BETA-ARRESTIN - A PROTEIN THAT REGULATES BETA-ADRENERGIC-RECEPTOR FUNCTION

Homologous or agonist-specific desensitization of β-adrenergic receptors is thought to be mediated by a specific kinase, the β-adrenergic receptor kinase (IARK). However, recent data suggest that a cofactor is required for this kinase to inhibit receptor function. The complementary DNA for such a cofactor was cloned and found to encode a 418-amino acid protein homologous to the retinal protein arrestin. The protein, termed β-arrestin, was expressed and partially purified. It inhibited the signaling function of βARK-phosphorylated β-adrenergic receptors by more than 75 percent, but not that of rhodopsin. It is proposed that β-arrestin in concert with βARK effects homologous desensitization of β-adrenergic receptors.