Phosphodiesterase 4 interacts with the 5-HT4(b) receptor to regulate cAMP signaling |
| |
| Affiliation: | 1. Heymans Institute of Pharmacology, Ghent University, De Pintelaan 185, Ghent 9000, Belgium;2. Laboratory for Eukaryotic Gene Expression and Signal Transduction, Ghent University, Proeftuinstraat 86, Ghent 9000, Belgium;3. Institute of Cardiovascular and Medical Science, University of Glasgow, Office 534, Wolfson-Link Building, Glasgow G12 8QQ, UK;4. Cardiovascular Medicine Division, VA Salt Lake City Health Care System and University of Utah School of Medicine, Salt Lake City, UT 84148, USA;1. Dept. of Pharmacology and Pharmacotherapy, University of Szeged, Szeged, Hungary;2. Gedeon Richter Plc., Budapest, Hungary;3. 2nd Dept. of Medicine and Cardiology Centre, University of Szeged, Szeged, Hungary;4. Department of Electrical Engineering and Cybernetics, Kecskemét College, Kecskemét, Hungary;5. Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary;6. Bolyai Institute, University of Szeged, Szeged, Hungary;7. MTA-SZTE Research Group of Cardiovascular Pharmacology, Hungarian Academy of Sciences, Szeged, Hungary |
| |
| 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. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
