Ephrin-A1/EFNA1 Protein, Human (AAH32698.1, HEK293, His)

Ephrin-A1/EFNA1 Protein is a member of the A-type ephrin family of cell surface proteins that function as ligands for the A-type Eph receptor tyrosine kinase family (EphA2). EFNA1 exerts its function largely through interactions with EphA2. EFNA1 exists in a soluble form as well as a glycophosphatidylinositol (GPI) membrane attached form. EFNA1 acts as a membrane-bound, GPI-anchored protein capable of mediating juxtacrine signalling and requiring membrane attachment or clustering/oligomerization. EFNA1 is a novel TNF-inducible protein. EFNA1 efficiently binds to the EphA8 receptor expressed in NIH3T3 fibroblasts. EFNA1 stimulates PI3K activity via direct interaction of EphA2 with the p85 subunit of PI3K. EFNA1 can both inhibit and stimulate oncogenesis, depending on the cellular context^[1][2][3]. Ephrin-A1/EFNA1 Protein, Human (AAH32698.1, HEK293, His) is the recombinant human-derived Ephrin-A1/EFNA1 protein, expressed by HEK293 , with C-6*His labeled tag. The total length of Ephrin-A1/EFNA1 Protein, Human (AAH32698.1, HEK293, His) is 164 a.a., with molecular weight of 25-30 kDa.

The ephrin family consists of eight members, divided into A and B subclasses based on their mode of cell membrane attachment. Ephrin-A1-A5 are linked to the membrane via a Glycosylphosphatidylinositol (GPI) moiety, while ephrin-B1-B3 are anchored by a transmembrane domain and contain a cytoplasmic tail. Due to their membrane localization, ephrins are able to engage in both forward and reverse signaling^[1].
The G-H loop of ephrin-A1, a highly conserved region of 15 amino acids that connects the G and H β-strands, is inserted into a channel on the surface of EphA2 to form a heterodimeric, 1:1 ligand/receptor complex. Ligand binding of ephrin-A1 induces EphA2 autophosphorylation and interaction with c-Cbl followed by internalization and degradation of the receptor^[1].
EphA2 activation by ephrin-A1 decreases cell attachment to ECM and counteracts integrin signalling in multiple cells types leading to Rac-mediated upregulation of Rho activity. ephrin-A1 stimulation of EphA2 leads to the inhibition of both basal and EGF-induced MAPK activity^[1].
The overexpression of the membrane attached form of EFNA1 suppresses growth of HeLa cells in 3D but not 2D. Knockdown of endogenous EFNA1, or overexpression of full-length EFNA1, resulted in relocalization of EPHA2 from the cell surface to sites of cell-cell contact. Overexpression of soluble EFNA1 however resulted in more EPHA2 distributed on the cell surface, away from cell-cell contacts, and promoted the growth of HeLa cells^[2].
EFNA1 binding to CD4+ T cells stimulates both stromal cell-derived factor 1alpha (SDF-1alpha)- and macrophage inflammatory protein 3beta (MIP3beta)-mediated chemotaxis^[3].

1.Immobilized Human Ephrin-A1-His at 10 μg/mL (100 μl/well) can bind Human EphA2-Fc.The ED₅₀ for this effect is 12.71 ng/mL.
2.Measured by its binding ability in a functional ELISA. When Recombinant Human (rh) EphA2 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 4.998 ng/mL.

• 
  Measured by its binding ability in a functional ELISA. When Recombinant Human (rh) EphA2 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 4.998 ng/mL.

Human

HEK293

C-6*His

AAH32698.1/NP_004419.2 (D19-S182)

1942  [NCBI]

DRHTVFWNSSNPKFRNEDYTIHVQLNDYVDIICPHYEDHSVADAAMEQYILYLVEHEEYQLCQPQSKDQVRWQCNRPSAKHGPEKLSEKFQRFTPFTLGKEFKEGHSYYYISKPIHQHEDRCLRLKVTVSGKITHSPQAHDNPQEKRLAADDPEVRVLHSIGHS

25-30 kDa

• 
  Greater than 95% as determined by reducing SDS-PAGE.

Lyophilized powder

Lyophilized from a 0.2 μm filtered solution of 20 mM Tris-HCl, 4% Trehalose, 4% Mannitol, 0.02% Tween 80, pH 8.0 or 20 mM PB, 150 mM NaCl, pH 7.4.

<1 EU/μg, determined by LAL method.

It is not recommended to reconstitute to a concentration less than 100 μg/mL in ddH₂O.

Stored at -20°C for 2 years. After reconstitution, it is stable at 4°C for 1 week or -20°C for longer (with carrier protein). It is recommended to freeze aliquots at -20°C or -80°C for extended storage.

Room temperature in continental US; may vary elsewhere.