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Sample records for 6p isoforms inhibit

  1. Isoform-specific Inhibition of Cyclophilins

    PubMed Central

    Daum, Sebastian; Schumann, Michael; Mathea, Sebastian; Aumüller, Tobias; Balsley, Molly A.; Constant, Stephanie L.; de Lacroix, Boris Féaux; Kruska, Fabian; Braun, Manfred; Schiene-Fischer, Cordelia

    2009-01-01

    Cyclophilins belong to the enzyme class of peptidyl prolyl cis/trans isomerases which catalyze the cis/trans isomerization of prolyl bonds in peptides and proteins in different folding states. Cyclophilins have been shown to be involved in a multitude of cellular functions like cell growth, proliferation, and motility. Among the 20 human cyclophilin isoenzymes, the two most abundant members of the cyclophilin family CypA and CypB exhibit specific cellular functions in several inflammatory diseases, cancer development and HCV replication. A small-molecule inhibitor on the basis of aryl 1-indanylketones has now been shown to discriminate between CypA and CypB in vitro. CypA binding of this inhibitor has been characterized by fluorescence anisotropy- and isothermal titration calorimetry-based cyclosporin competition assays. Inhibition of CypA- but not CypB-mediated chemotaxis of mouse CD4+ T cells by the inhibitor provided biological proof of discrimination in vivo. PMID:19480458

  2. Activation and inhibition of adenylyl cyclase isoforms by forskolin analogs.

    PubMed

    Pinto, Cibele; Papa, Dan; Hübner, Melanie; Mou, Tung-Chung; Lushington, Gerald H; Seifert, Roland

    2008-04-01

    Adenylyl cyclase (AC) isoforms 1 to 9 are differentially expressed in tissues and constitute an interesting drug target. ACs 1 to 8 are activated by the diterpene, forskolin (FS). It is unfortunate that there is a paucity of AC isoform-selective activators. To develop such compounds, an understanding of the structure/activity relationships of diterpenes is necessary. Therefore, we examined the effects of FS and nine FS analogs on ACs 1, 2, and 5 expressed in Spodoptera frugiperda insect cells. Diterpenes showed the highest potencies at AC1 and the lowest potencies at AC2. We identified full agonists, partial agonists, antagonists, and inverse agonists, i.e., diterpenes that reduced basal AC activity. Each AC isoform exhibited a distinct pharmacological profile. AC2 showed the highest basal activity of all AC isoforms and highest sensitivity to inverse agonistic effects of 1-deoxy-forskolin, 7-deacetyl-1,9-dideoxy-forskolin, and, particularly, BODIPY-forskolin. In contrast, BODIPY-forskolin acted as partial agonist at the other ACs. 1-Deoxy-forskolin analogs were devoid of agonistic activity at ACs but antagonized the effects of FS in a mixed competitive/noncompetitive manner. At purified catalytic AC subunits, BODIPY-forskolin acted as weak partial agonist/strong partial antagonist. Molecular modeling revealed that the BODIPY group rotates promiscuously outside of the FS-binding site. Collectively, ACs are not uniformly activated and inhibited by FS and FS analogs, demonstrating the feasibility to design isoform-selective FS analogs. The two- and multiple-state models, originally developed to conceptualize ligand effects at G-protein-coupled receptors, can be applied to ACs to explain certain experimental data.

  3. By activating Fas/ceramide synthase 6/p38 kinase in lipid rafts, stichoposide D inhibits growth of leukemia xenografts.

    PubMed

    Yun, Seong-Hoon; Park, Eun-Seon; Shin, Sung-Won; Ju, Mi-Ha; Han, Jin-Yeong; Jeong, Jin-Sook; Kim, Sung-Hyun; Stonik, Valentin A; Kwak, Jong-Young; Park, Joo-In

    2015-09-29

    Stichoposide D (STD) is a marine triterpene glycoside isolated from sea cucumbers. We examined the molecular mechanisms underlying the antitumor activity of STD in human leukemia cells. The role of Fas (CD95), ceramide synthase 6 (CerS6) and p38 kinase during STD-induced apoptosis was examined in human leukemia cells. In addition, the antitumor effects of STD in K562 and HL-60 leukemia xenograft models were investigated. We found that STD induces Fas translocation to lipid rafts, and thus mediates cell apoptosis. We also observed the activation of CerS6 and p38 kinase during STD-induced apoptosis. The use of methyl-β-cyclodextrin and nystatin to disrupt lipid rafts prevents the clustering of Fas and the activation of CerS6 and p38 kinase, and also inhibits STD-induced apoptosis. Specific inhibition by Fas, CerS6, and p38 kinase siRNA transfection partially blocked STD-induced apoptosis. In addition, STD has antitumor activity through the activation of CerS6 and p38 kinase without displaying any toxicity in HL-60 and K562 xenograft models. We observed that the anti-tumor effect of STD is partially prevented in CerS6 shRNA-silenced xenograft models. We first report that Fas/CerS6/p38 kinase activation in lipid rafts by STD is involved in its anti-leukemic activity. We also established that STD is able to enhance the chemosensitivity of K562 cells to etoposide or Ara-C. These data suggest that STD may be used alone or in combination with other chemotherapeutic agents to treat leukemia.

  4. By activating Fas/ceramide synthase 6/p38 kinase in lipid rafts, Stichoposide D inhibits growth of leukemia xenografts

    PubMed Central

    Yun, Seong-Hoon; Park, Eun-Seon; Shin, Sung-Won; Ju, Mi-Ha; Han, Jin-Yeong; Jeong, Jin-Sook; Kim, Sung-Hyun; Stonik, Valentin A.; Kwak, Jong-Young; Park, Joo-In

    2015-01-01

    Stichoposide D (STD) is a marine triterpene glycoside isolated from sea cucumbers. We examined the molecular mechanisms underlying the antitumor activity of STD in human leukemia cells. The role of Fas (CD95), ceramide synthase 6 (CerS6) and p38 kinase during STD-induced apoptosis was examined in human leukemia cells. In addition, the antitumor effects of STD in K562 and HL-60 leukemia xenograft models were investigated. We found that STD induces Fas translocation to lipid rafts, and thus mediates cell apoptosis. We also observed the activation of CerS6 and p38 kinase during STD-induced apoptosis. The use of methyl-β-cyclodextrin and nystatin to disrupt lipid rafts prevents the clustering of Fas and the activation of CerS6 and p38 kinase, and also inhibits STD-induced apoptosis. Specific inhibition by Fas, CerS6, and p38 kinase siRNA transfection partially blocked STD-induced apoptosis. In addition, STD has antitumor activity through the activation of CerS6 and p38 kinase without displaying any toxicity in HL-60 and K562 xenograft models. We observed that the anti-tumor effect of STD is partially prevented in CerS6 shRNA-silenced xenograft models. We first report that Fas/CerS6/p38 kinase activation in lipid rafts by STD is involved in its anti-leukemic activity. We also established that STD is able to enhance the chemosensitivity of K562 cells to etoposide or Ara-C. These data suggest that STD may be used alone or in combination with other chemotherapeutic agents to treat leukemia. PMID:26318294

  5. Nitric oxide synthases activation and inhibition by metallacarborane-cluster-based isoform-specific affectors.

    PubMed

    Kaplánek, Robert; Martásek, Pavel; Grüner, Bohumír; Panda, Satya; Rak, Jakub; Masters, Bettie Sue Siler; Král, Vladimír; Roman, Linda J

    2012-11-26

    A small library of boron-cluster- and metallacarborane-cluster-based ligands was designed, prepared, and tested for isoform-selective activation or inhibition of the three nitric oxide synthase isoforms. On the basis of the concept of creating a hydrophobic analogue of a natural substrate, a stable and nontoxic basic boron cluster system, previously used for boron neutron capture therapy, was modified by the addition of positively charged moieties to its periphery, providing hydrophobic and nonclassical hydrogen bonding interactions with the protein. Several of these compounds show efficacy for inhibition of NO synthesis with differential effects on the various nitric oxide synthase isoforms.

  6. VEGF111b, a new member of VEGFxxxb isoforms and induced by mitomycin C, inhibits angiogenesis

    SciTech Connect

    Gu, Fang; Li, Xiuli; Kong, Jian; Pan, Bing; Sun, Min; Zheng, Lemin; Yao, Yuanqing

    2013-11-08

    Highlights: •We discovered a new member of VEGFxxxb family-VEGF111b. •We found VEGF111b mRNA and protein can be induced by mitomycin C. •We confirmed VEGF111b over-expression inhibits angiogenesis. •VEGF111b inhibits angiogenesis through inhibiting VEGF-R2/PI3K/Akt and VEGF-R2/ERK1/2 phosphorylation. -- Abstract: Vascular endothelial growth factor (VEGF-A) stimulating angiogenesis is required for tumor growth and progression. The conventional VEGF-A isoforms have been considered as pro-angiogenic factors. Another family of VEGF-A isoforms generated by alternative splicing, termed VEGFxxxb isoforms, has anti-angiogenic property, exemplified by VEGF165b. Here, we identify a new number of VEGFxxx family-VEGF111b induced by mitomycin C, although not detected in mitomycin C-unexposed ovarian cancer cells. SKOV3 cells were transfected with pcDNA{sub 3.1} empty vector, pcDNA{sub 3.1}-VEGF111b or pcDNA{sub 3.1}-VEGF165b to collect conditioned mediums respectively. VEGF111b overexpression inhibits proliferation, migration and tube formation of endothelial cell by inhibiting VEGF-R2 phosphorylation and its downstream signaling, similar to VEGF165b but slightly lower than VEGF165b. The anti-angiogenic property depends on the six amino acids of exon 8b of the VEGFxxxb isoforms. Our results show that VEGF111b is a novel potent anti-angiogenic agent that can target the VEGF-R2 and its signaling pathway to inhibit ovarian tumor growth.

  7. Biotransformation of baicalin to baicalein significantly strengthens the inhibition potential towards UDP-glucuronosyltransferases (UGTs) isoforms.

    PubMed

    Teng, Yanjie; Nian, Hong; Zhao, Hongtao; Chen, Pei; Wang, Guan

    2013-09-01

    The aim of the present study was to investigate the influence of biotransformation of baicalin into baicalein towards the inhibition potential towards one of the most important drug-metabolizing enzymes (DMEs) UDP-glucuronosyltransferases (UGTs). in vitro incubation method using recombinant UGTs-catalyzed 4-methylumbelliferone (4-MU) glucuronidation was used to evaluate the inhibition towards important UGT isoforms in the liver, including UGT1A1, 1A3, 1A6, 1A9, and 2B7. At the same concentration (100 microM), baicalein showed stronger inhibition potential than baicalin towards all the tested UGT isoforms. Data fitting using Dixon plot and Lineweaver-Burk plot was carried out to determine the inhibition type, and the second plot with the slopes from Lineweaver-Burk plot towards baicalein's concentrations was used to calculate the inhibition kinetic parameters (K(i)). Competitive inhibition type was observed for UGT1A1, 1A6, 1A9 and 2B7, and noncompetitive inhibition was detected for UGT1A3. The inhibition kinetic parameters (K(i)) were calculated to be 1.2, 5.1, 15.3, 26.3, and 48.9 microM for UGT1A1, 1A3, 1A6, 1A9, and 2B7, respectively. All these information reminds us of the necessary monitoring when oral administration of baicalin or baicalin-containing herbs.

  8. Inhibition of adenylyl and guanylyl cyclase isoforms by the antiviral drug foscarnet.

    PubMed

    Kudlacek, O; Mitterauer, T; Nanoff, C; Hohenegger, M; Tang, W J; Freissmuth, M; Kleuss, C

    2001-02-02

    The pyrophosphate (PP(i)) analog foscarnet inhibits viral DNA-polymerases and is used to treat cytomegalovirus and human immunodeficiency vius infections. Nucleotide cyclases and DNA-polymerases catalyze analogous reactions, i.e. a phosphodiester bond formation, and have similar topologies in their active sites. Inhibition by foscarnet of adenylyl cyclase isoforms was therefore tested with (i) purified catalytic domains C1 and C2 of types I and VII (IC1 and VIIC1) and of type II (IIC2) and (ii) membrane-bound holoenzymes (from mammalian tissues and types I, II, and V heterologously expressed in Sf9 cell membranes). Foscarnet was more potent than PP(i) in suppressing forskolin-stimulated catalysis by both, IC1/IIC2 and VIIC1/IIC2. Stimulation of VIIC1/IIC2 by Galpha(s) relieved the inhibition by foscarnet but not that by PP(i). The IC(50) of foscarnet on membrane-bound adenylyl cyclases also depended on their mode of regulation. These findings predict that receptor-dependent cAMP formation is sensitive to inhibition by foscarnet in some, but not all, cells. This was verified with two cell lines; foscarnet blocked cAMP accumulation after A(2A)-adenosine receptor stimulation in PC12 but not in HEK-A(2A) cells. Foscarnet also inhibited soluble and, to a lesser extent, particulate guanylyl cylase. Thus, foscarnet interferes with the generation of cyclic nucleotides, an effect which may give rise to clinical side effects. The extent of inhibition varies with the enzyme isoform and with the regulatory input.

  9. Chiral Inhibition of Rivaroxaban Derivatives Towards UDP-Glucuronosyltransferase (UGT) Isoforms.

    PubMed

    Yao, Zhuhua; Liu, Yong-Zhe; Ma, Ai-Lun; Wang, Shu-Fen; Lu, Dan; Hu, Cui-Min; Zhang, Yan-Yan; Wang, Haina; Hu, Lingyun; Deng, Jun; Yang, Kun; Fang, Zhong-Ze

    2015-12-01

    Rivaroxaban is an oral direct factor Xa (FXa) inhibitor clinically used to prevent and treat thromboembolic disorders. Drug-drug interaction (DDI) exist for rivaroxaban and the inhibitors of CYP3A4/5. This study aims to investigate the inhibition of rivaroxaban and its derivatives with a chiral center towards UDP-glucuronosyltransferases (UGTs). Chemical synthesis was performed to obtain rivaroxaban derivatives with different chiral centers. UGTs supersomes-catalyzed 4-methylumbelliferone (4-MU) glucuronidation was employed to evaluate the inhibition potential towards various UGT isoforms. A significant influence of rivaroxaban derivatives towards UGT1A3 was observed. Chiral centers produce different effects towards the effect of four pairs of rivaroxaban derivatives towards UGT1A3 activity, with stronger inhibition potential of S1 than R1, but stronger inhibition capability of R2, R3, R4 than S2, S3, and S4. Competitive inhibition of R3 and R4 towards UGT1A3 was demonstrated by Dixon and Lineweaver-Burk plots. In conclusion, the significant influence of rivaroxaban derivatives towards UGT1A3's activity was demonstrated in the present study. The chirality centers highly affected the inhibition behavior of rivaroxaban derivatives towards UGT1A3.

  10. Inhibition of carbonic anhydrase isoforms I, II, IX and XII with novel Schiff bases: identification of selective inhibitors for the tumor-associated isoforms over the cytosolic ones.

    PubMed

    Sarikaya, Busra; Ceruso, Mariangela; Carta, Fabrizio; Supuran, Claudiu T

    2014-11-01

    A series of new Schiff bases was obtained from sulfanilamide, 3-fluorosulfanilamide or 4-(2-aminoethyl)-benzenesulfonamide and aromatic/heterocyclic aldehydes incorporating both hydrophobic and hydrophilic moieties. The obtained sulfonamides were investigated as inhibitors of four physiologically relevant carbonic anhydrase (CA, EC 4.2.1.1) isoforms, the cytosolic CA I and II, as well as the transmembrane, tumor-associated CA IX and XII. Most derivatives were medium potency or weak hCA I/II inhibitors, but several of them showed nanomolar affinity for CA IX and/or XII, making them an interesting example of isoform-selective compounds. The nature of the aryl/hetaryl moiety present in the initial aldehyde was the main factor influencing potency and isoform selectivity. The best and most CA IX-selective compounds incorporated moieties such as 4-methylthiophenyl, 4-cyanophenyl-, 4-(2-pyridyl)-phenyl and the 4-aminoethylbenzenesulfonamide scaffold. The best hCA XII inhibitors, also showing selectivity for this isoform, incorporated 2-methoxy-4-nitrophenyl-, 2,3,5,6-tetrafluorophenyl and 4-(2-pyridyl)-phenyl functionalities and were also derivatives of 4-aminoethylbenzenesulfonamide. The sulfanilamide and 3-fluorosulfanilamide derived Schiff bases were less active compared to the corresponding 4-aminoethyl-benzenesulfonamide derivatives. As hCA IX/XII selective inhibition is attractive for obtaining antitumor agents/diagnostic tools with a new mechanism of action, compounds of the type described here may be considered interesting preclinical candidates.

  11. Inhibition of carbonic anhydrase isoforms I, II, IX and XII with secondary sulfonamides incorporating benzothiazole scaffolds.

    PubMed

    Petrou, Anthi; Geronikaki, Athina; Terzi, Emine; Guler, Ozen Ozensoy; Tuccinardi, Tiziano; Supuran, Claudiu T

    2016-12-01

    Carbonic anhydrases (CAs, EC 4.2.1.1) catalyze the fundamental reaction of CO2 hydration in all living organisms, being actively involved in the regulation of a plethora of patho/physiological conditions. A series of benzothiazole-based sulfonamides were synthesized and tested as possible CA inhibitors. Their inhibitory activity was assessed against the cytosolic human isoforms hCA I and hCA II and the transmembrane hCA IX and hCA XII. Several of the investigated derivatives showed interesting inhibition activity and selectivities for inhibiting hCA IX and hCA XII over the off-target ones hCA I and hCA II. Furthermore, computational procedures were used to investigate the binding mode of this class of compounds, within the active site of hCA IX.

  12. A Unified Proteochemometric Model for Prediction of Inhibition of Cytochrome P450 Isoforms

    PubMed Central

    Lapins, Maris; Worachartcheewan, Apilak; Spjuth, Ola; Georgiev, Valentin; Prachayasittikul, Virapong; Nantasenamat, Chanin; Wikberg, Jarl E. S.

    2013-01-01

    A unified proteochemometric (PCM) model for the prediction of the ability of drug-like chemicals to inhibit five major drug metabolizing CYP isoforms (i.e. CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A4) was created and made publicly available under the Bioclipse Decision Support open source system at www.cyp450model.org. In regards to the proteochemometric modeling we represented the chemical compounds by molecular signature descriptors and the CYP-isoforms by alignment-independent description of composition and transition of amino acid properties of their protein primary sequences. The entire training dataset contained 63 391 interactions and the best PCM model was obtained using signature descriptors of height 1, 2 and 3 and inducing the model with a support vector machine. The model showed excellent predictive ability with internal AUC = 0.923 and an external AUC = 0.940, as evaluated on a large external dataset. The advantage of PCM models is their extensibility making it possible to extend our model for new CYP isoforms and polymorphic CYP forms. A key benefit of PCM is that all proteins are confined in one single model, which makes it generally more stable and predictive as compared with single target models. The inclusion of the model in Bioclipse Decision Support makes it possible to make virtual instantaneous predictions (∼100 ms per prediction) while interactively drawing or modifying chemical structures in the Bioclipse chemical structure editor. PMID:23799117

  13. Selective inhibition of the cytochrome P450 isoform by hyperoside and its potent inhibition of CYP2D6.

    PubMed

    Song, Min; Hong, Miri; Lee, Min Young; Jee, Jun-Goo; Lee, You Mie; Bae, Jong-Sup; Jeong, Tae Cheon; Lee, Sangkyu

    2013-09-01

    Hyperoside, quercetin-3-O-galactoside, is a flavonoid isolated from Oenanthe javanica. In the present study, we investigated potential herb-drug inhibitory effects of hyperoside on nine cytochrome P450 (CYP) isoforms in pooled human liver microsomes (HLMs) and human recombinant cDNA expressed CYP using a cocktail probe assay. Hyperoside strongly inhibited CYP2D6-catalyzed dextromethorphan O-demethylation, with IC₅₀ values of 1.2 and 0.81 μM after 0 and 15 min of preincubation, and a Ki value of 2.01 μM in HLMs, respectively. Hyperoside strongly decreased CYP2D6 activity dose-, but not time-, dependently in HLMs. In addition, the Lineweaver-Burk and Secondary plots for the inhibition of CYP2D6 in HLMs fitted a competitive inhibition mode. Furthermore, hyperoside decreased CYP2D6-catalyzed dextromethorphan O-demethylation activity of human recombinant cDNA-expressed CYP2D6, with an IC₅₀ value of 3.87 μM. However, other CYPs were not inhibited significantly by hyperoside. In conclusion, our data demonstrate that hyperoside is a potent selective CYP2D6 inhibitor in HLMs, and suggest that hyperoside might cause herb-drug interactions when co-administrated with CYP2D substrates.

  14. LRP-mediated clearance of Abeta is inhibited by KPI-containing isoforms of APP.

    PubMed

    Moir, Robert D; Tanzi, Rudolph E

    2005-04-01

    The pathogenesis of Alzheimer's disease (AD) involves the abnormal accumulation and deposition of beta-amyloid in cerebral blood vessels and in the brain parenchyma. Critical in modulating beta-amyloid deposition in brain is the flux of Abeta across the blood brain barrier. The low-density lipoprotein receptor-related protein (LRP), is a large endocytic receptor that mediates the efflux of Abeta out of brain and into the periphery. The first step in the LRP-mediated clearance of Abeta involves the formation of a complex between Abeta and the LRP ligands apolipoprotein E (apoE) or alpha(2)-macroglobulin (alpha(2)M). The Abeta/chaperone complexes then bind to LRP via binding sites on apoE or alpha(2)M. The efflux of Abeta/chaperone complexes out of the neuropil and into the periphery may be attenuated by LRP-ligands that compete with apoE or alpha(2)M for LRP binding. LRP is also the cell surface receptor for Kunitz Protease Inhibitor (KPI) containing isoforms of Abeta's parent protein, the amyloid protein precursor (APP). Protein and mRNA levels of KPI-containing APP isoforms (APP-KPI) are elevated in AD brain and are associated with increased Abeta production. In this study we show that soluble non-amyloidogenic APP-KPI can also inhibit the uptake of Abeta/alpha(2)M in a cell culture model of LRP mediated Abeta clearance. Clearance of Abeta/apoE complexes was not inhibited by APP-KPI. Our findings are consistent with studies showing that apoE and alpha(2)M have discrete binding sites on LRP. Most significantly, our data suggests that the elevated levels of APP-KPI in AD brain may attenuate the clearance of Abeta, the proteins own amyloidogenic catabolic product.

  15. Discovery of macrocyclic peptides armed with a mechanism-based warhead: isoform-selective inhibition of human deacetylase SIRT2.

    PubMed

    Morimoto, Jumpei; Hayashi, Yuuki; Suga, Hiroaki

    2012-04-02

    Designed to inhibit: by using the random nonstandard peptide integrated discovery (RaPID) system, highly potent isoform-selective inhibitors can be identified from a library of nonstandard macrocyclic peptides. These inhibitors, which contain a mechanism-based warhead residue, are active against the human deacetylase SIRT2, with IC(50) values in the low nanomolar region.

  16. Mechanism of inhibition of protein kinase C by 14-3-3 isoforms. 14-3-3 isoforms do not have phospholipase A2 activity.

    PubMed Central

    Robinson, K; Jones, D; Patel, Y; Martin, H; Madrazo, J; Martin, S; Howell, S; Elmore, M; Finnen, M J; Aitken, A

    1994-01-01

    The ability of individual members of the 14-3-3 protein family to inhibit protein kinase C (PKC) has been studied by using a synthetic peptide based on the specific 80 kDa substrate for PKC (MARCKS protein) in two different assay systems. Recombinant 14-3-3 and isoforms renatured by a novel method after separation by reverse-phase h.p.l.c. were studied. The detailed effects of diacylglycerol and the phorbol ester phorbol 12-myristate 13-acetate on the inhibition were also investigated. This suggests that one of the sites of interaction of 14-3-3 may be the cysteine-rich (C1) domain in PKC. Since a region in secreted phospholipase A2 (PLA2) shares similarity with this domain, the ability of 14-3-3 to interact with mammalian PLA2 was studied. Cytosolic PLA2 has some similarity to the C2 region of PKC, and the effect of 14-3-3 on this class of PLA2 was also analysed. In contrast with a previous report, no PLA2 activity was found in brain 14-3-3, nor in any of the recombinant proteins tested. These include zeta 14-3-3 isoform, on which the original observation was made. Images Figure 2 PMID:8192676

  17. Isatin-pyrazole benzenesulfonamide hybrids potently inhibit tumor-associated carbonic anhydrase isoforms IX and XII.

    PubMed

    Ibrahim, Hany S; Abou-Seri, Sahar M; Tanc, Muhammet; Elaasser, Mahmoud M; Abdel-Aziz, Hatem A; Supuran, Claudiu T

    2015-10-20

    New series of benzenesulfonamide derivatives incorporating pyrazole and isatin moieties were prepared using celecoxib as lead molecule. Biological evaluation of the target compounds was performed against the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1) and more precisely against the human isoforms hCA I, II (cytosolic), IX and XII (transmembrane, tumor-associated enzymes). Most of the tested compounds efficiently inhibited hCA I, II and IX, with KIs of 2.5-102 nM, being more effective than the reference drug acetazolamide. Compounds 11e, 11f, 16e and 16f were found to inhibit hCA XII with Ki of 3.7, 6.5, 5.4 and 7.2 nM, respectively. Compounds 11e and 16e, with 5-NO2 substitution on the isatin ring, were found to be selective inhibitors of hCA IX and hCA XII. Docking studies revealed that the NO2 group of both compounds participate in interactions with Asp132 within the hCA IX active site, and with residues Lys67 and Asp130 in hCA XII, respectively.

  18. Substrate specificity, kinetic properties and inhibition by fumonisin B1 of ceramide synthase isoforms from Arabidopsis.

    PubMed

    Luttgeharm, Kyle D; Cahoon, Edgar B; Markham, Jonathan E

    2016-03-01

    Ceramide makes up the acyl-backbone of sphingolipids and plays a central role in determining the function of these essential membrane lipids. In Arabidopsis, the varied chemical composition of ceramide is determined by the specificity of three different isoforms of ceramide synthase, denoted LAG one homologue 1, -2 and -3 (LOH1, LOH2 and LOH3), for a range of long-chain base (LCB) and acyl-CoA substrates. The contribution of each of these isoforms to the synthesis of ceramide was investigated by in vitro ceramide synthase assays. The plant LCB phytosphingosine was efficiently used by the LOH1 and LOH3 isoforms, with LOH1 having the lowest Km for the LCB substrate of the three isoforms. In contrast, sphinganine was used efficiently only by the LOH2 isoform. Acyl-CoA specificity was also distinguished between the three isoforms with LOH2 almost completely specific for palmitoyl-CoA whereas the LOH1 isoform showed greatest activity with lignoceroyl- and hexacosanoyl-CoAs. Interestingly, unsaturated acyl-CoAs were not used efficiently by any isoform whereas unsaturated LCB substrates were preferred by LOH2 and 3. Fumonisin B1 (FB1) is a general inhibitor of ceramide synthases but LOH1 was found to have a much lower Ki than the other isoforms pointing towards the origin of FB1 sensitivity in plants. Overall, the data suggest distinct roles and modes of regulation for each of the ceramide synthases in Arabidopsis sphingolipid metabolism.

  19. The affinities of human platelet and Acanthamoeba profilin isoforms for polyphosphoinositides account for their relative abilities to inhibit phospholipase C.

    PubMed Central

    Machesky, L M; Goldschmidt-Clermont, P J; Pollard, T D

    1990-01-01

    In light of recent work implicating profilin from human platelets as a possible regulator of both cytoskeletal dynamics and inositol phospholipid-mediated signaling, we have further characterized the interaction of platelet profilin and the two isoforms of Acanthamoeba profilin with inositol phospholipids. Profilin from human platelets binds to phosphatidylinositol-4-monophosphate (PIP) and phosphatidylinositol-4,5-bisphosphate (PIP2) with relatively high affinity (Kd approximately 1 microM for PIP2 by equilibrium gel filtration), but interacts only weakly (if at all) with phosphatidylinositol (PI) or inositol trisphosphate IP3) in small-zone gel-filtration assays. The two isoforms of Acanthamoeba profilin both have a lower affinity for PIP2 than does human platelet profilin, but the more basic profilin isoform from Acanthamoeba (profilin-II) has a much higher (approximately 10-microM Kd) affinity than the acidic isoform (profilin-I, 100 to 500-microM Kd). None of the profilins bind to phosphatidylserine (PS) or phosphatidylcholine (PC) in small-zone gel-filtration experiments. The differences in affinity for PIP2 parallel the ability of these three profilins to inhibit PIP2 hydrolysis by soluble phospholipase C (PLC). The results show that the interaction of profilins with PIP2 is specific with respect to both the lipid and the proteins. In Acanthamoeba, the two isoforms of profilin may have specialized functions on the basis of their identical (approximately 10 microM) affinities for actin monomers and different affinities for PIP2. PMID:1966040

  20. Upregulation of functional Kv11.1 isoform expression by inhibition of intronic polyadenylation with antisense morpholino oligonucleotides.

    PubMed

    Gong, Qiuming; Stump, Matthew R; Zhou, Zhengfeng

    2014-11-01

    The KCNH2 gene encodes the Kv11.1 potassium channel that conducts the rapidly activating delayed rectifier current in the heart. KCNH2 pre-mRNA undergoes alternative processing; intron 9 splicing leads to the formation of a functional, full-length Kv11.1a isoform, while polyadenylation within intron 9 generates a non-functional, C-terminally truncated Kv11.1a-USO isoform. The relative expression of Kv11.1 isoforms plays an important role in the regulation of Kv11.1 channel function and the pathogenesis of long QT syndrome. In this study, we identified cis-acting elements that are required for KCNH2 intron 9 poly(A) signal activity. Mutation of these elements decreased Kv11.1a-USO expression and increased the expression of Kv11.1a mRNA, protein and channel current. More importantly, blocking these elements by antisense morpholino oligonucleotides shifted the alternative processing of KCNH2 intron 9 from the polyadenylation to the splicing pathway, leading to the predominant production of Kv11.1a and a significant increase in Kv11.1 current. Our findings indicate that the expression of the Kv11.1a isoform can be upregulated by an antisense approach. Antisense inhibition of KCNH2 intronic polyadenylation represents a novel approach to increase Kv11.1 channel function.

  1. Inhibition of Na+/H+ Exchanger Isoform 1 Is Neuroprotective in Neonatal Hypoxic Ischemic Brain Injury

    PubMed Central

    Kleman, Neil; Uluc, Kutluay; Kendigelen, Pinar; Hagemann, Tracy; Akture, Erinc; Messing, Albee; Ferrazzano, Peter; Sun, Dandan

    2011-01-01

    Abstract We investigated the role of Na+/H+ exchanger isoform 1 (NHE-1) in neonatal hypoxia/ischemia (HI). HI was induced by unilateral ligation of the left common carotid artery in postnatal day 9 (P9) mice, and subsequent exposure of animals to 8% O2 for 55 min. A pre/posttreatment group received a selective and potent NHE-1 inhibitor HOE 642 (0.5 mg/kg, intraperitoneally) 5 min before HI, then at 24 and 48 h after HI. A posttreatment group received HOE 642 (0.5 mg/kg) at 10 min, 24 h, and 48 h after HI. Saline injections were used as vehicle controls. The vehicle-control brains at 72 h after HI exhibited neuronal degeneration in the ipsilateral hippocampus, striatum, and thalamus, as identified with Fluoro-Jade C positive staining and loss of microtubule-associated protein 2 (MAP2) expression. NHE-1 protein was upregulated in glial fibrillary acidic protein–positive reactive astrocytes. In HOE 642–treated brains, the morphologic hippocampal structures were better preserved and displayed less neurodegeneration and a higher level of MAP2 expression. Motor-learning deficit was detected at 4 weeks of age after HI in the vehicle control group. Inhibition of NHE-1 in P9 mice not only reduced neurodegeneration during the acute stage of HI but also improved the striatum-dependent motor learning and spatial learning at 8 weeks of age after HI. These findings suggest that NHE-1–mediated disruption of ionic homeostasis contributes to striatal and CA1 pyramidal neuronal injury after neonatal HI. Antioxid. Redox Signal. 14, 1803–1813. PMID:20712402

  2. Structural Basis for Isoform-Selective Inhibition in Nitric Oxide Synthase

    PubMed Central

    LI, HUIYING

    2013-01-01

    CONSPECTUS Nitric oxide synthase (NOS) converts L-arginine into L-citrulline and releases the important signaling molecule nitric oxide (NO). In the cardiovascular system NO produced by endothelial NOS (eNOS) relaxes smooth muscle which controls vascular tone and blood pressure.Neuronal NOS (nNOS) produces NO in the brain, where it influences a variety of neural functions such as neural transmitter release. NO can also support immune system, serving as a cytotoxic agent during infections. Even with all of these important functions, NO is a free radical, and, when overproduced, it can cause tissue damage. This mechanism can operate in many neurodegenerative diseases, and as a result, the development of drugs targeting nNOS is a desirable therapeutic goal. However, the active sites of all 3 human isoforms are very similar, and designing inhibitors specific for nNOS is a challenging problem. It is critically important, for example, not to inhibit eNOS owing to its central role in controlling blood pressure. In this Account we summarize our efforts in collaboration with Rick Silverman at Northwestern University to develop drug candidates that specifically target NOS using crystallography, computational chemistry, and organic synthesis. As a result we have developed aminopyridine compounds that are 3,800 fold more selective for nNOS than eNOS, some of which show excellent neuro-protective effects in animal models. Our group has solved approximately 130 NOS-inhibitor crystal structures which have provided the structural basis for our design efforts. Initial crystal structures of nNOS and eNOS bound to selective dipeptide inhibitors showed that a single amino acid difference (Asp in nNOS and Asn in eNOS) results in much tighter binding to nNOS. The NOS active site is open and rigid, which produces few large structural changes when inhibitors bind. However, we have found that relatively small changes in the active site and inhibitor chirality can account for large

  3. Dendrimers incorporating benzenesulfonamide moieties strongly inhibit carbonic anhydrase isoforms I-XIV.

    PubMed

    Carta, Fabrizio; Osman, Sameh M; Vullo, Daniela; AlOthman, Zeid; Supuran, Claudiu T

    2015-06-21

    As extension of our previous study herein we report a comprehensive investigation of poly(amidoamine) (PAMAM) dendrimers as modulators of the human carbonic anhydrase (hCA, EC 4.2.1.1) isoforms I-XIV. Interestingly inhibitory activity was observed for the non-functionalized dendrimers against the hCA I, VII, IX, XII and XIV isoforms, whereas activation properties were reported only for the cytosolic abundant hCA II. Highly efficient inhibitory action against many isoforms having medicinal chemistry applications, such as hCA II, V, VII, IX, XII and XIV, was observed for the PAMAM functionalized counterparts bearing 4, 8, 16 and 32 benzenesulfonamide moieties. Possible applications of dendrimer-CA inhibitors as therapeutic/diagnostic agents are envisaged.

  4. Structural basis of Nav1.7 inhibition by an isoform-selective small-molecule antagonist.

    PubMed

    Ahuja, Shivani; Mukund, Susmith; Deng, Lunbin; Khakh, Kuldip; Chang, Elaine; Ho, Hoangdung; Shriver, Stephanie; Young, Clint; Lin, Sophia; Johnson, J P; Wu, Ping; Li, Jun; Coons, Mary; Tam, Christine; Brillantes, Bobby; Sampang, Honorio; Mortara, Kyle; Bowman, Krista K; Clark, Kevin R; Estevez, Alberto; Xie, Zhiwei; Verschoof, Henry; Grimwood, Michael; Dehnhardt, Christoph; Andrez, Jean-Christophe; Focken, Thilo; Sutherlin, Daniel P; Safina, Brian S; Starovasnik, Melissa A; Ortwine, Daniel F; Franke, Yvonne; Cohen, Charles J; Hackos, David H; Koth, Christopher M; Payandeh, Jian

    2015-12-18

    Voltage-gated sodium (Nav) channels propagate action potentials in excitable cells. Accordingly, Nav channels are therapeutic targets for many cardiovascular and neurological disorders. Selective inhibitors have been challenging to design because the nine mammalian Nav channel isoforms share high sequence identity and remain recalcitrant to high-resolution structural studies. Targeting the human Nav1.7 channel involved in pain perception, we present a protein-engineering strategy that has allowed us to determine crystal structures of a novel receptor site in complex with isoform-selective antagonists. GX-936 and related inhibitors bind to the activated state of voltage-sensor domain IV (VSD4), where their anionic aryl sulfonamide warhead engages the fourth arginine gating charge on the S4 helix. By opposing VSD4 deactivation, these compounds inhibit Nav1.7 through a voltage-sensor trapping mechanism, likely by stabilizing inactivated states of the channel. Residues from the S2 and S3 helices are key determinants of isoform selectivity, and bound phospholipids implicate the membrane as a modulator of channel function and pharmacology. Our results help to elucidate the molecular basis of voltage sensing and establish structural blueprints to design selective Nav channel antagonists.

  5. Efficacy of phosphatidylinositol-3 kinase inhibitors with diverse isoform selectivity profiles for inhibiting the survival of chronic lymphocytic leukemia cells.

    PubMed

    Göckeritz, Elisa; Kerwien, Susan; Baumann, Michael; Wigger, Marion; Vondey, Verena; Neumann, Lars; Landwehr, Thomas; Wendtner, Clemens M; Klein, Christian; Liu, Ningshu; Hallek, Michael; Frenzel, Lukas P; Krause, Günter

    2015-11-01

    Pharmacological inhibition of phosphatiylinositide-3-kinase (PI3K)-mediated signaling holds great promise for treating chronic lymphocytic leukemia (CLL). Therefore we assessed three structurally related PI3K inhibitors targeting the PI3K-δ isoform for their ability to inhibit the survival of freshly isolated CLL cells. The purely PI3K-δ-selective inhibitor idelalisib was compared to copanlisib (BAY 80-6946) and duvelisib (IPI-145), with isoform target profiles that additionally include PI3K-α or PI3K-γ, respectively. The concentrations leading to half-maximal reduction of the survival of CLL cells were more than ten-fold lower for copanlisib than for idelalisib and duvelisib. At concentrations reflecting the biological availability of the different inhibitors, high levels of apoptotic response among CLL samples were attained more consistently with copanlisib than with idelalisib. Copanlisib selectively reduced the survival of CLL cells compared to T cells and to B cells from healthy donors. In addition copanlisib and duvelisib impaired the migration of CLL cells towards CXCL12 to a greater extent than equimolar idelalisib. Similarly copanlisib and duvelisib reduced the survival of CLL cells in co-cultures with the bone marrow stroma cell line HS-5 more strongly than idelalisib. Survival inhibition by copanlisib and idelalisib was enhanced by the monoclonal CD20 antibodies rituximab and obinutuzumab (GA101), while antibody-dependent cellular cytotoxicity mediated by alemtuzumab and peripheral blood mononuclear cells was not substantially impaired by both PI3K inhibitors for the CLL-derived JVM-3 cell line as target cells. Taken together, targeting the α- and δ- p110 isoforms with copanlisib may be a useful strategy for the treatment of CLL and warrants further clinical investigation.

  6. The γ-Protocadherin-C3 isoform inhibits canonical Wnt signalling by binding to and stabilizing Axin1 at the membrane

    PubMed Central

    Mah, Kar Men; Houston, Douglas W.; Weiner, Joshua A.

    2016-01-01

    The 22 γ-Protocadherin (γ-Pcdh) adhesion molecules encoded by the Pcdhg gene cluster play critical roles in nervous system development, including regulation of dendrite arborisation, neuronal survival, and synaptogenesis. Recently, they have been implicated in suppression of tumour cell growth by inhibition of canonical Wnt signalling, though the mechanisms through which this occurs remain unknown. Here, we show differential regulation of Wnt signalling by individual γ-Pcdhs: The C3 isoform uniquely inhibits the pathway, whilst 13 other isoforms upregulate signalling. Focusing on the C3 isoform, we show that its unique variable cytoplasmic domain (VCD) is the critical one for Wnt pathway inhibition. γ-Pcdh-C3, but not other isoforms, physically interacts with Axin1, a key component of the canonical Wnt pathway. The C3 VCD competes with Dishevelled for binding to the DIX domain of Axin1, which stabilizes Axin1 at the membrane and leads to reduced phosphorylation of Wnt co-receptor Lrp6. Finally, we present evidence that Wnt pathway activity can be modulated up (by γ-Pcdh-A1) or down (by γ-Pcdh-C3) in the cerebral cortex in vivo, using conditional transgenic alleles. Together, these data delineate opposing roles for γ-Pcdh isoforms in regulating Wnt signalling and identify Axin1 as a novel protein interactor of the widely-expressed γ-Pcdh-C3 isoform. PMID:27530555

  7. Evaluation and Comparison of the Inhibition Effect of Astragaloside IV and Aglycone Cycloastragenol on Various UDP-Glucuronosyltransferase (UGT) Isoforms.

    PubMed

    Ran, Ruixue; Zhang, Chunze; Li, Rongshan; Chen, Bowei; Zhang, Weihua; Zhao, Zhenying; Fu, Zhiwei; Du, Zuo; Du, Xiaolang; Yang, Xiaolong; Fang, Zhongze

    2016-11-29

    As one of the main active ingredients from Radix Astragali (RA), orally dosed astragaloside IV (AST) is easily transformed to sapogenin-cycloastragenol (CAG) by deglycosylation in the gastrointestinal tract. Because the potential adverse effects of AST and CAG remain unclear, the present study in this article was carried out to investigate the inhibition effects of AST and CAG on UDP-glucuronosyltransferases (UGTs) to explore potential clinical toxicity. An in vitro UGTs incubation mixture was employed to study the inhibition of AST and CAG towards UGT isoforms. Concentrations of 100 μM for each compound were used to initially screen the inhibitory efficiency. Deglycosylation of AST to CAG could strongly increase the inhibitory effects towards almost all of the tested UGT isoforms, with an IC50 of 0.84 μM and 11.28 μM for UGT1A8 and UGT2B7, respectively. Ulteriorly, the inhibition type and kinetics of CAG towards UGT1A8 and UGT2B7 were evaluated depending on the initial screening results. Data fitting using Dixon and Lineweaver-Burk plots demonstrated that CAG competitively inhibited UGT1A8 and noncompetitively inhibited UGT2B7. From the second plot drawn with the slopes from the Lineweaver-Burk plot versus the concentrations of CAG, the inhibition constant (Ki) was calculated to be 0.034 μM and 20.98 μM for the inhibition of UGT1A8 and UGT2B7, respectively. Based on the [I]/Ki standard ([I]/Ki < 0.1, low possibility; 1 > [I]/Ki > 0.1, medium possibility; [I]/Ki > 1, high possibility), it was successfully predicted here that an in vivo herb-drug interaction between AST/CAG and drugs mainly undergoing UGT1A8- or UGT2B7-catalyzed metabolism might occur when the plasma concentration of CAG is above 0.034 μM and 20.98 μM, respectively.

  8. Inhibition of class IA PI3K enzymes in non-small cell lung cancer cells uncovers functional compensation among isoforms.

    PubMed

    Stamatkin, Christopher; Ratermann, Kelley L; Overley, Colleen W; Black, Esther P

    2015-01-01

    Deregulation of the phosphatidylinositol 3-kinase (PI3K) pathway is central to many human malignancies while normal cell proliferation requires pathway functionality. Although inhibitors of the PI3K pathway are in clinical trials or approved for therapy, an understanding of the functional activities of pathway members in specific malignancies is needed. In lung cancers, the PI3K pathway is often aberrantly activated by mutation of genes encoding EGFR, KRAS, and PIK3CA proteins. We sought to understand whether class IA PI3K enzymes represent rational therapeutic targets in cells of non-squamous lung cancers by exploring pharmacological and genetic inhibitors of PI3K enzymes in a non-small cell lung cancer (NSCLC) cell line system. We found that class IA PI3K enzymes were expressed in all cell lines tested, but treatment of NSCLC lines with isoform-selective inhibitors (A66, TGX-221, CAL-101 and IC488743) had little effect on cell proliferation or prolonged inhibition of AKT activity. Inhibitory pharmacokinetic and pharmacodynamic responses were observed using these agents at non-isoform selective concentrations and with the pan-class I (ZSTK474) agent. Response to pharmacological inhibition suggested that PI3K isoforms may functionally compensate for one another thus limiting efficacy of single agent treatment. However, combination of ZSTK474 and an EGFR inhibitor (erlotinib) in NSCLC resistant to each single agent reduced cellular proliferation. These studies uncovered unanticipated cellular responses to PI3K isoform inhibition in NSCLC that does not correlate with PI3K mutations, suggesting that patients bearing tumors with wildtype EGFR and KRAS are unlikely to benefit from inhibitors of single isoforms but may respond to pan-isoform inhibition.

  9. Inhibition of UDP-Glucuronosyltransferase (UGT) Isoforms by Arctiin and Arctigenin.

    PubMed

    Zhang, Hui; Zhao, Zhenying; Wang, Tao; Wang, Yijia; Cui, Xiao; Zhang, Huijuan; Fang, Zhong-Ze

    2016-07-01

    Arctiin is the major pharmacological ingredient of Fructus Arctii, and arctigenin is the metabolite of arctiin formed via the catalysis of human intestinal bacteria. The present study aims to investigate the inhibition profile of arctiin and arctigenin on important phase II drug-metabolizing enzymes UDP-glucuronosyltransferases (UGTs), indicating the possible herb-drug interaction. In vitro screening experiment showed that 100 μM of arctiin and arctigenin inhibited the activity of UGT1A3, 1A9, 2B7, and 2B15. Homology modeling-based in silico docking of arctiin and arctigenin into the activity cavity of UGT2B15 showed that hydrogen bonds and hydrophobic interactions contributed to the strong binding free energy of arctiin (-8.14 kcal/mol) and arctigenin (-8.43 kcal/mol) with UGT2B15. Inhibition kinetics study showed that arctiin and arctigenin exerted competitive and noncompetitive inhibition toward UGT2B15, respectively. The inhibition kinetic parameters (Ki ) were calculated to be 16.0 and 76.7 μM for the inhibition of UGT2B15 by arctiin and arctigenin, respectively. Based on the plasma concentration of arctiin and arctigenin after administration of 100 mg/kg of arctiin, the [I]/Ki values were calculated to be 0.3 and 0.007 for arctiin and arctigenin, respectively. Based on the inhibition evaluation standard ([I]/Ki  < 0.1, low possibility; 0.1 < [I]/Ki  < 1, medium possibility; [I]/Ki  > 1, high possibility), arctiin might induce drug-drug interaction with medium possibility. Based on these results, clinical monitoring the utilization of Fructus Arctii is very important and necessary. Copyright © 2016 John Wiley & Sons, Ltd.

  10. Inhibition of PaCaMKII-E isoform in the dorsal unpaired median neurosecretory cells of cockroach reduces nicotine- and clothianidin-induced currents.

    PubMed

    List, Olivier; Calas-List, Delphine; Taillebois, Emiliane; Juchaux, Marjorie; Heuland, Emilie; Thany, Steeve H

    2014-08-01

    Cellular responses to Ca(2+) require intermediary proteins such as calcium/calmodulin-dependent protein kinase II (CaMKII), which transduces the signal into downstream effects. We recently demonstrated that the cockroach genome encodes five different CaMKII isoforms, and only PaCaMKII-E isoform is specifically expressed in the dorsal unpaired median neurosecretory cells. In the present study, using antisense oligonucleotides, we demonstrated that PaCaMKII-E isoform inhibition reduced nicotine-induced currents through α-bungarotoxin-sensitive and -insensitive nicotinic acetylcholine receptor subtypes. Specifically, PaCaMKII-E isoform is sufficient to repress nicotinic current amplitudes as a result of its depression by antisense oligonucleotides. Similar results were found using the neonicotinoid insecticide clothianidin, which acted as a full agonist of dorsal unpaired median neuron nicotinic acetylcholine receptors. Clothianidin current amplitudes are strongly reduced under bath application of PaCaMKII-E antisense oligonucleotides but no significant results are found with α-bungarotoxin co-applied, demonstrating that CaMKII-E isoform affects nicotine currents through α-bungarotoxin-sensitive and -insensitive receptor subtypes whereas clothianidin currents are reduced via α-bungarotoxin-insensitive receptors. In addition, we found that intracellular calcium increase induced by nicotine and clothianidin were reduced by PaCaMKII-E antisense oligonucleotides, demonstrating that intracellular calcium increase induced by nicotine and clothianidin are affected by PaCaMKII-E inhibition. Cellular responses to Ca(2+) require intermediary proteins such as calcium/calmodulin-dependent protein kinase II (CaMKII). We recently demonstrated that the cockroach genome encodes five different CaMKII isoforms and only PaCaMKII-E isoform was specifically expressed in the dorsal unpaired median neurosecretory cells. Here we show that specific inhibition of PaCaMKII-E isoform is

  11. Differential 3-bromopyruvate inhibition of cytosolic and mitochondrial human serine hydroxymethyltransferase isoforms, key enzymes in cancer metabolic reprogramming.

    PubMed

    Paiardini, Alessandro; Tramonti, Angela; Schirch, Doug; Guiducci, Giulia; di Salvo, Martino Luigi; Fiascarelli, Alessio; Giorgi, Alessandra; Maras, Bruno; Cutruzzolà, Francesca; Contestabile, Roberto

    2016-11-01

    The cytosolic and mitochondrial isoforms of serine hydroxymethyltransferase (SHMT1 and SHMT2, respectively) are well-recognized targets of cancer research, since their activity is critical for purine and pyrimidine biosynthesis and because of their prominent role in the metabolic reprogramming of cancer cells. Here we show that 3-bromopyruvate (3BP), a potent novel anti-tumour agent believed to function primarily by blocking energy metabolism, differentially inactivates human SHMT1 and SHMT2. SHMT1 is completely inhibited by 3BP, whereas SHMT2 retains a significant fraction of activity. Site directed mutagenesis experiments on SHMT1 demonstrate that selective inhibition relies on the presence of a cysteine residue at the active site of SHMT1 (Cys204) that is absent in SHMT2. Our results show that 3BP binds to SHMT1 active site, forming an enzyme-3BP complex, before reacting with Cys204. The physiological substrate l-serine is still able to bind at the active site of the inhibited enzyme, although catalysis does not occur. Modelling studies suggest that alkylation of Cys204 prevents a productive binding of l-serine, hampering interaction between substrate and Arg402. Conversely, the partial inactivation of SHMT2 takes place without the formation of a 3BP-enzyme complex. The introduction of a cysteine residue in the active site of SHMT2 by site directed mutagenesis (A206C mutation), at a location corresponding to that of Cys204 in SHMT1, yields an enzyme that forms a 3BP-enzyme complex and is completely inactivated. This work sets the basis for the development of selective SHMT1 inhibitors that target Cys204, starting from the structure and reactivity of 3BP.

  12. Effect of antipsychotic drugs on human liver cytochrome P-450 (CYP) isoforms in vitro: preferential inhibition of CYP2D6.

    PubMed

    Shin, J G; Soukhova, N; Flockhart, D A

    1999-09-01

    The ability of antipsychotic drugs to inhibit the catalytic activity of five cytochrome P-450 (CYP) isoforms was compared using in vitro human liver microsomal preparations to evaluate the relative potential of these drugs to inhibit drug metabolism. The apparent kinetic parameters for enzyme inhibition were determined by nonlinear regression analysis of the data. All antipsychotic drugs tested competitively inhibited dextromethorphan O-demethylation, a selective marker for CYP2D6, in a concentration-dependent manner. Thioridazine and perphenazine were the most potent, with IC(50) values (2.7 and 1.5 microM) that were comparable to that of quinidine (0.52 microM). The estimated K(i) values for CYP2D6-catalyzing dextrorphan formation were ranked in the following order: perphenazine (0.8 microM), thioridazine (1.4 microM), chlorpromazine (6.4 microM), haloperidol (7.2 microM), fluphenazine (9.4 microM), risperidone (21.9 microM), clozapine (39.0 microM), and cis-thiothixene (65.0 microM). No remarkable inhibition of other CYP isoforms was observed except for moderate inhibition of CYP1A2-catalyzed phenacetin O-deethylation by fluphenazine (K(i) = 40.2 microM) and perphenazine (K(i) = 65.1). The estimated K(i) values for the inhibition of CYP2C9, 2C19, and 3A were >300 microM in almost all antipsychotics tested. These results suggest that antipsychotic drugs exhibit a striking selectivity for CYP2D6 compared with other CYP isoforms. This may reflect a remarkable commonality of structure between the therapeutic targets for these drugs, the transporters, and metabolic enzymes that distribute and eliminate them. Clinically, coadministration of these medicines with drugs that are primarily metabolized by CYP2D6 may result in significant drug interactions.

  13. The p63 Protein Isoform ΔNp63α Inhibits Epithelial-Mesenchymal Transition in Human Bladder Cancer Cells

    PubMed Central

    Tran, Mai N.; Choi, Woonyoung; Wszolek, Matthew F.; Navai, Neema; Lee, I-Ling C.; Nitti, Giovanni; Wen, Sijin; Flores, Elsa R.; Siefker-Radtke, Arlene; Czerniak, Bogdan; Dinney, Colin; Barton, Michelle; McConkey, David J.

    2013-01-01

    Epithelial-mesenchymal transition (EMT) is a physiological process that plays important roles in tumor metastasis, “stemness,” and drug resistance. EMT is typically characterized by the loss of the epithelial marker E-cadherin and increased expression of EMT-associated transcriptional repressors, including ZEB1 and ZEB2. The miR-200 family and miR-205 prevent EMT through suppression of ZEB1/2. p53 has been implicated in the regulation of miR-200c, but the mechanisms controlling miR-205 expression remain elusive. Here we report that the p53 family member and p63 isoform, ΔNp63α, promotes miR-205 transcription and controls EMT in human bladder cancer cells. ΔNp63α, E-cadherin and miR-205 were coexpressed in a panel of bladder cancer cell lines (n = 28) and a cohort of primary bladder tumors (n = 98). Stable knockdown of ΔNp63α in the “epithelial” bladder cancer cell line UM-UC6 decreased the expression of miR-205 and induced the expression of ZEB1/2, effects that were reversed by expression of exogenous miR-205. Conversely, overexpression of ΔNp63α in the “mesenchymal” bladder cancer cell line UM-UC3 induced miR-205 and suppressed ZEB1/2. ΔNp63α knockdown reduced the expression of the primary and mature forms of miR-205 and the miR-205 “host” gene (miR-205HG) and decreased binding of RNA Pol II to the miR-205HG promoter, inhibiting miR-205HG transcription. Finally, high miR-205 expression was associated with adverse clinical outcomes in bladder cancer patients. Together, our data demonstrate that ΔNp63α-mediated expression of miR-205 contributes to the regulation of EMT in bladder cancer cells and identify miR-205 as a molecular marker of the lethal subset of human bladder cancers. PMID:23239884

  14. Enhanced expression of epithelial sodium channels causes salt-induced hypertension in mice through inhibition of the α2-isoform of Na+, K+-ATPase.

    PubMed

    Leenen, Frans H H; Hou, Xiaohong; Wang, Hong-Wei; Ahmad, Monir

    2015-05-01

    Knockout of the Nedd4-2 gene in mice results in overexpression of epithelial sodium channels (ENaC) on the plasma membrane in the kidney, choroid plexus and brain nuclei. These mice exhibit enhanced pressor responses to CSF [Na(+)] as well as dietary salt-induced hypertension which both can be blocked by central infusion of the ENaC blocker benzamil. Functional studies suggest that ENaC activation in the CNS results in release of endogenous ouabain (EO) and inhibition of the α2-isoform of Na(+), K(+)-ATPase. To test this concept more specifically, we studied Nedd4-2(-/-) mice expressing the ouabain-resistant α2R/R-isoform of Na(+), K(+)-ATPase. Intracerebroventricular (icv) infusion of Na(+)-rich aCSF (225 mmol/L Na(+) at 0.4 μL/min) increased MAP by 10-15 mmHg in wild-type mice and by 25-30 mmHg in Nedd4-2(-/-) mice, but by only ~5 mmHg in α2R/R and in α2R/R/Nedd4-2(-/-) mice. Icv infusion of EO-binding Fab fragments also blocked the BP response in Nedd4-2(-/-) mice. In Nedd4-2(-/-) mice, 8% high-salt diet increased MAP by 25-30 mmHg, but in α2R/R/Nedd4-2(-/-) mice, it increased by only 5-10 mmHg. In contrast, Nedd4-2(-/-) or α2R/R did not affect the hypertension caused by sc infusion of Ang II. These findings substantiate the concept that enhanced ENaC activity causes salt-induced pressor responses mainly through EO inhibiting the α2-isoform of Na(+), K(+)-ATPase in the brain.

  15. Isoform-selective phosphoinositide 3'-kinase inhibitors inhibit CXCR4 signaling and overcome stromal cell-mediated drug resistance in chronic lymphocytic leukemia: a novel therapeutic approach.

    PubMed

    Niedermeier, Matthias; Hennessy, Bryan T; Knight, Zachary A; Henneberg, Marina; Hu, Jianhua; Kurtova, Antonina V; Wierda, William G; Keating, Michael J; Shokat, Kevan M; Burger, Jan A

    2009-05-28

    Phosphoinositide 3-kinases (PI3Ks) are among the most frequently activated signaling pathways in cancer. In chronic lymphocytic leukemia (CLL), signals from the microenvironment are critical for expansion of the malignant B cells, and cause constitutive activation of PI3Ks. CXCR4 is a key receptor for CLL cell migration and adhesion to marrow stromal cells (MSCs). Because of the importance of CXCR4 and PI3Ks for CLL-microenvironment cross-talk, we investigated the activity of novel, isoform-selective PI3K inhibitors that target different isoforms of the p110-kDa subunit. Inhibition with p110alpha inhibitors (PIK-90 and PI-103) resulted in a significant reduction of chemotaxis and actin polymerization to CXCL12 and reduced migration beneath MSC (pseudoemperipolesis). Western blot and reverse phase protein array analyses consistently demonstrated that PIK-90 and PI-103 inhibited phosphorylation of Akt and S6, whereas p110delta or p110beta/p110delta inhibitors were less effective. In suspension and MSC cocultures, PI-103 and PIK-90 were potent inducers of CLL cell apoptosis. Moreover, these p110alpha inhibitors enhanced the cytotoxicity of fludarabine and reversed the protective effect of MSC on fludarabine-induced apoptosis. Collectively, our data demonstrate that p110alpha inhibitors antagonize stromal cell-derived migration, survival, and drug-resistance signals and therefore provide a rational to explore the therapeutic activity of these promising agents in CLL.

  16. Polysaccharide peptides from Coriolus versicolor competitively inhibit tolbutamide 4-hydroxylation in specific human CYP2C9 isoform and pooled human liver microsomes.

    PubMed

    Yeung, John H K; Or, Penelope M Y

    2011-10-15

    Polysaccharide peptide (PSP), isolated from COV-1 strain of Coriolus versicolor, is commonly used as an adjunct in cancer chemotherapy in China. Previous studies have shown that PSP decreased antipyrine clearance and inhibited CYP2C11-mediated tolbutamide 4-hydroxylation in the rat both in vitro and in vivo. In this study, the effects of water extractable fraction of PSP on tolbutamide 4-hydroxylation was investigated in pooled human liver microsomes and in specific human CYP2C9 isoform. PSP (2.5-20μM) dose-dependently decreased the biotransformation of tolbutamide to 4-hydroxy-tolbutamide. Enzyme kinetics studies showed inhibition of tolbutamide 4-hydroxylase activity was competitive and concentration-dependent. In pooled human liver microsomes, PSP had a K(i) value of 14.2μM compared to sulfaphenazole, a human CYP2C9 inhibitor, showed a K(i) value of 0.32μM. In human CYP2C9 isoform, the K(i) value of PSP was 29.5μM and the K(i) value of sulfaphenazole was 0.04μM. This study demonstrated that PSP can competitively inhibit tolbutamide 4-hydroxylation in both pooled human liver microsomes and specific human CYP2C9 in vitro. This study compliments previous findings in the rat that PSP can inhibit human tolbutamide 4-hydroxylase, but the relatively high K(i) values in human CYP2C9 would suggest a low potential for PSP to cause herb-drug interaction.

  17. Aspirin-induced histone acetylation in endothelial cells enhances synthesis of the secreted isoform of netrin-1 thus inhibiting monocyte vascular infiltration

    PubMed Central

    Passacquale, Gabriella; Phinikaridou, Alkystis; Warboys, Christina; Cooper, Margaret; Lavin, Begona; Alfieri, Alessio; Andia, Marcelo E; Botnar, Rene M; Ferro, Albert

    2015-01-01

    Background and Purpose There are conflicting data regarding whether netrin-1 retards or accelerates atherosclerosis progression, as it can lead either to monocyte repulsion from or retention within plaques depending on its cellular source. We investigated the effect of aspirin, which is widely used in cardiovascular prophylaxis, on the synthesis of different isoforms of netrin-1 by endothelial cells under pro-inflammatory conditions, and defined the net effect of aspirin-dependent systemic modulation of netrin-1 on atherosclerosis progression. Experimental Approach Netrin-1 synthesis was studied in vitro using human endothelial cells stimulated with TNF-α, with or without aspirin treatment. In vivo experiments were conducted in ApoE−/− mice fed with a high-fat diet (HFD), receiving either aspirin or clopidogrel. Key Results TNF-α-induced NF-κB activation up-regulated the nuclear isoform of netrin-1, while simultaneously reducing secreted netrin-1. Down-regulation of the secreted isoform compromised the chemorepellent action of the endothelium against monocyte chemotaxis. Aspirin counteracted TNF-α-mediated effects on netrin-1 synthesis by endothelial cells through COX-dependent inhibition of NF-κB and concomitant histone hyperacetylation. Administration of aspirin to ApoE−/− mice on HFD increased blood and arterial wall levels of netrin-1 independently of its effects on platelets, accompanied by reduced plaque size and content of monocytes/macrophages, compared with untreated or clopidogrel-treated mice. In vivo blockade of netrin-1 enhanced monocyte plaque infiltration in aspirin-treated ApoE−/− mice. Conclusions and Implications Aspirin counteracts down-regulation of secreted netrin-1 induced by pro-inflammatory stimuli in endothelial cells. The aspirin-dependent increase of netrin-1 in ApoE−/− mice exerts anti-atherogenic effects by preventing arterial accumulation of monocytes. PMID:25824964

  18. Neuropeptide specificity and inhibition of recombinant isoforms of the endopeptidase 3.4.24.16 family: comparison with the related recombinant endopeptidase 3.4.24.15.

    PubMed

    Rioli, V; Kato, A; Portaro, F C; Cury, G K; te Kaat, K; Vincent, B; Checler, F; Camargo, A C; Glucksman, M J; Roberts, J L; Hirose, S; Ferro, E S

    1998-09-08

    Endopeptidase EC 3.4.24.16 (EP24.16c, neurolysin) and thimet oligopeptidase EC 3.4.24.15 are close related members of a large family of metalloproteases. Besides their cytosolic and membrane bound form, endopeptidase EC 3.4.24.16 appears to be present in the inner membrane of the mitochondria (EP24.16m). We have overexpressed two porcine EP24.16 isoforms in E. coli and purified the recombinant proteins to homogeneity. We show here that these peptidases hydrolyse a series of neuropeptides with similar rates and at sites reminiscent of those elicited by classically purified human brain EP24.16c. All neuropeptides, except neurotensin, were similarly cleaved by recombinant endopeptidase 3.4.24.15 (EP24.15, thimet oligopeptidase), another zinc-containing metalloenzyme structurally related to EP24.16. These two EP24.16 isoforms were drastically inhibited by Pro-Ile and dithiothreitol and remained unaffected by a specific carboalkyl inhibitor (CFP-AAY-pAb) directed toward the related EP24.15. The present purification procedure of EP24.16 should allow to establish, by mutagenesis analysis, the mechanistic properties of the enzyme.

  19. The high mobility group protein HMG I(Y) can stimulate or inhibit DNA binding of distinct transcription factor ATF-2 isoforms.

    PubMed

    Du, W; Maniatis, T

    1994-11-22

    The high mobility group protein HMG I(Y) stimulates the binding of a specific isoform of the activating transcription factor 2 (ATF-2(195)) to the interferon beta (IFN-beta) gene promoter. HMG I(Y) specifically interacts with the basic-leucine zipper region of ATF-2(195), and HMG I(Y) binds to two sites immediately flanking the ATF-2 binding site of the IFN-beta promoter. Here, we show that HMG I(Y) can stimulate the binding of ATF-2(195), at least in part, by promoting ATF-2 dimerization. In addition, we report the characterization of a naturally occurring isoform of ATF-2 (ATF-2(192)) that binds specifically to the IFN-beta promoter but is unable to interact with HMG I(Y). Remarkably, HMG I(Y) inhibits the binding of ATF-2(192) to the IFN-beta promoter. Thus, the ability of HMG I(Y) to specifically interact with ATF-2 correlates with its ability to stimulate ATF-2 binding to the IFN-beta promoter. Comparisons of the amino acid sequences of the basic-leucine zipper domains of ATF-2(195) and ATF-2(192) suggest that HMG I(Y) interacts with a short stretch of basic amino acids near the amino terminus of the basic-leucine zipper domain of ATF-2(195).

  20. Towards selective inhibition of histone deacetylase isoforms: what has been achieved, where we are and what will be next.

    PubMed

    Thaler, Florian; Mercurio, Ciro

    2014-03-01

    Histone deacetylases (HDACs) are widely studied targets for the treatment of cancer and other diseases. Up to now, over twenty HDAC inhibitors have entered clinical studies and two of them have already reached the market, namely the hydroxamic acid derivative SAHA (vorinostat, Zolinza) and the cyclic depsipeptide FK228 (romidepsin, Istodax) that have been approved for the treatment of cutaneous T-cell lymphoma (CTCL). A common aspect of the first HDAC inhibitors is the absence of any particular selectivity towards specific isozymes. Some of molecules resulted to be “pan”-HDAC inhibitors, while others are class I selective. In the meantime, the knowledge of HDAC biology has continuously progressed. Key advances in the structural biology of various isozymes, reliable molecular homology models as well as suitable biological assays have provided new tools for drug discovery activities. This Minireview aims at surveying these recent developments as well as the design, synthesis and biological characterization of isoform-selective derivatives.

  1. Inhibition of insulin receptor gene expression and insulin signaling by fatty acid: interplay of PKC isoforms therein.

    PubMed

    Dey, Debleena; Mukherjee, Mohua; Basu, Dipanjan; Datta, Malabika; Roy, Sib Sankar; Bandyopadhyay, Arun; Bhattacharya, Samir

    2005-01-01

    Fatty acids are known to play a key role in promoting the loss of insulin sensitivity causing insulin resistance and type 2 diabetes. However, underlying mechanism involved here is still unclear. Incubation of rat skeletal muscle cells with palmitate followed by I(125)- insulin binding to the plasma membrane receptor preparation demonstrated a two-fold decrease in receptor occupation. In searching the cause for this reduction, we found that palmitate inhibition of insulin receptor (IR) gene expression effecting reduced amount of IR protein in skeletal muscle cells. This was followed by the inhibition of insulin-stimulated IRbeta tyrosine phosphorylation that consequently resulted inhibition of insulin receptor substrate 1 (IRS 1) and IRS 1 associated phosphatidylinositol-3 kinase (PI3 Kinase), phosphoinositide dependent kinase-1 (PDK 1) phosphorylation. PDK 1 dependent phosphorylation of PKCzeta and Akt/PKB were also inhibited by palmitate. Surprisingly, although PKCepsilon phosphorylation is PDK1 dependent, palmitate effected its constitutive phosphorylation independent of PDK1. Time kinetics study showed translocation of palmitate induced phosphorylated PKCepsilon from cell membrane to nuclear region and its possible association with the inhibition of IR gene transcription. Our study suggests one of the pathways through which fatty acid can induce insulin resistance in skeletal muscle cell.

  2. The lethal response to Cdk1 inhibition depends on sister chromatid alignment errors generated by KIF4 and isoform 1 of PRC1

    PubMed Central

    Voets, Erik; Marsman, Judith; Demmers, Jeroen; Beijersbergen, Roderick; Wolthuis, Rob

    2015-01-01

    Cyclin-dependent kinase 1 (Cdk1) is absolutely essential for cell division. Complete ablation of Cdk1 precludes the entry of G2 phase cells into mitosis, and is early embryonic lethal in mice. Dampening Cdk1 activation, by reducing gene expression or upon treatment with cell-permeable Cdk1 inhibitors, is also detrimental for proliferating cells, but has been associated with defects in mitotic progression, and the formation of aneuploid daughter cells. Here, we used a large-scale RNAi screen to identify the human genes that critically determine the cellular toxicity of Cdk1 inhibition. We show that Cdk1 inhibition leads to fatal sister chromatid alignment errors and mitotic arrest in the spindle checkpoint. These problems start early in mitosis and are alleviated by depletion of isoform 1 of PRC1 (PRC1-1), by gene ablation of its binding partner KIF4, or by abrogation of KIF4 motor activity. Our results show that, normally, Cdk1 activity must rise above the level required for mitotic entry. This prevents KIF4-dependent PRC1-1 translocation to astral microtubule tips and safeguards proper chromosome congression. We conclude that cell death in response to Cdk1 inhibitors directly relates to chromosome alignment defects generated by insufficient repression of PRC1-1 and KIF4 during prometaphase. PMID:26423135

  3. Regulation of the meiosis-inhibited protein kinase, a p38(MAPK) isoform, during meiosis and following fertilization of seastar oocytes.

    PubMed

    Morrison, D L; Yee, A; Paddon, H B; Vilimek, D; Aebersold, R; Pelech, S L

    2000-11-03

    A p38(MAPK) homolog Mipk (meiosis-inhibited protein kinase) was cloned from seastar oocytes. This 40-kDa protein shares approximately 65% amino acid identity with mammalian p38-alpha isoforms. Mipk was one of the major tyrosine-phosphorylated proteins in immature oocytes arrested at the G(2)/M transition of meiosis I. The tyrosine phosphorylation of Mipk was increased in response to anisomycin, heat, and osmotic shock of oocytes. During 1-methyladenine-induced oocyte maturation, Mipk underwent tyrosine dephosphorylation and remained dephosphorylated in mature oocytes and during the early mitotic cell divisions until approximately 12 h after fertilization. At the time of differentiation and acquisition of G phases in the developing embryos, Mipk was rephosphorylated on tyrosine. In oocytes that were microinjected with Mipk antisense oligonucleotides and subsequently were allowed to mature and become fertilized, differentiation was blocked. Because MipK antisense oligonucleotides and a dominant-negative (K62R)Mipk when microinjected into immature oocytes failed to induce germinal vesicle breakdown, inhibition of Mipk function was not sufficient by itself to cause oocyte maturation. These findings point to a putative role for Mipk in cell cycle control as a G-phase-promoting factor.

  4. An autoinhibitory peptide from the erythrocyte Ca-ATPase aggregates and inhibits both muscle Ca-ATPase isoforms.

    PubMed Central

    Reddy, L G; Shi, Y; Kutchai, H; Filoteo, A G; Penniston, J T; Thomas, D D

    1999-01-01

    We have studied the effects of C28R2, a basic peptide derived from the autoinhibitory domain of the plasma membrane Ca-ATPase, on enzyme activity, oligomeric state, and E1-E2 conformational equilibrium of the Ca-ATPase from skeletal and cardiac sarcoplasmic reticulum (SR). Time-resolved phosphorescence anisotropy (TPA) was used to determine changes in the distribution of Ca-ATPase among its different oligomeric species in SR. C28R2, at a concentration of 1-10 microM, inhibits the Ca-ATPase activity of both skeletal and cardiac SR (CSR). In skeletal SR, this inhibition by C28R2 is much greater at low (0.15 microM) than at high (10 microM) Ca2+, whereas in CSR the inhibition is the same at low and high Ca2+. The effects of the peptide on the rotational mobility of the Ca-ATPase correlated well with function, indicating that C28R2-induced protein aggregation and Ca-ATPase inhibition are much more Ca-dependent in skeletal than in CSR. In CSR at low Ca2+, phospholamban (PLB) antibody (functionally equivalent to PLB phosphorylation) increased the inhibitory effect of C28R2 slightly. Fluorescence of fluorescein 5-isothiocyanate-labeled SR suggests that C28R2 stabilizes the E1 conformation of the Ca-ATPase in skeletal SR, whereas in CSR it stabilizes E2. After the addition of PLB antibody, C28R2 still stabilizes the E2 conformational state of CSR. Therefore, we conclude that C28R2 affects Ca-ATPase activity, conformation, and self-association differently in cardiac and skeletal SR and that PLB is probably not responsible for the differences. PMID:10354431

  5. Structural and functional characterization of an arylamine N-acetyltransferase from the pathogen Mycobacterium abscessus: differences from other mycobacterial isoforms and implications for selective inhibition.

    PubMed

    Cocaign, Angélique; Kubiak, Xavier; Xu, Ximing; Garnier, Guillaume; Li de la Sierra-Gallay, Inès; Chi-Bui, Linh; Dairou, Julien; Busi, Florent; Abuhammad, Areej; Haouz, Ahmed; Dupret, Jean Marie; Herrmann, Jean Louis; Rodrigues-Lima, Fernando

    2014-11-01

    Mycobacterium abscessus is the most pathogenic rapid-growing mycobacterium and is one of the most resistant organisms to chemotherapeutic agents. However, structural and functional studies of M. abscessus proteins that could modify/inactivate antibiotics remain nonexistent. Here, the structural and functional characterization of an arylamine N-acetyltransferase (NAT) from M. abscessus [(MYCAB)NAT1] are reported. This novel prokaryotic NAT displays significant N-acetyltransferase activity towards aromatic substrates, including antibiotics such as isoniazid and p-aminosalicylate. The enzyme is endogenously expressed and functional in both the rough and smooth M. abscessus morphotypes. The crystal structure of (MYCAB)NAT1 at 1.8 Å resolution reveals that it is more closely related to Nocardia farcinica NAT than to mycobacterial isoforms. In particular, structural and physicochemical differences from other mycobacterial NATs were found in the active site. Peculiarities of (MYCAB)NAT1 were further supported by kinetic and docking studies showing that the enzyme was poorly inhibited by the piperidinol inhibitor of mycobacterial NATs. This study describes the first structure of an antibiotic-modifying enzyme from M. abscessus and provides bases to better understand the substrate/inhibitor-binding specificities among mycobacterial NATs and to identify/optimize specific inhibitors. These data should also contribute to the understanding of the mechanisms that are responsible for the pathogenicity and extensive chemotherapeutic resistance of M. abscessus.

  6. Plasma membrane Ca2+-ATPase isoform 4 antagonizes cardiac hypertrophy in association with calcineurin inhibition in rodents.

    PubMed

    Wu, Xu; Chang, Baojun; Blair, N Scott; Sargent, Michelle; York, Allen J; Robbins, Jeffrey; Shull, Gary E; Molkentin, Jeffery D

    2009-04-01

    How Ca2+-dependent signaling effectors are regulated in cardiomyocytes, given the extreme cytoplasmic Ca2+ concentration changes that underlie contraction, remains unknown. Cardiomyocyte plasma membrane Ca2+-ATPase (PMCA) extrudes Ca2+ but has little effect on excitation-contraction coupling, suggesting its potential role in controlling Ca2+-dependent signaling effectors such as calcineurin. We generated cardiac-specific inducible PMCA4b transgenic mice that displayed normal global Ca2+ transient and cellular contraction levels and reduced cardiac hypertrophy following transverse aortic constriction (TAC) or phenylephrine/Ang II infusion, but showed no reduction in exercise-induced hypertrophy. Transgenic mice were protected from decompensation and fibrosis following long-term TAC. The PMCA4b transgene reduced the hypertrophic augmentation associated with transient receptor potential canonical 3 channel overexpression, but not that associated with activated calcineurin. Furthermore, Pmca4 gene-targeted mice showed increased cardiac hypertrophy and heart failure events after TAC. Physical associations between PMCA4b and calcineurin were enhanced by TAC and by agonist stimulation of cultured neonatal cardiomyocytes. PMCA4b reduced calcineurin nuclear factor of activated T cell-luciferase activity after TAC and in cultured neonatal cardiomyocytes after agonist stimulation. PMCA4b overexpression inhibited cultured cardiomyocyte hypertrophy following agonist stimulation, but much less so in a Ca2+ pumping-deficient PMCA4b mutant. Thus, Pmca4b likely reduces the local Ca2+ signals involved in reactive cardiomyocyte hypertrophy via calcineurin regulation.

  7. Inhibition of PI3K Prevents the Proliferation and Differentiation of Human Lung Fibroblasts into Myofibroblasts: The Role of Class I P110 Isoforms

    PubMed Central

    Conte, Enrico; Fruciano, Mary; Fagone, Evelina; Gili, Elisa; Caraci, Filippo; Iemmolo, Maria; Crimi, Nunzio; Vancheri, Carlo

    2011-01-01

    Idiopathic pulmonary fibrosis (IPF) is a progressive fibroproliferative disease characterized by an accumulation of fibroblasts and myofibroblasts in the alveolar wall. Even though the pathogenesis of this fatal disorder remains unclear, transforming growth factor-β (TGF-β)-induced differentiation and proliferation of myofibroblasts is recognized as a primary event. The molecular pathways involved in TGF-β signalling are generally Smad-dependent yet Smad-independent pathways, including phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt), have been recently proposed. In this research we established ex-vivo cultures of human lung fibroblasts and we investigated the role of the PI3K/Akt pathway in two critical stages of the fibrotic process induced by TGF-β: fibroblast proliferation and differentiation into myofibroblasts. Here we show that the pan-inhibitor of PI3Ks LY294002 is able to abrogate the TGF-β-induced increase in cell proliferation, in α- smooth muscle actin expression and in collagen production besides inhibiting Akt phosphorylation, thus demonstrating the centrality of the PI3K/Akt pathway in lung fibroblast proliferation and differentiation. Moreover, for the first time we show that PI3K p110δ and p110γ are functionally expressed in human lung fibroblasts, in addition to the ubiquitously expressed p110α and β. Finally, results obtained with both selective inhibitors and gene knocking-down experiments demonstrate a major role of p110γ and p110α in both TGF-β-induced fibroblast proliferation and differentiation. This finding suggests that specific PI3K isoforms can be pharmacological targets in IPF. PMID:21984893

  8. Combined Inhibition of Both p110α and p110β Isoforms of Phosphatidylinositol 3-Kinase Is Required for Sustained Therapeutic Effect in PTEN-Deficient, ER(+) Breast Cancer.

    PubMed

    Hosford, Sarah R; Dillon, Lloye M; Bouley, Stephanie J; Rosati, Rachele; Yang, Wei; Chen, Vivian S; Demidenko, Eugene; Morra, Rocco P; Miller, Todd W

    2016-11-30

    Purpose: Determine the roles of the PI3K isoforms p110α and p110β in PTEN-deficient, estrogen receptor α (ER)-positive breast cancer, and the therapeutic potential of isoform-selective inhibitors.Experimental Design: Anti-estrogen-sensitive and -resistant PTEN-deficient, ER(+) human breast cancer cell lines, and mice bearing anti-estrogen-resistant xenografts were treated with the anti-estrogen fulvestrant, the p110α inhibitor BYL719, the p110β inhibitor GSK2636771, or combinations. Temporal response to growth factor receptor-initiated signaling, growth, apoptosis, predictive biomarkers, and tumor volumes were measured.Results: p110β primed cells for response to growth factor stimulation. Although p110β inhibition suppressed cell and tumor growth, dual targeting of p110α/β enhanced apoptosis and provided sustained tumor response. The growth of anti-estrogen-sensitive cells was inhibited by fulvestrant, but fulvestrant inconsistently provided additional therapeutic effects beyond PI3K inhibition alone. Treatment-induced decreases in phosphorylation of AKT and Rb were predictive of therapeutic response. Short-term drug treatment induced tumor cell apoptosis and proliferative arrest to induce tumor regression, whereas long-term treatment only suppressed proliferation to provide durable regression.Conclusions: p110β is the dominant PI3K isoform in PTEN-deficient, ER(+) breast cancer cells. Upon p110β inhibition, p110α did not induce significant reactivation of AKT, but combined targeting of p110α/β most effectively induced apoptosis in vitro and in vivo and provided durable tumor regression. Because apoptosis and tumor regression occurred early but not late in the treatment course, and proliferative arrest was maintained throughout treatment, p110α/β inhibitors may be considered short-term cytotoxic agents and long-term cytostatic agents. Clin Cancer Res; 1-11. ©2016 AACR.

  9. ER egress of invariant chain isoform p35 requires direct binding to MHCII molecules and is inhibited by the NleA virulence factor of enterohaemorrhagic Escherichia coli.

    PubMed

    Cloutier, Maryse; Gauthier, Catherine; Fortin, Jean-Simon; Genève, Laetitia; Kim, Kyungho; Gruenheid, Samantha; Kim, Jinoh; Thibodeau, Jacques

    2015-04-01

    Four invariant chain (Ii) isoforms assist the folding and trafficking of human MHC class II (MHCIIs). The main isoforms, Iip33 and Iip35, assemble in the ER into homo- and/or hetero-trimers. The sequential binding of up to three MHCII αβ heterodimers to Ii trimers results in the formation of pentamers, heptamers and nonamers. MHCIIs are required to overcome the p35-encoded di-arginine (RxR) ER retention motif and to allow anterograde trafficking of the complex. Here, we show that inactivation of the RxR motif requires a direct cis interaction between p35 and the MHCII, precluding ER egress of some unsaturated Ii trimers. Interestingly, as opposed to MHCII/p33 complexes, those including p35 remained in the ER when co-expressed with the NleA protein of enterohaemorrhagic Escherichia coli. Taken together, our results demonstrate that p35 influences distinctively MHCII/Ii assembly and trafficking.

  10. Isoform-selective phosphoinositide 3′-kinase inhibitors inhibit CXCR4 signaling and overcome stromal cell–mediated drug resistance in chronic lymphocytic leukemia: a novel therapeutic approach

    PubMed Central

    Niedermeier, Matthias; Hennessy, Bryan T.; Knight, Zachary A.; Henneberg, Marina; Hu, Jianhua; Kurtova, Antonina V.; Wierda, William G.; Keating, Michael J.; Shokat, Kevan M.

    2009-01-01

    Phosphoinositide 3-kinases (PI3Ks) are among the most frequently activated signaling pathways in cancer. In chronic lymphocytic leukemia (CLL), signals from the microenvironment are critical for expansion of the malignant B cells, and cause constitutive activation of PI3Ks. CXCR4 is a key receptor for CLL cell migration and adhesion to marrow stromal cells (MSCs). Because of the importance of CXCR4 and PI3Ks for CLL-microenvironment cross-talk, we investigated the activity of novel, isoform-selective PI3K inhibitors that target different isoforms of the p110-kDa subunit. Inhibition with p110α inhibitors (PIK-90 and PI-103) resulted in a significant reduction of chemotaxis and actin polymerization to CXCL12 and reduced migration beneath MSC (pseudoemperipolesis). Western blot and reverse phase protein array analyses consistently demonstrated that PIK-90 and PI-103 inhibited phosphorylation of Akt and S6, whereas p110δ or p110β/p110δ inhibitors were less effective. In suspension and MSC cocultures, PI-103 and PIK-90 were potent inducers of CLL cell apoptosis. Moreover, these p110α inhibitors enhanced the cytotoxicity of fludarabine and reversed the protective effect of MSC on fludarabine-induced apoptosis. Collectively, our data demonstrate that p110α inhibitors antagonize stromal cell-derived migration, survival, and drug-resistance signals and therefore provide a rational to explore the therapeutic activity of these promising agents in CLL. PMID:19318683

  11. Functional specificity of PMCA isoforms?

    PubMed

    Domi, Teuta; Di Leva, Francesca; Fedrizzi, Laura; Rimessi, Alessandro; Brini, Marisa

    2007-03-01

    In mammals, four different genes encode four PMCA isoforms. PMCA1 and PMCA4 are expressed ubiquitously. PMCA2 and PMCA3 are expressed prevalently in the central nervous systems. More than 30 variants are generated by mechanisms of alternative splicing. The physiological meaning of the existence of such elevated number of isoforms is not clear, but it would be plausible to relate it to the cell-specific demands of Ca2+ homeostasis. To characterize functional specificity of PMCA variants we have investigated two aspects: the effects of the overexpression of the different PMCA variants on cellular Ca2+ handling and the existence of possible isoform-specific interactions with partner proteins using a yeast two-hybrid technique. The four basic PMCA isoforms were coexpressed in CHO cells together with the Ca2+-sensitive recombinant photoprotein aequorin. The effects of their overexpression on Ca2+ homeostasis were monitored in the living cells. They had revealed that the ubiquitous isoforms 1 and 4 are less effective in reducing the Ca2+ peaks generated by cell stimulation as compared to the neuron-specific isoforms 2 and 3. To establish whether these differences were related to different and new physiological regulators of the pump, the 90 N-terminal residues of PMCA2 and PMCA4 have been used as baits for the search of molecular partners. Screening of a human brain cDNA library with the PMCA4 bait specified the epsilon-isoform of protein 14-3-3, whereas no 14-3-3 epsilon clone was obtained with the PMCA2 bait. Overexpression of PMCA4/14-3-3 epsilon (but not of PMCA2/14-3-3 epsilon) in HeLa cells together with targeted aequorins showed that the ability of the cells to export Ca2+ was impaired. Thus, the interaction with 14-3-3 epsilon inhibited PMCA4 but not PMCA2. The role of PMCA2 has been further characterized by Ca2+ measurements in cells overexpressing different splicing variants. The results indicated that the combination of alternative splicing at two different

  12. PKC Isoform Expression in Modeled Microgravity

    NASA Technical Reports Server (NTRS)

    Risin, Diana; Sundaresan, Alamelu; Pellis, Neal R.; Dawson, David L. (Technical Monitor)

    1999-01-01

    Our previous studies showed that modeled (MMG) and true (USA Space Shuttle Missions STS-54 and STS-56) microgravity (MG) inhibit human lymphocyte locomotion, Modeled MG also suppressed polyclonal and antigen-specific lymphocyte activation. Activation of PKC by phorbol myristate acetate (PMA) restored the microgravity-inhibited lymphocyte locomotion as well as activation by phytohaemagglutinin (PHA), whereas calcium ionophore (ionomycin) was unable to restore these functions. Based on these results we hypothesized that MG-induced changes in lymphocyte functions are caused by a fundamental defect in signal transduction mechanism. This defect may be localized either at the PKC level or upstream of PKC, most likely, at the cell membrane level. In this study we examined the expression of PKC isoforms alpha, epsilon and delta in PBMC cultured in rotating wall vessel bioreactor, developed at NASA JSC, which models microgravity by sustaining cells in continuous free fall. The assessment of the isoforms was performed by FACS analysis following cell permeabilization. A decrease in the expression of isoforms epsilon and delta, but not isoform a, was observed in PBMC cultured in microgravity conditions. These data suggest that MMG might selectively affect the expression of Ca2+ independent isoforms of PKC Molecular analysis confirm selective suppression of Ca2+ independent isoforms of PKC.

