Methods for treating cardiovascular disease, and in particular heart failure, are provided comprising administering a therapeutically effective amount of a modulator of SERCA2a post-translation modification such as SUMOylation or acetylation. Also provided are methods of treating cardiovascular disease by inhibiting SERCA2a degradation. Further provided are methods of diagnosing a propensity to develop heart failure comprising determining if a SERCA2a mutant is present or determining the level of expression of SUMO1 in cardiomyocytes. The disclosure also provides methods of screening for therapeutics that modulate the post-translational modification of SERCA2a, such as by modulating post-translational SUMOylation and/or acetylation.