transporters to spheroid growth and show that the specific transporters contribute to breast...... cancer spheroid growth in a cell-type dependent manner, with MCT1 and NBCn1 playing particular important roles in MCF-7 cells and NHE1 in MDA-MB-231 cells. In Papers III-IV we employed mouse models to study the functional relevance and the relative roles of NHE1, NBCn1 and MCT4 in breast cancer...

  15. Interleukin-1 family cytokines and their regulatory proteins in normal pregnancy and pre-eclampsia.

    Science.gov (United States)

    Southcombe, J H; Redman, C W G; Sargent, I L; Granne, I

    2015-09-01

    Maternal systemic inflammation is a feature of pre-eclampsia, a condition in pregnancy characterized by hypertension and proteinuria. Pre-eclampsia is caused by the placenta; many placental factors contribute to the syndrome's progression, and proinflammatory cytokines have been identified previously as one such mediator. The interleukin (IL)-1 family of cytokines are key regulators of the inflammatory network, and two naturally occurring regulatory molecules for IL-1 family cytokines, IL-1RA and sST2, have been found previously to be elevated in maternal blood from women with pre-eclampsia. Here we investigate more recently identified IL-1 family cytokines and regulatory molecules, IL-1RAcP, IL-37, IL-18BP, IL-36α/β/γ/Ra and IL-38 in pre-eclampsia. Pregnant women have more circulating IL-18BP and IL-36Ra than non-pregnant women, and sIL-1RAcP is elevated from women with pre-eclampsia compared to normal pregnancies. The placenta expresses all the molecules, and IL-37 and IL-18BP are up-regulated significantly in pre-eclampsia placentas compared to those from normal pregnancies. Together, these changes contribute to the required inhibition of maternal systemic cytotoxic immunity in normal pregnancy; however, in pre-eclampsia the same profile is not seen. Interestingly, the increased circulating levels of sIL-1RAcP and increased placental IL-18BP and IL-37, the latter of which we show to be induced by hypoxic damage to the placenta, are all factors which are anti-inflammatory. While the placenta is often held responsible for the damage and clinical symptoms of pre-eclampsia by the research community, here we show that the pre-eclampsia placenta is also trying to prevent inflammatory damage to the mother.

  16. Conservation of protein abundance patterns reveals the regulatory architecture of the EGFR-MAPK pathway.

    Science.gov (United States)

    Shi, Tujin; Niepel, Mario; McDermott, Jason E; Gao, Yuqian; Nicora, Carrie D; Chrisler, William B; Markillie, Lye M; Petyuk, Vladislav A; Smith, Richard D; Rodland, Karin D; Sorger, Peter K; Qian, Wei-Jun; Wiley, H Steven

    2016-07-12

    Various genetic mutations associated with cancer are known to alter cell signaling, but it is not clear whether they dysregulate signaling pathways by altering the abundance of pathway proteins. Using a combination of RNA sequencing and ultrasensitive targeted proteomics, we defined the primary components-16 core proteins and 10 feedback regulators-of the epidermal growth factor receptor (EGFR)-mitogen-activated protein kinase (MAPK) pathway in normal human mammary epithelial cells and then quantified their absolute abundance across a panel of normal and breast cancer cell lines as well as fibroblasts. We found that core pathway proteins were present at very similar concentrations across all cell types, with a variance similar to that of proteins previously shown to display conserved abundances across species. In contrast, EGFR and transcriptionally controlled feedback regulators were present at highly variable concentrations. The absolute abundance of most core proteins was between 50,000 and 70,000 copies per cell, but the adaptors SOS1, SOS2, and GAB1 were found at far lower amounts (2000 to 5000 copies per cell). MAPK signaling showed saturation in all cells between 3000 and 10,000 occupied EGFRs, consistent with the idea that adaptors limit signaling. Our results suggest that the relative stoichiometry of core MAPK pathway proteins is very similar across different cell types, with cell-specific differences mostly restricted to variable amounts of feedback regulators and receptors. The low abundance of adaptors relative to EGFR could be responsible for previous observations that only a fraction of total cell surface EGFR is capable of rapid endocytosis, high-affinity binding, and mitogenic signaling.

  17. CD55 is a key complement regulatory protein that counteracts complement-mediated inactivation of Newcastle Disease Virus.

    Science.gov (United States)

    Rangaswamy, Udaya S; Cotter, Christopher R; Cheng, Xing; Jin, Hong; Chen, Zhongying

    2016-08-01

    Newcastle disease virus (NDV) is being developed as an oncolytic virus for virotherapy. In this study we analysed the regulation of complement-mediated inactivation of a recombinant NDV in different host cells. NDV grown in human cells was less sensitive to complement-mediated virus inactivation than NDV grown in embryonated chicken eggs. Additionally, NDV produced from HeLa-S3 cells is more resistant to complement than NDV from 293F cells, which correlated with higher expression and incorporation of complement regulatory proteins (CD46, CD55 and CD59) into virions from HeLa-S3 cells. Further analysis of the recombinant NDVs individually expressing the three CD molecules showed that CD55 is the most potent in counteracting complement-mediated virus inactivation. The results provide important information on selecting NDV manufacture substrate to mitigate complement-mediated virus inactivation.

  18. The regulatory beta-subunit of protein kinase CK2 regulates cell-cycle progression at the onset of mitosis

    DEFF Research Database (Denmark)

    Yde, C W; Olsen, B B; Meek, D

    2008-01-01

    Cell-cycle transition from the G(2) phase into mitosis is regulated by the cyclin-dependent protein kinase 1 (CDK1) in complex with cyclin B. CDK1 activity is controlled by both inhibitory phosphorylation, catalysed by the Myt1 and Wee1 kinases, and activating dephosphorylation, mediated by the CDC...... interference results in delayed cell-cycle progression at the onset of mitosis. Knockdown of CK2beta causes stabilization of Wee1 and increased phosphorylation of CDK1 at the inhibitory Tyr15. PLK1-Wee1 association is an essential event in the degradation of Wee1 in unperturbed cell cycle. We have found...... regulatory subunit, identifying it as a new component of signaling pathways that regulate cell-cycle progression at the entry of mitosis.Oncogene advance online publication, 12 May 2008; doi:10.1038/onc.2008.146....

  19. The iron regulatory capability of the major protein participants in prevalent neurodegenerative disorders

    Directory of Open Access Journals (Sweden)

    Bruce Xue Wen Wong

    2014-04-01

    Full Text Available As with most bioavailable transition metals, iron is essential for many metabolic processes required by the cell but when left unregulated is implicated as a potent source of reactive oxygen species. It is uncertain whether the brain’s evident vulnerability to reactive species-induced oxidative stress is caused by a reduced capability in cellular response or an increased metabolic activity. Either way, dys-regulated iron levels appear to be involved in oxidative stress provoked neurodegeneration. As in peripheral iron management, cells within the central nervous system tightly regulate iron homeostasis via responsive expression of select proteins required for iron flux, transport and storage. Recently proteins directly implicated in the most prevalent neurodegenerative diseases, such as amyloid-β precursor protein, tau, α-synuclein, prion protein and huntingtin, have been connected to neuronal iron homeostatic control. This suggests that disrupted expression, processing or location of these proteins may result in a failure of their cellular iron homeostatic roles and augment the common underlying susceptibility to neuronal oxidative damage that is triggered in neurodegenerative disease.

  20. Purification and binding analysis of the nitrogen fixation regulatory NifA protein from Azospirillum brasilense

    Directory of Open Access Journals (Sweden)

    L.M.P. Passaglia

    1998-11-01

    Full Text Available NifA protein activates transcription of nitrogen fixation operons by the alternative sigma54 holoenzyme form of RNA polymerase. This protein binds to a well-defined upstream activator sequence (UAS located at the -200/-100 position of nif promoters with the consensus motif TGT-N10-ACA. NifA of Azospirillum brasilense was purified in the form of a glutathione-S-transferase (GST-NifA fusion protein and proteolytic release of GST yielded inactive and partially soluble NifA. However, the purified NifA was able to induce the production of specific anti-A. brasilense NifA-antiserum that recognized NifA from A. brasilense but not from K. pneumoniae. Both GST-NifA and NifA expressed from the E. coli tac promoter are able to activate transcription from the nifHDK promoter but only in an A. brasilense background. In order to investigate the mechanism that regulates NifA binding capacity we have used E. coli total protein extracts expressing A. brasilense nifA in mobility shift assays. DNA fragments carrying the two overlapping, wild-type or mutated UAS motifs present in the nifH promoter region revealed a retarded band of related size. These data show that the binding activity present in the C-terminal domain of A. brasilense NifA protein is still functional even in the presence of oxygen.

  1. MAPA distinguishes genotype-specific variability of highly similar regulatory protein isoforms in potato tuber.

    Science.gov (United States)

    Hoehenwarter, Wolfgang; Larhlimi, Abdelhalim; Hummel, Jan; Egelhofer, Volker; Selbig, Joachim; van Dongen, Joost T; Wienkoop, Stefanie; Weckwerth, Wolfram

    2011-07-01

    Mass Accuracy Precursor Alignment is a fast and flexible method for comparative proteome analysis that allows the comparison of unprecedented numbers of shotgun proteomics analyses on a personal computer in a matter of hours. We compared 183 LC-MS analyses and more than 2 million MS/MS spectra and could define and separate the proteomic phenotypes of field grown tubers of 12 tetraploid cultivars of the crop plant Solanum tuberosum. Protein isoforms of patatin as well as other major gene families such as lipoxygenase and cysteine protease inhibitor that regulate tuber development were found to be the primary source of variability between the cultivars. This suggests that differentially expressed protein isoforms modulate genotype specific tuber development and the plant phenotype. We properly assigned the measured abundance of tryptic peptides to different protein isoforms that share extensive stretches of primary structure and thus inferred their abundance. Peptides unique to different protein isoforms were used to classify the remaining peptides assigned to the entire subset of isoforms based on a common abundance profile using multivariate statistical procedures. We identified nearly 4000 proteins which we used for quantitative functional annotation making this the most extensive study of the tuber proteome to date.

  2. Purification and binding analysis of the nitrogen fixation regulatory NifA protein from Azospirillum brasilense.

    Science.gov (United States)

    Passaglia, L M; Van Soom, C; Schrank, A; Schrank, I S

    1998-11-01

    NifA protein activates transcription of nitrogen fixation operons by the alternative sigma 54 holoenzyme form of RNA polymerase. This protein binds to a well-defined upstream activator sequence (UAS) located at the -200/-100 position of nif promoters with the consensus motif TGT-N10-ACA. NifA of Azospirillum brasilense was purified in the form of a glutathione-S-transferase (GST)-NifA fusion protein and proteolytic release of GST yielded inactive and partially soluble NifA. However, the purified NifA was able to induce the production of specific anti-A. brasilense NifA-antiserum that recognized NifA from A. brasilense but not from K. pneumoniae. Both GST-NifA and NifA expressed from the E. coli tac promoter are able to activate transcription from the nifHDK promoter but only in an A. brasilense background. In order to investigate the mechanism that regulates NifA binding capacity we have used E. coli total protein extracts expressing A. brasilense nifA in mobility shift assays. DNA fragments carrying the two overlapping, wild-type or mutated UAS motifs present in the nifH promoter region revealed a retarded band of related size. These data show that the binding activity present in the C-terminal domain of A. brasilense NifA protein is still functional even in the presence of oxygen.

  3. Properties of the phage-shock-protein (Psp) regulatory complex that govern signal transduction and induction of the Psp response in Escherichia coli

    OpenAIRE

    Jovanovic, Goran; Engl, Christoph; Mayhew, Antony J.; Burrows, Patricia C.; Buck, Martin

    2010-01-01

    The phage-shock-protein (Psp) response maintains the proton-motive force (pmf) under extracytoplasmic stress conditions that impair the inner membrane (IM) in bacterial cells. In Escherichia coli transcription of the pspABCDE and pspG genes requires activation of σ 54-RNA polymerase by the enhancer-binding protein PspF. A regulatory network comprising PspF–A–C–B–ArcB controls psp expression. One key regulatory point is the negative control of PspF imposed by its binding to PspA. It has been p...

  4. Complement and membrane-bound complement regulatory proteins as biomarkers and therapeutic targets for autoimmune inflammatory disorders, RA and SLE.

    Science.gov (United States)

    Das, Nibhriti

    2015-11-01

    Complement system is a major effecter system of the innate immunity that bridges with adaptive immunity. The system consists of about 40 humoral and cell surface proteins that include zymogens, receptors and regulators. The zymogens get activated in a cascade fashion by antigen-antibody complex, antigen alone or by polymannans, respectively, by the classical, alternative and mannose binding lectin (MBL) pathways. The ongoing research on complement regulators and complement receptors suggest key role of these proteins in the initiation, regulation and effecter mechanisms of the innate and adaptive immunity. Although, the complement system provides the first line of defence against the invading pathogens, its aberrant uncontrolled activation causes extensive self tissue injury. A large number of humoral and cell surface complement regulatory protein keep the system well-regulated in healthy individuals. Complement profiling had brought important information on the pathophysiology of several infectious and chronic inflammatory disorders. In view of the diversity of the clinical disorders involving abnormal complement activity or regulation, which include both acute and chronic diseases that affect a wide range of organs, diverse yet specifically tailored therapeutic approaches may be needed to shift complement back into balance. This brief review discusses on the complement system, its functions and its importance as biomarkers and therapeutic targets for autoimmune diseases with focus on SLE and RA.

  5. Stress-evoked tyrosine phosphorylation of signal regulatory protein α regulates behavioral immobility in the forced swim test.

    Science.gov (United States)

    Ohnishi, Hiroshi; Murata, Takaaki; Kusakari, Shinya; Hayashi, Yuriko; Takao, Keizo; Maruyama, Toshi; Ago, Yukio; Koda, Ken; Jin, Feng-Jie; Okawa, Katsuya; Oldenborg, Per-Arne; Okazawa, Hideki; Murata, Yoji; Furuya, Nobuhiko; Matsuda, Toshio; Miyakawa, Tsuyoshi; Matozaki, Takashi

    2010-08-01

    Severe stress induces changes in neuronal function that are implicated in stress-related disorders such as depression. The molecular mechanisms underlying the response of the brain to stress remain primarily unknown, however. Signal regulatory protein alpha (SIRPalpha) is an Ig-superfamily protein that undergoes tyrosine phosphorylation and binds the protein tyrosine phosphatase Shp2. Here we show that mice expressing a form of SIRPalpha that lacks most of the cytoplasmic region manifest prolonged immobility (depression-like behavior) in the forced swim (FS) test. FS stress induced marked tyrosine phosphorylation of SIRPalpha in the brain of wild-type mice through activation of Src family kinases. The SIRPalpha ligand CD47 was important for such SIRPalpha phosphorylation, and CD47-deficient mice also manifested prolonged immobility in the FS test. Moreover, FS stress-induced tyrosine phosphorylation of both the NR2B subunit of the NMDA subtype of glutamate receptor and the K+-channel subunit Kvbeta2 was regulated by SIRPalpha. Thus, tyrosine phosphorylation of SIRPalpha is important for regulation of depression-like behavior in the response of the brain to stress.

  6. Functional analysis of membrane-bound complement regulatory protein on T-cell immune response in ginbuna crucian carp.

    Science.gov (United States)

    Nur, Indriyani; Abdelkhalek, Nevien K; Motobe, Shiori; Nakamura, Ryota; Tsujikura, Masakazu; Somamoto, Tomonori; Nakao, Miki

    2016-02-01

    Complements have long been considered to be a pivotal component in innate immunity. Recent researches, however, highlight novel roles of complements in T-cell-mediated adaptive immunity. Membrane-bound complement regulatory protein CD46, a costimulatory protein for T cells, is a key molecule for T-cell immunomodulation. Teleost CD46-like molecule, termed Tecrem, has been newly identified in common carp and shown to function as a complement regulator. However, it remains unclear whether Tecrem is involved in T-cell immune response. We investigated Tecrem function related to T-cell responses in ginbuna crucian carp. Ginbuna Tecrem (gTecrem) proteins were detected by immunoprecipitation using anti-common carp Tecrem monoclonal antibody (mAb) and were ubiquitously expressed on blood cells including CD8α(+) and CD4(+) lymphocytes. gTecrem expression on leucocyte surface was enhanced after stimulation with the T-cell mitogen, phytohaemagglutinin (PHA). Coculture with the anti-Tecrem mAb significantly inhibited the proliferative activity of PHA-stimulated peripheral blood lymphocytes, suggesting that cross-linking of Tecrems on T-cells interferes with a signal transduction pathway for T-cell activation. These findings indicate that Tecrem may act as a T-cell moderator and imply that the complement system in teleost, as well as mammals, plays an important role for linking adaptive and innate immunity.

  7. Xanthohumol Improves Diet-induced Obesity and Fatty Liver by Suppressing Sterol Regulatory Element-binding Protein (SREBP) Activation.

    Science.gov (United States)

    Miyata, Shingo; Inoue, Jun; Shimizu, Makoto; Sato, Ryuichiro

    2015-08-14

    Sterol regulatory element-binding proteins (SREBPs) are key transcription factors that stimulate the expression of genes involved in fatty acid and cholesterol biosynthesis. Here, we demonstrate that a prenylated flavonoid in hops, xanthohumol (XN), is a novel SREBP inactivator that reduces the de novo synthesis of fatty acid and cholesterol. XN independently suppressed the maturation of SREBPs of insulin-induced genes in a manner different from sterols. Our results suggest that XN impairs the endoplasmic reticulum-to-Golgi translocation of the SREBP cleavage-activating protein (SCAP)-SREBP complex by binding to Sec23/24 and blocking SCAP/SREBP incorporation into common coated protein II vesicles. Furthermore, in diet-induced obese mice, dietary XN suppressed SREBP-1 target gene expression in the liver accompanied by a reduction of the mature form of hepatic SREBP-1, and it inhibited the development of obesity and hepatic steatosis. Altogether, our data suggest that XN attenuates the function of SREBP-1 by repressing its maturation and that it has the potential of becoming a nutraceutical food or pharmacological agent for improving metabolic syndrome.

  8. Xanthohumol Improves Diet-induced Obesity and Fatty Liver by Suppressing Sterol Regulatory Element-binding Protein (SREBP) Activation*

    Science.gov (United States)

    Miyata, Shingo; Inoue, Jun; Shimizu, Makoto; Sato, Ryuichiro

    2015-01-01

    Sterol regulatory element-binding proteins (SREBPs) are key transcription factors that stimulate the expression of genes involved in fatty acid and cholesterol biosynthesis. Here, we demonstrate that a prenylated flavonoid in hops, xanthohumol (XN), is a novel SREBP inactivator that reduces the de novo synthesis of fatty acid and cholesterol. XN independently suppressed the maturation of SREBPs of insulin-induced genes in a manner different from sterols. Our results suggest that XN impairs the endoplasmic reticulum-to-Golgi translocation of the SREBP cleavage-activating protein (SCAP)-SREBP complex by binding to Sec23/24 and blocking SCAP/SREBP incorporation into common coated protein II vesicles. Furthermore, in diet-induced obese mice, dietary XN suppressed SREBP-1 target gene expression in the liver accompanied by a reduction of the mature form of hepatic SREBP-1, and it inhibited the development of obesity and hepatic steatosis. Altogether, our data suggest that XN attenuates the function of SREBP-1 by repressing its maturation and that it has the potential of becoming a nutraceutical food or pharmacological agent for improving metabolic syndrome. PMID:26140926

  9. Structural and dynamic characterization of eukaryotic gene regulatory protein domains in solution

    Energy Technology Data Exchange (ETDEWEB)

    Lee, A L [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry

    1996-05-01

    Solution NMR was primarily used to characterize structure and dynamics in two different eukaryotic protein systems: the {delta}-Al-{var_epsilon} activation domain from c-jun and the Drosophila RNA-binding protein Sex-lethal. The second system is the Drosophila Sex-lethal (Sxl) protein, an RNA-binding protein which is the ``master switch`` in sex determination. Sxl contains two adjacent RNA-binding domains (RBDs) of the RNP consensus-type. The NMR spectrum of the second RBD (Sxl-RBD2) was assigned using multidimensional heteronuclear NMR, and an intermediate-resolution family of structures was calculated from primarily NOE distance restraints. The overall fold was determined to be similar to other RBDs: a {beta}{alpha}{beta}-{beta}{alpha}{beta} pattern of secondary structure, with the two helices packed against a 4-stranded anti-parallel {beta}-sheet. In addition {sup 15}N T{sub 1}, T{sub 2}, and {sup 15}N/{sup 1}H NOE relaxation measurements were carried out to characterize the backbone dynamics of Sxl-RBD2 in solution. RNA corresponding to the polypyrimidine tract of transformer pre-mRNA was generated and titrated into 3 different Sxl-RBD protein constructs. Combining Sxl-RBD1+2 (bht RBDs) with this RNA formed a specific, high affinity protein/RNA complex that is amenable to further NMR characterization. The backbone {sup 1}H, {sup 13}C, and {sup 15}N resonances of Sxl-RBD1+2 were assigned using a triple-resonance approach, and {sup 15}N relaxation experiments were carried out to characterize the backbone dynamics of this complex. The changes in chemical shift in Sxl-RBD1+2 upon binding RNA are observed using Sxl-RBD2 as a substitute for unbound Sxl-RBD1+2. This allowed the binding interface to be qualitatively mapped for the second domain.

  10. Catabolism of host-derived compounds during extracellular bacterial infections.

    Science.gov (United States)

    Meadows, Jamie A; Wargo, Matthew J

    2014-02-01

    Efficient catabolism of host-derived compounds is essential for bacterial survival and virulence. While these links in intracellular bacteria are well studied, such studies in extracellular bacteria lag behind, mostly for technical reasons. The field has identified important metabolic pathways, but the mechanisms by which they impact infection and in particular, establishing the importance of a compound's catabolism versus alternate metabolic roles has been difficult. In this review we will examine evidence for catabolism during extracellular bacterial infections in animals and known or potential roles in virulence. In the process, we point out key gaps in the field that will require new or newly adapted techniques.

  11. Quercetin and vitamin E attenuate Bonny Light crude oil-induced alterations in testicular apoptosis, stress proteins and steroidogenic acute regulatory protein in Wistar rats.

    Science.gov (United States)

    Ebokaiwe, Azubuike P; Mathur, Premendu P; Farombi, Ebenezer O

    2016-10-01

    Studies have shown the reproductive effects of Bonny Light crude oil (BLCO) via the mechanism of oxidative stress and testicular apoptosis. We investigated the protective role of quercetin and vitamin E on BLCO-induced testicular apoptosis. Experimental rats were divided into four groups of four each. Animals were orally administered 2 ml/kg corn oil (control: group 1), BLCO-800 mg/kg body weight + 10 mg/kg quercetin (group 2), BLCO-800 mg/kg body weight + 50 mg/kg vitamin E (group 3) and BLCO-800 mg/kg body weight only (group 4) for 7 d. Protein levels of caspase 3, FasL, NF-kB, steroidogenic acute regulatory protein and stress response proteins were determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Immunofluorescence staining was used to quantify the expression of caspase 3, FasL and NF-kB. Apoptosis was quantified by the terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay. Administration of BLCO resulted in a significant increase in the levels of stress response proteins and apoptosis-related proteins by 50% and above after 7 d following BLCO exposure and a concomitant increase in expression of caspase 3, FasL and NF-kB expression by immunofluorescence staining. Apoptosis showed a significant increase in TUNEL positive cells. Co-administration with quercetin or vitamin E reversed BLCO-induced apoptosis and levels of stress protein, relative to control. These findings suggest that quercetin and vitamin E may confer protection against BLCO-induced testicular oxidative stress-related apoptosis.

  12. High-yield soluble expression, purification and characterization of human steroidogenic acute regulatory protein (StAR) fused to a cleavable Maltose-Binding Protein (MBP).

    Science.gov (United States)

    Sluchanko, Nikolai N; Tugaeva, Kristina V; Faletrov, Yaroslav V; Levitsky, Dmitrii I

    2016-03-01

    Steroidogenic acute regulatory protein (StAR) is responsible for the rapid delivery of cholesterol to mitochondria where the lipid serves as a source for steroid hormones biosynthesis in adrenals and gonads. Despite many successful investigations, current understanding of the mechanism of StAR action is far from being completely clear. StAR was mostly obtained using denaturation/renaturation or in minor quantities in a soluble form at decreased temperatures that, presumably, limited the possibilities for its consequent detailed exploration. In our hands, existing StAR expression constructs could be bacterially expressed almost exclusively as insoluble forms, even upon decreased expression temperatures and in specific strains of Escherichia coli, and isolated protein tended to aggregate and was difficult to handle. To maximize the yield of soluble protein, optimized StAR sequence encompassing functional domain STARD1 (residues 66-285) was fused to the C-terminus of His-tagged Maltose-Binding Protein (MBP) with the possibility to cleave off the whole tag by 3C protease. The developed protocol of expression and purification comprising of a combination of subtractive immobilized metal affinity chromatography (IMAC) and size-exclusion chromatography allowed us to obtain up to 25 mg/1 L culture of completely soluble StAR protein, which was (i) homogenous according to SDS-PAGE, (ii) gave a single symmetrical peak on a gel-filtration, (iii) showed the characteristic CD spectrum and (iv) pH-dependent ability to bind a fluorescently-labeled cholesterol analogue. We conclude that our strategy provides fully soluble and native StAR protein which in future could be efficiently used for biotechnology and drug discovery aimed at modulation of steroids production.

  13. Conservation of protein abundance patterns reveals the regulatory architecture of the EGFR-MAPK pathway

    Energy Technology Data Exchange (ETDEWEB)

    Shi, T.; Niepel, M.; McDermott, J. E.; Gao, Y.; Nicora, C. D.; Chrisler, W. B.; Markillie, L. M.; Petyuk, V. A.; Smith, R. D.; Rodland, K. D.; Sorger, P. K.; Qian, W. -J.; Wiley, H. S.

    2016-07-12

    It is not known whether cancer cells generally show quantitative differences in the expression of signaling pathway proteins that could dysregulate signal transduction. To explore this issue, we first defined the primary components of the EGF-MAPK pathway in normal human mammary epithelial cells, identifying 16 core proteins and 10 feedback regulators. We then quantified their absolute abundance across a panel of normal and cancer cell lines. We found that core pathway proteins were expressed at very similar levels across all cell types. In contrast, the EGFR and transcriptionally controlled feedback regulators were expressed at highly variable levels. The absolute abundance of most core pathway proteins was between 50,000- 70,000 copies per cell, but the adaptors SOS1, SOS2, and GAB1 were found at far lower levels (2,000-5,000 per cell). MAPK signaling showed saturation in all cells between 3,000-10,000 occupied EGFR, consistent with the idea that low adaptor levels limit signaling. Our results suggest that the core MAPK pathway is essentially invariant across different cell types, with cell- specific differences in signaling likely due to variable levels of feedback regulators. The low abundance of adaptors relative to the EGFR could be responsible for previous observation of saturable signaling, endocytosis, and high affinity EGFR.

  14. Identification of Novel Targets of the Human Cell Cycle Regulatory Protein Cdc34

    Science.gov (United States)

    1999-07-01

    results in a protein unable to complement a cdc34 mutation stages of spermatids and spermatozoa . In contrast, the repres- (34, 64). Comparable...described forms -> [ , i zn in Materials and Methods. Cotransfection of full-length hICERI3y (fly) or IgG heaivy pCS2MT-ICERIIy 1-33 (mini-lIy) with

  15. Bovine proteins containing poly-glutamine repeats are often polymorphic and enriched for components of transcriptional regulatory complexes

    LENUS (Irish Health Repository)

    Whan, Vicki

    2010-11-23

    Abstract Background About forty human diseases are caused by repeat instability mutations. A distinct subset of these diseases is the result of extreme expansions of polymorphic trinucleotide repeats; typically CAG repeats encoding poly-glutamine (poly-Q) tracts in proteins. Polymorphic repeat length variation is also apparent in human poly-Q encoding genes from normal individuals. As these coding sequence repeats are subject to selection in mammals, it has been suggested that normal variations in some of these typically highly conserved genes are implicated in morphological differences between species and phenotypic variations within species. At present, poly-Q encoding genes in non-human mammalian species are poorly documented, as are their functions and propensities for polymorphic variation. Results The current investigation identified 178 bovine poly-Q encoding genes (Q ≥ 5) and within this group, 26 genes with orthologs in both human and mouse that did not contain poly-Q repeats. The bovine poly-Q encoding genes typically had ubiquitous expression patterns although there was bias towards expression in epithelia, brain and testes. They were also characterised by unusually large sizes. Analysis of gene ontology terms revealed that the encoded proteins were strongly enriched for functions associated with transcriptional regulation and many contributed to physical interaction networks in the nucleus where they presumably act cooperatively in transcriptional regulatory complexes. In addition, the coding sequence CAG repeats in some bovine genes impacted mRNA splicing thereby generating unusual transcriptional diversity, which in at least one instance was tissue-specific. The poly-Q encoding genes were prioritised using multiple criteria for their likelihood of being polymorphic and then the highest ranking group was experimentally tested for polymorphic variation within a cattle diversity panel. Extensive and meiotically stable variation was identified

  16. Bovine proteins containing poly-glutamine repeats are often polymorphic and enriched for components of transcriptional regulatory complexes

    Directory of Open Access Journals (Sweden)

    Barendse William

    2010-11-01

    Full Text Available Abstract Background About forty human diseases are caused by repeat instability mutations. A distinct subset of these diseases is the result of extreme expansions of polymorphic trinucleotide repeats; typically CAG repeats encoding poly-glutamine (poly-Q tracts in proteins. Polymorphic repeat length variation is also apparent in human poly-Q encoding genes from normal individuals. As these coding sequence repeats are subject to selection in mammals, it has been suggested that normal variations in some of these typically highly conserved genes are implicated in morphological differences between species and phenotypic variations within species. At present, poly-Q encoding genes in non-human mammalian species are poorly documented, as are their functions and propensities for polymorphic variation. Results The current investigation identified 178 bovine poly-Q encoding genes (Q ≥ 5 and within this group, 26 genes with orthologs in both human and mouse that did not contain poly-Q repeats. The bovine poly-Q encoding genes typically had ubiquitous expression patterns although there was bias towards expression in epithelia, brain and testes. They were also characterised by unusually large sizes. Analysis of gene ontology terms revealed that the encoded proteins were strongly enriched for functions associated with transcriptional regulation and many contributed to physical interaction networks in the nucleus where they presumably act cooperatively in transcriptional regulatory complexes. In addition, the coding sequence CAG repeats in some bovine genes impacted mRNA splicing thereby generating unusual transcriptional diversity, which in at least one instance was tissue-specific. The poly-Q encoding genes were prioritised using multiple criteria for their likelihood of being polymorphic and then the highest ranking group was experimentally tested for polymorphic variation within a cattle diversity panel. Extensive and meiotically stable variation was

  17. Intraoperative Protein Catabolism during Propofol Anesthesia with Remifentanil:Comparing with Sevoflurane Anesthesia%丙泊酚或七氟醚复合瑞芬太尼麻醉对机体蛋白质分解代谢的影响

    Institute of Scientific and Technical Information of China (English)

    邢利卡; 张卫; 常琰子; 朱琰

    2014-01-01

    比较丙泊酚或七氟醚复合瑞芬太尼全麻维持,对行经腹会阴联合直肠癌根治术(Miles 手术)患者机体蛋白质分解代谢的影响。选择40例将要行 Miles 手术的患者,年龄25岁~65岁,ASA Ⅰ级~Ⅱ级,随机分为两组:一组接受丙泊酚复合瑞芬太尼全麻维持(P 组,n=20);另一组接受七氟醚复合瑞芬太尼全麻维持(S 组,n=20)。尿标本自手术开始切皮(0h)每小时收集一次,检测尿液中3-甲基组氨酸(3-M H)与肌酐(Cr)的比值(3-M H/Cr)。呼吸商(RQ)从手术切皮(0h)以后每小时检测一次。结果 P 组与 S 组 T2(1h ~2h)、T3(2h ~3h)的3-M H /Cr 值与 T0(0h)、T1(0h ~1h)相比,明显升高,且 P 组 T2和 T3的3-M H/Cr 值和 RQ 均比 S 组低。丙泊酚脂肪乳中的甘油三酯可能会作为供能物质被机体分解利用,从而减少体内蛋白质的分解。%This study compared the endocrine-metabolic responses and protein catabolism during gastrectomy in patients who received either sevoflurane or propofol anesthesia with remifentanil .Forty patients (ASA Ⅰ ~ Ⅱ ) aged 25 ~ 65 years undergoing abdominal perineal joint colorectal cancer radical prostatectomy (Miles operation) were randomly assigned to receive intravenous propofol anesthesia with remifentanil (n = 20) or sevoflurane anesthesia with remifentanil (n = 20) . Urine samples were collected every hour after skin incision (0h) and the urinary 3-methyl histidine :creatinine ratio (3-M H /Cr ratio) was used as a marker of protein catabolism .Respiratory quotient was measured during 1h period following skin incision .The 3-M H /Cr ratio significantly increased at 1h ~ 2h and 2h ~ 3h compared to 0 and 0h ~ 1h in both groups , but the propofol group exhibited a lower 3-M H/Cr ratio (nmol/μmol) than the sevoflurane group at 1h ~ 2h and 2h ~ 3h . A difference was observed in the respiratory quotient between the

  18. Structural and dynamic characterization of eukaryotic gene regulatory protein domains in solution

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Andrew Loyd [Univ. of California, Berkeley, CA (United States). Dept. of Chemistry

    1996-05-01

    Solution NMR was primarily used to characterize structure and dynamics in two different eukaryotic protein systems: the δ-Al-ε activation domain from c-jun and the Drosophila RNA-binding protein Sex-lethal. The second system is the Drosophila Sex-lethal (Sxl) protein, an RNA-binding protein which is the ``master switch`` in sex determination. Sxl contains two adjacent RNA-binding domains (RBDs) of the RNP consensus-type. The NMR spectrum of the second RBD (Sxl-RBD2) was assigned using multidimensional heteronuclear NMR, and an intermediate-resolution family of structures was calculated from primarily NOE distance restraints. The overall fold was determined to be similar to other RBDs: a βαβ-βαβ pattern of secondary structure, with the two helices packed against a 4-stranded anti-parallel β-sheet. In addition 15N T1, T2, and 15N/1H NOE relaxation measurements were carried out to characterize the backbone dynamics of Sxl-RBD2 in solution. RNA corresponding to the polypyrimidine tract of transformer pre-mRNA was generated and titrated into 3 different Sxl-RBD protein constructs. Combining Sxl-RBD1+2 (bht RBDs) with this RNA formed a specific, high affinity protein/RNA complex that is amenable to further NMR characterization. The backbone 1H, 13C, and 15N resonances of Sxl-RBD1+2 were assigned using a triple-resonance approach, and 15N relaxation experiments were carried out to characterize the backbone dynamics of this complex. The changes in chemical shift in Sxl-RBD1+2 upon binding RNA are observed using Sxl-RBD2 as a substitute for unbound Sxl-RBD1+2. This allowed the binding interface to be qualitatively mapped for the second domain.

  19. Control of Vibrio fischeri lux gene transcription by a cyclic AMP receptor protein-luxR protein regulatory circuit.

    OpenAIRE

    1988-01-01

    Expression of the Vibrio fischeri luminescence genes (lux genes) requires two transcriptional activators: the V. fischeri luxR gene product with autoinducer and the cyclic AMP (cAMP) receptor protein (CRP) with cAMP. It has been established that autoinducer and the luxR gene product are required for transcriptional activation of the luxICDABE operon, which contains a gene required for autoinducer synthesis and genes required for light emission. However, the role of cAMP-CRP in the induction o...

  20. Protein turnover in adipose tissue from fasted or diabetic rats

    Science.gov (United States)

    Tischler, Marc E.; Ost, Alan H.; Coffman, Julia

    1986-01-01

    Protein synthesis and degradation in vitro were compared in epididymal fat pads from animals deprived of food for 48 h or treated 6 or 12 days prior with streptozotocin to induce diabetes. Although both fasting and diabetes led to depressed (-24 to -57 percent) protein synthesis, the diminution in protein degradation (-63 to -72 percent) was even greater, so that net in vitro protein balance improved dramatically. Insulin failed to inhibit protein degradation in fat pads of these rats as it does for fed animals. Although insulin stimulated protein synthesis in fat pads of fasted and 12 day diabetic rats, the absolute change was much smaller than that seen in the fed state. The inhibition of protein degradation by leucine also seems to be less in fasted animals, probably because leucine catabolism is slower in fasting. These results show that fasting and diabetes may improve protein balance in adipose tissue but diminish the regulatory effects of insulin.

  1. Stimulatory effects of propylthiouracil on pregnenolone production through upregulation of steroidogenic acute regulatory protein expression in rat granulosa cells.

    Science.gov (United States)

    Chen, Mei-Chih; Wang, Shyi-Wu; Kan, Shu-Fen; Tsai, Shiow-Chwen; Wu, Yu-Ching; Wang, Paulus S

    2010-12-01

    Propylthiouracil (PTU) is a common and effective clinical medicine for the treatment of hyperthyroidism. Our previous study demonstrated that short-term treatment with PTU inhibits progesterone production in rat granulosa cells. However, our present results indicate that a 16-h treatment with PTU was able to stimulate pregnenolone production in rat granulosa cells, although progesterone production was diminished by PTU through inhibition of 3β-hydroxysteroid dehydrogenase. Notably, we found that PTU treatment enhanced the conversion of cholesterol into pregnenolone, whereas the protein level of the cytochrome P450 side-chain cleavage enzyme (P450scc, which is the enzyme responding to this conversion) was not affected. Interestingly, the levels of steroidogenic acute regulatory protein (StAR) in both total cell lysate and the mitochondrial fraction were significantly increased by PTU treatment. Furthermore, the binding of steroidogenic factor-1 (SF-1) to the StAR promoter region was also enhanced by PTU treatment, which suggests that PTU could upregulate StAR gene expression. In addition to SF-1 regulation, we found that mitogen-activated protein (MAP) kinase kinase activation is an important regulator of PTU-stimulated StAR protein expression, based on the effects of the MEK inhibitor PD98059. In conclusion, these results indicate that PTU plays opposite roles in the production of progesterone and its precursor, pregnenolone. The regulation of negative feedback on speeding the cholesterol transportation and pregnenolone conversion after a 16-h PTU treatment may be the mechanism explaining PTU's inhibition of progesterone production in rat granulosa cells.

  2. Interactions between Barley a-Amylases, Substrates, Inhibitors and Regulatory Proteins

    DEFF Research Database (Denmark)

    Hachem, Maher Abou; Bozonnet, Sophie; Willemoës, Martin

    2006-01-01

    Barley a-amylase binds sugars at two sites on the enzyme surface in addition to the active site. Crystallography and site-directed mutagenesis highlight the importance of aromatic residues at these surface sites as demonstrated by Kd values determined for ß-cyclodextrin by surface plasmon resonance......, a fully hydrated calcium ion at the protein interface mediates contact between inhibitor residues and the enzyme catalytic groups in a manner that depends on calcium and which can be suppressed by site-directed mutagenesis of Glu168 in BASI. Finally certain inhibitors and enzymes are targets...... of the disulphide reductase thioredoxin h that attacks a specific disulphide bond in BASI and, remarkably, reduces two different disulphide bonds in the barley monomeric and dimeric amylase inhibitors that both belong to the CM-proteins and inhibit animal a-amylase....

  3. Regulatory effect of heat shock protein 70 in stress-induced rat intestinal epithelial barrier dysfunction

    Directory of Open Access Journals (Sweden)

    Stevie Struiksma

    2009-06-01

    Full Text Available Background: Psychological stress is one of the factors associated with many human diseases; the mechanisms need to be further understood. Methods: Rats were subjected to chronic water avoid stress. Intestinal epithelial heat shock protein (HSP 70 was evaluated. The intestinal epithelial permeability was examined with Ussing chamber technique. Results: HSP70 was detected in normal intestinal epithelial cells. Psychological stress decreased HSP70 in the intestinal epithelial cells that correlated with the stress-induced intestinal epithelial hyperpermeability. Pretreatment with HSP70 abrogated stress-induced intestinal barrier dysfunction. Conclusions: Chronic stress inhibits HSP70 activity in rat intestinal epithelial layer that is associated with intestinal epithelial barrier dysfunction, which can be prevented by pretreatment with HSP70 protein.

  4. Expression of survivin, a novel apoptosis inhibitor and cell cycle regulatory protein, in human gliomas

    Institute of Scientific and Technical Information of China (English)

    焦保华; 姚志刚; 耿少梅; 左书浩

    2004-01-01

    @@ Recently, a novel anti-apoptosis gene, named survivin,was identified as a structurally unique member of the inhibitor of apoptosis protein (lAP) family. The gene is located on chromosome 17q25. Survivin is a 16.5 kDa protein that is expressed in vivo in common human cancers, but not in normal adjacent tissue,1 during the G2/M phase of the cell cycle. Survivin expression is turned off during fetal development and not found in nonneoplastic adult human tissue, and it is turned on in most common human cancers. We investigated the expression of survivin in 50 patients with human gliomas, and determined its association with cell apoptosis and cell proliferation, and its impact on tumor progression and prognosis.

  5. Functional and Developmental Analysis of CD4+CD25+ Regulatory T Cells under the Influence of Streptococcal M Protein in Rheumatic Heart Disease

    Directory of Open Access Journals (Sweden)

    Nidhal Abdul-Auhaimen

    2011-06-01

    Full Text Available The purpose of this study was to determine the role of streptococcal M protein in naturally-occurring CD4+CD25+ regulatory T cells (nTregs function and development in rheumatic heart disease in Iraqi patients. Streptococcus pyogenes was isolated for subsequent M protein extraction. Also, peripheral blood nTregs and CD4+ T cells were isolated by using Magnetic Cell Separation System. Tissue culture for isolated cells was performed in the presence and absence of M protein. Cell count was performed, and tumor necrosis factor alpha (TNF-α and interleukin-4 (IL-4 were determined in culture supernatant using ELISA system. There was a significant positive correlation (P0.05, association (r=0.353 between the mean number of nTregs and CD4+ T cells in the presence of M protein. The M protein stimulated CD4+ T cells to produce IL-4 in very little amount (<4 pg/ml in all samples. Compared to the production of IL4, TNF-α was produced in higher concentrations in the culture supernatants. The findings of the study indicate that streptococcal M protein has an important role in increasing the proliferation of CD4+CD25+regulatory T cells and CD4+ T cells. However, CD4+CD25+ regulatory T cells have lower suppressive activity against CD4+ T cells in the presence of M protein

  6. Functional and Developmental Analysis of CD4+CD25+ Regulatory T Cells under the Influence of Streptococcal M Protein in Rheumatic Heart Disease

    Science.gov (United States)

    Abdul-Auhaimena, Nidhal; Al-Kaabi, Zaman I. L

    2011-01-01

    The purpose of this study was to determine the role of streptococcal M protein in naturally-occurring CD4+CD25+ regulatory T cells (nTregs) function and development in rheumatic heart disease in Iraqi patients. Streptococcus pyogenes was isolated for subsequent M protein extraction. Also, peripheral blood nTregs and CD4+ T cells were isolated by using Magnetic Cell Separation System. Tissue culture for isolated cells was performed in the presence and absence of M protein. Cell count was performed, and tumor necrosis factor alpha (TNF-α) and interleukin-4 (IL-4) were determined in culture supernatant using ELISA system. There was a significant positive correlation (P0.05), association (r=0.353) between the mean number of nTregs and CD4+ T cells in the presence of M protein. The M protein stimulated CD4+ T cells to produce IL-4 in very little amount (<4 pg/ml) in all samples. Compared to the production of IL4, TNF-α was produced in higher concentrations in the culture supernatants. The findings of the study indicate that streptococcal M protein has an important role in increasing the proliferation of D4+CD25+regulatory T cells and CD4+ T cells. However, CD4+CD25+ regulatory T cells have lower suppressive activity against CD4+ T cells in the presence of M protein. PMID:23359747

  7. Lamins, laminopathies and disease mechanisms: Possible role for proteasomal degradation of key regulatory proteins

    Indian Academy of Sciences (India)

    Veena K Parnaik; Pankaj Chaturvedi; B H Muralikrishna

    2011-08-01

    Lamins are major structural proteins of the nucleus and are essential for nuclear integrity and organization of nuclear functions. Mutations in the human lamin genes lead to highly degenerative genetic diseases that affect a number of different tissues such as muscle, adipose or neuronal tissues, or cause premature ageing syndromes. New findings on the role of lamins in cellular signalling pathways, as well as in ubiquitin-mediated proteasomal degradation, have given important insights into possible mechanisms of pathogenesis.

