Revision of Transmembrane Adenylyl Cyclases from Wed, 2014-04-16 11:26

Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor
mesabba@umich.edu

Citation: 

[Sabbatini, Maria E. (2013). Transmembrane Adenylyl Cyclases.]
Pancreapedia: Exocrine Pancreas Knowledge Base, DOI: 10.3998/panc.2013.8
AttachmentSize
PDF icon Transmembrane Adenylyl Cyclase296.68 KB

Gene symbols: ADCY1, ADCY2, ADCY3, ADCY4, ADCY5, ADCY6, ADCY7, ADCY8, ADCY9

1.  General Information

Adenylyl cyclases (AC) catalyze the conversion of ATP to cAMP and pyrophosphate.  There are nine different transmembrane AC isoforms activated by Gαs and each one has its own pattern of expression and regulation by calcium and other intracellular signals. In addition, there is a soluble adenylyl cyclase, which is independent of Gαs. In this Molecule page the basic structure, regulation and physiological roles of transmembrane AC in the exocrine pancreas will be discussed. For more details about the structure of AC, its regulation, and tissue distribution see recent reviews (5,62,81).

Structure of Transmembrane Adenylyl Cyclases

The nine transmembrane AC isoforms are each coded by a different gene on a different chromosome, with the exception that in the human, the genes that encode AC7 and AC9 are both located on chromosome 16 (57). Two splice variants of AC8 have been cloned and characterized in mammals. Mammalian transmembrane ACs are large (1,080-1,248 amino acids) proteins (from 120 to 151 kDa) that cross the plasma membrane 12 times in two cassettes of 6 transmembrane (TM) domains (15,40). The two cytosolic domains (C1 and C2) include putative ATP-binding domains (15). All of isoforms share a high sequence homology in the primary structure of their catalytic site and the same predicted three-dimensional structure. This structure consists of two hydrophobic domains (M1 and M2), each composed of 6 transmembrane-spanning domains followed by a large cytosolic domain. The combined C1 and C2 cytosolic domains constitutes the catalytic site and is regulated by isoform specific intracellular signals; it is also the site for interaction with forskolin and Gαs (19).

Figure 1. Crystal structure of Adenylyl Cyclase. a) The figure shows the catalytic domains of mammalian AC (C1 and C2) with Gαs (green) and Gαi. The location of forskolin (cyan) and P-site inhibitor (dark blue) is also appreciated. b) An alternate view from cytoplasmic side, showing forskolin and catalytic site. The interaction site of Giα with C1 domain is indicated by an arrow. This figure was obtained with permission from (62).

Regulation of Transmembrane Adenylyl Cyclases

Ligands binding to G protein coupled receptors (GPCRs) activate an intracellular, membrane-associated heterotrimeric G protein composed of three subunits: a guanine nucleotide binding the α subunit and a βγ heterodimer. When a stimulatory hormone binds its receptor, it becomes active by exchanging its bound GDP for guanosine triphosphate (GTP), which induces a conformational change and dissociation of the GTP-bound α subunit from the βγ heterodimer. There are several classes of α-subunits, one of which, the Gαs family, is able to activate all nine transmembrane AC isoforms, whereas others of the Gαi family, are able to inhibit AC. These are direct interactions between the α-subunits and AC. In addition to α-subunits, βγ-subunits of G proteins, and the intracellular messengers such as PKC, and/or calcium can also regulate the activity of AC.

Transmembrane ACs are classified into four groups based on regulatory properties as summarized below and shown in detail in Table 1:

-          Group I: calcium/calmodulin-stimulated AC1, AC3, AC8;

-          Group II: Gβγ-stimulated AC2, AC4, AC7;

-          Group III: Giα/calcium-inhibited AC5, AC6;

-          Group IV: isoform AC9 which is forskolin-, calcium- and Gβγ-insensitive.

Recently, AC9 has been shown to be inhibited by novel PKC isoforms and Gi/o proteins (17) and to be activated by Gq-coupled GPCRs through activation of calmodulin kinase II (18).

(+): AC is stimulated; (-): AC is inhibited; (=): AC activity is not modified. Data taken from (19, 50,81). * The molecular weight (MW) data was obtained from PhosphoSitePlus from Cell Signaling Technology, Inc.

2. Transmembrane adenylyl cyclases in the exocrine pancreas

Pancreatic receptors acting through transmembrane AC include secretin, vasoactive intestinal polypeptide (VIP) and somatostatin for exocrine pancreas and additionally adrenergic, as well as the two incretin hormones, gastric inhibitory polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) for islets of Langerhans. Current understanding of the role for AC in pancreatic exocrine cells comes primarily from studies that use pharmacologic stimulators and inhibitors of intracellular signals (1,7,14,30,48,51,54,72). This earlier work showed that phosphodiesterase inhibitors, such as 3-isobutyl-1-methylxantine (IBMX) augmented the increase in cAMP levels and amylase secretion caused by hormones such as VIP and secretin (28). AC activity was also demonstrated in pancreatic particulate fractions and semipurified plasma membranes (52,59). In one study, AC was localized by histochemistry that captured the enzymatic product with the heavy metal strontium in rat pancreatic fragments, which could then be localized by electron microscopy (85). The precipitate was localized to the basolateral membranes of acinar cells and enhanced following stimulation by secretin.

