Description
Interleukin-1 receptor-like 1, also known as protein ST2, IL1RL1 and DER4, is a single-pass type I membrane and a secreted protein which belongs to the interleukin-1 receptor family. IL1RL1 / DER4 has a soluble secreted form (sST2) and a transmembrane form (ST2L). IL1RL1 / DER4 contains three Ig-like C2-type (immunoglobulin-like) domains and one TIR domain. IL1RL1 / DER4 is highly expressed in kidney, lung, placenta, stomach, skeletal muscle, colon and small intestine. Isoform A of IL1RL1 is prevalently expressed in the lung, testis, placenta, stomach and colon. Isoform B of IL1RL1 is more abundant in the brain, kidney and the liver. Isoform C of IL1RL1 is not detected in brain, heart, liver, kidney and skeletal muscle. The coding gene forms a cytokine receptor gene cluster together with IL1R1(interleukin 1 receptor, type I), IL1R2 (interleukin 1 receptor, type II) and IL1RL2 (interleukin 1 receptor-like 2) genes in a region mapped to chromosome 2q12. As an important mediator involved in many immune and inflammatory responses, this cytokine has been implicated as a regulator of both the development and effector phases of type 2 helper T cell responses, and as a negative feedback modulator of macrophage pro-inflammatory function. IL33 is a specific ligand of the protein IL1RL1 and induces production of Th2 cytokines