LGR7

LGR7, also known as the relaxin/insulin-like family peptide receptor 1 (RXFP1), is a human G protein-coupled receptor that belongs to the leucine-rich repeat-containing GPCR family. It serves as a receptor for relaxin family peptides, with relaxin-2 being its principal endogenous ligand in humans.

The receptor features an extracellular N-terminal domain rich in leucine-rich repeats and a low-density lipoprotein class A-like module, followed by seven transmembrane helices typical of GPCRs. This arrangement, including an LDLa motif, supports ligand binding and receptor activation in RXFP1.

Ligand binding and signaling: Relaxin-2 binds RXFP1 and activates intracellular signaling predominantly through Gs, leading to the stimulation of adenylyl cyclase and an increase in cyclic AMP. Additional signaling through other pathways, such as MAPK cascades, has been described in certain contexts. The LDLa module contributes to ligand binding and receptor function.

Expression and physiological roles: RXFP1 is expressed in reproductive tissues such as the uterus and ovary, as well as the mammary gland, cardiovascular system, kidneys, and parts of the central nervous system. In pregnancy, it supports uterine and cervical remodeling and vasodilation. Across tissues, it participates in tissue remodeling and anti-fibrotic responses, contributing to vascular and reproductive physiology.

Clinical and research context: Due to its involvement in reproduction and tissue remodeling, LGR7/RXFP1 is examined as a potential therapeutic target for infertility, pregnancy-related conditions, fibrosis, and cardiovascular diseases. Ongoing research seeks to clarify tissue-specific signaling, ligand interactions, and regulatory mechanisms of this receptor.