Structural Basis for Allosteric Regulation of GPCRs by Sodium Ions

Liu, Wei; Chun, Eugene; Thompson, Allison; Chubukov, Pavel; Xu, Fei; Katritch, Vsevolod; Han, Gye Won; Roth, Christopher B.; Heitman, Laura H.; IJzerman, Adriaan P.; Cherezov, Vadim; Stevens, Raymond C.

doi:10.1126/science.1219218

Cited by 882 publications

(1,355 citation statements)

References 56 publications

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“…Similar allosteric modulation of receptor function has been demonstrated in diverse membrane protein families, including G-protein-coupled receptors, receptor tyrosine kinases, and proton channels (37,39,(41)(42)(43)(44), as well as soluble cytoplasmic proteins containing lipid-targeting domains (45,46). Lipids impact the structure and function of membrane-embedded or membrane-associated proteins either through bulk effects mediated by the phospholipid bilayer or through binding of lipid molecules at specific sites (40,(47)(48)(49)(50). Interestingly, from our study, we conclude that lipid effects in EnvZ operate predominantly through peripheral interactions between nonembedded cytoplasmic domains and the lipid membrane.…”

Section: Discussion Lipids As Allosteric Modulators Of Membrane Protementioning

confidence: 72%

Lipid-Mediated Regulation of Embedded Receptor Kinases via Parallel Allosteric Relays

Ghosh

Wang

Ramesh

et al. 2017

Biophysical Journal

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Membrane-anchored receptors are essential cellular signaling elements for stimulus sensing, propagation, and transmission inside cells. However, the contributions of lipid interactions to the function and dynamics of embedded receptor kinases have not been described in detail. In this study, we used amide hydrogen/deuterium exchange mass spectrometry, a sensitive biophysical approach, to probe the dynamics of a membrane-embedded receptor kinase, EnvZ, together with functional assays to describe the role of lipids in receptor kinase function. Our results reveal that lipids play an important role in regulating receptor function through interactions with transmembrane segments, as well as through peripheral interactions with nonembedded domains. Specifically, the lipid membrane allosterically modulates the activity of the embedded kinase by altering the dynamics of a glycine-rich motif that is critical for phosphotransfer from ATP. This allostery in EnvZ is independent of membrane composition and involves direct interactions with transmembrane and periplasmic segments, as well as peripheral interactions with nonembedded domains of the protein. In the absence of the membrane-spanning regions, lipid allostery is propagated entirely through peripheral interactions. Whereas lipid allostery impacts the phosphotransferase function of the kinase, extracellular stimulus recognition is mediated via a four-helix bundle subdomain located in the cytoplasm, which functions as the osmosensing core through osmolality-dependent helical stabilization. Our findings emphasize the functional modularity in a membrane-embedded kinase, separated into membrane association, phosphotransferase function, and stimulus recognition. These components are integrated through long-range communication relays, with lipids playing an essential role in regulation.

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Section: Discussion Lipids As Allosteric Modulators Of Membrane Protementioning

confidence: 72%

Lipid-Mediated Regulation of Embedded Receptor Kinases via Parallel Allosteric Relays

Ghosh

Wang

Ramesh

et al. 2017

Biophysical Journal

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“…Conversely, the most cooperative mGlu 4 PAMs according to the FRET-based sensor experiments (PHCCC, VU0364770, VU0364439, VU0415374, and TC-N 22A) reside in a second pocket pointing toward a site homologous to the sodium binding site identified in many class A GPCRs (41). The high-resolution GPCR structures of the A2A-adenosine receptor (60) PAMs activate the receptor by their intrinsic agonist activity (t B , red arrow) and enhance agonistinduced receptor activation through positive cooperativity (a, b, blue arrows). The intrinsic agonist activity of mGlu 4 PAMs could be linked to the binding in a pocket homologous to the orthosteric binding site of class A GPCRs (in red), whereas the cooperativity could result from the binding into a secondary pocket (in blue) matching the Na + binding pocket of class A GPCRs.…”

