Dynamics of protein kinase A signaling at the membrane, in the cytosol, and in the nucleus of neurons in mouse brain slices

Nicolas Gervasi, Régine Hepp, Ludovic Tricoire, Jin Zhang, Bertrand Lambolez, Danièle Paupardin-Tritsch, Pierre Vincent

Research output: Contribution to journalArticle

Abstract

The cAMP-dependent protein kinase A (PKA) plays a ubiquitous role in the regulation of neuronal activity, but the dynamics of its activation have been difficult to investigate. We used the genetically encoded fluorescent probe AKAR2 to record PKA activation in the cytosol and the nucleus of neurons in mouse brain slice preparations, whereas the potassium current underlying the slow afterhyperpolarization potential (sAHP) in thalamic intralaminar neurons was used to monitor PKA activation at the membrane. Adenylyl cyclase was stimulated either directly using forskolin or via activation of 5-HT7 receptors. Both stimulations produced a maximal effect on sAHP, whereas in the cytosol, the amplitude of the 5-HT7 receptor-mediated response was half of that after direct adenylyl cyclase stimulation with forskolin. 5-HT7-mediated PKA responses were obtained in 30 s at the membrane, in 2.5 min in the cytosol, and in 13 min in the nucleus. Our results show in morphologically intact mammalian neurons the potential physiological relevance of PKA signal integration at the subcellular level: neuromodulators produce fast and powerful effects on membrane excitability, consistent with a highly efficient functional coupling between adenylyl cyclases, PKA, and target channels. Phosphorylation in the cytosol is slower and of graded amplitude, showing a differential integration of the PKA signal between the membrane and the cytosol. The nucleus integrates these cytosolic signals over periods of tens of minutes, consistent with passive diffusion of the free catalytic subunit of PKA into the nucleus, eventually resulting in a graded modulation of gene expression.

Original languageEnglish (US)
Pages (from-to)2744-2750
Number of pages7
JournalJournal of Neuroscience
Volume27
Issue number11
DOIs
StatePublished - Mar 14 2007

Keywords

  • Cyclic AMP
  • FRET
  • Genetically encoded fluorescent probe
  • Neuromodulation
  • PKA
  • Serotonin

ASJC Scopus subject areas

  • Neuroscience(all)

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    Gervasi, N., Hepp, R., Tricoire, L., Zhang, J., Lambolez, B., Paupardin-Tritsch, D., & Vincent, P. (2007). Dynamics of protein kinase A signaling at the membrane, in the cytosol, and in the nucleus of neurons in mouse brain slices. Journal of Neuroscience, 27(11), 2744-2750. https://doi.org/10.1523/JNEUROSCI.5352-06.2007