Glucose-dependent, cAMP-mediated ATP efflux from Saccharomyces cerevisiae

Abstract

Extracellular ATP plays an important role in the physiology of multicellular organisms; however, it is unknown whether unicellular organisms such as yeast also release ATP extracellularly. Experiments are described here which show that Saccharomyces cerevisiae releases ATP to the extracellular fluid. This efflux required glucose and the rate was increased dramatically by the proton ionophores nigericin, monensin, carbonyl cyanide mchlorophenylhydrazone and carbonyl cyanide p-(trif 1uoromethoxy)-phenylhydrazone; ATP efflux was also increased by the plasma membrane proton pump inhibitor diethylstilbestrol. The increase in the concentration of extracellular ATP was not due to cell lysis or general disruption of plasma membrane integrity as measured by colony-forming and methylene-bluestaining assays. ATP efflux was strictly correlated with a rise in intracellular CAMP; therefore, the cAMP pathway is likely to be involved in triggering ATP efflux. These results demonstrate that yeast cells release ATP in a regulated manner.1

A Role for Ectophosphatase in Xenobiotic Resistance

“…Some evidence indicates that P-glycoprotein and possibly other ABC proteins can mediate the release of ATP from cells (Abraham et al, 1993;Roman et al, 1997) and that ATP release from yeast cells (Boyum and Guidotti, 1997a) possibly occurs through indirect action of an ABC transporter (Boyum and Guidotti, 1997b). We present data for yeast and plants to indicate that a plant MDR1 homolog may transport ATP and that extracellular ATP concentrations are kept at a low steady state level by ecto-ATPases.…”

“…Figure 1B (top) shows that the steady state extracellular ATP content for the INVSC1 cell line is Ͻ 10 pmol per 3 ϫ 10 6 cells, whereas that for the YMR4 cells is as much as 10 times that amount. Although INVSC differs from YMR4 genotypically, we have used INVSC as a background for comparison with YMR4 because the amount of extracellular ATP seen in the INVSC cells, ‫ف‬ 3 ϫ 10 Ϫ 18 mol per cell, is nearly the same as that previously measured for the parent cell line used to make the YMR4 null, 2.7 ϫ 10 Ϫ 18 mol per cell (Boyum and Guidotti, 1997a). When the YMR4 strain is transformed with MDR1 , the cell line accumulates extracellular ATP more quickly by an order of magnitude than does INVSC ( Figure 1C).…”

“…Although untransformed yeast cells have been shown to release ATP into the extracellular fluid (Boyum and Guidotti, 1997a), presumably through protein-mediated translocation (Boyum and Guidotti, 1997b), our P-glycoprotein transformants had twice the steady state extracellular ATP concentration of wild-type cells, in both the presence and absence of glucose. Previous evidence has indicated that ATP translocation is mediated by ABC proteins in some (A) The steady state concentration of ATP in the extracellular fluid was doubled in wild-type yeast overexpressing the Arabidopsis P-glycoprotein, denoted MDR1.…”

“…It has been suggested that the concentration of extracellular ATP at steady state is kept very low through the action of ectoATPases and ectophosphatases (Boyum and Guidotti, 1997a). To test whether the very low extracellular ATP at steady state in yeast is the result of ATP hydrolysis outside the cell, we examined cell culture ATP accumulation in a yeast strain that is deficient in extracellular phosphatase activity.…”

Glycolytic Synchronization in Yeast Cells via ATP and Other Metabolites: Mathematical Analyses by Two-Dimensional Reaction-Diffusion Models

“…These are signaling molecules contained in all tissues [18]. Other studies also showed that Saccharomyces cerevisiae released ATP to extracellular solutions, suggesting that extracellular ATP, ADP, AMP or adenosine played a role in yeast physiology as intercellular communicators [19] [20].…”