Involvement of the Carboxyl Terminus of the Third Intracellular Loop of the Cannabinoid CB1 Receptor in Constitutive Activation of G<sub>s</sub>

Abadji, Vasiliki; Lucas‐Lenard, Jean; Chin, Chen-Ni; Kendall, Debra A.

doi:10.1046/j.1471-4159.1999.0722032.x

Cited by 91 publications

(66 citation statements)

References 31 publications

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“…One notion of the present study is that the lack of conformational constraint between TM-V and TM-III is associated with high constitutive activity as in the wild-type ghrelin receptor. This is indeed the case because a number of receptors lacking ECL2b, such as the CB1, MC4, and sphingosine 1-phosphate 1 receptors, are highly constitutively active (44,(61)(62)(63).…”

Section: Discussionmentioning

confidence: 99%

Modulation of Constitutive Activity and Signaling Bias of the Ghrelin Receptor by Conformational Constraint in the Second Extracellular Loop

Mokrosiński

Frimurer

Sivertsen

et al. 2012

Journal of Biological Chemistry

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Background: A natural Glu for Ala variant in the ghrelin receptor extracellular loop 2 selectively eliminates constitutive signaling. Results: Computational chemistry and mutational analysis show that charged residues and metal ion sites that induce ␣-helix formation in ECL2 prevent constitutive signaling. Conclusion: Flexibility of ECL2 connecting TM-III and TM-V is essential for spontaneous receptor signaling. Significance: Clarification of ECL2 structural constraint is important for receptor signaling.

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Section: Discussionmentioning

confidence: 99%

Modulation of Constitutive Activity and Signaling Bias of the Ghrelin Receptor by Conformational Constraint in the Second Extracellular Loop

Mokrosiński

Frimurer

Sivertsen

et al. 2012

Journal of Biological Chemistry

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“…Transfection was carried out using the calcium phosphate precipitation method (Chen and Okayama, 1987). Membranes of transfected cells expressing the wild-type or mutant receptors were prepared as described previously (Abadji et al, 1999). In brief, 24 h after transfection, cells were harvested, washed twice with phosphate-buffered saline (PBS), and resuspended in PBS containing 4-(2-aminoethyl)benzenesulfonyl fluoride, pepstatin A, E-64, bestatin, leupeptin, and aprotinin as protease inhibitors (Sigma, St. Louis, MO).…”

Section: Cb1mentioning

confidence: 99%

Dual Role of the Second Extracellular Loop of the Cannabinoid Receptor 1: Ligand Binding and Receptor Localization

Ahn

Bertalovitz²,

Mierke³

et al. 2009

Mol Pharmacol

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112

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The seven transmembrane ␣-helices of G protein-coupled receptors (GPCRs) are the hallmark of this superfamily. Intrahelical interactions are critical to receptor assembly and, for the GPCR subclass that binds small molecules, ligand binding. Most research has focused on identifying the ligand binding pocket within the helical bundle, whereas the role of the extracellular loops remains undefined. Molecular modeling of the cannabinoid receptor 1 (CB1) extracellular loop 2 (EC2), however, suggests that EC2 is poised for key interactions. To test this possibility, we employed alanine scanning mutagenesis of CB1 EC2 and identified two distinct regions critical for ligand binding, G protein coupling activity, and receptor trafficking. Receptors with mutations in the N terminus of EC2 (W255A, N256A) were retained in the endoplasmic reticulum and did not bind the agonist (1R,3R,In contrast, the C terminus of EC2 differentiates agonist and inverse agonist; the P269A, H270A, and I271A receptors exhibited diminished binding for several agonists but bound inverse agonists SR141716A,, and 4-[6-methoxy-2-(4-methoxyphenyl)-benzofuran-3-carbonyl]benzonitrile (LY320135) with wild-type receptor affinity. The F268A receptor involving substitution in the Cys-X-X-X-Ar motif, displayed both impaired localization and ligand binding. Other amino acid substitutions at position 268 revealed that highly hydrophobic residues are required to accomplish both functions. It is noteworthy that a F268W receptor was trafficked to the cell surface yet displayed differential binding preference for inverse agonists comparable with the P269A, H270A, and I271A receptors. The findings are consistent with a dual role for EC2 in stabilizing receptor assembly and in ligand binding.The human cannabinoid receptor 1 (CB1) is a member of the rhodopsin-like G protein-coupled receptor (GPCR) family, members of which comprise seven transmembrane helices (TMs) connected by three intracellular loops and three extracellular loops. In addition to binding ⌬ 9 -tetrahydrocannabinol (⌬ 9 -THC), the psychoactive constituent of Cannabis sativa, several endogenous cannabinoid receptor agonists have been identified, including anandamide (arachidonoylethanolamide), 2-arachidonoylglycerol, and 2-arachidonylglyceryl ether (noladin ether). CB1 also binds a variety of synthetic cannabimimetic compounds such as the nonclassic agonist CP55940, a bicyclic analog of ⌬ 9 -THC, the classic agonist HU-210, and the selective inverse agonists SR141716A (also known as rimonabant), AM251, and LY320135. Upon activation, CB1 modulates synaptic transmission, ultimately playing a role in analgesia, anxiety, feeding behavior, and movement disorders (Porter and Felder, 2001;Howlett et al., 2002). Thus, understanding the features of CB1 critical for ligand binding and receptor localization is important for developing its therapeutic potential.Molecular modeling analyses of ligand-receptor interactions involving CB1 are consistent with the idea that the N-(piperidin-1-yl)-5-(4-iodophenyl...

