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[摘要]：In Saccharomyces cerevisiae PKA plays a major role in regulating cell growth, metabolism, and stress resistance. We report that Sch9 regulates PKA directly and SCH9 deletion enhances PKA activity by showing that: (1) Bcy1 predominately localized in the nucleus in glycerol-grown sch9 Delta cells; (2) large part of the catalytic subunits of PKA transferred from the nucleus to the cytoplasm in sch9 Delta cells; (3) higher protein stability of Tpk2 resulted in higher protein level of Tpk2 in sch9 Delta than in wild type cells. Our investigations suggest that Sch9 regulates phosphorylation of Bcy1. We also observed hyper-phosphorylation of Cdc25 in sch9 Delta, in contrast to the tpk2 Delta and tpk2 Delta sch9 Delta mutants, suggesting that feedback inhibition of PKA on Cdc25 is through Tpk2. (C) 2011 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved. |
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