Structure and function of LGR5: An enigmatic G-protein coupled receptor marking stem cells

Abstract

G-protein coupled receptors (GPCRs) are an important class of membrane protein that transmit extracellular signals invoked by sensing molecules such as hormones and neurotransmitters. GPCR dysfunction is implicated in many diseases and hence these proteins are of great interest to academia and the pharmaceutical industry. Leucine-rich repeat-containing GPCRs contain a characteristic extracellular domain that is an important modulator of intracellular signaling. One member of this class is the leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5), a stem cell marker in intestinal crypts, and mammary glands. LGR5 modulates Wnt signaling in the presence of the ligand R-spondin (RSP..