Conformational complexity of G-protein-coupled receptors

Kobilka, Brian K.; Deupí, Xavier

doi:10.1016/j.tips.2007.06.003

Cited by 644 publications

(612 citation statements)

References 38 publications

Supporting

Mentioning

588

Contrasting

Unclassified

Order By: Relevance

“…Previous experimental work has indicated that GPCRs adopt multiple functionally relevant conformations within their active and inactive states (7,8). We used microsecondtimescale MD simulations to characterize the inactive ␤ 2 AR conformational ensemble, focusing on the biochemically defined ionic lock that proved to be unexpectedly broken in the recent ␤ 2 AR and ␤ 1 AR crystal structures.…”

Section: Concluding Remarks)mentioning

confidence: 99%

“…A conformational change from an inactive state to an active state enables the receptor to transmit a signal from the extracellular ligand-binding site to an intracellular G protein, thereby initiating diverse intracellular signaling processes. Several studies have indicated that the active and inactive states of ␤ 2 AR each comprise multiple receptor conformations with different implications for signaling (7,8). In the present work, we used molecular dynamics (MD) simulations to characterize functionally important aspects of the inactive conformational ensemble.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Identification of two distinct inactive conformations of the β ₂ -adrenergic receptor reconciles structural and biochemical observations

Dror

Arlow

Borhani

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

291

236

View full text Add to dashboard Cite

Fully understanding the mechanisms of signaling proteins such as G protein-coupled receptors (GPCRs) will require the characterization of their conformational states and the pathways connecting those states. The recent crystal structures of the ␤2-and ␤1-adrenergic receptors in a nominally inactive state constituted a major advance toward this goal, but also raised new questions. Although earlier biochemical observations had suggested that these receptors possessed a set of contacts between helices 3 and 6, known as the ionic lock, which was believed to form a molecular switch for receptor activation, the crystal structures lacked these contacts. The unexpectedly broken ionic lock has raised questions about the true conformation(s) of the inactive state and the role of the ionic lock in receptor activation and signaling. To address these questions, we performed microsecond-timescale molecular dynamics simulations of the ␤2-adrenergic receptor (␤2AR) in multiple wild-type and mutant forms. In wild-type simulations, the ionic lock formed reproducibly, bringing the intracellular ends of helices 3 and 6 together to adopt a conformation similar to that found in inactive rhodopsin. Our results suggest that inactive ␤2AR exists in equilibrium between conformations with the lock formed and the lock broken, whether or not the cocrystallized ligand is present. These findings, along with the formation of several secondary structural elements in the ␤2AR loops during our simulations, may provide a more comprehensive picture of the inactive state of the ␤-adrenergic receptors, reconciling the crystal structures with biochemical studies.GPCR ͉ ionic lock ͉ molecular dynamics

show abstract

Section: Concluding Remarks)mentioning

confidence: 99%

mentioning

confidence: 99%

Identification of two distinct inactive conformations of the β ₂ -adrenergic receptor reconciles structural and biochemical observations

Dror

Arlow

Borhani

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

291

236

View full text Add to dashboard Cite

show abstract

“…G protein-coupled receptors (GPCRs) are the largest family of membrane surface receptors, essential for signal transduction in central nervous system, and a preferred therapeutic target for psychiatric and neurological disorders (Gilchrist, 2007;Kobilka and Deupi, 2007). The SREB (Super Conserved Receptor Expressed in Brain) family-SREB1 (GPR27), SREB2 (GPR85), and SREB3 (GPR173)-is a particular subfamily of the GPCRs.…”

Section: Introductionmentioning

confidence: 99%

Effect of Schizophrenia Risk-Associated Alleles in SREB2 (GPR85) on Functional MRI Phenotypes in Healthy Volunteers

Radulescu¹,

Sambataro

Mattay

et al. 2012

Neuropsychopharmacol

View full text Add to dashboard Cite

Genetic variants in GPR85 (SREB2: rs56080411 and rs56039557) have been associated with risk for schizophrenia. Here, we test the hypothesis that these variants impact on brain function in normal subjects, measured with functional magnetic resonance imaging (fMRI) paradigms that target regions with greatest SREB2 expression (hippocampal formation and amygdaloid complex). During a facial emotion recognition paradigm, a significant interaction of rs56080411 genotype by sex was found in the left amygdaloid complex (male risk allele carriers showed less activation than male homozygotes for the non-risk allele, while females showed the opposite pattern). During aversive encoding of an emotional memory paradigm, we found that risk allele carriers for rs56080411 had greater activation in the right inferior frontal gyrus. Trends in the same direction were present for rs56039557 in the right occipital cortex and right fusiform gyrus. During a working memory paradigm, a significant sex-by-genotype interaction was found with male risk allele carriers of rs56080411 having inefficient activation within the left dorsolateral prefrontal cortex (DLPFC), compared with same sex non-risk carriers, while females revealed an opposite pattern, despite similar levels of performance. These data suggest that risk-associated variants in SREB2 are associated with phenotypes similar to those found in patients with schizophrenia in the DLPFC and the amygdala of males, while the pattern is opposite in females. The findings in females and during the emotional memory paradigm are consistent with modulation by SREB2 of brain circuitries implicated in mood regulation and may be relevant to neuropsychiatric conditions other than schizophrenia.