  8. Functional Characterization of a Novel Pro-Apoptotic Transcription Regulatory Protein in Ovarian Cancer

    Science.gov (United States)

    2006-12-01

    Approved for Public Release; Distribution Unlimited 13. SUPPLEMENTARY NOTES Original contains colored plates: ALL DTIC reproductions will be in...region of NADE that is shown to be involved in NGF -dependent regulation of NADE-induced apoptosis [4]. NADE is a nuclear pro-apoptotic protein...and NADE share high degree of homology except between residues 72-112 of NADE, a region essential for NGF -dependent regulation of NADE-induced

  9. Transcriptional analysis of the jamaicamide gene cluster from the marine cyanobacterium Lyngbya majuscula and identification of possible regulatory proteins

    Directory of Open Access Journals (Sweden)

    Dorrestein Pieter C

    2009-12-01

    Full Text Available Abstract Background The marine cyanobacterium Lyngbya majuscula is a prolific producer of bioactive secondary metabolites. Although biosynthetic gene clusters encoding several of these compounds have been identified, little is known about how these clusters of genes are transcribed or regulated, and techniques targeting genetic manipulation in Lyngbya strains have not yet been developed. We conducted transcriptional analyses of the jamaicamide gene cluster from a Jamaican strain of Lyngbya majuscula, and isolated proteins that could be involved in jamaicamide regulation. Results An unusually long untranslated leader region of approximately 840 bp is located between the jamaicamide transcription start site (TSS and gene cluster start codon. All of the intergenic regions between the pathway ORFs were transcribed into RNA in RT-PCR experiments; however, a promoter prediction program indicated the possible presence of promoters in multiple intergenic regions. Because the functionality of these promoters could not be verified in vivo, we used a reporter gene assay in E. coli to show that several of these intergenic regions, as well as the primary promoter preceding the TSS, are capable of driving β-galactosidase production. A protein pulldown assay was also used to isolate proteins that may regulate the jamaicamide pathway. Pulldown experiments using the intergenic region upstream of jamA as a DNA probe isolated two proteins that were identified by LC-MS/MS. By BLAST analysis, one of these had close sequence identity to a regulatory protein in another cyanobacterial species. Protein comparisons suggest a possible correlation between secondary metabolism regulation and light dependent complementary chromatic adaptation. Electromobility shift assays were used to evaluate binding of the recombinant proteins to the jamaicamide promoter region. Conclusion Insights into natural product regulation in cyanobacteria are of significant value to drug discovery

  10. Increase in cell viability by polyamines through stimulation of the synthesis of ppGpp regulatory protein and ω protein of RNA polymerase in Escherichia coli.

    Science.gov (United States)

    Terui, Yusuke; Akiyama, Mariko; Sakamoto, Akihiko; Tomitori, Hideyuki; Yamamoto, Kaneyoshi; Ishihama, Akira; Igarashi, Kazuei; Kashiwagi, Keiko

    2012-02-01

    It is known that polyamines increase cell growth through stimulation of the synthesis of several kinds of proteins encoded by the so-called "polyamine modulon". We recently reported that polyamines also increase cell viability at the stationary phase of cell growth through stimulation of the synthesis of ribosome modulation factor, a component of the polyamine modulon. Accordingly, we looked for other proteins involved in cell viability whose synthesis is stimulated by polyamines. It was found that the synthesis of ppGpp regulatory protein (SpoT) and ω protein of RNA polymerase (RpoZ) was stimulated by polyamines at the level of translation. Stimulation of the synthesis of SpoT and RpoZ by polyamines was due to an inefficient initiation codon UUG in spoT mRNA and an unusual location of a Shine-Dalgarno (SD) sequence in rpoZ mRNA. Accordingly, the spoT and rpoZ genes are components of the polyamine modulon involved in cell viability. Reduced cell viability caused by polyamine deficiency was prevented by modified spoT and rpoZ genes whose synthesis was not influenced by polyamines. Under these conditions, the level of ppGpp increased in parallel with increase of SpoT protein. The results indicate that polyamine stimulation of synthesis of SpoT and RpoZ plays important roles for cell viability through stimulation of ppGpp synthesis by SpoT and modulation of RNA synthesis by ppGpp-RpoZ complex.

  11. Pathway and Enzyme Redundancy in Putrescine Catabolism in Escherichia coli

    OpenAIRE

    Schneider, Barbara L.; Reitzer, Larry

    2012-01-01

    Putrescine as the sole carbon source requires a novel catabolic pathway with glutamylated intermediates. Nitrogen limitation does not induce genes of this glutamylated putrescine (GP) pathway but instead induces genes for a putrescine catabolic pathway that starts with a transaminase-dependent deamination. We determined pathway utilization with putrescine as the sole nitrogen source by examining mutants with defects in both pathways. Blocks in both the GP and transaminase pathways were requir...

  12. Lovastatin insensitive 1, a Novel pentatricopeptide repeat protein, is a potential regulatory factor of isoprenoid biosynthesis in Arabidopsis.

    Science.gov (United States)

    Kobayashi, Keiko; Suzuki, Masashi; Tang, Jianwei; Nagata, Noriko; Ohyama, Kiyoshi; Seki, Hikaru; Kiuchi, Reiko; Kaneko, Yasuko; Nakazawa, Miki; Matsui, Minami; Matsumoto, Shogo; Yoshida, Shigeo; Muranaka, Toshiya

    2007-02-01

    Higher plants have two metabolic pathways for isoprenoid biosynthesis: the cytosolic mevalonate (MVA) pathway and the plastidal non-mevalonate (MEP) pathway. Despite the compartmentalization of these two pathways, metabolic flow occurs between them. However, little is known about the mechanisms that regulate the two pathways and the metabolic cross-talk. To identify such regulatory mechanisms, we isolated and characterized the Arabidopsis T-DNA insertion mutant lovastatin insensitive 1 (loi1), which is resistant to lovastatin and clomazone, inhibitors of the MVA and MEP pathways, respectively. The accumulation of the major products of these pathways, i.e. sterols and chlorophyll, was less affected by lovastatin and clomazone, respectively, in loi1 than in the wild type. Furthermore, the 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) activity analysis showed higher activity of HMGR in loi1-1 treated with lovastatin than that in the WT. We consider that the lovastatin-resistant phenotype of loi1-1 was derived from this post-transcriptional up-regulation of HMGR. The LOI1 gene encodes a novel pentatricopeptide repeat (PPR) protein. PPR proteins are thought to regulate the expression of genes encoded in organelle genomes by post-transcriptional regulation in mitochondria or plastids. Our results demonstrate that LOI1 is predicted to localize in mitochondria and has the ability to bind single-stranded nucleic acids. Our investigation revealed that the post-transcriptional regulation of mitochondrial RNA may be involved in isoprenoid biosynthesis in both the MVA and MEP pathways.

  13. Post-Translational Modifications of Kaposi’s Sarcoma-Associated Herpesvirus (KSHV Regulatory Proteins-SUMO and KSHV

    Directory of Open Access Journals (Sweden)

    Mel eCampbell

    2012-02-01

    Full Text Available Reactivation from a latent state is an important feature of infection and disease caused by many herpesviruses. KSHV latency can be envisioned as an outcome that is balanced between factors that promote viral gene expression and lytic replication against those that facilitate gene silencing and establish or maintain latency. A large body of work has focused on the activities of the key viral regulatory proteins involved in KSHV latent or lytic states. Moreover, recent studies have also begun to document the importance of epigenetic landscape evolution of the KSHV viral genome during latency and reactivation. However, one area of KSHV molecular virology that remains largely unanswered is the precise role of post-translational modifications on the activities of viral factors that function during latency and reactivation. In this review, we will summarize the post-translational modifications associated with three viral factors whose activities contribute to the viral state. The viral proteins discussed are the two major KSHV encoded transcription factors, K-Rta and K-bZIP (KSHV basic leucine zipper and the viral latency-associated nuclear antigen (LANA. A special emphasis will be placed on the role of the sumoylation pathway in the modulation of the KSHV lifecycle. Newly uncovered SUMO-dependent properties of LANA and K-Rta will also be presented, namely LANA histone-targeting SUMO E3 ligase activity and K-Rta SUMO-targeted ubiquitin ligase function.

  14. Regulation of steroid 5-{alpha} reductase type 2 (Srd5a2) by sterol regulatory element binding proteins and statin

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Young-Kyo [Department of Molecular Biology and Biochemistry, 3244 McGaugh Hall, University of California, UC Irvine, Irvine, CA 92697-3900 (United States); Zhu, Bing [Department of Pathology, University of Texas Medical Branch, Galveston, TX 77555-0144 (United States); Jeon, Tae-Il [Department of Molecular Biology and Biochemistry, 3244 McGaugh Hall, University of California, UC Irvine, Irvine, CA 92697-3900 (United States); Osborne, Timothy F., E-mail: tfosborn@uci.edu [Department of Molecular Biology and Biochemistry, 3244 McGaugh Hall, University of California, UC Irvine, Irvine, CA 92697-3900 (United States)

    2009-11-01

    In this study, we show that sterol regulatory element binding proteins (SREBPs) regulate expression of Srd5a2, an enzyme that catalyzes the irreversible conversion of testosterone to dihydroxytestosterone in the male reproductive tract and is highly expressed in androgen-sensitive tissues such as the prostate and skin. We show that Srd5a2 is induced in livers and prostate from mice fed a chow diet supplemented with lovastatin plus ezitimibe (L/E), which increases the activity of nuclear SREBP-2. The three fold increase in Srd5a2 mRNA mediated by L/E treatment was accompanied by the induction of SREBP-2 binding to the Srd5a2 promoter detected by a ChIP-chip assay in liver. We identified a SREBP-2 responsive region within the first 300 upstream bases of the mouse Srd5a2 promoter by co-transfection assays which contain a site that bound SREBP-2 in vitro by an EMSA. Srd5a2 protein was also induced in cells over-expressing SREBP-2 in culture. The induction of Srd5a2 through SREBP-2 provides a mechanistic explanation for why even though statin therapy is effective in reducing cholesterol levels in treating hypercholesterolemia it does not compromise androgen production in clinical studies.

  15. Piperine Induces Hepatic Low-Density Lipoprotein Receptor Expression through Proteolytic Activation of Sterol Regulatory Element-Binding Proteins.

    Directory of Open Access Journals (Sweden)

    Ayasa Ochiai

    Full Text Available Elevated plasma low-density lipoprotein (LDL cholesterol is considered as a risk factor for atherosclerosis. Because the hepatic LDL receptor (LDLR uptakes plasma lipoproteins and lowers plasma LDL cholesterol, the activation of LDLR is a promising drug target for atherosclerosis. In the present study, we identified the naturally occurring alkaloid piperine, as an inducer of LDLR gene expression by screening the effectors of human LDLR promoter. The treatment of HepG2 cells with piperine increased LDLR expression at mRNA and protein levels and stimulated LDL uptake. Subsequent luciferase reporter gene assays revealed that the mutation of sterol regulatory element-binding protein (SREBP-binding element abolished the piperine-mediated induction of LDLR promoter activity. Further, piperine treatments increased mRNA levels of several SREBP targets and mature forms of SREBPs. However, the piperine-mediated induction of the mature forms of SREBPs was not observed in SRD-15 cells, which lack insulin-induced gene-1 (Insig-1 and Insig-2. Finally, the knockdown of SREBPs completely abolished the piperine-meditated induction of LDLR gene expression in HepG2 cells, indicating that piperine stimulates the proteolytic activation of SREBP and subsequent induction of LDLR expression and activity.

  16. Piperine Induces Hepatic Low-Density Lipoprotein Receptor Expression through Proteolytic Activation of Sterol Regulatory Element-Binding Proteins.

    Science.gov (United States)

    Ochiai, Ayasa; Miyata, Shingo; Shimizu, Makoto; Inoue, Jun; Sato, Ryuichiro

    2015-01-01

    Elevated plasma low-density lipoprotein (LDL) cholesterol is considered as a risk factor for atherosclerosis. Because the hepatic LDL receptor (LDLR) uptakes plasma lipoproteins and lowers plasma LDL cholesterol, the activation of LDLR is a promising drug target for atherosclerosis. In the present study, we identified the naturally occurring alkaloid piperine, as an inducer of LDLR gene expression by screening the effectors of human LDLR promoter. The treatment of HepG2 cells with piperine increased LDLR expression at mRNA and protein levels and stimulated LDL uptake. Subsequent luciferase reporter gene assays revealed that the mutation of sterol regulatory element-binding protein (SREBP)-binding element abolished the piperine-mediated induction of LDLR promoter activity. Further, piperine treatments increased mRNA levels of several SREBP targets and mature forms of SREBPs. However, the piperine-mediated induction of the mature forms of SREBPs was not observed in SRD-15 cells, which lack insulin-induced gene-1 (Insig-1) and Insig-2. Finally, the knockdown of SREBPs completely abolished the piperine-meditated induction of LDLR gene expression in HepG2 cells, indicating that piperine stimulates the proteolytic activation of SREBP and subsequent induction of LDLR expression and activity.

  17. Preventing Phosphorylation of Sterol Regulatory Element-Binding Protein 1a by MAP-Kinases Protects Mice from Fatty Liver and Visceral Obesity

    OpenAIRE

    Jorg Kotzka; Birgit Knebel; Jutta Haas; Lorena Kremer; Sylvia Jacob; Sonja Hartwig; Ulrike Nitzgen; Dirk Muller-Wieland

    2012-01-01

    The transcription factor sterol regulatory element binding protein (SREBP)-1a plays a pivotal role in lipid metabolism. Using the SREBP-1a expressing human hepatoma cell line HepG2 we have shown previously that human SREBP-1a is phosphorylated at serine 117 by ERK-mitogen-activated protein kinases (MAPK). Using a combination of cell biology and protein chemistry approach we show that SREBP-1a is also target of other MAPK-families, i.e. c-JUN N-terminal protein kinases (JNK) or p38 stress acti...

  18. Defective jejunal and colonic salt absorption and alteredNa +/H+ exchanger 3 (NHE3) activity in NHE regulatory factor 1 (NHERF1) adaptor protein-deficient mice

    NARCIS (Netherlands)

    N. Broere (Nellie); M. Chen (Min); A. Cinar (Ayhan); A.K. Singh (Arbind); J. Hillesheim (Jutta); B. Riederer (Beat Michel); M. Lunnemann; I. Rottinghaus (Ingrid); A. Krabbenhöft (Anja); R. Engelhardt (Regina); B. Rausch; E.J. Weinman (Edward); M. Donowitz (Mark); A. Hubbard; O. Kocher (Olivier); H.R. de Jonge (Hugo); B.M. Hogema (Boris); U. Seidler (Ursula)

    2009-01-01

    textabstractWe investigated the role of the Na+/H+ exchanger regulatory factor 1 (NHERF1) on intestinal salt and water absorption, brush border membrane (BBM) morphology, and on the NHE3 mRNA expression, protein abundance, and transport activity in the murine intestine. NHERF1-deficient mice display

  19. Regulatory Effect of Bcl-2 Family Proteins in CPB-induced Cardiomyocyte Apoptosis in Dog Hearts

    Institute of Scientific and Technical Information of China (English)

    孙宗全; 张顺业; 刘立新; 哈斯朝鲁

    2002-01-01

    Summary: Whether conventional hypothermic CPB induces myocyte apoptosis in dog hearts and modulation of bcl-2, bcl-xl, bax, bad, and caspase-3 pathways in this setting was investigated. Ten healthy adult dogs were randomized into sham-operated and CPB groups. Samples of left ventricle were obtained before, during and 3 h after CPB. In situ TUNEL was used to detect apoptotic my ocytes. Immunohistochemistry and flow cytometry were employed for detection of expressions of bcl 2, bcl-xl, bax and bad proteins. Z-DEVD-AMC substrate cleavage and TBARS methods were usedto measure the activity of caspase-3 and the content of lipid peroxide in LV myocardium, respective ly. After CPB, the number of apoptotic myocytes in CPB group was significantly increased. The re-sults of immunohistichemistry demonstrated that bcl-2, bcl-xl, bax and bad proteins were constitu tionally presnt on the sarcolemma of the LV myocytes. FACS results showed that, after CPB, ex-pressions of bax and bad in CPB group were significantly upregulated, while the expressions of bcl-2 and bcl-xl were not significantly changed in both groups. The activity of caspase-3 and the content of lipid peroxide in LV myocardium in CPB group were also significantly increased after CPB. The pre-sent study shows that there exists myocardiocyte apoptosis in dog hearts undergoing conventional hy-pothermic CPB and the myocyte apoptosis is initiated by ischemia and performed during reperfusion.Moreover, the CPB-induced myocyte apoptosis was associated with upregulation of expressions of bax and bad proteins, activation of caspase-3 and increase of oxidative stress.

  20. Regulatory effect of bcl-2 family proteins in CPB-induced cardiomyocyte apoptosis in dog hearts.

    Science.gov (United States)

    Sun, Zongquan; Zhang, Shunye; Liu, Lixin; Hasichaolu

    2002-01-01

    Whether conventional hypothermic CPB induces myocyte apoptosis in dog hearts and modulation of bcl-2, bcl-xl, bax, bad, and caspase-3 pathways in this setting was investigated. Ten healthy adult dogs were randomized into sham-operated and CPB groups. Samples of left ventricle were obtained before, during and 3 h after CPB. In situ TUNEL was used to detect apoptotic myocytes. Immunohistochemistry and flow cytometry were employed for detection of expressions of bcl-2, bcl-xl, bax and bad proteins. Z-DEVD-AMC substrate cleavage and TBARS methods were used to measure the activity of caspase-3 and the content of lipid peroxide in LV myocardium, respectively. After CPB, the number of apoptotic myocytes in CPB group was significantly increased. The results of immunohistochemistry demonstrated that bcl-2, bcl-xl, bax and bad proteins were constitutionally present on the sarcolemma of the LV myocytes. FACS results showed that, after CPB, expressions of bax and bad in CPB group were significantly upregulated, while the expressions of bcl-2 and bcl-xl were not significantly changed in both groups. The activity of caspase-3 and the content of lipid peroxide in LV myocardium in CPB group were also significantly increased after CPB. The present study shows that there exists myocardiocyte apoptosis in dog hearts undergoing conventional hypothermic CPB and the myocyte apoptosis is initiated by ischemia and performed during reperfusion. Moreover, the CPB-induced myocyte apoptosis was associated with upregulation of expressions of bax and bad proteins, activation of caspase-3 and increase of oxidative stress.

  1. Phosphorylation of the regulatory beta-subunit of protein kinase CK2 by checkpoint kinase Chk1: identification of the in vitro CK2beta phosphorylation site

    DEFF Research Database (Denmark)

    Kristensen, Lars P; Larsen, Martin Røssel; Højrup, Peter;

    2004-01-01

    The regulatory beta-subunit of protein kinase CK2 mediates the formation of the CK2 tetrameric form and it has functions independent of CK2 catalytic subunit through interaction with several intracellular proteins. Recently, we have shown that CK2beta associates with the human checkpoint kinase Chk...... by the modification of Thr213 but it does require the presence of an active Chk1 kinase....

  2. Atualizações sobre beta-hidroxi-beta-metilbutirato: suplementação e efeitos sobre o catabolismo de proteínas New findings on beta-hydroxy-beta-methylbutyirate: supplementation and effects on the protein catabolism

    Directory of Open Access Journals (Sweden)

    Everson Araújo Nunes

    2008-04-01

    Full Text Available O beta-hidroxi-beta-metilbutirato, metabólito do aminoácido leucina, vem sendo utilizado como suplemento alimentar, em situações específicas, com o intuito de aumentar ou manter a massa isenta de gordura. Os relatos dos efeitos do beta-hidroxi-beta-metilbutirato em estudos recentes fizeram crescer as expectativas sobre sua utilização em casos patológicos. Também foram demonstrados melhores resultados, quando da sua ingestão, no treinamento de força em indivíduos iniciantes e em idosos. Em humanos o beta-hidroxi-beta-metilbutirato tem sido usado como agente anti-catabólico, e em modelos animais foi demonstrado ser eficaz em inibir a atividade de vias proteolíticas em células musculares de indivíduos caquéticos in vitro e in vivo. Os mecanismos participantes desses processos envolvem: a inibição da atividade do sistema ubiquitina proteossoma ATP-dependente, a inibição de vias de sinalização com participação da proteína quinase C-alfa e a diminuição da concentração citoplasmática do fator nuclear - kappa B livre, eventos relacionados ao decréscimo da proteólise em células musculares.The leucine metabolite beta-hydroxy-beta-methylbutyrate has been used as a nutritional supplement in specific situations to prevent losing or to increase lean mass. Recent studies showed interesting results of beta-hydroxy-beta-methylbutyrate supplementation in certain disease states. Better results have also been demonstrated when it is taken by starters or old individuals doing strength training. In humans, beta-hydroxy-beta-methylbutyrate has been used as an anticatabolic agent and in animal models it has been demonstrated to be effective in inhibiting the activity of the proteolytic pathways in muscle cells of extremely weak individuals in vivo and in vitro. The mechanisms that participate in this process involve: inhibition of the ATP-ubiquitin-proteasome pathway, inhibition of the signalization pathways involving protein kinase C

  3. Oxytocin receptor gene sequences in owl monkeys and other primates show remarkable interspecific regulatory and protein coding variation.

    Science.gov (United States)

    Babb, Paul L; Fernandez-Duque, Eduardo; Schurr, Theodore G

    2015-10-01

    The oxytocin (OT) hormone pathway is involved in numerous physiological processes, and one of its receptor genes (OXTR) has been implicated in pair bonding behavior in mammalian lineages. This observation is important for understanding social monogamy in primates, which occurs in only a small subset of taxa, including Azara's owl monkey (Aotus azarae). To examine the potential relationship between social monogamy and OXTR variation, we sequenced its 5' regulatory (4936bp) and coding (1167bp) regions in 25 owl monkeys from the Argentinean Gran Chaco, and examined OXTR sequences from 1092 humans from the 1000 Genomes Project. We also assessed interspecific variation of OXTR in 25 primate and rodent species that represent a set of phylogenetically and behaviorally disparate taxa. Our analysis revealed substantial variation in the putative 5' regulatory region of OXTR, with marked structural differences across primate taxa, particularly for humans and chimpanzees, which exhibited unique patterns of large motifs of dinucleotide A+T repeats upstream of the OXTR 5' UTR. In addition, we observed a large number of amino acid substitutions in the OXTR CDS region among New World primate taxa that distinguish them from Old World primates. Furthermore, primate taxa traditionally defined as socially monogamous (e.g., gibbons, owl monkeys, titi monkeys, and saki monkeys) all exhibited different amino acid motifs for their respective OXTR protein coding sequences. These findings support the notion that monogamy has evolved independently in Old World and New World primates, and that it has done so through different molecular mechanisms, not exclusively through the oxytocin pathway.

  4. Identification and characterization of a novel regulatory factor: IgA-inducing protein.

    Science.gov (United States)

    Austin, Amy S; Haas, Karen M; Naugler, Sasha M; Bajer, Anna A; Garcia-Tapia, David; Estes, D Mark

    2003-08-01

    IgA is the predominant Ig isotype in mucosal secretions and thus plays a pivotal role in host defense. The mechanisms by which IgA expression is regulated may differ among species and involve multiple pathways. Various cytokines and costimulators have been identified which regulate expression of this isotype, including IL-10, IL-2, vasoactive intestinal peptide, and TGF-beta. We have tested a wide array of known factors, but only under very limited conditions do these factors mediate substantial IgA production in vitro from bovine B cells. In response to these findings, we generated a cDNA library in a mammalian expression vector from activated cells derived from bovine gut-associated lymphoid tissues (Peyer's patch and mesenteric lymph node cells) as a source of soluble factor(s) that may regulate IgA production. We have identified a novel factor, IgA-inducing protein, which stimulates relatively high levels of IgA production in vitro following CD40 stimulation in coculture with IL-2. Our data suggest that IgA-inducing protein regulates IgA by acting as a switch or differentiation factor and is expressed in a variety of lymphoid and nonlymphoid tissues.

  5. A novel Snf2 protein maintains trans-generational regulatory states established by paramutation in maize.

    Directory of Open Access Journals (Sweden)

    Christopher J Hale

    2007-10-01

    Full Text Available Paramutations represent heritable epigenetic alterations that cause departures from Mendelian inheritance. While the mechanism responsible is largely unknown, recent results in both mouse and maize suggest paramutations are correlated with RNA molecules capable of affecting changes in gene expression patterns. In maize, multiple required to maintain repression (rmr loci stabilize these paramutant states. Here we show rmr1 encodes a novel Snf2 protein that affects both small RNA accumulation and cytosine methylation of a proximal transposon fragment at the Pl1-Rhoades allele. However, these cytosine methylation differences do not define the various epigenetic states associated with paramutations. Pedigree analyses also show RMR1 does not mediate the allelic interactions that typically establish paramutations. Strikingly, our mutant analyses show that Pl1-Rhoades RNA transcript levels are altered independently of transcription rates, implicating a post-transcriptional level of RMR1 action. These results suggest the RNA component of maize paramutation maintains small heterochromatic-like domains that can affect, via the activity of a Snf2 protein, the stability of nascent transcripts from adjacent genes by way of a cotranscriptional repression process. These findings highlight a mechanism by which alleles of endogenous loci can acquire novel expression patterns that are meiotically transmissible.

  6. Novel functions for the endocytic regulatory proteins MICAL-L1 and EHD1 in mitosis.

    Science.gov (United States)

    Reinecke, James B; Katafiasz, Dawn; Naslavsky, Naava; Caplan, Steve

    2015-01-01

    During interphase, recycling endosomes mediate the transport of internalized cargo back to the plasma membrane. However, in mitotic cells, recycling endosomes are essential for the completion of cytokinesis, the last phase of mitosis that promotes the physical separation the two daughter cells. Despite recent advances, our understanding of the molecular determinants that regulate recycling endosome dynamics during cytokinesis remains incomplete. We have previously demonstrated that Molecule Interacting with CasL Like-1 (MICAL-L1) and C-terminal Eps15 Homology Domain protein 1 (EHD1) coordinately regulate receptor transport from tubular recycling endosomes during interphase. However, their potential roles in controlling cytokinesis had not been addressed. In this study, we show that MICAL-L1 and EHD1 regulate mitosis. Depletion of either protein resulted in increased numbers of bi-nucleated cells. We provide evidence that bi-nucleation in MICAL-L1- and EHD1-depleted cells is a consequence of impaired recycling endosome transport during late cytokinesis. However, depletion of MICAL-L1, but not EHD1, resulted in aberrant chromosome alignment and lagging chromosomes, suggesting an EHD1-independent function for MICAL-L1 earlier in mitosis. Moreover, we provide evidence that MICAL-L1 and EHD1 differentially influence microtubule dynamics during early and late mitosis. Collectively, our new data suggest several unanticipated roles for MICAL-L1 and EHD1 during the cell cycle.

  7. Molecular dynamics simulations of conformation changes of HIV-1 regulatory protein on graphene

    Science.gov (United States)

    Zhao, Daohui; Li, Libo; He, Daohang; Zhou, Jian

    2016-07-01

    The fragment of viral protein R (Vpr), Vpr13-33, plays an important role in regulating nuclear importing of HIV genes through channel formation in which it adopts a leucine-zipper-like alpha-helical conformation. A recent experimental study reported that helical Vpr13-33 would transform to β-sheet or random coil structures and aggregate on the surface of graphene or graphene oxide through hydrophobic interactions. Due to experimental limitations, however, there is still a considerable lack of understanding on the adsorption dynamics at the early stage of the conformational transition at water-graphene interface and the underlying driving force at molecular level. In this study, atomistic molecular dynamics simulations were used to explore the conformation transition phenomena. Vpr13-33 kept α-helical structure in solution, but changed to β-sheet structure when strongly adsorbed onto graphene. Preferential adsorption of Vpr13-33 on graphene is dominated by hydrophobic interactions. The cluster analysis identified the most significant populated conformation and the early stage of structure conversion from α-helical to β-sheet was found, but the full β-sheet propagation was not observed. Free energy landscape analysis further complemented the transformation analysis of peptide conformations. These findings are consistent with experimental results, and give a molecular level interpretation for the reduced cytotoxicity of Vpr13-33 to some extent upon graphene exposure. Meanwhile, this study provides some significant insights into the detailed mechanism of graphene-induced protein conformation transition.

  8. Structure and function of the regulatory HRDC domain from human Bloom syndrome protein.

    Science.gov (United States)

    Kim, Young Mee; Choi, Byong-Seok

    2010-11-01

    The helicase and RNaseD C-terminal (HRDC) domain, conserved among members of the RecQ helicase family, regulates helicase activity by virtue of variations in its surface residues. The HRDC domain of Bloom syndrome protein (BLM) is known as a critical determinant of the dissolution function of double Holliday junctions by the BLM-Topoisomerase IIIα complex. In this study, we determined the solution structure of the human BLM HRDC domain and characterized its DNA-binding activity. The BLM HRDC domain consists of five α-helices with a hydrophobic 3(10)-helical loop between helices 1 and 2 and an extended acidic surface comprising residues in helices 3-5. The BLM HRDC domain preferentially binds to ssDNA, though with a markedly low binding affinity (K(d) ∼100 μM). NMR chemical shift perturbation studies suggested that the critical DNA-binding residues of the BLM HRDC domain are located in the hydrophobic loop and the N-terminus of helix 2. Interestingly, the isolated BLM HRDC domain had quite different DNA-binding modes between ssDNA and Holliday junctions in electrophoretic mobility shift assay experiments. Based on its surface charge separation and DNA-binding properties, we suggest that the HRDC domain of BLM may be adapted for a unique function among RecQ helicases--that of bridging protein and DNA interactions.

  9. Social dominance-related major urinary proteins and the regulatory mechanism in mice.

    Science.gov (United States)

    Guo, Huifen; Fang, Qi; Huo, Ying; Zhang, Yaohua; Zhang, Jianxu

    2015-11-01

    Major urinary proteins (MUPs) have been proven to be non-volatile male pheromones in mice. Here, we aimed to elucidate the relationship between MUPs and dominance hierarchy, and the underlying molecular mechanisms. Dominance-submission relationship was established by chronic dyadic encountering. We found that at the urinary protein level and hepatic mRNA level, the expression of major MUPs, including Mup20, was enhanced in dominant males compared with subordinate males, indicating that MUPs might signal the social status of male mice. Meanwhile, the mRNA level of hepatic corticotropin releasing hormone receptor 2 (CRHR2) was higher in subordinate male mice than in dominant male mice. Castration also enhanced the expression of CRHR2, but suppressed that of MUPs. CRHR2 agonist treatment reduced the expression of MUPs in liver. However, male social status failed to exert significant influence on serum testosterone and corticosterone as well as the mRNA expression of their receptors. These findings reveal that some MUPs, especially Mup20, might constitute potential dominance pheromones and could be downregulated by hepatic CRHR2, which is possibly independent of androgen or corticosterone systems.

  10. The expression of tumor necrosis factor-alpha, its receptors and steroidogenic acute regulatory protein during corpus luteum regression

    Directory of Open Access Journals (Sweden)

    Arfuso Frank

    2008-11-01

    Full Text Available Abstract Background Corpus luteum (CL regression is known to occur as two parts; functional regression when steroidogenesis declines and structural regression when apoptosis is induced. Previous studies suggest this process occurs by the production of luteolytic factors, such as tumour necrosis factor-alpha (TNF-alpha. Methods We examined TNF-alpha, TNF-alpha receptors (TNFR1 and 2 and steroidogenic acute regulatory (StAR protein expression during CL regression in albino Wistar rats. CL from Days 16 and 22 of pregnancy and Day 3 post-partum were examined, in addition CL from Day 16 of pregnancy were cultured in vitro to induce apoptosis. mRNA was quantitated by kinetic RT-PCR and protein expression examined by immunohistochemistry and Western blot analyses. Results TNF-alpha mRNA increased on Day 3 post-partum. TNFR were immunolocalized to luteal cells, and an increase in TNFR2 mRNA observed on Day 3 post-partum whilst no change was detected in TNFR1 mRNA relative to Day 16. StAR protein decreased on Day 3 post-partum and following trophic withdrawal but no change was observed following exogenous TNF-alpha treatment. StAR mRNA decreased on Day 3 post-partum; however, it increased following trophic withdrawal and TNF-alpha treatment in vitro. Conclusion These results demonstrate the existence of TNFR1 and TNFR2 in rat CL and suggest the involvement of TNF-alpha in rat CL regression following parturition. Furthermore, decreased StAR expression over the same time points was consistent with the functional regression of the CL.

  11. Responsibility of regulatory gene expression and repressed protein synthesis for triacylglycerol accumulation on sulfur-starvation in Chlamydomonas reinhardtii.

    Science.gov (United States)

    Sato, Atsushi; Matsumura, Rie; Hoshino, Naomi; Tsuzuki, Mikio; Sato, Norihiro

    2014-01-01

    Triacylglycerol (TG) synthesis is induced for energy and carbon storage in algal cells under nitrogen(N)-starved conditions, and helps prevent reactive oxygen species (ROS) production through fatty acid synthesis that consumes excessive reducing power. Here, the regulatory mechanism for the TG content in sulfur(S)-starved cells of Chlamydomonas reinhardtii was examined, in comparison to that in N- or phosphorus(P)-starved cells. S- and N- starved cells exhibited markedly increased TG contents with up-regulation of mRNA levels of diacylglycerol acyltransferase (DGAT) genes. S-Starvation also induced expression of the genes for phosphatidate synthesis. In contrast, P-starved cells exhibited little alteration of the TG content with almost no induction of these genes. The results implied deficient nutrient-specific regulation of the TG content. An arg9 disruptant defective in arginine synthesis, even without nutritional deficiencies, exhibited an increased TG content upon removal of supplemented arginine, which repressed protein synthesis. Repression of protein synthesis thus seemed crucial for TG accumulation in S- or N- starved cells. Meanwhile, the results of inhibitor experiments involving cells inferred that TG accumulation during S-starvation is supported by photosynthesis and de novo fatty acid synthesis. During S-starvation, sac1 and snrk2.2 disruptants, which are defective in the response to the ambient S-status, accumulated TG at lower and higher levels, respectively, than the wild type. The sac1 and snrk2.2 disruptants showed no or much greater up-regulation of DGAT genes, respectively. In conclusion, TG synthesis would be activated in S-starved cells, through the diversion of metabolic carbon-flow from protein to TG synthesis, and simultaneously through up-regulation of the expression of a particular set of genes for TG synthesis at proper levels through the actions of SAC1 and SNRK2.2.

  12. Responsibility of regulatory gene expression and repressed protein synthesis for triacylglycerol accumulation on sulfur-starvation in Chlamydomonas reinhardtii

    Directory of Open Access Journals (Sweden)

    Atsushi eSato

    2014-09-01

    Full Text Available Triacylglycerol (TG synthesis is induced for energy and carbon storage in algal cells under nitrogen(N-starved conditions, and helps prevent reactive oxygen species production through fatty acid synthesis that consumes excessive reducing power. Here, the regulatory mechanism for the TG content in sulfur(S-starved cells of Chlamydomonas reinhardtii was examined, in comparison to that in N- or phosphorus(P-starved cells. S- and N-starved cells exhibited markedly increased TG contents with up-regulation of mRNA levels of diacylglycerol acyltransferase genes. S-Starvation also induced expression of the genes for phosphatidate synthesis. In contrast, P-starved cells exhibited little alteration of the TG content with almost no induction of these genes. The results implied deficient nutrient-specific regulation of the TG content. An arg9 disruptant defective in arginine synthesis, even without nutritional deficiencies, exhibited an increased TG content upon removal of supplemented arginine, which repressed protein synthesis. Repression of protein synthesis thus seemed crucial for TG accumulation in S- or N-starved cells. Meanwhile, the results of inhibitor experiments involving cells inferred that TG accumulation during S-starvation is supported by photosynthesis and de novo fatty acid synthesis. During S-starvation, sac1 and snrk2.2 disruptants, which are defective in the response to the ambient S-status, accumulated TG at lower and higher levels, respectively, than the wild type. The sac1 and snrk2.2 disruptants showed no or much greater up-regulation of diacylglycerol acyltransferase genes, respectively. In conclusion, TG synthesis would be activated in S-starved cells, through the diversion of metabolic carbon-flow from protein to TG synthesis, and simultaneously through up-regulation of the expression of a particular set of genes for TG synthesis at proper levels through the actions of SAC1 and SNRK2.2.

  13. The function of the RNA-binding protein TEL1 in moss reveals ancient regulatory mechanisms of shoot development.

    Science.gov (United States)

    Vivancos, Julien; Spinner, Lara; Mazubert, Christelle; Charlot, Florence; Paquet, Nicolas; Thareau, Vincent; Dron, Michel; Nogué, Fabien; Charon, Céline

    2012-03-01

    The shoot represents the basic body plan in land plants. It consists of a repeated structure composed of stems and leaves. Whereas vascular plants generate a shoot in their diploid phase, non-vascular plants such as mosses form a shoot (called the gametophore) in their haploid generation. The evolution of regulatory mechanisms or genetic networks used in the development of these two kinds of shoots is unclear. TERMINAL EAR1-like genes have been involved in diploid shoot development in vascular plants. Here, we show that disruption of PpTEL1 from the moss Physcomitrella patens, causes reduced protonema growth and gametophore initiation, as well as defects in gametophore development. Leafy shoots formed on ΔTEL1 mutants exhibit shorter stems with more leaves per shoot, suggesting an accelerated leaf initiation (shortened plastochron), a phenotype shared with the Poaceae vascular plants TE1 and PLA2/LHD2 mutants. Moreover, the positive correlation between plastochron length and leaf size observed in ΔTEL1 mutants suggests a conserved compensatory mechanism correlating leaf growth and leaf initiation rate that would minimize overall changes in plant biomass. The RNA-binding protein encoded by PpTEL1 contains two N-terminus RNA-recognition motifs, and a third C-terminus non-canonical RRM, specific to TEL proteins. Removal of the PpTEL1 C-terminus (including this third RRM) or only 16-18 amino acids within it seriously impairs PpTEL1 function, suggesting a critical role for this third RRM. These results show a conserved function of the RNA-binding PpTEL1 protein in the regulation of shoot development, from early ancestors to vascular plants, that depends on the third TEL-specific RRM.

  14. The flavone apigenin blocks nuclear translocation of sterol regulatory element-binding protein-2 in the hepatic cells WRL-68.

    Science.gov (United States)

    Wong, Tsz Yan; Lin, Shu-Mei; Leung, Lai K

    2015-06-28

    Sterol regulatory element-binding protein-2 (SREBP-2) is a pivotal transcriptional factor in cholesterol metabolism. Factors interfering with the proper functioning of SREBP-2 potentially alter plasma lipid concentrations. Consuming fruits and vegetables is associated with beneficial plasma lipid profile. The mechanism by which plant foods induce desirable lipid changes remains unclear. Apigenin, a common plant food flavonoid, was shown to modulate the nuclear translocation of SREBP-2 in the hepatic cells WRL-68 in the present study. The processing of SREBP-2 protein occurred after translation, and apigenin blocked this activation route. Further examination indicated that AMP-activated protein kinase (AMPK) was activated by the flavone, and co-administrating the AMPK-specific inhibitor compound C could release the blockage. Reporter gene assay revealed that the transactivation of sterol responsive element (SRE)-containing 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) promoter was suppressed by the flavone. Similarly, electromobility shift assay result also demonstrated a reduced DNA-binding activity on the SRE domain under the same treatment. The reduced transactivity and DNA-binding activity could be attributed to a decreased amount of SREBP-2 translocating from cytosol to nucleus as depicted by confocal microscopy. Quantitative RT-PCR assay demonstrated that the transcription of HMGCR followed the same pattern of SREBP-2 translocation. In summary, the present study showed that apigenin prevented SREBP-2 translocation and reduced the downstream gene HMGCR transcription. The minimum effective dosage should be achievable in the form of functional food consumption or dietary supplementation.

  15. Pancreatic islets engineered with SA-FasL protein establish robust localized tolerance by inducing regulatory T cells in mice.

    Science.gov (United States)

    Yolcu, Esma S; Zhao, Hong; Bandura-Morgan, Laura; Lacelle, Chantale; Woodward, Kyle B; Askenasy, Nadir; Shirwan, Haval

    2011-12-01

    Allogeneic islet transplantation is an important therapeutic approach for the treatment of type 1 diabetes. Clinical application of this approach, however, is severely curtailed by allograft rejection primarily initiated by pathogenic effector T cells regardless of chronic use of immunosuppression. Given the role of Fas-mediated signaling in regulating effector T cell responses, we tested if pancreatic islets can be engineered ex vivo to display on their surface an apoptotic form of Fas ligand protein chimeric with streptavidin (SA-FasL) and whether such engineered islets induce tolerance in allogeneic hosts. Islets were modified with biotin following efficient engineering with SA-FasL protein that persisted on the surface of islets for >1 wk in vitro. SA-FasL-engineered islet grafts established euglycemia in chemically diabetic syngeneic mice indefinitely, demonstrating functionality and lack of acute toxicity. Most importantly, the transplantation of SA-FasL-engineered BALB/c islet grafts in conjunction with a short course of rapamycin treatment resulted in robust localized tolerance in 100% of C57BL/6 recipients. Tolerance was initiated and maintained by CD4(+)CD25(+)Foxp3(+) regulatory T (Treg) cells, as their depletion early during tolerance induction or late after established tolerance resulted in prompt graft rejection. Furthermore, Treg cells sorted from graft-draining lymph nodes, but not spleen, of long-term graft recipients prevented the rejection of unmodified allogeneic islets in an adoptive transfer model, further confirming the Treg role in established tolerance. Engineering islets ex vivo in a rapid and efficient manner to display on their surface immunomodulatory proteins represents a novel, safe, and clinically applicable approach with important implications for the treatment of type 1 diabetes.

  16. Pancreatic Islets Engineered with SA-FasL Protein Establish Robust Localized Tolerance by Inducing T Regulatory Cells in Mice

    Science.gov (United States)

    Yolcu, Esma S; Zhao, Hong; Bandura-Morgan, Laura; Lacelle, Chantale; Woodward, Kyle B; Askenasy, Nadir; Shirwan, Haval

    2011-01-01

    Allogeneic islet transplantation is an important therapeutic approach for the treatment of T1D. Clinical application of this approach, however, is severely curtailed by allograft rejection primarily initiated by pathogenic T effector cells regardless of chronic use of immunosuppression. Given the role of Fas-mediated signaling in regulating T effector cell responses, we tested if pancreatic islets can be engineered ex vivo to display on their surface an apoptotic form of FasL protein chimeric with streptavidin (SA-FasL), and whether such engineered islets induce tolerance in allogeneic hosts. Islets were modified with biotin following efficient engineering with SA-FasL protein that persisted on the surface of islets for over a week in vitro. SA-FasL-engineered islet grafts established euglycemia in chemically diabetic syngeneic mice indefinitely, demonstrating functionality and lack of acute toxicity. Most importantly, the transplantation of SA-FasL-engineered BALB/c islet grafts in conjunction with a short course of rapamycin treatment resulted in robust localized tolerance in 100% C57BL/6 recipients. Tolerance was initiated and maintained by CD4+CD25+FoxP3+ T regulatory (Treg) cells as their depletion early during tolerance induction or late after established tolerance resulted in prompt graft rejection. Furthermore, Treg cells sorted from graft-draining lymph nodes, but not spleen, of long-term graft recipients prevented the rejection of unmodified allogeneic islets in an adoptive transfer model, further confirming the Treg role in established tolerance. Engineering islets ex vivo in a rapid and efficient manner to display on their surface immunomodulatory proteins represents a novel, safe, and clinically applicable approach with important implications for the treatment of T1D. PMID:22068235

  17. Regulatory roles of tumor necrosis factor alpha-induced proteins (TNFAIPs) 3 and 9 in arthritis.

    Science.gov (United States)

    Matsumoto, Isao; Inoue, Asuka; Takai, Chinatsu; Umeda, Naoto; Tanaka, Yuki; Kurashima, Yuko; Sumida, Takayuki

    2014-07-01

    Tumor necrosis factor alpha (TNFα) and interleukin-6 (IL-6) have proved to be important in rheumatoid arthritis (RA) because the outcome of RA has greatly improved with the recent availability of biologics targeting them. It is well accepted that these cytokines are involved in the activation of the nuclear factor-κB (NF-κB) signaling pathway, but our understanding of the dependency of these pro-inflammatory cytokines and the link between them in RA is currently limited. Recently, we and others proved the importance of TNFα-induced protein (TNFAIP), due to the spontaneous development of arthritis in deficient animals that are dependent on IL-6. To date, nine TNFAIPs have been identified, and TNFAIP3 and TNFAIP9 were found to be clearly associated with mouse and human arthritis. In this review, we compare and discuss recent TNFAIP topics, especially focusing on TNFAIP3 and TNFAIP9 in autoimmune arthritis in mice and humans.

  18. Identification of a Novel Transcript and Regulatory Mechanism for Microsomal Triglyceride Transfer Protein

    Science.gov (United States)

    Suzuki, Takashi; Brown, Judy J.; Swift, Larry L.

