AKAP79, PKC, PKA and PDE4 participate in a Gq-linked muscarinic receptor and adenylate cyclase 2 cAMP signalling complex

Abstract

AC2 (adenylate cyclase 2) is stimulated by activation of Gq-coupled muscarinic receptors through PKC (protein kinase C) to generate localized cAMP in HEK (human embryonic kidney)-293 cells. In the present study, we utilized a sensitive live-cell imaging technique to unravel the proteins that play essential roles in a Gq-coupled muscarinic receptor-mediated cAMP signalling complex. We reveal that, upon agonist binding to the Gq-coupled muscarinic receptor, AKAP79 (A-kinase-anchoring protein 79) recruits PKC to activate AC2 to produce cAMP. The cAMP formed is degraded by PDE4 (phosphodiesterase 4) activated by an AKAP-anchored PKA (protein kinase A). Calcineurin, a phosphatase bound to AKAP79, is not involved in this regulation. Overall, a transient cAMP increase is generated from AC2 by Gq-coupled muscarinic receptor activation, subject to sophisticated regulation through AKAP79, PKC, PDE4 and PKA, which significantly enhances acetylcholine-mediated signalling.

International Union of Basic and Clinical Pharmacology. CI. Structures and Small Molecule Modulators of Mammalian Adenylyl Cyclases

“…PKC increases activity of certain ACs (ACs 1, 2, 3, 5, 7) but inhibits the activity of others (AC6) (Sunahara et al, 1996;Lai et al, 1997). AKAP5 orchestrates muscarinic receptor activation of cAMP production by recruitment of PKC to a complex containing the PKC-stimulated AC2 (Shen and Cooper, 2013). PDE4 and PKA are also key elements in the complex.…”

“…Several diverse members of the AKAP family interact with ACs in an isoform-specific manner and regulate cAMP signaling (Bauman et al, 2006). To date, the specific AKAP-AC interactions that have been defined are AKAP9/Yotiao with ACs 1, 2, 3, and 9 (Piggott et al, 2008), mAKAP with ACs 2 and 5 (Kapiloff et al, 2009) and AKAP79/150 with ACs 2, 3, 5, 6, 8, and 9 (Efendiev et al, 2010;Delint-Ramirez et al, 2011;Shen and Cooper, 2013).…”

History of the G Protein–Coupled Receptor (GPCR) Assays From Traditional to a State-of-the-Art Biosensor Assay

“…Among the 5 muscarinic acetylcholine receptors (M1 -M5), M1, M3, and M5 acetylcholine receptors couple with the Gq protein, whereas M2 and M4 acetylcholine receptors coupled with the Gi/o protein (25,26). In human embryonic kidney 293 (HEK293) cells, M3 is endogenously expressed at a low level (25,26). We therefore stimulated HEK293 cells with the vehicle or acetylcholine (10 mM).…”

Tricyclic Antidepressant Amitriptyline-induced Glial Cell Line-derived Neurotrophic Factor Production Involves Pertussis Toxin-sensitive Gαi/o Activation in Astroglial Cells

“…To show typical different ⌬Z values caused by each ligand to specific types of GPCRs, HEK293 cells expressing -opioid receptors, coupled to G i/o , and C6 cells endogenously expressing ␤-adrenergic receptors, coupled to G s , were used (14,35). In addition, HEK293 cells, which endogenously express the muscarinic (M 3 ) acetylcholine receptor, were used to show the activation of G q -coupled receptors (36,37). In Fig.…”