RESUMO
Mitogen-activated protein kinase (MAPK) cascade is a ubiquitous signaling module that transmits extracellular stimuli through the cytoplasm to the nucleus. In baker's yeast external high osmolarity activates high osmolarity glycerol (HOG) MAPK pathway which consists of two upstream branches (SHO1 and SLN1) and common downstream elements Pbs2p MAPKK and Hog1p MAPK. Activation of this pathway causes rapid nuclear accumulation of Hog1p, essentially leading to the expression of target genes. Previously we have isolated a PBS2 homologue (DPBS2) from osmo-tolerant and salt-tolerant yeast Debaryomyces hansenii that partially complemented pbs2 mutation in Saccharomyces cerevisiae. Here we show that by replacing C-terminal region of Dpbs2p with the homologous region of Pbs2p we could abrogate partial complementation exhibited by Dpbs2p and this was achieved due to increase in nuclear translocation of Hog1p. Thus, our result showed that in HOG pathway, MAPKK has important role in nuclear translocation of Hog1p.
Assuntos
Transporte Ativo do Núcleo Celular/fisiologia , Núcleo Celular/metabolismo , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Proteínas Recombinantes/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/enzimologia , Saccharomycetales/enzimologia , Transporte Ativo do Núcleo Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Quinases de Proteína Quinase Ativadas por Mitógeno/genética , Proteínas Quinases Ativadas por Mitógeno/genética , Pressão Osmótica/efeitos dos fármacos , Estrutura Terciária de Proteína , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomycetales/efeitos dos fármacos , Saccharomycetales/genética , Transdução de Sinais/fisiologia , Cloreto de Sódio/farmacologia , Relação Estrutura-Atividade , Equilíbrio Hidroeletrolítico/efeitos dos fármacos , Equilíbrio Hidroeletrolítico/fisiologiaRESUMO
Analysis of seventeen yeast strains by 13C-NMR spectroscopy has confirmed the significance of glycerol as the sole osmoregulatory solute under salt-stressed conditions, and has shown arabitol to be present in most of the osmotolerant species. Ribitol was detected in some species, including Debaryomyces hansenii, although ribitol accumulation did not correlate with the osmotic pressure of the medium. Relative amounts of arabitol and ribitol decreased in relation to glycerol when the external osmotic pressure was increased. Trehalose was present during exponential growth of some species.