IL-5 receptor alpha (IL-5 Rα), also known as CD125, is a subunit of the functional heterodimeric IL-5 receptor complex.1 IL-5 is produced primarily by activated T cells and mast cells, and has diverse biological effects on a variety of cell types. It is a potent eosinophil differentiation and activation factor. The IL-5Rα chain is exclusively expressed by eosinophils, some basophils and murine B1 cells or B cell precursors.2 The high affinity receptor complex for IL-5 consist of the ligand binding α chain, IL-5 Rα, and the common beta chain, CD131.3 The α-chain exclusively binds IL-5 and the intra-cellular portion of IL-5 Rα is associated with JAK2, a protein tyrosine-kinase essential in IL-5 signal transduction.4,5 The beta subunit is shared with the high affinity receptor complexes IL-3 and GM-CSF. Like many other cytokine receptors, alternative splicing of the IL-5Rα gene results in expression of either a membrane bound or soluble form. The soluble form does not lead to signal transduction and therefore has an antagonistic effect on IL-5 signaling. Soluble IL-5 Rα up-regulation has been shown to be involved with the eosinophil-associated disease nasal polyposis.6
>97% by SDS-PAGE and analyzed by silver stain.
<1.0 EU/µg as determined by the LAL method
Sf 21 Insect Cells
Protein Accession No.
Amino Acid Sequence
dllpdekisl lppvnftikv tglaqvllqw kpnpdqeqrn vnleyqvkin apkeddyetr iteskcvtil hkgfsasvrt ilqndhslla sswasaelha ppgspgtsiv nltcttntte dnysrlrsyq vslhctwlvg tdapedtqyf lyyrygswte ecqeyskdtl grniacwfpr tfilskgrdw lavlvngssk hsairpfdql falhaidqin pplnvtaeie gtrlsiqwek pvsafpihcf dyevkihntr ngylqieklm tnafisiidd lskydvqvra avssmcreag lwsewsqpiy vgnde
N-terminal Sequence Analysis
State of Matter
Predicted Molecular Mass
The predicted molecular weight of Recombinant Human IL-5 Rα is Mr 38 kDa. However, the actual molecular weight as observed by migration on SDS-PAGE is Mr 43 kDa.
This recombinant protein was 0.2 µm filtered and lyophilized from modified Dulbecco’s phosphate buffered saline (1X PBS) pH 7.2 – 7.3 with no calcium, magnesium, or preservatives.
Storage and Stability
This lyophilized protein is stable for six to twelve months when stored desiccated at -20°C to -70°C. After aseptic reconstitution, this protein may be stored at 2°C to 8°C for one month or at -20°C to -70°C in a manual defrost freezer. Avoid Repeated Freeze Thaw Cycles. See Product Insert for exact lot specific storage instructions.
Country of Origin
Next Day Ambient
NCBI Gene Bank
References & Citations
1. Graham, A. et al. (2000) Cytokine 12:858
2. Coffer, PJ. et al. (2001) Cytokine Growth Factor Rev 12:19
3. Fiers, W. et al. (1991) Cell 66:1175
4. Ishikawa, T. et al. (1998) Blood 91:2264
5. Takatsu, K. et al. (1994) J. Exp. Med. 14:7404
6. Tavernier, J. et al. (2003) Allergy 58:371
IMPORTANT Use lot specific datasheet for all technical information pertaining to this recombinant protein.
Products are for research use only. Not for use in diagnostic or therapeutic procedures.