Signal switching after stimulation of LGR7 receptors by human relaxin 2

Ann N Y Acad Sci. 2005 May:1041:288-91. doi: 10.1196/annals.1282.042.


Previous studies have described a biphasic cAMP response after stimulation of LGR7 by human gene 2 (H2) relaxin, involving both adenylate cyclase and PI3-kinase activity. The current study identifies the upstream involvement of Gi in the PI3-kinase-mediated response, likely the result of receptor signal switching. Amino acid sequence analysis of the LGR7 C-terminal tail and intracellular loops revealed multiple putative phosphorylation sites, suggesting that signal switching from Gs to Gi may occur after receptor phosphorylation. This study supports a time-dependent biphasic cAMP response: an initial short Gs-adenylate cyclase-mediated cAMP response is followed by receptor signal switching to a Gi-PI3-kinase-mediated response.

MeSH terms

  • Cell Line
  • Cyclic AMP / metabolism
  • Heterotrimeric GTP-Binding Proteins / metabolism
  • Humans
  • Membrane Proteins / metabolism*
  • Receptors, G-Protein-Coupled / metabolism*
  • Receptors, Peptide
  • Relaxin / metabolism*
  • Signal Transduction*


  • Membrane Proteins
  • RLN2 protein, human
  • RXFP1 protein, human
  • Receptors, G-Protein-Coupled
  • Receptors, Peptide
  • Relaxin
  • Cyclic AMP
  • Heterotrimeric GTP-Binding Proteins