Figure 2.

MEF2 protein interactions and the mechanisms of activity regulation. MEF2 transcription factors contain MADS at their N-terminus that mediates homo and heteromerization and DNA binding. Adjacent to MADS is the MEF2 domain that regulates cofactor binding and determines DNA-binding affinity. Several MEF2-interacting partners have been identified. They may either stimulate (activators, red color) or repress MEF2 activity (repressors, blue color). PKA (protein kinase A), CKII (casein kinase II), CaMKIV (Ca²⁺/CaM-dependent protein kinase type IV), p38 kinase, ERK5 (extracellular signal-regulated kinase type 5) and PP2B (protein phosphatase type 2B) increase MEF2 activity, whereas GSK3β (glycogen synthase kinase 3β), cdk5 (cyclin-dependent kinase type 5) and caspase cleavage inhibit MEF2 activity. Adapted from [33].