PP2A Phosphatase Activity Is Required for Stress and Tor Kinase Regulation of Yeast Stress Response Factor Msn2p

DOI Web Site 被引用文献3件

書誌事項

公開日
2004-10
権利情報
  • https://journals.asm.org/non-commercial-tdm-license
DOI
  • 10.1128/ec.3.5.1261-1271.2004
公開者
American Society for Microbiology

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説明

<jats:title>ABSTRACT</jats:title> <jats:p> In response to stress and nutrient starvation, the <jats:italic>Saccharomyces cerevisiae</jats:italic> transcription factor Msn2p accumulates in the nucleus and activates expression of a broad array of genes. Here, we analyze the role of the Tor (target of rapamycin) signaling pathway in mediating these responses. Inactivation of the Tor pathway component Tap42p using <jats:italic>tap42</jats:italic> (Ts) alleles causes a sustained nuclear localization similar to that after the addition of the Tor kinase inhibitor rapamycin. Effects of Tap42p inactivation and rapamycin addition could be suppressed by deletion of <jats:italic>TIP41</jats:italic> , which encodes a Tap42p-interacting protein. These results support the notion that rapamycin affects Msn2p by inactivating Tap42p function. Tap42p interacts with the catalytic subunit of PP2A (protein phosphatase 2A) and PP2A-like phosphatases. Deletion of either the catalytic or regulatory subunit that forms the PP2A phosphatase complex prevents nuclear accumulation of Msn2p in the <jats:italic>tap42</jats:italic> (Ts) strain and in wild-type strains treated with rapamycin. These results suggest that Tap42p is an inhibitor of PP2A phosphatase, which in turn inhibits nuclear export of Msn2p. Interestingly, PP2A function is also required for nuclear accumulation of Msn2p in response to stresses, such as heat and osmotic shock, as well as nitrogen (but not glucose) starvation. Thus, PP2A and the Tor kinase pathway transduce stress and nitrogen starvation signals to Msn2p. Finally, Msn2p localization is unaffected by conditional loss of 14-3-3 protein function, ruling out the possibility that 14-3-3 proteins act as a scaffold to sequester Msn2p in the cytoplasm. </jats:p>

収録刊行物

  • Eukaryotic Cell

    Eukaryotic Cell 3 (5), 1261-1271, 2004-10

    American Society for Microbiology

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