The PathHunter CXCR7 Activated GPCR internalization eXpress kit provides an easy to-use cell based assay to study drug candidates (small molecules or biologics) affecting GPCR activation and internalization. This kit uses EFC technology to measure ligand-induced internalization of CXCR7 via detection of localization to the early endosome. The included cell line overexpresses EA-tagged β-Arrestin-2 as well as a ProLink-tagged early endosome protein and untagged CXCR7. Upon ligand-induced receptor activation, β-Arrestin-2 is recruited to the activated GPCR and the resulting CXCR7-arrestin complex is internalized to the early endosome, leading to production of EFC signal. eXpress kits are a convenient, ready-to-use format which contains all materials needed to run the assay, including single-use vials of cryopreserved cells, cell plating media, detection reagent, and assay plates. For detailed product information, User Manual and Datasheet, visit www.discoverx.com/express.