Source:http://linkedlifedata.com/resource/umls/id/C1519341
NCI: The differentiation of muscle cells is transcriptionally regulated, in part by the myocyte enhancer factor-2, MEF2. During myogenesis MEF2 binds to MyoD and other basic helix-loop-helix factors to activate transcription of genes involved in muscle cell differentiation. Transcriptional activation by MEF2 is blocked by interaction with HDAC5 and other histone deacetylases. In undifferentiated myoblasts, HDAC5 is present in the nucleus where it binds to MEF2 to block activation of muscle genes. When activated by IGF-1 signaling, CaM kinase phosphorylates HDAC proteins, causing them to be exported from the nucleus, releasing the block on MEF2 transcriptional activation and allowing differentiation to proceed. Transcription cofactors also interact with MEF2 to contribute to gene regulation and myogenesis. The transcriptional regulator NFAT, for example, acts as a cofactor for MEF2 when calcium and calcineurin signaling activate it. There are four members of the Mef2 gene family, Mef2a-2d. Mef2a is expressed i