scholarly journals DCyFIR: a high-throughput CRISPR platform for multiplexed G protein-coupled receptor profiling and ligand discovery

2020 ◽  
Author(s):  
NJ Kapolka ◽  
GJ Taghon ◽  
JB Rowe ◽  
WM Morgan ◽  
JF Enten ◽  
...  
Keyword(s):  
G Protein ◽  
High Throughput ◽  
G Protein Coupled Receptors ◽  
Membrane Receptors ◽  
Yeast Genome ◽  
Innovative Technology ◽  
Ligand Discovery ◽  
Ligand Interactions ◽  
Approved Drugs ◽  
G Protein Coupled

AbstractMore than 800 G protein-coupled receptors (GPCRs) comprise the largest class of membrane receptors in humans. While there is ample biological understanding and many approved drugs for prototypic GPCRs, most GPCRs still lack well-defined biological ligands and drugs. Here, we report our efforts to tap the potential of understudied GPCRs by developing yeast-based technologies for high-throughput CRISPR engineering and GPCR ligand discovery. We refer to these technologies collectively as Dynamic Cyan induction by Functional Integrated Receptors: DCyFIR. A major advantage of DCyFIR is that GPCRs and other assay components are CRISPR-integrated directly into the yeast genome, making it possible to decode ligand specificity by profiling mixtures of GPCR-barcoded yeast strains in a single tube. To demonstrate the capabilities of DCyFIR, we engineered a yeast strain library of 30 human GPCRs and their 300 possible GPCR-Gα coupling combinations. Profiling of these 300 strains, using parallel (DCyFIRscreen) and multiplex (DCyFIRplex) DCyFIR modes, recapitulated known GPCR agonism with 100% accuracy, and identified unexpected interactions for the receptors ADRA2B, HCAR3, MTNR1A, S1PR1, and S1PR2. To demonstrate DCyFIR scalability, we profiled a library of 320 human metabolites and observed new GPCR-ligand interactions with amino acid, lipid, sugar, and steroid metabolites. Remarkably, many of these findings pertained to understudied “pharmacologically dark” receptors GPR4, GPR65, GPR68, and HCAR3. For example, we found that kynurenic acid activated HCAR3 with a nearly 20-fold lower EC50 than GPR35, its known receptor. Taken together, these findings demonstrate the power of DCyFIR for identifying novel ligand interactions with prototypic and understudied GPCRs.Significance StatementG protein-coupled receptors (GPCRs) are the largest class of membrane receptors in humans. As such, GPCR signaling is central to human biology and medicine. While more than 30% of approved drugs target roughly 150 GPCRs, most receptors lack well-defined endogenous ligands and are currently not druggable. To address this challenge, we created a GPCR screening platform for ligand and drug discovery. This innovative technology enables the cost-effective profiling of ligands and drug compounds against mixtures of hundreds of GPCR-barcoded cell strains in a single experiment. Because a ligand or drug is tested against a collection of receptors all at once, our novel method accelerates the process of identifying potential GPCR ligands and drugs.

scholarly journals DCyFIR: a high-throughput CRISPR platform for multiplexed G protein-coupled receptor profiling and ligand discovery

2020 ◽  
Vol 117 (23) ◽  
pp. 13117-13126
Author(s):  
N. J. Kapolka ◽  
G. J. Taghon ◽  
J. B. Rowe ◽  
W. M. Morgan ◽  
J. F. Enten ◽  
...  
Keyword(s):  
G Protein ◽  
High Throughput ◽  
Mammalian Cells ◽  
Membrane Receptors ◽  
Yeast Genome ◽  
Ligand Specificity ◽  
Ligand Discovery ◽  
Ligand Interactions ◽  
Approved Drugs ◽  
G Protein Coupled

More than 800 G protein-coupled receptors (GPCRs) comprise the largest class of membrane receptors in humans. While there is ample biological understanding and many approved drugs for prototypic GPCRs, most GPCRs still lack well-defined biological ligands and drugs. Here, we report our efforts to tap the potential of understudied GPCRs by developing yeast-based technologies for high-throughput clustered regularly interspaced short palindromic repeats (CRISPR) engineering and GPCR ligand discovery. We refer to these technologies collectively as Dynamic Cyan Induction by Functional Integrated Receptors, or DCyFIR. A major advantage of DCyFIR is that GPCRs and other assay components are CRISPR-integrated directly into the yeast genome, making it possible to decode ligand specificity by profiling mixtures of GPCR-barcoded yeast strains in a single tube. To demonstrate the capabilities of DCyFIR, we engineered a yeast strain library of 30 human GPCRs and their 300 possible GPCR–Gα coupling combinations. Profiling of these 300 strains, using parallel (DCyFIRscreen) and multiplex (DCyFIRplex) DCyFIR modes, recapitulated known GPCR agonism with 100% accuracy, and identified unexpected interactions for the receptors ADRA2B, HCAR3, MTNR1A, S1PR1, and S1PR2. To demonstrate DCyFIR scalability, we profiled a library of 320 human metabolites and discovered several GPCR–metabolite interactions. Remarkably, many of these findings pertained to understudied pharmacologically dark receptors GPR4, GPR65, GPR68, and HCAR3. Experiments on select receptors in mammalian cells confirmed our yeast-based observations, including our discovery that kynurenic acid activates HCAR3 in addition to GPR35, its known receptor. Taken together, these findings demonstrate the power of DCyFIR for identifying ligand interactions with prototypic and understudied GPCRs.

scholarly journals Imaging of persistent cAMP signaling by internalized G protein-coupled receptors

