Abstract
The Saccharomyces cerevisiae CDC25 gene encodes a guanine nucleotide exchange factor for Ras proteins whose catalytic domain is highly homologous to Ras-guanine nucleotide exchange factors from higher eukaryotes. In this study, glucose-induced Ras activation and cAMP response were investigated in mutants lacking the N-terminal domain of Cdc25 or where the entire CDC25 coding sequence was substituted by an expression cassette for a mammalian guanine nucleotide exchange factor catalytic domain. Our results suggest that an unregulated, low Ras guanine nucleotide exchange factor activity allows a normal glucose-induced cAMP signal that appears to be mediated mainly by the Gpr1/Gpa2 system, but it was not enough to sustain the glucose-induced increase of Ras2-GTP normally observed in a wild-type strain.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Cell Cycle Proteins / genetics
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Cell Cycle Proteins / physiology*
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Cyclic AMP / metabolism
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Fungal Proteins / genetics
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Fungal Proteins / physiology*
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GTP-Binding Protein alpha Subunits / physiology
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Gene Deletion
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Gene Expression Regulation, Fungal*
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Glucose / metabolism*
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Mutagenesis, Insertional
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Receptors, G-Protein-Coupled / physiology
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Saccharomyces cerevisiae / genetics
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Saccharomyces cerevisiae / physiology*
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Saccharomyces cerevisiae Proteins / metabolism*
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Saccharomyces cerevisiae Proteins / physiology
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Sequence Deletion
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ras Proteins / metabolism*
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ras-GRF1 / genetics
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ras-GRF1 / physiology*
Substances
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CDC25 protein, S cerevisiae
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Cell Cycle Proteins
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Fungal Proteins
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GPR1 protein, S cerevisiae
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GTP-Binding Protein alpha Subunits
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Receptors, G-Protein-Coupled
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Saccharomyces cerevisiae Proteins
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ras-GRF1
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Cyclic AMP
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Gpa2 protein, S cerevisiae
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RAS2 protein, S cerevisiae
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ras Proteins
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Glucose