Human Interleukin 18 Receptor Accessory Protein (IL18RAP) Protein

Background

IL18RAP is an essential co-receptor that forms a heterodimeric complex with IL18R1 to enable IL-18-mediated immune signaling. It enhances the binding affinity of IL-18 to IL18R1, facilitating the recruitment of MyD88 and the activation of downstream signaling pathways, including NF-κB and MAPK, which drive the production of pro-inflammatory cytokines such as IFN-γ. IL18RAP is highly expressed on immune cells such as NK cells, macrophages, and Th1 T cells, where it regulates immune activation, cytokine release, and pathogen defense. It plays a pivotal role in promoting inflammation, antiviral immunity, and anti-tumor responses by enhancing IL-18 signaling efficiency. Dysregulation of IL18RAP is associated with inflammatory diseases, autoimmune disorders, and cancers, where aberrant IL-18 signaling exacerbates tissue damage and immune dysregulation. Functional studies show that loss of IL18RAP impairs IL-18 signaling, reduces cytokine production, and weakens immune responses, highlighting its critical role as a signaling cofactor in inflammation, immune defense, and disease progression.