DEFAR - Departamento de Farmácia

URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/530

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Autor: search.filters.author.Martegani, EnzoAssunto: search.filters.subject.Saccharomyces cerevisiae

Resultados da Pesquisa

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    The PLC1 encoded phospholipase C in the yeast Saccharomyces cerevisiae is essential for glucose-induced phosphatidylinositol turnover and activation of plasma membrane H -ATPase.
    (1998) Coccetti, Paola; Tisi, Renata; Martegani, Enzo; Teixeira, Leonardo Souza; Brandão, Rogélio Lopes; Castro, Ieso de Miranda; Thevelein, Johan Maria
    Addition of glucose to glucose-deprived cells of the yeast Saccharomyces cerevisiae triggers rapid turnover of phosphatidylinositol, phosphatidylinositol-phosphate and phosphatidylinositol 4,5-bisphosphate. Glucose stimulation of PI turnover was measured both as an increase in the specific ratio of 32P-labeling and as an increase in the level of diacylglycerol after addition of glucose. Glucose also causes rapid activation of plasma membrane H.-ATPase. We show that in a mutant lacking the PLC1 encoded phospholipase C, both processes were strongly reduced. Compound 48/80, a known inhibitor of mammalian phospholipase C, inhibits both processes. However, activation of the plasma membrane H.- ATPase is only inhibited by concentrations of compound 48/80 that strongly inhibit phospholipid turnover. Growth was inhibited by even lower concentrations. Our data suggest that in yeast cells, glucose triggers through activation of the PLC1 gene product a signaling pathway initiated by phosphatidylinositol turnover and involved in activation of the plasma membrane H.-ATPase.
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    Carbonyl cyanidem - chlorophenylhydrazone induced calcium signaling and activation of plasma membrane H1-ATPase in the yeast Saccharomyces cerevisiae.
    (2008) Pereira, Michele B. P.; Tisi, Renata; Fietto, Luciano Gomes; Cardoso, Anamaria de Souza; França, Mônica M.; Carvalho, Fernanda Machado de; Trópia, Maria José Magalhães; Martegani, Enzo; Castro, Ieso de Miranda; Brandão, Rogélio Lopes
    The plasma membrane H1-ATPase from Saccharomyces cerevisiae is an enzyme that plays a very important role in the yeast physiology. The addition of protonophores, such as 2,4-dinitrophenol (DNP) and carbonyl cyanide m-chlorophenylhydrazone (CCCP), also triggers a clear in vivo activation of this enzyme. Here, we demonstrate that CCCP-induced activation of the plasma membrane H1-ATPase shares some similarities with the sugar-induced activation of the enzyme. Phospholipase C and protein kinase C activities are essential for this activation process while Gpa2p, a G protein involved in the glucose-induced activation of the ATPase, is not required. CCCP also induces a phospholipase Cdependent increase in intracellular calcium. Moreover, we show that the availability of extracellular calcium is required for CCCP stimulation of H1-ATPase, suggesting a possible connection between calcium signaling and activation of ATPase.
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    The involvement of calcium carriers and of the vacuole in the glucose-induced calcium signaling and activation of the plasma membrane H+-ATPase in Saccharomyces cerevisiae cells.
    (2012) Bouillet, Leoneide Érica Maduro; Cardoso, Anamaria de Souza; Perovano, Eduardo; Pereira, R. R.; Ribeiro, Erica Milena de Castro; Trópia, Maria José Magalhães; Fietto, Luciano Gomes; Tisi, Renata; Martegani, Enzo; Castro, Ieso de Miranda; Brandão, Rogélio Lopes
    Previous work from our laboratories demonstrated that the sugar-induced activation of plasma membrane H+-ATPase in Saccharomyces cerevisiae is dependent on calcium metabolism with the contribution of calcium influx from external medium. Our results demonstrate that a glucose-induced calcium (GIC) transporter, a new and still unidentified calcium carrier, sensitive to nifedipine and gadolinium and activated by glucose addition, seems to be partially involved in the glucose-induced activation of the plasma membrane H+-ATPase. On the other hand, the importance of calcium carriers that can release calcium from internal stores was analyzed in glucose-induced calcium signaling and activation of plasma membrane H+-ATPase, in experimental conditions presenting very low external calcium concentrations. Therefore the aim was also to investigate how the vacuole, through the participation of both Ca2+-ATPase Pmc1 and the TRP homologue calcium channel Yvc1 (respectively, encoded by the genes PMC1 and YVC1) contributes to control the intracellular calcium availability and the plasma membrane H+-ATPase activation in response to glucose. In strains presenting a single deletion in YVC1 gene or a double deletion in YVC1 and PMC1 genes, both glucose-induced calcium signaling and activation of the H+-ATPase are nearly abolished. These results suggest that Yvc1 calcium channel is an important component of this signal transduction pathway activated in response to glucose addition. We also found that by a still undefined mechanism Yvc1 activation seems to correlate with the changes in the intracellular level of IP3. Taken together, these data demonstrate that glucose addition to yeast cells exposed to low external calcium concentrations affects calcium uptake and the activity of the vacuolar calcium channel Yvc1, contributing to the occurrence of calcium signaling connected to plasma membrane H+-ATPase activation.
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    Glucose-induced calcium influx in budding yeast involves a novel calcium transport system and can activate calcineurin.
    (2011) Groppi, Silvia; Belotti, Fiorella; Brandão, Rogélio Lopes; Martegani, Enzo; Tisi, Renata
    Glucose addition to glucose-starved Saccharomyces cerevisiae cells triggers a quick and transient influx of calcium from the extracellular environment. In yeast at leasttwodifferent carrier systems were identified: a high affinity system, requiring Cch1 channel, and a low affinity system. Here we report that another calcium transport system exists in yeast, not yet identified, that can substitute the two known systems whenthey are inactivated. This systemwascalled GIC (for Glucose Induced Calcium) system and it is a high affinity calcium transport system, magnesium-sensitive but nickel-resistant. Moreover, GIC transport is sensitive to gadolinium and nifedipine, but it is not sensitive to inhibition by verapamil, which conversely behaves as an agonist on glucose response. GIC transport is fully functional in conditions when calcineurin is active, a serine/threonine specificity phosphatase involved in the regulation of calcium homeostasis and in many other cellular phenomena such as tolerance to high concentrations of Na+ and Li+, response to pheromones and gene transcription regulation. Here it is reported for the first time that calcineurin can also be activated by nutrients: the activation of Crz1 transcription factor by calcineurin was observed in derepressed cells after addition of glucose in the presence of extracellular calcium.