    2016-01-01

    Microsomal triglyceride transfer protein (MTP) is essential for the assembly of triglyceride-rich apolipoprotein B-containing lipoproteins. Previous studies in our laboratory identified a novel splice variant of MTP in mice that we named MTP-B. MTP-B has a unique first exon (1B) located 2.7 kB upstream of the first exon (1A) for canonical MTP (MTP-A). The two mature isoforms, though nearly identical in sequence and function, have different tissue expression patterns. In this study we report the identification of a second MTP splice variant (MTP-C), which contains both exons 1B and 1A. MTP-C is expressed in all the tissues we tested. In cells transfected with MTP-C, protein expression was less than 15% of that found when the cells were transfected with MTP-A or MTP-B. In silico analysis of the 5’-UTR of MTP-C revealed seven ATGs upstream of the start site for MTP-A, which is the only viable start site in frame with the main coding sequence. One of those ATGs was located in the 5’-UTR for MTP-A. We generated reporter constructs in which the 5’-UTRs of MTP-A or MTP-C were inserted between an SV40 promoter and the coding sequence of the luciferase gene and transfected these constructs into HEK 293 cells. Luciferase activity was significantly reduced by the MTP-C 5’-UTR, but not by the MTP-A 5’-UTR. We conclude that alternative splicing plays a key role in regulating MTP expression by introducing unique 5’-UTRs, which contain elements that alter translation efficiency, enabling the cell to optimize MTP levels and activity. PMID:26771188

  19. Adaptive and maladaptive expression of the mRNA regulatory protein HuR

    Institute of Scientific and Technical Information of China (English)

    Suman; Govindaraju; Beth; S; Lee

    2013-01-01

    The RNA-binding proteins involved in regulation of mRNA post-transcriptional processing and translation control the fates of thousands of mRNA transcripts and basic cellular processes. The best studied of these, HuR, is well characterized as a mediator of mRNA stability and translation, and more recently, as a factor in nuclear functions such as pre-mRNA splicing. Due to HuR’s role in regulating thousands of mRNA transcripts, including those for other RNA-binding proteins, HuR can act as a master regulator of cell survival and proliferation. HuR itself is subject to multiple post-translationa modifications including regulation of its nucleocytoplasmic distribution. However, the mechanisms that govern HuR levels in the cell have only recently begun to be defined. These mechanisms are critical to cell health, as it has become clear in recent years that aberrant expression of HuR can lead alternately to decreased cell viability or to promotion of pathological proliferation and invasiveness. HuR is expressed as alternate mRNAs that vary in their untranslated regions, leading to differences in transcript stability and translatability. Multiple transcription factors and modulators of mRNA stability that regulate HuR mRNA expression have been identified. In addition, translation of HuR is regulated by numerous microRNAs, several of which have been demonstrated to have anti-tumor properties due to their suppression of HuR expression. This review summarizes the current state of knowledge of the factors that regulate HuR expression, along with the circumstances under which these factors contribute to cancer and inflammation.

  20. Exercise promotes BCAA catabolism: effects of BCAA supplementation on skeletal muscle during exercise.

    Science.gov (United States)

    Shimomura, Yoshiharu; Murakami, Taro; Nakai, Naoya; Nagasaki, Masaru; Harris, Robert A

    2004-06-01

    Branched-chain amino acids (BCAAs) are essential amino acids that can be oxidized in skeletal muscle. It is known that BCAA oxidation is promoted by exercise. The mechanism responsible for this phenomenon is attributed to activation of the branched-chain alpha-keto acid dehydrogenase (BCKDH) complex, which catalyzes the second-step reaction of the BCAA catabolic pathway and is the rate-limiting enzyme in the pathway. This enzyme complex is regulated by a phosphorylation-dephosphorylation cycle. The BCKDH kinase is responsible for inactivation of the complex by phosphorylation, and the activity of the kinase is inversely correlated with the activity state of the BCKDH complex, which suggests that the kinase is the primary regulator of the complex. We found recently that administration of ligands for peroxisome proliferator-activated receptor-alpha (PPARalpha) in rats caused activation of the hepatic BCKDH complex in association with a decrease in the kinase activity, which suggests that promotion of fatty acid oxidation upregulates the BCAA catabolism. Long-chain fatty acids are ligands for PPARalpha, and the fatty acid oxidation is promoted by several physiological conditions including exercise. These findings suggest that fatty acids may be one of the regulators of BCAA catabolism and that the BCAA requirement is increased by exercise. Furthermore, BCAA supplementation before and after exercise has beneficial effects for decreasing exercise-induced muscle damage and promoting muscle-protein synthesis; this suggests the possibility that BCAAs are a useful supplement in relation to exercise and sports.

  1. Adaptation of phenylalanine and tyrosine catabolic pathway to hibernation in bats.

    Directory of Open Access Journals (Sweden)

    Yi-Hsuan Pan

    Full Text Available Some mammals hibernate in response to harsh environments. Although hibernating mammals may metabolize proteins, the nitrogen metabolic pathways commonly activated during hibernation are not fully characterized. In contrast to the hypothesis of amino acid preservation, we found evidence of amino acid metabolism as three of five key enzymes, including phenylalanine hydroxylase (PAH, homogentisate 1,2-dioxygenase (HGD, fumarylacetoacetase (FAH, involved in phenylalanine and tyrosine catabolism were co-upregulated during hibernation in two distantly related species of bats, Myotis ricketti and Rhinolophus ferrumequinum. In addition, the levels of phenylalanine in the livers of these bats were significantly decreased during hibernation. Because phenylalanine and tyrosine are both glucogenic and ketogenic, these results indicate the role of this catabolic pathway in energy supply. Since any deficiency in the catabolism of these two amino acids can cause accumulations of toxic metabolites, these results also suggest the detoxification role of these enzymes during hibernation. A higher selective constraint on PAH, HPD, and HGD in hibernators than in non-hibernators was observed, and hibernators had more conserved amino acid residues in each of these enzymes than non-hibernators. These conserved amino acid residues are mostly located in positions critical for the structure and activity of the enzymes. Taken together, results of this work provide novel insights in nitrogen metabolism and removal of harmful metabolites during bat hibernation.

  2. Sesamin inhibits lipopolysaccharide-induced inflammation and extracellular matrix catabolism in rat intervertebral disc.

    Science.gov (United States)

    Li, Kang; Li, Yan; Xu, Bo; Mao, Lu; Zhao, Jie

    2016-09-01

    Intervertebral disc (IVD) degeneration contributes to most spinal degenerative diseases, while treatment inhibiting IVD degeneration is still in the experimental stage. Sesamin, a bioactive component extracted from sesame, has been reported to exert chondroprotective and anti-inflammatory effects. Here, we analyzed the anti-inflammatory and anti-catabolic effects of sesamin on rat IVD in vitro and ex vivo. Results show that sesamin significantly inhibits the lipopolysaccharide (LPS)-induced expression of catabolic enzymes (MMP-1, MMP-3, MMP-13, ADAMTS-4, ADAMTS-5) and inflammation factors (IL-1β, TNF-α, iNOS, NO, COX-2, PGE2) in a dose-dependent manner in vitro. It is also proven that migration of macrophages induced by LPS can be inhibited by treatment with sesamin. Organ culture experiments demonstrate that sesamin protects the IVD from LPS-induced depletion of the extracellular matrix ex vivo. Moreover, sesamin suppresses LPS-induced activation of the mitogen-activated protein kinase (MAPK) pathway through inhibiting phosphorylation of JNK, the common downstream signaling pathway of LPS and IL-1β, which may be the potential mechanism of the effects of sesamin. In light of our results, sesamin protects the IVD from inflammation and extracellular matrix catabolism, presenting positive prospects in the treatment of IVD degenerative diseases.

  3. Adaptation of phenylalanine and tyrosine catabolic pathway to hibernation in bats.

    Science.gov (United States)

    Pan, Yi-Hsuan; Zhang, Yijian; Cui, Jie; Liu, Yang; McAllan, Bronwyn M; Liao, Chen-Chung; Zhang, Shuyi

    2013-01-01

    Some mammals hibernate in response to harsh environments. Although hibernating mammals may metabolize proteins, the nitrogen metabolic pathways commonly activated during hibernation are not fully characterized. In contrast to the hypothesis of amino acid preservation, we found evidence of amino acid metabolism as three of five key enzymes, including phenylalanine hydroxylase (PAH), homogentisate 1,2-dioxygenase (HGD), fumarylacetoacetase (FAH), involved in phenylalanine and tyrosine catabolism were co-upregulated during hibernation in two distantly related species of bats, Myotis ricketti and Rhinolophus ferrumequinum. In addition, the levels of phenylalanine in the livers of these bats were significantly decreased during hibernation. Because phenylalanine and tyrosine are both glucogenic and ketogenic, these results indicate the role of this catabolic pathway in energy supply. Since any deficiency in the catabolism of these two amino acids can cause accumulations of toxic metabolites, these results also suggest the detoxification role of these enzymes during hibernation. A higher selective constraint on PAH, HPD, and HGD in hibernators than in non-hibernators was observed, and hibernators had more conserved amino acid residues in each of these enzymes than non-hibernators. These conserved amino acid residues are mostly located in positions critical for the structure and activity of the enzymes. Taken together, results of this work provide novel insights in nitrogen metabolism and removal of harmful metabolites during bat hibernation.

  4. Effects of simvastatin on cardiac performance and expression of sarcoplasmic reticular calcium regulatory proteins in rat heart

    Institute of Scientific and Technical Information of China (English)

    Xia ZHENG; Shen-jiang HU

    2005-01-01

    Aim: To investigate the effect of simvastatin on the cardiac contractile function and the alteration of gene and protein expression of the sarcoplasmic calcium regulatory proteins, including sarcoplasmic reticulum Ca2+-ATPase (SERCA),phospholamban (PLB), and ryanodine receptor 2 (RyR2) in rat hearts. Methods:Langendorff-perfused rat hearts were subjected to 60-min perfusion with different concentrations of simvastatin (1, 3, 10, 30, or 100 μmol/L), and the parameters of cardiac function such as left ventricular developed pressure (LVDP), +dp/dtmax,and -dp/dtmax were determined. The cultured neonatal rat ventricular cardiomyocytes were incubated with simvastatin (1, 3, 10, 30, and 100 μmol/L) for 1 h or 24 h.The levels of SERCA, PLB, and RyR2 expression were measured by reverse transcription-polymerase chain reaction and Western blot. Cytotoxic effect of simvastatin on ventricular cardiomyocytes was assessed by the MTT colorimetric assay.Results: LVDP, +dp/dtmax, and -dp/dtmax of hearts were increased significantly after treatment with simvastatin 3, 10, and 30 μmol/L. In simvastatin-treated isolated hearts, the levels of mRNA expression of SERCA and RyR2 were elevated compared with the control (P<0.05), while the mRNA expression of PLB did not change. After the cultured neonatal rat ventricular cardiomyocytes were incubated with 3, 10, 30, and 100 μmol/L simvastatin for 1 h, SERCA and RyR2 mRNA expressions of cardiomyocytes rose, but there was no alteration in protein expressions. However, with the elongation of simvastatin treatment to 24 h, the protein expression of SERCA and RyR2 were also elevated. Additionally,simvastatin (1-30 μmol/L) had no influence on cell viability of cultured cardiac myocytes, but simvastatin 100 μmol/L inhibited the cell viability. Conclusion:Simvastatin improved cardiac performance accompanied by the elevation of SERCA and RyR2 gene and protein expression.

  5. Molecular dynamics simulations of conformation changes of HIV-1 regulatory protein on graphene

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Daohui; Li, Libo; He, Daohang; Zhou, Jian, E-mail: jianzhou@scut.edu.cn

    2016-07-30

    Graphical abstract: Preferential adsorption of Vpr13-33 on graphene accompanied by early conformational change from α-helix to β-sheet structures was observed by molecular simulations. This work presents the molecular mechanism of graphene-induced peptide conformational alteration and sheds light on developing graphene-based materials to inhibit HIV. - Highlights: • Graphene induced early structural transition of Vpr13-33 is studied by MD simulations. • Both π-π stacking and hydrophobic interactions orchestrate the peptide adsorption. • Vpr has an increased propensity of β-sheet content on graphene surface. • To develop graphene-based materials to inhibit HIV is possible. - Abstract: The fragment of viral protein R (Vpr), Vpr13-33, plays an important role in regulating nuclear importing of HIV genes through channel formation in which it adopts a leucine-zipper-like alpha-helical conformation. A recent experimental study reported that helical Vpr13-33 would transform to β-sheet or random coil structures and aggregate on the surface of graphene or graphene oxide through hydrophobic interactions. Due to experimental limitations, however, there is still a considerable lack of understanding on the adsorption dynamics at the early stage of the conformational transition at water-graphene interface and the underlying driving force at molecular level. In this study, atomistic molecular dynamics simulations were used to explore the conformation transition phenomena. Vpr13-33 kept α-helical structure in solution, but changed to β-sheet structure when strongly adsorbed onto graphene. Preferential adsorption of Vpr13-33 on graphene is dominated by hydrophobic interactions. The cluster analysis identified the most significant populated conformation and the early stage of structure conversion from α-helical to β-sheet was found, but the full β-sheet propagation was not observed. Free energy landscape analysis further complemented the transformation analysis of

  6. Evidence that regulatory protein MarA of Escherichia coli represses rob by steric hindrance.

    Science.gov (United States)

    McMurry, Laura M; Levy, Stuart B

    2010-08-01

    The MarA protein of Escherichia coli can both activate and repress the initiation of transcription, depending on the position and orientation of its degenerate 20-bp binding site ("marbox") at the promoter. For all three known repressed genes, the marbox overlaps the promoter. It has been reported that MarA represses the rob promoter via an RNA polymerase (RNAP)-DNA-MarA ternary complex. Under similar conditions, we found a ternary complex for the repressed purA promoter also. These findings, together with the backwards orientation of repressed marboxes, suggested a unique interaction of MarA with RNAP in repression. However, no repression-specific residues of MarA could be found among 38 single-alanine replacement mutations previously shown to retain activation function or among mutants from random mutagenesis. Mutations Thr12Ala, Arg36Ala, Thr95Ile, and Pro106Ala were more damaging for activation than for repression, some up to 10-fold, so these residues may play a specific role in activation. We found that nonspecific binding of RNAP to promoterless regions of DNA was presumably responsible for the ternary complexes seen previously. When RNAP binding was promoter specific, MarA reduced RNAP access to the rob promoter; there was little or no ternary complex. These findings strongly implicate steric hindrance as the mechanism of repression of rob by MarA.

  7. Regulatory roles of tumor-suppressor proteins and noncoding RNA in cancer and normal cell functions.

    Science.gov (United States)

    Garen, Alan; Song, Xu

    2008-04-15

    We describe a mechanism for reversible regulation of gene transcription, mediated by a family of tumor-suppressor proteins (TSP) containing a DNA-binding domain (DBD) that binds to a gene and represses transcription, and RNA-binding domains (RBDs) that bind RNA, usually a noncoding RNA (ncRNA), forming a TSP/RNA complex that releases the TSP from a gene and reverses repression. This mechanism appears to be involved in the regulation of embryogenesis, oncogenesis, and steroidogenesis. Embryonic cells express high levels of RNA that bind to a TSP and prevent repression of proto-oncogenes that drive cell proliferation. The level of the RNA subsequently decreases in most differentiating cells, enabling a TSP to repress proto-oncogenes and stop cell proliferation. Oncogenesis can result when the level of the RNA fails to decrease in a proliferating cell or increases in a differentiated cell. This mechanism also regulates transcription of P450scc, the first gene in the steroidogenic pathway.

  8. Effects of human growth hormone on the catabolic state after surgical trauma.

    Science.gov (United States)

    Vara-Thorbeck, R; Ruiz-Requena, E; Guerrero-Fernández, J A

    1996-01-01

    The aims of our studies were: (1) to determine if the protein catabolic response after a major or moderate surgical trauma can be restrained by the administration of exogenous human growth hormone (hGH); (2) to determine if the administration of hGH can improve systemic host defenses, thus reducing the risk of infection, and (3) given that the postoperative fatigue syndrome (POF) is mediated by the endocrino-metabolic response to surgery we attempt to determine if the administration of hGH can prevent or reduce POF. Therefore, we performed three placebo-controlled randomized double-blind trials on 216 patients. Major gastrointestinal surgery was treated only with total parenteral nutrition (TPN; n = 20) or TPN plus 4 IU hGH (n = 18). Patients with moderate surgical trauma received either hypocaloric parenteral nutrition (HPN; n = 93) or HPN and 8 IU hGH (n = 87). In this study, we also determined the evolution of the systemic host defenses and thereby the risk of infection. In 48 patients who underwent cholecystectomy treated (n = 26) either with HPN or HPN plus 8 IU hGH, we measured the protein catabolic response, postoperative fatigue and anthropometric modifications. The treatment with hGH together with HPN or TPN (1) overcomes the protein catabolic effects of the trauma response induced by major or moderate surgery by increasing protein synthesis, (2) improves humoral and cellular systemic host defenses, thus reducing the risk of infection, (3) preserves or increases lean body mass and reduces adipose tissue and (4) minimizes POF.

  9. MAR binding protein SMAR1 favors IL-10 mediated regulatory T cell function in acute colitis

    Energy Technology Data Exchange (ETDEWEB)

    Mirlekar, Bhalchandra; Patil, Sachin [Chromatin and Disease Biology Laboratory, National Centre for Cell Science, Ganeshkhind, Pune 411007 (India); Bopanna, Ramanamurthy [Experimental Animal Facility, National Centre for Cell Science, Ganeshkhind, Pune 411007 (India); Chattopadhyay, Samit, E-mail: samit@nccs.res.in [Chromatin and Disease Biology Laboratory, National Centre for Cell Science, Ganeshkhind, Pune 411007 (India)

    2015-08-21

    T{sub reg} cells are not only crucial for controlling immune responses to autoantigens but also prevent those directed towards commensal pathogens. Control of effector immune responses by T{sub reg} cells depend on their capacity to accumulate at inflammatory site and accordingly accommodate to inflammatory environment. Till date, the factors associated with maintaining these aspects of T{sub reg} phenotype is not understood properly. Here we have shown that a known nuclear matrix binding protein SMAR1 is selectively expressed more in colonic T{sub reg} cells and is required for their ability to accumulate at inflammatory site and to sustain high levels of Foxp3 and IL-10 expression during acute colitis. Elimination of anti-inflammatory subsets revealed a protective role for IL-10 producing T{sub reg} cells in SMAR1{sup −/−} mice. Moreover, a combined action of Foxp3 and SMAR1 restricts effector cytokine production and enhance the production of IL-10 by colonic T{sub reg} cells that controls acute colitis. This data highlights a critical role of SMAR1 in maintaining T{sub reg} physiology during inflammatory disorders. - Highlights: • SMAR1 is essential to sustain high level of Foxp3 and IL-10 in T{sub reg} cells. • SMAR1{sup −/−} T{sub reg} cells produce pro-inflammatory cytokine IL-17 leads to inflammation. • IL-10 administration can control the inflammation in SMAR1{sup −/−} mice. • Both Foxp3 and SMAR1 maintain T{sub reg} phenotype that controls colitis.

  10. Hepatitis C virus nonstructural protein-5A activates sterol regulatory element-binding protein-1c through transcription factor Sp1

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Zhonghua; Qiao, Ling; Zhou, Yan [Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E3 (Canada); Babiuk, Lorne A. [University of Alberta, Edmonton, Alberta (Canada); Liu, Qiang, E-mail: qiang.liu@usask.ca [Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E3 (Canada)

    2010-11-19

    Research highlights: {yields} A chimeric subgenomic HCV replicon expresses HCV-3a NS5A in an HCV-1b backbone. {yields} HCV-3a NS5A increases mature SREBP-1c protein level. {yields} HCV-3a NS5A activates SREBP-1c transcription. {yields} Domain II of HCV-3a NS5A is more effective in SREBP-1c promoter activation. {yields} Transcription factor Sp1 is required for SREBP-1c activation by HCV-3a NS5A. -- Abstract: Steatosis is an important clinical manifestation of hepatitis C virus (HCV) infection. The molecular mechanisms of HCV-associated steatosis are not well understood. Sterol regulatory element-binding protein-1c (SREBP-1c) is a key transcription factor which activates the transcription of lipogenic genes. Here we showed that the nuclear, mature SREBP-1c level increases in the nucleus of replicon cells expressing HCV-3a nonstructural protein-5A (NS5A). We further showed that HCV-3a NS5A up-regulates SREBP-1c transcription. Additional analysis showed that transcriptional factor Sp1 is involved in SREBP-1c activation by HCV-3a NS5A because inhibition of Sp1 activity by mithramycin A or a dominant-negative Sp1 construct abrogated SREBP-1c promoter activation by HCV-3a NS5A. In addition, chromatin immunoprecipitation (ChIP) assay demonstrated enhanced binding of Sp1 on the SREBP-1c promoter in HCV-3a NS5A replicon cells. These results showed that HCV-3a NS5A activates SREBP-1c transcription through Sp1. Taken together, our results suggest that HCV-3a NS5A is a contributing factor for steatosis caused by HCV-3a infection.

  11. A Model of Yeast Cell-Cycle Regulation Based on a Standard Component Modeling Strategy for Protein Regulatory Networks

    Science.gov (United States)

    Laomettachit, Teeraphan; Chen, Katherine C.; Baumann, William T.

    2016-01-01

    To understand the molecular mechanisms that regulate cell cycle progression in eukaryotes, a variety of mathematical modeling approaches have been employed, ranging from Boolean networks and differential equations to stochastic simulations. Each approach has its own characteristic strengths and weaknesses. In this paper, we propose a “standard component” modeling strategy that combines advantageous features of Boolean networks, differential equations and stochastic simulations in a framework that acknowledges the typical sorts of reactions found in protein regulatory networks. Applying this strategy to a comprehensive mechanism of the budding yeast cell cycle, we illustrate the potential value of standard component modeling. The deterministic version of our model reproduces the phenotypic properties of wild-type cells and of 125 mutant strains. The stochastic version of our model reproduces the cell-to-cell variability of wild-type cells and the partial viability of the CLB2-dbΔ clb5Δ mutant strain. Our simulations show that mathematical modeling with “standard components” can capture in quantitative detail many essential properties of cell cycle control in budding yeast. PMID:27187804

  12. Association of pro-inflammatory cytokines and iron regulatory protein 2 (IRP2 with Leishmania burden in canine visceral leishmaniasis.

    Directory of Open Access Journals (Sweden)

    Paulo Ricardo Porfírio do Nascimento

    Full Text Available Leishmania infantum infection in humans and dogs can evolve with a wide range of clinical presentations, varying from asymptomatic infections to visceral leishmaniasis. We hypothesized that the immune response elicited by L. infantum infection could modulate whether the host will remain asymptomatic or progress to disease. A total of 44 dogs naturally infected with L. infantum were studied. Leishmania burden was estimated in the blood and spleen by qPCR. The expression of IFN-γ, TNF-α, IL-10 and Iron Regulatory Protein 2 (IRP2 were determined in the spleen by quantitative PCR. Sera cytokines were evaluated by ELISA. Dogs were grouped in quartiles according parasite burden. Increased expression of IFN-γ and TNF-α was associated with reduced Leishmania burden, whereas increased IL-10 and IRP2 expressions were associated with higher Leishmania load. Increased plasma albumin and IFN-γ expression explained 22.8% of the decrease in parasite burden in the spleen. These data confirm that lower IFN-γ response and higher IL-10 correlated with increased parasite load and severity of the visceral leishmaniasis in dogs. The balance between the branches of immune response and the intracellular iron availability could determine, in part, the course of Leishmania infection.

  13. Characterization of novel StAR (steroidogenic acute regulatory protein mutations causing non-classic lipoid adrenal hyperplasia.

    Directory of Open Access Journals (Sweden)

    Christa E Flück

    Full Text Available CONTEXT: Steroidogenic acute regulatory protein (StAR is crucial for transport of cholesterol to mitochondria where biosynthesis of steroids is initiated. Loss of StAR function causes lipoid congenital adrenal hyperplasia (LCAH. OBJECTIVE: StAR gene mutations causing partial loss of function manifest atypical and may be mistaken as familial glucocorticoid deficiency. Only a few mutations have been reported. DESIGN: To report clinical, biochemical, genetic, protein structure and functional data on two novel StAR mutations, and to compare them with published literature. SETTING: Collaboration between the University Children's Hospital Bern, Switzerland, and the CIBERER, Hospital Vall d'Hebron, Autonomous University, Barcelona, Spain. PATIENTS: Two subjects of a non-consanguineous Caucasian family were studied. The 46,XX phenotypic normal female was diagnosed with adrenal insufficiency at the age of 10 months, had normal pubertal development and still has no signs of hypergonodatropic hypogonadism at 32 years of age. Her 46,XY brother was born with normal male external genitalia and was diagnosed with adrenal insufficiency at 14 months. Puberty was normal and no signs of hypergonadotropic hypogonadism are present at 29 years of age. RESULTS: StAR gene analysis revealed two novel compound heterozygote mutations T44HfsX3 and G221S. T44HfsX3 is a loss-of-function StAR mutation. G221S retains partial activity (∼30% and is therefore responsible for a milder, non-classic phenotype. G221S is located in the cholesterol binding pocket and seems to alter binding/release of cholesterol. CONCLUSIONS: StAR mutations located in the cholesterol binding pocket (V187M, R188C, R192C, G221D/S seem to cause non-classic lipoid CAH. Accuracy of genotype-phenotype prediction by in vitro testing may vary with the assays employed.

  14. Regulation of the CDP-choline pathway by sterol regulatory element binding proteins involves transcriptional and post-transcriptional mechanisms.

    Science.gov (United States)

    Ridgway, Neale D; Lagace, Thomas A

    2003-06-15

    The synthesis of phosphatidylcholine (PtdCho) by the CDP-choline pathway is under the control of the rate-limiting enzyme CTP:phosphocholine cytidylyltransferase (CCT). Sterol regulatory element binding proteins (SREBPs) have been proposed to regulate CCT at the transcriptional level, or via the synthesis of lipid activators or substrates of the CDP-choline pathway. To assess the contributions of these two mechanisms, we examined CCTalpha expression and PtdCho synthesis by the CDP-choline pathway in cholesterol and fatty acid auxotrophic CHO M19 cells inducibly expressing constitutively active nuclear forms of SREBP1a or SREBP2. Induction of either SREBP resulted in increased expression of mRNAs for sterol-regulated genes, elevated fatty acid and cholesterol synthesis (>10-50-fold) and increased PtdCho synthesis (2-fold). CCTalpha mRNA was increased 2-fold by enforced expression of SREBP1a or SREBP2. The resultant increase in CCTalpha protein and activity (2-fold) was restricted primarily to the soluble fraction of cells, and increased CCTalpha activity in vivo was not detected. Inhibition of the synthesis of fatty acids or their CoA esters by cerulenin or triacsin C respectively following SREBP induction effectively blocked the accompanying elevation in PtdCho synthesis. Thus PtdCho synthesis was driven by increased synthesis of fatty acids or a product thereof. These data show that transcriptional activation of CCTalpha is modest relative to that of other SREBP-regulated genes, and that stimulation of PtdCho synthesis by SREBPs in CHO cells is due primarily to increased fatty acid synthesis.

  15. Small-molecule inhibition of choline catabolism in Pseudomonas aeruginosa and other aerobic choline-catabolizing bacteria.

    Science.gov (United States)

    Fitzsimmons, Liam F; Flemer, Stevenson; Wurthmann, A Sandy; Deker, P Bruce; Sarkar, Indra Neil; Wargo, Matthew J

    2011-07-01

    Choline is abundant in association with eukaryotes and plays roles in osmoprotection, thermoprotection, and membrane biosynthesis in many bacteria. Aerobic catabolism of choline is widespread among soil proteobacteria, particularly those associated with eukaryotes. Catabolism of choline as a carbon, nitrogen, and/or energy source may play important roles in association with eukaryotes, including pathogenesis, symbioses, and nutrient cycling. We sought to generate choline analogues to study bacterial choline catabolism in vitro and in situ. Here we report the characterization of a choline analogue, propargylcholine, which inhibits choline catabolism at the level of Dgc enzyme-catalyzed dimethylglycine demethylation in Pseudomonas aeruginosa. We used genetic analyses and 13C nuclear magnetic resonance to demonstrate that propargylcholine is catabolized to its inhibitory form, propargylmethylglycine. Chemically synthesized propargylmethylglycine was also an inhibitor of growth on choline. Bioinformatic analysis suggests that there are genes encoding DgcA homologues in a variety of proteobacteria. We examined the broader utility of propargylcholine and propargylmethylglycine by assessing growth of other members of the proteobacteria that are known to grow on choline and possess putative DgcA homologues. Propargylcholine showed utility as a growth inhibitor in P. aeruginosa but did not inhibit growth in other proteobacteria tested. In contrast, propargylmethylglycine was able to inhibit choline-dependent growth in all tested proteobacteria, including Pseudomonas mendocina, Pseudomonas fluorescens, Pseudomonas putida, Burkholderia cepacia, Burkholderia ambifaria, and Sinorhizobium meliloti. We predict that chemical inhibitors of choline catabolism will be useful for studying this pathway in clinical and environmental isolates and could be a useful tool to study proteobacterial choline catabolism in situ.

  16. Polyamine catabolism in carcinogenesis: potential targets for chemotherapy and chemoprevention.

    Science.gov (United States)

    Battaglia, Valentina; DeStefano Shields, Christina; Murray-Stewart, Tracy; Casero, Robert A

    2014-03-01

    Polyamines, including spermine, spermidine, and the precursor diamine, putrescine, are naturally occurring polycationic alkylamines that are required for eukaryotic cell growth, differentiation, and survival. This absolute requirement for polyamines and the need to maintain intracellular levels within specific ranges require a highly regulated metabolic pathway primed for rapid changes in response to cellular growth signals, environmental changes, and stress. Although the polyamine metabolic pathway is strictly regulated in normal cells, dysregulation of polyamine metabolism is a frequent event in cancer. Recent studies suggest that the polyamine catabolic pathway may be involved in the etiology of some epithelial cancers. The catabolism of spermine to spermidine utilizes either the one-step enzymatic reaction of spermine oxidase (SMO) or the two-step process of spermidine/spermine N (1)-acetyltransferase (SSAT) coupled with the peroxisomal enzyme N (1)-acetylpolyamine oxidase. Both catabolic pathways produce hydrogen peroxide and a reactive aldehyde that are capable of damaging DNA and other critical cellular components. The catabolic pathway also depletes the intracellular concentrations of spermidine and spermine, which are free radical scavengers. Consequently, the polyamine catabolic pathway in general and specifically SMO and SSAT provide exciting new targets for chemoprevention and/or chemotherapy.

  17. Glibenclamide Induces Collagen IV Catabolism in High Glucose-Stimulated Mesangial Cells

    Directory of Open Access Journals (Sweden)

    Liping Zhu

    2012-01-01

    Full Text Available We have shown the full prevention of mesangial expansion in insulin-deficient diabetic rats by treatment with clinically-relevant dosages of glibenclamide (Glib. Studies in mesangial cells (MCs also demonstrated reduction in the high glucose (HG-induced accumulation of collagens, proposing that this was due to increased catabolism. In the present study, we investigated the signaling pathways that may be implicated in Glib action. Rat primary MCs were exposed to HG for 8 weeks with or without Glib in therapeutic (0.01 μM or supratherapeutic (1.0 μM concentrations. We found that HG increased collagen IV protein accumulation and PAI-1 mRNA and protein expression, in association with decreased cAMP generating capacity and decreased PKA activity. Low Glib increased collagen IV mRNA but fully prevented collagen IV protein accumulation and PAI-1 overexpression while enhancing cAMP formation and PKA activity. MMP2 mRNA, protein expression and gelatinolytic activity were also enhanced. High Glib was, overall, ineffective. In conclusion, low dosage/concentration Glib prevents HG-induced collagen accumulation in MC by enhancing collagen catabolism in a cAMP-PKA-mediated PAI-1 inhibition.

  18. Specific and Quantitative Assessment of Naphthalene and Salicylate Bioavailability by Using a Bioluminescent Catabolic Reporter Bacterium

    Science.gov (United States)

    Heitzer, Armin; Webb, Oren F.; Thonnard, Janeen E.; Sayler, Gary S.

    1992-01-01

    A bioassay was developed and standardized for the rapid, specific, and quantitative assessment of naphthalene and salicylate bioavailability by use of bioluminescence monitoring of catabolic gene expression. The bioluminescent reporter strain Pseudomonas fluorescens HK44, which carries a transcriptional nahG-luxCDABE fusion for naphthalene and salicylate catabolism, was used. The physiological state of the reporter cultures as well as the intrinsic regulatory properties of the naphthalene degradation operon must be taken into account to obtain a high specificity at low target substrate concentrations. Experiments have shown that the use of exponentially growing reporter cultures has advantages over the use of carbon-starved, resting cultures. In aqueous solutions for both substrates, naphthalene and salicylate, linear relationships between initial substrate concentration and bioluminescence response were found over concentration ranges of 1 to 2 orders of magnitude. Naphthalene could be detected at a concentration of 45 ppb. Studies conducted under defined conditions with extracts and slurries of experimentally contaminated sterile soils and identical uncontaminated soil controls demonstrated that this method can be used for specific and quantitative estimations of target pollutant presence and bioavailability in soil extracts and for specific and qualitative estimations of napthalene in soil slurries. PMID:16348717

  19. Properties of the phage-shock-protein (Psp) regulatory complex that govern signal transduction and induction of the Psp response in Escherichia coli.

    Science.gov (United States)

    Jovanovic, Goran; Engl, Christoph; Mayhew, Antony J; Burrows, Patricia C; Buck, Martin

    2010-10-01

    The phage-shock-protein (Psp) response maintains the proton-motive force (pmf) under extracytoplasmic stress conditions that impair the inner membrane (IM) in bacterial cells. In Escherichia coli transcription of the pspABCDE and pspG genes requires activation of σ(54)-RNA polymerase by the enhancer-binding protein PspF. A regulatory network comprising PspF-A-C-B-ArcB controls psp expression. One key regulatory point is the negative control of PspF imposed by its binding to PspA. It has been proposed that under stress conditions, the IM-bound sensors PspB and PspC receive and transduce the signal(s) to PspA via protein-protein interactions, resulting in the release of the PspA-PspF inhibitory complex and the consequent induction of psp. In this work we demonstrate that PspB self-associates and interacts with PspC via putative IM regions. We present evidence suggesting that PspC has two topologies and that conserved residue G48 and the putative leucine zipper motif are determinants required for PspA interaction and signal transduction upon stress. We also establish that PspC directly interacts with the effector PspG, and show that PspG self-associates. These results are discussed in the context of formation and function of the Psp regulatory complex.

  20. Human herpesvirus 8 interferon regulatory factor-mediated BH3-only protein inhibition via Bid BH3-B mimicry.

    Directory of Open Access Journals (Sweden)

    Young Bong Choi

    Full Text Available Viral replication efficiency is in large part governed by the ability of viruses to counteract pro-apoptotic signals induced by infection of host cells. For HHV-8, viral interferon regulatory factor-1 (vIRF-1 contributes to this process in part via inhibitory interactions with BH3-only protein (BOP Bim, recently identified as an interaction partner of vIRF-1. Here we recognize that the Bim-binding domain (BBD of vIRF-1 resembles a region (BH3-B of Bid, another BOP, which interacts intramolecularly with the functional BH3 domain of Bid to inhibit it pro-apoptotic activity. Indeed, vIRF-1 was found to target Bid in addition to Bim and to interact, via its BBD region, with the BH3 domain of each. In functional assays, BBD could substitute for BH3-B in the context of Bid, to suppress Bid-induced apoptosis in a BH3-binding-dependent manner, and vIRF-1 was able to protect transfected cells from apoptosis induced by Bid. While vIRF-1 can mediate nuclear sequestration of Bim, this was not the case for Bid, and inhibition of Bid and Bim by vIRF-1 could occur independently of nuclear localization of the viral protein. Consistent with this finding, direct BBD-dependent inactivation by vIRF-1 of Bid-induced mitochondrial permeabilization was demonstrable in vitro and isolated BBD sequences were also active in this assay. In addition to Bim and Bid BH3 domains, BH3s of BOPs Bik, Bmf, Hrk, and Noxa also were found to bind BBD, while those of both pro- and anti-apoptotic multi-BH domain Bcl-2 proteins were not. Finally, the significance of Bid to virus replication was demonstrated via Bid-depletion in HHV-8 infected cells, which enhanced virus production. Together, our data demonstrate and characterize BH3 targeting and associated inhibition of BOP pro-apoptotic activity by vIRF-1 via Bid BH3-B mimicry, identifying a novel mechanism of viral evasion from host cell defenses.

  1. Intramolecular and intermolecular fluorescence resonance energy transfer in fluorescent protein-tagged Na-K-Cl cotransporter (NKCC1): sensitivity to regulatory conformational change and cell volume.

    Science.gov (United States)

    Pedersen, Meike; Carmosino, Monica; Forbush, Biff

    2008-02-01

    To examine the structure and function of the Na-K-Cl cotransporter, NKCC1, we tagged the transporter with cyan (CFP) and yellow (YFP) fluorescent proteins and measured fluorescence resonance energy transfer (FRET) in stably expressing human embryonic kidney cell lines. Fluorescent protein tags were added at the N-terminal residue between the regulatory domain and the membrane domain and within a poorly conserved region of the C terminus. Both singly and doubly tagged NKCC1s were appropriately trafficked to the cell membrane and were fully functional; regulation was normal except when YFP was inserted near the regulatory domain, in which case activation occurred only upon incubation with calyculin A. Quenching of YFP fluorescence by Cl(-) provided a ratiometric indicator of intracellular [Cl(-)]. All of the CFP/YFP NKCC pairs exhibited some level of FRET, demonstrating the presence of dimers or higher multimers in functioning NKCC1. With YFP near the regulatory domain and CFP in the C terminus, we recorded a 6% FRET change signaling the regulatory phosphorylation event. On the other hand, when the probe was placed at the extreme N terminus, such changes were not seen, presumably due to the length and predicted flexibility of the N terminus. Substantial FRET changes were observed contemporaneous with cell volume changes, possibly reflective of an increase in molecular crowding upon cell shrinkage.

  2. Novel 5' untranslated region directed blockers of iron-regulatory protein-1 dependent amyloid precursor protein translation: implications for down syndrome and Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Sanghamitra Bandyopadhyay

    Full Text Available We reported that iron influx drives the translational expression of the neuronal amyloid precursor protein (APP, which has a role in iron efflux. This is via a classic release of repressor interaction of APP mRNA with iron-regulatory protein-1 (IRP1 whereas IRP2 controls the mRNAs encoding the L- and H-subunits of the iron storage protein, ferritin. Here, we identified thirteen potent APP translation blockers that acted selectively towards the uniquely configured iron-responsive element (IRE RNA stem loop in the 5' untranslated region (UTR of APP mRNA. These agents were 10-fold less inhibitory of 5'UTR sequences of the related prion protein (PrP mRNA. Western blotting confirmed that the 'ninth' small molecule in the series selectively reduced neural APP production in SH-SY5Y cells at picomolar concentrations without affecting viability or the expression of α-synuclein and ferritin. APP blocker-9 (JTR-009, a benzimidazole, reduced the production of toxic Aβ in SH-SY5Y neuronal cells to a greater extent than other well tolerated APP 5'UTR-directed translation blockers, including posiphen, that were shown to limit amyloid burden in mouse models of Alzheimer's disease (AD. RNA binding assays demonstrated that JTR-009 operated by preventing IRP1 from binding to the IRE in APP mRNA, while maintaining IRP1 interaction with the H-ferritin IRE RNA stem loop. Thus, JTR-009 constitutively repressed translation driven by APP 5'UTR sequences. Calcein staining showed that JTR-009 did not indirectly change iron uptake in neuronal cells suggesting a direct interaction with the APP 5'UTR. These studies provide key data to develop small molecules that selectively reduce neural APP and Aβ production at 10-fold lower concentrations than related previously characterized translation blockers. Our data evidenced a novel therapeutic strategy of potential impact for people with trisomy of the APP gene on chromosome 21, which is a phenotype long associated with Down

  3. Novel 5' untranslated region directed blockers of iron-regulatory protein-1 dependent amyloid precursor protein translation: implications for down syndrome and Alzheimer's disease.

    Science.gov (United States)

    Bandyopadhyay, Sanghamitra; Cahill, Catherine; Balleidier, Amelie; Huang, Conan; Lahiri, Debomoy K; Huang, Xudong; Rogers, Jack T

    2013-01-01

    We reported that iron influx drives the translational expression of the neuronal amyloid precursor protein (APP), which has a role in iron efflux. This is via a classic release of repressor interaction of APP mRNA with iron-regulatory protein-1 (IRP1) whereas IRP2 controls the mRNAs encoding the L- and H-subunits of the iron storage protein, ferritin. Here, we identified thirteen potent APP translation blockers that acted selectively towards the uniquely configured iron-responsive element (IRE) RNA stem loop in the 5' untranslated region (UTR) of APP mRNA. These agents were 10-fold less inhibitory of 5'UTR sequences of the related prion protein (PrP) mRNA. Western blotting confirmed that the 'ninth' small molecule in the series selectively reduced neural APP production in SH-SY5Y cells at picomolar concentrations without affecting viability or the expression of α-synuclein and ferritin. APP blocker-9 (JTR-009), a benzimidazole, reduced the production of toxic Aβ in SH-SY5Y neuronal cells to a greater extent than other well tolerated APP 5'UTR-directed translation blockers, including posiphen, that were shown to limit amyloid burden in mouse models of Alzheimer's disease (AD). RNA binding assays demonstrated that JTR-009 operated by preventing IRP1 from binding to the IRE in APP mRNA, while maintaining IRP1 interaction with the H-ferritin IRE RNA stem loop. Thus, JTR-009 constitutively repressed translation driven by APP 5'UTR sequences. Calcein staining showed that JTR-009 did not indirectly change iron uptake in neuronal cells suggesting a direct interaction with the APP 5'UTR. These studies provide key data to develop small molecules that selectively reduce neural APP and Aβ production at 10-fold lower concentrations than related previously characterized translation blockers. Our data evidenced a novel therapeutic strategy of potential impact for people with trisomy of the APP gene on chromosome 21, which is a phenotype long associated with Down syndrome (DS

  4. Metabolic control analysis of xylose catabolism in Aspergillus

    DEFF Research Database (Denmark)

    Prathumpai, Wai; Gabelgaard, J.B.; Wanchanthuek, P.

    2003-01-01

    A kinetic model for xylose catabolism in Aspergillus is proposed. From a thermodynamic analysis it was found that the intermediate xylitol will accumulate during xylose catabolism. Use of the kinetic model allowed metabolic control analysis (MCA) of the xylose catabolic pathway to be carried out......, and flux control was shown to be dependent on the metabolite levels. Due to thermodynamic constraints, flux control may reside at the first step in the pathway, i.e., at the xylose reductase, even when the intracellular xylitol concentration is high. On the basis of the kinetic analysis, the general dogma...... specifying that flux control often resides at the step following an intermediate present at high concentrations was, therefore, shown not to hold. The intracellular xylitol concentration was measured in batch cultivations of two different strains of Aspergillus niger and two different strains of Aspergillus...

  5. Bioanalytical approaches for characterizing catabolism of antibody-drug conjugates.

    Science.gov (United States)

    Saad, Ola M; Shen, Ben-Quan; Xu, Keyang; Khojasteh, S Cyrus; Girish, Sandhya; Kaur, Surinder

    2015-01-01

    The in vivo stability and catabolism of antibody-drug conjugates (ADCs) directly impact their PK, efficacy and safety, and metabolites of the cytotoxic or small molecule drug component of an ADC can further complicate these factors. This perspective highlights the importance of understanding ADC catabolism and the associated bioanalytical challenges. We evaluated different bioanalytical approaches to qualitatively and quantitatively characterize ADC catabolites. Here we review and discuss the rationale and experimental strategies used to design bioanalytical assays for characterization of ADC catabolism and supporting ADME studies during ADC clinical development. This review covers both large and small molecule approaches, and uses examples from Kadcyla® (T-DM1) and a THIOMAB™ antibody-drug conjugate to illustrate the process.

  6. Comparative analysis of mRNA targets for human PUF-family proteins suggests extensive interaction with the miRNA regulatory system.

    Directory of Open Access Journals (Sweden)

    Alessia Galgano

    Full Text Available Genome-wide identification of mRNAs regulated by RNA-binding proteins is crucial to uncover post-transcriptional gene regulatory systems. The conserved PUF family RNA-binding proteins repress gene expression post-transcriptionally by binding to sequence elements in 3'-UTRs of mRNAs. Despite their well-studied implications for development and neurogenesis in metazoa, the mammalian PUF family members are only poorly characterized and mRNA targets are largely unknown. We have systematically identified the mRNAs associated with the two human PUF proteins, PUM1 and PUM2, by the recovery of endogenously formed ribonucleoprotein complexes and the analysis of associated RNAs with DNA microarrays. A largely overlapping set comprised of hundreds of mRNAs were reproducibly associated with the paralogous PUM proteins, many of them encoding functionally related proteins. A characteristic PUF-binding motif was highly enriched among PUM bound messages and validated with RNA pull-down experiments. Moreover, PUF motifs as well as surrounding sequences exhibit higher conservation in PUM bound messages as opposed to transcripts that were not found to be associated, suggesting that PUM function may be modulated by other factors that bind conserved elements. Strikingly, we found that PUF motifs are enriched around predicted miRNA binding sites and that high-confidence miRNA binding sites are significantly enriched in the 3'-UTRs of experimentally determined PUM1 and PUM2 targets, strongly suggesting an interaction of human PUM proteins with the miRNA regulatory system. Our work suggests extensive connections between the RBP and miRNA post-transcriptional regulatory systems and provides a framework for deciphering the molecular mechanism by which PUF proteins regulate their target mRNAs.

  7. Comparative analysis of mRNA targets for human PUF-family proteins suggests extensive interaction with the miRNA regulatory system.

