The Effect of Aging on β-Adrenoceptor-Stimulated Cyclic AMP Formation in Human Lymphocytes

The adenylate cyclase system of the yeast Saccharomyces cerevisiae contains many proteins, including the CYR1 polypeptide, which is responsible for catalyzing the formation of cyclic AMP from ATP, RAS1 and RAS2 polypeptides, which mediate stimulation of cyclic AMP synthesis by guanine nucleotides, and the yeast GTPase-activating protein analog IRA1. We have previously reported that adenylate cyclase is only peripherally bound to the yeast membrane. We have concluded that IRA1 is a strong candidate for a protein involved in anchoring adenylate cyclase to the membrane. We base this conclusion on the following criteria: (i) a disruption of the IRA1 gene produced a mutant with very low membrane-associated levels of adenylate cyclase activity, (ii) membranes made from these mutants were incapable of binding adenylate cyclase in vitro, (iii) IRA1 antibodies inhibit binding of adenylate cyclase to the membrane, and (iv) IRA1 and adenylate cyclase comigrate on Sepharose 4B.

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Isolation, characterization and distribution of adenosine 3′:5′-cyclic monophosphate from Pinus radiata

Biochemical Journal ◽

10.1042/bj1750931 ◽

1978 ◽

Vol 175 (3) ◽

pp. 931-936 ◽

Cited By ~ 4

Author(s):

T Wilson ◽

E Moustafa ◽

A G C Renwick

Keyword(s):

Statistical Analysis ◽

Cyclic Amp ◽

Pinus Radiata ◽

Degrees Of Freedom ◽

Binding Assay ◽

Gel Filtration ◽

Plant Tissues ◽

Competitive Binding Assay ◽

Cyclic Monophosphate ◽

Solvent Systems

Cyclic AMP was extracted in 0.1 M-HCl from tissues of Pinus radiata and purified by gel filtration on Sephadex G-10, and chromatography on Dowex AG1 (X2) and polyethyleneimine-cellulose in two separate solvent systems. Presumptive cyclic AMP from 10kg batches of pine needles was characterized by countercurrent distribution in the presence of cyclic [8-3H]AMP. Statistical analysis of the curves for radioactivity and mass (determined by the Gilman competitive-binding assay) showed that the fit of the curves was highly significant for seven degrees of freedom. The distribution of cyclic AMP within P. radiata and various other plant tissues was determined by the Gilman procedure. The results suggest that there is no relationship between variations in cyclic AMP concentrations and the known function of the tissue in which it was measured.

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Regulation of adenylate cyclase and cyclic AMP phosphodiesterase by 5-hydroxytryptamine and calcium ions in blowfly salivary-gland homogenates

Biochemical Journal ◽

10.1042/bj2040153 ◽

1982 ◽

Vol 204 (1) ◽

pp. 153-159 ◽

Cited By ~ 16

Author(s):

I Litosch ◽

M Fradin ◽

M Kasaian ◽

H S Lee ◽

J N Fain

Keyword(s):

Salivary Gland ◽

Cyclic Amp ◽

Adenylate Cyclase ◽

Guanine Nucleotides ◽

Cyclase Activity ◽

Adenylate Cyclase Activity ◽

Cyclic Amp Phosphodiesterase ◽

Maximal Stimulation ◽

Increased Activity ◽

Stimulation Of

Salivary-gland homogenates contain 5-hydroxytryptamine-stimulated adenylate cyclase. Half-maximal stimulation was obtained with 0.1 microM-5-hydroxytryptamine in the presence of added guanine nucleotides. Gramine antagonized the stimulation of cyclase caused by 5-hydroxytryptamine. In the presence of hormone, guanosine 5′-[gamma-thio]triphosphate produced a marked activation of adenylate cyclase activity. Stimulation of adenylate cyclase by forskolin or fluoride did not require the addition of guanine nucleotides or hormone. In the presence of EGTA, Ca2+ produced a biphasic activation of cyclase activity. Ca2+ at 1-100 microM increased activity, whereas 2000 microM-Ca2+ inhibited cyclase activity. The neuroleptic drugs trifluoperazine and chlorpromazine non-specifically inhibited adenylate cyclase activity even in the absence of Ca2+. The cyclic AMP phosphodiesterase activity in homogenates was not affected by Ca2+ or exogenous calmodulin. This enzyme was also inhibited by trifluoperazine in the absence of Ca2+. These results indicate that Ca2+ elevates adenylate cyclase activity, but had no effect on cyclic AMP phosphodiesterase of salivary-gland homogenates.