Section: Discussionmentioning

confidence: 99%

Overlapping binding sites drive allosteric agonism and positive cooperativity in type 4 metabotropic glutamate receptors

et al. 2014

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Type 4 metabotropic glutamate (mGlu 4 ) receptors are emerging targets for the treatment of various disorders. Accordingly, numerous mGlu 4 -positive allosteric modulators (PAMs) have been identified, some of which also display agonist activity. To identify the structural bases for their allosteric action, we explored the relationship between the binding pockets of mGlu 4 PAMs with different chemical scaffolds and their functional properties. By use of innovative mGlu 4 biosensors and second-messenger assays, we show that all PAMs enhance agonist action on the receptor through different degrees of allosteric agonism and positive cooperativity. For example, whereas VU0155041 and VU0415374 display equivalent efficacies [log(t B ) = 1.15 6 0.38 and 1.25 6 0.44, respectively], they increase the ability of L-AP4 to stabilize the active conformation of the receptor by 4 and 39 times, respectively. Modeling and docking studies identify 2 overlapping binding pockets as follows: a first site homologous to the pocket of natural agonists of class A GPCRs linked to allosteric agonism and a second one pointing toward a site topographically homologous to the Na + binding pocket of class A GPCRs, occupied by PAMs exhibiting the strongest cooperativity. These results reveal that intrinsic efficacy and cooperativity of mGlu 4 PAMs are correlated with their binding mode, and vice versa, integrating structural and functional knowledge from different GPCR classes.-Rovira, X., Malhaire, F., Scholler, P., Rodrigo, J., Gonzalez-Bulnes, P., Llebaria, A., Pin, J.-P., Giraldo, J., Goudet, C. Overlapping binding sites drive allosteric agonism and positive cooperativity in type 4 metabotropic glutamate receptors. FASEB J. 29, 116-130 (2015). www.fasebj.org

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“…Distinct conformational changes occur during activation of these receptors, including reorganizations of inner protein hydrogen bonding networks, which could be in contact with internal waters 5,6 . An important step forward came from the recent high-resolution crystal structures of the A 2A adenosine receptor (A 2A R) and the delta opioid receptor (dOR), which revealed internal ordered water molecules that could be crucial for GPCR activation 7,8 . On the basis of their crystal structures, Liu et al 7 proposed that the A 2A R in the non-activated state contains a nearly continuous internal water channel, which is disrupted in the activated receptor.…”

mentioning

confidence: 99%

“…An important step forward came from the recent high-resolution crystal structures of the A 2A adenosine receptor (A 2A R) and the delta opioid receptor (dOR), which revealed internal ordered water molecules that could be crucial for GPCR activation 7,8 . On the basis of their crystal structures, Liu et al 7 proposed that the A 2A R in the non-activated state contains a nearly continuous internal water channel, which is disrupted in the activated receptor. However, this detailed suggestion on the extension of the internal water channel is not conclusive for several reasons: (1) As is shown in this article, the A 2A receptor's internal water molecules are quite mobile, which exclude determination of their precise spatial localization within the protein's structural framework.…”

mentioning

confidence: 99%

Activation of G-protein-coupled receptors correlates with the formation of a continuous internal water pathway

et al. 2014

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Recent crystal structures of G-protein-coupled receptors (GPCRs) have revealed ordered internal water molecules, raising questions about the functional role of those waters for receptor activation that could not be answered by the static structures. Here, we used molecular dynamics simulations to monitor-at atomic and high temporal resolutionconformational changes of central importance for the activation of three prototypical GPCRs with known crystal structures: the adenosine A 2A receptor, the b 2 -adrenergic receptor and rhodopsin. Our simulations reveal that a hydrophobic layer of amino acid residues next to the characteristic NPxxY motif forms a gate that opens to form a continuous water channel only upon receptor activation. The highly conserved tyrosine residue Y 7.53 undergoes transitions between three distinct conformations representative of inactive, G-protein activated and GPCR metastates. Additional analysis of the available GPCR crystal structures reveals general principles governing the functional roles of internal waters in GPCRs.

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Structural Basis for Allosteric Regulation of GPCRs by Sodium Ions

Cited by 882 publications

References 56 publications

Lipid-Mediated Regulation of Embedded Receptor Kinases via Parallel Allosteric Relays

Lipid-Mediated Regulation of Embedded Receptor Kinases via Parallel Allosteric Relays

Overlapping binding sites drive allosteric agonism and positive cooperativity in type 4 metabotropic glutamate receptors

Activation of G-protein-coupled receptors correlates with the formation of a continuous internal water pathway

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