    Science.gov (United States)

    Galgano, Alessia; Forrer, Michael; Jaskiewicz, Lukasz; Kanitz, Alexander; Zavolan, Mihaela; Gerber, André P

    2008-09-08

    Genome-wide identification of mRNAs regulated by RNA-binding proteins is crucial to uncover post-transcriptional gene regulatory systems. The conserved PUF family RNA-binding proteins repress gene expression post-transcriptionally by binding to sequence elements in 3'-UTRs of mRNAs. Despite their well-studied implications for development and neurogenesis in metazoa, the mammalian PUF family members are only poorly characterized and mRNA targets are largely unknown. We have systematically identified the mRNAs associated with the two human PUF proteins, PUM1 and PUM2, by the recovery of endogenously formed ribonucleoprotein complexes and the analysis of associated RNAs with DNA microarrays. A largely overlapping set comprised of hundreds of mRNAs were reproducibly associated with the paralogous PUM proteins, many of them encoding functionally related proteins. A characteristic PUF-binding motif was highly enriched among PUM bound messages and validated with RNA pull-down experiments. Moreover, PUF motifs as well as surrounding sequences exhibit higher conservation in PUM bound messages as opposed to transcripts that were not found to be associated, suggesting that PUM function may be modulated by other factors that bind conserved elements. Strikingly, we found that PUF motifs are enriched around predicted miRNA binding sites and that high-confidence miRNA binding sites are significantly enriched in the 3'-UTRs of experimentally determined PUM1 and PUM2 targets, strongly suggesting an interaction of human PUM proteins with the miRNA regulatory system. Our work suggests extensive connections between the RBP and miRNA post-transcriptional regulatory systems and provides a framework for deciphering the molecular mechanism by which PUF proteins regulate their target mRNAs.

  8. The DtxR protein acting as dual transcriptional regulator directs a global regulatory network involved in iron metabolism of Corynebacterium glutamicum

    Directory of Open Access Journals (Sweden)

    Hüser Andrea T

    2006-02-01

    Full Text Available Abstract Background The knowledge about complete bacterial genome sequences opens the way to reconstruct the qualitative topology and global connectivity of transcriptional regulatory networks. Since iron is essential for a variety of cellular processes but also poses problems in biological systems due to its high toxicity, bacteria have evolved complex transcriptional regulatory networks to achieve an effective iron homeostasis. Here, we apply a combination of transcriptomics, bioinformatics, in vitro assays, and comparative genomics to decipher the regulatory network of the iron-dependent transcriptional regulator DtxR of Corynebacterium glutamicum. Results A deletion of the dtxR gene of C. glutamicum ATCC 13032 led to the mutant strain C. glutamicum IB2103 that was able to grow in minimal medium only under low-iron conditions. By performing genome-wide DNA microarray hybridizations, differentially expressed genes involved in iron metabolism of C. glutamicum were detected in the dtxR mutant. Bioinformatics analysis of the genome sequence identified a common 19-bp motif within the upstream region of 31 genes, whose differential expression in C. glutamicum IB2103 was verified by real-time reverse transcription PCR. Binding of a His-tagged DtxR protein to oligonucleotides containing the 19-bp motifs was demonstrated in vitro by DNA band shift assays. At least 64 genes encoding a variety of physiological functions in iron transport and utilization, in central carbohydrate metabolism and in transcriptional regulation are controlled directly by the DtxR protein. A comparison with the bioinformatically predicted networks of C. efficiens, C. diphtheriae and C. jeikeium identified evolutionary conserved elements of the DtxR network. Conclusion This work adds considerably to our currrent understanding of the transcriptional regulatory network of C. glutamicum genes that are controlled by DtxR. The DtxR protein has a major role in controlling the

  9. Essential amino acid leucine and proteasome inhibitor MG132 attenuate cigarette smoke induced catabolism in C2 myotubes.

    Science.gov (United States)

    Rom, Oren; Kaisari, Sharon; Aizenbud, Dror; Reznick, A Z

    2013-01-01

    Exposure to cigarette smoke (CS) and cigarette smoking have been shown to promote catabolism of skeletal muscle. Previous studies and recent findings from our laboratory have demonstrated the involvement of the ubiquitin proteasome system and the muscle-specific E3 ubiquitin ligases MAFbx/atrogin-1 and MuRF1 in CS induced skeletal muscle catabolism. The essential amino acid leucine is a known anticatabolic agent that improves skeletal muscle metabolism in various atrophic conditions. To examine the protective effect of leucine and proteasome inhibition in CS induced muscle catabolism, C2 myotubes, from an in vitro skeletal muscle cell line, were exposed to CS in the presence or absence of leucine and a proteasome inhibitor, MG132. Diameter of myotubes, levels of the main contractile proteins - myosin heavy chain and actin, expression of MAFbx/atrogin-1 and MuRF1 were studied by microscopy, Western blotting, and qPCR. Leucine pretreatment prevented the CS-induced reduction in diameter of myotubes and degradation of myosin heavy chain by suppressing the upregulation of MAFbx/atrogin-1 and MuRF1. MG132 also attenuated the CS-induced decrease in diameter of myotubes and degradation of myosin heavy chain. Our findings demonstrate that supplementation with the essential amino acid leucine and inhibition of the proteasome may protect skeletal muscle from CS induced catabolism.

  10. 细胞周期调控蛋白与肾脏疾病%Cell cycle- regulatory proteins and kidney disease

    Institute of Scientific and Technical Information of China (English)

    秦福芳; 邵凤民

    2011-01-01

    Cell is alwayse going on cell division, proliferation, hypertrophy, necrosis, no matter what physiological reaction or pathology. And those activities are regulated by Cell cycle - regulatory proteins, the relation and relative progress of Cell cycle - regulatory proteins and kidney disease were reviewed in this paper.%无论是生理情况下或病理情况下,细胞都在进行着分裂、增殖、肥大或凋亡与坏死,而这一系列细胞分裂增殖活动受到细胞周期调控蛋白的调节.本文主要就细胞周期调控蛋白与肾脏疾病之间的关系和相关进展作一综述.

  11. MAP kinases Erk1/2 phosphorylate sterol regulatory element-binding protein (SREBP)-1a at serine 117 in vitro.

    Science.gov (United States)

    Roth, G; Kotzka, J; Kremer, L; Lehr, S; Lohaus, C; Meyer, H E; Krone, W; Müller-Wieland, D

    2000-10-27

    Sterol regulatory element-binding protein (SREBP)-1a is a transcription factor sensing cellular cholesterol levels and integrating gene regulatory signals mediated by MAP kinase cascades. Here we report the identification of serine 117 in SREBP-1a as the major phosphorylation site of the MAP kinases Erk1/2. This site was identified by nanoelectrospray mass spectrometry and peptide sequencing of recombinant fusion proteins phosphorylated by Erk1/2 in vitro. Serine 117 was verified as the major phosphorylation site by in vitro mutagenesis. Mutation of serine 117 to alanine abolished Erk2-mediated phosphorylation in vitro and the MAP kinase-related transcriptional activation of SREBP-1a by insulin and platelet-derived growth factor in vivo. Our data indicate that the MAP kinase-mediated effects on SREBP-1a-regulated target genes are linked to this phosphorylation site.

  12. Effects of retinoic acid and hydrogen peroxide on sterol regulatory element-binding protein-1a activation during adipogenic differentiation of 3T3-L1 cells

    OpenAIRE

    Eldaim, Mabrouk A. Abd; Okamatsu-Ogura, Yuko; Terao, Akira; Kimura, Kazuhiro

    2010-01-01

    Both retinoic acid (RA) and oxidative stress (H2O2) increased transcription and cleavage of membrane-bound sterol regulatory element-binding protein (SREBP)-1, leading to enhanced transcription of fatty acid synthase (FAS) in hepatoma cells. On the other hand, RA and H2O2 decreased and increased lipogenesis in adipocytes, respectively, although roles of SREBP-1 activation in these effects remain to be elucidated. To elucidate its involvement, we examined the activation of SREBP...

  13. Comprehensive behavioral analysis of voltage-gated calcium channel beta-anchoring and -regulatory protein knockout mice

    Directory of Open Access Journals (Sweden)

    Akito eNakao

    2015-06-01

    Full Text Available Calcium (Ca2+ influx through voltage-gated Ca2+ channels (VGCCs induces numerous intracellular events such as neuronal excitability, neurotransmitter release, synaptic plasticity, and gene regulation. It has been shown that genes related to Ca2+ signaling, such as the CACNA1C, CACNB2, and CACNA1I genes that encode VGCC subunits, are associated with schizophrenia and other psychiatric disorders. Recently, VGCC beta-anchoring and -regulatory protein (BARP was identified as a novel regulator of VGCC activity via the interaction of VGCC β subunits. To examine the role of the BARP in higher brain functions, we generated BARP knockout (KO mice and conducted a comprehensive battery of behavioral tests. BARP KO mice exhibited greatly reduced locomotor activity, as evidenced by decreased vertical activity, stereotypic counts in the open field test, and activity level in the home cage, and longer latency to complete a session in spontaneous T-maze alteration test, which reached study-wide significance. Acoustic startle response was also reduced in the mutants. Interestingly, they showed multiple behavioral phenotypes that are seemingly opposite to those seen in the mouse models of schizophrenia and its related disorders, including increased working memory, flexibility, prepulse inhibition, and social interaction, and decreased locomotor activity, though many of these phenotypes are statistically weak and require further replications. These results demonstrate that BARP is involved in the regulation of locomotor activity and, possibly, emotionality. The possibility was also suggested that BARP KO mice may serve as a unique tool for investigating the pathogenesis/pathophysiology of schizophrenia and related disorders. Further evaluation of the molecular and physiological phenotypes of the mutant mice would provide new insights into the role of BARP in higher brain functions.

  14. Sterol regulatory element-binding proteins are regulators of the rat thyroid peroxidase gene in thyroid cells.

    Directory of Open Access Journals (Sweden)

    Christine Rauer

    Full Text Available Sterol regulatory element-binding proteins (SREBPs-1c and -2, which were initially discovered as master transcriptional regulators of lipid biosynthesis and uptake, were recently identified as novel transcriptional regulators of the sodium-iodide symporter gene in the thyroid, which is essential for thyroid hormone synthesis. Based on this observation that SREBPs play a role for thyroid hormone synthesis, we hypothesized that another gene involved in thyroid hormone synthesis, the thyroid peroxidase (TPO gene, is also a target of SREBP-1c and -2. Thyroid epithelial cells treated with 25-hydroxycholesterol, which is known to inhibit SREBP activation, had about 50% decreased mRNA levels of TPO. Similarly, the mRNA level of TPO was reduced by about 50% in response to siRNA mediated knockdown of both, SREBP-1 and SREBP-2. Reporter gene assays revealed that overexpression of active SREBP-1c and -2 causes a strong transcriptional activation of the rat TPO gene, which was localized to an approximately 80 bp region in the intron 1 of the rat TPO gene. In vitro- and in vivo-binding of both, SREBP-1c and SREBP-2, to this region in the rat TPO gene could be demonstrated using gel-shift assays and chromatin immunoprecipitation. Mutation analysis of the 80 bp region of rat TPO intron 1 revealed two isolated and two overlapping SREBP-binding elements from which one, the overlapping SRE+609/InvSRE+614, was shown to be functional in reporter gene assays. In connection with recent findings that the rat NIS gene is also a SREBP target gene in the thyroid, the present findings suggest that SREBPs may be possible novel targets for pharmacological modulation of thyroid hormone synthesis.

  15. Dynamic changes in binding of immunoglobulin heavy chain 3' regulatory region to protein factors during class switching.

    Science.gov (United States)

    Chatterjee, Sanjukta; Ju, Zhongliang; Hassan, Rabih; Volpi, Sabrina A; Emelyanov, Alexander V; Birshtein, Barbara K

    2011-08-19

    The 3' regulatory region (3' RR) of the Igh locus works at long distances on variable region (V(H)) and switch region (I) region promoters to initiate germ line (non-coding) transcription (GT) and promote class switch recombination (CSR). The 3' RR contains multiple elements, including enhancers (hs3a, hs1.2, hs3b, and hs4) and a proposed insulator region containing CTCF (CCCTC-binding factor) binding sites, i.e. hs5/6/7 and the downstream region ("38"). Notably, deletion of each individual enhancer (hs3a-hs4) has no significant phenotypic consequence, suggesting that the 3' RR has considerable structural flexibility in its function. To better understand how the 3' RR functions, we identified transcription factor binding sites and used chromatin immunoprecipitation (ChIP) assays to monitor their occupancy in splenic B cells that initiate GT and undergo CSR (LPS±IL4), are deficient in GT and CSR (p50(-/-)), or do not undergo CSR despite efficient GT (anti-IgM+IL4). Like 3' RR enhancers, hs5-7 and the 38 region were observed to contain multiple Pax5 binding sites (in addition to multiple CTCF sites). We found that the Pax5 binding profile to the 3' RR dynamically changed during CSR independent of the specific isotype to which switching was induced, and binding focused on hs1.2, hs4, and hs7. CTCF-associated and CTCF-independent cohesin interactions were also identified. Our observations are consistent with a scaffold model in which a platform of active protein complexes capable of facilitating GT and CSR can be formed by varying constellations of 3' RR elements.

  16. Steroidogenic acute regulatory protein (StAR) overexpression attenuates HFD-induced hepatic steatosis and insulin resistance.

    Science.gov (United States)

    Qiu, Yanyan; Sui, Xianxian; Zhan, Yongkun; Xu, Chen; Li, Xiaobo; Ning, Yanxia; Zhi, Xiuling; Yin, Lianhua

    2017-04-01

    Non-alcoholic fatty liver disease (NAFLD) covers a wide spectrum of liver pathology. Intracellular lipid accumulation is the first step in the development and progression of NAFLD. Steroidogenic acute regulatory protein (StAR) plays an important role in the synthesis of bile acid and intracellular lipid homeostasis and cholesterol metabolism. We hypothesize that StAR is involved in non-alcoholic fatty liver disease (NAFLD) pathogenesis. The hypothesis was identified using free fatty acid (FFA)-overloaded NAFLD in vitro model and high-fat diet (HFD)-induced NAFLD mouse model transfected by recombinant adenovirus encoding StAR (StAR). StAR expression was also examined in pathology samples of patients with fatty liver by immunohistochemical staining. We found that the expression level of StAR was reduced in the livers obtained from fatty liver patients and NAFLD mice. Additionally, StAR overexpression decreased the levels of hepatic lipids and maintained the hepatic glucose homeostasis due to the activation of farnesoid x receptor (FXR). StAR overexpression attenuated the impairment of insulin signaling in fatty liver. This protective role of StAR was owing to a reduction of intracellular diacylglycerol levels and the phosphorylation of PKCε. Furthermore, FXR inactivation reversed the observed beneficial effects of StAR. The present study revealed that StAR overexpression can reduce hepatic lipid accumulation, regulate glucose metabolism and attenuate insulin resistance through a mechanism involving the activation of FXR. Our study suggests that StAR may be a potential therapeutic target for NAFLD.

  17. High concentrations of protein test substances may have non-toxic effects on Daphnia magna: Implications for regulatory study designs and ecological risk assessments for GM crops

    Science.gov (United States)

    Raybould, Alan; Burns, Andrea; Hamer, Mick

    2014-01-01

    Laboratory testing for possible adverse effects of insecticidal proteins on non-target organisms (NTOs) is an important part of many ecological risk assessments for regulatory decision-making about the cultivation of insect-resistant genetically modified (IRGM) crops. To increase confidence in the risk assessments, regulatory guidelines for effects testing specify that representative surrogate species for NTOs are exposed to concentrations of insecticidal proteins that are in excess of worst-case predicted exposures in the field. High concentrations in effects tests are achieved by using protein test substances produced in microbes, such as Escherichia coli. In a study that exposed Daphnia magna to a single high concentration of a microbial test substance containing Vip3Aa20, the insecticidal protein in MIR162 maize, small reductions in growth were observed. These effects were surprising as many other studies strongly suggest that the activity of Vip3Aa20 is limited to Lepidoptera. A plausible explanation for the effect on growth is that high concentrations of test substance have a non-toxic effect on Daphnia, perhaps by reducing its feeding rate. A follow-up study tested that hypothesis by exposing D. magna to several concentrations of Vip3Aa20, and a high concentration of a non-toxic protein, bovine serum albumin (BSA). Vip3Aa20 and BSA had sporadic effects on the reproduction and growth of D. magna. The pattern of the effects suggests that they result from non-toxic effects of high concentrations of protein, and not from toxicity. The implications of these results for regulatory NTO effects testing and ERA of IRGM crops are discussed. PMID:25523175

  18. High concentrations of protein test substances may have non-toxic effects on Daphnia magna: implications for regulatory study designs and ecological risk assessments for GM crops.

    Science.gov (United States)

    Raybould, Alan; Burns, Andrea; Hamer, Mick

    2014-01-01

    Laboratory testing for possible adverse effects of insecticidal proteins on non-target organisms (NTOs) is an important part of many ecological risk assessments for regulatory decision-making about the cultivation of insect-resistant genetically modified (IRGM) crops. To increase confidence in the risk assessments, regulatory guidelines for effects testing specify that representative surrogate species for NTOs are exposed to concentrations of insecticidal proteins that are in excess of worst-case predicted exposures in the field. High concentrations in effects tests are achieved by using protein test substances produced in microbes, such as Escherichia coli. In a study that exposed Daphnia magna to a single high concentration of a microbial test substance containing Vip3Aa20, the insecticidal protein in MIR162 maize, small reductions in growth were observed. These effects were surprising as many other studies strongly suggest that the activity of Vip3Aa20 is limited to Lepidoptera. A plausible explanation for the effect on growth is that high concentrations of test substance have a non-toxic effect on Daphnia, perhaps by reducing its feeding rate. A follow-up study tested that hypothesis by exposing D. magna to several concentrations of Vip3Aa20, and a high concentration of a non-toxic protein, bovine serum albumin (BSA). Vip3Aa20 and BSA had sporadic effects on the reproduction and growth of D. magna. The pattern of the effects suggests that they result from non-toxic effects of high concentrations of protein, and not from toxicity. The implications of these results for regulatory NTO effects testing and ERA of IRGM crops are discussed.

  19. Differential roles of regulatory light chain and myosin binding protein-C phosphorylations in the modulation of cardiac force development

    Energy Technology Data Exchange (ETDEWEB)

    Colson, Brett A.; Locher, Matthew R.; Bekyarova, Tanya; Patel, Jitandrakumar R.; Fitzsimons, Daniel P.; Irving, Thomas C.; Moss, Richard L. (IIT); (UW-MED)

    2010-05-25

    Phosphorylation of myosin regulatory light chain (RLC) by myosin light chain kinase (MLCK) and myosin binding protein-C (cMyBP-C) by protein kinase A (PKA) independently accelerate the kinetics of force development in ventricular myocardium. However, while MLCK treatment has been shown to increase the Ca{sup 2+} sensitivity of force (pCa{sub 50}), PKA treatment has been shown to decrease pCa{sub 50}, presumably due to cardiac troponin I phosphorylation. Further, MLCK treatment increases Ca{sup 2+}-independent force and maximum Ca{sup 2+}-activated force, whereas PKA treatment has no effect on either force. To investigate the structural basis underlying the kinase-specific differential effects on steady-state force, we used synchrotron low-angle X-ray diffraction to compare equatorial intensity ratios (I{sub 1,1}/I{sub 1,0}) to assess the proximity of myosin cross-bridge mass relative to actin and to compare lattice spacings (d{sub 1,0}) to assess the inter-thick filament spacing in skinned myocardium following treatment with either MLCK or PKA. As we showed previously, PKA phosphorylation of cMyBP-C increases I{sub 1,1}/I{sub 1,0} and, as hypothesized, treatment with MLCK also increased I{sub 1,1}/I{sub 1,0}, which can explain the accelerated rates of force development during activation. Importantly, interfilament spacing was reduced by {approx}2 nm ({Delta} 3.5%) with MLCK treatment, but did not change with PKA treatment. Thus, RLC or cMyBP-C phosphorylation increases the proximity of cross-bridges to actin, but only RLC phosphorylation affects lattice spacing, which suggests that RLC and cMyBP-C modulate the kinetics of force development by similar structural mechanisms; however, the effect of RLC phosphorylation to increase the Ca{sup 2+} sensitivity of force is mediated by a distinct mechanism, most probably involving changes in interfilament spacing.

  20. Identification of a phosphorylation-dependent nuclear localization motif in interferon regulatory factor 2 binding protein 2.

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    Allen C T Teng

    Full Text Available BACKGROUND: Interferon regulatory factor 2 binding protein 2 (IRF2BP2 is a muscle-enriched transcription factor required to activate vascular endothelial growth factor-A (VEGFA expression in muscle. IRF2BP2 is found in the nucleus of cardiac and skeletal muscle cells. During the process of skeletal muscle differentiation, some IRF2BP2 becomes relocated to the cytoplasm, although the functional significance of this relocation and the mechanisms that control nucleocytoplasmic localization of IRF2BP2 are not yet known. METHODOLOGY/PRINCIPAL FINDINGS: Here, by fusing IRF2BP2 to green fluorescent protein and testing a series of deletion and site-directed mutagenesis constructs, we mapped the nuclear localization signal (NLS to an evolutionarily conserved sequence (354ARKRKPSP(361 in IRF2BP2. This sequence corresponds to a classical nuclear localization motif bearing positively charged arginine and lysine residues. Substitution of arginine and lysine with negatively charged aspartic acid residues blocked nuclear localization. However, these residues were not sufficient because nuclear targeting of IRF2BP2 also required phosphorylation of serine 360 (S360. Many large-scale phosphopeptide proteomic studies had reported previously that serine 360 of IRF2BP2 is phosphorylated in numerous human cell types. Alanine substitution at this site abolished IRF2BP2 nuclear localization in C(2C(12 myoblasts and CV1 cells. In contrast, substituting serine 360 with aspartic acid forced nuclear retention and prevented cytoplasmic redistribution in differentiated C(2C(12 muscle cells. As for the effects of these mutations on VEGFA promoter activity, the S360A mutation interfered with VEGFA activation, as expected. Surprisingly, the S360D mutation also interfered with VEGFA activation, suggesting that this mutation, while enforcing nuclear entry, may disrupt an essential activation function of IRF2BP2. CONCLUSIONS/SIGNIFICANCE: Nuclear localization of IRF2BP2 depends on

  1. α -Actinin TvACTN3 of Trichomonas vaginalis is an RNA-binding protein that could participate in its posttranscriptional iron regulatory mechanism.

    Science.gov (United States)

    Calla-Choque, Jaeson Santos; Figueroa-Angulo, Elisa Elvira; Ávila-González, Leticia; Arroyo, Rossana

    2014-01-01

    Trichomonas vaginalis is a sexually transmitted flagellated protist parasite responsible for trichomoniasis. This parasite is dependent on high levels of iron, favoring its growth and multiplication. Iron also differentially regulates some trichomonad virulence properties by unknown mechanisms. However, there is evidence to support the existence of gene regulatory mechanisms at the transcriptional and posttranscriptional levels that are mediated by iron concentration in T. vaginalis. Thus, the goal of this study was to identify an RNA-binding protein in T. vaginalis that interacts with the tvcp4 RNA stem-loop structure, which may participate in a posttranscriptional iron regulatory mechanism mediated by RNA-protein interactions. We performed RNA electrophoretic mobility shift assay (REMSA) and supershift, UV cross-linking, Northwestern blot, and western blot (WB) assays using cytoplasmic protein extracts from T. vaginalis with the tvcp4 RNA hairpin structure as a probe. We identified a 135-kDa protein isolated by the UV cross-linking assays as α-actinin 3 (TvACTN3) by MALDI-TOF-MS that was confirmed by LS-MS/MS and de novo sequencing. TvACTN3 is a cytoplasmic protein that specifically binds to hairpin RNA structures from trichomonads and humans when the parasites are grown under iron-depleted conditions. Thus, TvACTN3 could participate in the regulation of gene expression by iron in T. vaginalis through a parallel posttranscriptional mechanism similar to that of the IRE/IRP system.

  2. Yeast sterol regulatory element-binding protein (SREBP) cleavage requires Cdc48 and Dsc5, a ubiquitin regulatory X domain-containing subunit of the Golgi Dsc E3 ligase.

    Science.gov (United States)

    Stewart, Emerson V; Lloyd, S Julie-Ann; Burg, John S; Nwosu, Christine C; Lintner, Robert E; Daza, Riza; Russ, Carsten; Ponchner, Karen; Nusbaum, Chad; Espenshade, Peter J

    2012-01-01

    Schizosaccharomyces pombe Sre1 is a membrane-bound transcription factor that controls adaptation to hypoxia. Like its mammalian homolog, sterol regulatory element-binding protein (SREBP), Sre1 activation requires release from the membrane. However, in fission yeast, this release occurs through a strikingly different mechanism that requires the Golgi Dsc E3 ubiquitin ligase complex and the proteasome. The mechanistic details of Sre1 cleavage, including the link between the Dsc E3 ligase complex and proteasome, are not well understood. Here, we present results of a genetic selection designed to identify additional components required for Sre1 cleavage. From the selection, we identified two new components of the fission yeast SREBP pathway: Dsc5 and Cdc48. The AAA (ATPase associated with diverse cellular activities) ATPase Cdc48 and Dsc5, a ubiquitin regulatory X domain-containing protein, interact with known Dsc complex components and are required for SREBP cleavage. These findings provide a mechanistic link between the Dsc E3 ligase complex and the proteasome in SREBP cleavage and add to a growing list of similarities between the Dsc E3 ligase and membrane E3 ligases involved in endoplasmic reticulum-associated degradation.

  3. Methanesulfonate (MSA) Catabolic Genes from Marine and Estuarine Bacteria.

    Science.gov (United States)

    Henriques, Ana C; De Marco, Paolo

    2015-01-01

    Quantitatively, methanesulfonate (MSA) is a very relevant compound in the global biogeochemical sulfur cycle. Its utilization by bacteria as a source of carbon and energy has been described and a specific enzyme, methanesulfonate monooxygenase (MSAMO), has been found to perform the first catabolic step of its oxidation. Other proteins seemingly involved in the import of MSA into bacterial cells have been reported. In this study, we obtained novel sequences of genes msmA and msmE from marine, estuary and soil MSA-degraders (encoding the large subunit of the MSAMO enzyme and the periplasmic component of the import system, respectively). We also obtained whole-genome sequences of two novel marine Filomicrobium strains, Y and W, and annotated two full msm operons in these genomes. Furthermore, msmA and msmE sequences were amplified from North Atlantic seawater and analyzed. Good conservation of the MsmA deduced protein sequence was observed in both cultured strains and metagenomic clones. A long spacer sequence in the Rieske-type [2Fe-2S] cluster-binding motif within MsmA was found to be conserved in all instances, supporting the hypothesis that this feature is specific to the large (α) subunit of the MSAMO enzyme. The msmE gene was more difficult to amplify, from both cultivated isolates and marine metagenomic DNA. However, 3 novel msmE sequences were obtained from isolated strains and one directly from seawater. With both genes, our results combined with previous metagenomic analyses seem to imply that moderate to high-GC strains are somehow favored during enrichment and isolation of MSA-utilizing bacteria, while the majority of msm genes obtained by cultivation-independent methods have low levels of GC%, which is a clear example of the misrepresentation of natural populations that culturing, more often than not, entails. Nevertheless, the data obtained in this work show that MSA-degrading bacteria are abundant in surface seawater, which suggests ecological

  4. 吲哚美辛对慢性阻塞性肺疾病大鼠肿瘤坏死因子α和骨骼肌蛋白质分解代谢的影响%The influence of indomethacin on TNFα and skeletal muscle protein catabolism in chronic obstructive pulmonary disease rat model

    Institute of Scientific and Technical Information of China (English)

    林桦; 孙圣华; 高健; 刘纯; 詹娟

    2010-01-01

    Objective To observe the influence of tumor necrosis factor-alpha(TNFα) on skeletal muscle protein catabolism in rats with chronic obstructive pulmonary disease (COPD) and the effects of indomethacin (IND) on it. Methods Duplicated COPD model rats were divided into two groups: the malnutrition group and the normal nutrition group. The malnutrition group were further divided by randomized block design into four groups. Isotonic physiologic saline was administered to group A, the control and the normal nutrition group, and different doses of oral IND were administered to groups B, C, and D weight, concentrations of TNFα, contents of 3-methyl-histidine ( 3- M H ) and tyrosine (Tyr) in the diaphragm and extensor digitorum longus muscle homogenates were measured before and after the intervention. Results Before the intervention, the concentrations of TNFα in the serum of malnutrition groups were all significantly higher than those of normal nutrition group and the control group. After the intervention: (1) The concentrations of TNFα in the serum of the rats of group B, C and D were significantly lower than the group A, especially in group C. The levels of TNFα in serum and body weight of model group rats were negatively correlated ( r = -0. 846, P <0. 01 ), as well as the diaphragm and extensor digitorum longus muscle weights ( r = - 0. 778, P < 0. 01; r = - 0. 772, P < 0. 01 ). (2) The levels of 3-methyl-histidine in the diaphragm and extensor digitorum longus muscles of the intervention group C was lower than the COPD normal nutrition group, as well as the intervention groups B and D. The contents of tyrosine in the diaphragm and extensor digitorum longus muscles of the intervention group C was lower than that of the COPD normal nutrition group,as well as the groups B and D. The body weight growth value of the intervention group B were slightly higher than the group A, without significant difference( P > 0. 05 ), while the group C was significantly higher

  5. Pathway and enzyme redundancy in putrescine catabolism in Escherichia coli.

    Science.gov (United States)

    Schneider, Barbara L; Reitzer, Larry

    2012-08-01

    Putrescine as the sole carbon source requires a novel catabolic pathway with glutamylated intermediates. Nitrogen limitation does not induce genes of this glutamylated putrescine (GP) pathway but instead induces genes for a putrescine catabolic pathway that starts with a transaminase-dependent deamination. We determined pathway utilization with putrescine as the sole nitrogen source by examining mutants with defects in both pathways. Blocks in both the GP and transaminase pathways were required to prevent growth with putrescine as the sole nitrogen source. Genetic and biochemical analyses showed redundant enzymes for γ-aminobutyraldehyde dehydrogenase (PatD/YdcW and PuuC), γ-aminobutyrate transaminase (GabT and PuuE), and succinic semialdehyde dehydrogenase (GabD and PuuC). PuuC is a nonspecific aldehyde dehydrogenase that oxidizes all the aldehydes in putrescine catabolism. A puuP mutant failed to use putrescine as the nitrogen source, which implies one major transporter for putrescine as the sole nitrogen source. Analysis of regulation of the GP pathway shows induction by putrescine and not by a product of putrescine catabolism and shows that putrescine accumulates in puuA, puuB, and puuC mutants but not in any other mutant. We conclude that two independent sets of enzymes can completely degrade putrescine to succinate and that their relative importance depends on the environment.

  6. Regulatory agencies and regulatory risk

    OpenAIRE

    Knieps, Günter; Weiß, Hans-Jörg

    2007-01-01

    The aim of this paper is to show that regulatory risk is due to the discretionary behaviour of regulatory agencies, caused by a too extensive regulatory mandate provided by the legislator. The normative point of reference and a behavioural model of regulatory agencies based on the positive theory of regulation are presented. Regulatory risk with regard to the future behaviour of regulatory agencies is modelled as the consequence of the ex ante uncertainty about the relative influence of inter...

  7. Variable carbon catabolism among Salmonella enterica serovar Typhi isolates.

    Directory of Open Access Journals (Sweden)

    Lay Ching Chai

    Full Text Available BACKGROUND: Salmonella enterica serovar Typhi (S. Typhi is strictly a human intracellular pathogen. It causes acute systemic (typhoid fever and chronic infections that result in long-term asymptomatic human carriage. S. Typhi displays diverse disease manifestations in human infection and exhibits high clonality. The principal factors underlying the unique lifestyle of S. Typhi in its human host during acute and chronic infections remain largely unknown and are therefore the main objective of this study. METHODOLOGY/PRINCIPAL FINDINGS: To obtain insight into the intracellular lifestyle of S. Typhi, a high-throughput phenotypic microarray was employed to characterise the catabolic capacity of 190 carbon sources in S. Typhi strains. The success of this study lies in the carefully selected library of S. Typhi strains, including strains from two geographically distinct areas of typhoid endemicity, an asymptomatic human carrier, clinical stools and blood samples and sewage-contaminated rivers. An extremely low carbon catabolic capacity (27% of 190 carbon substrates was observed among the strains. The carbon catabolic profiles appeared to suggest that S. Typhi strains survived well on carbon subtrates that are found abundantly in the human body but not in others. The strains could not utilise plant-associated carbon substrates. In addition, α-glycerolphosphate, glycerol, L-serine, pyruvate and lactate served as better carbon sources to monosaccharides in the S. Typhi strains tested. CONCLUSION: The carbon catabolic profiles suggest that S. Typhi could survive and persist well in the nutrient depleted metabolic niches in the human host but not in the environment outside of the host. These findings serve as caveats for future studies to understand how carbon catabolism relates to the pathogenesis and transmission of this pathogen.

  8. Hormonal regulation of leucine catabolism in mammary epithelial cells.

    Science.gov (United States)

    Lei, Jian; Feng, Dingyuan; Zhang, Yongliang; Dahanayaka, Sudath; Li, Xilong; Yao, Kang; Wang, Junjun; Wu, Zhenlong; Dai, Zhaolai; Wu, Guoyao

    2013-09-01

    Branched-chain amino acids (BCAA) are actively taken up and catabolized by the mammary gland during lactation for syntheses of glutamate, glutamine and aspartate. Available evidence shows that the onset of lactation is associated with increases in circulating levels of cortisol, prolactin and glucagon, but decreases in insulin and growth hormone. This study determined the effects of physiological concentrations of these hormones on the catabolism of leucine (a representative BCAA) in bovine mammary epithelial cells. Cells were incubated at 37 °C for 2 h in Krebs buffer containing 3 mM D-glucose, 0.5 mM L-leucine, L-[1-14C]leucine or L-[U-14C]leucine, and 0-50 μU/mL insulin, 0-20 ng/mL growth hormone 0-200 ng/mL prolactin, 0-150 nM cortisol or 0-300 pg/mL glucagon. Increasing extracellular concentrations of insulin did not affect leucine transamination or oxidative decarboxylation, but decreased the rate of oxidation of leucine carbons 2-6. Elevated levels of growth hormone dose dependently inhibited leucine catabolism, α-ketoisocaproate (KIC) production and the syntheses of glutamate plus glutamine. In contrast, cortisol and glucagon increased leucine transamination, leucine oxidative decarboxylation, KIC production, the oxidation of leucine 2-6 carbons and the syntheses of glutamate plus glutamine. Prolactin did not affect leucine catabolism in the cells. The changes in leucine degradation were consistent with alterations in abundances of BCAA transaminase and phosphorylated levels of branched-chain α-ketoacid dehydrogenase. Reductions in insulin and growth hormone but increases in cortisol and glucagon with lactation act in concert to stimulate BCAA catabolism for glutamate and glutamine syntheses. These coordinated changes in hormones may facilitate milk production in lactating mammals.

  9. A cis-regulatory mutation in troponin-I of Drosophila reveals the importance of proper stoichiometry of structural proteins during muscle assembly.

    Science.gov (United States)

    Firdaus, Hena; Mohan, Jayaram; Naz, Sarwat; Arathi, Prabhashankar; Ramesh, Saraf R; Nongthomba, Upendra

    2015-05-01

    Rapid and high wing-beat frequencies achieved during insect flight are powered by the indirect flight muscles, the largest group of muscles present in the thorax. Any anomaly during the assembly and/or structural impairment of the indirect flight muscles gives rise to a flightless phenotype. Multiple mutagenesis screens in Drosophila melanogaster for defective flight behavior have led to the isolation and characterization of mutations that have been instrumental in the identification of many proteins and residues that are important for muscle assembly, function, and disease. In this article, we present a molecular-genetic characterization of a flightless mutation, flightless-H (fliH), originally designated as heldup-a (hdp-a). We show that fliH is a cis-regulatory mutation of the wings up A (wupA) gene, which codes for the troponin-I protein, one of the troponin complex proteins, involved in regulation of muscle contraction. The mutation leads to reduced levels of troponin-I transcript and protein. In addition to this, there is also coordinated reduction in transcript and protein levels of other structural protein isoforms that are part of the troponin complex. The altered transcript and protein stoichiometry ultimately culminates in unregulated acto-myosin interactions and a hypercontraction muscle phenotype. Our results shed new insights into the importance of maintaining the stoichiometry of structural proteins during muscle assembly for proper function with implications for the identification of mutations and disease phenotypes in other species, including humans.

  10. Evaluation of global sequence comparison and one-to-one FASTA local alignment in regulatory allergenicity assessment of transgenic proteins in food crops.

    Science.gov (United States)

    Song, Ping; Herman, Rod A; Kumpatla, Siva

    2014-09-01

    To address the high false positive rate using >35% identity over 80 amino acids in the regulatory assessment of transgenic proteins for potential allergenicity and the change of E-value with database size, the Needleman-Wunsch global sequence alignment and a one-to-one (1:1) local FASTA search (one protein in the target database at a time) using FASTA were evaluated by comparing proteins randomly selected from Arabidopsis, rice, corn, and soybean with known allergens in a peer-reviewed allergen database (http://www.allergenonline.org/). Compared with the approach of searching >35%/80aa+, the false positive rate measured by specificity rate for identification of true allergens was reduced by a 1:1 global sequence alignment with a cut-off threshold of ≧30% identity and a 1:1 FASTA local alignment with a cut-off E-value of ≦1.0E-09 while maintaining the same sensitivity. Hence, a 1:1 sequence comparison, especially using the FASTA local alignment tool with a biological relevant E-value of 1.0E-09 as a threshold, is recommended for the regulatory assessment of sequence identities between transgenic proteins in food crops and known allergens.

  11. X-ray structure of a hydroxylase-regulatory protein complex from a hydrocarbon-oxidizing multicomponent monooxygenase, Pseudomonas sp. OX1 phenol hydroxylase.

    Science.gov (United States)

    Sazinsky, Matthew H; Dunten, Pete W; McCormick, Michael S; DiDonato, Alberto; Lippard, Stephen J

    2006-12-26

    Phenol hydroxylase (PH) belongs to a family of bacterial multicomponent monooxygenases (BMMs) with carboxylate-bridged diiron active sites. Included are toluene/o-xylene (ToMO) and soluble methane (sMMO) monooxygenase. PH hydroxylates aromatic compounds, but unlike sMMO, it cannot oxidize alkanes despite having a similar dinuclear iron active site. Important for activity is formation of a complex between the hydroxylase and a regulatory protein component. To address how structural features of BMM hydroxylases and their component complexes may facilitate the catalytic mechanism and choice of substrate, we determined X-ray structures of native and SeMet forms of the PH hydroxylase (PHH) in complex with its regulatory protein (PHM) to 2.3 A resolution. PHM binds in a canyon on one side of the (alphabetagamma)2 PHH dimer, contacting alpha-subunit helices A, E, and F approximately 12 A above the diiron core. The structure of the dinuclear iron center in PHH resembles that of mixed-valent MMOH, suggesting an Fe(II)Fe(III) oxidation state. Helix E, which comprises part of the iron-coordinating four-helix bundle, has more pi-helical character than analogous E helices in MMOH and ToMOH lacking a bound regulatory protein. Consequently, conserved active site Thr and Asn residues translocate to the protein surface, and an approximately 6 A pore opens through the four-helix bundle. Of likely functional significance is a specific hydrogen bond formed between this Asn residue and a conserved Ser side chain on PHM. The PHM protein covers a putative docking site on PHH for the PH reductase, which transfers electrons to the PHH diiron center prior to O2 activation, suggesting that the regulatory component may function to block undesired reduction of oxygenated intermediates during the catalytic cycle. A series of hydrophobic cavities through the PHH alpha-subunit, analogous to those in MMOH, may facilitate movement of the substrate to and/or product from the active site pocket

  12. Effects of chronic dietary selenomethionine exposure on repeat swimming performance, aerobic metabolism and methionine catabolism in adult zebrafish (Danio rerio).

    Science.gov (United States)

    Thomas, Jith K; Wiseman, Steve; Giesy, John P; Janz, David M

    2013-04-15

    swimming resulted in lesser concentrations of glycogen in the body, exposure to SeMet in the diet had no significant effect on glycogen content. Exposure to SeMet significantly down-regulated mRNA abundance of protein tyrosine phosphatase 1B (PTP 1B) in muscle, and β-hydroxyacyl coenzyme A dehydrogenase (HOAD), sterol regulatory element binding protein 1 (SREBP 1) and methionine adenosyltransferase 1 alpha (MAT 1A) in liver of adult zebrafish. Overall the results of this study suggest chronic exposure of adult zebrafish to SeMet in the diet can cause both cellular and organismal effects that could affect fitness and survivability of fish.

  13. Decreased basal chloride secretion and altered cystic fibrosis transmembrane conductance regulatory protein, Villin, GLUT5 protein expression in jejunum from leptin-deficient mice

    Directory of Open Access Journals (Sweden)

    Leung L

    2014-07-01

    Full Text Available Lana Leung, Jonathan Kang, Esa Rayyan, Ashesh Bhakta, Brennan Barrett, David Larsen, Ryan Jelinek, Justin Willey, Scott Cochran, Tom L Broderick, Layla Al-NakkashDepartment of Physiology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, AZ, USAAbstract: Patients with diabetes and obesity are at increased risk of developing disturbances in intestinal function. In this study, we characterized jejunal function in the clinically relevant leptin-deficient ob/ob mouse, a model of diabetes and obesity. We measured transepithelial short circuit current (Isc, across freshly isolated segments of jejunum from 12-week-old ob/ob and lean C57BL/6J (female and male mice. The basal Isc was significantly decreased (~30% in the ob/ob mice (66.5±5.7 µA/cm2 [n=20] (P< 0.05 compared with their lean counterparts (95.1±9.1 µA/cm2 [n=19]. Inhibition with clotrimazole (100 µM, applied bilaterally was significantly reduced in the ob/ob mice (−7.92%±3.67% [n=15] (P<0.05 compared with the lean mice (10.44%±7.92% [n=15], indicating a decreased contribution of Ca2+-activated K+ (KCa channels in the ob/ob mice. Inhibition with ouabain (100 µM, applied serosally was significantly reduced in the ob/ob mice (1.40%±3.61%, n=13 (P< 0.05 versus the lean mice (18.93%±3.76% [n=18], suggesting a potential defect in the Na+/K+-adenosine triphosphate (ATPase pump with leptin-deficiency. Expression of cystic fibrosis transmembrane conductance regulatory protein (CFTR (normalized to glyceraldehyde-3-phosphate dehydrogenase [GAPDH] was significantly decreased ~twofold (P<0.05 in the ob/ob mice compared with the leans, whilst crypt depth was unchanged. Villi length was significantly increased by ~25% (P<0.05 in the ob/ob mice compared with the leans and was associated with an increase in Villin and GLUT5 expression. GLUT2 and SGLT-1 expression were both unchanged. Our data suggests that reduced basal jejunal Isc in ob/ob mice is likely a consequence of

  14. Experimental evidence of a xylose-catabolic pathway on the pAO1 megaplasmid of Arthrobacter nicotinovorans

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    Marius Mihasan

    2012-09-01

    Full Text Available The pAO1 megaplasmid of A. nicotinovorans consists of 165 ORF's related mainly to nicotine degradation, uptake and utilization of carbohydrates, amino acids and sarcosine. A putative sugar catabolic pathway consisting of 11 ORF's organized as a single operon were previously described. The current work brings experimental data supporting the existence of a D-Xylose catabolic pathway on the pAO1 megaplasmid. When grown on D-xylose containing media, the cells harboring the pAO1 megaplasmid grow to higher cell densities and also express the OxRe protein coded by the megaplasmid. A putative pathway similar to Weimberg pentose pathway is postulated, in which D-xylose is transported in the cell by the ABC-type transport system and then transformed using the putative sugar-dehidrogenase OxRe to D-xylonate, which is further degrated to 2-ketoglutarate and integrated into the general metabolism of the cell

  15. A proteomic and transcriptomic view of amino acids catabolism in the yeast Yarrowia lipolytica.

    Science.gov (United States)

    Mansour, Soulaf; Bailly, Julie; Delettre, Jérôme; Bonnarme, Pascal

    2009-10-01

    The yeast Yarrowia lipolytica has to develop dynamic metabolic adaptation mechanisms to survive within the cheese habitat. The availability of amino acids (AAs) is of major importance for microbial development and/or aroma production during cheese ripening. Using 2-D protein gel electrophoresis, we analyzed the adaptation mechanisms of Y. lipolytica for AAs limitation or supplementation in a batch culture containing lactate as a carbon source. Proteome analyses allow the identification of 34 differentially expressed proteins between the culture conditions. These analyses demonstrated that prior to the AAs addition, mainly proteins involved in the oxidative stress of the yeast were induced. Following the AAs addition, yeast cells reorganize their metabolism toward AAs catabolism and also generate a higher induction of proteins related to carbon metabolism and proteins biosynthesis. Using real-time reverse transcription PCR, we re-evaluated the expression of genes encoding proteins involved in these processes. The expression levels of the genes were in accordance with the proteomic results, with the up-regulation of genes encoding a branched-chain amino transferase BAT2, a pyruvate decarboxylase PDC6 and an Hsp70 protein SSZ1 involved in protein biosynthesis. A volatile compound analysis was also performed, and increased production of dimethyldisulfide from methionine and 3-methyl-butanal from leucine was observed in media supplemented with AAs.

  16. Expression of the gonococcal global regulatory protein Fur and genes encompassing the Fur and iron regulon during in vitro and in vivo infection in women.

