Effect of Caffeine on Glucose‐Induced Inactivation of Gluconeogenetic Enzymes in <i>Saccharomyces cerevisiae</i>

Tortora, Paolo; Burlini, Nedda; Hanozet, Giorgio M.; Guerritore, A

doi:10.1111/j.1432-1033.1982.tb06825.x

Cited by 41 publications

(22 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Whereas the mutant AM3-4B showed the reported rise in the cyclic nucleotide [ 14,171, in the adenylate cyclase-defective mutant, AM7-1 lD, low and constant levels of CAMP were measured throughout the experiment. Such levels are probably due to contaminating extracellular CAMP present in the growth medium.…”

Section: Resultsmentioning

confidence: 99%

Dependence on cyclic AMP of glucose‐induced inactivation of yeast gluconeogenetic enzymes

et al. 1983

Self Cite

View full text Add to dashboard Cite

show abstract

Section: Resultsmentioning

confidence: 99%

Dependence on cyclic AMP of glucose‐induced inactivation of yeast gluconeogenetic enzymes

et al. 1983

Self Cite

View full text Add to dashboard Cite

show abstract

“…Mannose and raffinose were also effective but gave rather variable results (not shown). Tortora et al (1982) observed that the DNA-stacking drug caffeine inhibits the glucoseinduced increase of the cAMP level and decrease of the fructose-1 ,&bisphosphatase activity in a very similar way. In the course of experiments on the long-term effects of RNA synthesis inhibitors on glucose-induced activation of trehalase, we discovered that the DNA-stacking drugs ethidium bromide, acridine orange and acriflavine caused short-term inhibition of the activation of trehalase.…”

Section: Sugar-induced Trehalase Activationmentioning

confidence: 91%

“…The activity of trehalase (reviewed by Thevelein, 1984a) and fructose-l,6-bisphosphatase (reviewed by Holzer, 1984) is regulated by CAMP-dependent protein phosphorylation. The activity changes of both enzymes are preceded by a rapid, transient increase of the cAMP level (Van der Plaat, 1974;Mazon et al, 1982;Purwin et al, 1982;Tortora et al, 1982;Thevelein, 1984a).…”

Section: Introductionmentioning

confidence: 99%

Cyclic AMP and the Stimulation of Trehalase Activity in the Yeast Saccharomyces cerevisiae by Carbon Sources, Nitrogen Sources and Inhibitors of Protein Synthesis

1985

View full text Add to dashboard Cite

Addition of glucose to acetate-grown cells of Saccharomyces cerevisiae caused a rapid transient increase in the cAMP level followed by a 10-fold, transient increase in the activity of trehalase. Ethidium bromide and acridine analogues inhibited both glucose-induced responses in a similar way, confirming the role of the cAMP signal as the second messenger in the sugar-induced activation of trehalase. When nitrogen sources or protein synthesis inhibitors were added after the transient glucose-induced increase in the trehalase activity, a rapid reactivation of trehalase occurred. In this case, however, there was only a very small increase in the cAMP level, which appeared to be insignificant. When the nitrogen source or the protein synthesis inhibitor was added together with glucose, the trehalase activity remained high for a much longer time also without a significant effect on the cAMP level. When a membrane depolarizing agent was added together with the glucose, both the trehalase activity and the cAMP level remained high. Reversibility experiments in which trehalase was activated to different degrees also showed that for high sugar-induced trehalase activation a high cAMP level is needed, while nitrogen sources stimulate trehalase activity without affecting cAMP levels. In cell extracts, both cAMP and cGMP were able to activate trehalase, the latter however only at 10-fold higher concentrations. The cGMP level in vivo was about 10-fold lower than the cAMP level and was not significantly affected by nitrogen sources or protein synthesis inhibitors. Hence, neither cAMP nor cGMP seem to be involved as the second messenger in the stimulating effect of nitrogen sources and protein synthesis inhibitors on trehalase activity in yeast. Since all other evidence obtained here and before strongly points to regulation of trehalase by a 'cAMP-dependent' protein kinase, we suggest that the presence of a nitrogen source in the growth medium of yeast induces the rapid synthesis of an alternative second messenger able to activate this or another protein kinase.

