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4,4'-(Disulfanedi-yl)dipyridinium chloride triiodide, C10H10N2S2 2+·Cl-·I3 -, (1) was synthesized by reaction of 4,4'-di-pyridyl-disulfide with ICl in a 1:1 molar ratio in di-chloro-methane solution. The structural characterization of 1 by SC-XRD analysis was supported by elemental analysis, FT-IR, and FT-Raman spectroscopic measurements.
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The reactions of 1,3,8,10-tetrakis(4'-fluorophenyl)-4,5,6,7-tetrathiocino[1,2-b:3,4-b']diimidazolyl-2,9-dithione (4) and molecular diiodine afforded spoke adducts with stoichiometries 4·I2 and 4·3I2 , isolated in the compound 4·3I2·xCH2Cl2·(1-x)I2 (x=0.70), and characterized by single-crystal XRD and FT-Raman spectroscopy. The nature of the reaction products was investigated under the prism of theoretical calculations carried out at the DFT level. The structural data, FT-Raman spectroscopy, and quantum mechanical calculations agree in indicating that the introduction of fluorophenyl substituents results in a lowering of the Lewis basicity of this class of bis(thiocarbonyl) donors compared with alkyl-substituted tetrathiocino donors and fluorine allows for extended interactions that are responsible for solid-state crystal packing.
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The reactions of 4,5,6,7-tetrathiocino-[1,2-b:3,4-b']-1,3,8,10-tetrasubstituted-diimidazolyl-2,9-dithiones (R(2),R'(2)-todit; 1: R=R'=Et; 2: R=R'=Ph; 3: R=Et, R'=Ph) with Br(2) exclusively afforded 1:1 and 1:2 "T-shaped" adducts, as established by FT-Raman spectroscopy and single-crystal X-ray diffraction in the case of complex 1·2Br(2). On the other hand, the reactions of compounds 1-3 with molecular I(2) provided charge-transfer (CT) "spoke" adducts, among which the solvated species 3·2I(2)·(1-x)I(2)·xCH(2)Cl(2) (x=0.94) and (3)(2)·7I(2)·xCH(2)Cl(2), (x=0.66) were structurally characterized. The nature of all of the reaction products was elucidated based on elemental analysis and FT-Raman spectroscopy and supported by theoretical calculations at the DFT level.
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This work pertains to the study of exposure to air pollution and noise, of any citizen, in any time of day, within the perimeter of the Polyclinic of Bari. We utilized "dynamic" samplings, in a period of 24 hours, along a walking trail that lasted about 70 minutes, divided on the roads inside the general hospital, performed by voluntary people carrying, by shoulder, a bag containing necessary tools, with their sample heads placed externally in the respiratory area. The values of the environmental survey revealed, particularly, the presence of atmospheric concentrations of PM10 of 63,4 microg/m3 as average value of the whole day and 93 microg/m3 as maximum average value in one hour, far above the limits expected by law for the protection of human health (maximum average value of 50 pg/m3 in 24 hours), almost the whole day and in all areas interested in this study. Also data related to noise showed steady and marked exceeding the limits (average of 68,2 dBA in the morning and 68,0 dBA in the afternoon, versus the limit of 50 dBA by day for hospital areas; average of 65,9 dBA in the night, versus the limit of 40 dBA by night for hospital areas). Instead, a normal situation has been ascertained for the remaining pollutants of the study: the concentrations of carbon monoxide (CO), carbon dioxide (CO2) and ozone (O3) were consistently maintained below the limits for health protection during the whole survey, as well as monitoring for sulfur dioxide (SO2) and volatile organic compounds (VOCs). Air concentration of PM10 and Leq values for noise were, in different times, above the reference limits and surely prejudicial to human health, not only for casual users, employees and students, but especially for the most sensitive patients accessing the hospital; the highest average values were found in periods corresponding to hours of greater intensity of traffic, or rather in the morning and late afternoon, decreasing, however, during the night. It supports the hypothesis that the main anthropogenic source for pollution should be found in the excessive road traffic and transport, as well as data of other urban areas confirm.
