GPCR Screening via ERK 1/2: A Novel Platform for Screening G Protein–Coupled Receptors

2005 ◽  
Vol 10 (7) ◽  
pp. 730-737 ◽  
Author(s):  
Ronald I. W. Osmond ◽  
Antony Sheehan ◽  
Romana Borowicz ◽  
Emma Barnett ◽  
Georgina Harvey ◽  
...  
Keyword(s):  
G Protein ◽  
High Throughput ◽  
Measurement Techniques ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
G Protein Coupled Receptors ◽  
Drug Candidates ◽  
Gpcr Activation ◽  
Intracellular Ca ◽  
G Protein Coupled

Discovery of novel agonists and antagonists for G protein–coupled receptors (GPCRs) relies heavily on cell-based assays because determination of functional consequences of receptor engagement is often desirable. Currently, there are several key parameters measured to achieve this, including mobilization of intracellular Ca2+ and formation of cyclic adenosine monophosphate or inositol triphosphate. However, no single assay platform is suitable for all situations, and all of the assays have limitations. The authors have developed a new high-throughput homogeneous assay platform for GPCR discovery as an alternative to current assays, which employs detection of phosphorylation of the key signaling molecule p42/44 MAP kinase (ERK 1/2). The authors show that ERK 1/2 is consistently activated in cells stimulated by Gq-coupled GPCRs and provides a new high-throughput platform for screening GPCR drug candidates. The activation of ERK 1/2 in Gq-coupled GPCR systems generates comparable pharmacological data for receptor agonist and antagonist data obtained by other GPCR activation measurement techniques.

scholarly journals A Homogeneous Enzyme Fragment Complementation-Based β-Arrestin Translocation Assay for High-Throughput Screening of G-Protein-Coupled Receptors

2008 ◽  
Vol 13 (8) ◽  
pp. 737-747 ◽  
Author(s):  
Xiaoning Zhao ◽  
Adrie Jones ◽  
Keith R. Olson ◽  
Kun Peng ◽  
Tom Wehrman ◽  
...  
Keyword(s):  
G Protein ◽  
High Throughput ◽  
High Throughput Screening ◽  
Somatostatin Receptor ◽  
Gene Families ◽  
G Protein Coupled Receptors ◽  
Functional Assay ◽  
Gpcr Activation ◽  
Fragment Complementation ◽  
G Protein Coupled

G-protein-coupled receptors (GPCRs) represent one of the largest gene families in the human genome and have long been regarded as valuable targets for small-molecule drugs. The authors describe a new functional assay that directly monitors GPCR activation. It is based on the interaction between β-arrestin and ligand-activated GPCRs and uses enzyme fragment complementation technology. In this format, a GPCR of interest is fused to a small (~4 kDa), optimized α fragment peptide (termed ProLink™) derived from β-galactosidase, and β-arrestin is fused to an N-terminal deletion mutant of β-galactosidase (termed the enzyme acceptor [EA]). Upon activation of the receptor, the β-arrestin-EA fusion protein binds the activated GPCR. This interaction drives enzyme fragment complementation, resulting in an active β-galactosidase enzyme, and thus GPCR activation can be determined by quantifying β-galactosidase activity. In this report, the authors demonstrate the utility of this technology to monitor GPCR activation and validate the approach using a Gαi-coupled GPCR, somatostatin receptor 2. Potential application to high-throughput screens in both agonist and antagonist screening modes is exemplified. ( Journal of Biomolecular Screening 2008:737-747)

scholarly journals A Novel High Throughput Chemiluminescent Assay for the Measurement of Cellular Cyclic Adenosine Monophosphate Levels

2000 ◽  
Vol 5 (4) ◽  
pp. 239-247 ◽  
Author(s):  
Anthony C. Chiulli ◽  
Karen Trompeter ◽  
Michelle Palmer
Keyword(s):  
G Protein ◽  
High Throughput ◽  
High Throughput Screening ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Receptor Activation ◽  
G Protein Coupled Receptor ◽  
Wide Range ◽  
G Protein Coupled ◽  
Camp Levels

The second messenger 3′, 5′-cyclic AMP (cAMP) is a highly regulated molecule that is governed by G protein-coupled receptor activation and other cellular processes. Measurement of cAMP levels in cells is widely used as an indicator of receptor function in drug discovery applications. We have developed a nonradioactive ELISA for the accurate quantitation of cAMP levels produced in cell-based assays. This novel competitive assay utilizes chemiluminescent detection that affords both a sensitivity and a dynamic assay range that have not been previously reported with any other assay methodologies. The assay has been automated in 96- and 384-well formats, providing assay data that are equivalent to, if not better than, data generated by hand. This report demonstrates the application of this novel assay technology to the functional analysis of a specific G protein-coupled receptor, neuropeptide receptor Y1, on SK-N-MC cells. Our data indicate the feasibility of utilizing this assay methodology for monitoring cAMP levels in a wide range of functional cell-based assays for high throughput screening.

scholarly journals Extensive crosstalk of G protein-coupled receptors with the Hedgehog signalling pathway

Development ◽  
2021 ◽  
pp. dev.189258
Author(s):  
Farah Saad ◽  
David R. Hipfner
Keyword(s):  
G Protein ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
G Protein Coupled Receptors ◽  
Signalling Pathway ◽  
Protein Activity ◽  
Cellular Sensitivity ◽  
Hedgehog Signalling Pathway ◽  
G Protein Coupled ◽  
Camp Levels

