![[Feedback]](/icons/banner/feedbackACT.gif){kind=icon}
![[For Subscribers]](/icons/banner/subscriberACT.gif){kind=icon}
![[Archive]](/icons/banner/archiveACT.gif){kind=icon}
![[Search]](/icons/banner/searchACT.gif){kind=icon}
![[Contents]](/icons/banner/tocACT.gif){kind=icon}
|
|
|
|
|
||
Department of Molecular Physiology and Biophysics (J.D.C., M.A.B., J.L.W., A.B., J.K., S.H.F.) and Center for Lung Research, Division of Allergy, Pulmonary and Critical Care Medicine (K.P.K.), Vanderbilt University School of Medicine, Nashville, Tennessee; and Laboratory of Molecular Biology, National Institutes of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland (Y.S.J.H., L.F.S., J.H.H.)
Sildenafil (Viagra) potentiates penile erection by acting as a nonhydrolyzable analog of cGMP and competing with this nucleotide for catalysis by phosphodiesterase-5 (PDE5), but the characteristics of direct binding of radiolabeled sildenafil to PDE5 have not been determined. [3H]Sildenafil binding to PDE5 was retained when filtered through nitrocellulose or glass-fiber membranes. Binding was inhibited by excess sildenafil, 2-(2-methylpyridin-4-yl)methyl-4-(3,4,5-trimethoxyphenyl)-8-(pyrimidin-2-yl)methoxy-1,2-dihydro-1-oxo-2,7-naphthyridine-3-carboxylic acid methyl ester hydrochloride (T-0156), 3-isobutyl-1-methylxanthine, EDTA, or cGMP, but not by cAMP or 5'-GMP. PDE5 was the only [3H]sildenafil binding protein detected in human lung extract. Using purified recombinant PDE5, [3H]sildenafil exchange dissociation yielded two components with t1/2 values of 1 and 14 min and corresponding calculated KD values of 12 and 0.83 nM, respectively. This implied the existence of two conformers of the PDE5 catalytic site. [3H]Sildenafil binding isotherm of PDE5 indicated KD was 8.3 to 13.3 nM, and low cGMP decreased the KD to 4.8 nM but only slightly increased Bmax to a maximum of 0.61 mol/mol-subunit. Results suggest that these effects occur via cGMP binding to the allosteric cGMP binding sites of PDE5. Results imply that by inhibiting PDE5 and thereby increasing cGMP, sildenafil accentuates its own binding affinity for PDE5, which further elevates cGMP. The data also indicate that after physiological elevation, cGMP may directly stimulate the catalytic site by binding to the allosteric cGMP-binding sites of PDE5, thus causing negative feedback on this pathway.
Received November 20, 2002; accepted March 11, 2003.
Address correspondence to: Jackie D. Corbin, 702 Light Hall, Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232-0615. E-mail: jackie.corbin{at}vanderbilt.edu
This article has been cited by other articles:
|
|
 |
|
  S. Vaccari, J. L. Weeks II, M. Hsieh, F. S. Menniti, and M. Conti Cyclic GMP Signaling Is Involved in the Luteinizing Hormone-Dependent Meiotic Maturation of Mouse Oocytes Biol Reprod, September 1, 2009; 81(3): 595 - 604. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 X.-J. Zhang, K. B. Cahill, A. Elfenbein, V. Y. Arshavsky, and R. H. Cote Direct Allosteric Regulation between the GAF Domain and Catalytic Domain of Photoreceptor Phosphodiesterase PDE6 J. Biol. Chem., October 31, 2008; 283(44): 29699 - 29705. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. E. Martinez, C. C. Heikaus, R. E. Klevit, and J. A. Beavo The Structure of the GAF A Domain from Phosphodiesterase 6C Reveals Determinants of cGMP Binding, a Conserved Binding Surface, and a Large cGMP-dependent Conformational Change J. Biol. Chem., September 19, 2008; 283(38): 25913 - 25919. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. P. Bessay, M. A. Blount, R. Zoraghi, A. Beasley, K. A. Grimes, S. H. Francis, and J. D. Corbin Phosphorylation Increases Affinity of the Phosphodiesterase-5 Catalytic Site for Tadalafil J. Pharmacol. Exp. Ther., April 1, 2008; 325(1): 62 - 68. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. W. M. Nausch, J. Ledoux, A. D. Bonev, M. T. Nelson, and W. R. Dostmann Differential patterning of cGMP in vascular smooth muscle cells revealed by single GFP-linked biosensors PNAS, January 8, 2008; 105(1): 365 - 370. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. A. Blount, R. Zoraghi, E. P. Bessay, A. Beasley, S. H. Francis, and J. D. Corbin Conversion of Phosphodiesterase-5 (PDE5) Catalytic Site to Higher Affinity by PDE5 Inhibitors J. Pharmacol. Exp. Ther., November 1, 2007; 323(2): 730 - 737. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. A. Blount, R. Zoraghi, H. Ke, E. P. Bessay, J. D. Corbin, and S. H. Francis A 46-Amino Acid Segment in Phosphodiesterase-5 GAF-B Domain Provides for High Vardenafil Potency over Sildenafil and Tadalafil and Is Involved in Phosphodiesterase-5 Dimerization Mol. Pharmacol., November 1, 2006; 70(5): 1822 - 1831. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 X. Zhang, Q. Feng, and R. H. Cote Efficacy and Selectivity of Phosphodiesterase-Targeted Drugs in Inhibiting Photoreceptor Phosphodiesterase (PDE6) in Retinal Photoreceptors Invest. Ophthalmol. Vis. Sci., September 1, 2005; 46(9): 3060 - 3066. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Musicki, H. C. Champion, R. E. Becker, T. Liu, M. F. Kramer, and A. L. Burnett Erection Capability Is Potentiated by Long-Term Sildenafil Treatment: Role of Blood Flow-Induced Endothelial Nitric-Oxide Synthase Phosphorylation Mol. Pharmacol., July 1, 2005; 68(1): 226 - 232. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Zoraghi, E. P. Bessay, J. D. Corbin, and S. H. Francis Structural and Functional Features in Human PDE5A1 Regulatory Domain That Provide for Allosteric cGMP Binding, Dimerization, and Regulation J. Biol. Chem., March 25, 2005; 280(12): 12051 - 12063. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Huang, T. R. Hinds, S. E. Martinez, C. Doneanu, and J. A. Beavo Molecular Determinants of cGMP Binding to Chicken Cone Photoreceptor Phosphodiesterase J. Biol. Chem., November 12, 2004; 279(46): 48143 - 48151. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 O. Pauvert, S. Bonnet, E. Rousseau, R. Marthan, and J.-P. Savineau Sildenafil alters calcium signaling and vascular tone in pulmonary arteries from chronically hypoxic rats Am J Physiol Lung Cell Mol Physiol, September 1, 2004; 287(3): L577 - L583. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Mullershausen, M. Russwurm, D. Koesling, and A. Friebe In Vivo Reconstitution of the Negative Feedback in Nitric Oxide/cGMP Signaling: Role of Phosphodiesterase Type 5 Phosphorylation Mol. Biol. Cell, September 1, 2004; 15(9): 4023 - 4030. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. A. Blount, A. Beasley, R. Zoraghi, K. R. Sekhar, E. P. Bessay, S. H. Francis, and J. D. Corbin Binding of Tritiated Sildenafil, Tadalafil, or Vardenafil to the Phosphodiesterase-5 Catalytic Site Displays Potency, Specificity, Heterogeneity, and cGMP Stimulation Mol. Pharmacol., July 1, 2004; 66(1): 144 - 152. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C.-B. Zhu, W. A. Hewlett, I. Feoktistov, I. Biaggioni, and R. D. Blakely Adenosine Receptor, Protein Kinase G, and p38 Mitogen-Activated Protein Kinase-Dependent Up-Regulation of Serotonin Transporters Involves Both Transporter Trafficking and Activation Mol. Pharmacol., June 1, 2004; 65(6): 1462 - 1474. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Zoraghi, J. D. Corbin, and S. H. Francis Properties and Functions of GAF Domains in Cyclic Nucleotide Phosphodiesterases and Other Proteins Mol. Pharmacol., February 1, 2004; 65(2): 267 - 278. [Full Text] [PDF]
|
|
|
|
 |
|
 J. D. Corbin and S. H. Francis Molecular Biology and Pharmacology of PDE-5--Inhibitor Therapy for Erectile Dysfunction J Androl, November 1, 2003; 24(6_suppl): S38 - S41. [Full Text] [PDF]
|
|
|
|
 |
|
 S. D. Rybalkin, C. Yan, K. E. Bornfeldt, and J. A. Beavo Cyclic GMP Phosphodiesterases and Regulation of Smooth Muscle Function Circ. Res., August 22, 2003; 93(4): 280 - 291. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. Manganiello Cyclic Nucleotide Phosphodiesterase 5 and Sildenafil: Promises Realized Mol. Pharmacol., June 1, 2003; 63(6): 1209 - 1211. [Full Text] [PDF]
|
|
 |
 |
 |
|
 |
 |
 |
