Relaxin/Insulin Like Family Peptide Receptor 1 (RXFP1)

The deduced 757- and 723-amino acid LGR7 proteins are 33% identical to snail Lgr. They contain a low density lipoprotein receptor cysteine-rich motif, 10 LRRs, and 5 N-glycosylation sites in the N terminus; the 7-transmembrane region; and a unique C-terminal tail with a phosphorylation site. Northern blot analysis revealed expression of a 5.5-kb transcript in all rat tissues tested except spleen, and smaller transcripts were found in oviduct, uterus, colon, and brain. Expression of the long and short variants of LGR7 with mutations in transmembrane domain 6 (asp637 to tyr and asp603 to tyr, respectively), but not of wildtype LGR7, resulted in increased basal production of cAMP, as seen in similar experiments with the luteinizing hormone receptor (LHCGR) and the TSH receptor  but not the FSH receptor.