Abstract
The β2 adrenoreceptor (β2AR) is a prototypical G protein-coupled receptor (GPCR) activated by catecholamines. Agonist activation of GPCRs leads to sequential interactions with heterotrimeric G proteins, which activate cellular signaling cascades, and with GPCR kinases and arrestins, which attenuate GPCR-mediated signaling. We used fluorescence spectroscopy to monitor catecholamine-induced conformational changes in purified β 2AR. Here we show that upon catecholamine binding, β 2ARs undergo transitions to two kinetically distinguishable conformational states. Using a panel of chemically related catechol derivatives, we identified the specific chemical groups on the agonist responsible for the rapid and slow conformational changes in the receptor. The conformational changes observed in our biophysical assay were correlated with biologic responses in cellular assays. Dopamine, which induces only a rapid conformational change, is efficient at activating Gs but not receptor internalization. In contrast, norepinephrine and epinephrine, which induce both rapid and slow conformational changes, are efficient at activating Gs and receptor internalization. These results support a mechanistic model for GPCR activation where contacts between the receptor and structural determinants of the agonist stabilize a succession of conformational states with distinct cellular functions.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 686-691 |
| Number of pages | 6 |
| Journal | Journal of Biological Chemistry |
| Volume | 279 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 2 2004 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Biochemistry
Cite this
Sequential binding of agonists to the β2 adrenoceptor. Kinetic evidence for intermediate conformational states. / Swaminath, Gayathri; Xiang, Yang Kevin; Lee, Tae Weon; Steenhuis, Jacqueline; Parnot, Charles; Kobilka, Brian K.
In: Journal of Biological Chemistry, Vol. 279, No. 1, 02.01.2004, p. 686-691.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Sequential binding of agonists to the β2 adrenoceptor. Kinetic evidence for intermediate conformational states
AU - Swaminath, Gayathri
AU - Xiang, Yang Kevin
AU - Lee, Tae Weon
AU - Steenhuis, Jacqueline
AU - Parnot, Charles
AU - Kobilka, Brian K.
PY - 2004/1/2
Y1 - 2004/1/2
N2 - The β2 adrenoreceptor (β2AR) is a prototypical G protein-coupled receptor (GPCR) activated by catecholamines. Agonist activation of GPCRs leads to sequential interactions with heterotrimeric G proteins, which activate cellular signaling cascades, and with GPCR kinases and arrestins, which attenuate GPCR-mediated signaling. We used fluorescence spectroscopy to monitor catecholamine-induced conformational changes in purified β 2AR. Here we show that upon catecholamine binding, β 2ARs undergo transitions to two kinetically distinguishable conformational states. Using a panel of chemically related catechol derivatives, we identified the specific chemical groups on the agonist responsible for the rapid and slow conformational changes in the receptor. The conformational changes observed in our biophysical assay were correlated with biologic responses in cellular assays. Dopamine, which induces only a rapid conformational change, is efficient at activating Gs but not receptor internalization. In contrast, norepinephrine and epinephrine, which induce both rapid and slow conformational changes, are efficient at activating Gs and receptor internalization. These results support a mechanistic model for GPCR activation where contacts between the receptor and structural determinants of the agonist stabilize a succession of conformational states with distinct cellular functions.
AB - The β2 adrenoreceptor (β2AR) is a prototypical G protein-coupled receptor (GPCR) activated by catecholamines. Agonist activation of GPCRs leads to sequential interactions with heterotrimeric G proteins, which activate cellular signaling cascades, and with GPCR kinases and arrestins, which attenuate GPCR-mediated signaling. We used fluorescence spectroscopy to monitor catecholamine-induced conformational changes in purified β 2AR. Here we show that upon catecholamine binding, β 2ARs undergo transitions to two kinetically distinguishable conformational states. Using a panel of chemically related catechol derivatives, we identified the specific chemical groups on the agonist responsible for the rapid and slow conformational changes in the receptor. The conformational changes observed in our biophysical assay were correlated with biologic responses in cellular assays. Dopamine, which induces only a rapid conformational change, is efficient at activating Gs but not receptor internalization. In contrast, norepinephrine and epinephrine, which induce both rapid and slow conformational changes, are efficient at activating Gs and receptor internalization. These results support a mechanistic model for GPCR activation where contacts between the receptor and structural determinants of the agonist stabilize a succession of conformational states with distinct cellular functions.
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UR - http://www.scopus.com/inward/citedby.url?scp=0345791508&partnerID=8YFLogxK
U2 - 10.1074/jbc.M310888200
DO - 10.1074/jbc.M310888200
M3 - Article
C2 - 14559905
AN - SCOPUS:0345791508
VL - 279
SP - 686
EP - 691
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 1
ER -