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Contaminación del Aire/análisis , Exposición a Riesgos Ambientales/análisis , Ruido , Instituciones de Salud , Humanos , ItaliaRESUMEN
BACKGROUND: Myogenic differentiation involves cell-cycle arrest, activation of the muscle-specific transcriptome, and elongation, alignment and fusion of myoblasts into multinucleated myotubes. This process is controlled by promyogenic transcription factors and regulated by signaling pathways in response to extracellular cues. The p38 mitogen-activated protein kinase (p38 MAPK) pathway promotes the activity of several such transcription factors, including MyoD and MEF2, thereby controlling the muscle-specific transcription program. However, few p38-regulated genes that play a role in the regulation of myogenesis have been identified. METHODS: RNA interference (RNAi), chemical inhibition and immunofluorescence approaches were used to assess the role of drebrin in differentiation of primary mouse myoblasts and C2C12 cells. RESULTS: In a search for p38-regulated genes that promote myogenic differentiation, we identified Dbn1, which encodes the actin-binding protein drebrin. Drebrin is an F-actin side-binding protein that remodels actin to facilitate the change of filopodia into dendritic spines during synaptogenesis in developing neurons. Dbn1 mRNA and protein are induced during differentiation of primary mouse and C2C12 myoblasts, and induction is substantially reduced by the p38 MAPK inhibitor SB203580. Primary myoblasts and C2C12 cells depleted of drebrin by RNAi display reduced levels of myogenin and myosin heavy chain and form multinucleated myotubes very inefficiently. Treatment of myoblasts with BTP2, a small-molecule inhibitor of drebrin, produces a phenotype similar to that produced by knockdown of drebrin, and the inhibitory effects of BTP2 are rescued by expression of a mutant form of drebrin that is unable to bind BTP2. Drebrin in myoblasts is enriched in cellular projections and cell cortices and at regions of cell-cell contact, all sites where F-actin, too, was concentrated. CONCLUSIONS: Our findings reveal that Dbn1 expression is a target of p38 MAPK signaling during myogenesis and that drebrin promotes myoblast differentiation.
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Textile wastewater is difficult to treat as it usually contains considerable amounts of different pollutants, which are often recalcitrant, toxic and inhibitory. Therefore, complex treatment schemes based on the sequence of various steps are usually required for an effective treatment. This explains why textile effluents are often treated in centralized plants and sometimes mixed with municipal wastewater. The adoption of new technologies for on-site treatment, instead, would be optimal, deeply reducing treatment costs. An innovative technology exhibiting several characteristics appropriate for the attainment of such a goal is sequencing batch biofilter granular reactor (SBBGR). To assess the suitability of this technology, two lab-scale reactors were operated, treating mixed municipal-textile wastewater and a pure textile effluent, respectively. Results have demonstrated that mixed wastewater can be successfully treated with very low hydraulic retention times (less than 10 hours). Furthermore, SBBGR shows to be an effective pre-treatment for textile wastewater for discharge into sewer systems. The economic evaluation of the process showed operative costs of 0.10 and 0.19 per m(3) of mixed wastewater and textile wastewater, respectively.
