IL18RAP - Interleukin 18 Receptor Accessory Protein | Elisa - Clia - Antibody - Protein

Background

Interleukin 18 Receptor Accessory Protein (IL18RAP) is a critical component of the interleukin-18 (IL-18) receptor complex, which is essential for the immune response. IL18RAP, also known as IL-18 receptor beta (IL-18Rβ), forms a functional receptor complex with Interleukin 18 Receptor 1 (IL18R1 or IL-18Rα). This complex is necessary for high-affinity binding of IL-18 and subsequent signal transduction. IL18RAP is primarily expressed on various immune cells, including T cells, natural killer (NK) cells, macrophages, and dendritic cells. Its role is crucial in mediating immune responses, particularly those involving the production of interferon-gamma (IFN-γ) and other pro-inflammatory cytokines, thereby contributing to both innate and adaptive immunity.

Protein Structure

IL18RAP is a type I transmembrane protein characterized by several structural domains:

• Extracellular Domain: Contains three immunoglobulin (Ig)-like domains essential for ligand binding and receptor dimerization.
• Transmembrane Domain: A single-pass transmembrane region that anchors the protein in the cell membrane.
• Intracellular Domain: Involved in signal transduction, containing motifs necessary for recruiting adaptor proteins such as MyD88 and IL-1 receptor-associated kinases (IRAKs).

Classification and Subtypes

IL18RAP is a member of the interleukin-1 receptor family and does not have distinct subtypes. Instead, its functional diversity arises from its interaction with different components of the IL-18 signaling pathway.

Function and Biological Significance

IL18RAP plays several critical roles in the immune system:

• Formation of IL-18 Receptor Complex: IL18RAP pairs with IL18R1 to form a high-affinity receptor complex for IL-18, which is crucial for initiating IL-18 mediated signaling.
• Signal Transduction: The IL-18 receptor complex activates downstream signaling pathways, including NF-κB and MAPK, leading to the production of IFN-γ and other cytokines.
• Th1 Immune Response: IL18RAP is vital for Th1 cell differentiation and the production of IFN-γ, which is essential for the immune response against intracellular pathogens and tumor cells.
• NK Cell Activation: Enhances the cytotoxic activity of NK cells, contributing to the body's defense mechanisms.

Clinical Issues

Alterations in IL18RAP signaling are associated with various diseases:

• Autoimmune Diseases: Dysregulation of IL18RAP has been linked to autoimmune conditions such as rheumatoid arthritis, Crohn's disease, and psoriasis, where excessive IL-18 signaling contributes to chronic inflammation.
• Infections: Impaired IL18RAP function can lead to reduced immune responses against infections, making individuals more susceptible to viral and bacterial pathogens.
• Cancer: Abnormal IL18RAP signaling can influence tumor progression by affecting immune surveillance and the inflammatory environment within tumors.

Summary

IL18RAP (Interleukin 18 Receptor Accessory Protein) is an essential component of the IL-18 receptor complex, playing a pivotal role in immune responses by facilitating IL-18 signaling. Structurally, it comprises extracellular Ig-like domains, a transmembrane region, and an intracellular signaling domain. IL18RAP is crucial for the formation of the IL-18 receptor complex, signal transduction, and the activation of Th1 cells and NK cells. Dysregulation of IL18RAP is implicated in autoimmune diseases, infections, and cancer, highlighting its significance in both health and disease. Understanding IL18RAP's functions and mechanisms provides insights into potential therapeutic targets for modulating immune responses.