FIGURE 1.

Identification and cloning of GPR31. A, 43 candidate GPCRs have been identified as potential receptors for lipid ligands. The phylogenic tree was constructed based on the similarity level of their amino acid sequences. B, specific binding of 12-(S)- [³H]HETE in PC3 cell membranes. PC3 cell membranes were incubated with 0–50 nm of 12-(S)-[³H]HETE in the absence or presence of 50 μm non-radioactive 12-(S)-HETE. The specific binding was measured as described under “Experimental Procedures.” C, 16 of these candidate GPCRs were cloned from PC3 cells, and transiently transfected into CHO cells for 12-(S)- [³H]HETE (10 nm) binding assay. Note that transfection of GPR31 construct results in a 5.4-fold increase in 12-(S)-[³H]HETE binding.