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Reactores Biológicos , Residuos Industriales , Industria Textil , Eliminación de Residuos Líquidos/instrumentación , Eliminación de Residuos Líquidos/métodos , Aguas del Alcantarillado/química , Eliminación de Residuos Líquidos/economía , Contaminantes del Agua/química , Purificación del Agua/economía , Purificación del Agua/instrumentación , Purificación del Agua/métodosRESUMEN
The tetrabutylammonium (TBA(+)) salts of square-planar monoanionic gold complexes of the unsymmetrically substituted Ar,H-edt(2-) 1,2-dithiolene ligands (Ar,H-edt(2-)=arylethylene-1,2-dithiolato; Ar=phenyl (1(-)), 2-naphthyl (2(-)), and 1-pyrenyl (3(-))) were synthesized and characterized by spectroscopic and electrochemical methods and the corresponding neutral species (1, 2, and 3, respectively) were obtained in CH(2)Cl(2) solution at room temperature by diiodine oxidation. The single-crystal X-ray diffraction structural data collected for (TBA(+))(2(-)), supported by DFT theoretical calculations, are consistent with the ene-1,2-dithiolate form of the ligand and the Au(III) oxidation state. All complexes feature intense near-IR absorptions (at about 1.5 microm) in their neutral states and Vis-emitting properties in the 400-550 nm range, the energy of which is controlled by the charge of the complex in the case of the 3(-)/3 couple. The spectroscopic and electrochemical features of 1(x-) and 2(x-) (x=0, 1), both in their cis and trans conformations, were investigated by means of DFT and time-dependent (TD) DFT calculations.
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BACKGROUND: The transcription/export complex is evolutionarily conserved from yeast to man and is required for coupled transcription elongation and nuclear export of mRNAs. FMIP(Fms interacting protein) is a member of the THO (suppressors of the transcriptional defects of hpr1delta by overexpression) complex which is a subcomplex of the transcription/export complex. THO complex (THOC) components are not essential for bulk poly (A)+ RNA export in higher eukaryotes, but for the nuclear export of subset of mRNAs, however, their exact role is still unclear. RESULTS: To study the role of THOC5/Fms interacting protein in vivo, we generated THOC5/Fms interacting protein knockout mice. Since these mice are embryonic lethal, we then generated interferon inducible conditional THOC5/Fms interacting protein knockout mice. After three poly injections all of the mice died within 14 days. No pathological alterations, however, were observed in liver, kidney or heart. Thus we considered the hematopoietic system and found that seven days after poly injection, the number of blood cells in peripheral blood decreased drastically. Investigation of bone marrow cells showed that these became apoptotic within seven days after poly injection. Committed myeloid progenitor cells and cells with long term reconstituting potential were lost from bone marrow within four days after poly injection. Furthermore, infusion of normal bone marrow cells rescued mice from death induced by loss of THOC5/Fms interacting protein. CONCLUSION: THOC5/Fms interacting protein is an essential element in the maintenance of hematopoiesis. Furthermore, mechanistically depletion of THOC5/Fms interacting protein causes the down-regulation of its direct interacting partner, THOC1 which may contribute to altered THO complex function and cell death.
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Proteínas de Unión al ADN/metabolismo , Hematopoyesis/fisiología , Células Madre Hematopoyéticas/fisiología , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas de Unión al ARN/metabolismo , Anemia/metabolismo , Animales , Apoptosis/fisiología , Células Sanguíneas/fisiología , Células de la Médula Ósea/fisiología , Trasplante de Médula Ósea , Supervivencia Celular/fisiología , Hepatocitos/fisiología , Péptidos y Proteínas de Señalización Intracelular/deficiencia , Péptidos y Proteínas de Señalización Intracelular/genética , Leucocitos/fisiología , Leucopenia/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , ARN Mensajero/metabolismoRESUMEN
Primary myelofibrosis (PMF) belongs to the Philadelphia-negative myeloproliferative neoplasms and is a hematological disorder caused by abnormal function of the hematopoietic stem cells. The disease manifests itself with a plethora of alterations, including anemia, splenomegaly and extramedullary hematopoiesis. Its hallmarks are progressive marrow fibrosis and atypical megakaryocytic hyperplasia, two distinctive features used to clinically monitor disease progression. In an attempt to investigate the role of abnormal megakaryocytopoiesis in the pathogenesis of PMF, several transgenic mouse models have been generated. These models are based either on mutations that interfere with the extrinsic (thrombopoietin and its receptor, MPL) and intrinsic (the GATA1 transcription factor) control of normal megakaryocytopoiesis, or on known genetic lesions associated with the human disease. Here we provide an up-to-date review on the insights into the pathobiology of human PMF achieved by studying these animal models, with particular emphasis on results obtained with Gata1(low) mice.