    Science.gov (United States)

    Agarwal, Sarika; Sebastian, Shite; Szmigielski, Borys; Rice, Peter A; Genco, Caroline A

    2008-05-01

    The ferric uptake regulatory protein, Fur, functions as a global regulatory protein of gene transcription in the mucosal pathogen Neisseria gonorrhoeae. We have shown previously that several N. gonorrhoeae Fur-repressed genes are expressed in vivo during mucosal gonococcal infection in men, which suggests that this organism infects in an iron-limited environment and that Fur is expressed under these conditions. In this study we have demonstrated expression of the gonococcal fur gene in vitro, in human cervical epithelial cells, and in specimens from female subjects with uncomplicated gonococcal infection. In vitro studies confirmed that the expression of the gonococcal fur gene was repressed during growth under iron-replete growth conditions but that a basal level of the protein was maintained. Using GFP transcriptional fusions constructed from specific Fur binding sequences within the fur promoter/operator region, we determined that this operator region was functional during N. gonorrhoeae infection of cervical epithelial cells. Furthermore, reverse transcription-PCR analysis, as well as microarray analysis, using a custom Neisseria Fur and iron regulon microarray revealed that several Fur- and iron-regulated genes were expressed during N. gonorrhoeae infection of cervical epithelial cells. Microarray analysis of specimens obtained from female subjects with uncomplicated gonococcal infection corroborated our in vitro findings and point toward a key role of gonococcal Fur- and iron-regulated genes in gonococcal disease.

  17. Amino acid catabolism by Lactobacillus helveticus in cheese

    DEFF Research Database (Denmark)

    Kananen, Soila Kaarina

    Amino acid catabolism is the final step in the conversion of caseins to flavour compounds and a part of a complex combination of biochemical pathways in cheese flavour formation. Lactobacillus helveticus is a thermophilic lactic acid bacterium that is used in cheese manufacture as a primary starter...... culture or as an adjunct culture. It has shown high proteolytic activities in conversion of caseins to peptides and further to amino acids and flavour compounds. Better understanding of the enzyme activity properties and the influence of different properties on final cheese flavour is favourable...... for developing new cheese products with enhanced flavour. The aim of this Ph.D. study was to investigate the importance of strain variation of Lb. helveticus in relation flavour formation in cheese related to amino acid catabolism. Aspects of using Lb. helveticus as starter as well as adjunct culture in cheese...

  18. Serine one-carbon catabolism with formate overflow

    Science.gov (United States)

    Meiser, Johannes; Tumanov, Sergey; Maddocks, Oliver; Labuschagne, Christiaan Fred; Athineos, Dimitris; Van Den Broek, Niels; Mackay, Gillian M.; Gottlieb, Eyal; Blyth, Karen; Vousden, Karen; Kamphorst, Jurre J.; Vazquez, Alexei

    2016-01-01

    Serine catabolism to glycine and a one-carbon unit has been linked to the anabolic requirements of proliferating mammalian cells. However, genome-scale modeling predicts a catabolic role with one-carbon release as formate. We experimentally prove that in cultured cancer cells and nontransformed fibroblasts, most of the serine-derived one-carbon units are released from cells as formate, and that formate release is dependent on mitochondrial reverse 10-CHO-THF synthetase activity. We also show that in cancer cells, formate release is coupled to mitochondrial complex I activity, whereas in nontransformed fibroblasts, it is partially insensitive to inhibition of complex I activity. We demonstrate that in mice, about 50% of plasma formate is derived from serine and that serine starvation or complex I inhibition reduces formate synthesis in vivo. These observations transform our understanding of one-carbon metabolism and have implications for the treatment of diabetes and cancer with complex I inhibitors.

  19. Neanderthal ancestry drives evolution of lipid catabolism in contemporary Europeans.

    Science.gov (United States)

    Khrameeva, Ekaterina E; Bozek, Katarzyna; He, Liu; Yan, Zheng; Jiang, Xi; Wei, Yuning; Tang, Kun; Gelfand, Mikhail S; Prufer, Kay; Kelso, Janet; Paabo, Svante; Giavalisco, Patrick; Lachmann, Michael; Khaitovich, Philipp

    2014-04-01

    Although Neanderthals are extinct, fragments of their genomes persist in contemporary humans. Here we show that while the genome-wide frequency of Neanderthal-like sites is approximately constant across all contemporary out-of-Africa populations, genes involved in lipid catabolism contain more than threefold excess of such sites in contemporary humans of European descent. Evolutionally, these genes show significant association with signatures of recent positive selection in the contemporary European, but not Asian or African populations. Functionally, the excess of Neanderthal-like sites in lipid catabolism genes can be linked with a greater divergence of lipid concentrations and enzyme expression levels within this pathway, seen in contemporary Europeans, but not in the other populations. We conclude that sequence variants that evolved in Neanderthals may have given a selective advantage to anatomically modern humans that settled in the same geographical areas.

  20. Ergosteryl-β-glucosidase (Egh1) involved in sterylglucoside catabolism and vacuole formation in Saccharomyces cerevisiae.

    Science.gov (United States)

    Watanabe, Takashi; Tani, Motohiro; Ishibashi, Yohei; Endo, Ikumi; Okino, Nozomu; Ito, Makoto

    2015-10-01

    Sterylglucosides (SGs) are composed of a glucose and sterol derivatives, and are distributed in fungi, plants and mammals. We recently identified EGCrP1 and EGCrP2 (endoglycoceramidase-related proteins 1 and 2) as a β-glucocerebrosidase and steryl-β-glucosidase, respectively, in Cryptococcus neoformans. We herein describe an EGCrP2 homologue (Egh1; ORF name, Yir007w) involved in SG catabolism in Saccharomyces cerevisiae. The purified recombinant Egh1 hydrolyzed various β-glucosides including ergosteryl β-glucoside (EG), cholesteryl β-glucoside, sitosteryl β-glucoside, para-nitrophenyl β-glucoside, 4-methylumberifellyl β-glucoside and glucosylceramide. The disruption of EGH1 in S. cerevisiae BY4741 (egh1Δ) resulted in the accumulation of EG and fragmentation of vacuoles. The expression of EGH1 in egh1Δ (revertant) reduced the accumulation of EG, and restored the morphology of vacuoles. The accumulation of EG was not detected in EGH1 and UGT51(ATG26) double-disrupted mutants (ugt51Δegh1Δ), indicating that EG was synthesized by Ugt51(Atg26) and degraded by Egh1 in vivo. These results clearly demonstrated that Egh1 is an ergosteryl-β-glucosidase that is functionally involved in the EG catabolic pathway and vacuole formation in S. cerevisiae.

  1. Bleached Porites compressa and Montipora capitata corals catabolize δ13C-enriched lipids

    Science.gov (United States)

    Grottoli, Andréa G.; Rodrigues, Lisa J.

    2011-09-01

    Corals rely on stored energy reserves (i.e., lipids, carbohydrates, and protein) to survive bleaching events. To better understand the physiological implications of coral bleaching on lipid catabolism and/or synthesis, we measured the δ13C of coral total lipids (δ13CTL) in experimentally bleached (treatment) and non-bleached (control) Porites compressa and Montipora capitata corals immediately after bleaching and after 1.5 and 4 months of recovery on the reef. Overall δ13CTL values in treatment corals were significantly lower than in control corals because of a 1.9 and 3.4‰ decrease in δ13CTL immediately after bleaching in P. compressa and M. capitata, respectively. The decrease in δ13CTL coincided with decreases in total lipid concentration, indicating that corals catabolized δ13C-enriched lipids. Since storage lipids are primarily depleted during bleaching, we hypothesize that they are isotopically enriched relative to other lipid classes. This work further helps clarify our understanding of changes to coral metabolism and biogeochemistry when bleached and helps elucidate how lipid classes may influence recovery from bleaching and ultimately coral survival.

  2. Mediated Electrochemical Measurements of Intracellular Catabolic Activities of Yeast Cells

    Institute of Scientific and Technical Information of China (English)

    Jin Sheng ZHAO; Zhen Yu YANG; Yao LU; Zheng Yu YANG

    2005-01-01

    Coupling with the dual mediator system menadione/ferricyanide, microelectrode voltammetric measurements were undertaken to detect the ferrocyanide accumulations arising from the mediated reduction of ferricyanide by yeast cells. The results indicate that the dual mediator system menadione/ferricyanide could be used as a probe to detect cellular catabolic activities in yeast cells and the electrochemical response has a positive relationship with the specific growth rate of yeast cells.

  3. Threshold Acetate Concentrations for Acetate Catabolism by Aceticlastic Methanogenic Bacteria

    OpenAIRE

    Westermann, Peter; Ahring, Birgitte K.; Mah, Robert A.

    1989-01-01

    Marked differences were found for minimum threshold concentrations of acetate catabolism by Methanosarcina barkeri 227 (1.180 mM), Methanosarcina mazei S-6 (0.396 mM), and a Methanothrix sp. (0.069 mM). This indicates that the aceticlastic methanogens responsible for the conversion of acetate to methane in various ecosystems might be different, depending on the prevailing in situ acetate concentrations.

  4. Genetic and metabolic analysis of the carbofuran catabolic pathway in Novosphingobium sp. KN65.2.

    Science.gov (United States)

    Nguyen, Thi Phi Oanh; Helbling, Damian E; Bers, Karolien; Fida, Tekle Tafese; Wattiez, Ruddy; Kohler, Hans-Peter E; Springael, Dirk; De Mot, René

    2014-10-01

    The widespread agricultural application of carbofuran and concomitant contamination of surface and ground waters has raised health concerns due to the reported toxic effects of this insecticide and its degradation products. Most bacteria that degrade carbofuran only perform partial degradation involving carbamate hydrolysis without breakdown of the resulting phenolic metabolite. The capacity to mineralize carbofuran beyond the benzofuran ring has been reported for some bacterial strains, especially sphingomonads, and some common metabolites, including carbofuran phenol, were identified. In the current study, the catabolism of carbofuran by Novosphingobium sp. KN65.2 (LMG 28221), a strain isolated from a carbofuran-exposed Vietnamese soil and utilizing the compound as a sole carbon and nitrogen source, was studied. Several KN65.2 plasposon mutants with diminished or abolished capacity to degrade and mineralize carbofuran were generated and characterized. Metabolic profiling of representative mutants revealed new metabolic intermediates, in addition to the initial hydrolysis product carbofuran phenol. The promiscuous carbofuran-hydrolyzing enzyme Mcd, which is present in several bacteria lacking carbofuran ring mineralization capacity, is not encoded by the Novosphingobium sp. KN65.2 genome. An alternative hydrolase gene required for this step was not identified, but the constitutively expressed genes of the unique cfd operon, including the oxygenase genes cfdC and cfdE, could be linked to further degradation of the phenolic metabolite. A third involved oxygenase gene, cfdI, and the transporter gene cftA, encoding a TonB-dependent outer membrane receptor with potential regulatory function, are located outside the cfd cluster. This study has revealed the first dedicated carbofuran catabolic genes and provides insight in the early steps of benzofuran ring degradation.

  5. Human chorionic gonadotropin (hCG) regulates the expression of Steroidogenic acute regulatory protein (STAR)via the ERK1/2 pathway

    Institute of Scientific and Technical Information of China (English)

    WANG Xianzhong; SUN Yan; WU Jianyun; PAN Hongmei; ZHANG Jiahua

    2007-01-01

    It has previously been shown that Human Chorionic Gonadotropin (hCG) can stimulate steroidogenesis in Leydig cells.In the present study,the mechanisms of hCGstimulated steroidogenesis in Leydig cells of immaturated pigs were investigated.It was found that both hCG and 8Br-cAMP could enhance the expression level of both the Steroidogenic acute regulatory protein (STAR) and mRNA,and increase the activity of extracellular signal-regulated kinasel/2 (ERK1/2) significantly depending on stimulating time.However,the effect of 8-Br-cAMP was more significant than that of hCG.While appending the inhibitor of Protein Kinase A (PKA) to Leydig cells in culture,the expression level of StAR protein,mRNA and the activity of ERK1/2 began to drop significantly,but the level of StAR mRNA could still be detectable.While appending the inhibitor of MAPK (PD98059),the expression level of StAR protein and mRNA declined significantly.These results infer that at the beginning of hCG stimulation,hCG increases the level of StAR protein by cAMP-PKA.With prolonged stimulating time,hCG increases the level of StAR protein through cAMP-PKA-ERK1/2.

  6. Geochemical Energy for Catabolism and Anabolism in Hydrothermal Systems

    Science.gov (United States)

    Amend, J. P.; McCollom, T. M.; Bach, W.

    2008-12-01

    Chemically reduced deep-sea vent fluids mixed with oxidized seawater can generate redox disequilibria that serve as energy sources for chemolithoautotrophic (catabolism) and biomass synthesis (anabolism) reactions. Numerical models can be used to evaluate Gibbs energies of such processes on the early Earth and in present-day systems. Here, geochemical data from compositionally diverse vent fluids (Lost City, Rainbow, Logatchev, TAG, 21 °N EPR) are combined with several seawater chemistries to yield a wide range of mixed hydrothermal solutions; this is the starting point for our thermodynamic calculations. In ultramafic-hosted hydrothermal systems, such as Rainbow or Lost City, aerobic chemolithotrophic catabolisms (oxidation of H2, FeII, CH4) are the most energy-yielding at low temperatures (catabolic reaction energetics can then be used to put constraints on the amount of primary biomass production. Under putative early Earth conditions, for example, the net chemoautotrophic synthesis of cellular building blocks is thermodynamically most favorable at moderate temperatures (~50°C), where the energy contributions from HCO3- and H+ in cool seawater coupled to the reducing power in hot vent fluid are optimized. At these conditions, and counter to conventional wisdom, the synthesis of amino acids may even yield small amounts of energy.

  7. Expanding the archaellum regulatory network - the eukaryotic protein kinases ArnC and ArnD influence motility of Sulfolobus acidocaldarius.

    Science.gov (United States)

    Hoffmann, Lena; Schummer, Andreas; Reimann, Julia; Haurat, Maria F; Wilson, Amanda J; Beeby, Morgan; Warscheid, Bettina; Albers, Sonja-V

    2017-02-01

    Expression of the archaellum, the archaeal-type IV pilus-like rotating motility structure is upregulated under nutrient limitation. This is controlled by a network of regulators, called the archaellum regulatory network (arn). Several of the components of this network in Sulfolobus acidocaldarius can be phosphorylated, and the deletion of the phosphatase PP2A results in strongly increased motility during starvation, indicating a role for phosphorylation in the regulation of motility. Analysis of the motility of different protein kinase deletion strains revealed that deletion of saci_0965, saci_1181, and saci_1193 resulted in reduced motility, whereas the deletion of saci_1694 resulted in hypermotility. Here ArnC (Saci_1193) and ArnD (Saci_1694) are characterized. Purified ArnC and ArnD phosphorylate serine and threonine residues in the C-terminus of the repressor ArnB. arnC is upregulated in starvation medium, whereas arnD is constitutively expressed. However, while differences in the expression and levels of flaB were observed in the ΔarnD strain during growth under rich conditions, under nutrient limiting conditions the ΔarnC and ΔarnD strains showed no large differences in the expression levels of the archaellum or of the studied regulators. This suggests that next to the regulation via the archaellum regulatory network additional regulatory mechanisms of expression and/or activity of the archaellum exist.

  8. The vasa regulatory region mediates germline expression and maternal transmission of proteins in the malaria mosquito Anopheles gambiae: a versatile tool for genetic control strategies

    Directory of Open Access Journals (Sweden)

    Burt Austin

    2009-07-01

    Full Text Available Abstract Background Germline specific promoters are an essential component of potential vector control strategies which function by genetic drive, however suitable promoters are not currently available for the main human malaria vector Anopheles gambiae. Results We have identified the Anopheles gambiae vasa-like gene and found its expression to be specifically localized to both the male and female gonads in adult mosquitoes. We have functionally characterised using transgenic reporter lines the regulatory regions required for driving transgene expression in a pattern mirroring that of the endogenous vasa locus. Two reporter constructs indicate the existence of distinct vasa regulatory elements within the 5' untranslated regions responsible not only for the spatial and temporal but also for the sex specific germline expression. vasa driven eGFP expression in the ovary of heterozygous mosquitoes resulted in the progressive accumulation of maternal protein and transcript in developing oocytes that were then detectable in all embryos and neonatal larvae. Conclusion We have characterized the vasa regulatory regions that are not only suited to drive transgenes in the early germline of both sexes but could also be utilized to manipulate the zygotic genome of developing embryos via maternal deposition of active molecules. We have used computational models to show that a homing endonuclease-based gene drive system can function in the presence of maternal deposition and describe a novel non-invasive control strategy based on early vasa driven homing endonuclease expression.

  9. Preventing phosphorylation of sterol regulatory element-binding protein 1a by MAP-kinases protects mice from fatty liver and visceral obesity.

    Science.gov (United States)

    Kotzka, Jorg; Knebel, Birgit; Haas, Jutta; Kremer, Lorena; Jacob, Sylvia; Hartwig, Sonja; Nitzgen, Ulrike; Muller-Wieland, Dirk

    2012-01-01

    The transcription factor sterol regulatory element binding protein (SREBP)-1a plays a pivotal role in lipid metabolism. Using the SREBP-1a expressing human hepatoma cell line HepG2 we have shown previously that human SREBP-1a is phosphorylated at serine 117 by ERK-mitogen-activated protein kinases (MAPK). Using a combination of cell biology and protein chemistry approach we show that SREBP-1a is also target of other MAPK-families, i.e. c-JUN N-terminal protein kinases (JNK) or p38 stress activated MAP kinases. Serine 117 is also the major phosphorylation site in SREBP-1a for JNK. In contrast to that the major phosphorylation sites of p38 MAPK family are serine 63 and threonine 426. Functional analyses reveal that phosphorylation of SREBP-1a does not alter protein/DNA interaction. The identified phosphorylation sites are specific for both kinase families also in cellular context. To provide direct evidence that phosphorylation of SREBP-1a is a regulatory principle of biological and clinical relevance, we generated transgenic mice expressing mature transcriptionally active N-terminal domain of human SREBP-1a variant lacking all identified phosphorylaton sites designed as alb-SREBP-1aΔP and wild type SREBP-1a designed as alb-SREBP-1a liver specific under control of the albumin promoter and a liver specific enhancer. In contrast to alb-SREBP-1a mice the phosphorylation-deficient mice develop no enlarged fatty livers under normocaloric conditions. Phenotypical examination reveales a massive accumulation of adipose tissue in alb-SREBP-1a but not in the phosphorylation deficient alb-SREBP-1aΔP mice. Moreover, preventing phosphorylation of SREBP-1a protects mice also from dyslipidemia. In conclusion, phosphorylation of SREBP-1a by ERK, JNK and p38 MAPK-families resembles a biological principle and plays a significant role, in vivo.

  10. Preventing phosphorylation of sterol regulatory element-binding protein 1a by MAP-kinases protects mice from fatty liver and visceral obesity.

    Directory of Open Access Journals (Sweden)

    Jorg Kotzka

    Full Text Available The transcription factor sterol regulatory element binding protein (SREBP-1a plays a pivotal role in lipid metabolism. Using the SREBP-1a expressing human hepatoma cell line HepG2 we have shown previously that human SREBP-1a is phosphorylated at serine 117 by ERK-mitogen-activated protein kinases (MAPK. Using a combination of cell biology and protein chemistry approach we show that SREBP-1a is also target of other MAPK-families, i.e. c-JUN N-terminal protein kinases (JNK or p38 stress activated MAP kinases. Serine 117 is also the major phosphorylation site in SREBP-1a for JNK. In contrast to that the major phosphorylation sites of p38 MAPK family are serine 63 and threonine 426. Functional analyses reveal that phosphorylation of SREBP-1a does not alter protein/DNA interaction. The identified phosphorylation sites are specific for both kinase families also in cellular context. To provide direct evidence that phosphorylation of SREBP-1a is a regulatory principle of biological and clinical relevance, we generated transgenic mice expressing mature transcriptionally active N-terminal domain of human SREBP-1a variant lacking all identified phosphorylaton sites designed as alb-SREBP-1aΔP and wild type SREBP-1a designed as alb-SREBP-1a liver specific under control of the albumin promoter and a liver specific enhancer. In contrast to alb-SREBP-1a mice the phosphorylation-deficient mice develop no enlarged fatty livers under normocaloric conditions. Phenotypical examination reveales a massive accumulation of adipose tissue in alb-SREBP-1a but not in the phosphorylation deficient alb-SREBP-1aΔP mice. Moreover, preventing phosphorylation of SREBP-1a protects mice also from dyslipidemia. In conclusion, phosphorylation of SREBP-1a by ERK, JNK and p38 MAPK-families resembles a biological principle and plays a significant role, in vivo.

  11. NahY, a Catabolic Plasmid-Encoded Receptor Required for Chemotaxis of Pseudomonas putida to the Aromatic Hydrocarbon Naphthalene

    OpenAIRE

    1999-01-01

    Pseudomonas putida G7 exhibits chemotaxis to naphthalene, but the molecular basis for this was not known. A new gene, nahY, was found to be cotranscribed with meta cleavage pathway genes on the NAH7 catabolic plasmid for naphthalene degradation. The nahY gene encodes a 538-amino-acid protein with a membrane topology and a C-terminal region that resemble those of chemotaxis transducer proteins. A P. putida G7 nahY mutant grew on naphthalene but was not chemotactic to this aromatic hydrocarbon....

  12. Responsibility of regulatory gene expression and repressed protein synthesis for triacylglycerol accumulation on sulfur-starvation in Chlamydomonas reinhardtii

    OpenAIRE

    2014-01-01

    Triacylglycerol (TG) synthesis is induced for energy and carbon storage in algal cells under nitrogen(N)-starved conditions, and helps prevent reactive oxygen species (ROS) production through fatty acid synthesis that consumes excessive reducing power. Here, the regulatory mechanism for the TG content in sulfur(S)-starved cells of Chlamydomonas reinhardtii was examined, in comparison to that in N- or phosphorus(P)-starved cells. S- and N- starved cells exhibited markedly increased TG contents...

  13. Levels of Regulatory Proteins Associated With Cell Proliferation in Endometria From Untreated Patients Having Polycystic Ovarian Syndrome With and Without Endometrial Hyperplasia.

    Science.gov (United States)

    Bacallao, K; Plaza-Parrochia, F; Cerda, A; Gabler, F; Romero, C; Vantman, D; Vega, M

    2016-02-01

    Polycystic ovarian syndrome (PCOS) has been associated with endometrial hyperplasia and cancer. The aim of this study was to establish whether the expression of proliferation regulatory proteins in the endometria of patients having PCOS, with or without hyperplasia, differs from control women. Control endometria (CE), patients having PCOS without and with endometrial hyperplasia (PCOSE and HPCOSE, respectively), and that of women with endometrial hyperplasia (HE) were used. The phosphorylated estrogen receptor form (pERα), similar to mother against decapentaplegic (SMAD) 2, SMAD3, and SMAD4, vascular epithelial growth factor (VEGF), and phosphorylated SMAD (pSMAD) 2 and pSMAD3 were detected by immunohistochemistry or Western blot. The results show higher levels of pERα in HE versus CE (P hyperplasia and cancer, whereas changes observed in SMAD proteins support the differential origin of the pathologies of HPCOSE and HE.

  14. Lysosomal-associated Transmembrane Protein 4B (LAPTM4B) Decreases Transforming Growth Factor β1 (TGF-β1) Production in Human Regulatory T Cells.

    Science.gov (United States)

    Huygens, Caroline; Liénart, Stéphanie; Dedobbeleer, Olivier; Stockis, Julie; Gauthy, Emilie; Coulie, Pierre G; Lucas, Sophie

    2015-08-14

    Production of active TGF-β1 is one mechanism by which human regulatory T cells (Tregs) suppress immune responses. This production is regulated by glycoprotein A repetitions predominant (GARP), a transmembrane protein present on stimulated Tregs but not on other T lymphocytes (Th and CTLs). GARP forms disulfide bonds with proTGF-β1, favors its cleavage into latent inactive TGF-β1, induces the secretion and surface presentation of GARP·latent TGF-β1 complexes, and is required for activation of the cytokine in Tregs. We explored whether additional Treg-specific protein(s) associated with GARP·TGF-β1 complexes regulate TGF-β1 production in Tregs. We searched for such proteins by yeast two-hybrid assay, using GARP as a bait to screen a human Treg cDNA library. We identified lysosomal-associated transmembrane protein 4B (LAPTM4B), which interacts with GARP in mammalian cells and is expressed at higher levels in Tregs than in Th cells. LAPTM4B decreases cleavage of proTGF-β1, secretion of soluble latent TGF-β1, and surface presentation of GARP·TGF-β1 complexes by Tregs but does not contribute to TGF-β1 activation. Therefore, LAPTM4B binds to GARP and is a negative regulator of TGF-β1 production in human Tregs. It may play a role in the control of immune responses by decreasing Treg immunosuppression.

  15. Magnolol causes alterations in the cell cycle in androgen insensitive human prostate cancer cells in vitro by affecting expression of key cell cycle regulatory proteins.

    Science.gov (United States)

    McKeown, Brendan T; McDougall, Luke; Catalli, Adriana; Hurta, Robert A R

    2014-01-01

    Prostate cancer, one of the most common cancers in the Western world, affects many men worldwide. This study investigated the effects of magnolol, a compound found in the roots and bark of the magnolia tree Magnolia officinalis, on the behavior of 2 androgen insensitive human prostate cancer cell lines, DU145 and PC3, in vitro. Magnolol, in a 24-h exposure at 40 and 80 μM, was found to be cytotoxic to cells. Magnolol also affected cell cycle progression of DU145 and PC3 cells, resulting in alterations to the cell cycle and subsequently decreasing the proportion of cells entering the G2/M-phase of the cell cycle. Magnolol inhibited the expression of cell cycle regulatory proteins including cyclins A, B1, D1, and E, as well as CDK2 and CDK4. Protein expression levels of pRBp107 decreased and pRBp130 protein expression levels increased in response to magnolol exposure, whereas p16(INK4a), p21, and p27 protein expression levels were apparently unchanged post 24-h exposure. Magnolol exposure at 6 h did increase p27 protein expression levels. This study has demonstrated that magnolol can alter the behavior of androgen insensitive human prostate cancer cells in vitro and suggests that magnolol may have potential as a novel anti-prostate cancer agent.

  16. Inhibitory Effects of NO-Fluvastatin on Proliferation of Human Lens Epithelial Cells in vitro by Modulating Cell Cycle Regulatory Proteins

    Institute of Scientific and Technical Information of China (English)

    Zhi WANG; Ruiying GAO; Qianqian SHI; Yukan HUANG; Wen CHEN; Kaiying SHI

    2008-01-01

    Summary: The effects of NO-Fluvastatin on proliferation of human lens epithelial cells (HLECs) and the action mechanism were investigated. Cell proliferation was assessed by MTT assay. Cell cycle was analyzed by flow cytometry. The expression of cell cycle regulatory proteins CyclinE mRNA and P21wafl mRNA was detected by reverse transcription polymerase chain reaction (RT-PCR). MTT staining colorimetry showed that HLECs proliferation was markedly inhibited by NO-Fluvastatin and the effect was dependently related to time (24, 48 and 72 h) and dosage (1, 5 and 20 μmol/L). Flow cytometry revealed that NO-Fluvastatin could significantly block HLECs in the G0/G1 phase, resulting in the increased cells in the G0G1 phase and decreased in the S phase (P<0.05). RT-PCR showed that NO-Fluvastatin could obviously inhibit the CyclinE mRNA expression and induce the P21wafl mRNA expression as compared with the negative control groups (P<0.05). This experiment suggested that NO-Fluvastatin could suppress the proliferation of HLECs by regulating cell cycle regulatory proteins (inhibiting the expression of CyclinE mRNA and inducing the expression of P21wafl mRNA), resulting in the arrest of HLECs in the G0/G1 phase, which can offer theory basis for NO-Fluvastatin in treating posterior capsular opacification in clinic practice.

  17. Variations at regulatory regions of the milk protein genes are associated with milk traits and coagulation properties in the Sarda sheep.

    Science.gov (United States)

    Noce, A; Pazzola, M; Dettori, M L; Amills, M; Castelló, A; Cecchinato, A; Bittante, G; Vacca, G M

    2016-12-01

    Regulatory variation at the ovine casein genes could have important effects on the composition and coagulation properties of milk. Herewith, we have partially resequenced the promoters and the 3'-UTR of the four casein genes in 25 Sarda sheep. Alignment of these sequences allowed us to identify a total of 29 SNPs. This level of polymorphism (one SNP every 250 bp) is remarkably high if compared with SNP densities estimated in human genic regions (approximately one SNP per bp). The 29 SNPs identified in our resequencing experiment, plus three previously reported SNPs mapping to the lactalbumin, alpha (LALBA) and β-lactoglobulin (BLG, also known as progestagen-associated endometrial protein, PAEP) genes, were genotyped with a multiplex TaqMan Open Array Real-Time PCR assay in 760 Sarda sheep with records for milk composition and coagulation properties. Association analysis revealed the existence of significant associations of CSN1S2 and CSN3 genotypes with milk protein and casein contents. Moreover, genotypes at CSN1S1 were significantly associated with rennet coagulation time, curd firming time and curd firmness, whereas CSN2 was associated with curd firming time. These results suggest that SNPs mapping to the promoters and 3'-UTRs of ovine casein genes may exert regulatory effects on gene expression and that they could be used for improving sheep milk quality and technological traits at the population level through marker assisted selection.

  18. Aging is Associated with Impaired Renal Function, INF-gamma Induced Inflammation and with Alterations in Iron Regulatory Proteins Gene Expression

    Science.gov (United States)

    Costa, Elísio; Fernandes, João; Ribeiro, Sandra; Sereno, José; Garrido, Patrícia; Rocha-Pereira, Petronila; Coimbra, Susana; Catarino, Cristina; Belo, Luís; Bronze-da-Rocha, Elsa; Vala, Helena; Alves, Rui; Reis, Flávio; Santos-Silva, Alice

    2014-01-01

    Our aim was to contribute to a better understanding of the pathophysiology of anemia in elderly, by studying how aging affects renal function, iron metabolism, erythropoiesis and the inflammatory response, using an experimental animal model. The study was performed in male Wistar, a group of young rats with 2 months age and an old one with 18 months age. Old rats presented a significant higher urea, creatinine, interferon (INF)-gamma, ferritin and soluble transferrin receptor serum levels, as well as increased counts of reticulocytes and RDW. In addition, these rats showed significant lower erythropoietin (EPO) and iron serum levels. Concerning gene expression of iron regulatory proteins, old rats presented significantly higher mRNA levels of hepcidin (Hamp), transferrin (TF), transferrin receptor 2 (TfR2) and hemojuvelin (HJV); divalent metal transporter 1 (DMT1) mRNA levels were significantly higher in duodenal tissue; EPO gene expression was significantly higher in liver and lower in kidney, and the expression of the EPOR was significantly higher in both liver and kidney. Our results showed that aging is associated with impaired renal function, which could be in turn related with the inflammatory process and with a decline in EPO renal production. Moreover, we also propose that aging may be associated with INF-gamma-induced inflammation and with alterations upon iron regulatory proteins gene expression. PMID:25489488

  19. Increased HDL Size and Enhanced Apo A-I Catabolic Rates Are Associated With Doxorubicin-Induced Proteinuria in New Zealand White Rabbits.

    Science.gov (United States)

    López-Olmos, Victoria; Carreón-Torres, Elizabeth; Luna-Luna, María; Flores-Castillo, Cristobal; Martínez-Ramírez, Miriam; Bautista-Pérez, Rocío; Franco, Martha; Sandoval-Zárate, Julio; Roldán, Francisco-Javier; Aranda-Fraustro, Alberto; Soria-Castro, Elizabeth; Muñoz-Vega, Mónica; Fragoso, José-Manuel; Vargas-Alarcón, Gilberto; Pérez-Méndez, Oscar

    2016-03-01

    The catabolism and structure of high-density lipoproteins (HDL) may be the determining factor of their atheroprotective properties. To better understand the role of the kidney in HDL catabolism, here we characterized HDL subclasses and the catabolic rates of apo A-I in a rabbit model of proteinuria. Proteinuria was induced by intravenous administration of doxorubicin in New Zealand white rabbits (n = 10). HDL size and HDL subclass lipids were assessed by electrophoresis of the isolated lipoproteins. The catabolic rate of HDL-apo A-I was evaluated by exogenous radiolabelling with iodine-131. Doxorubicin induced significant proteinuria after 4 weeks (4.47 ± 0.55 vs. 0.30 ± 0.02 g/L of protein in urine, P HDL2b augmented significantly during proteinuria, whereas small HDL3b and HDL3c decreased compared to basal conditions. HDL2b, HDL2a, and HDL3a subclasses were enriched with triacylglycerols in proteinuric animals as determined by the triacylglycerol-to-phospholipid ratio; the cholesterol content in HDL subclasses remained unchanged. The fractional catabolic rate (FCR) of [(131)I]-apo A-I in the proteinuric rabbits was faster (FCR = 0.036 h(-1)) compared to control rabbits group (FCR = 0.026 h(-1), P HDL, whereas PON-1 activity increased in proteinuric rabbits. Proteinuria was associated with an increased number of large HDL2b particles and a decreased number of small HDL3b and 3c. Proteinuria was also connected to an alteration in HDL subclass lipids, apolipoprotein content of HDL, high paraoxonase-1 activity, and a rise in the fractional catabolic rate of the [(131)I]-apo A-I.

  20. Increased expression and purification of soluble iron-regulatory protein 1 from Escherichia coli co-expressing chaperonins GroES and GroEL

    Directory of Open Access Journals (Sweden)

    H. Carvalho

    2008-04-01

    Full Text Available Iron is an essential metal for all living organisms. However, iron homeostasis needs to be tightly controlled since iron can mediate the production of reactive oxygen species, which can damage cell components and compromise the integrity and/or cause DNA mutations, ultimately leading to cancer. In eukaryotes, iron-regulatory protein 1 (IRP1 plays a central role in the control of intracellular iron homeostasis. This occurs by interaction of IRP1 with iron-responsive element regions at 5' of ferritin mRNA and 3' of transferrin mRNA which, respectively, represses translation and increases mRNA stability. We have expressed IRP1 using the plasmid pT7-His-hIRP1, which codifies for human IRP1 attached to an NH2-terminal 6-His tag. IRP1 was expressed in Escherichia coli using the strategy of co-expressing chaperonins GroES and GroEL, in order to circumvent inclusion body formation and increase the yield of soluble protein. The protein co-expressed with these chaperonins was obtained mostly in the soluble form, which greatly increased the efficiency of protein purification. Metal affinity and FPLC ion exchange chromatography were used in order to obtain highly purified IRP1. Purified protein was biologically active, as assessed by electrophoretic mobility shift assay, and could be converted to the cytoplasmic aconitase form. These results corroborate previous studies, which suggest the use of folding catalysts as a powerful strategy to increase protein solubility when expressing heterologous proteins in E. coli.

  1. Overexpression, purification, crystallization and preliminary structural studies of catabolic ornithine transcarbamylase from Lactobacillus hilgardii

    Energy Technology Data Exchange (ETDEWEB)

    Rivas, Blanca de las; Rodríguez, Héctor [Instituto de Fermentaciones Industriales, CSIC, Juan de la Cierva 3, 28006 Madrid (Spain); Angulo, Iván [Grupo de Cristalografía Macromolecular y Biología Estructural, Instituto Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain); Muñoz, Rosario [Instituto de Fermentaciones Industriales, CSIC, Juan de la Cierva 3, 28006 Madrid (Spain); Mancheño, José M., E-mail: xjosemi@iqfr.csic.es [Grupo de Cristalografía Macromolecular y Biología Estructural, Instituto Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain); Instituto de Fermentaciones Industriales, CSIC, Juan de la Cierva 3, 28006 Madrid (Spain)

    2007-07-01

    The catabolic ornithine transcarbamylase (cOTC) from L. hilgardii has been overexpressed in E. coli, purified and crystallized under two different experimental conditions. The structure has been solved by the molecular-replacement method using the atomic coordinates of catabolic ornithine transcarbamylase from P. aeruginosa as the search model. The catabolic ornithine transcarbamylase (cOTC; EC 2.1.3.3) from the lactic acid bacteria Lactobacillus hilgardii is a key protein involved in the degradation of arginine during malolactic fermentation. cOTC containing an N-terminal His{sub 6} tag has been overexpressed in Escherichia coli, purified and crystallized under two different experimental conditions using the hanging-drop vapour-diffusion method. Crystals obtained from a solution containing 8%(w/v) PEG 4000, 75 mM sodium acetate pH 4.6 belong to the trigonal space group P321 and have unit-cell parameters a = b = 157.04, c = 79.28 Å. Conversely, crystals grown in 20%(v/v) 2-methyl-2,4-pentanediol, 7.5%(w/v) PEG 4000, 100 mM HEPES pH 7.8 belong to the monoclinic space group C2 and have unit-cell parameters a = 80.06, b = 148.90, c = 91.67 Å, β = 100.25°. Diffraction data were collected in-house to 3.00 and 2.91 Å resolution for trigonal and monoclinic crystals, respectively. The estimated Matthews coefficient for the crystal forms were 2.36 and 2.24 Å{sup 3} Da{sup −1}, respectively, corresponding to 48% and 45% solvent content. In both cases, the results are consistent with the presence of three protein subunits in the asymmetric unit. The structure of cOTC has been determined by the molecular-replacement method using the atomic coordinates of cOTC from Pseudomonas aeruginosa (PDB code) as the search model.

  2. Phylogenetic divergence of CD47 interactions with human signal regulatory protein alpha reveals locus of species specificity. Implications for the binding site.

    Science.gov (United States)

    Subramanian, Shyamsundar; Boder, Eric T; Discher, Dennis E

    2007-01-19

    Cell-cell interactions between ubiquitously expressed integrin-associated protein (CD47) and its counterreceptor signal regulatory protein (SIRPalpha) on phagocytes regulate a wide range of adhesive signaling processes, including the inhibition of phagocytosis as documented in mice. We show that CD47-SIRPalpha binding interactions are different between mice and humans, and we exploit phylogenetic divergence to identify the species-specific binding locus on the immunoglobulin domain of human CD47. All of the studies are conducted in the physiological context of membrane protein display on Chinese hamster ovary (CHO) cells. Novel quantitative flow cytometry analyses with CD47-green fluorescent protein and soluble human SIRPalpha as a probe show that neither human CD47 nor SIRPalpha requires glycosylation for interaction. Human CD47-expressing CHO cells spread rapidly on SIRPalpha-coated glass surfaces, correlating well with the spreading of primary human T cells. In contrast, CHO cells expressing mouse CD47 spread minimally and show equally weak binding to soluble human SIRPalpha. Further phylogenetic analyses and multisite substitutions of the CD47 Ig domain show that human to cow mutation of a cluster of seven residues on adjacent strands near the middle of the domain decreases the association constant for human SIRPalpha to about one-third that of human CD47. Direct tests of cell-cell adhesion between human monocytes and CD47-displaying CHO cells affirm the species specificity as well as the importance of the newly identified binding locus in cell-cell interactions.

  3. Interaction between glutamate dehydrogenase (GDH) and L-leucine catabolic enzymes: intersecting metabolic pathways.

    Science.gov (United States)

    Hutson, Susan M; Islam, Mohammad Mainul; Zaganas, Ioannis

    2011-09-01

    Branched-chain amino acids (BCAAs) catabolism follows sequential reactions and their metabolites intersect with other metabolic pathways. The initial enzymes in BCAA metabolism, the mitochondrial branched-chain aminotransferase (BCATm), which deaminates the BCAAs to branched-chain α-keto acids (BCKAs); and the branched-chain α-keto acid dehydrogenase enzyme complex (BCKDC), which oxidatively decarboxylates the BCKAs, are organized in a supramolecular complex termed metabolon. Glutamate dehydrogenase (GDH1) is found in the metabolon in rat tissues. Bovine GDH1 binds to the pyridoxamine 5'-phosphate (PMP)-form of human BCATm (PMP-BCATm) but not to pyridoxal 5'-phosphate (PLP)-BCATm in vitro. This protein interaction facilitates reamination of the α-ketoglutarate (αKG) product of the GDH1 oxidative deamination reaction. Human GDH1 appears to act like bovine GDH1 but human GDH2 does not show the same enhancement of BCKDC enzyme activities. Another metabolic enzyme is also found in the metabolon is pyruvate carboxylase (PC). Kinetic results suggest that PC binds to the E1 decarboxylase of BCKDC but does not effect BCAA catabolism. The protein interaction of BCATm and GDH1 promotes regeneration of PLP-BCATm which then binds to BCKDC resulting in channeling of the BCKA products from BCATm first half reaction to E1 and promoting BCAA oxidation and net nitrogen transfer from BCAAs. The cycling of nitrogen through glutamate via the actions of BCATm and GDH1 releases free ammonia. Formation of ammonia may be important for astrocyte glutamine synthesis in the central nervous system. In peripheral tissue association of BCATm and GDH1 would promote BCAA oxidation at physiologically relevant BCAA concentrations.

  4. Signal peptide cleavage is essential for surface expression of a regulatory T cell surface protein, leucine rich repeat containing 32 (LRRC32

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    Sugiyama Hideaki

    2011-05-01

    Full Text Available Abstract Background Elevated numbers of regulatory T cells (Tregs have been implicated in certain cancers. Depletion of Tregs has been shown to increase anti-tumor immunity. Tregs also play a critical role in the suppression of autoimmune responses. The study of Tregs has been hampered by a lack of adequate surface markers. Leucine Rich Repeat Containing 32 (LRRC32, also known as Glycoprotein A Repetitions Predominant (GARP, has been postulated as a novel surface marker of activated Tregs. However, there is limited information regarding the processing of LRRC32 or the regulatory phenotype and functional activity of Tregs expressing LRRC32. Results Using naturally-occurring freshly isolated Tregs, we demonstrate that low levels of LRRC32 are present intracellularly prior to activation and that freshly isolated LRRC32+ Tregs are distinct from LRRC32- Tregs with respect to the expression of surface CD62L. Using LRRC32 transfectants of HEK cells, we demonstrate that the N-terminus of LRRC32 is cleaved prior to expression of the protein at the cell surface. Furthermore, we demonstrate using a construct containing a deleted putative signal peptide region that the presence of a signal peptide region is critical to cell surface expression of LRRC32. Finally, mixed lymphocyte assays demonstrate that LRRC32+ Tregs are more potent suppressors than LRRC32- Tregs. Conclusions A cleaved signal peptide site in LRRC32 is necessary for surface localization of native LRRC32 following activation of naturally-occurring freshly-isolated regulatory T cells. LRRC32 expression appears to alter the surface expression of activation markers of T cells such as CD62L. LRRC32 surface expression may be useful as a marker that selects for more potent Treg populations. In summary, understanding the processing and expression of LRRC32 may provide insight into the mechanism of action of Tregs and the refinement of immunotherapeutic strategies aimed at targeting these cells.

  5. Identification of the First Riboflavin Catabolic Gene Cluster Isolated from Microbacterium maritypicum G10.

    Science.gov (United States)

    Xu, Hui; Chakrabarty, Yindrila; Philmus, Benjamin; Mehta, Angad P; Bhandari, Dhananjay; Hohmann, Hans-Peter; Begley, Tadhg P

    2016-11-04

    Riboflavin is a common cofactor, and its biosynthetic pathway is well characterized. However, its catabolic pathway, despite intriguing hints in a few distinct organisms, has never been established. This article describes the isolation of a Microbacterium maritypicum riboflavin catabolic strain, and the cloning of the riboflavin catabolic genes. RcaA, RcaB, RcaD, and RcaE were overexpressed and biochemically characterized as riboflavin kinase, riboflavin reductase, ribokinase, and riboflavin hydrolase, respectively. Based on these activities, a pathway for riboflavin catabolism is proposed.

  6. Structural Organization of Enzymes of the Phenylacetate Catabolic Hybrid Pathway

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    Andrey M. Grishin

    2015-06-01

    Full Text Available Aromatic compounds are the second most abundant class of molecules on the earth and frequent environmental pollutants. They are difficult to metabolize due to an inert chemical structure, and of all living organisms, only microbes have evolved biochemical pathways that can open an aromatic ring and catabolize thus formed organic molecules. In bacterial genomes, the phenylacetate (PA utilization pathway is abundant and represents the central route for degradation of a variety of organic compounds, whose degradation reactions converge at this pathway. The PA pathway is a hybrid pathway and combines the dual features of aerobic metabolism, i.e., usage of both oxygen to open the aromatic ring and of anaerobic metabolism—coenzyme A derivatization of PA. This allows the degradation process to be adapted to fluctuating oxygen conditions. In this review we focus on the structural and functional aspects of enzymes and their complexes involved in the PA degradation by the catabolic hybrid pathway. We discuss the ability of the central PaaABCE monooxygenase to reversibly oxygenate PA, the controlling mechanisms of epoxide concentration by the pathway enzymes, and the similarity of the PA utilization pathway to the benzoate utilization Box pathway and β-oxidation of fatty acids.

