scholarly journals AmOctα2R: Functional Characterization of a Honeybee Octopamine Receptor Inhibiting Adenylyl Cyclase Activity

2020 ◽  
Vol 21 (24) ◽  
pp. 9334
Author(s):  
Wolfgang Blenau ◽  
Joana Alessandra Wilms ◽  
Sabine Balfanz ◽  
Arnd Baumann
Keyword(s):  
Biogenic Amines ◽  
Functional Characterization ◽  
Eukaryotic Cell ◽  
Intracellular Camp ◽  
Octopamine Receptors ◽  
Pharmacological Data ◽  
Large Protein Family ◽  
Octopamine Receptor ◽  
G Protein Coupled

The catecholamines norepinephrine and epinephrine are important regulators of vertebrate physiology. Insects such as honeybees do not synthesize these neuroactive substances. Instead, they use the phenolamines tyramine and octopamine for similar physiological functions. These biogenic amines activate specific members of the large protein family of G protein-coupled receptors (GPCRs). Based on molecular and pharmacological data, insect octopamine receptors were classified as either α- or β-adrenergic-like octopamine receptors. Currently, one α- and four β-receptors have been molecularly and pharmacologically characterized in the honeybee. Recently, an α2-adrenergic-like octopamine receptor was identified in Drosophila melanogaster (DmOctα2R). This receptor is activated by octopamine and other biogenic amines and causes a decrease in intracellular cAMP ([cAMP]i). Here, we show that the orthologous receptor of the honeybee (AmOctα2R), phylogenetically groups in a clade closely related to human α2-adrenergic receptors. When heterologously expressed in an eukaryotic cell line, AmOctα2R causes a decrease in [cAMP]i. The receptor displays a pronounced preference for octopamine over tyramine. In contrast to DmOctα2R, the honeybee receptor is not activated by serotonin. Its activity can be blocked efficiently by 5-carboxamidotryptamine and phentolamine. The functional characterization of AmOctα2R now adds a sixth member to this subfamily of monoaminergic receptors in the honeybee and is an important step towards understanding the actions of octopamine in honeybee behavior and physiology.

The characterization of presynaptic octopamine receptors modulating octopamine release from an identified neurone in the locust

1998 ◽  
Vol 201 (13) ◽  
pp. 2053-2060 ◽  
Author(s):  
KM Howell ◽  
PD Evans
Keyword(s):  
Central Nervous System ◽  
Rank Order ◽  
Muscle Preparation ◽  
Pharmacological Profile ◽  
Octopamine Receptors ◽  
High K ◽  
Wide Range ◽  
Octopamine Receptor ◽  
Dorsal Unpaired Median

Octopamine release has been demonstrated from the dorsal unpaired median neurone to the locust extensor-tibiae muscle (DUMETi) in response to high-[K+] saline. Here, we provide evidence for the existence of presynaptic inhibitory autoreceptors for octopamine on the DUMETi terminals and report on their pharmacological profile. Octopamine release was initiated by exposure to high-[K+] saline (0. 1 mol l-1) and measured using a radioenzyme assay for octopamine. Octopamine receptor antagonists (10(-4 )mol l-1) potentiated the high-[K+]-mediated release of octopamine with the following rank order of potency: phentolamine = metoclopramide > mianserin = chlorpromazine > cyproheptadine > yohimbine. Octopamine receptor agonists (10(-4 )mol l-1) inhibited the high-[K+]-mediated release of octopamine with the following rank order of potency: naphazoline > tolazoline > clonidine. Thus, the octopamine autoreceptors on the DUMETi terminals are much closer pharmacologically to the pre-and postsynaptic OCTOPAMINE2 receptors in the locust extensor-tibiae muscle preparation than to the OCTOPAMINE3 receptors from the locust central nervous system. The results suggest that there is likely to be more than one type of insect neuronal octopamine receptor. It is also likely that presynaptic modulation of octopamine release may be confined to octopamine receptors since a wide range of other putative modulatory substances did not produce this effect.

In-vitro folding and functional characterization of the extracellular domain of G protein-coupled receptors

2002 ◽  
Vol 30 (3) ◽  
pp. A60-A60
Author(s):  
A. Kuntzsch ◽  
U. Grauschopf ◽  
A. Bazarsuren ◽  
K. Wenig ◽  
H. Lilie ◽  
...  
Keyword(s):  
G Protein ◽  
Functional Characterization ◽  
Extracellular Domain ◽  
G Protein Coupled Receptors ◽  
G Protein Coupled

scholarly journals Functional characterization of the TAS2R38 bitter taste receptor for phenylthiocarbamide in colobine monkeys

2017 ◽  
Vol 13 (1) ◽  
pp. 20160834 ◽  
Author(s):  
Laurentia Henrieta Permita Sari Purba ◽  
Kanthi Arum Widayati ◽  
Kei Tsutsui ◽  
Nami Suzuki-Hashido ◽  
Takashi Hayakawa ◽  
...  
Keyword(s):  
Bitter Taste ◽  
Functional Characterization ◽  
Taste Receptor ◽  
Synonymous Mutations ◽  
Natural Toxins ◽  
Colobine Monkeys ◽  
Functional Analyses ◽  
G Protein Coupled