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BACKGROUND: Air pollution leads to increased levels of morbidity and mortality for cardiovascular and respiratory diseases in populations living in urban environments. OBJECTIVES: Our study tested the possibility of using sampling techniques that are typical of industrial hygiene to measure exposure to atmospheric pollutants and using personal samplers for concentrations of certain pollutants to which an ordinary resident of Bari is exposed on a daily basis. METHODS: We monitored dusts (PM10, PM2.5), CO, CO2, humidity, ventilation and noise, by dynamical sampling along a route on foot, bicycle, motorbike and automobile and then compared the results with data provided by fixed stations distributed in the municipality of Bari. RESULTS: By comparing our data with those values provided for by the law, we found out that the concentrations of all pollutants resulted to be higher than 50 microg/m3, with the exception of the measurements carried out along the route by car. The measurements of PM2.5 were, on average, similar to the values of PM10 for the route on foot, but they were totally different for the measurements made along the route by car, bicycle and motorbike. Moreover, comparing our data with those obtained from the municipal network of fixed stations, we found that results provided by our measurements were higher for PM10. CONCLUSIONS: Considering that compliance with the limits set by law refers to average values over 24 hours, we can conclude that those hours in which pollutant concentration reaches a risk level shall be considered especially regarding groups of people with respiratory disorders.
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Contaminantes Atmosféricos/análisis , Contaminación del Aire/estadística & datos numéricos , Exposición a Riesgos Ambientales/estadística & datos numéricos , Contaminación del Aire/legislación & jurisprudencia , Ciclismo , Dióxido de Carbono/análisis , Monóxido de Carbono/análisis , Polvo , Exposición a Riesgos Ambientales/legislación & jurisprudencia , Humanos , Humedad , Italia , Concentración Máxima Admisible , Vehículos a Motor , Ruido , Temperatura , Factores de Tiempo , Transportes , Salud Urbana , CaminataRESUMEN
The reaction between the coordinatively unsaturated phosphonodithioato complex [Ni(MeOpdt)2] (1) [MeOpdt = (MeO)(4-MeOC(6)H(4))PS2-] and tptz [2,4,6-tris(2-pyridyl)-1,3,5-triazine] has been investigated. Spectrophotometric and conductometric titrations showed the formation of a neutral and an ionic species, i.e. [Ni(MeOdtp)2(tptz)] (2) and [Ni(tptz)2](MeOdtp)2 (3), in correspondence to 1 : 1 and 2 : 1 tptz : ratios, respectively. XRD studies confirmed the formation of both complexes isolated in the compounds 2.MeOH and 3.4H(2)O. In the neutral complex 2 the central Ni(II) ion features a distorted octahedral coordination, achieved through three N-atoms of tptz and three S-atoms belonging to two MeOpdt anions, one of which unexpectedly acts as a monodentate S-donor. In 3.4H(2)O, the two phosphonodithioato anions are non-coordinating and counterbalance the charge of the [Ni(tptz)2](2+) distorted octahedral complex. From the reaction 2 of with I2 and Br2, crystals of [Ni(tptz)2](I3)2 (5) and [Ni(tptz)Br(micro-Br)]2 (6) have been obtained. The dinuclear complex 6 features a structure showing tubular canals with openings of about 6 x 6 A.
