Cloning and functional expression of human cDNA for the ETB endothelin receptor.

We report the cloning of human cDNA encoding an ETB (non-isopeptide-selective) subtype of the endothelin receptor. The predicted amino acid sequence of the human ETB endothelin receptor was 87.8% and 62.9% identical with the previously cloned rat ETB and ETA receptors, respectively. COS cells transiently transfected with the cloned cDNA expressed specific, high-affinity binding sites for endothelin isopeptides and responded to the peptides with a transient increase of [Ca2+]i; endothelin-1 and endothelin-3 exhibited approximately equal potencies both in displacing 125I-labeled endothelin-1 binding and in eliciting [Ca2+]i transients. The ETB receptor mRNAs were expressed in various human tissues and also in the intact porcine aortic intimal cells ex vivo.