196,637 research outputs found
54esima Biennale di Venezia - Padiglione della Repubblica di San Marino
No full textTitolo del progetto: "Luce In-azione"
Artisti: Dorothee Albrecht, Marco Bravura, Cristian Ceccaroni, Daniela Comani, Ottavio Fabbri, Verdiano Manzi, Patrizia Merendi, Omar Paolucci, Cristina Rotondaro, Lars Teichmann, Thea Tini, Daniela Tonelli, Paola Turroni
Commissario: Leo Marino Morganti.
Curatore: Valerio Pradal
Comitato scientifico e di selezione delle opere:
A. Bassi
F. Cavallari
M. Comoglio
L. Guerrini
M. G. Riva
R. Stih
C. Tartarin
INTRACELLULAR CALCIUM REGULATES THE TYROSINE KINASE RECEPTOR ENCODED BY THE MET ONCOGENE
No full textPrevious work (Gandino, L., Di Renzo, M. F., Giordano, S., Bussolino, F., and Comoglio, P. M. (1990) Oncogene 5, 721-725) has shown that the tyrosine kinase activity of the receptor encoded by the MET protooncogene is negatively modulated by protein kinase C (PKC). We now show that an increase of intracellular Ca2+ has a similar inhibitory effect in vivo, via a PKC-independent mechanism. In GTL-16 cells the p145MET kinase is overexpressed and constitutively phosphorylated on tyrosine. A rapid and reversible decrease of p145MET tyrosine phosphorylation was induced by treatment with the calcium ionophores A23187 or ionomycin. Experiments performed with the ionophores in absence of extracellular calcium showed that a rise in cytoplasmic Ca2+ concentration to 450 nM (due to release from intracellular stores) resulted in a similar effect. These Ca2+ concentrations had no effect on p145MET autophosphorylation in an in vitro kinase assay. This suggests that the effect of Ca2+ on p145MET tyrosine phosphorylation is not direct but may be mediated by Ca2+-activated protein(s). Involvement of Ca2+-dependent tyrosine phosphatases was ruled out by experiments carried out in presence of Na3VO4. In vivo labeling with [P-32]orthophosphate showed that the rise of intracellular Ca2+ induces serine phosphorylation of p145MET on a specific phosphopeptide. This suggests that Ca2+ negatively modulates p145MET kinase through the phosphorylation of a critical serine residue by a Ca2+-activated serine kinase distinct from PKC
To move or not to move? Semaphorin signalling in cell migration
No full textSemaphorins were discovered 11 years ago as molecular cues for axon guidance that are conserved from invertebrates to humans. More than 20 semaphorin genes have been identified in mammals and their protein products are now known to be involved in a range of processes from the guidance of cell migration to the regulation of the immune response, angiogenesis and cancer. Plexins, either alone or in association with neuropilins, constitute high-affinity semaphorin receptors. However, other transmembrane molecules have been implicated in semaphorin receptor complexes, and interactions between plexins and a range of intracellular effectors have been reported. These data indicate that semaphorins might be able to elicit responses through more than one signalling pathway. Interestingly, according to recent findings, the semaphorin-dependent control of cell migration crucially involves integrin-based adhesive structures through which polarized cell-membrane protrusion is coupled to cytoskeletal dynamics. This review focuses on the mechanisms whereby semaphorins are thought to regulate cell migration. © 2004 European Molecular Biology Organization
Dissection of the antigenic determinants expressed on the cell surface of rsv-transformed fibroblasts by monoclonal antibodies.
No full textFusion of P3/X63-Ag8 mouse myeloma cells with splenocytes obtained from mice hyperimmunized with a BHK hamster fibroblast line transformed by an envstrain of Rous sarcoma virus (RSV) resulted in the production of antibody-secreting hybridomas. Seven hybrid clones secreted antibodies binding to RSV-transformed BHK fibroblasts but not to the parental control non-transformed line. The antibodies produced by three of these clones did identify antigenic determinants expressed also on BHK cells transformed by SV40. The antibodies produced by four other clones reacted specifically with cells transformed by RSV but not with cells productively infected by the transformation-defective Rous-associated virus-1; one of these reacted with RSV-transformed hamster cells only, three others identified antigenic determinants common to RSV- transformed cells of different animal species. These data give further support to the idea that RSV-transformed cells express a cell-surface antigen, specific for transformation, the expression of which is controlled by the transforming src gene, and that the specificities carried on it follow a complex pattern, arising from the interaction between antigenic determinants of cellular and viral origin
Habitat modeling in high gradient streams: the meso-scale approach and application
No full textThe study aims to set out a new methodology for habitat modeling in high gradient streams. The methodology is based on the meso-scale approach of the MesoHABSIM simulation system and can support the definition and assessment of environmental flow and habitat restoration measures. Data coming from 40 study sites located within the mountainous areas of the Valle d'Aosta, Piemonte and Liguria regions (NW Italy) are used in the analysis. To adapt MesoHABSIM to high gradient streams, we first modified the data collection strategy to address the challenging conditions of surveys by using GIS and mobile mapping techniques. Secondly, we built the habitat suitability models at a regional scale to enable their transferability among different streams with different morphologies. Thirdly, due to the absence of stream gauges in headwaters, we proposed a possible way to simulate flow time series and, therefore, generate habitat time series. The resulting method is evaluated in terms of time expenditure for field data collection and habitat modeling potentials, and it represents a specific improvement of the MesoHABSIM system for habitat modelling in high gradient streams, where other commonly used methodologies can be unsuitable. Through its application in several study sites, the proposed methodology adapts well to high gradient streams and allows: (1) definition of fish habitat requirements for many streams simultaneously, (2) modeling of habitat variation over a range of discharges, and (3) determination of environmental standards for mountainous watercourses
MONOCLONAL-ANTIBODIES AGAINST CELL-SURFACE ANTIGENS OF ROUS-SARCOMA VIRUS-TRANSFORMED FIBROBLASTS
No full textI passaggi per pesci per il ripristino delle migrazioni dell’ittiofauna lungo i corsi d’acqua: stato dell’arte, criticità e prospettive
No full textA Splicing Variant of the Ron Transcript Induces Constitutive Tyrosine Kinase Activity and Invasive Phenotype
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