IL-6 receptor alpha, soluble

IL-6 mediates its biological effects through the type I IL-6 receptor system that consists of two chains, IL-6Rα and gp130. While the IL-6Rα chain is the binding component specific to IL-6, the gp130 chain only transmits signals of IL-6 when bound to IL-6Rα. The gp130 can also transmit signals from LIF, OSM, CNTF, IL-11 and CT-1 in conjunction with other receptor subunits. The low-affinity binding site for IL-6 is composed of IL-6Rα alone. IL-6Rα is expressed in a wide range of cells, including T cells, fibroblasts and macrophages. Soluble IL-6Rα, which consists of only the extracellular domain of the IL-6Rα chain, acts as an agonist of IL-6 activity at low concentrations. Recombinant Human sIL-6 Receptor α is a 37.9 kDa glycoprotein corresponding to 339 amino acid residues of the extracellular domain of IL-6Rα. As a result of glycosylation, Recombinant Human sIL-6 Receptor α migrates with an apparent molecular mass of approximately 57-70 kDa by SDS-PAGE gel, under reducing conditions.