Subtype differences in pre-coupling of muscarinic acetylcholine receptors.
Based on the kinetics of interaction between a receptor and G-protein, a myriad of possibilities may result. Two extreme cases are represented by: 1/Collision coupling, where an agonist binds to the free receptor and then the agonist-receptor complex "collides" with the free G-protein. 2/P...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Public Library of Science (PLoS)
2011-01-01
|
| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC3218020?pdf=render |
| _version_ | 1828387352622399488 |
|---|---|
| author | Jan Jakubík Helena Janíčková Alena Randáková Esam E El-Fakahany Vladimír Doležal |
| author_facet | Jan Jakubík Helena Janíčková Alena Randáková Esam E El-Fakahany Vladimír Doležal |
| author_sort | Jan Jakubík |
| collection | DOAJ |
| description | Based on the kinetics of interaction between a receptor and G-protein, a myriad of possibilities may result. Two extreme cases are represented by: 1/Collision coupling, where an agonist binds to the free receptor and then the agonist-receptor complex "collides" with the free G-protein. 2/Pre-coupling, where stable receptor/G-protein complexes exist in the absence of agonist. Pre-coupling plays an important role in the kinetics of signal transduction. Odd-numbered muscarinic acetylcholine receptors preferentially couple to G(q/11), while even-numbered receptors prefer coupling to G(i/o). We analyzed the coupling status of the various subtypes of muscarinic receptors with preferential and non-preferential G-proteins. The magnitude of receptor-G-protein coupling was determined by the proportion of receptors existing in the agonist high-affinity binding conformation. Antibodies directed against the C-terminus of the α-subunits of the individual G-proteins were used to interfere with receptor-G-protein coupling. Effects of mutations and expression level on receptor-G-protein coupling were also investigated. Tested agonists displayed biphasic competition curves with the antagonist [(3)H]-N-methylscopolamine. Antibodies directed against the C-terminus of the α-subunits of the preferential G-protein decreased the proportion of high-affinity sites, and mutations at the receptor-G-protein interface abolished agonist high-affinity binding. In contrast, mutations that prevent receptor activation had no effect. Expression level of preferential G-proteins had no effect on pre-coupling to non-preferential G-proteins. Our data show that all subtypes of muscarinic receptors pre-couple with their preferential classes of G-proteins, but only M(1) and M(3) receptors also pre-couple with non-preferential G(i/o) G-proteins. Pre-coupling is not dependent on agonist efficacy nor on receptor activation. The ultimate mode of coupling is therefore dictated by a combination of the receptor subtype and the class of G-protein. |
| first_indexed | 2024-12-10T05:53:19Z |
| format | Article |
| id | doaj.art-58d46b86f0364896b73fb79d7669db8b |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-10T05:53:19Z |
| publishDate | 2011-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-58d46b86f0364896b73fb79d7669db8b2022-12-22T02:00:00ZengPublic Library of Science (PLoS)PLoS ONE1932-62032011-01-01611e2773210.1371/journal.pone.0027732Subtype differences in pre-coupling of muscarinic acetylcholine receptors.Jan JakubíkHelena JaníčkováAlena RandákováEsam E El-FakahanyVladimír DoležalBased on the kinetics of interaction between a receptor and G-protein, a myriad of possibilities may result. Two extreme cases are represented by: 1/Collision coupling, where an agonist binds to the free receptor and then the agonist-receptor complex "collides" with the free G-protein. 2/Pre-coupling, where stable receptor/G-protein complexes exist in the absence of agonist. Pre-coupling plays an important role in the kinetics of signal transduction. Odd-numbered muscarinic acetylcholine receptors preferentially couple to G(q/11), while even-numbered receptors prefer coupling to G(i/o). We analyzed the coupling status of the various subtypes of muscarinic receptors with preferential and non-preferential G-proteins. The magnitude of receptor-G-protein coupling was determined by the proportion of receptors existing in the agonist high-affinity binding conformation. Antibodies directed against the C-terminus of the α-subunits of the individual G-proteins were used to interfere with receptor-G-protein coupling. Effects of mutations and expression level on receptor-G-protein coupling were also investigated. Tested agonists displayed biphasic competition curves with the antagonist [(3)H]-N-methylscopolamine. Antibodies directed against the C-terminus of the α-subunits of the preferential G-protein decreased the proportion of high-affinity sites, and mutations at the receptor-G-protein interface abolished agonist high-affinity binding. In contrast, mutations that prevent receptor activation had no effect. Expression level of preferential G-proteins had no effect on pre-coupling to non-preferential G-proteins. Our data show that all subtypes of muscarinic receptors pre-couple with their preferential classes of G-proteins, but only M(1) and M(3) receptors also pre-couple with non-preferential G(i/o) G-proteins. Pre-coupling is not dependent on agonist efficacy nor on receptor activation. The ultimate mode of coupling is therefore dictated by a combination of the receptor subtype and the class of G-protein.http://europepmc.org/articles/PMC3218020?pdf=render |
| spellingShingle | Jan Jakubík Helena Janíčková Alena Randáková Esam E El-Fakahany Vladimír Doležal Subtype differences in pre-coupling of muscarinic acetylcholine receptors. PLoS ONE |
| title | Subtype differences in pre-coupling of muscarinic acetylcholine receptors. |
| title_full | Subtype differences in pre-coupling of muscarinic acetylcholine receptors. |
| title_fullStr | Subtype differences in pre-coupling of muscarinic acetylcholine receptors. |
| title_full_unstemmed | Subtype differences in pre-coupling of muscarinic acetylcholine receptors. |
| title_short | Subtype differences in pre-coupling of muscarinic acetylcholine receptors. |
| title_sort | subtype differences in pre coupling of muscarinic acetylcholine receptors |
| url | http://europepmc.org/articles/PMC3218020?pdf=render |
| work_keys_str_mv | AT janjakubik subtypedifferencesinprecouplingofmuscarinicacetylcholinereceptors AT helenajanickova subtypedifferencesinprecouplingofmuscarinicacetylcholinereceptors AT alenarandakova subtypedifferencesinprecouplingofmuscarinicacetylcholinereceptors AT esameelfakahany subtypedifferencesinprecouplingofmuscarinicacetylcholinereceptors AT vladimirdolezal subtypedifferencesinprecouplingofmuscarinicacetylcholinereceptors |