Hedgehog (Hh) ligands orchestrate tissue patterning and growth by acting as morphogens, dictating different cellular responses depending on ligand concentration. Cellular sensitivity to Hh ligands is influenced by heterotrimeric G protein activity, which controls production of the second messenger 3',5'-cyclic adenosine monophosphate (cAMP). cAMP in turn activates Protein kinase A (PKA), which functions as an inhibitor and (uniquely in Drosophila) an activator of Hh signalling. A few mammalian Gαi- and Gαs-coupled G protein-coupled receptors (GPCRs) have been shown to influence Sonic Hh (Shh) responses in this way. To determine if this is a more general phenomenon, we carried out an RNAi screen targeting GPCRs in Drosophila. RNAi-mediated depletion of more than 40% of GPCRs tested either decreased or increased Hh responsiveness in the developing Drosophila wing, closely matching the effects of Gαs and Gαi depletion, respectively. Genetic analysis indicated that the orphan GPCR Mthl5 lowers cAMP levels to attenuate Hh responsiveness. Our results identify Mthl5 as a new Hh signalling pathway modulator in Drosophila and suggest that many GPCRs may crosstalk with the Hh pathway in mammals.

Gα 16/z Chimeras Efficiently Link a Wide Range of G Protein— Coupled Receptors to Calcium Mobilization

2003 ◽  
Vol 8 (1) ◽  
pp. 39-49 ◽  
Author(s):  
Andrew M.F. Liu ◽  
Maurice K.C. Ho ◽  
Cecilia S.S. Wong ◽  
Jasmine H.P. Chan ◽  
Anson H.M. Pau ◽  
...  
Keyword(s):  
G Protein ◽  
G Proteins ◽  
G Protein Coupled Receptors ◽  
Imaging Plate ◽  
Response Curves ◽  
Gpcr Activation ◽  
Wide Range ◽  
Intracellular Ca ◽  
Screening Assays ◽  
G Protein Coupled

G protein—coupled receptors (GPCRs) represent a class of important therapeutic targets for drug discovery. The integration of GPCRs into contemporary high-throughput functional assays is critically dependent on the presence of appropriate G proteins. Given that different GPCRs can discriminate against distinct G proteins, a universal G protein adapter is extremely desirable. In this report, the authors evaluated two highly promiscuous Gα16/z chimeras, 16z25 and 16z44, for their ability to translate GPCR activation into Ca2+ mobilization using the fluorescence imaging plate reader (FLIPR) and aequorin. A panel of 24 Gs- or Gi-coupled receptors was examined for their functional association with the Gα16/z chimeras. Although most of the GPCRs tested were incapable of inducing Ca2+ mobilization upon their activation by specific agonists, the introduction of 16z25 or 16z44 allowed all of these GPCRs to mediate agonist-induced Ca 2+ mobilization. In contrast, only 16 of the GPCRs tested were capable of using Gα16 to mobilize intracellular Ca2+. Analysis of dose-response curves obtained with the δ-opioid, dopamine D1 , and Xenopus melatonin Mel1c receptors revealed that the Gα 16/z chimeras possess better sensitivity than Gα16 in both the FLIPR and aequorin assays. Collectively, these studies help to validate the promiscuity of the Gα16/z chimeras as well as their application in contemporary drug-screening assays that are based on ligand-induced Ca 2+ mobilization. ( Journal of Biomolecular Screening 2003:39-49)

Mapping the Heart

2010 ◽  
Vol 18 (4) ◽  
pp. 6-8
Author(s):  
Stephen W. Carmichael
Keyword(s):  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
G Protein Coupled Receptors ◽  
Receptor Subtypes ◽  
Cardiac Muscle Cells ◽  
Guanine Nucleotide Binding Protein ◽  
The Common ◽  
Guanine Nucleotide Binding ◽  
First Time ◽  
G Protein Coupled

Some of the receptors on the surface of cardiac muscle cells (cardiomyocytes) mediate the response of these cells to catecholamines by causing the production of the common second messenger cyclic adenosine monophosphate (cAMP). An example of such receptors are the β1- and β2-adrenergic receptors (βARs) that are heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors. Selective stimulation of these two receptor subtypes leads to distinct physiological and pathophysiological responses, but their precise location on the surface of cardiomyocytes has not been correlated with these responses. In an ingenious combination of techniques, Viacheslav Nikolaev, Alexey Moshkov, Alexander Lyon, Michele Miragoli, Pavel Novak, Helen Paur, Martin Lohse, Yuri Korchev, Sian Harding, and Julia Gorelik have mapped the function of these receptors for the first time.

scholarly journals Applications of molecular replacement to G protein-coupled receptors

2013 ◽  
Vol 69 (11) ◽  
pp. 2287-2292 ◽  
Author(s):  
Andrew C. Kruse ◽  
Aashish Manglik ◽  
Brian K. Kobilka ◽  
William I. Weis
Keyword(s):  
G Protein ◽  
Structural Biology ◽  
Structural Information ◽  
G Protein Coupled Receptors ◽  
Integral Membrane Proteins ◽  
Molecular Replacement ◽  
Gpcr Activation ◽  
Health And Disease ◽  
Almost All ◽  
G Protein Coupled

G protein-coupled receptors (GPCRs) are a large class of integral membrane proteins involved in regulating virtually every aspect of human physiology. Despite their profound importance in human health and disease, structural information regarding GPCRs has been extremely limited until recently. With the advent of a variety of new biochemical and crystallographic techniques, the structural biology of GPCRs has advanced rapidly, offering key molecular insights into GPCR activation and signal transduction. To date, almost all GPCR structures have been solved using molecular-replacement techniques. Here, the unique aspects of molecular replacement as applied to individual GPCRs and to signaling complexes of these important proteins are discussed.

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