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Interactions between adenylate cyclase and the yeast GTPase-activating protein IRA1

Molecular and Cellular Biology ◽

10.1128/mcb.11.9.4591-4598.1991 ◽

1991 ◽

Vol 11 (9) ◽

pp. 4591-4598

Author(s):

M R Mitts ◽

J Bradshaw-Rouse ◽

W Heideman

Keyword(s):

Cyclic Amp ◽

Adenylate Cyclase ◽

Adenylate Cyclase System ◽

Gtpase Activating Protein ◽

Yeast Saccharomyces Cerevisiae ◽

Strong Candidate ◽

Sepharose 4B ◽

Stimulation Of ◽

Cyclic Amp Synthesis

The adenylate cyclase system of the yeast Saccharomyces cerevisiae contains many proteins, including the CYR1 polypeptide, which is responsible for catalyzing the formation of cyclic AMP from ATP, RAS1 and RAS2 polypeptides, which mediate stimulation of cyclic AMP synthesis by guanine nucleotides, and the yeast GTPase-activating protein analog IRA1. We have previously reported that adenylate cyclase is only peripherally bound to the yeast membrane. We have concluded that IRA1 is a strong candidate for a protein involved in anchoring adenylate cyclase to the membrane. We base this conclusion on the following criteria: (i) a disruption of the IRA1 gene produced a mutant with very low membrane-associated levels of adenylate cyclase activity, (ii) membranes made from these mutants were incapable of binding adenylate cyclase in vitro, (iii) IRA1 antibodies inhibit binding of adenylate cyclase to the membrane, and (iv) IRA1 and adenylate cyclase comigrate on Sepharose 4B.

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Acetylcholine inhibits positive inotropic effect of cholera toxin in ventricular muscle

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1982.243.3.h434 ◽

1982 ◽

Vol 243 (3) ◽

pp. H434-H441

Author(s):

A. J. Pappano ◽

P. M. Hartigan ◽

M. D. Coutu

Keyword(s):

Chick Embryo ◽

Cyclic Amp ◽

Adenylate Cyclase ◽

Cholera Toxin ◽

Positive Inotropic Effect ◽

Phosphodiesterase Inhibitor ◽

Cyclase Activity ◽

Adenylate Cyclase Activity ◽

Inotropic Effect ◽

Cyclic Monophosphate

Acetylcholine (ACh, 10(-6) M) had no effect on basal adenylate cyclase activity (3.4 +/- 0.56 pmol cyclic AMP . min-1 . mg wet wt-1), adenosine 3',5'-cyclic monophosphate (cyclic AMP) content (0.88 +/- 0.09 pmol/mg wet wt), or the force of contraction in paced (2.5 Hz) chick embryo right ventricles superfused with Tyrode solution. After 60-180 min of superfusion in the presence of cholera toxin (5 x 10(-6) g/ml), adenylate cyclase activity (1.7 times), cyclic AMP content (2.4 times), and contractility (2.4 times) had increased significantly above basal levels. ACh reversed the positive inotropic effect of cholera toxin but did not change the increased activity of adenylate cyclase and content of cyclic AMP obtained in cholera toxin. Stimulation of adenylate cyclase by isoproterenol (ISO) was inhibited by ACh in the absence and presence of cholera toxin. ACh did not change guanosine 3',5'-cyclic monophosphate (cyclic GMP) content in the absence or presence of cholera toxin. Cholera toxin has actions on chick embryo ventricle similar to those of the beta-adrenergic agonist, ISO, and the phosphodiesterase inhibitor, isobutylmethylxanthine. The ability of ACh to reverse the positive inotropic effect of cholera toxin without preventing the accumulation of cyclic AMP may involve the prevention or reversal of cyclic AMP-dependent phosphorylation. In this regard, reduction of Ca2+ influx through voltage-sensitive membrane channels may be an essential component of muscarinic inhibition.

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