Regulation of Snf1 Protein Kinase in Response to Environmental Stress

The Saccharomyces cerevisiae Snf1 protein kinase, a member of the Snf1/AMPK (AMP-activated protein kinase) family, has important roles in metabolic control, particularly in response to nutrient stress. Here we have addressed the role of Snf1 in responses to other environmental stresses. Exposure of...

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Bibliographic Details
Published in:The Journal of biological chemistry 2007-06, Vol.282 (23), p.16838-16845
Main Authors: Hong, Seung-Pyo, Carlson, Marian
Format: Article
Language:English
Subjects:
Catalysis
Enzyme Activation
Hot Temperature
Hydrogen-Ion Concentration
Oxidative Stress
Phosphorylation
Protein Transport
Protein-Serine-Threonine Kinases - chemistry
Protein-Serine-Threonine Kinases - metabolism
Protein-Serine-Threonine Kinases - physiology
Saccharomyces cerevisiae
Saccharomyces cerevisiae - enzymology
Subcellular Fractions - enzymology
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Summary:The Saccharomyces cerevisiae Snf1 protein kinase, a member of the Snf1/AMPK (AMP-activated protein kinase) family, has important roles in metabolic control, particularly in response to nutrient stress. Here we have addressed the role of Snf1 in responses to other environmental stresses. Exposure of cells to sodium ion stress, alkaline pH, or oxidative stress caused an increase in Snf1 catalytic activity and phosphorylation of Thr-210 in the activation loop, whereas treatment with sorbitol or heat shock did not. Inhibition of respiratory metabolism by addition of antimycin A to cells also increased Snf1 activity. Analysis of mutants indicated that the kinases Sak1, Tos3, and Elm1, which activate Snf1 in response to glucose limitation, are also required under other stress conditions. Each kinase sufficed for activation in response to stress, but Sak1 had the major role. In sak1Δ tos3Δ elm1Δ cells expressing mammalian Ca2+/calmodulin-dependent protein kinase kinase α, Snf1 was activated by both sodium ion and alkaline stress, suggesting that stress signals regulate Snf1 activity by a mechanism that is independent of the upstream kinase. Finally, we showed that Snf1 protein kinase is regulated differently during adaptation of cells to NaCl and alkaline pH with respect to both temporal regulation of activation and subcellular localization. Snf1 protein kinase becomes enriched in the nucleus in response to alkaline pH but not salt stress. Such differences could contribute to specificity of the stress responses.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.M700146200