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Structure and Conformational Changes in the C-terminal Domain of the β2-Adrenoceptor.
- Source :
-
Journal of Biological Chemistry . 5/4/2007, Vol. 282 Issue 18, p13895-13905. 11p. 1 Diagram, 5 Graphs. - Publication Year :
- 2007
-
Abstract
- The C terminus of the β2-adrenoceptor (AR) interacts with G protein-coupled receptor kinases and arrestins in an agonist-dependent manner, suggesting that conformational changes induced by ligands in the transmembrane domains are transmitted to the C terminus. We used fluorescence resonance energy transfer (FRET) to examine ligand-induced structural changes in the distance between two positions on the β2-AR C terminus and cysteine 265 (Cys-265) at the cytoplasmic end of transmembrane domain 6. The donor fluorophore FlAsH (Fluorescein Arsenical Helix binder) was attached to a CCPGCC motif introduced at position 351-356 in the proximal C terminus or at the distal C terminus. An acceptor fluorophore, Alexa Fluor 568, was attached to Cys-265. FRET analyses revealed that the average distances between Cys-265 and the proximal and distal FlAsH sites were 57 and 62 Å, respectively. These relatively large distances suggest that the C terminus is in an extended, relatively unstructured conformation. Nevertheless, we observed ligand-specific changes in FRET. All ligands induced an increase in FRET between the proximal C-terminal FlAsH site and Cys-265. Ligands that have been shown to induce arrestin-dependent ERK activation, including the catecholamine agonists and the inverse agonist ICI118551, led to a decrease in FRET between the distal FlAsH site and Cys-265, whereas other ligands had no effect or induced a small increase in FRET. Taken together the results provide new insight into the structure of the C terminus of the β2-AR as well as ligand-induced conformational changes that may be relevant to arrestin-dependent regulation and signaling. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00219258
- Volume :
- 282
- Issue :
- 18
- Database :
- Academic Search Index
- Journal :
- Journal of Biological Chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 25374180
- Full Text :
- https://doi.org/10.1074/jbc.M611904200