Recently, we established which transmembrane AC isoforms are expressed in intact mouse pancreas, isolated pancreatic acini and duct fragments (61). Using RT-PCR, five different transmembrane AC mRNAs were found in pancreatic exocrine cells: AC3, AC4, AC6, AC9 mRNAs were expressed in isolated pancreatic acini and duct fragments, whereas AC7 mRNA was only expressed in pancreatic duct fragments (Figure 2). Using real-time quantitative PCR, isolated pancreatic acini were shown to have higher transcript levels of AC6 compared to intact pancreas. Isolated duct fragments were shown to have higher transcript levels of AC4, AC6 and AC7 compared to the intact pancreas. Similar transcript levels of AC3 and AC9 were observed in pancreas, acini and ducts.

 

Figure 2. Tissue distribution of AC isoforms in pancreatic acinar cell and duct cell membranes. Note that the intracellular localization of these AC isoforms has not been established yet.

Based on the above we postulated that AC6 is the primary isoform regulating the response to cAMP-mobilized secretagogues in the exocrine pancreas. When acini were prepared from mice with genetically deleted AC6 (74), isolated pancreatic acini showed a decrease in both cAMP generation and PKA activation upon stimulation by VIP, secretin or forskolin (61). Using isolated pancreatic duct fragments, the reduction in the cAMP/PKA pathway activity with these agonists was even larger. The absence of AC6 partially reduced cAMP-dependent secretagogue-stimulated amylase secretion from acinar cells and almost abolished fluid secretion in both in vivo and from isolated duct fragments (61). The action of other intracellular signals, such as calcium or Epac1 (11,60), was not modified by the absence of AC6. Although an increase in protein content of PKA regulatory subunit was observed in mice with genetically deleted AC6, no changes in the morphology of the pancreas or in the protein content of other molecular elements of the exocrine pancreas, such as amylase, keratin 19, Epac1 and Rap1, was observed (61).

Although cAMP produced by AC provides a supporting role to intracellular calcium in pancreatic acinar cells, cAMP provides the major intracellular control in duct function.  AC in duct fragments is stimulated by secretin and VIP and inhibited by somatostatin.  As previously indicated, five isoforms of AC are present in duct fragments: AC3, AC4, AC6, AC7, and AC9, though AC6 appears to be of major importance in fluid secretion (61).  Whether all 5 isoforms are present in all duct cells or are distributed differentially in different duct sizes or types (intercalated, intralobular, interlobular and the main pancreatic duct) requires further study. cAMP in duct cells activates PKA and among other targets phosphorylates Cystic Fibrosis Transmembrane Conductance Regulator (CFTR), thereby activating this anion channel, which is essential for bicarbonate secretion (3).

Consistent with calcium’s known direct inhibitory effects on AC6, the calcium chelator BAPTA-AM enhanced VIP-stimulated cyclic AMP generation in pancreatic acini, but  inhibition of the calcium-activated proteins calcineurin and calmodulin did not modify the response to VIP (61). The capacitive entry of calcium (secondary to the emptying of the intracellular calcium pool), has been proposed to play a major role in negatively regulating AC6 activity (43), but needs to be studied in pancreatic acini.

Secretagogues able to activate transmembrane ACs in the exocrine pancreas.

Secretin and VIP are two secretagogues which, upon receptor occupancy, elicit an activation of AC. Secretin is bound to an unique receptor, which is highly expressed in both pancreatic acini and ductal epithelial cells and is low or undetectable in islets and pancreatic vessels (76). VIP has two different receptors, VPAC1 and VPAC2, which are also present in pancreatic acini. Both secretin and VIP receptors are GPCRs belong to class II, unlike H2 and β-adrenergic receptors which belong to class I (49,76). The effect of VIP on cAMP levels and amylase secretion are mediated 90 % by activation of VPAC1 and 10 % by VPAC2 (35).

Secretin and VIP show a different pattern of intracellular signaling and secretory responses compared to those induced by secretagogues such as cholecystokinin (CCK) that increase intracellular calcium. Both secretin and VIP increase pancreatic amylase secretion while increasing cAMP levels (64,68). However, there is a lack of relationship between the magnitude of amylase secretion and cAMP formation. Indeed, amylase secretion in response to secretin remains low, whereas cAMP formation increases 12-45 fold above basal (41,75). Secretin acts via a complex signal transduction pathway; secretin action in acinar cells is, likely mediated by a dual effect on the cAMP levels and the phospholipase C (PLC) pathway because an increase in phosphoinositide hydrolysis has been shown (41,75). In rat pancreatic acini, the threshold concentration of secretin required to increase phosphoinositides hydrolysis was higher than that required for activation of AC (75). Another difference between secretin/VIP and the calcium-mediated secretagogues is the concentration-dependence relationship of amylase secretion. The dose-response relationship for calcium-mediated secretagogues is biphasic (i.e. as the secretagogue concentrations increase, amylase secretion increases, becomes maximal and then decreases at high concentrations of the secretagogue), whereas the dose-response relationship for secretin or VIP is monophasic with maximal amylase secretion being maintained with supramaximal concentrations of cAMP-dependent secretagogues (56). An interesting difference is in the phosphoprotein profile. Both secretin and VIP specifically induce changes in the phosphorylation of specific acinar phosphoproteins whose molecular weight is lower than 35 KDa (8). Both VIP and secretin have increased the phosphorylation of an unique protein of 52 KDa and pI 5.66, as well as several proteins affected by the cholinergic agonist carbachol (9). These findings indicate that while the identity of only some of these phosphoproteins is known, the pattern supports the concept of some overlaps and some distinct differences between responses to calcium- and cAMP-mediated secretagogues.

