Characterization of two distinct types of leukotriene B 4 receptor

Abstract

Leukotriene B 4 is an oxygenated product of arachidonic acid, and is one of the most potent chemoattractants, involved in inflammatory and allergic responses. We, as well as others, have cloned two distinct types of leukotriene B 4 receptors [BLTs], and termed them BLT1, and BLT2. Two receptors shared 45% amino acid identity, and exhibited different pharmacological properties (ligand affinity, ligand specificity and antagonist effects), tissue distributions, and intracellular signaling. By binding assay experiments, BLT1 and BLT2 represent, the high-affinity and the low-affinity receptors for LTB 4, respectively. Two receptor genes are clustered on human chromosome 14q, and the open reading frame of BLT2 is present in the promoter region of BLT1, thus suggesting a possible interactive expression of two genes. The biological roles of BLT2 remain to be clarified.