Helix-1 of the cAMP-specific phosphodiesterase PDE4A1 regulates its phospholipase-D-dependent redistribution in response to release of Ca2+

J Cell Sci. 2006 Sep 15;119(Pt 18):3799-810. doi: 10.1242/jcs.03106. Epub 2006 Aug 29.

Abstract

The unique N-terminal regions of PDE4 cAMP-specific phosphodiesterases confer interaction with distinct signalling and scaffolding proteins. The PDE4A1 isoform is unique in being entirely membrane associated. Its N-terminal region is formed from two helices separated by a mobile hinge, where helix-2 contains a TAPAS1 domain that inserts into the lipid bilayer in a Ca2+-triggered fashion. Here we show that helix-1 is important for intracellular targeting of PDE4A1 in living cells, facilitating membrane association, targeting to the trans-Golgi stack and conferring Ca2+-stimulated intracellular redistribution in a manner that is dependent on the phospholipase-D-mediated generation of phosphatidic acid. The LxDFF motif within helix-1 is pivotal to this, where Leu4-Phe6-Phe7 forms a compact hydrophobic pocket on one side of helix-1 whereas Asp5, located on the opposite face of helix-1, provides the Ca2+-regulation site. Mutation of Asp5 to Ala or the release of Ca2+ from intracellular stores de-restricts trans-Golgi localisation of PDE4A1 allowing it to redistribute in cells in a phosphatidic-acid-dependent manner. This study provides the first evidence for Ca2+-triggered relocalisation of a cAMP phosphodiesterase and indicates a potential means for allowing cross-talk between the cAMP, phospholipase D and Ca2+-signalling pathways.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3',5'-Cyclic-AMP Phosphodiesterases / chemistry*
  • 3',5'-Cyclic-AMP Phosphodiesterases / metabolism*
  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • COS Cells
  • Calcium / metabolism*
  • Calcium Signaling / drug effects
  • Cell Survival / drug effects
  • Chlorocebus aethiops
  • Cyclic Nucleotide Phosphodiesterases, Type 4
  • Models, Molecular
  • Molecular Sequence Data
  • Phosphatidic Acids / biosynthesis
  • Phospholipase D / metabolism*
  • Protein Structure, Secondary
  • Protein Transport / drug effects
  • Recombinant Fusion Proteins / metabolism
  • Structure-Activity Relationship
  • Thapsigargin / pharmacology
  • trans-Golgi Network / drug effects

Substances

  • Phosphatidic Acids
  • Recombinant Fusion Proteins
  • Thapsigargin
  • 3',5'-Cyclic-AMP Phosphodiesterases
  • Cyclic Nucleotide Phosphodiesterases, Type 4
  • Phospholipase D
  • Calcium