  13. Down-regulation of the mitochondrial aspartate-glutamate carrier isoform 1 AGC1 inhibits proliferation and N-acetylaspartate synthesis in Neuro2A cells.

    PubMed

    Profilo, Emanuela; Peña-Altamira, Luis Emiliano; Corricelli, Mariangela; Castegna, Alessandra; Danese, Alberto; Agrimi, Gennaro; Petralla, Sabrina; Giannuzzi, Giulia; Porcelli, Vito; Sbano, Luigi; Viscomi, Carlo; Massenzio, Francesca; Palmieri, Erika Mariana; Giorgi, Carlotta; Fiermonte, Giuseppe; Virgili, Marco; Palmieri, Luigi; Zeviani, Massimo; Pinton, Paolo; Monti, Barbara; Palmieri, Ferdinando; Lasorsa, Francesco Massimo

    2017-02-21

    The mitochondrial aspartate-glutamate carrier isoform 1 (AGC1) catalyzes a Ca(2+)-stimulated export of aspartate to the cytosol in exchange for glutamate, and is a key component of the malate-aspartate shuttle which transfers NADH reducing equivalents from the cytosol to mitochondria. By sustaining the complete glucose oxidation, AGC1 is thought to be important in providing energy for cells, in particular in the CNS and muscle where this protein is mainly expressed. Defects in the AGC1 gene cause AGC1 deficiency, an infantile encephalopathy with delayed myelination and reduced brain N-acetylaspartate (NAA) levels, the precursor of myelin synthesis in the CNS. Here, we show that undifferentiated Neuro2A cells with down-regulated AGC1 display a significant proliferation deficit associated with reduced mitochondrial respiration, and are unable to synthesize NAA properly. In the presence of high glutamine oxidation, cells with reduced AGC1 restore cell proliferation, although oxidative stress increases and NAA synthesis deficit persists. Our data suggest that the cellular energetic deficit due to AGC1 impairment is associated with inappropriate aspartate levels to support neuronal proliferation when glutamine is not used as metabolic substrate, and we propose that delayed myelination in AGC1 deficiency patients could be attributable, at least in part, to neuronal loss combined with lack of NAA synthesis occurring during the nervous system development.

  14. Carbonic anhydrase inhibitors: in vitro inhibition of α isoforms (hCA I, hCA II, bCA III, hCA IV) by flavonoids.

    PubMed

    Ekinci, Derya; Karagoz, Lutfi; Ekinci, Deniz; Senturk, Murat; Supuran, Claudiu T

    2013-04-01

    A series of flavonoids, such as quercetin, catechin, apigenin, luteolin, morin, were investigated for their inhibitory effects against the metalloenzyme carbonic anhydrase (CA). The compounds were tested against four α-CA isozymes purified from human and bovine (hCA I, hCA II, bCA III, hCA IV) tissues. The four isozymes showed quite diverse inhibition profiles with these compounds. The flavonoids inhibited hCA I with K(I)-s in the range of 2.2-12.8 μM, hCA II with K(I)-s in the range of 0.74-6.2 μM, bCA III with K(I)-s in the range of 2.2-21.3 μM, and hCA IV with inhibition constants in the range of 4.4-15.7, with an esterase assay using 4-nitrophenyl acetate as substrate. Some simple phenols/sulfonamides were also investigated as standard inhibitors. The flavonoids incorporate phenol moieties which inhibit these CAs through a diverse, not yet determined inhibition mechanism, compared to classic inhibitors such as the sulfonamide/sulfamate ones.

  15. Id-1B, an alternatively spliced isoform of the inhibitor of differentiation-1, impairs cancer cell malignancy through inhibition of proliferation and angiogenesis.

    PubMed

    Nguewa, P; Manrique, I; Díaz, R; Redrado, M; Parrondo, R; Perez-Stable, C; Calvo, A

    2014-01-01

    Id-1 is a member of the helix-loop-helix family of proteins that regulates the activity of transcription factors to suppress cellular differentiation and to promote cell growth. Overexpression of Id-1 in tumor cells correlates with increased malignancy and resistance to chemotherapy and radiotherapy. Id-1B is an isoform generated by alternative splicing that differs from the classical Id-1 in the 13-C-terminal amino acids, whose function is at present unknown. We have studied the role of Id-1B in cancer and its expression in healthy/malignant lung tissues. Overexpression of Id-1B in A549 lung and PC3 prostate cancer cells reduced anchorage-dependent and independent proliferation and clonogenic potential. Moreover, it increased the proportion of cells in the G0/G1 phase of the cell cycle and p27 levels, while reduced phospho-Erk and cyclin A levels. Through microarray analysis, we identified genes involved in cell growth and proliferation that are specifically deregulated as a consequence of Id-1B overexpression, including IGF2, BMP4, Id2, GATA3, EREG and AREG. Id-1B overexpressing cells that were treated with 4Gy irradiation dose were significantly less resistant to cell death. In vivo assays demonstrated that tumors with high Id-1B levels exhibited less growth (p<0.01), metabolic activity (glucose uptake) and angiogenesis (p<0.05) compared to tumors with low Id-1B expression; mice survival was significantly extended (p<0.05). Quantification by qRT-PCR revealed that expression of Id-1B was significantly lower (p<0.01) in human lung tumors compared to their matched nonmalignant counterparts. In conclusion, our results demonstrate that Id-1B decreases the malignancy of lung and prostate cancer cells, sensitizes them to radiotherapy-induced cell death, and counteracts the protumorigenic role of the classical form of Id-1.

  16. Spinach pyruvate kinase isoforms: partial purification and regulatory properties

    SciTech Connect

    Baysdorfer, C.; Bassham, J.A.

    1984-02-01

    Pyruvate kinase from spinach (Spinacea oleracea L.) leaves consists of two isoforms, separable by blue agarose chromatography. Both isoforms share similar pH profiles and substrate and alternate nucleotide K/sub m/ values. In addition, both isoforms are inhibited by oxalate and ATP and activated by AMP. The isoforms differ in their response to three key metabolites; citrate, aspartate, and glutamate. The first isoform is similar to previously reported plant pyruvate kinases in its sensitivity to citrate inhibition. The K/sub i/ for this inhibition is 1.2 millimolar citrate. The second isoform is not affected by citrate but is regulated by aspartate and glutamate. Aspartate is an activator with a K/sub a/ of 0.05 millimolar, and glutamate is an inhibitor with a K/sub i/ of 0.68 millimolar. A pyruvate kinase with these properties has not been previously reported. Based on these considerations, the authors suggest that the activity of the first isoform is regulated by respiratory metabolism. The second isoform, in contrast, may be regulated by the demand for carbon skeletons for use in ammonia assimilation.

  17. The sucrose–trehalose 6-phosphate (Tre6P) nexus: specificity and mechanisms of sucrose signalling by Tre6P

    PubMed Central

    Yadav, Umesh Prasad; Ivakov, Alexander; Feil, Regina; Lunn, John Edward

    2014-01-01

    Trehalose 6-phosphate (Tre6P), the intermediate of trehalose biosynthesis, has a profound influence on plant metabolism, growth, and development. It has been proposed that Tre6P acts as a signal of sugar availability and is possibly specific for sucrose status. Short-term sugar-feeding experiments were carried out with carbon-starved Arabidopsis thaliana seedlings grown in axenic shaking liquid cultures. Tre6P increased when seedlings were exogenously supplied with sucrose, or with hexoses that can be metabolized to sucrose, such as glucose and fructose. Conditional correlation analysis and inhibitor experiments indicated that the hexose-induced increase in Tre6P was an indirect response dependent on conversion of the hexose sugars to sucrose. Tre6P content was affected by changes in nitrogen status, but this response was also attributable to parallel changes in sucrose. The sucrose-induced rise in Tre6P was unaffected by cordycepin but almost completely blocked by cycloheximide, indicating that de novo protein synthesis is necessary for the response. There was a strong correlation between Tre6P and sucrose even in lines that constitutively express heterologous trehalose-phosphate synthase or trehalose-phosphate phosphatase, although the Tre6P:sucrose ratio was shifted higher or lower, respectively. It is proposed that the Tre6P:sucrose ratio is a critical parameter for the plant and forms part of a homeostatic mechanism to maintain sucrose levels within a range that is appropriate for the cell type and developmental stage of the plant. PMID:24420566

  18. The sucrose-trehalose 6-phosphate (Tre6P) nexus: specificity and mechanisms of sucrose signalling by Tre6P.

    PubMed

    Yadav, Umesh Prasad; Ivakov, Alexander; Feil, Regina; Duan, Guang You; Walther, Dirk; Giavalisco, Patrick; Piques, Maria; Carillo, Petronia; Hubberten, Hans-Michael; Stitt, Mark; Lunn, John Edward

    2014-03-01

    Trehalose 6-phosphate (Tre6P), the intermediate of trehalose biosynthesis, has a profound influence on plant metabolism, growth, and development. It has been proposed that Tre6P acts as a signal of sugar availability and is possibly specific for sucrose status. Short-term sugar-feeding experiments were carried out with carbon-starved Arabidopsis thaliana seedlings grown in axenic shaking liquid cultures. Tre6P increased when seedlings were exogenously supplied with sucrose, or with hexoses that can be metabolized to sucrose, such as glucose and fructose. Conditional correlation analysis and inhibitor experiments indicated that the hexose-induced increase in Tre6P was an indirect response dependent on conversion of the hexose sugars to sucrose. Tre6P content was affected by changes in nitrogen status, but this response was also attributable to parallel changes in sucrose. The sucrose-induced rise in Tre6P was unaffected by cordycepin but almost completely blocked by cycloheximide, indicating that de novo protein synthesis is necessary for the response. There was a strong correlation between Tre6P and sucrose even in lines that constitutively express heterologous trehalose-phosphate synthase or trehalose-phosphate phosphatase, although the Tre6P:sucrose ratio was shifted higher or lower, respectively. It is proposed that the Tre6P:sucrose ratio is a critical parameter for the plant and forms part of a homeostatic mechanism to maintain sucrose levels within a range that is appropriate for the cell type and developmental stage of the plant.

  19. The function of Drosophila p53 isoforms in apoptosis

    PubMed Central

    Zhang, B; Rotelli, M; Dixon, M; Calvi, B R

    2015-01-01

    The p53 protein is a major mediator of the cellular response to genotoxic stress and is a crucial suppressor of tumor formation. In a variety of organisms, p53 and its paralogs, p63 and p73, each encode multiple protein isoforms through alternative splicing, promoters, and translation start sites. The function of these isoforms in development and disease are still being defined. Here, we evaluate the apoptotic potential of multiple isoforms of the single p53 gene in the genetic model Drosophila melanogaster. Most previous studies have focused on the p53A isoform, but it has been recently shown that a larger p53B isoform can induce apoptosis when overexpressed. It has remained unclear, however, whether one or both isoforms are required for the apoptotic response to genotoxic stress. We show that p53B is a much more potent inducer of apoptosis than p53A when overexpressed. Overexpression of two newly identified short isoforms perturbed development and inhibited the apoptotic response to ionizing radiation. Analysis of physiological protein expression indicated that p53A is the most abundant isoform, and that both p53A and p53B can form a complex and co-localize to sub-nuclear compartments. In contrast to the overexpression results, new isoform-specific loss-of-function mutants indicated that it is the shorter p53A isoform, not full-length p53B, that is the primary mediator of pro-apoptotic gene transcription and apoptosis after ionizing radiation. Together, our data show that it is the shorter p53A isoform that mediates the apoptotic response to DNA damage, and further suggest that p53B and shorter isoforms have specialized functions. PMID:25882045

  20. The Short Isoform of DNAJB6 Protects against 1-Methyl-4-phenylpridinium Ion-Induced Apoptosis in LN18 Cells via Inhibiting Both ROS Formation and Mitochondrial Membrane Potential Loss

    PubMed Central

    Hong, Yeon-Mi; Hong, Yohan; Choi, Yeong-Gon; Jin, Soo Hee; Sung, Backil; Lee, Sook-Hyun; Jung, Hyejin

    2017-01-01

    In a previous study, we found that the short isoform of DNAJB6 (DNAJB6(S)) had been decreased in the striatum of a mouse model of Parkinson's disease (PD) induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). DNAJB6, one of the heat shock proteins, has been implicated in the pathogenesis of PD. In this study, we explored the cytoprotective effect of DNAJB6(S) against 1-methyl-4-phenylpyridinium ion- (MPP+-) induced apoptosis and the underlying molecular mechanisms in cultured LN18 cells from astrocytic tumors. We observed that MPP+ significantly reduced the cell viability and induced apoptosis in LN18 glioblastoma cells. DNAJB6(S) protected LN18 cells against MPP+-induced apoptosis not only by suppressing Bax cleavage but also by inhibiting a series of apoptotic events including loss of mitochondrial membrane potential, increase in intracellular reactive oxygen species, and activation of caspase-9. These observations suggest that the cytoprotective effects of DNAJB6(S) may be mediated, at least in part, by the mitochondrial pathway of apoptosis. PMID:28280525

  1. Carbonic anhydrase inhibitors. Inhibition of human cytosolic isoforms I and II with (reduced) Schiff's bases incorporating sulfonamide, carboxylate and carboxymethyl moieties.

    PubMed

    Nasr, Gihane; Cristian, Alina; Barboiu, Mihail; Vullo, Daniella; Winum, Jean-Yves; Supuran, Claudiu T

    2014-05-15

    A library of Schiff bases was synthesized by condensation of aromatic amines incorporating sulfonamide, carboxylic acid or carboxymethyl functionalities as Zn(2+)-binding groups, with aromatic aldehydes incorporating tert-butyl, hydroxy and/or methoxy groups. The corresponding amines were thereafter obtained by reduction of the imines. These compounds were assayed for the inhibition of two cytosolic human carbonic anhydrase (hCA, EC 4.2.1.1) isoenzymes, hCA I and II. The Ki values of the Schiff bases were in the range of 7.0-21,400nM against hCA II and of 52-8600nM against hCA I, respectively. The corresponding amines showed Ki values in the range of 8.6nM-5.3μM against hCA II, and of 18.7-251nM against hCA I, respectively. Unlike the imines, the reduced Schiff bases are stable to hydrolysis and several low-nanomolar inhibitors were detected, most of them incorporating sulfonamide groups. Some carboxylates also showed interesting CA inhibitory properties. Such hydrosoluble derivatives may show pharmacologic applications.

  2. NMR studies on polyphosphide Ce6Ni6P17

    NASA Astrophysics Data System (ADS)

    Koyama, T.; Yamada, H.; Ueda, K.; Mito, T.; Aoyama, Y.; Nakano, T.; Takeda, N.

    2016-02-01

    We report the result of 31P nuclear magnetic resonance (NMR) studies on Ce6Ni6P17. The observed NMR spectra show a Lorentzian-type and an asymmetric shapes, reflecting the local symmetry around each P site in the cubic unit cell. We have identified the observed NMR lines corresponding to three inequivalent P sites and deduced the temperature dependence of the Knight shift for each site. The Knight shifts increase with decreasing temperature down to 1.5 K, indicating a localized spin system of Ce6Ni6P17. Antiferromagnetic correlation between 4f spins is suggested from the negative sign of the Weiss-temperature.

  3. Inversion of the allosteric response of Escherichia coli glucosamine-6-P deaminase to N-acetylglucosamine 6-P, by single amino acid replacements.

    PubMed

    Cisneros, David A; Montero-Morán, Gabriela M; Lara-González, Samuel; Calcagno, Mario L

    2004-01-01

    Amino acid replacements in the active site of glucosamine-6-P deaminase from Escherichia coli (GlcN6P deaminase, EC 3.5.99.6) involving the residues D141 and E148 produce atypical allosteric kinetics. These residues are located in the chain segment 139-156 which is part of the active site and which also forms several intersubunit contacts close to the allosteric site. In the D141N and E148Q mutant forms of this deaminase, there is an inversion of the effect of its physiological allosteric effector, N-acetylglucosamine 6-P, which becomes an inhibitor at substrate concentrations above a critical value. For both mutants, this particular point appears at low substrate concentration and the inhibition by the allosteric activator is the dominant effect in velocity versus substrate curves. These effects are analyzed as a particular case of the concerted allosteric model, assuming that the R state, the conformer displaying the higher affinity for the substrate, is the less catalytic state, thus producing an inverted allosteric response.

  4. Inhibition of aryl hydrocarbon receptor transactivation and DNA adduct formation by CYP1 isoform-selective metabolic deactivation of benzo[a]pyrene

    SciTech Connect

    Endo, Kaori; Uno, Shigeyuki; Seki, Taiichiro; Ariga, Toyohiko; Kusumi, Yoshiaki; Mitsumata, Masako; Yamada, Sachiko; Makishima, Makoto

    2008-07-15

    Benzo[a]pyrene (BaP), a polyaromatic hydrocarbon produced by the combustion of cigarettes and coke ovens, is a known procarcinogen. BaP activates the aryl hydrocarbon receptor (AhR) and induces the expression of a battery of genes, including CYP1A1, which metabolize BaP to toxic compounds. The possible role of CYP1 enzymes in mediating BaP detoxification or metabolic activation remains to be elucidated. In this study, we assessed the effects of CYP1 enzymes (CYP1A1, CYP1A2 and CYP1B1) on BaP-induced AhR transactivation and DNA adduct formation in HEK293 cells and HepG2 cells. Transfection of CYP1A1 and CYP1B1, but not CYP1A2, suppressed BaP-induced activation of AhR. Expression of CYP1A1 and CYP1A2, but not CYP1B1, inhibited DNA adduct formation in BaP-treated HepG2 cells. These results indicate that CYP1A1 and CYP1B1 play a role in deactivation of BaP on AhR and that CYP1A1 and CYP1A2 are involved in BaP detoxification by suppressing DNA adduct formation. BaP treatment did not induce DNA adduct formation in HEK293 cells, even after transfection of CYP1 enzymes, suggesting that expression of CYP1 enzymes is not sufficient for DNA adduct formation. Lower expression of epoxide hydrolase and higher expression of glutathione S-transferase P1 (GSTP1) and GSTM1/M2 were observed in HEK293 cells compared with HepG2 cells. Dynamic expression of CYP1A1, CYP1A2 and CYP1B1 along with expression of other enzymes such as epoxide hydrolase and phase II enzymes may determine the detoxification or metabolic activation of BaP.

  5. Lot6p from Saccharomyces cerevisiae is a FMN-dependent reductase with a potential role in quinone detoxification.

    PubMed

    Sollner, Sonja; Nebauer, Ruth; Ehammer, Heidemarie; Prem, Anna; Deller, Sigrid; Palfey, Bruce A; Daum, Günther; Macheroux, Peter

    2007-03-01

    NAD(P)H:quinone acceptor oxidoreductases are flavoenzymes expressed in the cytoplasm of many tissues and afford protection against the cytotoxic effects of electrophilic quinones by catalyzing a strict two-electron reduction. Such enzymes have been reported from several mammalian sources, e.g. human, mouse and rat, and from plant species. Here, we report identification of Lot6p (YLR011wp), the first soluble quinone reductase from the unicellular model organism Saccharomyces cerevisiae. Localization studies using an antibody raised against Lot6p as well as microscopic inspection of Lot6p-GFP demonstrated accumulation of the enzyme in the cytosol of yeast cells. Despite sharing only 23% similarity to type 1 human quinone reductase, Lot6p possesses biochemical properties that are similar to its human counterpart. The enzyme catalyzes a two-electron reduction of a series of natural and artificial quinone substrates at the expense of either NADH or NADPH. The kinetic mechanism follows a ping-pong bi-bi reaction scheme, with K(M) values of 1.6-11 microm for various quinones. Dicoumarol and Cibacron Marine, two well-known inhibitors of the quinone reductase family, bind to Lot6p and inhibit its activity. In vivo experiments demonstrate that the enzymatic activity of Lot6p is consistent with the phenotype of both Deltalot6 and Lot6p overexpressing strains, suggesting that Lot6p may play a role in managing oxidative stress in yeast.

  6. DNA signals at isoform promoters

    PubMed Central

    Dai, Zhiming; Xiong, Yuanyan; Dai, Xianhua

    2016-01-01

    Transcriptional heterogeneity is extensive in the genome, and most genes express variable transcript isoforms. However, whether variable transcript isoforms of one gene are regulated by common promoter elements remain to be elucidated. Here, we investigated whether isoform promoters of one gene have separated DNA signals for transcription and translation initiation. We found that TATA box and nucleosome-disfavored DNA sequences are prevalent in distinct transcript isoform promoters of one gene. These DNA signals are conserved among species. Transcript isoform has a RNA-determined unstructured region around its start site. We found that these DNA/RNA features facilitate isoform transcription and translation. These results suggest a DNA-encoded mechanism by which transcript isoform is generated. PMID:27353836

  7. CASC15-S is a tumor suppressor lncRNA at the 6p22 neuroblastoma susceptibility locus

    PubMed Central

    Russell, Mike R.; Penikis, Annalise; Oldridge, Derek A.; Alvarez-Dominguez, Juan R.; McDaniel, Lee; Diamond, Maura; Padovan, Olivia; Raman, Pichai; Li, Yimei; Wei, Jun S.; Zhang, Shile; Gnanchandran, Janahan; Seeger, Robert; Asgharzadeh, Shahab; Khan, Javed; Diskin, Sharon J.; Maris, John M.; Cole, Kristina A.

    2015-01-01

    Chromosome 6p22 was identified recently as a neuroblastoma susceptibility locus, but its mechanistic contributions to tumorigenesis are as yet undefined. Here we report that the most highly significant single nucleotide polymorphism (SNP) associations reside within CASC15, a long non-coding RNA that we define as a tumor suppressor at 6p22. Low-level expression of a short CASC15 isoform (CASC15-S) associated highly with advanced neuroblastoma and poor patient survival. In human neuroblastoma cells, attenuating CASC15-S increased cellular growth and migratory capacity. Gene expression analysis revealed downregulation of neuroblastoma-specific markers in cells with attenuated CASC15-S, with concomitant increases in cell adhesion and extracellular matrix transcripts. Altogether, our results point to CASC15-S as a mediator of neural growth and differentiation, which impacts neuroblastoma initiation and progression. PMID:26100672

  8. Survivin isoform Delta Ex3 regulates tumor spheroid formation.

    PubMed

    Espinosa, Magali; Ceballos-Cancino, Gisela; Callaghan, Richard; Maldonado, Vilma; Patiño, Nelly; Ruíz, Víctor; Meléndez-Zajgla, Jorge

    2012-05-01

    Survivin is an important member of the Inhibitor of Apoptosis Proteins (IAPs) family and has essential roles in apoptosis and cell cycle progression. This gene is commonly upregulated in human cancer and provides an exciting diagnostic and therapeutic target. Survivin is expressed as several isoforms that are generated by alternative splicing, and some of these present antagonistic activities. Currently, information regarding the regulation of these isoforms is lacking. In this study, we sought to analyze survivin Delta Ex3 expression in a three-dimensional model of avascular tumors and its overexpression effects in processes such as proliferation, clonogenicity and apoptosis. We found a positive correlation between spheroid growth and survivin Delta Ex3 expression during the exponential phase. We demonstrated that this isoform not only decreased apoptosis but also inhibited tumor spheroid formation by decreasing proliferation and clonogenic survival. These results point toward a dual and antagonistic effect of this spliced survivin isoform in cancer development.

  9. Differential activities of glucocorticoid-induced leucine zipper protein isoforms.

    PubMed

    Soundararajan, Rama; Wang, Jian; Melters, Daniël; Pearce, David

    2007-12-14

    Glucocorticoid-induced leucine zipper protein (GILZ) is expressed in both epithelial and immune tissues and modulates a variety of cellular functions, including proliferation and epithelial sodium channel (ENaC) activity. A number of reports have described various GILZ activities, focusing on a single isoform with molecular mass of approximately 17 kDa, now termed GILZ1. In GILZ immunoblots using a newly developed antiserum, we detected multiple species in extracts from cultured kidney cells. Mass spectrometric analysis revealed that one of these represented a previously uncharacterized distinct isoform of GILZ, GILZ2. Rapid amplification of cDNA ends was used to clone cDNAs corresponding to four isoforms, which, in addition to GILZ1 and GILZ2, included new isoforms GILZ3 and GILZ4. Heterologous expression of these four GILZ isoforms in cultured cells revealed striking functional differences. Notably, GILZ1 was the only isoform that significantly stimulated ENaC-mediated Na+ current in a kidney collecting duct cell line, although GILZ2 and GILZ3 also stimulated ENaC surface expression in HEK 293 cells. GILZ1 and GILZ3, and to a lesser extent GILZ2, inhibited ERK phosphorylation. Interestingly, GILZ4, which had no effect on either ENaC or ERK, potently suppressed cellular proliferation, as did GILZ1, but not GILZ2 or GILZ3. Finally, rat and mouse tissues all expressed multiple GILZ species but varied in the relative abundance of each. These data suggest that multiple GILZ isoforms are expressed in most cells and tissues and that these play distinct roles in regulating key cellular functions, including proliferation and ion transport. Furthermore, GILZ inhibition of ERK appears to play an essential role in stimulation of cell surface ENaC but not in inhibition of proliferation.

  10. Akt isoform specific effects in ovarian cancer progression

    PubMed Central

    Linnerth-Petrik, Nicolle M.; Santry, Lisa A.; Moorehead, Roger; Jücker, Manfred

    2016-01-01

    Ovarian cancer remains a significant therapeutic problem and novel, effective therapies are needed. Akt is a serine-threonine kinase that is overexpressed in numerous cancers, including ovarian. Mammalian cells express three Akt isoforms which are encoded by distinct genes. Although there are several Akt inhibitors in clinical trials, most indiscriminately target all isoforms. Current in vitro data and animal knockout experiments suggest that the Akt isoforms may have divergent roles. In this paper, we determined the isoform-specific functions of Akt in ovarian cancer cell proliferation in vitro and in ovarian cancer progression in vivo. For in vitro experiments, murine and human ovarian cancer cells were treated with Akt inhibitors and cell viability was assessed. We used two different in vivo approaches to identify the roles of Akt isoforms in ovarian cancer progression and their influence on the primary tumor and tumor microenvironment. In one experiment, wild-type C57Bl6 mice were orthotopically injected with ID8 cells with stable knockdown of Akt isoforms. In a separate experiment, mice null for Akt 1-3 were orthotopically injected with WT ID8 cells (Figure 1). Our data show that inhibition of Akt1 significantly reduced ovarian cancer cell proliferation and inhibited tumor progression in vivo. Conversely, disruption of Akt2 increased tumor growth. Inhibition of Akt3 had an intermediate phenotype, but also increased growth of ovarian cancer cells. These data suggest that there is minimal redundancy between the Akt isoforms in ovarian cancer progression. These findings have important implications in the design of Akt inhibitors for the effective treatment of ovarian cancer. PMID:27533079

  11. Isoform-targeted regulation of cardiac adenylyl cyclase.

    PubMed

    Ishikawa, Yoshihiro

    2003-01-01

    Numerous attempts have been made to develop strategies for regulating the intracellular cyclic AMP signal pharmacologically, with an intention to establish either new medical therapeutic methods or experimental tools. In the past decades, many pharmacological reagents have been identified that regulate this pathway at the level of the receptor. G protein, adenylyl cyclase, cyclic AMP, protein kinase A and phosphodiesterase. Since the cloning of adenylyl cyclase isoforms during the 1990s, investigators including ourselves have tried to find reagents that regulate the activity of this enzyme directly in an isoform-dependent manner. The ultimate goal of developing such reagents would be to regulate the cyclic AMP signal in an organ-dependent manner. Ourselves and other workers have reported that such reagents may vary from a simple cation to kinases. In a more recent study, using the results from crystallographic studies and computer-assisted drug design programs, we have identified subtype-selective regulators of adenylyl cyclase. Such regulators are mostly based upon forskolin, a diterpene compound obtained from Coleus forskolii, that acts directly on adenylyl cyclase to increase the intracellular levels of cyclic AMP. Similarly, novel reagents have been identified that inhibit a specific adenylyl cyclase isoform (e.g. type 5 adenylyl cyclase). Such reagents would potentially provide a new therapeutic strategy to treat hypertension, for example, as well as methods to selectively stimulate or inhibit this adenylyl cyclase isoform, which may be reminiscent of overexpression or knocking out of the cardiac adenylyl cyclase isoform by the use of a pharmacological method.

  12. Chemical origins of isoform selectivity in histone deacetylase inhibitors.

    PubMed

    Butler, Kyle V; Kozikowski, Alan P

    2008-01-01

    Histones undergo extensive posttranslational modifications that affect gene expression. Acetylation is a key histone modification that is primarily regulated by two enzymes, one of which is histone deacetylase (HDAC). The activity of HDAC causes transcriptional silencing of DNA. Eleven distinct zinc-dependent histone deacetylase isoforms have been identified in humans. Each isoform has a unique structure and function, and regulates a unique set of genes. HDAC is responsible for the regulation of many genes involved in cancer cell proliferation, and it has been implicated in the pathogenesis of many neurological conditions. HDAC inhibitors are known to be very effective anti-cancer agents, and research has shown them to be potential treatments for many other conditions. Histone deacetylase inhibitors modify the expression of many genes, and it is possible that inhibition of one isoform could cause epigenetic changes that are beneficial to treatment of a disease, while inhibition of another isoform could cause contradictory changes. Selective HDAC inhibitors will be better able to avoid these types of situations than non-specific inhibitors, and may also be less toxic than pan-HDAC inhibitors. Many potent pan-HDAC inhibitors have already been developed, leaving the development of selective inhibitors at the forefront of HDAC drug development. Certain structural moieties may be added to HDAC inhibitors to give isoform selectivity, and these will be discussed in this review. This review will focus on the applications of selective HDAC inhibitors, inhibitors reported to show selectivity, and the relationship between inhibitor structure and selectivity.

  13. Akt isoforms in vascular disease

    PubMed Central

    Yu, Haixiang; Littlewood, Trevor; Bennett, Martin

    2015-01-01

    The mammalian serine/threonine Akt kinases comprise three closely related isoforms: Akt1, Akt2 and Akt3. Akt activation has been implicated in both normal and disease processes, including in development and metabolism, as well as cancer and cardiovascular disease. Although Akt signalling has been identified as a promising therapeutic target in cancer, its role in cardiovascular disease is less clear. Importantly, accumulating evidence suggests that the three Akt isoforms exhibit distinct tissue expression profiles, localise to different subcellular compartments, and have unique modes of activation. Consistent with in vitro findings, genetic studies in mice show distinct effects of individual Akt isoforms on the pathophysiology of cardiovascular disease. This review summarises recent studies of individual Akt isoforms in atherosclerosis, vascular remodelling and aneurysm formation, to provide a comprehensive overview of Akt function in vascular disease. PMID:25929188

  14. One isoform of Arg/Abl2 tyrosine kinase is nuclear and the other seven cytosolic isoforms differently modulate cell morphology, motility and the cytoskeleton

    SciTech Connect

    Bianchi, Cristina; Torsello, Barbara; Di Stefano, Vitalba; Zipeto, Maria A.; Facchetti, Rita; Bombelli, Silvia; Perego, Roberto A.

    2013-08-01

    The non-receptor tyrosine kinase Abelson related gene (Arg/Abl2) regulates cell migration and morphogenesis by modulating the cytoskeleton. Arg promotes actin-based cell protrusions and spreading, and inhibits cell migration by attenuating stress fiber formation and contractility via activation of the RhoA inhibitor, p190RhoGAP, and by regulating focal adhesion dynamics also via CrkII phosphorylation. Eight full-length Arg isoforms with different N- and C-termini are endogenously expressed in human cells. In this paper, the eight Arg isoforms, subcloned in the pFLAG-CMV2 vector, were transfected in COS-7 cells in order to study their subcellular distribution and role in cell morphology, migration and cytoskeletal modulation. The transfected 1BSCTS Arg isoform has a nuclear distribution and phosphorylates CrkII in the nucleus, whilst the other isoforms are detected in the cytoplasm. The 1BLCTL, 1BSCTL, 1ASCTS isoforms were able to significantly decrease stress fibers, induce cell shrinkage and filopodia-like protrusions with a significant increase in p190RhoGAP phosphorylation. In contrast, 1ALCTL, 1ALCTS, 1ASCTL and 1BLCTS isoforms do not significantly decrease stress fibers and induce the formation of retraction tail-like protrusions. The 1BLCTL and 1ALCTL isoforms have different effects on cell migration and focal adhesions. All these data may open new perspectives to study the mechanisms of cell invasiveness. -Highlights: • Each of the eight Arg isoforms was transfected in COS-7 cells. • Only the 1BSCTS Arg isoform has a nuclear distribution in transfected cells. • The cytoplasmic isoforms and F-actin colocalize cortically and in cell protrusions. • Arg isoforms differently phosphorylate p190RhoGAP and CrkII. • Arg isoforms differently modulate stress fibers, cell protrusions and motility.

  15. Isoform-specific regulation of adenylyl cyclase: a potential target in future pharmacotherapy.

    PubMed

    Iwatsubo, Kousaku; Tsunematsu, Takashi; Ishikawa, Yoshihiro

    2003-06-01

    Adenylyl cyclase (AC) is a target enzyme of multiple G-protein-coupled receptors (GPCRs). In the past decade, the cloning, structure and biochemical properties of nine AC isoforms were reported, and each isoform of AC shows distinct patterns of tissue distribution and biochemical/pharmacological properties. In addition to the conventional regulators of this enzyme, such as calmodulin (CaM) or PKC, novel regulators, for example, caveolin, have been identified. Most importantly, these regulators work on AC in an isoform dependent manner. Recent studies have demonstrated that certain classic AC inhibitors, i.e., P-site inhibitors, show an isoform-dependent inhibition of AC. The side chain modifications of forskolin, a diterpene extract from Coleus forskolii, markedly enhance its isoform selectivity. When taken together, these findings suggest that it is feasible to develop new pharmacotherapeutic agents that target AC isoforms to regulate various neurohormonal signals in a highly tissue-/organ-specific manner.

  16. ICAM-1: isoforms and phenotypes.

    PubMed

    Ramos, Theresa N; Bullard, Daniel C; Barnum, Scott R

    2014-05-15

    ICAM-1 plays an important role in leukocyte trafficking, immunological synapse formation, and numerous cellular immune responses. Although considered a single glycoprotein, there are multiple membrane-bound and soluble ICAM-1 isoforms that arise from alternative splicing and proteolytic cleavage during inflammatory responses. The function and expression of these isoforms on various cell types are poorly understood. In the generation of ICAM-1-deficient mice, two isoform-deficient ICAM-1 mutants were inadvertently produced as a result of alternative splicing. These mice, along with true ICAM-1-deficient mice and newly generated ICAM-1-transgenic mice, have provided the opportunity to begin examining the role of ICAM-1 isoforms (singly or in combination) in various disease settings. In this review, we highlight the sharply contrasting disease phenotypes using ICAM-1 isoform mutant mice. These studies demonstrate that ICAM-1 immunobiology is highly complex but that individual isoforms, aside from the full-length molecule, make significant contributions to disease development and pathogenesis.

  17. ICAM-1: Isoforms and Phenotypes

    PubMed Central

    Ramos, Theresa N.; Bullard, Daniel C.; Barnum, Scott R.

    2014-01-01

    Intercellular adhesion molecule-1 (ICAM-1) plays an important role in leukocyte trafficking, immunological synapse formation and, numerous cellular immune responses. Although considered a single glycoprotein, there are multiple membrane bound and soluble ICAM-1 isoforms which arise from alternative splicing and proteolytic cleavage during inflammatory responses. The function and expression of these isoforms on various cell types is poorly understood. In the generation of ICAM-1-deficient mice, two isoform-deficient ICAM-1 mutants were inadvertently produced due to alternative splicing. These mice along with true ICAM-1-deficient mice and newly generated ICAM-1 transgenic mice have provided the opportunity to begin examining the role of ICAM-1 isoforms (singly or in combination) in various disease settings. In this review we highlight the sharply contrasting disease phenotypes using ICAM-1 isoform mutant mice. These studies demonstrate that ICAM-1 immunobiology is highly complex but that individual isoforms, aside from the full-length molecule, make significant contributions to disease development and pathogenesis. PMID:24795464

  18. Trehalose-6-P synthase is dispensable for growth on glucose but not for spore germination in Schizosaccharomyces pombe.

    PubMed Central

    Blázquez, M A; Stucka, R; Feldmann, H; Gancedo, C

    1994-01-01

    Trehalose-6-P inhibits hexokinases in Saccharomyces cerevisiae (M. A. Blázquez, R. Lagunas, C. Gancedo, and J. M. Gancedo, FEBS Lett. 329:51-54, 1993), and disruption of the TPS1 gene (formerly named CIF1 or FDP1) encoding trehalose-6-P synthase prevents growth in glucose. We have found that the hexokinase from Schizosaccharomyces pombe is not inhibited by trehalose-6-P even at a concentration of 3 mM. The highest internal concentration of trehalose-6-P that we measured in S. pombe was 0.75 mM after heat shock. We have isolated from S. pombe the tps1+ gene, which is homologous to the Saccharomyces cerevisiae TPS1 gene. The DNA sequence from tps1+ predicts a protein of 479 amino acids with 65% identity with the protein of S. cerevisiae. The tps1+ gene expressed from its own promoter could complement the lack of trehalose-6-P synthase in S. cerevisiae tps1 mutants. The TPS1 gene from S. cerevisiae could also restore trehalose synthesis in S. pombe tps1 mutants. A chromosomal disruption of the tps1+ gene in S. pombe did not have a noticeable effect on growth in glucose, in contrast with the disruption of TPS1 in S. cerevisiae. However, the disruption prevented germination of spores carrying it. The level of an RNA hybridizing with an internal probe of the tps1+ gene reached a maximum after 20 min of heat shock treatment. The results presented support the idea that trehalose-6-P plays a role in the control of glycolysis in S. cerevisiae but not in S. pombe and show that the trehalose pathway has different roles in the two yeast species. Images PMID:8021171

  19. Pharmacological targeting of PI3K isoforms as a therapeutic strategy in chronic lymphocytic leukaemia

    PubMed Central

    Blunt, Matthew D.; Steele, Andrew J.

    2015-01-01

    PI3Kδ inhibitors such as idelalisib are providing improved therapeutic options for the treatment of chronic lymphocytic leukaemia (CLL). However under certain conditions, inhibition of a single PI3K isoform can be compensated by the other PI3K isoforms, therefore PI3K inhibitors which target multiple PI3K isoforms may provide greater efficacy. The development of compounds targeting multiple PI3K isoforms (α, β, δ, and γ) in CLL cells, in vitro, resulted in sustained inhibition of BCR signalling but with enhanced cytotoxicity and the potential for improve clinical responses. This review summarises the progress of PI3K inhibitor development and describes the rationale and potential for targeting multiple PI3K isoforms. PMID:26500849

  20. Vitamin E isoforms as modulators of lung inflammation.

    PubMed

    Abdala-Valencia, Hiam; Berdnikovs, Sergejs; Cook-Mills, Joan M

    2013-10-31

    Asthma and allergic diseases are complex conditions caused by a combination of genetic and environmental factors. Clinical studies suggest a number of protective dietary factors for asthma, including vitamin E. However, studies of vitamin E in allergy commonly result in seemingly conflicting outcomes. Recent work indicates that allergic inflammation is inhibited by supplementation with the purified natural vitamin E isoform α-tocopherol but elevated by the isoform γ-tocopherol when administered at physiological tissue concentrations. In this review, we discuss opposing regulatory effects of α-tocopherol and γ-tocopherol on allergic lung inflammation in clinical trials and in animal studies. A better understanding of the differential regulation of inflammation by isoforms of vitamin E provides a basis towards the design of clinical studies and diets that would effectively modulate inflammatory pathways in lung disease.

  1. Histamine H3-receptor isoforms.

    PubMed

    Bakker, R A

    2004-10-01

    Increasing evidence supports a role for HA as a neurotransmitter and neuromodulator in various brain functions, including emotion, cognition, and feeding. The recent cloning of the histamine H3 receptor allowed for the subsequent cloning of a variety of H3 receptor isoforms from different species as well as the H4 receptor. As a result a wide variety of H3-receptor isoforms are now known that display differential brain expression patterns and signalling properties. These recent discoveries are discussed in view of the growing interest of the H3 receptor as a target for the development of potential therapeutics.

  2. The C-Terminal Domain of Nrf1 Negatively Regulates the Full-Length CNC-bZIP Factor and Its Shorter Isoform LCR-F1/Nrf1β; Both Are Also Inhibited by the Small Dominant-Negative Nrf1γ/δ Isoforms that Down-Regulate ARE-Battery Gene Expression

    PubMed Central

    Zhang, Yiguo; Qiu, Lu; Li, Shaojun; Xiang, Yuancai; Chen, Jiayu; Ren, Yonggang

    2014-01-01

    The C-terminal domain (CTD, aa 686–741) of nuclear factor-erythroid 2 p45-related factor 1 (Nrf1) shares 53% amino acid sequence identity with the equivalent Neh3 domain of Nrf2, a homologous transcription factor. The Neh3 positively regulates Nrf2, but whether the Neh3-like (Neh3L) CTD of Nrf1 has a similar role in regulating Nrf1-target gene expression is unknown. Herein, we report that CTD negatively regulates the full-length Nrf1 (i.e. 120-kDa glycoprotein and 95-kDa deglycoprotein) and its shorter isoform LCR-F1/Nrf1β (55-kDa). Attachment of its CTD-adjoining 112-aa to the C-terminus of Nrf2 yields the chimaeric Nrf2-C112Nrf1 factor with a markedly decreased activity. Live-cell imaging of GFP-CTD reveals that the extra-nuclear portion of the fusion protein is allowed to associate with the endoplasmic reticulum (ER) membrane through the amphipathic Neh3L region of Nrf1 and its basic c-tail. Thus removal of either the entire CTD or the essential Neh3L portion within CTD from Nrf1, LCR-F1/Nrf1β and Nrf2-C112Nrf1, results in an increase in their transcriptional ability to regulate antioxidant response element (ARE)-driven reporter genes. Further examinations unravel that two smaller isoforms, 36-kDa Nrf1γ and 25-kDa Nrf1δ, act as dominant-negative inhibitors to compete against Nrf1, LCR-F1/Nrf1β and Nrf2. Relative to Nrf1, LCR-F1/Nrf1β is a weak activator, that is positively regulated by its Asn/Ser/Thr-rich (NST) domain and acidic domain 2 (AD2). Like AD1 of Nrf1, both AD2 and NST domain of LCR-F1/Nrf1β fused within two different chimaeric contexts to yield Gal4D:Nrf1β607 and Nrf1β:C270Nrf2, positively regulate their transactivation activity of cognate Gal4- and Nrf2-target reporter genes. More importantly, differential expression of endogenous ARE-battery genes is attributable to up-regulation by Nrf1 and LCR-F1/Nrf1β and down-regulation by Nrf1γ and Nrf1δ. PMID:25290918

  3. The C-terminal domain of Nrf1 negatively regulates the full-length CNC-bZIP factor and its shorter isoform LCR-F1/Nrf1β; both are also inhibited by the small dominant-negative Nrf1γ/δ isoforms that down-regulate ARE-battery gene expression.

    PubMed

    Zhang, Yiguo; Qiu, Lu; Li, Shaojun; Xiang, Yuancai; Chen, Jiayu; Ren, Yonggang

    2014-01-01

    The C-terminal domain (CTD, aa 686-741) of nuclear factor-erythroid 2 p45-related factor 1 (Nrf1) shares 53% amino acid sequence identity with the equivalent Neh3 domain of Nrf2, a homologous transcription factor. The Neh3 positively regulates Nrf2, but whether the Neh3-like (Neh3L) CTD of Nrf1 has a similar role in regulating Nrf1-target gene expression is unknown. Herein, we report that CTD negatively regulates the full-length Nrf1 (i.e. 120-kDa glycoprotein and 95-kDa deglycoprotein) and its shorter isoform LCR-F1/Nrf1β (55-kDa). Attachment of its CTD-adjoining 112-aa to the C-terminus of Nrf2 yields the chimaeric Nrf2-C112Nrf1 factor with a markedly decreased activity. Live-cell imaging of GFP-CTD reveals that the extra-nuclear portion of the fusion protein is allowed to associate with the endoplasmic reticulum (ER) membrane through the amphipathic Neh3L region of Nrf1 and its basic c-tail. Thus removal of either the entire CTD or the essential Neh3L portion within CTD from Nrf1, LCR-F1/Nrf1β and Nrf2-C112Nrf1, results in an increase in their transcriptional ability to regulate antioxidant response element (ARE)-driven reporter genes. Further examinations unravel that two smaller isoforms, 36-kDa Nrf1γ and 25-kDa Nrf1δ, act as dominant-negative inhibitors to compete against Nrf1, LCR-F1/Nrf1β and Nrf2. Relative to Nrf1, LCR-F1/Nrf1β is a weak activator, that is positively regulated by its Asn/Ser/Thr-rich (NST) domain and acidic domain 2 (AD2). Like AD1 of Nrf1, both AD2 and NST domain of LCR-F1/Nrf1β fused within two different chimaeric contexts to yield Gal4D:Nrf1β607 and Nrf1β:C270Nrf2, positively regulate their transactivation activity of cognate Gal4- and Nrf2-target reporter genes. More importantly, differential expression of endogenous ARE-battery genes is attributable to up-regulation by Nrf1 and LCR-F1/Nrf1β and down-regulation by Nrf1γ and Nrf1δ.

  4. Facilitation or inhibition of the oestradiol-induced gonadotrophin surge in the immature female rat by progesterone: effects on pituitary responsiveness to gonadotrophin-releasing hormone (GnRH), GnRH self-priming and pituitary mRNAs for the progesterone receptor A and B isoforms.

    PubMed

    Attardi, B; Scott, R; Pfaff, D; Fink, G

    2007-12-01

    Progesterone can either facilitate or inhibit the oestradiol (E(2))-induced gonadotrophin surge. We have previously developed immature female rat models to characterise and investigate the mechanisms of progesterone inhibition or facilitation. The aim of the present study was to determine the role of pituitary responsiveness to gonadotrophin-releasing hormone (GnRH) and GnRH self-priming under conditions of progesterone-facilitation and progesterone-inhibition, and whether the underlying mechanisms reflect changes in mRNAs encoding the A and B isoforms of the progesterone receptor (PR) in the pituitary gland. Pituitary responsiveness to GnRH, determined by measuring the luteinising hormone (LH) response to one i.v. injection of GnRH, was decreased by 60-80% (P < 0.001) in the progesterone-inhibition model. GnRH self-priming, estimated as the increment in the LH response to the second of two injections of GnRH separated by 60 min, was also significantly reduced (P < 0.05) in this model. In the progesterone-facilitation model, the LH response to GnRH injection was increased 2.5-3-fold (P < 0.05), an effect suppressed by the progesterone receptor antagonist, mifepristone. Progesterone-facilitation of LH release and increased pituitary responsiveness to GnRH were blocked by sheep anti-GnRH serum injected i.v. immediately after insertion of progesterone implants. The PR-B mRNA isoform, measured by solution hybridisation/RNase protection assay, was the predominant form in the pituitary of the immature female rat. PR-B was increased by E(2) and decreased by progesterone in both models. Thus, in immature female rats, progesterone-inhibition of the E(2)-induced LH surge is due to significant reduction in pituitary responsiveness to GnRH as well as in the magnitude of GnRH self-priming. Progesterone-facilitation of the E(2)-induced LH surge is due to increased pituitary responsiveness to GnRH, which is mediated by PR, and depends on endogenous GnRH release. The differences

  5. P120-catenin isoforms 1A and 3A differently affect invasion and proliferation of lung cancer cells

    SciTech Connect

    Liu Yang; Dong Qianze; Zhao Yue; Dong Xinjun; Miao Yuan; Dai Shundong; Yang Zhiqiang; Zhang Di; Wang Yan; Li Qingchang; Zhao Chen; Wang Enhua

    2009-03-10

    Different isoforms of p120-catenin (p120ctn), a member of the Armadillo gene family, are variably expressed in different tissues as a result of alternative splicing and the use of multiple translation initiation codons. When expressed in cancer cells, these isoforms may confer different properties with respect to cell adhesion and invasion. We have previously reported that the p120ctn isoforms 1 and 3 were the most highly expressed isoforms in normal lung tissues, and their expression level was reduced in lung tumor cells. To precisely define their biological roles, we transfected p120ctn isoforms 1A and 3A into the lung cancer cell lines A549 and NCI-H460. Enhanced expression of p120ctn isoform 1A not only upregulated E-cadherin and {beta}-catenin, but also downregulated the Rac1 activity, and as a result, inhibited the ability of cells to invade. In contrast, overexpression of p120ctn isoform 3A led to the inactivation of Cdc42 and the activation of RhoA, and had a smaller influence on invasion. However, we found that isoform 3A had a greater ability than isoform 1A in both inhibiting the cell cycle and reducing tumor cell proliferation. The present study revealed that p120ctn isoforms 1A and 3A differently regulated the adhesive, proliferative, and invasive properties of lung cancer cells through distinct mechanisms.

  6. 6p22.3 amplification as a biomarker and potential therapeutic target of advanced stage bladder cancer

    PubMed Central

    Zhang, Jianmin; Underwood, Willie; Yang, Nuo; Frangou, Costa; Eng, Kevin; Head, Karen; Bollag, Roni J.; Kavuri, Sravan K.; Rojiani, Amyn M.; Li, Yingwei; Yan, Li; Hill, Annette; Woloszynska-Read, Anna; Wang, Jianmin; Liu, Song; Trump, Donald L.; Candace, Johnson S.

    2013-01-01

    Genetic and epigenetic alterations have been identified as to contribute directly or indirectly to the generation of transitional cell carcinoma of the urinary bladder (TCC-UB). In a comparative fashion much less is known about copy number alterations in TCC-UB, but it appears that amplification of chromosome 6p22 is one of the most frequent changes. Using fluorescence in situ hybridization (FISH) analyses, we evaluated chromosomal 6p22 amplification in a large cohort of bladder cancer patients with complete surgical staging and outcome data. We have also used shRNA knockdown candidate oncogenes in the cell based study. We found that amplification of chromosome 6p22.3 is significantly associated with the muscle-invasive transitional cell carcinoma of the urinary bladder (TCC-UB) (22%) in contrast to superficial TCC-UB (9%) (p=7.2-04). The rate of 6p22.3 amplification in pN>1 patients (32%) is more than twice that in pN0 (16%) patients (p=0.05). Interestingly, we found that 6p22.3 amplification is as twice as high (p=0.0201) in African American (AA) than European American (EA) TCC-UB patients. Moreover, we showed that the expression of some candidate genes (E2F3, CDKAL1 and Sox4) in the 6p22.3 region is highly correlated with the chromosomal amplification. In particular, knockdown of E2F3 inhibits cell proliferation in a 6p22.3-dependent manner, whereas knockdown of CDKAL1 and Sox4 has no effect on cell proliferation. Using gene expression profiling, we further identified some common as well as distinctive subset targets of the E2F3 family members. In summary, our data indicate that E2F3 is a key regulator of cell proliferation in a subset of bladder cancer and the 6p22.3 amplicon is a biomarker of aggressive phenotype in this tumor type. PMID:24231253

  7. Isoform-specific targeting of ROCK proteins in immune cells

    PubMed Central

    Zanin-Zhorov, Alexandra; Flynn, Ryan; Waksal, Samuel D.; Blazar, Bruce R.

    2016-01-01

    ABSTRACT Rho-associated kinase 1 (ROCK1) and ROCK2 are activated by Rho GTPase and control cytoskeleton rearrangement through modulating the phosphorylation of their down-stream effector molecules. Although these 2 isoforms share more than 90% homology within their kinase domain the question of whether ROCK proteins function identically in different cell types is not clear. By using both pharmacological inhibition and genetic knockdown approaches recent studies suggest that the ROCK2 isoform plays an exclusive role in controlling of T-cell plasticity and macrophage polarization. Specifically, selective ROCK2 inhibition shifts the balance between pro-inflammatory and regulatory T-cell subsets via concurrent regulation of STAT3 and STAT5 phosphorylation, respectively. Furthermore, the administration of an orally available selective ROCK2 inhibitor effectively ameliorates clinical manifestations in experimental models of autoimmunity and chronic graft-vs.-host disease (cGVHD). Because ROCK2 inhibition results in the suppression of M2-type macrophages while favoring polarization of M1-type macrophages, ROCK2 inhibition can correct the macrophage imbalance seen during age-related macular degeneration (AMD). In summary, the exclusive role of ROCK2 in immune system modulation argues for the development and testing of isoform-specific ROCK2 inhibitors for the treatment of inflammatory disorders. PMID:27254302

  8. Cell, isoform, and environment factors shape gradients and modulate chemotaxis.

    PubMed

    Chang, S Laura; Cavnar, Stephen P; Takayama, Shuichi; Luker, Gary D; Linderman, Jennifer J

    2015-01-01

    Chemokine gradient formation requires multiple processes that include ligand secretion and diffusion, receptor binding and internalization, and immobilization of ligand to surfaces. To understand how these events dynamically shape gradients and influence ensuing cell chemotaxis, we built a multi-scale hybrid agent-based model linking gradient formation, cell responses, and receptor-level information. The CXCL12/CXCR4/CXCR7 signaling axis is highly implicated in metastasis of many cancers. We model CXCL12 gradient formation as it is impacted by CXCR4 and CXCR7, with particular focus on the three most highly expressed isoforms of CXCL12. We trained and validated our model using data from an in vitro microfluidic source-sink device. Our simulations demonstrate how isoform differences on the molecular level affect gradient formation and cell responses. We determine that ligand properties specific to CXCL12 isoforms (binding to the migration surface and to CXCR4) significantly impact migration and explain differences in in vitro chemotaxis data. We extend our model to analyze CXCL12 gradient formation in a tumor environment and find that short distance, steep gradients characteristic of the CXCL12-γ isoform are effective at driving chemotaxis. We highlight the importance of CXCL12-γ in cancer cell migration: its high effective affinity for both extracellular surface sites and CXCR4 strongly promote CXCR4+ cell migration. CXCL12-γ is also more difficult to inhibit, and we predict that co-inhibition of CXCR4 and CXCR7 is necessary to effectively hinder CXCL12-γ-induced migration. These findings support the growing importance of understanding differences in protein isoforms, and in particular their implications for cancer treatment.

  9. One isoform of Arg/Abl2 tyrosine kinase is nuclear and the other seven cytosolic isoforms differently modulate cell morphology, motility and the cytoskeleton.

    PubMed

    Bianchi, Cristina; Torsello, Barbara; Di Stefano, Vitalba; Zipeto, Maria A; Facchetti, Rita; Bombelli, Silvia; Perego, Roberto A

    2013-08-01

    The non-receptor tyrosine kinase Abelson related gene (Arg/Abl2) regulates cell migration and morphogenesis by modulating the cytoskeleton. Arg promotes actin-based cell protrusions and spreading, and inhibits cell migration by attenuating stress fiber formation and contractility via activation of the RhoA inhibitor, p190RhoGAP, and by regulating focal adhesion dynamics also via CrkII phosphorylation. Eight full-length Arg isoforms with different N- and C-termini are endogenously expressed in human cells. In this paper, the eight Arg isoforms, subcloned in the pFLAG-CMV2 vector, were transfected in COS-7 cells in order to study their subcellular distribution and role in cell morphology, migration and cytoskeletal modulation. The transfected 1BSCTS Arg isoform has a nuclear distribution and phosphorylates CrkII in the nucleus, whilst the other isoforms are detected in the cytoplasm. The 1BLCTL, 1BSCTL, 1ASCTS isoforms were able to significantly decrease stress fibers, induce cell shrinkage and filopodia-like protrusions with a significant increase in p190RhoGAP phosphorylation. In contrast, 1ALCTL, 1ALCTS, 1ASCTL and 1BLCTS isoforms do not significantly decrease stress fibers and induce the formation of retraction tail-like protrusions. The 1BLCTL and 1ALCTL isoforms have different effects on cell migration and focal adhesions. All these data may open new perspectives to study the mechanisms of cell invasiveness.

  10. Differential sensitivity of rat voltage-sensitive sodium channel isoforms to pyrazoline-type insecticides

    SciTech Connect

    Silver, Kristopher S.; Soderlund, David M. . E-mail: dms6@cornell.edu

    2006-07-15

    Pyrazoline-type insecticides are potent inhibitors of insect and mammalian voltage-sensitive sodium channels. In mammals, there are nine sodium channel {alpha} subunit isoforms that have unique distributions and pharmacological properties, but no published data exist that compare the relative sensitivity of these different mammalian sodium channel isoforms to inhibition by pyrazoline-type insecticides. This study employed the Xenopus oocyte expression system to examine the relative sensitivity of rat Na{sub v}1.2a, Na{sub v}1.4, Na{sub v}1.5, and Na{sub v}1.8 sodium channel {alpha} subunit isoforms to the pyrazoline-type insecticides indoxacarb, DCJW, and RH 3421. Additionally, we assessed the effect of coexpression with the rat {beta}1 auxiliary subunit on the sensitivity of the Na{sub v}1.2a and Na{sub v}1.4 isoforms to these compounds. The relative sensitivity of the four sodium channel {alpha} subunits differed for each of the three compounds we examined. With DCJW, the order of sensitivity was Na{sub v}1.4 > Na{sub v}1.2a > Na{sub v}1.5 > Na{sub v}1.8. In contrast, the relative sensitivity of these isoforms to indoxacarb differed from that to DCJW: the Na{sub v}1.8 isoform was most sensitive, the Na{sub v}1.4 isoform was completely insensitive, and the sensitivities of the Na{sub v}1.5 and Na{sub v}1.2a isoforms were intermediate between these two extremes. Moreover, the pattern of sensitivity to RH 3421 among these four isoforms was different from that for either indoxacarb or DCJW: the Na{sub v}1.4 isoform was most sensitive to RH 3421, whereas the sensitivities of the remaining three isoforms were substantially less than that of the Na{sub v}1.4 isoform and were approximately equivalent. The only statistically significant effect of coexpression of either the Na{sub v}1.2a or Na{sub v}1.4 isoforms with the {beta}1 subunit was the modest reduction in the sensitivity of the Na{sub v}1.2a isoform to RH 3421. These results demonstrate that mammalian sodium

  11. Characterization of a novel periodontal ligament-specific periostin isoform.

    PubMed

    Yamada, S; Tauchi, T; Awata, T; Maeda, K; Kajikawa, T; Yanagita, M; Murakami, S

    2014-09-01

    Periostin is a mesenchymal cell marker predominantly expressed in collagen-rich fibrous connective tissues, including heart valves, tendons, perichondrium, periosteum, and periodontal ligament (PDL). Knockdown of periostin expression in mice results in early-onset periodontitis and failure of cardiac healing after acute myocardial infarction, suggesting that periostin is essential for connective tissue homeostasis and regeneration. However, its role(s) in periodontal tissues has not yet been fully defined. In this study, we describe a novel human isoform of periostin (PDL-POSTN). Isoform-specific analysis by reverse-transcription polymerase chain-reaction (RT-PCR) revealed that PDL-POSTN was predominantly expressed in the PDL, with much lower expression in other tissues and organs. A PDL cell line transfected with PDL-POSTN showed enhanced alkaline phosphatase (ALPase) activity and calcified nodule formation, compared with cells transfected with the full-length periostin isoform. A neutralizing antibody against integrin-αv inhibited both ALPase activity and calcified nodule formation in cells transfected with PDL-POSTN. Furthermore, co-immunoprecipitation assays revealed that PDL-POSTN bound to integrin αvβ3 more strongly than the common isoform of periostin, resulting in strong activation of the integrin αvβ3-focal adhesion kinase (FAK) signaling pathway. These results suggest that PDL-POSTN positively regulates cytodifferentiation and mineralization in PDL cells through integrin αvβ3.

  12. A familial complex chromosome translocation resulting in duplication of 6p25.

    PubMed

    Vermeesch, J R; Thoelen, R; Fryns, Jean Pierre

    2004-01-01

    We report on a girl with psychomotor retardation, severe speech developmental delay and mild dysmorphic features. Molecular cytogenetic analysis showed that the patient was carrier of an insertion (6)(p22.5-->22.4) in chromosome 12. Analysis of the chromosomes of the mother revealed the presence of a complex chromosomal rearrangement. In addition to the insertion (6)(p22.5-->22.4) in chromosome 12 and a pericentric inversion in chromosome 12, the 6p subtelomeric region was absent in the mother. This is, to our knowledge, the smallest pure duplication of chromosome 6p as well as the smallest cryptic subtelomeric 6pter deletion thus far reported.

  13. Inference of Isoforms from Short Sequence Reads

    NASA Astrophysics Data System (ADS)

    Feng, Jianxing; Li, Wei; Jiang, Tao

    Due to alternative splicing events in eukaryotic species, the identification of mRNA isoforms (or splicing variants) is a difficult problem. Traditional experimental methods for this purpose are time consuming and cost ineffective. The emerging RNA-Seq technology provides a possible effective method to address this problem. Although the advantages of RNA-Seq over traditional methods in transcriptome analysis have been confirmed by many studies, the inference of isoforms from millions of short sequence reads (e.g., Illumina/Solexa reads) has remained computationally challenging. In this work, we propose a method to calculate the expression levels of isoforms and infer isoforms from short RNA-Seq reads using exon-intron boundary, transcription start site (TSS) and poly-A site (PAS) information. We first formulate the relationship among exons, isoforms, and single-end reads as a convex quadratic program, and then use an efficient algorithm (called IsoInfer) to search for isoforms. IsoInfer can calculate the expression levels of isoforms accurately if all the isoforms are known and infer novel isoforms from scratch. Our experimental tests on known mouse isoforms with both simulated expression levels and reads demonstrate that IsoInfer is able to calculate the expression levels of isoforms with an accuracy comparable to the state-of-the-art statistical method and a 60 times faster speed. Moreover, our tests on both simulated and real reads show that it achieves a good precision and sensitivity in inferring isoforms when given accurate exon-intron boundary, TSS and PAS information, especially for isoforms whose expression levels are significantly high.

  14. Competitive inhibition of phosphoglucose isomerase of apple leaves by sorbitol 6-phosphate.

    PubMed

    Zhou, Rui; Cheng, Lailiang

    2008-06-16

    Apple leaf cytosolic phosphoglucose isomerase (PGI, EC 5.3.1.9) was purified to an apparent homogeneity with a specific activity of 2456 units/mg protein, and chloroplastic PGI was partially purified to a specific activity of 72 units/mg protein to characterize their biochemical properties. These two isoforms showed differential responses to heat treatment; incubation at 50 degrees C for 10 min resulted in a complete loss of the chloroplastic PGI activity, whereas the cytosolic PGI only lost 50% of its activity. Apple cytosolic PGI is a dimeric enzyme with a molecular mass of 66 kDa for each monomer. The activity of both isoforms was strongly inhibited by erythrose 4-phosphate (E4P) with a K(i) of 1.2 and 3.0 microM for the cytosolic PGI and chloroplastic PGI, respectively. Sorbitol 6-phosphate (Sor6P), an intermediate in sorbitol biosynthesis, was found to be a competitive inhibitor for both cytosolic and chloroplastic PGIs with a K(i) of 61 and 40 microM, respectively. PGIs from both spinach and tomato leaves were also inhibited by Sor6P in a similar manner. The possible physiological significance of this finding is discussed.

  15. Dissecting signalling by individual Akt/PKB isoforms, three steps at once.

    PubMed

    Osorio-Fuentealba, Cesar; Klip, Amira

    2015-09-01

    The serine/threonine kinase Akt/PKB (protein kinase B) is key for mammalian cell growth, survival, metabolism and oncogenic transformation. The diverse level and tissue expression of its three isoforms, Akt1/PKBα, Akt2/PKBβ and Akt3/PKBγ, make it daunting to identify isoform-specific actions in vivo and even in isolated tissues/cells. To date, isoform-specific knockout and knockdown have been the best strategies to dissect their individual overall functions. In a recent article in the Biochemical Journal, Kajno et al. reported a new strategy to study isoform selectivity in cell lines. Individual Akt/PKB isoforms in 3T3-L1 pre-adipocytes are first silenced via shRNA and stable cellular clones lacking one or the other isoform are selected. The stably silenced isoform is then replaced by a mutant engineered to be refractory to inhibition by MK-2206 (Akt1(W80A) or Akt2(W80A)). Akt1(W80A) or Akt2(W80A) are functional and effectively recruited to the plasma membrane in response to insulin. The system affords the opportunity to acutely control the activity of the endogenous non-silenced isoform through timely addition of MK-2206. Using this approach, it is confirmed that Akt1/PKBα is the preferred isoform sustaining adipocyte differentiation, but both Akt1/PKBα and Akt2/PKBβ can indistinctly support insulin-dependent FoxO1 (forkhead box O1) nuclear exclusion. Surprisingly, either isoform can also support insulin-dependent glucose transporter (GLUT) 4 translocation to the membrane, in contrast with the preferential role of Akt2/PKBβ assessed by knockdown studies. The new strategy should allow analysis of the plurality of Akt/PKB functions in other cells and in response to other stimuli. It should also be amenable to high-throughput studies to speed up advances in signal transmission by this pivotal kinase.

  16. Precision lifetime measurements of Cs 6p 2P1/2 and 6p 2P3/2 levels by single-photon counting

    NASA Astrophysics Data System (ADS)

    Young, L.; Hill, W. T., III; Sibener, S. J.; Price, Stephen D.; Tanner, C. E.; Wieman, C. E.; Leone, Stephen R.

    1994-09-01

    Time-correlated single-photon counting is used to measure the lifetimes of the 6p 2P1/2 and 6p 2P3/2 levels in atomic Cs with accuracies ~=0.2-0.3 %. A high-repetition-rate, femtosecond, self-mode-locked Ti:sapphire laser is used to excite Cs produced in a well-collimated atomic beam. The time interval between the excitation pulse and the arrival of a fluorescence photon is measured repetitively until the desired statistics are obtained. The lifetime results are 34.75(7) and 30.41(10) ns for the 6p 2P1/2 and 6p 2P3/2 levels, respectively. These lifetimes fall between those extracted from ab initio many-body perturbation-theory calculations by Blundell, Johnson, and Sapirstein [Phys. Rev. A 43, 3407 (1991)] and V. A. Dzuba et al. [Phys. Lett. A 142, 373 (1989)] and are in all cases within 0.9% of the calculated values. The measurement errors are dominated by systematic effects, and methods to alleviate these and to approach an accuracy of 0.1% are discussed. The technique is a viable alternative to the fast-beam laser approach for measuring lifetimes with extreme accuracy.

  17. Antidepressant-like effect of novel 5-HT3 receptor antagonist N-n-butyl-3-ethoxyquinoxalin-2-carboxamide (6p): An approach using rodent behavioral antidepressant tests

    PubMed Central

    Bhatt, Shvetank; Mahesh, Radhakrishnan; Devadoss, Thangaraj; Jindal, Ankur Kumar

    2013-01-01

    Objective: The present study was designed to investigate the antidepressant potential of N-n-butyl-3-ethoxyquinoxalin-2-carboxamide (6p), a novel 5-HT3 receptor antagonist in rodent behavioral models of depression. Materials and Methods: The compound 6p was examined in various behavioral models like forced swim test (FST), tail suspension test (TST), mechanistic models [5-hydroxytryptophan (5-HTP)-induced head twitch and reserpine-induced hypothermia (RIH)], and in chronic surgery model-olfactory bulbectomy in rats. Results: Compound 6p (1, 2, and 4 mg/kg, i.p.) exhibited antidepressant-like effect in FST and TST after acute treatment without having an effect on baseline locomotor activity. Moreover, 6p (2 mg/kg, i.p.), potentiated the 5-HTP–induced head twitch responses in mice and inhibited the RIH in rats. Chronic treatment (14 days) with 6p (1 and 2 mg/kg, p.o.) and paroxetine (10 mg/kg, p.o.) in rats significantly reversed the behavioral anomalies induced by bilateral olfactory bulbectomy using open field exploration. Conclusion: The preliminary studies reveal that compound 6p exhibits antidepressant-like effect in behavioral rodent models of depression. PMID:24014909

  18. Determination of the potency of a novel saw palmetto supercritical CO2 extract (SPSE) for 5α-reductase isoform II inhibition using a cell-free in vitro test system

    PubMed Central

    Pais, Pilar; Villar, Agustí; Rull, Santiago

    2016-01-01

    Background The nicotinamide adenine dinucleotide phosphate-dependent membrane protein 5α-reductase catalyses the conversion of testosterone to the most potent androgen – 5α-dihydrotestosterone. Two 5α-reductase isoenzymes are expressed in humans: type I and type II. The latter is found primarily in prostate tissue. Saw palmetto extract (SPE) has been used extensively in the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH). The pharmacological effects of SPE include the inhibition of 5α-reductase, as well as anti-inflammatory and antiproliferative effects. Clinical studies of SPE have been inconclusive – some have shown significant results, and others have not – possibly the result of varying bioactivities of the SPEs used in the studies. Purpose To determine the in vitro potency in a cell-free test system of a novel SP supercritical CO2 extract (SPSE), an inhibitor of the 5α-reductase isoenzyme type II. Materials and methods The inhibitory potency of SPSE was compared to that of finasteride, an approved 5α-reductase inhibitor, on the basis of the enzymatic conversion of the substrate androstenedione to the 5α-reduced product 5α-androstanedione. Results By concentration-dependent inhibition of 5α-reductase type II in vitro (half-maximal inhibitory concentration 3.58±0.05 μg/mL), SPSE demonstrated competitive binding toward the active site of the enzyme. Finasteride, the approved 5α-reductase inhibitor tested as positive control, led to 63%–75% inhibition of 5α-reductase type II. Conclusion SPSE effectively inhibits the enzyme that has been linked to BPH, and the amount of extract required for activity is comparatively low. It can be confirmed from the results of this study that SPSE has bioactivity that promotes prostate health at a level that is superior to that of many other phytotherapeutic extracts. The bioactivity of SPSE corresponds favorably to that reported for the hexane extract used in a large

  19. Regulation of NADPH Oxidase 5 by Protein Kinase C Isoforms

    PubMed Central

    Chen, Feng; Yu, Yanfang; Haigh, Steven; Johnson, John; Lucas, Rudolf; Stepp, David W.; Fulton, David J. R.

    2014-01-01

    NADPH oxidase5 (Nox5) is a novel Nox isoform which has recently been recognized as having important roles in the pathogenesis of coronary artery disease, acute myocardial infarction, fetal ventricular septal defect and cancer. The activity of Nox5 and production of reactive oxygen species is regulated by intracellular calcium levels and phosphorylation. However, the kinases that phosphorylate Nox5 remain poorly understood. Previous studies have shown that the phosphorylation of Nox5 is PKC dependent, but this contention was based on the use of pharmacological inhibitors and the isoforms of PKC involved remain unknown. Thus, the major goals of this study were to determine whether PKC can directly regulate Nox5 phosphorylation and activity, to identify which isoforms are involved in the process, and to understand the functional significance of this pathway in disease. We found that a relatively specific PKCα inhibitor, Ro-32-0432, dose-dependently inhibited PMA-induced superoxide production from Nox5. PMA-stimulated Nox5 activity was significantly reduced in cells with genetic silencing of PKCα and PKCε, enhanced by loss of PKCδ and the silencing of PKCθ expression was without effect. A constitutively active form of PKCα robustly increased basal and PMA-stimulated Nox5 activity and promoted the phosphorylation of Nox5 on Ser490, Thr494, and Ser498. In contrast, constitutively active PKCε potently inhibited both basal and PMA-dependent Nox5 activity. Co-IP and in vitro kinase assay experiments demonstrated that PKCα directly binds to Nox5 and modifies Nox5 phosphorylation and activity. Exposure of endothelial cells to high glucose significantly increased PKCα activation, and enhanced Nox5 derived superoxide in a manner that was in prevented by a PKCα inhibitor, Go 6976. In summary, our study reveals that PKCα is the primary isoform mediating the activation of Nox5 and this maybe of significance in our understanding of the vascular complications of diabetes

  20. Low-frequency germline variants across 6p22.2–6p21.33 are associated with non-obstructive azoospermia in Han Chinese men

    PubMed Central

    Ni, Bixian; Lin, Yuan; Sun, Liangdan; Zhu, Meng; Li, Zheng; Wang, Hui; Yu, Jun; Guo, Xuejiang; Zuo, Xianbo; Dong, Jing; Xia, Yankai; Wen, Yang; Wu, Hao; Li, Honggang; Zhu, Yong; Ping, Ping; Chen, Xiangfeng; Dai, Juncheng; Jiang, Yue; Xu, Peng; Du, Qiang; Yao, Bing; Weng, Ning; Lu, Hui; Wang, Zhuqing; Zhu, Xiaobin; Yang, Xiaoyu; Xiong, Chenliang; Ma, Hongxia; Jin, Guangfu; Xu, Jianfeng; Wang, Xinru; Zhou, Zuomin; Liu, Jiayin; Zhang, Xuejun; Conrad, Donald F.; Hu, Zhibin; Sha, Jiahao

    2015-01-01

    Genome-wide association studies (GWAS) have identified several common loci contributing to non-obstructive azoospermia (NOA). However, a substantial fraction of NOA heritability remains undefined, especially those low-frequency [defined here as having a minor allele frequency (MAF) between 0.5 and 5%] and rare (MAF below 0.5%) variants. Here, we performed a 3-stage exome-wide association study in Han Chinese men to evaluate the role of low-frequency or rare germline variants in NOA development. The discovery stage included 962 NOA cases and 1348 healthy male controls genotyped by exome chips and was followed by a 2-stage replication with an additional 2168 cases and 5248 controls. We identified three low-frequency variants located at 6p22.2 (rs2298090 in HIST1H1E encoding p.Lys152Arg: OR = 0.30, P = 2.40 × 10−16) and 6p21.33 (rs200847762 in FKBPL encoding p.Pro137Leu: OR = 0.11, P = 3.77 × 10−16; rs11754464 in MSH5: OR = 1.78, P = 3.71 × 10−7) associated with NOA risk after Bonferroni correction. In summary, we report an instance of newly identified signals for NOA risk in genes previously undetected through GWAS on 6p22.2–6p21.33 in a Chinese population and highlight the role of low-frequency variants with a large effect in the process of spermatogenesis. PMID:26199320

  1. Modeled Microgravity-Induced Protein Kinase C Isoform Expression in Human Lymphocytes

    NASA Technical Reports Server (NTRS)

    Sundaresan, A.; Risin, D.; Pellis, N. R.

    2003-01-01

    In long-term space travel, the crew is exposed to microgravity and radiation that invoke potential hazards to the immune system. T cell activation is a critical step in the immune response. Receptor-mediated signaling is inhibited both in microgravity and modeled microgravity (MMG) as reflected in diminished DNA synthess in peripheral blood lymphocytes and their locomotion through gelled type 1 collagen. Direct activation of Protein Kinase C (PKC) bypassing cell surface events using the phorbol ester PMA rescues MMG-inhibited lymphocyte activation and locomotion, whereas calcium ionophore ionomycin had no rescue effect. Thus calcium-independent PKC isoforms may be affected in MMG-induced locomotion inhibition and rescue. Both calcium-dependent isoforms and calcium-independent PKC isoforms were investigated to assess their expression in lymphocytes in 19 and MMG-culture. Human lymphocytes were cultured and harvested at 24, 48, 72 and 96 hours and serial samples assessed for locomotion using type I collagen and expression of PKC isoforms. Expression of PKC-alpha, -delta and -epsilon was assessed by RT-PCR, flow cytometry and immunoblotting. Results indicated that PKC isoforms delta and epsilon were down-regulated by more than 50% at the transcriptional and translational levels in MMG-cultured lymphocytes compared with 19 controls. Events upstream of PKC such as phosphorylation of Phospholipase C(gamma) (PLC-gamma) in MMG, revealed accumulation of inactive enzyme. Depressed Ca++ -independent PKC isoforms may be a consequence of an upstream lesion in the signal transduction pathway. The differential response among calcium-dependent and calcium-independent isoforms may actually result from MMG intrusion events earlier than, but after ligand-receptor interaction. Keywords: Signal transduction, locomotion, immunity

  2. Modeled microgravity-induced protein kinase C isoform expression in human lymphocytes

    NASA Technical Reports Server (NTRS)

    Sundaresan, A.; Risin, D.; Pellis, N. R.

    2004-01-01

    In long-term space travel, the crew is exposed to microgravity and radiation that invoke potential hazards to the immune system. T cell activation is a critical step in the immune response. Receptor-mediated signaling is inhibited in both microgravity and modeled microgravity (MMG) as reflected by diminished DNA synthesis in peripheral blood lymphocytes and their locomotion through gelled type I collagen. Direct activation of protein kinase C (PKC) bypassing cell surface events using the phorbol ester PMA rescues MMG-inhibited lymphocyte activation and locomotion, whereas the calcium ionophore ionomycin had no rescue effect. Thus calcium-independent PKC isoforms may be affected in MMG-induced locomotion inhibition and rescue. Both calcium-dependent isoforms and calcium-independent PKC isoforms were investigated to assess their expression in lymphocytes in 1 g and MMG culture. Human lymphocytes were cultured and harvested at 24, 48, 72, and 96 h, and serial samples were assessed for locomotion by using type I collagen and expression of PKC isoforms. Expression of PKC-alpha, -delta, and -epsilon was assessed by RT-PCR, flow cytometry, and immunoblotting. Results indicated that PKC isoforms delta and epsilon were downregulated by >50% at the transcriptional and translational levels in MMG-cultured lymphocytes compared with 1-g controls. Events upstream of PKC, such as phosphorylation of phospholipase Cgamma in MMG, revealed accumulation of inactive enzyme. Depressed calcium-independent PKC isoforms may be a consequence of an upstream lesion in the signal transduction pathway. The differential response among calcium-dependent and calcium-independent isoforms may actually result from MMG intrusion events earlier than PKC, but after ligand-receptor interaction.

  3. Glutaminases in brain: Multiple isoforms for many purposes.

    PubMed

    Campos-Sandoval, José A; Martín-Rufián, Mercedes; Cardona, Carolina; Lobo, Carolina; Peñalver, Ana; Márquez, Javier

    2015-09-01

    Glutaminase is expressed in most mammalian tissues and cancer cells, but recent studies are now revealing a considerably degree of complexity in its pattern of expression and functional regulation. Novel transcript variants of the mammalian glutaminase Gls2 gene have been recently found and characterized in brain. Co-expression of different isoforms in the same cell type would allow cells to fine-tune their Gln/Glu levels under a wide range of metabolic states. Moreover, the discovery of protein interacting partners and novel subcellular localizations, for example nucleocytoplasmic in neurons and astrocytes, strongly suggest non-neurotransmission roles for Gls2 isoforms associated with transcriptional regulation and cellular differentiation. Of note, Gls isoforms have been considered as an important trophic factor for neuronal differentiation and postnatal development of brain regions. On the other hand, glutaminases are taking center stage in tumor biology as new therapeutic targets to inhibit metabolic reprogramming of cancer cells. Interestingly, glutaminase isoenzymes play seemingly opposing roles in cancer cell growth and proliferation; this issue will be also succinctly discussed with special emphasis on brain tumors.

  4. Enhanced expression of two discrete isoforms of matrix metalloproteinase-2 in experimental and human diabetic nephropathy

    PubMed Central

    Bae, Sun Sik; Lee, Min Young; Rhee, Harin; Kim, Il Young; Seong, Eun Young; Lee, Dong Won; Lee, Soo Bong; Kwak, Ihm Soo; Lovett, David H.

    2017-01-01

    Background We recently reported on the enhanced expression of two isoforms of matrix metalloproteinase-2 (MMP-2) in human renal transplantation delayed graft function. These consist of the conventional secreted, full length MMP-2 isoform (FL-MMP-2) and a novel intracellular N-Terminal Truncated isoform (NTT-MMP-2) generated by oxidative stress-mediated activation of an alternate promoter in the MMP-2 first intron. Here we evaluated the effect of hyperglycemia and diabetes mellitus on the in vitro and in vivo expression of the two MMP-2 isoforms. Methods We quantified the abundance of the FL-MMP-2 and NTT-MMP-2 transcripts by qPCR in HK2 cells cultured in high glucose or 4-hydroxy-2-hexenal (HHE) and tested the effects of the NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC). The streptozotocin (STZ) murine model of Type I diabetes mellitus and renal biopsies of human diabetic nephropathy were used in this study. Results Both isoforms of MMP-2 in HK2 cells were upregulated by culture in high glucose or with HHE. PDTC treatment did not suppress high glucose-mediated FL-MMP-2 expression but potently inhibited NTT-MMP-2 expression. With STZ-treated mice, renal cortical expression of both isoforms was increased (FL-MMP-2, 1.8-fold; NTT-MMP-2, greater than 7-fold). Isoform-specific immunohistochemical staining revealed low, but detectable levels of the FL-MMP-2 isoform in controls, while NTT-MMP-2 was not detected. While there was a modest increase in tubular epithelial cell staining for FL-MMP-2 in STZ-treated mice, NTT-MMP-2 was intensely expressed in a basolateral pattern. FL-MMP-2 and NTT-MMP-2 isoform expression as quantified by qPCR were both significantly elevated in renal biopsies of human diabetic nephropathy (12-fold and 3-fold, respectively). Conclusions The expression of both isoforms of MMP-2 was enhanced in an experimental model of diabetic nephropathy and in human diabetic nephropathy. Selective MMP-2 isoform inhibition could offer a novel approach for

  5. RSK isoforms in cancer cell invasion and metastasis.

    PubMed

    Sulzmaier, Florian J; Ramos, Joe W

    2013-10-15

    Metastasis, the spreading of cancer cells from a primary tumor to secondary sites throughout the body, is the primary cause of death for patients with cancer. New therapies that prevent invasion and metastasis in combination with current treatments could therefore significantly reduce cancer recurrence and morbidity. Metastasis is driven by altered signaling pathways that induce changes in cell-cell adhesion, the cytoskeleton, integrin function, protease expression, epithelial-to-mesenchymal transition and cell survival. The ribosomal S6 kinase (RSK) family of kinases is a group of extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) effectors that can regulate these steps of metastasis by phosphorylating both nuclear and cytoplasmic targets. However, our understanding of RSK function in metastasis remains incomplete and is complicated by the fact that the four RSK isoforms perform nonredundant, sometimes opposing functions. Although some isoforms promote cell motility and invasion by altering transcription and integrin activity, others impair cell motility and invasion through effects on the actin cytoskeleton. The mechanism of RSK action depends both on the isoform and the cancer type. However, despite the variance in RSK-mediated outcomes, chemical inhibition of this group of kinases has proven effective in blocking invasion and metastasis of several solid tumors in preclinical models. RSKs are therefore a promising drug target for antimetastatic cancer treatments that could supplement and improve current therapeutic approaches. This review highlights contradiction and agreement in the current data on the function of RSK isoforms in metastasis and suggests ways forward in developing RSK inhibitors as new antimetastasis drugs.