Both secretin and VIP also participate in other regulatory function in pancreatic acini. In rat pancreatic acini, secretin sensitizes some, but not all, of the effects of caerulein through the cAMP/PKA pathway (35,56). In the presence of secretin, submaximal concentrations of caerulein were able to elicit intracellular zymogen activation (46), as well as cell injury and actin cytoskeletal reorganization (56). However, the sensitizing effect of secretin seems to be selective because secretin does not sensitize acinar cells to caerulein-induced inhibition of digestive enzyme secretion, increase in intracellular calcium levels or activation of either ERK1/2 or NF-κB, which are indicators of cellular stress (56). Secretin increases amylase secretion induced by physiological concentrations of carbachol, but reduced secretion induced by supraphysiological concentrations of carbachol (12).

VIP was reported to positively modulate calcium signals in rat pancreatic acini in the presence of carbachol. Specifically, VIP accelerated the speed of the apical to basal calcium waves induced by carbachol in rat pancreatic acinar cells by acting on ryanodine receptors (66). The effect was correlated with an enhancement in protease activation. What’s intriguing is that a similar acceleration of the acinar cell calcium wave and enhancement of protease activation was seen with the administration of clinically relevant concentrations of ethanol (53). The effect of alcohol was abrogated by cAMP inhibition (Husain SZ, personal communication). Taken together, these findings suggest that cAMP (and ethanol through generation of cAMP) modulates ryanodine receptor calcium opening and the subsequent pathologic activation of intra-acinar proteases.  Whether the effect of cAMP is through PKA, Epac, or another mechanism requires further study.

Other cell surface receptors have been found on pancreatic exocrine cells and can affect cAMP levels by modulating AC activities. Somatostatin, unlike secretin and VIP, inhibits AC through the somatostatin type 2 receptor (ss2R), which have been found on pancreatic acinar cells (31,48). Several studies indicate that somatostatin receptors are coupled to Gi proteins because its response is inhibited by pertussis toxin (51,77). Studies in vivo have shown that somatostatin inhibits CCK and/or secretin-stimulated pancreatic secretion (6,31,39,51,69). Studies in vitro have also shown that somatostatin inhibits amylase secretion by inhibition of AC (31,51,69). The mechanism by which the reduction occurs involved a decrease in both cAMP generation and calcium sensitivity (31,51,77). 

Epidermal growth factor (EGF) has shown to have a dual effect on AC activity in rat pancreatic acini.  Whereas EGF stimulated basal cAMP generation and amylase secretion, EGF inhibited VIP- and forskolin-induced cAMP generation and amylase secretion (72). EGF has also shown to release calcium from intracellular stores in rat pancreatic acini (10) and AR42J cells (67).

In rat pancreatic acini, increased cAMP and PKA activation by concentrations of cholecystokinin (CCK) higher than 1 nM have been reported (47). In dispersed acinar cells prepared from guinea-pigs pancreas, both VIP and secretin, but not CCK octapeptide, increased cAMP levels (45). In the same study, using homogenates of acinar cells, secretin, VIP, and CCK, all increased AC activity. Unlike CCK, carbachol has not modified the activity of PKA or cAMP levels (45). These differences in the response to CCK on cAMP levels can be explained based on differences between species as described below. 

The effects of AC-stimulated pancreatic secretion is species dependent.

Several studies show differences between species regarding to the ability of hormones and neurotransmitters to stimulate pancreatic enzyme secretion through AC activation. VIP and secretin, as well as pharmacological agents which increase cAMP levels, stimulate pancreatic secretion in guinea-pigs, but not in other rodent species (4,21,27,29,34,55,58,70). In mouse, rat and cat pancreas, agonists working via cAMP have little or no effect on amylase secretion (7,9,68). The increase in cAMP levels and its association with amylase release has been characterized in guinea-pig pancreas (38,86). Significant differences occur in acinar cells from rat pancreas; rat acinar cells differ from guinea-pig acinar cells in the number and type of receptors that interact with VIP and secretin. In rat acinar cells, the cellular cAMP appears to be coupled with the stimulation of enzyme secretion (16,25). In the guinea-pig and mouse, secretin is less potent than VIP in stimulating amylase secretion (7,27,55).

3. Tools for the study of Transmembrane Adenylyl Cyclases

a. Plasmids and viral vectors

- Both AC2 and AC9 in pCDNA3 vectors have been described (44). AC6 cDNA can be obtained from the Mammalian Gene Collection (ATCC).

- An E1-deleted recombinant adenovirus encoding murine AC6 (with an AU1 tag, a 6 amino acid epitope: DTYRY1) has been described (26).

- AC5-YPF-pcDNA3 has been described (24).

