This gene encodes a member of the G-protein coupled receptor 1 family. The encoded protein is a receptor for cysteinyl leukotrienes, and is involved in mediating bronchoconstriction via activation of a phosphatidylinositol-calcium second messenger system. Activation of the encoded receptor results in contraction and proliferation of bronchial smooth muscle cells, eosinophil migration, and damage to the mucus layer in the lung. Upregulation of this gene is associated with asthma and dysregulation may also be implicated in cancer. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Aug 2013]