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Interaction between β-adrenergic receptors and guanine nucleotide sites in turkey erythrocyte membranes

par Vauquelin, Georges;Bottari, Serge P. ;Andre, Claudine;Jacobsson, Bo;Strosberg, Arthur
Référence Proceedings of the National Academy of Sciences of the United States of America, 77, 7 II, page (3801-3805)
Publication Publié, 1980

Article révisé par les pairs

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Résumé :

β1-Adrenergic receptors from turkey erythrocyte membranes have been identified by specific binding of the radiolabeled antagonist (-)-[ 3H]dihydroalprenolol. These receptors are inactivated by the alkylating agent N-ethylmaleimide when occupied by β-adrenergic agonists but not when occupied by antagonists or when unoccupied. A time-dependent decrease of the number of receptor sites is observed. Inactivation affects 45-60% of the sites, regardless of the agonist or N-ethylmaleimide concentration. The guanine nucleotides GTP and 5'-guanylyl imidodiphosphate effectively protect the receptors, against agonist-mediated inactivation by N-ethyl-maleimide. Protection by ATP necessitates a 100-fold higher concentration; 10mM NaF is ineffective. The guanine nucleotide effect is reversible and occurs via interaction with N-ethylmaleimide-insensitive sites. These observations establish that guanine nucleotide sites interact with and cause structural modification of the agonist-occupied β-adrenergic receptors in turkey erythrocyte membranes.