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Nitric Oxide‐Sensitive Guanylyl Cyclase Activity Inhibition Through Cyclic GMP‐Dependent Dephosphorylation
Author(s) -
Ferrero Rut,
RodríguezPascual Fernando,
MirasPortugal M. Teresa,
Torres Magdalena
Publication year - 2000
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.2000.0752029.x
Subject(s) - soluble guanylyl cyclase , cyclic guanosine monophosphate , cgmp dependent protein kinase , sodium nitroprusside , nitric oxide , dephosphorylation , protein kinase a , zaprinast , phosphorylation , phosphodiesterase , phosphatase , chemistry , signal transduction , cyclic nucleotide , protein phosphatase 1 , atrial natriuretic peptide , protein subunit , endocrinology , biochemistry , biology , enzyme , guanylate cyclase , mitogen activated protein kinase kinase , nucleotide , gene
The soluble form of guanylyl cyclase (sGC) plays a pivotal role in the transduction of inter‐ and intracellular signals conveyed by nitric oxide. Here, a feedback inhibitory mechanism triggered by cyclic guanosine‐3′,5′‐monophosphate (cGMP)‐dependent protein kinase (PKG) activation is described. Preincubation of chromaffin cells with C‐type natriuretic peptide, which increased cGMP levels and activated PKG, or with cGMP‐permeant analogue (which also activates PKG), in the presence of a broad‐spectrum phosphodiesterase inhibitor, resulted in a decrease in subsequent sodium nitroprusside (SNP)‐dependent cGMP elevations. This inhibitory effect was mimicked by activating a protein phosphatase and counteracted by the selective PKG inhibitor KT‐5823 and by different protein phosphatase inhibitors. Immunoprecipitation of sGC from cells submitted to different treatments followed by immunodetection with antiphosphoserine antibodies (clone 4A9) showed changes in phosphorylation levels of the β subunit of sGC, and these changes correlated well with differences in SNP‐elicited cGMP accumulations. Pretreatment of cells with several PKG inhibitors or protein phosphatase inhibitors produced an enhancement of SNP‐stimulated cGMP rises without changing the SNP concentration required to produce half‐maximal or maximal responses. Taken together, these results indicate that the catalytic activity of sGC is closely coupled to the phosphorylation state of its β subunit and that the tonic activity of PKG or its stimulation regulates sGC activity through dephosphorylation of the β subunit.