  6. Purification and characterization of two isoforms of isopentenyl-diphosphate isomerase from elicitor-treated Cinchona robusta cells.

    PubMed

    Ramos-Valdivia, A C; van der Heijden, R; Verpoorte, R; Camara, B

    1997-10-01

    In Cinchona robusta (Rubiaceae) cell suspension cultures, the activity of the enzyme isopentenyl-diphosphate isomerase (isopentenyl-POP isomerase) is transiently induced after addition of a homogenate of the phytopathogenic fungus Phytophthora cinnamomi. The enzyme catalyses the interconversion of isopentenyl-POP and dimethylallyl diphosphate (dimethylallyl-POP) and may be involved in the biosynthesis of anthraquinone phytoalexins that accumulate rapidly after elicitation of Cinchona cells. From elicitor-treated C. robusta cells, two isoforms of isopentenyl-POP isomerase have been purified to apparent homogeneity in four chromatographic steps. The purified forms are monomeric enzymes of 34 kDa (isoform I) and 29 kDa (isoform II), with Km values for isopentenyl-POP of 5.1 microM and 1.0 microM, respectively. Both isoforms require Mn2+ or Mg2+ as cofactor, isoform II showing a preference for Mn2+ with maximum activity at 1.5-2 mM. Isoform I was most active in the presence of 0.5-1.5 mM Mg2+ or in the presence of 0.5 mM Mn2+. A pH optimum of 7-7.8 was found for both forms and both were competitively inhibited by geranyl diphosphate (Ki 96 microM for isoform I) and the transition state analogue 2-(dimethylamino)ethyl diphosphate. Rechromatography of purified isoforms did not indicate any interconversion of both forms. Western blot analysis, using antibodies raised against isopentenyl-POP isomerase purified from Capsicum annuum, showed the presence of both isoforms in the crude protein extracts from C. robusta cells. Isoform II was specifically induced by elicitation, non-treated cells contained low activity of this isoform. The possible role of isopentenyl-POP isomerase in the biosynthesis of anthraquinones is discussed.

  7. Determining the Volatile Inventory of Jupiter-Family Comet 6P/d?Arrest

    NASA Astrophysics Data System (ADS)

    Dello Russo, Neil

    2008-02-01

    We propose to measure the chemical composition in 6P/d?Arrest, a short-period Jupiter-family comet (JFC) of probable Kuiper-belt origin. 6P will pass close to Earth and is available for a significant amount of dark time at Keck during its 2008 apparition creating excellent observing conditions. Determining the chemical composition of 6P will help address several important scientific questions. First, JFCs are generally too faint to allow detailed spectroscopic investigations, but this apparition of 6P/d?Arrest is exceptional in that regard. We propose a sensitive search for the following molecular species in 6P: H2O, CO, CH4, CH3OH, H2CO, C2H6, HCN, C2H2, and NH3. Second, chemical differences are seen within the JFC population. Are these differences primordial or due to evolution? Comparison of the chemistry of parent volatile species within JFCs will provide insights into the role of solar system formation conditions and processing in determining comet composition.

  8. Influence of development on Na(+)/K(+)-ATPase expression: isoform- and tissue-dependency.

    PubMed

    Lopez, Luciane B; Quintas, Luis Eduardo M; Noël, François

    2002-02-01

    The four isoforms of the catalytic subunit of Na(+)/K(+)-ATPase identified in rats differ in their affinities for ions and ouabain. Moreover, its expression is tissue-specific, developmentally and hormonally regulated. The aim of the present work was to evaluate the influence of age on the ratio and density of these isoforms in crude membrane preparations from rat brain hemispheres, brainstem, heart ventricles and kidneys. In all tissues investigated, Na(+)/K(+)-ATPase activity was higher in adults than in neonates but brain tissues presented the most remarkable differences. In these tissues, ouabain inhibition curves for Na(+)/K(+)-ATPase activity revealed the presence of two processes with different sensitivities to ouabain. An increase of approximately sixfold in the expression of the high affinity isoforms was observed between newborn and adult rats. In contrast, the low affinity isoform increased only approximately twofold in brainstem whereas it increased ninefold in brain hemispheres. Unlike brain tissues, a decrease (almost fourfold) in the number of high affinity ouabain binding sites was observed during ontogenesis of the heart. Although limited by the inability to resolve alpha(2) and alpha(3) isoforms, present data indicate that the influence of development on the expression of Na(+)/K(+)-ATPase depends not only on the isoform, but also on the tissue where the enzyme is expressed.

  9. Physical map of human 6p21.2-6p21.3: region flanking the centromeric end of the major histocompatibility complex.

    PubMed

    Tripodis, N; Mason, R; Humphray, S J; Davies, A F; Herberg, J A; Trowsdale, J; Nizetic, D; Senger, G; Ragoussis, J

    1998-06-01

    We have physically mapped and cloned a 2.5-Mb chromosomal segment flanking the centromeric end of the major histocompatibility complex (MHC). We characterized in detail 27 YACs, 144 cosmids, 51 PACs, and 5 BACs, which will facilitate the complete genomic sequencing of this region of chromosome 6. The contig contains the genes encoding CSBP, p21, HSU09564 serine kinase, ZNF76, TCP-11, RPS10, HMGI(Y), BAK, and the human homolog of Tctex-7 (HSET). The GLO1 gene was mapped further centromeric in the 6p21.2-6p21.1 region toward TCTE-1. The gene order of the GLO1-HMGI(Y) segment in respect to the centromere is similar to the gene order in the mouse t-chromosome distal inversion, indicating that there is conservation in gene content but not gene order between humans and mice in this region. The close linkage of the BAK and CSBP genes to the MHC is of interest because of their possible involvement in autoimmune disease.

  10. Role of ROCK Isoforms in Regulation of Stiffness Induced Myofibroblast Differentiation in Lung Fibrosis.

    PubMed

    Htwe, Su S; Cha, Byung H; Yue, Kan; Khademhosseini, Ali; Knox, Alan J; Ghaemmaghami, Amir M

    2017-02-22

    Fibrosis is a major cause of progressive organ dysfunction in several chronic pulmonary diseases. Rho associated coiled-coil forming kinase (ROCK) has shown to be involved in myofibroblast differentiation driven by altered matrix stiffness in fibrotic state. There are two known ROCK isoforms in human, ROCK1 (ROKβ) and ROCK2 (ROKα), but specific role of each isoform in myofibroblast differentiation in lung fibrosis remains unknown. To study this, we developed a Gelatin methacryloyl (GelMA) hydrogel based culture system with different stiffness levels relevant to healthy and fibrotic lungs. We have shown that stiff matrix and not soft matrix, can induce myofibroblast differentiation with high αSMA expression. Furthermore, our data confirm that the inhibition of ROCK signalling by a pharmacological inhibitor (i.e. Y27632) attenuates stiffness induced αSMA expression and fibre assembly in myofibroblasts. To assess the role of ROCK isoforms in this process we used siRNA to knock down the expression of each isoform. Our data showed that knocking down either ROCK1 or ROCK2 did not result in a reduction in αSMA expression in myofibroblasts on stiff matrix as opposed to soft matrix where αSMA expression was reduced significantly. Paradoxically, on stiff matrix, the absence of one isoform (particularly ROCK2) exaggerated αSMA expression and led to thick fibre assembly. Moreover complete loss of αSMA fibre assembly was seen only in the absence of both ROCK isoforms suggesting that both isoforms are implicated in this process. Overall our results indicate the differential role of ROCK isoforms in myofibroblast differentiation on soft and stiff matrices.

  11. Isoform-Specific SCFFbw7 Ubiquitination Mediates Differential Regulation of PGC-1α

    PubMed Central

    Trausch-Azar, Julie S.; Abed, Mona; Orian, Amir; Schwartz, Alan L.

    2015-01-01

    The E3 ubiquitin ligase and tumor suppressor SCFFbw7 exists as three isoforms that govern the degradation of a host of critical cell regulators, including c-Myc, cyclin E, and PGC-1α. Peroxisome proliferator activated receptor-gamma coactivator 1α (PGC-1α) is a transcriptional coactivator with broad effects on cellular energy metabolism. Cellular PGC-1α levels are tightly controlled in a dynamic state by the balance of synthesis and rapid degradation via the ubiquitin-proteasome system. Yet, isoform-specific functions of SCFFbw7 are yet to be determined. Here, we show that the E3 ubiquitin ligase, SCFFbw7, regulates cellular PGC-1α levels via two independent, isoform specific, mechanisms. The cytoplasmic isoform (SCFFbw7β) reduces cellular PGC-1α levels via accelerated ubiquitin-proteasome degradation. In contrast, the nuclear isoform (SCFFbw7α) increases cellular PGC-1α levels and protein stability via inhibition of ubiquitin-proteasomal degradation. When nuclear Fbw7α proteins are redirected to the cytoplasm, cellular PGC-1α protein levels are reduced through accelerated ubiquitin-proteasomal degradation. We find that SCFFbw7β catalyzes high molecular weight PGC-1α-ubiquitin conjugation, whereas SCFFbw7α produces low molecular weight PGC-1α-ubiquitin conjugates that are not effective degradation signals. Thus, selective ubiquitination by specific Fbw7 isoforms represents a novel mechanism that tightly regulates cellular PGC-1α levels. Fbw7 isoforms mediate degradation of a host of regulatory proteins. The E3 ubiquitin ligase, Fbw7, mediates PGC-1α levels via selective isoform-specific ubiquitination. Fbw7β reduces cellular PGC-1α via ubiquitin-mediated degradation, whereas Fbw7α increases cellular PGC-1α via ubiquitin-mediated stabilization. PMID:25204433

  12. Modulation of estrogen receptor-beta isoforms by phytoestrogens in breast cancer cells.

    PubMed

    Cappelletti, Vera; Miodini, Patrizia; Di Fronzo, Giovanni; Daidone, Maria Grazia

    2006-05-01

    High consumption of phytoestrogen-rich food correlates with reduced incidence of breast cancer. However, the effect of phytoestrogens on growth of pre-existing breast tumors presents concerns when planning the use of phytoestrogens as chemoprevention st rategy. Genistein, the active phytoestrogen in soy, displays weak estrogenic activity mediated by estrogen receptor (ER) with a preferential binding for the ER-beta species. However, no information is at present available on the interaction between phytoestrogens and the various isoforms generated by alternative splicing. In two human breast cancer cell lines, T47D and BT20, which express variable levels of ER-beta, the effect of genistein and quercetin was evaluated singly and in comparison with 17beta-estradiol, on mRNA expression of estrogen receptor-beta (ER-beta) isoforms evaluated by a triple primer RT-PCR assay. In T47D cells estradiol caused a 6-fold up-regulation of total ER-beta, and modified the relative expression pattern of the various isoforms, up-regulating the beta2 and down-regulating the beta5 isoform. Genistein up-regulated ER-beta2 and ER-beta1 in T47D cells, and after treatment the ER-beta2 isoform became prevalent, while in BT20 cells it almost doubled the percent contribution of ER-beta1 and ER-beta2 to total ER-beta. Quercetin did not alter the total levels nor the percent distribution of ER-beta isoforms in either cell line. Genistein, through the modulation of ER-beta isoform RNA expression inhibited estrogen-promoted cell growth, without interfering on estrogen-regulated transcription. ER-beta and its ER-beta mRNA isoforms may be involved in a self-limiting mechanism of estrogenic stimulation promoted either by the natural hormone or by weaker estrogen agonists like genistein.

  13. Involvement of the antioxidative property of morusin in blocking phorbol ester-induced malignant transformation of JB6 P(+) mouse epidermal cells.

    PubMed

    Cheng, Pai-Shan; Hu, Chao-Chin; Wang, Chau-Jong; Lee, Yean-Jang; Chung, Wei-Chia; Tseng, Tsui-Hwa

    2017-02-25

    Chemoprevention has been acknowledged as an important and practical strategy for managing cancer. We have previously synthesized morusin, a prenylated flavonoid that exhibits anti-cancer progression activity. In the present study, we evaluated the anti-cancer promotion potential of morusin by using the mouse epidermal JB6 P(+) cell model. Extensive evidence shows that tumor promotion by phorbol esters is due to the stimulation of reactive oxygen species (ROS). Therefore, the effect of morusin on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced ROS production was assessed. Noncytotoxic concentrations of morusin were found to dose-dependently reduce TPA-induced ROS production. Moreover, morusin inhibited TPA-induced activator protein-1 (AP-1) and nuclear factor-kappa B (NF-κB) activation, which can mediate cell proliferation and malignant transformation. Furthermore, morusin inhibited the TPA upregulation of cyclooxygenase 2 (COX-2), which may be regulated by AP-1 and NF-κB. In addition, noncytotoxic concentrations of morusin reduced the TPA-promoted cell growth of JB6 P(+) cells and inhibited TPA-induced malignant properties, such as cytoskeletal rearrangement and cell migration of JB6 P(+) cells. Similar to the effects of glutathione (GSH) pretreatment, morusin inhibited TPA-induced expression of N-cadeherin and vimentin, which are malignant cell surface proteins. Finally, morusin treatment dose-dependently suppressed the TPA-induced anchorage-independent cell transformation of JB6 P(+) cells. In conclusion, our results evidence that morusin possesses anti-cancer promotion potential because of its antioxidant property, which mediates multiple transformation-associated gene expression.

  14. AMPK activation represses the human gene promoter of the cardiac isoform of acetyl-CoA carboxylase: Role of nuclear respiratory factor-1

    SciTech Connect

    Adam, Tasneem; Opie, Lionel H.; Essop, M. Faadiel

    2010-07-30

    Research highlights: {yields} AMPK inhibits acetyl-CoA carboxylase beta gene promoter activity. {yields} Nuclear respiratory factor-1 inhibits acetyl-CoA carboxylase beta promoter activity. {yields} AMPK regulates acetyl-CoA carboxylase beta at transcriptional level. -- Abstract: The cardiac-enriched isoform of acetyl-CoA carboxylase (ACC{beta}) produces malonyl-CoA, a potent inhibitor of carnitine palmitoyltransferase-1. AMPK inhibits ACC{beta} activity, lowering malonyl-CoA levels and promoting mitochondrial fatty acid {beta}-oxidation. Previously, AMPK increased promoter binding of nuclear respiratory factor-1 (NRF-1), a pivotal transcriptional modulator controlling gene expression of mitochondrial proteins. We therefore hypothesized that NRF-1 inhibits myocardial ACC{beta} promoter activity via AMPK activation. A human ACC{beta} promoter-luciferase construct was transiently transfected into neonatal cardiomyocytes {+-} a NRF-1 expression construct. NRF-1 overexpression decreased ACC{beta} gene promoter activity by 71 {+-} 4.6% (p < 0.001 vs. control). Transfections with 5'-end serial promoter deletions revealed that NRF-1-mediated repression of ACC{beta} was abolished with a pPII{beta}-18/+65-Luc deletion construct. AMPK activation dose-dependently reduced ACC{beta} promoter activity, while NRF-1 addition did not further decrease it. We also investigated NRF-1 inhibition in the presence of upstream stimulatory factor 1 (USF1), a known transactivator of the human ACC{beta} gene promoter. Here NRF-1 blunted USF1-dependent induction of ACC{beta} promoter activity by 58 {+-} 7.5% (p < 0.001 vs. control), reversed with a dominant negative NRF-1 construct. NRF-1 also suppressed endogenous USF1 transcriptional activity by 55 {+-} 6.2% (p < 0.001 vs. control). This study demonstrates that NRF-1 is a novel transcriptional inhibitor of the human ACC{beta} gene promoter in the mammalian heart. Our data extends AMPK regulation of ACC{beta} to the transcriptional level.

  15. Mitochondrial localization of the OAS1 p46 isoform associated with a common single nucleotide polymorphism

    PubMed Central

    2014-01-01

    Background The expression of 2′-5′-Oligoadenylate synthetases (OASs) is induced by type 1 Interferons (IFNs) in response to viral infection. The OAS proteins have a unique ability to produce 2′-5′ Oligoadenylates, which bind and activate the ribonuclease RNase L. The RNase L degrades cellular RNAs which in turn inhibits protein translation and induces apoptosis. Several single nucleotide polymorphisms (SNPs) in the OAS1 gene have been associated with disease. We have investigated the functional effect of two common SNPs in the OAS1 gene. The SNP rs10774671 affects splicing to one of the exons in the OAS1 gene giving rise to differential expression of the OAS1 isoforms, and the SNP rs1131454 (former rs3741981) resides in exon 3 giving rise to OAS1 isoforms with either a Glycine or a Serine at position 162 in the core OAS unit. Results We have used three human cell lines with different genotypes in the OAS1 SNP rs10774671, HeLa cells with the AA genotype, HT1080 cells with AG, and Daudi cells with GG. The main OAS1 isoform expressed in Daudi and HT1080 cells was p46, and the main OAS1 isoform expressed in HeLa cells was p42. In addition, low levels of the OAS1 p52 mRNA was detected in HeLa cells and p48 mRNA in Daudi cells, and trace amounts of p44a mRNA were detected in the three cell lines treated with type 1 interferon. We show that the OAS1 p46 isoform was localized in the mitochondria in Daudi cells, whereas the OAS1 isoforms in HeLa cells were primarily localized in cytoplasmic vacuoles/lysosomes. By using recombinantly expressed OAS1 mutant proteins, we found that the OAS1 SNP rs1131454 (former rs3741981) did not affect the enzymatic OAS1 activity. Conclusions The SNP rs10774671 determines differential expression of the OAS1 isoforms. In Daudi and HT1080 cells the p46 isoform is the most abundantly expressed isoform associated with the G allele, whereas in HeLa cells the most abundantly expressed isoform is p42 associated with the A allele. The SNP rs

  16. Isoform Specificity of Protein Kinase Cs in Synaptic Plasticity

    ERIC Educational Resources Information Center

    Sossin, Wayne S.

    2007-01-01

    Protein kinase Cs (PKCs) are implicated in many forms of synaptic plasticity. However, the specific isoform(s) of PKC that underlie(s) these events are often not known. We have used "Aplysia" as a model system in order to investigate the isoform specificity of PKC actions due to the presence of fewer isoforms and a large number of documented…

  17. GH1-family 6-P-β-glucosidases from human microbiome lactic acid bacteria

    PubMed Central

    Michalska, Karolina; Tan, Kemin; Li, Hui; Hatzos-Skintges, Catherine; Bearden, Jessica; Babnigg, Gyorgy; Joachimiak, Andrzej

    2013-01-01

    In lactic acid bacteria and other bacteria, carbohydrate uptake is mostly governed by phosphoenolpyruvate-dependent phosphotransferase systems (PTSs). PTS-dependent translocation through the cell membrane is coupled with phosphorylation of the incoming sugar. After translocation through the bacterial membrane, the β-glycosidic bond in 6′-­P-­β-glucoside is cleaved, releasing 6-P-β-glucose and the respective aglycon. This reaction is catalyzed by 6-P-β-glucosidases, which belong to two glycoside hydrolase (GH) families: GH1 and GH4. Here, the high-resolution crystal structures of GH1 6-P-β-glucosidases from Lactobacillus plantarum (LpPbg1) and Streptococcus mutans (SmBgl) and their complexes with ligands are reported. Both enzymes show hydrolytic activity towards 6′-P-β-glucosides. The LpPbg1 structure has been determined in an apo form as well as in a complex with phosphate and a glucose molecule corresponding to the aglycon molecule. The S. mutans homolog contains a sulfate ion in the phosphate-dedicated subcavity. SmBgl was also crystallized in the presence of the reaction product 6-P-β-glucose. For a mutated variant of the S. mutans enzyme (E375Q), the structure of a 6′-P-salicin complex has also been determined. The presence of natural ligands enabled the definition of the structural elements that are responsible for substrate recognition during catalysis. PMID:23519420

  18. Non-Classical Inhibition of Carbonic Anhydrase

    PubMed Central

    Lomelino, Carrie L.; Supuran, Claudiu T.; McKenna, Robert

    2016-01-01

    Specific isoforms from the carbonic anhydrase (CA) family of zinc metalloenzymes have been associated with a variety of diseases. Isoform-specific carbonic anhydrase inhibitors (CAIs) are therefore a major focus of attention for specific disease treatments. Classical CAIs, primarily sulfonamide-based compounds and their bioisosteres, are examined as antiglaucoma, antiepileptic, antiobesity, antineuropathic pain and anticancer compounds. However, many sulfonamide compounds inhibit all CA isoforms nonspecifically, diluting drug effectiveness and causing undesired side effects due to off-target inhibition. In addition, a small but significant percentage of the general population cannot be treated with sulfonamide-based compounds due to a sulfa allergy. Therefore, CAIs must be developed that are not only isoform specific, but also non-classical, i.e. not based on sulfonamides, sulfamates, or sulfamides. This review covers the classes of non-classical CAIs and the recent advances in the development of isoform-specific inhibitors based on phenols, polyamines, coumarins and their derivatives. PMID:27438828

  19. The MF6p/FhHDM-1 Major Antigen Secreted by the Trematode Parasite Fasciola hepatica Is a Heme-binding Protein*

    PubMed Central

    Martínez-Sernández, Victoria; Mezo, Mercedes; González-Warleta, Marta; Perteguer, María J.; Muiño, Laura; Guitián, Esteban; Gárate, Teresa; Ubeira, Florencio M.

    2014-01-01

    Blood-feeding parasites have developed biochemical mechanisms to control heme intake and detoxification. Here we show that a major antigen secreted by Fasciola hepatica, previously reported as MF6p, of unknown function (gb|CCA61804.1), and as FhHDM-1, considered to be a helminth defense molecule belonging to the family of cathelicidin-like proteins (gb|ADZ24001.1), is in fact a heme-binding protein. The heme-binding nature of the MF6p/FhHDM-1 protein was revealed in two independent experiments: (i) immunopurification of the secreted protein·heme complexes with mAb MF6 and subsequent analysis by C8 reversed-phase HPLC and MS/MS spectrometry and (ii) analysis of the binding ability of the synthetic protein to hemin in vitro. By immunohistochemistry analysis, we have observed that MF6p/FhHDM-1 is produced by parenchymal cells and transported to other tissues (e.g. vitellaria and testis). Interestingly, MF6p/FhHDM-1 is absent both in the intestinal cells and in the lumen of cecum, but it can be released through the tegumental surface to the external medium, where it binds to free heme molecules regurgitated by the parasite after hemoglobin digestion. Proteins that are close analogs of the Fasciola MF6p/FhHDM-1 are present in other trematodes, including Clonorchis, Opistorchis, Paragonimus, Schistosoma, and Dicrocoelium. Using UV-visible spectroscopy and immunoprecipitation techniques, we observed that synthetic MF6p/FhHDM-1 binds to hemin with 1:1 stoichiometry and an apparent Kd of 1.14 × 10−6 m−1. We also demonstrated that formation of synthetic MF6p/FhHDM-1·hemin complexes inhibited hemin degradation by hydrogen peroxide and hemin peroxidase-like activity in vitro. Our results suggest that MF6p/FhHDM-1 may be involved in heme homeostasis in trematodes. PMID:24280214

  20. Characterization of endogenous human promyelocytic leukemia isoforms.

    PubMed

    Condemine, Wilfried; Takahashi, Yuki; Zhu, Jun; Puvion-Dutilleul, Francine; Guegan, Sarah; Janin, Anne; de Thé, Hugues

    2006-06-15

    Promyelocytic leukemia (PML) has been implicated in a variety of functions, including control of TP53 function and modulation of cellular senescence. Sumolated PML is the organizer of mature PML bodies, recruiting a variety of proteins onto these nuclear domains. The PML gene is predicted to encode a variety of protein isoforms. Overexpression of only one of them, PML-IV, promotes senescence in human diploid fibroblasts, whereas PML-III was proposed to specifically interact with the centrosome. We show that all PML isoform proteins are expressed in cell lines or primary cells. Unexpectedly, we found that PML-III, PML-IV, and PML-V are quantitatively minor isoforms compared with PML-I/II and could not confirm the centrosomal targeting of PML-III. Stable expression of each isoform, in a pml-null background, yields distinct subcellular localization patterns, suggesting that, like in other RBCC/TRIM proteins, the COOH-terminal domains of PML are involved in interactions with specific cellular components. Only the isoform-specific sequences of PML-I and PML-V are highly conserved between man and mouse. That PML-I contains all conserved exons and is more abundantly expressed than PML-IV suggests that it is a critical contributor to PML function(s).

  1. Absolute Quantification of Endogenous Ras Isoform Abundance

    PubMed Central

    Mageean, Craig J.; Griffiths, John R.; Smith, Duncan L.; Clague, Michael J.; Prior, Ian A.

    2015-01-01

    Ras proteins are important signalling hubs situated near the top of networks controlling cell proliferation, differentiation and survival. Three almost identical isoforms, HRAS, KRAS and NRAS, are ubiquitously expressed yet have differing biological and oncogenic properties. In order to help understand the relative biological contributions of each isoform we have optimised a quantitative proteomics method for accurately measuring Ras isoform protein copy number per cell. The use of isotopic protein standards together with selected reaction monitoring for diagnostic peptides is sensitive, robust and suitable for application to sub-milligram quantities of lysates. We find that in a panel of isogenic SW48 colorectal cancer cells, endogenous Ras proteins are highly abundant with ≥260,000 total Ras protein copies per cell and the rank order of isoform abundance is KRAS>NRAS≥HRAS. A subset of oncogenic KRAS mutants exhibit increased total cellular Ras abundance and altered the ratio of mutant versus wild type KRAS protein. These data and methodology are significant because Ras protein copy number is required to parameterise models of signalling networks and informs interpretation of isoform-specific Ras functional data. PMID:26560143

  2. Probing the surface of human carbonic anhydrase for clues towards the design of isoform specific inhibitors.

    PubMed

    Pinard, Melissa A; Mahon, Brian; McKenna, Robert

    2015-01-01

    The alpha carbonic anhydrases (α-CAs) are a group of structurally related zinc metalloenzymes that catalyze the reversible hydration of CO2 to HCO3(-). Humans have 15 different α-CAs with numerous physiological roles and expression patterns. Of these, 12 are catalytically active, and abnormal expression and activities are linked with various diseases, including glaucoma and cancer. Hence there is a need for CA isoform specific inhibitors to avoid off-target CA inhibition, but due to the high amino acid conservation of the active site and surrounding regions between each enzyme, this has proven difficult. However, residues towards the exit of the active site are variable and can be exploited to design isoform selective inhibitors. Here we discuss and characterize this region of "selective drug targetability" and how these observations can be utilized to develop isoform selective CA inhibitors.

  3. Probing the Surface of Human Carbonic Anhydrase for Clues towards the Design of Isoform Specific Inhibitors

    PubMed Central

    Pinard, Melissa A.

    2015-01-01

    The alpha carbonic anhydrases (α-CAs) are a group of structurally related zinc metalloenzymes that catalyze the reversible hydration of CO2 to HCO3−. Humans have 15 different α-CAs with numerous physiological roles and expression patterns. Of these, 12 are catalytically active, and abnormal expression and activities are linked with various diseases, including glaucoma and cancer. Hence there is a need for CA isoform specific inhibitors to avoid off-target CA inhibition, but due to the high amino acid conservation of the active site and surrounding regions between each enzyme, this has proven difficult. However, residues towards the exit of the active site are variable and can be exploited to design isoform selective inhibitors. Here we discuss and characterize this region of “selective drug targetability” and how these observations can be utilized to develop isoform selective CA inhibitors. PMID:25811028

  4. A gene for hypotrichosis simplex of the scalp maps to chromosome 6p21.3.

    PubMed Central

    Betz, R C; Lee, Y A; Bygum, A; Brandrup, F; Bernal, A I; Toribio, J; Alvarez, J I; Kukuk, G M; Ibsen, H H; Rasmussen, H B; Wienker, T F; Reis, A; Propping, P; Kruse, R; Cichon, S; Nöthen, M M

    2000-01-01

    Hypotrichosis simplex of the scalp (HSS) is an autosomal dominant form of isolated alopecia causing almost complete loss of scalp hair, with onset in childhood. After exclusion of candidate regions previously associated with hair-loss disorders, we performed a genomewide linkage analysis in two Danish families and localized the gene to chromosome 6p21.3. This was confirmed in a Spanish family, with a total LOD score of 11.97 for marker D6S1701 in all families. The combined haplotype data identify a critical interval of 14.9 cM between markers D6S276 and D6S1607. Localization of the locus for HSS to 6p21.3 is a first step toward identification of the gene. The gene will give important insights into the molecular and cellular basis of hair growth on the scalp. PMID:10793007

  5. Brachydactyly type E in an Italian family with 6p25 trisomy.

    PubMed

    Fontana, Paolo; Tortora, Cristina; Petillo, Roberta; Malacarne, Michela; Cavani, Simona; Miniero, Martina; D'Ambrosio, Paola; De Brasi, Davide; Pisanti, Maria Antonietta

    2017-03-01

    Brachydactyly type E is a congenital limb malformation characterized by small hands and feet as a result of shortened metacarpals and metatarsals. Genetic causes of this anomaly are heterogeneous and only partially characterized. In this report we describe an Italian family in which four subjects share brachydactyly type E and a 3 Mb microduplication in region 6p25. The duplication involves the gene FOXC1, expressed during the osteoblast differentiation, which appears a potential candidate gene for brachydactyly.

  6. Pyrophosphate Fructose-6-P 1-Phosphotransferase from Tomato Fruit : Evidence for Change during Ripening.

    PubMed

    Wong, J H; Kiss, F; Wu, M X; Buchanan, B B

    1990-10-01

    Three forms of pyrophosphate fructose-6-phosphate 1-phosphotransferase (PFP) were purified from both green and red tomato (Lycopersicon esculentum) fruit: (a) a classical form (designated Q(2)) containing alpha- (66 kilodalton) and beta- (60 kilodalton) subunits; (b) a form (Q(1)) containing a beta-doublet subunit; and (c) a form (Q(0)) that appeared to contain a beta-singlet subunit. Several lines of evidence suggested that the different forms occur under physiological conditions. Q(2) was purified to apparent electrophoretic homogeneity; Q(1) and Q(0) were highly purified, but not to homogeneity. The distribution of the PFP forms from red (versus green) tomato was: Q(2), 29% (90%); Q(1), 47% (6%); and Q(0), 24% (4%). The major difference distinguishing the red from the green tomato enzymes was the fructose-2,6-bisphosphate (Fru-2,6-P(2))-induced change in K(m) for fructose-6-phosphate (Fru-6-P), the ;green forms' showing markedly enhanced affinity on activation (K(m) decrease of 7-9-fold) and the ;red forms' showing either little change (Q(0), Q(1)) or a relatively small (2.5-fold) affinity increase (Q(2)). The results extend our earlier findings with carrot root to another tissue and indicate that forms of PFP showing low or no affinity increase for Fru 6-P on activation by Fru-2,6-P(2) (here Q(1) and Q(0)) are associated with sugar storage, whereas the classical form (Q(2)), which shows a pronounced affinity increase, is more important for starch storage.

  7. A novel mechanistic spectrum underlies glaucoma-associated chromosome 6p25 copy number variation

    PubMed Central

    Chanda, Bhaskar; Asai-Coakwell, Mika; Ye, Ming; Mungall, Andrew J.; Barrow, Margaret; Dobyns, William B.; Behesti, Hourinaz; Sowden, Jane C.; Carter, Nigel P.; Walter, Michael A.; Lehmann, Ordan J.

    2008-01-01

    The factors that mediate chromosomal rearrangement remain incompletely defined. Among regions prone to structural variant formation, chromosome 6p25 is one of the few in which disease-associated segmental duplications and segmental deletions have been identified, primarily through gene dosage attributable ocular phenotypes. Using array comparative genome hybridization, we studied ten 6p25 duplication and deletion pedigrees and amplified junction fragments from each. Analysis of the breakpoint architecture revealed that all the rearrangements were non-recurrent, and in contrast to most previous examples the majority of the segmental duplications and deletions utilized coupled homologous and non-homologous recombination mechanisms. One junction fragment exhibited an unprecedented 367 bp insert derived from tandemly arranged breakpoint elements. While this accorded with a recently described replication-based mechanism, it differed from the previous example in being unassociated with template switching, and occurring in a segmental deletion. These results extend the mechanisms involved in structural variant formation, provide strong evidence that a spectrum of recombination, DNA repair and replication underlie 6p25 rearrangements, and have implications for genesis of copy number variations in other genomic regions. These findings highlight the benefits of undertaking the extensive studies necessary to characterize structural variants at the base pair level. PMID:18694899

  8. Allosteric Mutant IDH1 Inhibitors Reveal Mechanisms for IDH1 Mutant and Isoform Selectivity.

    PubMed

    Xie, Xiaoling; Baird, Daniel; Bowen, Kimberly; Capka, Vladimir; Chen, Jinyun; Chenail, Gregg; Cho, YoungShin; Dooley, Julia; Farsidjani, Ali; Fortin, Pascal; Kohls, Darcy; Kulathila, Raviraj; Lin, Fallon; McKay, Daniel; Rodrigues, Lindsey; Sage, David; Touré, B Barry; van der Plas, Simon; Wright, Kirk; Xu, Ming; Yin, Hong; Levell, Julian; Pagliarini, Raymond A

    2017-03-07

    Oncogenic IDH1 and IDH2 mutations contribute to cancer via production of R-2-hydroxyglutarate (2-HG). Here, we characterize two structurally distinct mutant- and isoform-selective IDH1 inhibitors that inhibit 2-HG production. Both bind to an allosteric pocket on IDH1, yet shape it differently, highlighting the plasticity of this site. Oncogenic IDH1(R132H) mutation destabilizes an IDH1 "regulatory segment," which otherwise restricts compound access to the allosteric pocket. Regulatory segment destabilization in wild-type IDH1 promotes inhibitor binding, suggesting that destabilization is critical for mutant selectivity. We also report crystal structures of oncogenic IDH2 mutant isoforms, highlighting the fact that the analogous segment of IDH2 is not similarly destabilized. This intrinsic stability of IDH2 may contribute to observed inhibitor IDH1 isoform selectivity. Moreover, discrete residues in the IDH1 allosteric pocket that differ from IDH2 may also guide IDH1 isoform selectivity. These data provide a deeper understanding of how IDH1 inhibitors achieve mutant and isoform selectivity.

  9. Differential Cooperation between Heterochromatin Protein HP1 Isoforms and MyoD in Myoblasts*S⃞

    PubMed Central

    Yahi, Hakima; Fritsch, Lauriane; Philipot, Ophelie; Guasconi, Valentina; Souidi, Mouloud; Robin, Philippe; Polesskaya, Anna; Losson, Regine; Harel-Bellan, Annick; Ait-Si-Ali, Slimane

    2008-01-01

    Mechanisms of transcriptional repression are important during cell differentiation. Mammalian heterochromatin protein 1 isoforms HP1α, HP1β, and HP1γ play important roles in the regulation of chromatin structure and function. We explored the possibility of different roles for the three HP1 isoforms in an integrated system, skeletal muscle terminal differentiation. In this system, terminal differentiation is initiated by the transcription factor MyoD, whose target genes remain mainly silent until myoblasts are induced to differentiate. Here we show that HP1α and HP1β isoforms, but not HP1γ, interact with MyoD in myoblasts. This interaction is direct, as shown using recombinant proteins in vitro. A gene reporter assay revealed that HP1α and HP1β, but not HP1γ, inhibit MyoD transcriptional activity, suggesting a model in which MyoD could serve as a bridge between nucleosomes and chromatin-binding proteins such as HDACs and HP1. Chromatin immunoprecipitation assays show a preferential recruitment of HP1 proteins on MyoD target genes in proliferating myoblasts. Finally, modulation of HP1 protein level impairs MyoD target gene expression and muscle terminal differentiation. Together, our data show a nonconventional interaction between HP1 and a tissue-specific transcription factor, MyoD. In addition, they strongly suggest that HP1 isoforms play important roles during muscle terminal differentiation in an isoform-dependent manner. PMID:18599480

  10. Locomotion in Lymphocytes is Altered by Differential PKC Isoform Expression

    NASA Technical Reports Server (NTRS)

    Sundaresan, A.; Risin, D.; Pellis, N. R.

    1999-01-01

    Lymphocyte locomotion is critical for proper elicitation of the immune response. Locomotion of immune cells via the interstitium is essential for optimal immune function during wound healing, inflammation and infection. There are conditions which alter lymphocyte locomotion and one of them is spaceflight. Lymphocyte locomotion is severely inhibited in true spaceflight (true microgravity) and in rotating wall vessel culture (modeled microgravity). When lymphocytes are activated prior to culture in modeled microgravity, locomotion is not inhibited and the levels are comparable to those of static cultured lymphocytes. When a phorbol ester (PMA) is used in modeled microgravity, lymphocyte locomotion is restored by 87%. This occurs regardless if PMA is added after culture in the rotating wall vessel or during culture. Inhibition of DNA synthesis also does not alter restoration of lymphocyte locomotion by PMA. PMA is a direct activator of (protein kinase C) PKC . When a calcium ionophore, ionomycin is used it does not possess any restorative properties towards locomotion either alone or collectively with PMA. Since PMA brings about restoration without help from calcium ionophores (ionomycin), it is infer-red that calcium independent PKC isoforms are involved. Changes were perceived in the protein levels of PKC 6 where levels of the protein were downregulated at 24,72 and 96 hours in untreated rotated cultures (modeled microgravity) compared to untreated static (1g) cultures. At 48 hours there is an increase in the levels of PKC & in the same experimental set up. Studies on transcriptional and translational patterns of calcium independent isoforms of PKC such as 8 and E are presented in this study.

  11. Isoform-specific monobody inhibitors of small ubiquitin-related modifiers engineered using structure-guided library design

    SciTech Connect

    Gilbreth, Ryan N.; Truong, Khue; Madu, Ikenna; Koide, Akiko; Wojcik, John B.; Li, Nan-Sheng; Piccirilli, Joseph A.; Chen, Yuan; Koide, Shohei

    2011-07-25

    Discriminating closely related molecules remains a major challenge in the engineering of binding proteins and inhibitors. Here we report the development of highly selective inhibitors of small ubiquitin-related modifier (SUMO) family proteins. SUMOylation is involved in the regulation of diverse cellular processes. Functional differences between two major SUMO isoforms in humans, SUMO1 and SUMO2/3, are thought to arise from distinct interactions mediated by each isoform with other proteins containing SUMO-interacting motifs (SIMs). However, the roles of such isoform-specific interactions are largely uncharacterized due in part to the difficulty in generating high-affinity, isoform-specific inhibitors of SUMO/SIM interactions. We first determined the crystal structure of a 'monobody,' a designed binding protein based on the fibronectin type III scaffold, bound to the yeast homolog of SUMO. This structure illustrated a mechanism by which monobodies bind to the highly conserved SIM-binding site while discriminating individual SUMO isoforms. Based on this structure, we designed a SUMO-targeted library from which we obtained monobodies that bound to the SIM-binding site of human SUMO1 with K{sub d} values of approximately 100 nM but bound to SUMO2 400 times more weakly. The monobodies inhibited SUMO1/SIM interactions and, unexpectedly, also inhibited SUMO1 conjugation. These high-affinity and isoform-specific inhibitors will enhance mechanistic and cellular investigations of SUMO biology.

  12. Myosin isoforms in female human detrusor.

    PubMed

    FitzGerald, M P; Manaves, V; Martin, A F; Shott, S; Brubaker, L

    2001-01-01

    The aim of this study was to document the relative proportions of two isoforms of myosin heavy chain in detrusor smooth muscle of women with detrusor overactivity and in asymptomatic controls. Women aged 35-65 with documented detrusor overactivity and without a history of neurologic disease, prior incontinence surgery, elevated post-void residual urine volume, or indwelling urinary catheter were eligible for the study. Full-thickness biopsies of extraperitoneal bladder dome were obtained at the time of laparotomy in six patients with documented detrusor overactivity and in a control group of eight continent patients. Biopsies were frozen in liquid nitrogen, crushed with a frozen mortar and pestle at -80 degrees C, and homogenized in buffer, and the extracts were electrophoresed on 6% polyacrylamide sodium dodecyl sulfate gels and stained with Coomassie blue. The gels were de-stained and then the protein bands were scanned with a densitometer. The mean patient age was 48 years (range, 36-59). Seven patients were Caucasian and seven patients were African American. Detrusor smooth muscle contains a mean of 34% (range, 27-43%) SM1 and 66% (range, 57-73%) SM2 isoforms. There was no difference in isoform composition when patients were compared according to urogynecologic diagnosis or according to race. In detrusor biopsies from women, approximately 34% of myosin is of the SM1 isoform and approximately 66% is of the SM2 isoform. This ratio is relatively constant in the two races studied and unchanged in women with detrusor overactivity. Animal models utilizing outlet obstruction of the bladder to provoke detrusor instability and detrusor hypertrophy are known to alter myosin isoform distribution and may not be appropriate models of detrusor instability in human females.

  13. In vitro inhibitory activities of the extract of Hibiscus sabdariffa L. (family Malvaceae) on selected cytochrome P450 isoforms.

    PubMed

    Johnson, Showande Segun; Oyelola, Fakeye Titilayo; Ari, Tolonen; Juho, Hokkanen

    2013-01-01

    Literature is scanty on the interaction potential of Hibiscus sabdariffa L., plant extract with other drugs and the affected targets. This study was conducted to investigate the cytochrome P450 (CYP) isoforms that are inhibited by the extract of Hibiscus sabdariffa L. in vitro. The inhibition towards the major drug metabolizing CYP isoforms by the plant extract were estimated in human liver microsomal incubations, by monitoring the CYP-specific model reactions through previously validated N-in-one assay method. The ethanolic extract of Hibiscus sabdariffa showed inhibitory activities against nine selected CYP isoforms: CYP1A2, CYP2A6, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A4. The concentrations of the extract which produced 50% inhibition of the CYP isoforms ranged from 306 µg/ml to 1660 µg/ml, and the degree of inhibition based on the IC50 values for each CYP isoform was in the following order: CYP1A2 > CYP2C8 > CYP2D6 > CYP2B6 > CYP2E1 > CYP2C19 > CYP3A4 > CYP2C9 > CYP2A6. Ethanolic extract of Hibiscus sabdariffa caused inhibition of CYP isoforms in vitro. These observed inhibitions may not cause clinically significant herb-drug interactions; however, caution may need to be taken in co-administering the water extract of Hibiscus sabdariffa with other drugs until clinical studies are available to further clarify these findings.

  14. Glutamine synthetase isoforms in nitrogen-fixing soybean nodules: distinct oligomeric structures and thiol-based regulation.

    PubMed

    Masalkar, Pintu D; Roberts, Daniel M

    2015-01-16

    Legume root nodule glutamine synthetase (GS) catalyzes the assimilation of ammonia produced by nitrogen fixation. Two GS isoform subtypes (GS1β and GS1γ) are present in soybean nodules. GS1γ isoforms differ from GS1β isoforms in terms of their susceptibility to reversible inhibition by intersubunit disulfide bond formation between C159 and C92 at the shared active site at subunit interfaces. Although nodule GS enzymes share 86% amino acid sequence identity, analytical ultracentrifugation experiments showed that GS1γ is a dodecamer, whereas the GS1β is a decamer. It is proposed that this difference contributes to the differential thiol sensitivity of each isoform, and that GS1γ1 may be a target of thiol-based regulation.

  15. Identification of a novel splice variant isoform of TREM-1 in human neutrophil granules1

    PubMed Central

    Baruah, Sankar; Keck, Kathy; Vrenios, Michelle; Pope, Marshall; Pearl, Merideth; Doerschug, Kevin; Klesney-Tait, Julia

    2015-01-01

    Triggering receptor expressed on myeloid cells-1 (TREM-1) is critical for inflammatory signal amplification. Humans have two forms of TREM-1: a membrane receptor (mbTREM-1), associated with the adaptor DAP12, and a soluble receptor detected at times of infection. The membrane receptor isoform acts synergistically with the TLR pathway to promote cytokine secretion and neutrophil migration while the soluble receptor functions as a counter regulatory molecule. In multiple models of sepsis, exogenous administration of soluble forms of TREM-1 attenuates inflammation and markedly improves survival. Despite intense interest in soluble TREM-1 both as a clinical predictor of survival and as a therapeutic tool, the origin of native soluble TREM-1 remains controversial. Utilizing human neutrophils, we identified a 15 kDa TREM-1 isoform in primary (azurophilic) and secondary (specific) granules. Mass spectrometric analysis, ELISA, and immunoblot confirm that the 15 kD protein is a novel splice variant of TREM-1 (TREM-1sv). Neutrophil stimulation with P. aeruginosa, LPS, or PAM(3)Cys4 resulted in degranulation and release of TREM-1sv. The addition of exogenous TREM-1sv inhibited TREM-1 receptor mediated proinflammatory cytokine production. Thus these data reveal that TREM-1 isoforms simultaneously activate and inhibit inflammation via the canonical membrane TREM-1 molecule and this newly discovered granular isoform, TREM-1sv. PMID:26561551

  16. CGX1037 is a novel PKC isoform delta selective inhibitor in platelets.

    PubMed

    Bhavanasi, Dheeraj; Kostyak, John C; Swindle, John; Kilpatrick, Laurie E; Kunapuli, Satya P

    2015-01-01

    Platelets upon activation change their shape, aggregate and secrete alpha and dense granule contents among which ADP acts as a feedback activator. Different Protein Kinase C (PKC) isoforms have specific non-redundant roles in mediating platelet responses including secretion and thrombus formation. Murine platelets lacking specific PKC isoforms have been used to evaluate the isoform specific functions. Novel PKC isoform δ has been shown to play an important role in some pathological processes. Lack of specific inhibitors for PKCδ has restricted analysis of its role in various cells. The current study was carried out to evaluate a novel small molecule PKCδ inhibitor, CGX1037 in platelets. Platelet aggregation, dense granule secretion and western blotting experiments were performed to evaluate CGX1037. In human platelets, CGX1037 inhibited PAR4-mediated phosphorylation on PKD2, a PKCδ-specific substrate. Pre-treatment of human or murine platelets with CGX1037 inhibited PAR4-mediated dense granule secretion whereas it potentiated GPVI-mediated dense granule secretion similar to the responses observed in murine platelets lacking PKCδ· Furthermore, pre-treatment of platelets from PKCδ(-/-) mice with CGX1037 had no significant additive effect on platelet responses suggesting the specificity of CGX1037. Hence, we show that CGX1037 is a selective small molecule inhibitor of PKCδ in platelets.

  17. ACA12 Is a Deregulated Isoform of Plasma Membrane Ca2+-ATPase of Arabidopsis thaliana

    PubMed Central

    Limonta, Margherita; Romanowsky, Shawn; Olivari, Claudio; Bonza, Maria Cristina; Luoni, Laura; Rosenberg, Alexa; Harper, Jeffrey F.; De Michelis, Maria Ida

    2014-01-01

    Plant auto-inhibited Ca2+-ATPases (ACA) are crucial in defining the shape of calcium transients and therefore in eliciting plant responses to various stimuli. Arabidopsis thaliana genome encodes ten ACA isoforms that can be divided into four clusters based on gene structure and sequence homology. While isoforms from clusters 1, 2 and 4 have been characterized, virtually nothing is known about members of cluster 3 (ACA12 and ACA13). Here we show that a GFP-tagged ACA12 localizes at the plasma membrane and that expression of ACA12 rescues the phenotype of partial male sterility of a null mutant of the plasma membrane isoform ACA9, thus providing genetic evidence that ACA12 is a functional plasma membrane-resident Ca2+-ATPase. By ACA12 expression in yeast and purification by CaM-affinity chromatography, we show that, unlike other ACAs, the activity of ACA12 is not stimulated by CaM. Moreover, full length ACA12 is able to rescue a yeast mutant deficient in calcium pumps. Analysis of single point ACA12 mutants suggests that ACA12 loss of auto-inhibition can be ascribed to the lack of two acidic residues - highly conserved in other ACA isoforms - localized at the cytoplasmic edge of the second and third transmembrane segments. Together, these results support a model in which the calcium pump activity of ACA12 is primarily regulated by increasing or decreasing mRNA expression and/or protein translation and degradation. PMID:24101142

  18. Comparative methylome analysis in solid tumors reveals aberrant methylation at chromosome 6p in nasopharyngeal carcinoma

    PubMed Central

    Dai, Wei; Cheung, Arthur Kwok Leung; Ko, Josephine Mun Yee; Cheng, Yue; Zheng, Hong; Ngan, Roger Kai Cheong; Ng, Wai Tong; Lee, Anne Wing Mui; Yau, Chun Chung; Lee, Victor Ho Fu; Lung, Maria Li

    2015-01-01

    Altered patterns of DNA methylation are key features of cancer. Nasopharyngeal carcinoma (NPC) has the highest incidence in Southern China. Aberrant methylation at the promoter region of tumor suppressors is frequently reported in NPC; however, genome-wide methylation changes have not been comprehensively investigated. Therefore, we systematically analyzed methylome data in 25 primary NPC tumors and nontumor counterparts using a high-throughput approach with the Illumina HumanMethylation450 BeadChip. Comparatively, we examined the methylome data of 11 types of solid tumors collected by The Cancer Genome Atlas (TCGA). In NPC, the hypermethylation pattern was more dominant than hypomethylation and the majority of de novo methylated loci were within or close to CpG islands in tumors. The comparative methylome analysis reveals hypermethylation at chromosome 6p21.3 frequently occurred in NPC (false discovery rate; FDR=1.33 × 10−9), but was less obvious in other types of solid tumors except for prostate and Epstein–Barr virus (EBV)-positive gastric cancer (FDR<10−3). Bisulfite pyrosequencing results further confirmed the aberrant methylation at 6p in an additional patient cohort. Evident enrichment of the repressive mark H3K27me3 and active mark H3K4me3 derived from human embryonic stem cells were found at these regions, indicating both DNA methylation and histone modification function together, leading to epigenetic deregulation in NPC. Our study highlights the importance of epigenetic deregulation in NPC. Polycomb Complex 2 (PRC2), responsible for H3K27 trimethylation, is a promising therapeutic target. A key genomic region on 6p with aberrant methylation was identified. This region contains several important genes having potential use as biomarkers for NPC detection. PMID:25924914

  19. Metallicity of Ca2Cu6P5 with single and double copper-pnictide layers

    DOE PAGES

    Li, Li; Parker, David; Chi, Miaofang; ...

    2016-02-16

    We report thermodynamic and transport properties, and also theoretical calculations, for Cu-based compound Ca2Cu6P5 and compare with CaCu2-δP2. Both materials have layers of edge-sharing copper pnictide tetrahedral CuP4, similar to Fe–As and Fe–Se layers (with FeAs4, FeSe4) in the iron-based superconductors. Despite the presence of this similar transition-metal pnictide layer, we find that both Ca2Cu6P5 and CaCu2-δP2 have temperature-independent magnetic susceptibility and show metallic behavior with no evidence of either magnetic ordering or superconductivity down to 1.8 K CaCu2-δP2 is slightly off-stoichiometric, with δ = 0.14. Theoretical calculations suggest that unlike Fe 3d-based magnetic materials with a large density ofmore » states (DOS) at the Fermi surface, Cu have comparatively low DOS, with the majority of the 3d spectral weight located well below Fermi level. The room-temperature resistivity value of Ca2Cu6P5 is only 9 μΩ-cm, due to a substantial plasma frequency and an inferred electron-phonon coupling λ of 0.073 (significantly smaller than that of metallic Cu). Also, microscopy result shows that Cu–Cu distance along the c-axis within the double layers can be very short (2.5 Å), even shorter than metallic elemental copper bond (2.56 Å). The value of dρ/dT for CaCu2-δP2 at 300 K is approximately three times larger than in Ca2Cu6P5, which suggests the likelihood of stronger electron-phonon coupling. Lastly, this study shows that the details of Cu–P layers and bonding are important for their transport characteristics. In addition, it emphasizes the remarkable character of the DOS of ‘122’ iron-based materials, despite much structural similarities.« less

  20. Structure and characterization of AAT-1 isoforms.

    PubMed

    Matsuda, Eiko; Ishizaki, Ray; Taira, Takahiro; Iguchi-Ariga, Sanae M M; Ariga, Hiroyoshi

    2005-05-01

    A novel protein, AAT-1, was identified as a AMY-1-binding protein and three splicing variants of AAT-1, AAT-1alpha, -beta and -gamma were identified. The function of AAT-1 is thought to be related to spermatogenesis. In this study, we further identified other splicing isoforms of AAT-1, AAT-1L, AAT-1M and AAT-1S, consisting of 767, 603 and 252 amino acids, respectively. These isoforms were found to use a promoter different from that used by AAT-1alpha, -beta and -gamma in the aat-1 gene, which contains 20 exons. Only 60 amino acids in the C-terminal portion of AAT-1 derived from exons 15-17 are common among AAT-1L, AAT-1M, AAT-1S and AAT-1alpha. While AAT-1alpha is specifically expressed in the testis, AAT-1L, AAT-1M, AAT-1S were found to be differentially expressed in human tissues. All of the isoforms of AAT-1 were found to bind to and colocalized with AMY-1 in human cells. While AAT-1L and AAT-1M were found to be localized diffusely in the cytoplasm, AAT-1S, like AAT-1alpha, was found to be localized in the mitochondria-like structure, suggesting different roles of AAT-1 isoforms in cells.

  1. Functional Analysis of the Short Isoform of Orf Virus Protein OV20.0

    PubMed Central

    Tseng, Yeu-Yang; Lin, Fong-Yuan; Cheng, Sun-Fang; Chulakasian, Songkhla; Chou, Chia-Chi; Liu, Ya-Fen; Chang, Wei-Shan; Wong, Min-Liang

    2015-01-01

    ABSTRACT Orf virus (ORFV) OV20.0L is an ortholog of vaccinia virus (VACV) gene E3L. The function of VACV E3 protein as a virulence factor is well studied, but OV20.0 has received less attention. Here we show that like VACV E3L, OV20.0L encodes two proteins, a full-length protein and a shorter form (sh20). The shorter sh20 is an N-terminally truncated OV20.0 isoform generated when a downstream AUG codon is used for initiating translation. These isoforms differed in cellular localization, with full-length OV20.0 and sh20 found throughout the cell and predominantly in the cytoplasm, respectively. Nonetheless, both OV20.0 isoforms were able to bind double-stranded RNA (dsRNA)-activated protein kinase (PKR) and dsRNA. Moreover, both isoforms strongly inhibited PKR activation as shown by decreased phosphorylation of the translation initiation factor eIF2α subunit and protection of Sindbis virus infection against the activity of interferon (IFN). In spite of this apparent conservation of function in vitro, a recombinant ORFV that was able to express only the sh20 isoform was attenuated in a mouse model. IMPORTANCE The OV20.0 protein of orf virus (ORFV) has two isoforms and contributes to virulence, but the roles of the two forms are not known. This study shows that the shorter isoform (sh20) arises due to use of a downstream initiation codon and is amino-terminally truncated. The sh20 form also differs in expression kinetics and cellular localization from full-length OV20.0. Similar to the full-length isoform, sh20 is able to bind dsRNA and PKR, inactivate PKR, and thus act as an antagonist of the interferon response in vitro. In vivo, however, wild-type OV20.0 could not be replaced with sh20 alone without a loss of virulence, suggesting that the functions of the isoforms are not simply redundant. PMID:25694596

  2. Absolute quantitation of protein posttranslational modification isoform.

    PubMed

    Yang, Zhu; Li, Ning

    2015-01-01

    Mass spectrometry has been widely applied in characterization and quantification of proteins from complex biological samples. Because the numbers of absolute amounts of proteins are needed in construction of mathematical models for molecular systems of various biological phenotypes and phenomena, a number of quantitative proteomic methods have been adopted to measure absolute quantities of proteins using mass spectrometry. The liquid chromatography-tandem mass spectrometry (LC-MS/MS) coupled with internal peptide standards, i.e., the stable isotope-coded peptide dilution series, which was originated from the field of analytical chemistry, becomes a widely applied method in absolute quantitative proteomics research. This approach provides more and more absolute protein quantitation results of high confidence. As quantitative study of posttranslational modification (PTM) that modulates the biological activity of proteins is crucial for biological science and each isoform may contribute a unique biological function, degradation, and/or subcellular location, the absolute quantitation of protein PTM isoforms has become more relevant to its biological significance. In order to obtain the absolute cellular amount of a PTM isoform of a protein accurately, impacts of protein fractionation, protein enrichment, and proteolytic digestion yield should be taken into consideration and those effects before differentially stable isotope-coded PTM peptide standards are spiked into sample peptides have to be corrected. Assisted with stable isotope-labeled peptide standards, the absolute quantitation of isoforms of posttranslationally modified protein (AQUIP) method takes all these factors into account and determines the absolute amount of a protein PTM isoform from the absolute amount of the protein of interest and the PTM occupancy at the site of the protein. The absolute amount of the protein of interest is inferred by quantifying both the absolute amounts of a few PTM

  3. Tunable protein synthesis by transcript isoforms in human cells.

    PubMed

    Floor, Stephen N; Doudna, Jennifer A

    2016-01-06

    Eukaryotic genes generate multiple RNA transcript isoforms though alternative transcription, splicing, and polyadenylation. However, the relationship between human transcript diversity and protein production is complex as each isoform can be translated differently. We fractionated a polysome profile and reconstructed transcript isoforms from each fraction, which we term Transcript Isoforms in Polysomes sequencing (TrIP-seq). Analysis of these data revealed regulatory features that control ribosome occupancy and translational output of each transcript isoform. We extracted a panel of 5' and 3' untranslated regions that control protein production from an unrelated gene in cells over a 100-fold range. Select 5' untranslated regions exert robust translational control between cell lines, while 3' untranslated regions can confer cell type-specific expression. These results expose the large dynamic range of transcript-isoform-specific translational control, identify isoform-specific sequences that control protein output in human cells, and demonstrate that transcript isoform diversity must be considered when relating RNA and protein levels.

  4. Juvenile myoclonic epilepsy: linkage to chromosome 6p12 in Mexico families.

    PubMed

    Bai, Dongsheng; Alonso, Maria E; Medina, Marco T; Bailey, Julia N; Morita, Ryoji; Cordova, Sergio; Rasmussen, Astrid; Ramos-Peek, Jaime; Ochoa, Adriana; Jara, Aurelio; Donnadieu, Francisco R; Cadena, Gilbert; Yamakawa, Kazuhiro; Delgado-Escueta, Antonio V

    2002-12-01

    Juvenile myoclonic epilepsy is a common subtype of idiopathic epilepsy accounting for 4-11% of all epilepsies. We reported previously significant evidence of linkage between chromosome 6p12-11 microsatellites and the clinical epilepsy and EEG traits of JME families from Belize and Los Angeles. To narrow the JME region, we ascertained and genotyped 31 new JME families from Mexico using a later generation of Généthon microsatellites. Two point linkage analyses obtained significant Z(max) values of 3.70 for D6S1573 and 2.65 for D6S1714 at theta(m = f) = 0.10, and 3.49 for D6S465, 2.11 for D6S1960 at theta(m = f) = 0.05 assuming autosomal dominant inheritance with 70% age-dependent penetrance. Multipoint LOD score curve peaked at 4.21 for D6S1573. Haplotype and recombination analysis reduced the JME region to 3.5 cM flanked by D6S272 and D6S1573. These results provide confirmatory evidence that a major susceptibility gene for JME exists in chromosome 6p12 in Spanish-Amerinds of Mexico.

  5. Emergence of Unusual G6P[6] Rotaviruses in Children, Burkina Faso, 2009–2010

    PubMed Central

    Nitiema, Leon W.; Sharma, Sumit; Ouermi, Djeneba; Traore, Alfred S.; Simpore, Jacques; Svensson, Lennart

    2012-01-01

    To obtain more information about rotavirus (ROTAV) genotypes in Burkina Faso, we characterized 100 ROTAVs isolated from fecal samples of children with acute gastroenteritis in the capital city of Ouagadougou, during December 2009–March 2010. Of note, 13% of the ROTAV-positive samples, including those with mixed infections, were positive for the unusual G6 genotype ROTAV strain. The genotypes identified were G9P[8], G6P[6], G1P[6], G3P[6], G1P[8], and G2P[4]. G9P[8] subgroup (SG)II strains dominated during the beginning of the ROTAV season, but later in the season, other G types associated with P[6] and SGI specificity emerged. This emergence was related to a shift in the overall age of infected children; ROTAV SGII infected younger children and induced more severe symptoms. The finding of a high incidence of G6P[6] strains highlights the need for long-term surveillance of ROTAV strains in Burkina Faso, especially when ROTAV vaccination is being considered in several African countries. PMID:22469076

  6. Virulence of the Fungal Pathogen Candida albicans Requires the Five Isoforms of Protein Mannosyltransferases

    PubMed Central

    Rouabhia, Mahmoud; Schaller, Martin; Corbucci, Cristina; Vecchiarelli, Anna; Prill, Stephan K.-H.; Giasson, Luc; Ernst, Joachim F.

    2005-01-01

    The PMT gene family in Candida albicans encodes five isoforms of protein mannosyltransferases (Pmt proteins Pmt1p, Pmt2p, Pmt4p, Pmt5p, and Pmt6p) that initiate O mannosylation of secretory proteins. We compared virulence characteristics of pmt mutants in two complex, three-dimensional models of localized candidiasis, using reconstituted human epithelium (RHE) and engineered human oral mucosa (EHOM); in addition, mutants were tested in a mouse model of hematogenously disseminated candidiasis (HDC). All pmt mutants showed attenuated virulence in the HDC model and at least one model of localized candidiasis. The pmt5 mutant, which lacks in vitro growth phenotypes, was less virulent in the EHOM and HDC assays but had no consistent phenotype in the RHE assay. In contrast, the pmt4 and pmt6 mutants were less virulent in the RHE and HDC assays but not in the EHOM assay. The results stress the contribution of all Pmt isoforms to the virulence of C. albicans and suggest that the importance of individual Pmt isoforms may differ in specific host niches. We propose that Pmt proteins may be suitable targets for future novel classes of antifungal agents. PMID:16040968

  7. Virulence of the fungal pathogen Candida albicans requires the five isoforms of protein mannosyltransferases.

    PubMed

    Rouabhia, Mahmoud; Schaller, Martin; Corbucci, Cristina; Vecchiarelli, Anna; Prill, Stephan K-H; Giasson, Luc; Ernst, Joachim F

    2005-08-01

    The PMT gene family in Candida albicans encodes five isoforms of protein mannosyltransferases (Pmt proteins Pmt1p, Pmt2p, Pmt4p, Pmt5p, and Pmt6p) that initiate O mannosylation of secretory proteins. We compared virulence characteristics of pmt mutants in two complex, three-dimensional models of localized candidiasis, using reconstituted human epithelium (RHE) and engineered human oral mucosa (EHOM); in addition, mutants were tested in a mouse model of hematogenously disseminated candidiasis (HDC). All pmt mutants showed attenuated virulence in the HDC model and at least one model of localized candidiasis. The pmt5 mutant, which lacks in vitro growth phenotypes, was less virulent in the EHOM and HDC assays but had no consistent phenotype in the RHE assay. In contrast, the pmt4 and pmt6 mutants were less virulent in the RHE and HDC assays but not in the EHOM assay. The results stress the contribution of all Pmt isoforms to the virulence of C. albicans and suggest that the importance of individual Pmt isoforms may differ in specific host niches. We propose that Pmt proteins may be suitable targets for future novel classes of antifungal agents.

  8. Isoform-specific monoubiquitination, endocytosis, and degradation of alternatively spliced ErbB4 isoforms.

    PubMed

    Sundvall, Maria; Korhonen, Anna; Paatero, Ilkka; Gaudio, Eugenio; Melino, Gerry; Croce, Carlo M; Aqeilan, Rami I; Elenius, Klaus

    2008-03-18

    Endocytosis and subsequent lysosomal degradation serve as a well characterized mechanism to fine-tune and down-regulate EGFR signaling. However, other members of the EGFR/ErbB receptor family have been reported to be endocytosis-impaired. Here we demonstrate that endocytosis of ErbB4 is regulated in an isoform-specific manner: CYT-1 isoforms were efficiently endocytosed whereas CYT-2 isoforms were endocytosis-impaired. CYT-1 isoforms in endocytic vesicles colocalized with Rab5 and Rab7 indicating trafficking via early endosomes to late endosomal/lysosomal structures. A PPXY motif within the CYT-1-specific sequence that lacks from CYT-2 was necessary both for ubiquitination and endocytosis of CYT-1 isoforms and provided a binding site for a WW domain-containing ubiquitin ligase Itch. Itch catalyzed ubiquitination of ErbB4 CYT-1, promoted its localization into intracellular vesicles, and stimulated degradation of ErbB4 CYT-1. Dominant negative Itch suppressed ErbB4 CYT-1 endocytosis and degradation. These data indicate that ErbB4 isoforms differ in endocytosis and degradation by a mechanism mediated by CYT-1-specific PPXY motif interacting with a WW domain-containing E3 ubiquitin ligase.

  9. Synthesis and Pharmacological Evaluation of 4-Iminothiazolidinones for Inhibition of PI3 Kinase

    PubMed Central

    Pinson, Jo-Anne; Schmidt-Kittler, Oleg; Frazzetto, Mark; Zheng, Zhaohua; Jennings, Ian G.; Kinzler, Kenneth W.; Vogelstein, Bert; Chalmers, David K.; Thompson, Philip E.

    2012-01-01

    The thiazolidinedione, compound 1, has previously shown pan-inhibition of the phosphoinositide 3-kinase (PI3K) class I isoforms. We hypothesized the derivatization of the thiazolidinedione core of compound 1 could introduce isoform selectivity. We report the synthesis, characterization, and inhibitory activity of a novel series of 4-iminothiazolidin-2-ones for inhibition of the class I PI3K isoforms. Their synthesis was successfully achieved by multiple pathways described in this paper. Initial in vitro data of 28 analogues demonstrated poor inhibition of all class I PI3K isoforms. However, we identified an alternate target, the phosphodiesterases, and present preliminary screening results showing improved inhibitory activity. PMID:23997244

  10. Mesenchymal Stromal Cells for Sphincter Regeneration: Role of Laminin Isoforms upon Myogenic Differentiation

    PubMed Central

    Seeger, Tanja; Hart, Melanie; Patarroyo, Manuel; Rolauffs, Bernd; Aicher, Wilhelm K.; Klein, Gerd

    2015-01-01

    Multipotent mesenchymal stromal cells (MSCs) are well known for their tri-lineage potential and ability to differentiate in vitro into osteogenic, chondrogenic or adipogenic lineages. By selecting appropriate conditions MSCs can also be differentiated in vitro into the myogenic lineage and are therefore a promising option for cell-based regeneration of muscle tissue such as an aged or damaged sphincter muscle. For the differentiation into the myogenic lineage there is still a need to evaluate the effects of extracellular matrix proteins such as laminins (LM) which are crucial for different stem cell types and for normal muscle function. The laminin family consists of 16 functionally different isoforms with LM-211 being the most abundant isoform of adult muscle tissues. In the sphincter tissue a strong expression of the isoforms LM-211/221, LM-411/421 and LM-511/521 can be detected in the different cell layers. Bone marrow-derived MSCs in culture, however, mainly express the isoforms LM-411 and LM-511, but not LM-211. Even after myogenic differentiation, LM-211 can hardly be detected. All laminin isoforms tested (LM-211, LM-411, LM-511 and LM-521) showed a significant inhibition of the proliferation of undifferentiated MSCs but, with the exception of LM-521, they had no influence on the proliferation of MSCs cultivated in myogenic medium. The strongest cellular adhesion of MSCs was to LM-511 and LM-521, whereas LM-211 was only a weakly-adhesive substrate for MSCs. Myogenic differentiation of MSCs even reduced the interaction with LM-211, but it did not affect the interaction with LM-511 and LM-521. Since during normal myogenesis the latter two isoforms are the major laminins surrounding developing myogenic progenitors, α5 chain-containing laminins are recommended for further improvements of myogenic differentiation protocols of MSCs into smooth muscle cells. PMID:26406476

  11. Cell death or survival promoted by alternative isoforms of ErbB4.

    PubMed

    Sundvall, Maria; Veikkolainen, Ville; Kurppa, Kari; Salah, Zaidoun; Tvorogov, Denis; van Zoelen, E Joop; Aqeilan, Rami; Elenius, Klaus

    2010-12-01

    The significance of ErbB4 in tumor biology is poorly understood. The ERBB4 gene is alternatively spliced producing juxtamembrane (JM-a and JM-b) and cytoplasmic (CYT-1 and CYT-2) isoforms. Here, signaling via the two alternative ErbB4 JM isoforms (JM-a CYT-2 and JM-b CYT-2) was compared. Fibroblasts expressing ErbB4 JM-a demonstrated enhanced ErbB4 autophosphorylation, growth, and survival. In contrast, cells overexpressing ErbB4 JM-b underwent starvation-induced death. Both pro- and antisurvival responses to the two ErbB4 isoforms were sensitive to an ErbB kinase inhibitor. Platelet-derived growth factor receptor-alpha (PDGFRA) was identified as an ErbB4 target gene that was differentially regulated by the two ErbB4 isoforms. The soluble intracellular domain of ErbB4, released from the JM-a but not from the JM-b isoform, associated with the transcription factor AP-2 and promoted its potential to enhance PDGFRA transcription. Survival of cells expressing JM-a was suppressed by targeting either PDGFR-α or AP-2, whereas cells expressing JM-b were rescued from cell death by the PDGFR-α agonist, PDGF-BB. These findings indicate that two alternative ErbB4 isoforms may promote antagonistic cellular responses and suggest that pharmacological inhibition of ErbB4 kinase activity may lead to either suppression or promotion of cellular growth.

  12. Cell Death or Survival Promoted by Alternative Isoforms of ErbB4

    PubMed Central

    Sundvall, Maria; Veikkolainen, Ville; Kurppa, Kari; Salah, Zaidoun; Tvorogov, Denis; van Zoelen, E. Joop; Aqeilan, Rami

    2010-01-01

    The significance of ErbB4 in tumor biology is poorly understood. The ERBB4 gene is alternatively spliced producing juxtamembrane (JM-a and JM-b) and cytoplasmic (CYT-1 and CYT-2) isoforms. Here, signaling via the two alternative ErbB4 JM isoforms (JM-a CYT-2 and JM-b CYT-2) was compared. Fibroblasts expressing ErbB4 JM-a demonstrated enhanced ErbB4 autophosphorylation, growth, and survival. In contrast, cells overexpressing ErbB4 JM-b underwent starvation-induced death. Both pro- and antisurvival responses to the two ErbB4 isoforms were sensitive to an ErbB kinase inhibitor. Platelet-derived growth factor receptor-alpha (PDGFRA) was identified as an ErbB4 target gene that was differentially regulated by the two ErbB4 isoforms. The soluble intracellular domain of ErbB4, released from the JM-a but not from the JM-b isoform, associated with the transcription factor AP-2 and promoted its potential to enhance PDGFRA transcription. Survival of cells expressing JM-a was suppressed by targeting either PDGFR-α or AP-2, whereas cells expressing JM-b were rescued from cell death by the PDGFR-α agonist, PDGF-BB. These findings indicate that two alternative ErbB4 isoforms may promote antagonistic cellular responses and suggest that pharmacological inhibition of ErbB4 kinase activity may lead to either suppression or promotion of cellular growth. PMID:20943952

  13. Mesenchymal Stromal Cells for Sphincter Regeneration: Role of Laminin Isoforms upon Myogenic Differentiation.

    PubMed

    Seeger, Tanja; Hart, Melanie; Patarroyo, Manuel; Rolauffs, Bernd; Aicher, Wilhelm K; Klein, Gerd

    2015-01-01

    Multipotent mesenchymal stromal cells (MSCs) are well known for their tri-lineage potential and ability to differentiate in vitro into osteogenic, chondrogenic or adipogenic lineages. By selecting appropriate conditions MSCs can also be differentiated in vitro into the myogenic lineage and are therefore a promising option for cell-based regeneration of muscle tissue such as an aged or damaged sphincter muscle. For the differentiation into the myogenic lineage there is still a need to evaluate the effects of extracellular matrix proteins such as laminins (LM) which are crucial for different stem cell types and for normal muscle function. The laminin family consists of 16 functionally different isoforms with LM-211 being the most abundant isoform of adult muscle tissues. In the sphincter tissue a strong expression of the isoforms LM-211/221, LM-411/421 and LM-511/521 can be detected in the different cell layers. Bone marrow-derived MSCs in culture, however, mainly express the isoforms LM-411 and LM-511, but not LM-211. Even after myogenic differentiation, LM-211 can hardly be detected. All laminin isoforms tested (LM-211, LM-411, LM-511 and LM-521) showed a significant inhibition of the proliferation of undifferentiated MSCs but, with the exception of LM-521, they had no influence on the proliferation of MSCs cultivated in myogenic medium. The strongest cellular adhesion of MSCs was to LM-511 and LM-521, whereas LM-211 was only a weakly-adhesive substrate for MSCs. Myogenic differentiation of MSCs even reduced the interaction with LM-211, but it did not affect the interaction with LM-511 and LM-521. Since during normal myogenesis the latter two isoforms are the major laminins surrounding developing myogenic progenitors, α5 chain-containing laminins are recommended for further improvements of myogenic differentiation protocols of MSCs into smooth muscle cells.

  14. A diacylglycerol kinase inhibitor, R59022, stimulates glucose transport through a MKK3/6-p38 signaling pathway in skeletal muscle cells.

    PubMed

    Takahashi, Nobuhiko; Nagamine, Miho; Tanno, Satoshi; Motomura, Wataru; Kohgo, Yutaka; Okumura, Toshikatsu

    2007-08-17

    Diacylglycerol kinase (DGK) is one of lipid-regulating enzymes, catalyzes phosphorylation of diacylglycerol to phosphatidic acid. Because skeletal muscle, a major insulin-target organ for glucose disposal, expresses DGK, we investigated in the present study a role of DGK on glucose transport in skeletal muscle cells. PCR study showed that C2C12 myotubes expressed DGKalpha, delta, epsilon, zeta, or theta isoform mRNA. R59022, a specific inhibitor of DGK, significantly increased glucose transport, p38 and MKK3/6 activation in C2C12 myotubes. The R59022-induced glucose transport was blocked by SB203580, a specific p38 inhibitor. In contrast, R59022 failed to stimulate both possible known mechanisms to enhance glucose transport, an IRS1-PI3K-Akt pathway, muscle contraction signaling or GLUT1 and 4 expression. All these results suggest that DGK may play a role in glucose transport in the skeletal muscle cells through modulating a MKK3/6-p38 signaling pathway.

  15. Effects of eugenol on T-type Ca2+ channel isoforms.

    PubMed

    Seo, Haengsoo; Li, Hai Ying; Perez-Reyes, Edward; Lee, Jung-Ha

    2013-11-01

    Eugenol has been used as an analgesic in dentistry. Previous studies have demonstrated that voltage-gated Na(+) channels and high-voltage-activated Ca(2+) channels expressed in trigeminal ganglion (TG) neurons sensing dental pain are molecular targets of eugenol for its analgesic effects. However, it has not been investigated whether eugenol can affect T-type Ca(2+) channels, which are known to be detected in the afferent neurons. In this report, we investigate how eugenol can influence cloned T-type channel isoforms expressed in HEK293 cells, using whole-cell patch clamp. Application of eugenol inhibited Cav3.1, Cav3.2, and Cav3.3 currents in a concentration-dependent manner with IC50 values of 463, 486, and 708 μM, respectively. Eugenol was found to negatively shift the steady-state inactivation curves of the T-type channel isoforms, but it did not shift their activation curves. In addition, eugenol had little effect on the current kinetics of Cav3.1 and Cav3.2, but it accelerated the inactivation kinetics of Cav3.3 currents. Reduction of channel availability enhanced eugenol inhibition sensitivity for Cav3.1 and Cav3.2, but not for Cav3.3. Moreover, eugenol inhibition of T-type channel isoforms was found to be use dependent. Finally, we show that the T-type currents recorded from rat TG neurons were inhibited by eugenol with a similar potency to Cav3.1 and Cav3.2 isoforms. Taken together, our findings suggest that T-type Ca(2+) channels are additional molecular targets for the pain-relieving effects of eugenol.

  16. A gene for autosomal dominant congenital nystagmus localizes to 6p12

    SciTech Connect

    Kerrison, J.B.; Arnould, V.J.; Koenekoop, R.K.

    1996-05-01

    Congenital nystagmus is an idiopathic disorder characterized by bilateral ocular oscillations usually manifest during infancy. Vision is typically decreased due to slippage of images across the fovea. As such, visual acuity correlates with nystagmus intensity, which is the amplitude and frequency of eye movements at a given position of gaze. X-linked, autosomal dominant, and autosomal recessive pedigrees have been described, but no mapping studies have been published. We recently described a large pedigree with autosomal dominant congenital nystagmus. A genome-wide search resulted in six markers on 6p linked by two-point analysis at {theta} = 0 (D6S459, D6S452, D6S465, FTHP1, D6S257, D6S430). Haplotype analysis localizes the gene for autosomal dominant congenital motor mystagmus to an 18-cM region between D6S271 and D6S455. 16 refs., 1 fig., 1 tab.

  17. Fine genetic mapping of a gene for autosomal recessive retinitis pigmentosa on chromosome 6p21

    SciTech Connect

    Shugart, Yin Y.; Banerjee, P.; Knowles, J.A.

    1995-08-01

    The inherited retinal degenerations known as retinitis pigmentosa (RP) can be caused by mutations at many different loci and can be inherited as an autosomal recessive, autosomal dominant, or X-linked recessive trait. Two forms of autosomal recessive (arRP) have been reported to cosegregate with mutations in the rhodopsin gene and the beta-subunit of rod phosphodiesterase on chromosome 4p. Genetic linkage has been reported on chromosomes 6p and 1q. In a large Dominican family, we reported an arRp gene near the region of the peripherin/RDS gene. Four recombinations were detected between the disease locus and an intragenic marker derived from peripherin/RDS. 26 refs., 2 figs., 1 tab.

  18. Fluorescence origin of 6,P-toluidinyl-naphthalene-2-sulfonate (TNS) bound to proteins.

    PubMed

    Albani, J-R

    2009-05-01

    6,P-toluidinylnaphthalene-2-sulfonate (TNS) is a highly fluorescent molecule when dissolved in a low polarity medium or when bound to proteins. The aim of the present work is to explain origin of this fluorescence, to find out how the medium (solvent, protein matrix) affects fluorescence observables such as lifetimes and spectra and finally to put into evidence possible relation that exists between these observables and fluorophore structure. To achieve our goal we performed studies on TNS dissolved in ethanol, at high concentrations in water (aggregated form) and bound to proteins. Our experiments allowed us to find out that TNS in the three environments has different structures. Presence of three lifetimes observed in proteins and in water instead of one lifetime found in ethanol can be assigned to the high contact between TNS molecules. Our results are discussed in terms of solvent polarity and interaction within fluorophore molecules bound to proteins.

  19. Multiple isoforms of Arabidopsis casein kinase I combine conserved catalytic domains with variable carboxyl-terminal extensions.

    PubMed Central

    Klimczak, L J; Farini, D; Lin, C; Ponti, D; Cashmore, A R; Giuliano, G

    1995-01-01

    Three cDNA clones encoding isoforms of casein kinase I (CKI) were isolated from Arabidopsis thaliana. One full-length clone, designated CKI1, contained an open reading frame of 1371 bp encoding a protein of 51,949 D with an isoelectric point of 9.7. In addition to the highly conserved catalytic domain (of about 300 amino acids), the Arabidopsis CKI isoforms contain 150 to 180 amino acid carboxyl-terminal extensions, which show among themselves a lower level of sequence conservation. These extensions do not show any sequence similarity to nonplant CKI isoforms, such as rat testis CKI delta, which is their closest isolated homolog, or to yeast CKI isoforms. Three additional isoforms of Arabidopsis CKI were found in the data bases of expressed sequence tags and/or were isolated serendipitously in nonspecific screening procedures by others. One of them also shows a carboxyl-terminal extension, but of only 80 amino acids. Casein kinase activity was detected in the soluble fraction of Escherichia coli strains expressing the CKI1 protein. This activity showed the crucial properties of CKI, including the ability to phosphorylate the D4 peptide, a specific substrate of CKI, and inhibition by N-(2-aminoethyl)-5-chloroisoquinoline-8-sulfonamide, a specific CKI inhibitor. Like several recombinant CKI isoforms from yeast, CKI1 was able to phosphorylate tyrosine-containing acidic polymers. PMID:7480353

  20. Isoform-specific proteasomal degradation of Rbfox3 during chicken embryonic development

    SciTech Connect

    Kim, Kee K.; Adelstein, Robert S.; Kawamoto, Sachiyo

    2014-08-08

    Highlights: • Protein stability of Rbfox3 splice isoforms is differentially regulated. • Rbfox3-d31, an Rbfox3 isoform lacking the RRM, is highly susceptible to degradation. • The protein stability of Rbfox3-d31 is regulated by the ubiquitin–proteasome pathway. • Rbfox3-d31 inhibits the nuclear localization of Rbfox2. • Rbfox3-d31 inhibits the splicing activity of Rbfox2. - Abstract: Rbfox3, a neuron-specific RNA-binding protein, plays an important role in neuronal differentiation during development. An isoform Rbfox3-d31, which excludes the 93-nucleotide cassette exon within the RNA recognition motif of chicken Rbfox3, has been previously identified. However, the cellular functions of Rbfox3-d31 remain largely unknown. Here we find that Rbfox3-d31 mRNA is highly expressed during the early developmental stages of the chicken embryo, while Rbfox3-d31 protein is barely detected during the same stage due to its rapid degradation mediated by the ubiquitin–proteasome pathway. Importantly, this degradation is specific to the Rbfox3-d31 isoform and it does not occur with full-length Rbfox3. Furthermore, suppression of Rbfox3-d31 protein degradation with the proteasome inhibitor MG132 attenuates the splicing activity of another Rbfox family member Rbfox2 by altering the subcellular localization of Rbfox2. These results suggest that Rbfox3-d31 functions as a repressor for the splicing activity of the Rbfox family and its protein level is regulated in an isoform-specific manner in vivo.

  1. Juvenile myoclonic epilepsy in chromosome 6p12-p11: Locus heterogeneity and recombinations

    SciTech Connect

    Liu, A.W.; Delgado-Escueta, A.V.; Serratosa, J.M.

    1996-06-14

    We recently analyzed under homogeneity a large pedigree from Belize with classic juvenile myoclonic epilepsy (JME). After a genome-wide search with 146 microsatellites, we obtained significant linkage between chromosome 6p markers, D6S257 and D6S272, and both convulsive and EEG traits of JME. Recombinations in two affected members defined a 40 cM JME region flanked by D6S313 and D6S258. In the present communication, we explored if the same chromosome 6p11 microsatellites also have a role in JME mixed with pyknoleptic absences. We allowed for heterogeneity during linkage analyses. We tested for heterogeneity by the admixture test and looked for more recombinations. D6S272, D6S466, D6S294, and D6S257 were significantly linked (Z{sub max} > 3.5) to the clinical and EEG traits of 22 families, assuming autosomal dominant inheritance with 70% penetrance. Pairwise Z{sub max} were 4.230 for D6S294 ({theta}{sub m=f} at 0.133) and 4.442 for D6S466 ({theta}{sub m=f} at 0.111). Admixture test (H{sub 2} vs. H{sub 1}) was significant (P = 0.0234 for D6S294 and 0.0128 for D6S272) supporting the hypotheses of linkage with heterogeneity. Estimated proportion of linked families, {alpha}, was 0.50 (95% confidence interval 0.05-0.99) for D6S294 and D6S272. Multipoint analyses and recombinations in three new families narrowed the JME locus to a 7 cM interval flanked by D6S272 and D6S257. 44 refs., 3 figs., 4 tabs.

