Cloning, sequencing and tissue distribution of two related G protein-coupled receptor candidates expressed prominently in human lung tissue.

A novel G protein-coupled receptor, named GPR12A, was cloned by a PCR strategy using degenerate primers designed from sequences conserved among receptors for inflammatory mediators. Screening of a human lung cDNA library with GPR12A as a probe also identified a closely-related cDNA (GPR6C.1) that has been previously reported as GPR4 [13]. GPR12A and GPR6C.1 are 46.1% identical in amino acid sequence, but are less than 33% identical to any other known receptors. Northern analysis revealed that they are expressed prominently in the lung. Although the ligands for GPR12A and GPR6C.1 are unknown, their similarity suggests that they are receptors for ligands of similar or identical chemical nature.