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

Houslay, M. D., Lynch, M. J. and Baillie, G. S. (2007) 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. Biochemical Society Transactions, 35(5), pp. 938-941. (doi: 10.1042/BST0350938)

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Publisher's URL: http://dx.doi.org/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 β-arrestin-sequestered subpopulation of the PDE4D5 isoform specifically regulates the phosphorylation of the β2-AR (β2-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 β-arrestin-sequestered PDE4D5 shapes the spatial cAMP gradient around the membrane-bound β2-AR, regulating its phosphorylation by PKA and its ability to activate ERK (extracellular-signal-regulated kinase) through Gi 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.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Baillie, Professor George and Houslay, Professor Miles
Authors: Houslay, M. D., Lynch, M. J., and Baillie, G. S.
College/School:College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
Journal Name:Biochemical Society Transactions
Publisher:Portland Press Ltd.
ISSN:0300-5127
ISSN (Online):1470-8752
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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
438301Phosphodiesterase-4 isoforms - intracellular targeting, regulation and potential therapeutic targetsMiles HouslayMedical Research Council (MRC)G0600765Institute of Neuroscience and Psychology