2010 ◽  
Vol 45 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Davide Calebiro ◽  
Viacheslav O Nikolaev ◽  
Martin J Lohse
Keyword(s):  
G Protein ◽  
Intracellular Signaling ◽  
Current Model ◽  
Living Cells ◽  
G Protein Coupled Receptors ◽  
Membrane Receptors ◽  
Optical Methods ◽  
Camp Signaling ◽  
Gpcr Signaling ◽  
G Protein Coupled

G protein-coupled receptors (GPCRs) are the largest family of plasma membrane receptors. They mediate the effects of several endogenous cues and serve as important pharmacological targets. Although many biochemical events involved in GPCR signaling have been characterized in great detail, little is known about their spatiotemporal dynamics in living cells. The recent advent of optical methods based on fluorescent resonance energy transfer allows, for the first time, to directly monitor GPCR signaling in living cells. Utilizing these methods, it has been recently possible to show that the receptors for two protein/peptide hormones, the TSH and the parathyroid hormone, continue signaling to cAMP after their internalization into endosomes. This type of intracellular signaling is persistent and apparently triggers specific cellular outcomes. Here, we review these recent data and explain the optical methods used for such studies. Based on these findings, we propose a revision of the current model of the GPCR–cAMP signaling pathway to accommodate receptor signaling at endosomes.

scholarly journals Misfolded G Protein-Coupled Receptors and Endocrine Disease. Molecular Mechanisms and Therapeutic Prospects

2021 ◽  
Vol 22 (22) ◽  
pp. 12329
Author(s):  
Alfredo Ulloa-Aguirre ◽  
Teresa Zariñán ◽  
Eduardo Jardón-Valadez
Keyword(s):  
Plasma Membrane ◽  
G Protein ◽  
Intracellular Signaling ◽  
Molecular Mechanisms ◽  
G Protein Coupled Receptors ◽  
Membrane Receptors ◽  
Therapeutic Interventions ◽  
Endocrine Function ◽  
Receptor Protein ◽  
G Protein Coupled

Misfolding of G protein-coupled receptors (GPCRs) caused by mutations frequently leads to disease due to intracellular trapping of the conformationally abnormal receptor. Several endocrine diseases due to inactivating mutations in GPCRs have been described, including X-linked nephrogenic diabetes insipidus, thyroid disorders, familial hypocalciuric hypercalcemia, obesity, familial glucocorticoid deficiency [melanocortin-2 receptor, MC2R (also known as adrenocorticotropin receptor, ACTHR), and reproductive disorders. In these mutant receptors, misfolding leads to endoplasmic reticulum retention, increased intracellular degradation, and deficient trafficking of the abnormal receptor to the cell surface plasma membrane, causing inability of the receptor to interact with agonists and trigger intracellular signaling. In this review, we discuss the mechanisms whereby mutations in GPCRs involved in endocrine function in humans lead to misfolding, decreased plasma membrane expression of the receptor protein, and loss-of-function diseases, and also describe several experimental approaches employed to rescue trafficking and function of the misfolded receptors. Special attention is given to misfolded GPCRs that regulate reproductive function, given the key role played by these particular membrane receptors in sexual development and fertility, and recent reports on promising therapeutic interventions targeting trafficking of these defective proteins to rescue completely or partially their normal function.

Intracrine signaling through lipid mediators and their cognate nuclear G-protein-coupled receptors: a paradigm based on PGE2, PAF, and LPA1 receptorsThis paper is one of a selection of papers published in this Special Issue, entitled The Nucleus: A Cell Within A Cell.

2006 ◽  
Vol 84 (3-4) ◽  
pp. 377-391 ◽  
Author(s):  
Tang Zhu ◽  
Fernand Gobeil ◽  
Alejandro Vazquez-Tello ◽  
Martin Leduc ◽  
Lenka Rihakova ◽  
...  
Keyword(s):  
G Protein ◽  
Nuclear Localization ◽  
Platelet Activating Factor ◽  
Rat Hepatocytes ◽  
Lipid Mediators ◽  
G Protein Coupled Receptors ◽  
Membrane Receptors ◽  
Surface Receptors ◽  
A Cell ◽  
G Protein Coupled

Prostaglandins (PGs), platelet-activating factor (PAF), and lysophosphatidic acid (LPA) are ubiquitous lipid mediators that play important roles in inflammation, cardiovascular homeostasis, and immunity and are also known to modulate gene expression of specific pro-inflammatory genes. The mechanism of action of these lipids is thought to be primarily dependent on their specific plasma membrane receptors belonging to the superfamily of G-protein-coupled receptors (GPCR). Increasing evidence suggests the existence of a functional intracellular GPCR population. It has been proposed that immediate effects are mediated via cell surface receptors whereas long-term responses are dependent upon intracellular receptor effects. Indeed, receptors for PAF, LPA, and PGE2 (specifically EP1, EP3, and EP4) localize at the cell nucleus of cerebral microvascular endothelial cells of newborn pigs, rat hepatocytes, and cells overexpressing each receptor. Stimulation of isolated nuclei with these lipids reveals biological functions including transcriptional regulation of major genes, namely c-fos, cylooxygenase-2, and endothelial as well as inducible nitric oxide synthase. In the present review, we shall focus on the nuclear localization and signaling of GPCRs recognizing PGE2, PAF, and LPA phospholipids as ligands. Mechanisms on how nuclear PGE2, PAF, and LPA receptors activate gene transcription and nuclear localization pathways are presented. Intracrine signaling for lipid mediators uncover novel pathways to elicit their effects; accordingly, intracellular GPCRs constitute a distinctive mode of action for gene regulation.

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)

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