Time-resolved FRET between GPCR ligands reveals oligomers in native tissues

Albizu, Laura; Cottet, Martin; Králíková, Michaela; Stoev, S.; Seyer, René; Brabet, Isabelle; Roux, Thomas; Bazin, Hervé; Bourrier, Emmanuel; Lamarque, Laurent; Breton, Christophe; Rives, M.; Newman, Amy Hauck; Javitch, Jonathan A.; Trinquet, Eric; Manning, Maurice; Pin, Jean‐Philippe; Mouillac, Bernard; Durroux, Thierry

doi:10.1038/nchembio.396

Cited by 303 publications

(305 citation statements)

References 51 publications

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“…This proposal is best illustrated in the heterodimeric GABA B and taste receptors (39,40), as well as in the homodimeric mGlu receptors where an asymmetrical activation of the dimeric 7TM is responsible for G-protein activation (17)(18)(19). This finding is also consistent with the asymmetric functioning reported for many class A GPCR dimers (41)(42)(43). However, these data did not exclude the involvement of the second 7TM associated with the one coupled to the G protein.…”

Section: Isolated 7tm Reconstituted Into Nanodiscs Retains Its Abilitsupporting

confidence: 81%

Distinct roles of metabotropic glutamate receptor dimerization in agonist activation and G-protein coupling

Moustaine

Granier

Doumazane

et al. 2012

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

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158

133

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The eight metabotropic glutamate receptors (mGluRs) are key modulators of synaptic transmission and are considered promising targets for the treatment of various brain disorders. Whereas glutamate acts at a large extracellular domain, allosteric modulators have been identified that bind to the seven transmembrane domain (7TM) of these dimeric G-protein-coupled receptors (GPCRs). We show here that the dimeric organization of mGluRs is required for the modulation of active and inactive states of the 7TM by agonists, but is not necessary for G-protein activation. Monomeric mGlu2, either as an isolated 7TM or in full-length, purified and reconstituted into nanodiscs, couples to G proteins upon direct activation by a positive allosteric modulator. However, only a reconstituted full-length dimeric mGlu2 activates G protein upon glutamate binding, suggesting that dimerization is required for glutamate induced activation. These data show that, even for such well characterized GPCR dimers like mGluR2, a single 7TM is sufficient for G-protein coupling. Despite this observation, the necessity of dimeric architecture for signaling induced by the endogenous ligand glutamate confirms that the central core of signaling complex is dimeric.M etabotropic glutamate receptors (mGluRs) play key roles in the modulation of both excitatory and inhibitory synapses in the brain. These eight G-protein-coupled receptors (GPCRs) represent major targets for pharmaceutical companies in search of new treatments for a variety of neurological and psychiatric disorders (1-3). These receptors are part of the class C GPCR family that also includes the GABA B , calcium sensing, and sweet and umami taste receptors, which are all major targets for drug development (4).The structural complexity of class C GPCRs, compared with rhodopsin-like class A GPCRs, offers multiple possibilities in designing molecules that modulate their activity. Not only are mGluRs strict constitutive dimers (5, 6), but each protomer is composed of several domains (7,8). Agonists bind in a bilobate venus fly-trap domain (VFT) (9), which is linked through a cysteine-rich domain (CRD) to the heptahelical transmembrane domain (7TM) that is responsible for G-protein activation (7). The 7TM is the target of a number of synthetic compounds acting either as negative or positive allosteric modulators (NAMs and PAMs, respectively). Given their ability to finely tune endogenous signaling, such compounds present exciting opportunities for drug development (10).The functional mechanism of such a complex machine remains to be characterized, although some critical steps have been well documented. Previous studies have shown that receptor activation results from the closure of the VFT upon agonist binding (9,(11)(12)(13)(14)(15). This conformational change in the extracellular domain is coupled to a conformational change in the intracellular side of at least one 7TM that is responsible for G-protein coupling (16)(17)(18)(19). The mechanism for allosteric communication between the VFT and 7TM ...

