Integral membrane protein GPR137A, an orphan receptor member of the seven-transmembrane G protein-coupled receptor superfamily
GPR137A, also called GPR137 or transmembrane 7 superfamily member 1-like 1 protein (TM7SF1L1), is an orphan G protein-coupled receptor (GPCR) expressed in the central nervous system (CNS), endocrine gland, thymus, and lung. It is associated with different cancers including gastric cancer, pancreatic cancer, colon cancer, and malignant glioma. It is highly expressed in ovarian cancer and plays a pro-oncogenic role in the disease, promoting cell proliferation and metastasis through regulation of the PI3K/AKT pathway. GPCRs transmit physiological signals from the outside of the cell to the inside via G proteins. All GPCRs share 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.