The function of SIGIRR (single Ig and TIR domain containing, ENSG00000185187) is as follows. Acts as a negative regulator of the Toll-like and IL-1R receptor signaling pathways. Attenuates the recruitment of receptor- proximal signaling components to the TLR4 receptor, probably through an TIR-TIR domain interaction with TLR4. Through its extracellular domain interferes with the heterodimerization of Il1R1 and IL1RAP. {ECO:0000269|PubMed:12925853, ECO:0000269|PubMed:14715412, ECO:0000269|PubMed:15866876, ECO:0000269|PubMed:25963006}.