scholarly journals Adenosine 3′:5′-cyclic monophosphate-dependent protein kinase(s) of rat ovarian cells. Gonadotropin regulation of adenosine 3′:5′-cyclic monophosphate-receptor activity

1978 ◽  
Vol 172 (3) ◽  
pp. 433-442 ◽  
Author(s):  
K. M. Jairam Menon ◽  
Salman Azhar
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Binding Sites ◽  
Binding Capacity ◽  
Receptor Activity ◽  
Dependent Protein Kinase ◽  
Ovarian Cell ◽  
Cyclic Monophosphate ◽  
Ovarian Cells ◽  
Dependent Protein

Regulation of cyclic AMP-dependent protein kinase, cyclic AMP-receptor activity and intracellular cyclic AMP concentrations by choriogonadotropin was studied in ovarian cells prepared from 26-day-old rats. A close correlation was observed between phospho-transferase activity and cyclic AMP-receptor activity in 12000g supernatant fractions from rat ovarian homogenate. The apparent activation constant (Ka) and I50 (concentration required to produce 50% inhibition) of different cyclic nucleotides for phosphotransferase and cyclic AMP receptor activities respectively were also determined. Cyclic AMP and 8-bromo cyclic AMP were most effective, giving Ka values of 0.08 and 0.09μm and I50 of 0.12 and 0.16μm respectively. Other nucleotides were also effective, but required higher concentrations to give a comparable effect. An increased concentration of cyclic AMP produced by choriogonadotropin (1μg/ml) treatment was accompanied by decreased cyclic AMP binding as early as 5min after hormone addition. Choriogonadotropin also stimulated the protein kinase activity ratio (−cyclic AMP/+cyclic AMP) under identical experimental conditions. The phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine potentiated the action of choriogonadotropin on the three parameters measured in a dose- and time-dependent manner. The maximal cyclic AMP-binding capacity, as determined by cyclic AMP-exchange assay, remained unchanged before and after hormone addition. The endogenously bound cyclic AMP was determined from the difference between the maximal binding capacity and the exogenously bound cyclic AMP. With different choriogonadotropin concentrations, a quantitative correlation was established between maximal binding capacity, exogenous binding and endogenous binding activities. Approx. 60% of total binding sites were endogenously occupied in untreated cells, and choriogonadotropin (1μg/ml) treatment fully saturated available binding sites with a parallel 10-fold increase in cellular cyclic AMP. The present results provide evidence for a probable intracellular compartmentalization of cyclic AMP in the ovarian cell, and suggest that in the unstimulated state all cyclic AMP present in the ovarian cell may not be available for protein kinase activation.

scholarly journals Calcineurin Inhibitor, FK506, Prevents Reduction in the Binding Capacity of Cyclic AMP-Dependent Protein Kinase in Ischemic Gerbil Brain

1997 ◽  
Vol 17 (4) ◽  
pp. 412-420 ◽  
Author(s):  
Kortaro Tanaka ◽  
Yasuo Fukuuchi ◽  
Hiroyuki Nozaki ◽  
Eiichiro Nagata ◽  
Taro Kondo ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Blood Vessels ◽  
Binding Capacity ◽  
Specific Inhibitor ◽  
Artery Occlusion ◽  
Carotid Artery Occlusion ◽  
Dependent Protein Kinase ◽  
Arterial Blood ◽  
Dependent Protein

We examined the effects of FK506, a specific inhibitor of calcineurin, on the binding capacity of cyclic AMP-dependent protein kinase (cAMP-DPK) in gerbils subjected to 2-h cerebral hemispheric ischemia. FK506 (0.1 mg/kg) was infused intravenously at 15 min prior to the induction of ischemia by common carotid artery occlusion. The binding capacity of cAMP-DPK was evaluated by autoradiographic analysis of the cAMP binding, and cerebral blood flow (CBF) was measured by the [14C] iodoantipyrine method. In the sham-operated gerbils, FK506 significantly increased mean arterial blood pressure and tended to decrease CBF, suggesting that FK506 may constrict systemic blood vessels as well as cerebral blood vessels. On the other hand, cAMP binding was not altered by FK506 in the sham-operated gerbils. In the ischemia group of gerbils, FK506 prevented any significant reduction of cAMP binding in the hippocampus CA1 and cerebral cortices on the ischemic side, whereas it exerted no significant influence on the cAMP binding of the nonischemic side. The values of CBF were comparable between the vehicle-treated gerbils and FK506-treated gerbils in the ischemic regions. Preservation of cAMP binding indicates that intracellular signal transduction via cAMP-DPK can be maintained by FK506 despite ischemia, suggesting that this agent may be beneficial for reducing ischemic tissue damage.

