scholarly journals Initiation of meiosis and sporulation in Saccharomyces cerevisiae does not require a decrease in cyclic AMP.

1987 ◽  
Vol 7 (6) ◽  
pp. 2141-2147 ◽  
Author(s):  
Z Olempska-Beer ◽  
E Freese
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Cyclic Amp ◽  
Phosphodiesterase Inhibitor ◽  
Intracellular Camp ◽  
Glucose Medium ◽  
Camp Concentration ◽  
Ishikawa Cell ◽  
Camp Phosphodiesterase ◽  
Low Level

Meiosis and sporulation of Saccharomyces cerevisiae are initiated in a guanine auxotroph by guanine deprivation (E. Bautz Freese, Z. Olempska-Beer, A. Hartig, and E. Freese, Dev. Biol. 102:438-451, 1984). We used this condition to examine a hypothesis (K. Matsumoto, I. Uno, and T. Ishikawa, Cell 32:417-423, 1983) that initiation of meiosis requires a low level of cAMP. We found that, after guanine deprivation, the intracellular concentration of cAMP transiently decreased not more than 20% and not at all if the cAMP phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX) was added to the medium. Under these conditions, at least 76% of the cells sporulated in the absence of IBMX, and almost 100% sporulated in its presence. The sporulating cells continually excreted cAMP and utilized the gluconeogenic carbon source. The cells failed to sporulate efficiently and to form four-spored asci if simultaneously deprived of guanine and carbon. After guanine deprivation in glucose medium, sporulation remained suppressed and intracellular cAMP was unchanged. We conclude that, under conditions of guanine starvation, cAMP deficiency is not required for initiation of meiosis and sporulation, cAMP is produced in excess and excreted to the medium, the cells sporulate better if the cAMP concentration is increased by addition of IBMX, the cells require a gluconeogenic carbon source for complete and efficient sporulation, and suppression of sporulation by glucose is not mediated by cAMP.

Initiation of meiosis and sporulation in Saccharomyces cerevisiae does not require a decrease in cyclic AMP

1987 ◽  
Vol 7 (6) ◽  
pp. 2141-2147
Author(s):  
Z Olempska-Beer ◽  
E Freese
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Carbon Source ◽  
Cyclic Amp ◽  
Phosphodiesterase Inhibitor ◽  
Intracellular Camp ◽  
Glucose Medium ◽  
Camp Concentration ◽  
Ishikawa Cell ◽  
Camp Phosphodiesterase ◽  
Low Level

Meiosis and sporulation of Saccharomyces cerevisiae are initiated in a guanine auxotroph by guanine deprivation (E. Bautz Freese, Z. Olempska-Beer, A. Hartig, and E. Freese, Dev. Biol. 102:438-451, 1984). We used this condition to examine a hypothesis (K. Matsumoto, I. Uno, and T. Ishikawa, Cell 32:417-423, 1983) that initiation of meiosis requires a low level of cAMP. We found that, after guanine deprivation, the intracellular concentration of cAMP transiently decreased not more than 20% and not at all if the cAMP phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX) was added to the medium. Under these conditions, at least 76% of the cells sporulated in the absence of IBMX, and almost 100% sporulated in its presence. The sporulating cells continually excreted cAMP and utilized the gluconeogenic carbon source. The cells failed to sporulate efficiently and to form four-spored asci if simultaneously deprived of guanine and carbon. After guanine deprivation in glucose medium, sporulation remained suppressed and intracellular cAMP was unchanged. We conclude that, under conditions of guanine starvation, cAMP deficiency is not required for initiation of meiosis and sporulation, cAMP is produced in excess and excreted to the medium, the cells sporulate better if the cAMP concentration is increased by addition of IBMX, the cells require a gluconeogenic carbon source for complete and efficient sporulation, and suppression of sporulation by glucose is not mediated by cAMP.

