IL1R2

Interleukin-1 receptor type 2 (IL1R2) is a member of the interleukin-1 receptor family encoded by the IL1R2 gene. It is best known for acting as a decoy receptor that modulates inflammatory signaling by binding interleukin-1 (IL-1) ligands and reducing their interaction with signaling receptors.

IL1R2 is a transmembrane protein with an extracellular ligand-binding domain similar to IL-1 receptor type I (IL1R1) but lacking a functional cytoplasmic signaling domain. Consequently, IL1R2 does not transduce signals when it binds IL-1. A soluble form of IL1R2 can also arise from alternative processing or shedding, contributing to extracellular sequestration of IL-1 in the circulation or tissues.

Ligand binding by IL1R2 includes IL-1α and IL-1β, the principal proinflammatory cytokines of the IL-1 family. By capturing these cytokines, IL1R2 reduces the availability of IL-1 to interact with IL1R1 and its coreceptor IL1RAP, thereby dampening downstream inflammatory pathways. In some contexts, interaction with IL-1 receptor antagonists can further influence the local balance of IL-1 activity.

Expression of IL1R2 is found across a range of tissues and cell types, including monocytes, neutrophils, dendritic cells, and endothelial cells. Its expression can be modulated by inflammatory stimuli, contributing to negative feedback regulation of IL-1–driven responses.

Clinically, altered IL1R2 expression or soluble IL1R2 levels have been observed in various inflammatory and autoimmune conditions, sepsis, and certain cancers. As a decoy receptor, IL1R2 is studied for its potential as a biomarker of inflammation and as a target to modulate IL-1–mediated pathology.

Related genes include IL1R1 (the signaling IL-1 receptor) and IL1RN (the IL-1 receptor antagonist).