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The 3 centre-4 electrons (3c-4e) and the donor/acceptor or charge-transfer models for the description of the chemical bond in linear three-body systems, such as I(3) (-) and related electron-rich (22 shell electrons) systems, are comparatively discussed on the grounds of structural data from a search of the Cambridge Structural Database (CSD). Both models account for a total bond order of 1 in these systems, and while the former fits better symmetric systems, the latter describes better strongly asymmetric situations. The 3c-4e MO scheme shows that any linear system formed by three aligned closed-shell species (24 shell electrons overall) has reason to exist provided that two electrons are removed from it to afford a 22 shell electrons three-body system: all combinations of three closed-shell halides and/or chalcogenides are considered here. A survey of the literature shows that most of these three-body systems exist. With some exceptions, their structural features vary continuously from the symmetric situation showing two equal bonds to very asymmetric situations in which one bond approaches to the value corresponding to a single bond and the second one to the sum of the van der Waals radii of the involved atoms. This indicates that the potential energy surface of these three-body systems is fairly flat, and that the chemical surrounding of the chalcogen/halogen atoms can play an important role in freezing different structural situations; this is well documented for the I(3) (-) anion. The existence of correlations between the two bond distances and more importantly the linearity observed for all these systems, independently on the degree of their asymmetry, support the state of hypervalency of the central atom.
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The chemical bond and structural features for the most important classes of solid products obtained by reacting chalcogen donors with dihalogens and interhalogens are reviewed. Particular attention is paid to the information the FT-Raman spectroscopy can confidently give about each structural motif considered in the absence of X-ray structural analyses.
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We report the first examples of metal dithiolenes belonging to the class [M(R-dmet)(2)] [R-dmet = formally monoreduced N-substituted thiazolidine-2,4,5-trithione; R = Et, M = Ni (1), Pd (2), Pt (3)]. A comparative spectroscopic, electrochemical, and density functional theory theoretical investigation indicates that [M(R-dmet)(2)] complexes show features intermediate between those of the dithiolenes belonging to the previously reported classes [M(R,R'-timdt)(2)] and [M(dmit)(2)] (R,R'-timdt = formally monoreduced N,N'-disubstituted imidazolidine-2,4,5-trithione; dmit = 2-thioxo-1,3-dithiole-4,5-dithiolato). UV-vis-near-IR spectroscopy and cyclic voltammetry/differential pulsed voltammetry measurements performed on 1 and 3 proved that the new dithiolenes are stable as neutral, monoanionic, and bianionic species and feature a near-IR electrochromic absorption falling at about 1000 and 1250 nm for neutral and monoanionic species, respectively.
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Recently, evidence has been accumulating that inositol and phosphatidylinositol polyphosphate play important roles in a variety of signal transduction systems including membrane traffic, actin cytoskeleton rearrangement and cell motility. In this paper, we show for the first time that the SH2-domain-containing inositol 5-phosphatase (SHIP)-2 binds directly to the hepatocyte growth factor (HGF/SF) receptor, c-Met, via phosphotyrosine 1356. HGF induces the breakdown of cell junctions and the dispersion of colonies of epithelial cells including MDCK cells. Whereas only few lamellipodia are observed in MDCK cells 2 min after stimulation with HGF, both SHIP-2- and SHIP-1-overexpressing cells form large, broad lamellipodia. The number of lamellipodia is 2-4-fold greater than that of mock-transfected MDCK cells in the same time period and SHIP is found to colocalize with actin at the leading edge. Furthermore, overexpression of a catalytic inactive mutant of SHIP-2 suppresses HGF-potentiated cell scattering and cell spreading, although these mutant-expressing cells form enhanced number of lamellipodia 2 min after HGF stimulation. Interestingly, cells expressing a mutant lacking the proline-rich domain of SHIP-2 at the C-terminal form few lamellipodia, but still spread and scatter upon stimulation with HGF at a reduced rate. These data suggest that phosphatase activity is required for HGF-mediated cell spreading and scattering but not for alteration of lamellipodium formation, while the proline-rich region influences lamellipodium formation. Furthermore, treatment with 10 microM of phosphatidylinositol 3 (PI3) kinase inhibitor, LY294002, abrogates HGF-induced cell scattering of SHIP-2-overexpressing cells but not parental HEK293 cells, suggesting that a balance between PI3 kinase and SHIP is important for cell motility.
