Second immunoglobulin (Ig)-like domain of interleukin-1 receptor-2 (IL1R2), and similar domains
The members here are composed of the second immunoglobulin (Ig)-like domain of interleukin-1 receptor-2 (IL1R2). IL-1 alpha and IL-1 beta are cytokines which participate in the regulation of inflammation, immune responses, and hematopoiesis. These cytokines bind to the IL-1 receptor type 1 (IL1R1), which is activated on additional association with interleukin-1 receptor accessory protein (IL1RAP). IL-1 also binds the IL-1 receptor, type II (IL1R2) represented in this group. Mature IL1R2 consists of three IG-like domains, a transmembrane domain, and a short cytoplasmic domain. It lacks the large cytoplasmic domain of mature IL1R1 and does not initiate signal transduction. A naturally occurring cytokine IL-1RA (IL-1 receptor antagonist) is widely expressed and binds to IL-1 receptors, inhibiting the binding of IL-1 alpha and IL-1 beta.