Stress resistance and signal fidelity independent of nuclear MAPK function.
Proc Natl Acad Sci U S A
; 105(34): 12212-7, 2008 Aug 26.
Article
em En
| MEDLINE
| ID: mdl-18719124
ABSTRACT
Elevated external solute stimulates a conserved MAPK cascade that elicits responses that maintain osmotic balance. The yeast high-osmolarity glycerol (HOG) pathway activates Hog1 MAPK (mammalian ortholog p38alpha/SAPKalpha), which enters the nucleus and induces expression of >50 genes, implying that transcriptional up-regulation is necessary to cope with hyperosmotic stress. Contrary to this expectation, we show here that cells lacking the karyopherin required for Hog1 nuclear import or in which Hog1 is anchored at the plasma membrane (or both) can withstand long-term hyperosmotic challenge by ionic and nonionic solutes without exhibiting the normal change in transcriptional program (comparable with hog1Delta cells), as judged by mRNA hybridization and microarray analysis. For such cells to survive hyperosmotic stress, systematic genetic analysis ruled out the need for any Hog1-dependent transcription factor, the Hog1-activated MAPKAP kinases, or ion, glycerol, and water channels. By contrast, enzymes needed for glycerol production were essential for viability. Thus, control of intracellular glycerol formation by Hog1 is critical for maintenance of osmotic balance but not transcriptional induction of any gene.
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Pressão Osmótica
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Transdução de Sinais
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Regulação Fúngica da Expressão Gênica
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Proteínas Quinases Ativadas por Mitógeno
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Proteínas de Saccharomyces cerevisiae
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Ano de publicação:
2008
Tipo de documento:
Article
País de afiliação:
Estados Unidos