Figure 9.

Proposed model depicting the mechanism of activation of Mmp13 promoter after PTH treatment. Under basal conditions, Runx2 is bound to the RD of the Mmp13 promoter and associated with HDAC4, resulting in a repression of transcription in osteoblastic cells. MEF2C is also associated with HDAC4 at the Mmp13 promoter. After PTH treatment, HDAC4 dissociates from Runx2 and MEF2C and the latter associates with c-FOS at the AP-1 site, the complex is then free to recruit HATs, especially p300 and P/CAF to activate transcription. MEF2C also associates with p300.