- Plasmids coding for GST-fusion proteins: GST-fusion to 1-61 of bovine AC1, GST-fusion to 1-43 of rat AC2, and GST-fusion of human AC9 were cloned into pGEX-4T; GST-fusion to 1-77 of rat AC3 was cloned into pGEX-CS. All of these plasmids have been described (44).

b.  siRNA

Specific siRNA can be obtained from Thermo Scientific/Dharmacon, Santa Cruz Biotechnology. Silencer Cy3-labeled custom siRNA for AC8 can be obtained from Ambion (Austin, TX) (13,71).

c.  Pharmacologic inhibitors

Adenosine and various nucleoside analogs known as P-site inhibitors inhibit all isoforms of AC (23,36). Those derivatives include 2’,5’-dideoxyadenosine-3’-tetraphosphate,2’,5’-dideoxy-3’-ATP. These inhibitors are noncompetitive or uncompetitive with respect to substrate ATP and are more potent on activated forms of AC than the basal state.

d. Pharmacologic activators

Forskolin is a diterpene extracted from the root of the plant Coleus forskohlii that directly activate all isoforms of transmembrane ACs -except AC9 (57,65) by interacting with two homologous cytoplasmic domains (C1 and C2) that form the catalytic domain (73). The lack of effect of forskolin on AC9 may be accounted for by two residues, Ala112 and Tyr1082 of AC9, corresponding to Leu912 and Ser942 of AC2 (84). Although forskolin induces an increase in cAMP levels, it only slightly stimulates amylase secretion (20,37) and potentiates the response to secretagogues which induce calcium-mediated exocytosis (33). 

e. Antibodies

Antibodies against transmembrane ACs: Several antibodies to ACs are commercially available, but only a few show a band of the correct molecular weight. Anti-AC9 (Santa Cruz Biotechnology, Inc.) has been used in Western-blotting (44,61).  Another example is anti-AC5 from FabGennix Inc. This antibody has been used in Western-blotting and immunofluorescence (43).

f. Measurement of AC activity

1- Radioassay. Cells are incubated with (2,8-3H)-adenosine for 18 h and then pre-incubated with IBMX. Following stimulation of cells with stimulants for a specific period of time, proteins are precipitated with ice-cold 5% trichloroacetic acid containing cAMP. (3H)-cAMP is isolated by a sequential Dowex-alumina chromatography method. AC activity is calculated as the percentage of (3H)-cAMP formed of the total (3H)-ATP + (3H)-ADP + (3H)AMP pool, and the results are expressed as the ratio (cAMP/ATP + ADP +AMP) x 100 (80).

2- Membrane preparation and AC activity (2,22). Cells were collected, washed three times with phosphate-buffered saline (pH 7.4) and membranes were prepared in 5 mM Tris-HCl buffer (pH 7.4), containing 1 mM DTT and 1 mM EGTA. Membranes were resuspended in the above buffer. AC activity was measured in 40 mM Tris-HCl buffer (pH 7.4), containing 0.2 mM EGTA, 0.2 mM DTT, 100 mM NaCl, 10 mM MgCl2, 0.5 mM ATP, 5 mM phosphocreatine, 5 units/ml creatine kinase, 10 mM GTP and 30 mM Ro 20–1724. Reactions were started by the addition of membrane protein, maintained for 10 min at 32°C and stopped with ice-cold 10 mM HCl. After membrane extraction, membranes derived cells were first equilibrated at 4°C for 30 min before AC activity was determined. The amount of cAMP generated was quantitated by radioimmunoassay.

g. Mice Model

Genetically modified mice lacking individual AC isoforms have been described as follows: AC1 (78,83), AC3 (82), AC5 (42), AC6 (74), AC8 (63,79). AC9 is embryonic lethal (82).           

Acknowledgments

I thank John Williams, Sohail Husain and Fred Gorelick for their valuable insights in preparing this molecule page.