  2. Rotavirus in diarrheal children in rural Burkina Faso: high prevalence of genotype G6P[6].

    PubMed

    Nordgren, Johan; Bonkoungou, Isidore Juste O; Nitiema, Leon W; Sharma, Sumit; Ouermi, Djeneba; Simpore, Jacques; Barro, Nicolas; Svensson, Lennart

    2012-12-01

    Group A rotavirus (RVA) is the most common cause of severe gastroenteritis in young children globally, and responsible for a significant number of deaths in African countries. While vaccines are available, trials have shown a lesser efficacy in Africa. One of the reasons could be the prevalence and/or emergence of unusual or novel RVA strains, as many strains detected in African countries remain uncharacterized. In this study, we characterized RVA positive specimens from two remote rural areas in Burkina Faso, West Africa. In total 56 RVA positive specimens were subgrouped by their VP6 gene, and G-and P typed by PCR and/or sequencing of the VP7 and VP4 genes, respectively. Notably, we found a high prevalence of the unusual G6P[6]SGI strains (23%). It was the second most common constellation after G9P[8]SGII (32%); and followed by G1P[8]SGII (20%) and G2P[4]SGI (9%). We also detected a G8P[6]SGI strain, for the first time in Burkina Faso. The intra-genetic diversity was high for the VP4 gene with two subclusters within the P[8] genotype and three subclusters within the P[6] genotype which were each associated with a specific G-type, thereby suggesting a genetic linkage. The G6P[6]SGI and other SGI RVA strains infected younger children as compared to SGII strains (p<0.05). To conclude, in this study we observed the emergence of unusual RVA strains and high genetic diversity of RVA in remote rural areas of Burkina Faso. The results highlight the complexity of RVA epidemiology which may have implication for the introduction of rotavirus vaccines currently being evaluated in many African countries.

  3. Rabbit colony infected with a bovine-like G6P[11] rotavirus strain.

    PubMed

    Schoondermark-van de Ven, Esther; Van Ranst, Marc; de Bruin, Wieke; van den Hurk, Patrick; Zeller, Mark; Matthijnssens, Jelle; Heylen, Elisabeth

    2013-09-27

    Group A rotaviruses (RVAs) are the main etiological agent of infantile diarrhea in both humans and animals worldwide. A limited number of studies have investigated the molecular characteristics of RVA strains in stool specimens of rabbits, with only a few lapine RVA strains isolated and (partially) characterized to date. The most common G/P-genotype combinations found in rabbits are G3P[14] and G3P[22]. In this study a RVA strain was isolated from the small intestine of a 9-week-old rabbit from an infected laboratory rabbit colony. The RVA strain RVA/Rabbit-tc/NLD/K1130027/2011/G6P[11] was shown to possess the typical bovine G6 and P[11] genotypes. The complete genome of this unusual lapine strain was sequenced and characterized. Phylogenetic analyses of all 11 gene segments revealed the following genotype constellation: G6-P[11]-I2-R2-C2-M2-A13-N2-T6-E2-H3. The VP1, VP2, VP3, VP6, NSP2 and NSP4 genes all belonged to DS-1-like genotype 2, but clustered more closely to bovine RVA strains than to lapine RVA strains. The NSP1 genotype A13 is typically associated with bovine RVAs, while the NSP3 genotype T6 and the NSP5 genotype H3 have been found in a wide variety of species. However, the isolated strain clustered within bovine(-like) T6 and H3 subclusters. Overall, the data indicate that the RVA strain is most closely related to bovine-like RVA strains and most likely represents a direct interspecies transmission from a cow to a rabbit. Altogether, these findings indicate that a RVA strain with an entirely bovine genome constellation was able to infect and spread in a laboratory rabbit colony.

  4. Expression of immune genes on chromosome 6p21.3-22.1 in schizophrenia.

    PubMed

    Sinkus, Melissa L; Adams, Catherine E; Logel, Judith; Freedman, Robert; Leonard, Sherry

    2013-08-01

    Schizophrenia is a common mental illness with a large genetic component. Three genome-wide association studies have implicated the major histocompatibility complex gene region on chromosome 6p21.3-22.1 in schizophrenia. In addition, nicotine, which is commonly abused in schizophrenia, affects the expression of central nervous system immune genes. Messenger RNA levels for genes in the 6p21.3-22.1 region were measured in human postmortem hippocampus of 89 subjects. The effects of schizophrenia diagnosis, smoking and systemic inflammatory illness were compared. Cell-specific expression patterns for the class I major histocompatibility complex gene HLA-A were explored utilizing in situ hybridization. Expression of five genes was altered in schizophrenic subjects. Messenger RNA levels for the class I major histocompatibility complex antigen HLA-B were increased in schizophrenic nonsmokers, while levels for smokers were indistinguishable from those of controls. β2 microglobulin, HLA-A and Notch4 were all expressed in a pattern where inflammatory illness was associated with increased expression in controls but not in subjects with schizophrenia. Schizophrenia was also associated with increased expression of Butyrophilin 2A2. HLA-A was expressed in glutamatergic and GABAergic neurons in the dentate gyrus, hilus, and the stratum pyramidale of the CA1-CA4 regions of the hippocampus, but not in astrocytes. In conclusion, the expression of genes from the major histocompatibility complex region of chromosome 6 with likely roles in synaptic development is altered in schizophrenia. There were also significant interactions between schizophrenia diagnosis and both inflammatory illness and smoking.

  5. The cytochrome P450 CYP6P4 is responsible for the high pyrethroid resistance in knockdown resistance-free Anopheles arabiensis

    PubMed Central

    Ibrahim, Sulaiman S.; Riveron, Jacob M.; Stott, Robert; Irving, Helen; Wondji, Charles S.

    2016-01-01

    Pyrethroid insecticides are the front line vector control tools used in bed nets to reduce malaria transmission and its burden. However, resistance in major vectors such as Anopheles arabiensis is posing a serious challenge to the success of malaria control. Herein, we elucidated the molecular and biochemical basis of pyrethroid resistance in a knockdown resistance-free Anopheles arabiensis population from Chad, Central Africa. Using heterologous expression of P450s in Escherichia coli coupled with metabolism assays we established that the over-expressed P450 CYP6P4, located in the major pyrethroid resistance (rp1) quantitative trait locus (QTL), is responsible for resistance to Type I and Type II pyrethroid insecticides, with the exception of deltamethrin, in correlation with field resistance profile. However, CYP6P4 exhibited no metabolic activity towards non-pyrethroid insecticides, including DDT, bendiocarb, propoxur and malathion. Combining fluorescent probes inhibition assays with molecular docking simulation, we established that CYP6P4 can bind deltamethrin but cannot metabolise it. This is possibly due to steric hindrance because of the large vdW radius of bromine atoms of the dihalovinyl group of deltamethrin which docks into the heme catalytic centre. The establishment of CYP6P4 as a partial pyrethroid resistance gene explained the observed field resistance to permethrin, and its inability to metabolise deltamethrin probably explained the high mortality from deltamethrin exposure in the field populations of this Sudano-Sahelian An. arabiensis. These findings describe the heterogeneity in resistance towards insecticides, even from the same class, highlighting the need to thoroughly understand the molecular basis of resistance before implementing resistance management/control tools. PMID:26548743

  6. Divergent roles of CXCR3 isoforms in promoting cancer stem-like cell survival and metastasis.

    PubMed

    Li, Yanchun; Reader, Jocelyn C; Ma, Xinrong; Kundu, Namita; Kochel, Tyler; Fulton, Amy M

    2015-01-01

    There is growing evidence that several chemokine receptors including CXCR3 contribute to metastasis of breast and other cancers, however, in order to target CXCR3 effectively, it is critical to understand the relative contribution of each CXCR3 isoform. Furthermore, the possible contribution of either major CXCR3 isoform (CXCR3-A, CXCR3-B) to cancer stem cell behavior has not been reported. We employed primary invasive ductal carcinomas, a panel of breast cell lines, and a xenograft model of metastatic breast cancer to examine the role of CXCR3 isoforms in the behavior of breast cancer stem-like cells and the contribution of each isoform to metastasis. In primary human breast cancer specimens as well as established breast cancer cell lines, CXCR3-A is more highly expressed than CXCR3-B. Conversely, immortalized normal MCF10A cells express more CXCR3-B relative to CXCR3-A. Overexpression of CXCR3-B in MDA-MB-231 basal-like cells inhibits CXCR3 ligand-stimulated proliferation, which is accompanied by reduced ligand-mediated activation of ERK1/2 and p38 kinases. Likewise, metastatic capacity is reduced in vivo by higher levels of CXCR3-B, and migratory and invasive properties are inhibited in vitro; conversely, silencing of CXCR3-B enhances lung colonization. In contrast to the anti-metastatic and anti-proliferative roles of CXCR3-B in the non-stem cell population, this isoform supports a cancer stem-like cell phenotype. CXCR3-B is markedly elevated in mammosphere-forming parental cells and overexpressing CXCR3-B further enhances mammosphere-forming potential as well as growth in soft agar; stem-like behavior is inhibited in MDA-MB-231shCXCR3-B cells. Targeting of both CXCR3 isoforms may be important to block the stem cell-promoting actions of CXCR3-B, while inhibiting the pro-proliferative and metastasis-promoting functions of CXCR3-A.

  7. Expression of pro- and anti-angiogenic isoforms of VEGF is differentially regulated by splicing and growth factors

    PubMed Central

    Nowak, Dawid G.; Woolard, Jeanette; Amin, Elianna Mohamed; Konopatskaya, Olga; Saleem, Moin A.; Churchill, Amanda J.; Ladomery, Michael R.; Harper, Steven J.; Bates, David O.

    2008-01-01

    Summary Vascular endothelial growth factor A (VEGFA; hereafter referred to as VEGF) is a key regulator of physiological and pathological angiogenesis. Two families of VEGF isoforms are generated by alternate splice-site selection in the terminal exon. Proximal splice-site selection (PSS) in exon 8 results in pro-angiogenic VEGFxxx isoforms (xxx is the number of amino acids), whereas distal splice-site selection (DSS) results in anti-angiogenic VEGFxxxb isoforms. To investigate control of PSS and DSS, we investigated the regulation of isoform expression by extracellular growth factor administration and intracellular splicing factors. In primary epithelial cells VEGFxxxb formed the majority of VEGF isoforms (74%). IGF1, and TNFα treatment favoured PSS (increasing VEGFxxx) whereas TGFβ1 favoured DSS, increasing VEGFxxxb levels. TGFβ1 induced DSS selection was prevented by inhibition of p38 MAPK and the Clk/sty (CDC-like kinase, CLK1) splicing factor kinase family, but not ERK1/2. Clk phosphorylates SR protein splicing factors ASF/SF2, SRp40 and SRp55. To determine whether SR splicing factors alter VEGF splicing, they were overexpressed in epithelial cells, and VEGF isoform production assessed. ASF/SF2, and SRp40 both favoured PSS, whereas SRp55 upregulated VEGFxxxb (DSS) isoforms relative to VEGFxxx. SRp55 knockdown reduced expression of VEGF165b. Moreover, SRp55 bound to a 35 nucleotide region of the 3′UTR immediately downstream of the stop codon in exon 8b. These results identify regulation of splicing by growth and splice factors as a key event in determining the relative pro- versus anti-angiogenic expression of VEGF isoforms, and suggest that p38 MAPK-Clk/sty kinases are responsible for the TGFβ1-induced DSS selection, and identify SRp55 as a key regulatory splice factor. PMID:18843117

  8. Analysis of protein isoforms: can we do it better?

    PubMed

    Stastna, Miroslava; Van Eyk, Jennifer E

    2012-10-01

    Protein isoforms/splice variants can play important roles in various biological processes and can potentially be used as biomarkers or therapeutic targets/mediators. Thus, there is a need for efficient and, importantly, accurate methods to distinguish and quantify specific protein isoforms. Since protein isoforms can share a high percentage of amino acid sequence homology and dramatically differ in their cellular concentration, the task for accuracy and efficiency in methodology and instrumentation is challenging. The analysis of intact proteins has been perceived to provide a more accurate and complete result for isoform identification/quantification in comparison to analysis of the corresponding peptides that arise from protein enzymatic digestion. Recently, novel approaches have been explored and developed that can possess the accuracy and reliability important for protein isoform differentiation and isoform-specific peptide targeting. In this review, we discuss the recent development in methodology and instrumentation for enhanced detection of protein isoforms as well as the examples of their biological importance.

  9. Structural Basis of Dscam Isoform Specificity

    SciTech Connect

    Meijers,R.; Puettmann-Holgado, R.; Skiniotis, G.; Liu, J.; Walz, T.; Wang, J.; Schmucker, D.

    2007-01-01

    The Dscam gene gives rise to thousands of diverse cell surface receptors1 thought to provide homophilic and heterophilic recognition specificity for neuronal wiring and immune responses. Mutually exclusive splicing allows for the generation of sequence variability in three immunoglobulin ecto-domains, D2, D3 and D7. We report X-ray structures of the amino-terminal four immunoglobulin domains (D1-D4) of two distinct Dscam isoforms. The structures reveal a horseshoe configuration, with variable residues of D2 and D3 constituting two independent surface epitopes on either side of the receptor. Both isoforms engage in homo-dimerization coupling variable domain D2 with D2, and D3 with D3. These interactions involve symmetric, antiparallel pairing of identical peptide segments from epitope I that are unique to each isoform. Structure-guided mutagenesis and swapping of peptide segments confirm that epitope I, but not epitope II, confers homophilic binding specificity of full-length Dscam receptors. Phylogenetic analysis shows strong selection of matching peptide sequences only for epitope I. We propose that peptide complementarity of variable residues in epitope I of Dscam is essential for homophilic binding specificity.

  10. FSH isoform pattern in classic galactosemia.

    PubMed

    Gubbels, Cynthia S; Thomas, Chris M G; Wodzig, Will K W H; Olthaar, André J; Jaeken, Jaak; Sweep, Fred C G J; Rubio-Gozalbo, M Estela

    2011-04-01

    Female classic galactosemia patients suffer from primary ovarian insufficiency (POI). The cause for this long-term complication is not fully understood. One of the proposed mechanisms is that hypoglycosylation of complex molecules, a known secondary phenomenon of galactosemia, leads to FSH dysfunction. An earlier study showed less acidic isoforms of FSH in serum samples of two classic galactosemia patients compared to controls, indicating hypoglycosylation. In this study, FSH isoform patterns of five classic galactosemia patients with POI were compared to the pattern obtained in two patients with a primary glycosylation disorder (phosphomannomutase-2-deficient congenital disorders of glycosylation, PMM2-CDG) and POI, and in five postmenopausal women as controls. We used FPLC chromatofocussing with measurement of FSH concentration per fraction, and discovered that there were no significant differences between galactosemia patients, PMM2-CDG patients and postmenopausal controls. Our results do not support that FSH dysfunction due to a less acidic isoform pattern because of hypoglycosylation is a key mechanism of POI in this disease.

  11. Differences in sialic acid residues among bone alkaline phosphatase isoforms: a physical, biochemical, and immunological characterization.

    PubMed

    Magnusson, P; Farley, J R

    2002-12-01

    High-performance liquid chromatography (HPLC) separates three human bone alkaline phosphatase (BALP) isoforms in serum; two major BALP isoforms, B1 and B2, and a minor fraction, B/I, which is composed on average of 70% bone and 30% intestinal ALP. The current studies were intended to identify an in vitro source of the BALP isoforms for physical, biochemical, and immunological characterizations. The three BALP isoforms were identified in extracts of human osteosarcoma (SaOS-2) cells, by HPLC, after separation by anion-exchange chromatography. All three BALP isoforms were similar with respect to freeze-thaw stability, solubility, heat inactivation, and inhibition by L-phenylalanine, L-homoarginine, and levamisole. The isoforms were also kinetically similar (i.e., maximal velocity and KM at pH 8.8 and pH 10.0). The isoforms differed, however, with respect to sensitivity to precipitation with wheat germ agglutinin (WGA), P < 0.001, but not Concanavalin A. At 3.0 mg/ml, WGA precipitated approximately 25% of B/I but more than 80% of B1 and B2. Molecular weights were estimated by native gradient gel electrophoresis: B/I, 126 kDa; B1, 136 kDa; and B2, 141 kDa. Desialylation with neuraminidase reduced the apparent sizes of B1 and B2 to 127 kDa (i.e., approximately to that of B/I). The total carbohydrate content was calculated to be 18 kDa, 28 kDa, and 33 kDa (i.e., 14%, 21%, and 23%) for the BALP isofonns, B/I, B1, and B2, respectively. The number of sialic acid residues was estimated to be 29 and 45, for each B1 and B2 homodimer, respectively. Apparent discrepancies between these estimates of molecular weight and estimates based on gel filtration chromatography were attributed to nonspecific interactions between carbohydrate residues and the gel filtration beads. All three BALP isoforms showed similar dose-dependent linearity in the commercial Alkphase-B and Tandem-MP Ostase immunoassays, r = 0.944 and r = 0.985, respectively (P < 0.001). In summary, our data indicate that

  12. Integrated exome and transcriptome sequencing reveals ZAK isoform usage in gastric cancer

    PubMed Central

    Liu, Jinfeng; McCleland, Mark; Stawiski, Eric W.; Gnad, Florian; Mayba, Oleg; Haverty, Peter M.; Durinck, Steffen; Chen, Ying-Jiun; Klijn, Christiaan; Jhunjhunwala, Suchit; Lawrence, Michael; Liu, Hanbin; Wan, Yinan; Chopra, Vivek; Yaylaoglu, Murat B.; Yuan, Wenlin; Ha, Connie; Gilbert, Houston N.; Reeder, Jens; Pau, Gregoire; Stinson, Jeremy; Stern, Howard M.; Manning, Gerard; Wu, Thomas D.; Neve, Richard M.; de Sauvage, Frederic J.; Modrusan, Zora; Seshagiri, Somasekar; Firestein, Ron; Zhang, Zemin

    2014-01-01

    Gastric cancer is the second leading cause of worldwide cancer mortality, yet the underlying genomic alterations remain poorly understood. Here we perform exome and transcriptome sequencing and SNP array assays to characterize 51 primary gastric tumours and 32 cell lines. Meta-analysis of exome data and previously published data sets reveals 24 significantly mutated genes in microsatellite stable (MSS) tumours and 16 in microsatellite instable (MSI) tumours. Over half the patients in our collection could potentially benefit from targeted therapies. We identify 55 splice site mutations accompanied by aberrant splicing products, in addition to mutation-independent differential isoform usage in tumours. ZAK kinase isoform TV1 is preferentially upregulated in gastric tumours and cell lines relative to normal samples. This pattern is also observed in colorectal, bladder and breast cancers. Overexpression of this particular isoform activates multiple cancer-related transcription factor reporters, while depletion of ZAK in gastric cell lines inhibits proliferation. These results reveal the spectrum of genomic and transcriptomic alterations in gastric cancer, and identify isoform-specific oncogenic properties of ZAK. PMID:24807215

  13. Design of isoform-selective phospholipase D inhibitors that modulate cancer cell invasiveness

    PubMed Central

    Scott, Sarah A; Selvy, Paige E; Buck, Jason R; Cho, Hyekyung P; Criswell, Tracy L; Thomas, Ashley L; Armstrong, Michelle D; Arteaga, Carlos L; Lindsley, Craig W; Brown, H Alex

    2013-01-01

    Phospholipase D (PLD) is an essential enzyme responsible for the production of the lipid second messenger phosphatidic acid. Phosphatidic acid participates in both G protein-coupled receptor and receptor tyrosine kinase signal transduction networks. The lack of potent and isoform-selective inhibitors has limited progress in defining the cellular roles of PLD. We used a diversity-oriented synthetic approach and developed a library of PLD inhibitors with considerable pharmacological characterization. Here we report the rigorous evaluation of that library, which contains highly potent inhibitors, including the first isoform-selective PLD inhibitors. Specific members of this series inhibit isoforms with > 100-fold selectivity both in vitro and in cells. A subset of inhibitors was shown to block invasiveness in metastatic breast cancer models. These findings demonstrate the power of diversity-oriented synthesis combined with biochemical assays and mass spectrometric lipid profiling of cellular responses to develop the first isoform-selective PLD inhibitors—a new class of antimetastatic agents. PMID:19136975

  14. Regulation of the viability of Nf1 deficient cells by PKC isoforms.

    PubMed

    Zhou, Xiaodong; Shen, Ling; Parris, Toshima; Huang, Junchi; Yi, Bo; Helou, Khalil; Chen, Changyan

    2014-11-15

    Suppression of protein kinase C (PKC) is known to be synthetically lethal with ras mutations in various types of cancer cells. The studies also showed that blockade of PKC affected the viability of Nf1 deficient cells. Since PKC family consists of more than 10 isoforms, our study aimed at identifying which isoform(s) played the crucial role in sensitizing Nf1 deficient cells to apoptosis. Using genetic and chemical PKC inhibitors, we demonstrated that the concurrent inhibition of PKC α and β induced Nf1 deficient ST or 96.2 cells, but not SNF02.2 cells with a normal Nf1 or ST cells ectopically expressing Nf1 effective domain gene, to apoptosis. In this process, PKC δ in Nf1 deficient cells, but not in ST/Nf1 cells, was upregulated and translocated to the nucleus. Furthermore, caspase 3 was cleaved and cytochrome c was released to the cytosol. Thus, it appeared that PKC δ and α/β are the crucial components for sustaining the aberrant Ras signaling and further viability of Nf1 deficient cells. The abrogation of these two isoforms activated their opponent PKC δ for switching on the caspase 3-governed apoptotic machinery.

  15. NOX isoforms in the development of abdominal aortic aneurysm.

    PubMed

    Siu, Kin Lung; Li, Qiang; Zhang, Yixuan; Guo, Jun; Youn, Ji Youn; Du, Jie; Cai, Hua

    2017-04-01

    Oxidative stress plays an important role in the formation of abdominal aortic aneurysm (AAA), and we have recently established a causal role of uncoupled eNOS in this severe human disease. We have also shown that activation of NADPH oxidase (NOX) lies upstream of uncoupled eNOS. Therefore, identification of the specific NOX isoforms that are required for eNOS uncoupling and AAA formation would ultimately lead to novel therapies for AAA. In the present study, we used the Ang II infused hph-1 mice to examine the roles of NOX isoforms in the development of AAA. We generated double mutants of hph-1-NOX1, hph-1-NOX2, hph-1-p47phox, and hph-1-NOX4. After two weeks of Ang II infusion, the incidence rate of AAA substantially dropped from 76.5% in Ang II infused hph-1 mice (n=34) to 11.1%, 15.0%, 9.5% and 0% in hph-1-NOX1 (n=27), hph-1-NOX2 (n=40), hph-1-p47phox (n=21), and hph-1-NOX4 (n=33) double mutant mice, respectively. The size of abdominal aortas of the four double mutant mice, determined by ultrasound analyses, was significantly smaller than the hph-1 mice. Aortic nitric oxide and H4B bioavailabilities were markedly improved in the double mutants, while superoxide production and eNOS uncoupling activity were substantially diminished. These effects seemed attributed to an endothelial specific restoration of dihydrofolate reductase expression and activity, deficiency of which has been shown to induce eNOS uncoupling and AAA formation in both Ang II-infused hph-1 and apoE null animals. In addition, over-expression of human NOX4 N129S or T555S mutant newly identified in aneurysm patients increased hydrogen peroxide production, further implicating a relationship between NOX and human aneurysm. Taken together, these data indicate that NOX isoforms 1, 2 or 4 lies upstream of dihydrofolate reductase deficiency and eNOS uncoupling to induce AAA formation. These findings may promote development of novel therapeutics for the treatment of the disease by inhibiting NOX signaling.

  16. Role of nuclear progesterone receptor isoforms in uterine pathophysiology

    PubMed Central

    Patel, Bansari; Elguero, Sonia; Thakore, Suruchi; Dahoud, Wissam; Bedaiwy, Mohamed; Mesiano, Sam

    2015-01-01

    BACKGROUND Progesterone is a key hormonal regulator of the female reproductive system. It plays a major role to prepare the uterus for implantation and in the establishment and maintenance of pregnancy. Actions of progesterone on the uterine tissues (endometrium, myometrium and cervix) are mediated by the combined effects of two progesterone receptor (PR) isoforms, designated PR-A and PR-B. Both receptors function primarily as ligand-activated transcription factors. Progesterone action on the uterine tissues is qualitatively and quantitatively determined by the relative levels and transcriptional activities of PR-A and PR-B. The transcriptional activity of the PR isoforms is affected by specific transcriptional coregulators and by PR post-translational modifications that affect gene promoter targeting. In this context, appropriate temporal and cell-specific expression and function of PR-A and PR-B are critical for normal uterine function. METHODS Relevant studies describing the role of PRs in uterine physiology and pathology (endometriosis, uterine leiomyoma, endometrial cancer, cervical cancer and recurrent pregnancy loss) were comprehensively searched using PubMed, Cochrane Library, Web of Science, and Google Scholar and critically reviewed. RESULTS Progesterone, acting through PR-A and PR-B, regulates the development and function of the endometrium and induces changes in cells essential for implantation and the establishment and maintenance of pregnancy. During pregnancy, progesterone via the PRs promotes myometrial relaxation and cervical closure. Withdrawal of PR-mediated progesterone signaling triggers menstruation and parturition. PR-mediated progesterone signaling is anti-mitogenic in endometrial epithelial cells, and as such, mitigates the tropic effects of estrogen on eutopic normal endometrium, and on ectopic implants in endometriosis. Similarly, ligand-activated PRs function as tumor suppressors in endometrial cancer cells through inhibition of key

  17. Efficient Induction of Wheat-Agropyron cristatum 6P Translocation Lines and GISH Detection

    PubMed Central

    Song, Liqiang; Jiang, Lili; Han, Haiming; Gao, Ainong; Yang, Xinming; Li, Lihui; Liu, Weihua

    2013-01-01

    The narrow genetic background restricts wheat yield and quality improvement. The wild relatives of wheat are the huge gene pools for wheat improvement and can broaden its genetic basis. Production of wheat-alien translocation lines can transfer alien genes to wheat. So it is important to develop an efficient method to induce wheat-alien chromosome translocation. Agropyroncristatum (P genome) carries many potential genes beneficial to disease resistance, stress tolerance and high yield. Chromosome 6P possesses the desirable genes exhibiting good agronomic traits, such as high grain number per spike, powdery mildew resistance and stress tolerance. In this study, the wheat-A. cristatum disomic addition was used as bridge material to produce wheat-A. cristatum translocation lines induced by 60Co-γirradiation. The results of genomic in situ hybridization showed that 216 plants contained alien chromosome translocation among 571 self-pollinated progenies. The frequency of translocation was 37.83%, much higher than previous reports. Moreover, various alien translocation types were identified. The analysis of M2 showed that 62.5% of intergeneric translocation lines grew normally without losing the translocated chromosomes. The paper reported a high efficient technical method for inducing alien translocation between wheat and Agropyroncristatum. Additionally, these translocation lines will be valuable for not only basic research on genetic balance, interaction and expression of different chromosome segments of wheat and alien species, but also wheat breeding programs to utilize superior agronomic traits and good compensation effect from alien chromosomes. PMID:23874966

  18. Efficient induction of Wheat-agropyron cristatum 6P translocation lines and GISH detection.

    PubMed

    Song, Liqiang; Jiang, Lili; Han, Haiming; Gao, Ainong; Yang, Xinming; Li, Lihui; Liu, Weihua

    2013-01-01

    The narrow genetic background restricts wheat yield and quality improvement. The wild relatives of wheat are the huge gene pools for wheat improvement and can broaden its genetic basis. Production of wheat-alien translocation lines can transfer alien genes to wheat. So it is important to develop an efficient method to induce wheat-alien chromosome translocation. Agropyroncristatum (P genome) carries many potential genes beneficial to disease resistance, stress tolerance and high yield. Chromosome 6P possesses the desirable genes exhibiting good agronomic traits, such as high grain number per spike, powdery mildew resistance and stress tolerance. In this study, the wheat-A. cristatum disomic addition was used as bridge material to produce wheat-A. cristatum translocation lines induced by (60)Co-γirradiation. The results of genomic in situ hybridization showed that 216 plants contained alien chromosome translocation among 571 self-pollinated progenies. The frequency of translocation was 37.83%, much higher than previous reports. Moreover, various alien translocation types were identified. The analysis of M2 showed that 62.5% of intergeneric translocation lines grew normally without losing the translocated chromosomes. The paper reported a high efficient technical method for inducing alien translocation between wheat and Agropyroncristatum. Additionally, these translocation lines will be valuable for not only basic research on genetic balance, interaction and expression of different chromosome segments of wheat and alien species, but also wheat breeding programs to utilize superior agronomic traits and good compensation effect from alien chromosomes.

  19. β-Amyloid-evoked apoptotic cell death is mediated through MKK6-p66shc pathway.

    PubMed

    Bashir, Muneesa; Parray, Arif A; Baba, Rafia A; Bhat, Hina F; Bhat, Sehar S; Mushtaq, Umar; Andrabi, Khurshid I; Khanday, Firdous A

    2014-03-01

    We have previously shown the involvement of p66shc in mediating apoptosis. Here, we demonstrate the novel mechanism of β-Amyloid-induced toxicity in the mammalian cells. β-Amyloid leads to the phosphorylation of p66shc at the serine 36 residue and activates MKK6, by mediating the phosphorylation at serine 207 residue. Treatment of cells with antioxidants blocks β-Amyloid-induced serine phosphorylation of MKK6, reactive oxygen species (ROS) generation, and hence protected cells against β-Amyloid-induced cell death. Our results indicate that serine phosphorylation of p66shc is carried out by active MKK6. MKK6 knock-down resulted in decreased serine 36 phosphorylation of p66shc. Co-immunoprecipitation results demonstrate a direct physical association between p66shc and WT MKK6, but not with its mutants. Increase in β-Amyloid-induced ROS production was observed in the presence of MKK6 and p66shc, when compared to triple mutant of MKK6 (inactive) and S36 mutant of p66shc. ROS scavengers and knock-down against p66shc, and MKK6 significantly decreased the endogenous level of active p66shc, ROS production, and cell death. Finally, we show that the MKK6-p66shc complex mediates β-Amyloid-evoked apoptotic cell death.

  20. Evidence for a gene influencing reading disability on chromosome 6p in two populations

    SciTech Connect

    Smith, S.D.; Brower, A.M.; Kimberling, W.J.

    1994-09-01

    A genetic contribution to specific reading disability has been demonstrated by twin studies, and segregation analysis has supported a dominant gene effect. In an effort to localize genes influencing reading disability, we have ascertained two independent populations of families: kindreds which were selected to have a three generation history of reading diability in an autosomal dominant pattern; and families with dizygotic twins, at least one of which has been diagnosed with reading disability. All available family members were given a battery of tests to measure reading and spelling ability and intelligence, and qualitative and quantitative phenotypes for reading disability were derived. Blood samples were obtained for genotyping on all consenting family members, in concordance with IRB requirements. Linkage analysis was performed by the sib pair method utilizing the S.A.G.E. (1992) package and by a differential regression technique developed by DeFries and Fulker (1985). In both populations and by both linkage techniques, several markers in the HLA region of chromosome 6p showed results suggestive of linkage, with the effect most pronounced in the twin families. Significance levels were enhanced when only the more severely affected subjects were analyzed with the differential regression technique.

  1. Regulation of CDPK isoforms during tuber development.

    PubMed

    Raíces, Marcela; Gargantini, Pablo Rubén; Chinchilla, Delphine; Crespi, Martín; Téllez-Iñón, María Teresa; Ulloa, Rita María

    2003-07-01

    CDPK activities present during tuber development were analysed. A high CDPK activity was detected in the soluble fraction of early stolons and a lower one was detected in soluble and particulate fractions of induced stolons. The early and late CDPK activities displayed diverse specificity for in vitro substrates and different subcellular distribution. Western blot analysis revealed two CDPKs of 55 and 60 kDa that follow a precise spatial and temporal profile of expression. The 55 kDa protein was only detected in early-elongating stolons and the 60 kDa one was induced upon stolon swelling, correlating with early and late CDPK activities. A new member of the potato CDPK family, StCDPK3, was identified from a stolon cDNA library. Gene specific RT-PCR demonstrated that this gene is only expressed in early stolons, while the previously identified StCDPK1 is expressed upon stolon swelling. This expression profile suggests that StCDPK3 could correspond to the 55 kDa isoform while StCDPK1 could encode the 60 kDa isoform present in swelling stolons. StCDPK1 has myristoylation and palmitoylation consensus possibly involved in its dual intracellular localization. Transient expression studies with wild-type and mutated forms of StCDPK1 fused to GFP were used to show that subcellular localization of this isoform is controlled by myristoylation and palmitoylation. Altogether, our data suggest that sequential activation of StCDPK3 and StCDPK1 and the subcellular localisation of StCDPK1 might be critical regulatory steps of calcium signalling during potato tuber development.

  2. Immune recognition of novel isoforms and domains of the mugwort pollen major allergen Art v 1.

    PubMed

    Dedic, Azra; Gadermaier, Gabriele; Vogel, Lothar; Ebner, Christof; Vieths, Stefan; Ferreira, Fátima; Egger, Matthias

    2009-01-01

    Allergen isoforms can differ in their IgE and T cell recognition patterns, and thus might have an impact on the selection of candidates for molecule-based diagnostic and therapeutic approaches. The present study aimed at the identification and characterization of isoforms of Art v 1, the mugwort pollen major allergen. In addition, single Art v 1 domains were physicochemically and immunologically characterized. For this purpose, the Art v 1 cDNA was radiolabeled and used to screen a mugwort pollen cDNA library. Positive clones were sequenced and used for the production of recombinant proteins in Escherichia coli using the pHIS-Parallel2 vector. Protein purification was performed by affinity- and ion exchange chromatography. Antibody binding to the recombinant proteins was determined by immunoblot, ELISA, cross-inhibition experiments, and mediator release assays. We could identify 7 Art v 1 isoforms differing in 1-6 amino acid residues. Interestingly, all amino acid variations were restricted to the proline domain carrying the molecule's post-translational modifications. No significant difference in IgG or IgE reactivity could be observed between Art v 1 isoforms and the defensin domain produced in E. coli. When expressed in E. coli, the proline domain was not recognized by Art v 1-specific antibodies. Our results demonstrated that the relevant IgE epitopes of Art v 1 are located on the defensin domain and suggest the involvement of carbohydrates in the allergenicity of natural Art v 1. Plant-based expression systems could help to reveal possibly different glycosylation patterns and IgE binding properties of Art v 1 isoforms. These findings have direct implications on the development of novel tools for mugwort pollen allergy diagnosis and therapy.

  3. A comparative study of the action of tolperisone on seven different voltage dependent sodium channel isoforms.

    PubMed

    Hofer, Doris; Lohberger, Birgit; Steinecker, Bibiane; Schmidt, Kurt; Quasthoff, Stefan; Schreibmayer, Wolfgang

    2006-05-24

    The specific, acute interaction of tolperisone, an agent used as a muscle relaxant and for the treatment of chronic pain conditions, with the Na(v1.2), Na(v1.3), Na(v1.4), Na(v1.5), Na(v1.6), Na(v1.7), and Na(v1.8) isoforms of voltage dependent sodium channels was investigated and compared to that of lidocaine. Voltage dependent sodium channels were expressed in the Xenopus laevis oocyte expression system and sodium currents were recorded with the two electrode voltage clamp technique. Cumulative dose response relations revealed marked differences in IC(50) values between the two drugs on identical isoforms, as well as between isoforms. A detailed kinetic analysis uncovered that tolperisone as well as lidocaine exhibited their blocking action not only via state dependent association/dissociation with voltage dependent sodium channels, but a considerable fraction of inhibition is tonic, i.e. permanent and basic in nature. Voltage dependent activation was affected to a minor extent only. A shift in steady-state inactivation to more negative potentials could be observed for most drug/isoform combinations. The contribution of this shift to overall block was, however, small at drug concentrations resulting in considerable overall block. Recovery from inactivation was affected notably by both drugs. Lidocaine application led to a pronounced prolongation of the time constant of the fast recovery process for the Na(v1.3), Na(v1.5), and Na(v1.7) isoforms, indicating common structural properties in the local anesthetic receptor site of these three proteins. Interestingly, this characteristic drug action was not observed for tolperisone.

  4. Cytoskeletal remodeling in differentiated vascular smooth muscle is actin isoform dependent and stimulus dependent.

    PubMed

    Kim, Hak Rim; Gallant, Cynthia; Leavis, Paul C; Gunst, Susan J; Morgan, Kathleen G

    2008-09-01

    Dynamic remodeling of the actin cytoskeleton plays an essential role in the migration and proliferation of vascular smooth muscle cells. It has been suggested that actin remodeling may also play an important functional role in nonmigrating, nonproliferating differentiated vascular smooth muscle (dVSM). In the present study, we show that contractile agonists increase the net polymerization of actin in dVSM, as measured by the differential ultracentrifugation of vascular smooth muscle tissue and the costaining of single freshly dissociated cells with fluorescent probes specific for globular and filamentous actin. Furthermore, induced alterations of the actin polymerization state, as well as actin decoy peptides, inhibit contractility in a stimulus-dependent manner. Latrunculin pretreatment or actin decoy peptides significantly inhibit contractility induced by a phorbol ester or an alpha-agonist, but these procedures have no effect on contractions induced by KCl. Aorta dVSM expresses alpha-smooth muscle actin, beta-actin, nonmuscle gamma-actin, and smooth muscle gamma-actin. The incorporation of isoform-specific cell-permeant synthetic actin decoy peptides, as well as isoform-specific probing of cell fractions and two-dimensional gels, demonstrates that actin remodeling during alpha-agonist contractions involves the remodeling of primarily gamma-actin and, to a lesser extent, beta-actin. Taken together, these results show that net isoform- and agonist-dependent increases in actin polymerization regulate vascular contractility.

  5. Expression of Contractile Protein Isoforms in Microgravity

    NASA Technical Reports Server (NTRS)

    Anderson, Page A. W.

    1996-01-01

    The general objective of this experiment is to determine the effect of space flight parameters, including microgravity, on ontogenesis and embryogenesis of Japanese quail. Nine U.S. and two Russian investigators are cooperating in this study. Specific objectives of the participating scientists include assessing the gross and microscopic morphological and histological development of the embryo, as well as the temporal and spacial development of specific cells, tissues, and organs. Temporally regulated production of specific proteins is also being investigated. Our objective is to determine the effects of microgravity on developmentally programmed expression of Troponin T and I isoforms known to regulate cardiac and skeletal muscle contraction.

  6. Subtelomeric 6p25 deletion/duplication: Report of a patient with new clinical findings and genotype-phenotype correlations.

    PubMed

    Linhares, Natália D; Svartman, Marta; Rodrigues, Tatiane C; Rosenberg, Carla; Valadares, Eugênia R

    2015-05-01

    The 6p terminal deletions are rare and present variability of clinical features, which increases the importance of reporting additional cases in order to better characterize genotype-phenotype correlations. We report a 12-year-old girl with a de novo deletion in 6p25.1-pter characterized by high-resolution karyotyping and FISH. Further analysis using oligonucleotide array-CGH revealed a 5.06 Mb 6p25.1-pter deletion associated with a contiguous 1 Mb 6p25.1 duplication. The patient presented normal growth, developmental delay, frontal bossing, severe hypertelorism, corectopia, wide and depressed nasal bridge, mild learning disability, hearing loss and diffuse leukopathy. Additionaly, she presented peculiar phenotypic features reported herein for the first time in 6p25 deletion syndrome: cerebrospinal fluid fistula and bones resembling those seen in 3-M syndrome. The distinctive phenotype of the 6p25 deletion syndrome has been mainly correlated with the FOXC1 and FOXF2 genes deletions, both related mainly to eye development. We also consider the SERPINB6 as a candidate for sensorineural hearing loss and TUBB2A as a candidate for our patient's skeletal features. In addition, as our patient had a duplication including NRN1, a gene related with neurodevelopment, synaptic plasticity and cognitive dysfunction in schizophrenia, we suggest that this gene could be associated with her white matter abnormalities and neurocognitive phenotype.

  7. Tumorigenic properties of alternative osteopontin isoforms in mesothelioma

    SciTech Connect

    Ivanov, Sergey V.; Ivanova, Alla V.; Goparaju, Chandra M.V.; Chen, Yuanbin; Beck, Amanda; Pass, Harvey I.

    2009-05-08

    Osteopontin (SPP1) is an inflammatory cytokine that we previously characterized as a diagnostic marker in patients with asbestos-induced malignant mesothelioma (MM). While SPP1 shows both pro- and anti-tumorigenic biological effects, little is known about the molecular basis of these activities. In this study, we demonstrate that while healthy pleura possesses all three differentially spliced SPP1 isoforms (A-C), in clinical MM specimens isoform A is markedly up-regulated and predominant. To provide a clue to possible functions of the SPP1 isoforms we next performed their functional evaluation via transient expression in MM cell lines. As a result, we report that isoforms A-C demonstrate different activities in cell proliferation, wound closure, and invasion assays. These findings suggest different functions for SPP1 isoforms and underline pro-tumorigenic properties of isoforms A and B.

  8. VEGFA splicing: divergent isoforms regulate spermatogonial stem cell maintenance

    PubMed Central

    Sargent, Kevin M.; Clopton, Debra T.; Lu, Ningxia; Pohlmeier, William E.

    2015-01-01

    Despite being well-known for regulating angiogenesis in both normal and tumorigenic environments, vascular endothelial growth factor A (VEGFA) has been recently implicated in male fertility, namely in the maintenance of spermatogonial stem cells (SSC). The VEGFA gene can be spliced into multiple distinct isoforms that are either angiogenic or antiangiogenic in nature. Although studies have demonstrated the alternative splicing of VEGFA, including the divergent roles of the two isoform family types, many investigations do not differentiate between them. Data concerning VEGFA in the mammalian testis are limited, but the various angiogenic isoforms appear to promote seminiferous cord formation and to form a gradient across which cells may migrate. Treatment with either antiangiogenic isoforms of VEGFA or with inhibitors to angiogenic signaling impair these processes. Serendipitously, expression of KDR, the primary receptor for both types of VEGFA isoforms, was observed on male germ cells. These findings led to further investigation of the way that VEGFA elicits avascular functions within testes. Following treatment of donor perinatal male mice with either antiangiogenic VEGFA165b or angiogenic VEGFA164 isoforms, seminiferous tubules were less colonized following transplantation with cells from VEGFA165b-treated donors. Thus, VEGFA165b and possibly other antiangiogenic isoforms of VEGFA reduce SSC number either by promoting premature differentiation, inducing cell death, or by preventing SSC formation. Thus, angiogenic isoforms of VEGFA are hypothesized to promote SSC self-renewal, and the divergent isoforms are thought to balance one another to maintain SSC homeostasis in vivo. PMID:26553653

  9. Characterization of the Sucrose Phosphate Phosphatase (SPP) Isoforms from Arabidopsis thaliana and Role of the S6PPc Domain in Dimerization.

    PubMed

    Albi, Tomás; Ruiz, M Teresa; de Los Reyes, Pedro; Valverde, Federico; Romero, José M

    2016-01-01

    Sucrose-phosphate phosphatase (SPP) catalyses the final step in the sucrose biosynthesis pathway. Arabidopsis thaliana genome codifies four SPP isoforms. In this study, the four Arabidopsis thaliana genes coding for SPP isoforms have been cloned, expressed in Escherichia coli and the kinetic and regulatory properties of the purified enzymes analysed. SPP2 is the isoform showing the highest activity, with SPP3b and SPP3a showing lower activity levels. No activity was detected for SPP1. We propose that this lack of activity is probably due to the absence of an essential amino acid participating in catalysis and/or in the binding of the substrate, sucrose-6-phosphate (Suc6P). The expression patterns of Arabidopsis SPP genes indicate that SPP2 and SPP3b are the main isoforms expressed in different tissues and organs, although the non-catalytic SPP1 is the main isoform expressed in roots. Thus, SPP1 could have acquired new unknown functions. We also show that the three catalytically active SPPs from Arabidopsis are dimers. By generating a chimeric SPP composed of the monomeric cyanobacterial SPP fused to the higher plant non-catalytic S6PPc domain (from SPP2), we show that the S6PPc domain is responsible for SPP dimerization. This is the first experimental study on the functionality and gene expression pattern of all the SPPs from a single plant species.

  10. Characterization of the Sucrose Phosphate Phosphatase (SPP) Isoforms from Arabidopsis thaliana and Role of the S6PPc Domain in Dimerization

    PubMed Central

    Albi, Tomás; Ruiz, M. Teresa; de los Reyes, Pedro; Valverde, Federico

    2016-01-01

    Sucrose-phosphate phosphatase (SPP) catalyses the final step in the sucrose biosynthesis pathway. Arabidopsis thaliana genome codifies four SPP isoforms. In this study, the four Arabidopsis thaliana genes coding for SPP isoforms have been cloned, expressed in Escherichia coli and the kinetic and regulatory properties of the purified enzymes analysed. SPP2 is the isoform showing the highest activity, with SPP3b and SPP3a showing lower activity levels. No activity was detected for SPP1. We propose that this lack of activity is probably due to the absence of an essential amino acid participating in catalysis and/or in the binding of the substrate, sucrose-6-phosphate (Suc6P). The expression patterns of Arabidopsis SPP genes indicate that SPP2 and SPP3b are the main isoforms expressed in different tissues and organs, although the non-catalytic SPP1 is the main isoform expressed in roots. Thus, SPP1 could have acquired new unknown functions. We also show that the three catalytically active SPPs from Arabidopsis are dimers. By generating a chimeric SPP composed of the monomeric cyanobacterial SPP fused to the higher plant non-catalytic S6PPc domain (from SPP2), we show that the S6PPc domain is responsible for SPP dimerization. This is the first experimental study on the functionality and gene expression pattern of all the SPPs from a single plant species. PMID:27855180

  11. Differences and similarities in binding of pyruvate and L-lactate in the active site of M4 and H4 isoforms of human lactate dehydrogenase.

    PubMed

    Swiderek, Katarzyna; Paneth, Piotr

    2011-01-01

    We present QM/MM calculations that show differences in geometries of active sites of M(4) and H(4) isoforms of human LDH ligated with oxamate, pyruvate or L-lactate. As the consequence of these differences, binding isotope effects of the methyl hydrogen atoms of pyruvate and l-lactate may be used to experimentally distinguish these isoforms. Based on the FEP calculations we argue that L-lactate is a better candidate for the experimental studies. Our calculations of energies of interactions of ligands with the active site residues provide explanation for the observed experimentally sensitivity to inhibition of the M(4) isoenzyme isoform and pinpoint the differences to interactions of the ligand with the histidine residue. We conclude that pyruvate interacts much stronger in the active site of H(4) than M(4) isoform and that the latter interactions are weaker than with water molecules in the aqueous solution.

  12. Characterization of recombinant long-chain rat acyl-CoA synthetase isoforms 3 and 6: identification of a novel variant of isoform 6.

    PubMed

    Van Horn, Cynthia G; Caviglia, Jorge M; Li, Lei O; Wang, Shuli; Granger, Deborah A; Coleman, Rosalind A

    2005-02-08

    The metabolism of long-chain fatty acids in brain and their incorporation into signaling molecules such as diacylglycerol and LPA and into structural components of membranes, including myelin, requires activation by long-chain acyl-CoA synthetase (ACSL). Because ACSL3 and ACSL6 are the predominant ACSL isoforms in brain, we cloned and characterized these isoforms from rat brain and identified a novel ACSL6 clone (ACSL6_v2). ACSL6_v2 and the previously reported ACSL6_v1 represent splice variants that include exon 13 or 14, respectively. Homologue sequences of both of these variants are present in the human and mouse databases. ACSL3, ACSL6_v1, and ACSL6_v2 with Flag-epitopes at the C-termini were expressed in Escherichia coli and purified on Flag-affinity columns. The three recombinant proteins were characterized. Compared to ACSL4, another brain isoform, ACSL3, ACSL6_v1, and ACSL6_v2 showed similarities in kinetic values for CoA, palmitate, and arachidonate, but their apparent Km values for oleate were 4- to 6-fold lower than for ACSL4. In a direct competition assay with palmitate, all the polyunsaturated fatty acids tested were strong competitors only for ACSL4 with IC50 values of 0.5 to 5 microM. DHA was also strongly preferred by ACSL6_v2. The apparent Km value for ATP of ACSL6_v1 was 8-fold higher than that of ACSL6_v2. ACSL3 and the two variants of ACSL6 were more resistant than ACSL4 to heat inactivation. Despite the high amino acid identity between ACSL3 and ACSL4, rosiglitazone inhibited only ACSL4. Triacsin C, an inhibitor of ACSL1 and ACSL4, also inhibited ACSL3, but did not inhibit the ACSL6 variants. These data further document important differences in the closely related ACSL isoforms and show that amino acid changes near the consensus nucleotide binding site alter function in the two splice variants of ACSL6.

  13. Up-down asymmetry of the electrons ejected from barium 6p{sub 1/2}nk autoionizing states

    SciTech Connect

    Nunkaew, J.; Gallagher, T. F.

    2010-09-15

    We have measured the ejected electron signals from Ba 6p{sub 1/2}nk autoionizing Stark states, of n=28 and 29, produced by linearly polarized laser excitation in weak electric fields. These states do not have well-defined parities and as a result do not lead to angular distributions which are up-down symmetric with respect to the laser polarization direction. The weakness of the electric field makes the observation of the up-down asymmetry of the ejected electrons possible. We observe that the electrons from Ba 6p{sub 1/2}nk autoionizing red states are ejected in the upfield direction, while the electron from Ba 6p{sub 1/2}nk autoionizing blue states are ejected in the downfield direction.

  14. Isoforms of Melanopsin Mediate Different Behavioral Responses to Light

    PubMed Central

    Jagannath, Aarti; Hughes, Steven; Abdelgany, Amr; Pothecary, Carina A.; Di Pretoro, Simona; Pires, Susana S.; Vachtsevanos, Athanasios; Pilorz, Violetta; Brown, Laurence A.; Hossbach, Markus; MacLaren, Robert E.; Halford, Stephanie; Gatti, Silvia; Hankins, Mark W.; Wood, Matthew J.A.; Foster, Russell G.; Peirson, Stuart N.

    2015-01-01

    Summary Melanopsin (OPN4) is a retinal photopigment that mediates a wide range of non-image-forming (NIF) responses to light [1, 2] including circadian entrainment [3], sleep induction [4], the pupillary light response (PLR) [5], and negative masking of locomotor behavior (the acute suppression of activity in response to light) [6]. How these diverse NIF responses can all be mediated by a single photopigment has remained a mystery. We reasoned that the alternative splicing of melanopsin could provide the basis for functionally distinct photopigments arising from a single gene. The murine melanopsin gene is indeed alternatively spliced, producing two distinct isoforms, a short (OPN4S) and a long (OPN4L) isoform, which differ only in their C terminus tails [7]. Significantly, both isoforms form fully functional photopigments [7]. Here, we show that different isoforms of OPN4 mediate different behavioral responses to light. By using RNAi-mediated silencing of each isoform in vivo, we demonstrated that the short isoform (OPN4S) mediates light-induced pupillary constriction, the long isoform (OPN4L) regulates negative masking, and both isoforms contribute to phase-shifting circadian rhythms of locomotor behavior and light-mediated sleep induction. These findings demonstrate that splice variants of a single receptor gene can regulate strikingly different behaviors. PMID:26320947

  15. Isoforms of Melanopsin Mediate Different Behavioral Responses to Light.

    PubMed

    Jagannath, Aarti; Hughes, Steven; Abdelgany, Amr; Pothecary, Carina A; Di Pretoro, Simona; Pires, Susana S; Vachtsevanos, Athanasios; Pilorz, Violetta; Brown, Laurence A; Hossbach, Markus; MacLaren, Robert E; Halford, Stephanie; Gatti, Silvia; Hankins, Mark W; Wood, Matthew J A; Foster, Russell G; Peirson, Stuart N

    2015-09-21

    Melanopsin (OPN4) is a retinal photopigment that mediates a wide range of non-image-forming (NIF) responses to light including circadian entrainment, sleep induction, the pupillary light response (PLR), and negative masking of locomotor behavior (the acute suppression of activity in response to light). How these diverse NIF responses can all be mediated by a single photopigment has remained a mystery. We reasoned that the alternative splicing of melanopsin could provide the basis for functionally distinct photopigments arising from a single gene. The murine melanopsin gene is indeed alternatively spliced, producing two distinct isoforms, a short (OPN4S) and a long (OPN4L) isoform, which differ only in their C terminus tails. Significantly, both isoforms form fully functional photopigments. Here, we show that different isoforms of OPN4 mediate different behavioral responses to light. By using RNAi-mediated silencing of each isoform in vivo, we demonstrated that the short isoform (OPN4S) mediates light-induced pupillary constriction, the long isoform (OPN4L) regulates negative masking, and both isoforms contribute to phase-shifting circadian rhythms of locomotor behavior and light-mediated sleep induction. These findings demonstrate that splice variants of a single receptor gene can regulate strikingly different behaviors.

  16. Tunable protein synthesis by transcript isoforms in human cells

    PubMed Central

    Floor, Stephen N; Doudna, Jennifer A

    2016-01-01

    Eukaryotic genes generate multiple RNA transcript isoforms though alternative transcription, splicing, and polyadenylation. However, the relationship between human transcript diversity and protein production is complex as each isoform can be translated differently. We fractionated a polysome profile and reconstructed transcript isoforms from each fraction, which we term Transcript Isoforms in Polysomes sequencing (TrIP-seq). Analysis of these data revealed regulatory features that control ribosome occupancy and translational output of each transcript isoform. We extracted a panel of 5′ and 3′ untranslated regions that control protein production from an unrelated gene in cells over a 100-fold range. Select 5′ untranslated regions exert robust translational control between cell lines, while 3′ untranslated regions can confer cell type-specific expression. These results expose the large dynamic range of transcript-isoform-specific translational control, identify isoform-specific sequences that control protein output in human cells, and demonstrate that transcript isoform diversity must be considered when relating RNA and protein levels. DOI: http://dx.doi.org/10.7554/eLife.10921.001 PMID:26735365

  17. Cytoplasmic isoforms of Kaposi sarcoma herpesvirus LANA recruit and antagonize the innate immune DNA sensor cGAS

    PubMed Central

    Zhang, Guigen; Chan, Baca; Samarina, Naira; Abere, Bizunesh; Weidner-Glunde, Magdalena; Buch, Anna; Pich, Andreas; Brinkmann, Melanie M.; Schulz, Thomas F.

    2016-01-01

    The latency-associated nuclear antigen (LANA) of Kaposi sarcoma herpesvirus (KSHV) is mainly localized and functions in the nucleus of latently infected cells, playing a pivotal role in the replication and maintenance of latent viral episomal DNA. In addition, N-terminally truncated cytoplasmic isoforms of LANA, resulting from internal translation initiation, have been reported, but their function is unknown. Using coimmunoprecipitation and MS, we found the cGMP-AMP synthase (cGAS), an innate immune DNA sensor, to be a cellular interaction partner of cytoplasmic LANA isoforms. By directly binding to cGAS, LANA, and particularly, a cytoplasmic isoform, inhibit the cGAS-STING–dependent phosphorylation of TBK1 and IRF3 and thereby antagonize the cGAS-mediated restriction of KSHV lytic replication. We hypothesize that cytoplasmic forms of LANA, whose expression increases during lytic replication, inhibit cGAS to promote the reactivation of the KSHV from latency. This observation points to a novel function of the cytoplasmic isoforms of LANA during lytic replication and extends the function of LANA from its role during latency to the lytic replication cycle. PMID:26811480

  18. Tyrosine phosphorylation on spleen tyrosine kinase (Syk) is differentially regulated in human and murine platelets by protein kinase C isoforms.

    PubMed

    Buitrago, Lorena; Bhavanasi, Dheeraj; Dangelmaier, Carol; Manne, Bhanu Kanth; Badolia, Rachit; Borgognone, Alessandra; Tsygankov, Alexander Y; McKenzie, Steven E; Kunapuli, Satya P

    2013-10-04

    Protein kinase C (PKC) isoforms differentially regulate platelet functional responses downstream of glycoprotein VI (GPVI) signaling, but the role of PKCs regulating upstream effectors such as Syk is not known. We investigated the role of PKC on Syk tyrosine phosphorylation using the pan-PKC inhibitor GF109203X (GFX). GPVI-mediated phosphorylation on Syk Tyr-323, Tyr-352, and Tyr-525/526 was rapidly dephosphorylated, but GFX treatment inhibited this dephosphorylation on Tyr-525/526 in human platelets but not in wild type murine platelets. GFX treatment did not affect tyrosine phosphorylation on FcRγ chain or Src family kinases. Phosphorylation of Lat Tyr-191 and PLCγ2 Tyr-759 was also increased upon treatment with GFX. We evaluated whether secreted ADP is required for such dephosphorylation. Exogenous addition of ADP to GFX-treated platelets did not affect tyrosine phosphorylation on Syk. FcγRIIA- or CLEC-2-mediated Syk tyrosine phosphorylation was also potentiated with GFX in human platelets. Because potentiation of Syk phosphorylation is not observed in murine platelets, PKC-deficient mice cannot be used to identify the PKC isoform regulating Syk phosphorylation. We therefore used selective inhibitors of PKC isoforms. Only PKCβ inhibition resulted in Syk hyperphosphorylation similar to that in platelets treated with GFX. This result indicates that PKCβ is the isoform responsible for Syk negative regulation in human platelets. In conclusion, we have elucidated a novel pathway of Syk regulation by PKCβ in human platelets.

  19. Graminicide insensitivity correlates with herbicide-binding co-operativity on acetyl-CoA carboxylase isoforms.

    PubMed

    Price, Lindsey J; Herbert, Derek; Moss, Stephen R; Cole, David J; Harwood, John L

    2003-10-15

    The sensitivity of grass species to important classes of graminicide herbicides inhibiting ACCase (acetyl-CoA carboxylase) is associated with a specific inhibition of the multifunctional ACCase located in the plastids of grasses. In contrast, the multisubunit form of ACCase found in the chloroplasts of dicotyledonous plants is insensitive and the minor cytosolic multifunctional isoforms of the enzyme in both types of plants are also less sensitive to inhibition. We have isolated, separated and characterized the multifunctional ACCase isoforms found in exceptional examples of grasses that are either inherently insensitive to these graminicides, or from biotypes showing acquired resistance to their use. Major and minor multifunctional enzymes were isolated from cell suspension cultures of Festuca rubra and the 'Notts A1'-resistant biotype of Alopecurus myosuroides, and their properties compared with those isolated from cells of wild-type sensitive A. myosuroides or from sensitive maize. Purifications of up to 300-fold were necessary to separate the two isoforms. The molecular masses (200-230 kDa) and K(m) values for all three substrates (ATP, bicarbonate and acetyl-CoA) were similar for the different ACCases, irrespective of their graminicide sensitivity. Moreover, we found no correlation between the ability of isoforms to carboxylate propionyl-CoA and their sensitivity to graminicides. However, insensitive purified forms of ACCase were characterized by herbicide-binding co-operativity, whereas, in contrast, sensitive forms of the enzymes were not. Our studies on isolated individual isoforms of ACCase from grasses support and extend previous indications that herbicide binding co-operativity is the only kinetic property that differentiates naturally or selected insensitive enzymes from the typical sensitive forms usually found in grasses.

  20. Effects of Andrographis paniculata and Orthosiphon stamineus extracts on the glucuronidation of 4-methylumbelliferone in human UGT isoforms.

    PubMed

    Ismail, Sabariah; Hanapi, Nur Aziah; Ab Halim, Mohd Rohaimi; Uchaipichat, Verawan; Mackenzie, Peter I

    2010-05-14

    The effects of Andrographis paniculata and Orthosiphon stamineus extracts on the in vitro glucuronidation of 4-methylumbelliferone (4MU) by recombinant human UGTs, UGT1A1, UGT1A3, UGT1A6, UGT1A7, UGT1A8, UGT1A10, UGT2B7 and UGT2B15 were determined. The potential inhibitory effects of both of the extracts on the activity of each of the UGT isoforms were investigated using 4MU as the substrate. Incubations contained UDP-glucuronic acid (UDPGA) as the cofactor, MgCl(2), cell lysate of respective isoform, and 4MU at the approximate apparent K(m) or S(50) value of each isoform. Final concentrations of Andrographis paniculata and Orthosiphon stamineus extracts used were 0.025, 0.25, 2.5, 25 and 50 microg/mL and 0.01, 0.10, 1.0, 10 and 50 microg/mL respectively. Both extracts variably inhibited the activity of most of the isoforms in a concentration dependent manner. Andrographis paniculata extract was the better inhibitor of all the isoforms studied (IC(50) 1.70 microg/mL for UGT1A3, 2.57 microg/mL for UGT1A8, 2.82 microg/mL for UGT2B7, 5.00 micorg/mL for UGT1A1, 5.66 microg/mL for UGT1A6, 9.88 microg/mL for UGT1A7 and 15.66 microg/mL for UGT1A10). Both extracts showed less than 70% inhibition of UGT2B15, so the IC(50) values were >50 microg/mL. The inhibition of human UGTs by Andrographis paniculata and Orthosiphon stamineus extracts in vitro suggests a potential for drug-herbal extract interactions in the therapeutic setting.

  1. [Radiative transport and collisional transfer of excitation energy in Cs(6P) atoms mixed with N2].

    PubMed

    Meng, Fan-Xin; Qin, Chen; Dai, Kang; Shen, Yi-Fan

    2008-05-01

    Applying the CW laser absorption and fluorescence method, the cross sections for the fine structure mixing and quenching of the Cs(6P) state, induced by collision with N2 molecules, were measured. Cesium atoms were optically excited to the 6P3/2 state. The excited atom density and spatial distribution were mapped by monitoring the absorption of a counterpropagating single mode laser beam, tuned to the 6P1 --> 8S(1/2) transitions, which could be translated parallel to the pump beam. The transmission factors, which describe the average probability that photons emitted within the fluorescence detection region can pass through the optically thick vapor without being absorbed, were calculated for 6P --> 6S(1/2) transitions. The N2 caused line broadening and therefore increased the effective pumping rate and radiative rates. The effective radiative rates were calculated for the 6P(J) --> 6S transitions. The fluorescence intensity I895 of the sensitized 6P(1/2) --> 6S(1/2) emission was measured as a function of N2 density in the range 2 x 10(16) < N < 1.4 x 10(17) cm(-3) at a constant temperature T = 337 K, which produced cesium density N0 = 1.25 x 10(12) cm(-3). The transparency of the cell was obtained by the absorption of light beam passing the cell. The transparency is not a simple function of N2 density. It was found that the quantity N/I895 (I895 being corrected for the cell transparency) exhibited a parabolic dependence on N, confirming that the quenching of the 6P(J) states is due to collision with N2 molecules instead of Cs ground state atoms. The coefficients of the second-order polynomial fitted through the measured data yielded the cross sections sigma3/2 --> 1/2 = (0.42 +/- 0.17) x 10(-16) cm2 and sigmaD = (1.31 +/- 0.52) x 10(-16) cm2 for the 6P(J) fine-structure mixing and quenching, respectively, due to collision with N2 molecules. The quenching rate coefficient is about 3 times larger than the rate coefficient for the fine-structure mixing. Our values for

  2. Precision lifetime measurements of Cs 6p 2P1/2 and 6p 2P3/2 levels by single-photon counting

    NASA Astrophysics Data System (ADS)

    Young, L.; Hill, W. T.; Sibener, S. J.; Price, Stephen D.; Tanner, C. E.; Wieman, C. E.; Leone, Stephen R.

    Time-correlated single-photon counting is used to measure the lifetimes of the 6p 2P1/2 and 6p 2P3/2 levels in atomic Cs with accuracies ≈ 0.2-0.3 %. A high-repetition-rate, femtosecond, self-mode-locked Ti:sapphire laser is used to excite Cs produced in a well-collimated atomic beam. The time interval between the excitation pulse and the arrival of a fluorescence photon is measured repetitively until the desired statistics are obtained. The lifetime results are 34.75(7) and 30.41(10) ns for the 6p 2P1/2 and 6p2P3/2 levels, respectively. These lifetimes fall between those extracted from ab initio many-body perturbation-theory calculations by Blundell, Johnson, and Sapirstein [Phys. Rev. A 43, 3407 (1991)] and V. A. Dzuba et al. [Phys. Lett. A 142, 373 (1989)] and are in all cases within 0.9% of the calculated values. The measurement errors are dominated by systematic effects, and methods to alleviate these and to approach an accuracy of 0.1% are discussed. The technique is a viable alternative to the fast-beam laser approach for measuring lifetimes with extreme accuracy.

  3. Contribution of nitric oxide synthase isoforms to cholinergic vasodilation in murine retinal arterioles.

    PubMed

    Gericke, Adrian; Goloborodko, Evgeny; Sniatecki, Jan J; Steege, Andreas; Wojnowski, Leszek; Pfeiffer, Norbert

    2013-04-01

    Nitric oxide synthases (NOSs) are critically involved in regulation of ocular perfusion. However, the contribution of the individual NOS isoforms to vascular responses is unknown in the retina. Because some previous findings suggested an involvement of inducible nitric oxide synthase (iNOS) in the regulation of retinal vascular tone, a major goal of the present study was to examine the hypothesis that iNOS is involved in mediating cholinergic vasodilation responses of murine retinal arterioles. Another subject of this study was to test the contribution of the other two NOS isoforms, neuronal (nNOS) and endothelial NOS (eNOS), to cholinergic retinal arteriole responses. Expression of individual NOS isoforms was determined in murine retinal arterioles using real-time PCR. All three NOS isoforms were expressed in retinal arterioles. However, eNOS mRNA was found to be most, and iNOS mRNA least abundant. To examine the functional relevance of iNOS for mediating vascular responses, retinal vascular preparations from gene-targeted iNOS-deficient mice (iNOS-/-) and wild-type mice were studied in vitro. Changes in luminal vessel diameter in response to the thromboxane mimetic 9,11-dideoxy-9α,11α-methanoepoxy prostaglandin F2α (U-46619), the endothelium-dependent vasodilator acetylcholine, and the nitric oxide donor nitroprusside were measured by video microscopy. To determine the contribution of individual NOS isoforms to cholinergic vasodilation responses, retinas from iNOS-/- and wild-type mice were incubated with Nω-nitro-l-arginine methyl ester (l-NAME), a non-isoform-selective inhibitor of NOS, 7-nitroindazole, a selective nNOS blocker and aminoguanidine, a selective iNOS inhibitor. U-46619 evoked concentration-dependent vasoconstriction that was similar in retinal arterioles from iNOS-/- and wild-type mice. In retinal arterioles preconstricted with U-46619, acetylcholine and nitroprusside produced dose-dependent dilation that did not differ between iNOS-/- and

  4. Circadian Rhythmicity of Active GSK3 Isoforms Modulates Molecular Clock Gene Rhythms in the Suprachiasmatic Nucleus

    PubMed Central

    Besing, R.C.; Paul, J.R.; Hablitz, L.M.; Rogers, C.O.; Johnson, R.L.; Young, M.E.; Gamble, K.L.

    2015-01-01

    The suprachiasmatic nucleus (SCN) drives and synchronizes daily rhythms at the cellular level via transcriptional-translational feedback loops comprised of clock genes such as Bmal1 and Period (Per). Glycogen synthase kinase 3 (GSK3), a serine/threonine kinase, phosphorylates at least five core clock proteins and shows diurnal variation in phosphorylation state (inactivation) of the GSK3β isoform. Whether phosphorylation of the other primary isoform (GSK3α) varies across the subjective day-night cycle is unknown. The purpose of this study was to determine if the endogenous rhythm of GSK3 (α and β) phosphorylation is critical for rhythmic BMAL1 expression and normal amplitude and periodicity of the molecular clock in the SCN. Significant circadian rhythmicity of phosphorylated GSK3 (α and β) was observed in the SCN from wild-type mice housed in constant darkness for two weeks. Importantly, chronic activation of both GSK3 isoforms impaired rhythmicity of the GSK3 target BMAL1. Furthermore, chronic pharmacological inhibition of GSK3 with 20 μM CHIR-99021 enhanced the amplitude and shortened the period of PER2::luciferase rhythms in organotypic SCN slice cultures. These results support the model that GSK3 activity status is regulated by the circadian clock and that GSK3 feeds back to regulate the molecular clock amplitude in the SCN. PMID:25724980

  5. Expression and characterization of a cytosolic glucose 6 phosphate dehydrogenase isoform from barley (Hordeum vulgare) roots.

    PubMed

    Castiglia, Daniela; Cardi, Manuela; Landi, Simone; Cafasso, Donata; Esposito, Sergio

    2015-08-01

    In plant cells, glucose 6 phosphate dehydrogenase (G6PDH-EC 1.1.1.49) regulates the oxidative pentose phosphate pathway (OPPP), a metabolic route involved in the production of NADPH for various biosynthetic processes and stress response. In this study, we report the overexpression of a cytosolic G6PDH isoform from barley (Hordeum vulgare) roots in bacteria, and the biochemical characterization of the purified recombinant enzyme (HvCy-G6PDH). A full-length cDNA coding for a cytosolic isoform of G6PDH was isolated, and the sequence was cloned into pET3d vector; the protein was overexpressed in Escherichia coli BL21 (DE3) and purified by anion exchange and affinity chromatography. The kinetic properties were calculated: the recombinant HvCy-G6PDH showed KMs and KINADPH comparable to those observed for the enzyme purified from barley roots; moreover, the analysis of NADPH inhibition suggested a competitive mechanism. Therefore, this enzyme could be utilised for the structural and regulatory characterization of this isoform in higher plants.

  6. Epigenomic Promoter Alterations Amplify Gene Isoform and Immunogenic Diversity in Gastric Adenocarcinoma.

    PubMed

    Qamra, Aditi; Xing, Manjie; Padmanabhan, Nisha; Kwok, Jeffrey Jun Ting; Zhang, Shenli; Chang, Xu; Leong, Yan Shan; Lee Lim, Ai Ping; Tang, Qianqao; Ooi, WenFong; Suling Lin, Joyce; Nandi, Tannistha; Yao, Xiaosai; Ong, Xuewen; Lee, Minghui; Tay, Su Ting; Keng, Angie Tan Lay; Gondo Santoso, Erna; Ng, Cedric Chuan Young; Ng, Alvin; Jusakul, Apinya; Smoot, Duane; Ashktorab, Hassan; Rha, Sun Young; Yeoh, Khay Guan; Peng Yong, Wei; Chow, Pierce K H; Chan, Weng Hoong; Ong, Hock Soo; Soo, Khee Chee; Kim, Kyoung-Mee; Wong, Wai Keong; Rozen, Steven G; Teh, Bin Tean; Kappei, Dennis; Lee, Jeeyun; Connolly, John; Tan, Patrick

    2017-03-20

    Promoter elements play important roles in isoform and cell-type specific expression. We surveyed the epigenomic promoter landscape of gastric adenocarcinoma (GC), analyzing 110 chromatin profiles (H3K4me3, H3K4me1, H3K27ac) of primary GCs, GC lines, and non-malignant gastric tissues. We identified ~2000 promoter alterations (somatic promoters), many deregulated in various epithelial malignancies and mapping frequently to alternative promoters within the same gene, generating potential pro-oncogenic isoforms (RASA3). Somatic promoter-associated N-terminal peptides displaying relative depletion in tumors exhibited high-affinity MHC binding predictions and elicited potent T-cell responses in vitro, suggesting a mechanism for reducing tumor antigenicity. In multiple patient cohorts, GCs with high somatic promoter usage also displayed reduced T-cell cytolytic marker expression. Somatic promoters are enriched in PRC2 occupancy, display sensitivity to EZH2 therapeutic inhibition, and are associated with novel cancer-associated transcripts. By generating tumor-specific isoforms and decreasing tumor antigenicity, epigenomic promoter alterations may thus drive intrinsic tumorigenesis and also allow nascent cancers to evade host immunity.

  7. A SPAK isoform switch modulates renal salt transport and blood pressure

    PubMed Central

    McCormick, James A.; Mutig, Kerim; Nelson, Joshua H.; Saritas, Turgay; Hoorn, Ewout J.; Yang, Chao-Ling; Rogers, Shaunessy; Curry, Joshua; Delpire, Eric; Bachmann, Sebastian; Ellison, David H.

    2011-01-01

    The renal thick ascending limb (TAL) and distal convoluted tubule (DCT) play central roles in salt homeostasis and blood pressure regulation. An emerging model suggests that bumetanide and thiazide-sensitive NaCl transporters (NKCC2 and NCC) along these segments are phosphorylated and activated by WNK kinases, via SPAK and OSR1. Here, we show that a kidney-specific SPAK isoform, which lacks the kinase domain, inhibits phosphorylation of NCC and NKCC2 by full-length SPAK, in vitro. Kidney-specific SPAK is highly expressed along the TAL, whereas full-length SPAK is more highly expressed along the DCT. As predicted from the differential expression, SPAK knockout in animals has divergent effects along TAL and DCT, with increased phosphorylated NKCC2 along TAL and decreased phosphorylated NCC along DCT. In mice, extracellular fluid volume depletion shifts SPAK isoform abundance to favor NaCl retention along both segments, indicating that a SPAK isoform switch modulates sodium avidity along the distal nephron. PMID:21907141

  8. Multiple sodium channel isoforms mediate the pathological effects of Pacific ciguatoxin-1.

    PubMed

    Inserra, Marco C; Israel, Mathilde R; Caldwell, Ashlee; Castro, Joel; Deuis, Jennifer R; Harrington, Andrea M; Keramidas, Angelo; Garcia-Caraballo, Sonia; Maddern, Jessica; Erickson, Andelain; Grundy, Luke; Rychkov, Grigori Y; Zimmermann, Katharina; Lewis, Richard J; Brierley, Stuart M; Vetter, Irina

    2017-02-22

    Human intoxication with the seafood poison ciguatoxin, a dinoflagellate polyether that activates voltage-gated sodium channels (NaV), causes ciguatera, a disease characterised by gastrointestinal and neurological disturbances. We assessed the activity of the most potent congener, Pacific ciguatoxin-1 (P-CTX-1), on NaV1.1-1.9 using imaging and electrophysiological approaches. Although P-CTX-1 is essentially a non-selective NaV toxin and shifted the voltage-dependence of activation to more hyperpolarising potentials at all NaV subtypes, an increase in the inactivation time constant was observed only at NaV1.8, while the slope factor of the conductance-voltage curves was significantly increased for NaV1.7 and peak current was significantly increased for NaV1.6. Accordingly, P-CTX-1-induced visceral and cutaneous pain behaviours were significantly decreased after pharmacological inhibition of NaV1.8 and the tetrodotoxin-sensitive isoforms NaV1.7 and NaV1.6, respectively. The contribution of these isoforms to excitability of peripheral C- and A-fibre sensory neurons, confirmed using murine skin and visceral single-fibre recordings, reflects the expression pattern of NaV isoforms in peripheral sensory neurons and their contribution to membrane depolarisation, action potential initiation and propagation.

  9. Multiple sodium channel isoforms mediate the pathological effects of Pacific ciguatoxin-1

    PubMed Central

    Inserra, Marco C.; Israel, Mathilde R.; Caldwell, Ashlee; Castro, Joel; Deuis, Jennifer R.; Harrington, Andrea M.; Keramidas, Angelo; Garcia-Caraballo, Sonia; Maddern, Jessica; Erickson, Andelain; Grundy, Luke; Rychkov, Grigori Y.; Zimmermann, Katharina; Lewis, Richard J.; Brierley, Stuart M.; Vetter, Irina

    2017-01-01

    Human intoxication with the seafood poison ciguatoxin, a dinoflagellate polyether that activates voltage-gated sodium channels (NaV), causes ciguatera, a disease characterised by gastrointestinal and neurological disturbances. We assessed the activity of the most potent congener, Pacific ciguatoxin-1 (P-CTX-1), on NaV1.1–1.9 using imaging and electrophysiological approaches. Although P-CTX-1 is essentially a non-selective NaV toxin and shifted the voltage-dependence of activation to more hyperpolarising potentials at all NaV subtypes, an increase in the inactivation time constant was observed only at NaV1.8, while the slope factor of the conductance-voltage curves was significantly increased for NaV1.7 and peak current was significantly increased for NaV1.6. Accordingly, P-CTX-1-induced visceral and cutaneous pain behaviours were significantly decreased after pharmacological inhibition of NaV1.8 and the tetrodotoxin-sensitive isoforms NaV1.7 and NaV1.6, respectively. The contribution of these isoforms to excitability of peripheral C- and A-fibre sensory neurons, confirmed using murine skin and visceral single-fibre recordings, reflects the expression pattern of NaV isoforms in peripheral sensory neurons and their contribution to membrane depolarisation, action potential initiation and propagation. PMID:28225079

  10. Loss of Functionally Redundant p38 Isoforms in T Cells Enhances Regulatory T Cell Induction*

    PubMed Central

    Hayakawa, Morisada; Hayakawa, Hiroko; Petrova, Tsvetana; Ritprajak, Patcharee; Sutavani, Ruhcha V.; Jiménez-Andrade, Guillermina Yanek; Sano, Yasuyo; Choo, Min-Kyung; Seavitt, John; Venigalla, Ram K. C.; Otsu, Kinya; Georgopoulos, Katia; Arthur, J. Simon C.; Park, Jin Mo

    2017-01-01

    The evolutionarily conserved protein kinase p38 mediates innate resistance to environmental stress and microbial infection. Four p38 isoforms exist in mammals and may have been co-opted for new roles in adaptive immunity. Murine T cells deficient in p38α, the ubiquitously expressed p38 isoform, showed no readily apparent cell-autonomous defects while expressing elevated amounts of another isoform, p38β. Mice with T cells simultaneously lacking p38α and p38β displayed lymphoid atrophy and elevated Foxp3+ regulatory T cell frequencies. Double deficiency of p38α and p38β in naïve CD4+ T cells resulted in an attenuation of MAPK-activated protein kinase (MK)-dependent mTOR signaling after T cell receptor engagement, and enhanced their differentiation into regulatory T cells under appropriate inducing conditions. Pharmacological inhibition of the p38-MK-mTOR signaling module produced similar effects, revealing potential for therapeutic applications. PMID:28011639

  11. Activation of Protein Kinase C Isoforms & Its Impact on Diabetic Complications

    PubMed Central

    Geraldes, Pedro; King, George L

    2010-01-01

    Both cardio- and microvascular complications adversely affect the life quality of patients with diabetes and have been the leading cause of mortality and morbidity in this population. Cardiovascular pathologies of diabetes have an effect on microvenules, arteries, and myocardium. It is believed that hyperglycemia is one of the most important metabolic factors in the development of both micro- and macrovascular complications in diabetic patients. Several prominent hypotheses exist to explain the adverse effect of hyperglycemia. One of them is the chronic activation by hyperglycemia of protein kinase C (PKC), a family of enzymes that are involved in controlling the function of other proteins. PKC has been associated with vascular alterations such as increases in permeability, contractility, extracellular matrix synthesis, cell growth and apoptosis, angiogenesis, leukocyte adhesion, and cytokine activation and inhibition. These perturbations in vascular cell homeostasis caused by different PKC isoforms (PKC-α, -β1/2, and PKC-δ) are linked to the development of pathologies affecting large vessel (atherosclerosis, cardiomyopathy) and small vessel (retinopathy, nephropathy and neuropathy) complications. Clinical trials using a PKC-β isoform inhibitor have been conducted, with some positive results for diabetic nonproliferative retinopathy, nephropathy and endothelial dysfunction. This paper reviews current understanding of how PKC isoforms cause vascular dysfunctions and pathologies in diabetes. PMID:20431074

  12. Array-CGH and clinical characterization in a patient with subtelomeric 6p deletion without ocular dysgenesis.

    PubMed

    Piccione, Maria; Antona, R; Salzano, E; Cavani, S; Malacarne, M; Morreale Bubella, R; Pierluigi, M; Viaggi, C D; Corsello, Giovanni

    2012-01-01

    Subtelomeric terminal 6p deletion has been recognized as a clinically identifiable syndrome including facial dysmorphism, malformation of the anterior eye chamber, hearing loss, heart defects, and developmental delay. Genotype-phenotype correlations of previously published patients have strongly suggested anterior eye segment anomalies as one of the major malformations of the syndrome if the critical 6p25 region contains the FOXC 1 gene. In addition, the presence in this region of one or more genes involved in hearing loss has been hypothesized. We report a patient with a 47,XYY karyotype and submicroscopic terminal 6p deletion. Further characterization of the deletion with array comparative genome hybridization also revealed a cryptic microduplication on chromosome 19. The patient showed dysmorphic features, neuromotor retardation, and profound language impairment, in absence of hearing loss and structural eye anomalies. As far as we know this is the first reported terminal 6p25.1 deletion case without eye dysgenesis precisely characterized by array-CGH. Our result suggests that the genes in this region may not be obvious candidates for hearing loss and demonstrate the need for further elucidation of the function of the genes involved in eye developmental processes.

  13. Genetic locus on chromosome 6p for multicystic renal dysplasia, pelvi-ureteral junction stenosis, and vesicoureteral reflux

    SciTech Connect

    Devriendt, K.; Fryns, J.P.

    1995-11-20

    Robson et al. suggest that renal agenesis, multicystic renal dysplasia (MRD), and uretero-pelvic junction (PUJ) stenosis are pathogenetically related. They proposed a vascular disruption as the cause, with the variable severity of the disorder related to the timing of the abnormal blood supply to the ureteric bud. Alternatively, there exists convincing evidence of a genetic cause transmitted as an autosomal dominant disorder with variable expression, and with a candidate gene localized on chromosome arm 6p. Combinations of these urological malformations occur in the same individual or in different relatives in the same family. In several families with PUJ-stenosis, linkage with the HLA-locus on 6p has been demonstrated. Furthermore, we recently described a patient with a de novo reciprocal translocation involving the same region on 6p in a patient with bilateral multicystic renal dysplasia. Most disease-associated reciprocal translocations appear to have a breakpoint within a candidate gene: therefore, it is reasonable to hypothesize that the breakpoint on 6p in this patient resides within a gene causing MRD. This suggests that mutations in the same gene may lead either to PUJ-stenosis or, when the stenosis is complete, to MRD. A translocation is expected to result in a complete disruption of the gene, and this could explain the severe clinical expression of bilateral MRD. Less severe mutations in the same gene, associated with a partially conserved gene function, could lead to PUJ-stenosis. 11 refs.

  14. The GlcN6P cofactor plays multiple catalytic roles in the glmS ribozyme.

    PubMed

    Bingaman, Jamie L; Zhang, Sixue; Stevens, David R; Yennawar, Neela H; Hammes-Schiffer, Sharon; Bevilacqua, Philip C

    2017-04-01

    RNA enzymes (ribozymes) have remarkably diverse biological roles despite having limited chemical diversity. Protein enzymes enhance their reactivity through recruitment of cofactors; likewise, the naturally occurring glmS ribozyme uses the glucosamine-6-phosphate (GlcN6P) organic cofactor for phosphodiester bond cleavage. Prior structural and biochemical studies have implicated GlcN6P as the general acid. Here we describe new catalytic roles of GlcN6P through experiments and calculations. Large stereospecific normal thio effects and a lack of metal-ion rescue in the holoribozyme indicate that nucleobases and the cofactor play direct chemical roles and align the active site for self-cleavage. Large stereospecific inverse thio effects in the aporibozyme suggest that the GlcN6P cofactor disrupts an inhibitory interaction of the nucleophile. Strong metal-ion rescue in the aporibozyme reveals that this cofactor also provides electrostatic stabilization. Ribozyme organic cofactors thus perform myriad catalytic roles, thereby allowing RNA to compensate for its limited functional diversity.

  15. Application of substrate depletion assay to evaluation of CYP isoforms responsible for stereoselective metabolism of carvedilol.

    PubMed

    Iwaki, Masahiro; Niwa, Toshiro; Bandoh, Saya; Itoh, Megumi; Hirose, Hitomi; Kawase, Atsushi; Komura, Hiroshi

    2016-12-01

    To evaluate the relative contribution of cytochrome P450 (CYP) isoforms responsible for carvedilol (CAR) oxidation, enantioselective metabolism of CAR was investigated in human liver microsomes (HLMs) and recombinant human CYPs by using the substrate depletion assay. CYP2D6 exhibited the highest contribution to the metabolism of R-CAR, followed by CYP3A4, CYP1A2, and CYP2C9, whereas the metabolism of the S-enantiomer was mainly mediated by CYP1A2, followed by CYP2D6 and CYP3A4. In HLMs, metabolism of R- and S-CAR was markedly inhibited by quinidine; R-CAR metabolism (57-61% decrease) was more inhibited than S-CAR metabolism (37-43% decrease), and furafylline and ketoconazole almost equally inhibited metabolism of both enantiomers by 25-32% and 30-50%, respectively. The absence of CYP2D6 in a mixture of five major recombinant CYP isoforms at the approximate ratio as in HLMs resulted in a 42% and 25% decrease in the metabolic activities for R- and S-CAR, respectively. Moreover, the absence of CYP1A2 in the mixture resulted in a 16% and 39% decrease in the metabolic activities for R- and S-CAR, respectively. Our results suggest the stereoselective metabolism of CAR is determined by not only the activity of CYP2D6 but also of CYP1A2 and CYP3A4.