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Movimiento Celular/genética , Factor de Crecimiento de Hepatocito/farmacología , Monoéster Fosfórico Hidrolasas/genética , Proteínas Proto-Oncogénicas c-met/metabolismo , Animales , Técnicas de Cultivo de Célula , Perros , Humanos , Riñón/citología , Fosfatidilinositol 3-Quinasas/farmacología , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatasas , Monoéster Fosfórico Hidrolasas/metabolismo , Proteínas Proto-Oncogénicas c-met/farmacología , Seudópodos/genética , Transducción de Señal , Tirosina/metabolismoRESUMEN
The p75 neurotrophin receptor (p75NTR) has dual functions in cell survival and cell death but its intracellular signalling pathways are not understood. Here we describe that in rat brain and in pervanadate-stimulated PCNA and HEK293 cells p75NTR is phosphorylated at a single tyrosine residue within the cytosolic C-terminus. Phosphorylated tyrosine 308 constitutes a binding site for the ubiquitin ligase c-Cbl. This interaction is a prerequisite for ubiquitination of p75NTR. Our data suggest a c-Cbl-dependent ubiquitination of p75NTR involved in the regulation of p75NTR signalling.
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Proteínas Proto-Oncogénicas/metabolismo , Receptores de Factor de Crecimiento Nervioso/metabolismo , Transducción de Señal/fisiología , Tirosina/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Ubiquitina/metabolismo , Secuencia de Aminoácidos/fisiología , Sitios de Unión/efectos de los fármacos , Sitios de Unión/fisiología , Línea Celular , Humanos , Fosforilación , Unión Proteica/efectos de los fármacos , Unión Proteica/fisiología , Proteínas Proto-Oncogénicas c-cbl , Receptor de Factor de Crecimiento Nervioso , Vanadatos/farmacologíaRESUMEN
Macrophage colony-stimulating factor (M-CSF or CSF-1) and its cognate receptor, the tyrosine kinase c-fms, are essential for monocyte and macrophage development. We have recently identified an Fms-interacting protein (FMIP) that binds transiently to the cytoplasmic domain of activated Fms molecules and is phosphorylated on tyrosine by Fms tyrosine kinase. FMIP is a substrate not only for Fms but also for protein kinase C (PKC). Mutagenesis reveals that this occurs on serines 5 and 6. Adjacent to these sites is a nuclear localization signal (NLS). We show that this NLS is essential for the predominantly nuclear localization of FMIP. Generation of phosphomimetic substitutions on serine residues 5 and 6 confirms that PKC-mediated phosphorylation on this site leads to translocation of FMIP to the cytosol. Furthermore, the mutant FMIP (FMIPSS5,6AA) was detected abundantly in the nucleus even in the presence of activated PKCalpha. Wild-type FMIP and FMIPSS5,6AA inhibited M-CSF-mediated survival signaling, while FMIPSS5,6EE-expressing cells survived and differentiated into macrophages more efficiently than wild-type cells in the presence of M-CSF or TPA. We conclude M-CSF-mediated activation of PKCalpha can potentiate FMIP action to initiate survival/differentiation signaling.
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Proteínas Portadoras/metabolismo , Péptidos y Proteínas de Señalización Intracelular , Factor Estimulante de Colonias de Macrófagos/fisiología , Proteína Quinasa C/metabolismo , Receptor de Factor Estimulante de Colonias de Macrófagos/metabolismo , Fracciones Subcelulares/metabolismo , Animales , Diferenciación Celular , Activación Enzimática , Etiquetado Corte-Fin in Situ , Ratones , Células 3T3 NIH , FosforilaciónRESUMEN
The reaction of the neutral dithiolene [Pd(Et2timdt)2] (Et2timdt = formally monoreduced diethylimidazolidine-2,4,5-trithione) with an excess of Br2 yielded few crystals of [1(Et) x 2Br](2+)(Br-)2(Br2)3 as a by-product (1(Et) = 4,5,9,10-tetrathiocino-[1,2-b:5,6-b']-1,3,6,8-tetraethyl-diimidazolyl-2,7-dithione); X-ray diffraction analysis showed that this compound represents the first example of a polybromide 2D-network templated by [1(Et) x 2Br](+2) dications, and featuring all the Br-Br distances shorter than those found in solid state bromine.