  7. Structural Organization of Enzymes of the Phenylacetate Catabolic Hybrid Pathway.

    Science.gov (United States)

    Grishin, Andrey M; Cygler, Miroslaw

    2015-06-12

    Aromatic compounds are the second most abundant class of molecules on the earth and frequent environmental pollutants. They are difficult to metabolize due to an inert chemical structure, and of all living organisms, only microbes have evolved biochemical pathways that can open an aromatic ring and catabolize thus formed organic molecules. In bacterial genomes, the phenylacetate (PA) utilization pathway is abundant and represents the central route for degradation of a variety of organic compounds, whose degradation reactions converge at this pathway. The PA pathway is a hybrid pathway and combines the dual features of aerobic metabolism, i.e., usage of both oxygen to open the aromatic ring and of anaerobic metabolism-coenzyme A derivatization of PA. This allows the degradation process to be adapted to fluctuating oxygen conditions. In this review we focus on the structural and functional aspects of enzymes and their complexes involved in the PA degradation by the catabolic hybrid pathway. We discuss the ability of the central PaaABCE monooxygenase to reversibly oxygenate PA, the controlling mechanisms of epoxide concentration by the pathway enzymes, and the similarity of the PA utilization pathway to the benzoate utilization Box pathway and β-oxidation of fatty acids.

  8. Research Progress on Glucokinase Regulatory Protein%葡萄糖激酶调节蛋白的研究进展

    Institute of Scientific and Technical Information of China (English)

    方亦斌; 邹大进

    2003-01-01

    葡萄糖激酶调节蛋白(glucokinase regulatory protein, GKRP)是一种主要存在于肝细胞内分子量68kDa的蛋白质,能与葡萄糖激酶(glucokinase, GK)结合而抑制其活性. 由于葡萄糖激酶在糖代谢中的重要作用:GK基因突变与青年发病型糖尿病(maturity-onse t diabetes of the young, MODY)发病的关系,尤其是最近发现的GKRP对糖尿病的治疗作用,使GKRP的研究价值得到了进一步的肯定.GKRP基因治疗可能会成为2型糖尿病治疗史上的新突破.

  9. Potential of acute phase proteins as predictor of postpartum uterine infections during transition period and its regulatory mechanism in dairy cattle

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    A. Manimaran

    2016-01-01

    Full Text Available Among the various systemic reactions against infection or injury, the acute phase response is the cascade of reaction and mostly coordinated by cytokines-mediated acute phase proteins (APPs production. Since APPs are sensitive innate immune molecules, they are useful for early detection of inflammation in bovines and believed to be better discriminators than routine hematological parameters. Therefore, the possibility of using APPs as a diagnostic and prognostic marker of inflammation in major bovine health disorders including postpartum uterine infection has been explored by many workers. In this review, we discussed specifically importance of postpartum uterine infection, the role of energy balance in uterine infections and potential of APPs as a predictor of postpartum uterine infections during the transition period and its regulatory mechanism in dairy cattle.

  10. Cyclic AMP-dependent protein kinase (cAPK) regulatory subunits are packaged and secreted by many exocrine and endocrine cells

    Energy Technology Data Exchange (ETDEWEB)

    Mednieks, M.I.; Hand, A.R.

    1986-05-01

    Regulatory (R) subunits of cAPK were identified by us as components of rat and human saliva by photoaffinity labeling with (/sup 32/P)-8-azido cyclic AMP. Photoaffinity labeling of purified rat parotid granule contents and immunogold labeling of thin sections with monoclonal antibodies showed the presence of R subunits in granules. The authors now report that cAPK R subunits are present in secretory granules and are apparently secreted by many exocrine and endocrine cell types. Labeling of thin sections of rat tissues with antibody to R subunits and protein A-gold shows gold particles over secretory granules of endocrine cells of the pituitary, pancreas and intestine. Zymogen granules of exocrine pancreatic acinar cells, the dense cores of secretory granules of seminal vesicle epithelial cells and secretory product in the seminal vesicle lumina were prominently labeled with gold. Photoaffinity labeling shows that pancreatic secretions and seminal vesicle contents have cAPK components. Phosphorylative modification of cellular proteins by cAMP controls hormonally stimulated protein secretion by many cell types. Although no catalytic activity was detected, identification of R subunits in granules and as secretory products indicates that they may have multiple roles in cellular mechanisms of action of cyclic AMP-mediated events in secretory cells.

  11. Enhanced Inhibition of Prostate Tumor Growth by Dual Targeting the Androgen Receptor and the Regulatory Subunit Type Iα of Protein Kinase A in Vivo

    Science.gov (United States)

    Eder, Iris E.; Egger, Martina; Neuwirt, Hannes; Seifarth, Christof; Maddalo, Danilo; Desiniotis, Andreas; Schäfer, Georg; Puhr, Martin; Bektic, Jasmin; Cato, Andrew C. B.; Klocker, Helmut

    2013-01-01

    Progression to castration resistance is a major problem in the treatment of advanced prostate cancer and is likely to be driven by activation of several molecular pathways, including androgen receptor (AR) and cyclic AMP-dependent protein kinase A (PKA). In this study, we examined the therapeutic efficacy of a combined inhibition of the AR and the regulatory subunit type Iα (RIα) of protein kinase A with second generation antisense oligonucleotides (ODNs) in androgen-sensitive LNCaP and castration-resistant LNCaPabl tumors in vivo. We found that targeting the AR alone inhibited LNCaP, as well as LNCaPabl tumors. Combined inhibition resulted in an improved response over single targeting and even a complete tumor remission in LNCaPabl. Western blot analysis revealed that both ODNs were effective in reducing their target proteins when administered alone or in combination. In addition, treatment with the ODNs was associated with an induction of apoptosis. Our data suggest that dual targeting of the AR and PKARIα is more effective in inhibiting LNCaP and LNCaPabl tumor growth than single treatment and may give a treatment benefit, especially in castration-resistant prostate cancers. PMID:23736698

  12. Regulatory elements in the promoter region of the rat gene encoding the acyl-CoA-binding protein

    DEFF Research Database (Denmark)

    Elholm, M; Bjerking, G; Knudsen, J

    1996-01-01

    Acyl-CoA-binding protein (ACBP) is an ubiquitously expressed 10-kDa protein which is present in high amounts in cells involved in solute transport or secretion. Rat ACBP is encoded by a gene containing the typical hallmarks of a housekeeping gene. Analysis of the promoter region of the rat ACBP...... gene by electrophoretic mobility shift assay (EMSA) revealed specific binding of proteins from rat liver nuclear extracts to potential recognition sequences of NF-1/CTF, Sp1, AP-1, C/EBP and HNF-3. In addition, specific binding to a DR-1 type element was observed. By using in vitro translated...... for the ACBP DR-1 element. Addition of peroxisome proliferators (PP) to H4IIEC3 rat hepatoma cells led to an increase in the ACBP mRNA level, indicating that the DR-1 element could be a functional peroxisome proliferator responsive element (PPRE). Analysis of the ACBP promoter by transient transfection showed...

  13. Metal ion interaction of an oligopeptide fragment representing the regulatory metal binding site of a CueR protein

    DEFF Research Database (Denmark)

    Jancsó, Attila; Szokolai, Hajnalka; Roszahegyi, Livia;

    2013-01-01

    Metalloregulatory proteins of the MerR family are transcriptional activators that sense/control the concentration of various metal ions inside bacteria.1 The Cu+ efflux regulator CueR, similarly to other MerR proteins, possesses a short multiple Cys-containing metal binding loop close to the C......-terminus. CueR has a high selectivity for Cu+, Ag+ and Au+, but exhibits no transcriptional activity for the divalent ions Hg2+ and Zn2+.2 The two Cys- residues of the metal binding loop were shown to settle M+ ions into a linear coordination environment but other factors may also play a role in the recognition...... of cognate metal ions.2 Nevertheless, it is an interesting question whether the same sequence, when removed from the protein, shows a flexibility to adopt different coordination environments and may efficiently bind metal ions having preferences for larger coordination numbers....

  14. The Yersinia enterocolitica type three secretion chaperone SycO is integrated into the Yop regulatory network and binds to the Yop secretion protein YscM1

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    Heesemann Jürgen

    2007-07-01

    Full Text Available Abstract Background Pathogenic yersiniae (Y. pestis, Y. pseudotuberculosis, Y. enterocolitica share a virulence plasmid encoding a type three secretion system (T3SS. This T3SS comprises more than 40 constituents. Among these are the transport substrates called Yops (Yersinia outer proteins, the specific Yop chaperones (Sycs, and the Ysc (Yop secretion proteins which form the transport machinery. The effectors YopO and YopP are encoded on an operon together with SycO, the chaperone of YopO. The characterization of SycO is the focus of this study. Results We have established the large-scale production of recombinant SycO in its outright form. We confirm that Y. enterocolitica SycO forms homodimers which is typical for Syc chaperones. SycO overproduction in Y. enterocolitica decreases secretion of Yops into the culture supernatant suggesting a regulatory role of SycO in type III secretion. We demonstrate that in vitro SycO interacts with YscM1, a negative regulator of Yop expression in Y. enterocolitica. However, the SycO overproduction phenotype was not mediated by YscM1, YscM2, YopO or YopP as revealed by analysis of isogenic deletion mutants. Conclusion We present evidence that SycO is integrated into the regulatory network of the Yersinia T3SS. Our picture of the Yersinia T3SS interactome is supplemented by identification of the SycO/YscM1 interaction. Further, our results suggest that at least one additional interaction partner of SycO has to be identified.

  15. Variations in the Regulatory Region of Alpha S1-Casein Milk Protein Gene among Tropically Adapted Indian Native (Bos Indicus) Cattle

    Science.gov (United States)

    Kishore, Amit; Mukesh, Manishi; Sobti, Ranbir C.; Mishra, Bishnu P.; Sodhi, Monika

    2013-01-01

    Regulatory region of milk protein alpha S1-casein (αS1-CN) gene was sequenced, characterized, and analyzed to detect variations among 13 Indian cattle (Bos indicus) breeds. Comparative analysis of 1,587 bp region comprising promoter (1,418 bp), exon-I (53 bp), and partial intron-I (116 bp) revealed 35 nucleotide substitutions (32 within promoter region, 1 in exon-I, and 2 in partial intron-I region) and 4 Indels. Within promoter, 15 variations at positions −1399 (A > G), −1288 (G > A), −1259 (T > C), −1158 (T > C), −1016 (A > T), −941 (T > G), −778 (C > T), −610 (G > A), −536 (A > G), −521 (A > G), −330 (A > C), −214 (A > G), −205 (A > T), −206 (C > A), and −175 (A > G) were located within the potential transcription factor binding sites (TFBSs), namely, NF-κE1/c-Myc, GATA-1, GATA-1/NF-E, Oct-1/POU3F2, MEF-2/YY1, GATA-1, AP-1, POU1F1a/GR, TMF, GAL4, YY1/Oct-1, HNF-1, GRalpha/AR, GRalpha/AR, and AP-1, respectively. Seventy-four percent (26/35) of the observed SNPs were novel to Indian cattle and 11 of these novel SNPs were located within one or more TFBSs. Collectively, these might influence the binding affinity towards their respective nuclear TFs thus modulating the level of transcripts in milk and affecting overall protein composition. The study provides information on several distinct variations across indicine and taurine αS1-CN regulatory domains. PMID:25937984

  16. Regulation of Calcium-Independent Phospholipase A2 Expression by Adrenoceptors and Sterol Regulatory Element Binding Protein-Potential Crosstalk Between Sterol and Glycerophospholipid Mediators.

    Science.gov (United States)

    Chew, Wee-Siong; Ong, Wei-Yi

    2016-01-01

    Calcium-independent phospholipase A2 (iPLA2) is an 85-kDa enzyme that releases docosahexaenoic acid (DHA) from glycerophospholipids. DHA can be metabolized to resolvins and neuroprotectins that have anti-inflammatory properties and effects on neural plasticity. Recent studies show an important role of prefrontal cortical iPLA2 in hippocampo-prefrontal cortical LTP and antidepressant-like effect of the norepinephrine reuptake inhibitor (NRI) antidepressant, maprotiline. In this study, we elucidated the cellular mechanisms through which stimulation of adrenergic receptors could lead to increased iPLA2 expression. Treatment of SH-SY5Y neuroblastoma cells with maprotiline, another tricyclic antidepressant with noradrenaline reuptake inhibiting properties, nortriptyline, and the adrenergic receptor agonist, phenylephrine, resulted in increased iPLA2β mRNA expression. This increase was blocked by inhibitors to alpha-1 adrenergic receptor, mitogen-activated protein (MAP) kinase or extracellular signal-regulated kinase (ERK) 1/2, and sterol regulatory element-binding protein (SREBP). Maprotiline and phenylephrine induced binding of SREBP-2 to sterol regulatory element (SRE) region on the iPLA2 promoter, as determined by electrophoretic mobility shift assay (EMSA). Together, results indicate that stimulation of adrenoreceptors causes increased iPLA2 expression via MAP kinase/ERK 1/2 and SREBP, and suggest a possible mechanism for effect of CNS noradrenaline on neural plasticity and crosstalk between sterol and glycerophospholipid mediators, that may play a role in physiological or pathophysiological processes in the brain and other organs.

  17. Regulatory network controlling extracellular proteins in Erwinia carotovora subsp. carotovora: FlhDC, the master regulator of flagellar genes, activates rsmB regulatory RNA production by affecting gacA and hexA (lrhA) expression.

    Science.gov (United States)

    Cui, Yaya; Chatterjee, Asita; Yang, Hailian; Chatterjee, Arun K

    2008-07-01

    Erwinia carotovora subsp. carotovora produces an array of extracellular proteins (i.e., exoproteins), including plant cell wall-degrading enzymes and Harpin, an effector responsible for eliciting hypersensitive reaction. Exoprotein genes are coregulated by the quorum-sensing signal, N-acyl homoserine lactone, plant signals, an assortment of transcriptional factors/regulators (GacS/A, ExpR1, ExpR2, KdgR, RpoS, HexA, and RsmC) and posttranscriptional regulators (RsmA, rsmB RNA). rsmB RNA production is positively regulated by GacS/A, a two-component system, and negatively regulated by HexA (PecT in Erwinia chrysanthemi; LrhA [LysR homolog A] in Escherichia coli) and RsmC, a putative transcriptional adaptor. While free RsmA, an RNA-binding protein, promotes decay of mRNAs of exoprotein genes, binding of RsmA with rsmB RNA neutralizes the RsmA effect. In the course of studies of GacA regulation, we discovered that a locus bearing strong homology to the flhDC operon of E. coli also controls extracellular enzyme production. A transposon insertion FlhDC(-) mutant produces very low levels of pectate lyase, polygalacturonase, cellulase, protease, and E. carotovora subsp. carotovora Harpin (Harpin(Ecc)) and is severely attenuated in its plant virulence. The production of these exoproteins is restored in the mutant carrying an FlhDC(+) plasmid. Sequence analysis and transcript assays disclosed that the flhD operon of E. carotovora subsp. carotovora, like those of other enterobacteria, consists of flhD and flhC. Complementation analysis revealed that the regulatory effect requires functions of both flhD and flhC products. The data presented here show that FlhDC positively regulates gacA, rsmC, and fliA and negatively regulates hexA (lrhA). Evidence shows that FlhDC controls extracellular protein production through cumulative effects on hexA and gacA. Reduced levels of GacA and elevated levels of HexA in the FlhDC(-) mutant are responsible for the inhibition of rsmB RNA

  18. Branched-chain and aromatic amino acid catabolism into aroma volatiles in Cucumis melo L. fruit.

    Science.gov (United States)

    Gonda, Itay; Bar, Einat; Portnoy, Vitaly; Lev, Shery; Burger, Joseph; Schaffer, Arthur A; Tadmor, Ya'akov; Gepstein, Shimon; Giovannoni, James J; Katzir, Nurit; Lewinsohn, Efraim

    2010-02-01

    The unique aroma of melons (Cucumis melo L., Cucurbitaceae) is composed of many volatile compounds biosynthetically derived from fatty acids, carotenoids, amino acids, and terpenes. Although amino acids are known precursors of aroma compounds in the plant kingdom, the initial steps in the catabolism of amino acids into aroma volatiles have received little attention. Incubation of melon fruit cubes with amino acids and alpha-keto acids led to the enhanced formation of aroma compounds bearing the side chain of the exogenous amino or keto acid supplied. Moreover, L-[(13)C(6)]phenylalanine was also incorporated into aromatic volatile compounds. Amino acid transaminase activities extracted from the flesh of mature melon fruits converted L-isoleucine, L-leucine, L-valine, L-methionine, or L-phenylalanine into their respective alpha-keto acids, utilizing alpha-ketoglutarate as the amine acceptor. Two novel genes were isolated and characterized (CmArAT1 and CmBCAT1) encoding 45.6 kDa and 42.7 kDa proteins, respectively, that displayed aromatic and branched-chain amino acid transaminase activities, respectively, when expressed in Escherichia coli. The expression of CmBCAT1 and CmArAT1 was low in vegetative tissues, but increased in flesh and rind tissues during fruit ripening. In addition, ripe fruits of climacteric aromatic cultivars generally showed high expression of CmBCAT1 and CmArAT1 in contrast to non-climacteric non-aromatic fruits. The results presented here indicate that in melon fruit tissues, the catabolism of amino acids into aroma volatiles can initiate through a transamination mechanism, rather than decarboxylation or direct aldehyde synthesis, as has been demonstrated in other plants.

  19. Training reduces catabolic and inflammatory response to a single practice in female volleyball players.

    Science.gov (United States)

    Eliakim, Alon; Portal, Shawn; Zadik, Zvi; Meckel, Yoav; Nemet, Dan

    2013-11-01

    We examined the effect of training on hormonal and inflammatory response to a single volleyball practice in elite adolescent players. Thirteen female, national team level, Israeli volleyball players (age 16.0 ± 1.4 years, Tanner stage 4-5) participated in the study. Blood samples were collected before and immediately after a typical 60 minutes of volleyball practice, before and after 7 weeks of training during the initial phase of the season. Training involved tactic and technical drills (20% of time), power and speed drills (25% of time), interval sessions (25% of time), endurance-type training (15% of time), and resistance training (15% of time). To achieve greater training responses, the study was performed during the early phase (first 7 weeks) of the volleyball season. Hormonal measurements included the anabolic hormones growth hormone (GH), insulin-like growth factor-I (IGF-I) and IGF-binding protein-3, the catabolic hormone cortisol, the proinflammatory marker interleukin-6 (IL-6), and the anti-inflammatory marker IL-1 receptor antagonist. Training led to a significant improvement of vertical jump, anaerobic properties (peak and mean power by the Wingate Anaerobic Test), and predicted VO2max (by the 20-m shuttle run). Volleyball practice, both before and after the training intervention, was associated with a significant increase of serum lactate, GH, and IL-6. Training resulted in a significantly reduced cortisol response ([INCREMENT]cortisol: 4.2 ± 13.7 vs. -4.4 ± 12.3 ng · ml, before and after training, respectively; p volleyball practice. The results suggest that along with the improvement of power and anaerobic and aerobic characteristics, training reduces the catabolic and inflammatory response to exercise.

  20. Imaging B. anthracis heme catabolism in mice using the IFP1.4 gene reporter

    Science.gov (United States)

    Zhu, Banghe; Robinson, Holly; Wilganowski, Nathaniel; Nobles, Christopher L.; Sevick-Muraca, Eva; Maresso, Anthony

    2012-03-01

    B. anthracis is a gram-positive, spore-forming bacterium which likes all pathogenic bacteria, survive by sequestering heme from its host. To image B. anthracis heme catabolism in vivo, we stably transfect new red excitable fluorescent protein, IFP1.4, that requires the heme catabolism product biliverdin (BV). IFP1.4 reporter has favorable excitation and emission characteristics, which has an absorption peak at 685 nm and an emission peak at 708 nm. Therefore, IFP1.4 reporter can be imaged deeply into the tissue with less contamination from tissue autofluorescence. However, the excitation light "leakage" through optical filters can limit detection and sensitivity of IFP1.4 reporter due to the small Stoke's shift of IFP1.4 fluorescence. To minimize the excitation light leakage, an intensified CCD (ICCD) based infrared fluorescence imaging device was optimized using two band pass filters separated by a focus lens to increase the optical density at the excitation wavelength. In this study, a mouse model (DBA/J2) was first injected with B. anthracis bacteria expressing IFP1.4, 150 μl s.c., on the ventral side of the left thigh. Then mouse was given 250 μl of a 1mM BV solution via I.V. injection. Imaging was conducted as a function of time after infection under light euthanasia, excised tissues were imaged and IFP1.4 fluorescence correlated with standard culture measurements of colony forming units (CFU). The work demonstrates the use of IFP1.4 as a reporter of bacterial utilization of host heme and may provide an important tool for understanding the pathogenesis of bacterial infection and developing new anti-bacterial therapeutics.

  1. Dissecting the expression relationships between RNA-binding proteins and their cognate targets in eukaryotic post-transcriptional regulatory networks

    Science.gov (United States)

    Nishtala, Sneha; Neelamraju, Yaseswini; Janga, Sarath Chandra

    2016-05-01

    RNA-binding proteins (RBPs) are pivotal in orchestrating several steps in the metabolism of RNA in eukaryotes thereby controlling an extensive network of RBP-RNA interactions. Here, we employed CLIP (cross-linking immunoprecipitation)-seq datasets for 60 human RBPs and RIP-ChIP (RNP immunoprecipitation-microarray) data for 69 yeast RBPs to construct a network of genome-wide RBP- target RNA interactions for each RBP. We show in humans that majority (~78%) of the RBPs are strongly associated with their target transcripts at transcript level while ~95% of the studied RBPs were also found to be strongly associated with expression levels of target transcripts when protein expression levels of RBPs were employed. At transcript level, RBP - RNA interaction data for the yeast genome, exhibited a strong association for 63% of the RBPs, confirming the association to be conserved across large phylogenetic distances. Analysis to uncover the features contributing to these associations revealed the number of target transcripts and length of the selected protein-coding transcript of an RBP at the transcript level while intensity of the CLIP signal, number of RNA-Binding domains, location of the binding site on the transcript, to be significant at the protein level. Our analysis will contribute to improved modelling and prediction of post-transcriptional networks.

  2. A regulatory effect of INMAP on centromere proteins: antisense INMAP induces CENP-B variation and centromeric halo.

    Directory of Open Access Journals (Sweden)

    Tan Tan

    Full Text Available CENP-B is a highly conserved protein that facilitates the assembly of specific centromere structures both in interphase nuclei and on mitotic chromosomes. INMAP is a conserved protein that localizes at nucleus in interphase cells and at mitotic apparatus in mitotic cells. Our previous results showed that INMAP over-expression leads to spindle defects, mitotic arrest and formation of polycentrosomal and multinuclear cells, indicating that INMAP may modulate the function of (a key protein(s in mitotic apparatus. In this study, we demonstrate that INMAP interacts with CENP-B and promotes cleavage of the N-terminal DNA binding domain from CENP-B. The cleaved CENP-B cannot associate with centromeres and thus lose its centromere-related functions. Consistent with these results, CENP-B in INMAP knockdown cells becomes more diffused around kinetochores. Although INMAP knockdown cells do not exhibit gross defects in mitotic spindle formation, these cells go through mitosis, especially prophase and metaphase, with different relative timing, indicating subtle abnormality. These results identify INMAP as a model regulator of CENP-B and support the notion that INMAP regulates mitosis through modulating CENP-B-mediated centromere organization.

  3. A regulatory effect of INMAP on centromere proteins: antisense INMAP induces CENP-B variation and centromeric halo.

    Science.gov (United States)

    Tan, Tan; Chen, Zhe; Lei, Yan; Zhu, Yan; Liang, Qianjin

    2014-01-01

    CENP-B is a highly conserved protein that facilitates the assembly of specific centromere structures both in interphase nuclei and on mitotic chromosomes. INMAP is a conserved protein that localizes at nucleus in interphase cells and at mitotic apparatus in mitotic cells. Our previous results showed that INMAP over-expression leads to spindle defects, mitotic arrest and formation of polycentrosomal and multinuclear cells, indicating that INMAP may modulate the function of (a) key protein(s) in mitotic apparatus. In this study, we demonstrate that INMAP interacts with CENP-B and promotes cleavage of the N-terminal DNA binding domain from CENP-B. The cleaved CENP-B cannot associate with centromeres and thus lose its centromere-related functions. Consistent with these results, CENP-B in INMAP knockdown cells becomes more diffused around kinetochores. Although INMAP knockdown cells do not exhibit gross defects in mitotic spindle formation, these cells go through mitosis, especially prophase and metaphase, with different relative timing, indicating subtle abnormality. These results identify INMAP as a model regulator of CENP-B and support the notion that INMAP regulates mitosis through modulating CENP-B-mediated centromere organization.

  4. The old 3-oxoadipate pathway revisited: new insights in the catabolism of aromatics in the saprophytic fungus Aspergillus nidulans.

    Science.gov (United States)

    Martins, Tiago M; Hartmann, Diego O; Planchon, Sébastien; Martins, Isabel; Renaut, Jenny; Silva Pereira, Cristina

    2015-01-01

    Aspergilli play major roles in the natural turnover of elements, especially through the decomposition of plant litter, but the end catabolism of lignin aromatic hydrocarbons remains largely unresolved. The 3-oxoadipate pathway of their degradation combines the catechol and the protocatechuate branches, each using a set of specific genes. However, annotation for most of these genes is lacking or attributed to poorly- or un-characterised families. Aspergillus nidulans can utilise as sole carbon/energy source either benzoate or salicylate (upstream aromatic metabolites of the protocatechuate and the catechol branches, respectively). Using this cultivation strategy and combined analyses of comparative proteomics, gene mining, gene expression and characterisation of particular gene-replacement mutants, we precisely assigned most of the steps of the 3-oxoadipate pathway to specific genes in this fungus. Our findings disclose the genetically encoded potential of saprophytic Ascomycota fungi to utilise this pathway and provide means to untie associated regulatory networks, which are vital to heightening their ecological significance.

  5. The α-proteobacteria Wolbachia pipientis protein disulfide machinery has a regulatory mechanism absent in γ-proteobacteria.

    Directory of Open Access Journals (Sweden)

    Patricia M Walden

    Full Text Available The α-proteobacterium Wolbachia pipientis infects more than 65% of insect species worldwide and manipulates the host reproductive machinery to enable its own survival. It can live in mutualistic relationships with hosts that cause human disease, including mosquitoes that carry the Dengue virus. Like many other bacteria, Wolbachia contains disulfide bond forming (Dsb proteins that introduce disulfide bonds into secreted effector proteins. The genome of the Wolbachia strain wMel encodes two DsbA-like proteins sharing just 21% sequence identity to each other, α-DsbA1 and α-DsbA2, and an integral membrane protein, α-DsbB. α-DsbA1 and α-DsbA2 both have a Cys-X-X-Cys active site that, by analogy with Escherichia coli DsbA, would need to be oxidized to the disulfide form to serve as a disulfide bond donor toward substrate proteins. Here we show that the integral membrane protein α-DsbB oxidizes α-DsbA1, but not α-DsbA2. The interaction between α-DsbA1 and α-DsbB is very specific, involving four essential cysteines located in the two periplasmic loops of α-DsbB. In the electron flow cascade, oxidation of α-DsbA1 by α-DsbB is initiated by an oxidizing quinone cofactor that interacts with the cysteine pair in the first periplasmic loop. Oxidizing power is transferred to the second cysteine pair, which directly interacts with α-DsbA1. This reaction is inhibited by a non-catalytic disulfide present in α-DsbA1, conserved in other α-proteobacterial DsbAs but not in γ-proteobacterial DsbAs. This is the first characterization of the integral membrane protein α-DsbB from Wolbachia and reveals that the non-catalytic cysteines of α-DsbA1 regulate the redox relay system in cooperation with α-DsbB.

  6. The PDZ Protein Na+/H+ Exchanger Regulatory Factor-1 (NHERF1) Regulates Planar Cell Polarity and Motile Cilia Organization.

    Science.gov (United States)

    Treat, Anny Caceres; Wheeler, David S; Stolz, Donna B; Tsang, Michael; Friedman, Peter A; Romero, Guillermo

    2016-01-01

    Directional flow of the cerebrospinal fluid requires coordinated movement of the motile cilia of the ependymal epithelium that lines the cerebral ventricles. Here we report that mice lacking the Na+/H+ Exchanger Regulatory Factor 1 (NHERF1/Slc9a3r1, also known as EBP50) develop profound communicating hydrocephalus associated with fewer and disorganized ependymal cilia. Knockdown of NHERF1/slc9a3r1 in zebrafish embryos also causes severe hydrocephalus of the hindbrain and impaired ciliogenesis in the otic vesicle. Ultrastructural analysis did not reveal defects in the shape or organization of individual cilia. Similar phenotypes have been described in animals with deficiencies in Wnt signaling and the Planar Cell Polarity (PCP) pathway. We show that NHERF1 binds the PCP core genes Frizzled (Fzd) and Vangl. We further show that NHERF1 assembles a ternary complex with Fzd4 and Vangl2 and promotes translocation of Vangl2 to the plasma membrane, in particular to the apical surface of ependymal cells. Taken together, these results strongly support an important role for NHERF1 in the regulation of PCP signaling and the development of functional motile cilia.

  7. Stable Isotope Resolved Metabolomics Reveals the Role of Anabolic and Catabolic Processes in Glyphosate-Induced Amino Acid Accumulation in Amaranthus palmeri Biotypes.

    Science.gov (United States)

    Maroli, Amith; Nandula, Vijay; Duke, Stephen; Tharayil, Nishanth

    2016-09-21

    Biotic and abiotic stressors often result in the buildup of amino acid pools in plants, which serve as potential stress mitigators. However, the role of anabolic (de novo amino acid synthesis) versus catabolic (proteolytic) processes in contributing to free amino acid pools is less understood. Using stable isotope-resolved metabolomics (SIRM), we measured the de novo amino acid synthesis in glyphosate susceptible (S-) and resistant (R-) Amaranthus palmeri biotypes. In the S-biotype, glyphosate treatment at 0.4 kg ae/ha resulted in an increase in total amino acids, a proportional increase in both (14)N and (15)N amino acids, and a decrease in soluble proteins. This indicates a potential increase in de novo amino acid synthesis, coupled with a lower protein synthesis and a higher protein catabolism following glyphosate treatment in the S-biotype. Furthermore, the ratio of glutamine/glutamic acid (Gln/Glu) in the glyphosate-treated S- and R-biotypes indicated that the initial assimilation of inorganic nitrogen to organic forms is less affected by glyphosate. However, amino acid biosynthesis downstream of glutamine is disproportionately disrupted in the glyphosate treated S-biotype. It is thus concluded that the herbicide-induced amino acid abundance in the S-biotype is contributed by both protein catabolism and de novo synthesis of amino acids such as glutamine and asparagine.

  8. HbNIN2, a cytosolic alkaline/neutral-invertase, is responsible for sucrose catabolism in rubber-producing laticifers of Hevea brasiliensis (para rubber tree).

    Science.gov (United States)

    Liu, Shujin; Lan, Jixian; Zhou, Binhui; Qin, Yunxia; Zhou, Yihua; Xiao, Xiaohu; Yang, Jianghua; Gou, Jiqing; Qi, Jiyan; Huang, Yacheng; Tang, Chaorong

    2015-04-01

    In Hevea brasiliensis, an alkaline/neutral invertase (A/N-Inv) is responsible for sucrose catabolism in latex (essentially the cytoplasm of rubber-producing laticifers, the source of natural rubber) and implicated in rubber yield. However, neither the gene encoding this enzyme nor its molecular and biochemical properties have been well documented. Three Hevea A/N-Inv genes, namely HbNIN1, 2 and 3, were first cloned and characterized in planta and in Escherichia coli. Cellular localizations of HbNIN2 mRNA and protein were probed. From latex, active A/N-Inv proteins were purified, identified, and explored for enzymatic properties. HbNIN2 was identified as the major A/N-Inv gene functioning in latex based on its functionality in E. coli, its latex-predominant expression, the conspicuous localization of its mRNA and protein in the laticifers, and its expressional correlation with rubber yield. An active A/N-Inv protein was partially purified from latex, and determined as HbNIN2. The enhancement of HbNIN2 enzymatic activity by pyridoxal is peculiar to A/N-Invs in other plants. We conclude that HbNIN2, a cytosolic A/N-Inv, is responsible for sucrose catabolism in rubber laticifers. The results contribute to the studies of sucrose catabolism in plants as a whole and natural rubber synthesis in particular.

  9. Catabolism of Phenol and Its Derivatives in Bacteria: Genes, Their Regulation, and Use in the Biodegradation of Toxic Pollutants.

    Science.gov (United States)

    Nešvera, Jan; Rucká, Lenka; Pátek, Miroslav

    2015-01-01

    Phenol and its derivatives (alkylphenols, halogenated phenols, nitrophenols) are natural or man-made aromatic compounds that are ubiquitous in nature and in human-polluted environments. Many of these substances are toxic and/or suspected of mutagenic, carcinogenic, and teratogenic effects. Bioremediation of the polluted soil and water using various bacteria has proved to be a promising option for the removal of these compounds. In this review, we describe a number of peripheral pathways of aerobic and anaerobic catabolism of various natural and xenobiotic phenolic compounds, which funnel these substances into a smaller number of central catabolic pathways. Finally, the metabolites are used as carbon and energy sources in the citric acid cycle. We provide here the characteristics of the enzymes that convert the phenolic compounds and their catabolites, show their genes, and describe regulatory features. The genes, which encode these enzymes, are organized on chromosomes and plasmids of the natural bacterial degraders in various patterns. The accumulated data on similarities and the differences of the genes, their varied organization, and particularly, an astonishingly broad range of intricate regulatory mechanism may be read as an exciting adventurous book on divergent evolutionary processes and horizontal gene transfer events inscribed in the bacterial genomes. In the end, the use of this wealth of bacterial biodegradation potential and the manipulation of its genetic basis for purposes of bioremediation is exemplified. It is envisioned that the integrated high-throughput techniques and genome-level approaches will enable us to manipulate systems rather than separated genes, which will give birth to systems biotechnology.

  10. Arabidopsis CYP94B3 encodes jasmonyl-L-isoleucine 12-hydroxylase, a key enzyme in the oxidative catabolism of jasmonate.

    Science.gov (United States)

    Kitaoka, Naoki; Matsubara, Takuya; Sato, Michio; Takahashi, Kosaku; Wakuta, Shinji; Kawaide, Hiroshi; Matsui, Hirokazu; Nabeta, Kensuke; Matsuura, Hideyuki

    2011-10-01

    The hormonal action of jasmonate in plants is controlled by the precise balance between its biosynthesis and catabolism. It has been shown that jasmonyl-L-isoleucine (JA-Ile) is the bioactive form involved in the jasmonate-mediated signaling pathway. However, the catabolism of JA-Ile is poorly understood. Although a metabolite, 12-hydroxyJA-Ile, has been characterized, detailed functional studies of the compound and the enzyme that produces it have not been conducted. In this report, the kinetics of wound-induced accumulation of 12-hydroxyJA-Ile in plants were examined, and its involvement in the plant wound response is described. Candidate genes for the catabolic enzyme were narrowed down from 272 Arabidopsis Cyt P450 genes using Arabidopsis mutants. The candidate gene was functionally expressed in Pichia pastoris to reveal that CYP94B3 encodes JA-Ile 12-hydroxylase. Expression analyses demonstrate that expression of CYP94B3 is induced by wounding and shows specific activity toward JA-Ile. Plants grown in medium containing JA-Ile show higher sensitivity to JA-Ile in cyp94b3 mutants than in wild-type plants. These results demonstrate that CYP94B3 plays a major regulatory role in controlling the level of JA-Ile in plants.

  11. The Hepatitis C Virus-induced NLRP3 Inflammasome Activates the Sterol Regulatory Element-binding Protein (SREBP) and Regulates Lipid Metabolism.

    Science.gov (United States)

    McRae, Steven; Iqbal, Jawed; Sarkar-Dutta, Mehuli; Lane, Samantha; Nagaraj, Abhiram; Ali, Naushad; Waris, Gulam

    2016-02-12

    Hepatitis C virus (HCV) relies on host lipids and lipid droplets for replication and morphogenesis. The accumulation of lipid droplets in infected hepatocytes manifests as hepatosteatosis, a common pathology observed in chronic hepatitis C patients. One way by which HCV promotes the accumulation of intracellular lipids is through enhancing de novo lipogenesis by activating the sterol regulatory element-binding proteins (SREBPs). In general, activation of SREBPs occurs during cholesterol depletion. Interestingly, during HCV infection, the activation of SREBPs occurs under normal cholesterol levels, but the underlying mechanisms are still elusive. Our previous study has demonstrated the activation of the inflammasome complex in HCV-infected human hepatoma cells. In this study, we elucidate the potential link between chronic hepatitis C-associated inflammation and alteration of lipid homeostasis in infected cells. Our results reveal that the HCV-activated NLRP3 inflammasome is required for the up-regulation of lipogenic genes such as 3-hydroxy-3-methylglutaryl-coenzyme A synthase, fatty acid synthase, and stearoyl-CoA desaturase. Using pharmacological inhibitors and siRNA against the inflammasome components (NLRP3, apoptosis-associated speck-like protein containing a CARD, and caspase-1), we further show that the activation of the NLRP3 inflammasome plays a critical role in lipid droplet formation. NLRP3 inflammasome activation in HCV-infected cells enables caspase-1-mediated degradation of insulin-induced gene proteins. This subsequently leads to the transport of the SREBP cleavage-activating protein·SREBP complex from the endoplasmic reticulum to the Golgi, followed by proteolytic activation of SREBPs by S1P and S2P in the Golgi. Typically, inflammasome activation leads to viral clearance. Paradoxically, here we demonstrate how HCV exploits the NLRP3 inflammasome to activate SREBPs and host lipid metabolism, leading to liver disease pathogenesis associated with

  12. Stathmin/oncoprotein 18, a microtubule regulatory protein, is required for survival of both normal and cancer cell lines lacking the tumor suppressor, p53.

    Science.gov (United States)

    Carney, Bruce K; Cassimeris, Lynne

    2010-05-01

    Stathmin, a microtubule regulatory protein, is overexpressed in many cancers and required for survival of several cancer lines. In a study of breast cancer cell lines(1) proposed that stathmin is required for survival of cells lacking p53, but this hypothesis was not tested directly. Here we tested their hypothesis by examining cell survival in cells depleted of stathmin, p53 or both proteins. Comparing HCT116 colon cancer cell lines differing in TP53 genotype, stathmin depletion resulted in significant death only in cells lacking p53. As a second experimental system, we compared the effects of stathmin depletion from HeLa cells, which normally lack detectable levels of p53 due to expression of the HPV E6 protein. Stathmin depletion caused a large percentage of HeLa cells to die. Restoring p53, by depletion of HPV E6, rescued HeLa cells from stathmin-depletion induced death. Cleaved PARP was detected in HCT116(p53-/-) cells depleted of stathmin and cell death in stathmin-depleted HeLa cells was blocked by the caspase inhibitor Z-VAD-FMK, consistent with apoptotic death. The stathmin-dependent survival of cells lacking p53 was not confined to cancerous cells because both proteins were required for survival of normal human fibroblasts. In HCT116 and HeLa cells, depletion of both stathmin and p53 leads to a cell cycle delay through G(2). Our results demonstrate that stathmin is required for cell survival in cells lacking p53, suggesting that stathmin depletion could be used therapeutically to induce apoptosis in tumors without functional p53.

  13. Mechanistic basis of plasmid-specific DNA binding of the F plasmid regulatory protein, TraM.

    Science.gov (United States)

    Peng, Yun; Lu, Jun; Wong, Joyce J W; Edwards, Ross A; Frost, Laura S; Mark Glover, J N

    2014-11-11

    The conjugative transfer of bacterial F plasmids relies on TraM, a plasmid-encoded protein that recognizes multiple DNA sites to recruit the plasmid to the conjugative pore. In spite of the high degree of amino acid sequence conservation between TraM proteins, many of these proteins have markedly different DNA binding specificities that ensure the selective recruitment of a plasmid to its cognate pore. Here we present the structure of F TraM RHH (ribbon-helix-helix) domain bound to its sbmA site. The structure indicates that a pair of TraM tetramers cooperatively binds an underwound sbmA site containing 12 base pairs per turn. The sbmA is composed of 4 copies of a 5-base-pair motif, each of which is recognized by an RHH domain. The structure reveals that a single conservative amino acid difference in the RHH β-ribbon between F and pED208 TraM changes its specificity for its cognate 5-base-pair sequence motif. Specificity is also dictated by the positioning of 2-base-pair spacer elements within sbmA; in F sbmA, the spacers are positioned between motifs 1 and 2 and between motifs 3 and 4, whereas in pED208 sbmA, there is a single spacer between motifs 2 and 3. We also demonstrate that a pair of F TraM tetramers can cooperatively bind its sbmC site with an affinity similar to that of sbmA in spite of a lack of sequence similarity between these DNA elements. These results provide a basis for the prediction of the DNA binding properties of the family of TraM proteins.

  14. Comparisons of Ribosomal Protein Gene Promoters Indicate Superiority of Heterologous Regulatory Sequences for Expressing Transgenes in Phytophthora infestans.

    Science.gov (United States)

    Poidevin, Laetitia; Andreeva, Kalina; Khachatoorian, Careen; Judelson, Howard S

    2015-01-01

    Molecular genetics approaches in Phytophthora research can be hampered by the limited number of known constitutive promoters for expressing transgenes and the instability of transgene activity. We have therefore characterized genes encoding the cytoplasmic ribosomal proteins of Phytophthora and studied their suitability for expressing transgenes in P. infestans. Phytophthora spp. encode a standard complement of 79 cytoplasmic ribosomal proteins. Several genes are duplicated, and two appear to be pseudogenes. Half of the genes are expressed at similar levels during all stages of asexual development, and we discovered that the majority share a novel promoter motif named the PhRiboBox. This sequence is enriched in genes associated with transcription, translation, and DNA replication, including tRNA and rRNA biogenesis. Promoters from the three P. infestans genes encoding ribosomal proteins S9, L10, and L23 and their orthologs from P. capsici were tested for their ability to drive transgenes in stable transformants of P. infestans. Five of the six promoters yielded strong expression of a GUS reporter, but the stability of expression was higher using the P. capsici promoters. With the RPS9 and RPL10 promoters of P. infestans, about half of transformants stopped making GUS over two years of culture, while their P. capsici orthologs conferred stable expression. Since cross-talk between native and transgene loci may trigger gene silencing, we encourage the use of heterologous promoters in transformation studies.

  15. To Gate, or Not to Gate: Regulatory Mechanisms for Intercellular Protein Transport and Virus Movement in Plants

    Institute of Scientific and Technical Information of China (English)

    Shoko Ueki; Vitaly Citovsky

    2011-01-01

    Cell-to-cell signal transduction is vital for orchestrating the whole-body physiology of multi-cellular organisms,and many endogenous macromolecules,proteins,and nucleic acids function as such transported signals.In plants,many of these molecules are transported through plasmodesmata (Pd),the cell wall-spanning channel structures that interconnect plant cells.Furthermore,Pd also act as conduits for cell-to-cell movement of most plant viruses that have evolved to pirate these channels to spread the infection.Pd transport is presumed to be highly selective,and only a limited repertoire of molecules is transported through these channels.Recent studies have begun to unravel mechanisms that actively regulate the opening of the Pd channel to allow traffic.This macromolecular transport between cells comprises two consecutive steps:intracellular targeting to Pd and translocation through the channel to the adjacent cell.Here,we review the current knowledge of molecular species that are transported though Pd and the mechanisms that control this traffic.Generally,Pd traffic can occur by passive diffusion through the trans-Pd cytoplasm or through the membrane/lumen of the trans-Pd ER,or by active transport that includes protein-protein interactions.It is this latter mode of Pd transport that is involved in intercellular traffic of most signal molecules and is regulated by distinct and sometimes interdependent mechanisms,which represent the focus of this article.

  16. Mapping the ribosomal protein S7 regulatory binding site on mRNA of the E. coli streptomycin operon.

    Science.gov (United States)

    Surdina, A V; Rassokhin, T I; Golovin, A V; Spiridonova, V A; Kopylov, A M

    2010-07-01

    In this work it is shown by deletion analysis that an intercistronic region (ICR) approximately 80 nucleotides in length is necessary for interaction with recombinant E. coli S7 protein (r6hEcoS7). A model is proposed for the interaction of S7 with two ICR sites-region of hairpin bifurcations and Shine-Dalgarno sequence of cistron S7. A de novo RNA binding site for heterologous S7 protein of Thermus thermophilus (r6hTthS7) was constructed by selection of a combinatorial RNA library based on E. coli ICR: it has only a single supposed protein recognition site in the region of bifurcation. The SERW technique was used for selection of two intercistronic RNA libraries in which five nucleotides of a double-stranded region, adjacent to the bifurcation, had the randomized sequence. One library contained an authentic AG (-82/-20) pair, while in the other this pair was replaced by AU. A serwamer capable of specific binding to r6hTthS7 was selected; it appeared to be the RNA68 mutant with eight nucleotide mutations. The serwamer binds to r6hTthS7 with the same affinity as homologous authentic ICR of str mRNA binds to r6hEcoS7; apparent dissociation constants are 89 +/- 43 and 50 +/- 24 nM, respectively.

