GRK5 and hypertrophy: Of note, we have previously shown transgenic mice with cardiomyocyte-specific GRK5 overexpression (TgGRK5) to have increased cardiac hypertrophy and functional impairments, while cardiomyocyte-specific GRK5 knockout mice (GRK5cKO) develop less hypertrophy and maintain better cardiac function after transverse aortic constriction (TAC).9