Important for the maintenance of cardiac function (PubMed:40409267). Plays a regulatory function in heart rate dynamics mediated, at least in part, through cAMP-binding and, probably, by increasing cell surface expression of the potassium channel KCNK2 and enhancing current density (PubMed:40409267). {ECO:0000250|UniProtKB:Q6JWV8, ECO:0000250|UniProtKB:Q9ES82, ECO:0000269|PubMed:40409267}. This is the function of ENSG00000121577 (POPDC2, popeye domain cAMP effector 2).