Structure, Localization, and Regulation of cGMP-inhibited Phosphodiesterase (PDE3)

cAMP and cGMP mediate biological responses initiated by diverse extracellular signals. By catalyzing hydrolysis of the 3′-5′-phosphodiester bond of cyclic nucleotides, cyclic nucleotide phosphodiesterases (PDEs) 1The abbreviations used are: PDEphosphodiesteraseHSLhormone-sensitive lipasePDE3IKPDE3B insulin-sensitive kinasePI3-Kphosphatidylinositol 3-kinaseIRS-1insulin receptor substrate-1. regulate intracellular concentrations and effects of these second messengers. PDEs include a large group of structurally related enzymes (reviewed in 1Manganiello V.C. Murata T. Taira M. Belfrage P. Degerman E. Arch. Biochem. Biophys. 1995; 322: 1-13Crossref PubMed Scopus (223) Google Scholar, 2Conti M. Nemos G. Sette C. Vicini E. Endocr. Rev. 1995; 16: 370-389Crossref PubMed Scopus (317) Google Scholar, 3Beavo J. Physiol. Rev. 1995; 75: 725-748Crossref PubMed Scopus (1647) Google Scholar). These enzymes belong to at least seven related gene families (PDEs 1-7) (Fig. 1), which differ in their primary structures, affinities for cAMP and cGMP, responses to specific effectors, sensitivities to specific inhibitors, and mechanisms of regulation (1Manganiello V.C. Murata T. Taira M. Belfrage P. Degerman E. Arch. Biochem. Biophys. 1995; 322: 1-13Crossref PubMed Scopus (223) Google Scholar, 2Conti M. Nemos G. Sette C. Vicini E. Endocr. Rev. 1995; 16: 370-389Crossref PubMed Scopus (317) Google Scholar, 3Beavo J. Physiol. Rev. 1995; 75: 725-748Crossref PubMed Scopus (1647) Google Scholar). Most families are comprised of more than one gene; 14 different PDE genes have been identified. Within different families, tissue-specific mRNAs are generated from the same gene by the use of different transcription initiation sites or by alternative mRNA splicing. Although some aspects of different PDE families will be discussed, this review emphasizes the PDE3 family, including structure-function information and regulation of the adipocyte PDE3, which plays a key role in the antilipolytic action of insulin. phosphodiesterase hormone-sensitive lipase PDE3B insulin-sensitive kinase phosphatidylinositol 3-kinase insulin receptor substrate-1. Mammalian PDEs share a common structural organization, with a conserved catalytic core (∼270 amino acids) usually located in the C-terminal half (Fig. 1) (4Charbonneau H. Beier N. Walsh K.A. Beavo J.A. Proc. Natl. Acad. Sci. U. S. A. 1986; 83: 9308-9312Crossref PubMed Scopus (112) Google Scholar). This region is much more similar within an individual PDE family (>80% amino acid identity) than between different PDE families (∼25-40% identity) (1Manganiello V.C. Murata T. Taira M. Belfrage P. Degerman E. Arch. Biochem. Biophys. 1995; 322: 1-13Crossref PubMed Scopus (223) Google Scholar, 2Conti M. Nemos G. Sette C. Vicini E. Endocr. Rev. 1995; 16: 370-389Crossref PubMed Scopus (317) Google Scholar, 3Beavo J. Physiol. Rev. 1995; 75: 725-748Crossref PubMed Scopus (1647) Google Scholar, 4Charbonneau H. Beier N. Walsh K.A. Beavo J.A. Proc. Natl. Acad. Sci. U. S. A. 1986; 83: 9308-9312Crossref PubMed Scopus (112) Google Scholar). The catalytic core is thought to contain common structural elements important for hydrolysis of the cyclic nucleotide phosphodiester bond, as well as family-specific determinants responsible for differences in substrate affinities and inhibitor sensitivities among the different gene families. It contains a PDE-specific sequence motif, HD(X)2H(X4)N, and two consensus Zn2+-binding domains, the second of which overlaps the PDE motif (3Beavo J. Physiol. Rev. 1995; 75: 725-748Crossref PubMed Scopus (1647) Google Scholar, 5Francis S.H. Colbran J.L. McAllister-Lucas L.M. Corbin J.D. J. Biol. Chem. 1994; 269: 22477-22480Abstract Full Text PDF PubMed Google Scholar). PDE5 contains tightly bound Zn2+, which supports catalytic activity (5Francis S.H. Colbran J.L. McAllister-Lucas L.M. Corbin J.D. J. Biol. Chem. 1994; 269: 22477-22480Abstract Full Text PDF PubMed Google Scholar). The precise role of Zn2+ or other divalent cations in catalytic function of other PDEs has not been defined. Mutagenesis of the first histidine of the PDE sequence motif abolished activity of a recombinant PDE4 expressed in Escherichia coli (6Jin S.