• Purity

  >95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining

• Endotoxin Level

  <0.01 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) EphA2 (Catalog # 3035-A2) is coated at 2 μg/mL (100 μL/well), the concentration of rhEphrin-A1 Fc Chimera that produces 50% of the optimal binding response is found to be approximately 0.6-3 ng/mL.

• Source

  Mouse myeloma cell line, NS0-derived

  Human Ephrin-A1 (Met1-Ser182) Accession # P20827	IEGRMD	Human IgG1 (Pro100-Lys330)
  N-terminus		C-terminus

• Accession #

• N-terminal Sequence    
  Analysis

  Asp19

• Predicted Molecular Mass

  46 kDa (monomer)

• SDS-PAGE

  55-60 kDa, reducing conditions

Background: Ephrin-A1

Ephrin-A1, also known as B61 and LERK-1, is a member of the Ephrin-A family of GPI-anchored ligands that bind and induce the tyrosine autophosphorylation of Eph receptors. Ephrin-A ligands are structurally related to the extracellular domains of the transmembrane Ephrin-B ligands. Eph-Ephrin interactions are widely involved in the regulation of cell migration, tissue morphogenesis, and cancer progression (1, 2). Human Ephrin-A1 is synthesized with an 18 amino acid (aa) signal peptide, a 164 aa mature chain, and a 23 aa C‑terminal propeptide which is removed prior to GPI linkage of Ephrin-A1 to the membrane (3, 4). It can also be released as a soluble molecule (3, 5, 6). The mature 21 ‑ 25 kDa human Ephrin-A1 shares 85% aa sequence identity with mouse and rat Ephrin-A1. Alternate splicing generates an additional isoform that lacks 22 aa in the juxtamembrane region (7).
This short isoform is also expressed on the cell surface and exhibits weakened binding to EphA2 (7). Ephrin-A1 is widely expressed on endothelial and epithelial cells, particularly in the lung, intestine, liver, and skin (4, 8). It is expressed on resting CD4⁺ T cells but is down‑regulated following activation (9, 10). Ligation of Ephrin-A1 on CD4⁺ T cells inhibits cell proliferation and activation, although soluble Ephrin-A1 can promote T cell chemotaxis (9, 10). In cancer, Ephrin-A1 is expressed by tumor cells as well as on the tumor‑associated vasculature (5, 6, 11). It inhibits tumor cell proliferation and migration but also supports tumor growth by promoting angiogenesis (12 ‑ 14). Soluble Ephrin-A1 additionally promotes neuronal survival and neurite extension (15).

• References:

1. Miao, H. and B. Wang (2009) Int. J. Biochem. Cell Biol. 41:762.

2. Pasquale, E.B. (2010) Nat. Rev. Cancer 10:165.

3. Holzman, L.B. et al. (1990) Mol. Cell. Biol. 10:5830.

4. Shao, H. et al. (1995) J. Biol. Chem. 270:5636.

5. Easty, D.J. et al. (1995) Cancer Res. 55:2528.

6. Cui, X.-D. et al. (2010) Int. J. Cancer 126:940.

7. Finne, E.F. et al. (2004) Biochem. J. 379:39.

8. Takahashi, H. and T. Ikeda (1995) Oncogene 11:879.

9. Wohlfahrt, J.G. et al. (2004) J. Immunol. 172:843.

10. Aasheim, H.-C. et al. (2005) Blood 105:2869.

11. Ogawa, K. et al. (2000) Oncogene 19:6043.

12. Liu, D.-P. et al. (2007) Int. J. Oncol. 30:865.

13. Brantley-Sieders, D.M. et al. (2006) Cancer Res. 66:10315.

14. Pandey, A. et al. (1995) Science 268:567.

15. Magal, E. et al. (1996) J. Neurosci. Res. 43:735.

• Entrez Gene IDs:

  1942 (Human); 13636 (Mouse)

• Alternate Names:

  B61; ECKLG; EFL1; EFL-1; EFNA1; EPH-related receptor tyrosine kinase ligand 1; EphrinA1; Ephrin-A1; EPLG1TNF alpha-induced protein 4; Immediate early response protein B61; LERK1; LERK1LERK-1; ligand of eph-related kinase 1; TNFAIP4B61; Tumor necrosis factor alpha-induced protein 4; tumor necrosis factor, alpha-induced protein 4