Cyclic AMP accumulation induces a rapid desensitization of the cyclic AMP-dependent protein kinase in mouse striatal neurons.
Striatal neurons from the mouse brain embryo grown in primary culture express high levels of cyclic AMP (cAMP)-dependent protein kinase (PKA) activity. To study the modulation of PKA in intact neurons, a rapid method based on Zn(2+)-protein precipitation was developed. This strategy allowed analysis of the stimulation of PKA under conditions of intracellular cAMP concentration increases. Whereas increases up to 1 microM lead to an activation, large and sustained accumulations of cAMP result in a loss of the enzyme activity. With 8-bromo-cAMP (8-Br-cAMP) at 100 microM, the PKA refractoriness occurs within 2 min. It is rapidly reversible because incubation of treated neurons in fresh medium leads to a complete recovery of PKA activity within 30 min. The decrease in assayable PKA does not involve an activation of phosphatases because the histone dephosphorylation rate is not affected by 8-Br-cAMP treatment. Finally, not only 8-Br-cAMP- but also forskolin- and vasoactive intestinal peptide-induced increases in intracellular cAMP concentration can lead to the PKA desensitization. Altogether, these data unravel a new mechanism of PKA regulation.
Chneiweiss
H
H
INSERM U. 114, Collège de France, Paris.
Cordier
J
J
Glowinski
J
J
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology*; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002352:Carrier Proteins / Q000494:pharmacology; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D003342:Corpus Striatum / Q000201:enzymology*; D000242:Cyclic AMP / Q000378:metabolism* / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D004789:Enzyme Activation; D047908:Intracellular Signaling Peptides and Proteins; D007700:Kinetics; D046911:Macromolecular Substances; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000201:enzymology*; D011494:Protein Kinases / Q000378:metabolism*; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology; D015032:Zinc / Q000378:metabolism
D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D046911:Macromolecular Substances; C015482:protein kinase modulator; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D014660:Vasoactive Intestinal Peptide; D003994:Bucladesine; D004492:Edetic Acid; D000242:Cyclic AMP; D011494:Protein Kinases; D015032:Zinc; D015056:1-Methyl-3-isobutylxanthine