The receptor for interleukin 20 is a heterodimer of 2 orphan class II cytokine receptor subunits, IL20RA, also called ZCYTOR7, and IL20RB, also called DIRS1. Binding assays 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. Both receptor subunits were expressed in skin and were dramatically upregulated in psoriatic skin.Synonyms: Cytokine receptor class-II member 8, Cytokine receptor family 2 member 8, IL-20R-alpha, IL-20R1, Interleukin-20 receptor alpha chain, ZCYTOR7