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Section: Isolated 7tm Reconstituted Into Nanodiscs Retains Its Abilitsupporting

confidence: 81%

Distinct roles of metabotropic glutamate receptor dimerization in agonist activation and G-protein coupling

Moustaine

Granier

Doumazane

et al. 2012

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

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158

133

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“…Such allosteric behaviour is also responsible for the gain of opioid receptor function observed when treating a chemokine-opioid receptor heteromer with a chemokine receptor antagonist 46 . These considerations extend beyond the field of chemokine receptors and may be patho-physiologically important 47,48 . However, asymmetry may not be a general requirement for maximal activation of GPCRs, as there are clearly cases in which binding of an agonist to each member of a homomer activates more efficiently G protein coupling 49 .…”

Section: Di(oligo)merization Ofmentioning

confidence: 99%

Evidence for activity-regulated hormone-binding cooperativity across glycoprotein hormone receptor homomers

et al. 2012

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Glycoprotein hormone receptors show strong negative cooperativity. As a consequence, at physiological hormone concentrations, a single agonist binds to a receptor dimer. Here we present evidence that constitutively active receptors lose cooperative allosteric regulation in direct relation with their basal activity. The most constitutive mutants lost nearly all cooperativity and showed an increase of initial tracer binding, reflecting the ability of each protomer to bind with equal affinity. Allosteric interaction between the protomers takes place at the transmembrane domain. The allosteric message resulting from hormone binding to the ectodomain of one protomer travels 'downward' to its transmembrane domain, before affecting the transmembrane domain of the other protomer. This results in transmission of an 'upward' message lowering the binding affinity of the ectodomain of the second protomer. our results demonstrate a direct relation between the conformational changes associated with activation of the transmembrane domain and the allosteric behaviour of glycoprotein hormone receptors dimers.

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“…free vs. receptor-bound ligands). For instance, with labelled antibodies raised against each subunit Hlavackova et al, 2005) or with selective fluorescent ligands (Albizu et al, 2010), time-resolved FRET could be employed to demonstrate the asymmetric activation of various GPCR dimers at the surface of living cells and correlate local structural changes with functional states of ion channels (Kusch et al, 2012).…”

Section: B Fluorescence Spectroscopymentioning

confidence: 99%

“…Also, allosteric modulators of heterodimeric metabotropic glutamate receptors exert different efficacies depending on which subunit they bind to . Asymmetric activation of 5-HT 2C -type seronin and oxytocin class A GPCRs was also demonstrated with disulphide-trapping and radioligand binding as well as with timeresolved FRET and living cells, respectively (Albizu et al, 2010;Mancia et al, 2008) The growth factor receptor family belongs to tyrosine kinases activated by ligand-induced dimerization. The asymmetric dimerization of epidermal growth factor receptors (EGFRs) has been thoroughly studied via XRC and mutational analysis.…”

Section: Structural Symmetry and Transient Asymmetry Of Signalling Prmentioning

confidence: 99%

Asymmetric perturbations of signalling oligomers

Maksay

Tőke

2014

Progress in Biophysics and Molecular Biology

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This review focuses on rapid and reversible noncovalent interactions for symmetric oligomers of tetramers (voltage-gated cation channels, ionotropic glutamate receptor, CNG and CHN channels); pentameric ligand-gated and mechanosensitive channels; higher order oligomers (gap junction channel, chaperonins, proteasome, virus capsid); as well as primary and secondary transporters. In conclusion, asymmetric perturbations seem to play important functional roles in a broad range of communicating networks.

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Time-resolved FRET between GPCR ligands reveals oligomers in native tissues

Cited by 303 publications

References 51 publications

Distinct roles of metabotropic glutamate receptor dimerization in agonist activation and G-protein coupling

Distinct roles of metabotropic glutamate receptor dimerization in agonist activation and G-protein coupling

Evidence for activity-regulated hormone-binding cooperativity across glycoprotein hormone receptor homomers

Asymmetric perturbations of signalling oligomers

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