Recombinant human EPHA4 (610-887) was expressed by baculovirus in Sf9 insect cells using an N-terminal GST tag. EPHA4 also known as EPH receptor A4, belongs to the ephrin receptor subfamily of protein-tyrosine kinases which have been implicated in mediating developmental events, particularly in the nervous system. The EPHA4 ligand ephrin-A3 is localized to the astrocytic processes that envelop the spine. Activation of EPHA4 by ephrin-A3 induces spinal retraction and reduces spine density and inhibits the interaction leading to distorted spine shape and organization. ADP-Glo Kinase Assay is a luminescent kinase assay that measures ADP formed from a kinase reaction; ADP is converted into ATP, which is a substrate in a reaction catalyzed by Ultra-Glo Luciferase that produces light. The luminescent signal positively correlates with ADP amount and kinase activity. The assay is well suited for measuring the effects chemical compounds have on the activity of a broad range of purified kinases, making it ideal for both primary screening as well as kinase selectivity profiling. The ADP-Glo Kinase Assay can be used to monitor the activity of virtually any ADP-generating enzyme (e.g., kinase or ATPase) using up to 1mM ATP.