Direct evidence for multiple endothelin receptors.
Competition binding experiments and peptide mapping techniques were employed in order to directly address the possible existence of endothelin (ET) receptor subtypes in the atria. Competition binding assays for 125I-labeled ET-1 or 125I-labeled ET-3 to bovine atrial membrane preparations suggest the existence of two ET receptor subtypes, one of which binds ET-1 and ET-3 with a similar affinity while the other shows preference for ET-3. However, cross-linking experiments of both peptides to this tissue resulted in the identification of a single 50-kDa protein. To identify directly the existence of multiple ET receptors, peptide mapping of cross-linked 125I-labeled ET-1 or 125I-labeled ET-3 receptors was conducted. Different peptide maps were obtained only under conditions that preferentially label one receptor subtype. These results indicate, for the first time, the existence of two ET receptor subtypes in the atria which differ from each other in both their binding characteristics and primary structure.
Schvartz
I
I
Division of Endocrinology, Glaxo Research Institute, Research Triangle Park, North Carolina 27709.
Ittoop
O
O
Hazum
E
E
D000818:Animals; D001667:Binding, Competitive; D002417:Cattle; D002531:Cerebellum / Q000737:chemistry / Q000378:metabolism; D003432:Cross-Linking Reagents; D016232:Endothelins / Q000378:metabolism*; D006325:Heart Atria / Q000737:chemistry / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D010449:Peptide Mapping; D011956:Receptors, Cell Surface / Q000737:chemistry* / Q000378:metabolism; D017466:Receptors, Endothelin
D003432:Cross-Linking Reagents; D016232:Endothelins; D008565:Membrane Proteins; D011956:Receptors, Cell Surface; D017466:Receptors, Endothelin