4. References 

  1. Akiyama T, Hirohata Y, Okabayashi Y, Imoto I, Otsuki M. Supramaximal CCK and CCh concentrations abolish VIP potentiation by inhibiting adenylyl cyclase activity. Am J Physiol 275: G1202-1208, 1998. PMID: 9815052
  2. Ammer H, Schulz R. Enhanced stimulatory adenylyl cyclase signaling during opioid dependence is associated with a reduction in palmitoylated Gs alpha. Mol Pharmacol 52: 993-999, 1997.  PMID: 9415709
  3. Argent BE GM, Steward MC, Case RM. Cell Physiology of the Pancreatic Ducts. In: Johnson LR, editor. Physiology of the Gastrointestinal Tract. 5th ed. Amsterdam: Elseiver. pp. 1399-1423, 2012.
  4. Bauduin H, Stock C, Launay JF, Vincent D, Potvliege P, Grenier JF. On the secretagogue effect of dibutyryl cyclic AMP in the rat exocrine pancreas. Pflugers Arch 372: 69-76, 1977. PMID: 22842
  5. Beazely MA, Watts VJ. Regulatory properties of adenylate cyclases type 5 and 6: A progress report. Eur J Pharmacol 535: 1-12, 2006. PMID: 16527269
  6. Boden G, Sivitz MC, Owen OE, Essa-Koumar N, Landor JH. Somatostatin suppresses secretin and pancreatic exocrine secretion. Science 190: 163-165, 1975. PMID: 1166308
  7. Burnham DB, McChesney DJ, Thurston KC, Williams JA. Interaction of cholecystokinin and vasoacive intestinal polypeptide on function of mouse pancreatic acini in vitro. J Physiol 349: 475-482, 1984. PMID: 6204039
  8. Burnham DB, Munowitz P, Hootman SR, Williams JA. Regulation of protein phosphorylation in pancreatic acini. Distinct effects of Ca2+ ionophore A23187 and 12-O-tetradecanoylphorbol 13-acetate. Biochem J 235: 125-131, 1986. PMID: 2427068
  9. Burnham DB, Sung CK, Munowitz P, Williams JA. Regulation of protein phosphorylation in pancreatic acini by cyclic AMP-mediated secretagogues: interaction with carbamylcholine. Biochim Biophys Acta 969: 33-39, 1988. PMID: 2450590
  10. Chandrasekar B, Korc M. Basic fibroblast growth factor is a calcium-mobilizing secretagogue in rat pancreatic acini. Biochem Biophys Res Commun 177: 166-170, 1991. PMID: 1710445
  11. Chaudhuri A, Husain SZ, Kolodecik TR, Grant WM, Gorelick FS. Cyclic AMP-dependent protein kinase and Epac mediate cyclic AMP responses in pancreatic acini. Am J Physiol Gastrointest Liver Physiol 292: G1403-1410, 2007. PMID: 17234888
  12. Chaudhuri A, Kolodecik TR, Gorelick FS. Effects of increased intracellular cAMP on carbachol-stimulated zymogen activation, secretion, and injury in the pancreatic acinar cell. Am J Physiol Gastrointest Liver Physiol 288: G235-243, 2005. PMID: 15458924
  13. Clement N, Glorian M, Raymondjean M, Andreani M, Limon I. PGE2 amplifies the effects of IL-1beta on vascular smooth muscle cell de-differentiation: a consequence of the versatility of PGE2 receptors 3 due to the emerging expression of adenylyl cyclase 8. J Cell Physiol 208: 495-505, 2006. PMID: 16741924
  14. Collen MJ, Sutliff VE, Pan GZ, Gardner JD. Postreceptor modulation of action of VIP and secretin on pancreatic enzyme secretion by secretagogues that mobilize cellular calcium. AmJPhysiol 242: G423-G428, 1982. PMID: 6175231
  15. Cooper DM, Mons N, Karpen JW. Adenylyl cyclases and the interaction between calcium and cAMP signalling. Nature 374: 421-424, 1995. PMID: 7700350
  16. Creutzfeldt W, Foelsch UR. Effect of secretin and VIP on isolated pancreatic duct fragments in vitro. Endocrinol Jpn 27 Suppl 1: 59-63, 1980. PMID: 6262064
  17. Cumbay MG, Watts VJ. Novel regulatory properties of human type 9 adenylate cyclase. J Pharmacol Exp Ther 310: 108-115, 2004. PMID: 14996950
  18. Cumbay MG, Watts VJ. Galphaq potentiation of adenylate cyclase type 9 activity through a Ca2+/calmodulin-dependent pathway. Biochem Pharmacol 69: 1247-1256, 2005. PMID: 15794946
  19. Defer N, Best-Belpomme M, Hanoune J. Tissue specificity and physiological relevance of various isoforms of adenylyl cyclase. Am J Physiol Renal Physiol 279: F400-416, 2000. PMID: 10966920
  20. Dehaye JP, Gillard M, Poloczek P, Stievenart M, Winand J, Christophe J. Effects of forskolin on adenylate cyclase activity and amylase secretion in the rat exocrine pancreas. J Cyclic Nucleotide Protein Phosphor Res 10: 269-280, 1985.  PMID: 2410466
  21. Deschodt-Lanckman M, Robberecht P, Pector JC, Christophe J. Effects of somatostatin on pancreatic exocrine function. Interaction with secretin. Arch Int Physiol Biochim 83: 960-961, 1975. PMID: 58620
  22. Dessauer CW Kinetic analysis of the action of P-site analogs. Methods Enzymol 345: 112-126, 2002. PMID: 11665599
