β-Arrestin Functional Assay Services

β-arrestins are commonly expressed in all cell types and play a role in G-protein-coupled receptors (GPCRs) desensitization, control of GPCR intracellular transport, and activation of GPCRs into a variety of signaling pathways. Therefore, β-arrestin-mediated signaling constitutes an important part of GPCR signaling in addition to G protein-mediated signaling. Creative Biolabs is a multidisciplinary, qualified & experienced team. We can apply our considerable experience with a β-arrestin assay to develop the necessary analytics specific to your project.

Overview of β-arrestin Recruitment Assay

β-arrestins are cytosolic proteins that bind to ligand-activated GPCRs, uncouple the receptors from G proteins, and target the receptors to clathrin-coated endocytic vesicles. β-arrestins are critical regulators and transducer proteins for G protein-coupled receptors (GPCRs). β-arrestins are cytoplasmic proteins that bind ligand-activated GPCRs, uncouple receptors from G proteins, and target receptors to clathrin-coated endocytic vesicles. β-arrestins are key regulators and transducer proteins of GPCRs. G protein and β-arrestin pathways are distinct and can be pharmacologically regulated independently by "biased ligands". Therefore, β-arrestin based assays are more interesting, potentially providing new insights into the functional selectivity (biased agonism) of GPCR signaling. The β-arrestin recruitment assay provides a new, universal, and G-protein independent method for GPCR screening and drug discovery. Such assays are particularly useful for the screening of Gα_i-coupled GPCRs, which traditionally suffer from a small assay window in second messenger detection systems, and orphan GPCRs.

Fig.1 The GPCR β-arrestin recruitment assay principle. (Wang, 2017)

Advantages of β-arrestin Recruitment Assay

The first commercialized β-arrestin recruitment assay is performed using GFP-tagged β-arrestin. The benefits of this assay include the following:

• No fluorescent dyes or secondary substrates are needed;
• Visualization of β-arrestin localization;
• The cell imaging assay allows parallel detection of putative compound liabilities;
• Multiplexing with the receptor internalization assay and providing additional information regarding drug effect for ligand-induced trafficking.

Flowchart of Assay Development Guidelines

1. Select a GPCR target cell line and a control cell line expression of another GPCR, preferably with a similar total and background.
2. Determine agonist dose-response relationships and potency values while optimizing cell density and determining the time course and desired temperature of β-arrestin recruitment.
3. Determine antagonist dose-response relationships and IC₅₀ values by stimulating with EC_50-80 agonist concentration.
4. Assess assay performance statistics, including Z’, signal-to-background ratio, and reproducibility of potency data.

The β-arrestin recruitment assay has added an important piece to the repertoire of assay tools in drug discovery. Creative Biolabs uses our state-of-the-art R&D expertise to help our customers develop stand-out products that offer true value to consumers. We pride ourselves on being an innovator and problem solver in GPCRs. Please feel free to contact us for more about the β-arrestin recruitment assay.

Reference

1. Wang, T.; et al. Measurement of β-Arrestin Recruitment for GPCR Targets. Assay Guidance Manual. 2017.