The beta-adrenergic receptor kinase specifically phosphorylates the agonist-occupied form of the beta-adrenergic and related G protein-coupled receptors. Overall, the beta adrenergic receptor kinase 2 has 85 % amino acid similarity with beta adrenergic receptor kinase 1, with the protein kinase catalytic domain having 95 % similarity. These data suggest the existence of a family of receptor kinases which may serve broadly to regulate receptor function.,GRK3,ADRBK2,BARK2,Signal Transduction,G protein signaling,G-Protein-Coupled Receptors(GPCR),Kinase,GRK3