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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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A Kinase Anchor Proteins / genetics
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A Kinase Anchor Proteins / metabolism*
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Acetylcholine / metabolism
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Adenylyl Cyclases / genetics
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Adenylyl Cyclases / metabolism*
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Animals
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Calcineurin / genetics
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Calcineurin / metabolism
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Calcium / metabolism
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Cyclic AMP / metabolism*
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Cyclic AMP-Dependent Protein Kinases / genetics
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Cyclic AMP-Dependent Protein Kinases / metabolism*
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Cyclic Nucleotide Phosphodiesterases, Type 4 / genetics
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Cyclic Nucleotide Phosphodiesterases, Type 4 / metabolism*
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Gene Expression Regulation
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HEK293 Cells
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Humans
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Protein Kinase C / genetics
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Protein Kinase C / metabolism*
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Rats
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Receptor, Muscarinic M3 / genetics
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Receptor, Muscarinic M3 / metabolism*
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Signal Transduction
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Single-Cell Analysis
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Transfection
Substances
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A Kinase Anchor Proteins
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AKAP5 protein, human
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Receptor, Muscarinic M3
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Cyclic AMP
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Cyclic AMP-Dependent Protein Kinases
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Protein Kinase C
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Calcineurin
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Cyclic Nucleotide Phosphodiesterases, Type 4
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Adenylyl Cyclases
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adenylyl cyclase 2
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Acetylcholine
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Calcium