-L. Swinnen J.V. Conti M. J. Biol. Chem. 1992; 267: 18929-18939Abstract Full Text PDF PubMed Google Scholar). Histidine- and sulfhydryl-modifying reagents inhibited PDE3 activity (7Omburo G.A. Brickus T. Ghazaleh F. Colman R.W. Arch. Biochem. Biophys. 1995; 323: 1-5Crossref PubMed Scopus (25) Google Scholar). The widely divergent N-terminal portions of PDEs (Fig. 1) contain determinants that confer regulatory properties specific to the different gene families, e.g. calmodulin-binding domains (PDE1); two non-catalytic cyclic nucleotide-binding domains (PDEs 2, 5, and 6); N-terminal membrane-targeting (PDE4) or hydrophobic membrane-association (PDE3) domains; and calmodulin (PDE1)-, cyclic AMP (PDEs 1, 3, and 4)-, and cGMP (PDE5)-dependent protein kinase phosphorylation sites, etc. (Fig. 1) (1Manganiello V.C. Murata T. Taira M. Belfrage P. Degerman E. Arch. Biochem. Biophys. 1995; 322: 1-13Crossref PubMed Scopus (223) Google Scholar, 2Conti M. Nemos G. Sette C. Vicini E. Endocr. Rev. 1995; 16: 370-389Crossref PubMed Scopus (317) Google Scholar, 3Beavo J. Physiol. Rev. 1995; 75: 725-748Crossref PubMed Scopus (1647) Google Scholar). Most cells contain representatives of several PDE families in different amounts, proportions, and subcellular locations (1Manganiello V.C. Murata T. Taira M. Belfrage P. Degerman E. Arch. Biochem. Biophys. 1995; 322: 1-13Crossref PubMed Scopus (223) Google Scholar, 2Conti M. Nemos G. Sette C. Vicini E. Endocr. Rev. 1995; 16: 370-389Crossref PubMed Scopus (317) Google Scholar, 3Beavo J. Physiol. Rev. 1995; 75: 725-748Crossref PubMed Scopus (1647) Google Scholar). In some instances a specific PDE regulates a unique cellular function, e.g. photoreceptor PDE6 in cGMP-dependent initiation of visual transduction. In individual cells, different PDEs, with their different responses to regulatory signals, participate in integrating multiple inputs in the complex modulation and termination of cyclic nucleotide signals and responses, e.g. their magnitude and duration, their functional and spatial compartmentation, and their attenuation by short-term feedback or long-term desensitization. PDE3s, purified to apparent homogeneity from a variety of tissues, can be distinguished from other PDEs by their high affinities for both cAMP and cGMP, with Km values in the range of 0.1-0.8 μM and Vmax for cAMP 4-10 times higher than that for cGMP (1Manganiello V.C. Murata T. Taira M. Belfrage P. Degerman E. Arch. Biochem. Biophys. 1995; 322: 1-13Crossref PubMed Scopus (223) Google Scholar, 2Conti M. Nemos G. Sette C. Vicini E. Endocr. Rev. 1995; 16: 370-389Crossref PubMed Scopus (317) Google Scholar, 3Beavo J. Physiol. Rev. 1995; 75: 725-748Crossref PubMed Scopus (1647) Google Scholar, 8Manganiello V.C. Smith C.J. Degerman E. Belfrage P. Beavo J.A. Houslay M.D. Cyclic Nucleotide Phosphodiesterases: Structure, Regulation, and Drug Action. John Wiley and Sons, Chichester, UK1990: 87-116Google Scholar). PDE3 is for several reasons often referred to as the cGMP-inhibited PDE. When different PDEs were first identified, two types (now classified as PDE3 and PDE4 (3Beavo J. Physiol. Rev. 1995; 75: 725-748Crossref PubMed Scopus (1647) Google Scholar)) that exhibited a high affinity for cAMP were isolated from various tissues. PDE3, but not PDE4, exhibited a high affinity for both cAMP and cGMP. As might be predicted from their Km values, cAMP and cGMP were mutually competitive substrates for PDE3. In contrast, cGMP was hydrolyzed poorly by, and did not inhibit, PDE4. Thus, PDE3 was called the cGMP-inhibited PDE to distinguish it from PDE4. In fact, some biological effects of endogenous cGMP may be mediated by inhibition of PDE3, which results in increased cAMP and activation of cAMP-dependent protein kinase (protein kinase A) (1Manganiello V.C. Murata T. Taira M. Belfrage P. Degerman E. Arch. Biochem. Biophys. 