title: Phosphodiesterase 4 interacts with the 5-HT4(b) receptor to regulate cAMP signaling.
abstract: Phosphodiesterase (PDE) 3 and PDE4, which degrade cyclic adenosine monophosphate (cAMP), are important regulators of 5-hydroxytryptamine (5-HT) 4 receptor signaling in cardiac tissue. Therefore, we investigated whether they interact with the 5-HT4(b) receptor, and whether A-kinase anchoring proteins (AKAPs), scaffolding proteins that bind to the regulatory subunit of protein kinase A (PKA) and contribute to the spacial-temporal control of cAMP signaling, are involved in the regulation of 5-HT4(b) receptor signaling. By measuring PKA activity in the absence and presence of PDE3 and PDE4 inhibitiors, we found that constitutive signaling of the overexpressed HA-tagged 5-HT4(b) receptor in HEK293 cells is regulated predominantly by PDE4, with a secondary role for PDE3 that is unmasked in the presence of PDE4 inhibition. Overexpressed PDE4D3 and PDE3A1, and to a smaller extent PDE4D5 co-immunoprecipitate constitutively with the 5-HT4(b) receptor. PDE activity measurements in immunoprecipitates of the 5-HT4(b) receptor confirm the association of PDE4D3 with the receptor and provide evidence that the activity of this PDE may be increased upon receptor stimulation with 5-HT. A possible involvement of AKAPs in 5-HT4(b) receptor signaling was uncovered in experiments using the St-Ht31 inhibitor peptide, which disrupts the interaction of AKAPs with PKA. However, St-Ht31 did not influence 5-HT4(b) receptor-stimulated PKA activity, and endogenous AKAP79 and gravin were not found in immunoprecipitates of the 5-HT4(b) receptor. In conclusion, we found that both PDE3A1 and PDE4D3 are integrated into complexes that contain the 5-HT4(b) receptor and may thereby regulate 5-HT4(b) receptor-mediated signaling.
authors.affiliation: Heymans Institute of Pharmacology, Ghent University, De Pintelaan 185, Ghent 9000, Belgium.
authors.forename: S
authors.initials: S
authors.lastname: Weninger
authors.affiliation: Laboratory for Eukaryotic Gene Expression and Signal Transduction, Ghent University, Proeftuinstraat 86, Ghent 9000, Belgium.
authors.forename: K
authors.initials: K
authors.lastname: Van Craenenbroeck
authors.affiliation: Institute of Cardiovascular and Medical Science, University of Glasgow, Office 534, Wolfson-Link Building, Glasgow G12 8QQ, UK.
authors.forename: R T
authors.initials: RT
authors.lastname: Cameron
authors.affiliation: Cardiovascular Medicine Division, VA Salt Lake City Health Care System and University of Utah School of Medicine, Salt Lake City, UT 84148, USA.
authors.forename: F
authors.initials: F
authors.lastname: Vandeput
authors.affiliation: Cardiovascular Medicine Division, VA Salt Lake City Health Care System and University of Utah School of Medicine, Salt Lake City, UT 84148, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Movsesian
authors.affiliation: Institute of Cardiovascular and Medical Science, University of Glasgow, Office 534, Wolfson-Link Building, Glasgow G12 8QQ, UK.
authors.forename: G S
authors.initials: GS
authors.lastname: Baillie
authors.affiliation: Heymans Institute of Pharmacology, Ghent University, De Pintelaan 185, Ghent 9000, Belgium. Electronic address: romain.lefebvre@ugent.be.
authors.forename: R A
authors.initials: RA
authors.lastname: Lefebvre
mesh_terms: D054758:A Kinase Anchor Proteins / Q000235:genetics / Q000378:metabolism; D000242:Cyclic AMP / Q000235:genetics / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3 / Q000235:genetics / Q000378:metabolism; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4 / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D044422:Receptors, Serotonin, 5-HT4 / Q000235:genetics / Q000378:metabolism*; D015290:Second Messenger Systems / Q000502:physiology*
chemical_list: D054758:A Kinase Anchor Proteins; C487775:AKAP5 protein, human; D044422:Receptors, Serotonin, 5-HT4; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; C517287:PDE3A protein, human
keywords: 5-HT(4) receptor signaling; PDE3A1; PDE3A2; PDE3B; PDE4D3; PDE4D5