Molecular Characterization of a Purified 5-HT4 Receptor

Banères, Jean-Louis; Mesnier, Danielle; Martin, Aimée; Joubert, Lara; Dumuis, Aline; Bockaert, Joël

doi:10.1074/jbc.m412009200

Cited by 137 publications

(137 citation statements)

References 32 publications

Supporting

Mentioning

127

Contrasting

Unclassified

Order By: Relevance

“…Mutation of Cys 279 (6.47) to Ala or Tyr (a mutation causing infertility in man) and Asn 315 (7.45) to Ala increases ligand binding affinity for GnRHs from other species and converts them to full agonists [76]. Recent studies have shown that partial agonists stabilize a receptor active conformation differing from that of full agonists, with different signaling capability [6,109]. Taken together these findings suggest that a complex receptor intramolecular interaction network evolved during evolution for selective binding of ligands and G protein activation.…”

Section: Differential Gnrh Receptor Conformations Dictate Different Lmentioning

confidence: 99%

Diversity of actions of GnRHs mediated by ligand-induced selective signaling

Millar

Pawson

Morgan

et al. 2008

Frontiers in Neuroendocrinology

123

View full text Add to dashboard Cite

Geoffrey Wingfield Harris' demonstration of hypothalamic hormones regulating pituitary function led to their structural identification and therapeutic utilization in a wide spectrum of diseases. Amongst these, Gonadotropin Releasing Hormone (GnRH) and its analogs are widely employed in modulating gonadotropin and sex steroid secretion to treat infertility, precocious puberty and many hormone-dependent diseases including endometriosis, uterine fibroids and prostatic cancer. While these effects are all mediated via modulation of the pituitary gonadotrope GnRH receptor and the G q signaling pathway, it has become increasingly apparent that GnRH regulates many extrapituitary cells in the nervous system and periphery. This review focuses on two such examples, namely GnRH analog effects on reproductive behaviors and GnRH analog effects on the inhibition of cancer cell growth. For both effects the relative activities of a range of GnRH analogs is distinctly different from their effects on the pituitary gonadotrope and different signaling pathways are utilized. As there is only a single functional GnRH receptor type in man we have proposed that the GnRH receptor can assume different conformations which have different selectivity for GnRH analogs and intracellular signaling proteins complexes. This ligand-induced selective-signaling recruits certain pathways while by-passing others and has implications in developing more selective GnRH analogs for highly specific therapeutic intervention.

show abstract

Section: Differential Gnrh Receptor Conformations Dictate Different Lmentioning

confidence: 99%

Diversity of actions of GnRHs mediated by ligand-induced selective signaling

Millar

Pawson

Morgan

et al. 2008

Frontiers in Neuroendocrinology

123

View full text Add to dashboard Cite

show abstract

“…The most detailed description of the conformational repertoire that a GPCR can adopt has been obtained in the case of the β 2 -adrenergic receptor with an experimental demonstration of a complex conformational landscape where ligands with distinct pharmacological properties shift the conformation of the receptor from one state to another (4)(5)(6)(7)(8)(9)(10)(11). In the same way, we showed that ligands with different efficacies stabilize different conformations of the serotonin receptor (12). Despite this wealth of data, understanding of GPCR activation mechanisms, and in particular of the necessary influence of signaling proteins on the receptor conformational repertoire, is still incomplete.…”

mentioning

confidence: 91%

Ligands and signaling proteins govern the conformational landscape explored by a G protein-coupled receptor

Mary

Damian

Louet

et al. 2012

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

Self Cite

View full text Add to dashboard Cite

The dynamic character of G protein-coupled receptors is essential to their function. However, the details of how ligands stabilize a particular conformation to selectively activate a signaling pathway and how signaling proteins affect this conformational repertoire remain unclear. Using a prototypical peptide-activated class A G protein-coupled receptor (GPCR), the ghrelin receptor, reconstituted as a monomer into lipid discs and labeled with a fluorescent conformational reporter, we demonstrate that ligand efficacy and functional selectivity are directly related to different receptor conformations. Of importance, our data bring direct evidence that distinct effector proteins affect the conformational landscape of the ghrelin receptor in different ways. Whereas G proteins affect the balance between active and inactive receptor substates in favor of the active state, agonist-induced arrestin recruitment is accompanied by a marked change in the structural features of the receptor that adopt a conformation different from that observed in the absence of arrestin. In contrast to G proteins and arrestins, μ-AP2 has no significant effect on the organization of the transmembrane core of the receptor. Such a modulation of a GPCR conformational landscape by pharmacologically distinct ligands and effectors provides insights into the structural bases that decisively affect ligand efficacy and subsequent biological responses. This is also likely to have major implications for the design of drugs activating specific GPCR-associated signaling pathways.membrane protein | structural repertoire | biased ligands | constitutive activity M ajor progress has been made in past years in understanding the molecular bases of G protein-coupled receptor (GPCR)-mediated signaling. Spectacular developments in GPCR stabilization and crystallization have resulted in many different crystal structures of active and inactive receptors (1) and ultimately led to the structure of the agonist-activated β 2 -adrenergic receptor in complex with its cognate Gs protein (2). However, these structures still represent unique states, whereas the dynamic character of receptors is essential for their physiological functions. Indeed, many reports point at a model where GPCRs are highly dynamic proteins capable of adopting a large number of conformational states that signal with different efficacies to various pathways (3). The most detailed description of the conformational repertoire that a GPCR can adopt has been obtained in the case of the β 2 -adrenergic receptor with an experimental demonstration of a complex conformational landscape where ligands with distinct pharmacological properties shift the conformation of the receptor from one state to another (4-11). In the same way, we showed that ligands with different efficacies stabilize different conformations of the serotonin receptor (12). Despite this wealth of data, understanding of GPCR activation mechanisms, and in particular of the necessary influence of signaling proteins on the receptor conformationa...

