Interleukin 20 Receptor Alpha (IL20Ra)

IL20RA is a receptor for interleukin 20 (IL20), a cytokine that may be involved in epidermal function. The receptor of IL20 is a heterodimeric receptor complex consisting of this protein and interleukin 20 receptor beta (IL20B). This gene and IL20B are highly expressed in skin. The expression of both genes is found to be upregulated in Psoriasis. Binding assays using radiolabeled ligand demonstrated that IL20 bound to BHK transfectants expressing both IL20RA and IL20RB, but not to untransfected cells nor to transfectants expressing either receptor subunit alone. Binding of (125)I-labeled IL20 was eliminated in the presence of 100-fold excess of unlabeled IL20 but not in the presence of 100-fold excess of the unrelated cytokine, IL21. The binding data revealed 88,000 IL20 receptors per cell, with a binding affinity of approximately 1.5 nM.