Leveraging the principle that virtually all GPCRs rapidly undergo deactivation or "desensitization" by a common pathway, the Transfluor® Assay is a cell-based fluorescence assay used to screen for G-protein coupled receptor (GPCR) ligands and other potential drugs that regulate GPCRs. By attaching a fluorescent label to beta-arrestin, the location of the receptor-arrestin complex may be monitored during receptor activation. Since desensitization only occurs with an activated receptor, monitoring beta-arrestin translocation and subsequent receptor recycling provides a method to detect the activation of any GPCR. 
 
Studying of this mechanism enables researchers to identify the impact of GPCR ligands on a variety of physiological processes including behavior, mood, inflammation, nervous system, and olfactory responses. In addition, researchers can gain insight into the complexities of receptor degradation and recycling for a given target.