Epha4, as known as ephrin type-A receptor 4, is a single-pass type 1 membrane protein which belongs to the protein kinase superfamily and ephrin receptor subfamily. This protein may play a role in a signal transduction process involved in hindbrain pattern formation. The ephrins and ephrin receptors comprise the largest subfamily of receptor protein-tyrosine kinases and have been implicated in mediating developmental events, especially in the nervous system and in erythropoiesis. Recombinant mouse Epha4, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques