Negative cooperativity across 1-adrenoceptor homodimers provides insights into the nature of the secondary low-affinity CGP 12177 1-adrenoceptor binding conformation
At the β1-adrenoceptor, CGP 12177 potently antagonizes agonist responses at the primary high-affinity catecholamine conformation while also exerting agonist effects of its own through a secondary low-affinity conformation. A recent mutagenesis study identified transmembrane region (TM)4 of the β1-ad...
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Federation of American Society of Experimental Biology
2015
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| Online Access: | https://eprints.nottingham.ac.uk/35142/ |
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| author | Gherbi, Karolina May, Lauren T. Baker, Jillian G. Briddon, Stephen J. Hill, Stephen J. |
| author_facet | Gherbi, Karolina May, Lauren T. Baker, Jillian G. Briddon, Stephen J. Hill, Stephen J. |
| author_sort | Gherbi, Karolina |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | At the β1-adrenoceptor, CGP 12177 potently antagonizes agonist responses at the primary high-affinity catecholamine conformation while also exerting agonist effects of its own through a secondary low-affinity conformation. A recent mutagenesis study identified transmembrane region (TM)4 of the β1-adrenoceptor as key for this low-affinity conformation. Others suggested that TM4 has a role in β1-adrenoceptor oligomerization. Here, assessment of the dissociation rate of a fluorescent analog of CGP 12177 [bordifluoropyrromethane-tetramethylrhodamine-(±)CGP 12177 (BODIPY-TMR-CGP)] at the human β1-adrenoceptor expressed in Chinese hamster ovary cells revealed negative cooperative interactions between 2 distinct β1-adrenoceptor conformations. The dissociation rate of 3 nM BODIPY-TMR-CGP was 0.09 ± 0.01 min−1 in the absence of competitor ligands, and this was enhanced 2.2- and 2.1-fold in the presence of 1 µM CGP 12177 and 1 µM propranolol, respectively. These effects on the BODIPY-TMR-CGP dissociation rate were markedly enhanced in β1-adrenoceptor homodimers constrained by bimolecular fluorescence complementation (9.8- and 9.9-fold for 1 µM CGP 12177 and 1 µM propranolol, respectively) and abolished in β1-adrenoceptors containing TM4 mutations vital for the second conformation pharmacology. This study suggests that negative cooperativity across a β1-adrenoceptor homodimer may be responsible for generating the low-affinity pharmacology of the secondary β1-adrenoceptor conformation |
| first_indexed | 2025-11-14T19:25:18Z |
| format | Article |
| id | nottingham-35142 |
| institution | University of Nottingham Malaysia Campus |
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| last_indexed | 2025-11-14T19:25:18Z |
| publishDate | 2015 |
| publisher | Federation of American Society of Experimental Biology |
| recordtype | eprints |
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| spelling | nottingham-351422020-05-04T20:08:04Z https://eprints.nottingham.ac.uk/35142/ Negative cooperativity across 1-adrenoceptor homodimers provides insights into the nature of the secondary low-affinity CGP 12177 1-adrenoceptor binding conformation Gherbi, Karolina May, Lauren T. Baker, Jillian G. Briddon, Stephen J. Hill, Stephen J. At the β1-adrenoceptor, CGP 12177 potently antagonizes agonist responses at the primary high-affinity catecholamine conformation while also exerting agonist effects of its own through a secondary low-affinity conformation. A recent mutagenesis study identified transmembrane region (TM)4 of the β1-adrenoceptor as key for this low-affinity conformation. Others suggested that TM4 has a role in β1-adrenoceptor oligomerization. Here, assessment of the dissociation rate of a fluorescent analog of CGP 12177 [bordifluoropyrromethane-tetramethylrhodamine-(±)CGP 12177 (BODIPY-TMR-CGP)] at the human β1-adrenoceptor expressed in Chinese hamster ovary cells revealed negative cooperative interactions between 2 distinct β1-adrenoceptor conformations. The dissociation rate of 3 nM BODIPY-TMR-CGP was 0.09 ± 0.01 min−1 in the absence of competitor ligands, and this was enhanced 2.2- and 2.1-fold in the presence of 1 µM CGP 12177 and 1 µM propranolol, respectively. These effects on the BODIPY-TMR-CGP dissociation rate were markedly enhanced in β1-adrenoceptor homodimers constrained by bimolecular fluorescence complementation (9.8- and 9.9-fold for 1 µM CGP 12177 and 1 µM propranolol, respectively) and abolished in β1-adrenoceptors containing TM4 mutations vital for the second conformation pharmacology. This study suggests that negative cooperativity across a β1-adrenoceptor homodimer may be responsible for generating the low-affinity pharmacology of the secondary β1-adrenoceptor conformation Federation of American Society of Experimental Biology 2015-07 Article PeerReviewed Gherbi, Karolina, May, Lauren T., Baker, Jillian G., Briddon, Stephen J. and Hill, Stephen J. (2015) Negative cooperativity across 1-adrenoceptor homodimers provides insights into the nature of the secondary low-affinity CGP 12177 1-adrenoceptor binding conformation. FASEB Journal, 29 (7). pp. 2859-2871. ISSN 1530-6860 dissociation; receptor dimerization; GPCR; allosterism http://www.fasebj.org/content/29/7/2859 doi:10.1096/fj.14-265199 doi:10.1096/fj.14-265199 |
| spellingShingle | dissociation; receptor dimerization; GPCR; allosterism Gherbi, Karolina May, Lauren T. Baker, Jillian G. Briddon, Stephen J. Hill, Stephen J. Negative cooperativity across 1-adrenoceptor homodimers provides insights into the nature of the secondary low-affinity CGP 12177 1-adrenoceptor binding conformation |
| title | Negative cooperativity across 1-adrenoceptor homodimers provides insights into the nature of the secondary low-affinity CGP 12177 1-adrenoceptor binding conformation |
| title_full | Negative cooperativity across 1-adrenoceptor homodimers provides insights into the nature of the secondary low-affinity CGP 12177 1-adrenoceptor binding conformation |
| title_fullStr | Negative cooperativity across 1-adrenoceptor homodimers provides insights into the nature of the secondary low-affinity CGP 12177 1-adrenoceptor binding conformation |
| title_full_unstemmed | Negative cooperativity across 1-adrenoceptor homodimers provides insights into the nature of the secondary low-affinity CGP 12177 1-adrenoceptor binding conformation |
| title_short | Negative cooperativity across 1-adrenoceptor homodimers provides insights into the nature of the secondary low-affinity CGP 12177 1-adrenoceptor binding conformation |
| title_sort | negative cooperativity across 1-adrenoceptor homodimers provides insights into the nature of the secondary low-affinity cgp 12177 1-adrenoceptor binding conformation |
| topic | dissociation; receptor dimerization; GPCR; allosterism |
| url | https://eprints.nottingham.ac.uk/35142/ https://eprints.nottingham.ac.uk/35142/ https://eprints.nottingham.ac.uk/35142/ |