EphA8, Fc Chimera, Recombinant, Human, CF (Ephrin Type-A Receptor 8, Tyrosine-protein Kinase Receptor EEK, EPH- and ELK-related Kinase, EPH-like Kinase 3, EK3, hEK3, EEK, KIAA1459)

EphA8, also known as Hek3 and Eek, is a 120kD glycosylated member of the Eph family of transmembrane receptor tyrosine kinases. The A and B classes of Eph proteins are distinguished by Ephrin ligand binding preference but have a common structural organization. EphA4 binds and is activated by class A Ephrins but not class B Ephrins. Eph-Ephrin interactions are widely involved in the regulation of cell migration, tissue morphogenesis, and cancer progression. The 512aa extracellular domain (ECD) of human EphA8 contains an N-terminal Ephrin binding region, a cysteine rich region, and two fibronectin type III domains (FnIII). The 442aa cytoplasmic domain contains the tyrosine kinase domain and a sterile alpha motif (SAM). Within the ECD, human EphA8 shares 97% aa sequence identity with mouse and rat EphA8. EphA8 is expressed in neurons in the mesencephalon of the developing brain, particularly in the rostral tectum and the superior colliculus. It is enriched at the tips of neurite processes and plays a role in projection of superior colliculus axons through the posterior commissure. Its expression enhances neurite extension by means of a mechanism that does not require catalytic activity of the tyrosine kinase domain. Ephrin-mediated activation of the EphA8 kinase induces phosphorylation of tyrosine residues in the cytoplasmic domain, leading to association with signaling and scaffolding proteins and inhibition of cell-cell adhesion. Ligand binding can also promote the Integrin mediated cellular adhesion to Fibronectin. This function, like the enhancement of neurite extension, does not require activation of the kinase domain. Source: Recombinant corresponding to aa31-542 from human EphA8 expressed in CHO cells. Molecular Weight: ~83.2kD Biological Activity: Measured by its binding ability in a functional ELISA. When recombinant human EphA8 Fc Chimera is coated at 2ug/ml (100ul/well), the concentration of biotinylayed recombinant human EphrinA5 Fc Chimera that produces 50% of the optimal binding response is typically 2-12ng/ml. Endotoxin: ~1EU/1ug (LAL) Storage and Stability: Aliquot to avoid repeated freezing and thawing and store at -70 degrees C. Aliquots are stable for 3 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.