Bitterness perception in mammals is mostly directed at natural toxins that induce innate avoidance behaviours. Bitter taste is mediated by the G protein-coupled receptor TAS2R, which is located in taste cell membranes. One of the best-studied bitter taste receptors is TAS2R38, which recognizes phenylthiocarbamide (PTC). Here we investigate the sensitivities of TAS2R38 receptors to PTC in four species of leaf-eating monkeys (subfamily Colobinae). Compared with macaque monkeys (subfamily Cercopithecinae), colobines have lower sensitivities to PTC in behavioural and in vitro functional analyses. We identified four non-synonymous mutations in colobine TAS2R38 that are responsible for the decreased sensitivity of the TAS2R38 receptor to PTC observed in colobines compared with macaques. These results suggest that tolerance to bitterness in colobines evolved from an ancestor that was sensitive to bitterness as an adaptation to eating leaves.

scholarly journals Identification and Functional Characterization of Two Orphan G-protein-coupled Receptors for Adipokinetic Hormones from SilkwormBombyx mori

2011 ◽  
Vol 286 (49) ◽  
pp. 42390-42402 ◽  
Author(s):  
Ying Shi ◽  
Haishan Huang ◽  
Xiaoyan Deng ◽  
Xiaobai He ◽  
Jingwen Yang ◽  
...  
Keyword(s):  
G Protein ◽  
Functional Characterization ◽  
G Protein Coupled Receptors ◽  
G Protein Coupled

NMR investigation of protein–ligand interactions for G-protein coupled receptors

2019 ◽  
Vol 11 (14) ◽  
pp. 1811-1825 ◽  
Author(s):  
Claire Raingeval ◽  
Isabelle Krimm
Keyword(s):  
Conformational Changes ◽  
Functional Characterization ◽  
Allosteric Modulation ◽  
G Protein Coupled Receptors ◽  
Nmr Studies ◽  
Protein Ligand Interactions ◽  
Ligand Interactions ◽  
Therapeutic Compounds ◽  
G Protein Coupled

In this review, we report NMR studies of ligand–GPCR interactions, including both ligand-observed and protein-observed NMR experiments. Published studies exemplify how NMR can be used as a powerful tool to design novel GPCR ligands and investigate the ligand-induced conformational changes of GPCRs. The strength of NMR also lies in its capability to explore the diverse signaling pathways and probe the allosteric modulation of these highly dynamic receptors. By offering unique opportunities for the identification, structural and functional characterization of GPCR ligands, NMR will likely play a major role for the generation of novel molecules both as new tools for the understanding of the GPCR function and as therapeutic compounds for a large diversity of pathologies.

scholarly journals Functional Characterization of Three G Protein-coupled Receptors for Pigment Dispersing Factors inCaenorhabditis elegans

2008 ◽  
Vol 283 (22) ◽  
pp. 15241-15249 ◽  
Author(s):  
Tom Janssen ◽  
Steven J. Husson ◽  
Marleen Lindemans ◽  
Inge Mertens ◽  
Suzanne Rademakers ◽  
...  
Keyword(s):  
G Protein ◽  
Functional Characterization ◽  
G Protein Coupled Receptors ◽  
G Protein Coupled

scholarly journals Transcriptional and Functional Characterization of the G Protein-Coupled Receptor Repertoire of Gastric Somatostatin Cells

Endocrinology ◽  
2015 ◽  
Vol 156 (11) ◽  
pp. 3909-3923 ◽  
Author(s):  
Kristoffer L. Egerod ◽  
Maja S. Engelstoft ◽  
Mari L. Lund ◽  
Kaare V. Grunddal ◽  
Mirabella Zhao ◽  
...  
Keyword(s):  
G Protein ◽  
Functional Characterization ◽  
G Protein Coupled Receptor ◽  
Receptor Repertoire ◽  
Somatostatin Cells ◽  
G Protein Coupled

scholarly journals Functional Characterization of Melanocortin-3 Receptor Variants Identify a Loss-of-Function Mutation Involving an Amino Acid Critical for G Protein-Coupled Receptor Activation

2004 ◽  
Vol 89 (8) ◽  
pp. 3936-3942 ◽  
Author(s):  
Ya-Xiong Tao ◽  
Deborah L. Segaloff
Keyword(s):  
G Protein ◽  
Functional Characterization ◽  
Receptor Activation ◽  
Dominant Negative ◽  
Supporting Evidence ◽  
Loss Of Function ◽  
Melanocortin 4 Receptor ◽  
Dominant Negative Activity ◽  
G Protein Coupled

Although melanocortin-4 receptor mutations are the cause of the most common monogenic form of obesity, the involvement of the melanocortin-3 receptor (MC3R) in the pathogenesis of obesity is unknown. Earlier studies failed to identify any mutations in obese patients except for the identification of two variants (K6T and I81V) that likely represent polymorphisms. However, a potential mutation (I183N) was recently reported from patients having high-fat contents. We report here the functional characterization of these variants. We show that K6T and I81V have ligand binding and signaling properties similar to wild-type (wt) MC3R, indicating that they are indeed polymorphisms. However, the other variant, I183N, completely lacks signaling in response to agonist stimulation, although it binds ligand with normal affinity and with only slightly decreased capacity. Coexpression of the wt and I183N MC3Rs showed that I183N does not exert dominant-negative activity on wt MC3R. These results provide supporting evidence for the hypothesis proposed in the original case report that MC3R mutation might be a genetic factor that confers susceptibility to obesity, likely due to haploinsufficiency. Further mutations at I183 revealed a discrete requirement for I183 in agonist-induced MC3R activation. The corresponding residue is also important for agonist-induced human melanocortin-4 receptor and lutropin receptor activation. In summary, we identify a residue that is critical for activation of G protein-coupled receptors.

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