1995; 322: 1-13Crossref PubMed Scopus (223) Google Scholar, 2Conti M. Nemos G. Sette C. Vicini E. Endocr. Rev. 1995; 16: 370-389Crossref PubMed Scopus (317) Google Scholar, 3Beavo J. Physiol. Rev. 1995; 75: 725-748Crossref PubMed Scopus (1647) Google Scholar). For example, in rabbit platelets (9Maurice D. Haslam R. Mol. Pharmacol. 1990; 37: 671-681PubMed Google Scholar), mouse thymocytes (10Marcoz P. Prigent A.F. Lagarde M. Nemoz G. Mol. Pharmacol. 1993; 44: 1027-1035PubMed Google Scholar), and human atrial and frog ventricular myocytes (11Kirstein M. Rivet-Bastide M. Hatem S. Benardeau A. Mercadier J.-J. Fischmeister R. J. Clin. Invest. 1995; 95: 794-802Crossref PubMed Scopus (166) Google Scholar), nitrovasodilators (which release nitric oxide and activate guanylyl cyclase) increase cAMP, at least in part, by increasing cGMP, which inhibits PDE3. PDE2 isoforms, which are allosterically activated by cGMP, also serve as a locus for “cross-talk” between cAMP and cGMP signaling systems. PDE2 is highly concentrated in bovine adrenal glomerulosa cells where atrial natriuretic factor inhibits cAMP-stimulated aldosterone biosynthesis, at least in part, by stimulating guanylyl cyclase and increasing cGMP, which activates PDE2 leading to a decrease in cAMP and protein kinase A activity (12MacFarland R.T. Zelus B.D. Beavo J.A. J. Biol. Chem. 1991; 266: 136-142Abstract Full Text PDF PubMed Google Scholar). PDE3 isoforms are also characterized by their sensitivity to several specific inhibitors and drugs, including cilostamide, enoximone, and lixazinone (reviewed in 13Beavo J.A. Reifsnyder D.H. Trends Pharmacol. 1990; 11: 150-155Abstract Full Text PDF PubMed Scopus (827) Google Scholar–15Weishaar R.E. Cain M.H. Bristol J.A. J. Med. Chem. 1985; 28: 537-545Crossref PubMed Scopus (246) Google Scholar), compounds relatively selective for PDE3, with Ki and IC50 values at least 10-100-fold lower for PDE3 than for other PDE families. The availability of family-specific PDE inhibitors, especially for PDEs 3, 4, and 5 (Fig. 1), has facilitated understanding of functions of individual PDEs in regulating specific cyclic nucleotide-mediated processes, e.g. PDE3s in regulation of certain cAMP-modulated processes, including stimulation of myocardial contractility, inhibition of platelet aggregation, relaxation of vascular and airway smooth muscle, and inhibition of proliferation of T-lymphocytes and cultured vascular smooth muscle cells (13Beavo J.A. Reifsnyder D.H. Trends Pharmacol. 1990; 11: 150-155Abstract Full Text PDF PubMed Scopus (827) Google Scholar, 14Thompson W.J. Pharmacol. & Ther. 1991; 57: 13-33Crossref Scopus (249) Google Scholar, 15Weishaar R.E. Cain M.H. Bristol J.A. J. Med. Chem. 1985; 28: 537-545Crossref PubMed Scopus (246) Google Scholar, 16Komas N. Movsesian M. Kedev S. Degerman E. Belfrage P. Manganiello V.C. Schudt C. Dent G. Rabe K.F. Handbook of Pharmacology: Phosphodiesterase Inhibitors. Academic Press, London1996: 89-109Google Scholar, 17Manganiello V.C. Taira M. Degerman E. Belfrage P. Cell. Signalling. 