Molecular biology of adrenergic receptors: model systems for the study of G-protein-mediated signal transduction.
Elucidation of the gene structure of several receptors known to mediate the signal of hormone or transmitter binding to intracellular effector systems through guanine-nucleotide-binding proteins (G proteins) has revealed that these receptors comprise a super-family of related proteins. The hallmark of all G-protein-linked receptors is a presumed topography of 7 membrane-spanning loops, analogous to the structure of bacteriorhodopsin. Members of this gene superfamily contain regions, particularly with the hydrophobic domains, of homologous sequence. The expression of G-protein-linked receptors in heterologous cell systems has allowed for the study of the pharmacological and biochemical properties of individual receptor subtypes in a manner not previously possible with intact tissues containing multiple receptors. Site-directed mutagenesis experiments have identified many conserved amino acids which are involved in ligand binding, receptor activation by agonists and receptor-G protein coupling, and suggest that the conservation of receptor structure throughout this gene family may reflect a conservation of important functional domains within these proteins.
Fraser
C M
CM
Section on Molecular Neurobiology, National Institute on Alcohol Abuse and Alcoholism, Rockville, Md.
D000595:Amino Acid Sequence; D000818:Animals; D019204:GTP-Binding Proteins / Q000502:physiology*; D015870:Gene Expression; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011942:Receptors, Adrenergic, alpha / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D011943:Receptors, Adrenergic, beta / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*
D011942:Receptors, Adrenergic, alpha; D011943:Receptors, Adrenergic, beta; D019204:GTP-Binding Proteins