Physiological and Biochemical Aspects of “P”-Site-Mediated Inhibition of Adenylyl Cyclase

Johnson, Roger A.; Yeung, S.-M. H.; Bushfield, Mark; Stübner, D.; Shoshani, Ilana

doi:10.1007/978-1-4612-3400-5_25

Cited by 12 publications

(21 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…C1(AC5), C2(AC2), and G␣ s -GTP␥S were purified as described (13). Detergent-dispersed extract from rat brain and purified AC from bovine brain were prepared as described (23).…”

Section: Mant-itp␥s Mant-gtp␥s Mant-gmppnp Mant-gtp Mant-gdp 2ј-mentioning

confidence: 99%

“…To search for potential GC and UC activity of recombinant ACs 2 and 5, reaction mixtures contained 10 -100 M unlabeled GTP plus 1.5-3.0 Ci of [␣-32 P]GTP and 10 -100 M unlabeled UTP plus 1.5-3.0 Ci of [␣-32 P]UTP, respectively. AC activity in detergent-dispersed extract from rat brain and the activity of purified bovine brain AC were determined as described (23,30). Reaction mixtures contained 1.0 -1.5 Ci of [␣-32 P]ATP, 100 M unlabeled ATP, 5 mM MnCl 2 , and 100 M forskolin.…”

Section: Mant-itp␥s Mant-gtp␥s Mant-gmppnp Mant-gtp Mant-gdp 2ј-mentioning

confidence: 99%

“…However, ACT was the only cyclase studied that exhibited a higher V max in the presence of Mg 2ϩ than in the presence of Mn 2ϩ . In addition, the available literature evidence suggested that inhibitor sensitivity of cyclases in general is higher in the presence of Mn 2ϩ than in the presence of Mg 2ϩ (12,23,27,30,37,41). Therefore, we conducted the systematic analysis of the structure/activity relationships of inhibitors in the presence of Mn 2ϩ .…”

Section: Potent and Selective Ac Inhibition By Mant-itp␥s Relative Tomentioning

confidence: 99%

“…Inhibitor Analysis of Rat and Bovine Brain ACs-The dispersed rat brain AC and purified bovine brain AC have served as standard systems for the analysis of AC inhibitors for many years (4,23,25,28,30). Therefore, we wished to calibrate some of the inhibitors analyzed in this study with those standard systems.…”

Section: Potent and Selective Ac Inhibition By Mant-itp␥s Relative Tomentioning

confidence: 99%

“…The classic AC inhibitors are adenine nucleotides with a phosphate or polyphosphate at the 3Ј-O-ribosyl position (22)(23)(24)(25). These compounds are also referred to as P-site inhibitors.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Differential Inhibition of Adenylyl Cyclase Isoforms and Soluble Guanylyl Cyclase by Purine and Pyrimidine Nucleotides

Gille

Lushington

Mou

et al. 2004

Journal of Biological Chemistry

215

View full text Add to dashboard Cite

ACs 1 catalyze the conversion of ATP into the second messenger cAMP, PP i being the second product of the cyclase reaction. Mammals express nine membranous ACs (ACs 1-9) (1, 2) and a sAC that is predominantly expressed in testis (3). Bacillus anthracis and Bacillus pertussis produce the AC toxins EF and ACT, respectively, that are activated by Ca 2ϩ /calmodulin and act through excessive cAMP accumulation in host cells (4,5). sGC is structurally related to ACs 1-9 in the catalytic site and is activated by [6][7][8]. sGC catalyzes the formation of the second messenger cGMP from GTP. ACs 1-9 contain a tandem repeat structure with two transmembrane domains and two cytosolic domains (1, 2). The cytosolic domains are referred to as C1 and C2, respectively. Together, C1 and C2 form the catalytic site of AC. C1 and C2 also contain the regulatory sites for the stimulatory G-protein, G␣ s , for the inhibitory G-protein, G␣ i , and for the diterpene, forskolin. Catalytic activity of all AC isoforms depends on the presence of divalent cations (Mg 2ϩ or Mn 2ϩ ). Membranous ACs possess two Me 2ϩ -binding sites (9 -11). When mixed together, purified C1 and C2 form a functional AC that is efficiently activated by forskolin and G␣ s -GTP␥S (12, 13).AC isoforms differ from each other in their regulation (1, 2). ACs 1-9 are all activated by G␣ s , whereas sAC is activated by HCO 3 Ϫ (14). Forskolin activates ACs 1-8 but not AC9 or sAC. G␣ i inhibits ACs 1, 5, and 6. G-protein ␤␥ subunits exhibit stimulatory or inhibitory effects on AC isoforms. Ca 2ϩ /calmodulin stimulates ACs 1, 3, and 8. In addition, Mg 2ϩ and Mn 2ϩ show differential stimulatory effects on AC isoforms (15). More-

show abstract

“…C1(AC5), C2(AC2), and G␣ s -GTP␥S were purified as described (13). Detergent-dispersed extract from rat brain and purified AC from bovine brain were prepared as described (23).…”

