The PathHunter Signaling Pathway Reporter Assays are stable clonal cell lines that monitor the activation of specific signaling pathways, utilizing the established PathHunter Enzyme Fragment Complementation (EFC) technology. Each stable cell line is engineered to express a synthetic DNA reporter construct, comprising a pathway-specific transcription factor response element that drives expression of ePL-tagged reporter protein. The activated signaling pathway induces expression of the ePL-tagged reporter protein, which is measured by addition of the detection reagent containing EA, resulting in complementation of the two enzyme fragments, and production of an active enzyme that hydrolyzes the substrate to generate a chemiluminescent signal.