MEF2 Activating Motif And SAP Domain Containing Transcriptional Regulator (MAMSTR)

MAMSTR has an N-terminal MEF2-binding domain and a central proline-rich region containing a SAP domain. Northern blot analysis of human tissues detected a 1.8-kb MASTR transcript in skeletal muscle, brain, placenta, and spleen. Real-time PCR of mouse tissues detected highest Mastr expression in skeletal muscle, lung, aorta, brain, and heart. In transfected COS cells, Mastr localized exclusively in the nucleus.Deletion and pull-down experiments showed that the N-terminal domain of Mastr was required for Mastr to associate with and activate Mef2c. Deletion of the SAP domain augmented Mastr transcriptional activity. Mutation analysis localized the transcriptional activation domain to the C-terminal half of Mastr, and deletion of this region completely abolished the ability of Mastr to stimulate Mef2-dependent transcription.