The cysteinyl leukotrienes LTC4, LTD4, and LTE4 are important mediators of human bronchial asthma. Pharmacologic studies have determined that cysteinyl leukotrienes activate at least 2 receptors, the protein encoded by this gene and CYSLTR1. This encoded receptor is a member of the superfamily of G protein-coupled receptors. It seems to play a major role in endocrine and cardiovascular systems. [provided by RefSeq, Jul 2008],function:Receptor for cysteinyl leukotrienes. The response is mediated via a G-protein that activates a phosphatidylinositol-calcium second messenger system. Stimulation by BAY u9773, a partial agonist, induces specific contractions of pulmonary veins and might also have an indirect role in the relaxation of the pulmonary vascular endothelium. The rank order of affinities for the leukotrienes is LTC4 = LTD4 >> LTE4.,similarity:Belongs to the G-protein coupled receptor 1 family.,tissue specificity:Widely expressed, with highest levels in the heart, placenta, spleen, peripheral blood leukocytes and adrenal gland. In lung, expressed in the interstitial macrophages, and slightly in smooth muscle cells.,