Granulocyte Macrophage Colony Stimulating Factor Receptor alpha (GM-CSF R, CD116), human recombinant

Granulocyte macrophage colony stimulating fact or receptor alpha (GM­CSF Ralpha) , also known as CD116, is a component of the receptor complex that mediates cellular responses to GM­CSF. GM­CSF promotes the differentiation and mobilization of granulocyte­macrophage, erythroid, megakaryocyte, and eosinophil progenitors. It enhances the activation of myeloid cell effect or functions and plays a role in the development of Th1 biased immune responses, allergic inflammation, and autoimmunity (1 ­ 4). Mature human GM­CSF Ralpha is an 80kD type I transmembrane glycoprotein that consists of a 298 amino acid (aa) extracellular domain (ECD) with two fibronect in type III domains and a juxtamembrane WSXWS motif , a 26 aa transmembrane segment , and a 54 aa cytoplasmic domain (5). Within the ECD, human GM­CSF Ralpha shares approximately 33% aa sequence identity with mouse and rat GM­CSF Ralpha. Alternate splicing of human GM­CSF Ralpha generates several additional isoforms that lack the cytoplasmic and/or transmembrane regions. Soluble forms of the receptor retain the ability to bind GM­CSF ( 6, 7) . GM­CSF Ralpha is expressed on hematopoieticstem cells, progenitor and differentiated cells in the myeloid lineage, vascular endothelial cells, placenta, and non­hematopoietic solid tumor cells (8). GM­CSF Ralpha associates with the common beta chain/CD131 (beta c ), a135kD transmembrane protein that is also the signal transducing component of the receptors for I L­3 and IL­5 (9,10). Association with beta c convert s GM­CSF Ralpha from a low affinity to a high affinity receptor for GM­CSF ( 9 ­ 11). The shared usage of beta c underlies the synergism between GM­CSF, I L­3, and I L­5 in their effects on myeloid cell differentiation and activation (1, 2). Recombinant protein corresponding to human Leu20-Gly320, with a C-terminal 10-His tag expressed in NSO cells (P15509) , Activity: , Measured by its ability to inhibit GMCSFdependent proliferation of TF1 human erythroleukemic cells. The ED50 for this effect is typically 1.25ug/ml in the presence of 40pg/ml of rhGMCSF. Applications: Suitable for use in ELISA. Other applications not tested. Recommended Dilution: Optimal dilutions to be determined by the researcher. Storage and Stability: Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute with sterile buffer. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Reconstituted product is stable for 6 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.