  23. Dessauer CW, Tesmer JJ, Sprang SR, Gilman AG. The interactions of adenylate cyclases with P-site inhibitors. Trends Pharmacol Sci 20: 205-210, 1999.  PMID: 10354616
  24. Efendiev R, Samelson BK, Nguyen BT, Phatarpekar PV, Baameur F, Scott JD, Dessauer CW. AKAP79 interacts with multiple adenylyl cyclase (AC) isoforms and scaffolds AC5 and -6 to alpha-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) receptors. J Biol Chem 285: 14450-14458, 2010. PMID: 20231277
  25. Folsch UR, Fischer H, Soling HD, Creutzfeldt W. Effects of gastrointestinal hormones and carbamylcholine on cAMP accumulation in isolated pancreatic duct fragments from the rat. Digestion 20: 277-292, 1980. PMID: 6248407
  26. Gao MH, Tang T, Guo T, Miyanohara A, Yajima T, Pestonjamasp K, Feramisco JR, Hammond HK. Adenylyl cyclase type VI increases Akt activity and phospholamban phosphorylation in cardiac myocytes. J Biol Chem 283: 33527-33535, 2008. PMID: 18838385
  27. Gardner JD, Jackson MJ. Regulation of amylase release from dispersed pancreatic acinar cells. J Physiol 270: 439-454, 1977. PMID: 198531
  28. Gardner JD, Korman LY, Walker MD, Sutliff VE. Effects of inhibitors of cyclic nucleotide phosphodiesterase on the actions of vasoactive intestinal peptide and secretin on pancreatic acini. Am J Physiol 242: G547-551, 1982. PMID: 6178297
  29. Gardner JD, Rottman AJ. Action of cholera toxin on dispersed acini from guinea pig pancreas. Biochim Biophys Acta 585: 250-265, 1979.  PMID: 222350
  30. Gardner JD, Sutliff VE, Walker MD, Jensen RT. Effects of inhibitors of cyclic nucleotide phosphodiesterase on actions of cholecystokinin, bombesin, and carbachol on pancreatic acini. AmJPhysiol 245: G676-G680, 1983. PMID: 6195928
  31. Garry DJ, Garry MG, Williams JA, Mahoney WC, Sorenson RL. Effects of islet hormones on amylase secretion and localization of somatostatin binding sites. Am J Physiol 256: G897-904, 1989. PMID: 2470260
  32. Gunther R, Carstens OC, Schmidt WE, Folsch UR. Transient agonist-induced regulation of the cholecystokinin-A and cholecystokinin-B receptor mRNA levels in rat pancreatic acinar AR42J cells. Pancreatology 3: 47-54, 2003. PMID: 12649564
  33. Heisler S. Forskolin potentiates calcium-dependent amylase secretion from rat pancreatic acinar cells. Can J Physiol Pharmacol 61: 1168-1176, 1983.  PMID: 6196099
  34. Heisler S, Grondin G, Forget G. The effect of various secretagogues on accumulation of cyclic AMP and secretion of alpha-amylase from rat exocrine pancreas. Life Sci 14: 631-639, 1974. PMID: 4363006
  35. Ito T, Hou W, Katsuno T, Igarashi H, Pradhan TK, Mantey SA, Coy DH, Jensen RT. Rat and guinea pig pancreatic acini possess both VIP(1) and VIP(2) receptors, which mediate enzyme secretion. Am J Physiol Gastrointest Liver Physiol 278: G64-74, 2000. PMID: 10644563
  36. Johnson RA, Desaubry L, Bianchi G, Shoshani I, Lyons E Jr, Taussiq R, Watson PA, Cali JJ, Krupinski J, Pieroni JP, Iyengar R. Isozyme-dependent sensitivity of adenylyl cyclases to P-site-mediated inhibition by adenine nucleosides and nucleoside 3'-polyphosphates. J Biol Chem 272: 8962-8966, 1997.  PMID: 9083018
  37. Kimura T, Imamura K, Eckhardt L, Schulz I. Ca2+-, phorbol ester-, and cAMP-stimulated enzyme secretion from permeabilized rat pancreatic acini. Am J Physiol 250: G698-708, 1986.  PMID: 2422955
  38. Kitagawa M, Naruse S, Ishiguro H, Hayakawa T, Nokihara K. The effect of pituitary adenylate cyclase activating polypeptide (PACAP) on amylase secretion from guinea pig pancreatic acini. Biomed Pept Proteins Nucleic Acids 1: 73-76, 1995.  PMID: 9346857
  39. Konturek SJ, Tasler J, Obtulowicz W, Coy DH, Schally AV. Effect of growth hormone-release inhibiting hormone on hormones stimulating exocrine pancreatic secretion. J Clin Invest 58: 1-6, 1976.  PMID: 932201
  40. Krupinski J, Coussen F, Bakalyar HA, Tang WJ, Feinstein PG, Orth K, Slaughter C, Reed RR, Gilman AG. Adenylyl cyclase amino acid sequence: possible channel- or transporter-like structure. Science 244: 1558-1564, 1989. PMID: 2472670
  41. Larose L, Leclerc L, Asselin J, Ruel S, Morisset J. Muscarinic cholinergic induced secretin subsensitivity in rat isolated pancreatic acini. Effects on amylase release, cyclic adenosine monophosphate and inositol phosphate formation. Pancreas 4: 71-78, 1989. PMID: 2470085
  42. Lee KW, Hong JH, Choi IY, Che Y, Lee JK, Yang SD, Song CW, Kang HS, Lee JH, Noh JS, Shin HS, Han PL. Impaired D2 dopamine receptor function in mice lacking type 5 adenylyl cyclase. J Neurosci 22: 7931-7940, 2002. PMID: 12223546
