AS105

AS105 (AS-105) is a highly potent, ATP-competitive CaMKII inhibitor, inhibits CaMKIIδ with IC50 of 8 nM, Ki of 3 nM. AS105 is also effective against autophosphorylated CaMKII (in contrast to the commonly used allosteric CaMKII-inhibitor KN-93). In isolated atrial cardiomyocytes from human donors and ventricular myocytes from CaMKIIδC-overexpressing mice with heart failure, AS105 effectively reduced diastolic SR Ca2+ leak by 38% to 65% as measured by Ca2+-sparks or tetracaine-sensitive shift in [Ca2+]i. AS105 effectively reduced SR Ca2+-leak, thus improving SR Ca2+-accumulation and reducing cellular arrhythmogenic correlates, without negatively influencing excitation-contraction coupling.