JB Minireview—Lipid Signaling J. Biochem. 132, 1-6 (2002) Leukotriene Receptors: Classification, Gene Expression, and Signal

Leukotrienes (LTs) are potent pro-inflammatory mediators derived from arachidonic acid by the action of 5-lipoxygenase. There are two groups of LTs: LTB4 and cysteinyl LTs (LTC4, LTD4, and LTE4). Both of them play important roles in many inflammatory diseases and allergic responses. Recently, their G-protein coupled receptors have been cloned. The identification of these receptors enables us to analyze their gene structures, regulation of expression, and signal transduction in the cells, and it also leads to the development of useful antagonists. Some LT receptors have been disrupted by gene tar-geting. Such studies may reveal novel functions of leukotrienes, confirming deeper viewpoints for further research. Key words: allergy, chemotaxis, G-protein coupled receptor, inflammation, lipid media-tor. In a biological system, arachidonic acid plays a unique role as a precursor for a series of mediators with wide-ranging effects, known as eicosanoids (from the Greek eicosa = twenty; for twenty carbon fatty acid derivatives). Eico