The E3 ligase APC/C-Cdh1 regulates MEF2A-dependent transcription by targeting SUMO-specific protease 2 for ubiquitination and degradation

Activity-dependent stimuli induced a calcineurin-mediated dephosphorylation of the transcriptional factor MEF2A at serine408 and promoted a switch from SUMOylation to acetylation at lysine403 which led to MEF2A transcriptional activation. We previously identified SENP2 is the de-SUMOylation enzyme for MEF2A and promotes MEF2A-dependent transcription. We report here a requirement for APCCdh1-SENP2-MEF2A axis in the regulation of MEF2A transcriptional activation. APCCdh1 interacts with and targets SENP2 for ubiquitination and destruction in the cytoplasm by recognizing a conserved canonical D-box motif in SENP2. Moreover, Cdh1 regulates the transcriptional activity of MEF2A in a SENP2 dependent manner. Activity-dependent stimuli prevented APCCdh1-induced SENP2 ubiquitination, promoted SENP2 nuclear accumulations, and caused MEF2A de-SUMOylation and MEF2A acetylation, leading to MEF2A transcriptional activation. Thus, our findings defined a post-transcriptional mechanism underlying activity-dependent stimuli-induced MEF2A transcriptional activation.