The large N-terminal domain of Cdc25 protein of the yeast Saccharomyces cerevisiae is required for glucose-induced Ras2 activation.
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.
Paiardi
Chiara
C
Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy.
Belotti
Fiorella
F
Colombo
Sonia
S
Tisi
Rentata
R
Martegani
Enzo
E
D018797:Cell Cycle Proteins / Q000235:genetics / Q000502:physiology*; D000242:Cyclic AMP / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology*; D044385:GTP-Binding Protein alpha Subunits / Q000502:physiology; D017353:Gene Deletion; D015966:Gene Expression Regulation, Fungal; D005947:Glucose / Q000378:metabolism*; D016254:Mutagenesis, Insertional; D043562:Receptors, G-Protein-Coupled / Q000502:physiology; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism* / Q000502:physiology; D017384:Sequence Deletion; D018631:ras Proteins / Q000378:metabolism*; D020666:ras-GRF1 / Q000235:genetics / Q000502:physiology*
C542351:CDC25 protein, S cerevisiae; D018797:Cell Cycle Proteins; D005656:Fungal Proteins; C109334:GPR1 protein, S cerevisiae; D044385:GTP-Binding Protein alpha Subunits; D043562:Receptors, G-Protein-Coupled; D029701:Saccharomyces cerevisiae Proteins; D020666:ras-GRF1; D000242:Cyclic AMP; C083907:Gpa2 protein, S cerevisiae; C489015:RAS2 protein, S cerevisiae; D018631:ras Proteins; D005947:Glucose