• Purity

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

• Endotoxin Level

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

• Activity

  Measured by its ability to inhibit LIF-dependent proliferation of TF?1 human erythroleukemic cells. Kitamura, T.     et al. (1989) J. Cell Physiol.     140:323. The ED    ₅₀ for this effect is typically 1-6 μg/mL in the presence of 0.3 ng/mL of recombinant human LIF.

• Source

  Human embryonic kidney cell, HEK293-derived Met1-Ser833

• Accession #

• N-terminal Sequence    
  Analysis

  Gln45 predicted: No result obtained, sequencing might be blocked

• Predicted Molecular Mass

  89.4 kDa

• SDS-PAGE

  110-140 kDa, reducing conditions

Background: LIF R alpha

Leukemia Inhibitory Factor Receptor alpha (LIF R alpha ), also known as LIFR beta and CD118, is a 190 kDa type I transmembrane protein in the Interleukin-6 receptor family. Members of this family mediate the biological effects of Cardiotrophin-1, CLC, CNTF, IL-6, IL-11, IL-27, and Oncostatin M (1). Mature human LIF R alpha consists of a 789 amino acid (aa) extracellular domain (ECD) with two cytokine receptor homology domains, one WSxWS motif, and three fibronectin type III repeats, followed by a 25 aa transmembrane segment and a 239 aa cytoplasmic domain (2). Within the ECD, human LIF R alpha shares 72% aa sequence identity with mouse and rat LIF R alpha. LIF R alpha binds the pleiotropic cytokine LIF with low affinity (3). Binding affinity is increased by the ligand-induced association of LIF R alpha with the signal transducing subunit gp130 (4, 6). The LIF R alpha /gp130 receptor complex also transduces Oncostatin M signals, although LIF R alpha alone does not interact with Oncostatin M (4). gp130 associates with different ligand-specific receptors to form signaling receptor complexes for the other IL-6 family ligands (1). The CNTF receptor is a ternary complex that contains CNTF R alpha and gp130 as well as LIF R alpha (6, 7). LIF R alpha is widely expressed, and LIF induces the proliferation, differentiation, and activation of cells in many tissues (8, 9). In particular, LIF R alpha plays an important role in several aspects of early pregnancy such as blastocyst implantation in the uterus (10-12).

• References:

1. Muller-Newen, G. (2003) Science STKE 2003:pe40.

2. Gearing, D.P. et al. (1991) EMBO J. 10:2839.

3. Layton, M.J. et al. (1992) Proc. Natl. Acad. Sci. 89:8616.

4. Gearing, D.P. et al. (1992) Science 255:1434.

5. Giese, B. et al. (2005) J. Cell Sci. 118:5129.

6. Ip, N.Y. et al. (1992) Cell 69:1121.

7. Davis, S. et al. (1993) Science 260:1805.

8. Metcalf, D (2003) Stem Cells 21:5.

9. Kubota, Y. et al. (2008) J. Clin. Invest. 118:2393.

10. Paiva, P. et al. (2009) Cytokine Growth Factor Rev. 20:319.

11. Stewart, C.L. et al. (1992) Nature 359:76.

12. Cheng, J.-G. et al. (2001) Proc. Natl. Acad. Sci. 98:8680.

• Long Name:

  Leukemia Inhibitory Factor Receptor alpha

• Entrez Gene IDs:

  3977 (Human); 16880 (Mouse); 81680 (Rat)

• Alternate Names:

  CD118 antigen; CD118; FLJ98106; FLJ99923; leukemia inhibitory factor receptor alpha; leukemia inhibitory factor receptor; LIF R alpha; LIF R beta; LIF receptor; LIFR; LIF-R; LIFRa; SJS2; STWS; SWS