A novel role for a Drosophila homologue of cGMP-specific phosphodiesterase in the active transport of cGMP

Day, J.P., Houslay, M.D. and Davies, S.-A. (2006) A novel role for a Drosophila homologue of cGMP-specific phosphodiesterase in the active transport of cGMP. Biochemical Journal, 393(2), pp. 481-488.

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Abstract

cGMP was first discovered in urine, demonstrating that kidney cells extrude this cyclic nucleotide. Drosophila Malpighian tubules provide a model renal system in which a homologue of mammalian PDE (phosphodiesterase) 6 is expressed. In humans, this cG-PDE (cGMP-specific PDE) is specifically expressed in the retinal system, where it controls visual signal transduction. In order to gain insight into the functional role of DmPDE6 (Drosophila PDE6-like enzyme) in epithelial function, we generated transgenic animals with targeted expression of DmPDE6 to tubule Type I (principal) cells. This revealed localization of DmPDE6 primarily at the apical membranes. As expected, overexpression of DmPDE6 resulted in elevated cG-PDE activity and decreased tubule cGMP content. However, such targeted overexpression of DmPDE6 creates a novel phenotype that manifests itself in inhibition of the active transport and efflux of cGMP by tubules. This effect is specific to DmPDE6 action, as no effect on cGMP transport is observed in tubules from a bovine PDE5 transgenic line which display reduced rates of fluid secretion, an effect not seen in DmPDE6 transgenic animals. Specific ablation of DmPDE6 in tubule principal cells, via expression of a targeted DmPDE6 RNAi (RNA interference) transgene, conferred increased active transport of cGMP, confirming a direct role for DmPDE6 in regulating cGMP transport in tubule principal cells. Pharmacological inhibition of DmPDE6 in wild-type tubules using the cG-PDE inhibitor, zaprinast, similarly results in stimulated cGMP transport. We provide the first demonstration of a novel role for a cG-PDE in modulating cGMP transport and efflux.

Item Type:Articles
Keywords:cGMP, Drosophila, phosphodiesterase 6 (PDE6), renal epithelium, RNA interference (RNAi)
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Houslay, Professor Miles
Authors: Day, J.P., Houslay, M.D., and Davies, S.-A.
Subjects:Q Science > QR Microbiology
College/School:College of Medical Veterinary and Life Sciences > Institute of Neuroscience and Psychology
Journal Name:Biochemical Journal
Publisher:Portland Press Ltd.
ISSN:0264-6021
ISSN (Online):1470-8728

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
208361PDE4 cAMP phosphodiesterses: intracellular targeting, SH3 domain interaction and phosphorylation by stress kinasesMiles HouslayMedical Research Council (MRC)G8604010Institute of Neuroscience and Psychology
294081PDE4 Cyclic AMP phosphodiesterasesMiles HouslayMedical Research Council (MRC)G8604010Institute of Neuroscience and Psychology
30692Molecular interaction between receptor signal transduction systems involving guanine nucleotide regulatory proteinsMiles HouslayMedical Research Council (MRC)G8604010Institute of Neuroscience and Psychology
343641PDE4 cAMP phosphodiesterases - intracellular targeting, SH3 Domain Interaction & phosphorylation by stress kinasesMiles HouslayMedical Research Council (MRC)G8604010Institute of Neuroscience and Psychology
97371Programme Grant (PG 8604010) Supplementation (Equipment). Molecular interaction between receptor transduction systems involving guanine nuclMiles HouslayMedical Research Council (MRC)G8604010Institute of Neuroscience and Psychology