  43. Lefkimmiatis K, Srikanthan M, Maiellaro I, Moyer MP, Curci S, Hofer AM. Store-operated cyclic AMP signalling mediated by STIM1. Nat Cell Biol 11: 433-442, 2009. PMID: 19287379
  44. Li Y, Chen L, Kass RS, Dessauer CW. The A-kinase anchoring protein Yotiao facilitates complex formation between adenylyl cyclase type 9 and the IKs potassium channel in heart. J Biol Chem 287: 29815-29824, 2012. PMID: 22778270
  45. Long BW, Gardner JD. Effects of cholecystokinin on adenylate cyclase activity in dispersed pancreatic acinar cells. Gastroenterology 73: 1008-1014, 1977. PMID: 198331
  46. Lu Z, Kolodecik TR, Karne S, Nyce M, Gorelick F. Effect of ligands that increase cAMP on caerulein-induced zymogen activation in pancreatic acini. Am J Physiol Gastrointest Liver Physiol 285: G822-828, 2003. PMID: 12881228
  47. Marino CR, Leach SD, Schaefer JF, Miller LJ, Gorelick FS. Characterization of cAMP-dependent protein kinase activation by CCK in rat pancreas. FEBS Lett 316: 48-52, 1993.  PMID: 7678554
  48. Matsushita K, Okabayashi Y, Hasegawa H, Koide M, Kido Y, Okutani T, Sugimoto Y, Kasuga M. In vitro inhibitory effect of somatostatin on secretin action in exocrine pancreas of rats. Gastroenterology 104: 1146-1152, 1993. PMID: 7681794
  49. Mayo KE, Miller LJ, Bataille D, Dalle S, Goke B, Thorens B, Drucker DJ. International Union of Pharmacology. XXXV. The glucagon receptor family. Pharmacol Rev 55: 167-194, 2003. PMID: 12615957
  50. Nelson EJ, Hellevuo K, Yoshimura M, Tabakoff B. Ethanol-induced phosphorylation and potentiation of the activity of type 7 adenylyl cyclase. Involvement of protein kinase C delta. J Biol Chem 278: 4552-4560, 2003. PMID: 12454008
  51. Ohnishi H, Mine T, Kojima I. Inhibition by somatostatin of amylase secretion induced by calcium and cyclic AMP in rat pancreatic acini. Biochem J 304 ( Pt 2): 531-536, 1994. PMID: 7528010
  52. Olinger EJ, Gardner JD. Action of VIP and secretin on adenylate cyclase activity in acinar cells from guinea pig pancreas. Gastroenterology 77: 704-713, 1979. PMID: 223939
  53. Orabi AI, Shah AU, Muili K, Luo Y, Mahmood SM, Ahmad A, Reed A, Husain SZ. Ethanol enhances carbachol-induced protease activation and accelerates Ca2+ waves in isolated rat pancreatic acini. J Biol Chem 286: 14090-14097, 2011. PMID: 21372126
  54. O'Sullivan AJ, Jamieson JD. Protein kinase A modulates Ca(2+)- and protein kinase C-dependent amylase release in permeabilized rat pancreatic acini. Biochem J 287 ( Pt 2): 403-406, 1992. PMID: 1280101
  55. Peikin SR, Rottman AJ, Batzri S, Gardner JD. Kinetics of amylase release by dispersed acini prepared from guinea pig pancreas. Am J Physiol 235: E743-749, 1978.  PMID: 736135
  56. Perides G, Sharma A, Gopal A, Tao X, Dwyer K, Ligon B, Steer ML. Secretin differentially sensitizes rat pancreatic acini to the effects of supramaximal stimulation with caerulein. Am J Physiol Gastrointest Liver Physiol 289: G713-721, 2005. PMID: 15920015
  57. Premont RT, Matsuoka I, Mattei MG, Pouille Y, Defer N, Hanoune J. Identification and characterization of a widely expressed form of adenylyl cyclase. J Biol Chem 271: 13900-13907, 1996.  PMID: 8662814
  58. Robberecht P, Deschodt-Lanckman M, Lammens M, De Neff P, Christophe J. "In vitro" effects of secretin and vasoactive intestinal polypeptide on hydrolase secretion and cylic AMP levels in the pancreas of five animal species. A comparison with caerulein. Gastroenterol Clin Biol 1: 519-525, 1977. PMID: 196970
  59. Rutten WJ, de Pont JJ, Bonting SL. Adenylate cyclase in the rat pancreas properties and stimulation by hormones. Biochim Biophys Acta 274: 201-213, 1972. PMID: 4625504
  60. Sabbatini ME, Chen X, Ernst SA, Williams JA. Rap1 activation plays a regulatory role in pancreatic amylase secretion. J Biol Chem 283: 23884-23894, 2008.  PMID: 18577515
  61. Sabbatini ME, D'Alecy L, Lentz SI, Tang T, Williams JA. Adenylyl cyclase 6 mediates the action of cyclic AMP-dependent secretagogues in mouse pancreatic exocrine cells via PKA pathway activation. J Physiol, 2013. PMID: 23753526
  62. Sadana R, Dessauer CWT. Physiological roles for G protein-regulated adenylyl cyclase isoforms: insights from knockout and overexpression studies. Neurosignals 17: 5-22, 2009. PMID: 18948702
  63. Schaefer ML, Wong ST, Wozniak DF, Muglia LM, Liauw JA, Zhua M, Nardi A, Hartman RE, Vogt SK, Luedke CE, Storm DR, Muglia LJ. Altered stress-induced anxiety in adenylyl cyclase type VIII-deficient mice. J Neurosci 20: 4809-4820, 2000. PMID: 10864938
  64. Schafer C, Steffen H, Printz H, Goke B. Effects of synthetic cyclic AMP analogs on amylase exocytosis from rat pancreatic acini. Can J Physiol Pharmacol 72: 1138-1147, 1994. PMID: 7533648
