Fusion protein amino acids 381-590 (C-terminus) of mouse GRK5 (also known as G protein-coupled receptor kinase 5 and Gprk5, accession number Q8VEB1) Rat: 99% identity (208/210 amino acids identical) Human: 91% identity (193/210 amino acids identical) >55% identity with GRK6 and GRK4 >40% identity with GRK7 and RK