1995; 7: 445-455Crossref PubMed Scopus (122) Google Scholar). The pharmaceutical industry has exhibited considerable interest in developing specific inhibitors of individual PDE families and subfamilies as therapeutic agents to replace widely used but nonselective PDE inhibitors such as theophylline. That subject is, however, beyond the scope of this review. A third important general characteristic of PDE3s (discussed in more detail below) involves their phosphorylation and short-term activation in response to insulin as well as to agents that increase cAMP in adipocytes, hepatocytes, and platelets (reviewed in 18Degerman E. Leroy M.J. Taira M. Belfrage P. Manganiello V.C. LeRoith D. Olefsky J. Taylor S. Diabetes Mellitus, A Clinical and Fundamental Textbook. Lippincott Raven, Philadelphia, PA1996: 197-204Google Scholar). Other PDEs, in addition to PDE3, are also regulated by phosphorylation (1Manganiello V.C. Murata T. Taira M. Belfrage P. Degerman E. Arch. Biochem. Biophys. 1995; 322: 1-13Crossref PubMed Scopus (223) Google Scholar, 2Conti M. Nemos G. Sette C. Vicini E. Endocr. Rev. 1995; 16: 370-389Crossref PubMed Scopus (317) Google Scholar, 3Beavo J. Physiol. Rev. 1995; 75: 725-748Crossref PubMed Scopus (1647) Google Scholar). For example, phosphorylation of PDE1A by Ca2+/calmodulin-dependent protein kinase or PDE1B by protein kinase A reduces affinity of both PDE1 isoforms for calmodulin. Binding of cGMP to non-catalytic binding sites in the regulatory domain of PDE5 enhances phosphorylation of PDE5 by cGMP-dependent protein kinase (protein kinase G). Phosphorylation of γ-inhibitory subunits of PDE6 by protein kinase C alters their affinity for the PDE6αβ catalytic subunits. Effects of phosphorylation on activities of PDEs 1, 5, and 6 in intact cells have not been documented (1Manganiello V.C. Murata T. Taira M. Belfrage P. Degerman E. Arch. Biochem. Biophys. 1995; 322: 1-13Crossref PubMed Scopus (223) Google Scholar, 2Conti M. Nemos G. Sette C. Vicini E. Endocr. Rev. 1995; 16: 370-389Crossref PubMed Scopus (317) Google Scholar, 3Beavo J. Physiol. Rev. 1995; 75: 725-748Crossref PubMed Scopus (1647) Google Scholar). A PDE4 isoform is phosphorylated and activated in response to hormones that increase cAMP in intact cells and by protein kinase A in vitro (1Manganiello V.C. Murata T. Taira M. Belfrage P. Degerman E. Arch. Biochem. Biophys. 1995; 322: 1-13Crossref PubMed Scopus (223) Google Scholar, 2Conti M. Nemos G. Sette C. Vicini E. Endocr. Rev. 1995; 16: 370-389Crossref PubMed Scopus (317) Google Scholar, 3Beavo J. Physiol. Rev. 1995; 75: 725-748Crossref PubMed Scopus (1647) Google Scholar). Feedback regulation of both PDE3 and PDE4 activities by cAMP-dependent phosphorylation is likely to be central to intracellular mechanisms for regulating the magnitude and duration of cAMP signals and responses and desensitization to hormone signals (2Conti M. Nemos G. Sette C. Vicini E. Endocr. Rev. 1995; 16: 370-389Crossref PubMed Scopus (317) Google Scholar). cDNAs for two PDE3 isoforms (recently classified as PDE3A and PDE3B, respectively (3Beavo J. Physiol. Rev. 1995; 75: 725-748Crossref PubMed Scopus (1647) Google Scholar)) have been cloned from human (H) and rat (R) libraries (19Meacci E. Taira M. Moos Jr., M. Smith C.J. Movsesian M.A. Degerman E. Belfrage P. Manganiello V.C. Proc. Natl. Acad. Sci. U. S. A. 1992; PubMed Scopus Google Scholar, M. S. J. Taira M. Belfrage P. Manganiello V.C. J. Biol. Chem. 1993; Full Text PDF PubMed Google Scholar). of PDE3A from different and are more similar than are of PDE3A and from the same (Fig. The human isoforms, and are of different genes on and mRNA of and predicted and may be in a tissue-specific different initiation sites in the gene J. H. J. Biol. Chem. 1995; 16: Full Text Full Text PDF Scopus Google Scholar). In and but and cellular of and mRNAs M. S. J. Taira M. Belfrage P. Manganiello V.C. J. Biol. Chem. 1993; Full Text PDF PubMed Google Scholar, E. J. Taira M. Murata T. Manganiello V.C. J. Clin. Invest. 1995; 95: PubMed Scopus Google Scholar). mRNA was in and cells, hepatocytes, and developing mRNA was more in and vascular smooth muscle E. J. Taira M. Murata T. Manganiello V.C. J. Clin. Invest. 1995; 95: PubMed Scopus Google Scholar). The of mRNA in developing rat was mRNA was in and J. Scholar). PDE3B mRNA and activity with adipocyte was in cultured but not Manganiello V.C. M. J. Biol. Chem. Full Text PDF PubMed Google Scholar). platelet PDE3 is a PDE3A isoform E. Moos Jr., M. A. E. Smith S. Belfrage P. Manganiello V.C. Biophys. 