  17. Estimating fermentative amino acid catabolism in the small intestine of growing pigs.

    Science.gov (United States)

    Columbus, D A; Cant, J P; de Lange, C F M

    2015-11-01

    Fermentative catabolism (FAAC) of dietary and endogenous amino acids (AA) in the small intestine contributes to loss of AA available for protein synthesis and body maintenance functions in pigs. A continuous isotope infusion study was performed to determine whole body urea flux, urea recycling and FAAC in the small intestine of ileal-cannulated growing pigs fed a control diet (CON, 18.6% CP; n=6), a high fibre diet with 12% added pectin (HF, 17.7% CP; n = 4) or a low-protein diet (LP, 13.4% CP; n = 6). (15)N-ammonium chloride and (13)C-urea were infused intragastrically and intravenously, respectively, for 4 days. Recovery of ammonia at the distal ileum was increased by feeding additional fibre when compared with the CON (P > 0.05) but was not affected by dietary protein (0.24, 0.39 and 0.14 mmol nitrogen/kg BW/day for CON, HF and LP, respectively; P 0.05)compared with CON. The two-pool model developed in the present study allows for estimation of FAAC but still has limitations. Quantifying FAAC in the small intestine of pigs, as well as other non-ruminants and humans, offers a number of challenges but warrants further investigation.

  18. Distinct Tryptophan Catabolism and Th17/Treg Balance in HIV Progressors and Elite Controllers

    NARCIS (Netherlands)

    Jenabian, Mohammad-Ali; Patel, Mital; Kema, Ido; Kanagaratham, Cynthia; Radzioch, Danuta; Thebault, Pamela; Lapointe, Rejean; Tremblay, Cecile; Gilmore, Norbert; Ancuta, Petronela; Routy, Jean-Pierre

    2013-01-01

    Tryptophan (Trp) catabolism into immunosuppressive kynurenine (Kyn) by indoleamine 2,3-dioxygenase (IDO) was previously linked to Th17/Treg differentiation and immune activation. Here we examined Trp catabolism and its impact on Th17/Treg balance in uninfected healthy subjects (HS) and a large cohor

  19. Homologous gene clusters of nicotine catabolism, including a new ω-amidase for α-ketoglutaramate, in species of three genera of Gram-positive bacteria.

    Science.gov (United States)

    Cobzaru, Cristina; Ganas, Petra; Mihasan, Marius; Schleberger, Paula; Brandsch, Roderich

    2011-04-01

    Gram-positive soil bacteria Arthrobacter nicotinovorans, Nocardioides sp. JS614 and Rhodococcus opacus were shown to contain similarly organized clusters of homologous genes for nicotine catabolism. An uncharacterized gene of a predicted nitrilase within these gene clusters was cloned from A. nicotinovorans and biochemical data unexpectedly showed that the protein exhibited ω-amidase activity toward α-ketoglutaramate. Structural modelling of the protein suggested the presence of the catalytic triad Cys-Glu-Lys, characteristic of this class of enzymes, and supported α-ketoglutaramate as substrate. A-ketoglutaramate could be generated by hydrolytic cleavage of the C-N bond of the trihydroxypyridine ring produced by nicotine catabolism in these bacteria. This ω-amidase, together with glutamate dehydrogenase, may form a physiologically relevant enzyme couple, leading to transformation of metabolically inert α-ketoglutaramate derived from trihydroxypyridine into glutamate, a central compound of nitrogen metabolism.

  20. Metabolic control analysis of Aspergillus niger L-arabinose catabolism

    DEFF Research Database (Denmark)

    de Groot, M.J.L.; Prathumpai, Wai; Visser, J.

    2005-01-01

    -arabinose, a level that resulted in realistic intermediate concentrations in the model, flux control coefficients for L-arabinose reductase, L-arabitol dehydrogenase and L-xylulose reductase were 0.68, 0.17 and 0.14, respectively. The analysis can be used as a guide to identify targets for metabolic engineering......, and their kinetic properties were characterized. For the other enzymes of the pathway the kinetic data were available from the literature. The metabolic model was used to analyze flux and metabolite concentration control of the L-arabinose catabolic pathway. The model demonstrated that flux control does not reside...... at the enzyme following the intermediate with the highest concentration, L-arabitol, but is distributed over the first three steps in the pathway, preceding and following L-arabitol. Flux control appeared to be strongly dependent on the intracellular L-arabinose concentration. At 5 mM intracellular L...

  1. Identification of a gene cluster associated with triclosan catabolism.

    Science.gov (United States)

    Kagle, Jeanne M; Paxson, Clayton; Johnstone, Precious; Hay, Anthony G

    2015-06-01

    Aerobic degradation of bis-aryl ethers like the antimicrobial triclosan typically proceeds through oxygenase-dependent catabolic pathways. Although several studies have reported on bacteria capable of degrading triclosan aerobically, there are no reports describing the genes responsible for this process. In this study, a gene encoding the large subunit of a putative triclosan oxygenase, designated tcsA was identified in a triclosan-degrading fosmid clone from a DNA library of Sphingomonas sp. RD1. Consistent with tcsA's similarity to two-part dioxygenases, a putative FMN-dependent ferredoxin reductase, designated tcsB was found immediately downstream of tcsA. Both tcsAB were found in the midst of a putative chlorocatechol degradation operon. We show that RD1 produces hydroxytriclosan and chlorocatechols during triclosan degradation and that tcsA is induced by triclosan. This is the first study to report on the genetics of triclosan degradation.

  2. Epigenetic Regulation of Chondrocyte Catabolism and Anabolism in Osteoarthritis.

    Science.gov (United States)

    Kim, Hyeonkyeong; Kang, Donghyun; Cho, Yongsik; Kim, Jin-Hong

    2015-08-01

    Osteoarthritis (OA) is one of the most prevalent forms of joint disorder, associated with a tremendous socioeconomic burden worldwide. Various non-genetic and lifestyle-related factors such as aging and obesity have been recognized as major risk factors for OA, underscoring the potential role for epigenetic regulation in the pathogenesis of the disease. OA-associated epigenetic aberrations have been noted at the level of DNA methylation and histone modification in chondrocytes. These epigenetic regulations are implicated in driving an imbalance between the expression of catabolic and anabolic factors, leading eventually to osteoarthritic cartilage destruction. Cellular senescence and metabolic abnormalities driven by OA-associated risk factors appear to accompany epigenetic drifts in chondrocytes. Notably, molecular events associated with metabolic disorders influence epigenetic regulation in chondrocytes, supporting the notion that OA is a metabolic disease. Here, we review accumulating evidence supporting a role for epigenetics in the regulation of cartilage homeostasis and OA pathogenesis.

  3. A Promoter Polymorphism in the CD59 Complement Regulatory Protein Gene in Donor Lungs Correlates With a Higher Risk for Chronic Rejection After Lung Transplantation.

    Science.gov (United States)

    Budding, K; van de Graaf, E A; Kardol-Hoefnagel, T; Broen, J C A; Kwakkel-van Erp, J M; Oudijk, E-J D; van Kessel, D A; Hack, C E; Otten, H G

    2016-03-01

    Complement activation leads primarily to membrane attack complex formation and subsequent target cell lysis. Protection against self-damage is regulated by complement regulatory proteins, including CD46, CD55, and CD59. Within their promoter regions, single-nucleotide polymorphisms (SNPs) are present that could influence transcription. We analyzed these SNPs and investigated their influence on protein expression levels. A single SNP configuration in the promoter region of CD59 was found correlating with lower CD59 expression on lung endothelial cells (p = 0.016) and monocytes (p = 0.013). Lung endothelial cells with this SNP configuration secreted more profibrotic cytokine IL-6 (p = 0.047) and fibroblast growth factor β (p = 0.036) on exposure to sublytic complement activation than cells with the opposing configuration, whereas monocytes were more susceptible to antibody-mediated complement lysis (p < 0.0001). Analysis of 137 lung transplant donors indicated that this CD59 SNP configuration correlates with impaired long-term survival (p = 0.094) and a significantly higher incidence of bronchiolitis obliterans syndrome (p = 0.046) in the recipient. These findings support a role for complement in the pathogenesis of this posttransplant complication and are the first to show a deleterious association of a donor CD59 promoter polymorphism in lung transplantation.

  4. A Recombinant G Protein Plus Cyclosporine A-Based Respiratory Syncytial Virus Vaccine Elicits Humoral and Regulatory T Cell Responses against Infection without Vaccine-Enhanced Disease.

    Science.gov (United States)

    Li, Chaofan; Zhou, Xian; Zhong, Yiwei; Li, Changgui; Dong, Aihua; He, Zhonghuai; Zhang, Shuren; Wang, Bin

    2016-02-15

    Respiratory syncytial virus (RSV) infection can cause severe disease in the lower respiratory tract of infants and older people. Vaccination with a formalin-inactivated RSV vaccine (FI-RSV) and subsequent RSV infection has led to mild to severe pneumonia with two deaths among vaccinees. The vaccine-enhanced disease (VED) was recently demonstrated to be due to an elevated level of Th2 cell responses following loss of regulatory T (Treg) cells from the lungs. To induce high levels of neutralizing Abs and minimize pathogenic T cell responses, we developed a novel strategy of immunizing animals with a recombinant RSV G protein together with cyclosporine A. This novel vaccine induced not only a higher level of neutralizing Abs against RSV infection, but, most importantly, also significantly higher levels of Treg cells that suppressed VED in the lung after RSV infection. The induced responses provided protection against RSV challenge with no sign of pneumonia or bronchitis. Treg cell production of IL-10 was one of the key factors to suppress VED. These finding indicate that G protein plus cyclosporine A could be a promising vaccine against RSV infection in children and older people.

  5. Steroidogenic acute regulatory protein in white sturgeon (Acipenser transmontanus): cDNA cloning, sites of expression and transcript abundance in corticosteroidogenic tissue after an acute stressor.

    Science.gov (United States)

    Kusakabe, Makoto; Zuccarelli, Micah D; Nakamura, Ikumi; Young, Graham

    2009-06-01

    The white sturgeon, Acipenser transmontanus, is a primitive bony fish that is recognized as an important emerging species for aquaculture. However, many aspects of its stress and reproductive physiology remain unclear. These processes are controlled by various steroid hormones. In order to investigate the regulation of steroidogenesis associated with acute stress in sturgeon, a cDNA-encoding steroidogenic acute regulatory protein (StAR) was isolated from white sturgeon. The putative amino acid sequence of sturgeon StAR shares high homology (over 60%) with other vertebrates. Phylogenetic analysis grouped sturgeon StAR within Actinopterygii, but it was clearly segregated from teleost StARs. RT-PCR analysis revealed that transcripts were most abundant in yellow corpuscles found throughout the kidney and weaker signals were detected in gonad and kidney. Very weak signals were also detected in brain and spleen by quantitative real-time PCR. In situ hybridization revealed that StAR is expressed in the cells of yellow corpuscles. No significant changes in StAR gene expression were detected in response to an acute handling stress. These results suggest that StAR is highly conserved throughout vertebrates, but the expression of the functional protein during the stress response may be partially regulated post-transcriptionally.

  6. A novel regulatory mechanism of the mitochondrial Ca2+ uniporter revealed by the p38 mitogen-activated protein kinase inhibitor SB202190.

    Science.gov (United States)

    Montero, Mayte; Lobaton, Carmen D; Moreno, Alfredo; Alvarez, Javier

    2002-12-01

    It is widely acknowledged that mitochondrial Ca2+ uptake modulates the cytosolic [Ca2+] ([Ca2+]c) acting as a transient Ca2+ buffer. In addition, mitochondrial [Ca2+] ([Ca2+]M) regulates the rate of respiration and may trigger opening of the permeability transition pore and start apoptosis. However, no mechanism for the physiological regulation of mitochondrial Ca2+ uptake has been described. We show here that SB202190, an inhibitor of p38 mitogen-activated protein (MAP) kinase, strongly stimulates ruthenium red-sensitive mitochondrial Ca2+ uptake, both in intact and in permeabilized HeLa cells. The [Ca2+]M peak induced by agonists was increased about fourfold in the presence of the inhibitor, with a concomitant reduction in the [Ca2+]c peak. The stimulation occurred fast and was rapidly reversible. In addition, experiments in permeabilized cells perfused with controlled [Ca2+] showed that SB202190 stimulated mitochondrial Ca2+ uptake by more than 10-fold, but only in the physiological [Ca2+]c range (1-4 mM). Other structurally related p38 MAP kinase inhibitors (SB203580, PD169316, or SB220025) produced little or no effect. Our data suggest that in HeLa cells, a protein kinase sensitive to SB202190 tonically inhibits the mitochondrial Ca2+ uniporter. This novel regulatory mechanism may be of paramount importance to modulate mitochondrial Ca2+ uptake under different physiopathological conditions.

  7. Dynamic regulation of extracellular signal-regulated kinase (ERK by protein phosphatase 2A regulatory subunit B56γ1 in nuclei induces cell migration.

    Directory of Open Access Journals (Sweden)

    Ei Kawahara

    Full Text Available Extracellular signal-regulated kinase (ERK signalling plays a central role in various biological processes, including cell migration, but it remains unknown what factors directly regulate the strength and duration of ERK activation. We found that, among the B56 family of protein phosphatase 2A (PP2A regulatory subunits, B56γ1 suppressed EGF-induced cell migration on collagen, bound to phosphorylated-ERK, and dephosphorylated ERK, whereas B56α1 and B56β1 did not. B56γ1 was immunolocalized in nuclei. The IER3 protein was immediately highly expressed in response to costimulation of cells with EGF and collagen. Knockdown of IER3 inhibited cell migration and enhanced dephosphorylation of ERK. Analysis of the time course of PP2A-B56γ1 activity following the costimulation showed an immediate loss of phosphatase activity, followed by a rapid increase in activity, and this activity then remained at a stable level that was lower than the original level. Our results indicate that the strength and duration of the nuclear ERK activation signal that is initially induced by ERK kinase (MEK are determined at least in part by modulation of the phosphatase activity of PP2A-B56γ1 through two independent pathways.

  8. Characterization of genes for chitin catabolism in Haloferax mediterranei.

    Science.gov (United States)

    Hou, Jing; Han, Jing; Cai, Lei; Zhou, Jian; Lü, Yang; Jin, Cheng; Liu, Jingfang; Xiang, Hua

    2014-02-01

    Chitin is the second most abundant natural polysaccharide after cellulose. But degradation of chitin has never been reported in haloarchaea. In this study, we revealed that Haloferax mediterranei, a metabolically versatile haloarchaeon, could utilize colloidal or powdered chitin for growth and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) accumulation, and the gene cluster (HFX_5025-5039) for the chitin catabolism pathway was experimentally identified. First, reverse transcription polymerase chain reaction results showed that the expression of the genes encoding the four putative chitinases (ChiAHme, ChiBHme, ChiCHme, and ChiDHme, HFX_5036-5039), the LmbE-like deacetylase (DacHme, HFX_5027), and the glycosidase (GlyAHme, HFX_5029) was induced by colloidal or powdered chitin, and chiA Hme, chiB Hme, and chiC Hme were cotranscribed. Knockout of chiABC Hme or chiD Hme had a significant effect on cell growth and PHBV production when chitin was used as the sole carbon source, and the chiABCD Hme knockout mutant lost the capability to utilize chitin. Knockout of dac Hme or glyA Hme also decreased PHBV accumulation on chitin. These results suggested that ChiABCDHme, DacHme, and GlyAHme were indeed involved in chitin degradation in H. mediterranei. Additionally, the chitinase assay showed that each chitinase possessed hydrolytic activity toward colloidal or powdered chitin, and the major product of colloidal chitin hydrolysis by ChiABCDHme was diacetylchitobiose, which was likely further degraded to monosaccharides by DacHme, GlyAHme, and other related enzymes for both cell growth and PHBV biosynthesis. Taken together, this study revealed the genes and enzymes involved in chitin catabolism in haloarchaea for the first time and indicated the potential of H. mediterranei as a whole-cell biocatalyst in chitin bioconversion.

  9. Role of AtCDC48 & the AtCDC48 Regulatory Protein Family, PUX, in Plant Cell Morphogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Bednarek, Sebastian, Y.

    2009-11-08

    The long-term objective of this work is to understand the molecular events and mechanisms involved in secretory membrane trafficking and organelle biogenesis, which are crucial for normal plant growth and development. Our studies have suggested a vital role for the cytosolic chaperone Cdc48p/p97 during cytokinesis and cell expansion which are highly dependent upon secretory membrane trafficking. Localization studies have shown that the plant Cdc48p/p97, AtCDC48, and the Arabidopsis ortholog of the ER- and Golgi-associated SNARE, syntaxin 5, (referred to as SYP31) are targeted to the division plane during cytokinesis. In addition, AtCDC48 and SYP31 were shown to interact in vitro and in vivo. To characterize further the function of AtCDC48 and SYP31 we have utilized affinity chromatography and MALDI-MS to identify several plant-specific proteins that interact with SYP31 and/or modulate the activity of AtCDC48 including two UBX (i.e. ubiquitin-like) domain containing proteins, PUX1 and PUX2 (Proteins containing UBX domain). These proteins define a plant protein family consisting of 15 uncharacterized members that we postulate interact with AtCDC48. Biochemical studies have demonstrated that PUX2 is a novel membrane adapter for AtCDC48 that mediates AtCDC48/SYP31 interaction and is likely to control AtCDC48-dependent membrane fusion. In contrast, PUX1 negatively regulates AtCDC48 by inhibiting its ATPase activity and by promoting the disassembly of the active hexamer. These findings provide the first evidence that the assembly and disassembly of the CDC48/p97complex is actually a dynamic process. This new unexpected level of regulation for CDC48/p97 was demonstrated to be critical in vivo as pux1 loss-of-function mutants grow faster than wild-type plants. These studies suggest a role for AtCDC48 in plant cell cycle progression including cytokinesis and/or cell expansion. The proposed studies are designed to: 1) characterize further the localization and function of At

  10. Differential association of the Na+/H+ exchanger regulatory factor (NHERF) family of adaptor proteins with the raft- and the non-raft brush border membrane fractions of NHE3

    NARCIS (Netherlands)

    A. Sultan (Ayesha); M. Luo (Ma); Q. Yu (Qingbao); B. Riederer (Beat Michel); W. Xia (Weiliang); M. Chen (Mingmin); S. Lissner (Simone); J.E. Gessner (Johannes); M. Donowitz (Mark); C. Chris Yun (C.); H. deJonge (Hugo); G. Lamprecht (Georg); U. Seidler (Ursula)

    2013-01-01

    textabstractBackground/Aims: Trafficking, brush border membrane (BBM) retention, and signal-specific regulation of the Na+/H+ exchanger NHE3 is regulated by the Na+/H+ Exchanger Regulatory Factor (NHERF) family of PDZ-adaptor proteins, which enable the formation of multiprotein complexes. It is uncl

  11. Regulatory interaction of the Galpha protein with phospholipase A2 in the plasma membrane of Eschscholzia californica.

    Science.gov (United States)

    Heinze, Michael; Steighardt, Jörg; Gesell, Andreas; Schwartze, Wieland; Roos, Werner

    2007-12-01

    Plant heterotrimeric G-proteins are involved in a variety of signaling pathways, though only one alpha and a few betagamma isoforms of their subunits exist. In isolated plasma membranes of California poppy (Eschscholzia californica), the plant-specific Galpha subunit was isolated and identified immunologically and by homology of the cloned gene with that of several plants. In the same membrane, phospholipase A(2) (PLA(2)) was activated by yeast elicitor only if GTPgammaS (an activator of Galpha) was present. From the cholate-solubilized membrane proteins, PLA(2) was co-precipitated together with Galpha by a polyclonal antiserum raised against the recombinant Galpha. In this immunoprecipitate and in the plasma membrane (but not in the Galpha-free supernatant) PLA(2) was stimulated by GTPgammaS. Plasma membranes and immunoprecipitates obtained from antisense transformants with a low Galpha content allowed no such stimulation. An antiserum raised against the C-terminus (which in animal Galphas is located near the target coupling site) precipitated Galpha without any PLA(2) activity. Using non-denaturing PAGE, complexes of solubilized plasma membrane proteins were visualized that contained Galpha plus PLA(2) activity and dissociated at pH 9.5. At this pH, PLA(2) was no longer stimulated by GTPgammaS. It is concluded that a distinct fraction of the plasma membrane-bound PLA(2) exists in a detergent-resistant complex with Galpha that can be dissociated at pH 9.5. This complex allows the Galpha-mediated activation of PLA(2).

  12. Capping protein regulatory cycle driven by CARMIL and V-1 may promote actin network assembly at protruding edges.

    Science.gov (United States)

    Fujiwara, Ikuko; Remmert, Kirsten; Piszczek, Grzegorz; Hammer, John A

    2014-05-13

    Although capping protein (CP) terminates actin filament elongation, it promotes Arp2/3-dependent actin network assembly and accelerates actin-based motility both in vitro and in vivo. In vitro, capping protein Arp2/3 myosin I linker (CARMIL) antagonizes CP by reducing its affinity for the barbed end and by uncapping CP-capped filaments, whereas the protein V-1/myotrophin sequesters CP in an inactive complex. Previous work showed that CARMIL can readily retrieve CP from the CP:V-1 complex, thereby converting inactive CP into a version with moderate affinity for the barbed end. Here we further clarify the mechanism of this exchange reaction, and we demonstrate that the CP:CARMIL complex created by complex exchange slows the rate of barbed-end elongation by rapidly associating with, and dissociating from, the barbed end. Importantly, the cellular concentrations of V-1 and CP determined here argue that most CP is sequestered by V-1 at steady state in vivo. Finally, we show that CARMIL is recruited to the plasma membrane and only at cell edges undergoing active protrusion. Assuming that CARMIL is active only at this location, our data argue that a large pool of freely diffusing, inactive CP (CP:V-1) feeds, via CARMIL-driven complex exchange, the formation of weak-capping complexes (CP:CARMIL) at the plasma membrane of protruding edges. In vivo, therefore, CARMIL should promote Arp2/3-dependent actin network assembly at the leading edge by promoting barbed-end capping there.

  13. HipH Catalyzes the Hydroxylation of 4-Hydroxyisophthalate to Protocatechuate in 2,4-Xylenol Catabolism by Pseudomonas putida NCIMB 9866.

    Science.gov (United States)

    Chao, Hong-Jun; Chen, Yan-Fei; Fang, Ti; Xu, Ying; Huang, Wei E; Zhou, Ning-Yi

    2015-11-13

    In addition to growing on p-cresol, Pseudomonas putida NCIMB 9866 is the only reported strain capable of aerobically growing on 2,4-xylenol, which is listed as a priority pollutant by the U.S. Environmental Protection Agency. Several enzymes involved in the oxidation of the para-methyl group, as well as the corresponding genes, have previously been reported. The enzyme catalyzing oxidation of the catabolic intermediate 4-hydroxyisophthalate to the ring cleavage substrate protocatechuate was also purified from strain NCIMB 9866, but its genetic determinant is still unavailable. In this study, the gene hipH, encoding 4-hydroxyisophthalate hydroxylase, from strain NCIMB 9866 was cloned by transposon mutagenesis. Purified recombinant HipH-His6 was found to be a dimer protein with a molecular mass of approximately 110 kDa. HipH-His6 catalyzed the hydroxylation of 4-hydroxyisophthalate to protocatechuate with a specific activity of 1.54 U mg(-1) and showed apparent Km values of 11.40 ± 3.05 μM for 4-hydroxyisophthalate with NADPH and 11.23 ± 2.43 μM with NADH and similar Km values for NADPH and NADH (64.31 ± 13.16 and 72.76 ± 12.06 μM, respectively). The identity of protocatechuate generated from 4-hydroxyisophthalate hydroxylation by HipH-His6 has also been confirmed by high-performance liquid chromatography and mass spectrometry. Gene transcriptional analysis, gene knockout, and complementation indicated that hipH is essential for 2,4-xylenol catabolism but not for p-cresol catabolism in this strain. This fills a gap in our understanding of the gene that encodes a critical step in 2,4-xylenol catabolism and also provides another example of biochemical and genetic diversity of microbial catabolism of structurally similar compounds.

  14. PuF, an antimetastatic and developmental signaling protein, interacts with the Alzheimer’s amyloid-β precursor protein via a tissue-specific proximal regulatory element (PRE

    Directory of Open Access Journals (Sweden)

    Lahiri Debomoy K

    2013-01-01

    Full Text Available Abstract Background Alzheimer’s disease (AD is intimately tied to amyloid-β (Aβ peptide. Extraneuronal brain plaques consisting primarily of Aβ aggregates are a hallmark of AD. Intraneuronal Aβ subunits are strongly implicated in disease progression. Protein sequence mutations of the Aβ precursor protein (APP account for a small proportion of AD cases, suggesting that regulation of the associated gene (APP may play a more important role in AD etiology. The APP promoter possesses a novel 30 nucleotide sequence, or “proximal regulatory element” (PRE, at −76/−47, from the +1 transcription start site that confers cell type specificity. This PRE contains sequences that make it vulnerable to epigenetic modification and may present a viable target for drug studies. We examined PRE-nuclear protein interaction by gel electrophoretic mobility shift assay (EMSA and PRE mutant EMSA. This was followed by functional studies of PRE mutant/reporter gene fusion clones. Results EMSA probed with the PRE showed DNA-protein interaction in multiple nuclear extracts and in human brain tissue nuclear extract in a tissue-type specific manner. We identified transcription factors that are likely to bind the PRE, using competition gel shift and gel supershift: Activator protein 2 (AP2, nm23 nucleoside diphosphate kinase/metastatic inhibitory protein (PuF, and specificity protein 1 (SP1. These sites crossed a known single nucleotide polymorphism (SNP. EMSA with PRE mutants and promoter/reporter clone transfection analysis further implicated PuF in cells and extracts. Functional assays of mutant/reporter clone transfections were evaluated by ELISA of reporter protein levels. EMSA and ELISA results correlated by meta-analysis. Conclusions We propose that PuF may regulate the APP gene promoter and that AD risk may be increased by interference with PuF regulation at the PRE. PuF is targeted by calcium/calmodulin-dependent protein kinase II inhibitor 1, which also

  15. Connecting two-component regulatory systems by a protein that protects a response regulator from dephosphorylation by its cognate sensor

    OpenAIRE

    Kato, Akinori; Groisman, Eduardo A.

    2004-01-01

    A fundamental question in signal transduction is how an organism integrates multiple signals into a cellular response. Here we report the mechanism by which the Salmonella PmrA/PmrB two-component system responds to the signal controlling the PhoP/PhoQ two-component system. We establish that the PhoP-activated PmrD protein binds to the phosphorylated form of the response regulator PmrA, preventing both its intrinsic dephosphorylation and that promoted by its cognate sensor kinase PmrB. This re...

  16. Regulatory Interactions of Csr Components: the RNA Binding Protein CsrA Activates csrB Transcription in Escherichia coli

    OpenAIRE

    Gudapaty, Seshagirirao; Suzuki, Kazushi; Wang, Xin; Babitzke, Paul; Romeo, Tony

    2002-01-01

    The global regulator CsrA (carbon storage regulator) of Escherichia coli is a small RNA binding protein that represses various metabolic pathways and processes that are induced in the stationary phase of growth, while it activates certain exponential phase functions. Both repression and activation by CsrA involve posttranscriptional mechanisms, in which CsrA binding to mRNA leads to decreased or increased transcript stability, respectively. CsrA also binds to a small untranslated RNA, CsrB, f...

  17. Functional characterization of diverse ring-hydroxylating oxygenases and induction of complex aromatic catabolic gene clusters in Sphingobium sp. PNB

    Directory of Open Access Journals (Sweden)

    Pratick Khara

    2014-01-01

    Full Text Available Sphingobium sp. PNB, like other sphingomonads, has multiple ring-hydroxylating oxygenase (RHO genes. Three different fosmid clones have been sequenced to identify the putative genes responsible for the degradation of various aromatics in this bacterial strain. Comparison of the map of the catabolic genes with that of different sphingomonads revealed a similar arrangement of gene clusters that harbors seven sets of RHO terminal components and a sole set of electron transport (ET proteins. The presence of distinctly conserved amino acid residues in ferredoxin and in silico molecular docking analyses of ferredoxin with the well characterized terminal oxygenase components indicated the structural uniqueness of the ET component in sphingomonads. The predicted substrate specificities, derived from the phylogenetic relationship of each of the RHOs, were examined based on transformation of putative substrates and their structural homologs by the recombinant strains expressing each of the oxygenases and the sole set of available ET proteins. The RHO AhdA1bA2b was functionally characterized for the first time and was found to be capable of transforming ethylbenzene, propylbenzene, cumene, p-cymene and biphenyl, in addition to a number of polycyclic aromatic hydrocarbons. Overexpression of aromatic catabolic genes in strain PNB, revealed by real-time PCR analyses, is a way forward to understand the complex regulation of degradative genes in sphingomonads.

  18. Mechanisms of action of hormone-sensitive lipase in mouse Leydig cells: its role in the regulation of the steroidogenic acute regulatory protein.

    Science.gov (United States)

    Manna, Pulak R; Cohen-Tannoudji, Joëlle; Counis, Raymond; Garner, Charles W; Huhtaniemi, Ilpo; Kraemer, Fredric B; Stocco, Douglas M

    2013-03-22

    Hormone-sensitive lipase (HSL) catalyzes the hydrolysis of cholesteryl esters in steroidogenic tissues and, thus, facilitates cholesterol availability for steroidogenesis. The steroidogenic acute regulatory protein (StAR) controls the rate-limiting step in steroid biosynthesis. However, the modes of action of HSL in the regulation of StAR expression remain obscure. We demonstrate in MA-10 mouse Leydig cells that activation of the protein kinase A (PKA) pathway, by a cAMP analog Bt2cAMP, enhanced expression of HSL and its phosphorylation (P) at Ser-660 and Ser-563, but not at Ser-565, concomitant with increased HSL activity. Phosphorylation and activation of HSL coincided with increases in StAR, P-StAR (Ser-194), and progesterone levels. Inhibition of HSL activity by CAY10499 effectively suppressed Bt2cAMP-induced StAR expression and progesterone synthesis. Targeted silencing of endogenous HSL, with siRNAs, resulted in increased cholesteryl ester levels and decreased cholesterol content in MA-10 cells. Depletion of HSL affected lipoprotein-derived cellular cholesterol influx, diminished the supply of cholesterol to the mitochondria, and resulted in the repression of StAR and P-StAR levels. Cells overexpressing HSL increased the efficacy of liver X receptor (LXR) ligands on StAR expression and steroid synthesis, suggesting HSL-mediated steroidogenesis entails enhanced oxysterol production. Conversely, cells deficient in LXRs exhibited decreased HSL responsiveness. Furthermore, an increase in HSL was correlated with the LXR target genes, steroid receptor element-binding protein 1c and ATP binding cassette transporter A1, demonstrating HSL-dependent regulation of steroidogenesis predominantly involves LXR signaling. LXRs interact/cooperate with RXRs and result in the activation of StAR gene transcription. These findings provide novel insight and demonstrate the molecular events by which HSL acts to drive cAMP/PKA-mediated regulation of StAR expression and

  19. Evolution of hepatic glucose metabolism: liver-specific glucokinase deficiency explained by parallel loss of the gene for glucokinase regulatory protein (GCKR.

    Directory of Open Access Journals (Sweden)

    Zhao Yang Wang

    Full Text Available BACKGROUND: Glucokinase (GCK plays an important role in the regulation of carbohydrate metabolism. In the liver, phosphorylation of glucose to glucose-6-phosphate by GCK is the first step for both glycolysis and glycogen synthesis. However, some vertebrate species are deficient in GCK activity in the liver, despite containing GCK genes that appear to be compatible with function in their genomes. Glucokinase regulatory protein (GCKR is the most important post-transcriptional regulator of GCK in the liver; it participates in the modulation of GCK activity and location depending upon changes in glucose levels. In experimental models, loss of GCKR has been shown to associate with reduced hepatic GCK protein levels and activity. METHODOLOGY/PRINCIPAL FINDINGS: GCKR genes and GCKR-like sequences were identified in the genomes of all vertebrate species with available genome sequences. The coding sequences of GCKR and GCKR-like genes were identified and aligned; base changes likely to disrupt coding potential or splicing were also identified. CONCLUSIONS/SIGNIFICANCE: GCKR genes could not be found in the genomes of 9 vertebrate species, including all birds. In addition, in multiple mammalian genomes, whereas GCKR-like gene sequences could be identified, these genes could not predict a functional protein. Vertebrate species that were previously reported to be deficient in hepatic GCK activity were found to have deleted (birds and lizard or mutated (mammals GCKR genes. Our results suggest that mutation of the GCKR gene leads to hepatic GCK deficiency due to the loss of the stabilizing effect of GCKR.

  20. Subunit architecture of the Golgi Dsc E3 ligase required for sterol regulatory element-binding protein (SREBP) cleavage in fission yeast.

    Science.gov (United States)

    Lloyd, S Julie-Ann; Raychaudhuri, Sumana; Espenshade, Peter J

    2013-07-19

    The membrane-bound sterol regulatory element-binding protein (SREBP) transcription factors regulate lipogenesis in mammalian cells and are activated through sequential cleavage by the Golgi-localized Site-1 and Site-2 proteases. The mechanism of fission yeast SREBP cleavage is less well defined and, in contrast, requires the Golgi-localized Dsc E3 ligase complex. The Dsc E3 ligase consists of five integral membrane subunits, Dsc1 through Dsc5, and resembles membrane E3 ligases that function in endoplasmic reticulum-associated degradation. Using immunoprecipitation assays and blue native electrophoresis, we determined the subunit architecture for the complex of Dsc1 through Dsc5, showing that the Dsc proteins form subcomplexes and display defined connectivity. Dsc2 is a rhomboid pseudoprotease family member homologous to mammalian UBAC2 and a central component of the Dsc E3 ligase. We identified conservation in the architecture of the Dsc E3 ligase and the multisubunit E3 ligase gp78 in mammals. Specifically, Dsc1-Dsc2-Dsc5 forms a complex resembling gp78-UBAC2-UBXD8. Further characterization of Dsc2 revealed that its C-terminal UBA domain can bind to ubiquitin chains but that the Dsc2 UBA domain is not essential for yeast SREBP cleavage. Based on the ability of rhomboid superfamily members to bind transmembrane proteins, we speculate that Dsc2 functions in SREBP recognition and binding. Homologs of Dsc1 through Dsc4 are required for SREBP cleavage and virulence in the human opportunistic pathogen Aspergillus fumigatus. Thus, these studies advance our organizational understanding of multisubunit E3 ligases involved in endoplasmic reticulum-associated degradation and fungal pathogenesis.

  1. Upregulation of Steroidogenic Acute Regulatory Protein by Hypoxia Stimulates Aldosterone Synthesis in Pulmonary Artery Endothelial Cells to Promote Pulmonary Vascular Fibrosis

    Science.gov (United States)

    Maron, Bradley A.; Oldham, William M.; Chan, Stephen Y.; Vargas, Sara O.; Arons, Elena; Zhang, Ying-Yi; Loscalzo, Joseph; Leopold, Jane A.

    2014-01-01

    Background The molecular mechanism(s) regulating hypoxia-induced vascular fibrosis are unresolved. Hyperaldosteronism correlates positively with vascular remodeling in pulmonary arterial hypertension (PAH), suggesting that aldosterone may contribute to the pulmonary vasculopathy of hypoxia. The hypoxia-sensitive transcription factors c-Fos/c-Jun regulate steroidogenic acute regulatory protein (StAR), which facilitates the rate-limiting step of aldosterone steroidogenesis. We hypothesized that c-Fos/c-Jun upregulation by hypoxia activates StAR-dependent aldosterone synthesis in human pulmonary artery endothelial cells (HPAECs) to promote vascular fibrosis in PAH. Methods and Results Patients with PAH, rats with Sugen/hypoxia-PAH, and mice exposed to chronic hypoxia expressed increased StAR in remodeled pulmonary arterioles, providing a basis for investigating hypoxia-StAR signaling in HPAECs. Hypoxia (2.0% FiO2) increased aldosterone levels selectively in HPAECs, which was confirmed by liquid chromatography-mass spectrometry. Increased aldosterone by hypoxia resulted from enhanced c-Fos/c-Jun binding to the proximal activator protein (AP-1) site of the StAR promoter in HPAECs, which increased StAR expression and activity. In HPAECs transfected with StAR-siRNA or treated with the AP-1 inhibitor, SR-11302, hypoxia failed to increase aldosterone, confirming that aldosterone biosynthesis required StAR activation by c-Fos/c-Jun. The functional consequences of aldosterone were confirmed by pharmacological inhibition of the mineralocorticoid receptor with spironolactone or eplerenone, which attenuated hypoxia-induced upregulation of the fibrogenic protein connective tissue growth factor and collagen III in vitro, and decreased pulmonary vascular fibrosis to improve pulmonary hypertension in Conclusions Our findings identify autonomous aldosterone synthesis in HPAECs due to hypoxia-mediated upregulation of StAR as a novel molecular mechanism that promotes pulmonary vascular

  2. Regulatory mechanisms for 3'-end alternative splicing and polyadenylation of the Glial Fibrillary Acidic Protein, GFAP, transcript

    DEFF Research Database (Denmark)

    Blechingberg, Jenny; Lykke-Andersen, Søren; Jensen, Torben Heick;

    2007-01-01

    The glial fibrillary acidic protein, GFAP, forms the intermediate cytoskeleton in cells of the glial lineage. Besides the common GFAP alpha transcript, the GFAP epsilon and GFAP kappa transcripts are generated by alternative mRNA 3'-end processing. Here we use a GFAP minigene to characterize...... molecular mechanisms participating in alternative GFAP expression. Usage of a polyadenylation signal within the alternatively spliced exon 7a is essential to generate the GFAP kappa and GFAP kappa transcripts. The GFAP kappa mRNA is distinct from GFAP epsilon mRNA given that it also includes intron 7a...... with the selection of the exon 7a polyadenylation site being the essential and primary event for regulating GFAP alternative processing. Udgivelsesdato: 2007...

  3. Prostasin and its regulatory proteins in human placentas from pregnant women with preeclampsia and healthy pregnant controls

    DEFF Research Database (Denmark)

    Frederiksen-Møller, Britta; Jørgensen, Jan Stener; Vogel, Lotte Katrine;

    2015-01-01

    for normal placental development in mice. Prostasin is regulated by aldosterone in the kidney and may activate the epithelial sodium channel (ENaC). Preeclampsia is characterized by disturbed placentation, suppression of aldosterone and avid renal sodium retention with hypertension. It was hypothesized...... that preeclampsia is associated with low prostasin expression in placenta and spillover of prostasin into urine across the defect glomerular barrier. METHODS: This hypothesis was addressed in a cross-sectional design with 20 healthy pregnant women and 20 women with new onset of preeclampsia (hypertension and 1......+ for protein on urine dipstick). Blood and urine samples were obtained in relation to delivery and placental biopsies were taken immediately after delivery (control = 39 and preeclampsia 40 weeks). RESULTS: Women with preeclampsia displayed lower levels of aldosterone in plasma (p=0.0475) and in spot urine...

  4. Northwestern profiling of potential translation-regulatory proteins in human breast epithelial cells and malignant breast tissues: evidence for pathological activation of the IGF1R IRES.

    Science.gov (United States)

    Blume, Scott W; Jackson, Nateka L; Frost, Andra R; Grizzle, William E; Shcherbakov, Oleg D; Choi, Hyoungsoo; Meng, Zheng

    2010-06-01

    . Most importantly, we are able to assess the RNA-binding activities of these putative translation-regulatory proteins in primary human breast surgical specimens, and begin to discern positive correlations between individual ITAFs and the malignant phenotype. Together with our previous findings, these new data provide further evidence that pathological dysregulation of IGF1R translational control may contribute to development and progression of human breast cancer, and breast metastasis in particular.

  5. Novel insights into the diversity of catabolic metabolism from ten haloarchaeal genomes.

    Directory of Open Access Journals (Sweden)

    Iain Anderson

    Full Text Available BACKGROUND: The extremely halophilic archaea are present worldwide in saline environments and have important biotechnological applications. Ten complete genomes of haloarchaea are now available, providing an opportunity for comparative analysis. METHODOLOGY/PRINCIPAL FINDINGS: We report here the comparative analysis of five newly sequenced haloarchaeal genomes with five previously published ones. Whole genome trees based on protein sequences provide strong support for deep relationships between the ten organisms. Using a soft clustering approach, we identified 887 protein clusters present in all halophiles. Of these core clusters, 112 are not found in any other archaea and therefore constitute the haloarchaeal signature. Four of the halophiles were isolated from water, and four were isolated from soil or sediment. Although there are few habitat-specific clusters, the soil/sediment halophiles tend to have greater capacity for polysaccharide degradation, siderophore synthesis, and cell wall modification. Halorhabdus utahensis and Haloterrigena turkmenica encode over forty glycosyl hydrolases each, and may be capable of breaking down naturally occurring complex carbohydrates. H. utahensis is specialized for growth on carbohydrates and has few amino acid degradation pathways. It uses the non-oxidative pentose phosphate pathway instead of the oxidative pathway, giving it more flexibility in the metabolism of pentoses. CONCLUSIONS: These new genomes expand our understanding of haloarchaeal catabolic pathways, providing a basis for further experimental analysis, especially with regard to carbohydrate metabolism. Halophilic glycosyl hydrolases for use in biofuel production are more likely to be found in halophiles isolated from soil or sediment.

  6. Catabolic effects of FGF-1 on chondrocytes and its possible role in osteoarthritis.

    Science.gov (United States)

    El-Seoudi, Abdellatif; El Kader, Tarek Abd; Nishida, Takashi; Eguchi, Takanori; Aoyama, Eriko; Takigawa, Masaharu; Kubota, Satoshi

    2017-03-25

    Fibroblast growth factor 1 (FGF-1) is a classical member of the FGF family and is produced by chondrocytes cultured from osteoarthritic patients. Also, this growth factor was shown to bind to CCN family protein 2 (CCN2), which regenerates damaged articular cartilage and counteracts osteoarthritis (OA) in an animal model. However, the pathophysiological role of FGF-1 in cartilage has not been well investigated. In this study, we evaluated the effects of FGF-1 in vitro and its production in vivo by use of an OA model. Treatment of human chondrocytic cells with FGF-1 resulted in marked repression of genes for cartilaginous extracellular matrix components, whereas it strongly induced matrix metalloproteinase 13 (MMP-13), representing its catabolic effects on cartilage. Interestingly, expression of the CCN2 gene was dramatically repressed by FGF-1, which repression eventually caused the reduced production of CCN2 protein from the chondrocytic cells. The results of a reporter gene assay revealed that this repression could be ascribed, at least in part, to transcriptional regulation. In contrast, the gene expression of FGF-1 was enhanced by exogenous FGF-1, indicating a positive feedback system in these cells. Of note, induction of FGF-1 was observed in the articular cartilage of a rat OA model. These results collectively indicate a pathological role of FGF-1 in OA development, which includes an insufficient cartilage regeneration response caused by CCN2 down regulation.

  7. Novel Insights into the Diversity of Catabolic Metabolism from Ten Haloarchaeal Genomes

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Iain; Scheuner, Carmen; Goker, Markus; Mavromatis, Kostas; Hooper, Sean D.; Porat, Iris; Klenk, Hans-Peter; Ivanova, Natalia; Kyrpides, Nikos

    2011-05-03

    The extremely halophilic archaea are present worldwide in saline environments and have important biotechnological applications. Ten complete genomes of haloarchaea are now available, providing an opportunity for comparative analysis. We report here the comparative analysis of five newly sequenced haloarchaeal genomes with five previously published ones. Whole genome trees based on protein sequences provide strong support for deep relationships between the ten organisms. Using a soft clustering approach, we identified 887 protein clusters present in all halophiles. Of these core clusters, 112 are not found in any other archaea and therefore constitute the haloarchaeal signature. Four of the halophiles were isolated from water, and four were isolated from soil or sediment. Although there are few habitat-specific clusters, the soil/sediment halophiles tend to have greater capacity for polysaccharide degradation, siderophore synthesis, and cell wall modification. Halorhabdus utahensis and Haloterrigena turkmenica encode over forty glycosyl hydrolases each, and may be capable of breaking down naturally occurring complex carbohydrates. H. utahensis is specialized for growth on carbohydrates and has few amino acid degradation pathways. It uses the non-oxidative pentose phosphate pathway instead of the oxidative pathway, giving it more flexibility in the metabolism of pentoses. These new genomes expand our understanding of haloarchaeal catabolic pathways, providing a basis for further experimental analysis, especially with regard to carbohydrate metabolism. Halophilic glycosyl hydrolases for use in biofuel production are more likely to be found in halophiles isolated from soil or sediment.

  8. Location and PCR analysis of catabolic genes in a novel Streptomyces sp. DUT_AHX capable of degrading nitrobenzene

    Institute of Scientific and Technical Information of China (English)

    AI Haixin; ZHOU Jiti; LV Hong; WANG Jing; GUO Jianbo; LIU Guangfei; QU Yuanyuan

    2008-01-01

    A novel strain of Streptomyces sp. DUT_AHX was isolated from sludge contaminated with nitrobenzene and identified on the basis of physiological and biochemical tests and 16S ribosomal DNA (rDNA) sequence analysis. The optimal degradation conditions were as follows: temperature 30℃, pH 7.0-8.0, shaking speed 150-180 r/min and inocula 10% (V/V). The strain, which possessed a partial reductive pathway with the release of ammonia, was also able to grow on mineral salts basal (MSB) medium plates with 2-aminophenol, phenol, or toluene as the sole carbon source. Furthermore, the enzyme activity tests showed crude extracts of nitrobenzene-grown DUT_AHX contained 2-aminophenol 1,6-dioxygenase activity. The 17-kb plasmid was isolated by the modified alkaline lysis method and was further cured by sodium dodecyl sulphate (SDS) together with 37℃. As a result, the cured derivative strain DUT_AHX-4 lost the 2-aminophenol 1,6-dioxygenase activity. The results suggested that the catabolic genes encoding the nitrobenzene-degrading enzymes were plasmid-associated. Moreover, the plasmid DNA was amplified with degenerate primers by touchdown PCR and an expected size fragment (471 bp) was generated. The Blast results revealed that the gene encoding a 157 amino acid polypeptide was 39% to 76% identical to YHS domain protein. The further examination of the plasmid would demonstrate the molecular basis of nitrobenzene catabolism in Streptomyces, such as regulation and genetic organization of the catabolic genes.

  9. The CD47-signal regulatory protein alpha (SIRPa) interaction is a therapeutic target for human solid tumors.

    Science.gov (United States)

    Willingham, Stephen B; Volkmer, Jens-Peter; Gentles, Andrew J; Sahoo, Debashis; Dalerba, Piero; Mitra, Siddhartha S; Wang, Jian; Contreras-Trujillo, Humberto; Martin, Robin; Cohen, Justin D; Lovelace, Patricia; Scheeren, Ferenc A; Chao, Mark P; Weiskopf, Kipp; Tang, Chad; Volkmer, Anne Kathrin; Naik, Tejaswitha J; Storm, Theresa A; Mosley, Adriane R; Edris, Badreddin; Schmid, Seraina M; Sun, Chris K; Chua, Mei-Sze; Murillo, Oihana; Rajendran, Pradeep; Cha, Adriel C; Chin, Robert K; Kim, Dongkyoon; Adorno, Maddalena; Raveh, Tal; Tseng, Diane; Jaiswal, Siddhartha; Enger, Per Øyvind; Steinberg, Gary K; Li, Gordon; So, Samuel K; Majeti, Ravindra; Harsh, Griffith R; van de Rijn, Matt; Teng, Nelson N H; Sunwoo, John B; Alizadeh, Ash A; Clarke, Michael F; Weissman, Irving L

    2012-04-24

    CD47, a "don't eat me" signal for phagocytic cells, is expressed on the surface of all human solid tumor cells. Analysis of patient tumor and matched adjacent normal (nontumor) tissue revealed that CD47 is overexpressed on cancer cells. CD47 mRNA expression levels correlated with a decreased probability of survival for multiple types of cancer. CD47 is a ligand for SIRPα, a protein expressed on macrophages and dendritic cells. In vitro, blockade of CD47 signaling using targeted monoclonal antibodies enabled macrophage phagocytosis of tumor cells that were otherwise protected. Administration of anti-CD47 antibodies inhibited tumor growth in orthotopic immunodeficient mouse xenotransplantation models established with patient tumor cells and increased the survival of the mice over time. Anti-CD47 antibody therapy initiated on larger tumors inhibited tumor growth and prevented or treated metastasis, but initiation of the therapy on smaller tumors was potentially curative. The safety and efficacy of targeting CD47 was further tested and validated in immune competent hosts using an orthotopic mouse breast cancer model. These results suggest all human solid tumor cells require CD47 expression to suppress phagocytic innate immune surveillance and elimination. These data, taken together with similar findings with other human neoplasms, show that CD47 is a commonly expressed molecule on all cancers, its function to block phagocytosis is known, and blockade of its function leads to tumor cell phagocytosis and elimination. CD47 is therefore a validated target for cancer therapies.

  10. The effects of acetaldehyde and acrolein on muscle catabolism in C2 myotubes.

    Science.gov (United States)

    Rom, Oren; Kaisari, Sharon; Aizenbud, Dror; Reznick, Abraham Z

    2013-12-01

    The toxic aldehydes acetaldehyde and acrolein were previously suggested to damage skeletal muscle. Several conditions in which exposure to acetaldehyde and acrolein is increased were associated with muscle wasting and dysfunction. These include alcoholic myopathy, renal failure, oxidative stress, and inflammation. A main exogenous source of both acetaldehyde and acrolein is cigarette smoking, which was previously associated with increased muscle catabolism. Recently, we have shown that exposure of skeletal myotubes to cigarette smoke stimulated muscle catabolism via increased oxidative stress, activation of p38 MAPK, and upregulation of muscle-specific E3 ubiquitin ligases. In this study, we aimed to investigate the effects of acetaldehyde and acrolein on catabolism of skeletal muscle. Skeletal myotubes differentiated from the C2 myoblast cell line were exposed to acetaldehyde or acrolein and their effects on signaling pathways related to muscle catabolism were studied. Exposure of myotubes to acetaldehyde did not promote muscle catabolism. However, exposure to acrolein caused increased generation of free radicals, activation of p38 MAPK, upregulation of the muscle-specific E3 ligases atrogin-1 and MuRF1, degradation of myosin heavy chain, and atrophy of myotubes. Inhibition of p38 MAPK by SB203580 abolished acrolein-induced muscle catabolism. Our findings demonstrate that acrolein but not acetaldehyde activates a signaling cascade resulting in muscle catabolism in skeletal myotubes. Although within the limitations of an in vitro study, these findings indicate that acrolein may promote muscle wasting in conditions of increased exposure to this aldehyde.

  11. Biomimetic molecules lower catabolic expression and prevent chondroitin sulfate degradation in an osteoarthritic ex vivo model.

    Science.gov (United States)

    Sharma, Shaili; Vazquez-Portalatin, Nelda; Calve, Sarah; Panitch, Alyssa

    2016-02-08

    Aggrecan, the major proteoglycan in cartilage, serves to protect cartilage tissue from damage and degradation during the progression of osteoarthritis (OA). In cartilage extracellular matrix (ECM) aggrecan exists in an aggregate composed of several aggrecan molecules that bind to a single filament of hyaluronan. Each molecule of aggrecan is composed of a protein core and glycosaminoglycan sides chains, the latter of which provides cartilage with the ability to retain water and resist compressive loads. During the progression of OA, loss of aggrecan is considered to occur first, after which other cartilage matrix components become extremely susceptible to degradation. Proteolytic cleavage of the protein core of aggrecan by enzymes such as aggrecanases, prevent its binding to HA and lower cartilage mechanical strength. Here we present the use of HA-binding or collagen type II-binding molecules that functionally mimic aggrecan but lack known cleavage sites, protecting the molecule from proteolytic degradation. These molecules synthesized with chondroitin sulfate backbones conjugated to hyaluronan- or collagen type II- binding peptides, are capable of diffusing through a cartilage explant and adhering to the ECM of this tissue. The objective of this study was to test the functional efficacy of these molecules in an ex vivo osteoarthritic model to discern the optimal molecule for further studies. Different variations of chondroitin sulfate conjugated to the binding peptides were diffused through aggrecan depleted explants and assessed for their ability to enhance compressive stiffness, prevent CS degradation, and modulate catabolic (MMP-13 and ADAMTS-5) and anabolic (aggrecan and collagen type II) gene expression. A pilot in vivo study assessed the ability to retain the molecule within the joint space of an osteoarthritic guinea pig model. The results indicate chondroitin sulfate conjugated to hyaluronan-binding peptides is able to significantly restore equilibrium

  12. Expression of Angiogenesis Regulatory Proteins and Epithelial-Mesenchymal Transition Factors in Platelets of the Breast Cancer Patients

    Directory of Open Access Journals (Sweden)

    Hui Han

    2014-01-01

    Full Text Available Platelets play a role in tumor angiogenesis and growth and are the main transporters of several angiogenesis regulators. Here, we aimed to determine the levels of angiogenesis regulators and epithelial-mesenchymal transition factors sequestered by circulating platelets in breast cancer patients and age-matched healthy controls. Platelet pellets (PP and platelet-poor plasma (PPP were collected by routine protocols. Vascular endothelial growth factor (VEGF, platelet-derived growth factor BB (PDGF-BB, thrombospondin-1 (TSP-1, platelet factor 4 (PF4, and transforming growth factor-β1 (TGF-β1 were measured by enzyme-linked immunosorbent assay. Angiogenesis-associated expression of VEGF (2.1 pg/106 platelets versus 0.9 pg/106 platelets, P < 0.001, PF4 (21.2 ng/106 platelets versus 10.2 ng/106 platelets, P < 0.001, PDGF-BB (42.9 pg/106 platelets versus 19.1 pg/106 platelets, P < 0.001, and TGF-β1 (15.3 ng/106 platelets versus 4.3 ng/106 platelets, P < 0.001 differed in the PP samples of cancer and control subjects. In addition, protein concentrations were associated with clinical characteristics (P<0.05. Circulating platelets in breast cancer sequester higher levels of PF4, VEGF, PDGF-BB, and TGF-β1, suggesting a possible target for early diagnosis. VEGF, PDGF, and TGF-β1 concentrations in platelets may be associated with prognosis.

  13. Clonorchis sinensis-derived total protein attenuates airway inflammation in murine asthma model by inducing regulatory T cells and modulating dendritic cell functions

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Young-Il [Div. of Malaria and Parasitic Diseases, Korea Centers for Disease Control and Prevention, Osong (Korea, Republic of); Kim, Seung Hyun [Div. of AIDS, National Institute of Health, Korea Centers for Disease Control and Prevention, Osong (Korea, Republic of); Ju, Jung Won; Cho, Shin Hyeong; Lee, Won Ja [Div. of Malaria and Parasitic Diseases, Korea Centers for Disease Control and Prevention, Osong (Korea, Republic of); Park, Jin Wook; Park, Yeong-Min [Dept. of Microbiology and Immunology, College of Medicine, Pusan National University, Yang-San (Korea, Republic of); Lee, Sang Eun, E-mail: ondalgl@cdc.go.kr [Div. of Malaria and Parasitic Diseases, Korea Centers for Disease Control and Prevention, Osong (Korea, Republic of)

    2011-04-22

    Highlights: {yields} Treatment with Clonorchis sinensis-derived total protein attenuates OVA-induced airway inflammation and AHR to methacholine. {yields} Induction of CD4{sup +}CD25{sup +}Foxp3{sup +} T cells and IL-10 along with suppression of splenocyte proliferation by C. sinensis-derived total protein. {yields} C. sinensis-derived total protein interferes with the expression of co-stimulatory molecules in DCs. -- Abstract: Asthma is characterized by Th2-mediated inflammation, resulting in airway hyperresponsiveness (AHR) through airway remodeling. Recent epidemiological and experimental reports have suggested an inverse relationship between the development of allergy and helminth infections. Infection by Clonorchis sinensis, a liver fluke that resides in the bile duct of humans, is endemic predominantly in Asia including Korea and China. Using a murine model for asthma, we investigated the effects of C. sinensis-derived total protein (Cs-TP) on allergen-induced airway inflammation and the mechanism underlying the protective effects of Cs-TP administration on asthma. Treatment with Cs-TP attenuated OVA-induced airway inflammation and methacholine-induced AHR, as well as eosinophilia development, lymphocyte infiltration into the lung, and goblet cell metaplasia. This protective effect of Cs-TP is associated with markedly reduced OVA-specific IgE and Th1/Th2 cytokine production. Moreover, Cs-TP increased the number of CD4{sup +}CD25{sup +}Foxp3{sup +} regulatory T (Treg) cells as well as their suppressive activity. In fact, proliferation of OVA-restimulated splenocytes was suppressed significantly. Cs-TP also inhibited the expression of such co-stimulatory molecules as CD80, CD86, and CD40 in LPS- or OVA-stimulated dendritic cells (DCs), suggesting that Cs-TP could interfere with the capacity of airway DCs to prime naive T cells. These data demonstrate the capacity of C. sinensis to ameliorate allergic asthma and broaden our understanding of the paradoxical

  14. Arctigenin induces cell cycle arrest by blocking the phosphorylation of Rb via the modulation of cell cycle regulatory proteins in human gastric cancer cells.

    Science.gov (United States)

    Jeong, Jin Boo; Hong, Se Chul; Jeong, Hyung Jin; Koo, Jin Suk

    2011-10-01

    Gastric cancer is a leading cause of cancer-related deaths, worldwide being second only to lung cancer as a cause of death. Arctigenin, a representative dibenzylbutyrolactone lignan, occurs in a variety of plants. However, the molecular mechanisms of arctigenin for anti-tumor effect on gastric cancer have not been examined. This study examined the biological effects of arctigenin on the human gastric cancer cell line SNU-1 and AGS. Cell proliferation was determined by MTT assay. In MTT assay, the proliferation of SNU-1 and AGS cells was significantly inhibited by arctigenin in a time and dose dependent manner, as compared with SNU-1 and AGS cells cultured in the absence of arctigenin. Inhibition of cell proliferation by arctigenin was in part associated with apoptotic cell death, as shown by changes in the expression ratio of Bcl-2 to Bax by arctigenin. Also, arctigenin blocked cell cycle arrest from G(1) to S phase by regulating the expression of cell cycle regulatory proteins such as Rb, cyclin D1, cyclin E, CDK4, CDK2, p21Waf1/Cip1 and p15 INK4b. The antiproliferative effect of arctigenin on SNU-1 and AGS gastric cancer cells revealed in this study suggests that arctigenin has intriguing potential as a chemopreventive or chemotherapeutic agent.

  15. A Feedback Regulatory Loop between G3P and Lipid Transfer Proteins DIR1 and AZI1 Mediates Azelaic-Acid-Induced Systemic Immunity

    Directory of Open Access Journals (Sweden)

    Keshun Yu

    2013-04-01

    Full Text Available Systemic acquired resistance (SAR, a highly desirable form of plant defense, provides broad-spectrum immunity against diverse pathogens. The recent identification of seemingly unrelated chemical inducers of SAR warrants an investigation of their mutual interrelationships. We show that SAR induced by the dicarboxylic acid azelaic acid (AA requires the phosphorylated sugar derivative glycerol-3-phosphate (G3P. Pathogen inoculation induced the release of free unsaturated fatty acids (FAs and thereby triggered AA accumulation, because these FAs serve as precursors for AA. AA accumulation in turn increased the levels of G3P, which is required for AA-conferred SAR. The lipid transfer proteins DIR1 and AZI1, both of which are required for G3P- and AA-induced SAR, were essential for G3P accumulation. Conversely, reduced G3P resulted in decreased AZI1 and DIR1 transcription. Our results demonstrate that an intricate feedback regulatory loop among G3P, DIR1, and AZI1 regulates SAR and that AA functions upstream of G3P in this pathway.

  16. β-Hydroxybutyrate Facilitates Fatty Acids Synthesis Mediated by Sterol Regulatory Element-Binding Protein1 in Bovine Mammary Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Min Zhang

    2015-11-01

    Full Text Available Background/Aims: In dairy cows, β-hydroxybutyrate (BHBA is utilized as precursors of de novo synthesized fatty acids in mammary gland. Ketotic cows are characterized by excessive negative energy balance (NEB, which can further increase the blood BHBA concentration. Sterol regulatory element-binding protein1 (SREBP1 and cell death-inducing DNA fragmentation factor-alpha-like effector α (Cidea play crucial roles in lipid synthesis. Therefore, we hypothesized that BHBA could stimulate SREBP1/Cidea pathway to increase milk fat synthesis in bovine mammary epithelial cells. Methods: Bovine mammary epithelial cells were treated with different concentrations of BHBA and transfected with adenovirus to silence SREBP1 expression. The effects of BHBA on the lipid synthesis in bovine mammary epithelial cells were investigated. Results: The results showed that BHBA could significantly increase the expression of SREBP1, fatty acid synthase (FAS, acetyl-CoA carboxylase α (ACC-α, Cidea and diacylglycerol transferase-1 (DGAT-1, as well as the triglycerides (TG content in bovine mammary epithelial cells. BHBA treatment also increased the transfer of mature SREBP1 to nucleus compared with control group. However, SREBP1 silencing could significantly down-regulate the overexpression of FAS, ACC-α, Cidea and DGAT-1, as well as TG content induced by BHBA. Conclusion: The present data indicate that BHBA can significantly increase TG secretion mediated by SREBP1 in bovine mammary epithelial cells.

  17. Expression of steroidogenic acute regulatory protein (StAR) in male American bullfrog (Rana catesbeiana) and preliminary evaluation of the response to TNT.

    Science.gov (United States)

    Paden, Norka E; Carr, James A; Kendall, Ronald J; Wages, Mike; Smith, Ernest E

    2010-06-01

    We examined the expression of steroidogenic acute regulatory (StAR) protein mRNA in the American bullfrog (Rana catesbeiana). Primers and probes were designed to obtain a partial sequence of bullfrog StAR cDNA consisting of 349 base pairs. Quantitative PCR analysis of StAR mRNA equivalents was performed in tissues of juvenile and adult bullfrogs. In this study 18S mRNA was used as an internal standard. There were no differences in the expression of 18S RNA among tissues or between age groups. In juvenile males, the rank order for the constitutive levels of StAR was testes>skin>brain>kidneys. In adult males, StAR mRNA equivalent was greatest in testes, followed by kidneys, brain, and skin. In addition, stimulation and induction of testicular StAR by human chorionic gonadotropin significantly increased expression of StAR at 2, 4, and 6h after injection. Preliminary evaluation of 2, 4, 6-trinitrotoluene (TNT) revealed that acute exposure is associated with reduction of StAR mRNA expression. The information provided in this study will be useful for future research on StAR gene expression in amphibian reproductive biology and the development of reproductive biomarkers.

  18. Early graft failure of GalTKO pig organs in baboons is reduced by expression of a human complement pathway-regulatory protein.

    Science.gov (United States)

    Azimzadeh, Agnes M; Kelishadi, Sean S; Ezzelarab, Mohamed B; Singh, Avneesh K; Stoddard, Tiffany; Iwase, Hayato; Zhang, Tianshu; Burdorf, Lars; Sievert, Evelyn; Avon, Chris; Cheng, Xiangfei; Ayares, David; Horvath, Keith A; Corcoran, Philip C; Mohiuddin, Muhammad M; Barth, Rolf N; Cooper, David K C; Pierson, Richard N

    2015-01-01

    We describe the incidence of early graft failure (EGF, defined as loss of function from any cause within 3 days after transplant) in a large cohort of GalTKO pig organs transplanted into baboons in three centers, and the effect of additional expression of a human complement pathway-regulatory protein, CD46 or CD55 (GalTKO.hCPRP). Baboon recipients of life-supporting GalTKO kidney (n = 7) or heterotopic heart (n = 14) grafts received either no immunosuppression (n = 4), or one of several partial or full immunosuppressive regimens (n = 17). Fourteen additional baboons received a GalTKO.hCPRP kidney (n = 5) or heart (n = 9) and similar treatment regimens. Immunologic, pathologic, and coagulation parameters were measured at frequent intervals. EGF of GalTKO organs occurred in 9/21 baboons (43%). hCPRP expression reduced the GalTKO EGF incidence to 7% (1/14; P organs in which EGF developed (P organ failure, and (iii) the expression of a hCPRP reduces EGF but does not prevent systemic coagulation activation. Additional strategies will be required to control coagulation activation.

  19. The effect of high glucose levels on the hypermethylation of protein phosphatase 1 regulatory subunit 3C (PPP1R3C) gene in colorectal cancer

    Indian Academy of Sciences (India)

    Soo Kyung Lee; Ji Wook Moon; Yong Woo Lee; Jung Ok Lee; Su Jin Kim; Nami Kim; Jin Kim; Hyeon Soo Kim; Sun-Hwa Park

    2015-03-01

    DNA methylation is an epigenetic event that occurs frequently in colorectal cancer (CRC). Increased glucose level is a strong risk factor for CRC. Protein phosphatase 1 regulatory subunit 3C (PPP1R3C) modulates glycogen metabolism, particularly glycogen synthesis. The aim of this study was to investigate the effect of high glucose levels on DNA methylation of PPP1R3C in CRC. PPP1R3C was significantly hypermethylated in CRC tissues (76/105, 72.38%, < 0.05) and colon cancer cell lines ( < 0.05). CRC tissues obtained from patients with high glucose levels showed that the methylation of PPP1R3C was lower than in patients who had normal levels of glucose. When DLD-1 cells were cultured under conditions of high glucose, the methylation of PPP1R3C was repressed. The expression of PPP1R3C was inversely related to methylation status. In addition, a promoter luciferase assay showed that the transcriptional activity of PPP1R3C was increased in high glucose culture conditions. The number of cells decreased when PPP1R3C was silenced in DLD-1 cells. These results suggest that PPP1R3C, a novel hypermethylated gene in CRC, may play a critical role in cancer cell growth in association with glucose levels.

  20. Modulation of glucokinase by glucose, small-molecule activator and glucokinase regulatory protein: steady-state kinetic and cell-based analysis.

    Science.gov (United States)

    Bourbonais, Francis J; Chen, Jing; Huang, Cong; Zhang, Yanwei; Pfefferkorn, Jeffrey A; Landro, James A

    2012-02-01

    GK (glucokinase) is an enzyme central to glucose metabolism that displays positive co-operativity to substrate glucose. Small-molecule GKAs (GK activators) modulate GK catalytic activity and glucose affinity and are currently being pursued as a treatment for Type 2 diabetes. GK progress curves monitoring product formation are linear up to 1 mM glucose, but biphasic at 5 mM, with the transition from the lower initial velocity to the higher steady-state velocity being described by the rate constant kact. In the presence of a liver-specific GKA (compound A), progress curves at 1 mM glucose are similar to those at 5 mM, reflecting activation of GK by compound A. We show that GKRP (GK regulatory protein) is a slow tight-binding inhibitor of GK. Analysis of progress curves indicate that this inhibition is time dependent, with apparent initial and final Ki values being 113 and 12.8 nM respectively. When GK is pre-incubated with glucose and compound A, the inhibition observed by GKRP is time dependent, but independent of GKRP concentration, reflecting the GKA-controlled transition between closed and open GK conformations. These data are supported by cell-based imaging data from primary rat hepatocytes. This work characterizes the modulation of GK by a novel GKA that may enable the design of new and improved GKAs.

  1. Prominent 85-kDa oligomannosidic glycoproteins of rat brain are signal regulatory proteins and include the SHP substrate-1 for tyrosine phosphatases.

    Science.gov (United States)

    Bartoszewicz, Z P; Jaffe, H; Sasaki, M; Möller, J R; Stebbins, J W; Gebrekristos, H; Quarles, R H

    1999-04-01

    The glycoprotein component in rat brain reacting most strongly with Galanthus nivalis agglutinin (GNA) on western blots migrates as an 85-kDa band. GNA identifies mannose-rich oligosaccharides because it is highly specific for terminal alpha-mannose residues. After purification of this 85-kDa glycoprotein band by chromatography on GNA-agarose and preparative gel electrophoresis, binding of other lectins demonstrated the presence of fucose and a trace of galactose, but no sialic acid. Treatment with N-Glycanase or endoglycosidase H produced a 65-kDa band, indicating that it consisted of about one-fourth N-linked oligomannosidic carbohydrate moieties. High-performance anion-exchange chromatography and fluorescence-assisted carbohydrate electrophoresis indicated that the major carbohydrate moiety is a heptasaccharide with the structure Manalpha1-6(Manalpha1-3)Manalpha1-6(Manalpha1-3) Manbeta1-4Glc-NAcbeta1-4GlcNAc (Man5GlcNAc2). Determination of amino acid sequences of peptides produced by endoproteinase digestion demonstrated that this 85-kDa mannose-rich glycoprotein component contained the SHP substrate-1 for phosphotyrosine phosphatases and at least one other member of the signal-regulatory protein (SIRP) family. The unusually high content of oligomannosidic carbohydrate moieties on these receptor-like members of the immunoglobulin superfamily in neural tissue could be of functional significance for intercellular adhesion or signaling.

  2. Site-directed mutagenesis of the cAMP-binding sites of the recombinant type I regulatory subunit of cAMP-dependent protein kinase.

    Science.gov (United States)

    Kuno, T; Shuntoh, H; Sakaue, M; Saijoh, K; Takeda, T; Fukuda, K; Tanaka, C

    1988-06-30

    The type I regulatory subunit (R-I) of rat brain cAMP-dependent protein kinase was expressed in E. coli and site-directed mutagenesis was used to substitute amino acids in the putative cAMP-binding sites. The wild-type recombinant R-I bound 2 mol of cAMP/mol subunit, while two mutant R-Is with a single amino acid substitution in one of the two intrachain cAMP-binding sites (clone N153:a glutamate for Gly-200, and clone C254:an aspartate for Gly-324) bound 1 mol of cAMP/mol subunit. When these two substitutions were made in one mutant, cAMP did not bind to this mutant, indicating that binding of cAMP to N153 or C254 was to their nonmutated sites. Competition experiments with site-selective analogs and dissociation of bound cAMP from mutant R-Is provided evidence for strong intrachain interactions between the two classes of cAMP-binding sites in R-I.

  3. The zinc finger protein ZNF658 regulates the transcription of genes involved in zinc homeostasis and affects ribosome biogenesis through the zinc transcriptional regulatory element.

    Science.gov (United States)

    Ogo, Ogo A; Tyson, John; Cockell, Simon J; Howard, Alison; Valentine, Ruth A; Ford, Dianne

    2015-03-01

    We previously identified the ZTRE (zinc transcriptional regulatory element) in genes involved in zinc homeostasis and showed that it mediates transcriptional repression in response to zinc. We now report that ZNF658 acts at the ZTRE. ZNF658 was identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry of a band excised after electrophoretic mobility shift assay using a ZTRE probe. The protein contains a KRAB domain and 21 zinc fingers. It has similarity with ZAP1 from Saccharomyces cerevisiae, which regulates the response to zinc restriction, including a conserved DNA binding region we show to be functional also in ZNF658. Small interfering RNA (siRNA) targeted to ZNF658 abrogated the zinc-induced, ZTRE-dependent reduction in SLC30A5 (ZnT5 gene), SLC30A10 (ZnT10 gene), and CBWD transcripts in human Caco-2 cells and the ability of zinc to repress reporter gene expression from corresponding promoter-reporter constructs. Microarray analysis of the effect of reducing ZNF658 expression by siRNA uncovered a large decrease in rRNA. We find that ZTREs are clustered within the 45S rRNA precursor. We also saw effects on expression of multiple ribosomal proteins. ZNF658 thus links zinc homeostasis with ribosome biogenesis, the most active transcriptional, and hence zinc-demanding, process in the cell. ZNF658 is thus a novel transcriptional regulator that plays a fundamental role in the orchestrated cellular response to zinc availability.

  4. Compressive stress induces dephosphorylation of the myosin regulatory light chain via RhoA phosphorylation by the adenylyl cyclase/protein kinase A signaling pathway.

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    Kenji Takemoto

    Full Text Available Mechanical stress that arises due to deformation of the extracellular matrix (ECM either stretches or compresses cells. The cellular response to stretching has been actively studied. For example, stretching induces phosphorylation of the myosin regulatory light chain (MRLC via the RhoA/RhoA-associated protein kinase (ROCK pathway, resulting in increased cellular tension. In contrast, the effects of compressive stress on cellular functions are not fully resolved. The mechanisms for sensing and differentially responding to stretching and compressive stress are not known. To address these questions, we investigated whether phosphorylation levels of MRLC were affected by compressive stress. Contrary to the response in stretching cells, MRLC was dephosphorylated 5 min after cells were subjected to compressive stress. Compressive loading induced activation of myosin phosphatase mediated via the dephosphorylation of myosin phosphatase targeting subunit 1 (Thr853. Because myosin phosphatase targeting subunit 1 (Thr853 is phosphorylated only by ROCK, compressive loading may have induced inactivation of ROCK. However, GTP-bound RhoA (active form increased in response to compressive stress. The compression-induced activation of RhoA and inactivation of its effector ROCK are contradictory. This inconsistency was due to phosphorylation of RhoA (Ser188 that reduced affinity of RhoA to ROCK. Treatment with the inhibitor of protein kinase A that phosphorylates RhoA (Ser188 induced suppression of compression-stimulated MRLC dephosphorylation. Incidentally, stretching induced phosphorylation of MRLC, but did not affect phosphorylation levels of RhoA (Ser188. Together, our results suggest that RhoA phosphorylation is an important process for MRLC dephosphorylation by compressive loading, and for distinguishing between stretching and compressing cells.

  5. Progesterone stimulates adipocyte determination and differentiation 1/sterol regulatory element-binding protein 1c gene expression. potential mechanism for the lipogenic effect of progesterone in adipose tissue.

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    Lacasa, D; Le Liepvre, X; Ferre, P; Dugail, I

    2001-04-13

    Fatty acid synthase (FAS), a nutritionally regulated lipogenic enzyme, is transcriptionally controlled by ADD1/SREBP1c (adipocyte determination and differentiation 1/sterol regulatory element-binding protein 1c), through insulin-mediated stimulation of ADD1/SREBP1c expression. Progesterone exerts lipogenic effects on adipocytes, and FAS is highly induced in breast tumor cell lines upon progesterone treatment. We show here that progesterone up-regulates ADD1/SREBP1c expression in the MCF7 breast cancer cell line and the primary cultured preadipocyte from rat parametrial adipose tissue. In MCF7, progesterone induced ADD1/SREBP1c and Metallothionein II (a well known progesterone-regulated gene) mRNAs, with comparable potency. In preadipocytes, progesterone increased ADD1/SREBP1c mRNA dose-dependently, but not SREBP1a or SREBP2. Run-on experiments demonstrated that progesterone action on ADD1/SREBP1c was primarily at the transcriptional level. The membrane-bound and mature nuclear forms of ADD1/SREBP1 protein accumulated in preadipocytes cultured with progesterone, and FAS induction could be abolished by adenovirus-mediated overexpression of a dominant negative form of ADD1/SREBP1 in these cells. Finally, in the presence of insulin, progesterone was unable to up-regulate ADD1/SREBP1c mRNA in preadipocytes, whereas its effect was restored after 24 h of insulin deprivation. Together these results demonstrate that ADD1/SREBP1c is controlled by progesterone, which, like insulin, acts by increasing ADD1/SREBP1c gene transcription. This provides a potential mechanism for the lipogenic actions of progesterone on adipose tissue.

  6. Foot-and-mouth disease virus leader proteinase inhibits dsRNA-induced type I interferon transcription by decreasing interferon regulatory factor 3/7 in protein levels

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    Wang, Dang; Fang, Liurong; Luo, Rui; Ye, Rui; Fang, Ying; Xie, Lilan; Chen, Huanchun [Division of Animal Infectious Diseases, State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070 (China); Xiao, Shaobo, E-mail: shaoboxiao@yahoo.com [Division of Animal Infectious Diseases, State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070 (China)

    2010-08-13

    Research highlights: {yields} FMDV L{sup pro} inhibits poly(I:C)-induced IFN-{alpha}1/{beta} mRNA expression. {yields} L{sup pro} inhibits MDA5-mediated activation of the IFN-{alpha}1/{beta} promoter. {yields} L{sup pro} significantly reduced the transcription of multiple IRF-responsive genes. {yields} L{sup pro} inhibits IFN-{alpha}1/{beta} promoter activation by decreasing IRF-3/7 in protein levels. {yields} The ability to process eIF-4G of L{sup pro} is not necessary to inhibit IFN-{alpha}1/{beta} activation. -- Abstract: The leader proteinase (L{sup pro}) of foot-and-mouth disease virus (FMDV) has been identified as an interferon-{beta} (IFN-{beta}) antagonist that disrupts the integrity of transcription factor nuclear factor {kappa}B (NF-{kappa}B). In this study, we showed that the reduction of double stranded RNA (dsRNA)-induced IFN-{alpha}1/{beta} expression caused by L{sup pro} was also associated with a decrease of interferon regulatory factor 3/7 (IRF-3/7) in protein levels, two critical transcription factors for activation of IFN-{alpha}/{beta}. Furthermore, overexpression of L{sup pro} significantly reduced the transcription of multiple IRF-responsive genes including 2',5'-OAS, ISG54, IP-10, and RANTES. Screening L{sup pro} mutants indicated that the ability to process eIF-4G of L{sup pro} is not required for suppressing dsRNA-induced activation of the IFN-{alpha}1/{beta} promoter and decreasing IRF-3/7 expression. Taken together, our results demonstrate that, in addition to disrupting NF-{kappa}B, L{sup pro} also decreases IRF-3/7 expression to suppress dsRNA-induced type I IFN production, suggesting multiple strategies used by FMDV to counteract the immune response to viral infection.

  7. Involvement of NF-κB and muscle specific E3 ubiquitin ligase MuRF1 in cigarette smoke-induced catabolism in C2 myotubes.

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    Kaisari, Sharon; Rom, Oren; Aizenbud, Dror; Reznick, Abraham Z

    2013-01-01

    Cigarette smoking has been identified as a risk factor for muscular damage and sarcopenia, the age-related loss of muscle mass and strength in old age. Cigarette smoke (CS)-induced oxidative stress and p38 MAPK activation have been shown to be the main cellular mechanisms leading to skeletal muscle catabolism. In order to investigate the involvement of NF-κB as another possible cellular mechanism by which CS promotes muscle catabolism, C2 myotubes, from an in vitro skeletal muscle cell line, were exposed to different time periods of whole vapor phase CS in the presence or absence of NF-κB inhibitor, IMD-0354. The CS-induced reduction in diameter of myotubes and time-dependent degradation of the main contractile protein myosin heavy chain were abolished by NF-κB inhibition. Also, C2 exposure to CS resulted in IκB-α degradation and NF-κB activation, which led to upregulation of the muscle specific E3 ubiquitin ligase MuRF1, but not MAFbx/atrogin-1. In conclusion, our results demonstrate that vapor phase CS exposure to skeletal myotubes triggers NF-κB activation leading to skeletal muscle cell damage and breakdown of muscle proteins mediated by muscle specific E3 ubiquitin ligase MuRF1. Our findings provide another possible molecular mechanism for the catabolic effects of CS in skeletal muscle.

  8. Molecular characterization of LhpR in control of hydroxyproline catabolism and transport in Pseudomonas aeruginosa PAO1.

    Science.gov (United States)

    Li, Guoqing; Lu, Chung-Dar

    2016-07-01

    Utilization of hydroxy-l-proline (l-Hyp) in Pseudomonas aeruginosa requires conversion of l-Hyp to d-Hyp followed by the d-Hyp dehydrogenase pathway; however, the molecular mechanism in control of l-Hyp catabolism and transport was not clear. DNA microarray analysis revealed twelve genes in two adjacent loci that were induced by exogenous l-Hyp and d-Hyp. The first locus includes lhpABFE encoding a Hyp epimerase (LhpA) and d-Hyp dehydrogenase (LhpBEF), while the second locus codes for a putative ABC transporter (LhpPMNO), a protein of unknown function (LhpH), Hyp/Pro racemase (LhpK) and two enzymes in l-Hyp catabolism (LhpC and LhpG). Proximal to these two loci, lhpR encodes a transcriptional regulator of the AraC family. The importance of these genes on l-Hyp catabolism was supported by growth phenotype analysis on knockout mutants. Induction of the lhpA and lhpP promoters by exogenous l-Hyp and d-Hyp was demonstrated by the measurement of β-galactosidase activities from promoter-lacZ fusions in PAO1, and no induction could be detected in the ΔlhpR mutant. Induction of the lhpA promoter by d-Hyp was completely abolished in the lhpA lhpK double mutant devoid of two epimerases, while the induction effect of l-Hyp remained unchanged. The purified His-tagged LhpR binds specifically to the lhp promoter regions, and formation of nucleoprotein complexes is affected by the presence of l-Hyp but not d-Hyp. Putative LhpR binding sites were deduced from serial deletions and comparative genomic sequence analysis. In summary, expression of lhp genes for Hyp catabolism and uptake requires the transcriptional activator LhpR and l-Hyp as the signalling compound.

  9. The putrescine biosynthesis pathway in Lactococcus lactis is transcriptionally regulated by carbon catabolic repression, mediated by CcpA.

    Science.gov (United States)

    Linares, Daniel M; del Río, Beatriz; Ladero, Victor; Redruello, Begoña; Martín, María Cruz; Fernández, María; Alvarez, Miguel A

    2013-07-01

    Lactococcus lactis is the lactic acid bacterium most widely used by the dairy industry as a starter for the manufacture of fermented products such as cheese and buttermilk. However, some strains produce putrescine from agmatine via the agmatine deiminase (AGDI) pathway. The proteins involved in this pathway, including those necessary for agmatine uptake and conversion into putrescine, are encoded by the aguB, aguD, aguA and aguC genes, which together form an operon. This paper reports the mechanism of regulation of putrescine biosynthesis in L. lactis. It is shown that the aguBDAC operon, which contains a cre site at the promoter of aguB (the first gene of the operon), is transcriptionally regulated by carbon catabolic repression (CCR) mediated by the catabolite control protein CcpA.

  10. A product of heme catabolism modulates bacterial function and survival.

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    Christopher L Nobles

    Full Text Available Bilirubin is the terminal metabolite in heme catabolism in mammals. After deposition into bile, bilirubin is released in large quantities into the mammalian gastrointestinal (GI tract. We hypothesized that intestinal bilirubin may modulate the function of enteric bacteria. To test this hypothesis, we investigated the effect of bilirubin on two enteric pathogens; enterohemorrhagic E. coli (EHEC, a Gram-negative that causes life-threatening intestinal infections, and E. faecalis, a Gram-positive human commensal bacterium known to be an opportunistic pathogen with broad-spectrum antibiotic resistance. We demonstrate that bilirubin can protect EHEC from exogenous and host-generated reactive oxygen species (ROS through the absorption of free radicals. In contrast, E. faecalis was highly susceptible to bilirubin, which causes significant membrane disruption and uncoupling of respiratory metabolism in this bacterium. Interestingly, similar results were observed for other Gram-positive bacteria, including B. cereus and S. aureus. A model is proposed whereby bilirubin places distinct selective pressure on enteric bacteria, with Gram-negative bacteria being protected from ROS (positive outcome and Gram-positive bacteria being susceptible to membrane disruption (negative outcome. This work suggests bilirubin has differential but biologically relevant effects on bacteria and justifies additional efforts to determine the role of this neglected waste catabolite in disease processes, including animal models.

  11. Identification of possible cigarette smoke constituents responsible for muscle catabolism.

    Science.gov (United States)

    Rom, Oren; Kaisari, Sharon; Aizenbud, Dror; Reznick, Abraham Z

    2012-08-01

    The age-related loss of muscle mass and strength also known as sarcopenia is significantly influenced by life style factors such as physical inactivity and impaired nutrition. Cigarette smoking is another life style habit that has been shown to be associated with sarcopenia and to affect skeletal muscle. Even today, smoking is still prevalent worldwide and is probably the most significant source of toxic chemicals exposure to humans. Cigarette smoke (CS) is a complex aerosol consisting of thousands of various constituents including reactive oxygen and nitrogen free radicals, toxic aldehydes and more. Previous epidemiological studies have identified tobacco smoking as a risk factor for sarcopenia. Clinical, in vivo and in vitro studies have revealed CS-induced skeletal muscle damage due to impaired muscle metabolism, increased inflammation and oxidative stress, over-expression of atrophy related genes and activation of various intracellular signaling pathways. This review aims to discuss and identify the components of CS that may promote catabolism of skeletal muscle.

  12. Tryptophan and tyrosine catabolic pattern in neuropsychiatric disorders.

    Directory of Open Access Journals (Sweden)

    Ravikumar A

    2000-07-01

    Full Text Available Catabolism of tryptophan and tyrosine in relation to the isoprenoid pathway was studied in neurological and psychiatric disorders. The concentration of trytophan, quinolinic acid, kynurenic acid, serotonin and 5-hydroxyindoleacetic acid was found to be higher in the plasma of patients with all these disorders; while that of tyrosine, dopamine, epinephrine and norepinephrine was lower. There was increase in free fatty acids and decrease in albumin (factors modulating tryptophan transport in the plasma of these patients. Concentration of digoxin, a modulator of amino acid transport, and the activity of HMG CoA reductase, which synthesizes digoxin, were higher in these patients; while RBC membrane Na+-K+ ATPase activity showed a decrease. Concentration of plasma ubiquinone (part of which is synthesised from tyrosine and magnesium was also lower in these patients. No morphine could be detected in the plasma of these patients except in MS. On the other hand, strychnine and nicotine were detectable. These results indicate hypercatabolism of tryptophan and hypocatabolism of tyrosine in these disorders, which could be a consequence of the modulating effect of hypothalamic digoxin on amino acid transport.

  13. Lipid catabolism of invertebrate predator indicates widespread wetland ecosystem degradation

    Science.gov (United States)

    Anteau, Michael J.; Afton, Alan D.

    2011-01-01

    Animals frequently undergo periods when they accumulate lipid reserves for subsequent energetically expensive activities, such as migration or breeding. During such periods, daily lipid-reserve dynamics (DLD) of sentinel species can quantify how landscape modifications affect function, health, and resilience of ecosystems. Aythya affinis (Eyton 1838; lesser scaup; diving duck) are macroinvertebrate predators; they migrate through an agriculturally dominated landscape in spring where they select wetlands with the greatest food density to refuel and accumulate lipid reserves for subsequent reproduction. We index DLD by measuring plasma-lipid metabolites of female scaup (n = 459) that were refueling at 75 spring migration stopover areas distributed across the upper Midwest, USA. We also indexed DLD for females (n = 44) refueling on a riverine site (Pool 19) south of our upper Midwest study area. We found that mean DLD estimates were significantly (Plipid reserves throughout the upper Midwest. Moreover, levels of lipid catabolism are alarming, because scaup use the best quality wetlands available within a given stopover area. Accordingly, these results provide evidence of wetland ecosystem degradation across this large agricultural landscape and document affects that are carried-up through several trophic levels. Interestingly, storing of lipids by scaup at Pool 19 likely reflects similar ecosystem perturbations as observed in the upper Midwest because wetland drainage and agricultural runoff nutrifies the riverine habitat that scaup use at Pool 19. Finally, our results underscore how using this novel technique to monitor DLD, of a carefully selected sentinel species, can index ecosystem health at a landscape scale.

  14. Catabolism of citronellol and related acyclic terpenoids in pseudomonads.

    Science.gov (United States)

    Förster-Fromme, Karin; Jendrossek, Dieter

    2010-07-01

    Terpenes are a huge group of natural compounds characterised by their predominantly pleasant smell. They are built up by isoprene units in cyclic or acyclic form and can be functionalised by carbonyl, hydroxyl or carboxyl groups and by presence of additional carbon-carbon double bonds (terpenoids). Currently, much more than 10,000 terpenoid compounds are known, and many thereof are present in different iso- and stereoforms. Terpenoids are secondary metabolites and can have important biological functions in living organisms. In many cases, the biological functions of terpenoids are not known at all. Nevertheless, terpenoids are used in large quantities as perfumes and aroma compounds for food additives. Terpenoids can be also precursors and building blocks for synthesis of complex chiral compounds in chemical and pharmaceutical industry. Unfortunately, only few terpenoids are available in large quantities at reasonable costs. Therefore, characterisation of suited biocatalysts specific for terpenoid compounds and development of biotransformation processes of abundant terpenoids to commercially interesting derivates becomes more and more important. This minireview summarises knowledge on catabolic pathways and biotransformations of acyclic monoterpenes that have received only little attention. Terpenoids with 20 or more carbon atoms are not a subject of this study.

  15. Catabolism of coffee chlorogenic acids by human colonic microbiota.

    Science.gov (United States)

    Ludwig, Iziar A; Paz de Peña, Maria; Concepción, Cid; Alan, Crozier

    2013-01-01

    Several studies have indicated potential health benefits associated with coffee consumption. These benefits might be ascribed in part to the chlorogenic acids (CGAs), the main (poly)phenols in coffee. The impact of these dietary (poly)phenols on health depends on their bioavailability. As they pass along the gastrointestinal tract, CGAs are metabolized extensively and it is their metabolites rather than the parent compounds that predominate in the circulatory system. This article reports on a study in which after incubation of espresso coffee with human fecal samples, high-performance liquid chromatography-mass spectrometry (HPLC-MS) and gas chromatography-mass spectrometry (GC-MS) were used to monitor CGA breakdown and identify and quantify the catabolites produced by the colonic microflora. The CGAs were rapidly degraded by the colonic microflora and over the 6-h incubation period, 11 catabolites were identified and quantified. The appearance of the initial degradation products, caffeic and ferulic acids, was transient, with maximum quantities at 1 h. Dihydrocaffeic acid, dihydroferulic acid, and 3-(3'-hydroxyphenyl)propionic acid were the major end products, comprising 75-83% of the total catabolites, whereas the remaining 17-25% consisted of six minor catabolites. The rate and extent of the degradation showed a clear influence of the composition of the gut microbiota of individual volunteers. Pathways involved in colonic catabolism of CGAs are proposed and comparison with studies on the bioavailability of coffee CGAs ingested by humans helped distinguish between colonic catabolites and phase II metabolites of CGAs.

  16. Allantoin catabolism influences the production of antibiotics in Streptomyces coelicolor.

    Science.gov (United States)

    Navone, Laura; Casati, Paula; Licona-Cassani, Cuauhtémoc; Marcellin, Esteban; Nielsen, Lars K; Rodriguez, Eduardo; Gramajo, Hugo

    2014-01-01

    Purines are a primary source of carbon and nitrogen in soil; however, their metabolism is poorly understood in Streptomyces. Using a combination of proteomics, metabolomics, and metabolic engineering, we characterized the allantoin pathway in Streptomyces coelicolor. When cells grew in glucose minimal medium with allantoin as the sole nitrogen source, quantitative proteomics identified 38 enzymes upregulated and 28 downregulated. This allowed identifying six new