show abstract

“…Assay O f c A M P Intracellular CAMP concentration was determined with a test kit from Boehringer (Mannheim, FRG) according to the method of Tortora et al [21].…”

Section: Assay Of Glucose Uptakementioning

confidence: 99%

Macromolecular syntheses in the cell cycle mutant cdc25 of budding yeast

Martegani

Vanoni

Baroni

1984

European Journal of Biochemistry

View full text Add to dashboard Cite

A major control point of the cell cycle in Saccharomyces cerevisiae is a G1 event called 'start'. At start a yeast cell integrates external and internal signals and decides to progress toward mitosis or to choose alternative pathways such as sporulation, conjugation etc.cdc25 is a class I1 temperature-sensitive start mutant that blocks at restrictive temperature in GI as round unbudded cells.The arrest of the cell cycle appears to be independent of the carbon and nitrogen sources, and the cell wall of cdc25-arrested cells shows changes similar to those found in cells undergoing entry in to the stationary phase.After a shift to 36 "C the increase in cell number of cdc25 cultures is gradually inhibited. The nuclear division cycle appears to be inhibited immediately after the shift and the percentage of budded cells decreases, while cytoplasmic growth, monitored either as increase of adsorbance at 450 nm or as protein accumulation, continues for many hours leading to a progressive increase of mean cell volume and mean protein content per cell.The stable RNA accumulation instead is immediately inhibited and this is partially due to a 50 inhibition of ribosomal RNA synthesis, while the rate of synthesis of ds-killer RNA is relatively unaffected.These data suggest that the CDC25 gene product could be a part of a mechanism that leads yeast cells to choose between the progression towards DNA replication and cell division or to enter into the stationary phase. This mechanism appears to turn off both rRNA accumulation and cell-cycle progression and to activate differentiative pathways in response to environmental restriction.The molecular basis of the coordination between growth and the nuclear division cycle is far from being understood. For budding yeast Saccharomyces cerevisiae a major control point has been found in G1 and it has been called 'start' [1,2]. At start, a yeast cell integrates much biochemical and environmental information and decides, depending on its genetic background, on a number of alternative pathways : sporulation, conjugation, entrance in stationary phase, or progress towards mitosis [I -41. The traverse of start is required for the beginning of the nuclear division cycle, and in growing cells, a few minutes after the completion of this event, both initiation of DNA synthesis and bud emergence begin [5]. However, many recent papers [3,4,6] have stressed that start is more an area than a point, since different environmental factors block yeast cells at start in physiologically distinct states. Accordingly, the start cdc mutants, i.e. temperature-sensitive mutants that block at a restrictive temperature at or near start, [7] have been divided into class I and class 11 mutants according to their terminal phenotype [6].Class I mutants continue to grow, while bud emergence and DNA replication are blocked, thus resembling alphafactor-treated cells [6]. Moreover, they are able to conjugate at restrictive temperature but not to sporulate if diploid. Class I1 mutants do not grow at restrictive temperature ...

show abstract

Effect of Caffeine on Glucose‐Induced Inactivation of Gluconeogenetic Enzymes in Saccharomyces cerevisiae

Cited by 41 publications

References 38 publications

Dependence on cyclic AMP of glucose‐induced inactivation of yeast gluconeogenetic enzymes

Dependence on cyclic AMP of glucose‐induced inactivation of yeast gluconeogenetic enzymes

Cyclic AMP and the Stimulation of Trehalase Activity in the Yeast Saccharomyces cerevisiae by Carbon Sources, Nitrogen Sources and Inhibitors of Protein Synthesis

Macromolecular syntheses in the cell cycle mutant cdc25 of budding yeast

Contact Info

Product

Resources

About