scholarly journals Ovarian adenosine 3′:5′-cyclic monophosphate-dependent protein kinase(s). Regulation by choriogonadotropin and lutropin in rat ovarian cells

1976 ◽  
Vol 158 (2) ◽  
pp. 175-182 ◽  
Author(s):  
M R Clark ◽  
S Azhar ◽  
K M J Menon
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Kinase Activity ◽  
Activity Ratio ◽  
Gel Filtration ◽  
Supernatant Fraction ◽  
Protein Kinase Activity ◽  
Dependent Protein Kinase ◽  
Ovarian Cells ◽  
Dependent Protein

Choriogonadotropin and lutropin have been found to activate cyclic AMP-dependent protein kinase in ovarian cells isolated by collagenase dispersion from immature rats. The stimulatory effect of gonadotropins was dependent on both hormone concentration and incubation time. Choriogonadotropin at 1 mug/ml fully stimulated the protein kinase activity within 5 min of incubation, and this effect was specific for choriogonadotropin and lutropin-like activity. In addition, protein kinase activity has been characterized with respect to salt sensitivity, cyclic AMP binding, and its responsiveness to gonadotropins and other peptide hormones. Ovarian protein kinase was susceptible to high salt concentrations. The addition of 0.3-1.0 M-NaCl in incubation medium increased the activity ratio with a concomitant decrease in cycle AMP-dependence. The salt effect on protein kinase was observed both from hormone-treated and untreated cells. The hormone-stimulated and unstimulated protein kinase activity was completely stable in the absence of NaCl. No change in the activity ratio was observed when cellular extracts were assayed for protein kinase activity either immediately or after 2 h in the absence of added salt. Gel filtration in the absence of NaCl of cellular extracts prepared from choriogonadotropin-treated and untreated cells showned only a single peak of protein kinase activity that was sensitive to exogenously added cyclic AMP. By contrast, when 0.5 M-NaCl was included in the column buffer, the chromatography of untreated extract showed two peaks of protein kinase activity. The first peak was sensitive to added cyclic AMP, whereas the second peak was insensitive to it. Under identical experimental conditions, protein kinase from gonadotropin-treated cells showed, on gel filtration, only one peak of activity that was totally insensitive to added cyclic AMP. DEAE-cellulose column chromatography of a 20000 g supernatant fraction resulted in a peak of kinase activity that eluted in approx. 0.15 M-NaCl, similar to the similar to the elution of type II protein kinases as described by Corbin et al. (1975) (J. Biol. Chem. 250, 218-225). Choriogonadotropin stimulation produced a decrease in the capacity of protein kinase to bind exogenous cyclic [3H]AMP, with a concomitant increase in the kinase activity ratio. These results are consistent with the notion that cyclic AMP, GENERATED IN SITU Under hormonal stimulation, binds tot he regulatory subunit of protein kinase with subsequent dissociation of the active catalytic subunit from the holoenzyme.

