cAMP-specific phosphodiesterase-4D5 (PDE4D5) provides a paradigm for understanding the unique non-redundant roles that PDE4 isoforms play in shaping compartmentalized cAMP cell signalling

Biochem Soc Trans. 2007 Nov;35(Pt 5):938-41. doi: 10.1042/BST0350938.

Abstract

The PDE4 (phosphodiesterase-4) enzyme family consists of a distinct array of N-terminal splice variant isoforms arising from four subfamily genes (4A, 4B, 4C and 4D). These all hydrolyse specifically the intracellular second messenger cAMP. Although identical in catalytic function, each isoform appears to serve a non-superfluous regulatory role. For example, a beta-arrestin-sequestered subpopulation of the PDE4D5 isoform specifically regulates the phosphorylation of the beta(2)-AR (beta(2)-adrenergic receptor) by PKA (protein kinase A; also called cAMP-dependent protein kinase). This was elucidated by the use of novel technologies, including dominant-negative approaches, siRNA (small interfering RNA) knockdown and spot-immobilized peptide array analyses. Functional phenotypes uncovered using these methodologies have shown that beta-arrestin-sequestered PDE4D5 shapes the spatial cAMP gradient around the membrane-bound beta(2)-AR, regulating its phosphorylation by PKA and its ability to activate ERK (extracellular-signal-regulated kinase) through G(i) in cardiomyocytes and HEK-293 (human embryonic kidney)-B2 cells. This approach has provided the very first identification of a non-redundant and specific role for a PDE isoform. The fact that phenotypes can be uncovered by displacing PDE4 isoforms from specific anchor sites using dominant-negative constructs and cell-permeable peptides points to novel means for developing therapeutics aimed at disrupting specifically sequestered PDE isoforms and even specifically sequestered subpopulations of individual isoforms.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Arrestins / chemistry
  • Arrestins / metabolism
  • Cell Compartmentation
  • Cell Line
  • Cyclic AMP / metabolism*
  • Cyclic Nucleotide Phosphodiesterases, Type 3
  • Cyclic Nucleotide Phosphodiesterases, Type 4
  • Humans
  • Phosphoric Diester Hydrolases / metabolism*
  • Phosphorylation
  • Receptors, Adrenergic, beta-2 / metabolism
  • Signal Transduction*
  • beta-Arrestins

Substances

  • Arrestins
  • Receptors, Adrenergic, beta-2
  • beta-Arrestins
  • Cyclic AMP
  • Phosphoric Diester Hydrolases
  • Cyclic Nucleotide Phosphodiesterases, Type 3
  • Cyclic Nucleotide Phosphodiesterases, Type 4
  • PDE4D protein, human