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Overexpression of beta-arrestin and beta-adrenergic receptor kinase augment desensitization of beta 2-adrenergic receptors

, , , , , , and . J Biol Chem, 268 (5): 3201-8 (February 1993)Pippig, S Andexinger, S Daniel, K Puzicha, M Caron, M G Lefkowitz, R J Lohse, M J Research Support, Non-U.S. Gov't United states The Journal of biological chemistry J Biol Chem. 1993 Feb 15;268(5):3201-8..

Abstract

Receptor-specific or homologous desensitization of beta 2-adrenergic receptors is thought to be effected via phosphorylation of the receptor by the beta-adrenergic receptor kinase (beta ARK), followed by binding of beta-arrestin. We have generated stably transfected Chinese hamster ovary cell lines overexpressing either of the two regulatory proteins and also expressing low or high levels of beta 2-adrenergic receptors (approximately 80 and approximately 600 fmol/mg of membrane protein). In these cells, we studied the process of desensitization induced by the beta-adrenergic receptor agonist isoproterenol. In cells expressing high levels of beta 2-adrenergic receptors, desensitization to high concentrations of isoproterenol (previously shown to be mediated by both beta ARK and protein kinase A) amounted to approximately 50% in control cells, approximately 80% in beta ARK-overexpressing cells, and approximately 90% in beta-arrestin-overexpressing cells. In cells expressing low levels of beta 2-adrenergic receptors, these values were approximately 50, approximately 60, and approximately 60%, respectively. Desensitization to low concentrations of isoproterenol (previously shown to be essentially protein kinase A-mediated and not receptor-specific, i.e. heterologous) was not affected by overexpression of either beta ARK or beta-arrestin. These data suggest that in cells expressing high levels of beta 2-adrenergic receptors, beta-arrestin and beta ARK become limiting for homologous receptor desensitization. They provide further support for the involvement of these two proteins in the regulation of beta 2-adrenergic receptor function.

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