Fig. 1.

P. dumerilii possesses both CrzR and AKHR receptor orthologs that are differentially activated by 4 GnRH superfamily ligands. (A) Maximum likelihood phylogeny supporting the assignment of the 3 Platynereis receptors (arrowheads) of the GnRHR superfamily as members of the CrzR and AKHR subfamilies. Non-Platynereis sequences were retrieved from ref. 87 and complemented from the National Center for Biotechnology Information sequence repository. Bootstrap values, where not shown, are ≥55. (B) Receptor–ligand interactions as determined by systematic calcium mobilization assays performed with all receptor–ligand combinations. The table lists half maximal effective concentrations (EC₅₀ values) for significant interactions. See SI Appendix, Fig. S3, for individual analyses.