  16. DIFERENTIALLY EXPRESSED ADENYLYL CYCLASE ISOFORMS MEDIATE SECRETORY FUNCTIONS IN CHOLANGIOCYTE SUBPOPULATION

    PubMed Central

    Strazzabosco, Mario; Fiorotto, Romina; Melero, Saida; Glaser, Shannon; Francis, Heather; Spirlì, Carlo; Alpini, Gianfranco

    2009-01-01

    cAMP is generated by adenylyl cyclases (ACs) a group of enzymes with different tissue specificity and regulation. We hypothesized that AC isoforms are heterogeneously expressed along the biliary tree, are associated with specific secretory stimuli and are differentially modulated in cholestasis. Methods: Small (SDC) and large (LDC) cholangiocytes were isolated from controls and from lipopolysaccharide-treated (LPS) or α-naphthylisothiocyanate-treated (ANIT) rats. ACs isoforms expression was assessed by real-time PCR. Secretion and cAMP levels were measured in intrahepatic bile duct units after stimulation with secretin, forskolin, HCO3−/CO2, cholinergic and β-adrenergic agonists, with or without selected inhibitors or after silencing of AC8 or sAC with siRNA. Results: Gene expression of the Ca2+-insensitive isoforms (AC4, AC7) was higher in SDC, while that of the Ca2+-inhibitable (AC5, AC6, AC9), the Ca2+/calmodulin stimulated AC8, and the soluble sAC, was higher in LDC. Ca2+/calmodulin-inhibitors and AC8 gene silencing inhibited choleresis and cAMP production stimulated by secretin and acetylcholine, but not by forskolin. Secretion stimulated by isoproterenol and calcineurin-inibitors was cAMP-dependent and GABA-inhibitable, consistent with activation of AC9. Cholangiocyte secretion stimulated by isohydric changes in [HCO3−]i, was cAMP-dependent and inhibited by sAC-inhibitior and by sAC gene silencing. Treatment with LPS or ANIT increased expression of AC7 and sAC, while decreasing that of the others ACs. Conclusion: These studies demonstrate a previously unrecognized role of AC in biliary pathophysiology. In fact: 1) ACs isoforms are differentially expressed in cholangiocyte subpopulations, 2) AC8, AC9, and sAC mediate cholangiocyte secretion in response to secretin, β-adrenergic agonists, or changes in [HCO3−]i, respectively, 3) ACs gene expression is modulated in experimental cholestasis. PMID:19444869

  17. Redundant ecdysis regulatory functions of three nuclear receptor HR3 isoforms in the direct-developing insect Blattella germanica.

    PubMed

    Cruz, Josefa; Martín, David; Bellés, Xavier

    2007-03-01

    In hemimetabolous insects, the molecular basis of the 20-hydroxyecdysone (20E)-triggered genetic hierarchy is practically unknown. In the cockroach Blattella germanica, we had previously characterized one isoform of the ecdysone receptor, BgEcR-A, and two isoforms of its heterodimeric partner, BgRXR-S and BgRXR-L. One of the early-late genes of the 20E-triggered genetic hierarchy, is HR3. In the present paper, we report the discovery of three isoforms of HR3 in B. germanica, that were named BgHR3-A, BgHR3-B(1) and BgHR3-B(2). Expression studies in prothoracic gland, epidermis and fat body indicate that the expression of the three isoforms coincides with the peak of circulating ecdysteroids at each nymphal instar. Experiments in vitro with fat body tissue have shown that 20E induces the expression of BgHR3 isoforms, and that incubation with 20E and the protein inhibitor cycloheximide does not inhibit the induction, which indicates that the effect of 20E on BgHR3 activation is direct. This has been further confirmed by RNAi in vivo of BgEcR-A, which has shown that this nuclear receptor is required to fully activate the expression of BgHR3. RNAi has been also used to demonstrate the functions of BgHR3 in ecdysis. Nymphs with silenced BgHR3 completed the apolysis but were unable to ecdyse (they had duplicated and superimposed the mouth parts, the hypopharinge, the tracheal system and the cuticle layers). This indicates that BgHR3 is directly involved in ecdysis. Finally, RNAi of specific isoforms has showed that they are functionally redundant, at least regarding the ecdysis process.

  18. Cell elasticity is regulated by the tropomyosin isoform composition of the actin cytoskeleton.

    PubMed

    Jalilian, Iman; Heu, Celine; Cheng, Hong; Freittag, Hannah; Desouza, Melissa; Stehn, Justine R; Bryce, Nicole S; Whan, Renee M; Hardeman, Edna C; Fath, Thomas; Schevzov, Galina; Gunning, Peter W

    2015-01-01

    The actin cytoskeleton is the primary polymer system within cells responsible for regulating cellular stiffness. While various actin binding proteins regulate the organization and dynamics of the actin cytoskeleton, the proteins responsible for regulating the mechanical properties of cells are still not fully understood. In the present study, we have addressed the significance of the actin associated protein, tropomyosin (Tpm), in influencing the mechanical properties of cells. Tpms belong to a multi-gene family that form a co-polymer with actin filaments and differentially regulate actin filament stability, function and organization. Tpm isoform expression is highly regulated and together with the ability to sort to specific intracellular sites, result in the generation of distinct Tpm isoform-containing actin filament populations. Nanomechanical measurements conducted with an Atomic Force Microscope using indentation in Peak Force Tapping in indentation/ramping mode, demonstrated that Tpm impacts on cell stiffness and the observed effect occurred in a Tpm isoform-specific manner. Quantitative analysis of the cellular filamentous actin (F-actin) pool conducted both biochemically and with the use of a linear detection algorithm to evaluate actin structures revealed that an altered F-actin pool does not absolutely predict changes in cell stiffness. Inhibition of non-muscle myosin II revealed that intracellular tension generated by myosin II is required for the observed increase in cell stiffness. Lastly, we show that the observed increase in cell stiffness is partially recapitulated in vivo as detected in epididymal fat pads isolated from a Tpm3.1 transgenic mouse line. Together these data are consistent with a role for Tpm in regulating cell stiffness via the generation of specific populations of Tpm isoform-containing actin filaments.

  19. Cell Elasticity Is Regulated by the Tropomyosin Isoform Composition of the Actin Cytoskeleton

    PubMed Central

    Jalilian, Iman; Heu, Celine; Cheng, Hong; Freittag, Hannah; Desouza, Melissa; Stehn, Justine R.; Bryce, Nicole S.; Whan, Renee M.; Hardeman, Edna C.

    2015-01-01

    The actin cytoskeleton is the primary polymer system within cells responsible for regulating cellular stiffness. While various actin binding proteins regulate the organization and dynamics of the actin cytoskeleton, the proteins responsible for regulating the mechanical properties of cells are still not fully understood. In the present study, we have addressed the significance of the actin associated protein, tropomyosin (Tpm), in influencing the mechanical properties of cells. Tpms belong to a multi-gene family that form a co-polymer with actin filaments and differentially regulate actin filament stability, function and organization. Tpm isoform expression is highly regulated and together with the ability to sort to specific intracellular sites, result in the generation of distinct Tpm isoform-containing actin filament populations. Nanomechanical measurements conducted with an Atomic Force Microscope using indentation in Peak Force Tapping in indentation/ramping mode, demonstrated that Tpm impacts on cell stiffness and the observed effect occurred in a Tpm isoform-specific manner. Quantitative analysis of the cellular filamentous actin (F-actin) pool conducted both biochemically and with the use of a linear detection algorithm to evaluate actin structures revealed that an altered F-actin pool does not absolutely predict changes in cell stiffness. Inhibition of non-muscle myosin II revealed that intracellular tension generated by myosin II is required for the observed increase in cell stiffness. Lastly, we show that the observed increase in cell stiffness is partially recapitulated in vivo as detected in epididymal fat pads isolated from a Tpm3.1 transgenic mouse line. Together these data are consistent with a role for Tpm in regulating cell stiffness via the generation of specific populations of Tpm isoform-containing actin filaments. PMID:25978408

  20. Structural Basis of Protein Kinase C Isoform Function

    PubMed Central

    STEINBERG, SUSAN F.

    2010-01-01

    Protein kinase C (PKC) isoforms comprise a family of lipid-activated enzymes that have been implicated in a wide range of cellular functions. PKCs are modular enzymes comprised of a regulatory domain (that contains the membrane-targeting motifs that respond to lipid cofactors, and in the case of some PKCs calcium) and a relatively conserved catalytic domain that binds ATP and substrates. These enzymes are coexpressed and respond to similar stimulatory agonists in many cell types. However, there is growing evidence that individual PKC isoforms subserve unique (and in some cases opposing) functions in cells, at least in part as a result of isoform-specific subcellular compartmentalization patterns, protein-protein interactions, and posttranslational modifications that influence catalytic function. This review focuses on the structural basis for differences in lipid cofactor responsiveness for individual PKC isoforms, the regulatory phosphorylations that control the normal maturation, activation, signaling function, and downregulation of these enzymes, and the intra-/intermolecular interactions that control PKC isoform activation and subcellular targeting in cells. A detailed understanding of the unique molecular features that underlie isoform-specific posttranslational modification patterns, protein-protein interactions, and subcellular targeting (i.e., that impart functional specificity) should provide the basis for the design of novel PKC isoform-specific activator or inhibitor compounds that can achieve therapeutically useful changes in PKC signaling in cells. PMID:18923184

  1. Nonmuscle myosin II isoforms coassemble in living cells.

    PubMed

    Beach, Jordan R; Shao, Lin; Remmert, Kirsten; Li, Dong; Betzig, Eric; Hammer, John A

    2014-05-19

    Nonmuscle myosin II (NM II) powers myriad developmental and cellular processes, including embryogenesis, cell migration, and cytokinesis [1]. To exert its functions, monomers of NM II assemble into bipolar filaments that produce a contractile force on the actin cytoskeleton. Mammalian cells express up to three isoforms of NM II (NM IIA, IIB, and IIC), each of which possesses distinct biophysical properties and supports unique as well as redundant cellular functions [2-8]. Despite previous efforts [9-13], it remains unclear whether NM II isoforms assemble in living cells to produce mixed (heterotypic) bipolar filaments or whether filaments consist entirely of a single isoform (homotypic). We addressed this question using fluorescently tagged versions of NM IIA, IIB, and IIC, isoform-specific immunostaining of the endogenous proteins, and two-color total internal reflection fluorescence structured-illumination microscopy, or TIRF-SIM, to visualize individual myosin II bipolar filaments inside cells. We show that NM II isoforms coassemble into heterotypic filaments in a variety of settings, including various types of stress fibers, individual filaments throughout the cell, and the contractile ring. We also show that the differential distribution of NM IIA and NM IIB typically seen in confocal micrographs of well-polarized cells is reflected in the composition of individual bipolar filaments. Interestingly, this differential distribution is less pronounced in freshly spread cells, arguing for the existence of a sorting mechanism acting over time. Together, our work argues that individual NM II isoforms are potentially performing both isoform-specific and isoform-redundant functions while coassembled with other NM II isoforms.

  2. Molecular cloning of ID4, a novel dominant negative helix-loop-helix human gene on chromosome 6p21.3-p22

    SciTech Connect

    Pagliuca, A.; Bartoli, P.C.; Saccone, S.

    1995-05-01

    Transcription factors containing a basic helix-loop-helix (bHLH) motif regulate the expression of tissue-specific genes in a number of mammalian and insect systems. DNA-binding activity of the bHLH proteins is dependent upon formation of homo- and/or heterodimers. Dominant negative HLH proteins (Id-related genes) also contain the HLH-dimerization domain but lack the DNA-binding basic domain. Consequently, Id proteins inhibit binding to DNA and transcriptional transactivation by heterodimerization with bHLH proteins. The authors report here the cDNA sequence of a novel human HLH gene (HGMW-approved symbol ID4) that lacks the basic domain. ID4 is differentially expressed in adult organs in four mRNA molecules, which are presumably a result of differential splicing and/or alternative usage of the polyadenylation sites. Transfection experiments indicated that enforced expression of Id-4H protein inhibits the trans-activation of the muscle creatine kinase E-box enhancer by MyoD. Finally, the authors localized the ID4 gene to the chromosome 6p21-p22 region. 18 refs., 4 figs.

  3. IsoSel: Protein Isoform Selector for phylogenetic reconstructions

    PubMed Central

    Philippon, Héloïse; Souvane, Alexia; Brochier-Armanet, Céline

    2017-01-01

    The reliability of molecular phylogenies is strongly dependent on the quality of the assembled datasets. In the case of eukaryotes, the selection of only one protein isoform per genomic locus is mandatory to avoid biases linked to redundancy. Here, we present IsoSel, a tool devoted to the selection of alternative isoforms in the context of phylogenetic reconstruction. It provides a better alternative to the widely used approach consisting in the selection of the longest isoforms and it performs better than Guidance, its only available counterpart. IsoSel is publicly available at http://doua.prabi.fr/software/isosel. PMID:28323858

  4. Differential localization of tropomyosin isoforms in cultured nonmuscle cells

    PubMed Central

    1988-01-01

    We have previously shown that chicken embryo fibroblast (CEF) cells and human bladder carcinoma (EJ) cells contain multiple isoforms of tropomyosin, identified as a, b, 1, 2, and 3 in CEF cells and 1, 2, 3, 4, and 5 in human EJ cells by one-dimensional SDS-PAGE (Lin, J. J.-C., D. M. Helfman, S. H. Hughes, and C.-S. Chou. 1985. J. Cell Biol. 100: 692-703; and Lin, J. J.-C., S. Yamashiro-Matsumura, and F. Matsumura. 1984. Cancer Cells 1:57-65). Both isoform 3 (TM-3) of CEF and isoforms 4,5 (TM-4,-5) of human EJ cells are the minor isoforms found respectively in normal chicken and human cells. They have a lower apparent molecular mass and show a weaker affinity to actin filaments when compared to the higher molecular mass isoforms. Using individual tropomyosin isoforms immobilized on nitrocellulose papers and sequential absorption of polyclonal antiserum on these papers, we have prepared antibodies specific to CEF TM-3 and to CEF TM-1,-2. In addition, two of our antitropomyosin mAbs, CG beta 6 and CG3, have now been demonstrated by Western blots, immunoprecipitation, and two- dimensional gel analysis to have specificities to human EJ TM-3 and TM- 5, respectively. By using these isoform-specific reagents, we are able to compare the intracellular localizations of the lower and higher molecular mass isoforms in both CEF and human EJ cells. We have found that both lower and higher molecular mass isoforms of tropomyosin are localized along stress fibers of cells, as one would expect. However, the lower molecular mass isoforms are also distributed in regions near ruffling membranes. Further evidence for this different localization of different tropomyosin isoforms comes from double-label immunofluorescence microscopy on the same CEF cells with affinity- purified antibody against TM-3, and monoclonal CG beta 6 antibody against TM-a, -b, -1, and -2 of CEF tropomyosin. The presence of the lower molecular mass isoform of tropomyosin in ruffling membranes may indicate a novel

  5. Distribution of caveolin isoforms in the lemur retina.

    PubMed

    Berta, Agnes I; Kiss, Anna L; Lukáts, Akos; Szabó, Arnold; Szél, Agoston

    2007-09-01

    The distribution of caveolin isoforms was previously evaluated in the retinas of different species, but has not yet been described in the primate retina. In this study, the distribution of caveolins was assessed via immunochemistry using isoform-specific antibodies in the retina of the black-and-white ruffed lemur. Here, we report the presence of a variety of caveolin isoforms in many layers of the lemur retina. As normal human retinas were not available for research and the retinas of primates are fairly similar to those of humans, the lemur retina can be utilized as a model for caveolin distribution in normal humans.

  6. Targeted Proteomics Enables Simultaneous Quantification of Folate Receptor Isoforms and Potential Isoform-based Diagnosis in Breast Cancer

    PubMed Central

    Yang, Ting; Xu, Feifei; Fang, Danjun; Chen, Yun

    2015-01-01

    The distinct roles of protein isoforms in cancer are becoming increasingly evident. FRα and FRβ, two major isoforms of the folate receptor family, generally have different cellular distribution and tissue specificity. However, the presence of FRβ in breast tumors, where FRα is normally expressed, complicates this situation. Prior to applying any FR isoform-based diagnosis and therapeutics, it is essential to monitor the expression profile of FR isoforms in a more accurate manner. An LC-MS/MS-based targeted proteomics assay was developed and validated in this study because of the lack of suitable methodology for the simultaneous and specific measurement of highly homologous isoforms occurring at low concentrations. FRα and FRβ monitoring was achieved by measuring their surrogate isoform-specific peptides. Five human breast cell lines, isolated macrophages and 60 matched pairs of breast tissue samples were subjected to the analysis. The results indicated that FRβ was overexpressed in tumor-associated macrophages (TAMs) but not epithelial cells, in addition to an enhanced level of FRα in breast cancer cells and tissue samples. Moreover, the levels of the FR isoforms were evaluated according to the histology, histopathological features and molecular subtypes of breast cancer. Several positive associations with PR/ER and HER2 status and metastasis were revealed. PMID:26573433

  7. Inhibition of pear fruit ripening by mannose.

    PubMed

    Watkins, C B; Frenkel, C

    1987-09-01

    Softening of the flesh and the rise in ethylene evolution and respiration associated with ripening in pear (Pyrus communis L.) fruit was delayed when mannose was vacuum infiltrated into intact fruit. The extent of delay could be modified by altering the concentration or the volume of mannose applied to the fruit. Inhibition of ripening was associated with phosphorylation of mannose to mannose 6-phosphate (M6P), and accumulation of M6P was associated with lowered levels of inorganic phosphate (Pi), glucose 6-phosphate (G6P), and ATP in the fruit tissue. Subsequently, however, as the M6P was metabolized, the levels of Pi, G6P, and ATP increased and ripening processes were concomitantly released from inhibition. Hence, the degree of inhibition by mannose or the release from inhibition was related to the level of M6P in the fruit and its rate of metabolism. The data provide correlative evidence to support a view that one inhibitory effect of mannose is depletion of Pi in the cell as a result of phosphorylation of mannose to M6P. Inhibition of ripening by mannose was not alleviated by co-application of glucose as a competitive substrate for the hexokinase(s), or by Pi, presumably the depleted metabolite. Also, incubation of tissue disks with M6P resulted in inhibition of ethylene production and respiration. The structural analogs of mannose, glucosamine, and 2-deoxyglucose, which have been shown to mimic mannose action in several plant tissues, did not cause inhibition of ripening of pear fruit comparable with that associated with mannose. Both analogs stimulated respiration, and glucosamine caused only a small inhibition of softening and ethylene evolution. Another mannose analog, alpha-methylmannoside, did inhibit fruit ripening though to a lesser extent than mannose. Its influence was also associated with accumulation of M6P and a decrease of Pi levels. We conclude that the mannose effect may, in part, be due to M6P toxicity, as well as by depletion of Pi.

  8. RELATIONSHIP BETWEEN BRAIN AND OVARY AROMATASE ACTIVITY AND ISOFORM-SPECIFIC AROMATASE MRNA EXPRESSION IN THE FATHEAD MINNOW (PIMEPHALES PROMELAS) - JOURNAL ARTICLE

    EPA Science Inventory

    There is growing evidence that some chemicals present in the environment have the capacity to inhibit, or potentially induce, aromatase activity. This study compared aromatase activities and isoform-specific mRNA expression in brain and ovary tissue from non-exposed fathead minn...

  9. Effect of hypoxia on the transcription pattern of subunit isoforms and the kinetics of cytochrome c oxidase in cortical astrocytes and cerebellar neurons.

    PubMed

    Horvat, Susann; Beyer, Cordian; Arnold, Susanne

    2006-11-01

    Brain energy metabolism essentially depends on the availability of oxygen representing the energetic substrate for cytochrome c oxidase (COX). The catalytic activity of mammalian COX is regulated by binding of ATP to the N-terminus of subunit IV. This causes an allosteric inhibition of the enzyme at a high energy level and thus plays an important role in adjusting energy production to cellular energy requirements. We have studied COX activity in cortical astrocytes and cerebellar granule cells after normoxia and hypoxia treatment. Differences in the kinetic behaviour of COX from these two brain cell types can be addressed to a differential, but cell type-specific, expression of the COX subunit IV-2 isoform. Besides COX isoform IV-1, which is ubiquitously transcribed in all mammalian tissues, we also detected low levels of COX isoform IV-2 in cerebellar neurons, but not in cortical astrocytes. Under conditions of oxygen deprivation, transcription of COX IV-2 is induced in astrocytes and further up-regulated in cerebellar granule cells. Elevated transcription levels of the COX IV-2 isoform are accompanied by an abolition of the allosteric inhibition of COX by ATP. We conclude that the presence of the COX isoform IV-2 suppresses the sensitivity of COX to its allosteric regulator ATP and overrules the regulation of COX by the cellular energy level. This suggests a pivotal role of COX as an oxygen sensor for brain function.

  10. Role of trehalose-6P phosphatase (TPS2) in stress tolerance and resistance to macrophage killing in Candida albicans.

    PubMed

    Martínez-Esparza, María; Martínez-Vicente, Encarnación; González-Párraga, Pilar; Ros, José M; García-Peñarrubia, Pilar; Argüelles, Juan-Carlos

    2009-08-01

    Disruption of the TPS2 gene encoding the only trehalose-6P phosphatase activity in Candida albicans caused a pleiotropic defective phenotype, maintaining the cell wall integrity and the ability to form chlamydospores. A homozygous tps2Delta/tps2Delta showed reduced growth at high temperatures and a marked sensitivity to heat shock (42 degrees C) and severe oxidative exposure (50mM H(2)O(2)). Reintroduction of the TPS2 gene reversed these alterations. A more detailed study of the antioxidant response showed that exponential tps2Delta null cells displayed an adaptive response to oxidative stress as well as cross-tolerance between temperature and oxidative stress. Differential measurement of trehalose and trehalose-6P, using reliable new HPLC methodology, revealed a significant accumulation of trehalose-6P in tps2Delta cells, which was enhanced after oxidative exposure. In contrast, the level of trehalose-6P in parental cells was virtually undetectable, and oxidative treatment only induced the synthesis of free trehalose. A transitory increase in the expression of TPS2 and TPS1 genes was promoted in wild-type cells in response to acute (50mM) but not gentle (5mM) oxidative exposure. TPS1 and TPS2 oxidative-induced transcriptions were completely absent from the tps2Delta mutant. Exponential blastoconidia from both parental and tps2Delta/tps2Delta strains were completely phagocytosed by murine and human macrophages, triggering a subsequent proinflammatory response manifested by the release of TNF-alpha. Reflecting the lower resistance to oxidative stress displayed by the tps2Delta mutant, intracellular survival in resting and IFN-gamma and LPS-stimulated macrophages was also diminished. Taken together, our results confirm the mainly protective role played by the trehalose biosynthetic pathway in the cellular response to oxidative stress and subsequently in the resistance to phagocytosis in C. albicans, a defensive mechanism in which TPS2 would be involved.

  11. Genomic Imprinting of the M6P/IGF2 Receptor: A Novel Breast Cancer Susceptibility Mechanism

    DTIC Science & Technology

    2000-07-01

    embryonic growth and development. They also are involved in cancer because their functional haploid state makes them vulnerable to being either inactivated or...Breast Cancer, Genomic Imprinting, M6P/IGF2R, Tumor Suppressor, 7 Imprinting Evolution I_16._PRICECODE 16. PRICE CODE 17. SECURITY CLASSIFICATION 18...tissues not available for our analysis. However, recent experimental evidence from our laboratory, based on a detailed analysis of the evolution of

  12. Whole genome characterization of a G6P[5] rotavirus A strain isolated from a stray cat in Japan.

    PubMed

    Kaneko, Miho; Mochizuki, Masami; Nakagomi, Osamu; Nakagomi, Toyoko

    2016-05-30

    The whole genome of an unusual G6P[5] rotavirus A strain named FRV537, which was isolated from a stray cat in Japan, was characterized to determine its species of origin. The genotype constellation of FRV537 was G6-P[5]-I2-R2-C2-M2-A13-N2- T6-E2-H3. No known feline rotavirus has this genotype constellation; the Japanese equine strain OH-4 is the only known strain that does. While FRV537 shares the same genotype with some feline rotaviruses in all genes except those encoding VP4 and NSP1, none of these genes are closely related to those of known feline rotaviruses. By contrast, G6P[5] is almost exclusively present in bovine rotaviruses. The VP7 and VP4 genes of FRV537 formed a lineage with typical bovine rotaviruses with high bootstrap values. As to the internal capsid and nonstructural gene constellation, three bovine rotavirus strains had a constellation identical to that of FRV537. Moreover, each of the genotypes of FRV537 was found to be a common bovine genotype. In addition to the high nucleotide sequence identities between FRV537 and bovine rotaviruses in each genome segment (≥95%), phylogenetic analysis revealed a close relationship to bovine/artiodactyl rotaviruses. Thus, the molecular and phylogenetic evidence suggests that FRV537 isolated from a stray cat was of bovine rotavirus origin.

  13. Nociceptor beta II, delta, and epsilon isoforms of PKC differentially mediate paclitaxel-induced spontaneous and evoked pain.

    PubMed

    He, Ying; Wang, Zaijie Jim

    2015-03-18

    As one of the most effective and frequently used chemotherapeutic agents, paclitaxel produces peripheral neuropathy (paclitaxel-induced peripheral neuropathy or PIPN) that negatively affects chemotherapy and persists after cancer therapy. The mechanisms underlying this dose-limiting side effect remain to be fully elucidated. This study aimed to investigate the role of nociceptor protein kinase C (PKC) isoforms in PIPN. Employing multiple complementary approaches, we have identified a subset of PKC isoforms, namely βII, δ, and ϵ, were activated by paclitaxel in the isolated primary afferent sensory neurons. Persistent activation of PKCβII, PKCδ, and PKCϵ was also observed in the dorsal root ganglion neurons after chronic treatment with paclitaxel in a mouse model of PIPN. Isoform-selective inhibitors of PKCβII, PKCδ, and PKCϵ given intrathecally dose-dependently attenuated paclitaxel-induced mechanical allodynia and heat hyperalgesia. Surprisingly, spinal inhibition of PKCβII and PKCδ, but not PKCϵ, blocked the spontaneous pain induced by paclitaxel. These data suggest that a subset of nociceptor PKC isoforms differentially contribute to spontaneous and evoked pain in PIPN, although it is not clear whether PKCϵ in other regions regulates spontaneous pain in PIPN. The findings can potentially offer new selective targets for pharmacological intervention of PIPN.

  14. Temporal expression and mitochondrial localization of a Foxp2 isoform lacking the forkhead domain in developing Purkinje cells.

    PubMed

    Tanabe, Yuko; Fujiwara, Yuji; Matsuzaki, Ayumi; Fujita, Eriko; Kasahara, Tadashi; Yuasa, Shigeki; Momoi, Takashi

    2012-07-01

    FOXP2, a forkhead box-containing transcription factor, forms homo- or hetero-dimers with FOXP family members and localizes to the nucleus, while FOXP2(R553H), which contains a mutation related to speech/language disorders, features reduced DNA binding activity and both cytoplasmic and nuclear localization. In addition to being a loss-of-function mutation, it is possible that FOXP2(R553H) also may act as a gain-of-function mutation to inhibit the functions of FOXP2 isoforms including FOXP2Ex10+ lacking forkhead domain. Foxp2(R552H) knock-in mouse pups exhibit impaired ultrasonic vocalization and poor dendritic development in Purkinje cells. However, expressions of Foxp2 isoforms in the developing Purkinje are unclear. The appearance of 'apical cytoplasmic swelling' (mitochondria-rich regions that are the source of budding processes) correlates with dendritic development of Purkinje cells. In the present study, we focused on Foxp2 isoforms localizing to the apical cytoplasmic swelling and identified two isoforms lacking forkhead domain: Foxp2Ex12+ and Foxp2Ex15. They partly localized to the membrane fraction that includes mitochondria. Foxp2Ex12+ mainly localized to the apical cytoplasmic swelling in early developing Purkinje cells at the stellate stage (P2-P4). Mitochondrial localization of Foxp2Ex12+ in Purkinje cells was confirmed by immune-electron microscopic analysis. Foxp2Ex12+ may play a role in dendritic development in Purkinje cells.

  15. Constitutive nuclear localization of an alternatively spliced sirtuin-2 isoform.

    PubMed

    Rack, Johannes G M; VanLinden, Magali R; Lutter, Timo; Aasland, Rein; Ziegler, Mathias

    2014-04-17

    Sirtuin-2 (SIRT2), the cytoplasmic member of the sirtuin family, has been implicated in the deacetylation of nuclear proteins. Although the enzyme has been reported to be located to the nucleus during G2/M phase, its spectrum of targets suggests functions in the nucleus throughout the cell cycle. While a nucleocytoplasmic shuttling mechanism has been proposed for SIRT2, recent studies have indicated the presence of a constitutively nuclear isoform. Here we report the identification of a novel splice variant (isoform 5) of SIRT2 that lacks a nuclear export signal and encodes a predominantly nuclear isoform. This novel isoform 5 fails to show deacetylase activity using several assays, both in vitro and in vivo, and we are led to conclude that this isoform is catalytically inactive. Nevertheless, it retains the ability to interact with p300, a known interaction partner. Moreover, changes in intrinsic tryptophan fluorescence upon denaturation indicate that the protein is properly folded. These data, together with computational analyses, confirm the structural integrity of the catalytic domain. Our results suggest an activity-independent nuclear function of the novel isoform.

  16. Cell-specific expression of TLR9 isoforms in inflammation.

    PubMed

    McKelvey, Kelly J; Highton, John; Hessian, Paul A

    2011-02-01

    Toll-like receptors (TLRs) are key pattern recognition receptors during an immune response. With five isoforms of human TLR9 described, we hypothesised that differential expression of TLR9 isoforms in different cell types would result in variable contributions to the overall input from TLR9 during inflammation. We assessed the molecular expression of the TLR9 isoforms, TLR9-A, -C and -D. In normal peripheral blood mononuclear cells, B-lymphocytes express ∼100-fold more TLR9-A transcript than monocytes or T-lymphocytes, which predominantly express the TLR9-C transcript. Switches in isoform predominance accompany B-lymphocyte development. TLR9 protein expression in rheumatoid inflammatory lesions reflected the TLR9 isoform expression by immune cells. Herein we suggest that B-lymphocytes and plasmacytoid dendritic cells contribute the ∼3-fold higher TLR9-A transcript levels observed in inflamed synovium when compared to subcutaneous rheumatoid nodules. In contrast, macrophages and T-lymphocytes contribute the ∼4-fold higher TLR9-C transcript levels seen in nodules, compared to synovia. From protein sequence, predictions of subcellular localisation suggest TLR9-B may locate to the mitochondria, whereas TLR9-D adopts an opposing orientation in the endoplasmic reticulum. Consistent with this, structure models raise the possibility of alternative ligands for the TLR9-B and TLR9-D variants. Our results highlight differences in the expression of human TLR9 isoforms in normal and inflamed tissues, with differing contributions to inflammation.

  17. MITA/STING and Its Alternative Splicing Isoform MRP Restrict Hepatitis B Virus Replication.

    PubMed

    Liu, Shuhui; Zhao, Kaitao; Su, Xi; Lu, Lu; Zhao, He; Zhang, Xianwen; Wang, Yun; Wu, Chunchen; Chen, Jizheng; Zhou, Yuan; Hu, Xue; Wang, Yanyi; Lu, Mengji; Chen, Xinwen; Pei, Rongjuan

    2017-01-01

    An efficient clearance of hepatitis B virus (HBV) requires the coordinated work of both the innate and adaptive immune responses. MITA/STING, an adapter protein of the innate immune signaling pathways, plays a key role in regulating innate and adaptive immune responses to DNA virus infection. Previously, we identified an alternatively spliced isoform of MITA/STING, called MITA-related protein (MRP), and found that MRP could specifically block MITA-mediated interferon (IFN) induction while retaining the ability to activate NF-κB. Here, we asked whether MITA/STING and MRP were able to control the HBV replication. Both MITA/STING and MRP significantly inhibited HBV replication in vitro. MITA overexpression stimulated IRF3-IFN pathway; while MRP overexpression activated NF-κB pathway, suggesting these two isoforms may inhibit HBV replication through different ways. Using a hydrodynamic injection (HI) mouse model, we found that HBV replication was reduced following MITA/STING and MRP expression vectors in mice and was enhanced by the knockout of MITA/STING (MITA/STING-/-). The HBV specific humoral and CD8+ T cell responses were impaired in MITA/STING deficient mice, suggesting the participation of MITA/STING in the initiation of host adaptive immune responses. In summary, our data suggest that MITA/STING and MRP contribute to HBV control via modulation of the innate and adaptive responses.

  18. MITA/STING and Its Alternative Splicing Isoform MRP Restrict Hepatitis B Virus Replication

    PubMed Central

    Liu, Shuhui; Zhao, Kaitao; Su, Xi; Lu, Lu; Zhao, He; Zhang, Xianwen; Wang, Yun; Wu, Chunchen; Chen, Jizheng; Zhou, Yuan; Hu, Xue; Wang, Yanyi; Lu, Mengji; Chen, Xinwen; Pei, Rongjuan

    2017-01-01

    An efficient clearance of hepatitis B virus (HBV) requires the coordinated work of both the innate and adaptive immune responses. MITA/STING, an adapter protein of the innate immune signaling pathways, plays a key role in regulating innate and adaptive immune responses to DNA virus infection. Previously, we identified an alternatively spliced isoform of MITA/STING, called MITA-related protein (MRP), and found that MRP could specifically block MITA-mediated interferon (IFN) induction while retaining the ability to activate NF-κB. Here, we asked whether MITA/STING and MRP were able to control the HBV replication. Both MITA/STING and MRP significantly inhibited HBV replication in vitro. MITA overexpression stimulated IRF3-IFN pathway; while MRP overexpression activated NF-κB pathway, suggesting these two isoforms may inhibit HBV replication through different ways. Using a hydrodynamic injection (HI) mouse model, we found that HBV replication was reduced following MITA/STING and MRP expression vectors in mice and was enhanced by the knockout of MITA/STING (MITA/STING-/-). The HBV specific humoral and CD8+ T cell responses were impaired in MITA/STING deficient mice, suggesting the participation of MITA/STING in the initiation of host adaptive immune responses. In summary, our data suggest that MITA/STING and MRP contribute to HBV control via modulation of the innate and adaptive responses. PMID:28056087

  19. TREK-1 isoforms generated by alternative translation initiation display different susceptibility to the antidepressant fluoxetine.

    PubMed

    Eckert, Michaela; Egenberger, Brigitte; Döring, Frank; Wischmeyer, Erhard

    2011-01-01

    Two-pore-domain K(+) (K(2)P) channels are highly expressed in neurons and cardiac myocytes. In this study we investigated the potency of the antidepressant fluoxetine to inhibit brain and cardiac K(2)P channels, TREK-1, TASK-1 and THIK-1. Maximal sensitivity was detected for TREK-1, which was inhibited by 77% when expressed in HEK-293 cells and Xenopus oocytes. Alternative translation initiation (ATI) generates two different protein products from a single transcript of TREK-1. Electrophysiological analysis of two polypeptides engineered by mutagenesis (TREK-1[M53I], TREK-1[ΔN52]) revealed reduced current amplitude and K(+) selectivity of the truncated TREK-1 isoform. The sensitivity of TREK-1[ΔN52] to fluoxetine decreased by 70%, indicating that the first 52 amino acids are essential for TREK-1 sensitivity to this drug.

  20. Lacrimal gland PKC isoforms are differentially involved in agonist-induced protein secretion.

    PubMed

    Zoukhri, D; Hodges, R R; Sergheraert, C; Toker, A; Dartt, D A

    1997-01-01

    In the present study, we have synthesized and N-myristoylated peptides derived from the pseudosubstrate sequences of protein kinase C (PKC)-alpha, -delta, and -epsilon [Myr-PKC-alpha-(15-28), Myr-PKC-delta-(142-153), and Myr-PKC-epsilon-(149-164)], three isoforms present in rat lacrimal gland, and a peptide derived from the sequence of the endogenous inhibitor of protein kinase A [Myr-PKI-(17-25)]. Lacrimal gland acini were preincubated for 60 min with the myristoylated peptides (10(-10) to 3 x 10(-7) M), then protein secretion was stimulated with a phorbol ester, phorbol 12,13-dibutyrate (10(-6) M); vasoactive intestinal peptide (10(-8) M); a cholinergic agonist, carbachol (10(-5) M); or an alpha 1-adrenergic agonist, phenylephrine (10(-4) M), for 20 min. In intact lacrimal gland acini, Myr-PKC-alpha-(15-28) inhibited phorbol 12,13-dibutyrate-induced protein secretion. This effect was not reproduced by the acetylated peptide or by the myristoylated PKI, which inhibited vasoactive intestinal peptide-induced protein secretion, a response mediated by protein kinase A. Carbachol-induced protein secretion was inhibited by all three peptides. In contrast, phenylephrine-induced protein secretion was inhibited only by Myr-PKC-epsilon-(149-164), whereas Myr-PKC-alpha-(15-28) and Myr-PKC-delta-(142-153) had a stimulatory effect. None of these myristoylated peptides affected the calcium increase evoked by cholinergic or alpha 1-adrenergic agonists. We concluded that phorbol ester- and receptor-induced protein secretion involve different PKC isoforms in lacrimal gland.

  1. Regulation of PGC-1α Isoform Expression in Skeletal Muscles

    PubMed Central

    Popov, D. V.; Lysenko, E. A.; Kuzmin, I. V.; Vinogradova, Vinogradova; Grigoriev, A. I.

    2015-01-01

    The coactivator PGC-1α is the key regulator of mitochondrial biogenesis in skeletal muscle. Skeletal muscle expresses several PGC-1α isoforms. This review covers the functional role of PGC-1α isoforms and the regulation of their exercise-associated expression in skeletal muscle. The patterns of PGC-1α mRNA expression may markedly differ at rest and after muscle activity. Different signaling pathways are activated by different physiological stimuli, which regulate the expression of the PGC-1α gene from the canonical and alternative promoters: expression from a canonical (proximal) promoter is regulated by activation of the AMPK; expression from an alternative promoter, via a β2-adrenergic receptor. All transcripts from both promoters are subject to alternative splicing. As a result, truncated isoforms that possess different properties are translated: truncated isoforms are more stable and predominantly activate angiogenesis, whereas full-length isoforms manly regulate mitochondrial biogenesis. The existence of several isoforms partially explains the broad-spectrum function of this protein and allows the organism to adapt to different physiological stimuli. Regulation of the PGC-1α gene expression by different signaling pathways provides ample opportunity for pharmacological influence on the expression of this gene. Those opportunities might be important for the treatment and prevention of various diseases, such as metabolic syndrome and diabetes mellitus. Elucidation of the regulatory mechanisms of the PGC-1α gene expression and their functional role may provide an opportunity to control the expression of different isoforms through exercise and/or pharmacological intervention. PMID:25927001

  2. Insulin Receptor Isoform Variations in Prostate Cancer Cells

    PubMed Central

    Perks, Claire M.; Zielinska, H. A.; Wang, Jing; Jarrett, Caroline; Frankow, A.; Ladomery, Michael R.; Bahl, Amit; Rhodes, Anthony; Oxley, Jon; Holly, Jeff M. P.

    2016-01-01

    Men who develop prostate cancer (PCa) increasingly have one of the co-morbidities associated with a Western lifestyle that are characterized by hyperinsulinemia, hyperglycemia and increased expression of insulin-like growth factors-I (IGF-I) and IGF-II. Each have been associated with poor prognosis and more aggressive cancers that exhibit increased metabolism and increased glucose uptake. The insulin receptor (IR) has two splice isoforms IR-A and IR-B: IR-A has a higher affinity for IGF-II comparable to that for insulin, whereas the IR-B isoform predominantly just binds to insulin. In this study, we assessed alterations in the IR-A and IR-B isoform ratio and associated changes in cell proliferation and migration of PCa cell lines following exposure to altered concentrations of glucose and treatment with IGF-II and insulin. We observed that where IR-B predominated insulin had a greater effect on migration than IGF-II and IGF-II was more effective when IR-A was the main isoform. With regard to proliferation IGF-II was more effective than insulin regardless of which isoform was dominant. We assessed the abundance of the IR isoforms both in vivo and in vitro and observed that the majority of the tissue samples and cell lines expressed more IR-A than IR-B. Alterations in the isoforms in response to changes in their hormonal milieu could have a profound impact on how malignant cells behave and play a role in promoting carcinogenesis. A greater understanding of the mechanisms underlying changes in alternative splicing of the IR may provide additional targets for future cancer therapies. PMID:27733843

  3. Characterization of the Igf-II Binding Site of the IGF-II/MAN-6-P Receptor Extracellular Domain.

    NASA Astrophysics Data System (ADS)

    Garmroudi, Farideh

    1995-01-01

    In mammals, insulin-like growth factor II (IGF -II) and glycoproteins bearing the mannose 6-phosphate (Man -6-P) recognition marker bind with high affinity to the same receptor. The functional consequences of IGF-II binding to the receptor at the cell surface are not clear. In these studies, we sought to broaden our understanding of the functional regions of the receptor regarding its IGF -II binding site. The IGF-II binding/cross-linking domain of the IGF-II/Man-6-P receptor was mapped by sequencing receptor fragments covalently attached to IGF-II. Purified rat placental or bovine liver receptors were affinity-labeled, with ^{125}I-IGF-II and digested with endoproteinase Glu-C. Analysis of digests by gel electrophoresis revealed a major radiolabeled band of 18 kDa, which was purified by gel filtration chromatography followed by reverse-phase HPLC and electroblotting. Sequence analysis revealed that, the peptide S(H)VNSXPMF, located within extracellular repeat 10 and beginning with serine 1488 of the bovine receptor, was the best candidate for the IGF-II cross-linked peptide. These data indicated that residues within repeats 10-11 were important for IGF -II binding. To define the location of the IGF-II binding site further, a nested set of six human receptor cDNA constructs was designed to produce epitope-tagged fusion proteins encompassing the region between repeats 8 and 11 of the human IGF-II/Man-6-P receptor extracellular domain. These truncated receptors were transiently expressed in COS-7 cells, immunoprecipitated and analyzed for their abilities to bind and cross-link to IGF-II. All of the constructs were capable of binding/cross-linking to IGF-II, except for the 9.0-11 construct. Displacement curve analysis indicated that the truncated receptors were approximately equivalent in IGF-II binding affinity, but were of 5- to 10-fold lower affinity than full-length receptors. Sequencing of the 9.0-11 construct indicated the presence of a point mutation

  4. New insights into the risk of phthalates: Inhibition of UDP-glucuronosyltransferases.

    PubMed

    Liu, Xin; Cao, Yun-Feng; Ran, Rui-Xue; Dong, Pei-Pei; Gonzalez, Frank J; Wu, Xue; Huang, Ting; Chen, Jian-Xin; Fu, Zhi-Wei; Li, Rong-Shan; Liu, Yong-Zhe; Sun, Hong-Zhi; Fang, Zhong-Ze

    2016-02-01

    Wide utilization of phthalates-containing products results in the significant exposure of humans to these compounds. Many adverse effects of phthalates have been documented in rodent models, but their effects in humans exposed to these chemicals remain unclear until more mechanistic studies on phthalate toxicities can be carried out. To provide new insights to predict the potential adverse effects of phthalates in humans, the recent study investigated the inhibition of representative phthalates di-n-octyl ortho-phthalate (DNOP) and diphenyl phthalate (DPhP) towards the important xenobiotic and endobiotic-metabolizing UDP-glucuronosyltransferases (UGTs). An in vitro UGTs incubation system was employed to study the inhibition of DNOP and DPhP towards UGT isoforms. DPhP and DNOP weakly inhibited the activities of UGT1A1, UGT1A7, and UGT1A8. 100 µM of DNOP inhibited the activities of UGT1A3, UGT1A9, and UGT2B7 by 41.8% (p < 0.01), 45.6% (p < 0.01), and 48.8% (p < 0.01), respectively. 100 µM of DPhP inhibited the activity of UGT1A3, UGT1A6, and UGT1A9 by 81.8 (p < 0.001), 49.1% (p < 0.05), and 76.4% (p < 0.001), respectively. In silico analysis was used to explain the stronger inhibition of DPhP than DNOP towards UGT1A3 activity. Kinetics studies were carried our to determine mechanism of inhibition of UGT1A3 by DPhP. Both Dixon and Lineweaver-Burk plots showed the competitive inhibition of DPhP towards UGT1A3. The inhibition kinetic parameter (Ki) was calculated to be 0.89 µM. Based on the [I]/Ki standard ([I]/Ki < 0.1, low possibility; 1>[I]/Ki > 0.1, medium possibility; [I]/Ki > 1, high possibility), these studies predicted in vivo drug-drug interaction might occur when the plasma concentration of DPhP was above 0.089 µM. Taken together, this study reveales the potential for adverse effects of phthalates DNOP and DPhP as a result of UGT inhibition.

  5. The plasma membrane Ca2+ pump isoform 4a differs from isoform 4b in the mechanism of calmodulin binding and activation kinetics: implications for Ca2+ signaling.

    PubMed

    Caride, Ariel J; Filoteo, Adelaida G; Penniston, John T; Strehler, Emanuel E

    2007-08-31

    The inhibition by the regulatory domain and the interaction with calmodulin (CaM) vary among plasma membrane calcium pump (PMCA) isoforms. To explore these differences, the kinetics of CaM effects on PMCA4a were investigated and compared with those of PMCA4b. The maximal apparent rate constant for CaM activation of PMCA4a was almost twice that for PMCA4b, whereas the rates of activation for both isoforms showed similar dependence on Ca2+. The inactivation of PMCA4a by CaM removal was also faster than for PMCA4b, and Ca2+ showed a much smaller effect (2- versus 30-fold modification). The rate constants of the individual steps that determine the overall rates were obtained from stopped-flow experiments in which binding of TA-CaM was observed by changes in its fluorescence. TA-CaM binds to two conformations of PMCA4a, an "open" conformation with high activity, and a "closed" one with lower activity. Compared with PMCA4b (Penheiter, A. R., Bajzer, Z., Filoteo, A. G., Thorogate, R., Török, K., and Caride, A. J. (2003) Biochemistry 41, 12115-12124), the model for PMCA4a predicts less inhibition in the closed form and a much faster equilibrium between the open and closed forms. Based on the available kinetic parameters, we determined the constants to fit the shape of a Ca2+ signal in PMCA4b-overexpressing Chinese hamster ovary cells. Using the constants for PMCA4a, and allowing small variations in parameters of other systems contributing to a Ca2+ signal, we then simulated the effect of PMCA4a on the shape of a Ca2+ signal in Chinese hamster ovary cells. The results reproduce the published data (Brini, M., Coletto, L., Pierobon, N., Kraev, N., Guerini, D., and Carafoli, E. (2003) J. Biol. Chem. 278, 24500-24508), and thereby demonstrate the importance of altered regulatory kinetics for the different functional properties of PMCA isoforms.

  6. Distinct Properties of the Two Isoforms of CDP-Diacylglycerol Synthase

    PubMed Central

    2015-01-01

    CDP-diacylglycerol synthases (CDS) are critical enzymes that catalyze the formation of CDP-diacylglycerol (CDP-DAG) from phosphatidic acid (PA). Here we show in vitro that the two isoforms of human CDS, CDS1 and CDS2, show different acyl chain specificities for its lipid substrate. CDS2 is selective for the acyl chains at the sn-1 and sn-2 positions, the most preferred species being 1-stearoyl-2-arachidonoyl-sn-phosphatidic acid. CDS1, conversely, shows no particular substrate specificity, displaying similar activities for almost all substrates tested. Additionally, we show that inhibition of CDS2 by phosphatidylinositol is also acyl chain-dependent, with the strongest inhibition seen with the 1-stearoyl-2-arachidonoyl species. CDS1 shows no acyl chain-dependent inhibition. Both CDS1 and CDS2 are inhibited by their anionic phospholipid end products, with phosphatidylinositol-(4,5)-bisphosphate showing the strongest inhibition. Our results indicate that CDS1 and CDS2 could create different CDP-DAG pools that may serve to enrich different phospholipid species with specific acyl chains. PMID:25375833

  7. Hsp70 Isoforms Are Essential for the Formation of Kaposi’s Sarcoma-Associated Herpesvirus Replication and Transcription Compartments

    PubMed Central

    Baquero-Pérez, Belinda; Whitehouse, Adrian

    2015-01-01

    Kaposi’s sarcoma-associated herpesvirus (KSHV) is an oncogenic herpesvirus associated with various AIDS-related malignancies. Like other herpesviruses, multiple processes required for KSHV lytic replication, including viral transcription, viral DNA synthesis and capsid assembly occur in virus-induced intranuclear structures, termed replication and transcription compartments (RTCs). Here we utilised a novel methodology, combining subcellular fractionation and quantitative proteomics, to identify cellular proteins which are recruited to KSHV-induced RTCs and thus play a key role in KSHV lytic replication. We show that several isoforms of the HSP70 chaperone family, Hsc70 and iHsp70, are redistributed from the cytoplasm into the nucleus coinciding with the initial formation of KSHV-induced RTCs. We demonstrate that nuclear chaperone foci are dynamic, initially forming adjacent to newly formed KSHV RTCs, however during later time points the chaperones move within KSHV RTCs and completely co-localise with actively replicating viral DNA. The functional significance of Hsp70 isoforms recruitment into KSHV RTCs was also examined using the specific Hsp70 isoform small molecule inhibitor, VER-155008. Intriguingly, results highlight an essential role of Hsp70 isoforms in the KSHV replication cycle independent of protein stability and maturation. Notably, inhibition of Hsp70 isoforms precluded KSHV RTC formation and RNA polymerase II (RNAPII) relocalisation to the viral genome leading to the abolishment of global KSHV transcription and subsequent viral protein synthesis and DNA replication. These new findings have revealed novel mechanisms that regulate KSHV lytic replication and highlight the potential of HSP70 inhibitors as novel antiviral agents. PMID:26587836

  8. Protein Kinase C isoform epsilon (ε) negatively regulates ADP-induced calcium mobilization and thromboxane generation in platelets

    PubMed Central

    Bynagari-Settipalli, Yamini S; Lakhani, Parth; Jin, Jianguo; Bhavaraju, Kamala; Rico, Mario C.; Kim, Soochong; Woulfe, Donna; Kunapuli, Satya P

    2012-01-01

    Objective Members of Protein Kinase C (PKC) family are shown to positively and negatively regulate platelet activation. Although positive regulatory roles are extensively studied, negative regulatory roles of PKCs are poorly understood. In this study we investigated the mechanism and specific isoforms involved in PKC-mediated negative regulation of ADP-induced functional responses. Methods and Results A pan-PKC inhibitor GF109203X potentiated ADP-induced cPLA2 phosphorylation and thromboxane generation, as well as ERK activation and intracellular calcium (Ca2+i) mobilization, two signaling molecules, upstream of cPLA2 activation. Thus, PKCs inhibit cPLA2 activation by inhibiting ERK and Ca2+i mobilization. Since, the inhibitor of Classical PKC isoforms, GO-6976 did not affect ADP-mediated thromboxane generation, we investigated the role of novel class of PKC isoforms. ADP- induced thromboxane generation, calcium mobilization and ERK phosphorylation were potentiated in PKCε null murine platelets compared to platelets from wild type (WT) littermates. Interestingly, when thromboxane release is blocked, ADP-induced aggregation in PKCε KO and WT was similar, suggesting that PKCε does not affect ADP-induced aggregation directly. PKCε knockout mice exhibited shorter times to occlusion in FeCl3-induced arterial injury model and shorter bleeding times in tail bleeding experiments. Conclusion We conclude that PKCε negatively regulates ADP-induced thromboxane generation in platelets and offers protection against thrombosis. PMID:22362759

  9. The effects of phosphoramidon on the expression of human endothelin-converting enzyme-1 (ECE-1) isoforms.

    PubMed

    Isaka, Daiji; Emoto, Noriaki; Raharjo, Sunu Budhi; Yokoyama, Mitsuhiro; Matsuo, Masafumi

    2003-07-01

    Endothelin-1 (ET-1) is generated from big ET-1 by endothelin converting enzyme-1 (ECE-1). This process is inhibited by phosphoramidon through binding to the catalytic domain of ECE-1. There are four isoforms of human ECE-1 (ECE-1a, ECE-1b, ECE-1c and ECE-1d) which possess a conserved catalytic domain. Interestingly, a recent study has shown that in ECE-1b-transfected CHO cells phosphoramidon increases the expression and activity of ECE-1b. It is not known, however, whether phosphoramidon has similar effects on the expression of other ECE-1 isoforms. To address this point, we have established recombinant CHO cell lines that permanently express either human ECE-1a, ECE-1b or ECE-1c. Incubation of CHO/ECE-1a, -1b, and -1c with phosphoramidon (100 microM) for 16 hours markedly elevated the intracellular expression of ECE-1a and ECE-1b, but not ECE-1c protein, as indicated by Western blotting and immunocytochemistry. These increases appear to be due to inhibition of intracellular degradation of the protein because metabolic labeling followed by immunoprecipitation showed ECE-1a and ECE-1b proteins had prolonged half-lives in the phosphoramidon-treated cells. This is further supported by the finding that ECE-1 mRNA levels were unchanged following phosphoramidon treatment. Taken together, our results demonstrate that phosphoramidon differentially affects the expression of three human ECE-1 isoforms.

  10. Engineering of the pyruvate dehydrogenase bypass in Saccharomyces cerevisiae: role of the cytosolic Mg(2+) and mitochondrial K(+) acetaldehyde dehydrogenases Ald6p and Ald4p in acetate formation during alcoholic fermentation.

    PubMed

    Remize, F; Andrieu, E; Dequin, S

    2000-08-01

    Acetic acid plays a crucial role in the organoleptic balance of many fermented products. We have investigated the factors controlling the production of acetate by Saccharomyces cerevisiae during alcoholic fermentation by metabolic engineering of the enzymatic steps involved in its formation and its utilization. The impact of reduced pyruvate decarboxylase (PDC), limited acetaldehyde dehydrogenase (ACDH), or increased acetoacetyl coenzyme A synthetase (ACS) levels in a strain derived from a wine yeast strain was studied during alcoholic fermentation. In the strain with the PDC1 gene deleted exhibiting 25% of the PDC activity of the wild type, no significant differences were observed in the acetate yield or in the amounts of secondary metabolites formed. A strain overexpressing ACS2 and displaying a four- to sevenfold increase in ACS activity did not produce reduced acetate levels. In contrast, strains with one or two disrupted copies of ALD6, encoding the cytosolic Mg(2+)-activated NADP-dependent ACDH and exhibiting 60 and 30% of wild-type ACDH activity, showed a substantial decrease in acetate yield (the acetate production was 75 and 40% of wild-type production, respectively). This decrease was associated with a rerouting of carbon flux towards the formation of glycerol, succinate, and butanediol. The deletion of ALD4, encoding the mitochondrial K(+)-activated NAD(P)-linked ACDH, had no effect on the amount of acetate formed. In contrast, a strain lacking both Ald6p and Ald4p exhibited a long delay in growth and acetate production, suggesting that Ald4p can partially replace the Ald6p isoform. Moreover, the ald6 ald4 double mutant was still able to ferment large amounts of sugar and to produce acetate, suggesting the contribution of another member(s) of the ALD family.

  11. Lobster (Panulirus argus) hepatopancreatic trypsin isoforms and their digestion efficiency.

    PubMed

    Perera, Erick; Rodríguez-Casariego, Javier; Rodríguez-Viera, Leandro; Calero, Jorge; Perdomo-Morales, Rolando; Mancera, Juan M

    2012-04-01

    It is well known that crustaceans exhibit several isoforms of trypsin in their digestive system. Although the number of known crustacean trypsin isoforms continues increasing, especially those derived from cDNA sequences, the role of particular isoenzymes in digestion remains unknown. Among invertebrates, significant advances in the understanding of the role of multiple trypsins have been made only in insects. Since it has been demonstrated that trypsin isoenzyme patterns (phenotypes) in lobster differ in digestion efficiency, we used this crustacean as a model for assessing the biochemical basis of such differences. We demonstrated that the trypsin isoform known to be present in all individuals of Panulirus argus has a high catalytic efficiency (k(cat)/K(m) ) and is the most reactive toward native proteinaceous substrates, whereas one of the isoforms present in less efficient individuals has a lower k(cat) and a lower k(cat)/K(m), and it is less competent at digesting native proteins. A fundamental question in biology is how genetic differences produce different physiological performances. This work is the first to demonstrate that trypsin phenotypic variation in crustacean protein digestion relies on the biochemical properties of the different isoforms. Results are relevant for understanding trypsin polymorphism and protein digestion in lobster.

  12. Differential expression of serum clusterin isoforms in colorectal cancer.

    PubMed

    Rodríguez-Piñeiro, Ana M; de la Cadena, María Páez; López-Saco, Angel; Rodríguez-Berrocal, Francisco J

    2006-09-01

    Clusterin is an enigmatic protein altered in tumors of colorectal cancer patients. Because there is no information available about serum clusterin regarding this pathology, we applied proteomic techniques to analyze its isoforms in donors and patients. First we separated serum proteins through concanavalin A, obtaining a fraction with non- and O-glycosylated proteins (FI) and a second fraction enriched in N-glycoproteins (FII) wherein clusterin was supposed to elute on the basis of its glycosylation. Surprisingly analysis of the FI fraction revealed the existence of an unexpected and aberrantly N-glycosylated clusterin that was overexpressed in patients and comprised at least five isoforms with different isoelectric points. On the other hand, two-dimensional electrophoretic analysis of the clusterin eluted in FII detected one isoform that was increased and 15 isoforms that were decreased or absent in serum of patients. Finally immunoquantification by slot blot showed that in total serum and in FI the clusterin levels were significantly increased in patients, whereas in FII there was no significant variation. Therefore, serum clusterin and some of its isoforms could have a potential value as colorectal tumor markers and are interesting subjects for biomarker studies.

  13. Opposing roles of glutaminase isoforms in determining glioblastoma cell phenotype.

    PubMed

    Szeliga, Monika; Albrecht, Jan

    2015-09-01

    Glutamine (Gln) and glutamate (Glu) play pivotal roles in the malignant phenotype of brain tumors via multiple mechanisms. Glutaminase (GA, EC 3.5.1.2) metabolizes Gln to Glu and ammonia. Human GA isoforms are encoded by two genes: GLS gene codes for kidney-type isoforms, KGA and GAC, whereas GLS2 codes for liver-type isoforms, GAB and LGA. The expression pattern of both genes in different neoplastic cell lines and tissues implicated that the kidney-type isoforms are associated with cell proliferation, while the liver-type isoforms dominate in, and contribute to the phenotype of quiescent cells. GLS gene has been demonstrated to be regulated by oncogene c-Myc, whereas GLS2 gene was identified as a target gene of p53 tumor suppressor. In glioblastomas (GBM, WHO grade IV), the most aggressive brain tumors, high levels of GLS and only traces or lack of GLS2 transcripts were found. Ectopic overexpression of GLS2 in human glioblastoma T98G cells decreased their proliferation and migration and sensitized them to the alkylating agents often used in the chemotherapy of gliomas. GLS silencing reduced proliferation of glioblastoma T98G cells and strengthen the antiproliferative effect evoked by previous GLS2 overexpression.

  14. p53 isoform profiling in glioblastoma and injured brain.

    PubMed

    Takahashi, R; Giannini, C; Sarkaria, J N; Schroeder, M; Rogers, J; Mastroeni, D; Scrable, H

    2013-06-27

    The tumor suppressor p53 has been found to be the most commonly mutated gene in human cancers; however, the frequency of p53 mutations varies from 10 to 70% across different cancer types. This variability can partly be explained by inactivating mechanisms aside from direct genomic polymorphisms. The p53 gene encodes 12 isoforms, some of which can modulate full-length p53 activity in cancer. In this study, we characterized p53 isoform expression patterns in glioblastoma, gliosis, non-tumor brain and neural progenitor cells by SDS-PAGE, immunoblot, mass spectrometry and reverse transcription-PCR. We found that the most consistently expressed isoform in glioblastoma, Δ40p53, was uniquely expressed in regenerative processes, such as those involving neural progenitor cells and gliosis compared with tumor samples. Isoform profiling of glioblastoma tissues revealed the presence of both Δ40p53 and full-length p53, neither of which were detected in non-tumor cerebral cortex. Upon xenograft propagation of tumors, p53 levels increased. The variability of overall p53 expression and relative levels of isoforms suggest fluctuations in subpopulations of cells with greater or lesser capacity for proliferation, which can change as the tumor evolves under different growth conditions.

  15. Familial glaucoma iridogoniodysplasia maps to a 6p25 region implicated in primary congenital glaucoma and iridogoniodysgenesis anomaly.

    PubMed Central

    Jordan, T; Ebenezer, N; Manners, R; McGill, J; Bhattacharya, S

    1997-01-01

    Familial glaucoma iridogoniodysplasia (FGI) is a form of open-angle glaucoma in which developmental anomalies of the iris and irido-corneal angle are associated with a juvenile-onset glaucoma transmitted as an autosomal dominant trait. A single large family with this disorder was examined for genetic linkage to microsatellite markers. A peak LOD score of 11.63 at a recombination fraction of 0 was obtained with marker D6S967 mapping to chromosome 6p25. Haplotype analysis places the disease gene in a 6.4-cM interval between the markers D6S1713 and D6S1600. Two novel clinical appearances extend the phenotypic range and provide evidence of variable expressivity. The chromosome 6p25 region is now implicated in FGI, primary congenital glaucoma, and iridogoniodysgenesis anomaly. This may indicate the presence of a common causative gene or, alternatively, a cluster of genes involved in eye development/function. Images Figure 2 PMID:9382099

  16. Alternative splicing isoform of T cell factor 4K suppresses the proliferation and metastasis of non-small cell lung cancer cells.

    PubMed

    Fan, Y C; Min, L; Chen, H; Liu, Y L

    2015-10-30

    The Wnt pathway has been implicated in the initiation, progression, and metastasis of lung cancer. T cell factor 4, a member of TCF/LEF family, acts as a transcriptional factor for Wnt pathways in lung cancer. Increasing amounts of evidence have shown that TCF-4 has multiple alternative splicing isoforms with transactivation or transrepression activity toward the Wnt pathway. Here, we found the presence of multiple TCF-4 isoforms in lung cancer cell lines and in normal bronchial epithelial cells. TCF-4K isoform expression was significantly decreased in lung cancer cells compared with normal bronchial epithelial cells and was identified as a transcriptional suppressor of the Wnt pathway in non-small cell lung carcinoma (NSCLC). Overexpression of TCF-4K significantly inhibited the proliferation and migration of NSCLC cells. Collectively, our data indicate that TCF-4K functions as a tumor suppressor in NSCLC by down-regulating the Wnt pathway.

  17. Phylogenetic analysis of a G6P[5] bovine rotavirus strain isolated in a neonatal diarrhea outbreak in a beef cattle herd vaccinated with G6P[1] and G10P[11] genotypes.

    PubMed

    da Silva Medeiros, Thais Neris; Lorenzetti, Elis; Alfieri, Alice Fernandes; Alfieri, Amauri Alcindo

    2015-02-01

    The aim of this study was to perform the molecular characterization of the eleven genes of a G6P[5] bovine group A rotavirus (RVA) strain detected in a diarrhea outbreak from a vaccinated beef cattle herd. The outbreak affected 80 % of calves between 15-30 days old. RVA was identified by RT-PCR in 12 (70.6 %) out of 17 diarrheic fecal samples evaluated. The rotavirus wild-type strain had the genotype constellation G6(IV)-P[5](IX)-I2c-R2-C2-M2-A3-N2-T6-E2e-H3a. This study confirms the importance of homotypic immunity against the bovine RVA P[5] genotype in neonatal diarrhea in cattle herds that are regularly vaccinated against rotaviruses.

  18. Direct interaction of the mouse cytomegalovirus m152/gp40 immunoevasin with RAE-1 isoforms.

    PubMed

    Zhi, Li; Mans, Janet; Paskow, Michael J; Brown, Patrick H; Schuck, Peter; Jonjić, Stipan; Natarajan, Kannan; Margulies, David H

    2010-03-23

    Cytomegaloviruses (CMVs) are ubiquitous species-specific viruses that establish acute, persistent, and latent infections. Both human and mouse CMVs encode proteins that inhibit the activation of natural killer (NK) cells by downregulating cellular ligands for the NK cell activating receptor, NKG2D. The MCMV glycoprotein m152/gp40 downregulates the surface expression of RAE-1 to prevent NK cell control in vivo. So far, it is unclear if there is a direct interaction between m152 and RAE-1 and, if so, if m152 interacts differentially with the five identified RAE-1 isoforms, which are expressed as two groups in MCMV-susceptible or -resistant mouse strains. To address these questions, we expressed and purified the extracellular domains of RAE-1 and m152 and performed size exclusion chromatography binding assays as well as analytical ultracentrifugation and isothermal titration calorimetry to characterize these interactions quantitatively. We further evaluated the role of full-length and naturally glycosylated m152 and RAE-1 in cotransfected HEK293T cells. Our results confirmed that m152 binds RAE-1 directly, relatively tightly (K(d) < 5 microM), and with 1:1 stoichiometry. The binding is quantitatively different depending on particular RAE-1 isoforms, corresponding to the susceptibility to downregulation by m152. A PLWY motif found in RAE-1beta, although contributing to its affinity for m152, does not influence the affinity of RAE-1gamma or RAE-1delta, suggesting that other differences contribute to the RAE-1-m152 interaction. Molecular modeling of the different RAE-1 isoforms suggests a potential site for the m152 interaction.

  19. New brain-specific beta-synuclein isoforms show expression ratio changes in Lewy body diseases.

    PubMed

    Beyer, Katrin; Munoz-Marmol, Ana M; Sanz, Carolina; Marginet-Flinch, Ruth; Ferrer, Isidro; Ariza, Aurelio

    2012-02-01

    Lewy body diseases (LBDs) include dementia with Lewy bodies (DLB) and Parkinson disease (PD). Alpha-synuclein (AS) aggregation is a key event in the pathogenesis of LBDs and beta-synuclein (BS) inhibits AS aggregation in vitro and in vivo. Recently, BS has been shown to interact directly with AS regulating its functionality and preventing its oligomerization, and a molecular subgroup of pure DLB lacks BS in cortical regions. In this study, we characterized four new BS transcript variants and analyzed their expression in neuronal and non-neuronal tissue, and their differential expression in frozen samples of three areas from brains of patients with pure Lewy body pathology (LBP), common LBP, Alzheimer pathology, and of controls. Relative mRNA expression was determined by real-time PCR with neuron-specific enolase 2 and synaptophysin as housekeeping genes, and expression changes were evaluated by the ΔΔCt method. Two main findings are in concordance with earlier studies. First, all BS isoforms are drastically diminished in the cortex of patients with pure LBP that had presented clinically as DLB but not PD with dementia. Second, an important shift of the isoform expression ratio was observed in the temporal cortex of all LBD cases, and the minor isoforms, normally absent in the midbrain, were detected in the caudate nucleus of all DLB samples. Our results provide further evidence for the role of minor transcript variants in the development of complex diseases and provide new insights into the pathogenesis of LBDs that may be important for the understanding of molecular mechanisms involved in these complex diseases.

  20. Melatonin promotes adventitious root regeneration in in vitro shoot tip explants of the commercial sweet cherry rootstocks CAB-6P (Prunus cerasus L.), Gisela 6 (P. cerasus × P. canescens), and MxM 60 (P. avium × P. mahaleb).

    PubMed

    Sarropoulou, Virginia N; Therios, Ioannis N; Dimassi-Theriou, Kortessa N

    2012-01-01

    The objectives of this study were to test the effects of melatonin (N-acetyl-5-methoxytryptamine), a natural compound of edible plants on the rooting of certain commercial sweet cherry rootstocks. Shoot tip explants from previous in vitro cultures of the cherry rootstocks CAB-6P (Prunus cerasus L.), Gisela 6 (P. cerasus × P. canescens), and M × M 60 (P. avium × P. mahaleb) were included in the experiment. The effect of indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) alone or in combination with melatonin was tested concerning their rooting potential. Seven concentrations of melatonin (0, 0.05, 0.1, 0.5, 1, 5, and 10 μM) alone or in combination with 5.71 μM of IAA or 4.92 μM of IBA were tested. For each rootstock, 21 treatments were included. The explants were grown in glass tubes containing 10 mL of substrate. The parameters measured include rooting percentage, number of roots per rooted explant, root length, and callus formation. The data presented in this study show that melatonin has a rooting promoting effect at a low concentration but a growth inhibitory effect at high concentrations. In the absence of auxin, 1 μM melatonin had auxinic response concerning the number and length of roots, but 10 μM melatonin was inhibitory to rooting in all the tested rootstocks. The final conclusion of this experiment is that exogenously applied melatonin acted as a rooting promoter and its action was similar to that of IAA.

  1. An HP1 isoform-specific feedback mechanism regulates Suv39h1 activity under stress conditions.

    PubMed

    Raurell-Vila, Helena; Bosch-Presegue, Laia; Gonzalez, Jessica; Kane-Goldsmith, Noriko; Casal, Carmen; Brown, Jeremy P; Marazuela-Duque, Anna; Singh, Prim B; Serrano, Lourdes; Vaquero, Alejandro

    2017-02-01

    The presence of H3K9me3 and heterochromatin protein 1 (HP1) are hallmarks of heterochromatin conserved in eukaryotes. The spreading and maintenance of H3K9me3 is effected by the functional interplay between the H3K9me3-specific histone methyltransferase Suv39h1 and HP1. This interplay is complex in mammals because the three HP1 isoforms, HP1α, β, and γ, are thought to play a redundant role in Suv39h1-dependent deposition of H3K9me3 in pericentric heterochromatin (PCH). Here, we demonstrate that despite this redundancy, HP1α and, to a lesser extent, HP1γ have a closer functional link to Suv39h1, compared to HP1β. HP1α and γ preferentially interact in vivo with Suv39h1, regulate its dynamics in heterochromatin, and increase Suv39h1 protein stability through an inhibition of MDM2-dependent Suv39h1-K87 polyubiquitination. The reverse is also observed, where Suv39h1 increases HP1α stability compared HP1β and γ. The interplay between Suv39h1 and HP1 isoforms appears to be relevant under genotoxic stress. Specifically, loss of HP1α and γ isoforms inhibits the upregulation of Suv39h1 and H3K9me3 that is observed under stress conditions. Reciprocally, Suv39h1 deficiency abrogates stress-dependent upregulation of HP1α and γ, and enhances HP1β levels. Our work defines a specific role for HP1 isoforms in regulating Suv39h1 function under stress via a feedback mechanism that likely regulates heterochromatin formation.

  2. ACA12 is a deregulated isoform of plasma membrane Ca²⁺-ATPase of Arabidopsis thaliana.

    PubMed

    Limonta, Margherita; Romanowsky, Shawn; Olivari, Claudio; Bonza, Maria Cristina; Luoni, Laura; Rosenberg, Alexa; Harper, Jeffrey F; De Michelis, Maria Ida

    2014-03-01

    Plant auto-inhibited Ca²⁺-ATPases (ACA) are crucial in defining the shape of calcium transients and therefore in eliciting plant responses to various stimuli. Arabidopsis thaliana genome encodes ten ACA isoforms that can be divided into four clusters based on gene structure and sequence homology. While isoforms from clusters 1, 2 and 4 have been characterized, virtually nothing is known about members of cluster 3 (ACA12 and ACA13). Here we show that a GFP-tagged ACA12 localizes at the plasma membrane and that expression of ACA12 rescues the phenotype of partial male sterility of a null mutant of the plasma membrane isoform ACA9, thus providing genetic evidence that ACA12 is a functional plasma membrane-resident Ca²⁺-ATPase. By ACA12 expression in yeast and purification by CaM-affinity chromatography, we show that, unlike other ACAs, the activity of ACA12 is not stimulated by CaM. Moreover, full length ACA12 is able to rescue a yeast mutant deficient in calcium pumps. Analysis of single point ACA12 mutants suggests that ACA12 loss of auto-inhibition can be ascribed to the lack of two acidic residues--highly conserved in other ACA isoforms--localized at the cytoplasmic edge of the second and third transmembrane segments. Together, these results support a model in which the calcium pump activity of ACA12 is primarily regulated by increasing or decreasing mRNA expression and/or protein translation and degradation.

  3. Actin isoform specificity is required for the maintenance of lactation

    PubMed Central

    Weymouth, Nate; Shi, Zengdun; Rockey, Don C.

    2014-01-01

    Smooth muscle α-actin (Acta2) is one of six highly conserved mammalian actin isoforms that appear to exhibit functional redundancy. Nonetheless, we have postulated a specific functional role for the smooth muscle specific isoform. Here, we show that Acta2 deficient mice have a remarkable mammary phenotype such that dams lacking Acta2 are unable to nurse their offspring effectively. The phenotype was rescued in cross fostering experiments with wild type mice, excluding a developmental defect in Acta2 null pups. The mechanism for the underlying phenotype is due to myoepithelial dysfunction postpartum resulting in precocious involution. Further, we demonstrate a specific defect in myoepithelial cell contractility in Acta2 null mammary glands, despite normal expression of cytoplasmic actins. We conclude that Acta2 specifically mediates myoepithelial cell contraction during lactation and that this actin isoform therefore exhibits functional specificity. PMID:22123032

  4. Laminin isoforms in endothelial and perivascular basement membranes.

    PubMed

    Yousif, Lema F; Di Russo, Jacopo; Sorokin, Lydia

    2013-01-01

    Laminins, one of the major functional components of basement membranes, are found underlying endothelium, and encasing pericytes and smooth muscle cells in the vessel wall. Depending on the type of blood vessel (capillary, venule, postcapillary venule, vein or artery) and their maturation state, both the endothelial and mural cell phenotype vary, with associated changes in laminin isoform expression. Laminins containing the α4 and α5 chains are the major isoforms found in the vessel wall, with the added contribution of laminin α2 in larger vessels. We here summarize current data on the precise localization of these laminin isoforms and their receptors in the different layers of the vessel wall, and their potential contribution to vascular homeostasis.

  5. The Allosterically Unregulated Isoform of ADP-Glucose Pyrophosphorylase from Barley Endosperm Is the Most Likely Source of ADP-Glucose Incorporated into Endosperm Starch.

    PubMed

    Doan; Rudi; Olsen

    1999-11-01

    We present the results of studies of an unmodified version of the recombinant major barley (Hordeum vulgare) endosperm ADP-glucose pyrophoshorylase (AGPase) expressed in insect cells, which corroborate previous data that this isoform of the enzyme acts independently of the allosteric regulators 3-phosphoglycerate and inorganic phosphate. We also present a characterization of the individual subunits expressed separately in insect cells, showing that the SS AGPase is active in the presence of 3-phosphoglycerate and is inhibited by inorganic phosphate. As a step toward the elucidation of the role of the two AGPase isoforms in barley, the temporal and spatial expression profile of the four barley AGPase transcripts encoding these isoforms were studied. The results show that the steady-state level of beps and bepl, the transcripts encoding the major endosperm isoform, correlated positively with the rate of endosperm starch accumulation. In contrast, blps and blpl, the transcripts encoding the major leaf isoform, were constitutively expressed at a very low steady-state level throughout the barley plant. The implications of these findings for the evolution of plant AGPases are discussed.

  6. The Allosterically Unregulated Isoform of ADP-Glucose Pyrophosphorylase from Barley Endosperm Is the Most Likely Source of ADP-Glucose Incorporated into Endosperm Starch1

    PubMed Central

    Doan, Danny N.P.; Rudi, Heidi; Olsen, Odd-Arne

    1999-01-01

    We present the results of studies of an unmodified version of the recombinant major barley (Hordeum vulgare) endosperm ADP-glucose pyrophoshorylase (AGPase) expressed in insect cells, which corroborate previous data that this isoform of the enzyme acts independently of the allosteric regulators 3-phosphoglycerate and inorganic phosphate. We also present a characterization of the individual subunits expressed separately in insect cells, showing that the SS AGPase is active in the presence of 3-phosphoglycerate and is inhibited by inorganic phosphate. As a step toward the elucidation of the role of the two AGPase isoforms in barley, the temporal and spatial expression profile of the four barley AGPase transcripts encoding these isoforms were studied. The results show that the steady-state level of beps and bepl, the transcripts encoding the major endosperm isoform, correlated positively with the rate of endosperm starch accumulation. In contrast, blps and blpl, the transcripts encoding the major leaf isoform, were constitutively expressed at a very low steady-state level throughout the barley plant. The implications of these findings for the evolution of plant AGPases are discussed. PMID:10557246

  7. Purification of a new isoform of laccase from a Marasmius quercophilus strain isolated from a cork oak litter (Quercus suber L).

    PubMed

    Farnet, A M; Criquet, S; Pocachard, E; Gil, G; Ferre, E

    2002-01-01

    A new isoform of laccase from Marasmius quercophilus is described in this study. The strain of this white-rot fungus was isolated for the first time on a cork oak litter. This isoform exhibited certain common properties of laccases (a molecular weight of 65 Kda, an optimum pH of 6.2 with syringaldazine). But this laccase has also particularly novel features: the best activity measured was observed at high temperatures (80 C) and this isoform was not inhibited with EDTA. Furthermore, this induced laccase was able to transform most of the aromatic compounds tested without the addition of mediators to the reaction mixture, and the transformation of certain chlorophenols (2-chlorophenol and 2,4-dichlorophenol) by a laccase isoform from M. quercophilus is reported here for the first time. We also demonstrate the importance of 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate) (ABTS) as a mediator since it allowed veratryl alcohol and p-hydroxybenzoic acid transformation. Moreover, new products of transformation were observed using the combination of ABTS with this isoform of laccase.

  8. A novel a-factor-related peptide of Saccharomyces cerevisiae that exits the cell by a Ste6p-independent mechanism.

    PubMed Central

    Chen, P; Choi, J D; Wang, R; Cotter, R J; Michaelis, S

    1997-01-01

    Many secreted signaling molecules are synthesized as precursors that undergo multiple maturation steps to generate their mature forms. The Saccharomyces cerevisiae mating pheromone a-factor is a C-terminally isoprenylated and carboxylmethylated dodecapeptide that is initially synthesized as a larger precursor containing 36 or 38 amino acids. We have previously shown that the maturation of a-factor occurs by an ordered biogenesis pathway involving 1) three C-terminal modification steps, 2) two N-terminal proteolytic processing events, and 3) a nonclassical export mechanism mediated by the ATP-binding-cassette (ABC) transporter Ste6p. In the present study, we demonstrate that an unexpected and abundant a-factor-related peptide (AFRP) exists in the culture fluid of MATa cells and that its biogenesis is integrally related to that of mature a-factor itself. We show by purification followed by mass spectrometry that AFRP corresponds to the C-terminal 7 amino acids (VFWDPAC) of mature a-factor (YIIKGVFWDPAC), including both the farnesyl- and carboxylmethylcysteine modifications. The formation and export of AFRP displays three striking features. First, we show that AFRP is produced intracellularly and that mutants (ste24 and axl1) that cannot produce mature a-factor due to an N-terminal processing defect are nevertheless normal for AFRP production. Thus, AFRP is not derived from mature a-factor but, instead, from the P1 form of the a-factor precursor. Second, fusion constructs with foreign amino acids substituted for authentic a-factor residues still yield AFRP-sized molecules; however, the composition of these corresponds to the altered residues instead of to AFRP residues. Thus, AFRP may be generated by a sequence-dependent but length-specific proteolytic activity. Third, a-factor and AFRP use distinct cellular machinery for their secretion. Whereas a-factor export is Ste6p-dependent, AFRP is secreted normally even in a ste6 deletion mutant. Thus, AFRP may exit the cell

  9. Autocrine VEGF Isoforms Differentially Regulate Endothelial Cell Behavior

    PubMed Central

    Yamamoto, Hideki; Rundqvist, Helene; Branco, Cristina; Johnson, Randall S.

    2016-01-01

    Vascular endothelial growth factor A (VEGF) is involved in all the essential biology of endothelial cells, from proliferation to vessel function, by mediating intercellular interactions and monolayer integrity. It is expressed as three major alternative spliced variants. In mice, these are VEGF120, VEGF164, and VEGF188, each with different affinities for extracellular matrices and cell surfaces, depending on the inclusion of heparin-binding sites, encoded by exons 6 and 7. To determine the role of each VEGF isoform in endothelial homeostasis, we compared phenotypes of primary endothelial cells isolated from lungs of mice expressing single VEGF isoforms in normoxic and hypoxic conditions. The differential expression and distribution of VEGF isoforms affect endothelial cell functions, such as proliferation, adhesion, migration, and integrity, which are dependent on the stability of and affinity to VEGF receptor 2 (VEGFR2). We found a correlation between autocrine VEGF164 and VEGFR2 stability, which is also associated with increased expression of proteins involved in cell adhesion. Endothelial cells expressing only VEGF188, which localizes to extracellular matrices or cell surfaces, presented a mesenchymal morphology and weakened monolayer integrity. Cells expressing only VEGF120 lacked stable VEGFR2 and dysfunctional downstream processes, rendering the cells unviable. Endothelial cells expressing these different isoforms in isolation also had differing rates of apoptosis, proliferation, and signaling via nitric oxide (NO) synthesis. These data indicate that autocrine signaling of each VEGF isoform has unique functions on endothelial homeostasis and response to hypoxia, due to both distinct VEGF distribution and VEGFR2 stability, which appears to be, at least partly, affected by differential NO production. This study demonstrates that each autocrine VEGF isoform has a distinct effect on downstream functions, namely VEGFR2-regulated endothelial cell homeostasis in

  10. Oxygenation properties and isoform diversity of snake hemoglobins

    PubMed Central

    Natarajan, Chandrasekhar; Moriyama, Hideaki; Hoffmann, Federico G.; Wang, Tobias; Fago, Angela; Malte, Hans; Overgaard, Johannes; Weber, Roy E.

    2015-01-01

    Available data suggest that snake hemoglobins (Hbs) are characterized by a combination of unusual structural and functional properties relative to the Hbs of other amniote vertebrates, including oxygenation-linked tetramer-dimer dissociation. However, standardized comparative data are lacking for snake Hbs, and the Hb isoform composition of snake red blood cells has not been systematically characterized. Here we present the results of an integrated analysis of snake Hbs and the underlying α- and β-type globin genes to characterize 1) Hb isoform composition of definitive erythrocytes, and 2) the oxygenation properties of isolated isoforms as well as composite hemolysates. We used species from three families as subjects for experimental studies of Hb function: South American rattlesnake, Crotalus durissus (Viperidae); Indian python, Python molurus (Pythonidae); and yellow-bellied sea snake, Pelamis platura (Elapidae). We analyzed allosteric properties of snake Hbs in terms of the Monod-Wyman-Changeux model and Adair four-step thermodynamic model. Hbs from each of the three species exhibited high intrinsic O2 affinities, low cooperativities, small Bohr factors in the absence of phosphates, and high sensitivities to ATP. Oxygenation properties of the snake Hbs could be explained entirely by allosteric transitions in the quaternary structure of intact tetramers, suggesting that ligation-dependent dissociation of Hb tetramers into αβ-dimers is not a universal feature of snake Hbs. Surprisingly, the major Hb isoform of the South American rattlesnake is homologous to the minor HbD of other amniotes and, contrary to the pattern of Hb isoform differentiation in birds and turtles, exhibits a lower O2 affinity than the HbA isoform. PMID:26354849

  11. Oxygenation properties and isoform diversity of snake hemoglobins.

    PubMed

    Storz, Jay F; Natarajan, Chandrasekhar; Moriyama, Hideaki; Hoffmann, Federico G; Wang, Tobias; Fago, Angela; Malte, Hans; Overgaard, Johannes; Weber, Roy E

    2015-11-01

    Available data suggest that snake hemoglobins (Hbs) are characterized by a combination of unusual structural and functional properties relative to the Hbs of other amniote vertebrates, including oxygenation-linked tetramer-dimer dissociation. However, standardized comparative data are lacking for snake Hbs, and the Hb isoform composition of snake red blood cells has not been systematically characterized. Here we present the results of an integrated analysis of snake Hbs and the underlying α- and β-type globin genes to characterize 1) Hb isoform composition of definitive erythrocytes, and 2) the oxygenation properties of isolated isoforms as well as composite hemolysates. We used species from three families as subjects for experimental studies of Hb function: South American rattlesnake, Crotalus durissus (Viperidae); Indian python, Python molurus (Pythonidae); and yellow-bellied sea snake, Pelamis platura (Elapidae). We analyzed allosteric properties of snake Hbs in terms of the Monod-Wyman-Changeux model and Adair four-step thermodynamic model. Hbs from each of the three species exhibited high intrinsic O2 affinities, low cooperativities, small Bohr factors in the absence of phosphates, and high sensitivities to ATP. Oxygenation properties of the snake Hbs could be explained entirely by allosteric transitions in the quaternary structure of intact tetramers, suggesting that ligation-dependent dissociation of Hb tetramers into αβ-dimers is not a universal feature of snake Hbs. Surprisingly, the major Hb isoform of the South American rattlesnake is homologous to the minor HbD of other amniotes and, contrary to the pattern of Hb isoform differentiation in birds and turtles, exhibits a lower O2 affinity than the HbA isoform.