show abstract

“…However, even rhodopsin has been shown to be structurally more dynamic in detergent solution than in lipid bilayers (5), and such flexibility is more pronounced for GPCRs that bind to diffusible ligands. Another obstacle to structural analysis, and especially to the formation of well ordered crystals, arises from the conformational heterogeneity of these receptors (6,7). The active agonist-bound state of GPCRs is normally found to be intrinsically less stable than the inactive antagonist-bound state, probably reflecting the receptor requirement for higher flexibility in its active state (8).…”

mentioning

confidence: 99%

“…The active agonist-bound state of GPCRs is normally found to be intrinsically less stable than the inactive antagonist-bound state, probably reflecting the receptor requirement for higher flexibility in its active state (8). Agonist binding to the receptor triggers the recruitment of G ␣ protein binding to the intracellular side of the receptor, possibly via a succession of different conformations (7,9,10).…”

mentioning

confidence: 99%

Co-evolving stability and conformational homogeneity of the human adenosine A _2a receptor

Magnani

Shibata

Serrano-Vega

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

209

278

View full text Add to dashboard Cite

Structural studies on mammalian integral membrane proteins have long been hampered by their instability in detergent. This is particularly true for the agonist conformation of G protein-coupled receptors (GPCRs), where it is thought that the movement of helices that occurs upon agonist binding results in a looser and less stable packing in the protein. Here, we show that mutagenesis coupled to a specific selection strategy can be used to stabilize the agonist and antagonist conformations of the adenosine A2a receptor. Of the 27 mutations identified that improve the thermostability of the agonist conformation, only three are also present in the 17 mutations identified that improve the thermostability of the antagonist conformation, suggesting that the selection strategies used were specific for each conformation. Combination of the stabilizing mutations for the antagonist-or agonist-binding conformations resulted in mutants that are more stable at higher temperatures than the wild-type receptor by 17°C and 9°C, respectively. The mutant receptors both showed markedly improved stability in short-chain alkyl-glucoside detergents compared with the wild-type receptor, which will facilitate their structural analysis.conformational thermostabilization ͉ G protein-coupled receptor ͉ membrane protein G protein-coupled receptors (GPCRs) represent one of the largest single families of integral membrane proteins in the human genome and bind multifarious ligands that mediate many physiological processes, which explains why GPCRs represent a major proportion of drug targets (1). The binding of an extracellular ligand to a GPCR promotes coupling of the receptor to trimeric G proteins, situated on the intracellular side of the plasma membrane, triggering a signaling cascade. Despite sharing common features such as seven transmembrane helices and conserved signatures in their amino acid sequence (2), the sequence homology between different GPCRs is rather low. Detailed structure determination of GPCRs is therefore required to elucidate the mechanism of receptor activation to improve the design of both agonist and antagonist ligands of medical relevance.For many years, crystallographic studies of GPCRs were limited to rhodopsin because of its abundance in native sources (retina) and its intrinsic stability in the dark state (3, 4). However, even rhodopsin has been shown to be structurally more dynamic in detergent solution than in lipid bilayers (5), and such flexibility is more pronounced for GPCRs that bind to diffusible ligands. Another obstacle to structural analysis, and especially to the formation of well ordered crystals, arises from the conformational heterogeneity of these receptors (6, 7). The active agonist-bound state of GPCRs is normally found to be intrinsically less stable than the inactive antagonist-bound state, probably reflecting the receptor requirement for higher flexibility in its active state (8). Agonist binding to the receptor triggers the recruitment of G ␣ protein binding to the intracellular side of the...

show abstract

Conformational complexity of G-protein-coupled receptors

Cited by 644 publications

References 38 publications

Identification of two distinct inactive conformations of the β ₂ -adrenergic receptor reconciles structural and biochemical observations

Identification of two distinct inactive conformations of the β ₂ -adrenergic receptor reconciles structural and biochemical observations

Effect of Schizophrenia Risk-Associated Alleles in SREB2 (GPR85) on Functional MRI Phenotypes in Healthy Volunteers

Co-evolving stability and conformational homogeneity of the human adenosine A _2a receptor

Contact Info

Product

Resources

About

Conformational complexity of G-protein-coupled receptors

Cited by 644 publications

References 38 publications

Identification of two distinct inactive conformations of the β 2 -adrenergic receptor reconciles structural and biochemical observations

Identification of two distinct inactive conformations of the β 2 -adrenergic receptor reconciles structural and biochemical observations

Effect of Schizophrenia Risk-Associated Alleles in SREB2 (GPR85) on Functional MRI Phenotypes in Healthy Volunteers

Co-evolving stability and conformational homogeneity of the human adenosine A 2a receptor

Contact Info

Product

Resources

About

Identification of two distinct inactive conformations of the β ₂ -adrenergic receptor reconciles structural and biochemical observations

Identification of two distinct inactive conformations of the β ₂ -adrenergic receptor reconciles structural and biochemical observations

Co-evolving stability and conformational homogeneity of the human adenosine A _2a receptor