The leukotriene (LT) receptors are G protein-coupled receptors that bind and are activated by the leukotrienes. They include the following proteins: The leukotriene (LT) receptors are G protein-coupled receptors that bind and are activated by the leukotrienes. They include the following proteins: The recently elucidated CysLTE, represented by GPR99/OXGR1, may constitute a third CysLTR.