N termini of apPDE4 isoforms are responsible for targeting the isoforms to different cellular membranes

Learn Mem. 2010 Sep 2;17(9):469-79. doi: 10.1101/lm.1899410. Print 2010 Sep.

Abstract

Phosphodiesterases (PDEs) are known to play a key role in the compartmentalization of cAMP signaling; however, the molecular mechanisms underlying intracellular localization of different PDE isoforms are not understood. In this study, we have found that each of the supershort, short, and long forms of apPDE4 showed distinct localization in the cytoplasm, plasma membrane, and both plasma membrane and presynaptic terminals, respectively. The N-terminal 20 amino acids of the long form of apPDE4 were involved in presynaptic terminal targeting by binding to several lipids. In addition, the N terminus of the short form of apPDE4 bound to several lipids including phosphoinositols, thereby targeting the plasma membrane. Overexpression of the long and the short forms, but not the supershort form attenuated 5-HT-induced membrane hyperexcitability. Finally, the knockdown of apPDE4s in sensory neurons impaired both short-term and long-term facilitation. Thus, these results suggest that apPDE4s can participate in the regulation of cAMP signaling through specific subcellular localization by means of lipid binding activities.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Aplysia
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • Cells, Cultured
  • Cyclic AMP / metabolism
  • Cyclic Nucleotide Phosphodiesterases, Type 4 / chemistry*
  • Cyclic Nucleotide Phosphodiesterases, Type 4 / genetics
  • Cyclic Nucleotide Phosphodiesterases, Type 4 / metabolism*
  • Cysteine / metabolism
  • Ganglia, Invertebrate / cytology
  • Green Fluorescent Proteins / genetics
  • Humans
  • Immunoprecipitation / methods
  • Membrane Lipids / metabolism
  • Membrane Potentials / genetics*
  • Mutation / genetics
  • Presynaptic Terminals / metabolism
  • Protein Isoforms / chemistry
  • Protein Isoforms / genetics
  • Protein Structure, Tertiary
  • RNA Interference / physiology
  • Sensory Receptor Cells / drug effects
  • Sensory Receptor Cells / physiology*
  • Serotonin / pharmacology
  • Subcellular Fractions / drug effects
  • Subcellular Fractions / metabolism
  • Synaptophysin / metabolism
  • Transfection / methods

Substances

  • Membrane Lipids
  • Protein Isoforms
  • Synaptophysin
  • enhanced green fluorescent protein
  • Green Fluorescent Proteins
  • Serotonin
  • Cyclic AMP
  • Cyclic Nucleotide Phosphodiesterases, Type 4
  • Cysteine