Phosphodiesterase 4 interacts with the 5-HT4(b) receptor to regulate cAMP signaling

• Published in: Cellular signalling 2014-11, Vol.26 (11), p.2573-2582
• Main Authors: Weninger, S., Van Craenenbroeck, K., Cameron, R.T., Vandeput, F., Movsesian, M.A., Baillie, G.S., Lefebvre, R.A.
• Format: Article
• Language: English
• Subjects: 5-HT4 receptor signaling; A Kinase Anchor Proteins - genetics; A Kinase Anchor Proteins - metabolism; Cyclic AMP - genetics; Cyclic AMP - metabolism; Cyclic AMP-Dependent Protein Kinases - genetics; Cyclic AMP-Dependent Protein Kinases - metabolism; Cyclic Nucleotide Phosphodiesterases, Type 3 - genetics; Cyclic Nucleotide Phosphodiesterases, Type 3 - metabolism; Cyclic Nucleotide Phosphodiesterases, Type 4 - genetics; Cyclic Nucleotide Phosphodiesterases, Type 4 - metabolism; HEK293 Cells; Humans; PDE3A1; PDE3A2; PDE3B; PDE4D3; PDE4D5; Receptors, Serotonin, 5-HT4 - genetics; Receptors, Serotonin, 5-HT4 - metabolism; Second Messenger Systems - physiology
• ISSN: 0898-6568; 1873-3913
• DOI: 10.1016/j.cellsig.2014.07.027

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. •5-HT4(b) receptor signaling in HEK293 cells is controlled predominantly by PDE4.•PDE4D3 and PDE4D5 splice variants co-immunoprecipitate with the 5-HT4(b) receptor.•PDE3A1 but not PDE3B were found in association with the 5-HT4(b) receptor.•No evidence found for an involvement of AKAPs 79/250 in 5-HT4(b) receptor signaling