Distinct Characteristics of the Basal Activities of Adenylyl Cyclases 2 and 6

Pieroni, Joseph P.; Harry, Anya; Chen, Jianqiang; Jacobowitz, Ofer; Magnusson, Ronald P.; Iyengar, Ravi

doi:10.1074/jbc.270.36.21368

Cited by 81 publications

(80 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The exchange of Mn 2ϩ against Mg 2ϩ decreased the apparent V max values of ACs 1, 2, and 5 2-4-fold with little effect on apparent K m values. The lack of effect of the Mn 2ϩ /Mg 2ϩ exchange on apparent substrate affinity of AC5 was reported before (10), and prominent decreases in apparent V max by exchanging Mn 2ϩ against Mg 2ϩ are in accordance with the literature as well (15,28). Compared with Mn 2ϩ , Mg 2ϩ decreased substrate affinity of EF 4-fold and increased V max by 30%.…”

Section: Enzyme Kinetics Of Cyclases and Inhibition Of Cyclases By Masupporting

confidence: 77%

“…it requires both ATP/Me 2ϩ and free Me 2ϩ (9 -11). As is common practice (10,12,15,33), we conducted cyclase experiments with varying concentrations of NTP/Me 2ϩ and a fixed concentration of free Me 2ϩ (see "Experimental Procedures"). Because we did not vary free Me 2ϩ concentrations, our kinetic data underestimate true V max and K m values.…”

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

confidence: 99%

“…4) prompted us to conduct a systematic analysis of the structure/activity relationships of purine and pyrimidine nucleotides for inhibition of AC and sGC. We analyzed purified catalytic AC subunits (C1⅐C2) (12,13), recombinant ACs 1, 2, 5, and 6 expressed in Sf9 insect cell membranes (15,65,66), S49 wt membranes (expressing ACs 6 and 7) (37, 67), membranes from uninfected Sf9 cells (expressing an AC of as yet unknown identity) (46,65), and purified sGC (7,8), sAC (3), EF, and ACT (4,5).…”

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

confidence: 99%

See 2 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

214

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

Section: Enzyme Kinetics Of Cyclases and Inhibition Of Cyclases By Masupporting

confidence: 77%

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%

See 1 more Smart Citation

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

214

View full text Add to dashboard Cite

show abstract

“…For example, a 2-fold increase in intracellular adenylyl cyclase can have profound biological consequences (23), and a 1.4-fold increase in Cyp3a expression levels has a significant biological impact on drug metabolism in SPF mice (24). Thus, while the magnitude of the change in antifungal susceptibility is numerically small, it was consistently reproduced.…”

Section: Figurementioning

confidence: 75%

Ab binding alters gene expression in Cryptococcus neoformans and directly modulates fungal metabolism

McClelland¹,

Nicola²,

Prados-Rosales³

et al. 2010

J. Clin. Invest.

View full text Add to dashboard Cite

“…6), given that the catalytic domains of adenylyl cyclases are highly homologous (up to 65% amino acid identity) and are assumed to be similar in tertiary structure. This latter assumption may be a little simplistic, given the rather divergent basal activities of different adenylyl cyclase species (26) and therefore, presumably, the conformational transitions associated with catalytic activity. Indeed, it is not difficult to imagine that the Mg 2ϩ -binding sites and adjacent amino acids in the catalytic domain of Ca 2ϩ -insensitive adenylyl cyclases may just never quite adopt the conformation that allows Ca 2ϩ to bind with high affinity.…”

Section: Discussionmentioning

confidence: 99%

A Critical Interplay between Ca2+ Inhibition and Activation by Mg2+ of AC5 Revealed by Mutants and Chimeric Constructs

Hu¹,

Nakata²,

Gu³

et al. 2002

Journal of Biological Chemistry

View full text Add to dashboard Cite

Adenylyl cyclase type 5 (AC5) is sensitive to both high and low affinity inhibition by Ca 2؉ . This property provides a sensitive feedback mechanism of the Ca 2؉ entry that is potentiated by cAMP in sources where AC5 is commonly expressed (e.g. myocardium). Remarkably little is known about the molecular mechanism whereby Ca 2؉ inhibits AC5. Because previous studies had showed that Ca 2؉ Ca 2ϩ in submicromolar concentrations exerts type-specific effects on adenylyl cyclases in in vitro assays (1, 2). The cation stimulates AC1 1 and AC8 in a calmodulin-dependent manner and inhibits AC5 and AC6 apparently independently of calmodulin (3). These effects are mirrored in intact cells when [Ca 2ϩ ] i is elevated by physiological means. Consequently, this regulation has been proposed to provide a device for harmonizing the activities of cAMP and Ca 2ϩ signaling pathways (1). At supramicromolar concentrations, Ca 2ϩ inhibits all adenylyl cyclases. The significance of this latter effect is unknown. Early kinetic analyses of uncharacterized adenylyl cyclase activity had led to the suggestion that this low affinity inhibition of adenylyl cyclases represented competition by Ca 2ϩ for an allosteric Mg 2ϩ regulatory site (4, 5). Low affinity inhibition was recently established to be a general property of representatives of various identified adenylyl cyclase (6). Kinetic analyses revealed that for each adenylyl cyclase, the low affinity inhibition could be described as a competition between Ca 2ϩ inhibition and Mg 2ϩ activation. Mg 2ϩ has long been known not only to participate in the substrate (MgATP 2Ϫ ) but also to activate adenylyl cyclase at concentrations beyond those required to maximize the concentration of metal-chelated substrate (7). X-ray crystallographic analysis of an adenylyl cyclase catalytic core derived from the AC5 C1a and AC2 C2a 2 domains revealed two metal-binding sites (8). One site (the "A site") appears to form a tetrahedral coordination sphere, (with the ␣-phosphate of ATP, two carboxylate oxygens from two aspartate residues, and a water molecule), whereas the other (the "B site") forms an octahedral coordination sphere (an oxygen from the same aspartates as in the A site, an unesterified oxygen from each of the ␣-, ␤-, and ␥-phosphates of ATP, and the backbone carbonyl of Ile 397 ). It appears as though the A site enables the catalysis of the attack by the 3Ј-hydroxyl of ribose on the ␣-phosphate. Whether one or the other of these sites corresponds to the allosteric Mg 2ϩ regulatory site suggested by kinetic analyses is not clear. However, this structure furnishes a context in which to ask whether these sites might provide the mechanism whereby Ca 2ϩ exerts some of its effects on adenylyl cyclase. Zimmerman et al. (9) described a number of mutants of AC5 in the immediate vicinity of the catalytic site in which the regulation by Mg 2ϩ was altered. We have used these mutants to determine whether there is a link between Mg 2ϩ regulation and sensitivity to inhibition by Ca 2ϩ . Because AC5 is also sus...

show abstract

Distinct Characteristics of the Basal Activities of Adenylyl Cyclases 2 and 6

Abstract: Regulation of basal activities of adenylyl cyclase (AC) 2 and 6, expressed in Sf9 cells by infection with recombinant baculovirus, was studied. An antipeptide antibody that recognizes AC2 and AC6 with equal sensitivity was used to establish that equivalent levels were expressed.

Cited by 81 publications

References 33 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

Ab binding alters gene expression in Cryptococcus neoformans and directly modulates fungal metabolism

A Critical Interplay between Ca2+ Inhibition and Activation by Mg2+ of AC5 Revealed by Mutants and Chimeric Constructs

Contact Info

Product

Resources

About