• Purity

  >95%, by SDS-PAGE under reducing conditions and visualized by silver stain

• Endotoxin Level

  <0.10 EU per 1 μg of the protein by the LAL method.  

• Activity

  Measured by its binding ability in a functional ELISA.

  When Recombinant Human (rh) EphA3 Fc Chimera is coated at 2 μg/mL (100 μL/well), the concentration of biotinylayed rhEphrin A5 Fc Chimera that produces 50% of the optimal binding response is found to be approximately 5 ‑ 25 ng/mL.

• Source

  Mouse myeloma cell line, NS0-derived

  Human EphA3 (Met1 - Gln541) Accession # NP_005224	IEGRMD	Human IgG1 (Pro100 - Lys330)
  N-terminus		C-terminus

• Accession #

• N-terminal Sequence    
  Analysis

  Glu21

• Structure / Form

  Disulfide-linked homodimer    
   

• Predicted Molecular Mass

  85.4 kDa (monomer)

• SDS-PAGE

  100-110 kDa, reducing conditions

Background: EphA3

EphA3, also known as Cek4, Mek4, Hek, Tyro4, and Hek4, is a 135 kDa glycosylated member of the transmembrane Eph receptor tyrosine kinase family. The A and B classes of Eph proteins are distinguished by Ephrin ligand binding preference but have a common structural organization. EphA3 preferentially binds to Ephrin-A5. Eph-Ephrin interactions are widely involved in the regulation of cell migration, tissue morphogenesis, and cancer progression (1, 2). The 521 amino acid (aa) extracellular domain (ECD) of human EphA3 contains an N-terminal Ephrin binding region, a cysteine-rich region, and two fibronectin type II domains. The 418 aa cytoplasmic domain contains the tyrosine kinase domain and a sterile alpha motif (SAM) (3, 4). Within the ECD, human EphA3 shares 96% aa sequence identity with mouse and rat EphA3. Alternate splicing generates a secreted isoform that consists of nearly the entire ECD. EphA3 is expressed in the developing forebrain, retinal axons, some spinal cord motor neurons, and the heart where it plays an important role in axonal repulsion and organ morphogenesis (5 - 8). It is upregulated on some hematopoietic and solid tumor cells and on astrocytes surrounding injured nervous tissue (3, 5, 9 - 11). EphA3 ligation inhibits cellular adhesion to fibronectin as well as cellular migration (9, 10). Transmembrane EphA3 associates   in cis with ADAM10 which then promotes the cleavage   in trans of Ephrin-A5 (12). It also associates   in cis with Ephrin-A5 on retinal axons, thereby preventing the activation of EphA3 by Ephrin-A (13). Multiple tyrosine residues within the cytoplasmic region of EphA3 become phosphorylated during ligand-induced signaling (14, 15).

• References:

1. Pasquale, E.B. (2005) Nat. Rev. Mol. Cell Biol. 6:462.

2. Merlos-Suarez, A. and E. Batlle (2008) Curr. Opin. Cell Biol. 20:194.

3. Wicks, I.P. et al. (1992) Proc. Natl. Acad. Sci. 89:1611.

4. Lackmann, M. et al. (1998) J. Biol. Chem. 273:20228.

5. Chiari, R. et al. (2000) Cancer Res. 60:4855.

6. Kudo, C. et al. (2005) J. Comp. Neurol. 487:255.

7. Kilpatrick, T.J. et al. (1996) Mol. Cell. Neurosci. 7:62.

8. Stephen, L.J. et al. (2007) Dev. Biol. 302:66.

9. Smith, L.M. et al. (2004) Exp. Cell Res. 292:295.

10. Clifford, N. et al. (2008) J. Cell. Biochem. 105:1250.

11. Irizarry-Ramirez, M. et al. (2005) J. Neurotrauma 22:929.

12. Janes, P.W. et al. (2005) Cell 123:291.

13. Carvalho, R.F. et al. (2006) Nat. Neurosci. 9:322.

14. Shi, G. et al. (2010) Cell Res. June epub.

15. Hu, T. et al. (2009) Biochemistry 48:6369.

• Long Name:

  Eph Receptor A3

• Entrez Gene IDs:

  2042 (Human); 13837 (Mouse)

• Alternate Names:

  Cek4; EC 2.7.10; EC 2.7.10.1; EK4; EPH receptor A3; EphA3; EPH-like kinase 4; ephrin type-A receptor 3; ETK; Hek4; HEKETK1eph-like tyrosine kinase 1; human embryo kinase 1; TYRO4 protein tyrosine kinase; Tyro4; Tyrosine-protein kinase receptor ETK1; Tyrosine-protein kinase TYRO4