  12. Identification and characterization of novel NuMA isoforms

    SciTech Connect

    Wu, Jin; Xu, Zhe; He, Dacheng; Lu, Guanting

    2014-11-21

    Highlights: • Seven NuMA isoforms generated by alternative splicing were categorized into 3 groups: long, middle and short. • Both exons 15 and 16 in long NuMA were “hotspot” for alternative splicing. • Lower expression of short NuMA was observed in cancer cells compared with nonneoplastic controls. • Distinct localization pattern of short isoforms indicated different function from that of long and middle NuMA. - Abstract: The large nuclear mitotic apparatus (NuMA) has been investigated for over 30 years with functions related to the formation and maintenance of mitotic spindle poles during mitosis. However, the existence and functions of NuMA isoforms generated by alternative splicing remains unclear. In the present work, we show that at least seven NuMA isoforms (categorized into long, middle and short groups) generated by alternative splicing from a common NuMA mRNA precursor were discovered in HeLa cells and these isoforms differ mainly at the carboxyl terminus and the coiled-coil domains. Two “hotspot” exons with molecular mass of 3366-nt and 42-nt tend to be spliced during alternative splicing in long and middle groups. Furthermore, full-length coding sequences of long and middle NuMA obtained by using fusion PCR were constructed into GFP-tagged vector to illustrate their cellular localization. Long NuMA mainly localized in the nucleus with absence from nucleoli during interphase and translocated to the spindle poles in mitosis. Middle NuMA displayed the similar cell cycle-dependent distribution pattern as long NuMA. However, expression of NuMA short isoforms revealed a distinct subcellular localization. Short NuMA were present in the cytosol during the whole cycle, without colocalization with mitotic apparatus. These results have allowed us tentatively to explore a new research direction for NuMA’s various functions.

  13. Juvenile myoclonic epilepsy locus in chromosome 6p21.2-p11: Linkage to convulsions and electroencephalography trait

    SciTech Connect

    Liu, A.W.; Delgado-Escueta, A.V.; Serratosa, J.M.

    1995-08-01

    Despite affecting 4 million Americans and 100-200 million persons worldwide, the precise molecular mechanisms of human epilepsies remain unknown. Juvenile myoclonic epilepsy (JME) is the most frequent and, hence, most important form of hereditary grand mal epilepsy. In this epilepsy, electroencephalographic (EEG) 15-30 Hz multispikes produce myoclonic and tonic-clonic convulsions beginning at 8-20 years of age. Moreover, EEG 3.5-6 Hz multispike wave complexes appear in clinically asymptomatic family members. We first studied 38 members of a four-generation LA-Belize family with classical JME but with no pyknoleptic absences. Five living members had JME; four clinically asymptomatic members had EEG multispike wave complexes. Pairwise analysis tightly linked microsatellites centromeric to HLA, namely D6S272 (peak lod score [Z{sub max}]=3.564-3.560 at male-female recombination [{theta}{sub m=f}]=0-0.001) and D6S257 (Z{sub max}=3.672-3.6667 at {theta}{sub m=f}=0-0.001), spanning 7 cM, to convulsive seizures and EEG multispike wave complexes. A recombination between D6S276 and D6S273 in one affected member placed the JME locus within or below HLA. Pairwise, multipoint, and recombination analyses in this large family independently proved that a JME gene is located in chromsome 6p, centromeric to HLA. We next screened, with the same chromosome 6p21.2-p11 short tandem-repeat polymorphic markers, seven multiplex pedigrees with classic JME. When lod scores for small multiplex families are added to lod scores of the LA-Belize pedigree, Z{sub max} values for D6S294 and D6S257 are >7 ({theta}{sub m=f}=0.000). Our results prove that in chromosome 6p21.2-p11 an epilepsy locus exists whose phenotype consists of classic JME with convulsions and/or EEG rapid multispike wave complexes. 31 refs., 6 figs., 4 tabs.

  14. Modulation of neuronal differentiation by CD40 isoforms

    SciTech Connect

    Hou Huayu; Obregon, Demian; Lou, Deyan; Ehrhart, Jared; Fernandez, Frank; Silver, Archie; Tan Jun

    2008-05-02

    Neuron differentiation is a complex process involving various cell-cell interactions, and multiple signaling pathways. We showed previously that CD40 is expressed and functional on mouse and human neurons. In neurons, ligation of CD40 protects against serum withdrawal-induced injury and plays a role in survival and differentiation. CD40 deficient mice display neuron dysfunction, aberrant neuron morphologic changes, and associated gross brain abnormalities. Previous studies by Tone and colleagues suggested that five isoforms of CD40 exist with two predominant isoforms expressed in humans: signal-transducible CD40 type I and a C-terminal truncated, non-signal-transducible CD40 type II. We hypothesized that differential expression of CD40 isoform type I and type II in neurons may modulate neuron differentiation. Results show that adult wild-type, and CD40{sup -/-} deficient mice predominantly express CD40 type I and II isoforms. Whereas adult wild-type mice express mostly CD40 type I in cerebral tissues at relatively high levels, in age and gender-matched CD40{sup -/-} mice CD40 type I expression was almost completely absent; suggesting a predominance of the non-signal-transducible CD40 type II isoform. Younger, 1 day old wild-type mice displayed less CD40 type I, and more CD40 type II, as well as, greater expression of soluble CD40 (CD40L/CD40 signal inhibitor), compared with 1 month old mice. Neuron-like N2a cells express CD40 type I and type II isoforms while in an undifferentiated state, however once induced to differentiate, CD40 type I predominates. Further, differentiated N2a cells treated with CD40 ligand express high levels of neuron specific nuclear protein (NeuN); an effect reduced by anti-CD40 type I siRNA, but not by control (non-targeting) siRNA. Altogether these data suggest that CD40 isoforms may act in a temporal fashion to modulate neuron differentiation during brain development. Thus, modulation of neuronal CD40 isoforms and CD40 signaling may

  15. Ab initio study of neutral and charged SinNap(+) (n 6, p

    PubMed

    Sporea, C; Rabilloud, F; Allouche, A R; Frécon, M

    2006-01-26

    Ab initio calculations in the framework of the density functional theory, with B3LYP functional, are performed to study the lowest-energy isomers of silicon sodium clusters Si(n)Na(p)(+) (n 6, p

  16. Reflections on the evidence for a vulnerability locus for Schizophrenia on chromosome 6p24-22

    SciTech Connect

    Kendler, K.S.; Straub, R.E.; MacLean, C.J.

    1996-04-09

    A recent series of studies have attempted to replicate evidence for a vulnerability locus for schizophrenia on chromosome 6p initially detected in the Irish Study of High-Density Schizophrenia Families (ISHDSF). Here, we want to comment briefly on these findings and respond to some of the issues raised in the preceding article by Baron. We disclaim, however, any pretensions to a definitive interpretation of the available evidence. Our level of ignorance in the interpretation of linkage evidence for complex psychiatric syndromes is too profound. Rather, we seek to make educated guesses on the basis of our understanding of the principles of linkage analysis, on our knowledge of the problems of statistical inference and on our intuition of how genes might influence vulnerability to complex human behavioral traits. 27 refs.

  17. Electron-impact ionization cross sections out of the ground and 6P2 excited states of cesium

    NASA Astrophysics Data System (ADS)

    Łukomski, M.; Sutton, S.; Kedzierski, W.; Reddish, T. J.; Bartschat, K.; Bartlett, P. L.; Bray, I.; Stelbovics, A. T.; McConkey, J. W.

    2006-09-01

    An atom trapping technique for determining absolute, total ionization cross sections (TICS) out of an excited atom is presented. The unique feature of our method is in utilizing Doppler cooling of neutral atoms to determine ionization cross sections. This fluorescence-monitoring experiment, which is a variant of the “trap loss” technique, has enabled us to obtain the experimental electron impact ionization cross sections out of the Cs 6P3/22 state between 7eV and 400eV . CCC, RMPS, and Born theoretical results are also presented for both the ground and excited states of cesium and rubidium. In the low energy region (<11eV) where best agreement between these excited state measurements and theory might be expected, a discrepancy of approximately a factor of five is observed. Above this energy there are significant contributions to the TICS from both autoionization and multiple ionization.

  18. Solvation dynamics of 4-(dicyanomethylene)-2-methyl-6-( p-dimethylaminostyryl)-4H-pyran (DCM) in a microemulsion

    NASA Astrophysics Data System (ADS)

    Pal, Samir Kumar; Mandal, Debabrata; Sukul, Dipankar; Bhattacharyya, Kankan

    1999-10-01

    The photophysical process of the laser dye 4-(dicyanomethylene)-2-methyl-6-( p-dimethylaminostyryl)-4H-pyran (DCM) is studied in aerosol-OT (AOT) microemulsions in n-heptane using picosecond spectroscopy. When AOT and water are added to a solution of DCM in n-heptane, some of the DCM molecules migrate from bulk n-heptane to the water pool. The absorption and emission peaks of the DCM molecules in the polar water pool are markedly red shifted from those in the bulk n-heptane and the emission intensity in the water pool is nearly 40 times higher. Dual emission is not observed in the microemulsions. DCM exhibits slow solvation dynamics in the water pool with an average solvation time of 1.23 ns.

  19. Common variation at 6p21.31 (BAK1) influences the risk of chronic lymphocytic leukemia

    PubMed Central

    Di Bernardo, Maria Chiara; Conde, Lucia; Broderick, Peter; McDonnell, Shannon K.; Goldin, Lynn R.; Croft, Naomi; Holroyd, Amy; Harris, Shelley; Riby, Jacques; Serie, Daniel J.; Kay, Neil E.; Call, Timothy G.; Bracci, Paige M.; Halperin, Eran; Lanasa, Mark C.; Cunningham, Julie M.; Leis, Jose F.; Morrison, Vicki A.; Spector, Logan G.; Vachon, Celine M.; Shanafelt, Tait D.; Strom, Sara S.; Camp, Nicola J.; Weinberg, J. Brice; Matutes, Estella; Caporaso, Neil E.; Wade, Rachel; Dyer, Martin J. S.; Dearden, Claire; Cerhan, James R.; Catovsky, Daniel

    2012-01-01

    We performed a meta-analysis of 3 genome-wide association studies to identify additional common variants influencing chronic lymphocytic leukemia (CLL) risk. The discovery phase was composed of genome-wide association study data from 1121 cases and 3745 controls. Replication analysis was performed in 861 cases and 2033 controls. We identified a novel CLL risk locus at 6p21.33 (rs210142; intronic to the BAK1 gene, BCL2 antagonist killer 1; P = 9.47 × 10−16). A strong relationship between risk genotype and reduced BAK1 expression was shown in lymphoblastoid cell lines. This finding provides additional support for polygenic inheritance to CLL and provides further insight into the biologic basis of disease development. PMID:22700719

  20. Evaluation of GWAS-identified SNPs at 6p22 with neuroblastoma susceptibility in a Chinese population.

    PubMed

    He, Jing; Zhang, Ruizhong; Zou, Yan; Zhu, Jinhong; Yang, Tianyou; Wang, Fenghua; Xia, Huimin

    2016-02-01

    Previous genome-wide association studies (GWASs) have reported that three single nucleotide polymorphisms (SNPs) (rs6939340 A>G, rs4712653 T>C, and rs9295536 C>A) located at 6p22 locus were associated with neuroblastoma susceptibility for Caucasian descent. We conducted this hospital-based case-control study with 201 neuroblastoma patients and 531 controls to investigate the association between these three SNPs in the FLJ22536 gene with neuroblastoma susceptibility in the Chinese Han population. The odds ratio (OR) and 95 % confidence interval (CI) were calculated to estimate the strength of the association using unconditional logistic regression model. We found that the rs6939340 A allele carriers were associated with significantly decreased neuroblastoma susceptibility (AG vs. GG: adjusted OR = 0.54, 95 % CI = 0.38-0.77; AA vs. GG: adjusted OR = 0.49, 95 % CI = 0.25-0.93; and AA/AG vs. GG: adjusted OR = 0.53, 95 % CI = 0.38-0.74) after adjustment for age and gender. The protective association between variant allele and neuroblastoma susceptibility was also observed for the rs4712653 and rs9295536 polymorphisms. Moreover, we found that subjects carrying one or more protective genotypes had a much lower neuroblastoma susceptibility than non-carriers (adjusted OR = 0.60, 95 % CI = 0.43-0.83). Our study verified that the associations between all of the three SNPs in the 6p22 locus are associated with neuroblastoma susceptibility in the Chinese subjects. Further prospective multicenter studies with different ethnicities and larger sample size are needed to validate our findings.

  1. Positioning atypical protein kinase C isoforms in the UV-induced apoptotic signaling cascade.

    PubMed Central

    Berra, E; Municio, M M; Sanz, L; Frutos, S; Diaz-Meco, M T; Moscat, J

    1997-01-01

    Recent studies have documented the involvement of the atypical protein kinase C (aPKC) isoforms in important cellular functions such as cell proliferation and survival. Exposure of cells to a genotoxic stimulus that induces apoptosis, such as UV irradiation, leads to a profound inhibition of the atypical PKC activity in vivo. In this study, we addressed the relationship between this phenomenon and different proteins involved in the apoptotic response. We show that (i) the inhibition of the aPKC activity precedes UV-induced apoptosis; (ii) UV-induced aPKC inhibition and apoptosis are independent of p53; (iii) Bcl-2 proteins are potent modulators of aPKC activity; and (iv) the aPKCs are located upstream of the interleukin-converting enzyme-like protease system, which is required for the induction of apoptosis by both Par-4 (a selective aPKC inhibitor) and UV irradiation. We also demonstrate here that inhibition of aPKC activity leads to a decrease in mitogen-activated protein (MAP) kinase activity and simultaneously an increase in p38 activity. Both effects are critical for the induction of apoptosis in response to Par-4 expression and UV irradiation. Collectively, these results clarify the position of the aPKCs in the UV-induced apoptotic pathway and strongly suggest that MAP kinases play a role in this signaling cascade. PMID:9234692

  2. Expression of VEGF(xxx)b, the inhibitory isoforms of VEGF, in malignant melanoma.

    PubMed

    Pritchard-Jones, R O; Dunn, D B A; Qiu, Y; Varey, A H R; Orlando, A; Rigby, H; Harper, S J; Bates, D O

    2007-07-16

    Malignant melanoma is the most lethal of the skin cancers and the UK incidence is rising faster than that of any other cancer. Angiogenesis - the growth of new vessels from preexisting vasculature - is an absolute requirement for tumour survival and progression beyond a few hundred microns in diameter. We previously described a class of anti-angiogenic isoforms of VEGF, VEGF(xxx)b, that inhibit tumour growth in animal models, and are downregulated in some cancers, but have not been investigated in melanoma. To determine whether VEGF(xxx)b expression was altered in melanoma, PCR and immunohistochemistry of archived human tumour samples were used. In normal epidermis and in a proportion of melanoma samples, VEGF(xxx)b staining was seen. Some melanomas had much weaker staining. Subsequent examination revealed that expression was significantly reduced in primary melanoma samples (both horizontal and vertical growth phases) from patients who subsequently developed tumour metastasis compared with those who did not (analysis of variance (ANOVA) P<0.001 metastatic vs nonmetastatic), irrespective of tumour thickness, while the surrounding epidermis showed no difference in expression. Staining for total VEGF expression showed staining in metastatic and nonmetastatic melanomas, and normal epidermis. An absence of VEGF(xxx)b expression appears to predict metastatic spread in patients with primary melanoma. These results suggest that there is a switch in splicing as part of the metastatic process, from anti-angiogenic to pro-angiogenic VEGF isoforms. This may form part of a wider metastatic splicing phenotype.

  3. An alternatively spliced IL-15 isoform modulates abrasion-induced keratinocyte activation.

    PubMed

    Lee, Tsung-Lin; Chang, Mei-Ling; Lin, Yu-Jei; Tsai, Ming-Hsun; Chang, Yi-Hsuan; Chuang, Che-Ming; Chien, Yun; Sosinowski, Tomasz; Wang, Chih-Hsiu; Chen, Yi-Yuan; Lee, Chien-Kuo; Chen, Jau-Shiuh; Wang, Li-Fang; Kung, John T; Ku, Chia-Chi

    2015-05-01

    In a routine phenotype-driven screen, we identified a point mutation in exon 7 of the IL-15 gene in Pedigree 191 (deficient memory (DM)) of N-ethyl-N-nitrosourea mutagenized mice. The DM epidermis expressed an alternatively spliced IL-15 mRNA isoform, IL-15ΔE7, and a wild-type (WT) IL-15 isoform at comparable levels. Mechanical stimulation of DM skin or DM skin graft transplanted onto the WT host resulted in reduced keratinocyte activation and inhibition of neutrophil infiltration into the dermis, demonstrating that DM keratinocytes produced less inflammatory response to external stimulation. Ectopic expression of IL-15ΔE7 in WT skin prevented abrasion-induced epidermal thickening, blocked the accumulation of nuclear antigen Ki67(+) cells in the basal and the suprabasal cell layers, increased loricrin expression, and also increased keratinocyte CXCL1 and G-CSF production. IL-15ΔE7 also profoundly blocked neutrophil infiltration in SDS- or immiquimod (IMQ)-treated WT skin. Recombinant IL-15ΔE7 failed to activate STAT-5 and its downstream target bcl-2 expression. Our study points to IL-15ΔE7 as a potential therapeutic agent for treating neutrophilia-associated inflammatory skin disorders.

  4. The pivotal role of PDGF and its receptor isoforms in adipose-derived stem cells.

    PubMed

    Kim, Won-Serk; Park, Hyung-Sook; Sung, Jong-Hyuk

    2015-07-01

    Platelet-derived growth factor (PDGF) is one of the growth factors that reportedly regulates cell growth and division of mesenchymal cells. Although PDGF isoforms and their receptors reportedly play a pivotal role in mesenchymal stem cell regulation, there is a paucity of literature reviewing the role of PDGF in adipose-derived stem cells (ASCs). Therefore, we summarized previous reports on the expression and functional roles of PDGF and its receptor isoforms in this review. In addition, we examined findings pertaining to underlying molecular mechanisms and signaling pathways with special focus on PDGF-D/PDGFRβ. ASCs only express PDGF-A, -C, -D, PDGFRα, and PDGFRβ. PDGFRα expression decreases with adipocyte lineage, while PDGFRβ inhibits white adipocyte differentiation. In addition, PDGFRβ induces proliferation, migration, and angiogenesis and up-regulates the expression of paracrine factors in ASCs. Although PDGF-B and -D mediate their functions mainly by PDGFRβ and ROS generation, there are many differences between them in terms of regulating ASCs. PDGF-D is endogenous, generates ROS via the mitochondrial electron transport system, and regulates the autocrine loop of ASCs in vivo. Furthermore, PDGF-D has stronger mitogenic effects than PDGF-B.

  5. Differential regulation of amyloid-β endocytic trafficking and lysosomal degradation by apolipoprotein E isoforms.

    PubMed

    Li, Jie; Kanekiyo, Takahisa; Shinohara, Mitsuru; Zhang, Yunwu; LaDu, Mary Jo; Xu, Huaxi; Bu, Guojun

    2012-12-28

    Aggregation of amyloid-β (Aβ) peptides leads to synaptic disruption and neurodegeneration in Alzheimer disease (AD). A major Aβ clearance pathway in the brain is cellular uptake and degradation. However, how Aβ traffics through the endocytic pathway and how AD risk factors regulate this event is unclear. Here we show that the majority of endocytosed Aβ in neurons traffics through early and late endosomes to the lysosomes for degradation. Overexpression of Rab5 or Rab7, small GTPases that function in vesicle fusion for early and late endosomes, respectively, significantly accelerates Aβ endocytic trafficking to the lysosomes. We also found that a portion of endocytosed Aβ traffics through Rab11-positive recycling vesicles. A blockage of this Aβ recycling pathway with a constitutively active Rab11 mutant significantly accelerates cellular Aβ accumulation. Inhibition of lysosomal enzymes results in Aβ accumulation and aggregation. Importantly, apolipoprotein E (apoE) accelerates neuronal Aβ uptake, lysosomal trafficking, and degradation in an isoform-dependent manner with apoE3 more efficiently facilitating Aβ trafficking and degradation than apoE4, a risk factor for AD. Taken together, our results demonstrate that Aβ endocytic trafficking to lysosomes for degradation is a major Aβ clearance pathway that is differentially regulated by apoE isoforms. A disturbance of this pathway can lead to accumulation and aggregation of cellular Aβ capable of causing neurotoxicity and seeding amyloid.

  6. Isoform-selective disruption of AKAP-localized PKA using hydrocarbon stapled peptides.

    PubMed

    Wang, Yuxiao; Ho, Tienhuei G; Bertinetti, Daniela; Neddermann, Matthias; Franz, Eugen; Mo, Gary C H; Schendowich, Lewis P; Sukhu, Avinash; Spelts, Raybun C; Zhang, Jin; Herberg, Friedrich W; Kennedy, Eileen J

    2014-03-21

    A-kinase anchoring proteins (AKAPs) play an important role in the spatial and temporal regulation of protein kinase A (PKA) by scaffolding critical intracellular signaling complexes. Here we report the design of conformationally constrained peptides that disrupt interactions between PKA and AKAPs in an isoform-selective manner. Peptides derived from the A Kinase Binding (AKB) domain of several AKAPs were chemically modified to contain an all-hydrocarbon staple and target the docking/dimerization domain of PKA-R, thereby occluding AKAP interactions. The peptides are cell-permeable against diverse human cell lines, are highly isoform-selective for PKA-RII, and can effectively inhibit interactions between AKAPs and PKA-RII in intact cells. These peptides can be applied as useful reagents in cell-based studies to selectively disrupt AKAP-localized PKA-RII activity and block AKAP signaling complexes. In summary, the novel hydrocarbon-stapled peptides developed in this study represent a new class of AKAP disruptors to study compartmentalized RII-regulated PKA signaling in cells.

  7. Design and synthesis of benzodiazepine analogs as isoform-selective human lysine deacetylase inhibitors.

    PubMed

    Reddy, D Rajasekhar; Ballante, Flavio; Zhou, Nancy J; Marshall, Garland R

    2017-02-15

    A comprehensive investigation was performed to identify new benzodiazepine (BZD) derivatives as potent and selective human lysine deacetylase inhibitors (hKDACis). A total of 108 BZD compounds were designed, synthesized and from that 104 compounds were biologically evaluated against human lysine deacetylases (hKDACs) 1, 3 and 8 (class I) and 6 (class IIb). The most active compounds showed mid-nanomolar potencies against hKDACs 1, 3 and 6 and micromolar activity against hKDAC8, while a promising compound (6q) showed selectivity towards hKDAC3 among the different enzyme isoforms. An hKDAC6 homology model, refined by molecular dynamics simulation was generated, and molecular docking studies performed to rationalize the dominant ligand-residue interactions as well as to define structure-activity-relationships. Experimental results confirmed the usefulness of the benzodiazepine moiety as capping group when pursuing hKDAC isoform-selectivity inhibition, suggesting its continued use when designing new hKDACis.

  8. De-novo 'pure' partial trisomy (6)(p22.3→pter): a case report and review of the literature.

    PubMed

    Sivasankaran, Aswini; Murthy, Kanakavalli; Oruganti, Venkata P; Deenadayalu, Anuradha; R Samuel, Chandra; Kandukuri, Lakshmi R

    2017-01-01

    Partial trisomy of the short arm of chromosome 6 is a rare and clinically distinct syndrome. The breakpoints have been found to be variable ranging from bands 6p11 to 6p25. This study reports partial trisomy for 6p22.3→pter in a 2-year-old boy referred with a complaint of developmental delay and facial dysmorphism. Conventional cytogenetic analysis showed the presence of an abnormal chromosome 5 resulting from an unbalanced translocation in the proband. Array comparative genomic hybridization revealed trisomy of distal 6p which was confirmed by fluorescence in situ hybridization using subtelomeric probes for chromosomes 5 and 6. A comparison of the phenotypic features in similar cases of trisomy for different segments of 6p will facilitate an accurate karyotype-phenotype correlation and, subsequently, in the identification of the candidate genes through molecular characterization of the potential genes mapped to these loci.

  9. Isoliquiritigenin showed strong inhibitory effects towards multiple UDP-glucuronosyltransferase (UGT) isoform-catalyzed 4-methylumbelliferone (4-MU) glucuronidation.

    PubMed

    Lu, Hang; Fang, Zhong-Ze; Cao, Yun-Feng; Hu, Cui-Min; Hong, Mo; Sun, Xiao-Yu; Li, Hua; Liu, Yan; Fu, Xiaoguang; Sun, Hongzhi

    2013-01-01

    Isoliquiritigenin, a herbal ingredient with chalcone structure, has been speculated to be able to inhibit one of the most drug-metabolizing enzymes (DMEs) UDP-glucuronosyltransferase (UGT). Therefore, the aim of the present study was to investigate the inhibition of isoliquiritigenin towards important UGT isoforms in the liver and intestine, including UGT1A1, 1A3, 1A6, 1A7, 1A8, 1A9 and 1A10. The recombinant UGT-catalyzed 4-methylumbelliferone (4-MU) glucuronidation was used as probe reactions. The results showed that 100μM of isoliquiritigenin inhibited the activity of UGT1A1, UGT1A3, UGT1A6, UGT1A7, UGT1A8, UGT1A9, and UGT1A10 by 95.2%, 76.1%, 78.9%, 87.2%, 67.2%, 94.8%, and 91.7%, respectively. The data fitting using Dixon plot and Lineweaver-Burk plot showed that the inhibition of UGT1A1, UGT1A9 and UGT1A10 by isoliquiritigenin was all best fit to the competitive inhibition, and the second plot using the slopes from the Lineweaver-Burk plot versus isoliquiritigenin concentrations was used to calculate the inhibition kinetic parameter (K(i)) to be 0.7μM, 0.3μM, and 18.3μM for UGT1A1, UGT1A9, and UGT1A10, respectively. All these results indicated the risk of clinical application of isoliquiritigenin on the drug-drug interaction and other possible diseases induced by the inhibition of isoliquiritigenin towards these UGT isoforms.

  10. Murine Sirt3 protein isoforms have variable half-lives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sirt3 is a NAD+-dependent protein deacetylase mainly localized in mitochondria. Recent studies indicate that the murine Sirt3 gene expresses different transcript variants resulting in three possible Sirt3 protein isoforms with variable lengths at the N-terminus: M1 (aa 1-334), M2 (aa 15-334), and M3...

  11. Actin and myosin isoforms in aneural and malformed chick hearts.

    PubMed

    Kirby, M L; Shimizu, N; Gagnon, J; Toyofuku, T; Kennedy, J; Conrad, D C; Zak, R

    1990-09-01

    Although it is generally accepted that actin and myosin isoforms adapt to their functional requirements, the sequence of expression of these proteins in hearts developing abnormally is unknown. In the chick embryo it is possible to change various aspects of heart development without direct manipulation of the cardiovascular system, by removing various regions of the neural crest from early embryos. The neural crest provides both neural (sympathetic and parasympathetic) and ectomesenchymal components to the heart, and selective removal of various areas results in embryos with sympathetically aneural hearts, or persistent truncus arteriosus with or without parasympathetic denervation. Myosin isoform expression was studied in each of these types of hearts using an array of myosin antibodies specific for atrium, ventricle or the conduction system. Myosin expression in experimental hearts was found to follow the normal pattern of development using these antibodies. Actin expression was studied using cDNA probes for the 3' untranslated region of actin mRNA of the alpha-skeletal, alpha-cardiac and beta-actin isoforms. Using slot-blot hybridization analysis, the pattern of actin expression in atrium and ventricle was followed throughout the period of incubation in normal hearts. The pattern of actin expression was found to be abnormal in hearts which were sympathetically aneural and those which had persistent truncus arteriosus combined with parasympathetic denervation. ATPase activity was increased only in atria of hearts with persistent truncus arteriosus. It appears from these experiments that actin isoform expression is influenced in the chick heart by autonomic innervation.

  12. Bacteria-Induced Dscam Isoforms of the Crustacean, Pacifastacus leniusculus.

    PubMed

    Watthanasurorot, Apiruck; Jiravanichpaisal, Pikul; Liu, Haipeng; Söderhäll, Irene; Söderhäll, Kenneth

    2011-06-01

    The Down syndrome cell adhesion molecule, also known as Dscam, is a member of the immunoglobulin super family. Dscam plays an essential function in neuronal wiring and appears to be involved in innate immune reactions in insects. The deduced amino acid sequence of Dscam in the crustacean Pacifastacus leniusculus (PlDscam), encodes 9(Ig)-4(FNIII)-(Ig)-2(FNIII)-TM and it has variable regions in the N-terminal half of Ig2 and Ig3 and the complete Ig7 and in the transmembrane domain. The cytoplasmic tail can generate multiple isoforms. PlDscam can generate more than 22,000 different unique isoforms. Bacteria and LPS injection enhanced the expression of PlDscam, but no response in expression occurred after a white spot syndrome virus (WSSV) infection or injection with peptidoglycans. Furthermore, PlDscam silencing did not have any effect on the replication of the WSSV. Bacterial specific isoforms of PlDscam were shown to have a specific binding property to each tested bacteria, E. coli or S. aureus. The bacteria specific isoforms of PlDscam were shown to be associated with bacterial clearance and phagocytosis in crayfish.

  13. Role of p53 isoforms and aggregations in cancer

    PubMed Central

    Kim, SeJin; An, Seong Soo A.

    2016-01-01

    Abstract p53 is a master regulatory protein that is involved in diverse cellular metabolic processes such as apoptosis, DNA repair, and cell cycle arrest. The protective function of p53 (in its homotetrameric form) as a tumor suppressor is lost in more than 50% of human cancers. Despite considerable experimental evidence suggesting the presence of multiple p53 states, it has been difficult to correlate the status of p53 with cancer response to treatments and clinical outcomes, which suggest the importance of complex but essential p53 regulatory pathways. Recent studies have indicated that the expression pattern of p53 isoforms may play a crucial role in regulating normal and cancer cell fates in response to diverse stresses. The human TP53 gene encodes at least 12 p53 isoforms, which are produced in normal tissue through alternative initiation of translation, usage of alternative promoters, and alternative splicing. Furthermore, some researchers have suggested that the formation of mutant p53 aggregates may be associated with cancer pathogenesis due to loss-of function (LoF), dominant-negative (DN), and gain-of function (GoF) effects. As different isoforms or the aggregation state of p53 may influence tumorigenesis, this review aims to examine the correlation of p53 isoforms and aggregation with cancer. PMID:27368003

  14. APPRIS: annotation of principal and alternative splice isoforms.

    PubMed

    Rodriguez, Jose Manuel; Maietta, Paolo; Ezkurdia, Iakes; Pietrelli, Alessandro; Wesselink, Jan-Jaap; Lopez, Gonzalo; Valencia, Alfonso; Tress, Michael L

    2013-01-01

    Here, we present APPRIS (http://appris.bioinfo.cnio.es), a database that houses annotations of human splice isoforms. APPRIS has been designed to provide value to manual annotations of the human genome by adding reliable protein structural and functional data and information from cross-species conservation. The visual representation of the annotations provided by APPRIS for each gene allows annotators and researchers alike to easily identify functional changes brought about by splicing events. In addition to collecting, integrating and analyzing reliable predictions of the effect of splicing events, APPRIS also selects a single reference sequence for each gene, here termed the principal isoform, based on the annotations of structure, function and conservation for each transcript. APPRIS identifies a principal isoform for 85% of the protein-coding genes in the GENCODE 7 release for ENSEMBL. Analysis of the APPRIS data shows that at least 70% of the alternative (non-principal) variants would lose important functional or structural information relative to the principal isoform.

  15. ROCK in CNS: Different Roles of Isoforms and Therapeutic Target for Neurodegenerative Disorders.

    PubMed

    Chong, Cheong-Meng; Ai, Nana; Lee, Simon Ming-Yuen

    2017-01-01

    Rho-associated protein kinase (ROCK) is a serine-threonine kinase originally identified as a crucial regulator of actin cytoskeleton. Recent studies have defined new functions of ROCK as a critical component of diverse signaling pathways in neurons. In addition, inhibition of ROCK causes several biological events such as increase of neurite outgrowth, axonal regeneration, and activation of prosurvival Akt. Thus, it has attracted scientist's strong attentions and considered ROCK as a promising therapeutic target for the treatment of neurodegenerative disorders including Alzheimer disease, Parkinson's disease, Huntington';s disease, multiple sclerosis, and amyotrophic lateral sclerosis. However, ROCK has two highly homologous isoforms, ROCK1 and ROCK2. Accumulated evidences indicate that ROCK1 and ROCK2 might involve in distinct cellular functions in central nervous system (CNS) and neurodegenerative processes. This review summarizes recent updates regarding ROCK isoformspecific functions in CNS and the progress of ROCK inhibitors in preclinical studies for neurodegenerative diseases.

  16. Functional characterization of a BCL10 isoform in the rainbow trout Oncorhynchus mykiss

    PubMed Central

    Mazzone, Pellegrino; Scudiero, Ivan; Coccia, Elena; Ferravante, Angela; Paolucci, Marina; D’Andrea, Egildo Luca; Varricchio, Ettore; Pizzulo, Maddalena; Reale, Carla; Zotti, Tiziana; Vito, Pasquale; Stilo, Romania

    2015-01-01

    The complexes formed by BCL10, MALT1 and members of the family of CARMA proteins have recently been the focus of much attention because they represent a key mechanism for regulating activation of the transcription factor NF-κB. Here, we report the functional characterization of a novel isoform of BCL10 in the trout Oncorhynchus mykiss, which we named tBCL10. tBCL10 dimerizes, binds to components of the CBM complex and forms cytoplasmic filaments. Functionally, tBCL10 activates NF-κB transcription factor and is inhibited by the deubiquitinating enzyme A20. Finally, depletion experiments indicate that tBCL10 can functionally replace the human protein. This work demonstrates the evolutionary conservation of the mechanism of NF-κB activation through the CBM complex, and indicates that the rainbow trout O.mykiss can serve as a model organism to study this pathway. PMID:25834783

  17. Functional characterization of a BCL10 isoform in the rainbow trout Oncorhynchus mykiss.

    PubMed

    Mazzone, Pellegrino; Scudiero, Ivan; Coccia, Elena; Ferravante, Angela; Paolucci, Marina; D'Andrea, Egildo Luca; Varricchio, Ettore; Pizzulo, Maddalena; Reale, Carla; Zotti, Tiziana; Vito, Pasquale; Stilo, Romania

    2015-01-01

    The complexes formed by BCL10, MALT1 and members of the family of CARMA proteins have recently been the focus of much attention because they represent a key mechanism for regulating activation of the transcription factor NF-κB. Here, we report the functional characterization of a novel isoform of BCL10 in the trout Oncorhynchus mykiss, which we named tBCL10. tBCL10 dimerizes, binds to components of the CBM complex and forms cytoplasmic filaments. Functionally, tBCL10 activates NF-κB transcription factor and is inhibited by the deubiquitinating enzyme A20. Finally, depletion experiments indicate that tBCL10 can functionally replace the human protein. This work demonstrates the evolutionary conservation of the mechanism of NF-κB activation through the CBM complex, and indicates that the rainbow trout O . mykiss can serve as a model organism to study this pathway.

  18. Diclofenac, a nonsteroidal anti-inflammatory drug, is an antagonist of human TRPM3 isoforms.

    PubMed

    Suzuki, Hiroka; Sasaki, Eiji; Nakagawa, Ayumi; Muraki, Yukiko; Hatano, Noriyuki; Muraki, Katsuhiko

    2016-06-01

    The effects of diclofenac (Dic), an acetic acid derivative-type nonsteroidal anti-inflammatory drug, were examined on the function of transient receptor potential (TRP) melastatin (TRPM) 3 (TRPM3) in human embryonic kidney 293 cell-line (HEK293) cells with recombinant human TRPM3 isoforms (TRPM31325, TRPM3-3, TRPM3-9, and TRPM3-S) and in a neuroblastoma cell line human neuroblastoma IMR-32 cells (IMR-32 cells) derived from human peripheral neurons. TRPM3 responses evoked by pregnenolone sulfate (PregS) were effectively inhibited by Dic in a concentration-dependent manner in Ca(2+) measurement and electrophysiological assays. The apparent IC 50 for PregS-induced Ca(2+) response of TRPM31325, TRPM3-3, and TRPM3-9 was calculated to be 18.8, 42.5, and 7.1 μmol/L, respectively. The TRPM3-dependent Ca(2+) responses evoked by nifedipine, another TRPM3 agonist, were also significantly inhibited by Dic. In contrast, aceclofenac, an acetoxymethyl analog of Dic, had no effects on PregS-induced TRPM3 responses. Constitutive channel activity of TRPM3-S without TRPM3 agonists was substantially inhibited by Dic, ruling out the possibility of interaction of Dic against TRPM3 agonists to the channel binding sites. Moreover, Dic reversibly inhibited TRPM3 single-channel activity recorded in excised outside-out patches without affecting the channel conductance. In differentiated neuronal IMR-32 cells with endogenous TRPM3, Dic inhibited PregS-evoked Ca(2+) responses with an apparent IC 50 of 17.1 μmol/L. Taken together, our findings demonstrate that Dic inhibits human TRPM3 without interacting with the channel pore.

  19. Mast cells express novel functional IL-15 receptor alpha isoforms.

    PubMed

    Bulanova, Elena; Budagian, Vadim; Orinska, Zane; Krause, Hans; Paus, Ralf; Bulfone-Paus, Silvia

    2003-05-15

    Mast cells previously have been reported to be regulated by IL-15 and to express a distinct IL-15R, termed IL-15RX. To further examine IL-15 binding and signaling in mast cells, we have studied the nature of the IL-15R and some of its biological activities in these cells. In this study, we report the existence of three novel isoforms of the IL-15R alpha chain in murine bone marrow-derived mast cells as a result of an alternative exon-splicing mechanism within the IL-15R alpha gene. These correspond to new mRNA transcripts lacking exon 4; exons 3 and 4; or exons 3, 4, and 5 (IL-15R alpha Delta 4, IL-15R alpha Delta 3,4, IL-15R alpha Delta 3,4,5). After transient transfection in COS-7 cells, all IL-15R alpha isoforms associate with the Golgi apparatus, the endoplasmic reticulum, the perinuclear space, and the cell membrane. Analysis of glycosylation pattern demonstrates the usage of a single N-glycosylation site, while no O-glycosylation is observed. Importantly, IL-15 binds with high affinity to, and promotes the survival of, murine BA/F3 cells stably transfected with the IL-15R alpha isoforms. Furthermore, we report that signaling mediated by IL-15 binding to the newly identified IL-15R alpha isoforms involves the phosphorylation of STAT3, STAT5, STAT6, Janus kinase 2, and Syk kinase. Taken together, our data indicate that murine mast cells express novel, fully functional IL-15R alpha isoforms, which can explain the selective regulatory effects of IL-15 on these cells.

  20. Distinct Metal Isoforms Underlie Promiscuous Activity Profiles of Metalloenzymes.

    PubMed

    Baier, Florian; Chen, John; Solomonson, Matthew; Strynadka, Natalie C J; Tokuriki, Nobuhiko

    2015-07-17

    Within a superfamily, functionally diverged metalloenzymes often favor different metals as cofactors for catalysis. One hypothesis is that incorporation of alternative metals expands the catalytic repertoire of metalloenzymes and provides evolutionary springboards toward new catalytic functions. However, there is little experimental evidence that incorporation of alternative metals changes the activity profile of metalloenzymes. Here, we systematically investigate how metals alter the activity profiles of five functionally diverged enzymes of the metallo-β-lactamase (MBL) superfamily. Each enzyme was reconstituted in vitro with six different metals, Cd(2+), Co(2+), Fe(2+), Mn(2+), Ni(2+), and Zn(2+), and assayed against eight catalytically distinct hydrolytic reactions (representing native functions of MBL enzymes). We reveal that each enzyme metal isoform has a significantly different activity level for native and promiscuous reactions. Moreover, metal preferences for native versus promiscuous activities are not correlated and, in some cases, are mutually exclusive; only particular metal isoforms disclose cryptic promiscuous activities but often at the expense of the native activity. For example, the L1 B3 β-lactamase displays a 1000-fold catalytic preference for Zn(2+) over Ni(2+) for its native activity but exhibits promiscuous thioester, phosphodiester, phosphotriester, and lactonase activity only with Ni(2+). Furthermore, we find that the five MBL enzymes exist as an ensemble of various metal isoforms in vivo, and this heterogeneity results in an expanded activity profile compared to a single metal isoform. Our study suggests that promiscuous activities of metalloenzymes can stem from an ensemble of metal isoforms in the cell, which could facilitate the functional divergence of metalloenzymes.

  1. Genome-Wide Mapping of Binding Sites Reveals Multiple Biological Functions of the Transcription Factor Cst6p in Saccharomyces cerevisiae

    PubMed Central

    Bergenholm, David

    2016-01-01

    ABSTRACT In the model eukaryote Saccharomyces cerevisiae, the transcription factor Cst6p has been reported to play important roles in several biological processes. However, the genome-wide targets of Cst6p and its physiological functions remain unknown. Here, we mapped the genome-wide binding sites of Cst6p at high resolution. Cst6p binds to the promoter regions of 59 genes with various biological functions when cells are grown on ethanol but hardly binds to the promoter at any gene when cells are grown on glucose. The retarded growth of the CST6 deletion mutant on ethanol is attributed to the markedly decreased expression of NCE103, encoding a carbonic anhydrase, which is a direct target of Cst6p. The target genes of Cst6p have a large overlap with those of stress-responsive transcription factors, such as Sko1p and Skn7p. In addition, a CST6 deletion mutant growing on ethanol shows hypersensitivity to oxidative stress and ethanol stress, assigning Cst6p as a new member of the stress-responsive transcriptional regulatory network. These results show that mapping of genome-wide binding sites can provide new insights into the function of transcription factors and highlight the highly connected and condition-dependent nature of the transcriptional regulatory network in S. cerevisiae. PMID:27143390

  2. Inhibitory properties of trapping agents: glutathione, potassium cyanide, and methoxylamine, against major human cytochrome p450 isoforms.

    PubMed

    Zhang, Chenghong; Wong, Susan; Delarosa, Erlie M; Kenny, Jane R; Halladay, Jason S; Hop, Cornelis E; Khojasteh-Bakht, Siamak Cyrus

    2009-04-01

    In the early stages of drug discovery, the formation of reactive metabolites is often assessed by co-incubating the drug in liver microsomes with a trapping agent in the presence of NADPH. Our group assessed the capability of commonly used trapping agents to reversibly inhibit major cytochrome P450 (CYP) isoforms. Glutathione and cyanide did not inhibit the enzymes at concentrations up to 10 mM; however methoxylamine did show inhibition, with IC(50) values of 0.53 mM for CYP1A2, 4.12 mM for CYP2C9, 2.04 mM for CYP2C19, 9.72 mM for CYP2D6, and 1.26 and >10 mM for CYP3A4/5 (for testosterone and midazolam, respectively, as substrates).

  3. The p53 isoform delta133p53ß regulates cancer cell apoptosis in a RhoB-dependent manner

    PubMed Central

    Arsic, Nikola; Ho-Pun-Cheung, Alexandre; Evelyne, Crapez; Assenat, Eric; Jarlier, Marta; Anguille, Christelle; Colard, Manon; Pezet, Mikaël

    2017-01-01

    The TP53 gene plays essential roles in cancer. Conventionally, wild type (WT) p53 is thought to prevent cancer development and metastasis formation, while mutant p53 has transforming abilities. However, clinical studies failed to establish p53 mutation status as an unequivocal predictive or prognostic factor of cancer progression. The recent discovery of p53 isoforms that can differentially regulate cell cycle arrest and apoptosis suggests that their expression, rather than p53 mutations, could be a more clinically relevant biomarker in patients with cancer. In this study, we show that the p53 isoform delta133p53ß is involved in regulating the apoptotic response in colorectal cancer cell lines. We first demonstrate delta133p53ß association with the small GTPase RhoB, a well-described anti-apoptotic protein. We then show that, by inhibiting RhoB activity, delta133p53ß protects cells from camptothecin-induced apoptosis. Moreover, we found that high delta133p53 mRNA expression levels are correlated with higher risk of recurrence in a series of patients with locally advanced rectal cancer (n = 36). Our findings describe how a WT TP53 isoform can act as an oncogene and add a new layer to the already complex p53 signaling network. PMID:28212429

  4. Dephosphorylation of human cyclin-dependent kinases by protein phosphatase type 2C alpha and beta 2 isoforms.

    PubMed

    Cheng, A; Kaldis, P; Solomon, M J

    2000-11-03

    We previously reported that the activating phosphorylation on cyclin-dependent kinases in yeast (Cdc28p) and in humans (Cdk2) is removed by type 2C protein phosphatases. In this study, we characterize this PP2C-like activity in HeLa cell extract and determine that it is due to PP2C beta 2, a novel PP2C beta isoform, and to PP2C alpha. PP2C alpha and PP2C beta 2 co-purified with Mg(2+)-dependent Cdk2/Cdk6 phosphatase activity in DEAE-Sepharose, Superdex-200, and Mono Q chromatographies. Moreover, purified recombinant PP2C alpha and PP2C beta 2 proteins efficiently dephosphorylated monomeric Cdk2/Cdk6 in vitro. The dephosphorylation of Cdk2 and Cdk6 by PP2C isoforms was inhibited by the binding of cyclins. We found that the PP2C-like activity in HeLa cell extract, partially purified HeLa PP2C alpha and PP2C beta 2 isoforms, and the recombinant PP2Cs exhibited a comparable substrate preference for a phosphothreonine containing substrate, consistent with the conservation of threonine residues at the site of activating phosphorylation in CDKs.

  5. The isoforms generated by alternative translation initiation adopt similar conformation in the selectivity filter in TREK-2.

    PubMed

    Zhuo, Ren-Gong; Peng, Peng; Liu, Xiao-Yan; Zhang, Shu-Zhuo; Xu, Jiang-Ping; Zheng, Jian-Quan; Wei, Xiao-Li; Ma, Xiao-Yun

    2015-12-01

    TREK-2 (TWIK-related K(+) channel-2), a member of two-pore domain potassium (K2P) channel family, tunes cellular excitability via conducting leak or background currents. In TREK-2, the isoforms generated by alternative translation initiation (ATI) mechanism exhibit large divergence in unitary conductance, but similar in selectivity to K(+). Up to now, the structural basis for this similarity in ion selectivity is unknown. Here, we report that externally applied Ba(2+) inhibits the currents of TREK-2 in a concentration- and time-dependent manner. The blocking effect is blunted by elevated extracellular K(+) or mutation of S4 K(+) binding site, which suggests that the inhibitory mechanism of Ba(2+) is due to its competitive docking properties within the selectivity filter (SF). Next, we demonstrate that all the ATI isoforms exhibit analogous behaviors upon the application of Ba(2+) and alteration of extracellular pH (pHo), which acts on the outer position of the SF. These results strongly support the notion that all the ATI isoforms of TREK-2 possess resembled SF conformation in S4 site and the position defined by pHo, which implicates that neither the role of N-terminus (Nt) nor the unitary conductance is associated with SF conformation. Our findings might help to understand the detail gating mechanism of TREK-2 and K2P channels.

  6. AKT1 and AKT2 isoforms play distinct roles during breast cancer progression through the regulation of specific downstream proteins

    PubMed Central

    Riggio, Marina; Perrone, María C.; Polo, María L.; Rodriguez, María J.; May, María; Abba, Martín; Lanari, Claudia; Novaro, Virginia

    2017-01-01

    The purpose of this study was to elucidate the mechanisms associated with the specific effects of AKT1 and AKT2 isoforms in breast cancer progression. We modulated the abundance of specific AKT isoforms in IBH-6 and T47D human breast cancer cell lines and showed that AKT1 promoted cell proliferation, through S6 and cyclin D1 upregulation, but it inhibited cell migration and invasion through β1-integrin and focal adhesion kinase (FAK) downregulation. In contrast, AKT2 promoted cell migration and invasion through F-actin and vimentin induction. Thus, while overexpression of AKT1 promoted local tumor growth, downregulation of AKT1 or overexpression of AKT2 promoted peritumoral invasion and lung metastasis. Furthermore, we evaluated The Cancer Genome Atlas (TCGA) dataset for invasive breast carcinomas and found that increased AKT2 but not AKT1 mRNA levels correlated with a worse clinical outcome. We conclude that AKT isoforms play specific roles in different steps of breast cancer progression, with AKT1 involved in the local tumor growth and AKT2 involved in the distant tumor dissemination, having AKT2 a poorer prognostic value and consequently being a worthwhile target for therapy. PMID:28287129

  7. Regulation of NKCC2 activity by inhibitory SPAK isoforms: KS-SPAK is a more potent inhibitor than SPAK2

    PubMed Central

    Park, Hae J.; Curry, Joshua N.

    2013-01-01

    The cation cotransporters Na+-K+-2Cl− cotransporter 1 and 2 (NKCC1 and NKCC2) and Na+-Cl cotransporter (NCC) are phosphorylated and activated by the kinases Ste20-related proline alanine-rich kinase (SPAK) and oxidative stress-responsive kinase (OSR1), and their targeted disruption in mice causes phenotypes resembling the human disorders Bartter syndrome and Gitelman syndrome, reflecting reduced NKCC2 and NCC activity, respectively. We previously cloned a kinase-inactive kidney-specific SPAK isoform, kidney-specific (KS)-SPAK, which lacks the majority of the kinase domain present in full-length SPAK. Another putative inactive SPAK isoform, SPAK2, which only lacks the initial portion of the kinase domain, is also highly expressed in kidney. The functional relevance of inactive SPAK isoforms is unclear. Here, we tested whether KS-SPAK and SPAK2 differentially affect cation cotransporter activity. While KS-SPAK and SPAK2 both strongly inhibited NKCC1 activity, SPAK2 was a much weaker inhibitor of NKCC2 activity. Removal of the catalytic loop from SPAK2 resulted in an inhibitory effect on NKCC2 similar to that of KS-SPAK. Full-length SPAK is phosphorylated and activated by members of the with-no-lysine[K] (WNK) kinase family. Mutation of a WNK phosphorylation in KS-SPAK did not alter its ability to inhibit NKCC2 activity. In contrast, we found that residues involved in KS-SPAK interactions with cation cotransporters are required for it to inhibit cotransporter activity. Finally, both KS-SPAK and SPAK2 associated with NKCC2, as demonstrated by coimmunoprecipitation. Together, these data identify the structural basis for the differential effects of KS-SPAK and SPAK2 on cation cotransporter activity that may be physiologically important. PMID:24133122

  8. Regioselective Glucuronidation of Flavonols by Six Human UGT1A Isoforms

    PubMed Central

    Wu, Baojian; Hu, Ming

    2012-01-01

    Purpose Flavonols, a class of polyphenols, show a variety of biological activities such as antioxidant and anticancer. However, rapid in vivo O-glucuronidation posed a challenge to develop them as therapeutic agents. The objective of this paper is to determine the regioselective glucuronidation of flavonols by UGT1A isoforms (i.e., UGT1A1, UGT1A3, UGT1A7, UGT1A8, UGT1A9 and UGT1A10). Methods The kinetics of UGT1A1-, 1A3- and 1A7~1A10-mediated metabolisms of four flavonols that contain 7-OH group were characterized and kinetic parameters (Km, Vmax and intrinsic clearance (CLint=Vmax/Km)) were determined. Results UGT1A1 and 1A3 regioselectively metabolized 7-OH, whereas UGT1A7~1A10 preferred to glucuronidate 3-OH group. UGT1A1 and UGT1A9 were the most efficient conjugating enzymes with Km of ≤1 µM and Vmax/Km of >3 ml/min/mg protein, resulting in a CLint value as high as 6 ml/min/mg protein. Additionally, the four flavonols generally strongly self-inhibited the UGT1A1-mediated glucuronidation, with Ks (substrate inhibition constant) of ≤ 5.4 µM. Conclusion UGT1A isoforms displayed distinct positional preferences between 3-OH and 7-OH in the glucuronidation of flavonols. The differentiated kinetics properties between 3-O- and 7-O- glucuronidation indicated that at least two distinct binding modes within the catalytic domain were responsible for the formation of these two glucuronide isomers. PMID:21472492

  9. Purification, crystallization and preliminary X-ray studies of two isoforms of Rubisco from Alcaligenes eutrophus.

    PubMed

    Hansen, S; Hough, E; Andersen, K

    1999-01-01

    Two different isoforms of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) from Alcaligenes eutrophus have been purified and crystallized. Both isoforms crystallize in space group P43212. Crystals of isoform I (unit-cell dimensions a = 112.0 and c = 402.7 A) diffract to 2.7 A, whereas isoform II (unit-cell dimensions a = 111.8 and c = 400.0 A) presently diffract to 3.2 A, using synchrotron radiation in both cases.

  10. Functional roles of the alpha isoforms of the Na,K-ATPase.

    PubMed

    Lingrel, Jerry; Moseley, Amy; Dostanic, Iva; Cougnon, Marc; He, Suiwen; James, Paul; Woo, Alison; O'Connor, Kyle; Neumann, Jonathan

    2003-04-01

    The Na,K-ATPase is composed of two subunits, alpha and beta, and each subunit consists of multiple isoforms. In the case of alpha, four isoforms, alpha1, alpha2, alpha3, and alpha4 are present in mammalian cells. The distribution of these isoforms is tissue- and developmental-specific, suggesting that they may play specific roles, either during development or coupled to specific physiological processes. In order to understand the functional properties of each of these isoforms, we are using gene targeting, where animals are produced lacking either one copy or both copies of the corresponding gene or have a modified gene. To date, we have produced animals lacking the alpha1 and alpha2 isoform genes. Animals lacking both copies of the alpha1 isoform gene are not viable, while animals lacking both copies of the alpha2 isoform gene make it to birth, but are either born dead or die very soon after. In the case of animals lacking one copy of the alpha1 or alpha2 isoform gene, the animals survive and appear healthy. Heart and EDL muscle from animals lacking one copy of the alpha2 isoform exhibit an increase in force of contraction, while there is reduced force of contraction in both muscles from animals lacking one copy of the alpha1 isoform gene. These studies indicate that the alpha1 and alpha2 isoforms carry out different physiological roles. The alpha2 isoform appears to be involved in regulating Ca(2+) transients involved in muscle contraction, while the alpha1 isoform probably plays a more generalized role. While we have not yet knocked out the alpha3 or alpha4 isoform genes, studies to date indicate that the alpha4 isoform is necessary to maintain sperm motility. It is thus possible that the alpha2, alpha3, and alpha4 isoforms are involved in specialized functions of various tissues, helping to explain their tissue- and developmental-specific regulation.

  11. N Termini of apPDE4 Isoforms Are Responsible for Targeting the Isoforms to Different Cellular Membranes

    ERIC Educational Resources Information Center

    Jang, Deok-Jin; Park, Soo-Won; Lee, Jin-A; Lee, Changhoon; Chae, Yeon-Su; Park, Hyungju; Kim, Min-Jeong; Choi, Sun-Lim; Lee, Nuribalhae; Kim, Hyoung; Kaang, Bong-Kiun

    2010-01-01

    Phosphodiesterases (PDEs) are known to play a key role in the compartmentalization of cAMP signaling; however, the molecular mechanisms underlying intracellular localization of different PDE isoforms are not understood. In this study, we have found that each of the supershort, short, and long forms of apPDE4 showed distinct localization in the…

  12. Rab5 Isoforms Specifically Regulate Different Modes of Endocytosis in Leishmania.

    PubMed

    Rastogi, Ruchir; Verma, Jitender Kumar; Kapoor, Anjali; Langsley, Gordon; Mukhopadhyay, Amitabha

    2016-07-08

    Differential functions of Rab5 isoforms in endocytosis are not well characterized. Here, we cloned, expressed, and characterized Rab5a and Rab5b from Leishmania and found that both of them are localized in the early endosome. To understand the role of LdRab5 isoforms in different modes of endocytosis in Leishmania, we generated transgenic parasites overexpressing LdRab5a, LdRab5b, or their dominant-positive (LdRab5a:Q93L and LdRab5b:Q80L) or dominant-negative mutants (LdRab5a:N146I and LdRab5b:N133I). Using LdRab5a or its mutants overexpressing parasites, we found that LdRab5a specifically regulates the fluid-phase endocytosis of horseradish peroxidase and also specifically induced the transport of dextran-Texas Red to the lysosomes. In contrast, cells overexpressing LdRab5b or its mutants showed that LdRab5b explicitly controls receptor-mediated endocytosis of hemoglobin, and overexpression of LdRab5b:WT enhanced the transport of internalized Hb to the lysosomes in comparison with control cells. To unequivocally demonstrate the role of Rab5 isoforms in endocytosis in Leishmania, we tried to generate null-mutants of LdRab5a and LdRab5b parasites, but both were lethal indicating their essential functions in parasites. Therefore, we used heterozygous LdRab5a(+/-) and LdRab5b(+/-) cells. LdRab5a(+/-) Leishmania showed 50% inhibition of HRP uptake, but hemoglobin endocytosis was uninterrupted. In contrast, about 50% inhibition of Hb endocytosis was observed in LdRab5b(+/-) cells without any significant effect on HRP uptake. Finally, we tried to identify putative LdRab5a and LdRab5b effectors. We found that LdRab5b interacts with clathrin heavy chain and hemoglobin receptor. However, LdRab5a failed to interact with the clathrin heavy chain, and interaction with hemoglobin receptor was significantly less. Thus, our results showed that LdRab5a and LdRab5b differentially regulate fluid phase and receptor-mediated endocytosis in Leishmania.

  13. SPL7013 gel as a topical microbicide for prevention of vaginal transmission of SHIV89.6P in macaques.

    PubMed

    Jiang, Yong-Hou; Emau, Peter; Cairns, J Scott; Flanary, Leon; Morton, William R; McCarthy, Tom D; Tsai, Che-Chung

    2005-03-01

    SPL7013 is a dendrimer with a polyanionic outer surface that allows multiple interactions with target sites. It potently binds and blocks HIV-1 and chimeric simian/HIV-1 viruses (SHIVs) replication in vitro. Gels containing different concentrations of SPL7013 were used as topical microbicides in female pigtailed macaques (Macaca nemestrina) to study their ability to prevent vaginal transmission of SHIV(89,6P). On virus challenge, all untreated macaques (8/8) and seven of eight macaques treated with placebo gel were infected within 2 weeks postinfection (PI) and showed high plasma viremia and dramatic CD4(+) cell decline within 4 weeks PI. In contrast, 6/6 macaques, 5/6 macaques, and 2/6 macaques treated with 5% w/w (50 mg/ml), 3% w/w (30 mg/ml), and 1% w/w (10 mg/ml) SPL7013 gels, respectively, resisted viral challenge. The results showed that animals treated with SPL7013 showed a dose-dependent resistance to virus challenge. Neither SPL7013 nor placebo gels produced any adverse effects following the single application in the study. These results showed that 3-5% w/w SPL7013 gels were effective in blocking vaginal transmission of SHIV in macaques after single gel application followed by single virus challenge. These results suggest that SPL7013 gel may be a promising anti-HIV microbicide formulation for further evaluation.

  14. Bi-Mn mixed metal organic oxide: A novel 3d-6p mixed metal coordination network

    NASA Astrophysics Data System (ADS)

    Shi, Fa-Nian; Rosa Silva, Ana; Bian, Liang

    2015-05-01

    A new terminology of metal organic oxide (MOO) was given a definition as a type of coordination polymers which possess the feature of inorganic connectivity between metals and the direct bonded atoms and show 1D, 2D or 3D inorganic sub-networks. One such compound was shown as an example. A 3d-6p (Mn-Bi. Named MOOMnBi) mixed metals coordination network has been synthesized via hydrothermal method. The new compound with the molecular formula of [MnBi2O(1,3,5-BTC)2]n (1,3,5-BTC stands for benzene-1,3,5-tricarboxylate) was characterized via single crystal X-ray diffraction technique that revealed a very interesting 3-dimensional (3D) framework with Bi4O2(COO)12 clusters which are further connected to Mn(COO)6 fragments into a 2D MOO. The topology study indicates an unprecedented topological type with the net point group of {413.62}{413.68}{416.65}{418.610}{422.614}{43} corresponding to 3,6,7,7,8,9-c hexa-nodal net. MOOMnBi shows catalytic activity in the synthesis of (E)-α,β-unsaturated ketones.

  15. The first detection and whole genome characterization of the G6P[15] group A rotavirus strain from roe deer.

    PubMed

    Jamnikar-Ciglenecki, Urska; Kuhar, Urska; Sturm, Sabina; Kirbis, Andrej; Racki, Nejc; Steyer, Andrej

    2016-08-15

    Although rotaviruses have been detected in a variety of host species, there are only limited records of their occurrence in deer, where their role is unknown. In this study, group A rotavirus was identified in roe deer during a study of enteric viruses in game animals. 102 samples of intestinal content were collected from roe deer (56), wild boars (29), chamois (10), red deer (6) and mouflon (1), but only one sample from roe deer was positive. Following whole genome sequence analysis, the rotavirus strain D38/14 was characterized by next generation sequencing. The genotype constellation, comprising 11 genome segments, was G6-P[15]-I2-R2-C2-M2-A3-N2-T6-E2-H3. Phylogenetic analysis of the VP7 genome segment showed that the D38/14 rotavirus strain is closely related to the various G6 zoonotic rotavirus strains of bovine-like origin frequently detected in humans. In the VP4 segment, this strain showed high variation compared to that in the P[15] strain found in sheep and in a goat. This finding suggests that rotaviruses from deer are similar to those in other DS-1 rotavirus groups and could constitute a source of zoonotically transmitted rotaviruses. The epidemiological status of group A rotaviruses in deer should be further investigated.

  16. Biochemical properties of human pantothenate kinase 2 isoforms and mutations linked to pantothenate kinase-associated neurodegeneration.

    PubMed

    Zhang, Yong-Mei; Rock, Charles O; Jackowski, Suzanne

    2006-01-06

    The PANK2 gene encodes the human pantothenate kinase 2 protein isoforms, and PANK2 mutations are linked to pantothenate kinase-associated neurodegeneration. Two PanK2 protein forms are proteolytically processed to form a mitochondrially localized, mature PanK2. Another isoform arose from a proposed initiation at a leucine codon and was not processed further. The fifth isoform was postulated to arise from an alternative splicing event and was found to encode an inactive protein. Fourteen mutant PanK2 proteins with single amino acid substitutions, associated with either early or late onset disease, were evaluated for activity. The PanK2(G521R), the most frequent mutation in pantothenate kinase-associated neurodegeneration, was devoid of activity and did not fold properly. However, nine of the mutant proteins associated with disease possessed catalytic activities that were indistinguishable from wild type, including the frequently encountered PanK2(T528M) missense mutation. PanK2 was extremely sensitive to feedback inhibition by CoA thioesters (IC50 values between 250 and 500 nM), and the regulation of the active PanK2 mutants was comparable with that of the wild-type protein. Coexpression of the PanK2(G521R) and wild-type PanK2 did not interfere with wild-type enzyme activity, arguing against a dominant negative effect of the PanK2(G521R) mutation in heterozygous patients. These data described the unique biochemical features of the PanK2 isoforms and suggested that catalytic defects may not be the sole cause for the neurodegenerative phenotype.

  17. Attenuation of cardiac contractility in Na,K-ATPase alpha1 isoform-deficient hearts under reduced calcium conditions.

    PubMed

    Moseley, Amy E; Cougnon, Marc H; Grupp, Ingrid L; El Schultz, Jo; Lingrel, Jerry B

    2004-11-01

    We have previously reported that genetic reduction of the Na,K-ATPase alpha1 isoform (alpha1(+/-)) results in a hypocontractile cardiac phenotype. This observation was surprising and unexpected. In order to determine if calcium overload contributes to the depressed phenotype, cardiac performance was examined by perfusing the hearts with buffer containing 2 or 1.5 mM calcium. At 2 mM calcium, +dP/dt for the alpha1(+/-) hearts (1374 +/- 180) was significantly less than that of wild-type (2656 +/- 75, P < 0.05). At 1.5 mM calcium, a larger decrease in +dP/dt occurred (vs. 2 mM calcium) for the alpha1(+/-) hearts (517 +/- 92) compared to wild-type (2238 +/- 157). At 2 mM calcium, -dP/dt was 50% lower in alpha1(+/-) hearts (-1903 +/- 141) than wild-type (-982 +/- 143). At 1.5 mM calcium relaxation was further reduced in alpha1(+/-) compared to wild-type (-443 +/- 56 vs. - 1691 +/- 109). We also tested whether the compensatory upregulation of the Na,K-ATPase alpha2 isoform in the alpha1(+/-) hearts contributes to the hypocontractile phenotype. At 8 x 10(-6) M ouabain, that would completely inhibit the alpha2 isoform, a 30% increase in contractility was obtained in alpha1(+/-) hearts compared to no ouabain treatment, while a 63% faster time-to-peak (TTP) and 67% faster half-time-to-relaxation (RT(1/2)) were observed in alpha1(+/-) hearts treated with ouabain. These results suggest that upregulation of the alpha2 isoform may play a role in slower TTP and RT(1/2) in the alpha1(+/-) hearts. Furthermore, lowering extracellular calcium in the perfusate did not alleviate the depressed contractile phenotype in the alpha1(+/-) hearts and resulted in further depressed cardiac contractility suggesting that these hearts are not calcium overloaded.

  18. In vitro effects of binuclear (η (6)-p-cymene)ruthenium(II) complex containing bridging bis(nicotinate)-polyethylene glycol ester ligand on differentiation pathways of murine Th lymphocytes activated by T cell mitogen.

    PubMed

    Momcilovic, Miljana; Eichhorn, Thomas; Blazevski, Jana; Schmidt, Harry; Kaluđerović, Goran N; Stosic-Grujicic, Stanislava

    2015-04-01

    T cell differentiation into distinct T helper (Th) subpopulations is crucial in governing acquired immune responses as well as some inflammatory and autoimmune disorders. This study investigated potential of the novel neutral binuclear ruthenium(II) complexes 1-8 with general formula [{RuCl2(η(6)-p-cym)}2μ-(N(∩)N)] (N(∩)N = bis(nicotinate)- and bis(iso-nicotinate)-polyethylene glycol esters; (3-py)COO(CH2CH2O) n CO(3-py) and (4-py)COO(CH2CH2O) n CO(4-py); n = 1-4), as well as [RuCl2(η(6)-p-cym)(nic)] (R1, nic = nicotinate) and [RuCl2(η(6)-p-cym)(inic)] (R2, inic = isonicotinate) as an immunomodulatory agents capable to direct Th cell differentiation. From all investigated complexes, [{RuCl2(η(6)-p-cym)}2μ-{(3-py)COO(CH2CH2O)4CO(3-py)}] (4) was selected for further study because it did not affect splenocyte viability (in concentration up to 50 μM), but significantly reduced secretion of representative Th1 cytokine, IFN-γ induced by T cell mitogen. Besides IFN-γ, 4 inhibited dose dependently expression and production of representative Th17 cytokine, IL-17, in these cells. Otherwise, the production of anti-inflammatory cytokines IL-4 and IL-10 was upregulated. Also, 4 significantly increased CD4(+)CD25(+)FoxP3(+) Treg cell frequency in the activated splenocytes. Moreover, ConA-induced expression of Th1 transcription factors, T-bet and STAT1, as well as of Th17-related protein STAT3 was attenuated upon exposure to 4, while the expression of Th2-related transcription factor GATA3 remained stable. In conclusion, ruthenium(II) complex 4 modulates immune system cell functions in vitro by inhibiting T cell differentiation towards pathogenic Th1/Th17 phenotype and inducing a regulatory phenotype characterized by IL-10 and IL-4 production, which may provide novel therapeutic opportunities for immune-inflammatory and/or autoimmune disorders.

  19. Linkage analysis of a new locus for autosomal recessive retinitis pigmentosa (arRP) on chromosome 6p

    SciTech Connect

    Shugart, Y.Y.; Knowles, J.A.; Banerjee, P.

    1994-09-01

    We report the localization of the arRP gene segregating in a large kindred from the Dominican Republic and the progress in refining the arRP region. The arRP gene in this family was found to be closely linked to markers D6S291, D6S273 with lod scores of 6.75, 3.08 at {theta}=0, 0.08, respectively. Since it was suggested that mutant peripherin causes arRP on 6p, we typed marker RDS1 at the peripherin-rds locus and detected four recombinants. More markers have been typed to further refine the location of arRP. Lod scores of 5.31. 5.89 and 2.05 were obtained with D6S439, UT722 and D6S426 at {theta}=0, 0, and 0.14, respectively. Some of the new markers were not included in the Genethon map, thus we used the CEPH (V7.0) data to order markers D6S273, D6S439, UT722, D6S426 and to estimate the recombination fractions as well as the ratios of female to male map distance. The best supported order is: D6S273 - D6S439 - D6S291 - UT722 - D6S426. Multipoint analyses were performed with the markers D6S273 - ({theta}{sub m}=0.0-21) - D6S439 - ({theta}{sub m}=0.066) - D6S426 with a constant sex ratio of 2.749. A maximum lod score of 9.74 was obtained at the marker D6S439. In conclusion, the most likely location for the arRP gene in the Dominican pedigree is approximately 20 centimorgans (cM) telomeric from peripherin.

  20. Bi–Mn mixed metal organic oxide: A novel 3d-6p mixed metal coordination network

    SciTech Connect

    Shi, Fa-Nian; Rosa Silva, Ana; Bian, Liang

    2015-05-15

    A new terminology of metal organic oxide (MOO) was given a definition as a type of coordination polymers which possess the feature of inorganic connectivity between metals and the direct bonded atoms and show 1D, 2D or 3D inorganic sub-networks. One such compound was shown as an example. A 3d-6p (Mn–Bi. Named MOOMnBi) mixed metals coordination network has been synthesized via hydrothermal method. The new compound with the molecular formula of [MnBi{sub 2}O(1,3,5-BTC){sub 2}]{sub n} (1,3,5-BTC stands for benzene-1,3,5-tricarboxylate) was characterized via single crystal X-ray diffraction technique that revealed a very interesting 3-dimensional (3D) framework with Bi{sub 4}O{sub 2}(COO){sub 12} clusters which are further connected to Mn(COO){sub 6} fragments into a 2D MOO. The topology study indicates an unprecedented topological type with the net point group of (4{sup 13}.6{sup 2})(4{sup 13}.6{sup 8})(4{sup 16}.6{sup 5})(4{sup 18}.6{sup 10})(4{sup 22}.6{sup 14})(4{sup 3}) corresponding to 3,6,7,7,8,9-c hexa-nodal net. MOOMnBi shows catalytic activity in the synthesis of (E)-α,β-unsaturated ketones. - Graphical abstract: This metal organic framework (MOF) is the essence of a 2D metal organic oxide (MOO). - Highlights: • New concept of metal organic oxide (MOO) was defined and made difference from metal organic framework. • New MOO of MOOMnBi was synthesized by hydrothermal method. • Crystal structure of MOOMnBi was determined by single crystal X-ray analysis. • The catalytic activity of MOOMnBi was studied showing reusable after 2 cycles.

  1. Differential effects of heme oxygenase isoforms on heme mediation of endothelial intracellular adhesion molecule 1 expression.

    PubMed

    Wagener, F A; da Silva, J L; Farley, T; de Witte, T; Kappas, A; Abraham, N G

    1999-10-01

    Heme oxygenase (HO), by catabolizing heme to bile pigments, down-regulates cellular hemoprotein, hemoglobin, and heme; the latter generates pro-oxidant products, including free radicals. Two HO isozymes, the products of distinct genes, have been described; HO-1 is the inducible isoform, whereas HO-2 is suggested to be constitutively expressed. We studied the inducing effect of several metal compounds (CoCl(2), stannic mesoporphyrin, and heme) on HO activity. Additionally, we studied HO-1 expression in experimental models of adhesion molecule expression produced by heme in endothelial cells, and the relationship of HO-1 expression to the induced adhesion molecules. Flow cytometry analysis showed that heme induces intracellular adhesion molecule 1 (ICAM-1) expression in a concentration (10-100 microM)- and time (1-24 h)-dependent fashion in human umbilical vein endothelial cells. Pretreatment with stannic mesoporphyrin, an inhibitor of HO activity, caused a 2-fold increase in heme-induced ICAM-1 expression. In contrast, HO induction by CoCl(2) decreased heme-induced ICAM-1 expression by 33%. To examine the contribution of HO-1 and HO-2 to endothelial HO activity, specific antisense oligonucleotides (ODNs) of each isoform were tested for their specificity to inhibit HO activity in cells exposed to heme. Endothelial cells exposed to heme elicited increased HO activity, which was prevented (70%) by HO-1 antisense ODNs. HO-2 antisense ODN inhibited heme-induced HO activity by 21%. Addition of HO-1 antisense ODNs prevented heme degradation and resulted in elevation of microsomal heme. Western blot analysis showed that HO-1 antisense ODNs selectively inhibited HO-1 protein and failed to inhibit HO-2 protein. Incubation of endothelial cells with HO-1 antisense enhanced heme-dependent increase of ICAM-1. In contrast, addition of HO-2 antisense to endothelial cells failed to increase adhesion molecules. The role of glutathione, an important antioxidant, was examined on heme

  2. Control of electronic magnetic state population via light polarization in the 5p 3/2 \\rightarrow 6p 3/2 electric quadrupole transition in atomic rubidium

    NASA Astrophysics Data System (ADS)

    Mojica-Casique, C.; Ponciano-Ojeda, F.; Hernández-Gómez, S.; López-Hernández, O.; Flores-Mijangos, J.; Ramírez-Martínez, F.; Sahagún, D.; Jáuregui, R.; Jiménez-Mier, J.

    2017-01-01

    Doppler-free optical double-resonance spectroscopy is used to study the 5{s}1/2\\to 5{p}3/2\\to 6{p}3/2 excitation sequence in room-temperature rubidium atoms. This involves a 5{s}1/2\\to 5{p}3/2 electric dipole preparation step followed by the 5{p}3/2\\to 6{p}3/2 electric quadrupole excitation. A detailed experimental and theoretical study of the dependance on the excitation beams polarization from the 420 nm decay fluorescence (6{p}3/2\\to 5{s}1/2) is presented. When a circularly polarized preparation beam is used, it produces a strongly oriented 5{p}3/2 intermediate state. In this case a linear quadrupole excitation beam transfers the oriented state to the 6{p}3/2 hyperfine states. For linearly polarized preparation and quadrupole excitation beams the spectra of the 6{p}3/2 hyperfine lines follow a cosine squared dependence on the angle between the polarization directions. As a consequence, it is shown that the choice of polarization configuration allows direct use of the electric quadrupole transition selection rules to control the populations of the 6{p}3/2 hyperfine magnetic sublevels in the absence of external fields. This is achieved by independently enhancing or suppressing either {{Δ }}{M}F=+/- 1 or ±2 electric quadrupole transitions.

  3. Functional impact of splice isoform diversity in individual cells

    PubMed Central

    Yap, Karen; Makeyev, Eugene V.

    2016-01-01

    Alternative pre-mRNA splicing provides an effective means for expanding coding capacity of eukaryotic genomes. Recent studies suggest that co-expression of different splice isoforms may increase diversity of RNAs and proteins at a single-cell level. A pertinent question in the field is whether such co-expression is biologically meaningful or, rather, represents insufficiently stringent splicing regulation. Here we argue that isoform co-expression may produce functional outcomes that are difficult and sometimes impossible to achieve using other regulation strategies. Far from being a ‘splicing noise’, co-expression is often established through co-ordinated activity of specific cis-elements and trans-acting factors. Further work in this area may uncover new biological functions of alternative splicing (AS) and generate important insights into mechanisms allowing different cell types to attain their unique molecular identities. PMID:27528755

  4. Disulfide isoforms of recombinant glia maturation factor beta.

    PubMed

    Zaheer, A; Lim, R

    1990-09-14

    Recombinant human glia maturation factor beta (r-hGMF-beta) is a single-chain polypeptide (141 amino acid residues) containing three cysteines, at positions 7, 86 and 95. Nascent r-hGMF-beta exists in the reduced state and has no biological activity. The protein can be activated through oxidative refolding by incubation with a mixture of reduced and oxidized glutathione. Reverse-phase HPLC analysis of the refolded r-hGMF-beta shows the presence of four peaks, corresponding to the reduced form plus three newly generated intrachain disulfide-containing isoforms predicted from the number of cysteine residues. Only one isoform shows biological activity when tested for growth suppression on C6 glioma cells. We infer from the HPLC elution pattern that the active form contains the disulfide bridge Cys86-Cys95.

  5. AMPK beta subunits display isoform specific affinities for carbohydrates.

    PubMed

    Koay, Ann; Woodcroft, Ben; Petrie, Emma J; Yue, Helen; Emanuelle, Shane; Bieri, Michael; Bailey, Michael F; Hargreaves, Mark; Park, Jong-Tae; Park, Kwan-Hwa; Ralph, Stuart; Neumann, Dietbert; Stapleton, David; Gooley, Paul R

    2010-08-04

    AMP-activated protein kinase (AMPK) is a heterotrimer of catalytic (alpha) and regulatory (beta and gamma) subunits with at least two isoforms for each subunit. AMPK beta1 is widely expressed whilst AMPK beta2 is highly expressed in muscle and both beta isoforms contain a mid-molecule carbohydrate-binding module (beta-CBM). Here we show that beta2-CBM has evolved to contain a Thr insertion and increased affinity for glycogen mimetics with a preference for oligosaccharides containing a single alpha-1,6 branched residue. Deletion of Thr-101 reduces affinity for single alpha-1,6 branched oligosaccharides by 3-fold, while insertion of this residue into the equivalent position in the beta1-CBM sequence increases affinity by 3-fold, confirming the functional importance of this residue.

  6. Functional impact of splice isoform diversity in individual cells.

    PubMed

    Yap, Karen; Makeyev, Eugene V

    2016-08-15

    Alternative pre-mRNA splicing provides an effective means for expanding coding capacity of eukaryotic genomes. Recent studies suggest that co-expression of different splice isoforms may increase diversity of RNAs and proteins at a single-cell level. A pertinent question in the field is whether such co-expression is biologically meaningful or, rather, represents insufficiently stringent splicing regulation. Here we argue that isoform co-expression may produce functional outcomes that are difficult and sometimes impossible to achieve using other regulation strategies. Far from being a 'splicing noise', co-expression is often established through co-ordinated activity of specific cis-elements and trans-acting factors. Further work in this area may uncover new biological functions of alternative splicing (AS) and generate important insights into mechanisms allowing different cell types to attain their unique molecular identities.

  7. 5-lipoxygenase mRNA and protein isoforms.

    PubMed

    Ochs, Meike J; Suess, Beatrix; Steinhilber, Dieter

    2014-01-01

    5-Lipoxygenase (5-LO) catalyses the two initial steps in the biosynthesis of leukotrienes, a group of inflammatory lipid mediators derived from arachidonic acid. An increased level of leukotrienes is associated with chronic inflammatory diseases such as asthma or atherosclerosis. In this MiniReview, we focus on recent findings regarding alternative splice variants of 5-LO with a special emphasis on two potential protein isoforms expressed in human B-lymphocytes which might be of interest as new drug targets.

  8. Gene Isoform Specificity through Enhancer-Associated Antisense Transcription

    PubMed Central

    Onodera, Courtney S.; Underwood, Jason G.; Katzman, Sol; Jacobs, Frank; Greenberg, David; Salama, Sofie R.; Haussler, David

    2012-01-01

    Enhancers and antisense RNAs play key roles in transcriptional regulation through differing mechanisms. Recent studies have demonstrated that enhancers are often associated with non-coding RNAs (ncRNAs), yet the functional role of these enhancer:ncRNA associations is unclear. Using RNA-Sequencing to interrogate the transcriptomes of undifferentiated mouse embryonic stem cells (mESCs) and their derived neural precursor cells (NPs), we identified two novel enhancer-associated antisense transcripts that appear to control isoform-specific expression of their overlapping protein-coding genes. In each case, an enhancer internal to a protein-coding gene drives an antisense RNA in mESCs but not in NPs. Expression of the antisense RNA is correlated with expression of a shorter isoform of the associated sense gene that is not present when the antisense RNA is not expressed. We demonstrate that expression of the antisense transcripts as well as expression of the short sense isoforms correlates with enhancer activity at these two loci. Further, overexpression and knockdown experiments suggest the antisense transcripts regulate expression of their associated sense genes via cis-acting mechanisms. Interestingly, the protein-coding genes involved in these two examples, Zmynd8 and Brd1, share many functional domains, yet their antisense ncRNAs show no homology to each other and are not present in non-murine mammalian lineages, such as the primate lineage. The lack of homology in the antisense ncRNAs indicates they have evolved independently of each other and suggests that this mode of lineage-specific transcriptional regulation may be more widespread in other cell types and organisms. Our findings present a new view of enhancer action wherein enhancers may direct isoform-specific expression of genes through ncRNA intermediates. PMID:22937057

  9. Isoform expression in the multiple soluble malate dehydrogenase of Hoplias malabaricus (Erythrinidae, Characiformes).

    PubMed

    Aquino-Silva, M R; Schwantes, M L; Schwantes, A R

    2003-02-01

    Kinetic properties and thermal stabilities of Hoplias malabaricus liver and skeletal muscle unfractionated malate dehydrogenase (MDH, EC 1.1.1.37) and its isolated isoforms were analyzed to further study the possible sMDH-A* locus duplication evolved from a recent tandem duplication. Both A (A1 and A2) and B isoforms had similar optima pH (7.5-8.0). While Hoplias A isoform could not be characterized as thermostable, B could as thermolabile. A isoforms differed from B isoform in having higher Km values for oxaloacetate. The possibly duplicated A2 isoform showed higher substrate affinity than the A1. Hoplias duplicated A isoforms may influence the direction of carbon flow between glycolisis and gluconeogenesis.

  10. The alternative translated MDMXp60 isoform regulates MDM2 activity

    PubMed Central

    Tournillon, Anne-Sophie; López, Ignacio; Malbert-Colas, Laurence; Naski, Nadia; Olivares-Illana, Vanesa; Fåhraeus, Robin

    2015-01-01

    Isoforms derived from alternative splicing, mRNA translation initiation or promoter usage extend the functional repertoire of the p53, p63 and p73 genes family and of their regulators MDM2 and MDMX. Here we show cap-independent translation of an N-terminal truncated isoform of hMDMX, hMDMXp60, which is initiated at the 7th AUG codon downstream of the initiation site for full length hMDMXFL at position +384. hMDMXp60 lacks the p53 binding motif but retains the RING domain and interacts with hMDM2 and hMDMXFL. hMDMXp60 shows higher affinity for hMDM2, as compared to hMDMXFL. In vitro data reveal a positive cooperative interaction between hMDMXp60 and hMDM2 and in cellulo data show that low levels of hMDMXp60 promote degradation of hMDM2 whereas higher levels stabilize hMDM2 and prevent hMDM2-mediated degradation of hMDMXFL. These results describe a novel alternatively translated hMDMX isoform that exhibits unique regulatory activity toward hMDM2 autoubiquitination. The data illustrate how the N-terminus of hMDMX regulates its C-terminal RING domain and the hMDM2 activity. PMID:25659040

  11. Immunogenicity of HIV-1 IIIB and SHIV 89.6P Tat and Tat toxoids in rhesus macaques: induction of humoral and cellular immune responses.

