cysteinyl leukotriene receptor 2, member of the class A family of seven-transmembrane G protein-coupled receptors
Cysteinyl leukotrienes (LTC4, LTD4, and LTE4) are the most potent inflammatory lipid mediators that play an important role in human asthma. They are synthesized in the leucocytes (cells of immune system) from arachidonic acid by the actions of 5-lipoxygenase and induce bronchial constriction through G protein-coupled receptors, CysLTR1 and CysLTR2. Activation of CysLTR1 by LTD4 induces airway smooth muscle contraction and proliferation, eosinophil migration, and damage to the lung tissue. They belong to the class A GPCR superfamily, which all have a common structural architecture comprising of seven-transmembrane (TM) alpha-helices interconnected by three extracellular and three intracellular loops. A general feature of GPCR signaling is agonist-induced conformational changes in the receptors, leading to activation of the heterotrimeric G proteins, which consist of the guanine nucleotide-binding G-alpha subunit and the dimeric G-beta-gamma subunits. The activated G proteins then bind to and activate numerous downstream effector proteins, which generate second messengers that mediate a broad range of cellular and physiological processes.