title: A horseshoe crab receptor structurally related to Drosophila Toll.
abstract: Innate immunity against microbial pathogens relies on the pattern recognition of cell wall components on invading microbes. Recent evidence has shown that a mammalian Toll-like receptor (TLR) is activated by bacterial lipopolysaccharides (LPS). The innate immunity in invertebrates is also triggered by LPS, as seen in the hemolymph coagulation in horseshoe crab. We report the cloning of a TLR from the Japanese horseshoe crab Tachypleus tridentatus. A cDNA coding for Tachypleus Toll was isolated from a hemocyte cDNA library and the open reading frame codes for a proprotein including a signal sequence. Like Drosophila Toll, Tachypleus Toll is a type I transmembrane protein with an extracellular domain consisting of two leucine-rich repeats flanked by two cystein-rich clusters and a cytoplasmic domain exhibiting striking similarity with the cytoplasmic domain of interleukin-1 receptor. Tachypleus Toll is most similar to Drosophila Toll in the domain architecture and the overall length.
authors.affiliation: Department of Molecular Biology, Kyushu University, Fukuoka, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Inamori
authors.forename: K
authors.initials: K
authors.lastname: Koori
authors.forename: C
authors.initials: C
authors.lastname: Mishima
authors.forename: T
authors.initials: T
authors.lastname: Muta
authors.forename: S
authors.initials: S
authors.lastname: Kawabata
mesh_terms: D000818:Animals; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004330:Drosophila / Q000235:genetics / Q000276:immunology*; D029721:Drosophila Proteins; D006737:Horseshoe Crabs / Q000235:genetics / Q000276:immunology*; D019476:Insect Proteins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface; D013045:Species Specificity; D051193:Toll-Like Receptors
chemical_list: D018076:DNA, Complementary; D029721:Drosophila Proteins; D019476:Insect Proteins; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; C068721:Tl protein, Drosophila; D051193:Toll-Like Receptors