GRK2 and dilated cardiomyopathy: So, high levels of GRK2 (Penela et al., 2006; Montó et al., 2015) and β2-AR (Montó et al., 2015) in myocardium of patients with dilated cardiomyopathy have been described, but our previous results indicate that the expression of GRK2 and β2-ARs decreases in PBMC of the same patients (Montó et al., 2015).