The PathHunter® assay monitors the interaction of two proteins in a whole cell, homogeneous assay format using enzyme fragment complementation. In this system, a small 42 AA enzyme fragment, ProLabel is appended to the protein of interest. The larger enzyme fragment EA (Enzyme Acceptor) resides in the kit. Activation of the pathway results in protein degradation, which can be detected using the PathHunter® ProLabel and ProLink Detection Kit (93-0812). The signal can be read on any standard luminometer.