Cloning and characterization of the low-affinity cyclic AMP phosphodiesterase gene of Saccharomyces cerevisiae

1987 ◽  
Vol 7 (10) ◽  
pp. 3629-3636
Author(s):  
J Nikawa ◽  
P Sass ◽  
M Wigler
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cyclic Amp ◽  
Copy Number ◽  
Growth Arrest ◽  
Yeast Cells ◽  
Phosphodiesterase Activity ◽  
Camp Phosphodiesterase ◽  
High Affinity ◽  
Cyclic Amp Phosphodiesterase

Saccharomyces cerevisiae contains two genes which encode cyclic AMP (cAMP) phosphodiesterase. We previously isolated and characterized PDE2, which encodes a high-affinity cAMP phosphodiesterase. We have now isolated the PDE1 gene of S. cerevisiae, which encodes a low-affinity cAMP phosphodiesterase. These two genes represent highly divergent branches in the evolution of phosphodiesterases. High-copy-number plasmids containing either PDE1 or PDE2 can reverse the growth arrest defects of yeast cells carrying the RAS2(Val-19) mutation. PDE1 and PDE2 appear to account for the aggregate cAMP phosphodiesterase activity of S. cerevisiae. Disruption of both PDE genes results in a phenotype which resembles that induced by the RAS2(Val-19) mutation. pde1- pde2- ras1- ras2- cells are viable.

scholarly journals Small-molecule allosteric activators of PDE4 long form cyclic AMP phosphodiesterases

2019 ◽  
Vol 116 (27) ◽  
pp. 13320-13329 ◽  
Author(s):  
Faisa Omar ◽  
Jane E. Findlay ◽  
Gemma Carfray ◽  
Robert W. Allcock ◽  
Zhong Jiang ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Small Molecule ◽  
Protein Complexes ◽  
Cyst Formation ◽  
Camp Signaling ◽  
Intracellular Camp ◽  
Camp Phosphodiesterase ◽  
Cellular Processes ◽  
Small Molecule Compound ◽  
Autosomal Dominant Polycystic Kidney

Cyclic AMP (cAMP) phosphodiesterase-4 (PDE4) enzymes degrade cAMP and underpin the compartmentalization of cAMP signaling through their targeting to particular protein complexes and intracellular locales. We describe the discovery and characterization of a small-molecule compound that allosterically activates PDE4 long isoforms. This PDE4-specific activator displays reversible, noncompetitive kinetics of activation (increased Vmax with unchanged Km), phenocopies the ability of protein kinase A (PKA) to activate PDE4 long isoforms endogenously, and requires a dimeric enzyme assembly, as adopted by long, but not by short (monomeric), PDE4 isoforms. Abnormally elevated levels of cAMP provide a critical driver of the underpinning molecular pathology of autosomal dominant polycystic kidney disease (ADPKD) by promoting cyst formation that, ultimately, culminates in renal failure. Using both animal and human cell models of ADPKD, including ADPKD patient-derived primary cell cultures, we demonstrate that treatment with the prototypical PDE4 activator compound lowers intracellular cAMP levels, restrains cAMP-mediated signaling events, and profoundly inhibits cyst formation. PDE4 activator compounds thus have potential as therapeutics for treating disease driven by elevated cAMP signaling as well as providing a tool for evaluating the action of long PDE4 isoforms in regulating cAMP-mediated cellular processes.

scholarly journals Control of cyclic AMP concentration in bovine endometrial stromal cells by arachidonic acid

Reproduction ◽  
2007 ◽  
Vol 133 (5) ◽  
pp. 1017-1026 ◽  
Author(s):  
Z Cheng ◽  
E L Sheldrick ◽  
E Marshall ◽  
D C Wathes ◽  
D R E Abayasekara ◽  
...  
Keyword(s):  
Arachidonic Acid ◽  
Cyclic Amp ◽  
Stromal Cells ◽  
Inhibitory Effect ◽  
Intracellular Camp ◽  
Dibutyryl Camp ◽  
Camp Concentration ◽  
Endometrial Stromal Cells ◽  
Kinase C ◽  
Intracellular Camp Concentration

Second messenger signalling through cyclic AMP (cAMP) plays an important role in the response of the endometrium to prostaglandin (PG) E2during early pregnancy. Arachidonic acid, which is a by-product of the luteolytic cascade in ruminants, is a potential paracrine signal from the epithelium to the stroma. We investigated the effects of arachidonic acid on the response of the stroma to PGE2. cAMP was measured in bovine endometrial stromal cells treated with agents known to activate or inhibit adenylyl cyclase, protein kinase C (PKC) or phosphodiesterase (PDE). PGE2increased the intracellular cAMP concentration within 10 min, and this effect was attenuated by arachidonic acid and the PKC activator, 4β-phorbol myristate acetate (PMA). The inhibitory effect of arachidonic acid on PGE2-induced cAMP accumulation was prevented by the PKC inhibitor, RO318425, and was absent in cells in which PKC had been downregulated by exposure to PMA for 24 h. The effect of arachidonic acid was also prevented by the PDE inhibitor, 3-isobutyl-1-methylxanthine. Arachidonic acid was shown by immunoblotting to prevent induction of cyclooxygenase-2 by PGE2, forskolin or dibutyryl cAMP. The results indicate that arachidonic acid activates PDE through a mechanism involving PKC, counteracting a rise in intracellular cAMP in response to PGE2. The data suggest that arachidonic acid antagonizes PGE2signalling through cAMP in the bovine endometrium, possibly acting to ensure a rapid return to oestrus in the case of failure of the maternal recognition of pregnancy.

