IL1RAPL1 is a member of the interleukin 1 receptor family and is similar to the interleukin 1 accessory proteins. This protein has an N-terminal signal peptide, three extracellular immunoglobulin Ig-like domains, a transmembrane domain, an intracellular Toll/IL-1R domain, and a long C-terminal tail which interacts with multiple signaling molecules. Deletions and mutations in this gene were found in patients with intellectual disability. Its expression in post-natal brain structures involved in the hippocampal memory system suggests a role in the processes underlying memory and learning abilities, and role in synapse formation and stabilization.