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“…[39][40][41] A more complete appreciation of WIN and SR effects on filopodia length is aided by considering distributional changes (Figs. 3 and 4).…”

Section: Wwwlandesbiosciencecommentioning

confidence: 99%

Altered patterns of filopodia production in CHO cells heterologously expressing zebra finch CB₁cannabinoid receptors

Soderstrom

Zhang

Wilson

2012

Cell Adhesion & Migration

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Abbreviations: CHO cells, Chinese hamster ovary cells; DMSO, dimethyl sulfoxide; M/C, membrane:cytoplasm; PBS, phosphate-buffered saline; SR, the CB 1 receptor-selective antagonist/inverse agonist SR141716A; WIN, the cannabinoid agonist WIN55212-2; zfCB1, zebra finch CB 1 cannabinoid receptorRecent findings indicate that cannabinoid-altered vocal development involves elevated densities of dendritic spines in a subset of brain regions involved in zebra finch song learning and production suggesting that cannabinoid receptor activation may regulate cell structure. Here we report that activation of zebra finch CB 1 receptors (zfCB 1 , delivered by a lentivector to CHO cells) produces dose-dependent biphasic effects on the mean length of filopodia expressed: Low agonist concentrations (3 nM WIN55212-2) increase lengths while higher concentrations reduce them. In contrast, treatment of zfCB 1 -expressing cells with the antagonist/inverse agonist SR141716A causes increases in both mean filopodia length and number at 30 and 100 nM. These results demonstrate that CB 1 receptor activation can differentially influence filiopodia elongation depending on dose, and demonstrate that manipulation of cannabinoid receptor activity is capable of modulating cell morphology.

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Involvement of the Carboxyl Terminus of the Third Intracellular Loop of the Cannabinoid CB1 Receptor in Constitutive Activation of G_s

Cited by 91 publications

References 31 publications

Modulation of Constitutive Activity and Signaling Bias of the Ghrelin Receptor by Conformational Constraint in the Second Extracellular Loop

Modulation of Constitutive Activity and Signaling Bias of the Ghrelin Receptor by Conformational Constraint in the Second Extracellular Loop

Dual Role of the Second Extracellular Loop of the Cannabinoid Receptor 1: Ligand Binding and Receptor Localization

Altered patterns of filopodia production in CHO cells heterologously expressing zebra finch CB₁cannabinoid receptors

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Involvement of the Carboxyl Terminus of the Third Intracellular Loop of the Cannabinoid CB1 Receptor in Constitutive Activation of Gs

Cited by 91 publications

References 31 publications

Modulation of Constitutive Activity and Signaling Bias of the Ghrelin Receptor by Conformational Constraint in the Second Extracellular Loop

Modulation of Constitutive Activity and Signaling Bias of the Ghrelin Receptor by Conformational Constraint in the Second Extracellular Loop

Dual Role of the Second Extracellular Loop of the Cannabinoid Receptor 1: Ligand Binding and Receptor Localization

Altered patterns of filopodia production in CHO cells heterologously expressing zebra finch CB1cannabinoid receptors

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Involvement of the Carboxyl Terminus of the Third Intracellular Loop of the Cannabinoid CB1 Receptor in Constitutive Activation of G_s

Altered patterns of filopodia production in CHO cells heterologously expressing zebra finch CB₁cannabinoid receptors