OXGR1

OXGR1, i.e., 2-oxoglutarate receptor 1 (also known as GPR99, cysteinyl leukotriene receptor E, i.e., CysLT_E, and cysteinyl leukotriene receptor 3, i.e., CysLT3) is a G protein-coupled receptor located on the surface membranes of certain cells. It functions by binding one of its ligands and thereby becoming active in triggering pre-programmed responses in its parent cells. OXGR1 has been shown to be activated by α-ketoglutarate, itaconate, and three cysteinyl-containing leukotrienes (abbreviated as CysLTs), leukotriene E4 (i.e., LTE4), LTC4, and LTD4. α-Ketoglutarate and itaconate are the dianionic forms of α-ketoglutaric acid and itaconic acid, respectively. α-Ketoglutaric and itaconic acids are short-chain dicarboxylic acids that have two carboxyl groups (notated as -CO₂H) both of which are bound to hydrogen (i.e., H⁺). However, at the basic pH levels (i.e., pH>7) in virtually all animal tissues, α-ketoglutaric acid and itaconic acid exit almost exclusively as α-ketoglutarate and itaconate, i.e., with their carboxy residues being negatively charged (notated as -CO₂${\displaystyle ^{-}}$), because they are not bound to H⁺ (see Conjugate acid-base theory). It is α-ketoglutarate and itaconate, not α-ketoglutaric or itaconic acids, which activate OXGR1.