UCHL1 and heart failure: Our study provides the first genetic evidence that UCHL1 in cardiomyocytes is dispensable for perinatal cardiac development, but post-MI myocardial upregulation of UCHL1 occurs primarily in cardiomyocytes in both mice and humans and this upregulation is indispensable for cardiac proteostasis and protects against post-MI cardiac remodeling and heart failure.