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Glucose‐stimulated cAMP increase may be mediated by intracellular acidification in Saccharomyces cerevisiae
Author(s) -
Caspani Giorgio,
Tortora Paolo,
Hanozet Giorgio M.,
Guerritore Andrea
Publication year - 1985
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(85)81342-9
Subject(s) - protonophore , depolarization , intracellular , extracellular , intracellular ph , chemistry , saccharomyces cerevisiae , biophysics , valinomycin , biochemistry , membrane potential , biology , yeast
It has been reported that addition of glucose to cells of Saccharomyces cerevisiae grown on a sugar‐free medium causes a peak of intracellular cAMP levels. Also, it has been proposed that this effect might be mediated by plasma membrane depolarization. However, here, we observed a hyperpolarizing effect of glucose in S. cerevisiae and, in addition, no change in cAMP levels when depolarization was induced by valinomycin in the presence of K + . In contrast, treatments that induced a rapid intracellular acidification such as addition of the protonophore carbonyl cyanide p ‐trifluoromethoxyphenylhydrazone at pH 5.5 but not at pH 8.0, extracellular pH shift from 8.5 to 3.5, and glucose itself, also increased the cyclic nucleotide. Thus, our data strongly support the hypothesis that intracellular acidification mediates the effect of glucose on cAMP levels.