FIS1 and myocardial infarction: In myocardial infarction, the upregulation of ubiquitin ligase SIAH2 can suppress Drp1-Ser637 phosphorylation via the A-kinase anchoring protein 121 (AKAP121)/PKA pathway, thereby enhancing Drp1-mitochondrial fission protein 1 (Fis1) interactions and accelerating mitochondrial fission and cardiomyocyte apoptosis [55].