The Tango GPCR Assay System (Figure 1) is a proprietary platform based upon ligand binding to a specific G protein-coupled receptor (GPCR) that triggers desensitization, a process mediated by the recruitment of protease-tagged arrestin proteins to the activated receptor. The protease-tagged arrestin cleaves a protease site fused to the C-terminus of the GPCR, releasing a non-native transcription factor.
This transcription factor immediately enters the nucleus, thus bypassing additional signaling intermediates. There, the transcription factor directly regulates transcription of a beta-lactamase reporter construct, which is measured upon addition of the live-cell substrate (Figure 2). The blue to green fluorescence ratio obtained directly correlates to receptor modulation by agonists or antagonists. Activation of the reporter gene provides a quantifiable measurement of the degree of interaction between the target receptor and the protease-tagged arrestin partner.
Tango GPCR assays have been validated for a diverse array of GPCRs, including receptors related to each of the major G protein pathways and activated by a variety of ligand types:
Quantitative measurements of the GPCR activation and arrestin recruitment can be accurately determined with the Tango GPCR Assay System. This method is ideal for high throughput screening (HTS) applications and is highly amenable to miniaturization. Tango GPCR cell lines can be used to monitor agonist-mediated receptor activation, to assess the relative efficacies of different compounds, and to measure receptor inactivation by specific antagonists (Figure 4). The readout is also specific to the target receptor (Figure 3).
Figure 3. Target selectivity. Tango GPCR cell lines and profiling service enable selective interrogation of your target receptor of interest. The vasopressin V2 receptor is expressed in HEK 293 cells and is assayed for activity using a calcium flux assay and a Tango assay. Normally, treatment of cells with vasopressin (a ligand for the target receptor), as well as carbachol and ATP (lgands for endogenous nontarget receptore in HEK 293 cells), results in indistinguishable signals in a calcium flux assay. In contrast, the Tango GPCR cell lines generate a signal only upon stimulation using the target receptor's cognate ligand.
Tango™ technology is available on a custom basis for client-directed targets. Engineered cell lines are provided as a validated master cell line stock. Cells can also be provided on-demand in either 1-10 plate/vial configurations in either a dividing or division arrested format.
For Research Use Only. Not for use in diagnostic procedures.