| abstract |
relaxin receptor 1 (or LGR7), member of the class A family of seven-transmembrane G protein-coupled receptors. Relaxin is a member of the insulin superfamily that has diverse actions in both reproductive and non-reproductive tissues. The relaxin-like peptide family includes relaxin-1, relaxin-2, and the insulin-like (INSL) peptides such as INSL3, INSL4, INSL5 and INSL6. The relaxin family peptides share high structural but low sequence similarity, and exert their physiological functions by activating a group of four G protein-coupled receptors, RXFP1-4. Relaxin is the endogenous ligand for RXFP1, which has a large extracellular N-terminal domain containing 10 leucine-rich repeats and a unique low-density lipoprotein type A (LDLa) module which is necessary for receptor activation. Upon receptor binding, relaxin activates a variety of signaling pathways to produce second messengers such as cAMP and nitric oxide. RXFP1 is expressed in various tissues including uterus, ovary, placenta, cerebral cortex, heart, lung and kidney, among others. |