GPCR Assays and Functional Signaling Profiling Services

CD Biosynsis offers comprehensive G Protein-Coupled Receptor (GPCR) Assays, essential for drug discovery targeting the largest family of membrane receptors, responsible for mediating the majority of cellular responses to hormones, neurotransmitters, and sensory stimuli. GPCRs are the targets of approximately one-third of all marketed drugs. Our platform provides quantitative measurement of ligand binding, functional agonism, inverse agonism, and antagonism, covering all major G-protein coupling classes (Gs, Gi, Gq). We utilize state-of-the-art technologies, including high-throughput FLIPR (Ca2+ flux), cAMP assays (HTRF/AlphaScreen), label-free technologies (DMPK), and BRET/LRET for arrestin recruitment and internalization. Researchers can select and combine specific GPCR targets and signaling assays to build a custom profiling panel, enabling precise characterization of compound efficacy and signaling bias.

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Multiparametric Analysis of Receptor Function and Bias

The complexity of GPCRs lies in their ability to couple to multiple G proteins and recruit G protein-independent effectors (e.g., arrestins), a phenomenon known as biased agonism. Accurate drug profiling requires measuring multiple downstream signals to fully characterize a ligand's functional profile. Our services provide selectable assay modules, allowing clients to combine primary G-protein signaling (cAMP, Ca2+) with secondary readouts (arrestin, internalization). This integrated approach enables the differentiation of balanced agonists from biased agonists, which is critical for developing next-generation therapeutics with improved efficacy and reduced side effects. We offer validated, stable cell lines expressing hundreds of human GPCR targets across all major G-protein classes.

Customizable GPCR Target and Functional Profiling

G-Protein Signaling Pathways Receptor Families and Subtypes Functional and Mechanistic Modules

Core G-Protein Signaling Pathways

Choose Primary Signaling Readouts for Compound Screening

Check the box next to the G-Protein Pathway readout you wish to include in your customized assay panel:

Gs Pathway (cAMP Accumulation)

Gi Pathway (cAMP Inhibition/Adenylyl Cyclase)

Gq Pathway (Intracellular Ca2+ Flux)

G12/13 Pathway (RhoA Activation)

cAMP Kinetics and Concentration

IP-1 Production (IP3 Pathway Surrogate)

Reporter Gene Assays (SRF, NFAT, CRE)

Label-Free Cell Adhesion/Migration

Selectable Receptor Families and Subtypes

Choose Specific GPCR Targets for Screening

Select the GPCR targets required for activity, binding, and selectivity testing:

Adrenergic Receptors (e.g., Beta-2, Alpha-1)

Opioid Receptors (e.g., Mu, Kappa, Delta)

Chemokine Receptors (e.g., CXCR4, CCR5)

Histamine Receptors (e.g., H1, H4)

Serotonin Receptors (5-HT Subtypes)

Purinergic Receptors (e.g., P2Y, Adenosine)

Orphan GPCRs (Custom Screening)

Full GPCR Target Library (400+ Targets)

Functional and Mechanistic Modules

Select Advanced Signaling and Binding Services

Arrestin Recruitment (Biased Agonism)

BRET/LRET-based measurement of Beta-Arrestin recruitment, crucial for analyzing signaling bias.

Receptor Internalization/Trafficking

High-Content Imaging (HCI) to quantify receptor movement from the cell surface to endosomes.

Radioligand Binding Affinity (Ki)

Precise determination of ligand binding constant (Ki, Kd) using filtration assays (e.g., 3H-labeled ligands).

GPCR Functional Assay Workflow

A multi-stage process for characterizing ligand activity and bias.

Target Selection and Cell Line Validation

Primary Signaling (Agonism/Antagonism)

Secondary Signaling and Bias Analysis

Binding, Kinetics, and Reporting

Receptor Selection: Finalize the list of target GPCRs and select the appropriate stably expressing cell lines.

Baseline QC: Validate basal and maximal stimulation responses (Z-factor) for all chosen signaling pathways (Gs, Gi, Gq).

G-Protein Profiling: Screen compounds for agonism and antagonism using cAMP (HTRF/AlphaScreen) and Ca2+ flux (FLIPR) assays.

