Tango™ GPR44-bla U2OS cells contain the human G protein coupled receptor 44 (GPR44) linked to a TEV protease site and a Gal4-VP16 transcription factor stably integrated into the Tango™ GPCR-bla U2OS parental cell line. This parental cell line stably expresses a beta-arrestin⁄TEV protease fusion protein and the beta-lactamase reporter gene under the control of a UAS response element. The Tango™ GPR44-bla U2OS cells have been functionally validated for Z’ factor and EC50 concentrations of Indomethacin. In addition, Tango™ GPR44-bla U2OS cells have been tested for assay performance under variable conditions.