The PathHunter OPRK1 Total Internalization cell line is a stable, engineered cell line for use in studying drug candidates (small molecules or biologics) affecting GPCR activation and internalization. This cell line uses EFC technology to measure ligand-induced internalization of OPRK1 via detection of localization to the early endosome. The included cell line overexpresses EA-tagged OPRK1 and a ProLink-tagged early endosome protein. Upon ligand-induced receptor activation, resulting internalization of the OPRK1 receptor to the early endosome leads to production of EFC signal. This stable modified cell line is provided as two vials of cryopreserved cells. For detailed product information, User Manual and datasheet, visit www.discoverx.com/gpcr.