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Hepatocyte growth factor (HGF) induces the breakdown of cell junction and the dispersion of colonies of epithelial cells, providing a model system for the investigation of the molecular mechanisms of one of the important aspects of tumorogenesis. We have previously reported that the SH2-domain-containing inositol 5'phosphatase (SHIP)-1 binds to c-Met, and potentiated HGF-mediated branching tubulogenesis. In this study, we describe the establishment of MDCK cell lines which express MycHis-tagged SHIP-1 at different levels. Expression of SHIP-1 in MDCK cells at a high level resulted in cell morphology characteristic of an epithelial-mesenchymal like transition; cells lost cortical actin, developed actin stress fibers and gained spontaneous motility without treatment of HGF. When the level of MycHis-tagged SHIP-expression was relatively low, transfectants partially lost cortical actin and phalloidin stained puncta appeared at cell-cell junctions even in the absence of HGF. The treatment of MAP kinase inhibitor, PD98059, did not influence SHIP-1 mediated alteration of adherens-junction of MDCK cells, while, phosphatidylinositol 3 (PI 3)- kinase inhibitor, LY294002, drastically reduced SHIP-1 mediated phenotype. Furthermore, expression of a mutant SHIP-1 lacking catalytic activity in MDCK cells did not alter the cortical actin distribution and HGF-mediated MAP and Akt kinase-phosphorylation, but suppressed HGF induced cell dispersion, suggesting that phosphatase activity is important for cytoskeleton rearrangement and cell dispersion.
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Uniones Adherentes/enzimología , Células Epiteliales/ultraestructura , Monoéster Fosfórico Hidrolasas/metabolismo , Uniones Adherentes/metabolismo , Uniones Adherentes/ultraestructura , Animales , Línea Celular , Movimiento Celular , Cromonas/farmacología , Perros , Inhibidores Enzimáticos/farmacología , Células Epiteliales/enzimología , Células Epiteliales/metabolismo , Factor de Crecimiento de Hepatocito/farmacología , Microscopía Fluorescente , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Morfolinas/farmacología , Mutación , Faloidina/química , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatasas , Inhibidores de las Quinasa Fosfoinosítidos-3 , Monoéster Fosfórico Hidrolasas/química , Monoéster Fosfórico Hidrolasas/genética , Fosforilación , Fibras de Estrés/ultraestructura , Transfección , Dominios Homologos srcRESUMEN
The receptor for the macrophage colony-stimulating factor (CSF-1, also termed M-CSF), the tyrosine kinase c-Fms, was originally determined to be the oncogene product of the McDonough strain of feline sarcoma virus, v-Fms. The structural difference between c-Fms and v-Fms amounts to only five point mutations in the extracellular domain, two mutations in the cytoplasmic domain, and the replacement of 50 amino acids by 14 unrelated amino acids at the C-terminal tail. Here, we have identified c-Cbl as the direct binding partner for c-Fms. c-Cbl binds to phosphotyrosine residue 977 at the C-terminal end of feline c-Fms, which is absent in v-Fms. The replacement of the C-terminal end of v-Fms by the corresponding part of c-Fms (vc-Fms) restored the binding potential. As a result, vc-Fms reduced the transforming potency of v-Fms. The overexpression of Cbl did not influence the v-Fms-transformed phenotype, although c-Cbl forms a complex with v-Fms indirectly. In contrast, the expression of Cbl drastically reduced the vc-Fms-transformed phenotype and the activation of Erk and enhanced Fms ubiquitination via phosphotyrosine residue 977. Furthermore, the replacement of tyrosine 977 into phenylalanine in feline c-Fms and vc-Fms reduced the Cbl-dependent ubiquitination. These data suggest that an indirect association of c-Cbl via multimeric complex induced a different signaling pathway from the pathway induced by c-Cbl direct interaction.