IL1RL1 is a symbol for the gene, Interleukin 1 receptor-like 1, in humans. Other names include: Interleukin-1 receptor-like 1; Protein ST2; homolog of mouse growth stimulation-expressed; DER4; FIT-1; IL33R; ST2L; ST2V. The encoded protein has an amino acid length of 556 and a mass of 63.4 kDa. Other isoforms may exist. IL1RL1 is a member of the Interleukin-1 receptor family. This gene shares homology with other species, including: Mouse, Rat, Zebrafish, Chicken.