1995; Scopus Google Scholar). These and other that PDE3A and likely differences in properties and regulation and may serve of different of the PDE1 family has also been (3Beavo J. Physiol. Rev. 1995; 75: 725-748Crossref PubMed Scopus (1647) Google Scholar). In that of different in mouse and rat PDE1A mRNA is in and portions of the PDE1B mRNA in the region and and in (3Beavo J. Physiol. Rev. 1995; 75: 725-748Crossref PubMed Scopus (1647) Google Scholar). of different representatives of the same PDE family of different in different and of cells (1Manganiello V.C. Murata T. Taira M. Belfrage P. Degerman E. Arch. Biochem. Biophys. 1995; 322: 1-13Crossref PubMed Scopus (223) Google J. Physiol. Rev. 1995; 75: 725-748Crossref PubMed Scopus (1647) Google has important not for regulation of cyclic nucleotide concentrations and their biological effects in specific cells but also in of specific PDEs for therapeutic The structural of PDE3A and is The catalytic domain conserved among PDEs is in the C-terminal half of the PDE3 (Fig. 1) and is by a C-terminal region (Fig. Although the catalytic domains of PDE3A and are an of amino in the which not with in the domains of other PDE families (Fig. 1), in PDE3A and isoforms (Fig. This which PDE3 catalytic domains from of other PDEs and may subfamilies within the PDE3 family, the first Zn2+-binding domains in the catalytic domains of PDEs (5Francis S.H. Colbran J.L. McAllister-Lucas L.M. Corbin J.D. J. Biol. Chem. 1994; 269: 22477-22480Abstract Full Text PDF PubMed Google Scholar, E. Taira M. Moos Jr., M. Smith C.J. Movsesian M.A. Degerman E. Belfrage P. Manganiello V.C. Proc. Natl. Acad. Sci. U. S. A. 1992; PubMed Scopus Google Scholar, M. S. J. Taira M. Belfrage P. Manganiello V.C. J. Biol. Chem. 1993; Full Text PDF PubMed Google Scholar). the acid in PDE3 is in with substrates and inhibitors to be The N-terminal portions of PDE3A and are divergent (Fig. The of is in M. S. J. Taira M. Belfrage P. Manganiello V.C. J. Biol. Chem. 1993; Full Text PDF PubMed Google Scholar). PDE3A and contain hydrophobic membrane-association domains with several predicted and several consensus for phosphorylation by protein kinase A (Fig. In intact rat adipocytes, in a PDE3B is phosphorylated in response to insulin and agents that increase cAMP T. Leroy C. H. Manganiello V.C. Belfrage P. Degerman E. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). A of the properties of and PDE3A and and purified platelet PDE3A that the PDE3 catalytic core the conserved PDE domain some and C-terminal (Fig. that the N-terminal portions of PDE3A and PDE3B isoforms are not for PDE3 catalytic activity or sensitivity to specific PDE3 inhibitors (Fig. and that may be more to inhibition by cGMP than (19Meacci E. Taira M. Moos Jr., M. Smith C.J. Movsesian M.A. Degerman E. Belfrage P. Manganiello V.C. Proc. Natl. Acad. Sci. U. S. A. 1992; PubMed Scopus Google Scholar, E. Moos Jr., M. A. E. Smith S. Belfrage P. Manganiello V.C. Biophys. 1995; Scopus Google Scholar, Degerman E. Taira M. Murata T. Movsesian M. E. Manganiello V.C. Scopus Google Scholar, R. S. J. J. Biol. Chem. 1994; 269: Full Text PDF PubMed Google Scholar). structural determinants in cGMP with PDE3, different of the the IC50 values of a of cGMP for inhibition of cAMP hydrolysis J.D. E. S. Beavo J. Mol. Pharmacol. 1995; Google Scholar). PDE3s are in both and of cells V.C. Smith C.J. Degerman E. Belfrage P. Beavo J.A. Houslay M.D. Cyclic Nucleotide Phosphodiesterases: Structure, Regulation, and Drug Action. John Wiley and Sons, Chichester, UK1990: 87-116Google Scholar). The of PDE3A and cDNAs of (Fig. with of for PDE3 isoforms in adipocyte and E. Smith C.J. H. Manganiello V.C. Belfrage P. Proc. Natl. Acad. Sci. U. S. A. 1990; PubMed Scopus Google Scholar, C.J. J. Manganiello V.C. Movsesian M. Biochem. Biophys. 