scholarly journals A 3′,5′ Cyclic AMP (cAMP) Phosphodiesterase Modulates cAMP Levels and Optimizes Competence in Haemophilus influenzae Rd

1998 ◽  
Vol 180 (17) ◽  
pp. 4401-4405 ◽  
Author(s):  
Leah P. Macfadyen ◽  
Caixia Ma ◽  
Rosemary J. Redfield
Keyword(s):  
Cyclic Amp ◽  
Haemophilus Influenzae ◽  
Competence Development ◽  
Intracellular Camp ◽  
Camp Phosphodiesterase ◽  
E Coli ◽  
Sugar Fermentation ◽  
Endogenous Production ◽  
Camp Levels ◽  
Dependent Processes

ABSTRACT Changes in intracellular 3′,5′ cyclic AMP (cAMP) concentration regulate the development of natural competence inHaemophilus influenzae. In Escherichia coli, cAMP levels are modulated by a cAMP phosphodiesterase encoded by the cpdA gene. We have used several approaches to demonstrate that the homologous icc gene of H. influenzae encodes a functional cAMP phosphodiesterase and that this gene limits intracellular cAMP and thereby influences competence and other cAMP-dependent processes. In E. coli, expression of cloned icc reduced both cAMP-dependent sugar fermentation and β-galactosidase expression, as has been shown forcpdA. In H. influenzae, an icc null mutation increased cAMP-dependent sugar fermentation and competence development in strains where these processes are limited by mutations reducing cAMP synthesis. When endogenous production of cAMP was eliminated by a cya mutation, an icc strain was 10,000-fold more sensitive to exogenous cAMP than anicc + strain. The icc strain showed moderately elevated competence under noninducing conditions, as expected, but had subnormal competence increases at onset of stationary phase in rich medium, and on transfer to a nutrient-limited medium, suggesting that excessive cAMP may interfere with induction. Consistent with this finding, a cya strain cultured in 1 mM cAMP failed to develop maximal competence on transfer to inducing conditions. Thus, by limiting cAMP levels, the H. influenzae cAMP phosphodiesterase may coordinate its responses to nutritional stress, ensuring optimal competence development.

Metabolic regulation of endoglucanase synthesis in Trichoderma reesei: participation of cyclic AMP and glucose-6-phosphate

1993 ◽  
Vol 39 (3) ◽  
pp. 342-347 ◽  
Author(s):  
Sergej Šesták ◽  
Vladimír Farkaš
Keyword(s):  
Cyclic Amp ◽  
Trichoderma Reesei ◽  
Catabolite Repression ◽  
Metabolic Regulation ◽  
Phosphodiesterase Inhibitor ◽  
Phosphate Level ◽  
Intracellular Camp ◽  
Intracellular Level ◽  
Dibutyryl Cyclic Amp ◽  
Low Concentrations

The synthesis of endoglucanase by young induced mycelia of Trichoderma reesei QM 9414 incubated in the presence of 1 mM sophorose (a potent cellulase inducer) was stimulated or repressed by additions of dibutyryl cyclic AMP (dBcAMP), depending on the concentration. At low concentrations (10−6 and 10−5 M), dBcAMP stimulated the formation of endoglucanase; higher concentrations of dBcAMP (10−3 and 10−2 M) repressed the synthesis of endoglucanase. Addition of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX) at 1 and 10 μM concentrations to young induced mycelia caused an increase in intracellular cAMP and stimulated the production of endoglucanase. Neither exogenous dBcAMP nor IBMX was capable of inducing endoglucanase synthesis by itself, and neither was able to relieve catabolite repression of endoglucanase synthesis caused by glucose. All of the monosaccharides tested caused a more or less transient increase in intracellular cAMP. However, the effect of these treatments on endoglucanase synthesis was varied. The phosphorylable hexoses, both metabolizable and nonmetabolizable, increased the intracellular level of glucose-6-phosphate or its analogs and repressed endoglucanase synthesis. Nonphosphorylable sugars, such as 6-deoxyglucose, xylose, L-fucose, and (or) L-sorbose, did not influence the glucose-6-phosphate level and stimulated endoglucanase production to varying degrees. It is concluded that both cAMP and glucose-6-phosphate are involved in regulating cellulase synthesis in T. reesei. However, these factors seem to act in opposing directions.Key words: endoglucanase, induction, catabolite repression, metabolic regulation, glucose-6-phosphate, cyclic AMP, Trichoderma reesei.