show abstract

“…In general, the receptor transmembrane helices (TMs) rearrange, allowing the intracellular loop region to unfold and to stimulate neighboring G proteins (3,4). Conformational changes include extracellular receptor regions, and a critical role of the second extracellular loop (E2) for GPCR activation and ligand binding has emerged (5)(6)(7)(8)(9). Rational development of agonistic drugs for GPCR activation requires deeper insight into such conformational changes.…”

mentioning

confidence: 99%

Allosteric Small Molecules Unveil a Role of an Extracellular E2/Transmembrane Helix 7 Junction for G Protein-coupled Receptor Activation

Jäger

Schmalenbach

Prilla

et al. 2007

Journal of Biological Chemistry

View full text Add to dashboard Cite

G protein-coupled receptors represent the largest superfamily of cell membrane-spanning receptors. We used allosteric small molecules as a novel approach to better understand conformational changes underlying the inactive-to-active switch in native receptors. Allosteric molecules bind outside the orthosteric area for the endogenous receptor activator. The human muscarinic M 2 acetylcholine receptor is prototypal for the study of allosteric interactions. We measured receptor-mediated G protein activation, applied a series of structurally diverse muscarinic allosteric agents, and analyzed their cooperative effects with orthosteric receptor agonists. A strong negative cooperativity of receptor binding was observed with acetylcholine and other full agonists, whereas a pronounced negative cooperativity of receptor activation was observed with the partial agonist pilocarpine. Applying a newly synthesized allosteric tool, point mutated receptors, radioligand binding, and a three-dimensional receptor model, we found that the deviating allosteric/orthosteric interactions are mediated through the core region of the allosteric site. A key epitope is M 2 Trp 422 in position 7.35 that is located at the extracellular top of transmembrane helix 7 and that contacts, in the inactive receptor, the extracellular loop E2. Trp 7.35 is critically involved in the divergent allosteric/orthosteric cooperativities with acetylcholine and pilocarpine, respectively. In the absence of allosteric agents, Trp 7.35 is essential for receptor binding of the full agonist and for receptor activation by the partial agonist. This study provides first evidence for a role of an allosteric E2/transmembrane helix 7 contact region for muscarinic receptor activation by orthosteric agonists. G protein-coupled receptors (GPCRs)4 have outstanding importance as targets for drug action (1, 2). Conformational changes underlying the inactive-to-active receptor switch in GPCRs are in the focus of current research. In general, the receptor transmembrane helices (TMs) rearrange, allowing the intracellular loop region to unfold and to stimulate neighboring G proteins (3, 4). Conformational changes include extracellular receptor regions, and a critical role of the second extracellular loop (E2) for GPCR activation and ligand binding has emerged (5-9). Rational development of agonistic drugs for GPCR activation requires deeper insight into such conformational changes. Because GPCRs are hardly accessible for crystallization, indirect approaches are applied that often involve modification of the receptor protein such as receptor mutagenesis, introduction of metal ion sites or disulfide bridges, or covalent linkage of moieties for fluorescence resonance energy transfer.Allosteric small molecules allow the study of native receptors. An increasing number of GPCRs is known to contain allosteric sites (10, 11); cinacalcet is the first allosteric GPCR modulator that has recently entered the market (12). Allosteric sites are located outside the orthosteric area that is occupied...

show abstract

Molecular Characterization of a Purified 5-HT4 Receptor

Cited by 137 publications

References 32 publications

Diversity of actions of GnRHs mediated by ligand-induced selective signaling

Diversity of actions of GnRHs mediated by ligand-induced selective signaling

Ligands and signaling proteins govern the conformational landscape explored by a G protein-coupled receptor

Allosteric Small Molecules Unveil a Role of an Extracellular E2/Transmembrane Helix 7 Junction for G Protein-coupled Receptor Activation

Contact Info

Product

Resources

About