1993; PubMed Scopus Google Scholar). PDE3 isoforms of and have been purified from of human bovine ventricular and bovine smooth muscle E. Moos Jr., M. A. E. Smith S. Belfrage P. Manganiello V.C. Biophys. 1995; Scopus Google Scholar, A.F. Colman R.W. Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar, Reifsnyder D.H. Beavo J.A. Mol. Pharmacol. 1986; Scholar, A. S. Belfrage P. Manganiello V.C. Degerman E. Biophys. 1992; PubMed Scopus Google Scholar). The N-terminal hydrophobic which contain several predicted are likely to be important in of PDE3s, PDE3B and PDE3A and which contain portions of the hydrophobic were in of cells, the C-terminal catalytic core but the hydrophobic were J. H. J. Biol. Chem. 1995; 16: Full Text Full Text PDF Scopus Google Scholar, Degerman E. Taira M. Murata T. Movsesian M. E. Manganiello V.C. Scopus Google Scholar). PDE3 isoforms are generated by of the membrane-association region or from the use of alternative transcription initiation sites or alternative mRNA is J. H. J. Biol. Chem. 1995; 16: Full Text Full Text PDF Scopus Google Scholar, E. Moos Jr., M. A. E. Smith S. Belfrage P. Manganiello V.C. Biophys. 1995; Scopus Google Scholar, Degerman E. Taira M. Murata T. Movsesian M. E. Manganiello V.C. Scopus Google Scholar, C.J. J. Manganiello V.C. Movsesian M. Biochem. Biophys. 1993; PubMed Scopus Google A. S. Belfrage P. Manganiello V.C. Degerman E. Biophys. 1992; PubMed Scopus Google Scholar). In activation of a PDE3B is a by which insulin release of a important in (Fig. E. Leroy M.J. Taira M. Belfrage P. Manganiello V.C. LeRoith D. Olefsky J. Taylor S. Diabetes Mellitus, A Clinical and Fundamental Textbook. Lippincott Raven, Philadelphia, PA1996: 197-204Google Scholar, H. Manganiello V.C. T. Rev. Physiol. 1994; PubMed Scopus Google C.J. Manganiello V.C. Mol. Pharmacol. Scholar). PDE3 inhibitors such as cilostamide, and the antilipolytic action of insulin H. Degerman E. H. Smith C.J. Manganiello V.C. Belfrage P. Biophys. 1995; PubMed Scopus Google Scholar, S. C. Cell. Signalling. 1992; PubMed Scopus Google Scholar, J. Biol. Chem. 1992; 267: Full Text PDF PubMed Google Scholar). a of cAMP of which activated protein kinase A and insulin inhibited the effects of that were substrates of adipocyte PDE Corbin J.D. J. Biol. Chem. 1985; Full Text PDF PubMed Google Scholar). These that activation of than inhibition of cyclase or activation of protein was central to the antilipolytic action of insulin Corbin J.D. J. Biol. Chem. 1985; Full Text PDF PubMed Google Scholar). The in kinase A activity that PDE3B activation results in and activity of hormone-sensitive lipase leading to hydrolysis of (Fig. E. Leroy M.J. Taira M. Belfrage P. Manganiello V.C. LeRoith D. Olefsky J. Taylor S. Diabetes Mellitus, A Clinical and Fundamental Textbook. Lippincott Raven, Philadelphia, PA1996: 197-204Google Scholar, H. Manganiello V.C. T. Rev. Physiol. 1994; PubMed Scopus Google Scholar, P. J. H. P. Belfrage P. J. P. of Action. Scholar, C.J. Manganiello V.C. Mol. Pharmacol. Scholar). of the rat adipocyte PDE3B by insulin is with phosphorylation of on the amino acid sequence of PDE3B M. S. J. Taira M. Belfrage P. Manganiello V.C. J. Biol. Chem. 1993; Full Text PDF PubMed Google by an protein kinase (Fig. T. Leroy C. H. Manganiello V.C. Belfrage P. Degerman E. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). The phosphatidylinositol 3-kinase inhibitor activation of and of PDE3B, as well as the antilipolytic action of insulin T. M. H. Manganiello V.C. G. Belfrage P. Degerman E. 1994; PubMed Scopus Google Scholar). These results that antilipolytic including such as PDE3B, is regulated activation of (Fig. As also in 3, in rat adipocytes, hormones and agents that increase cAMP, including phosphorylation of and activation of PDE3B, by protein kinase A T. Leroy C. H. Manganiello V.C. Belfrage P. Degerman E. