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Efficient transition to growth on fermentable carbon sources in Saccharomyces cerevisiae requires signaling through the Ras pathway
Author(s) -
Jiang Yu,
Davis Corey,
Broach James R.
Publication year - 1998
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/17.23.6942
Subject(s) - biology , saccharomyces cerevisiae , signal transduction , yeast , carbon source , transition (genetics) , biochemistry , microbiology and biotechnology , genetics , gene
Strains carrying ras2 318S as their sole RAS gene fail to elicit a transient increase in cAMP levels following addition of glucose to starved cells but maintain normal steady‐state levels of cAMP under a variety of growth conditions. Such strains show extended delays in resuming growth following transition from a quiescent state to glucose‐containing growth media, either in emerging from stationary phase or following inoculation as spores onto fresh media. Otherwise, growth of such strains is indistinguishable from that of RAS2 + strains. ras2 318S strains also exhibit a delay in glucose‐stimulated phosphorylation and turnover of fructose‐1,6‐bisphosphatase, a substrate of the cAMP‐dependent protein kinase A (PKA) and a key component of the gluconeogenic branch of the glycolytic pathway. Finally Tpk w strains, which fail to modulate PKA in response to fluctuations in cAMP levels, show the same growth delay phenotypes, as do ras2 318S strains. These observations indicate that the glucose‐induced cAMP spike results in a transient activation of PKA, which is required for efficient transition of yeast cells from a quiescent state to resumption of rapid growth. This represents the first demonstration that yeast cells use the Ras pathway to transmit a signal to effect a biological change in response to an upstream stimulus.