The function of RXFP4 (relaxin family peptide/INSL5 receptor 4, ENSG00000173080) is as follows. High affinity receptor for INSL5. Also acts as a receptor for RLN3/relaxin-3, as well as bradykinin and kallidin. Binding of the ligand inhibit cAMP accumulation. {ECO:0000269|PubMed:14522967, ECO:0000269|PubMed:15525639}.