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, E. Smith C.J. H. Manganiello V.C. Belfrage P. Proc. Natl. Acad. Sci. U. S. A. 1990; PubMed Scopus Google Scholar, C.J. Degerman E. Belfrage P. Manganiello V.C. J. Biol. Chem. 1991; 266: Full Text PDF PubMed Google Scholar). phosphorylation and activation of PDE3B the same range as that to activate protein kinase and T. Leroy C. H. Manganiello V.C. Belfrage P. Degerman E. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, E. Smith C.J. H. Manganiello V.C. Belfrage P. Proc. Natl. Acad. Sci. U. S. A. 1990; PubMed Scopus Google Scholar, C.J. Manganiello V.C. Mol. Pharmacol. Scholar, C.J. Degerman E. Belfrage P. Manganiello V.C. J. Biol. Chem. 1991; 266: Full Text PDF PubMed Google Scholar). This regulation of cAMP and may be important in concentrations of cAMP and protein kinase A (Fig. In the of insulin and in which insulin reduces protein kinase A activity and inhibits effects of the two on phosphorylation of and activation of PDE3B are more than E. Smith C.J. H. Manganiello V.C. Belfrage P. Proc. Natl. Acad. Sci. U. S. A. 1990; PubMed Scopus Google Scholar, C.J. Manganiello V.C. Mol. Pharmacol. Scholar, C.J. Degerman E. Belfrage P. Manganiello V.C. J. Biol. Chem. 1991; 266: Full Text PDF PubMed Google Scholar). Thus, in PDE3B, a located in a protein kinase A consensus sequence is phosphorylated in response to or the of both T. Leroy C. H. Manganiello V.C. Belfrage P. Degerman E. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google (Fig. that the antilipolytic action of insulin involves between and of PDE3B and that protein kinase A is in of the and activation of PDE3B (Fig. agents have been to responses to insulin and other J. Biol. Chem. 1994; 269: Full Text PDF PubMed Google Scholar, Proc. Natl. Acad. Sci. U. S. A. 1993; PubMed Scopus Google Scholar, M. P. J. Biol. Chem. 1994; 269: Full Text PDF PubMed Google Scholar). In adipocytes, phosphorylation of insulin receptor results in of to and increased activity (Fig. J. Biol. Chem. 1994; 269: Full Text PDF PubMed Google Scholar). In this and as well as other of the signaling between and be in the insulin and cAMP (Fig. protein and are not in this or in the activation of PDE3B by insulin. As in is C-terminal to the membrane-association domain of This is with of of a PDE3 that was from rat by S. G. J. Biochem. PubMed Scopus Google Scholar). Phosphorylation of might or of the catalytic of rat adipocyte from cells increased PDE activity to the same as that in from cells H. T. J. Biol. Chem. Full Text PDF PubMed Google Scholar). is phosphorylated to a similar in intact with hormones and in PDE3B with and protein kinase A T. Leroy C. H. Manganiello V.C. Belfrage P. Degerman E. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, A. Degerman E. Taira M. E. Smith C.J. Manganiello V.C. Belfrage P. H. J. Biol. Chem. 1994; 269: Full Text PDF PubMed Google Scholar). The phosphorylated in however, is A. Degerman E. Taira M. E. Smith C.J. Manganiello V.C. Belfrage P. H. J. Biol. Chem. 1994; 269: Full Text PDF PubMed Google Scholar), which is not phosphorylated in intact cells T. Leroy C. H. Manganiello V.C. Belfrage P. Degerman E. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). this the of PDE3B in intact cells or of PDE3B with different regulatory in intact and cells is not that PDE3B is located in in to a protein for an adipocyte protein kinase protein M. J.D. 1995; Scopus Google Scholar), in of protein kinase A other signaling to substrates such as In such spatial of PDE3B and the in PDE3B regulation of a of cAMP related to modulation of protein kinase A and the inhibition of the antilipolytic of insulin by PDE3 inhibitors but not by PDE4 inhibitors Manganiello V.C. 1985; PubMed Scopus Google Scholar). In general PDEs may an important role in the functional or spatial of cyclic nucleotide signaling In on regulation of in isolated frog ventricular and Fischmeister J. Fischmeister R. Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google to that protein kinase and PDEs PDE isoforms were not were J. Fischmeister R. Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar). results PDEs as in protein kinase A activation to and of cAMP to of the same In human and rat PDE3, not PDE4, inhibitors insulin this the of PDE3 and PDE4 in different cells or different locations in the same J. M.A. Biochem. Biophys. 1995; PubMed Scopus Google Scholar). activation of PDE3 may be an important in insulin regulation of other cAMP-modulated processes, including and and In the frog stimulation of by or is with activation of PDE and inhibition of Although PDEs have not been specific PDE3 inhibitors, but not PDE4 or PDE5 inhibitors, Mol. 1991; PubMed Scopus Google Scholar). It has been J. Biochem. 1991; PubMed Scopus Google Scholar, E. Houslay M.D. Biochem. J. PubMed Scopus Google that an and cAMP-stimulated PDE3 in and activated in vitro by protein kinase A E. Houslay M.D. Biochem. J. PubMed Scopus Google Scholar)) is important in the effects of insulin Corbin J.D. J. Biol. Chem. 1985; Full Text PDF PubMed Google Scholar). In addition to PDE3, an PDE4 is activated by that multiple PDEs are in insulin M.D. E. Beavo J.A. Houslay M.D. Cyclic Nucleotide Phosphodiesterases: Structure, Regulation, and Drug Action. John Wiley and Sons, Chichester, UK1990: Scholar). In specific PDE3 inhibitors aggregation, that PDE3 is important in platelet function R. G. A. M. Mol. Pharmacol. 1986; Google Scholar). of intact platelets with insulin or that increase cAMP, as well as in vitro with protein kinase A or a purified in phosphorylation and activation of platelet PDE3 A.F. Colman R.W. Proc. Natl. Acad. Sci. U. S. A. PubMed Scopus Google Scholar, H. Reifsnyder D.H. Beavo J.A. J. Biol. Chem. Full Text PDF Google Scholar). As was in E. Smith C.J. H. Manganiello V.C. Belfrage P. Proc. Natl. Acad. Sci. U. S. A. 1990; PubMed Scopus Google Scholar, C.J. Degerman E. Belfrage P. Manganiello V.C. J. Biol. Chem. 1991; 266: Full Text PDF PubMed Google Scholar), activation of the platelet PDE3 by insulin with phosphorylation P. A. Manganiello V.C. Belfrage P. Degerman E. Biochem. Biophys. 1992; PubMed Scopus Google the effects of insulin activation of PDE3 on platelet function are not PDE3 inhibitors myocardial and vascular and airway smooth muscle relaxation (13Beavo J.A. Reifsnyder D.H. Trends Pharmacol. 1990; 11: 150-155Abstract Full Text PDF PubMed Scopus (827) Google Scholar, 14Thompson W.J. Pharmacol. & Ther. 1991; 57: 13-33Crossref Scopus (249) Google Scholar, 15Weishaar R.E. Cain M.H. Bristol J.A. J. Med. Chem. 1985; 28: 537-545Crossref PubMed Scopus (246) Google Scholar, 16Komas N. Movsesian M. Kedev S. Degerman E. Belfrage P. Manganiello V.C. Schudt C. Dent G. Rabe K.F. Handbook of Pharmacology: Phosphodiesterase Inhibitors. Academic Press, London1996: 89-109Google Scholar, 17Manganiello V.C. Taira M. Degerman E. Belfrage P. Cell. Signalling. 1995; 7: 445-455Crossref PubMed Scopus (122) Google Scholar). Reifsnyder D.H. Beavo J.A. Mol. Pharmacol. 1986; and vascular smooth muscle A. S. Belfrage P. Manganiello V.C. Degerman E. Biophys. 1992; PubMed Scopus Google PDE3 isoforms are phosphorylated in vitro by protein kinase is however, the regulation of these enzymes in intact PDE3 isoforms to be including of the different PDE3 in cells and tissues, of mechanisms for regulation of their gene and their structure-function and their role in the action of insulin and agents that increase cAMP and cGMP. more will be understanding mechanisms for regulation of the PDE of individual cells, functional of the different PDEs in and regulating cyclic nucleotide of individual cells, and the of specific PDEs for therapeutic for review and for