Rapid nitric oxide-induced desensitization of the cGMP response is caused by increased activity of phosphodiesterase type 5 paralleled by phosphorylation of the enzyme.
Most of the effects of the signaling molecule nitric oxide (NO) are mediated by cGMP, which is synthesized by soluble guanylyl cyclase and degraded by phosphodiesterases. Here we show that in platelets and aortic tissue, NO led to a biphasic response characterized by a tremendous increase in cGMP (up to 100-fold) in less than 30 s and a rapid decline, reflecting the tightly controlled balance of guanylyl cyclase and phosphodiesterase activities. Inverse to the reported increase in sensitivity caused by NO shortage, concentrating NO attenuated the cGMP response in a concentration-dependent manner. We found that guanylyl cyclase remained fully activated during the entire course of the cGMP response; thus, desensitization was not due to a switched off guanylyl cyclase. However, when intact platelets were incubated with NO and then lysed, enhanced activity of phosphodiesterase type 5 was detected in the cytosol. Furthermore, this increase in cGMP degradation is paralleled by the phosphorylation of phosphodiesterase type 5 at Ser-92. Thus, our data suggest that NO-induced desensitization of the cGMP response is caused by the phosphorylation and subsequent activity increase of phosphodiesterase type 5.
Mullershausen
F
F
Abteilung für Pharmakologie und Toxikologie, Medizinische Fakultät, Ruhr-Universität Bochum, D-44780 Bochum, Germany.
Russwurm
M
M
Thompson
W J
WJ
Liu
L
L
Koesling
D
D
Friebe
A
A
D015106:3',5'-Cyclic-GMP Phosphodiesterases; D000818:Animals; D001011:Aorta; D001792:Blood Platelets / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D015815:Cell Adhesion Molecules / Q000378:metabolism; D006152:Cyclic GMP / Q000096:biosynthesis*; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; D004789:Enzyme Activation; D005978:Glutathione / Q000031:analogs & derivatives* / Q000494:pharmacology; D006162:Guanylate Cyclase / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008840:Microfilament Proteins; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D009569:Nitric Oxide / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009574:Nitro Compounds / Q000494:pharmacology; D010750:Phosphoproteins / Q000378:metabolism; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D010766:Phosphorylation; D051381:Rats; D011921:Rats, Inbred WKY; D000098662:Vasodilator-Stimulated Phosphoprotein
D015815:Cell Adhesion Molecules; D008840:Microfilament Proteins; D020030:Nitric Oxide Donors; D009574:Nitro Compounds; D010750:Phosphoproteins; C116027:S-nitroglutathione; D000098662:Vasodilator-Stimulated Phosphoprotein; D009569:Nitric Oxide; D010727:Phosphoric Diester Hydrolases; D015106:3',5'-Cyclic-GMP Phosphodiesterases; D054706:Cyclic Nucleotide Phosphodiesterases, Type 5; C517381:PDE5A protein, human; C517384:Pde5a protein, rat; D006162:Guanylate Cyclase; D005978:Glutathione; D006152:Cyclic GMP