    PubMed

    Richardson, Max W; Mirchandani, Jyotika; Silvera, Peter; Régulier, Emmanuel G; Capini, Christelle; Bojczuk, Paul M; Hu, Jason; Gracely, Edward J; Boyer, Jean D; Khalili, Kamel; Zagury, Jean-François; Lewis, Mark G; Rappaport, Jay

    2002-09-01

    This study compared immune responses in rhesus macaques immunized with unmodified HIV-1 IIIB Tat, SHIV89.6P Tat, and carboxymethylated IIIB and 89.6P Tat toxoids. Immunization with either IIIB or 89.6P preparation induced high titer and broadly crossreactive serum anti-Tat IgG that recognized HIV-1 subtype-E and SIVmac251 Tat. However, the response was delayed, and titers were lower in 89.6P vaccination groups. Serum anti-Tat IgG recognized peptides corresponding to the amino-terminus, basic domain, and carboxy-terminal region. Cellular proliferative responses to Tat toxoids corresponding to the immunogen were evident in vitro in both IIIB and 89.6P groups. Crossreactive proliferative responses were observed in IIIB groups in response to stimulation with 89.6P or SIVmac251 Tat toxoids, but were much less prevalent in 89.6P groups. The truncated 86 amino acid IIIB Tat appears to be more immunogenic than the 102 amino acid 89.6P Tat with respect to both humoral and cellular immune responses, and may be a better vaccine component. Despite induction of robust humoral and cellular immune responses (including both CD4+ and CD8+ T-cell responses) to Tat, all animals were infected upon intravenous challenge with 30 MID(50) of SHIV89.6P and outcome of vaccine groups was not different from controls. Sequencing both Tat exons from serum viral RNA revealed no evidence of escape mutants. These results suggest that with intravenous SHIV89.6P challenge in rhesus macaques, precipitous CD4+ T-cell decline overwhelms potentially protective immune responses. Alternatively, Tat specific CD8+ T-cell responses may not appropriately recognize infected cells in vivo in this model. In view of evidence demonstrating Tat specific CTLs in the SIV model and in humans infected with HIV-1, results in this pathogenic SHIV model may not apparently predict the efficacy of this approach in human studies. The potency and cross-reactivity of these immune responses confirm Tat toxoid as an excellent

  12. Acidosis-mediated regulation of the NHE1 isoform of the Na⁺/H⁺ exchanger in renal cells.

    PubMed

    Odunewu, Ayodeji; Fliegel, Larry

    2013-08-01

    The mammalian Na⁺/H⁺ exchanger isoform 1 (NHE1) is a ubiquitous plasma membrane protein that regulates intracellular pH by removing a proton in exchange for extracellular sodium. Renal tissues are subject to metabolic and respiratory acidosis, and acidosis has been shown to acutely activate NHE1 activity in other cell types. We examined if NHE1 is activated by acute acidosis in HEK293 and Madin-Darby canine kidney (MDCK) cells. Acute sustained intracellular acidosis (SIA) activated NHE1 in both cell types. We expressed wild-type and mutant NHE1 cDNAs in MDCK cells. All the cDNAs had a L163F/G174S mutation, which conferred a 100-fold resistance to EMD87580, an NHE1-specific inhibitor. We assayed exogenous NHE1 activity while inhibiting endogenous activity with EMD87580 and while inhibiting the NHE3 isoform of the Na⁺/H⁺ exchanger using the isoform-specific inhibitor S3226. We examined the activation and phosphorylation of the wild-type and mutant NHE1 proteins in response to SIA. In MDCK cells we demonstrated that the amino acids Ser⁷⁷¹, Ser⁷⁷⁶, Thr⁷⁷⁹, and Ser⁷⁸⁵ are important for NHE1 phosphorylation and activation after acute SIA. SIA activated ERK-dependent pathways in MDCK cells, and this was blocked by treatment with the MEK inhibitor U0126. Treatment with U0126 also blocked activation of NHE1 by SIA. These results suggest that acute acidosis activates NHE1 in mammalian kidney cells and that in MDCK cells this activation occurs through an ERK-dependent pathway affecting phosphorylation of a distinct set of amino acids in the cytosolic regulatory tail of NHE1.

  13. Biochemical and enzymatic characterization of two basic Asp49 phospholipase A2 isoforms from Lachesis muta muta (Surucucu) venom.

    PubMed

    Damico, Daniela C S; Lilla, Sérgio; de Nucci, Gilberto; Ponce-Soto, Luis A; Winck, Flávia V; Novello, José Camillo; Marangoni, Sérgio

    2005-10-30

    Two basic phospholipase A2 (PLA2) isoforms were isolated from Lachesis muta muta snake venom and partially characterized. The venom was fractionated by molecular exclusion chromatography in ammonium bicarbonate buffer followed by reverse-phase HPLC on a C-18 mu-Bondapack column and RP-HPLC on a C-8 column. From liquid chromatography-electrospray ionization/mass spectrometry, the molecular mass of the two isoforms LmTX-I and LmTX-II was respectively measured as 14,245.4 and 14,186.2 Da. The pI was respectively estimated to be 8.7 and 8.6 for LmTX-I and LmTX-II, as determined by two-dimensional electrophoresis. The two proteins were sequenced and differentiated from each other by a single amino acid substitution, Arg65 (LmTX-I)-->Pro65 (LmTX-II). The amino acid sequence showed a high degree of homology between PLA2 isoforms from Lachesis muta muta and other PLA2 snake venoms. LmTX-I and LmTX-II had PLA2 activity in the presence of a synthetic substrate and showed a minimum sigmoidal behaviour; with maximal activity at pH 8.0 and 35-45 degrees C. Full PLA2 activity required Ca2+ and was respectively inhibited by Cu2+ and Zn2+ in the presence and absence of Ca2+. Crotapotin from Crotalus durissus cascavella rattlesnake venom significantly inhibited (P<0.05) the enzymatic activity of LmTX-I, suggesting that the binding site for crotapotin in this PLA2 was similar to another in the basic PLA2 of the crotoxin complex from C. durissus cascavella venom.

  14. Identification of a BRCA2-Specific Modifier Locus at 6p24 Related to Breast Cancer Risk

    PubMed Central

    Vijai, Joseph; Klein, Robert J.; Kirchhoff, Tomas; McGuffog, Lesley; Barrowdale, Daniel; Dunning, Alison M.; Lee, Andrew; Dennis, Joe; Healey, Sue; Dicks, Ed; Soucy, Penny; Sinilnikova, Olga M.; Pankratz, Vernon S.; Wang, Xianshu; Eldridge, Ronald C.; Tessier, Daniel C.; Vincent, Daniel; Bacot, Francois; Hogervorst, Frans B. L.; Peock, Susan; Stoppa-Lyonnet, Dominique; Peterlongo, Paolo; Schmutzler, Rita K.; Nathanson, Katherine L.; Piedmonte, Marion; Singer, Christian F.; Thomassen, Mads; Hansen, Thomas v. O.; Neuhausen, Susan L.; Blanco, Ignacio; Greene, Mark H.; Garber, Judith; Weitzel, Jeffrey N.; Andrulis, Irene L.; Goldgar, David E.; D'Andrea, Emma; Caldes, Trinidad; Nevanlinna, Heli; Osorio, Ana; van Rensburg, Elizabeth J.; Arason, Adalgeir; Rennert, Gad; van den Ouweland, Ans M. W.; van der Hout, Annemarie H.; Kets, Carolien M.; Aalfs, Cora M.; Wijnen, Juul T.; Ausems, Margreet G. E. M.; Frost, Debra; Ellis, Steve; Fineberg, Elena; Platte, Radka; Evans, D. Gareth; Jacobs, Chris; Adlard, Julian; Tischkowitz, Marc; Porteous, Mary E.; Damiola, Francesca; Golmard, Lisa; Barjhoux, Laure; Longy, Michel; Belotti, Muriel; Ferrer, Sandra Fert; Mazoyer, Sylvie; Spurdle, Amanda B.; Manoukian, Siranoush; Barile, Monica; Genuardi, Maurizio; Arnold, Norbert; Meindl, Alfons; Sutter, Christian; Wappenschmidt, Barbara; Domchek, Susan M.; Pfeiler, Georg; Friedman, Eitan; Jensen, Uffe Birk; Robson, Mark; Shah, Sohela; Lazaro, Conxi; Mai, Phuong L.; Benitez, Javier; Southey, Melissa C.; Schmidt, Marjanka K.; Fasching, Peter A.; Peto, Julian; Humphreys, Manjeet K.; Wang, Qin; Michailidou, Kyriaki; Sawyer, Elinor J.; Burwinkel, Barbara; Guénel, Pascal; Bojesen, Stig E.; Milne, Roger L.; Brenner, Hermann; Lochmann, Magdalena; Aittomäki, Kristiina; Dörk, Thilo; Margolin, Sara; Mannermaa, Arto; Lambrechts, Diether; Chang-Claude, Jenny; Radice, Paolo; Giles, Graham G.; Haiman, Christopher A.; Winqvist, Robert; Devillee, Peter; García-Closas, Montserrat; Schoof, Nils; Hooning, Maartje J.; Cox, Angela; Pharoah, Paul D. P.; Jakubowska, Anna; Orr, Nick; González-Neira, Anna; Pita, Guillermo; Alonso, M. Rosario; Hall, Per; Couch, Fergus J.; Simard, Jacques; Altshuler, David; Easton, Douglas F.; Chenevix-Trench, Georgia; Antoniou, Antonis C.; Offit, Kenneth

    2013-01-01

    Common genetic variants contribute to the observed variation in breast cancer risk for BRCA2 mutation carriers; those known to date have all been found through population-based genome-wide association studies (GWAS). To comprehensively identify breast cancer risk modifying loci for BRCA2 mutation carriers, we conducted a deep replication of an ongoing GWAS discovery study. Using the ranked P-values of the breast cancer associations with the imputed genotype of 1.4 M SNPs, 19,029 SNPs were selected and designed for inclusion on a custom Illumina array that included a total of 211,155 SNPs as part of a multi-consortial project. DNA samples from 3,881 breast cancer affected and 4,330 unaffected BRCA2 mutation carriers from 47 studies belonging to the Consortium of Investigators of Modifiers of BRCA1/2 were genotyped and available for analysis. We replicated previously reported breast cancer susceptibility alleles in these BRCA2 mutation carriers and for several regions (including FGFR2, MAP3K1, CDKN2A/B, and PTHLH) identified SNPs that have stronger evidence of association than those previously published. We also identified a novel susceptibility allele at 6p24 that was inversely associated with risk in BRCA2 mutation carriers (rs9348512; per allele HR = 0.85, 95% CI 0.80–0.90, P = 3.9×10−8). This SNP was not associated with breast cancer risk either in the general population or in BRCA1 mutation carriers. The locus lies within a region containing TFAP2A, which encodes a transcriptional activation protein that interacts with several tumor suppressor genes. This report identifies the first breast cancer risk locus specific to a BRCA2 mutation background. This comprehensive update of novel and previously reported breast cancer susceptibility loci contributes to the establishment of a panel of SNPs that modify breast cancer risk in BRCA2 mutation carriers. This panel may have clinical utility for women with BRCA2 mutations weighing options for medical

  15. Two ZNF509 (ZBTB49) isoforms induce cell-cycle arrest by activating transcription of p21/CDKN1A and RB upon exposure to genotoxic stress

    PubMed Central

    Jeon, Bu-Nam; Kim, Min-Kyeong; Yoon, Jae-Hyeon; Kim, Min-Young; An, Haemin; Noh, Hee-Jin; Choi, Won-Il; Koh, Dong-In; Hur, Man-Wook

    2014-01-01

    ZNF509 is unique among POK family proteins in that four isoforms are generated by alternative splicing. Short ZNF509 (ZNF509S1, -S2 and -S3) isoforms contain one or two out of the seven zinc-fingers contained in long ZNF509 (ZNF509L). Here, we investigated the functions of ZNF509 isoforms in response to DNA damage, showing isoforms to be induced by p53. Intriguingly, to inhibit proliferation of HCT116 and HEK293 cells, we found that ZNF509L activates p21/CDKN1A transcription, while ZNF509S1 induces RB. ZNF509L binds to the p21/CDKN1A promoter either alone or by interacting with MIZ-1 to recruit the co-activator p300 to activate p21/CDKN1A transcription. In contrast, ZNF509S1 binds to the distal RB promoter to interact and interfere with the MIZF repressor, resulting in derepression and transcription of RB. Immunohistochemical analysis revealed that ZNF509 is highly expressed in normal epithelial cells, but was completely repressed in tumor tissues of the colon, lung and skin, indicating a possible role as a tumor suppressor. PMID:25245946

  16. The Proportion of ALDEFLUOR-Positive Cancer Stem Cells Changes with Cell Culture Density Due to the Expression of Different ALDH Isoforms

    PubMed Central

    Opdenaker, Lynn M.; Modarai, Shirin R.; Boman, Bruce M.

    2017-01-01

    A significant number of discrepancies exist within the literature regarding ALDEFLUOR-positive stem cell populations in cell lines. We hypothesized that these inconsistencies resulted from differences in culture conditions, particularly cell density. We cultured several colon cancer cell lines (N=8) at high and low densities and found a significant decrease in ALDEFLUOR-positive cell populations at high density. However, we found no changes in the CD166-positive stem cell population, self-renewal, or cell cycle distribution of cells cultured at different densities. Interestingly, when we sorted both ALDEFLUOR positive and negative populations from the different density cultures, we identified a significant number of Aldehyde dehydrogenase (ALDH) isoforms whose expression was decreased in ALDEFLUOR-positive stem cells cultured at high density. This novel finding suggests that multiple ALDH isoforms contribute to ALDEFLUOR activity in colon cancer stem cells and decreases in ALDEFLUOR-positive stem cells at high cell density are due to decreased expression of multiple ALDH isoforms. Thus, designing therapeutics to target ALDEFLUOR-positive cancer stem cells may require inhibition of multiple ALDH isoforms.

  17. Protective efficacy of Anopheles minimus CYP6P7 and CYP6AA3 against cytotoxicity of pyrethroid insecticides in Spodoptera frugiperda (Sf9) insect cells.

    PubMed

    Duangkaew, P; Kaewpa, D; Rongnoparut, P

    2011-08-01

    Cytochrome P450 monooxygenases (P450s) are enzymes known to metabolize a wide variety of compounds including insecticides. Their overexpression leading to enhanced insecticide detoxification could result in insecticide resistance in insects. The increased mRNA expression of two P450 genes, CYP6P7 and CYP6AA3, has been previously observed in laboratory-selected deltamethrin-resistant Anopheles minimus, a major malaria vector in Southeast Asia, suggesting their role in detoxification of pyrethroids. In this study CYP6P7 and CYP6AA3 were expressed in insect Spodoptera frugiperda (Sf9) cells via baculovirusdirected expression system. Insecticide detoxification capabilities of Sf9 cells with and without expression of CYP6P7 or CYP6AA3 were evaluated using 3-(4,5-dimethyl-thiazol-2- yl)-2,5-diphenyltetrazolium bromide (MTT) assays. The results revealed that CYP6P7- or CYP6AA3-expressing cells showed significantly higher cytoprotective capability than parental Sf9 cells against cytotoxicity of pyrethroids including permethrin, cypermethrin and deltamethrin. Such cytoprotective effect was not observed for bioallethrin (pyrethroid), chlorpyrifos (organophosphate) and propoxur (carbamate). Moreover, expression of CYP6AA3, but not CYP6P7, could protect cells against λ-cyhalothrin cytotoxicity. In MTT assays upon co-incubation with piperonyl butoxide (P450 inhibitor), cytoprotective ability of CYP6P7 and CYP6AA3 against deltamethrin was diminished, implying that pyrethroid detoxification was due to activities of P450 enzymes. Insecticide detoxification capabilities of CYP6P7 and CYP6AA3 observed from MTT assays were correlated to their pyrethroid metabolizing activities observed from in vitro reconstitution enzymatic assays. Thus MTT assays using cells expressing P450 enzymes of interest could be primarily used to determine detoxification activities of enzymes against cytotoxic insecticides.

  18. Evaluation of the non-catalytic binding function of Ts26GST a glutathione transferase isoform of Taenia solium.

    PubMed

    Plancarte, A; Romero, J R; Nava, G; Reyes, H; Hernández, M

    2014-03-01

    Taenia solium glutathione transferase isoform of 26.5 kDa (Ts26GST) was observed to bind non-catalytically to porphyrins, trans-trans-dienals, bile acids and fatty acids, as assessed by inhibition kinetics, fluorescence spectroscopy and competitive fluorescence assays with 8-anilino-1-naphthalene sulfonate (ANS). The quenching of Ts26GST intrinsic fluorescence allowed for the determination of the dissociation constants (KD) for all ligands. Obtained data indicate that Ts26GST binds to all ligands but with different affinity. Porphyrins and lipid peroxide products inhibited Ts26GST catalytic activity up to 100% in contrast with only 20-30% inhibition observed for bile acids and two saturated fatty acids. Non-competitive type inhibition was observed for all enzyme inhibitor ligands except for trans-trans-2,4-decadienal, which exhibited uncompetitive type inhibition. The dissociation constant value KD = 0.7 μM for the hematin ligand, determined by competitive fluorescence assays with ANS, was in good agreement with its inhibition kinetic value Ki = 0.3 μM and its intrinsic fluorescence quenching KD = 0.7 μM. The remaining ligands did not displace ANS from the enzyme suggesting the existence of different binding sites. In addition to the catalytic activity of Ts26GST the results obtained suggest that the enzyme exhibits a ligandin function with broad specificity towards nonsubstrate ligands.

  19. Agonist-Specific Recruitment of Arrestin Isoforms Differentially Modify Delta Opioid Receptor Function

    PubMed Central

    Perroy, Julie; Walwyn, Wendy M.; Smith, Monique L.; Vicente-Sanchez, Ana; Segura, Laura; Bana, Alia; Kieffer, Brigitte L.; Evans, Christopher J.

    2016-01-01

    Ligand-specific recruitment of arrestins facilitates functional selectivity of G-protein-coupled receptor signaling. Here, we describe agonist-selective recruitment of different arrestin isoforms to the delta opioid receptor in mice. A high-internalizing delta opioid receptor agonist (SNC80) preferentially recruited arrestin 2 and, in arrestin 2 knock-outs (KOs), we observed a significant increase in the potency of SNC80 to inhibit mechanical hyperalgesia and decreased acute tolerance. In contrast, the low-internalizing delta agonists (ARM390, JNJ20788560) preferentially recruited arrestin 3 with unaltered behavioral effects in arrestin 2 KOs. Surprisingly, arrestin 3 KO revealed an acute tolerance to these low-internalizing agonists, an effect never observed in wild-type animals. Furthermore, we examined delta opioid receptor–Ca2+ channel coupling in dorsal root ganglia desensitized by ARM390 and the rate of resensitization was correspondingly decreased in arrestin 3 KOs. Live-cell imaging in HEK293 cells revealed that delta opioid receptors are in pre-engaged complexes with arrestin 3 at the cell membrane and that ARM390 strengthens this membrane interaction. The disruption of these complexes in arrestin 3 KOs likely accounts for the altered responses to low-internalizing agonists. Together, our results show agonist-selective recruitment of arrestin isoforms and reveal a novel endogenous role of arrestin 3 as a facilitator of resensitization and an inhibitor of tolerance mechanisms. SIGNIFICANCE STATEMENT Agonists that bind to the same receptor can produce highly distinct signaling events and arrestins are a major mediator of this ligand bias. Here, we demonstrate that delta opioid receptor agonists differentially recruit arrestin isoforms. We found that the high-internalizing agonist SNC80 preferentially recruits arrestin 2 and knock-out (KO) of this protein results in increased efficacy of SNC80. In contrast, low-internalizing agonists (ARM390 and JNJ20788560

  20. Stimulation of 14-3-3 protein and its isoform on histamine secretion from permeabilized rat peritoneal mast cells.

    PubMed

    Fujii, Toshihiro; Ueeda, Takayuki

    2002-12-01

    The effect of the 14-3-3 protein, an adaptor protein of intracellular signal pathways, on histamine release from rat peritoneal mast cells was investigated. The exogenous 14-3-3 protein from bovine brain increased the Ca(2+)-dependent histamine release from permeabilized mast cells, but only slightly affected the non-permeabilized cells. Partial amino acid sequences showed that the bovine brain 14-3-3 protein contained 14-3-3beta, gamma and zeta isoforms, and that these recombinant isoforms were prepared. Among them, 14-3-3zeta was an active species while the 14-3-3beta and gamma were inactive for histamine release from the permeabilized mast cells. Approximately 15% of the histamine release was stimulated by 14-3-3zeta at 2.5 microM, and half-maximal stimulation occurred at 1 microM. Treatment of the mast cells with wortmannin or staurosporine completely inhibited the stimulatory effect on histamine release caused by Ca(2+) or Ca(2+)/14-3-3zeta, and genistein partially inhibited both stimulatory effects. PD 98059, however, had little effect on the histamine release. These results suggest the possibility that 14-3-3zeta is associated with signal transduction for degranulation of the mast cells.

  1. Tumour cells can employ extracellular Ins(1,2,3,4,5,6)P(6) and multiple inositol-polyphosphate phosphatase 1 (MINPP1) dephosphorylation to improve their proliferation.

    PubMed

    Windhorst, Sabine; Lin, Hongying; Blechner, Christine; Fanick, Werner; Brandt, Laura; Brehm, Maria A; Mayr, Georg W

    2013-02-15

    InsP(6) [Ins(1,2,3,4,5,6)P6; phytate] is the most abundant inositol phosphate in mammalian cells with cytosolic/nuclear concentrations of up to 50 μM. We noticed that InsP6 in culture medium at a concentration of ≤50 μM significantly stimulates H1299 tumour cell growth, whereas larger concentrations of InsP6 inhibit growth. A detailed study of the fate of 30 μM InsP6 added to H199 cells revealed a major fraction of InsP6 initially precipitates as cell-surface metal complexes, but becomes slowly re-solubilized by extracellular dephosphorylation first to InsP3 isomers and subsequently to free myo-inositol. The precipitated metal-InsP6 complex is endocytosed in a receptor-independent but intact-glycocalyx-dependent manner and appears in lysosomes, where it is immediately dephosphorylated to Ins(1,2,4,5,6)P5 and very slowly to free inositol. By RNA knockdown, we identified secreted and lysosome targeted MINPP1 (multiple inositol-polyphosphate phosphatase 1), the mammalian 3-phytase, to be essentially involved both in extracellular and in lysosomal InsP6 dephosphorylation. The results of the present study indicate that tumour cells employ this enzyme to utilize the micronutrients myo-inositol and metal-phosphate when encountering extracellular InsP6 and thus to enhance their growth potential.

  2. Chirality Influence of Zaltoprofen Towards UDP-Glucuronosyltransferases (UGTs) Inhibition Potential.

    PubMed

    Jia, Lin; Hu, Cuimin; Wang, Haina; Liu, Yongzhe; Liu, Xin; Zhang, Yan-Yan; Li, Wei; Wang, Li-Xuan; Cao, Yun-Feng; Fang, Zhong-Ze

    2015-06-01

    Zaltoprofen (ZLT) is a nonsteroidal antiinflammation drug, and has been clinically employed to treat rheumatoid arthritis, osteoarthritis, and other chronic inflammatory pain conditions. The present study aims to investigate the chirality influence of zaltoprofen towards the inhibition potential towards UDP-glucuronosyltransferases (UGTs) isoforms. In vitro a recombinant UGT isoforms-catalyzed 4-methylumbelliferone (4-MU) glucuronidation incubation system was employed to investigate the inhibition of (R)-zaltoprofen and (S)-zaltoprofen towards UGT isoforms. The inhibition difference capability was observed for the inhibition of (R)-zaltoprofen and (S)-zaltoprofen towards UGT1A8 and UGT2B7, but not for other tested UGT isoforms. (R)-zaltoprofen exhibited noncompetitive inhibition towards UGT1A8 and competitive inhibition towards UGT2B7. The inhibition kinetic parameters were calculated to be 35.3 μM and 19.2 μM for UGT1A8 and UGT2B7. (R)-zaltoprofen and (S)-zaltoprofen exhibited a different inhibition type towards UGT1A7. Based on the reported maximum plasma concentration of (R)-zaltoprofen in vivo, a high drug-drug interaction between (R)-zaltoprofen and the drugs mainly undergoing UGT1A7, UGT1A8, and UGT2B7-catalyzed glucuronidation was indicated.

  3. Co-Expression of SERCA Isoforms, Phospholamban and Sarcolipin in Human Skeletal Muscle Fibers

    PubMed Central

    Fajardo, Val A.; Bombardier, Eric; Vigna, Chris; Devji, Tahira; Bloemberg, Darin; Gamu, Daniel; Gramolini, Anthony O.; Quadrilatero, Joe; Tupling, A. Russell

    2013-01-01

    Sarcolipin (SLN) and phospholamban (PLN) inhibit the activity of sarco(endo)plasmic reticulum Ca2+-ATPases (SERCAs) by reducing their apparent affinity for Ca2+. A ternary complex between SLN, PLN, and SERCAs results in super-inhibition of SERCA activity. Analysis of skeletal muscle homogenate has limited our current understanding of whether SLN and PLN regulate SERCA1a, SERCA2a, or both in skeletal muscle and whether SLN and PLN are co-expressed in skeletal muscle fibers. Biopsies from human vastus lateralis were analyzed through single fiber Western blotting and immunohisto/fluorescence staining to circumvent this limitation. With a newly generated SLN antibody, we report for the first time that SLN protein is present in human skeletal muscle. Addition of the SLN antibody (50 µg) to vastus lateralis homogenates increased the apparent Ca2+ affinity of SERCA (KCa, pCa units) (-Ab, 5.85 ± 0.02 vs. +Ab, 5.95 ± 0.02) and maximal SERCA activity (μmol/g protein/min) (-Ab, 122 ± 6.4 vs. +Ab, 159 ± 11) demonstrating a functional interaction between SLN and SERCAs in human vastus lateralis. Specifically, our results suggest that although SLN and PLN may preferentially regulate SERCA1a, and SERCA2a, respectively, physiologically they both may regulate either SERCA isoform. Furthermore, we show that SLN and PLN co-immunoprecipitate in human vastus lateralis homogenate and are simultaneously expressed in 81% of the fibers analyzed with Western blotting which implies that super-inhibition of SERCA may exist in human skeletal muscle. Finally, we demonstrate unequivocally that mouse soleus contains PLN protein suggesting that super-inhibition of SERCA may also be important physiologically in rodent skeletal muscle. PMID:24358354

  4. Capillary Isoelectric Focusing of Akt Isoforms Identifies Highly Dynamic Phosphorylation in Neuronal Cells and Brain Tissue*

    PubMed Central

    Schrötter, Sandra; Leondaritis, George; Eickholt, Britta J.

    2016-01-01

    The PI3K/PTEN/Akt pathway has been established as a core signaling pathway that is crucial for the integration of neurons into neuronal circuits and the maintenance of the architecture and function of neurons in the adult brain. Akt1–3 kinases are specifically activated by two phosphorylation events on residues Thr308 and Ser473 upon growth factor signaling, which subsequently phosphorylate a vast cohort of downstream targets. However, we still lack a clear understanding of the complexity and regulation of isoform specificity within the PI3K/PTEN/Akt pathway. We utilized a capillary-based isoelectric focusing method to study dynamics of Akt phosphorylation in neuronal cells and the developing brain and identify previously undescribed features of Akt phosphorylation and activation. First, we show that the accumulation of multiple phosphorylation events on Akt forms occur concurrently with Ser473 and Thr308 phosphorylation upon acute PI3K activation and provide evidence for uncoupling of Ser473 and Thr308 phosphorylation, as well as differential sensitivities of Akt1 forms upon PI3K inhibition. Second, we detect a transient shift in Akt isoform phosphorylation and activation pattern during early postnatal brain development, at stages corresponding to synapse development and maturation. Third, we show differential sensitivities of Ser473-Akt species to PTEN deletion in mature neurons, which suggests inherent differences in the Akt pools that are accessible to growth factors as compared with the pools that are controlled by PTEN. Our study demonstrates the presence of complex phosphorylation events of Akt in a time- and signal-dependent manner in neurons. PMID:26945062

  5. Capillary Isoelectric Focusing of Akt Isoforms Identifies Highly Dynamic Phosphorylation in Neuronal Cells and Brain Tissue.

    PubMed

    Schrötter, Sandra; Leondaritis, George; Eickholt, Britta J

    2016-05-06

    The PI3K/PTEN/Akt pathway has been established as a core signaling pathway that is crucial for the integration of neurons into neuronal circuits and the maintenance of the architecture and function of neurons in the adult brain. Akt1-3 kinases are specifically activated by two phosphorylation events on residues Thr(308) and Ser(473) upon growth factor signaling, which subsequently phosphorylate a vast cohort of downstream targets. However, we still lack a clear understanding of the complexity and regulation of isoform specificity within the PI3K/PTEN/Akt pathway. We utilized a capillary-based isoelectric focusing method to study dynamics of Akt phosphorylation in neuronal cells and the developing brain and identify previously undescribed features of Akt phosphorylation and activation. First, we show that the accumulation of multiple phosphorylation events on Akt forms occur concurrently with Ser(473) and Thr(308) phosphorylation upon acute PI3K activation and provide evidence for uncoupling of Ser(473) and Thr(308) phosphorylation, as well as differential sensitivities of Akt1 forms upon PI3K inhibition. Second, we detect a transient shift in Akt isoform phosphorylation and activation pattern during early postnatal brain development, at stages corresponding to synapse development and maturation. Third, we show differential sensitivities of Ser(473)-Akt species to PTEN deletion in mature neurons, which suggests inherent differences in the Akt pools that are accessible to growth factors as compared with the pools that are controlled by PTEN. Our study demonstrates the presence of complex phosphorylation events of Akt in a time- and signal-dependent manner in neurons.

  6. Acute and Chronic Mu Opioids Differentially Regulate Thrombospondins 1 and 2 Isoforms in Astrocytes

    PubMed Central

    2013-01-01

    Chronic opioids induce synaptic plasticity, a major neuronal adaptation. Astrocyte activation in synaptogenesis may play a critical role in opioid tolerance, withdrawal, and dependence. Thrombospondins 1 and 2 (TSP1/2) are astrocyte-secreted matricellular glycoproteins that promote neurite outgrowth as well as dendritic spine and synapse formation, all of which are inhibited by chronic μ opioids. In prior studies, we discovered that the mechanism of TSP1 regulation by μ opioids in astrocytes involves crosstalk between three different classes of receptors, μ opioid receptor, EGFR and TGFβR. Moreover, TGFβ1 stimulated TSP1 expression via EGFR and ERK/MAPK activation, indicating that EGFR is a signaling hub for opioid and TGFβ1 actions. Using various selective antagonists, and inhibitors, here we compared the mechanisms of chronic opioid regulation of TSP1/2 isoform expression in vivo and in immortalized rat cortical astrocytes. TSP1/2 release from astrocytes was also monitored. Acute and chronic μ opioids, morphine, and the prototypic μ ligand, DAMGO, modulated TSP2 protein levels. TSP2 but not TSP1 protein content was up-regulated by acute (3 h) morphine or DAMGO by an ERK/MAPK dependent mechanism. Paradoxically, TSP2 protein levels were altered neither by TGFβ1 nor by astrocytic neurotrophic factors, EGF, CNTF, and BMP4. TSP1/2 immunofluorescence was increased in astrocytes subjected to scratch-wounding, suggesting TSPs may be useful markers for the “reactive” state of these cells and potentially for different types of injury. Previously, we determined that chronic morphine attenuated both neurite outgrowth and synapse formation in cocultures of primary astrocytes and neurons under similar temporal conditions that μ opioids reduced TSP1 protein levels in astrocytes. Here we found that, after the same 8 day treatment, morphine or DAMGO diminished TSP2 protein levels in astrocytes. Therefore, μ opioids may deter synaptogenesis via both TSP1/2 isoforms

  7. Acute and chronic mu opioids differentially regulate thrombospondins 1 and 2 isoforms in astrocytes.

    PubMed

    Phamduong, Ellen; Rathore, Maanjot K; Crews, Nicholas R; D'Angelo, Alexander S; Leinweber, Andrew L; Kappera, Pranay; Krenning, Thomas M; Rendell, Victoria R; Belcheva, Mariana M; Coscia, Carmine J

    2014-02-19

    Chronic opioids induce synaptic plasticity, a major neuronal adaptation. Astrocyte activation in synaptogenesis may play a critical role in opioid tolerance, withdrawal, and dependence. Thrombospondins 1 and 2 (TSP1/2) are astrocyte-secreted matricellular glycoproteins that promote neurite outgrowth as well as dendritic spine and synapse formation, all of which are inhibited by chronic μ opioids. In prior studies, we discovered that the mechanism of TSP1 regulation by μ opioids in astrocytes involves crosstalk between three different classes of receptors, μ opioid receptor, EGFR and TGFβR. Moreover, TGFβ1 stimulated TSP1 expression via EGFR and ERK/MAPK activation, indicating that EGFR is a signaling hub for opioid and TGFβ1 actions. Using various selective antagonists, and inhibitors, here we compared the mechanisms of chronic opioid regulation of TSP1/2 isoform expression in vivo and in immortalized rat cortical astrocytes. TSP1/2 release from astrocytes was also monitored. Acute and chronic μ opioids, morphine, and the prototypic μ ligand, DAMGO, modulated TSP2 protein levels. TSP2 but not TSP1 protein content was up-regulated by acute (3 h) morphine or DAMGO by an ERK/MAPK dependent mechanism. Paradoxically, TSP2 protein levels were altered neither by TGFβ1 nor by astrocytic neurotrophic factors, EGF, CNTF, and BMP4. TSP1/2 immunofluorescence was increased in astrocytes subjected to scratch-wounding, suggesting TSPs may be useful markers for the "reactive" state of these cells and potentially for different types of injury. Previously, we determined that chronic morphine attenuated both neurite outgrowth and synapse formation in cocultures of primary astrocytes and neurons under similar temporal conditions that μ opioids reduced TSP1 protein levels in astrocytes. Here we found that, after the same 8 day treatment, morphine or DAMGO diminished TSP2 protein levels in astrocytes. Therefore, μ opioids may deter synaptogenesis via both TSP1/2 isoforms, but

  8. Variation in exposure to Anopheles gambiae salivary gland peptide (gSG6-P1) across different malaria transmission settings in the western Kenya highlands

    PubMed Central

    2012-01-01

    Background The existing metrics of malaria transmission are limited in sensitivity under low transmission intensity. Robust surveillance systems are needed as interventions to monitor reduced transmission and prevention of rapid reintroduction. Serological tools based on antibody responses to parasite and vector antigens are potential tools for transmission measurements. The current study sought to evaluate antibody responses to Anopheles gambiae salivary gland peptide (gSG6- P1), as a biomarker of human exposure to Anopheles bites, in different transmission settings and seasons. The comparison between anti-MSP-119 IgG immune responders and non-responders allowed exploring the robustness of the gSG6-P1 peptide as a surveillance tool in an area of decreasing malaria transmission. Methods Total IgG levels to gSG6-P1 were measured in an age-stratified cohort (< 5, 5–14 and ≥ 15 years) in a total of 1,366 participants from three localities in western Kenya [Kisii (hypoendemic), Kakamega (mesoendemic), and Kombewa (hyperendemic)] including 607 sera that were additionally tested for MSP-119 specific responses during a low and a high malaria transmission seasons. Antibody prevalence and levels were compared between localities with different transmission intensities. Regression analysis was performed to examine the association between gSG6-P1 and MSP-119 seroprevalence and parasite prevalence. Result Seroprevalence of gSG6-P1 in the uphill population was 36% while it was 50% valley bottom (χ2 = 13.2, df = 1, p < 0.001). Median gSG6-P1 antibody levels in the Valley bottom were twice as high as that observed in the uphill population [4.50 vs. 2.05, p < 0.001] and showed seasonal variation. The odds of gSG6-P1 seropositives having MSP-119 antibodies were almost three times higher than the odds of seronegatives (OR = 2.87, 95% CI [1.977, 4.176]). The observed parasite prevalence for Kisii, Kakamega and Kombewa were 4%, 19.7% and 44.6% whilst the

  9. The Cytochrome P450 gene CYP6P12 confers pyrethroid resistance in kdr-free Malaysian populations of the dengue vector Aedes albopictus

    PubMed Central

    Ishak, Intan H.; Riveron, Jacob M.; Ibrahim, Sulaiman S.; Stott, Rob; Longbottom, Joshua; Irving, Helen; Wondji, Charles S.

    2016-01-01

    Control of Aedes albopictus, major dengue and chikungunya vector, is threatened by growing cases of insecticide resistance. The mechanisms driving this resistance remain poorly characterised. This study investigated the molecular basis of insecticide resistance in Malaysian populations of Ae. albopictus. Microarray-based transcription profiling revealed that metabolic resistance (cytochrome P450 up-regulation) and possibly a reduced penetration mechanism (consistent over-expression of cuticular protein genes) were associated with pyrethroid resistance. CYP6P12 over-expression was strongly associated with pyrethroid resistance whereas CYP6N3 was rather consistently over-expressed across carbamate and DDT resistant populations. Other detoxification genes also up-regulated in permethrin resistant mosquitoes included a glucuronosyltransferase (AAEL014279-RA) and the glutathione-S transferases GSTS1 and GSTT3. Functional analyses further supported that CYP6P12 contributes to pyrethroid resistance in Ae. albopictus as transgenic expression of CYP6P12 in Drosophila was sufficient to confer pyrethroid resistance in these flies. Furthermore, molecular docking simulations predicted CYP6P12 possessing enzymatic activity towards pyrethroids. Patterns of polymorphism suggested early sign of selection acting on CYP6P12 but not on CYP6N3. The major role played by P450 in the absence of kdr mutations suggests that addition of the synergist PBO to pyrethroids could improve the efficacy of this insecticide class and overcome resistance in field populations of Ae. albopictus. PMID:27094778

  10. Observation of the 5 p3 /2→6 p3 /2 electric-dipole-forbidden transition in atomic rubidium using optical-optical double-resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Ponciano-Ojeda, F.; Hernández-Gómez, S.; López-Hernández, O.; Mojica-Casique, C.; Colín-Rodríguez, R.; Ramírez-Martínez, F.; Flores-Mijangos, J.; Sahagún, D.; Jáuregui, R.; Jiménez-Mier, J.

    2015-10-01

    Direct evidence of excitation of the 5 p3 /2→6 p3 /2 electric-dipole-forbidden transition in atomic rubidium is presented. The experiments were performed in a room-temperature rubidium cell with continuous-wave external cavity diode lasers. Optical-optical double-resonance spectroscopy with counterpropagating beams allows the detection of the nondipole transition free of Doppler broadening. The 5 p3 /2 state is prepared by excitation with a laser locked to the maximum F cyclic transition of the D2 line, and the forbidden transition is produced by excitation with a 911 nm laser. Production of the forbidden transition is monitored by detection of the 420 nm fluorescence that results from decay of the 6 p3 /2 state. Spectra with three narrow lines (≈13 MHz FWHM) with the characteristic F -1 , F , and F +1 splitting of the 6 p3 /2 hyperfine structure in both rubidium isotopes were obtained. The results are in very good agreement with a direct calculation that takes into account the 5 s →5 p3 /2 preparation dynamics, the 5 p3 /2→6 p3 /2 nondipole excitation geometry, and the 6 p3 /2→5 s1 /2 decay. The comparison also shows that the electric-dipole-forbidden transition is a very sensitive probe of the preparation dynamics.

  11. Oleanolic acid suppresses aerobic glycolysis in cancer cells by switching pyruvate kinase type M isoforms.

    PubMed

    Liu, Jia; Wu, Ning; Ma, Leina; Liu, Ming; Liu, Ge; Zhang, Yuyan; Lin, Xiukun

    2014-01-01

    Warburg effect, one of the hallmarks for cancer cells, is characterized by metabolic switch from mitochondrial oxidative phosphorylation to aerobic glycolysis. In recent years, increased expression level of pyruvate kinase M2 (PKM2) has been found to be the culprit of enhanced aerobic glycolysis in cancer cells. However, there is no agent inhibiting aerobic glycolysis by targeting PKM2. In this study, we found that Oleanolic acid (OA) induced a switch from PKM2 to PKM1, and consistently, abrogated Warburg effect in cancer cells. Suppression of aerobic glycolysis by OA is mediated by PKM2/PKM1 switch. Furthermore, mTOR signaling was found to be inactivated in OA-treated cancer cells, and mTOR inhibition is required for the effect of OA on PKM2/PKM1 switch. Decreased expression of c-Myc-dependent hnRNPA1 and hnRNPA1 was responsible for OA-induced switch between PKM isoforms. Collectively, we identified that OA is an antitumor compound that suppresses aerobic glycolysis in cancer cells and there is potential that PKM2 may be developed as an important target in aerobic glycolysis pathway for developing novel anticancer agents.

  12. An activation-induced IL-15 isoform is a natural antagonist for IL-15 function

    PubMed Central

    Zhao, Lei; Hu, Bo; Zhang, Yinsheng; Song, Yuan; Lin, Dandan; Liu, Yonghao; Mei, Yu; Sandikin, Dedy; Sun, Weiping; Zhuang, Min; Liu, Haiyan

    2016-01-01

    Interleukin 15 (IL-15) expression induces the secretion of inflammatory cytokines, inhibits the apoptosis of activated T cells and prolongs the survival of CD8+ memory T cells. Here we identified an IL-15 isoform lacking exon-6, IL-15ΔE6, generated by alternative splicing events of activated immune cells, including macrophages and B cells. In vitro study showed that IL-15ΔE6 could antagonize IL-15-mediated T cell proliferation. The receptor binding assay revealed that IL-15ΔE6 could bind to IL-15Rα and interfere with the binding between IL-15 and IL-15Rα. Over-expression of IL-15ΔE6 in the murine EAE model ameliorated the EAE symptoms of the mice. The clinical scores were significantly lower in the mice expressing IL-15ΔE6 than the control mice and the mice expressing IL-15. The inflammation and demyelination of the EAE mice expressing IL-15ΔE6 were less severe than the control group. Furthermore, flow cytometry analysis demonstrated that IL-15ΔE6 expression reduced the percentages of inflammatory T cells in the spleen and spinal cord, and inhibited the infiltration of macrophages to the CNS. Our results demonstrated that IL-15ΔE6 could be induced during immune activation and function as a negative feedback mechanism to dampen IL-15-mediated inflammatory events. PMID:27166125

  13. A novel histone deacetylase 1 and 2 isoform-specific inhibitor alleviates experimental Parkinson's disease.

    PubMed

    Choong, Chi-Jing; Sasaki, Tsutomu; Hayakawa, Hideki; Yasuda, Toru; Baba, Kousuke; Hirata, Yoshiyuki; Uesato, Shinichi; Mochizuki, Hideki

    2016-01-01

    With increased histone deacetylase (HDAC) activity and histone hypoacetylation being implicated in neurodegeneration, HDAC inhibitors have been reported to have considerable therapeutic potential. Yet, existing inhibitors lack specificity and may show substantial adverse effect. In this study, we identified a novel HDAC1/2 isoform-specific inhibitor, K560, with protective effects against 1-methyl-4-phenylpyridinium (MPP(+))- and/or 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neuronal death in both in vitro and in vivo Parkinson's disease model. K560 attenuated cell death induced by MPP(+) in differentiated SH-SY5Y cells through the sustained expression of an antiapoptotic protein, X-linked inhibitor of apoptosis (XIAP). Inhibition of XIAP expression by locked nucleic acid antisense oligonucleotides abolished the protective effect of K560. Inactivation of mitogen-activated protein kinase cascades, reduced p53 phosphorylation, and down-regulation of p53-upregulated modulator of apoptosis on K560 treatment were also observed. Furthermore, pre- and post-oral administration of K560 to mice prevented MPTP-induced loss of dopaminergic neurons in substantia nigra, suggesting that selective inhibition of HDAC1 and HDAC2 by K560 may pave the way to new strategies for Parkinson's disease treatment.

  14. Oleanolic Acid Suppresses Aerobic Glycolysis in Cancer Cells by Switching Pyruvate Kinase Type M Isoforms

    PubMed Central

    Ma, Leina; Liu, Ming; Liu, Ge; Zhang, Yuyan; Lin, Xiukun

    2014-01-01

    Warburg effect, one of the hallmarks for cancer cells, is characterized by metabolic switch from mitochondrial oxidative phosphorylation to aerobic glycolysis. In recent years, increased expression level of pyruvate kinase M2 (PKM2) has been found to be the culprit of enhanced aerobic glycolysis in cancer cells. However, there is no agent inhibiting aerobic glycolysis by targeting PKM2. In this study, we found that Oleanolic acid (OA) induced a switch from PKM2 to PKM1, and consistently, abrogated Warburg effect in cancer cells. Suppression of aerobic glycolysis by OA is mediated by PKM2/PKM1 switch. Furthermore, mTOR signaling was found to be inactivated in OA-treated cancer cells, and mTOR inhibition is required for the effect of OA on PKM2/PKM1 switch. Decreased expression of c-Myc-dependent hnRNPA1 and hnRNPA1 was responsible for OA-induced switch between PKM isoforms. Collectively, we identified that OA is an antitumor compound that suppresses aerobic glycolysis in cancer cells and there is potential that PKM2 may be developed as an important target in aerobic glycolysis pathway for developing novel anticancer agents. PMID:24626155

  15. Refining the map and defining flanking markers of the gene for autosomal recessive polycystic kidney disease on chromosome 6p21.1-p12

    SciTech Connect

    Muecher, G.; Wirth, B.; Zerres, K.

    1994-12-01

    Autosomal recessive polycystic kidney disease (ARPKD) is one of the most important hereditary nephropathies in childhood. The reported incidence is 1:6,000 - 1:40,000 live births. We recently mapped the gene for ARPKD to chromosome 6p21-cen by linkage analysis. In a more extensive study, we analyzed two additional microsatellite markers of the region 6p21 in 12 multiplex and 4 simplex ARPKD families, which have previously been published by Zerres et al. (1994). Because of additional typing, more families have become informative for single markers. 12 refs., 2 figs., 2 tabs.

  16. Cyclooxygenase Isoform Exchange Blocks Brain-Mediated Inflammatory Symptoms

    PubMed Central

    Mirrasekhian, Elahe; Zajdel, Joanna; Kumar Singh, Anand; Engblom, David

    2016-01-01

    Cyclooxygenase-2 (COX-2) is the main source of inducible prostaglandin E2 production and mediates inflammatory symptoms including fever, loss of appetite and hyperalgesia. COX-1 is dispensable for fever, anorexia and hyperalgesia but is important for several other functions both under basal conditions and during inflammation. The differential functionality of the COX isoforms could be due to differences in the regulatory regions of the genes, leading to different expression patterns, or to differences in the coding sequence, resulting in distinct functional properties of the proteins. To study the molecular underpinnings of the functional differences between the two isoforms in the context of inflammatory symptoms, we used mice in which the coding sequence of COX-2 was replaced by the corresponding sequence of COX-1. In these mice, COX-1 mRNA was induced by inflammation but COX-1 protein expression did not fully mimic inflammation-induced COX-2 expression. Just like mice globally lacking COX-2, these mice showed a complete lack of fever and inflammation-induced anorexia as well as an impaired response to inflammatory pain. However, as previously reported, they displayed close to normal survival rates, which contrasts to the high fetal mortality in COX-2 knockout mice. This shows that the COX activity generated from the hybrid gene was strong enough to allow survival but not strong enough to mediate the inflammatory symptoms studied, making the line an interesting alternative to COX-2 knockouts for the study of inflammation. Our results also show that the functional differences between COX-1 and COX-2 in the context of inflammatory symptoms are not only dependent on the features of the promoter regions. Instead they indicate that there are fundamental differences between the isoforms at translational or posttranslational levels. PMID:27861574

  17. PSA Isoforms' Velocities for Early Diagnosis of Prostate Cancer.

    PubMed

    Heidegger, Isabel; Klocker, Helmut; Pichler, Renate; Horninger, Wolfgang; Bektic, Jasmin

    2015-06-01

    Free prostate-specific antigen (fPSA) and its molecular isoforms are suggested for enhancement of PSA testing in prostate cancer (PCa). In the present study we evaluated whether PSA isoforms' velocities might serve as a tool to improve early PCa diagnosis. Our study population included 381 men who had undergone at least one ultrasound-guided prostate biopsy whose pathologic examination yielded PCa or showed no evidence of prostatic malignancy. Serial PSA, fPSA, and proPSA measurements were performed on serum samples covering 7 years prior to biopsy using Beckmann Coulter Access immunoassays. Afterwards, velocities of PSA (PSAV), fPSA% (fPSA%V), proPSA% (proPSA%V) and the ratio proPSA/PSA/V were calculated and their ability to discriminate cancer from benign disease was evaluated. Among 381 men included in the study, 202 (53%) were diagnosed with PCa and underwent radical prostatectomy at our Department. PSAV, fPSA%V, proPSA%V as well as proPSA/PSA/V were able to differentiate significantly between PCa and non-cancerous prostate. The highest discriminatory power between cancer and benign disease has been observed two and one year prior to diagnosis with all measured parameters. Among all measured parameters, fPSA%V showed the best cancer specificity of 45.3% with 90% of sensitivity. In summary, our results highlight the value of PSA isoforms' velocity for early detection of PCa. Especially fPSA%V should be used in the clinical setting to increase cancer detection specificity.

  18. H2O2-Sensitive Isoforms of Drosophila melanogaster TRPA1 Act in Bitter-Sensing Gustatory Neurons to Promote Avoidance of UV During Egg-Laying.

    PubMed

    Guntur, Ananya R; Gou, Bin; Gu, Pengyu; He, Ruo; Stern, Ulrich; Xiang, Yang; Yang, Chung-Hui

    2017-02-01

    The evolutionarily conserved TRPA1 channel can sense various stimuli including temperatures and chemical irritants. Recent results have suggested that specific isoforms of Drosophila TRPA1 (dTRPA1) are UV-sensitive and that their UV sensitivity is due to H2O2 sensitivity. However, whether such UV sensitivity served any physiological purposes in animal behavior was unclear. Here, we demonstrate that H2O2-sensitive dTRPA1 isoforms promote avoidance of UV when adult Drosophila females are selecting sites for egg-laying. First, we show that blind/visionless females are still capable of sensing and avoiding UV during egg-laying when intensity of UV is high yet within the range of natural sunlight. Second, we show that such vision-independent UV avoidance is mediated by a group of bitter-sensing neurons on the proboscis that express H2O2-sensitive dTRPA1 isoforms. We show that these bitter-sensing neurons exhibit dTRPA1-dependent UV sensitivity. Importantly, inhibiting activities of these bitter-sensing neurons, reducing their dTRPA1 expression, or reducing their H2O2-sensitivity all significantly reduced blind females' UV avoidance, whereas selectively restoring a H2O2-sensitive isoform of dTRPA1 in these neurons restored UV avoidance. Lastly, we show that specifically expressing the red-shifted channelrhodopsin CsChrimson in these bitter-sensing neurons promotes egg-laying avoidance of red light, an otherwise neutral cue for egg-laying females. Together, these results demonstrate a physiological role of the UV-sensitive dTRPA1 isoforms, reveal that adult Drosophila possess at least two sensory systems for detecting UV, and uncover an unexpected role of bitter-sensing taste neurons in UV sensing.

  19. Genome-wide RNAi screening identifies TMIGD3 isoform1 as a suppressor of NF-κB and osteosarcoma progression

    PubMed Central

    Iyer, Swathi V.; Ranjan, Atul; Elias, Harold K.; Parrales, Alejandro; Sasaki, Hiromi; Roy, Badal C.; Umar, Shahid; Tawfik, Ossama W.; Iwakuma, Tomoo

    2016-01-01

    The ability of cancer cells to survive and grow in anchorage- and serum-independent conditions is well correlated with their aggressiveness. Here, using a human whole-genome shRNA library, we identify TMIGD3 isoform1 (i1) as a factor that suppresses this ability in osteosarcoma (OS) cells, mainly by inhibiting NF-κB activity. Knockdown of TMIGD3 increases proliferation, tumour formation and metastasis of OS cells. Overexpression of TMIGD3 isoform1 (i1), but not isoform3 (i3) which shares a common C-terminal region, suppresses these malignant properties. Adenosine A3 receptor (A3AR) having an identical N-terminal region shows similar biological profiles to TMIGD3 i1. Protein expression of TMIGD3 and A3AR is lower in human OS tissues than normal tissues. Mechanistically, TMIGD3 i1 and A3AR commonly inhibit the PKA−Akt−NF-κB axis. However, TMIGD3 i1 only partially rescues phenotypes induced by A3AR knockdown, suggesting the presence of distinct pathways. Our findings reveal an unappreciated role for TMIGD3 i1 as a suppressor of NF-κB activity and OS progression. PMID:27886186

  20. Saint John's wort, an herbal inducer of the cytochrome P4503A4 isoform, may alleviate symptoms of Willis-Ekbom's disease

    PubMed Central

    Pereira, José Carlos; Pradella-Hallinan, Márcia; Alves, Rosana Cardoso

    2013-01-01

    OBJECTIVE: Certain drug classes alleviate the symptoms of Willis-Ekbom's disease, whereas others aggravate them. The pharmacological profiles of these drugs suggest that drugs that alleviate Willis-Ekbom's disease inhibit thyroid hormone activity, whereas drugs that aggravate Willis-Ekbom's disease increase thyroid hormone activity. These different effects may be secondary to the opposing actions that drugs have on the CYP4503A4 enzyme isoform. Drugs that worsen the symptoms of the Willis-Ekbom's disease inhibit the CYP4503A4 isoform, and drugs that ameliorate the symptoms induce CYP4503A4. The aim of this study is to determine whether Saint John's wort, as an inducer of the CYP4503A4 isoform, diminishes the severity of Willis-Ekbom's disease symptoms by increasing the metabolism of thyroid hormone in treated patients. METHODS: In an open-label pilot trial, we treated 21 Willis-Ekbom's disease patients with a concentrated extract of Saint John's wort at a daily dose of 300 mg over the course of three months. RESULTS: Saint John's wort reduced the severity of Willis-Ekbom's disease symptoms in 17 of the 21 patients. CONCLUSION: Results of this trial suggest that Saint John's wort may benefit some Willis-Ekbom's disease patients. However, as this trial was not placebo-controlled, the extent to which Saint John's wort is effective as a Willis-Ekbom's disease treatment will depend on future, blinded placebo-controlled studies. PMID:23778343

  1. Separation of arginase isoforms by capillary zone electrophoresis and isoelectric focusing in density gradient column.

    PubMed

    Pedrosa, M M; Legaz, M E

    1995-04-01

    Four major arginase isoforms, I, II, III and IV, have been detected in Evernia prunastri thallus. They differ in terms of both physical and biochemical properties. The isoelectric point (pI) of these proteins has been determined by both isoelectric focusing in density gradient column and high-performance capillary electrophoresis (HPCE). Isoelectric focusing revealed charge microheterogeneity for isoforms II and IV whereas arginases I and II had the same pI value of 5.8. HPCE separation confirmed this charge microheterogeneity for isoform IV but not for isoform III, and provided evidence of microheterogeneity for isoforms I and II. The effect of various electrolyte buffers and running conditions on the HPCE separation of arginase isoform were investigated. Addition of 0.5 mM spermidine (SPD) to the running buffer reduced the electroosmotic flow (EOF) and permitted discriminating between the native proteins and protein fragments.

  2. Evolutionary, environmental and tissue controls on the occurrence of multiple isoforms of acyl carrier protein

    SciTech Connect

    Battey, J.F.; Ohlrogge, J.B. )

    1989-04-01

    Previous research has revealed that several higher plant species have multiple isoforms of acyl carrier protein (ACP). We have examined the development of this trait in evolutionarily diverse species. Isoforms were resolved by Western blotting and native PAGE of {sup 3}H-palmitate labelled ACP's. Multiple isoforms of ACP were observed in primitive vascular plants including gymnosperms, ferns and Psilotum and the nonvascular liverworts and mosses. Therefore, the development of ACP isoforms occurred early in evolution. However, unicellular algae and bacteria such as Chlamydomonas, Dunaliella, Synechocystis and Agmnellum have only a single electrophoretic form of ACP. Thus, multiple forms of ACP do not occur in all photosynthetic organisms but may be associated with multicellular plants. We have also examined light and tissue control over the expression of ACP isoforms. The expression of multiple forms of ACP in leaf of Spinacia and Avena is altered very little by light. Rather, the different patterns of ACP isoforms are primarily dependant on tissue source.

  3. Identification of signals that facilitate isoform specific nucleolar localization of myosin IC

    SciTech Connect

    Schwab, Ryan S.; Ihnatovych, Ivanna; Yunus, Sharifah Z.S.A.; Domaradzki, Tera; Hofmann, Wilma A.

    2013-05-01

    Myosin IC is a single headed member of the myosin superfamily that localizes to the cytoplasm and the nucleus, where it is involved in transcription by RNA polymerases I and II, intranuclear transport, and nuclear export. In mammalian cells, three isoforms of myosin IC are expressed that differ only in the addition of short isoform-specific N-terminal peptides. Despite the high sequence homology, the isoforms show differences in cellular distribution, in localization to nuclear substructures, and in their interaction with nuclear proteins through yet unknown mechanisms. In this study, we used EGFP-fusion constructs that express truncated or mutated versions of myosin IC isoforms to detect regions that are involved in isoform-specific localization. We identified two nucleolar localization signals (NoLS). One NoLS is located in the myosin IC isoform B specific N-terminal peptide, the second NoLS is located upstream of the neck region within the head domain. We demonstrate that both NoLS are functional and necessary for nucleolar localization of specifically myosin IC isoform B. Our data provide a first mechanistic explanation for the observed functional differences between the myosin IC isoforms and are an important step toward our understanding of the underlying mechanisms that regulate the various and distinct functions of myosin IC isoforms. - Highlights: ► Two NoLS have been identified in the myosin IC isoform B sequence. ► Both NoLS are necessary for myosin IC isoform B specific nucleolar localization. ► First mechanistic explanation of functional differences between the isoforms.

  4. Expression of CD44 isoforms in renal cell tumors. Positive correlation to tumor differentiation.

    PubMed Central

    Terpe, H. J.; Störkel, S.; Zimmer, U.; Anquez, V.; Fischer, C.; Pantel, K.; Günthert, U.

    1996-01-01

    CD44 isoforms have been implicated in tumor progression and embryogenesis. Primary renal cell tumors (n = 100) of various histopathological differentiation and grading stages were analyzed for expression of CD44 isoforms in comparison with nonmalignant adult and fetal renal tissues. Evaluations were performed by immunohistochemistry using CD44 isoform-specific monoclonal antibodies and by reverse transcriptase polymerase chain reactions (RT-PCR). In the nonmalignant kidney no CD44 variant isoforms were detected. There was a significant increase in expression of CD44 standard (CD44s) and several variant isoforms (CD44v) in the course of tumor differentiation in clear cell carcinomas (n = 68) from stages G1 to G3 (P < 0.0001 for CD44s and isoforms containing CD44-6v, and P < 0.007 for those containing CD44-9v). Also, in chromophilic cell carcinomas (n = 13), CD44 isoform expression correlated with grading; ie, no CD44 expression was detected in G1 tumors, whereas in approximately 50% of the G2 tumors, CD44s, CD44-6v, and CD44-9v isoforms were present. Oncocytomas (n = 8), which are benign renal cell tumors, did not express CD44 isoforms, whereas invasive chromophobe cell carcinomas (n = 11) were positive for CD44s and CD44v isoforms. Transcript analyses by RT-PCR revealed that the upregulated isoforms in the carcinoma cells contained exons 8 to 10 and 3, 8 to 10 in combination from the variant region. In conclusion, expression of variant CD44 isoforms was strongly correlated with grading and appears to mediate a more aggressive phenotype to renal cell tumors. Images Figure 3 Figure 4 Figure 5 Figure 6 PMID:8579108

  5. Identification of signals that facilitate isoform specific nucleolar localization of myosin IC.

    PubMed

    Schwab, Ryan S; Ihnatovych, Ivanna; Yunus, Sharifah Z S A; Domaradzki, Tera; Hofmann, Wilma A

    2013-05-01

    Myosin IC is a single headed member of the myosin superfamily that localizes to the cytoplasm and the nucleus, where it is involved in transcription by RNA polymerases I and II, intranuclear transport, and nuclear export. In mammalian cells, three isoforms of myosin IC are expressed that differ only in the addition of short isoform-specific N-terminal peptides. Despite the high sequence homology, the isoforms show differences in cellular distribution, in localization to nuclear substructures, and in their interaction with nuclear proteins through yet unknown mechanisms. In this study, we used EGFP-fusion constructs that express truncated or mutated versions of myosin IC isoforms to detect regions that are involved in isoform-specific localization. We identified two nucleolar localization signals (NoLS). One NoLS is located in the myosin IC isoform B specific N-terminal peptide, the second NoLS is located upstream of the neck region within the head domain. We demonstrate that both NoLS are functional and necessary for nucleolar localization of specifically myosin IC isoform B. Our data provide a first mechanistic explanation for the observed functional differences between the myosin IC isoforms and are an important step toward our understanding of the underlying mechanisms that regulate the various and distinct functions of myosin IC isoforms.

  6. Biological functions of p53 isoforms through evolution: lessons from animal and cellular models.

    PubMed

    Marcel, V; Dichtel-Danjoy, M-L; Sagne, C; Hafsi, H; Ma, D; Ortiz-Cuaran, S; Olivier, M; Hall, J; Mollereau, B; Hainaut, P; Bourdon, J-C

    2011-12-01

    The TP53 tumour-suppressor gene is expressed as several protein isoforms generated by different mechanisms, including use of alternative promoters, splicing sites and translational initiation sites, that are conserved through evolution and within the TP53 homologues, TP63 and TP73. Although first described in the eighties, the importance of p53 isoforms in regulating the suppressive functions of p53 has only become evident in the last 10 years, by analogy with observations that p63 and p73 isoforms appeared indispensable to fully understand the biological functions of TP63 and TP73. This review summarizes recent advances in the field of 'p53 isoforms', including new data on p63 and p73 isoforms. Details of the alternative mechanisms that produce p53 isoforms and cis- and trans-regulators identified are provided. The main focus is on their biological functions (apoptosis, cell cycle, aging and so on) in cellular and animal models, including mouse, zebrafish and Drosophila. Finally, the deregulation of p53 isoform expression in human cancers is reviewed. Based on these latest results, several developments are expected in the future: the identification of drugs modulating p53 isoform expression; the generation of animal models and the evaluation of the use of p53 isoform as biomarkers in human cancers.

  7. Nuclear progesterone receptor isoforms and their functions in the female reproductive tract.

    PubMed

    Rekawiecki, R; Kowalik, M K; Kotwica, J

    2011-01-01

    Progesterone (P4), which is produced by the corpus luteum (CL), creates proper conditions for the embryo implantation, its development, and ensures proper conditions for the duration of pregnancy. Besides the non-genomic activity of P4 on target cells, its main physiological effect is caused through genomic action by the progesterone nuclear receptor (PGR). This nuclear progesterone receptor occurs in two specific isoforms, PGRA and PGRB. PGRA isoform acts as an inhibitor of transcriptional action of PGRB. The inactive receptor is connected with chaperone proteins and attachment of P4 causes disconnection of chaperones and unveiling of DNA binding domain (DBD). After receptor dimerization in the cells' nucleus and interaction with hormone response element (HRE), the receptor coactivators are connected and transcription is initiated. The ratio of these isoforms changes during the estrous cycle and reflects the different levels of P4 effect on the reproductive system. Both isoforms, PGRA and PGRB, also show a different response to the P4 receptor antagonist activity. Connection of the antagonist to PGRA can block PGRB, but acting through the PGRB isoform, P4 receptor antagonist may undergo conversion to a strongly receptor agonist. A third isoform, PGRC, has also been revealed. This isoform is the shortest and does not have transcriptional activity. Alternative splicing and insertion of additional exons may lead to the formation of different PGR isoforms. This paper summarizes the available data on the progesterone receptor isoforms and its regulatory action within the female reproductive system.

  8. Unravelling the different functions of protein kinase C isoforms in platelets.

    PubMed

    Heemskerk, Johan W M; Harper, Matthew T; Cosemans, Judith M E M; Poole, Alastair W

    2011-06-23

    Platelets tightly regulate haemostasis and arterial thrombosis. Protein kinase C (PKC) is involved in most platelet responses implicated in thrombus formation. Recent pharmacological and mouse gene knockout approaches show that the conventional PKC isoforms and the novel PKC isoforms contribute in distinct ways to these platelet responses. We hypothesize that, in platelets and other cells, the characteristic functions of PKC isoforms are established through unique activation mechanisms and unique interacting protein partners, which result in isoform-specific patterns of substrate phosphorylation. For identifying the substrate proteins in a living cell, new methodology is available and discussed.

  9. Multiple isoforms of β-TrCP display differential activities in the regulation of Wnt signaling

    PubMed Central

    Seo, Eunjeong; Kim, Hyunjoon; Kim, Rokki; Yun, Sangmoon; Kim, Minseong; Han, Jin-Kwan; Costantini, Frank; Jho, Eek-hoon

    2008-01-01

    The F-box proteins β-TrCP 1 and 2 (β-transducin repeat protein) have 2 and 3 isoforms, respectively, due to alternative splicing of exons encoding the N-terminal region. We identified an extra exon in between the previously known exons 1 and 2 of β-TrCP1 and β-TrCP2. Interestingly, sequence analysis suggested that many more isoforms are produced than previously identified, via the alternative splicing of all possible combination of exons II to V of β-TrCP1 and exons II to IV of β-TrCP2. Different mouse tissues show specific expression patterns of the isoforms, and the level of expression of the isoform that has been used in most published papers was very low. Yeast two-hybrid assays show that β-TrCP1 isoforms containing exon III, which are the most highly expressed isoforms in most tissues, do not interact with Skp1. Indirect immunofluorescence analysis of transiently expressed β-TrCP1 isoforms suggests that the presence of exon III causes β-TrCP1 to localize in nuclei. Consistent with the above findings, isoforms including exon III showed a reduced ability to block ectopic embryonic axes induced via injection of Wnt8 or β-catenin in Xenopus embryos. Overall, our data suggest that isoforms of β-TrCPs generated by alternative splicing may have different biological roles. PMID:18929646

  10. Analysis of segmental duplications, mouse genome synteny and recurrent cancer-associated amplicons in human chromosome 6p21-p12.

    PubMed

    Martin, J W; Yoshimoto, M; Ludkovski, O; Thorner, P S; Zielenska, M; Squire, J A; Nuin, P A S

    2010-06-01

    It has been proposed that regions of microhomology in the human genome could facilitate genomic rearrangements, copy number transitions, and rapid genomic change during tumor progression. To investigate this idea, this study examines the role of repetitive sequence elements, and corresponding syntenic mouse genomic features, in targeting cancer-associated genomic instability of specific regions of the human genome. Automated database-mining algorithms designed to search for frequent copy number transitions and genomic breakpoints were applied to 2 publicly-available online databases and revealed that 6p21-p12 is one of the regions of the human genome most frequently involved in tumor-specific alterations. In these analyses, 6p21-p12 exhibited the highest frequency of genomic amplification in osteosarcomas. Analysis of repetitive elements in regions of homology between human chromosome 6p and the syntenic regions of the mouse genome revealed a strong association between the location of segmental duplications greater than 5 kilobase-pairs and the position of discontinuities at the end of the syntenic region. The presence of clusters of segmental duplications flanking these syntenic regions also correlated with a high frequency of amplification and genomic alteration. Collectively, the experimental findings, in silico analyses, and comparative genomic studies presented here suggest that segmental duplications may facilitate cancer-associated copy number transitions and rearrangements at chromosome 6p21-p12. This process may involve homology-dependent DNA recombination and/or repair, which may also contribute towards the overall plasticity of the human genome.

  11. Dysbindin (DTNBP1, 6p22.3) is Associated with Childhood-Onset Psychosis and Endophenotypes Measured by the Premorbid Adjustment Scale (PAS)

    ERIC Educational Resources Information Center

    Gornick, M. C.; Addington, A. M.; Sporn, A.; Gogtay, N.; Greenstein, D.; Lenane, M.; Gochman, P.; Ordonez, A.; Balkissoon, R.; Vakkalanka, R.; Weinberger, D. R.; Rapoport, J. L.; Straub, R. E.

    2005-01-01

    Straub "et al." ("2002") recently identified the 6p22.3 gene dysbindin (DTNBP1) through positional cloning as a schizophrenia susceptibility gene. We studied a rare cohort of 102 children with onset of psychosis before age 13. Standardized ratings of early development, medication response, neuropsychological and cognitive performance, premorbid…

  12. Direct mapping of 19F in 19FDG-6P in brain tissue at subcellular resolution using soft X-ray fluorescence

    NASA Astrophysics Data System (ADS)

    Poitry-Yamate, C.; Gianoncelli, A.; Kourousias, G.; Kaulich, B.; Lepore, M.; Gruetter, R.; Kiskinova, M.

    2013-10-01

    Low energy x-ray fluorescence (LEXRF) detection was optimized for imaging cerebral glucose metabolism by mapping the fluorine LEXRF signal of 19F in 19FDG, trapped as intracellular 19F-deoxyglucose-6-phosphate (19FDG-6P) at 1μm spatial resolution from 3μm thick brain slices. 19FDG metabolism was evaluated in brain structures closely resembling the general cerebral cytoarchitecture following formalin fixation of brain slices and their inclusion in an epon matrix. 2-dimensional distribution maps of 19FDG-6P were placed in a cytoarchitectural and morphological context by simultaneous LEXRF mapping of N and O, and scanning transmission x-ray (STXM) imaging. A disproportionately high uptake and metabolism of glucose was found in neuropil relative to intracellular domains of the cell body of hypothalamic neurons, showing directly that neurons, like glial cells, also metabolize glucose. As 19F-deoxyglucose-6P is structurally identical to 18F-deoxyglucose-6P, LEXRF of subcellular 19F provides a link to in vivo 18FDG PET, forming a novel basis for understanding the physiological mechanisms underlying the 18FDG PET image, and the contribution of neurons and glia to the PET signal.

  13. Organometallic ruthenium complexes with thiosemicarbazone ligands: Synthesis, structure and cytotoxicity of [(η6-p-cymene)Ru(NS)Cl]+ (NS = 9-anthraldehyde thiosemicarbazones)

    PubMed Central

    Beckford, Floyd A.; Leblanc, Gabriel; Thessing, Jeffrey; Shaloski, Michael; Frost, Brian J.; Li, Liya; Seeram, Navindra P.

    2009-01-01

    A series of half-sandwich arene-ruthenium complexes of the type [(η6-p-cymene) Ru(thiosemicarbazone)Cl]+ have been synthesized and their biological activity investigated. The first structurally characterized arene-ruthenium half-sandwich complex with a thiosemicarbazone ligand is reported. PMID:20160909

  14. Erratum: Letter to the Editor: Exclusion of primary congenital glaucoma (buphthalmos) from two candidate regions of chromosome arm 6p and chromosome 11

    SciTech Connect

    1996-03-01

    This {open_quotes}Letter to the Editor{close_quotes} is the reprint of a corrected table from a previous paper about the exclusion of primary congenital glaucoma from two candidate regions of chromosome arm 6p and chromosome 11.

  15. Localization of a locus for juvenile myoclonic epilepsy on chromosome 6p11-21.2 and evidence for genetic heterogeneity

    SciTech Connect

    Liu, A.W.; Delgado-Escueta, A.V. |; Alonso, V.M.E.

    1994-09-01

    Juvenile myoclonic epilepsy (JME) is a common form of primary idiopathic generalized epilepsy characterized by myoclonias, tonic-clonic or clonic tonic-clonic convulsions and absences. Ictal electroencephalograms (EEGs) show high amplitude multispikes folowed by slow waves and interictal EEGs manifest 3.5-6 Hz diffuse multispike wave complexes. JME affected about 7-10% of patients with epilepsies and its onset peaks between 13-15 years of age. We recently mapped a JME locus on chromosome 6p21.1-6p11 by linkage analysis of one relatively large JME family from Los Angeles and Belize. Assuming autosomal dominant inheritance with 70% penetrance, pairwise analyses tightly linked JME to D6S257 (Z = 3.67), D6S428 (Z = 3.08) and D6S272 (Z = 3.56) at {theta} = 0, m = f. Recombination and multipoints linkage analysis also suggested a locus is between markers D6S257 and D6S272. We then screened three relatively larger Mexican JME pedigrees with D6S257, D6S272, D6S282, TNF, D6S276, D6S273, D6S105 and F13A1 on chromosome 6p. Assuming autosomal dominant inheritance with incomplete penetrance, linkage to chromosome 6p DNA markers are excluded. Our findings underline the genetic heterogeneity of juvenile myoclonic epilepsy.

  16. ADP-ribosylation factor arf6p may function as a molecular switch of new end take off in fission yeast

    SciTech Connect

    Fujita, Atsushi

    2008-02-01

    Small GTPases act as molecular switches in a wide variety of cellular processes. In fission yeast Schizosaccharomyces pombe, the directions of cell growth change from a monopolar manner to a bipolar manner, which is known as 'New End Take Off' (NETO). Here I report the identification of a gene, arf6{sup +}, encoding an ADP-ribosylation factor small GTPase, that may be essential for NETO. arf6{delta} cells completely fail to undergo NETO. arf6p localizes at both cell ends and presumptive septa in a cell-cycle dependent manner. And its polarized localization is not dependent on microtubules, actin cytoskeletons and some NETO factors (bud6p, for3p, tea1p, tea3p, and tea4p). Notably, overexpression of a fast GDP/GTP-cycling mutant of arf6p can advance the timing of NETO. These findings suggest that arf6p functions as a molecular switch for the activation of NETO in fission yeast.

  17. Quantification of spatiotemporal patterns of Ras isoform expression during development

    PubMed Central

    Newlaczyl, Anna U.; Coulson, Judy M.; Prior, Ian A.

    2017-01-01

    Ras proteins are important signalling hubs frequently dysregulated in cancer and in a group of developmental disorders called Rasopathies. Three Ras genes encode four proteins that differentially contribute to these phenotypes. Using quantitative real-time PCR (qRT-PCR) we have measured the gene expression profiles of each of the Ras isoforms in a panel of mouse tissues derived from a full developmental time course spanning embryogenesis through to adulthood. In most tissues and developmental stages we observe a relative contribution of KRas4B > > NRas ≥ KRas4A > HRas to total Ras expression with KRas4B typically representing 60–99% of all Ras transcripts. KRas4A is the most dynamically regulated Ras isoform with significant up-regulation of expression observed pre-term in stomach, intestine, kidney and heart. The expression patterns assist interpretation of the essential role of KRas in development and the preponderance of KRas mutations in cancer. PMID:28117393

  18. Isoform-dependent interaction of BRDG1 with Tec kinase.

    PubMed

    Yokohari, K; Yamashita, Y; Okada, S; Ohya, K; Oda, S; Hatano, M; Mano, H; Hirasawa, H; Tokuhisa, T

    2001-11-30

    Tec is the prototype of an emerging family of protein-tyrosine kinases. Tec and Btk, another member of this family, together participate in the development of B-cell immune system. We previously identified one of the downstream messengers for human Tec kinase, BRDG1. BRDG1 is associated with Tec and becomes tyrosine-phosphorylated in B-cells by the engagement of B-cell antigen receptor (BCR). Here we show that overexpression of BRDG1 strongly augments BCR-mediated activation of cAMP-response element binding protein (CREB) but not that of c-Jun and the promoters of c-MYC and BCL-xL genes. Furthermore, we isolated the murine orthologue of BRDG1. Three isoforms of BRDG1 are generated by alternative splicing of the message. Two of them have a deletion of 33 amino acids in a Pleckstrin homology (PH) domain of BRDG1. Both the tyrosine-phosphorylation and CREB-activating ability of BRDG1 were isoform-dependent, suggesting a role of the PH domain of BRDG1. These data have identified a novel regulatory mechanism of CREB family of transcriptional factors.

  19. Isoform-Specific Localization of A-RAF in Mitochondria

    PubMed Central

    Yuryev, Anton; Ono, Makoto; Goff, Stephen A.; Macaluso, Frank; Wennogle, Lawrence P.

    2000-01-01

    RAF kinase is a family of isoforms including A-RAF, B-RAF, and C-RAF. Despite the important role of RAF in cell growth and proliferation, little evidence exists for isoform-specific function of RAF family members. Using Western analysis and immunogold labeling, A-RAF was selectively localized in highly purified rat liver mitochondria. Two novel human proteins, which interact specifically with A-RAF, were identified, and the full-length sequences are reported. These proteins, referred to as hTOM and hTIM, are similar to components of mitochondrial outer and inner membrane protein-import receptors from lower organisms, implicating their involvement in the mitochondrial transport of A-RAF. hTOM contains multiple tetratricopeptide repeat (TPR) domains, which function in protein-protein interactions. TPR domains are frequently present in proteins involved in cellular transport systems. In contrast, protein 14-3-3, an abundant cytosolic protein that participates in many facets of signal transduction, was found to interact with C-RAF but not with A-RAF N-terminal domain. This information is discussed in view of the important role of mitochondria in cellular functions involving energy balance, proliferation, and apoptosis and the potential role of A-RAF in regulating these systems. PMID:10848612

  20. Role of cysteines in mammalian VDAC isoforms' function.

    PubMed

    De Pinto, Vito; Reina, Simona; Gupta, Ankit; Messina, Angela; Mahalakshmi, Radhakrishnan

    2016-08-01

    In this mini-review, we analyze the influence of cysteines in the structure and activity of mitochondrial outer membrane mammalian VDAC isoforms. The three VDAC isoforms show conserved sequences, similar structures and the same gene organization. The meaning of three proteins encoded in different chromosomes must thus be searched for subtle differences at the amino acid level. Among others, cysteine content is noticeable. In humans, VDAC1 has 2, VDAC2 has 9 and VDAC3 has 6 cysteines. Recent works have shown that, at variance from VDAC1, VDAC2 and VDAC3 exhibit cysteines predicted to protrude towards the intermembrane space, making them a preferred target for oxidation by ROS. Mass spectrometry in VDAC3 revealed that a disulfide bridge can be formed and other cysteine oxidations are also detectable. Both VDAC2 and VDAC3 cysteines were mutagenized to highlight their role in vitro and in complementation assays in Δporin1 yeast. Chemico-physical techniques revealed an important function of cysteines in the structural stabilization of the pore. In conclusion, the works available on VDAC cysteines support the notion that the three proteins are paralogs with a similar pore-function and slightly different, but important, ancillary biological functions. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi.

  1. Tau Isoform Composition Influences Rate and Extent of Filament Formation*

    PubMed Central

    Zhong, Qi; Congdon, Erin E.; Nagaraja, Haikady N.; Kuret, Jeff

    2012-01-01

    The risk of developing tauopathic neurodegenerative disease depends in part on the levels and composition of six naturally occurring Tau isoforms in human brain. These proteins, which form filamentous aggregates in disease, vary only by the presence or absence of three inserts encoded by alternatively spliced exons 2, 3, and 10 of the Tau gene (MAPT). To determine the contribution of alternatively spliced segments to Tau aggregation propensity, the aggregation kinetics of six unmodified, recombinant human Tau isoforms were examined in vitro using electron microscopy assay methods. Aggregation propensity was then compared at the level of elementary rate constants for nucleation and extension phases. We found that all three alternatively spliced segments modulated Tau aggregation but through differing kinetic mechanisms that could synergize or compete depending on sequence context. Overall, segments encoded by exons 2 and 10 promoted aggregation, whereas the segment encoded by exon 3 depressed it with its efficacy dependent on the presence or absence of a fourth microtubule binding repeat. In general, aggregation propensity correlated with genetic risk reported for multiple tauopathies, implicating aggregation as one candidate mechanism rationalizing the correlation between Tau expression patterns and disease. PMID:22539343

  2. Autocrine Signaling Underlies Fast Repetitive Plasma Membrane Translocation of Conventional and Novel Protein Kinase C Isoforms in β Cells*

    PubMed Central

    Wuttke, Anne; Yu, Qian; Tengholm, Anders

    2016-01-01

    PKC signaling has been implicated in the regulation of many cell functions, including metabolism, cell death, proliferation, and secretion. Activation of conventional and novel PKC isoforms is associated with their Ca2+- and/or diacylglycerol (DAG)-dependent translocation to the plasma membrane. In β cells, exocytosis of insulin granules evokes brief (<10 s) local DAG elevations (“spiking”) at the plasma membrane because of autocrine activation of P2Y1 purinoceptors by ATP co-released with insulin. Using total internal reflection microscopy, fluorescent protein-tagged PKCs, and signaling biosensors, we investigated whether DAG spiking causes membrane recruitment of PKCs and whether different classes of PKCs show characteristic responses. Glucose stimulation of MIN6 cells triggered DAG spiking with concomitant repetitive translocation of the novel isoforms PKCδ, PKCϵ, and PKCη. The conventional PKCα, PKCβI, and PKCβII isoforms showed a more complex pattern with both rapid and slow translocation. K+ depolarization-induced PKCϵ translocation entirely mirrored DAG spiking, whereas PKCβI translocation showed a sustained component, reflecting the subplasma membrane Ca2+ concentration ([Ca2+]pm), with additional effect during DAG spikes. Interference with DAG spiking by purinoceptor inhibition prevented intermittent translocation of PKCs and reduced insulin secretion but did not affect [Ca2+]pm elevation or sustained PKCβI translocation. The muscarinic agonist carbachol induced pronounced transient PKCβI translocation and sustained recruitment of PKCϵ. When rise of [Ca2+]pm was prevented, the carbachol-induced DAG and PKCϵ responses were somewhat reduced, but PKCβI translocation was completely abolished. We conclude that exocytosis-induced DAG spikes efficiently recruit both conventional and novel PKCs to the β cell plasma membrane. PKC signaling is thus implicated in autocrine regulation of β cell function. PMID:27226533

  3. Digoxin derivatives with selectivity for the α2β3 isoform of Na,K-ATPase potently reduce intraocular pressure

    PubMed Central

    Katz, Adriana; Tal, Daniel M.; Heller, Dan; Habeck, Michael; Ben Zeev, Efrat; Rabah, Bilal; Bar Kana, Yaniv; Marcovich, Arie L.; Karlish, Steven J. D.

    2015-01-01

    The ciliary epithelium in the eye consists of pigmented epithelial cells that express the α1β1 isoform of Na,K-ATPase and nonpigmented epithelial cells that express mainly the α2β3 isoform. In principle, a Na,K-ATPase inhibitor with selectivity for α2β3 that penetrates the cornea could effectively reduce intraocular pressure, with minimal systemic or local toxicity. We have recently synthesized perhydro-1,4-oxazepine derivatives of digoxin by NaIO4 oxidation of the third digitoxose and reductive amination with various R-NH2 substituents and identified derivatives with significant selectivity for human α2β1 over α1β1 (up to 7.5-fold). When applied topically, the most α2-selective derivatives effectively prevented or reversed pharmacologically raised intraocular pressure in rabbits. A recent structure of Na,K-ATPase, with bound digoxin, shows the third digitoxose approaching one residue in the β1 subunit, Gln84, suggesting a role for β in digoxin binding. Gln84 in β1 is replaced by Val88 in β3. Assuming that alkyl substituents might interact with β3Val88, we synthesized perhydro-1,4-oxazepine derivatives of digoxin with diverse alkyl substituents. The methylcyclopropyl and cyclobutyl derivatives are strongly selective for α2β3 over α1β1 (22–33-fold respectively), as determined either with purified human isoform proteins or intact bovine nonpigmented epithelium cells. When applied topically on rabbit eyes, these derivatives potently reduce both pharmacologically raised and basal intraocular pressure. The cyclobutyl derivative is more efficient than Latanoprost, the most widely used glaucoma drug. Thus, the conclusion is that α2β3-selective digoxin derivatives effectively penetrate the cornea and inhibit the Na,K-ATPase, hence reducing aqueous humor production. The new digoxin derivatives may have potential for glaucoma drug therapy. PMID:26483500

  4. Glutamate dehydrogenase isoforms with N-terminal (His)6- or FLAG-tag retain their kinetic properties and cellular localization.

    PubMed

    Pajęcka, Kamilla; Nielsen, Camilla Wendel; Hauge, Anne; Zaganas, Ioannis; Bak, Lasse K; Schousboe, Arne; Plaitakis, Andreas; Waagepetersen, Helle S

    2014-01-01

    Glutamate dehydrogenase (GDH) is a crucial enzyme on the crossroads of amino acid and energy metabolism and it is operating in all domains of life. According to current knowledge GDH is present only in one functional isoform in most animals, including mice. In addition to this housekeeping enzyme (hGDH1 in humans), humans and apes have acquired a second isoform (hGDH2) with a distinct tissue expression profile. In the current study we have cloned both mouse and human GDH constructs containing FLAG and (His)6 small genetically-encoded tags, respectively. The hGDH1 and hGDH2 constructs containing N-terminal (His)6 tags were successfully expressed in Sf9 cells and the recombinant proteins were isolated to ≥95 % purity in a two-step procedure involving ammonium sulfate precipitation and Ni(2+)-based immobilized metal ion affinity chromatography. To explore whether the presence of the FLAG and (His)6 tags affects the cellular localization and functionality of the GDH isoforms, we studied the subcellular distribution of the expressed enzymes as well as their regulation by adenosine diphosphate monopotassium salt (ADP) and guanosine-5'-triphosphate sodium salt (GTP). Through immunoblot analysis of the mitochondrial and cytosolic fraction of the HEK cells expressing the recombinant proteins we found that neither FLAG nor (His)6 tag disturbs the mitochondrial localization of GDH. The addition of the small tags to the N-terminus of the mature mitochondrial mouse GDH1 or human hGDH1 and hGDH2 did not change the ADP activation or GTP inhibition pattern of the proteins as compared to their untagged counterparts. However, the addition of FLAG tag to the C-terminus of the mouse GDH left the recombinant protein fivefold less sensitive to ADP activation. This finding highlights the necessity of the functional characterization of recombinant proteins containing even the smallest available tags.

