A β-Lactamase Reporter Assay for Monitoring the Activation of the Smoothened Pathway

The seven-transmembrane protein Smoothened (Smo) mediates the cellular response to the Hedgehog protein signal and is involved in cell growth and differentiation during embryonic development. Stimulation of the Smo pathway is directly implicated in tissue maintenance and repair, but overactivation of Smo could lead to tumorigenesis. We developed a robust and sensitive functional cell-based assay that measures the activity of endogenous Smo using a β-lactamase transcriptional readout. This is the first Smo reporter assay that utilizes β-lactamase reporter technology. This assay type has distinct advantages over other reporter technologies and can be used in a high-throughput mode to search for therapeutically relevant downstream Smo target effectors.