  65. Seamon KB, Daly JW. Forskolin: its biological and chemical properties. Adv Cyclic Nucleotide Protein Phosphorylation Res 20: 1-150, 1986. PMID: 3028083
  66. Shah AU, Grant WM, Latif SU, Mannan ZM, Park AJ, Husain SZ. Cyclic AMP accelerates calcium waves in pancreatic acinar cells. Am J Physiol Gastrointest Liver Physiol 294: G1328-1334, 2008. PMID: 18388188
  67. Simeone DM, Yule DI, Logsdon CD, Williams JA. Ca2+ signaling through secretagogue and growth factor receptors on pancreatic AR42J cells. Regul Pept 55: 197-206, 1995. PMID: 7538685
  68. Singh M. Role of cyclic adenosine monophosphate in amylase release from dissociated rat pancreatic acini. J Physiol 331: 547-555, 1982. PMID: 6185668
  69. Singh P, Asada I, Owlia A, Collins TJ, Thompson JC. Somatostatin inhibits VIP-stimulated amylase release from perifused guinea pig pancreatic acini. Am J Physiol 254: G217-G223, 1988. PMID: 2450469
  70. Smith PA, Case RM. Effects of cholera toxin on cyclic adenosine 3',5'-monophosphate concentration and secretory processes in the exocrine pancreas. Biochim Biophys Acta 399: 277-290, 1975. PMID: 169903
  71. Strazzabosco M, Fiorotto R, Melero S, Glaser S, Francis H, Spirli C, Alpini G. Differentially expressed adenylyl cyclase isoforms mediate secretory functions in cholangiocyte subpopulation. Hepatology 50: 244-252, 2009. PMID: 19444869
  72. Stryjek-Kaminska D, Piiper A, Zeuzem S. EGF inhibits secretagogue-induced cAMP production and amylase secretion by Gi proteins in pancreatic acini. Am J Physiol 269: G676-682, 1995. PMID: 7491958
  73. Sunahara RK, Taussig R (2002) Isoforms of mammalian adenylyl cyclase: multiplicities of signaling. Mol Interv 2: 168-184, 2002. PMID: 14993377
  74. Tang T, Gao MH, Lai NC, Firth AL, Takahashi T, Guo T, Yuan JX, Roth DM, Hammond HK. Adenylyl cyclase type 6 deletion decreases left ventricular function via impaired calcium handling. Circulation 117: 61-69, 2008. PMID: 18071070
  75. Trimble ER, Bruzzone R, Biden TJ, Farese RV. Secretin induces rapid increases in inositol trisphosphate, cytosolic Ca2+ and diacylglycerol as well as cyclic AMP in rat pancreatic acini. Biochem J 239: 257-261, 1986.  PMID: 3028367
  76. Ulrich CD, 2nd, Holtmann M, Miller LJ. Secretin and vasoactive intestinal peptide receptors: members of a unique family of G protein-coupled receptors. Gastroenterology 114: 382-397, 1998. PMID: 9453500
  77. Viguerie N, Tahiri-Jouti N, Esteve JP, Clerc P, Logsdon C, Svoboda M, Susini C, Vaysse N, Ribet A. Functional somatostatin receptors on a rat pancreatic acinar cell line. Am J Physiol 255: G113-120, 1988. PMID: 2898895
  78. Villacres EC, Wu Z, Hua W, Nielsen MD, Watters JJ, Yan C, Beavo J, Storm DR. Developmentally expressed Ca(2+)-sensitive adenylyl cyclase activity is disrupted in the brains of type I adenylyl cyclase mutant mice. J Biol Chem 270: 14352-14357, 1995.  PMID: 7782295
  79. Watson EL, Jacobson KL, Singh JC, Idzerda R, Ott SM, DiJulio DH, Wong ST, Storm DR. The type 8 adenylyl cyclase is critical for Ca2+ stimulation of cAMP accumulation in mouse parotid acini. J Biol Chem 275: 14691-14699, 2000. PMID: 10799557
  80. Wayman GA, Hinds TR, Storm DR. Hormone stimulation of type III adenylyl cyclase induces Ca2+ oscillations in HEK-293 cells. J Biol Chem 270: 24108-24115, 1995.  PMID: 7592612
  81. Willoughby D, Cooper DM. Organization and Ca2+ regulation of adenylyl cyclases in cAMP microdomains. Physiol Rev 87: 965-1010, 2007. PMID: 17615394
  82. Wong ST, Trinh K, Hacker B, Chan GC, Lowe G, Gaggar A, Xia Z, Gold GH, Storm DR. Disruption of the type III adenylyl cyclase gene leads to peripheral and behavioral anosmia in transgenic mice. Neuron 27: 487-497, 2000. PMID: 11055432
  83. Wu ZL, Thomas SA, Villacres EC, Xia Z, Simmons ML, Chavkin C, Palmiter RD, Storm DR. Altered behavior and long-term potentiation in type I adenylyl cyclase mutant mice. Proc Natl Acad Sci USA 92: 220-224, 1995. PMID: 7816821
  84. Yan SZ, Huang ZH, Andrews RK, Tang WJ. Conversion of forskolin-insensitive to forskolin-sensitive (mouse-type IX) adenylyl cyclase. Mol Pharmacol 53: 182-187, 1998.  PMID: 9463474
  85. Zajic G, Schacht J. Cytochemical demonstration of adenylate cyclase with strontium chloride in the rat pancreas. J Histochem Cytochem 31: 25-28, 1983. PMID: 6187800
  86. Zhou ZC, Gardner JD, Jensen RT. Interaction of peptides related to VIP and secretin with guinea pig pancreatic acini. Am J Physiol 256: G283-290, 1989.  PMID: 2465694