1987 Fiscal Year Final Research Report Summary
Control of yeast cell growth by protein phosphorylation dephosphorylation
| Project/Area Number |
61480058
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
発酵・醸造
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| Research Institution | HIROSHIMA UNIVERSITY |
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Principal Investigator |
TOH-E Akio Department of Fermentation Technology, Faculty of Engineering, 工学部, 教授 (90029249)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Kazuma Department of Fermentation Technology, Faculty of Engineering, 工学部, 助手 (60188290)
YAMASHITA Ichiro Department of Fermentation Technology, Faculty of Engineering, 工学部, 助教授 (20144884)
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| Project Period (FY) |
1986 – 1987
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| Keywords | Saccharomyces cerevisiae / cAMP / protein kinase / cell cycle / BCY1 / ユビキチン |
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| Research Abstract |
Protein kinase is a group of enzymes which regulate various cellular functions by phosphorylating an essential protein(s). Increasing number of protein kinases have been reported these years. Among them, cyclic AMP-dependent protein kinase has been most extensively characterized. The holoenzyme of cAMP-dependent protein kinase is inactive and composed of two catalytic subunits and two regulatory subunits. cAMP binds with the regulatory subunits and then releases active catalytic subunits which, in turn, phosphorylate substrate proteins. Results obtained during the course of this project are summarized as follows.
(1) We have cloned and sequenced the BCY1 gene encoding the regulatory subunit of cAMP-dependent protein kinase. The deduced amino acid sequence indicates that the protein contains the consensus sequence for a phosphoruylation site, RRTS. Amino acid substitutions were induced at the presumed phosphorylation site by oligonucleotide directed mutagenesis. One of the the mutant containing RRNA instead of RRTS showed a cold sensitive phenotype, which can be explained by the idea that the RRNA protein acts as an inhibitor of the catalytic subunit at low temperature.
(2) We have cloned yeast genes which can complement the ppdl defect which presumably fesulted in the defect of protein phoshphatase.
(3) We found that the expression of the polyubiquitin gene (UBI4) is controlled by the cAMP cascade as well as by the heat shock. UBI4 is the first cell cycle related gene which has been shown to be a target of cAMP dependent protein kinase.
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