Molecular Biology of 2-Adrenergic Receptors

Abstract Affinity purification of the β2-adrenergic receptor from hamster lung has led to the amino acid sequencing of a few of its peptides, followed by the molecular cloning of the corresponding cDNA. Expression of this cDNA confirmed the catecholamine binding properties of the β2-adrenergic receptor. This initial success, that of the cloning of the turkey erythrocyte β1-like and of the platelet α2A-adrenergic receptors, has rapidly led to the identification and cloning by homology of nine different subtypes of α1, α2, and β receptors. All these belong to the very large family of G-protein-coupled membrane receptors, which may include over 1000 proteins that act as receptors for neurotransmitters, hormones, and sensory signals such as light or odors. While a few of the adrenergic receptors had been characterized previously by pharmacologic means, most were actually not known to exist as individual entitles. The "reverse pharmacology" made possible by molecular biology should now lead to the synthesis of new subtype-selective ligands.