Section: Mant-itp␥s Mant-gtp␥s Mant-gmppnp Mant-gtp Mant-gdp 2ј-mentioning

confidence: 99%

Section: Mant-itp␥s Mant-gtp␥s Mant-gmppnp Mant-gtp Mant-gdp 2ј-mentioning

confidence: 99%

Section: Potent and Selective Ac Inhibition By Mant-itp␥s Relative Tomentioning

confidence: 99%

Section: Potent and Selective Ac Inhibition By Mant-itp␥s Relative Tomentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Differential Inhibition of Adenylyl Cyclase Isoforms and Soluble Guanylyl Cyclase by Purine and Pyrimidine Nucleotides

Gille

Lushington

Mou

et al. 2004

Journal of Biological Chemistry

215

View full text Add to dashboard Cite

show abstract

Truncation and Alanine-Scanning Mutants of Type I Adenylyl Cyclase

Tang¹,

Stanzel²,

Gilman³

1995

Biochemistry

130

107

View full text Add to dashboard Cite

A variety of truncated constructs of type I and type II adenylyl cyclase have been synthesized in Sf9 cells using recombinant baculoviruses, as have a number of type I adenylyl cyclases with point mutations. Truncations indicate that the nonconserved C1b and C2b domains of adenylyl cyclase are not necessary for regulation of enzymatic activity by Gs alpha and forskolin. Point mutations demonstrate the requirement for both of the conserved (and homologous) domains of adenylyl cyclase (C1a and C2a) and the nonequivalence of these domains. Linkage of certain effects of mutations on the Km for substrate with alterations of the characteristics of P-site inhibition suggest that ATP and P-site inhibitors may bind to different conformations of the same site. However, other mutations affected only P-site inhibition. Although the mutations studied have not permitted assignment of unique functions to the two homologous domains, they have revealed novel phenotypes that appear to reflect the regulatory complexity of mammalian membrane-bound adenylyl cyclases, including the possibility of oligomerization of the enzymes.

show abstract

Stimulation of the type III olfactory adenylyl cyclase by calcium and calmodulin

1992

View full text Add to dashboard Cite

Characterization of adenylyl cyclases has been facilitated by the isolation of cDNA clones for distinct adenylyl cyclases including the type I and type III enzymes. Expression of type I adenylyl cyclase activity in animal cells has established that this enzyme is stimulated by calmodulin and Ca2+. Type III adenylyl cyclase is enriched in olfactory neurons and is regulated by stimulatory G proteins. The sensitivity of the type III adenylyl cyclase to Ca2+ and calmodulin has not been reported. In this study, type III adenylyl cyclase was expressed in human kidney 293 cells to determine if the enzyme is stimulated by Ca2+ and calmodulin. The type III enzyme was not stimulated by Ca2+ and calmodulin in the absence of other effectors. It was, however, stimulated by Ca2+ through calmodulin when the enzyme was concomitantly activated by either GppNHp or forskolin. The concentrations of free Ca2+ for half-maximal stimulation of type I and type III adenylyl cyclases were 0.05 and 5.0 microM Ca2+, respectively. These data suggest that the type III adenylyl cyclase is stimulated by Ca2+ when the enzyme is activated by G-protein-coupled receptors and that increases in free Ca2+ accompanying receptor activation may amplify the primary cyclic AMP signal.

show abstract

Physiological and Biochemical Aspects of “P”-Site-Mediated Inhibition of Adenylyl Cyclase

Cited by 12 publications

References 14 publications

Differential Inhibition of Adenylyl Cyclase Isoforms and Soluble Guanylyl Cyclase by Purine and Pyrimidine Nucleotides

Differential Inhibition of Adenylyl Cyclase Isoforms and Soluble Guanylyl Cyclase by Purine and Pyrimidine Nucleotides

Truncation and Alanine-Scanning Mutants of Type I Adenylyl Cyclase

Stimulation of the type III olfactory adenylyl cyclase by calcium and calmodulin

Contact Info

Product

Resources

About