Interleukin-1 receptor family

Members of the very wide interleukin-1 receptor (IL-1R) family are characterized by extracellular immunoglobulin-like domains and intracellular Toll/Interleukin-1 receptor/Resistance protein (TIR) domain. It is a group of structurally homologous proteins, conserved throughout the species as it was identified from plants to mammals. Proteins of this family play important role in host defence, injury and stress. There are four main groups of TIR domain-containing proteins in animals; Toll-like receptors, Interleukin-1 receptor (IL-1R), cytosolic adaptor proteins (such as MyD88 adaptor protein) and insect and nematode Toll. Each of these groups is involved mainly in host defence; Toll receptors are also involved in embryogenesis.