An Aplysia type 4 phosphodiesterase homolog localizes at the presynaptic terminals of Aplysia neuron and regulates synaptic facilitation

Hyungju Park, Jin A. Lee, Changhoon Lee, Min Jeong Kim, Deok Jin Chang, Hyoung Kim, Seung Hee Lee, Yong Seok Lee, Bong Kiun Kaang

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

The cAMP-dependent signaling pathway is critically involved in memory-related synaptic plasticity. cAMP-specific type 4 phosphodiesterases (PDE4) play a role in this process by regulating the cAMP concentration. However, it is unclear how PDE4 is involved in regulating synaptic plasticity. To address this issue in Aplysia sensory-to-motor synapses, we identified a long isoform of the PDE4 homolog in Aplysia kurodai (apPDE), with genetic and biochemical properties similar to those of mammalian PDE4s. Furthermore, apPDE is localized to the membrane and presynaptic region. Both apPDE overexpression and knock-down impaired short- and long-term facilitation, indicating that an appropriate expression level of apPDE in synaptic regions is required for normal synaptic facilitation. By using fluorescence resonance energy transfer-based measurement of in vivo protein kinase A (PKA) activation, we found that the PKA activation by 5-hydroxytryptamine (5-HT) was impaired in both apPDE-overexpressed and knock-down synapses. Analogous to the inhibition of apPDE by RNA interference, chronic rolipram treatment before 5-HT stimulation also impaired the PKA activation by 5-HT, suggesting that regulation of the synaptic cAMP level by PDE4 is critical for normal synaptic facilitation. Together, we suggest that PDE4s localized in the synapses play a critical role in regulating the optimum cAMP level required for normal synaptic plasticity.

Original languageEnglish (US)
Pages (from-to)9037-9045
Number of pages9
JournalJournal of Neuroscience
Volume25
Issue number39
DOIs
StatePublished - Sep 28 2005
Externally publishedYes

Keywords

  • cAMP
  • Fret
  • Memory
  • PDE4
  • Rolipram
  • Synaptic facilitation

ASJC Scopus subject areas

  • Neuroscience(all)

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