scholarly journals Cyclic AMP-Independent Regulation of Protein Kinase A Substrate Phosphorylation by Kelch Repeat Proteins

2005 ◽  
Vol 4 (11) ◽  
pp. 1794-1800 ◽  
Author(s):  
Ailan Lu ◽  
Jeanne P. Hirsch
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Protein Kinase A ◽  
Intracellular Camp ◽  
Invasive Growth ◽  
Camp Phosphodiesterase ◽  
Α Subunit ◽  
Substrate Phosphorylation ◽  
Kinase A ◽  
In Cells

ABSTRACT Pseudohyphal and invasive growth in the yeast Saccharomyces cerevisiae is regulated by the kelch repeat-containing proteins Gpb1p and Gpb2p, which act downstream of the G protein α-subunit Gpa2p. Here we show that deletion of GPB1 and GPB2 causes increased haploid invasive growth in cells containing any one of the three protein kinase A (PKA) catalytic subunits, suggesting that Gpb1p and Gpb2p are able to inhibit each of these kinases. Cells containing gpb1Δ gpb2Δ mutations also display increased phosphorylation of the PKA substrates Sfl1p and Msn2p, indicating that Gpb1p and Gpb2p are negative regulators of PKA substrate phosphorylation. Stimulation of PKA-dependent signaling by gpb1Δ gpb2Δ mutations occurs in cells that lack both adenylyl cyclase and the high-affinity cyclic AMP (cAMP) phosphodiesterase. This effect is also seen in cells that lack the low-affinity cAMP phosphodiesterase. Given that these three enzymes control the synthesis and degradation of cAMP, these results indicate that the effect of Gpb1p and Gpb2p on PKA substrate phosphorylation does not occur by regulating the intracellular cAMP concentration. These findings suggest that Gpb1p and Gpb2p mediate their effects on the cAMP/PKA signaling pathway either by inhibiting the activity of PKA in a cAMP-independent manner or by activating phosphatases that act on PKA substrates.

Forskolin and thyrotrophin stimulation of rat FRTL-5 thyroid cell growth: the role of cyclic AMP

1987 ◽  
Vol 114 (2) ◽  
pp. 199-205 ◽  
Author(s):  
P. A. Ealey ◽  
C. A. Ahene ◽  
J. M. Emmerson ◽  
N. J. Marshall
Keyword(s):  
Cyclic Amp ◽  
Dose Range ◽  
Phosphodiesterase Inhibitor ◽  
Lag Phase ◽  
Thyroid Cell ◽  
Intracellular Camp ◽  
Camp Levels ◽  
Tsh Stimulation ◽  
Stimulation Of

ABSTRACT The adenylate cyclase stimulator forskolin increases intracellular cyclic AMP (cAMP) in rat FRTL-5 cells within minutes and, after a lag phase of 20–24 h, an increase of cells in metaphase is seen. The dose– response relationships were similar in both systems, with significant increases in the number of metaphases observed at ∼0·1 μmol/l and a doubling of cAMP levels at 1 μmol/l, whilst doses of 0·1 mmol/l and above proved cytotoxic. An involvement of intracellular cAMP as a positive intermediate in cell division was further suggested by the finding that a low dose of forskolin (0·1 μmol/l) potentiated TSH stimulation of mitosis. Isobutyl methyl xanthine (IBMX), a phosphodiesterase inhibitor, also acted as a mitogen and potentiated TSH action. Moreover, the simultaneous inclusion of low doses of IBMX and forskolin additionally potentiated TSH stimulation of mitosis. An analogue of cAMP, dibutyryl cAMP, also stimulated mitosis and acted over a restricted dose range, with maximal stimulation at 1 mmol/l. We conclude that cAMP may act as a positive signal for FRTL-5 thyroid cell proliferation. J. Endocr. (1987) 114, 199–205

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