Membrane receptors: structure and function of the relaxin family peptide receptors.
The receptors for members of the relaxin peptide family have only recently been discovered and are G-protein-coupled receptors (GPCRs). Relaxin and insulin-like peptide 3 (INSL3) interact with the leucine-rich-repeat-containing GPCRs (LGRs) LGR7 and LGR8, respectively. These receptors show closest similarity to the glycoprotein hormone receptors and contain large ectodomains with 10 leucine-rich repeats (LRRs) but are unique members of the LGR family (class C) as they have an LDL class A (LDLa) module at their N-terminus. In contrast, relaxin-3 and INSL5 interact with another class of type I GPCRs which lack a large ectodomain, the peptide receptors GPCR135 and GPCR142, respectively. These receptors are now classified as relaxin family peptide (RXFP) receptors, RXFP1 (LGR7), RXFP2 (LGR8), RXFP3 (GPCR135) and RXFP4 (GPCR142). This review outlines the identification of the peptides and receptors, their expression profiles and physiological roles and the functional interactions of the peptides with their unique receptors.
Kong
Roy C K
RC
Florey Neuroscience Institutes, University of Melbourne, Victoria 3010, Australia.
Shilling
Patrick J
PJ
Lobb
Derek K
DK
Gooley
Paul R
PR
Bathgate
Ross A D
RA
D000595:Amino Acid Sequence; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D018000:Receptors, Peptide / Q000737:chemistry* / Q000378:metabolism*; D012065:Relaxin / Q000737:chemistry* / Q000378:metabolism*
D018000:Receptors, Peptide; D012065:Relaxin