Toll receptors in Drosophila: a family of molecules regulating development and immunity.

In recent years, Toll-like receptors (TLRs) have emerged as key receptors which detect microbes and initiate an inflammatory response. The Toll receptor was originally identified and characterized 14 years ago for its role in the embryonic development of the fruit-fly Drosophila melanogaster. Subsequently, it was also shown to be an essential component of the signaling pathway mediating the anti-fungal host defense in this model organism. New factors involved in the activation of the Toll receptor or in intracytoplasmic signaling during the immune response in Drosophila have recently been identified. The existence of significant functional differences between mammalian TLRs and Drosophila Toll receptors is also becoming apparent.