Various members of the GRK family phosphorylate activated Agtr1 receptors to elicit distinct responses. Grk5 and 6 appear to favor Arrb2-mediated activation of Erk1/2 MAPK cascade while Grk2 and 3 disfavor it. Different patterns of receptor phosphorylation may lead to differential recruitment of Arrb proteins but the exact mechanisms by which GRK members impact on events downstream of the receptors remain to be established. For more information check PMID 16304060 and references therein. The members of the GRK family are listed with aliases in parentheses, full names and links to gene report pages:

Grk2 (Adrbk1, Grk-2, BARK1) – G protein-coupled receptor kinase 2
Grk3 (Adrbk2, Grk-3, BARK2) – G protein-coupled receptor kinase 3
Grk5 (Gprk5) – G protein-coupled receptor kinase 5
Grk6 (Gprk6) – G protein-coupled receptor kinase 6