Within the IL18 receptor complex, does not mediate IL18- binding, but involved in IL18-dependent signal transduction, leading to NF-kappa-B and JNK activation (PubMed:14528293, PubMed:25500532, PubMed:9792649). May play a role in IL18-mediated IFNG synthesis from T-helper 1 (Th1) cells (Probable). {ECO:0000269|PubMed:14528293, ECO:0000269|PubMed:25500532, ECO:0000269|PubMed:9792649, ECO:0000305|PubMed:10653850}. This is the function of Ensembl gene identifier ENSG00000115607 (IL18RAP, interleukin 18 receptor accessory protein).