Adenosine 3′, 5′-cyclic-monophosphate dependent protein kinase and cyclic-AMP-binding in human mammary tumors

FEBS Letters ◽  
1977 ◽  
Vol 80 (1) ◽  
pp. 229-234 ◽  
Author(s):  
U. Eppenberger ◽  
K. Talmadge ◽  
W. Küng ◽  
E. Bechtel ◽  
J. Preisz ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Mammary Tumors ◽  
Dependent Protein Kinase ◽  
Cyclic Monophosphate ◽  
Dependent Protein ◽  
Human Mammary Tumors

scholarly journals Cyclic AMP-binding and cyclic AMP-dependent protein kinase activities in the cytosol of differentiating bone marrow erythroblasts

1981 ◽  
Vol 196 (3) ◽  
pp. 893-897 ◽  
Author(s):  
M S Setchenska ◽  
J G Vassileva-Popova ◽  
H R Arnstein
Keyword(s):  
Bone Marrow ◽  
Protein Kinase ◽  
Cyclic Amp ◽  
Binding Proteins ◽  
Kinase Activity ◽  
Binding Capacity ◽  
Protein Kinase Activity ◽  
Dependent Protein Kinase ◽  
Dividing Cells ◽  
Dependent Protein

Cytosolic cyclic AMP-binding capacity and cyclic AMP-dependent protein kinase activity have been studied in relation to differentiation and maturation of rabbit bone marrow erythroblasts. Using cells fractionated by velocity sedimentation at unit gravity, it was found that both activities decreased in dividing cells when calculated in terms of cell number but remained constant per cell volume. After the final cell division, cyclic AMP-dependent protein kinase activity did not change further, whereas cyclic AMP-binding capacity declined. There were no qualitative, but only quantitative, changes in the cyclic AMP-binding proteins that are present in the cytosol of developing erythroblasts. In the immature cells, the apparent KD for the interaction of binding proteins with cyclic AMP was 4 } 10(-8) M. The data suggest that changes in cyclic AMP-binding activity during differentiation of erythroid cells are due both to changes in the amount of binding proteins and in their affinity for cyclic AMP. Plasma membranes of erythroblasts were also able to bind cyclic AMP but only in dividing cells.

scholarly journals Regulation of jun-B expression by a cyclic AMP (cAMP)-dependent mechanism in human myeloid cells

Blood ◽  
1991 ◽  
Vol 78 (1) ◽  
pp. 83-88 ◽  
Author(s):  
R Datta ◽  
T Nakamura ◽  
ML Sherman ◽  
D Kufe
Keyword(s):  
Protein Kinase ◽  
Cyclic Amp ◽  
Myeloid Leukemia ◽  
Leukemia Cells ◽  
Intracellular Camp ◽  
Dependent Protein Kinase ◽  
Cyclic Monophosphate ◽  
Camp Dependent Protein Kinase ◽  
Dependent Protein ◽  
Jun B

Abstract The present studies have examined the regulation of the jun-B early response gene by cyclic AMP (cAMP)-dependent signaling pathways. The 2.0-kb jun-B transcript was at low but detectable levels in uninduced human HL-60 myeloid leukemia cells. In contrast, treatment with 1 mmol/L8-bromo-adenosine 3′,5′-cyclic monophosphate (8-Br-cAMP) in the presence of isobutylmethylxanthine, an inhibitor of cAMP-dependent phosphodiesterase, was associated with increases in jun-B transcripts that were maximal by 1 hour and then decreased to near pretreatment levels by 6 hours. Similar findings were obtained with 8–(4- chlorophenylthio)-adenosine 3′,5′-cyclic monophosphate (8-CPT-cAMP) and N6,2′–0-dibutyryladenosine 3′,5′-cyclic monophosphate (dBt-cAMP). jun-B transcripts were also increased with other agents that increase intracellular cAMP levels, such as prostaglandin E2 (PGE2) and forskolin. Moreover, inhibition of cAMP-dependent protein kinase by the isoquinolinesulfonamide H-8 blocked 8-Br-cAMP-induced increases in jun- B expression. The results of nuclear run-on assays demonstrate that treatment of HL-60 cells with PGE2, forskolin, 8-Br-cAMP, and dBt-cAMP is associated with increases in the rate of jun-B transcription. The present findings also demonstrate that the related jun-D gene is similarly regulated by a cAMP-dependent pathway. Taken together, these findings suggest that stimulation of cAMP-dependent protein kinase is involved in the induction of jun gene expression in myeloid leukemia cells.

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