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N-methyl-D-aspartate receptors mediate the phosphorylation and desensitization of muscarinic receptors in cerebellar granule neurons.

Butcher AJ, Torrecilla I, Young KW, Kong KC, Mistry SC, Bottrill AR, Tobin AB - J. Biol. Chem. (2009)

Bottom Line: NMDA receptors themselves are subject to regulation through signaling pathways that are activated by G-protein-coupled receptors (GPCRs).We show that NMDA receptor activation results in the phosphorylation and desensitization of M(3)-muscarinic receptors through a mechanism dependent on NMDA-mediated calcium influx and the activity of calcium-calmodulin-dependent protein kinase II.Our study reveals a complex pattern of regulation where GPCRs (M(3)-muscarinic) and NMDA receptors can feedback on each other in a process that is likely to influence the threshold value of signaling networks involved in synaptic plasticity.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Physiology and Pharmacology, University of Leicesterm, Hodgkin Building, Lancaster Road, Leicester LE1 9HN, United Kingdom.

ABSTRACT
Changes in synaptic strength mediated by ionotropic glutamate N-methyl-D-asparate (NMDA) receptors is generally considered to be the molecular mechanism underlying memory and learning. NMDA receptors themselves are subject to regulation through signaling pathways that are activated by G-protein-coupled receptors (GPCRs). In this study we investigate the ability of NMDA receptors to regulate the signaling of GPCRs by focusing on the G(q/11)-coupled M(3)-muscarinic receptor expressed endogenously in mouse cerebellar granule neurons. We show that NMDA receptor activation results in the phosphorylation and desensitization of M(3)-muscarinic receptors through a mechanism dependent on NMDA-mediated calcium influx and the activity of calcium-calmodulin-dependent protein kinase II. Our study reveals a complex pattern of regulation where GPCRs (M(3)-muscarinic) and NMDA receptors can feedback on each other in a process that is likely to influence the threshold value of signaling networks involved in synaptic plasticity.

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NMDA-mediated phosphorylation of the M3-muscarinic receptor does not mediate receptor internalization. CG neurons were stimulated with agonists (100 μm) for the indicated times. Surface M3-muscarinic receptor expression was then determined using the hydrophilic muscarinic antagonist [3H] n-methyl scopolamine. The data represent the means ± S.D. of three experiments carried out in duplicate.
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Figure 5: NMDA-mediated phosphorylation of the M3-muscarinic receptor does not mediate receptor internalization. CG neurons were stimulated with agonists (100 μm) for the indicated times. Surface M3-muscarinic receptor expression was then determined using the hydrophilic muscarinic antagonist [3H] n-methyl scopolamine. The data represent the means ± S.D. of three experiments carried out in duplicate.

Mentions: Our laboratory and others have shown a clear link between the phosphorylation of M3-muscarinic receptors and receptor internalization (29, 36). Here we tested whether stimulation of M3-muscarinic receptor phosphorylation via NMDA receptors was able to mediate receptor internalization in CG neurons. Despite there being significant levels of receptor phosphorylation at early time points following NMDA stimulation, there was no evidence of a change in the cell surface expression of M3-muscarinic receptors as determined by radioligand binding (Fig. 5). In contrast, stimulation of the muscarinic receptors with the muscarinic agonist methacholine resulted in robust receptor internalization (Fig. 5).


N-methyl-D-aspartate receptors mediate the phosphorylation and desensitization of muscarinic receptors in cerebellar granule neurons.

Butcher AJ, Torrecilla I, Young KW, Kong KC, Mistry SC, Bottrill AR, Tobin AB - J. Biol. Chem. (2009)

NMDA-mediated phosphorylation of the M3-muscarinic receptor does not mediate receptor internalization. CG neurons were stimulated with agonists (100 μm) for the indicated times. Surface M3-muscarinic receptor expression was then determined using the hydrophilic muscarinic antagonist [3H] n-methyl scopolamine. The data represent the means ± S.D. of three experiments carried out in duplicate.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2719353&req=5

Figure 5: NMDA-mediated phosphorylation of the M3-muscarinic receptor does not mediate receptor internalization. CG neurons were stimulated with agonists (100 μm) for the indicated times. Surface M3-muscarinic receptor expression was then determined using the hydrophilic muscarinic antagonist [3H] n-methyl scopolamine. The data represent the means ± S.D. of three experiments carried out in duplicate.
Mentions: Our laboratory and others have shown a clear link between the phosphorylation of M3-muscarinic receptors and receptor internalization (29, 36). Here we tested whether stimulation of M3-muscarinic receptor phosphorylation via NMDA receptors was able to mediate receptor internalization in CG neurons. Despite there being significant levels of receptor phosphorylation at early time points following NMDA stimulation, there was no evidence of a change in the cell surface expression of M3-muscarinic receptors as determined by radioligand binding (Fig. 5). In contrast, stimulation of the muscarinic receptors with the muscarinic agonist methacholine resulted in robust receptor internalization (Fig. 5).

Bottom Line: NMDA receptors themselves are subject to regulation through signaling pathways that are activated by G-protein-coupled receptors (GPCRs).We show that NMDA receptor activation results in the phosphorylation and desensitization of M(3)-muscarinic receptors through a mechanism dependent on NMDA-mediated calcium influx and the activity of calcium-calmodulin-dependent protein kinase II.Our study reveals a complex pattern of regulation where GPCRs (M(3)-muscarinic) and NMDA receptors can feedback on each other in a process that is likely to influence the threshold value of signaling networks involved in synaptic plasticity.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Physiology and Pharmacology, University of Leicesterm, Hodgkin Building, Lancaster Road, Leicester LE1 9HN, United Kingdom.

ABSTRACT
Changes in synaptic strength mediated by ionotropic glutamate N-methyl-D-asparate (NMDA) receptors is generally considered to be the molecular mechanism underlying memory and learning. NMDA receptors themselves are subject to regulation through signaling pathways that are activated by G-protein-coupled receptors (GPCRs). In this study we investigate the ability of NMDA receptors to regulate the signaling of GPCRs by focusing on the G(q/11)-coupled M(3)-muscarinic receptor expressed endogenously in mouse cerebellar granule neurons. We show that NMDA receptor activation results in the phosphorylation and desensitization of M(3)-muscarinic receptors through a mechanism dependent on NMDA-mediated calcium influx and the activity of calcium-calmodulin-dependent protein kinase II. Our study reveals a complex pattern of regulation where GPCRs (M(3)-muscarinic) and NMDA receptors can feedback on each other in a process that is likely to influence the threshold value of signaling networks involved in synaptic plasticity.

Show MeSH