Rate of Homologous Desensitization and Internalization of the GLP-1 Receptor
The glucagon-like peptide-1 receptor (GLP-1R) is an important target in the treatment of type 2 diabetes mellitus. The aim of this study was to compare the rate of agonist stimulated desensitization and internalization of GLP-1R. To this end, an N-terminally myc-tagged GLP-1R was stably expressed in...
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MDPI AG
2016-12-01
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| Series: | Molecules |
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| Online Access: | http://www.mdpi.com/1420-3049/22/1/22 |
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| author | Ghina Shaaban Mabayoje Oriowo Suleiman Al-Sabah |
| author_facet | Ghina Shaaban Mabayoje Oriowo Suleiman Al-Sabah |
| author_sort | Ghina Shaaban |
| collection | DOAJ |
| description | The glucagon-like peptide-1 receptor (GLP-1R) is an important target in the treatment of type 2 diabetes mellitus. The aim of this study was to compare the rate of agonist stimulated desensitization and internalization of GLP-1R. To this end, an N-terminally myc-tagged GLP-1R was stably expressed in HEK-293 cells. Homologous desensitization was assessed by measuring the cAMP response to agonist stimulation following pre-incubation with agonist for up to 120 min. Receptor internalization was monitored using an indirect ELISA-based method and confocal microscopy. Pre-incubation with GLP-1 resulted in a time-dependent loss of response to a second stimulation. Washing cells following pre-incubation failed to bring cAMP levels back to basal. Taking this into account, two desensitization rates were calculated: “apparent” (t1/2 = 19.27 min) and “net” (t1/2 = 2.99 min). Incubation of cells with GLP-1 also resulted in a time-dependent loss of receptor cell surface expression (t1/2 = 2.05 min). Rapid agonist-stimulated internalization of GLP-1R was confirmed using confocal microscopy. Stimulation of GLP-1R with GLP-1 results in rapid desensitization and internalization of the receptor. Interestingly, the rate of “net” desensitization closely matches the rate of internalization. Our results suggest that agonist-bound GLP-1R continues to generate cAMP after it has been internalized. |
| first_indexed | 2024-12-13T06:12:11Z |
| format | Article |
| id | doaj.art-6363df95815a46a89fcac07896ffed9a |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-12-13T06:12:11Z |
| publishDate | 2016-12-01 |
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| spelling | doaj.art-6363df95815a46a89fcac07896ffed9a2022-12-21T23:57:03ZengMDPI AGMolecules1420-30492016-12-012212210.3390/molecules22010022molecules22010022Rate of Homologous Desensitization and Internalization of the GLP-1 ReceptorGhina Shaaban0Mabayoje Oriowo1Suleiman Al-Sabah2Department of Pharmacology & Toxicology, Faculty of Medicine, Kuwait University, PO Box 24923, 13110 Safat, KuwaitDepartment of Pharmacology & Toxicology, Faculty of Medicine, Kuwait University, PO Box 24923, 13110 Safat, KuwaitDepartment of Pharmacology & Toxicology, Faculty of Medicine, Kuwait University, PO Box 24923, 13110 Safat, KuwaitThe glucagon-like peptide-1 receptor (GLP-1R) is an important target in the treatment of type 2 diabetes mellitus. The aim of this study was to compare the rate of agonist stimulated desensitization and internalization of GLP-1R. To this end, an N-terminally myc-tagged GLP-1R was stably expressed in HEK-293 cells. Homologous desensitization was assessed by measuring the cAMP response to agonist stimulation following pre-incubation with agonist for up to 120 min. Receptor internalization was monitored using an indirect ELISA-based method and confocal microscopy. Pre-incubation with GLP-1 resulted in a time-dependent loss of response to a second stimulation. Washing cells following pre-incubation failed to bring cAMP levels back to basal. Taking this into account, two desensitization rates were calculated: “apparent” (t1/2 = 19.27 min) and “net” (t1/2 = 2.99 min). Incubation of cells with GLP-1 also resulted in a time-dependent loss of receptor cell surface expression (t1/2 = 2.05 min). Rapid agonist-stimulated internalization of GLP-1R was confirmed using confocal microscopy. Stimulation of GLP-1R with GLP-1 results in rapid desensitization and internalization of the receptor. Interestingly, the rate of “net” desensitization closely matches the rate of internalization. Our results suggest that agonist-bound GLP-1R continues to generate cAMP after it has been internalized.http://www.mdpi.com/1420-3049/22/1/22GLP-1receptordesensitizationinternalization |
| spellingShingle | Ghina Shaaban Mabayoje Oriowo Suleiman Al-Sabah Rate of Homologous Desensitization and Internalization of the GLP-1 Receptor Molecules GLP-1 receptor desensitization internalization |
| title | Rate of Homologous Desensitization and Internalization of the GLP-1 Receptor |
| title_full | Rate of Homologous Desensitization and Internalization of the GLP-1 Receptor |
| title_fullStr | Rate of Homologous Desensitization and Internalization of the GLP-1 Receptor |
| title_full_unstemmed | Rate of Homologous Desensitization and Internalization of the GLP-1 Receptor |
| title_short | Rate of Homologous Desensitization and Internalization of the GLP-1 Receptor |
| title_sort | rate of homologous desensitization and internalization of the glp 1 receptor |
| topic | GLP-1 receptor desensitization internalization |
| url | http://www.mdpi.com/1420-3049/22/1/22 |
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