Runx2 is a bone-specific transcription factor that plays a critical role in bone development,
postnatal bone formation, and chondrocyte maturation. The protein levels of Runx2 are
regulated by the ubiquitin-proteasome pathway. In previous studies we discovered that E3
ubiquitin ligase Smad ubiquitin regulatory factor 1 (Smurf1) induces Runx2 degradation in a
ubiquitin-proteasome-dependent manner, and Smurf1 plays an important role in osteoblast
function and bone formation. In the present studies we investigated the molecular …