EC50/IC50 Determination: Calculate the functional potency of leads for each G-protein pathway.

Arrestin Assays: Measure Beta-Arrestin recruitment (BRET/LRET) to determine the compound's recruitment potency and efficacy.

Internalization: Quantify receptor endocytosis via High-Content Imaging or ELISA (if selected).

  • Binding Affinity: Determine the non-functional binding constant (Ki) via competition radioligand binding assays.
  • Bias Calculation: Quantify signaling bias by comparing functional potencies (EC50) of G-protein vs. Arrestin pathways.
  • Reporting: Deliver full dose-response curves, raw data, EC50/IC50/Ki values, and calculated bias factors.

Leading Technology for Complex GPCR Targets

Biased Agonism Analysis

           

Quantitative comparison of G-protein signaling vs. Arrestin recruitment using BRET/LRET technology.

High-Throughput Signaling

           

Integration of HTRF, AlphaScreen, and FLIPR for rapid, reliable screening of Gs, Gi, and Gq pathways.

Extensive Target Library

           

Access to hundreds of validated human GPCR subtypes, including many difficult-to-express Orphan receptors.

Radioligand Binding

           

Gold standard method for determining true thermodynamic binding affinity (Ki, Kd) independent of cellular function.

Client Testimonials on GPCR Assays

"The multiplexed Gs/Arrestin BRET assay clearly demonstrated our compound was a biased agonist, enabling us to advance a lead with a superior therapeutic profile."

Dr. Samuel Liu, Receptor Pharmacology Director

"The rapid FLIPR assay for Gq-coupled targets provided immediate, high-quality EC50 data, significantly speeding up our lead optimization cycle."

Ms. Clara Davis, Cardiovascular Drug Discovery

"The combination of functional assays and radioligand binding gave us the full picture—both potency (EC50) and true affinity (Ki)—necessary for IND-enabling studies."

Mr. Julian Chen, Preclinical Program Manager

FAQs about GPCR Assays

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What are the three main G-protein signaling pathways?

The three main signaling pathways are: Gs (stimulates adenylyl cyclase, increasing cAMP), Gi (inhibits adenylyl cyclase, decreasing cAMP), and Gq (activates Phospholipase C, increasing IP3 and Ca2+).

What is 'biased agonism' in GPCR signaling?

Biased agonism occurs when a ligand preferentially activates one signaling pathway (e.g., G-protein) over another (e.g., Beta-Arrestin recruitment) compared to the natural ligand. This can lead to selective therapeutic effects.

What is the difference between EC50 and Ki?

EC50 (Effective Concentration 50 percent) measures functional potency (the concentration required to elicit 50 percent maximal response). Ki (Inhibition Constant) measures true thermodynamic binding affinity to the receptor, regardless of function.

Why are BRET/LRET assays used for arrestin recruitment?

BRET (Bioluminescence Resonance Energy Transfer) and LRET (Luminescence Resonance Energy Transfer) are proximity assays that allow real-time, quantitative detection of the molecular interaction between the activated receptor and the Beta-Arrestin protein.

How much does Metabolic Engineering services cost?

The cost of Metabolic Engineering services depends on the project scope, complexity of the target compound, the host organism chosen, and the required yield optimization. We provide customized quotes after a detailed discussion of your specific research objectives.

Do your engineered strains meet regulatory standards?

We adhere to high quality control standards in all strain construction and optimization processes. While we do not handle final regulatory approval, our detailed documentation and compliance with best laboratory practices ensure your engineered strains are prepared for necessary regulatory filings (e.g., GRAS, FDA).

What to look for when selecting the best gene editing service?

We provide various gene editing services such as CRISPR-sgRNA library generation, stable transformation cell line generation, gene knockout cell line generation, and gene point mutation cell line generation. Users are free to select the type of service that suits their research.

Does gene editing allow customisability?

Yes, we offer very customised gene editing solutions such as AAV vector capsid directed evolution, mRNA vector gene delivery, library creation, promoter evolution and screening, etc.

What is the process for keeping data private and confidential?

We adhere to the data privacy policy completely, and all customer data and experimental data are kept confidential.

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