  5. Digoxin derivatives with selectivity for the α2β3 isoform of Na,K-ATPase potently reduce intraocular pressure.

    PubMed

    Katz, Adriana; Tal, Daniel M; Heller, Dan; Habeck, Michael; Ben Zeev, Efrat; Rabah, Bilal; Bar Kana, Yaniv; Marcovich, Arie L; Karlish, Steven J D

    2015-11-03

    The ciliary epithelium in the eye consists of pigmented epithelial cells that express the α1β1 isoform of Na,K-ATPase and nonpigmented epithelial cells that express mainly the α2β3 isoform. In principle, a Na,K-ATPase inhibitor with selectivity for α2β3 that penetrates the cornea could effectively reduce intraocular pressure, with minimal systemic or local toxicity. We have recently synthesized perhydro-1,4-oxazepine derivatives of digoxin by NaIO4 oxidation of the third digitoxose and reductive amination with various R-NH2 substituents and identified derivatives with significant selectivity for human α2β1 over α1β1 (up to 7.5-fold). When applied topically, the most α2-selective derivatives effectively prevented or reversed pharmacologically raised intraocular pressure in rabbits. A recent structure of Na,K-ATPase, with bound digoxin, shows the third digitoxose approaching one residue in the β1 subunit, Gln84, suggesting a role for β in digoxin binding. Gln84 in β1 is replaced by Val88 in β3. Assuming that alkyl substituents might interact with β3Val88, we synthesized perhydro-1,4-oxazepine derivatives of digoxin with diverse alkyl substituents. The methylcyclopropyl and cyclobutyl derivatives are strongly selective for α2β3 over α1β1 (22-33-fold respectively), as determined either with purified human isoform proteins or intact bovine nonpigmented epithelium cells. When applied topically on rabbit eyes, these derivatives potently reduce both pharmacologically raised and basal intraocular pressure. The cyclobutyl derivative is more efficient than Latanoprost, the most widely used glaucoma drug. Thus, the conclusion is that α2β3-selective digoxin derivatives effectively penetrate the cornea and inhibit the Na,K-ATPase, hence reducing aqueous humor production. The new digoxin derivatives may have potential for glaucoma drug therapy.

  6. Identification of the human UDP-glucuronosyltransferase isoforms involved in the glucuronidation of the phytochemical ferulic acid.

    PubMed

    Li, Xiaojun; Shang, Liang; Wu, Yaohua; Abbas, Suzanne; Li, Dong; Netter, Patrick; Ouzzine, Mohamed; Wang, Hui; Magdalou, Jacques

    2011-01-01

    Ferulic acid (FA), a member of the hydroxycinnamate family, is an abundant dietary antioxidant that may offer beneficial effects against cancer, cardiovascular disease, diabetes, osteoarthritis and Alzheimer's disease. In this study, evidence for sulfation and glucuronidation of FA was investigated upon incubation with human liver microsomes and cytosol. Two main glucuronides, M1 (ether O-glucuronide) and M2 (ester acylglucuronide), were formed with a similar affinity (apparent K(m) 3.53 and 5.15 mM, respectively). A phenol sulfoconjugate was also formed with a higher affinity (K(m) 0.53 mM). Identification of the UDP-glucuronosyltransferase (UGT) isoforms involved in FA glucuronidation was investigated with 12 human recombinant enzymes. FA was mainly glucuronidated by UGT1A isoforms and by UGT2B7. UGT1A4, 2B4, 2B15 and 2B17 failed to glucuronidate the substance. Examination of the kinetic constants revealed that FA was mainly glucuronidated by UGT1A1 at the two nucleophilic groups. UGT1A3 was able to glucuronidate these two positions with the same, but low, efficiency. UGT1A6 and 1A8 were involved in the formation of the ether glucuronide only, whereas UGT1A7, 1A10 and 2B7 preferentially glucuronidated the carboxyl group. Moreover, octyl gallate, a marker substrate of UGT1A1, competitively inhibited FA glucuronidation mediated by this isoform. Altogether, the results suggest that FA glucuronidation is primarily mediated by UGT1A1.

  7. PI3Kɑ inhibition reduces obesity in mice

    PubMed Central

    Lopez-Guadamillas, Elena; Muñoz-Martin, Maribel; Martinez, Sonia; Pastor, Joaquin; Fernandez-Marcos, Pablo J.; Serrano, Manuel

    2016-01-01

    Partial inhibition of PI3K is one of the best-validated and evolutionary conserved manipulations to extend longevity. The best known health beneficial effects of reduced PI3K are related to metabolism and include increased energy expenditure, reduced nutrient storage, and protection from obesity. We have previously shown that a dual chemical inhibitor of the alpha and delta PI3K isoforms (CNIO-PI3Ki) reduces obesity in mice and monkeys, without evident toxic effects after long-term treatment. Here, we dissect the role of the alpha and delta PI3K isoforms by making use of selective inhibitors against PI3Kɑ (BYL-719 also known as alpelisib) or PI3Kδ (GS-9820 also known as acalisib). Treatment of mice with the above mentioned inhibitors indicated that BYL-719 increases energy expenditure in normal mice and efficiently reduces body weight in obese (ob/ob) mice, whereas these effects were not observed with GS-9820. Of note, the dose of BYL-719 required to reduce obesity was 10-times higher than the equivalent dose of CNIO-PI3Ki, which could suggest that simultaneous inhibition of PI3K alpha and delta is more beneficial than single inhibition of the alpha isoform. In summary, we conclude that inhibition of PI3Kɑ is sufficient to increase energy expenditure and reduce obesity, and suggest that concomitant PI3Kδ inhibition could play an auxiliary role. PMID:27816049

  8. Differential expression of trehalose 6-P phosphatase and ascorbate peroxidase transcripts in nodule cortex of Phaseolus vulgaris and regulation of nodule O2 permeability.

    PubMed

    Bargaz, Adnane; Lazali, Mohamed; Amenc, Laurie; Abadie, Josiane; Ghoulam, Cherki; Farissi, Mohamed; Faghire, Mustapha; Drevon, Jean-Jacques

    2013-07-01

    Although the role of phosphatases and antioxidant enzymes have been documented in phosphorus (P) deficiency tolerance, gene expression differences in the nodules of nitrogen fixing legumes should also affect tolerance to this soil constraint. In this study, root nodules were induced by Rhizobium tropici CIAT899 in two Phaseolus vulgaris recombinant inbred lines (RIL); RIL115 (low P-tolerant) and RIL147 (low P-sensitive) under hydroaeroponic culture with sufficient versus deficient P supply. Trehalose 6-P phosphatase and ascorbate peroxidase transcripts were localized within nodules in which O2 permeability was measured. Results indicate that differential tissues-specific expression of trehalose 6-P phosphatase and ascorbate peroxidase transcripts within nodules was detected particularly in infected zone and cortical cells. Under P-deficiency, trehalose 6-P phosphatase transcript was increased and mainly localized in infected zone and outer cortex of RIL115 as compared to RIL147. Ascorbate peroxidase transcript was highly expressed under P-sufficiency in the infected zone, inner cortex and vascular traces of RIL115 rather than RIL147. In addition, significant correlations were found between nodule O2 permeability and both peroxidase (r = 0.66*) and trehalose 6-P phosphatase enzyme activities (r = 0.79*) under sufficient and deficient P conditions, respectively. The present findings suggest that the tissue-specific localized trehalose 6-P phosphatase and ascorbate peroxidase transcripts of infected cells and nodule cortex are involved in nitrogen fixation efficiency and are likely to play a role in nodule respiration and adaptation to P-deficiency.

  9. Human bronchial smooth muscle cells express adenylyl cyclase isoforms 2, 4, and 6 in distinct membrane microdomains.

    PubMed

    Bogard, Amy S; Xu, Congfeng; Ostrom, Rennolds S

    2011-04-01

    Adenylyl cyclases (AC) are important regulators of airway smooth muscle function, because β-adrenergic receptor (AR) agonists stimulate AC activity and increase airway diameter. We assessed expression of AC isoforms in human bronchial smooth muscle cells (hBSMC). Reverse transcriptase-polymerase chain reaction and immunoblot analyses detected expression of AC2, AC4, and AC6. Forskolin-stimulated AC activity in membranes from hBSMC displayed Ca(2+)-inhibited and G(βγ)-stimulated AC activity, consistent with expression of AC6, AC2, and AC4. Isoproterenol-stimulated AC activity was inhibited by Ca(2+) but unaltered by G(βγ), whereas butaprost-stimulated AC activity was stimulated by G(βγ) but unaffected by Ca(2+) addition. Using sucrose density centrifugation to isolate lipid raft fractions, we found that only AC6 localized in lipid raft fractions, whereas AC2 and AC4 localized in nonraft fractions. Immunoisolation of caveolae using caveolin-1 antibodies yielded Ca(2+)-inhibited AC activity (consistent with AC6 expression), whereas the nonprecipitated material displayed G(βγ)-stimulated AC activity (consistent with expression of AC2 and/or AC4). Overexpression of AC6 enhanced cAMP production in response to isoproterenol and beraprost but did not increase responses to prostaglandin E(2) or butaprost. β(2)AR, but not prostanoid EP(2) or EP(4) receptors, colocalized with AC5/6 in lipid raft fractions. Thus, particular G protein-coupled receptors couple to discreet AC isoforms based, in part, on their colocalization in membrane microdomains. These different cAMP signaling compartments in airway smooth muscle cells are responsive to different hormones and neurotransmitters and can be regulated by different coincident signals such as Ca(2+) and G(βγ).

  10. Identification of human cytochrome P450 isoforms involved in the 7-hydroxylation of chlorpromazine by human liver microsomes.

    PubMed

    Yoshii, K; Kobayashi, K; Tsumuji, M; Tani, M; Shimada, N; Chiba, K

    2000-01-01

    Studies to identify the cytochrome P450 (CYP) isoform(s) involved in chlorpromazine 7-hydroxylation were performed using human liver microsomes and cDNA-expressed human CYPs. The kinetics of chlorpromazine 7-hydroxylation in human liver microsomes showed a simple Michaelis-Menten behavior. The apparent Km and Vmax values were 3.4+/-1.0 microM and 200.5+/-83.7 pmol/min/mg, respectively. The chlorpromazine 7-hydroxylase activity in human liver microsomes showed good correlations with desipramine 2-hydroxylase activity (r = 0.763, p < 0.05), a marker activity for CYP2D6, and phenacetin O-deethylase activity (r = 0.638, p < 0.05), a marker activity for CYP1A2. Quinidine (an inhibitor of CYP2D6) completely inhibited while alpha-naphthoflavone (an inhibitor of CYP1A2) marginally inhibited the chlorpromazine 7-hydroxylase activity in a human liver microsomal sample showing high CYP2D6 activity. On the other hand, alpha-naphthoflavone inhibited the chlorpromazine 7-hydroxylase activity to 55-65% of control in a human liver microsomal sample showing low CYP2D6 activity. Among eleven cDNA-expressed CYPs studied, CYP2D6 and CYP1A2 exhibited significant activity for the chlorpromazine 7-hydroxylation. The Km values for the chlorpromazine 7-hydroxylation of both cDNA-expressed CYP2D6 and CYP1A2 were in agreement with the Km values of human liver microsomes. These results suggest that chlorpromazine 7-hydroxylation is catalyzed mainly by CYP2D6 and partially by CYP1A2.

  11. TRIMe7-CypA, an alternative splicing isoform of TRIMCyp in rhesus macaque, negatively modulates TRIM5α activity

    SciTech Connect

    Na, Lei; Tang, Yan-Dong; Liu, Jian-Dong; Yu, Chang-Qing; Sun, Liu-Ke; Lin, Yue-Zhi; Wang, Xue-Feng; Wang, Xiaojun; Zhou, Jian-Hua

    2014-04-04

    Highlights: • TRIMe7-CypA expresses in rhesus and pig-tailed, but not long-tailed macaques. • TRIMe7-CypA does not show the restriction to a HIV-GFP report virus in vitro. • It acts as a negative modulator to TRIM5α likely by competitive inhibition. - Abstract: The existence of innate, host-specific restriction factors is a major obstacle to the development of nonhuman primate models for AIDS studies, and TRIM5α is one of the most important of these restriction factors. In recent years, a TRIM5 chimeric gene that was retrotransposed by a cyclophilin A (CypA) cDNA was identified in certain macaque species. The TRIM5α-CypA fusion protein, TRIMCyp, which was expressed in these monkeys, had lost its restriction ability toward HIV-1. We previously found that TRIMe7-CypA, an alternative splicing isoform of the TRIMCyp transcripts, was expressed in pig-tailed and rhesus macaques but absent in long-tailed macaques. In this study, the anti-HIV-1 activity of TRIMe7-CypA in the rhesus macaque (RhTRIMe7-CypA) was investigated. The over-expression of RhTRIMe7-CypA in CrFK, HeLa and HEK293T cells did not restrict the infection or replication of an HIV-1-GFP reporter virus in these cells. As a positive control, rhesus (rh)TRIM5α strongly inhibited the reporter virus. Intriguingly, the anti-HIV-1 activity of RhTRIM5α was significantly reduced in a dose-dependent manner by the co-repression of RhTRIMe7-CypA. Our data indicate that although the RhTRIMe7-CypA isoform does not appear to restrict HIV-1, it may act as a negative modulator of TRIM family proteins, presumably by competitive inhibition.

  12. Mammotroph autoregulation: the differential roles of the 24K isoforms of prolactin.

    PubMed

    Ho, T W; Greenan, J R; Walker, A M

    1989-03-01

    In this study we have attempted to determine which of the secreted 24K isoforms was responsible for autocrine regulation of PRL secretion by comparing the isoforms synthesized and secreted by normal cells, which do autoregulate, with those synthesized and secreted by GH3 cells, which do not normally autoregulate. Comparable numbers of cells were washed free of serum and then extracted into Tris-buffered saline by sonication and detergent treatment. Proteins present in these cell extracts and in samples of culture medium were then precipitated with cold acetone (-20 C; 48 h) and subsequently dissolved in urea-lysis buffer for 2-dimensional (2-D) electrophoresis. The 2-D patterns for normal cells showed four 24K PRL isoforms inside the cells and three 24K PRL isoforms (designated 2, 3, and 3') secreted into the medium. The 2-D patterns for GH3 cells showed very little intracellular storage of PRL, but what was present was identified as 24K PRL isoform 2. The GH3 cells secreted large amounts of only 24K PRL isoform 2. Preparations of PRL containing only isoforms 1,2, and 3 (at a total radioimmunoassayable concentration of 5 micrograms/ml PRL) were capable of inducing autoregulation in GH3 cells, as evidence by decreased secretion of prelabeled intracellular PRL. Initiation of autoregulation in GH3 cells caused granulation and the intracellular production of isoform 3. Since a) a preparation containing isoforms 1, 2, and 3 was found to induce autoregulation in GH3 cells, b) isoform 1 is not a secreted form, and c) isoform 2 does not cause autoregulation (at least in GH3 cells), it is deduced that isoform 3 is an autocrine form of PRL. Since initiation of autoregulation in GH3 cells caused those cells to produce isoform 3, it is further deduced that the autoregulatory defect in GH3 cells lies in the actual lack of production of isoform 3 and not in an inherent inability of these cells to produce isoform 3.

  13. Expression of Phosphoinositide-Specific Phospholipase C Isoforms in Native Endothelial Cells

    PubMed Central

    Béziau, Delphine M.; Toussaint, Fanny; Blanchette, Alexandre; Dayeh, Nour R.; Charbel, Chimène; Tardif, Jean-Claude; Dupuis, Jocelyn; Ledoux, Jonathan

    2015-01-01

    Phospholipase C (PLC) comprises a superfamily of enzymes that play a key role in a wide array of intracellular signalling pathways, including protein kinase C and intracellular calcium. Thirteen different mammalian PLC isoforms have been identified and classified into 6 families (PLC-β, γ, δ, ε, ζ and η) based on their biochemical properties. Although the expression of PLC isoforms is tissue-specific, concomitant expression of different PLC has been reported, suggesting that PLC family is involved in multiple cellular functions. Despite their critical role, the PLC isoforms expressed in native endothelial cells (ECs) remains undetermined. A conventional PCR approach was initially used to elucidate the mRNA expression pattern of PLC isoforms in 3 distinct murine vascular beds: mesenteric (MA), pulmonary (PA) and middle cerebral arteries (MCA). mRNA encoding for most PLC isoforms was detected in MA, MCA and PA with the exception of η2 and β2 (only expressed in PA), δ4 (only expressed in MCA), η1 (expressed in all but MA) and ζ (not detected in any vascular beds tested). The endothelial-specific PLC expression was then sought in freshly isolated ECs. Interestingly, the PLC expression profile appears to differ across the investigated arterial beds. While mRNA for 8 of the 13 PLC isoforms was detected in ECs from MA, two additional PLC isoforms were detected in ECs from PA and MCA. Co-expression of multiple PLC isoforms in ECs suggests an elaborate network of signalling pathways: PLC isoforms may contribute to the complexity or diversity of signalling by their selective localization in cellular microdomains. However in situ immunofluorescence revealed a homogeneous distribution for all PLC isoforms probed (β3, γ2 and δ1) in intact endothelium. Although PLC isoforms play a crucial role in endothelial signal transduction, subcellular localization alone does not appear to be sufficient to determine the role of PLC in the signalling microdomains found in the

  14. Two temporally synthesized charge subunits interact to form the five isoforms of cottonseed (Gossypium hirsutum) catalase.

    PubMed Central

    Ni, W; Trelease, R N; Eising, R

    1990-01-01

    Five charge isoforms of tetrameric catalase were isolated from cotyledons of germinated cotton (Gossypium hirsutum L.) seedlings. Denaturing isoelectric focusing of the individual isoforms in polyacrylamide gels indicated that isoforms A (most anodic) and E (most cathodic) consisted of one subunit of different charge, whereas isoforms B, C and D each consisted of a mixture of these two subunits. Thus the five isoforms apparently were formed through combinations of two subunits in different ratios. Labelling cotyledons in vivo with [35S]methionine at three daily intervals in the dark, and translation in vivo of polyadenylated RNA isolated from cotyledons at the same ages, revealed synthesis of two different subunits. One of the subunits was synthesized in cotyledons at all ages studied (days 1-3), whereas the other subunit was detected only at days 2 and 3. This differential expression of two catalase subunits helped explain previous results from this laboratory showing that the two anodic forms (A and B) found in maturing seeds were supplemented with three cathodic forms (C-E) after the seeds germinated. These subunit data also helped clarify our new findings that proteins of isoforms A, B and C (most active isoforms) accumulated in cotyledons of plants kept in the dark for 3 days, then gradually disappeared during the next several days, whereas isoforms D and E (least active isoforms) remained in the cells. This shift in isoform pattern occurred whether seedlings were kept in the dark or exposed to continuous light after day 3, although exposure to light enhanced this process. These sequential molecular events were responsible for the characteristic developmental changes (rise and fall) in total catalase activity. We believe that the isoform changeover is physiologically related to the changeover in glyoxysome to leaf-type-peroxisome metabolism. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. PMID:1695843

  15. Altered DNA Binding and Amplification of Human Breast Cancer Suppressor Gene BRCA1 Induced by a Novel Antitumor Compound, [Ru(η6-p-phenylethacrynate)Cl2(pta)

    PubMed Central

    Chakree, Korawan; Ovatlarnporn, Chitchamai; Dyson, Paul J.; Ratanaphan, Adisorn

    2012-01-01

    The ruthenium-based complex [Ru(η6-p-phenylethacrynate)Cl2(pta)] (pta = 1,3,5-triaza-7-phosphatricyclo-[3.3.1.1]decane), termed ethaRAPTA, is an interesting antitumor compound. The elucidation of the molecular mechanism of drug activity is central to the drug development program. To this end, we have characterized the ethaRAPTA interaction with DNA, including probing the sequence specific modified DNA structural stability and DNA amplification using the breast cancer suppressor gene 1 (BRCA1) of human breast and colon adenocarcinoma cell lines as models. The preference of ethaRAPTA base binding is in the order A > G > T > C. Once modified, the ethaRAPTA-induced BRCA1 structure has higher thermal stability than the modified equivalents of its related compound, RAPTA-C. EthaRAPTA exhibits a higher efficiency than RAPTA-C in inhibiting BRCA1 amplification. With respect to both compounds, the inhibition of BRCA1 amplification is more effective in an isolated system than in cell lines. These data provide evidence that will help to understand the process of elucidating the pathways involved in the response induced by ethaRAPTA. PMID:23202946

  16. Isoform-specific toxicity of Mecp2 in postmitotic neurons: Suppression of neurotoxicity by FoxG1

    PubMed Central

    Dastidar, Somasish Ghosh; Bardai, Farah H.; Ma, Chi; Price, Valerie; Rawat, Varun; Verma, Pragya; Narayanan, Vinodh; D’Mello, Santosh R.

    2012-01-01

    The methyl-CpG Binding Protein 2 (MeCP2) is a widely expressed protein, mutations of which cause Rett syndrome. The level of MeCP2 is highest in the brain where it is expressed selectively in mature neurons. Its functions in postmitotic neurons are not known. The MeCP2 gene is alternatively-spliced to generate two proteins with different N-termini, designated as MeCP2-e1 and MeCP2-e2. The physiological significance of these two isoforms has not been elucidated and it is generally assumed they are functionally equivalent. We report that in cultured cerebellar granule neurons induced to die by low potassium treatment and in Aβ-treated cortical neurons, Mecp2-e2 expression is upregulated whereas expression of the Mecp2-e1 isoform is downregulated. Knockdown of Mecp2-e2 protects neurons from death whereas knockdown of the e1 isoform has no effect. Forced expression of MeCP2-e2, but not MeCP2-e1, promotes apoptosis in otherwise healthy neurons. We find that MeCP2-e2 interacts with the forkhead protein FoxG1, mutations of which also cause Rett syndrome. FoxG1 has been shown to promote neuronal survival and its downregulation leads to neuronal death. We find that elevated FoxG1 expression inhibits MeCP2-e2 neurotoxicity. MeCP2-e2 neurotoxicity is also inhibited by IGF-1, which prevents the neuronal death-associated downregulation of FoxG1 expression, and by Akt, activation of which is necessary for FoxG1-mediated neuroprotection. Finally, MeCP2-e2 neurotoxicity is enhanced if FoxG1 expression is suppressed or in neurons cultured from FoxG1-haplodeficient mice. Our results indicate that Mecp2-e2 promotes neuronal death and that this activity is normally inhibited by FoxG1. Reduced FoxG1expression frees Mecp2-e2 to promote neuronal death. PMID:22357867

  17. Structure of 'linkerless' hydroxamic acid inhibitor-HDAC8 complex confirms the formation of an isoform-specific subpocket.

    PubMed

    Tabackman, Alexa A; Frankson, Rochelle; Marsan, Eric S; Perry, Kay; Cole, Kathryn E

    2016-09-01

    Histone deacetylases (HDACs) catalyze the hydrolysis of acetylated lysine side chains in histone and non-histone proteins, and play a critical role in the regulation of many biological processes, including cell differentiation, proliferation, senescence, and apoptosis. Aberrant HDAC activity is associated with cancer, making these enzymes important targets for drug design. In general, HDAC inhibitors (HDACi) block the proliferation of tumor cells by inducing cell differentiation, cell cycle arrest, and/or apoptosis, and comprise some of the leading therapies in cancer treatments. To date, four HDACi have been FDA approved for the treatment of cancers: suberoylanilide hydroxamic acid (SAHA, Vorinostat, Zolinza®), romidepsin (FK228, Istodax®), belinostat (Beleodaq®), and panobinostat (Farydak®). Most current inhibitors are pan-HDACi, and non-selectively target a number of HDAC isoforms. Six previously reported HDACi were rationally designed, however, to target a unique sub-pocket found only in HDAC8. While these inhibitors were indeed potent against HDAC8, and even demonstrated specificity for HDAC8 over HDACs 1 and 6, there were no structural data to confirm the mode of binding. Here we report the X-ray crystal structure of Compound 6 complexed with HDAC8 to 1.98Å resolution. We also describe the use of molecular docking studies to explore the binding interactions of the other 5 related HDACi. Our studies confirm that the HDACi induce the formation of and bind in the HDAC8-specific subpocket, offering insights into isoform-specific inhibition.

  18. Role for the thromboxane A2 receptor β-isoform in the pathogenesis of intrauterine growth restriction

    PubMed Central

    Powell, Katie L.; Stevens, Veronica; Upton, Dannielle H.; McCracken, Sharon A.; Simpson, Ann M.; Cheng, Yan; Tasevski, Vitomir; Morris, Jonathan M.; Ashton, Anthony W.

    2016-01-01

    Intrauterine growth restriction (IUGR) is a pathology of pregnancy that results in failure of the fetus to reach its genetically determined growth potential. In developed nations the most common cause of IUGR is impaired placentation resulting from poor trophoblast function, which reduces blood flow to the fetoplacental unit, promotes hypoxia and enhances production of bioactive lipids (TXA2 and isoprostanes) which act through the thromboxane receptor (TP). TP activation has been implicated as a pathogenic factor in pregnancy complications, including IUGR; however, the role of TP isoforms during pregnancy is poorly defined. We have determined that expression of the human-specific isoform of TP (TPβ) is increased in placentae from IUGR pregnancies, compared to healthy pregnancies. Overexpression of TPα enhanced trophoblast proliferation and syncytialisation. Conversely, TPβ attenuated these functions and inhibited migration. Expression of the TPβ transgene in mice resulted in growth restricted pups and placentae with poor syncytialisation and diminished growth characteristics. Together our data indicate that expression of TPα mediates normal placentation; however, TPβ impairs placentation, and promotes the development of IUGR, and represents an underappreciated pathogenic factor in humans. PMID:27363493

  19. Expression of metallothoinein isoform 3 is restricted at the post-transcriptional level in human bladder epithelial cells.

    PubMed

    Garrett, Scott H; Park, Seongmi; Sens, Mary Ann; Somji, Seema; Singh, Rajendra K; Namburi, Venugopal B R K; Sens, Donald A

    2005-09-01

    This study was designed to define the effect that overexpression of MT-3 would have on a cell culture model of bladder urothelium. Stable and inducible transfection was used to achieve overexpression of the MT-3 gene in the UROtsa cell line. When the UROtsa cells were stably transfected with the MT-3 coding sequence, there was highly elevated expression of MT-3 mRNA, but no MT-3 protein. An inducible vector showed that low basal levels of MT-3 mRNA and protein could be produced, but that induction only increased MT-3 mRNA and not protein. The clones expressing low basal levels of MT-3 protein also had reduced growth rates compared to control cells. Site directed mutagenesis was used to produce an MT-3 coding sequence where the prolines in positions 7 and 9 were converted to threonines. When this altered MT-3 was stably transfected into the UROtsa cells, the cells were able to accumulate the mutated form of the MT-3 protein. These studies show that MT-3 protein expression is inhibited by post-transcriptional control in the urothelial cell. Modifying the MT-3 protein to resemble the MT-1 isoform removes this component of post-transcriptional control and allows accumulation of the mutated MT-3 protein. The altered sequence involved in post-transcriptional control of MT-3 protein expression is the same sequence implicated in the neuronal growth inhibitory activity associated specifically with the MT-3 isoform of the MT gene family.

  20. Melanoma cells produce multiple laminin isoforms and strongly migrate on α5 laminin(s) via several integrin receptors.

    PubMed

    Oikawa, Yuko; Hansson, Johan; Sasaki, Takako; Rousselle, Patricia; Domogatskaya, Anna; Rodin, Sergey; Tryggvason, Karl; Patarroyo, Manuel

    2011-05-01

    Melanoma cells express and interact with laminins (LMs) and other basement membrane components during invasion and metastasis. In the present study we have investigated the production and migration-promoting activity of laminin isoforms in melanoma. Immunohistochemistry of melanoma specimens and immunoprecipitation/western blotting of melanoma cell lines indicated expression of laminin-111/121, laminin-211, laminin-411/421, and laminin-511/521. Laminin-332 was not detected. In functional assays, laminin-111, laminin-332, and laminin-511, but not laminin-211 and laminin-411, strongly promoted haptotactic cell migration either constitutively or following stimulation with insulin-like growth factors. Both placenta and recombinant laminin-511 preparations were highly active, and the isolated recombinant IVa domain of LMα5 also promoted cell migration. Function-blocking antibodies in cell migration assays revealed α6β1 integrin as the major receptor for laminin-111, and both α3β1 and α6β1 integrins for laminin-332 and laminin-511. In contrast, isolated LMα5 IVa domain-promoted melanoma cell migration was largely mediated via αVβ3 integrin and inhibited by RGD peptides. Given the ubiquitous expression of α5 laminins in melanoma cells and in melanoma-target tissues/anatomical structures, as well as the strong migration-promoting activity of these laminin isoforms, the α5 laminins emerge as putative primary extracellular matrix mediators of melanoma invasion and metastasis via α3β1 and other integrin receptors.

  1. Different phosphoinositide 3-kinase isoforms mediate carrageenan nociception and inflammation.

    PubMed

    Pritchard, Rory A; Falk, Lovissa; Larsson, Mathilda; Leinders, Mathias; Sorkin, Linda S

    2016-01-01

    Phosphoinositide 3-kinases (PI3Ks) participate in signal transduction cascades that can directly activate and sensitize nociceptors and enhance pain transmission. They also play essential roles in chemotaxis and immune cell infiltration leading to inflammation. We wished to determine which PI3K isoforms were involved in each of these processes. Lightly anesthetized rats (isoflurane) were injected subcutaneously with carrageenan in their hind paws. This was preceded by a local injection of 1% DMSO vehicle or an isoform-specific antagonist to PI3K-α (compound 15-e), -β (TGX221), -δ (Cal-101), or -γ (AS252424). We measured changes in the mechanical pain threshold and spinal c-Fos expression (4 hours after injection) as indices of nociception. Paw volume, plasma extravasation (Evans blue, 0.3 hours after injection), and neutrophil (myeloperoxidase; 1 hour after injection) and macrophage (CD11b+; 4 hour after injection) infiltration into paw tissue were the measured inflammation endpoints. Only PI3K-γ antagonist before treatment reduced the carrageenan-induced pain behavior and spinal expression of c-Fos (P ≤ 0.01). In contrast, pretreatment with PI3K-α, -δ, and-γ antagonists reduced early indices of inflammation. Plasma extravasation PI3K-α (P ≤ 0.05), -δ (P ≤ 0.05), and -γ (P ≤ 0.01), early (0-2 hour) edema -α (P ≤ 0.05), -δ (P ≤ 0.001), and -γ (P ≤ 0.05), and neutrophil infiltration (all P ≤ 0.001) were all reduced compared to vehicle pretreatment. Later (2-4 hour), edema and macrophage infiltration (P ≤ 0.05) were reduced by only the PI3K-δ and -γ isoform antagonists, with the PI3K-δ antagonist having a greater effect on edema. PI3K-β antagonism was ineffective in all paradigms. These data indicate that pain and clinical inflammation are pharmacologically separable and may help to explain clinical conditions in which inflammation naturally wanes or goes into remission, but pain continues unabated.

  2. Characterization of Non-Nitrocatechol Pan and Isoform Specific Catechol-O-methyltransferase Inhibitors and Substrates

    PubMed Central

    2011-01-01

    Reduced dopamine neurotransmission in the prefrontal cortex has been implicated as causal for the negative symptoms and cognitive deficit associated with schizophrenia; thus, a compound which selectively enhances dopamine neurotransmission in the prefrontal cortex may have therapeutic potential. Inhibition of catechol-O-methyltransferase (COMT, EC 2.1.1.6) offers a unique advantage, since this enzyme is the primary mechanism for the elimination of dopamine in cortical areas. Since membrane bound COMT (MB-COMT) is the predominant isoform in human brain, a high throughput screen (HTS) to identify novel MB-COMT specific inhibitors was completed. Subsequent optimization led to the identification of novel, non-nitrocatechol COMT inhibitors, some of which interact specifically with MB-COMT. Compounds were characterized for in vitro efficacy versus human and rat MB and soluble (S)-COMT. Select compounds were administered to male Wistar rats, and ex vivo COMT activity, compound levels in plasma and cerebrospinal fluid (CSF), and CSF dopamine metabolite levels were determined as measures of preclinical efficacy. Finally, novel non-nitrocatechol COMT inhibitors displayed less potent uncoupling of the mitochondrial membrane potential (MMP) compared to tolcapone as well as nonhepatotoxic entacapone, thus mitigating the risk of hepatotoxicity. PMID:22860182

  3. A novel single WAP domain-containing protein isoform with antibacterial relevance in Litopenaeus vannamei.

    PubMed

    Du, Zhi-Qiang; Yuan, Jian-Jun; Ren, Da-Ming

    2015-06-01

    Single WAP domain (SWD)-containing protein is a small protein containing a whey acidic protein (WAP) domain at the C-terminal region. SWD-containing protein exhibits structural similarity to the family of serine proteinase inhibitors. As of this writing, some SWD domain-containing proteins have been identified in crustaceans, and their functions included antibacterial and anti-proteinase activities. We identified a SWD protein isoform gene in Litopenaeus vanname (Lv-SWDi). Very high sequence similarity was found between Lv-SWDi and Lv-SWD. Results of time-course analysis for the gene expression profile showed that Lv-SWDi could produce a rapid feedback and an obvious upregulation at 12 h after Vibrio injection. Endogenous Lv-SWDi protein was obviously upregulated, and the highest expression level was reached at 24 h after Vibrio injection. The purified rLv-SWDi could directly bind to Gram-positive and Gram-negative bacteria. Results of the proteinase inhibitory assay also showed that rLv-SWDi could inhibit secretory protease activity from Bacillus subtilis. Lv-SWDi is a part of an important immunity-relevant gene and may serve important functions in defense against bacteria.

  4. Muscle Lim Protein isoform negatively regulates striated muscle actin dynamics and differentiation

    PubMed Central

    Vafiadaki, Elizabeth; Arvanitis, Demetrios A.; Papalouka, Vasiliki; Terzis, Gerasimos; Roumeliotis, Theodoros I.; Spengos, Konstantinos; Garbis, Spiros D.; Manta, Panagiota; Kranias, Evangelia G.; Sanoudou, Despina

    2015-01-01

    Muscle Lim Protein (MLP) has emerged as a critical regulator of striated muscle physiology and pathophysiology. Mutations in cysteine and glycine-rich protein 3 (CSRP3), the gene encoding MLP, have been directly associated with human cardiomyopathies, while aberrant expression patterns are reported in human cardiac and skeletal muscle diseases. Increasing evidence suggests that MLP has an important role in both myogenic differentiation and myocyte cytoarchitecture, although the full spectrum of its intracellular roles has not been delineated. We report the discovery of an alternative splice variant of MLP, designated as MLP-b, showing distinct expression in neuromuscular disease and direct roles in actin dynamics and muscle differentiation. This novel isoform originates by alternative splicing of exons 3 and 4. At the protein level, it contains the N-terminus first half LIM domain of MLP and a unique sequence of 22 amino acids. Physiologically it is expressed during early differentiation, whereas its overexpression reduces C2C12 differentiation and myotube formation. This may be mediated through its inhibition of MLP/CFL2-mediated F-actin dynamics. In differentiated striated muscles, MLP-b localizes to the sarcomeres and binds directly to Z-disc components including α-actinin, T-cap and MLP. Our findings unveil a novel player in muscle physiology and pathophysiology that is implicated in myogenesis as a negative regulator of myotube formation, and in differentiated striated muscles as a contributor to sarcomeric integrity. PMID:24860983

  5. TFPIβ is the GPI-anchored TFPI isoform on human endothelial cells and placental microsomes

    PubMed Central

    Girard, Thomas J.; Tuley, Elodee

    2012-01-01

    Tissue factor pathway inhibitor (TFPI) produces factor Xa-dependent feedback inhibition of factor VIIa/tissue factor-induced coagulation. Messages for 2 isoforms of TFPI have been identified. TFPIα mRNA encodes a protein with an acidic N-terminus, 3 Kunitz-type protease inhibitor domains and a basic C-terminus that has been purified from plasma and culture media. TFPIβ mRNA encodes a form in which the Kunitz-3 and C-terminal domains of TFPIα are replaced with an alternative C-terminus that directs the attachment of a glycosylphosphatidylinositol (GPI) anchor, but whether TFPIβ protein is actually expressed is not clear. Moreover, previous studies have suggested that the predominant form of TFPI released from cells by phosphatidylinositol-specific phospholipase C (PIPLC) treatment is TFPIα, implying it is bound at cell surfaces to a separate GPI-anchored coreceptor. Our studies show that the form of TFPI released by PIPLC treatment of cultured endothelial cells and placental microsomes is actually TFPIβ based on (1) migration on SDS-PAGE before and after deglycosylation, (2) the lack of a Kunitz-3 domain, and (3) it contains a GPI anchor. Immunoassays demonstrate that, although endothelial cells secrete TFPIα, greater than 95% of the TFPI released by PIPLC treatment from the surface of endothelial cells and from placental microsomes is TFPIβ. PMID:22144186

  6. The effects of acute hydrogen sulfide poisoning on cytochrome P450 isoforms activity in rats.

    PubMed

    Wang, Xianqin; Chen, Mengchun; Chen, Xinxin; Ma, Jianshe; Wen, Congcong; Pan, Jianchun; Hu, Lufeng; Lin, Guanyang

    2014-01-01

    Hydrogen sulfide (H2S) is the second leading cause of toxin related death (after carbon monoxide) in the workplace. H2S is absorbed by the upper respiratory tract mucosa, and it causes histotoxic hypoxemia and respiratory depression. Cocktail method was used to evaluate the influences of acute H2S poisoning on the activities of cytochrome P450 isoforms CYP2B6, CYP2D6, CYP3A4, CYP1A2, CYP2C19, and CYP2C9, which were reflected by the changes of pharmacokinetic parameters of six specific probe drugs, bupropion, metoprolol, midazolam, phenacetin, omeprazole, and tolbutamide, respectively. The experimental rats were randomly divided into two groups, control group and acute H2S poisoning group (inhaling 300 ppm for 2 h). The mixture of six probes was given to rats by oral administration and the blood samples were obtained at a series of time points through the caudal vein. The concentrations of probe drugs in rat plasma were measured by LC-MS. The results for acute H2S poisoning and control groups were as follows: there was a statistically significant difference in the AUC and C max for bupropion, metoprolol, phenacetin, and tolbutamide, while there was no statistical pharmacokinetic difference for midazolam and omeprazole. Acute H2S poisoning could inhibit the activity of CYP2B6, CYP2D6, CYP1A2, and CYP2C9 in rats.

  7. A role for 3-O-sulfotransferase isoform-4 in assisting HSV-1 entry and spread

    SciTech Connect

    Tiwari, Vaibhav; O'Donnell, Christopher D.; Oh, Myung-Jin; Valyi-Nagy, Tibor; Shukla, Deepak . E-mail: dshukla@uic.edu

    2005-12-16

    Many heparan sulfate (HS) 3-O-sulfotransferase (3-OST) isoforms generate cellular receptors for herpes simplex virus type-1 (HSV-1) glycoprotein D (gD). Interestingly, the ability of 3-OST-4 to mediate HSV-1 entry and cell-to-cell fusion has not been determined, although it is predominantly expressed in the brain, a primary target of HSV-1 infections. We report that expression of 3-OST-4 can render Chinese hamster ovary K1 (CHO-K1) cells susceptible to entry of wild-type and a mutant (Rid1) strain of HSV-1. Evidence for generation of gD receptors by 3-OST-4 was suggested by gD-mediated interference assay and the ability of 3-OST-4 expressing CHO-K1 cells to preferentially bind HSV-1 gD, which could be reversed by prior treatment of cells with HS lyases (heparinases-II/III). In addition, 3-OST-4 expressing CHO-K1 cells acquired the ability to fuse with cells-expressing HSV-1 glycoproteins. Demonstrating specificity, the cell fusion was inhibited by soluble 3-O-sulfated forms of HS, but not unmodified HS. Taken together our results suggest a role of 3-OST-4 in HSV-1 pathogenesis.

  8. The role of NO synthase isoforms in PDT-induced injury of neurons and glial cells

    NASA Astrophysics Data System (ADS)

    Kovaleva, V. D.; Berezhnaya, E. V.; Uzdensky, A. B.

    2015-03-01

    Nitric oxide (NO) is an important second messenger, involved in the implementation of various cell functions. It regulates various physiological and pathological processes such as neurotransmission, cell responses to stress, and neurodegeneration. NO synthase is a family of enzymes that synthesize NO from L-arginine. The activity of different NOS isoforms depends both on endogenous and exogenous factors. In particular, it is modulated by oxidative stress, induced by photodynamic therapy (PDT). We have studied the possible role of NOS in the regulation of survival and death of neurons and surrounding glial cells under photo-oxidative stress induced by photodynamic treatment (PDT). The crayfish stretch receptor consisting of a single identified sensory neuron enveloped by glial cells is a simple but informative model object. It was photosensitized with alumophthalocyanine photosens (10 nM) and irradiated with a laser diode (670 nm, 0.4 W/cm2). Antinecrotic and proapoptotic effects of NO on the glial cells were found using inhibitory analysis. We have shown the role of inducible NO synthase in photoinduced apoptosis and involvement of neuronal NO synthase in photoinduced necrosis of glial cells in the isolated crayfish stretch receptor. The activation of NO synthase was evaluated using NADPH-diaphorase histochemistry, a marker of neurons expressing the enzyme. The activation of NO synthase in the isolated crayfish stretch receptor was evaluated as a function of time after PDT. Photodynamic treatment induced transient increase in NO synthase activity and then slowly inhibited this enzyme.

  9. Comprehensive analysis of tropomyosin isoforms in skeletal muscles by top-down proteomics.

    PubMed

    Jin, Yutong; Peng, Ying; Lin, Ziqing; Chen, Yi-Chen; Wei, Liming; Hacker, Timothy A; Larsson, Lars; Ge, Ying

    2016-04-01

    Mammalian skeletal muscles are heterogeneous in nature and are capable of performing various functions. Tropomyosin (Tpm) is a major component of the thin filament in skeletal muscles and plays an important role in controlling muscle contraction and relaxation. Tpm is known to consist of multiple isoforms resulting from different encoding genes and alternative splicing, along with post-translational modifications. However, a systematic characterization of Tpm isoforms in skeletal muscles is still lacking. Therefore, we employed top-down mass spectrometry (MS) to identify and characterize Tpm isoforms present in different skeletal muscles from multiple species, including swine, rat, and human. Our study revealed that Tpm1.1 and Tpm2.2 are the two major Tpm isoforms in swine and rat skeletal muscles, whereas Tpm1.1, Tpm2.2, and Tpm3.12 are present in human skeletal muscles. Tandem MS was utilized to identify the sequences of the major Tpm isoforms. Furthermore, quantitative analysis revealed muscle-type specific differences in the abundance of un-modified and modified Tpm isoforms in rat and human skeletal muscles. This study represents the first systematic investigation of Tpm isoforms in skeletal muscles, which not only demonstrates the capabilities of top-down MS for the comprehensive characterization of skeletal myofilament proteins but also provides the basis for further studies on these Tpm isoforms in muscle-related diseases.

  10. Characterization of the human CUTA isoform2 present in the stably transfected HeLa cells.

    PubMed

    Yang, Jingchun; Yang, Huirong; Yan, Lichong; Yang, Liu; Yu, Long

    2009-01-01

    CUTA, Homo sapiens divalent cation tolerance homolog, has been implicated in anchoring of acetylcholinesterase in neuronal cell membranes. However, a protein highly homologous to CUTA in Rattus norvegicus is structurally similar to the signal transduction protein PII, and this similarity suggests an intriguing role of CUTA in signal transduction. Recent researches indicated that CUTA was one of the 35 key genes responsible for lactation in mammary gland development. However, the physiological role of CUTA is still unclear, so more information of this gene is needed. In this study, the expression profile of CUTA gene in human tissues was examined, and our research revealed that CUTA gene was constitutively expressed in all of the 18 tissues tested. As reported, CUTA gene has five variant transcripts encoding three isoforms with different N terminals. CUTA isoform2 is encoded by three of the five variant transcripts as the common part of the three isoforms. So CUTA isoform2 was chose as representative to characterize the CUTA protein. We constructed a HeLa cell line stably transfected with the encoding sequence of CUTA isoform2 for further study. The subcellular location and oligomeric structure of the CUTA isoform2 was analyzed in the stable cell lines. It was found that the CUTA isoform2 was mainly located in mitochondria as a new potential mitochondrial protein. Furthermore, CUTA isoform2 formed trimers in cell lysate with the possible occurrence of heteropolymers. These findings would be helpful to the further study on the specific function of CUTA protein.

  11. Mammalian mRNA Splice-Isoform Selection Is Tightly Controlled

    PubMed Central

    Chisa, Jennifer L.; Burke, David T.

    2007-01-01

    Post-transcriptional RNA processing is an important regulatory control mechanism for determining the phenotype of eukaryotic cells. The processing of a transcribed RNA species into alternative splice isoforms yields products that can perform different functions. Each type of cell in a multi-cellular organism is presumed to actively control the relative quantities of alternative splice isoforms. In this study, the alternatively spliced isoforms of five mRNA transcription units were examined by quantitative reverse transcription–PCR amplification. We show that interindividual variation in splice-isoform selection is very highly constrained when measured in a large population of genetically diverse mice (i.e., full siblings; N = 150). Remarkably, splice-isoform ratios are among the most invariant phenotypes measured in this population and are confirmed in a second, genetically distinct population. In addition, the patterns of splice-isoform selection show tissue-specific and age-related changes. We propose that splice-isoform selection is exceptionally robust to genetic and environmental variability and may provide a control point for cellular homeostasis. As a consequence, splice-isoform ratios may be useful as a practical quantitative measure of the physiological status of cells and tissues. PMID:17179090

  12. Evidence for multiple protein kinase C isoforms in the leukocytes of a marine teleost, Sciaenops ocellatus.

    PubMed

    Mericko, P A; Burnett, K G

    1998-05-01

    The protein kinase C (PKC) family of isozymes mediates a diverse range of cellular functions, including activation of vertebrate lymphocytes through membrane-bound antigen receptors. The complex role of PKC in mammalian cells may be orchestrated in part by the presence of multiple isoforms, each of which displays a distinctive tissue distribution, substrate specificity and pattern of regulation. In the present study, PKC isoforms were identified in peripheral blood leukocytes of the marine teleost fish Sciaenops ocellatus by immunoprecipitation and Western blot using antibodies to mammalian isoforms. Functional activity was monitored by evaluating translocation of the teleost isoforms from membrane to cytosol in response to phorbol ester treatment. Teleost conventional isoforms PKC alpha and PKC beta (82 kDa) completely translocated out of the cytosol in response to phorbol ester. Phorbol ester did not induce translocation of teleost atypical isoform PKC zeta (67 kDa), as has been shown for its mammalian homologue. Although their identity as distinct isoforms is less clear, proposed teleost novel PKC delta (84, 86 kDa) and PKC eta (83, 85 kDa) also translocated out of the cytosol. The presence of multiple isoforms representing each of the three major classes of PKC in red drum leukocytes implies that the complexity of signal transduction pathways in vertebrates is highly conserved.

  13. Roles of the troponin isoforms during indirect flight muscle development in Drosophila.

    PubMed

    Singh, Salam Herojeet; Kumar, Prabodh; Ramachandra, Nallur B; Nongthomba, Upendra

    2014-08-01

    Troponin proteins in cooperative interaction with tropomyosin are responsible for controlling the contraction of the striated muscles in response to changes in the intracellular calcium concentration. Contractility of the muscle is determined by the constituent protein isoforms, and the isoforms can switch over from one form to another depending on physiological demands and pathological conditions. In Drosophila, amajority of themyofibrillar proteins in the indirect flight muscles (IFMs) undergo post-transcriptional and post-translational isoform changes during pupal to adult metamorphosis to meet the high energy and mechanical demands of flight. Using a newly generated Gal4 strain (UH3-Gal4) which is expressed exclusively in the IFMs, during later stages of development, we have looked at the developmental and functional importance of each of the troponin subunits (troponin-I, troponin-T and troponin-C) and their isoforms. We show that all the troponin subunits are required for normal myofibril assembly and flight, except for the troponin-C isoform 1 (TnC1). Moreover, rescue experiments conducted with troponin-I embryonic isoform in the IFMs, where flies were rendered flightless, show developmental and functional differences of TnI isoforms and importance of maintaining the right isoform.

  14. Novel alternative splicing isoform biomarkers identification from high-throughput plasma proteomics profiling of breast cancer

    PubMed Central

    2013-01-01

    Background In the biopharmaceutical industry, biomarkers define molecular taxonomies of patients and diseases and serve as surrogate endpoints in early-phase drug trials. Molecular biomarkers can be much more sensitive than traditional lab tests. Discriminating disease biomarkers by traditional method such as DNA microarray has proved challenging. Alternative splicing isoform represents a new class of diagnostic biomarkers. Recent scientific evidence is demonstrating that the differentiation and quantification of individual alternative splicing isoforms could improve insights into disease diagnosis and management. Identifying and characterizing alternative splicing isoforms are essential to the study of molecular mechanisms and early detection of complex diseases such as breast cancer. However, there are limitations with traditional methods used for alternative splicing isoform determination such as transcriptome-level, low level of coverage and poor focus on alternative splicing. Results Therefore, we presented a peptidomics approach to searching novel alternative splicing isoforms in clinical proteomics. Our results showed that the approach has significant potential in enabling discovery of new types of high-quality alternative splicing isoform biomarkers. Conclusions We developed a peptidomics approach for the proteomics community to analyze, identify, and characterize alternative splicing isoforms from MS-based proteomics experiments with more coverage and exclusive focus on alternative splicing. The approach can help generate novel hypotheses on molecular risk factors and molecular mechanisms of cancer in early stage, leading to identification of potentially highly specific alternative splicing isoform biomarkers for early detection of cancer. PMID:24565027

  15. Targeting of the Nuclear Receptor Coativator Isoform Delta 3aib1 in Breast Cancer. Addendum

    DTIC Science & Technology

    2007-07-01

    using a regulatable AIB1 directed ribozyme , resulted in reduced tumor growth in vivo. Overall, these data indicate a major role for AIB1 and its isoform...regulatable AIB1 directed ribozyme , resulted in reduced tumor growth in vivo. Overall, these data indicate a major role for AIB1 and its isoform ∆3AIB1 in

  16. AN ENZYME LINKED IMMUNOSORBENT ASSAY FOR THE HO-1 ISOFORM OF HEME OXYGENASE

    EPA Science Inventory

    AN ENZYME LINKED IMMUNOSORBENT ASSAY FOR THE HO-1 ISOFORM OF HEME OXYGENASE

    Heme oxygenase (HO) occurs in biological tissues as two major isoforms HO-1 and HO-2. HO-1 is inducible by many treatments, particularly oxidative stress-related conditions such as depletion of gl...

  17. Estrogen and progesterone receptor isoforms expression in the stomach of Mongolian gerbils

    PubMed Central

    Saqui-Salces, Milena; Neri-Gómez, Teresa; Gamboa-Dominguez, Armando; Ruiz-Palacios, Guillermo; Camacho-Arroyo, Ignacio

    2008-01-01

    AIM: We studied the estrogen receptor (ER) and progesterone receptor (PR) isoforms expression in gastric antrum and corpus of female gerbils and their regulation by estradiol (E2) and progesterone (P4). METHODS: Ovariectomized adult female gerbils were subcutaneously treated with E2, and E2 + P4. Uteri and stomachs were removed, the latter were cut along the greater curvature, and antrum and corpus were excised. Proteins were immunoblotted using antibodies that recognize ER-alpha, ER-beta, and PR-A and PR-B receptor isoforms. Tissues from rats treated in the same way were used as controls. RESULTS: Specific bands were detected for ER-alpha (68 KDa), and PR isoforms (85 and 120 KDa for PR-A and PR-B isoforms, respectively) in uteri, gastric antrum and corpus. We could not detect ER-beta isoform. PR isoforms were not regulated by E2 or P4 in uterus and gastric tissues of gerbils. ER-alpha isoform content was significantly down-regulated by E2 in the corpus, but not affected by hormones in uterus and gastric antrum. CONCLUSION: The presence of ER-alpha and PR isoforms in gerbils stomach suggests that E2 and P4 actions in this organ are in part mediated by their nuclear receptors. PMID:18837087

  18. Does Compound I Vary Significantly between Isoforms of Cytochrome P450?

    PubMed Central

    2011-01-01

    The cytochrome P450 (CYP) enzymes are important in many areas, including pharmaceutical development. Subtle changes in the electronic structure of the active species, Compound I, have been postulated previously to account partly for the experimentally observed differences in reactivity between isoforms. Current predictive models of CYP metabolism typically assume an identical Compound I in all isoforms. Here we present a method to calculate the electronic structure and to estimate the Fe–O bond enthalpy of Compound I, and apply it to several human and bacterial CYP isoforms. Conformational flexibility is accounted for by sampling large numbers of structures from molecular dynamics simulations, which are subsequently optimized with density functional theory (B3LYP) based quantum mechanics/molecular mechanics. The observed differences in Compound I between human isoforms are small: They are generally smaller than the spread of values obtained for the same isoform starting from different initial structures. Hence, it is unlikely that the variation in activity between human isoforms is due to differences in the electronic structure of Compound I. A larger difference in electronic structure is observed between the human isoforms and P450cam and may be explained by the slightly different hydrogen-bonding environment surrounding the cysteinyl sulfur. The presence of substrate in the active site of all isoforms studied appears to cause a slight decrease in the Fe–O bond enthalpy, apparently due to displacement of water out of the active site, suggesting that Compound I is less stable in the presence of substrate. PMID:21863858

  19. Functional analysis of the two cyclophilin isoforms of Sinorhizobium meliloti.

    PubMed

    Thomloudi, Eirini-Evangelia; Skagia, Aggeliki; Venieraki, Anastasia; Katinakis, Panagiotis; Dimou, Maria

    2017-02-01

    The nitrogen fixing Sinorhizobium meliloti possesses two genes, ppiA and ppiB, encoding two cyclophilin isoforms which belong to the superfamily of peptidyl prolyl cis/trans isomerases (PPIase, EC: 5.2.1.8). Here, we functionally characterize the two proteins and we demonstrate that both recombinant cyclophilins are able to isomerise the Suc-AAPF-pNA synthetic peptide but neither of them displays chaperone function in the citrate synthase thermal aggregation assay. Furthermore, we observe that the expression of both enzymes increases the viability of E. coli BL21 in the presence of abiotic stress conditions such as increased heat and salt concentration. Our results support and strengthen previous high-throughput studies implicating S. meliloti cyclophilins in various stress conditions.

  20. Quantitative isoform-profiling of highly diversified recognition molecules

    PubMed Central

    Schreiner, Dietmar; Simicevic, Jovan; Ahrné, Erik; Schmidt, Alexander; Scheiffele, Peter

    2015-01-01

    Complex biological systems rely on cell surface cues that govern cellular self-recognition and selective interactions with appropriate partners. Molecular diversification of cell surface recognition molecules through DNA recombination and complex alternative splicing has emerged as an important principle for encoding such interactions. However, the lack of tools to specifically detect and quantify receptor protein isoforms is a major impediment to functional studies. We here developed a workflow for targeted mass spectrometry by selected reaction monitoring that permits quantitative assessment of highly diversified protein families. We apply this workflow to dissecting the molecular diversity of the neuronal neurexin receptors and uncover an alternative splicing-dependent recognition code for synaptic ligands. DOI: http://dx.doi.org/10.7554/eLife.07794.001 PMID:25985086

  1. Differential expression of two scribble isoforms during Drosophila embryogenesis.

    PubMed

    Li, M; Marhold, J; Gatos, A; Török, I; Mechler, B M

    2001-10-01

    The tumour suppressor gene scribble (scrib) is required for epithelial polarity and growth control in Drosophila. Here, we report the identification and embryonic expression pattern of two Scrib protein isoforms resulting from alternative splicing during scrib transcription. Both proteins are first ubiquitously expressed during early embryogenesis. Then, during morphogenesis each Scrib protein displays a specific pattern of expression in the central and peripheral nervous systems, CNS and PNS, respectively. During germ band extension, the expression of the longer form Scrib1 occurs predominantly in the neuroblasts derived from the neuro-ectoderm and becomes later restricted to CNS neurones as well as to the pole cells in the gonads. By contrast, the shorter form Scrib2 is strongly expressed in the PNS and a subset of CNS neurones.

  2. Isoforms, structures, and functions of versatile spectraplakin MACF1

    PubMed Central

    Hu, Lifang; Su, Peihong; Li, Runzhi; Yin, Chong; Zhang, Yan; Shang, Peng; Yang, Tuanmin; Qian, Airong

    2016-01-01

    Spectraplakins are crucially important communicators, linking cytoskeletal components to each other and cellular junctions. Microtubule actin crosslinking factor 1 (MACF1), also known as actin crosslinking family 7 (ACF7), is a member of the spectraplakin family. It is expressed in numerous tissues and cells as one extensively studied spectraplakin. MACF1 has several isoforms with unique structures and well-known function to be able to crosslink F-actin and microtubules. MACF1 is one versatile spectraplakin with various functions in cell processes, embryo development, tissue-specific functions, and human diseases. The importance of MACF1 has become more apparent in recent years. Here, we summarize the current knowledge on the presence and function of MACF1 and provide perspectives on future research of MACF1 based on our studies and others. [BMB Reports 2016; 49(1): 37-44] PMID:26521939

  3. Chromatographic purification of an insoluble histidine tag recombinant Ykt6p SNARE from Arabidopsis thaliana over-expressed in E. coli.

    PubMed

    Vincent, Patrick; Dieryck, Wilfrid; Maneta-Peyret, Lilly; Moreau, Patrick; Cassagne, Claude; Santarelli, Xavier

    2004-08-25

    In order to undertake in plant cell the study of the endoplasmic reticulum (ER)-Golgi apparatus (GA) protein and/or lipid vesicular transport pathway, expressed sequence tag (EST) coding for a homologue to the yeast soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) Ykt6p has been cloned in Arabidopsis thaliana by reverse transcription polymerase chain reaction (RT-PCR). The corresponding protein was over-expressed as a recombinant histidine-tag (his-tag) protein in E. coli. Starting from one litter of culture, an ultrasonic homogenization was performed for cell disruption and after centrifugation the Arabidopsis Ykt6p SNARE present in inclusion bodies in the pellet was solubilized. After centrifugation, the clarified feedstock obtained was injected onto an immobilized metal affinity chromatography (IMAC) in presence of 6 M guanidine and on-column refolding was performed. Folded and subsequently purified (94% purity) recombinant protein was obtained with 82% of recovery.

  4. Extracellular regulation of VEGF: isoforms, proteolysis, and vascular patterning

    PubMed Central

    Vempati, Prakash; Popel, Aleksander S.; Mac Gabhann, Feilim

    2014-01-01

    The regulation of vascular endothelial growth factor A (VEGF) is critical to neovascularization in numerous tissues under physiological and pathological conditions. VEGF has multiple isoforms, created by alternative splicing or proteolytic cleavage, and characterized by different receptor-binding and matrix-binding properties. These isoforms are known to give rise to a spectrum of angiogenesis patterns marked by differences in branching, which has functional implications for tissues. In this review, we detail the extensive extracellular regulation of VEGF and the ability of VEGF to dictate the vascular phenotype. We explore the role of VEGF-releasing proteases and soluble carrier molecules on VEGF activity. While proteases such as MMP9 can ‘release’ matrix-bound VEGF and promote angiogenesis, for example as a key step in carcinogenesis, proteases can also suppress VEGF’s angiogenic effects. We explore what dictates pro- or anti-angiogenic behavior. We also seek to understand the phenomenon of VEGF gradient formation. Strong VEGF gradients are thought to be due to decreased rates of diffusion from reversible matrix binding, however theoretical studies show that this scenario cannot give rise to lasting VEGF gradients in vivo. We propose that gradients are formed through degradation of sequestered VEGF. Finally, we review how different aspects of the VEGF signal, such as its concentration, gradient, matrix-binding, and NRP1-binding can differentially affect angiogenesis. We explore how this allows VEGF to regulate the formation of vascular networks across a spectrum of high to low branching densities, and from normal to pathological angiogenesis. A better understanding of the control of angiogenesis is necessary to improve upon limitations of current angiogenic therapies. PMID:24332926

  5. DISTRIBUTION OF NOS ISOFORMS IN A PORCINE ENDOTOXIN SHOCK MODEL

    PubMed Central

    Doursout, Marie-Francoise; Oguchi, Takeshi; Fischer, Uwe M.; Liang, YangYan; Chelly, Brice; Hartley, Craig J.; Chelly, Jacques E.

    2012-01-01

    Sepsis is a major cause of morbidity and mortality. NO, an endogenous vasodilator, has been associated with the hypotension, catecholamine hyporesponsiveness, and myocardial depression of septic shock. Although iNOS is thought to be responsible for the hypotension and loss of vascular tone occurring several hours after endotoxin administration, little is known on the effects of constitutive eNOS on LPS-induced organ dysfunction. This study assessed the distribution of eNOS and iNOS in various vascular beds in conscious pigs challenged with LPS. Cardiac and regional hemodynamic parameters were recorded over 8 h in the presence and absence of aminoguanidine, a rather selective inhibitor of iNOS activity, and N-methyl-L-arginine, a nonspecific NOS inhibitor. Our data show that LPS-induced cardiac depression was associated with coronary, renal, and mesenteric vasoconstrictions and a hepatic vasodilatation. LPS also induced increases in eNOS in the heart and lungs, whereas iNOS was mostly detected in the liver. Nitrotyrosine formation was mainly detected in the lungs, with traces in the kidney, liver, and gut. Accordingly, our results suggest that the early decrease in blood pressure and cardiac depression are likely due to activated eNOS, whereas both isoforms are involved in the hepatic vasodilation. In contrast, carotid, coronary, mesenteric, and renal vasoconstrictions were significant at 5 and/or 6 h after LPS infusion, suggesting that NO is not the primary mediator, facilitating and/or unmasking the release of vasoconstrictor mediators. Consequently, developing newer tissue- or isoform-specific NOS inhibitors can lead to novel therapeutic agents in septic shock. PMID:17909454

  6. A neuron-specific cytoplasmic dynein isoform preferentially transports TrkB signaling endosomes

    PubMed Central

    Ha, Junghoon; Lo, Kevin W.-H.; Myers, Kenneth R.; Carr, Tiffany M.; Humsi, Michael K.; Rasoul, Bareza A.; Segal, Rosalind A.; Pfister, K. Kevin

    2008-01-01

    Cytoplasmic dynein is the multisubunit motor protein for retrograde movement of diverse cargoes to microtubule minus ends. Here, we investigate the function of dynein variants, defined by different intermediate chain (IC) isoforms, by expressing fluorescent ICs in neuronal cells. Green fluorescent protein (GFP)–IC incorporates into functional dynein complexes that copurify with membranous organelles. In living PC12 cell neurites, GFP–dynein puncta travel in both the anterograde and retrograde directions. In cultured hippocampal neurons, neurotrophin receptor tyrosine kinase B (TrkB) signaling endosomes are transported by cytoplasmic dynein containing the neuron-specific IC-1B isoform and not by dynein containing the ubiquitous IC-2C isoform. Similarly, organelles containing TrkB isolated from brain by immunoaffinity purification also contain dynein with IC-1 but not IC-2 isoforms. These data demonstrate that the IC isoforms define dynein populations that are selectively recruited to transport distinct cargoes. PMID:18559670

  7. The mouse dead-end gene isoform α is necessary for germ cell and embryonic viability

    PubMed Central

    Bhattacharya, Chitralekha; Aggarwal, Sita; Zhu, Rui; Kumar, Madhu; Zhao, Ming; Meistrich, Marvin L.; Matin, Angabin

    2007-01-01

    Inactivation of the dead-end (Dnd1) gene in the Ter mouse strain results in depletion of primordial germ cells (PGCs) so that mice become sterile. However, on the 129 mouse strain background, loss of Dnd1 also increases testicular germ cell tumor incidence in parallel to PGC depletion. We report that inactivation of Dnd1 also affects embryonic viability in the 129 strain. Mouse Dnd1 encodes two protein isoforms, DND1-isoform α (DND1- α) and DND1-isoform β (DND1-β). Using isoform specific antibodies, we determined DND1-α is expressed in embryos and embryonic gonads whereas DND1-β expression is restricted to germ cells of the adult testis. Our data implicates DND1-α isoform to be necessary for germ cell viability and therefore its loss in Ter mice results in PGC depletion, germ cell tumor development and partial embryonic lethality in the 129 strain. PMID:17291453

  8. Theoretical predictions of trends in spectroscopic properties of gold containing dimers of the 6p and 7p elements and their adsorption on gold.

    PubMed

    Pershina, V; Borschevsky, A; Anton, J; Jacob, T

    2010-09-14

    Fully relativistic, four-component density functional theory electronic structure calculations were performed for the MAu dimers of the 7p elements, 113 through 118, and their 6p homologs, Tl through Rn. It was shown that the M-Au bond strength should decrease from the 6p to 7p homologs in groups 13 and 14, while it should stay about the same in groups 15 through 17 and even increase in group 18. This is in contrast with the decreasing trend in the M-M bond strength in groups 15 through 17. The reason for these trends is increasingly important relativistic effects on the np AOs of these elements, particularly their large spin-orbit splitting. Trends in the adsorption energies of the heaviest elements and their homologs on gold are expected to be related to those in the binding energies of MAu, while sublimation enthalpies are closely connected to the binding energies of the MM dimers. Lack of a correlation between the MAu and MM binding energies means that no correlation can also be expected between adsorption enthalpies on gold and sublimation enthalpies in groups 15 through 17. No linear correlation between these quantities is established in the row of the 6p elements, as well as no one is expected in the row of the 7p elements.

  9. Defining a 0.5-mb region of genomic gain on chromosome 6p22 in bladder cancer by quantitative-multiplex polymerase chain reaction.

    PubMed

    Evans, Andrew J; Gallie, Brenda L; Jewett, Michael A S; Pond, Gregory R; Vandezande, Kirk; Underwood, John; Fradet, Yves; Lim, Gloria; Marrano, Paula; Zielenska, Maria; Squire, Jeremy A

    2004-01-01

    Metaphase-based comparative genomic hybridization (CGH) has identified recurrent regions of gain on different chromosomes in bladder cancer, including 6p22. These regions may contain activated oncogenes important in disease progression. Using quantitative multiplex polymerase chain reaction (QM-PCR) to study DNA from 59 bladder tumors, we precisely mapped the focal region of genomic gain on 6p22. The marker STS-X64229 had copy number increases in 38 of 59 (64%) tumors and the flanking markers, RH122450 and A009N14, had copy number gains in 33 of 59 (56%) and 26 of 59 (45%) respectively. Contiguous gain was present for all three markers in 14 of 59 (24%) and for two (RH122450 and STS-X64229) in 25 of 59 (42%). The genomic distance between the markers flanking STS-X64229 is 0.5 megabases, defining the minimal region of gain on 6p22. Locus-specific interphase fluorescence in situ hybridization confirmed the increased copy numbers detected by QM-PCR. Current human genomic mapping data indicates that an oncogene, DEK, is centrally placed within this minimal region. Our findings demonstrate the power of QM-PCR to narrow the regions identified by CGH to facilitate identifying specific candidate oncogenes. This also represents the first study identifying DNA copy number increases for DEK in bladder cancer.

  10. The potential of species-specific tagatose-6-phosphate (T6P) pathway in Lactobacillus casei group for galactose reduction in fermented dairy foods.

    PubMed

    Wu, Qinglong; Shah, Nagendra P

    2017-04-01

    Residual lactose and galactose in fermented dairy foods leads to several industrial and health concerns. There is very little information pertaining to manufacture of fermented dairy foods that are low in lactose and galactose. In the present study, comparative genomic survey demonstrated the constant presence of chromosome-encoded tagatose-6-phosphate (T6P) pathway in Lactobacillus casei group. Lactose/galactose utilization tests and β-galactosidase assay suggest that PTS(Gal) system, PTS(Lac) system and T6P pathway are major contributors for lactose/galactose catabolism in this group of organisms. In addition, it was found than lactose catabolism by Lb. casei group accumulated very limited galactose in the MRS-lactose medium and in reconstituted skim milk, whereas Streptococcus thermophilus and Lb. delbrueckii subsp. bulgaricus (Lb. bulgaricus) strains secreted high amount of galactose extracellularly. Moreover, co-culturing Lb. casei group with Str. thermophilus showed significant reduction in galactose content, while co-culturing Lb. casei group with Lb. bulgaricus showed significant reduction in lactose content but significant increase in galactose content in milk. Overall, the present study highlighted the potential of Lb. casei group for reducing galactose accumulation in fermented milks due to its species-specific T6P pathway.

  11. Malathion bioactivation in the human liver: the contribution of different cytochrome p450 isoforms.

    PubMed

    Buratti, Franca M; D'Aniello, Alessandra; Volpe, Maria Teresa; Meneguz, Annarita; Testai, Emanuela

    2005-03-01

    Among organophosphorothioate (OPT) pesticides, malathion is considered relatively safe for use in mammals. Its rapid degradation by carboxylesterases competes with the cytochrome P450 (P450)-catalyzed formation of malaoxon, the toxic metabolite. However, impurities in commercial formulations are potent inhibitors of carboxylesterase, allowing a dramatic increase in malaoxon formation. Malathion desulfuration has been characterized in human liver microsomes (HLMs) with a method based on acetylcholinesterase inhibition that is able to detect nanomolar levels of oxon. The active P450 isoforms have been identified by means of a multifaceted strategy, including the use of cDNA-expressed human P450s and correlation, immunoinhibition, and chemical inhibition studies in a panel of phenotyped HLMs. HLMs catalyzed malaoxon formation with a high level of variability (>200-fold). One or two components (K(mapp1) = 53-67 microM; K(mapp2) = 427-1721 microM) were evidenced, depending on the relative specific P450 content. Results from different approaches indicated that, at low malathion concentration, malaoxon formation is catalyzed by CYP1A2 and, to a lesser extent, 2B6, whereas the role of 3A4 is relevant only at high malathion levels. These results are in line with those found with chlorpyrifos, diazinon, azynphos-methyl, and parathion, characterized by the presence of an aromatic ring in the molecule. Since malathion has linear chains as substituents at the thioether sulfur, it can be hypothesized that, independently from the chemical structure, OPTs are bioactivated by the same P450s. These results also suggest that CYP1A2 and 2B6 can be considered as possible metabolic biomarkers of susceptibility to OPT-induced toxic effects at actual human exposure levels.

  12. Protein production, crystallization and preliminary X-ray analysis of two isoforms of the Dscam1 Ig7 domain

    PubMed Central

    Li, Shu-Ang; Cheng, Linna; Yu, Yamei; Chen, Qiang

    2015-01-01

    Drosophila Down syndrome cell adhesion molecule 1 (Dscam1) plays a critical role in neural development. It can potentially form 38 016 isoforms through alternative RNA splicing, and exhibits isoform-specific homophilic interaction through three variable Ig domains (Ig2, Ig3 and Ig7). The diversity and homophilic interaction are essential for its functions. Ig7 has 33 isoforms and is the most variable among the three variable Ig domains. However, only one isoform of Ig7 (isoform 30) has been structurally determined to date. Here, two isoforms of Dscam1 Ig7 (isoforms 5 and 9; Ig75 and Ig79) were produced and crystallized. Diffraction data from Ig75 and Ig79 crystals were processed to resolutions of 1.95 and 2.37 Å, respectively. Comparison of different Dscam1 Ig7 isoforms will provide insight into the mechanism of its binding specificity. PMID:25760710

  13. RORγt, a Novel Isoform of an Orphan Receptor, Negatively Regulates Fas Ligand Expression and IL-2 Production in T Cells

    PubMed Central

    He, You-Wen; Deftos, Michael L.; Ojala, Ethan W.; Bevan, Michael J.

    2009-01-01

    Summary We have identified RORγt, a novel, thymus-specific isoform of the orphan nuclear receptor RORγ that is expressed predominantly in CD4+ CD8+ double-positive thymocytes. Ectopic expression of RORγt protects T cell hybridomas from activation-induced cell death by inhibiting the upregulation of Fas ligand. Following hybridoma stimulation, RORγt also inhibits IL-2 production but does not affect the induction of Nur-77 and Egr-3 nor the upregulation of CD69. Both the ligand-binding and DNA-binding domains of RORγt are required for this effect. We propose that the role of RORγt expression in immature thymocytes is to inhibit Fas ligand expression and cytokine secretion following engagement of their TCR during positive or negative selection. PMID:9881970

  14. Design and synthesis of benzothiazole-6-sulfonamides acting as highly potent inhibitors of carbonic anhydrase isoforms I, II, IX and XII.

    PubMed

    Ibrahim, Diaa A; Lasheen, Deena S; Zaky, Maysoun Y; Ibrahim, Amany W; Vullo, Daniela; Ceruso, Mariangela; Supuran, Claudiu T; Abou El Ella, Dalal A

    2015-08-01

    A series of novel 2-aminobenzothiazole derivatives bearing sulfonamide at position 6 was designed, synthesized and investigated as inhibitors of four isoforms of the metalloenzyme carbonic anhydrase (CA, EC 4.2.1.1), the cytosolic CA I and II, and the tumor-associated isozymes CA IX and XII. Docking and binding energy studies were carried out to reveal details regarding the favorable interactions between the scaffolds of these new inhibitors and the active sites of the investigated CA isoforms. Most of the novel compounds were acting as highly potent inhibitors of the tumor-associated hCA IX and hCA XII with KIs in the nanomolar range. The ubiquitous and dominant rapid cytosolic isozyme hCA II was also inhibited with KIs ranging from 3.5 to 45.4 nM. The favorable interactions between some of the new compounds and the active site of different CA isoforms were delineated by using molecular docking which may be useful for designing compounds with high affinity and selectivity for some CAs with biomedical applications.

  15. SON and its alternatively spliced isoforms control MLL complex-mediated H3K4me3 and transcription of leukemia-associated genes

    PubMed Central

    Kim, Jung-Hyun; Baddoo, Melody C.; Park, Eun Young; Stone, Joshua K.; Park, Hyeonsoo; Butler, Thomas W.; Huang, Gang; Yan, Xiaomei; Pauli-Behn, Florencia; Myers, Richard M.; Tan, Ming; Flemington, Erik K.; Lim, Ssang-Taek; Erin Ahn, Eun-Young

    2016-01-01

    SUMMARY Dysregulation of MLL complex-mediated histone methylation plays a pivotal role in gene expression associated with diseases, but little is known about cellular factors modulating MLL complex activity. Here, we report that SON, previously known as an RNA splicing factor, controls MLL complex-mediated transcriptional initiation. SON binds to DNA near transcription start sites, interacts with menin, and inhibits MLL complex assembly, resulting in decreased H3K4me3 and transcriptional repression. Importantly, alternatively spliced short isoforms of SON are markedly upregulated in acute myeloid leukemia. The short isoforms compete with full-length SON for chromatin occupancy, but lack the menin-binding ability, thereby antagonizing full-length SON function in transcriptional repression while not impairing full-length SON-mediated RNA splicing. Furthermore, overexpression of a short isoform of SON enhances replating potential of hematopoietic progenitors. Our findings define SON as a fine-tuner of the MLL-menin interaction and reveal short SON overexpression as a marker indicating aberrant transcriptional initiation in leukemia. PMID:26990989

  16. Localization and trafficking of an isoform of the AtPRA1 family to the Golgi apparatus depend on both N- and C-terminal sequence motifs.

    PubMed

    Jung, Chan Jin; Lee, Myoung Hui; Min, Myung Ki; Hwang, Inhwan

    2011-02-01

    Prenylated Rab acceptors (PRAs) bind to prenylated Rab proteins and possibly aid in targeting Rabs to their respective compartments. In Arabidopsis, 19 isoforms of PRA1 have been identified and, depending upon the isoforms, they localize to the endoplasmic reticulum (ER), Golgi apparatus and endosomes. Here, we investigated the localization and trafficking of AtPRA1.B6, an isoform of the Arabidopsis PRA1 family. In colocalization experiments with various organellar markers, AtPRA1.B6 tagged with hemagglutinin (HA) at the N-terminus localized to the Golgi apparatus in protoplasts and transgenic plants. The valine residue at the C-terminal end and an EEE motif in the C-terminal cytoplasmic domain were critical for anterograde trafficking from the ER to the Golgi apparatus. The N-terminal region contained a sequence motif for retention of AtPRA1.B6 at the Golgi apparatus. In addition, anterograde trafficking of AtPRA1.B6 from the ER to the Golgi apparatus was highly sensitive to the HA:AtPRA1.B6 level. The region that contains the sequence motif for Golgi retention also conferred the abundance-dependent trafficking inhibition. On the basis of these results, we propose that AtPRA1.B6 localizes to the Golgi apparatus and its ER-to-Golgi trafficking and localization to the Golgi apparatus are regulated by multiple sequence motifs in both the C- and N-terminal cytoplasmic domains.

  17. Involvement of H- and N-Ras isoforms in transforming growth factor-{beta}1-induced proliferation and in collagen and fibronectin synthesis

    SciTech Connect

    Martinez-Salgado, Carlos . E-mail: carloms@usal.es; Fuentes-Calvo, Isabel; Garcia-Cenador, Begona; Santos, Eugenio; Lopez-Novoa, Jose M.

    2006-07-01

    Transforming growth factor {beta}1 (TGF-{beta}1) has a relevant role in the origin and maintenance of glomerulosclerosis and tubule-interstitial fibrosis. TGF-{beta} and Ras signaling pathways are closely related: TGF-{beta}1 overcomes Ras mitogenic effects and Ras counteracts TGF-{beta} signaling. Tubule-interstitial fibrosis is associated to increases in Ras, Erk, and Akt activation in a renal fibrosis model. We study the role of N- and H-Ras isoforms, and the involvement of the Ras effectors Erk and Akt, in TGF-{beta}1-mediated extracellular matrix (ECM) synthesis and proliferation, using embrionary fibroblasts from double knockout (KO) mice for H- and N-Ras (H-ras {sup -/-}/N-ras {sup -/-}) isoforms and from heterozygote mice (H-ras {sup +/-}/N-ras {sup +/-}). ECM synthesis is increased in basal conditions in H-ras {sup -/-}/N-ras {sup -/-} fibroblasts, this increase being higher after stimulation with TGF-{beta}1. TGF-{beta}1-induced fibroblast proliferation is smaller in H-ras {sup -/-}/N-ras {sup -/-} than in H-ras {sup +/-}/N-ras {sup +/-} fibroblasts. Erk activation is decreased in H-ras {sup -/-}/N-ras {sup -/-} fibroblasts; inhibition of Erk activation reduces fibroblast proliferation. Akt activation is higher in double KO fibroblasts than in heterozygotes; inhibition of Akt activation also inhibits ECM synthesis. We suggest that H- and N-Ras isoforms downregulate ECM synthesis, and mediate proliferation, in part through MEK/Erk activation. PI3K-Akt pathway activation may be involved in the increase in ECM synthesis observed in the absence of H- and N-Ras.

  18. Possible expression of a particular gamma-aminobutyric acid transporter isoform responsive to upregulation by hyperosmolarity in rat calvarial osteoblasts.

    PubMed

    Fujimori, Sayumi; Hinoi, Eiichi; Takarada, Takeshi; Iemata, Mika; Takahata, Yoshifumi; Yoneda, Yukio

    2006-11-21

    Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter in the brain, but widely distributed in different peripheral organs. We have previously shown the functional expression of GABA(B) receptors required for GABAergic signal input by cultured rat calvarial osteoblasts. This study focused on the possible functional expression of the machinery required for GABAergic signal termination such as GABA transporters. In rat calvarial osteoblasts cultured for 7 days, [(3)H]GABA accumulation was observed in a temperature-, sodium- and chloride-dependent manner, consisting of a single component with a K(m) value of 789.6+/-9.0 microM and a V(max) value of 4.4+/-0.1 nmol/min/mg protein, respectively. Both nipecotic and L-2,4-diaminobutyric acids significantly inhibited [(3)H]GABA accumulation in a concentration-dependent manner. Constitutive expression was seen with mRNA for the betaine/GABA transporter-1 (BGT-1) and taurine transporter (TauT), while hyperosmotic cultivation led to significant increases in both [(3)H]GABA accumulation and BGT-1 mRNA expression without affecting TauT mRNA expression. Highly immunoreactive cells were detected for the BGT-1 isoform at the surface of trabecular bone of neonatal rat tibias. Sustained exposure to GABA significantly inhibited alkaline phosphatase (ALP) activity, but not cellular viability, at concentrations above 0.1 mM in osteoblasts cultured for 3 to 28 days. Nipecotic acid not only decreased ALP activity alone, but also further decreased ALP activity in osteoblasts cultured in the presence of GABA. These results suggest that the BGT-1 isoform may be functionally expressed by rat calvarial osteoblasts to play a hitherto unidentified role in mechanisms underlying hyperosmotic regulation of osteoblastogenesis.

  19. Macula densa Na(+)/H(+) exchange activities mediated by apical NHE2 and basolateral NHE4 isoforms.

    PubMed

    Peti-Peterdi, J; Chambrey, R; Bebok, Z; Biemesderfer, D; St John, P L; Abrahamson, D R; Warnock, D G; Bell, P D

    2000-03-01

    Functional and immunohistochemical studies were performed to localize and identify Na(+)/H(+) exchanger (NHE) isoforms in macula densa cells. By using the isolated perfused thick ascending limb with attached glomerulus preparation dissected from rabbit kidney, intracellular pH (pH(i)) was measured with fluorescence microscopy by using 2',7'-bis-(2-carboxyethyl)-5-(and -6) carboxyfluorescein. NHE activity was assayed by measuring the initial rate of Na(+)-dependent pH(i) recovery from an acid load imposed by prior lumen and bath Na(+) removal. Removal of Na(+) from the bath resulted in a significant, DIDS-insensitive, ethylisopropyl amiloride (EIPA)-inhibitable decrease in pH(i). This basolateral transporter showed very low affinity for EIPA and Hoechst 694 (IC(50) = 9.0 and 247 microM, respectively, consistent with NHE4). The recently reported apical NHE was more sensitive to inhibition by these drugs (IC(50) = 0.86 and 7.6 microM, respectively, consistent with NHE2). Increasing osmolality, a known activator of NHE4, greatly stimulated basolateral NHE. Immunohistochemical studies using antibodies against NHE1-4 peptides demonstrated expression of NHE2 along the apical and NHE4 along the basolateral, membrane, whereas NHE1 and NHE3 were not detected. These results suggest that macula densa cells functionally and immunologically express NHE2 at the apical membrane and NHE4 at the basolateral membrane. These two isoforms likely participate in Na(+) transport, pH(i), and cell volume regulation and may be involved in tubuloglomerular feedback signaling by these cells.

  20. Discovery of selective inhibitors of Glutaminase-2, which inhibit mTORC1, activate autophagy and inhibit proliferation in cancer cells.

    PubMed

    Lee, Yue-Zhi; Yang, Cheng-Wei; Chang, Hsin-Yu; Hsu, Hsing-Yu; Chen, Ih-Shen; Chang, Hsun-Shuo; Lee, Chih-Hao; Lee, Jinq-chyi; Kumar, Chidambaram Ramesh; Qiu, Ya-Qi; Chao, Yu-Sheng; Lee, Shiow-Ju

    2014-08-15

    Glutaminase, which converts glutamine to glutamate, is involved in Warburg effect in cancer cells. Two human glutaminase genes have been identified, GLS (GLS1) and GLS2. Two alternative transcripts arise from each glutaminase gene: first, the kidney isoform (KGA) and glutaminase C (GAC) for GLS; and, second, the liver isoform (LGA) and glutaminase B (GAB) for GLS2. While GLS1 is considered as a cancer therapeutic target, the potential role of GLS2 in cancer remains unclear. Here, we discovered a series of alkyl benzoquinones that preferentially inhibit glutaminase B isoform (GAB, GLS2) rather than the kidney isoform of glutaminase (KGA, GLS1). We identified amino acid residues in an allosteric binding pocket responsible for the selectivity. Treatment with the alkyl benzoquinones decreased intracellular glutaminase activity and glutamate levels. GLS2 inhibition by either alkyl benzoquinones or GLS2 siRNA reduced carcinoma cell proliferation and anchorage-independent colony formation, and induced autophagy via AMPK mediated mTORC1 inhibition. Our findings demonstrate amino acid sequences for selective inhibition of glutaminase isozymes and validate GLS2 as a potential anti-cancer target.